WorldWideScience

Sample records for genetically related entamoeba

  1. Genetic diversity in Entamoeba histolytica

    Indian Academy of Sciences (India)

    C Graham Clark; Mehreen Zaki; Ibne Karim Md Ali

    2002-11-01

    Genetic diversity within Entamoeba histolytica led to the re-description of the species 10 years ago. However, more recent investigation has revealed significant diversity within the re-defined species. Both protein-coding and non-coding sequences show variability, but the common feature in all cases is the presence of short tandem repeats of varying length and sequence. The ability to identify strains of E. histolytica may lead to insights into the population structure and epidemiology of the organism.

  2. Entamoeba dispar: genetic diversity of Iranian isolates based on serine-rich Entamoeba dispar protein gene.

    Science.gov (United States)

    Haghighi, A; Rasti, S; Nazemalhosseini Mojarad, E; Kazemi, B; Bandehpour, M; Nochi, Z; Hooshyar, H; Rezaian, M

    2008-12-01

    The nucleotide sequences of Serine-Rich Entamoeba histolytica Protein (SREHP) gene have already exhibited stable and significant polymorphism in the gene studies. Serine-rich protein is also present and polymorphic in Entamoeba dispar which called SREDP. The polymorphism of the Serine-Rich Entamoeba dispar Protein (SREDP) gene among 8 isolates obtained from Iranian cyst carriers were analyzed by a nested PCR-RFLP followed by sequencing of the PCR products. From those isolates, six distinct DNA patterns were observed after PCR-RFLP of the nested PCR, whereas sequencing showed 8 different patterns among the isolates. The results demonstrate an extensive genetic variability among Iranian E. dispar isolates. The repeat-containing region of the SREDP was found extensively polymorphic in size, number and order of repeat units. Genetic diversity of Iranian E. dispar isolates based on the SREDP was more polymorphic in comparison of Serine-Rich Entamoeba histolytica Protein (SREHP) of the E. histolytica isolates as well as were different from a few known SREDP genes.

  3. Increased sampling reveals novel lineages of Entamoeba: consequences of genetic diversity and host specificity for taxonomy and molecular detection.

    Science.gov (United States)

    Stensvold, C Rune; Lebbad, Marianne; Victory, Emma L; Verweij, Jaco J; Tannich, Egbert; Alfellani, Mohammed; Legarraga, Paulette; Clark, C Graham

    2011-07-01

    To expand the representation for phylogenetic analysis, ten additional complete Entamoeba small-subunit rRNA gene sequences were obtained from humans, non-human primates, cattle and a tortoise. For some novel sequences no corresponding morphological data were available, and we suggest that these organisms should be referred to as ribosomal lineages (RL) rather than being assigned species names at present. To investigate genetic diversity and host specificity of selected Entamoeba species, a total of 91 new partial small subunit rRNA gene sequences were obtained, including 49 from Entamoeba coli, 18 from Entamoeba polecki, and 17 from Entamoeba hartmanni. We propose a new nomenclature for significant variants within established Entamoeba species. Based on current data we propose that the uninucleated-cyst-producing Entamoeba infecting humans is called Entamoeba polecki and divided into four subtypes (ST1-ST4) and that Entamoeba coli is divided into two subtypes (ST1-ST2). New hosts for several species were detected and, while host specificity and genetic diversity of several species remain to be clarified, it is clear that previous reliance on cultivated material has given us a misleading and incomplete picture of variation within the genus Entamoeba.

  4. First evidence of genetic intraspecific variability and occurrence of Entamoeba gingivalis in HIV(+)/AIDS.

    Science.gov (United States)

    Cembranelli, Sibeli B S; Souto, Fernanda O; Ferreira-Paim, Kennio; Richinho, Túlio T; Nunes, Poliana L; Nascentes, Gabriel A N; Ferreira, Thatiana B; Correia, Dalmo; Lages-Silva, Eliane

    2013-01-01

    Entamoeba gingivalis is considered an oral commensal but demonstrates a pathogenic potential associated with periodontal disease in immunocompromised individuals. Therefore, this study evaluated the occurrence, opportunistic conditions, and intraspecific genetic variability of E. gingivalis in HIV(+)/AIDS patients. Entamoeba gingivalis was studied using fresh examination (FE), culture, and PCR from bacterial plaque samples collected from 82 HIV(+)/AIDS patients. Genetic characterization of the lower ribosomal subunit of region 18S (18S-SSU rRNA) was conducted in 9 positive samples using low-stringency single specific primer PCR (LSSP-PCR) and sequencing analysis. Entamoeba gingivalis was detected in 63.4% (52/82) of the samples. No association was detected between the presence of E. gingivalis and the CD4(+) lymphocyte count (≤200 cells/mm(3) (p = 0.912) or viral load (p = 0.429). The LSSP-PCR results helped group E. gingivalis populations into 2 polymorphic groups (68.3% similarity): group I, associated with 63.6% (7/11) of the samples, and group II, associated with 36.4% (4/11) of the samples, which shared 74% and 83.7% similarity and association with C and E isolates from HIV(-) individuals, respectively. Sequencing of 4 samples demonstrated 99% identity with the reference strain ATCC 30927 and also showed 2 divergent clusters, similar to those detected by LSSP-PCR. Opportunistic behavior of E. gingivalis was not detected, which may be related to the use of highly active antiretroviral therapy by all HIV(+)/AIDS patients. The high occurrence of E. gingivalis in these patients can be influenced by multifactorial components not directly related to the CD4(+) lymphocyte counts, such as cholesterol and the oral microbiota host, which could mask the potential opportunistic ability of E. gingivalis. The identification of the 18S SSU-rRNA polymorphism by LSSP-PCR and sequencing analysis provides the first evidence of genetic variability in E. gingivalis

  5. Molecular epidemiology and genetic diversity of Entamoeba species in a chelonian collection.

    Science.gov (United States)

    García, Gabriela; Ramos, Fernando; Pérez, Rodrigo Gutiérrez; Yañez, Jorge; Estrada, Mónica Salmerón; Mendoza, Lilian Hernández; Martinez-Hernandez, Fernando; Gaytán, Paul

    2014-02-01

    Veterinary medicine has focused recently on reptiles, due to the existence of captive collections in zoos and an increase in the acquisition of reptiles as pets. The protozoan parasite, Entamoeba can cause amoebiasis in various animal species and humans. Although amoebiasis disease is remarkably rare in most species of chelonians and crocodiles, these species may serve as Entamoeba species carriers that transmit parasites to susceptible reptile species, such as snakes and lizards, which can become sick and die. In this study, we identified the Entamoeba species in a population of healthy (disease-free) chelonians, and evaluated their diversity through the amplification and sequencing of a small subunit rDNA region. Using this procedure, three Entamoeba species were identified: Entamoeba invadens in 4.76 % of chelonians, Entamoeba moshkovskii in 3.96 % and Entamoeba terrapinae in 50 %. We did not detect mixed Entamoeba infections. Comparative analysis of the amplified region allowed us to determine the intra-species variations. The E. invadens and E. moshkovskii strains isolated in this study did not exhibit marked differences with respect to the sequences reported in GenBank. The analysis of the E. terrapinae isolates revealed three different subgroups (A, B and C). Although subgroups A and C were very similar, subgroup B showed a relatively marked difference with respect to subgroups A and C (Fst = 0.984 and Fst = 1.000, respectively; 10-14 % nucleotide variation, as determined by blast) and with respect to the sequences reported in GenBank. These results suggested that E. terrapinae subgroup B may be either in a process of speciation or belong to a different lineage. However, additional research is necessary to support this statement conclusively.

  6. Genetic identification of Entamoeba polecki subtype 3 from pigs in Japan and characterisation of its pathogenic role in ulcerative colitis.

    Science.gov (United States)

    Matsubayashi, Makoto; Murakoshi, Naoko; Komatsu, Tetsuya; Tokoro, Masaharu; Haritani, Makoto; Shibahara, Tomoyuki

    2015-12-01

    To date, three Entamoeba spp. (E. suis, zoonotic E. polecki and E. histolytica) have been identified in pigs, but their pathogenicity and molecular classification have not been fully determined. Examination and pathological analysis of pigs (n=3) with diarrhoea was conducted and revealed the presence of Entamoeba organisms. We performed a genetic analysis of the isolate using the small-subunit ribosomal RNA (SSU rRNA) gene region to identify the species. A severe ulcerative colitis was observed histopathologically with inflammatory cells, including macrophages and neutrophils, infiltrating the mucous membranes of the cecum and colon. Many Entamoeba trophozoites were found at the erosion site or at ulcerative lesions. Pathogenic viruses or bacteria were not detected. The SSU rRNA sequence of the Entamoeba isolate was found to be completely homologous to that of E. polecki subtype 3.

  7. Genetic characterisation of uninucleated cyst-producing Entamoeba spp. from ruminants.

    Science.gov (United States)

    Stensvold, C Rune; Lebbad, Marianne; Clark, C Graham

    2010-06-01

    Six ssrRNA gene sequences were obtained by PCR amplification of DNA from uninucleated Entamoeba cysts isolated from fresh faeces of sheep, cows, a roe deer and a reindeer. Phylogenetic analysis using sequences of non-, uni-, quadri- and octonucleate cyst-producing Entamoeba spp. for comparison showed that all six isolates formed a separate clade nested within the clade of quadrinucleate cyst producers. The data indicate that Entamoeba bovis can be isolated from ruminant hosts other than cattle, and we suggest that organisms clustering with the sheep and cattle isolates analysed in the present study be named E. bovis.

  8. Evolutionary status of Entamoeba

    Institute of Scientific and Technical Information of China (English)

    DONG Jiuhong; WEN Jianfan; XIN Dedong; LU Siqi

    2004-01-01

    In addition to its medical importance as parasitic pathogen, Entamoeba has aroused people's interest in its evolutionary status for a long time. Lacking mitochondrion and other intracellular organelles common to typical eukaryotes, Entamoeba and several other amitochondrial protozoans have been recognized as ancient pre-mitochondriate eukaryotes and named "archezoa", the most primitive extant eukaryotes. It was suggested that they might be living fossils that remained in a primitive stage of evolution before acquisition of organelles, lying close to the transition between prokaryotes and eukaryotes. However, recent studies revealed that Entamoeba contained an organelle, "crypton" or "mitosome", which was regarded as specialized or reductive mitochondrion. Relative molecular phylogenetic analyses also indicated the existence or the probable existence of mitochondrion in Entamoeba. Our phylogenetic analysis based on DNA topoisomerase II strongly suggested its divergence after some mitchondriate eukaryotes. Here, all these recent researches are reviewed and the evolutionary status of Entamoeba is discussed.

  9. DNA repair mechanisms in eukaryotes: Special focus in Entamoeba histolytica and related protozoan parasites.

    Science.gov (United States)

    López-Camarillo, César; Lopez-Casamichana, Mavil; Weber, Christian; Guillen, Nancy; Orozco, Esther; Marchat, Laurence A

    2009-12-01

    Eukaryotic cell viability highly relies on genome stability and DNA integrity maintenance. The cellular response to DNA damage mainly consists of six biological conserved pathways known as homologous recombination repair (HRR), non-homologous end-joining (NHEJ), base excision repair (BER), mismatch repair (MMR), nucleotide excision repair (NER), and methyltransferase repair that operate in a concerted way to minimize genetic information loss due to a DNA lesion. Particularly, protozoan parasites survival depends on DNA repair mechanisms that constantly supervise chromosomes to correct damaged nucleotides generated by cytotoxic agents, host immune pressure or cellular processes. Here we reviewed the current knowledge about DNA repair mechanisms in the most relevant human protozoan pathogens. Additionally, we described the recent advances to understand DNA repair mechanisms in Entamoeba histolytica with special emphasis in the use of genomic approaches based on bioinformatic analysis of parasite genome sequence and microarrays technology.

  10. Different clinical outcomes of Entamoeba histolytica in Malaysia: does genetic diversity exist?

    Science.gov (United States)

    Anuar, Tengku Shahrul; Al-Mekhlafi, Hesham M; Abdul Ghani, Mohamed Kamel; Azreen, Siti Nor; Salleh, Fatmah Md; Ghazali, Nuraffini; Bernadus, Mekadina; Moktar, Norhayati

    2013-04-01

    The present study was conducted to investigate the clinical outcomes of Entamoeba histolytica infection in symptomatic and asymptomatic Orang Asli (aborigine) communities in Malaysia. Examination was performed on 500 stool samples obtained from Orang Asli communities in 3 different states using formalin-ether concentration, trichrome staining, and single-round PCR techniques. Out of 500 stool samples, single infection of E. histolytica, Entamoeba dispar, and Entamoeba moshkovskii was identified in 3.2%, 13.4%, and 1%, respectively. In addition, 10 samples had mixed infections with E. histolytica and E. dispar. Six samples containing E. dispar were also positive for E. moshkovskii, and only 2 samples had E. histolytica in association with E. dispar and E. moshkovskii. Seventeen E. histolytica-positive samples were from symptomatic subjects, whereas the remaining 11 samples came from asymptomatic subjects. These findings suggest a predominant distribution of pathogenic potential of E. histolytica strains in this community. Therefore, further studies on genotyping of E. histolytica is required, to find out association between E. histolytica genotype and the outcome of the infection.

  11. Different Clinical Outcomes of Entamoeba histolytica in Malaysia: Does Genetic Diversity Exist?

    Science.gov (United States)

    Anuar, Tengku Shahrul; Al-Mekhlafi, Hesham M.; Abdul Ghani, Mohamed Kamel; Azreen, Siti Nor; Salleh, Fatmah Md; Ghazali, Nuraffini; Bernadus, Mekadina

    2013-01-01

    The present study was conducted to investigate the clinical outcomes of Entamoeba histolytica infection in symptomatic and asymptomatic Orang Asli (aborigine) communities in Malaysia. Examination was performed on 500 stool samples obtained from Orang Asli communities in 3 different states using formalin-ether concentration, trichrome staining, and single-round PCR techniques. Out of 500 stool samples, single infection of E. histolytica, Entamoeba dispar, and Entamoeba moshkovskii was identified in 3.2%, 13.4%, and 1%, respectively. In addition, 10 samples had mixed infections with E. histolytica and E. dispar. Six samples containing E. dispar were also positive for E. moshkovskii, and only 2 samples had E. histolytica in association with E. dispar and E. moshkovskii. Seventeen E. histolytica-positive samples were from symptomatic subjects, whereas the remaining 11 samples came from asymptomatic subjects. These findings suggest a predominant distribution of pathogenic potential of E. histolytica strains in this community. Therefore, further studies on genotyping of E. histolytica is required, to find out association between E. histolytica genotype and the outcome of the infection. PMID:23710093

  12. Entamoeba invadens: identification of ADF/cofilin and their expression analysis in relation to encystation and excystation.

    Science.gov (United States)

    Makioka, Asao; Kumagai, Masahiro; Hiranuka, Kazushi; Kobayashi, Seiki; Takeuchi, Tsutomu

    2011-01-01

    The differentiation processes of excystation and encystation of Entamoeba are essential for infection and completion of their life-cycle, and the processes need cell motility and its control by actin cytoskeletal reorganization. This study investigated actin depolymerizing factor (ADF)/cofilin (Cfl) family proteins, which are important molecules in actin cytoskeletal reorganization, in Entamoeba invadens in relation to the encystation and excystation. Axenic culture systems were used to induce encystation and excystation. A homology search of the E. invadens genome database and molecular cloning identified three ADF/Cfl family proteins of the parasite (named for short as EiCfl-1, EiCfl-2, and EiCfl-3). This is different from other Entamoeba species, i.e. Entamoeba histolytica and Entamoeba dispar, each of which has only one ADF/Cfl family protein. These ADF/Cfl of E. invadens do not have Ser3 (serine locates third from first methionine), similar to E. histolytica, E. dispar, Saccharomyces cerevisiae and Schizosaccharomyces pombe, although the activity of ADF/Cfl is negatively regulated by phosphorylation of the Ser3 in metazoans. Phylogenetic analysis revealed that Entamoeba Cfl formed a distinctive clade that is separate from other organisms, and the branches of the tree were separated in two consistent with the presence and absence of Ser3. Rabbit anti-EiCfl-2 serum reacted with all recombinant EiCfls and EiCfl in lysates of cysts, trophozoites and metacystic amoebae. Immunofluorescence staining with this antiserum showed co-localization of EiCfl with actin beneath the cell membrane through the life stages. Both proteins proved to be rich in pseudopodia of trophozoites and metacystic amoebae. Real-time RT-PCR showed that mRNAs of EiCfl-2 and actins were highly expressed, but there were few mRNA of EiCfl-1 and EiCfl-3. Remarkably decreased mRNA levels were observed in EiCfl-2 and actins during encystation. All three EiCfls and actins became transcribed after the

  13. Genetic variability of the serine-rich Entamoeba histolytica protein gene in clinical isolates from the United Arab Emirates.

    Science.gov (United States)

    ElBakri, Ali; Samie, Amidou; Ezzedine, Sinda; Odeh, Ra'ed Abu

    2014-06-01

    The genetic diversity of 20 Entamoeba histolytica isolates from asymptomatic individuals from the UAE was investigated by analyzing polymorphism in the serine-rich E. histolytica gene (SREHP) by nested polymerase chain reaction (PCR) amplification followed by restriction fragment length polymorphism (RFLP) on DNA extracted directly from stool samples. The SREHP gene was successfully amplified in 15 out of 20 E. histolytica-positive samples. Four out of the remaining five isolates did not amplify for the SREHP gene. Despite successful amplification of the SREHP gene in the fifth isolate, AluI digestion of the amplified PCR product revealed no bands. As a result, all five samples were excluded from the study. Twelve different profiles were obtained from the 15 successfully amplified isolates. Thus, demonstrating extensive genetic variability and reinforcing the argument that E. histolytica has an extremely polymorphic genetic structure. Despite the sample size limitation, a finding in the study was the occurrence of one profile common to one Indian isolate while another profile common to one Pakistani isolate; indicating the possibility of clonal infection. Furthermore, we found one isolate from a Bangladeshi expatriate identical to 2 asymptomatic Bangladeshi isolates reported in an earlier study. No clear association between the different genotypes and the study population demographics was noted. The results also indicated the possibility of strains clustering by region.

  14. Host-Parasite interactions in Entamoeba histolytica and Entamoeba dispar: what have we learned from their genomes?

    Science.gov (United States)

    Wilson, I W; Weedall, G D; Hall, N

    2012-01-01

    Invasive amoebiasis caused by Entamoeba histolytica is a major global health problem. Virulence is a rare outcome of infection, occurring in fewer than 1 in 10 infections. Not all strains of the parasite are equally virulent, and understanding the mechanisms and causes of virulence is an important goal of Entamoeba research. The sequencing of the genome of E. histolytica and the related avirulent species Entamoeba dispar has allowed whole-genome-scale analyses of genetic divergence and differential gene expression to be undertaken. These studies have helped elucidate mechanisms of virulence and identified genes differentially expressed in virulent and avirulent parasites. Here, we review the current status of the E. histolytica and E. dispar genomes and the findings of a number of genome-scale studies comparing parasites of different virulence.

  15. Host–Parasite interactions in Entamoeba histolytica and Entamoeba dispar: what have we learned from their genomes?

    Science.gov (United States)

    Wilson, I W; Weedall, G D; Hall, N

    2012-01-01

    Invasive amoebiasis caused by Entamoeba histolytica is a major global health problem. Virulence is a rare outcome of infection, occurring in fewer than 1 in 10 infections. Not all strains of the parasite are equally virulent, and understanding the mechanisms and causes of virulence is an important goal of Entamoeba research. The sequencing of the genome of E. histolytica and the related avirulent species Entamoeba dispar has allowed whole-genome-scale analyses of genetic divergence and differential gene expression to be undertaken. These studies have helped elucidate mechanisms of virulence and identified genes differentially expressed in virulent and avirulent parasites. Here, we review the current status of the E. histolytica and E. dispar genomes and the findings of a number of genome-scale studies comparing parasites of different virulence. PMID:21810102

  16. Entamoeba histolytica rhomboid protease 1 has a role in migration and motility as validated by two independent genetic approaches.

    Science.gov (United States)

    Rastew, Elena; Morf, Laura; Singh, Upinder

    2015-07-01

    Rhomboid proteins represent a recently discovered family of intramembrane proteases present in a broad range of organisms and with increasing links to human diseases. The enteric parasite Entamoeba histolytica has evolved multiple mechanisms to adapt to the human host environment and establish infection. Our recent studies identified EhROM1 as a functional E. histolytica rhomboid protease with roles in adhesion to and phagocytosis of host cells. Since those studies were performed in a non-virulent strain, roles in parasite virulence could not be assessed. We focused this study on the comparison and validation of two genetic manipulation techniques: overexpression of a dominant-negative catalytic mutant of EhROM1 and knock down of EhROM1 using a RNAi-based silencing approach followed by functional studies of phenotypic analyses in virulent parasites. Both the EhROM1 catalytic mutant and parasites with EhROM1 downregulation were reduced in cytotoxicity, hemolytic activity, and directional and non-directional transwell migration. Importantly, the role for EhROM1 in cell migration mimics similar roles for rhomboid proteases from mammalian and apicomplexan systems. However, the EhROM1 catalytic mutant and EhROM1 downregulation parasites had different phenotypes for erythrophagocytosis, while complement resistance was not affected in either strain. In summary, in this study we genetically manipulated E. histolytica rhomboid protease EhROM1 by two different approaches and identified similarly attenuated phenotypes by both approaches, suggesting a novel role for EhROM1 in amebic motility.

  17. A Multilocus Sequence Typing System (MLST) reveals a high level of diversity and a genetic component to Entamoeba histolytica virulence

    Science.gov (United States)

    2012-01-01

    Background The outcome of an Entamoeba histolytica infection is variable and can result in either asymptomatic carriage, immediate or latent disease (diarrhea/dysentery/amebic liver abscess). An E. histolytica multilocus genotyping system based on tRNA gene-linked arrays has shown that genetic differences exist among parasites isolated from patients with different symptoms however, the tRNA gene-linked arrays cannot be located in the current assembly of the E. histolytica Reference genome (strain HM-1:IMSS) and are highly variable. Results To probe the population structure of E. histolytica and identify genetic markers associated with clinical outcome we identified in E. histolytica positive samples selected single nucleotide polymorphisms (SNPs) by multiplexed massive parallel sequencing. Profile SNPs were selected which, compared to the reference strain HM-1:IMSS sequence, changed an encoded amino acid at the SNP position, and were present in independent E. histolytica isolates from different geographical origins. The samples used in this study contained DNA isolated from either xenic strains of E. histolytica trophozoites established in culture or E. histolytica positive clinical specimens (stool and amebic liver abscess aspirates). A record of the SNPs present at 16 loci out of the original 21 candidate targets was obtained for 63 of the initial 84 samples (63% of asymptomatically colonized stool samples, 80% of diarrheal stool, 73% of xenic cultures and 84% of amebic liver aspirates). The sequences in all the 63 samples both passed sequence quality control metrics and also had the required greater than 8X sequence coverage for all 16 SNPs in order to confidently identify variants. Conclusions Our work is in agreement with previous findings of extensive diversity among E. histolytica isolates from the same geographic origin. In phylogenetic trees, only four of the 63 samples were able to group in two sets of two with greater than 50% confidence. Two SNPs in the

  18. Mitosomes in trophozoites and cysts of the reptilian parasite Entamoeba invadens.

    Science.gov (United States)

    Siegesmund, Maria A; Hehl, Adrian B; van der Giezen, Mark

    2011-11-01

    Heat shock protein genes led to the discovery of mitosomes in Entamoeba histolytica, but mitosomes have not been described for any other Entamoeba species, nor have they been identified in the cyst stage. Here, we show that the distantly related reptilian pathogen Entamoeba invadens contains mitosomes, in both trophozoites and cysts, suggesting all Entamoeba species contain these organelles.

  19. Phospholipids of Entamoeba invadens

    NARCIS (Netherlands)

    Vliet, H.H.D.M. van; Kamp, J.A.F. op den; Deenen, L.L.M. van

    1975-01-01

    The major phosphoglycerides present in Entamoeba invadens are phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol. Furthermore, three different sphingolipids could be isolated from the amoeba. In addition to sphingomyelin and a phosphonolipid, ceramide phosphon

  20. Transient and stable transfection in the protozoan parasite Entamoeba invadens.

    Science.gov (United States)

    Ehrenkaufer, Gretchen M; Singh, Upinder

    2012-07-01

    Entamoeba histolytica is an important human pathogen and a major health problem worldwide. Many aspects of parasite biology can be studied with the exception of stage conversion, which cannot be reproduced adequately in E. histolytica. The reptile parasite Entamoeba invadens is a vital model system for studying stage conversion since it can be induced to undergo both encystation and excystation with high efficiency in vitro. However, functional studies using E. invadens have been limited by the lack of genetic tools in this species. Here, we report a new method for both transient and stable transfection of E. invadens. These new tools will greatly enhance research into Entamoeba development.

  1. Diversity of clinical isolates of Entamoeba histolytica in Japan.

    Science.gov (United States)

    Nozaki, Tomoyoshi; Kobayashi, Seiki; Takeuchi, Tsutomu; Haghighi, Ali

    2006-02-01

    In Japan, amebiasis is domestically transmitted by two major populations: male homosexuals and mentally handicapped persons, which is remarkably different from most other developed countries where Entamoeba dispar infection is predominantly observed. Here we briefly summarize epidemiology of amebiasis in Japan. We also review our current understanding of the diversity of Entamoeba histolytica clinical isolates in Japan, based on polymorphic genetic markers, clinical representations, and in vivo virulence, using an animal model.

  2. A simple fibril and lectin model for cyst walls of Entamoeba and perhaps Giardia.

    Science.gov (United States)

    Samuelson, John; Robbins, Phillips

    2011-01-01

    Cyst walls of Entamoeba and Giardia protect them from environmental insults, stomach acids, and intestinal proteases. Each cyst wall contains a sugar homopolymer: chitin in Entamoeba and a unique N-acetylgalactosamine (GalNAc) homopolymer in Giardia. Entamoeba cyst wall proteins include Jacob lectins (carbohydrate-binding proteins) that crosslink chitin, chitinases that degrade chitin, and Jessie lectins that make walls impermeable. Giardia cyst wall proteins are also lectins that bind fibrils of the GalNAc homopolymer. Although many of the details remain to be determined for the cyst wall of Giardia, current data suggest a relatively simple fibril and lectin model for the Entamoeba cyst wall.

  3. A simple fibril and lectin model for cyst walls of Entamoeba and perhaps Giardia

    Science.gov (United States)

    Samuelson, John; Robbins, Phillips

    2010-01-01

    Cyst walls of Entamoeba and Giardia protect them from environmental insults, stomach acids, and intestinal proteases. Each cyst wall contains a sugar homopolymer: chitin in Entamoeba and a unique N-acetylgalactosamine (GalNAc) homopolymer in Giardia. Entamoeba cyst wall proteins include Jacob lectins (carbohydrate-binding proteins) that cross-link chitin, chitinases that degrade chitin, and Jessie lectins that make walls impermeable. Giardia cyst wall proteins are also lectins that bind fibrils of the GalNAc homopolymer. While many of the details remain to be determined for the Giardia cyst wall, current data suggests a relatively simple fibril and lectin model for the Entamoeba cyst wall. PMID:20934911

  4. Homologous recombination occurs in Entamoeba and is enhanced during growth stress and stage conversion.

    Directory of Open Access Journals (Sweden)

    Nishant Singh

    Full Text Available Homologous recombination (HR has not been demonstrated in the parasitic protists Entamoeba histolytica or Entamoeba invadens, as no convenient method is available to measure it. However, HR must exist to ensure genome integrity, and possible genetic exchange, especially during stage conversion from trophozoite to cyst. Here we show the up regulation of mitotic and meiotic HR genes in Entamoeba during serum starvation, and encystation. To directly demonstrate HR we use a simple PCR-based method involving inverted repeats, which gives a reliable read out, as the recombination junctions can be determined by sequencing the amplicons. Using this read out, we demonstrate enhanced HR under growth stress in E. histolytica, and during encystation in E. invadens. We also demonstrate recombination between chromosomal inverted repeats. This is the first experimental demonstration of HR in Entamoeba and will help future investigations into this process, and to explore the possibility of meiosis in Entamoeba.

  5. Homologous recombination occurs in Entamoeba and is enhanced during growth stress and stage conversion.

    Science.gov (United States)

    Singh, Nishant; Bhattacharya, Alok; Bhattacharya, Sudha

    2013-01-01

    Homologous recombination (HR) has not been demonstrated in the parasitic protists Entamoeba histolytica or Entamoeba invadens, as no convenient method is available to measure it. However, HR must exist to ensure genome integrity, and possible genetic exchange, especially during stage conversion from trophozoite to cyst. Here we show the up regulation of mitotic and meiotic HR genes in Entamoeba during serum starvation, and encystation. To directly demonstrate HR we use a simple PCR-based method involving inverted repeats, which gives a reliable read out, as the recombination junctions can be determined by sequencing the amplicons. Using this read out, we demonstrate enhanced HR under growth stress in E. histolytica, and during encystation in E. invadens. We also demonstrate recombination between chromosomal inverted repeats. This is the first experimental demonstration of HR in Entamoeba and will help future investigations into this process, and to explore the possibility of meiosis in Entamoeba.

  6. Evolutionary genomics and population structure of Entamoeba histolytica

    Science.gov (United States)

    Das, Koushik; Ganguly, Sandipan

    2014-01-01

    Amoebiasis caused by the gastrointestinal parasite Entamoeba histolytica has diverse disease outcomes. Study of genome and evolution of this fascinating parasite will help us to understand the basis of its virulence and explain why, when and how it causes diseases. In this review, we have summarized current knowledge regarding evolutionary genomics of E. histolytica and discussed their association with parasite phenotypes and its differential pathogenic behavior. How genetic diversity reveals parasite population structure has also been discussed. Queries concerning their evolution and population structure which were required to be addressed have also been highlighted. This significantly large amount of genomic data will improve our knowledge about this pathogenic species of Entamoeba. PMID:25505504

  7. Susceptibility to Entamoeba histolytica intestinal infection is related to reduction in natural killer T-lymphocytes in C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Fabrício M.S. Oliveira

    2012-04-01

    Full Text Available Entamoeba histolytica is a protozoan that causes amoebiasis. Recent studies demonstrated that natural killer T lymphocytes (NKT are critical for preventing the development of amoebic liver abscess. In spite of that, there are only a handful of studies in the area. Herein, we explored the role of NKT cells in E. histolytica infection using C57BL/6 wild-type and CD1-/- mice. Animals were inoculated with E. histolytica and sacrificed 48 hours later to collect caecum samples that were used for quantitative analyses of lesions, trophozoites, NK1.1+ T lymphocytes and expression of the mucus protein MUC-2 by immunohistochemistry technique. Quantitative analyses confirmed that the frequency of NK1.1+ T cells was significantly lower in samples from C57BL/6 CD1-/- mice as compared to their wild type (WT counterparts. The extension of necrotic mucosa was larger and the number of trophozoites higher in Entamoeba (Eh-infected CD1-/- mice when compared with Eh-infected WT mice. In mice from both groups, noninfected (CTRL and Eh-infected CD1-/-, there was a reduction in the thickness of the caecal mucosa and in the MUC-2-stained area in comparison with CTRL- and Eh-WT mice. Our results showed that NKT lymphocytes contribute to resistance against Entamoeba histolytica infection and to the control of inflammation in the colitis induced by infection. The presence of a normal epithelial layer containing appropriate levels of mucus had also a protective role against infection.

  8. Uso da bioinformática na diferenciação molecular da Entamoeba histolytica e Entamoeba díspar = Molecular discrimination of Entamoeba histolytica and Entamoeba dispar by bioinformatics resources

    Directory of Open Access Journals (Sweden)

    Eliane Gasparino

    2008-07-01

    Full Text Available Amebíase invasiva, causada por Entamoeba histolytica, é microscopicamente indistinguível da espécie não-patogênica Entamoeba dispar. Com auxílio de ferramentas de bioinformática, objetivou-se diferenciar Entamoeba histolytica e Entamoeba dispar por técnicasmoleculares. A análise foi realizada a partir do banco de dados da National Center for Biotechnology Information; pela pesquisa de similaridade de sequências, elegeu-se o gene da cisteína sintase. Um par de primer foi desenhado (programa Web Primer e foi selecionada a enzima de restrição TaqI (programa Web Cutter. Após a atuação da enzima, o fragmento foi dividido em dois, um com 255 pb e outro com 554 pb, padrão característico da E. histolytica. Na ausência de corte, o fragmento apresentou o tamanho de 809 pb, referente à E. dispar.Under microscopic conditions, the invasive Entamoeba histolytica is indistinguishable from the non-pathogenic species Entamoeba dispar. In this way, the present study was carried out to determine a molecular strategy for discriminating both species by the mechanisms of bioinformatics. The gene cysteine synthetase was consideredfor such a purpose by using the resources of the National Center for Biotechnology Information data bank in the search for similarities in the gene sequence. In this way, a primer pair was designed by the Web Primer program and the restriction enzyme TaqI was selected by the Web Cutter software program. The DNA fragment had a size of 809 bpbefore cutting, which is consistent with E. dispar. The gene fragment was partitioned in a first fragment with 255 bp and a second one with 554 bp, which is similar to the genetic characteristics of E. histolytica.

  9. Differential expression of surface glycoconjugates on Entamoeba histolytica and Entamoeba dispar.

    Science.gov (United States)

    Pacheco-Yépez, Judith; Campos-Rodríguez, Rafael; Rojas-Hernández, Saúl; Serrano-Luna, José J; Rivera-Aguilar, Víctor; Villa-Treviño, Saúl; Martínez-Palomo, Adolfo; Tsutsumi, Víctor; Shibayama, Mineko

    2009-06-01

    The human large intestine can harbor two morphologically similar amoebae; the invasive Entamoeba histolytica and the non-invasive Entamoeba dispar. Whereas E. histolytica can produce intestinal and extra-intestinal lesions, E. dispar is present in non-symptomatic carriers. Although biochemical, genetic and proteomic studies have identified clear differences between these Entamoebae, it has become clear that several molecules, once assumed to be involved in tissue destruction, exist in both the virulent and the avirulent species. As surface molecules may play a role in invasion and could therefore determine which amoebae are invasive, we analyzed the glycoconjugate composition of E. histolytica and E. dispar using lectins. There was a significant difference between E. histolytica and E. dispar in the expression of glycoconjugates containing d-mannose and N-acetyl-alpha-D-galactosamine residues, but not between virulent and avirulent strains of E. histolytica. N-glycoconjugates with terminal alpha (1-3)-linked mannose residues participate in the adhesion and subsequent cytotoxicity of E. histolytica to cultured hamster hepatocytes. One of them probably is the Gal/GalNAc lectin.

  10. Entamoeba dispar: Could it be pathogenic

    National Research Council Canada - National Science Library

    FabrÍcio Oliveira; Elisabeth Neumann; Maria Gomes; Marcelo Caliari

    2015-01-01

      Amebiasis is a disease caused by the protozoan parasite Entamoeba histolytica. This ameba can colonize the human intestine and persist as a commensal parasite, similar to Entamoeba dispar, an ameba considered to be non-pathogenic...

  11. Laboratory methods of identification of Entamoeba histolytica and its differentiation from look-alike Entamoeba spp.

    OpenAIRE

    Parija, Subhash Chandra; Mandal, Jharna; Ponnambath, Dinoop Korol

    2014-01-01

    Entamoeba histolytica, the causative agent of intestinal and extraintestinal amebiasis, is a common parasitic cause of significant morbidity and mortality in the developing countries. Hence, early detection and differentiation of pathogenic E. histolytica from nonpathogenic/commensal Entamoeba spp (Entamoeba dispar/Entamoeba moshkovskii/Entamoeba bangladeshi) plays a crucial role in clinical management of patients with amebiasis. Most diagnostic tests currently available do not reliably diffe...

  12. Entamoeba histolytica: observations on metabolism based on thegenome sequence

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iain J.; Loftus, Brendan J.

    2005-07-01

    The sequencing of the genome of Entamoeba histolytica has allowed a reconstruction of its metabolic pathways, many of which are unusual for a eukaryote. Based on the genome sequence, it appears that amino acids may play a larger role than previously thought in energy metabolism, with roles in both ATP synthesis and NAD regeneration. Arginine decarboxylase may be involved in survival of E. histolytica during its passage through the stomach. The usual pyrimidine synthesis pathway is absent, but a partial pyrimidine degradation pathway could be part of a novel pyrimidine synthesis pathway. Ribonucleotide reductase was not found in the E. histolytica genome, but it was found in the close relatives Entamoeba invadens and Entamoeba moshkovskii, suggesting a recent loss from E. histolytica. The usual eukaryotic glucose transporters are not present, but members of a prokaryotic monosaccharide transporter family are present.

  13. Ocorrência de Entamoeba histolytica/Entamoeba dispar em pacientes ambulatoriais de Recife, PE Occurrence of Entamoeba histolytica/Entamoeba dispar in ambulatory patients of Recife, PE

    Directory of Open Access Journals (Sweden)

    Antônio Dourado

    2006-08-01

    Full Text Available Este trabalho teve como objetivo determinar a ocorrência das espécies Entamoeba histolytica/Entamoeba dispar em amostras clínicas de pacientes ambulatoriais de Pernambuco. Neste estudo, foi utilizado o teste imunoenzimático específico para Entamoeba histolytica, que entre os 213 pacientes não identificou nenhuma amostra fecal positiva. Estes resultados confirmam Entamoeba dispar é a espécie dominante nesta região.The objective this study was to determine the occurrence of the species Entamoeba histolytica/Entamoeba díspar in clinical samples of ambulatory patients in Pernambuco. A specific assay for Entamoeba histolytica was used in this study, which identified no positive fecal samples among the 213 patients. These results confirm that E. dispar is the dominant species in Pernambuco State.

  14. Molecular modeling on pyruvate phosphate dikinase of Entamoeba histolytica and in silico virtual screening for novel inhibitors

    Science.gov (United States)

    Stephen, Preyesh; Vijayan, Ramachandran; Bhat, Audesh; Subbarao, N.; Bamezai, R. N. K.

    2008-09-01

    Pyruvate phosphate dikinase (PPDK) is the key enzyme essential for the glycolytic pathway in most common and perilous parasite Entamoeba histolytica. Inhibiting the function of this enzyme could control the wide spread of intestinal infections caused by Entamoeba histolytica in humans. With this objective, we modeled the three dimensional structure of the PPDK protein. We used templates with 51% identity and 67% similarity to employ homology-modeling approach. Stereo chemical quality of protein structure was validated by protein structure validation program PROCHECK and VERIFY3D. Experimental proof available in literature along with the in silico studies indicated Lys21, Arg91, Asp323, Glu325 and Gln337 to be the probable active sites in the target protein. Virtual screening was carried out using the genetic docking algorithm GOLD and a consensus scoring function X-Score to substantiate the prediction. The small molecule libraries (ChemDivision database, Diversity dataset, Kinase inhibitor database) were used for screening process. Along with the high scoring results, the interaction studies provided promising ligands for future experimental screening to inhibit the function of PPDK in Entamoeba histolytica. Further, the phylogeny study was carried out to assess the possibility of using the proposed ligands as inhibitors in related pathogens.

  15. Entamoeba histolytica and Entamoeba dispar infection in Mexican school children: genotyping and phylogenetic relationship.

    Science.gov (United States)

    Rojas, Liliana; Morán, Patricia; Valadez, Alicia; Gómez, Alejandro; González, Enrique; Hernández, Eric; Partida, Oswaldo; Nieves, Miriam; Gudiño, Marco; Magaña, Ulises; Torres, Javier; Ximénez, Cecilia

    2016-09-13

    This study aimed to determine the frequency of Entamoeba histolytica and Entamoeba dispar infection in school children in the community of Tlaltizapan, in order to understand the dynamics of infection within the school and family spheres of this population. Amoebiasis is an unsolved public health problem and an endemic disease in Mexico. The incidence rate varies depending on the state; the most affected states show the highest numbers of new cases of amoebiasis per year. Previously, we reported the molecular frequency of infection with E. histolytica and/or E. dispar in other rural communities of the state of Morelos. Children from 3 schools were studied to estimate the frequency of intestinal parasites through microscopic examination of fresh stool samples. The number of studied individuals were 309 school children. The molecular characterization of E. histolytica or E. dispar was carried out by Polymerase Chain Reaction (PCR) using species-specific primers to amplify short tandem repeats (STR) in non-coding sequences associated with the tRNA gene; the amplified fragments were sequenced and analyzed. Eight different genotypes were obtained from E. dispar isolates with the molecular marker NKD3-D5. None of the cases in which the species E. histolytica was detected developed symptoms attributable to an invasive process of disease. Moreover, the parasitized condition appeared to have no significant impact on the development or nutritional status of affected children. Genotype 1, which corresponds to the reference strain E. dispar SAW760, considered a non-pathogenic amoeba, was the most prevalent. The comparison of the genotypes of Entamoeba species did not show a correlation between children and their relatives. In this community, the species Entamoeba dispar genotype 1 was the most widespread. Based on the indicators of growth, development and nutrition status, the studied community seems to be reasonably adapted to constant exposure to intestinal parasites, since

  16. Species-specific immunity induced by infection with Entamoeba histolytica and Entamoeba moshkovskii in mice.

    Science.gov (United States)

    Shimokawa, Chikako; Culleton, Richard; Imai, Takashi; Suzue, Kazutomo; Hirai, Makoto; Taniguchi, Tomoyo; Kobayashi, Seiki; Hisaeda, Hajime; Hamano, Shinjiro

    2013-01-01

    Entamoeba histolytica, the parasitic amoeba responsible for amoebiasis, causes approximately 100,000 deaths every year. There is currently no vaccine against this parasite. We have previously shown that intracecal inoculation of E. histolytica trophozoites leads to chronic and non-healing cecitis in mice. Entamoeba moshkovskii, a closely related amoeba, also causes diarrhea and other intestinal disorders in this model. Here, we investigated the effect of infection followed by drug-cure of these species on the induction of immunity against homologous or heterologous species challenge. Mice were infected with E. histolytica or E. moshkovskii and treated with metronidazole 14 days later. Re-challenge with E. histolytica or E. moshkovskii was conducted seven or 28 days following confirmation of the clearance of amoebae, and the degree of protection compared to non-exposed control mice was evaluated. We show that primary infection with these amoebae induces a species-specific immune response which protects against challenge with the homologous, but not a heterologous species. These findings pave the way, therefore, for the identification of novel amoebae antigens that may become the targets of vaccines and provide a useful platform to investigate host protective immunity to Entamoeba infections.

  17. Differences in cap formation between invasive Entamoeba histolytica and non-invasive Entamoeba dispar.

    Science.gov (United States)

    Chávez-Munguía, Bibiana; Talamás-Rohana, Patricia; Castañón, Guadalupe; Salazar-Villatoro, Lizbeth; Hernández-Ramírez, Verónica; Martínez-Palomo, Adolfo

    2012-07-01

    The rapid redistribution of surface antigen-antibody complexes in trophozoites of the human protozoan parasite Entamoeba histolytica, in a process known as capping, has been considered as a means of the parasite to evade the host immune response. So far, capping has been documented in the invasive E. histolytica, whereas the mobility of surface components in the non-invasive Entamoeba dispar is not known. E. dispar does not induce liver lesions in rodent experimental models, in contrast to the liver abscesses produced by E. histolytica in the same animal model. We have therefore analyzed the mobility of surface receptors to the lectin concanavalin A and of Rab11, a membrane-associated protein, in both species of Entamoebae by confocal fluorescence microscopy and transmission and scanning electron microscopy. The great majority of E. histolytica trophozoites became morphologically polarized through the formation of well-defined caps at the posterior pole of the parasite. Actin colocalized with the lectin caps. Antibodies against the membrane protein Rab 11 also produced capping. In striking contrast, in E. dispar, the mobility of concanavalin A surface receptors was restricted to the formation of irregular surface patches that did no progress to constitute well-defined caps. Also, anti-Rab 11 antibodies did not result in capping in E. dispar. Whether the failure of E. dispar to efficiently mobilize surface molecules in response to lectin or antibodies as shown in the present results is related to its non-invasive character represents an interesting hypothesis requiring further analysis.

  18. Species-specific immunity induced by infection with Entamoeba histolytica and Entamoeba moshkovskii in mice.

    Directory of Open Access Journals (Sweden)

    Chikako Shimokawa

    Full Text Available Entamoeba histolytica, the parasitic amoeba responsible for amoebiasis, causes approximately 100,000 deaths every year. There is currently no vaccine against this parasite. We have previously shown that intracecal inoculation of E. histolytica trophozoites leads to chronic and non-healing cecitis in mice. Entamoeba moshkovskii, a closely related amoeba, also causes diarrhea and other intestinal disorders in this model. Here, we investigated the effect of infection followed by drug-cure of these species on the induction of immunity against homologous or heterologous species challenge. Mice were infected with E. histolytica or E. moshkovskii and treated with metronidazole 14 days later. Re-challenge with E. histolytica or E. moshkovskii was conducted seven or 28 days following confirmation of the clearance of amoebae, and the degree of protection compared to non-exposed control mice was evaluated. We show that primary infection with these amoebae induces a species-specific immune response which protects against challenge with the homologous, but not a heterologous species. These findings pave the way, therefore, for the identification of novel amoebae antigens that may become the targets of vaccines and provide a useful platform to investigate host protective immunity to Entamoeba infections.

  19. Variation in Rural African Gut Microbiota Is Strongly Correlated with Colonization by Entamoeba and Subsistence.

    Directory of Open Access Journals (Sweden)

    Elise R Morton

    2015-11-01

    Full Text Available The human gut microbiota is impacted by host nutrition and health status and therefore represents a potentially adaptive phenotype influenced by metabolic and immune constraints. Previous studies contrasting rural populations in developing countries to urban industrialized ones have shown that industrialization is strongly correlated with patterns in human gut microbiota; however, we know little about the relative contribution of factors such as climate, diet, medicine, hygiene practices, host genetics, and parasitism. Here, we focus on fine-scale comparisons of African rural populations in order to (i contrast the gut microbiota of populations inhabiting similar environments but having different traditional subsistence modes and either shared or distinct genetic ancestry, and (ii examine the relationship between gut parasites and bacterial communities. Characterizing the fecal microbiota of Pygmy hunter-gatherers as well as Bantu individuals from both farming and fishing populations in Southwest Cameroon, we found that the gut parasite Entamoeba is significantly correlated with microbiome composition and diversity. We show that across populations, colonization by this protozoa can be predicted with 79% accuracy based on the composition of an individual's gut microbiota, and that several of the taxa most important for distinguishing Entamoeba absence or presence are signature taxa for autoimmune disorders. We also found gut communities to vary significantly with subsistence mode, notably with some taxa previously shown to be enriched in other hunter-gatherers groups (in Tanzania and Peru also discriminating hunter-gatherers from neighboring farming or fishing populations in Cameroon.

  20. Variation in Rural African Gut Microbiota Is Strongly Correlated with Colonization by Entamoeba and Subsistence.

    Science.gov (United States)

    Morton, Elise R; Lynch, Joshua; Froment, Alain; Lafosse, Sophie; Heyer, Evelyne; Przeworski, Molly; Blekhman, Ran; Ségurel, Laure

    2015-11-01

    The human gut microbiota is impacted by host nutrition and health status and therefore represents a potentially adaptive phenotype influenced by metabolic and immune constraints. Previous studies contrasting rural populations in developing countries to urban industrialized ones have shown that industrialization is strongly correlated with patterns in human gut microbiota; however, we know little about the relative contribution of factors such as climate, diet, medicine, hygiene practices, host genetics, and parasitism. Here, we focus on fine-scale comparisons of African rural populations in order to (i) contrast the gut microbiota of populations inhabiting similar environments but having different traditional subsistence modes and either shared or distinct genetic ancestry, and (ii) examine the relationship between gut parasites and bacterial communities. Characterizing the fecal microbiota of Pygmy hunter-gatherers as well as Bantu individuals from both farming and fishing populations in Southwest Cameroon, we found that the gut parasite Entamoeba is significantly correlated with microbiome composition and diversity. We show that across populations, colonization by this protozoa can be predicted with 79% accuracy based on the composition of an individual's gut microbiota, and that several of the taxa most important for distinguishing Entamoeba absence or presence are signature taxa for autoimmune disorders. We also found gut communities to vary significantly with subsistence mode, notably with some taxa previously shown to be enriched in other hunter-gatherers groups (in Tanzania and Peru) also discriminating hunter-gatherers from neighboring farming or fishing populations in Cameroon.

  1. Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-Related Cancer in Women

    Science.gov (United States)

    ... Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-related Cancer in Women The U.S. Preventive Services ... Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-related Cancer in Women. This final recommendation statement ...

  2. Nonpathogenic Entamoeba dispar quickly outgrows pathogenic Entamoeba histolytica in mixed xenic cultures.

    Science.gov (United States)

    Pysova, I; Tumova, P; Tolarova, V; Nohynkova, E

    2009-04-01

    Entamoeba histolytica and Entamoeba dispar are two microscopically indistinguishable amoebae living in the human colon. The former is a pathogen, whereas the latter is a nonpathogenic commensal. Using a model system of in vitro cocultures and PCR detection of the Entamoeba species, we found that the nonpathogenic species can rapidly outgrow the pathogen in xenic cultures.

  3. Conservation and function of Rab small GTPases in Entamoeba: annotation of E. invadens Rab and its use for the understanding of Entamoeba biology.

    Science.gov (United States)

    Nakada-Tsukui, Kumiko; Saito-Nakano, Yumiko; Husain, Afzal; Nozaki, Tomoyoshi

    2010-11-01

    Entamoeba invadens is a reptilian enteric protozoan parasite closely related to the human pathogen Entamoeba histolytica and a good model organism of encystation. To understand the molecular mechanism of vesicular trafficking involved in the encystation of Entamoeba, we examined the conservation of Rab small GTPases between the two species. E. invadens has over 100 Rab genes, similar to E. histolytica. Most of the Rab subfamilies are conserved between the two species, while a number of species-specific Rabs are also present. We annotated all E. invadens Rabs according to the previous nomenclature [Saito-Nakano, Y., Loftus, B.J., Hall, N., Nozaki, T., 2005. The diversity of Rab GTPases in Entamoeba histolytica. Experimental Parasitology 110, 244-252]. Comparative genomic analysis suggested that the fundamental vesicular traffic machinery is well conserved, while there are species-specific protein transport mechanisms. We also reviewed the function of Rabs in Entamoeba, and proposed the use of the annotation of E. invadens Rab genes to understand the ubiquitous importance of Rab-mediated membrane trafficking during important biological processes including differentiation in Entamoeba.

  4. Evolutionary genomics and population structure of Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Koushik Das

    2014-11-01

    Full Text Available Amoebiasis caused by the gastrointestinal parasite Entamoeba histolytica has diverse disease outcomes. Study of genome and evolution of this fascinating parasite will help us to understand the basis of its virulence and explain why, when and how it causes diseases. In this review, we have summarized current knowledge regarding evolutionary genomics of E. histolytica and discussed their association with parasite phenotypes and its differential pathogenic behavior. How genetic diversity reveals parasite population structure has also been discussed. Queries concerning their evolution and population structure which were required to be addressed have also been highlighted. This significantly large amount of genomic data will improve our knowledge about this pathogenic species of Entamoeba.

  5. DNA characterization of simian Entamoeba histolytica-like strains to differentiate them from Entamoeba histolytica.

    Science.gov (United States)

    Takano, Jun-ichiro; Tachibana, Hiroshi; Kato, Miyoko; Narita, Toyoko; Yanagi, Tetsuo; Yasutomi, Yasuhiro; Fujimoto, Koji

    2009-10-01

    Two simian Entamoeba histolytica-like strains, EHMfas1 and P19-061405, have been suggested to represent a new species based on genetic characterization. Sequence analyses of the hexokinase, glucose phosphate isomerase, and phosphoglucomutase genes supported the previous findings of isoenzyme analyses demonstrating a new zymodeme pattern. Phylogenetic studies of 18S rDNA, 5.8S rDNA, the chaperonin 60 gene, and the pyridine nucleotide transhydrogenase gene showed original clusters of simian E. histolytica-like strains below or near E. histolytica, respectively. Comparative studies of the chitinase and the serine-rich E. histolytica protein genes and locus 1-2 region revealed that most mutated units were shared among the simian E. histolytica-like strains. The similarities of each of the repeating units within the simian E. histolytica-like strains or E. histolytica and the differences of those between the both might be generated by concerted evolution. Our results indicate that EHMfas1 and P19-061405 should be considered to be the same species, despite that they were isolated from different monkey species and different habitats. Simian E. histolytica-like amebas may be endemic to macaque monkeys, as a counterpart to E. histolytica in humans, and should be differentiated from E. histolytica by the revival name Entamoeba nuttalli, as proposed for P19-061405.

  6. The diagnostic implications of the separation of Entamoeba histolytica and Entamoeba dispar

    Indian Academy of Sciences (India)

    J P Ackers

    2002-11-01

    For much of the last hundred years most cases of amoebiasis have been diagnosed by light microscopy. Only relatively recently have we become aware that this technique is usually incapable of distinguishing between two species – Entamoeba histolytica and E. dispar – only the first of which is a pathogen. The implications of this for patient management and, even more, for the validity of epidemiological surveys, are only slowly being addressed. What is clear is that methods are urgently required to distinguish between infections with these two species and this review attempts to summarise some of those, which have been developed to meet this need.

  7. Ultrastructural characteristics and molecular identification of Entamoeba suis isolated from pigs with hemorrhagic colitis: implications for pathogenicity.

    Science.gov (United States)

    Matsubayashi, Makoto; Suzuta, Fumiko; Terayama, Yoshimi; Shimojo, Kengo; Yui, Takeshi; Haritani, Makoto; Shibahara, Tomoyuki

    2014-08-01

    Protozoan parasites of the genus Entamoeba infect many classes of vertebrates and are primarily classified based on morphological criteria. To date, only a few species have been proven to cause disease. Here, we examined the pathology of infected pigs with hemorrhage and detected Entamoeba parasites. Isolates were characterized genetically and ultrastructurally to identify the species. Histopathologically, bleeding and thrombus formation were seen only in the large intestine mucosa, where a large number of trophozoites or some Entamoeba cysts were observed around breakdowns in the lamina propria. No screw-shaped bacteria were detected in the lesions, and no pathogenic bacteria such as Brachyspira spp. were detected in fecal cultures. Interestingly, electron microscopy revealed that the parasites possessed mitochondrial organelles, unlike other Entamoeba spp. The isolates were identified as Entamoeba suis by PCR analysis and sequencing of the small subunit ribosomal RNA (SSU rRNA) gene. In phylogenetic analyses based on the actin gene, the E. suis isolate formed a cluster with Entamoeba histolytica and Entamoeba invadens, as well as with other parasites of the Amoebidae. Whether the pathogenicity of the E. suis isolate is affected by the severity of infection or host health status remains unclear; however, our results suggest that E. suis could cause or exacerbate clinical symptoms such as hemorrhagic colitis or diarrhea.

  8. 21 CFR 866.3220 - Entamoeba histolytica serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Entamoeba histolytica serological reagents. 866... Entamoeba histolytica serological reagents. (a) Identification. Entamoeba histolytica serological reagents... Entamoeba histolytica in serum. Additionally, some of these reagents consist of antisera conjugated with...

  9. Molecular differentiation of Entamoeba histolytica and Entamoeba dispar from Tunisian food handlers with amoeba infection initially diagnosed by microscopy

    Directory of Open Access Journals (Sweden)

    Ben Ayed S.

    2008-03-01

    Full Text Available The purpose of the study was to obtain more reliable epidemiological data concerning Entamoeba (E. histolytica infection in Tunisian food handlers using established molecular tools able to differentiate E. histolytica from E. dispar. From 2002 to 2005, 4,266 fresh stools specimens received in the setting of the National program of food handlers’ control were analysed by optical microscopy. Twelve (2.8 ‰ were positive for the presence of four nuclei cysts identified as E. histolytica/E. dispar. Extraction of DNA from the 12 samples, followed by specific amplifications of E. histolytica and E. dispar SSU rDNA, showed that 11 samples (92% were positive for E. dispar and negative for E. histolytica. Sequencing analysis of 8 PCR products permitted to verify the results obtained with conventional PCR. The remaining sample was negative by PCR amplifying E. histolytica DNA or E. dispar DNA specifically, although it did not show any inhibition. It probably contains protozoan cysts genetically distinct from these two species but morphological similar. Estimation of relative proportions between E. histolytica and E. dispar in cyst carriers showed that all explored individuals harboured the non pathogenic E. dispar strains. This result highlights the need of use in this population of complementary tests that allow specific diagnosis and obviate unnecessary chemotherapy.

  10. Transcriptome analysis of encystation in Entamoeba invadens.

    Directory of Open Access Journals (Sweden)

    Aleyla Escueta De Cádiz

    Full Text Available Encystation is an essential differentiation process for the completion of the life cycle of a group of intestinal protozoa including Entamoeba histolytica, the causative agent of intestinal and extraintestinal amebiasis. However, regulation of gene expression during encystation is poorly understood. To comprehensively understand the process at the molecular level, the transcriptomic profiles of E. invadens, which is a related reptilian species that causes an invasive disease similar to that of E. histolytica, was investigated during encystation. Using a custom-generated Affymetrix platform microarray, we performed time course (0.5, 2, 8, 24, 48, and 120 h gene expression analysis of encysting E. invadens. ANOVA analysis revealed that a total of 1,528 genes showed ≥3 fold up-regulation at one or more time points, relative to the trophozoite stage. Of these modulated genes, 8% (116 genes were up-regulated at the early time points (0.5, 2 and 8h, while 63% (962 genes were up-regulated at the later time points (24, 48, and 120 h. Twenty nine percent (450 genes are either up-regulated at 2 to 5 time points or constitutively up-regulated in both early and late stages. Among the up-regulated genes are the genes encoding transporters, cytoskeletal proteins, proteins involved in vesicular trafficking (small GTPases, Myb transcription factors, cysteine proteases, components of the proteasome, and enzymes for chitin biosynthesis. This study represents the first kinetic analysis of gene expression during differentiation from the invasive trophozoite to the dormant, infective cyst stage in Entamoeba. Functional analysis on individual genes and their encoded products that are modulated during encystation may lead to the discovery of targets for the development of new chemotherapeutics that interfere with stage conversion of the parasite.

  11. Transcriptome analysis of encystation in Entamoeba invadens.

    Science.gov (United States)

    De Cádiz, Aleyla Escueta; Jeelani, Ghulam; Nakada-Tsukui, Kumiko; Caler, Elisabet; Nozaki, Tomoyoshi

    2013-01-01

    Encystation is an essential differentiation process for the completion of the life cycle of a group of intestinal protozoa including Entamoeba histolytica, the causative agent of intestinal and extraintestinal amebiasis. However, regulation of gene expression during encystation is poorly understood. To comprehensively understand the process at the molecular level, the transcriptomic profiles of E. invadens, which is a related reptilian species that causes an invasive disease similar to that of E. histolytica, was investigated during encystation. Using a custom-generated Affymetrix platform microarray, we performed time course (0.5, 2, 8, 24, 48, and 120 h) gene expression analysis of encysting E. invadens. ANOVA analysis revealed that a total of 1,528 genes showed ≥3 fold up-regulation at one or more time points, relative to the trophozoite stage. Of these modulated genes, 8% (116 genes) were up-regulated at the early time points (0.5, 2 and 8h), while 63% (962 genes) were up-regulated at the later time points (24, 48, and 120 h). Twenty nine percent (450 genes) are either up-regulated at 2 to 5 time points or constitutively up-regulated in both early and late stages. Among the up-regulated genes are the genes encoding transporters, cytoskeletal proteins, proteins involved in vesicular trafficking (small GTPases), Myb transcription factors, cysteine proteases, components of the proteasome, and enzymes for chitin biosynthesis. This study represents the first kinetic analysis of gene expression during differentiation from the invasive trophozoite to the dormant, infective cyst stage in Entamoeba. Functional analysis on individual genes and their encoded products that are modulated during encystation may lead to the discovery of targets for the development of new chemotherapeutics that interfere with stage conversion of the parasite.

  12. Inhibitory and lytic effects of phenothiazine derivatives and related tricyclic neuroleptic compounds, on Entamoeba histolytica HK9 and HM1 trophozoites.

    Science.gov (United States)

    Ondarza, R N; Hernández, E; Iturbe, A; Hurtado, G

    2000-08-01

    It has been shown previously that tricyclic neuroleptics like clomipramine and chlorpromazine have lethal effects on Leishmania donovani and L. major, and other studies indicate that the phenothiazine inhibitors of trypanothione reductase are potential anti-trypanosomal and anti-leishmanial drugs. With this in mind and our original observation on the presence of trypanothione in Entamoeba histolytica HK9, we examined the possible inhibitory effects of various phenothiazine and tricyclic derivatives on this human parasite. We found that drugs like clomipramine (KD002), the most potent in vitro inhibitor of trypanothione reductase among 30 tricyclic compounds tested, at 25 microM after 24 h of culture under aerobic conditions, caused a substantial decrease in the number of E. histolytica HK9 trophozoites, from approx. 15 x 10(6) to 5.37 x 10(6) cells, and at 100 microM to 0.8 x 10(6) cells. A substantial inhibitory effect on cell proliferation could also be demonstrated with metronidazol (used clinically against amoebiasis). Under similar experimental conditions other tricyclic and phenothiazine derivatives (OFKs), designed originally to inhibit the trypanothione reductase of trypanosomatides, had an inhibitory effect of 16 to 95%. For comparison, similar results were obtained using clomipramine and a phenothiazine derivative (OFK006) with Trypanosoma cruzi and Crithidia luciliae, except that with the latter the inhibitory effect of clomipramine was less dramatic. Experiments comparing two E. histolytica strains showed that normal cell proliferation under anaerobiosis was higher in strain HK9 than in HM1, which is highly virulent, but that metronidazol and clomipramine were less effective against HM1. Two other drugs tested, diphenydramine (KD005) and a phenothiazine derivative (OFK008), also had significant but lower inhibitory effects on both strains. The inhibitory activity on cell proliferation and the lytic effects on this human parasite by the tricyclic

  13. Erythrophagocytosis in Entamoeba histolytica and Entamoeba dispar: a comparative study.

    Science.gov (United States)

    Talamás-Lara, Daniel; Chávez-Munguía, Bibiana; González-Robles, Arturo; Talamás-Rohana, Patricia; Salazar-Villatoro, Lizbeth; Durán-Díaz, Ángel; Martínez-Palomo, Adolfo

    2014-01-01

    Entamoeba histolytica is the causative agent of human intestinal and liver amebiasis. The extraordinary phagocytic activity of E. histolytica trophozoites has been accepted as one of the virulence mechanisms responsible for their invasive capacity. The recognition of the noninvasive Entamoeba dispar as a different species has raised the question as to whether the lack of pathogenic potential of this ameba correlates with a limited phagocytic capacity. We have therefore compared the process of erythrophagocytosis in both species by means of light and video microscopy, hemoglobin measurement, and the estimation of reactive oxygen species (ROS). In the present study, we confirmed that E. dispar has lower erythrophagocytic capacity. We also observed by video microscopy a new event of erythrocyte opsonization-like in both species, being more characteristic in E. histolytica. Moreover, E. dispar showed a lower capacity to produce ROS compared with the invasive species and also showed a large population of amoebae that did not engulf any erythrocyte over time. Our results demonstrate that E. histolytica has a higher phagocytic capacity than E. dispar, including a higher rate of production of ROS in the course of ingesting red blood cells.

  14. Erythrophagocytosis in Entamoeba histolytica and Entamoeba dispar: A Comparative Study

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    Daniel Talamás-Lara

    2014-01-01

    Full Text Available Entamoeba histolytica is the causative agent of human intestinal and liver amebiasis. The extraordinary phagocytic activity of E. histolytica trophozoites has been accepted as one of the virulence mechanisms responsible for their invasive capacity. The recognition of the noninvasive Entamoeba dispar as a different species has raised the question as to whether the lack of pathogenic potential of this ameba correlates with a limited phagocytic capacity. We have therefore compared the process of erythrophagocytosis in both species by means of light and video microscopy, hemoglobin measurement, and the estimation of reactive oxygen species (ROS. In the present study, we confirmed that E. dispar has lower erythrophagocytic capacity. We also observed by video microscopy a new event of erythrocyte opsonization-like in both species, being more characteristic in E. histolytica. Moreover, E. dispar showed a lower capacity to produce ROS compared with the invasive species and also showed a large population of amoebae that did not engulf any erythrocyte over time. Our results demonstrate that E. histolytica has a higher phagocytic capacity than E. dispar, including a higher rate of production of ROS in the course of ingesting red blood cells.

  15. Comparison of Routine Method with Antibody and Antigen Ones for Diagnosing Giardia-Entamoeba Histolytica in Stool and Blood

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    Gharavi, MJ. (PhD

    2015-01-01

    Full Text Available Background and Objectives: Giardia lamblia and Entamoeba histolytica are the most prevalent human intestinal pathogenic protozoa, worldwide. The clinical features of Giardia infection are acute diarrhea, a chronic condition with continuous diarrhea and malabsorption. Entamoeba histolytica invade intestinal tract without any typical clinical indications, and it can involve liver and other organs too. Therefore, we aimed to study these protozoa by serological and parasitological methods. Material and Methods: In this comparative study, the stool and blood specimens were collected from 1025 patients selected via simple random sampling in three different laboratories located in Tehran and Karaj, Iran (2012. Formalin Detergent test was performed on all samples. Both serum and stool positive samples of this method were analyzed for antigen and antibodies related to Giardia lamblia and Entamoeba histolytica, respectively. Results: of 1025 stool specimens, 76 (4.7% were positive for Giardia lamblia and 19 (1.8% for Entamoeba histolytica using Formalin-detergent method. In ELISA, 81 (7.9% coproantibodies to Giardia lamblia and 24 (2.3% coproantibodies to Entamoeba histolytica, 78 (7.6% corproantigen for Giardia lamblia, and 5 (0.4% for Entamoeba histolytica were observed. circulatory antibodies to Entamoeba histlytica were detected in 22 cases (2.1% Conclusion: Sensitivity of microscopic method compared to serological methods is higher than 90%; therefore, Formalin-detergent method can be the best method for stool examination.

  16. Genetic architecture of domestication-related traits in maize

    Science.gov (United States)

    Strong directional selection occurred during the domestication of maize from its wild ancestor teosinte, reducing its genetic diversity, particularly at genes controlling domestication-related traits. Nevertheless, variability for some domestication-related traits is maintained in maize. The genet...

  17. Development of a thermostabilized, one-step, nested, tetraplex PCR assay for simultaneous identification and differentiation of Entamoeba species, Entamoeba histolytica and Entamoeba dispar from stool samples.

    Science.gov (United States)

    Foo, Phiaw Chong; Chan, Yean Yean; See Too, Wei Cun; Tan, Zi Ning; Wong, Weng Kin; Lalitha, Pattabhiraman; Lim, Boon Huat

    2012-09-01

    Entamoeba histolytica is the only Entamoeba species that causes amoebiasis in humans. Approximately 50 million people are infected, with 100, 000 deaths annually in endemic countries. Molecular diagnosis of Entamoeba histolytica is important to differentiate it from the morphologically identical Entamoeba dispar to avoid unnecessary medication. Conventional molecular diagnostic tests require trained personnel, cold-chain transportation and/or are storage-dependent, which make them user-unfriendly. The aim of this study was to develop a thermostabilized, one-step, nested, tetraplex PCR assay for the detection of Entamoeba histolytica, Entamoeba dispar and Entamoeba species in cold-chain-free and ready-to-use form. The PCR test was designed based on the Entamoeba small subunit rRNA (SSU-rRNA) gene, which detects the presence of any Entamoeba species, and simultaneously can be used to differentiate Entamoeba histolytica from Entamoeba dispar. In addition, a pair of primers was designed to serve as an internal amplification control to help identify inhibitors in the samples. All PCR reagents together with the designed primers were thermostabilized by lyophilization and were stable at 24 °C for at least 6 months. The limit of detection of the tetraplex PCR was found to be 39 pg DNA or 1000 cells for Entamoeba histolytica and 78 pg DNA or 1000 cells for Entamoeba dispar, and the specificity was 100 %. In conclusion, this cold-chain-free, thermostabilized, one-step, nested, multiplex PCR assay was found to be efficacious in differentiating Entamoeba histolytica from other non-pathogenic Entamoeba species.

  18. Cell-matrix interactions of Entamoeba histolytica and E. dispar. A comparative study by electron-, atomic force- and confocal microscopy.

    Science.gov (United States)

    Talamás-Lara, Daniel; Talamás-Rohana, Patricia; Fragoso-Soriano, Rogelio Jaime; Espinosa-Cantellano, Martha; Chávez-Munguía, Bibiana; González-Robles, Arturo; Martínez-Palomo, Adolfo

    2015-10-01

    Invasion of tissues by Entamoeba histolytica is a multistep process that initiates with the adhesion of the parasite to target tissues. The recognition of the non-invasive Entamoeba dispar as a distinct, but closely related protozoan species raised the question as to whether the lack of its pathogenic potential could be related to a weaker adhesion due to limited cytoskeleton restructuring capacity. We here compared the adhesion process of both amebas to fibronectin through scanning, transmission, atomic force, and confocal microscopy. In addition, electrophoretic and western blot assays of actin were also compared. Adhesion of E. histolytica to fibronectin involves a dramatic reorganization of the actin network that results in a tighter contact to and the subsequent focal degradation of the fibronectin matrix. In contrast, E. dispar showed no regions of focal adhesion, the cytoskeleton was poorly reorganized and there was little fibronectin degradation. In addition, atomic force microscopy using topographic, error signal and phase modes revealed clear-cut differences at the site of contact of both amebas with the substrate. In spite of the morphological and genetic similarities between E. histolytica and E. dispar the present results demonstrate striking differences in their respective cell-to-matrix adhesion processes, which may be of relevance for understanding the invasive character of E. histolytica.

  19. Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Deiviane Aparecida Calegar

    2016-02-01

    Full Text Available This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR. The overall prevalence of infection was 22/213 (10.3%. The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

  20. Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil.

    Science.gov (United States)

    Calegar, Deiviane Aparecida; Nunes, Beatriz Coronato; Monteiro, Kerla Joeline Lima; Santos, Jéssica Pereira Dos; Toma, Helena Keiko; Gomes, Tais Ferreira; Lima, Marli Maria; Bóia, Márcio Neves; Carvalho-Costa, Filipe Anibal

    2016-02-01

    This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

  1. Uniqueness of Entamoeba sulfur metabolism: sulfolipid metabolism that plays pleiotropic roles in the parasitic life cycle.

    Science.gov (United States)

    Mi-Ichi, Fumika; Miyamoto, Tomofumi; Yoshida, Hiroki

    2017-09-07

    Sulfur metabolism is ubiquitous and terminally synthesizes various biomolecules that are crucial for organisms, such as sulfur-containing amino acids and co-factors, sulfolipids and sulfated saccharides. Entamoeba histolytica, a protozoan parasite responsible for amoebiasis, possesses the unique sulfur metabolism features of atypical localization and its terminal product being limited to sulfolipids. Here, we present an overall scheme of E. histolytica sulfur metabolism by relating all sulfotransferases and sulfatases to their substrates and products. Furthermore, a novel sulfur metabolite, fatty alcohol disulfates, was identified and shown to play an important role in trophozoite proliferation. Cholesteryl sulfate, another synthesized sulfolipid, was previously demonstrated to play an important role in encystation, a differentiation process from proliferative trophozoite to dormant cyst. Entamoeba survives by alternating between these two distinct forms; therefore, Entamoeba sulfur metabolism contributes to the parasitic life cycle via its terminal products. Interestingly, this unique feature of sulfur metabolism is not conserved in the nonparasitic close relative of Entamoeba, Mastigamoeba, because lateral gene transfer-mediated acquisition of sulfatases and sulfotransferases, critical enzymes conferring this feature, has only occurred in the Entamoeba lineage. Hence, our findings suggest that sulfolipid metabolism has a causal relationship with parasitism. © 2017 John Wiley & Sons Ltd.

  2. Salpingitis due to Entamoeba histolytica

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    Calore E.E

    2002-01-01

    Full Text Available We describe the pathology of a unique case of Fallopian tube amebiasis, associated with hydrosalpinx, in a 21-year-old woman. She complained of lower abdominal pain, had a foul-smelling green vaginal discharge and fever during one week. There was a discrete increase in body temperature and a painful abdominal palpation at the lower right side, with signs of local peritoneal irritation. Pathological examination showed a marked dilatation of the fallopian tube and hydrosalpinx. Microscopic examination showed a poorly formed granuloma composed of large macrophages with many Entamoeba histolytica trophozoites inside the fallopian tube. Even though it is a rare disease the correct diagnosis of female genital tract amebiasis is of great importance for the indication of proper therapy.

  3. Salpingitis due to Entamoeba histolytica

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    E.E Calore

    Full Text Available We describe the pathology of a unique case of Fallopian tube amebiasis, associated with hydrosalpinx, in a 21-year-old woman. She complained of lower abdominal pain, had a foul-smelling green vaginal discharge and fever during one week. There was a discrete increase in body temperature and a painful abdominal palpation at the lower right side, with signs of local peritoneal irritation. Pathological examination showed a marked dilatation of the fallopian tube and hydrosalpinx. Microscopic examination showed a poorly formed granuloma composed of large macrophages with many Entamoeba histolytica trophozoites inside the fallopian tube. Even though it is a rare disease the correct diagnosis of female genital tract amebiasis is of great importance for the indication of proper therapy.

  4. Uso da bioinformática na diferenciação molecular da Entamoeba histolytica e Entamoeba díspar - DOI: 10.4025/actascihealthsci.v30i2.2375 Molecular discrimination of Entamoeba histolytica and Entamoeba dispar by bioinformatics resources - DOI: 10.4025/actascihealthsci.v30i2.2375

    Directory of Open Access Journals (Sweden)

    Débora Sommer

    2008-12-01

    Full Text Available Amebíase invasiva, causada por Entamoeba histolytica, é microscopicamente indistinguível da espécie não-patogênica Entamoeba dispar. Com auxílio de ferramentas de bioinformática, objetivou-se diferenciar Entamoeba histolytica e Entamoeba dispar por técnicas moleculares. A análise foi realizada a partir do banco de dados da National Center for Biotechnology Information; pela pesquisa de similaridade de sequências, elegeu-se o gene da cisteína sintase. Um par de primer foi desenhado (programa Web Primer e foi selecionada a enzima de restrição TaqI (programa Web Cutter. Após a atuação da enzima, o fragmento foi dividido em dois, um com 255 pb e outro com 554 pb, padrão característico da E. histolytica. Na ausência de corte, o fragmento apresentou o tamanho de 809 pb, referente à E. dispar.Under microscopic conditions, the invasive Entamoeba histolytica is indistinguishable from the non-pathogenic species Entamoeba dispar. In this way, the present study was carried out to determine a molecular strategy for discriminating both species by the mechanisms of bioinformatics. The gene cysteine synthetase was considered for such a purpose by using the resources of the National Center for Biotechnology Information data bank in the search for similarities in the gene sequence. In this way, a primer pair was designed by the Web Primer program and the restriction enzyme TaqI was selected by the Web Cutter software program. The DNA fragment had a size of 809 bp before cutting, which is consistent with E. dispar. The gene fragment was partitioned in a first fragment with 255 bp and a second one with 554 bp, which is similar to the genetic characteristics of E. histolytica.

  5. 5 original article pcr detection of entamoeba histolytica

    African Journals Online (AJOL)

    boaz

    Department of Animal Production and Management, Busitema University ... method for the diagnosis of amoebiasis but could not differentiate between Entamoeba dispar/moshkovskii and Entamoeba ... In Mexico, E.histolytica prevalence of.

  6. Bioinformatic analysis of Entamoeba histolytica SINE1 elements

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    Butcher Sarah A

    2010-05-01

    Full Text Available Abstract Background Invasive amoebiasis, caused by infection with the human parasite Entamoeba histolytica remains a major cause of morbidity and mortality in some less-developed countries. Genetically E. histolytica exhibits a number of unusual features including having approximately 20% of its genome comprised of repetitive elements. These include a number of families of SINEs - non-autonomous elements which can, however, move with the help of partner LINEs. In many eukaryotes SINE mobility has had a profound effect on gene expression; in this study we concentrated on one such element - EhSINE1, looking in particular for evidence of recent transposition. Results EhSINE1s were detected in the newly reassembled E. histolytica genome by searching with a Hidden Markov Model developed to encapsulate the key features of this element; 393 were detected. Examination of their sequences revealed that some had an internal structure showing one to four 26-27 nt repeats. Members of the different classes differ in a number of ways and in particular those with two internal repeats show the properties expected of fairly recently transposed SINEs - they are the most homogeneous in length and sequence, they have the longest (i.e. the least decayed target site duplications and are the most likely to show evidence (in a cDNA library of active transcription. Furthermore we were able to identify 15 EhSINE1s (6 pairs and one triplet which appeared to be identical or very nearly so but inserted into different sites in the genome; these provide good evidence that if mobility has now ceased it has only done so very recently. Conclusions Of the many families of repetitive elements present in the genome of E. histolytica we have examined in detail just one - EhSINE1. We have shown that there is evidence for waves of transposition at different points in the past and no evidence that mobility has entirely ceased. There are many aspects of the biology of this parasite which

  7. Insights into Entamoeba histolytica virulence modulation.

    Science.gov (United States)

    Padilla-Vaca, F; Anaya-Velázquez, F

    2010-08-01

    Entamoeba histolytica is able to invade human tissues by means of several molecules and biological properties related to the virulence. Pathogenic amebas use three major virulence factors, Gal/GalNAc lectin, amebapore and proteases, for lyse, phagocytose, kill and destroy a variety of cells and tissues in the host. Responses of the parasite to host components such as mucins and bacterial flora influence the behavior of pathogenic amebas altering their expression of virulence factors. The relative virulence of different strains of E. histolytica has been shown to vary as a consequence of changes in conditions of in vitro cultivation which implies substantial changes in basic metabolic aspects and factors directly and indirectly related to amebic virulence. Comparison of E. histolytica strains with different virulence phenotypes and under different conditions of growth will help to identify new virulence factor candidates and define the interplay between virulence factors and invasive phenotype. Virulence attenuate mutants of E. histolytica are useful also to uncover novel virulence determinants. The comparison of biological properties and virulence factors between E. histolytica and E. dispar, a non-pathogenic species, has been a useful approach to investigate the key factors involved in the experimental presentation of amebiasis and its complex regulation. The molecular mechanisms that regulate these variations in virulence are not yet known. Their elucidation will help us to better understand the gene expression plasticity that enables the effective adaptation of the ameba to changes in growth culture conditions and host factors.

  8. Differential detection of Entamoeba histolytica from Entamoeba dispar by parasitological and nested multiplex polymerase chain reaction methods

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    esmaiel fallah

    2014-02-01

    Full Text Available Introduction: Amebiasis is an intestinal illness caused by a one-celled parasite (amoeba called Entamoeba (E histolytica. E histolytica and E dispar are morphologicallyundistinguishable but have genetic and functional differences. E. histolytica is invasive andcause amoebiasis, but E dispar cause an asymptomatic colonization which does not need to bemedically treated. We have performed a nested multiplex Polymerase Chain Reaction (PCRtargeting small subunit rRNA (Ribosomal ribonucleic acid gene for differential detection of Ehistolytica and E dispar directly from stool samples. Methods: All the fecal samples collected without preservation and were screened for amebiccells by parasitological methods. Fecal samples that containing amebic cells were stored at -20ºC until DNA extraction. DNA extraction was down by using a DNA extraction kit. Thegenus specific primers were designed using nucleotide sequences of 18S-rRNA gene ofEntamoeba. Results: Thirty one (4.28% stool samples out of 724 samples were positive for E histolytica/E dispar. The nested multiplex PCR illustrated that the size of diagnostic fragments of PCR products was obviously different for two Entamoeba species, the specific product size for Ehistolytica and E dispar was 439 and 174 bp. The nested multiplex PCR was positive in 25 outof 31 stool specimens that 17 (54.8% samples were positive for E dispar and 8 (25.8%samples were positive for E histolytica. Conclusion: Nested multiplex PCR was useful for the specific detection of E histolytica and Edispar in stool samples. In current study we detected that E dispar was more prevalent in our study area.

  9. Differentiating Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii using nested polymerase chain reaction (PCR) in rural communities in Malaysia.

    Science.gov (United States)

    Ngui, Romano; Angal, Lorainne; Fakhrurrazi, Siti Aminah; Lian, Yvonne Lim Ai; Ling, Lau Yee; Ibrahim, Jamaiah; Mahmud, Rohela

    2012-09-04

    In this study, a total of 426 human faecal samples were examined for the presence of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii infection via a combination of microscopic examination and nested polymerase chain reaction (PCR) targeting 16S ribosomal RNA of Entamoeba species. Faecal sample were collected from 426 participants in five rural villages in Peninsular Malaysia. The faecal samples were processed by direct wet smear and formalin ethyl acetate concentration technique followed by iodine staining and examined via microscopy for the presence of Entamoeba species and other intestinal parasites. Microscopically positive samples for Entamoeba species cysts were further characterized using a Nested Polymerase Chain Reaction (Nested-PCR) targeting 16S-like ribosomal RNA gene. The data entry and analysis was carried out using the SPSS software (Statistical Package for the Social Sciences) program for Windows version 17 (SPSS, Chicago, IL, USA). Based on single faecal examination, overall prevalence of Entamoeba infection was 17.6% (75/426). Females (19.1%) were more commonly infected compared to males (15.9%). Comparison by age groups showed that adults (23.9%) had higher infection rates than children (15.3%). The PCR results showed that 52 out of 75 microscopy positive samples successfully generated species-specific amplicons. The infection with E. histolytica (75.0%; 39/52) was the most common, followed by E. dispar (30.8%; 18/52) and E. moshkovskii (5.8%; 3/52). Of these, 33 (63.5%) were shown to contain only E. histolytica, 10 (19.2%) contained E. dispar and 3 (5.8%) contained only E. moshkovskii. Mixed infection with E. histolytica and E. dispar was found in 6 (11.5%) samples. The present study essentially emphasized the benefit of molecular techniques in discriminating the pathogenic Entamoeba species from the non-pathogenic for accurate diagnosis and better management of amoebiasis. The presence of E. moshkovskii is of great public health

  10. Entamoeba histolytica: oxygen resistance and virulence.

    Science.gov (United States)

    Ramos-Martínez, Espiridión; Olivos-García, Alfonso; Saavedra, Emma; Nequiz, Mario; Sánchez, Ernesto C; Tello, Eusebio; El-Hafidi, Mohamed; Saralegui, Andrés; Pineda, Erika; Delgado, José; Montfort, Irmgard; Pérez-Tamayo, Ruy

    2009-05-01

    Entamoeba histolytica virulence has been attributed to several amoebic molecules such as adhesins, amoebapores and cysteine proteinases, but supporting evidence is either partial or indirect. In this work we compared several in vitro and in vivo features of both virulent E. histolytica (vEh) and non-virulent E. histolytica (nvEh) axenic HM-1 IMSS strains, such as complement resistance, proteinase activity, haemolytic, phagocytic and cytotoxic capacities, survival in mice caecum, and susceptibility to O(2). The only difference observed was a higher in vitro susceptibility of nvEh to O(2). The molecular mechanism of that difference was analyzed in both groups of amoebae after high O(2) exposure. vEh O(2) resistance correlated with: (i) higher O(2) reduction (O(2)(-) and H(2)O(2) production); (ii) increased H(2)O(2) resistance and thiol peroxidase activity, and (iii) reversible pyruvate: ferredoxin oxidoreductase (PFOR) inhibition. Despite the high level of carbonylated proteins in nvEh after O(2) exposure, membrane oxidation by reactive oxygen species was not observed. These results suggest that the virulent phenotype of E. histolytica is related to the greater ability to reduce O(2) and H(2)O(2) as well as PFOR reactivation, whereas nvEh undergoes irreversible PFOR inhibition resulting in metabolic failure and amoebic death.

  11. Susceptibility testing of Entamoeba histolytica

    Energy Technology Data Exchange (ETDEWEB)

    Cedeno, J.R.; Krogstad, D.J.

    1983-12-01

    The growth of Entamoeba histolytica in microtiter plates in vitro in a variety of environments with reduced oxygen tensions is reported. With 3% O/sub 2/, 3% CO/sub 2/, and 94% N/sub 2/, the parasite growth in microtiter plates was identical to that in screw-capped culture tubes, as measured by (/sup 3/H)thymidine incorporation and by quantitative parasite counts. There were no significant differences between the drug concentrations necessary to inhibit parasite growth by 50% based on (/sup 3/H)thymidine incorporation vs those defined by quantitative parasite counts for the 15 antimicrobial agents tested (including seven drugs used for the treatment of amebiasis). This technique provides a reproducible method to quantitate the activity of potential antiamebic agents in vitro. The isotopic method should be of particular value in defining the metabolism of the parasite and effects of antimicrobial agents on it, whereas the morphologic method may be more valuable for workers with limited resources available to them.

  12. Primary pathogenicity analysis of a Chinese Entamoeba histolytica isolate.

    Science.gov (United States)

    Luo, Muxia; Feng, Meng; Min, Xiangyang; Li, Xueping; Cai, Junlong; Tachibana, Hiroshi; Cheng, Xunjia

    2013-04-01

    This study is the first to isolate an Entamoeba histolytica strain from Chinese amoebic patients and to conduct a detailed examination of its virulence. A fecal sample that contains cysts of E. histolytica was obtained from Guangxi province. The sample was cultured axenically and then cloned by limiting dilution, and named as XLAC. In vitro and in vivo tests were conducted to evaluate the virulence of the Entamoeba isolate. The E. histolytica strain XLAC was successfully cloned and cultured axenically. DNA regions that contain hexokinase, glucose-6-phosphate isomerase, phosphoglucomutase, and heavy subunit of lectin genes were amplified by PCR. The PCR products were then sequenced. Virulence analysis suggested that the XLAC strain was similar to the HM1:IMSS strain at the genetic level. In vitro and in vivo tests also implicated these strains to be similar. These findings may be attributed to the low expression levels of pathogenic genes obtained through realtime PCR. The XLAC strain restored its virulence after it was injected into hamster liver. This study may be a good model for studying virulence changes in E. histolytica.

  13. Comparative analysis of genotypic diversity in Entamoeba nuttalli isolates from Tibetan macaques and rhesus macaques in China.

    Science.gov (United States)

    Guan, Yue; Feng, Meng; Cai, Junlong; Min, Xiangyang; Zhou, Xingyu; Xu, Qing; Tan, Ning; Cheng, Xunjia; Tachibana, Hiroshi

    2016-03-01

    We have recently demonstrated the potentially virulent species Entamoeba nuttalli as one of the highly prevalent parasites in rhesus macaques (Macaca mulatta) in Mount Long-hu and Gui-yang in China. Tibetan macaque (Macaca thibetana) is a unique species living in China. To evaluate the prevalence of Entamoeba species in wild Tibetan macaques, we obtained 89 stool samples in Mount E-mei of Si-chuan Province in China. PCR analysis detected E. nuttalli, Entamoeba coli, and Entamoeba polecki ST2 in 17%, 42%, and 66% of the samples, respectively, whereas Entamoeba histolytica and Entamoeba dispar were undetected. This study is the first to report on the detection of E. nuttalli from Tibetan macaques. Six E. nuttalli isolates were obtained, 18S rRNA gene and six tRNA-linked short tandem repeat (STR) loci of the isolates were sequenced. The Mantel test results gave an r value of 0.97 of relationships between geographical distance and genetic diversity of Chinese E. nuttalli populations, indicating a significant isolation-by-distance effect in Chinese E. nuttalli according to the tRNA-STR loci sequences. Structural analysis of E. nuttalli isolates based on tRNA-linked STR loci demonstrated three Chinese E. nuttalli populations with their respective features, but the Gui-yang population was located in the middle. In the distance-based NJ tree, E. nuttalli isolates were divided into five different branches, and E-mei isolates were attributed to an independent branch to distinguish them from Gui-yang and Long-hu isolates. Genetic analysis in this study provided clues of the genetic differences between E. nuttalli isolates from Tibetan macaques and rhesus macaques in China.

  14. Prevalence of Entamoeba histolytica/Entamoeba dispar in the city of Campina Grande, in northeastern Brazil.

    Science.gov (United States)

    Silva, Maria Teresa Nascimento; Santana, José Valfrido; Bragagnoli, Gérson; Marinho, Alexandre Magno da Nóbrega; Malagueño, Elizabeth

    2014-01-01

    There is a clear need to perform epidemiological studies to find the true prevalence of Entamoeba histolytica around the world. The evaluation of this prevalence has been hindered by the existence of two different species which are morphologically identical, but genetically different, namely E. histolytica, which causes amebiasis, and E. dispar, which is non-pathogenic. In Brazil, the E. dispar has been detected in communities in the Southeastern (SE) and Northeastern (NE) regions with poor sanitation. However, individuals infected with E. histolytica have been identified in other regions. There is an absence of reports on the prevalence of these parasites in the state of Paraíba, which also has areas with poor sanitary conditions where a high prevalence of the E. histolytica/E. dispar complex has been detected in children from urban slums. The present study evaluated the prevalence of E. histolytica and E. dispar in 1,195 asymptomatic children between two and 10 years of age, living in a sprawling urban slum in Campina Grande, in the state of Paraíba, in Northeastern Brazil. These children were examined and their feces samples were analyzed microscopically. A total of 553 children tested positive for the E. histolytica/E. dispar complex, and 456 of the positive samples were tested with the E. histolytica II® ELISA kit. All 456 samples were negative for the presence of the adhesin E. histolytica specific antigen. The evidence suggests that in this community E. histolytica is absent and E. dispar is the dominant species.

  15. [Amebiasis: implications of the recognition of Entamoeba dispar and the identification of Entamoeba moshkovskii in humans].

    Science.gov (United States)

    Chacín-Bonilla, Leonor

    2010-06-01

    The history of Entamoeba histolytica is very confuse and shows several wrong concepts about the parasite and its relationship with the host. The poor correlation between the prevalence of asymptomatic and symptomatic amebiasis originated the proposal of three explicative hypothesis, among them was the concept of Brumpt that E. histolytica comprised two morphologically identical species, E. dysenteriae and E. dispar. The application of modern molecular techniques irrefutably proved that E. histolytica was really a complex of two species, confirming the concept of Brumpt almost 7 decades later. Recent studies have identified in humans E. moshkovskii, morphologically indistinguishable from E. histolytica and E. dispar, a great genetic diversity within each of these species, and heterogeneity in virulence among E. histolytica strains. The redescription of E. dispar, and the recovery of E. moshkovskii from humans have had a major impact in our understanding of E. histolytica and amebiasis with important clinical and epidemiologic implications. This has led to the need of a reevaluation of the infection in terms of prevalence and morbidity in the global population and to study the geographic distribution, prevalence, and transmission pattern of E. histolytica strains in order to detect those with epidemiologic relevance and predict the risk of amebic disease in a population.

  16. Genetics of intracranial aneurysms and related diseases

    NARCIS (Netherlands)

    van 't Hof, F.N.G.

    2017-01-01

    Intracranial aneurysms (IA) are dilatations of the vessel walls of cerebral arteries. Some can rupture and result in a subarachnoid hemorrhage (SAH), a severe subtype of stroke. This thesis is set out to elucidate the pathophysiology of IA from a genetic perspective. The main conclusions are: 1.

  17. Genetics of metabolic syndrome and related traits

    NARCIS (Netherlands)

    Henneman, Peter

    2010-01-01

    In this thesis several aspects of metabolic syndrome are addressed. The focus involves questions concerning the genetics of obesity, TG and cholesterol and hyperglycemia. Since we hypothesized that obesity is the most important trigger of metabolic impairment, the MetS definition in this thesis was

  18. Proteomic comparison of Entamoeba histolytica and Entamoeba dispar and the role of E. histolytica alcohol dehydrogenase 3 in virulence.

    Directory of Open Access Journals (Sweden)

    Paul H Davis

    Full Text Available The protozoan intestinal parasite Entamoeba histolytica infects millions of people worldwide and is capable of causing amebic dysentery and amebic liver abscess. The closely related species Entamoeba dispar colonizes many more individuals, but this organism does not induce disease. To identify molecular differences between these two organisms that may account for their differential ability to cause disease in humans, we used two-dimensional gel-based (DIGE proteomic analysis to compare whole cell lysates of E. histolytica and E. dispar. We observed 141 spots expressed at a substantially (>5-fold higher level in E. histolytica HM-1:IMSS than E. dispar and 189 spots showing the opposite pattern. Strikingly, 3 of 4 proteins consistently identified as different at a greater than 5-fold level between E. histolytica HM-1:IMSS and E. dispar were identical to proteins recently identified as differentially expressed between E. histolytica HM-1:IMSS and the reduced virulence strain E. histolytica Rahman. One of these was E. histolytica alcohol dehydrogenase 3 (EhADH3. We found that E. histolytica possesses a higher level of NADP-dependent alcohol dehydrogenase activity than E. dispar and that some EhADH3 can be localized to the surface of E. histolytica. Episomal overexpression of EhADH3 in E. histolytica trophozoites resulted in only subtle phenotypic differences in E. histolytica virulence in animal models of amebic colitis and amebic liver abscess, making it difficult to directly link EhADH3 levels to virulence differences between E. histolytica and less-pathogenic Entamoeba.

  19. Real-time PCR assay in differentiating Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii infections in Orang Asli settlements in Malaysia.

    Science.gov (United States)

    Lau, Yee Ling; Anthony, Claudia; Fakhrurrazi, Siti Aminah; Ibrahim, Jamaiah; Ithoi, Init; Mahmud, Rohela

    2013-08-28

    Amebiasis caused by Entamoeba histolytica is the third leading cause of death worldwide. This pathogenic amoeba is morphologically indistinguishable from E. dispar and E. moshkovskii, the non-pathogenic species. Polymerase chain reaction is the current method of choice approved by World Health Organization. Real-time PCR is another attractive molecular method for diagnosis of infectious diseases as post-PCR analyses are eliminated and turnaround times are shorter. The present work aimed to compare the results of Entamoeba species identification using the real-time assay against the established nested PCR method. In this study, a total of 334 human faecal samples were collected from different Orang Asli settlements. Faecal samples were processed by direct wet smear and formalin ethyl acetate concentration methods followed by iodine staining and was microscopically examined for Entamoeba species and other intestinal parasites. Microscopically positive samples were then subject to nested PCR and real-time PCR. The overall prevalence of Entamoeba infection was 19.5% (65/334). SK Posh Piah recorded highest Entamoeba prevalence (63.3%) while Kampung Kemensah had the lowest prevalence (3.7%) of Entamoeba. Microscopically positive samples were then tested by real-time PCR and nested PCR for the presence of Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii infection. Real-time PCR showed higher Entamoeba detection (86.2%) compared to nested PCR (80%), although the McNemar test value showed no significant difference between the two methods (p = 0.221). This study is the first in Malaysia to report the use of real-time PCR in identifying and differentiating the three Entamoeba infections. It is also proven to be more effective compared to the conventional nested PCR molecular method.

  20. Genetics of metabolic syndrome and related traits

    OpenAIRE

    Henneman, Peter

    2010-01-01

    In this thesis several aspects of metabolic syndrome are addressed. The focus involves questions concerning the genetics of obesity, TG and cholesterol and hyperglycemia. Since we hypothesized that obesity is the most important trigger of metabolic impairment, the MetS definition in this thesis was chosen to include the obesity measure waist circumference as an essential component. In the study described in chapter 2, the heritability of the metabolic syndrome was addressed and compared to th...

  1. Investigating amoebic pathogenesis using Entamoeba histolytica DNA microarrays

    Indian Academy of Sciences (India)

    Upinder Singh; Preetam Shah

    2002-11-01

    Entamoeba histolytica, a protozoan parasite, causes diarrhea and liver abscesses resulting in 50 million cases of infection worldwide annually. Elucidation of parasite virulence determinants has recently been investigated using genetic approaches. We have undertaken a genomics approach to identify novel virulence determinants in the parasite. A DNA microarray of E. histolytica is being developed based on sequenced genomic clones from the genome sequencing efforts of The Institute of Genomic Research (TIGR) and the Sanger Center. Hybridization of the slides with samples labelled differentially using fluorescent dyes allows the characterization of transcriptional profiles of genes under the biological conditions tested. Additionally, a genome-wide comparison of E. histolytica and E. dispar can be undertaken. The development of an E. histolytica microarray will be outlined and its uses in identifying novel virulence determinants and characterizing amoebic biology will be discussed.

  2. Entamoeba mitosomes play an important role in encystation by association with cholesteryl sulfate synthesis.

    Science.gov (United States)

    Mi-ichi, Fumika; Miyamoto, Tomofumi; Takao, Shouko; Jeelani, Ghulam; Hashimoto, Tetsuo; Hara, Hiromitsu; Nozaki, Tomoyoshi; Yoshida, Hiroki

    2015-06-01

    Hydrogenosomes and mitosomes are mitochondrion-related organelles (MROs) that have highly reduced and divergent functions in anaerobic/microaerophilic eukaryotes. Entamoeba histolytica, a microaerophilic, parasitic amoebozoan species, which causes intestinal and extraintestinal amoebiasis in humans, possesses mitosomes, the existence and biological functions of which have been a longstanding enigma in the evolution of mitochondria. We previously demonstrated that sulfate activation, which is not generally compartmentalized to mitochondria, is a major function of E. histolytica mitosomes. However, because the final metabolites of sulfate activation remain unknown, the overall scheme of this metabolism and the role of mitosomes in Entamoeba have not been elucidated. In this study we purified and identified cholesteryl sulfate (CS) as a final metabolite of sulfate activation. We then identified the gene encoding the cholesteryl sulfotransferase responsible for synthesizing CS. Addition of CS to culture media increased the number of cysts, the dormant form that differentiates from proliferative trophozoites. Conversely, chlorate, a selective inhibitor of the first enzyme in the sulfate-activation pathway, inhibited cyst formation in a dose-dependent manner. These results indicate that CS plays an important role in differentiation, an essential process for the transmission of Entamoeba between hosts. Furthermore, we show that Mastigamoeba balamuthi, an anaerobic, free-living amoebozoan species, which is a close relative of E. histolytica, also has the sulfate-activation pathway in MROs but does not possess the capacity for CS production. Hence, we propose that a unique function of MROs in Entamoeba contributes to its adaptation to its parasitic life cycle.

  3. Genetic diversity in aspen and its relation to arthropod abundance.

    Science.gov (United States)

    Zhang, Chunxia; Vornam, Barbara; Volmer, Katharina; Prinz, Kathleen; Kleemann, Frauke; Köhler, Lars; Polle, Andrea; Finkeldey, Reiner

    2014-01-01

    The ecological consequences of biodiversity have become a prominent public issue. Little is known on the effect of genetic diversity on ecosystem services. Here, a diversity experiment was established with European and North American aspen (Populus tremula, P. tremuloides) planted in plots representing either a single deme only or combinations of two, four and eight demes. The goals of this study were to explore the complex inter- and intraspecific genetic diversity of aspen and to then relate three measures for diversity (deme diversity, genetic diversity determined as Shannon index or as expected heterozygosity) to arthropod abundance. Microsatellite and AFLP markers were used to analyze the genetic variation patterns within and between the aspen demes and deme mixtures. Large differences were observed regarding the genetic diversity within demes. An analysis of molecular variance revealed that most of the total genetic diversity was found within demes, but the genetic differentiation among demes was also high. The complex patterns of genetic diversity and differentiation resulted in large differences of the genetic variation within plots. The average diversity increased from plots with only one deme to plots with two, four, and eight demes, respectively and separated plots with and without American aspen. To test whether intra- and interspecific diversity impacts on ecosystem services, arthropod abundance was determined. Increasing genetic diversity of aspen was related to increasing abundance of arthropods. However, the relationship was mainly driven by the presence of American aspen suggesting that species identity overrode the effect of intraspecific variation of European aspen.

  4. Proteomic analysis of Entamoeba histolytica in vivo assembled pre-mRNA splicing complexes.

    Science.gov (United States)

    Valdés, Jesús; Nozaki, Tomoyoshi; Sato, Emi; Chiba, Yoko; Nakada-Tsukui, Kumiko; Villegas-Sepúlveda, Nicolás; Winkler, Robert; Azuara-Liceaga, Elisa; Mendoza-Figueroa, María Saraí; Watanabe, Natsuki; Santos, Herbert J; Saito-Nakano, Yumiko; Galindo-Rosales, José Manuel

    2014-12-05

    The genome of the human intestinal parasite Entamoeba histolytica contains nearly 3000 introns and bioinformatic predictions indicate that major and minor spliceosomes occur in Entamoeba. However, except for the U2-, U4-, U5- and U6 snRNAs, no other splicing factor has been cloned and characterized. Here, we HA-tagged cloned the snRNP component U1A and assessed its expression and nuclear localization. Because the snRNP-free U1A form interacts with polyadenylate-binding protein, HA-U1A immunoprecipitates could identify early and late splicing complexes. Avoiding Entamoeba's endonucleases and ensuring the precipitation of RNA-binding proteins, parasite cultures were UV cross-linked prior to nuclear fraction immunoprecipitations with HA antibodies, and precipitates were subjected to tandem mass spectrometry (MS/MS) analyses. To discriminate their nuclear roles (chromatin-, co-transcriptional-, splicing-related), MS/MS analyses were carried out with proteins eluted with MS2-GST-sepharose from nuclear extracts of an MS2 aptamer-tagged Rabx13 intron amoeba transformant. Thus, we probed thirty-six Entamoeba proteins corresponding to 32 cognate splicing-specific factors, including 13 DExH/D helicases required for all stages of splicing, and 12 different splicing-related helicases were identified also. Furthermore 50 additional proteins, possibly involved in co-transcriptional processes were identified, revealing the complexity of co-transcriptional splicing in Entamoeba. Some of these later factors were not previously found in splicing complex analyses. Numerous facts about the splicing of the nearly 3000 introns of the Entamoeba genome have not been unraveled, particularly the splicing factors and their activities. Considering that many of such introns are located in metabolic genes, the knowledge of the splicing cues has the potential to be used to attack or control the parasite. We have found numerous new splicing-related factors which could have therapeutic benefit. We

  5. Expanding the Entamoeba Universe: New Hosts Yield Novel Ribosomal Lineages.

    Science.gov (United States)

    Jacob, Alison S; Busby, Eloise J; Levy, Abigail D; Komm, Natasha; Clark, C Graham

    2016-01-01

    Removing the requirement for cell culture has led to a substantial increase in the number of lineages of Entamoeba recognized as distinct. Surveying the range of potential host species for this parasite genus has barely been started and it is clear that additional sampling of the same host in different locations often identifies additional diversity. In this study, using small subunit ribosomal RNA gene sequencing, we identify four new lineages of Entamoeba, including the first report of Entamoeba from an elephant, and extend the host range of some previously described lineages. In addition, examination of microbiome data from a number of host animals suggests that substantial Entamoeba diversity remains to be uncovered.

  6. Cell-matrix interactions of Entamoeba histolytica and E. dispar. A comparative study by electron-, atomic force- and confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Talamás-Lara, Daniel, E-mail: daniel_talamas@hotmail.com [Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico); Talamás-Rohana, Patricia, E-mail: ptr@cinvestav.mx [Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico); Fragoso-Soriano, Rogelio Jaime, E-mail: rogelio@fis.cinvestav.mx [Department of Physics, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico); Espinosa-Cantellano, Martha, E-mail: mespinosac@cinvestav.mx [Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico); Chávez-Munguía, Bibiana, E-mail: bchavez@cinvestav.mx [Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico); González-Robles, Arturo, E-mail: goroa@cinvestav.mx [Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico); Martínez-Palomo, Adolfo, E-mail: amartine@cinvestav.mx [Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados, Apartado Postal 14-740, Mexico City (Mexico)

    2015-10-01

    Invasion of tissues by Entamoeba histolytica is a multistep process that initiates with the adhesion of the parasite to target tissues. The recognition of the non-invasive Entamoeba dispar as a distinct, but closely related protozoan species raised the question as to whether the lack of its pathogenic potential could be related to a weaker adhesion due to limited cytoskeleton restructuring capacity. We here compared the adhesion process of both amebas to fibronectin through scanning, transmission, atomic force, and confocal microscopy. In addition, electrophoretic and western blot assays of actin were also compared. Adhesion of E. histolytica to fibronectin involves a dramatic reorganization of the actin network that results in a tighter contact to and the subsequent focal degradation of the fibronectin matrix. In contrast, E. dispar showed no regions of focal adhesion, the cytoskeleton was poorly reorganized and there was little fibronectin degradation. In addition, atomic force microscopy using topographic, error signal and phase modes revealed clear-cut differences at the site of contact of both amebas with the substrate. In spite of the morphological and genetic similarities between E. histolytica and E. dispar the present results demonstrate striking differences in their respective cell-to-matrix adhesion processes, which may be of relevance for understanding the invasive character of E. histolytica. - Highlights: • Striking differences in adhesion to FN between E. histolytica and E. dispar. • A greater degree of cell stiffness in E. histolytica with respect to E. dispar. • E. histolytica but not E. dispar forms regions of close contact with FN. • The actin cytoskeleton is involved in the pathogenicity of E. histolytica.

  7. Gene migration for re-emerging amebiasis in Iran's northwest-Iraq borders: a microevolutionary scale for reflecting epidemiological drift of Entamoeba histolytica metapopulations.

    Science.gov (United States)

    Mohammadzadeh, Asad; Spotin, Adel; Mahami-Oskouei, Mahmoud; Haghighi, Ali; Zebardast, Nozhat; Kohansal, Kobra

    2017-01-01

    In the microevolutionary scales of Entamoeba isolates, the gene migration shows how Entamoeba spp. has epidemiologically drifted among border countries. Five hundred fecal samples were taken from patients suffering gastrointestinal disorders, abdominal pain, and diarrhea at Saggez, northwest Iran located within the border Iraq country. Following parasitological techniques, DNA samples were extracted and amplified by polymerase chain reaction (PCR) of 18S rRNA region to identify Entamoeba infections. To distinguish the Entamoeba spp., a multiplex PCR was conducted. Amplicons were sequenced to reconfirm their heterogeneity traits and phylogenetic analysis. Additionally, Entamoeba histolytica sequences of Iraq were retrieved from GenBank database. The suspected isolates were diagnosed as E. histolytica (2.2 %), Entamoeba moshkovskii (1 %), and Entamoeba dispar (0.4 %). Mixed Entamoeba infections did not detect among isolates. A parsimonious network of the sequence haplotypes displayed star-like features in the overall isolates containing E.h1, E.d2, and E.m3 as the most common haplotypes. According to analysis of molecular variance (AMOVA) test, high partial value of haplotype diversity (0.700 to 0.800) of E. histolytica was shown the total genetic variability within populations while nucleotide diversity was low among Iranian and Iraqi metapopulations. Neutrality indices of the 18S rRNA were shown negative values in E. histolytica populations which indicating significant deviations from neutrality. A pairwise fixation index (F-statistics [Fst]) as a degree of gene flow had a low value for all populations (0.001) while the number of migrants was 2.48. The statistically Fst value indicates that E. histolytica isolates are not genetically differentiated among shared isolates of Iran and Iraq. Occurrence of E.h1 between two regional populations indicates that there is dawn of Entamoeba flow due to transfer of alleles from one population to another population through

  8. PREVALENCE OF Entamoeba histolytica/Entamoeba dispar IN THE CITY OF CAMPINA GRANDE, IN NORTHEASTERN BRAZIL

    Directory of Open Access Journals (Sweden)

    Maria Teresa Nascimento Silva

    2014-09-01

    Full Text Available There is a clear need to perform epidemiological studies to find the true prevalence of Entamoeba histolytica around the world. The evaluation of this prevalence has been hindered by the existence of two different species which are morphologically identical, but genetically different, namely E. histolytica, which causes amebiasis, and E. dispar, which is non-pathogenic. In Brazil, the E. dispar has been detected in communities in the Southeastern (SE and Northeastern (NE regions with poor sanitation. However, individuals infected with E. histolytica have been identified in other regions. There is an absence of reports on the prevalence of these parasites in the state of Paraíba, which also has areas with poor sanitary conditions where a high prevalence of the E. histolytica/E. dispar complex has been detected in children from urban slums. The present study evaluated the prevalence of E. histolytica and E. dispar in 1,195 asymptomatic children between two and 10 years of age, living in a sprawling urban slum in Campina Grande, in the state of Paraíba, in Northeastern Brazil. These children were examined and their feces samples were analyzed microscopically. A total of 553 children tested positive for the E. histolytica/E. dispar complex, and 456 of the positive samples were tested with the E. histolytica II® ELISA kit. All 456 samples were negative for the presence of the adhesin E. histolytica specific antigen. The evidence suggests that in this community E. histolytica is absent and E. dispar is the dominant species.

  9. Genetics Home Reference: MYH9-related disorder

    Science.gov (United States)

    ... They Important? Merck Manual Consumer Version: Glomerulonephritis Merck Manual Consumer Version: Thrombocytopenia Orphanet: MYH9-related disease Patient Support and Advocacy Resources (3 links) National Kidney Foundation National Organization for Rare Disorders (NORD): May Hegglin Anomaly University ...

  10. Entamoeba invadens, encystation process and enolase.

    Science.gov (United States)

    Segovia-Gamboa, Norma Cristina; Chávez-Munguía, Bibiana; Medina-Flores, Yolanda; Cázares-Raga, Febe Elena; Hernández-Ramírez, Verónica Ivonne; Martínez-Palomo, Adolfo; Talamás-Rohana, Patricia

    2010-06-01

    The reptilian parasite Entamoeba invadens is accepted as a model for the study of the Entamoeba encystation process. Here we describe the production and characterization of a mAb (B4F2), generated against a component of the E. invadens cyst wall. This mAb specifically recognizes a 48-kDa protein present in cytoplasmic vesicles of cells encysting for 24 h. In mature cysts (96 h), the antigen was detected on the cyst surface. By two-dimensional electrophoresis and mass spectrometry analysis, the B4F2 specific antigen was identified as enolase. Levels of enolase mRNA were increased in encysting cells and the B4F2 mAb was found to inhibit cyst formation. Therefore, these results strongly suggest a new role for enolase in E. invadens encystation, and the B4F2 mAb will be useful tool to study its role in the differentiation process.

  11. Entamoeba spp. diagnosis in patients with inflmmatory diarrhea by staining, copro-antigen ELISA and multiplex PCR methods

    Directory of Open Access Journals (Sweden)

    Zahra Gharibi

    2017-10-01

    Full Text Available Objective: To evaluate Entamoeba spp. diagnosis in patients with inflammatory diarrhea by staining, copro-antigen ELISA and multiplex PCR methods. Methods: In this descriptive cross-sectional survey, 200 stool samples were randomly collected during 2015–2016. The stool samples were evaluated microscopically for the presence of the parasite using direct and formalin-ether concentration and trichrome staining methods. Then, the stool samples were examined by copro-antigen ELISA (Biomerica Company and multiplex PCR methods. Results: Of 200 samples, 17, 29 and 23 cases were positive for Entamoeba species by the staining, copro-antigen ELISA and multiplex PCR methods, respectively. Of 23 positive samples in multiplex PCR test, 13 and 10 samples were positive for Entamoeba dispar (E. dispar and Entamoeba histolytica (E. histolytica, respectively. Conclusions: Our finding indicated a relatively high prevalence of Entamoeba species in patients with inflammatory diarrhea in Ahvaz city. Due to the complications of E. histolytica/ dispar infection, the health authorities of the city must pay more attention to control and prevent the transmission of E. histolytica/dispar to individuals.

  12. [History of the Entamoeba histolytica protozoan].

    Science.gov (United States)

    Pinilla, Análida Elizabeth; López, Myriam Consuelo; Viasus, Diego Fernando

    2008-01-01

    This article presents a history of Entamoeba histolytica spanning since the remote times when it was not even recognized as a cause of human disease to the recent molecular advances. Feder Losch (1875) in Saint Petersburg, found amoebae in fecal samples but only regarded them as responsible for maintaining the inflammatory process, not as a cause of dysentery. Fritz Schaudinn (1903) established the differentiation between Entamoeba histolytica and Endamoeba coli, Schaudinn decided to call it E. histolytica because of its ability to cause tissue lysis. Emile Brumpt (1925) based on experimental studies, pointed out the existence of E. Histolytica as a species complex, comprising two morphologically indistinguishable species, E. dysenteríae which is the cause of symptomatic infection, and Entamoeba dispar found only in asymptomatic carriers. Louis Diamond et al (1961) during the 1960s developed an axenic culture medium for E. histolytica which allowed in vivo and in vitro studies. Sargeaunt and Williams (1978) distinguished for the first time E. histolytica strains by isoenzyme electrophoresis, thus confirming that E. hystolytica was indeed a species complex comprising both pathogenic and non-pathogenic species. William Petri et al (1987 demonstrated that the 170 kDa protein with greater antigenicity was the Gal/GalNac-specific lectin. Diamond and Clark (1993) described again Brumpt's original 1925 hypothesis, concluding that there was enough evidence to support the existence of two morphologically indistinguishable species, a pathogenic and a nonpathogenic one, corresponding to E. histolytica and Entamoeba dispar respectively. The World Health Organization accepted this hypothesis in 1997.

  13. Gene discovery in the Entamoeba invadens genome.

    Science.gov (United States)

    Wang, Zheng; Samuelson, John; Clark, C Graham; Eichinger, Daniel; Paul, Jaishree; Van Dellen, Katrina; Hall, Neil; Anderson, Iain; Loftus, Brendan

    2003-06-01

    Entamoeba invadens, a parasite of reptiles, is a model for the study of encystation by the human enteric pathogen Entamoeba histolytica, because E. invadens form cysts in axenic culture. With approximately 0.5-fold sequence coverage of the genome, we were able to get insights into E. invadens gene and genome features. Overall, the E. invadens genome displays many of the features that are emerging from ongoing genome sequencing efforts in E. histolytica. At the nucleotide level the E. invadens genome has on average 60% sequence identity with that of E. histolytica. The presence of introns in E. invadens was predicted with similar consensus (GTTTGT em leader A/TAG) sequences to those identified in E. histolytica and Entamoeba dispar. Sequences highly repeated in the genome of E. histolytica (rRNAs, tRNAs, CXXC-rich proteins, and Leu-rich repeat proteins) were found to be highly repeated in the E. invadens genome. Numerous proteins homologous to those implicated in amoebic virulence, (Gal/GalNAc lectins, amoebapores, and cysteine proteinases) and drug resistance (p-glycoproteins) were identified. Homologs of proteins involved in cell cycle, vesicular trafficking and signal transduction were identified, which may be involved in en/excystation and cell growth of E. invadens. Finally, multiple copies of a number of E. invadens genes coding for predicted enzymes involved in core metabolism and the targets of anti-amoebic drugs were identified.

  14. Comparison of Two Immunoassays for Detection of Entamoeba histolytica▿

    OpenAIRE

    Buss, Sarah; Kabir, Mamun; Petri, William A.; Haque, Rashidul

    2008-01-01

    Effective diagnostic tools are essential in order to combat disease caused by the parasite Entamoeba histolytica. In this study, we compared the commercially available Ridascreen Entamoeba test (R-Biopharm) and the E. histolytica II test (Techlab), and we found that the E. histolytica II test detects E. histolytica infections more accurately.

  15. Heat Shock Protein 90 regulates encystation in Entamoeba

    Directory of Open Access Journals (Sweden)

    Meetali eSingh

    2015-10-01

    Full Text Available Enteric protozoan Entamoeba histolytica is a major cause of debilitating diarrheal infection worldwide with high morbidity and mortality. Even though the clinical burden of this parasite is very high, this infection is categorized as a neglected disease. Parasite is transmitted through feco-oral route and exhibit two distinct stages namely – trophozoites and cysts. Mechanism and regulation of encystation is not clearly understood. Previous studies have established the role of Heat shock protein 90 (Hsp90 in regulating stage transition in various protozoan parasites like Giardia, Plasmodium, Leishmania and Toxoplasma. Our study for the first time reports that Hsp90 plays a crucial role in life cycle of Entamoeba as well. We identify Hsp90 to be a negative regulator of encystation in Entamoeba. We also show that Hsp90 inhibition interferes with the process of phagocytosis in Entamoeba. Overall, we show that Hsp90 plays an important role in virulence and transmission of Entamoeba.

  16. The nucleolus in Entamoeba histolytica and Entamoeba invadens is located at the nuclear periphery.

    Science.gov (United States)

    Jhingan, Gagan Deep; Panigrahi, Sunil K; Bhattacharya, Alok; Bhattacharya, Sudha

    2009-09-01

    The ribosomal RNA genes in the human parasite Entamoeba histolytica and its reptilian counterpart Entamoeba invadens are located on extrachromosomal circles. The expression of rRNA genes generally takes place in a specialized nuclear compartment-the nucleolus. In Entamoeba species the nuclear space that may be called the nucleolus has yet to be defined. Previous studies showed that the rDNA circles are located at the nuclear periphery. Here we have raised antibodies against the E. histolytica homologue of fibrillarin, a highly conserved protein known to be a marker for nucleolus. These antibodies cross-reacted preferentially with the nuclear periphery, forming a peripheral ring. There was complete colocalization of fibrillarin with the signal obtained by antibodies against E. histolytica RNA polymerase I (but not polymerase II and III), strongly suggesting that the nucleolus in E. histolytica is indeed located at the nuclear periphery. The dynamic nature of the nucleolus was evident when cells were subjected to a variety of growth stresses. Although the peripheral nucleolar structure was retained, stress was accompanied by significant cytoplasmic localization of RNA polymerase I, and to some extent fibrillarin. The nucleolus in E. invadens was also located at the nuclear periphery. When these cells were induced to encyst the nucleolar ring structure was lost, giving way to small, fragmented foci. This study gives the first clear insight into nucleolar structure in Entamoeba.

  17. Noninvasive intestinal amebiasis: Entamoeba histolytica colonization without invasion.

    Science.gov (United States)

    Nair, Gayatri V; Variyam, Easwaran P

    2014-10-01

    Entamoeba histolytica infection remains a major cause of morbidity and mortality worldwide. Although research with the organism began in the late nineteenth century, our understanding of the natural history of the infection remains incomplete and is heavily based on expert opinion. Most persons infected with E. histolytica are carriers with the organism colonizing the large intestine. Host defense mechanisms that prevent invasive diseases are poorly understood. A timely review could lead to renewed interest. We herein review 2012 and 2013 publications related to the epidemiology, diagnosis, management and potential mechanisms that enable noninvasive E. histolytica colonization without invasion. There are several publications that advance our knowledge in the first three categories listed above, but studies of mechanisms for noninvasive E. histolytica colonization are glaringly few.

  18. The genetics of age-related macular degeneration.

    Science.gov (United States)

    Guymer, Robyn

    2001-07-01

    AIM: To review the genetics of age-related macular degeneration (AMD). The pathogenesis of AMD, the leading cause of severe visual disability and blindness in our community, remains unknown. However, AMD is regarded as a genetic disease where family history of AMD is a significant risk factor for the disease. Understanding the genetic factors associated with AMD offers the greatest chance for understanding the underlying disease processes. METHODS: Through a review of the literature and the use of original research findings, the current knowledge of the genetics of AMD is explored. CONCLUSION: AMD is increasing in prevalence and remains a major challenge for eye heath providers. Finding the genes that are associated with AMD offers the greatest chance for the development of preventative strategies and treatments.

  19. Fitness-related patterns of genetic variation in rhesus macaques.

    Science.gov (United States)

    Blomquist, Gregory E

    2009-03-01

    The patterning of quantitative genetic descriptions of genetic and residual variation for 15 skeletal and six life history traits was explored in a semi-free-ranging group of rhesus macaques (Macaca mulatta Zimmerman 1780). I tested theoretical predictions that explain the magnitude of genetic and residual variation as a result of 1. strength of a trait's association with evolutionary fitness, or 2. developmental and physiological relationships among traits. I found skeletal traits had higher heritabilities and lower coefficients of residual variation than more developmentally and physiologically dependent life history traits. Total lifetime fertility had a modest heritability (0.336) in this population, and traits with stronger correlations to fitness had larger amounts of residual variance. Censoring records of poorly-performing individuals on lifetime fertility and lifespan substantially reduced their heritabilities. These results support models for the fitness-related patterning of genetic variation based on developmental and physiological relationships among traits rather than the action of selection eroding variation.

  20. The genetics of anxiety-related negative valence system traits.

    Science.gov (United States)

    Savage, Jeanne E; Sawyers, Chelsea; Roberson-Nay, Roxann; Hettema, John M

    2017-03-01

    NIMH's Research Domain Criteria (RDoC) domain of negative valence systems (NVS) captures constructs of negative affect such as fear and distress traditionally subsumed under the various internalizing disorders. Through its aims to capture dimensional measures that cut across diagnostic categories and are linked to underlying neurobiological systems, a large number of phenotypic constructs have been proposed as potential research targets. Since "genes" represent a central "unit of analysis" in the RDoC matrix, it is important for studies going forward to apply what is known about the genetics of these phenotypes as well as fill in the gaps of existing knowledge. This article reviews the extant genetic epidemiological data (twin studies, heritability) and molecular genetic association findings for a broad range of putative NVS phenotypic measures. We find that scant genetic epidemiological data is available for experimentally derived measures such as attentional bias, peripheral physiology, or brain-based measures of threat response. The molecular genetic basis of NVS phenotypes is in its infancy, since most studies have focused on a small number of candidate genes selected for putative association to anxiety disorders (ADs). Thus, more research is required to provide a firm understanding of the genetic aspects of anxiety-related NVS constructs. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. Reasonable Foreseeability and Liability in Relation to Genetically Modified Organisms

    Science.gov (United States)

    Khoury, Lara; Smyth, Stuart

    2007-01-01

    This article examines problems that may arise when addressing liability resulting from the genetic modification of microbes, animals, and plants. More specifically, it evaluates how uncertainties relating to the outcomes of these biotechnological innovations affect--or may affect--the courts' application of the reasonable foreseeability…

  2. Genetics Home Reference: ZAP70-related severe combined immunodeficiency

    Science.gov (United States)

    ... related SCID is one of several forms of severe combined immunodeficiency, a group of disorders with several genetic causes. Children with SCID lack ... Foundation Jeffrey Modell Foundation National Organization for Rare Disorders ... ClinicalTrials.gov (1 link) ClinicalTrials.gov Scientific Articles ...

  3. First molecular identification of Entamoeba polecki in a piglet in Japan and implications for aggravation of ileitis by coinfection with Lawsonia intracellularis.

    Science.gov (United States)

    Matsubayashi, Makoto; Kanamori, Kenta; Sadahiro, Masayuki; Tokoro, Masaharu; Abe, Niichiro; Haritani, Makoto; Shibahara, Tomoyuki

    2015-08-01

    Parasitic Entamoeba spp. are found in many vertebrate species including humans, as well as many livestock including pigs. In pigs, three Entamoeba spp., E. suis, and E. polecki and E. histolytica as zoonotic species, have been identified, but their pathogenicity has not been fully characterized. Here, we report the bacteriological, virological, and histopathological examination of three piglets with chronic diarrhea. Two animals appeared to be additionally infected with Lawsonia intracellularis, which caused a characteristic proliferative ileitis. In the piglet infected with Entamoeba spp., the trophozoites (approximately 10-15 μm with one nucleus in their cytoplasm) invaded into the lamina propria and the disease was worsened by the formation of ulcers and pseudomembranes. Genetic analysis identified the parasite as E. polecki (99.5% identity). Although E. polecki in humans or animals might be less pathogenic in the case of a single infection, coinfections with other pathogens including L. intracellularis may increase the severity of the disease.

  4. Novel TPR-containing subunit of TOM complex functions as cytosolic receptor for Entamoeba mitosomal transport.

    Science.gov (United States)

    Makiuchi, Takashi; Mi-ichi, Fumika; Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

    2013-01-01

    Under anaerobic environments, the mitochondria have undergone remarkable reduction and transformation into highly reduced structures, referred as mitochondrion-related organelles (MROs), which include mitosomes and hydrogenosomes. In agreement with the concept of reductive evolution, mitosomes of Entamoeba histolytica lack most of the components of the TOM (translocase of the outer mitochondrial membrane) complex, which is required for the targeting and membrane translocation of preproteins into the canonical aerobic mitochondria. Here we showed, in E. histolytica mitosomes, the presence of a 600-kDa TOM complex composed of Tom40, a conserved pore-forming subunit, and Tom60, a novel lineage-specific receptor protein. Tom60, containing multiple tetratricopeptide repeats, is localized to the mitosomal outer membrane and the cytosol, and serves as a receptor of both mitosomal matrix and membrane preproteins. Our data indicate that Entamoeba has invented a novel lineage-specific shuttle receptor of the TOM complex as a consequence of adaptation to an anaerobic environment.

  5. Worldwide genealogy of Entamoeba histolytica: an overview to understand haplotype distribution and infection outcome.

    Science.gov (United States)

    Zermeño, Valeria; Ximénez, Cecilia; Morán, Patricia; Valadez, Alicia; Valenzuela, Olivia; Rascón, Edgar; Diaz, Daniel; Cerritos, René

    2013-07-01

    Although Entamoeba histolytica is one of the most prevalent intestinal parasites, how the different strains of this species are distributed all over the world and how different genotypes are associated with the infection outcome are yet to be fully understood. Recently, the use of a number of molecular markers has made the characterization of several genotypes in those regions with high incidence of amoebiasis possible. This work proposes the first genealogy of E. histolytica, with an haplotype network based on two tRNA gene-linked array of Short Tandem Repeats (STRs) reported until today, and 47 sequences from 39 new isolates of Mexican Amoebic Liver Abscesses (ALA) samples. One hundred and three sequences were obtained from D-A locus, their information about the geographic region of isolation as well as clinical diagnosis were also collected. One hundred and five sequences from N-K2 locus were also obtained as well as the region of isolation, but the information about clinical diagnosis was not available in all cases. The most abundant and widely distributed haplotype in the world is the one of E. histolytica HM1:IMSS strain. This was found in Mexico, Bangladesh, Japan, China and USA and is associated to symptomatic patients as well as asymptomatic cyst passers. Many other haplotypes were found only in a single country. Both genealogies suggest that there are no lineages within the networks that may be related to a particular geographic region or infection outcome. A concatenated analysis of the two molecular markers revealed 12 different combinations, which suggests the possibility of genetic recombination events. The present study is the first to propose a global genealogy of this species and suggests that there are still many genotypes to be discovered. The genotyping of new isolates will help to understand the great diversity and genetic structure of this parasite.

  6. Discrimination, crypticity, and incipient taxa in entamoeba.

    Science.gov (United States)

    Espinosa, Avelina; Paz-Y-Miño-C, Guillermo

    2012-01-01

    Persistent difficulties in resolving clear lineages in diverging populations of prokaryotes or unicellular eukaryotes (protistan polyphyletic groups) are challenging the classical species concept. Although multiple integrated approaches would render holistic taxonomies, most phylogenetic studies are still based on single-gene or morphological traits. Such methodologies conceal natural lineages, which are considered "cryptic." The concept of species is considered artificial and inadequate to define natural populations. Social organisms display differential behaviors toward kin than to nonrelated individuals. In "social" microbes, kin discrimination has been used to help resolve crypticity. Aggregative behavior could be explored in a nonsocial protist to define phylogenetic varieties that are considered "cryptic." Two Entamoeba invadens strains, IP-1 and VK-1:NS are considered close populations of the same "species." This study demonstrates that IP-1 and VK-1:NS trophozoites aggregate only with alike members and discriminate members of different strains based on behavioral and chemical signals. Combined morphological, behavioral/chemical, and ecological studies could improve Archamoebae phylogenies and define cryptic varieties. Evolutionary processes in which selection acted continuously and cumulatively on ancestors of Entamoeba populations gave rise to chemical and behavioral signals that allowed individuals to discriminate nonpopulation members and, gradually, to the emergence of new lineages; alternative views that claim a "Designer" or "Creator" as responsible for protistan diversity are unfounded.

  7. Amoebic liver abscess production by Entamoeba dispar.

    Science.gov (United States)

    Dolabella, Silvio S; Serrano-Luna, Jesús; Navarro-García, Fernando; Cerritos, René; Ximénez, Cecilia; Galván-Moroyoqui, José Manuel; Silva, Edward F; Tsutsumi, Víctor; Shibayama, Mineko

    2012-01-01

    Although Entamoeba dispar displays a similar morphology to Entamoeba histolytica, cellular and molecular studies have revealed significant differences between these two amoebae, including the former being characterized as non-pathogenic and the later as pathogenic. However, recent in vivo and in vitro experiments have shown that E. dispar strains of different origin are capable of causing liver damage and destroying cell culture lines in the presence of common intestinal bacteria. These results suggested that E. dispar may present pathogenic behavior according to the specific E. dispar strain, culture and environmental conditions. To investigate this possibility, we carried out in vivo and in vitro studies using a xenic strain E. dispar (ICB-ADO) isolated from a symptomatic non-dysenteric Brazilian patient. This strain was able to induce liver necrosis in a hamster model that was more severe than that produced by E. histolytica. The ICB-ADO isolate also caused significantly more destruction of cultured MDCK cells and increased loss of transepithelial resistance than did the E. histolytica. Xenic E. dispar exhibited high proteolytic activity, which was partially inhibited by the addition of cysteine-protease inhibitors. Based on our biochemical and molecular characterization of E. dispar (ICB-ADO) xenic culture and its ability to produce liver abscesses, we conclude that this specific strain can indeed produce tissue damage, distinct from the frequently used non- pathogenic E. dispar SAW 760 strain.

  8. Entamoeba mitosomes play an important role in encystation by association with cholesteryl sulfate synthesis

    Science.gov (United States)

    Mi-ichi, Fumika; Miyamoto, Tomofumi; Takao, Shouko; Jeelani, Ghulam; Hashimoto, Tetsuo; Hara, Hiromitsu; Nozaki, Tomoyoshi; Yoshida, Hiroki

    2015-01-01

    Hydrogenosomes and mitosomes are mitochondrion-related organelles (MROs) that have highly reduced and divergent functions in anaerobic/microaerophilic eukaryotes. Entamoeba histolytica, a microaerophilic, parasitic amoebozoan species, which causes intestinal and extraintestinal amoebiasis in humans, possesses mitosomes, the existence and biological functions of which have been a longstanding enigma in the evolution of mitochondria. We previously demonstrated that sulfate activation, which is not generally compartmentalized to mitochondria, is a major function of E. histolytica mitosomes. However, because the final metabolites of sulfate activation remain unknown, the overall scheme of this metabolism and the role of mitosomes in Entamoeba have not been elucidated. In this study we purified and identified cholesteryl sulfate (CS) as a final metabolite of sulfate activation. We then identified the gene encoding the cholesteryl sulfotransferase responsible for synthesizing CS. Addition of CS to culture media increased the number of cysts, the dormant form that differentiates from proliferative trophozoites. Conversely, chlorate, a selective inhibitor of the first enzyme in the sulfate-activation pathway, inhibited cyst formation in a dose-dependent manner. These results indicate that CS plays an important role in differentiation, an essential process for the transmission of Entamoeba between hosts. Furthermore, we show that Mastigamoeba balamuthi, an anaerobic, free-living amoebozoan species, which is a close relative of E. histolytica, also has the sulfate-activation pathway in MROs but does not possess the capacity for CS production. Hence, we propose that a unique function of MROs in Entamoeba contributes to its adaptation to its parasitic life cycle. PMID:25986376

  9. Host tissue destruction by Entamoeba histolytica: molecules mediating adhesion, cytolysis, and proteolysis

    Directory of Open Access Journals (Sweden)

    Rolf D. Horstmann

    1992-01-01

    Full Text Available Entamoeba histolytica, the protozoan parasite causing human amoebisis, has recently been found to comprise two genetically distinct forms, potentially pathogenic and constitutively nonpathogenic ones. Host tissue destruction by pathogenic forms is belived to result from cell functions mediaed by a lectin-type adherence receptor, a pore-forming peptide involved in host cell lysis, and abundant expression of cysteine proteinase(s. Isolation and molecular cloning of these amoeba products have provided the tools for structural analyses and manipulations of cell functions including comparisons between pathogenic and nonpathogenic forms.

  10. Extensive transcriptome analysis correlates the plasticity of Entamoeba histolytica pathogenesis to rapid phenotype changes depending on the environment

    Science.gov (United States)

    Weber, Christian; Koutero, Mikael; Dillies, Marie-Agnes; Varet, Hugo; Lopez-Camarillo, Cesar; Coppée, Jean Yves; Hon, Chung-Chau; Guillén, Nancy

    2016-01-01

    Amoebiasis is a human infectious disease due to the amoeba parasite Entamoeba histolytica. The disease appears in only 20% of the infections. Diversity in phenotypes may occur within the same infectious strain in the gut; for instance, parasites can be commensal (in the intestinal lumen) or pathogenic (inside the tissue). The degree of pathogenesis of clinical isolates varies greatly. These findings raise the hypothesis that genetic derivation may account for amoebic diverse phenotypes. The main goal of this study was to analyse gene expression changes of a single virulent amoebic strain in different environmental contexts where it exhibit different degrees of virulence, namely isolated from humans and maintained through animal liver passages, in contact with the human colon and short or prolonged in vitro culture. The study reveals major transcriptome changes in virulent parasites upon contact with human colon explants, including genes related to sugar metabolism, cytoskeleton rearrangement, stress responses and DNA repair. Furthermore, in long-term cultured parasites, drastic changes in gene expression for proteins with functions for proteasome and tRNA activities were found. Globally we conclude that rapid changes in gene expression rather than genetic derivation can sustain the invasive phenotype of a single virulent isolate of E. histolytica. PMID:27767091

  11. Mobile genetic elements related to carbapenem resistance in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Mariana Pagano

    Full Text Available Abstract Acinetobacter baumannii is widely recognized as an important pathogen associated with nosocomial infections. The treatment of these infections is often difficult due to the acquisition of resistance genes. A. baumannii presents a high genetic plasticity which allows the accumulation of these resistance determinants leading to multidrug resistance. It is highlighted the importance of the horizontal transfer of resistance genes, through mobile genetic elements and its relationship with increased incidence of multidrug resistant A. baumannii in hospitals. Considering that resistance to carbapenems is very important from the clinical and epidemiological point of view, the aim of this article is to present an overview of the current knowledge about genetic elements related to carbapenem resistance in A. baumannii such as integrons, transposons, resistance islands and insertion sequences.

  12. Introduction to International Ethical Standards Related to Genetics and Genomics

    Directory of Open Access Journals (Sweden)

    Seon-Hee Yim

    2013-12-01

    Full Text Available The rapid advances in genetic knowledge and technology raise various, sometimes unprecedented, ethical dilemmas in the scientific community as well as the public realm. To deal with these dilemmas, the international community has prepared and issued ethical standards in various formats. In this review, seven international standards regarding genetics and genomics will be briefly introduced in chronological order. Critical reflections on them will not be provided in this review, and naturally, they have their own problems and shortcomings. However, a common set of the principles expressed in them will be highlighted here, because they are still relevant, and many of them will be more relevant in the future. Some of the interesting contents will be selected and described. After that, the morality of one recent event related to whole-genome sequencing and person-identifiable genetic data will be explored based on those international standards.

  13. Genetic Architecture of Domestication-Related Traits in Maize.

    Science.gov (United States)

    Xue, Shang; Bradbury, Peter J; Casstevens, Terry; Holland, James B

    2016-09-01

    Strong directional selection occurred during the domestication of maize from its wild ancestor teosinte, reducing its genetic diversity, particularly at genes controlling domestication-related traits. Nevertheless, variability for some domestication-related traits is maintained in maize. The genetic basis of this could be sequence variation at the same key genes controlling maize-teosinte differentiation (due to lack of fixation or arising as new mutations after domestication), distinct loci with large effects, or polygenic background variation. Previous studies permit annotation of maize genome regions associated with the major differences between maize and teosinte or that exhibit population genetic signals of selection during either domestication or postdomestication improvement. Genome-wide association studies and genetic variance partitioning analyses were performed in two diverse maize inbred line panels to compare the phenotypic effects and variances of sequence polymorphisms in regions involved in domestication and improvement to the rest of the genome. Additive polygenic models explained most of the genotypic variation for domestication-related traits; no large-effect loci were detected for any trait. Most trait variance was associated with background genomic regions lacking previous evidence for involvement in domestication. Improvement sweep regions were associated with more trait variation than expected based on the proportion of the genome they represent. Selection during domestication eliminated large-effect genetic variants that would revert maize toward a teosinte type. Small-effect polygenic variants (enriched in the improvement sweep regions of the genome) are responsible for most of the standing variation for domestication-related traits in maize.

  14. The Effect of Nonsurgical Periodontal Therapy on Trichomonas Tenax and Entamoeba Gingivalis in Patients with Chronic Periodontitis.

    Science.gov (United States)

    Rashidi Maybodi, Fahimeh; Haerian Ardakani, Ahmad; Fattahi Bafghi, Ali; Haerian Ardakani, Alireza; Zafarbakhsh, Akram

    2016-09-01

    Trichomonas tenax and Entamoeba gingivalis are commensal protozoa which inhabit the human oral cavity. These parasites are found in patients with poor oral hygiene and might be a reason for progressive periodontal diseases. The aim of this study was to evaluate the effect of nonsurgical periodontal treatment on the frequency of these protozoa in saliva and plaque samples. In this clinical trial, samples of saliva and dental plaque were collected from 46 patients with moderate to severe chronic periodontitis before and after periodontal therapy. The samples were assessed for the frequency of parasites. The frequency of Entamoeba gingivalis was reduced in saliva (p= 0.007) and plaque (p= 0.027) three weeks after the treatment. Likewise, the frequency of Trichomonas tenax reduced in saliva (p= 0.030); however, the decrease was not significant in plaque (p= 0.913). Trichomonas tenax frequency in dental plaque directly related to the severity of periodontitis (r= 0.565, p≤ 0.000). In contrast, the number of Entamoeba gingivalis in both saliva (r= -0.405, p≤ 0.005) and plaque (r= -0.304, p= 0.040) was inversely related with the severity of the periodontal disease. Nonsurgical periodontal treatment could reduce the number of Trichomonas Tenax and Entamoeba gingivalis in the oral environment of patients with chronic periodontitis.

  15. The Effect of Nonsurgical Periodontal Therapy on Trichomonas Tenax and Entamoeba Gingivalis in Patients with Chronic Periodontitis

    Directory of Open Access Journals (Sweden)

    Fahimeh Rashidi Maybodi

    2016-09-01

    Full Text Available Statement of the Problem: Trichomonas tenax and Entamoeba gingivalis are com-mensal protozoa which inhabit the human oral cavity. These parasites are found in patients with poor oral hygiene and might be a reason for progressive periodontal diseases. Purpose: The aim of this study was to evaluate the effect of nonsurgical periodontal treatment on the frequency of these protozoa in saliva and plaque samples. Materials and Method: In this clinical trial, samples of saliva and dental plaque were collected from 46 patients with moderate to severe chronic periodontitis before and after periodontal therapy. The samples were assessed for the frequency of parasites. Results: The frequency of Entamoeba gingivalis was reduced in saliva (p= 0.007 and plaque (p= 0.027 three weeks after the treatment. Likewise, the frequency of Trichomonas tenax reduced in saliva (p= 0.030; however, the decrease was not significant in plaque (p= 0.913. Trichomonas tenax frequency in dental plaque directly related to the severity of periodontitis (r= 0.565, p≤ 0.000. In contrast, the number of Entamoeba gingivalis in both saliva (r= -0.405, p≤ 0.005 and plaque (r= -0.304, p= 0.040 was inversely related with the severity of the periodontal disease. Conclusion: Nonsurgical periodontal treatment could reduce the number of Trichomonas Tenax and Entamoeba gingivalis in the oral environment of patients with chronic periodontitis.

  16. The Effect of Nonsurgical Periodontal Therapy on Trichomonas Tenax and Entamoeba Gingivalis in Patients with Chronic Periodontitis

    Science.gov (United States)

    Rashidi Maybodi, Fahimeh; Haerian Ardakani, Ahmad; Fattahi Bafghi, Ali; Haerian Ardakani, Alireza; Zafarbakhsh, Akram

    2016-01-01

    Statement of the Problem Trichomonas tenax and Entamoeba gingivalis are commensal protozoa which inhabit the human oral cavity. These parasites are found in patients with poor oral hygiene and might be a reason for progressive periodontal diseases. Purpose The aim of this study was to evaluate the effect of nonsurgical periodontal treatment on the frequency of these protozoa in saliva and plaque samples. Materials and Method In this clinical trial, samples of saliva and dental plaque were collected from 46 patients with moderate to severe chronic periodontitis before and after periodontal therapy. The samples were assessed for the frequency of parasites. Results The frequency of Entamoeba gingivalis was reduced in saliva (p= 0.007) and plaque (p= 0.027) three weeks after the treatment. Likewise, the frequency of Trichomonas tenax reduced in saliva (p= 0.030); however, the decrease was not significant in plaque (p= 0.913). Trichomonas tenax frequency in dental plaque directly related to the severity of periodontitis (r= 0.565, p≤ 0.000). In contrast, the number of Entamoeba gingivalis in both saliva (r= -0.405, p≤ 0.005) and plaque (r= -0.304, p= 0.040) was inversely related with the severity of the periodontal disease. Conclusion Nonsurgical periodontal treatment could reduce the number of Trichomonas Tenax and Entamoeba gingivalis in the oral environment of patients with chronic periodontitis. PMID:27602391

  17. Molecular Epidemiology of Entamoeba: First Description of Entamoeba moshkovskii in a Rural Area from Central Colombia.

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    Myriam Consuelo López

    Full Text Available Entamoeba histolytica, E. dispar and E. moshkovskii are the most frequent species described in human infection where E. histolytica is the only true pathogen. The epidemiology of this infection is complex due to the absence of a routine exam that allows a correct discrimination of the Entamoeba species complex. Therefore, molecular methods appear as the unique epidemiological tool to accomplish the species discrimination. Herein, we conducted a cross-sectional study to determine the frequency of Entamoeba species infections in a group of asymptomatic individuals from a rural area in central Colombia.A total of 181 fecal samples from asymptomatic children under 16 years old from the hamlet La Vírgen, Cundinamarca (Colombia that voluntarily accepted to participate in the study were collected. The fecal samples were examined by light microscopy and DNA-extracted, subsequently submitted to molecular discrimination of E. dispar/E. histolytica/E. moshkovskii infection based on a multiplex PCR assay targeting the 18S rRNA fragment. To confirm the species description, twenty samples were randomly submitted to DNA sequencing of the aforementioned fragment. By direct microscopic examination, frequency of the complex E. histolytica/E. dispar/E. moshkovskii was 18.8% (34/181. PCR showed a frequency of 49.1% (89/181, discriminated as 23.2% (42/181 that were positive for E. dispar, 25.4% (46/181 for E. moshkovskii and 0.55% (1/ 181 for E. histolytica. Also, mixed infections were detected between E. dispar and E. moshkovskii at 4.42% (8/181 of the samples. Molecular barcoding confirmed the diagnosis depicted by the multiplex PCR assay.This is the first description of E. moshkovskii in Colombia and the second report in South-America to our knowledge. Our results suggest the need to unravel the true epidemiology of Entamoeba infections around the world, including the real pathogenic role that E. moshkovskii may have.

  18. Inference of distant genetic relations in humans using "1000 genomes".

    Science.gov (United States)

    Al-Khudhair, Ahmed; Qiu, Shuhao; Wyse, Meghan; Chowdhury, Shilpi; Cheng, Xi; Bekbolsynov, Dulat; Saha-Mandal, Arnab; Dutta, Rajib; Fedorova, Larisa; Fedorov, Alexei

    2015-01-07

    Nucleotide sequence differences on the whole-genome scale have been computed for 1,092 people from 14 populations publicly available by the 1000 Genomes Project. Total number of differences in genetic variants between 96,464 human pairs has been calculated. The distributions of these differences for individuals within European, Asian, or African origin were characterized by narrow unimodal peaks with mean values of 3.8, 3.5, and 5.1 million, respectively, and standard deviations of 0.1-0.03 million. The total numbers of genomic differences between pairs of all known relatives were found to be significantly lower than their respective population means and in reverse proportion to the distance of their consanguinity. By counting the total number of genomic differences it is possible to infer familial relations for people that share down to 6% of common loci identical-by-descent. Detection of familial relations can be radically improved when only very rare genetic variants are taken into account. Counting of total number of shared very rare single nucleotide polymorphisms (SNPs) from whole-genome sequences allows establishing distant familial relations for persons with eighth and ninth degrees of relationship. Using this analysis we predicted 271 distant familial pairwise relations among 1,092 individuals that have not been declared by 1000 Genomes Project. Particularly, among 89 British and 97 Chinese individuals we found three British-Chinese pairs with distant genetic relationships. Individuals from these pairs share identical-by-descent DNA fragments that represent 0.001%, 0.004%, and 0.01% of their genomes. With affordable whole-genome sequencing techniques, very rare SNPs should become important genetic markers for familial relationships and population stratification. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Genetic Architecture of Plasma Adiponectin Overlaps With the Genetics of Metabolic Syndrome–Related Traits

    Science.gov (United States)

    Henneman, Peter; Aulchenko, Yurii S.; Frants, Rune R.; Zorkoltseva, Irina V.; Zillikens, M. Carola; Frolich, Marijke; Oostra, Ben A.; van Dijk, Ko Willems; van Duijn, Cornelia M.

    2010-01-01

    OBJECTIVE Adiponectin, a hormone secreted by adipose tissue, is of particular interest in metabolic syndrome, because it is inversely correlated with obesity and insulin sensitivity. However, it is not known to what extent the genetics of plasma adiponectin and the genetics of obesity and insulin sensitivity are interrelated. We aimed to evaluate the heritability of plasma adiponectin and its genetic correlation with the metabolic syndrome and metabolic syndrome–related traits and the association between these traits and 10 ADIPOQ single nucleotide polymorphisms (SNPs). RESEARCH DESIGN AND METHODS We made use of a family-based population, the Erasmus Rucphen Family study (1,258 women and 967 men). Heritability analysis was performed using a polygenic model. Genetic correlations were estimated using bivariate heritability analyses. Genetic association analysis was performed using a mixed model. RESULTS Plasma adiponectin showed a heritability of 55.1%. Genetic correlations between plasma adiponectin HDL cholesterol and plasma insulin ranged from 15 to 24% but were not significant for fasting glucose, triglycerides, blood pressure, homeostasis model assessment of insulin resistance (HOMA-IR), and C-reactive protein. A significant association with plasma adiponectin was found for ADIPOQ variants rs17300539 and rs182052. A nominally significant association was found with plasma insulin and HOMA-IR and ADIPOQ variant rs17300539 after adjustment for plasma adiponectin. CONCLUSIONS The significant genetic correlation between plasma adiponectin and HDL cholesterol and plasma insulin should be taken into account in the interpretation of genome-wide association studies. Association of ADIPOQ SNPs with plasma adiponectin was replicated, and we showed association between one ADIPOQ SNP and plasma insulin and HOMA-IR. PMID:20067957

  20. Detection of the amoeba Entamoeba gingivalis in periodontal pockets.

    Science.gov (United States)

    Bonner, Mark; Amard, Véronique; Bar-Pinatel, Charlotte; Charpentier, Frédéric; Chatard, Jean-Michel; Desmuyck, Yvan; Ihler, Serge; Rochet, Jean-Pierre; Roux de La Tribouille, Véronique; Saladin, Luc; Verdy, Marion; Gironès, Núria; Fresno, Manuel; Santi-Rocca, Julien

    2014-01-01

    Periodontitis is a public health issue, being one of the most prevalent diseases worldwide. However, the aetiology of the disease is still unclear: genetics of patients cannot explain the dispersed or isolated localisation of gingival pockets, while bacteria-based models are insufficient to distinguish gingivitis and periodontitis. The possible role of parasites in the establishment of periodontitis has been poorly studied until now. The aim of this project was to study a potential link between colonisation of gingival crevices by the amoeba Entamoeba gingivalis and periodontitis. In eight different dental clinics in France, samples were taken in periodontal pockets (72) or healthy sites (33), and submitted to microscopic observation and molecular identification by PCR with a new set of primers designed to specifically detect E. gingivalis. This blind sample analysis showed the strong sensitivity of PCR compared with clinical diagnosis (58/72 = 81%), and microscopy (51/65 = 78%). The results of this work show that the parasites detected by microscopy mainly - if not exclusively - belong to the species E. gingivalis and that the presence of the parasite is correlated with periodontitis. © M. Bonner et al., published by EDP Sciences, 2014.

  1. Immune Response of Amebiasis and Immune Evasion by Entamoeba histolytica

    Science.gov (United States)

    Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

    2016-01-01

    Entamoeba histolytica is a protozoan parasite and the causative agent of amebiasis. It is estimated approximately 1% of humans are infected with E. histolytica, resulting in an estimate of 100,000 deaths annually. Clinical manifestations of amebic infection range widely from asymptomatic to severe symptoms, including dysentery and extra-intestinal abscesses. Like other infectious diseases, it is assumed that only ~20% of infected individuals develop symptoms, and genetic factors of both the parasite and humans as well as the environmental factors, e.g., microbiota, determine outcome of infection. There are multiple essential steps in amebic infection: degradation of and invasion into the mucosal layer, adherence to the intestinal epithelium, invasion into the tissues, and dissemination to other organs. While the mechanisms of invasion and destruction of the host tissues by the amebae during infection have been elucidated at the molecular levels, it remains largely uncharacterized how the parasite survive in the host by evading and attacking host immune system. Recently, the strategies for immune evasion by the parasite have been unraveled, including immunomodulation to suppress IFN-γ production, elimination of immune cells and soluble immune mediators, and metabolic alterations against reactive oxygen and nitrogen species to fend off the attack from immune system. In this review, we summarized the latest knowledge on immune reaction and immune evasion during amebiasis. PMID:27242782

  2. Immune Response of Amebiasis and Immune Evasion by Entamoeba histolytica.

    Science.gov (United States)

    Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

    2016-01-01

    Entamoeba histolytica is a protozoan parasite and the causative agent of amebiasis. It is estimated approximately 1% of humans are infected with E. histolytica, resulting in an estimate of 100,000 deaths annually. Clinical manifestations of amebic infection range widely from asymptomatic to severe symptoms, including dysentery and extra-intestinal abscesses. Like other infectious diseases, it is assumed that only ~20% of infected individuals develop symptoms, and genetic factors of both the parasite and humans as well as the environmental factors, e.g., microbiota, determine outcome of infection. There are multiple essential steps in amebic infection: degradation of and invasion into the mucosal layer, adherence to the intestinal epithelium, invasion into the tissues, and dissemination to other organs. While the mechanisms of invasion and destruction of the host tissues by the amebae during infection have been elucidated at the molecular levels, it remains largely uncharacterized how the parasite survive in the host by evading and attacking host immune system. Recently, the strategies for immune evasion by the parasite have been unraveled, including immunomodulation to suppress IFN-γ production, elimination of immune cells and soluble immune mediators, and metabolic alterations against reactive oxygen and nitrogen species to fend off the attack from immune system. In this review, we summarized the latest knowledge on immune reaction and immune evasion during amebiasis.

  3. Detection of the amoeba Entamoeba gingivalis in periodontal pockets

    Directory of Open Access Journals (Sweden)

    Bonner Mark

    2014-01-01

    Full Text Available Periodontitis is a public health issue, being one of the most prevalent diseases worldwide. However, the aetiology of the disease is still unclear: genetics of patients cannot explain the dispersed or isolated localisation of gingival pockets, while bacteria-based models are insufficient to distinguish gingivitis and periodontitis. The possible role of parasites in the establishment of periodontitis has been poorly studied until now. The aim of this project was to study a potential link between colonisation of gingival crevices by the amoeba Entamoeba gingivalis and periodontitis. In eight different dental clinics in France, samples were taken in periodontal pockets (72 or healthy sites (33, and submitted to microscopic observation and molecular identification by PCR with a new set of primers designed to specifically detect E. gingivalis. This blind sample analysis showed the strong sensitivity of PCR compared with clinical diagnosis (58/72 = 81%, and microscopy (51/65 = 78%. The results of this work show that the parasites detected by microscopy mainly – if not exclusively – belong to the species E. gingivalis and that the presence of the parasite is correlated with periodontitis.

  4. Entamoeba Encystation: New Targets to Prevent the Transmission of Amebiasis

    OpenAIRE

    Mi-ichi, Fumika; Yoshida, Hiroki; Hamano, Shinjiro

    2016-01-01

    Amebiasis is caused by Entamoeba histolytica infection and can produce a broad range of clinical signs, from asymptomatic cases to patients with obvious symptoms. The current epidemiological and clinical statuses of amebiasis make it a serious public health problem worldwide. The Entamoeba life cycle consists of the trophozoite, the causative agent for amebiasis, and the cyst, the form responsible for transmission. These two stages are connected by “encystation” and “excystation.” Hence, deve...

  5. Polyacrylamide gel electrophoresis of isoenzymes from Entamoeba species.

    OpenAIRE

    Mathews, H M; Moss, D M; Healy, G R; Visvesvara, G S

    1983-01-01

    In this preliminary report, we describe a polyacrylamide gel electrophoresis technique for the resolution of isoenzyme patterns of four isolates of Entamoeba histolytica and one isolate of Entamoeba coli. Our findings were similar to previous findings for three enzyme systems: maleic enzyme (malate dehydrogenase [EC 1.1.1.40]), hexokinase (EC 2.7.1.1), and phosphoglucomutase (EC 2.7.5.1). We found preliminary evidence that glucosephosphate isomerase (EC 5.3.1.9) may also differentiate invasiv...

  6. Genetic variability of six French meat sheep breeds in relation to their genetic management

    Directory of Open Access Journals (Sweden)

    Coralie Danchin-Burge

    2003-11-01

    Full Text Available Abstract Some demographic parameters, the genetic structure and the evolution of the genetic variability of six French meat sheep breeds were analysed in relation with their management. Four of these breeds are submitted to more or less intense selection: the Berrichon du Cher (BCH, Blanc du Massif Central (BMC, Charollais (CHA and Limousin (LIM; the other two breeds are under conservation: the Roussin de La Hague (RLH and Solognot (SOL. Genealogical data of the recorded animals born from 1970 to 2000 and of their known ancestors were used. The most balanced contributions of the different flocks to the sire-daughter path was found in the SOL. In the BCH, a single flock provided 43% of the sire-AI sire path, whereas the contributions of the flocks were more balanced in the BMC and LIM (the only other breeds where AI is used to a substantial amount. The distribution of the expected genetic contribution of the founder animals was found to be unbalanced, especially in the BCH and LIM. The effective numbers of ancestors (founders or not for the ewes born from 1996 to 2000 were equal to 35 (BCH, 144 (BMC, 112 (CHA, 69 (LIM, 40 (RLH and 49 (SOL. Inbreeding was not analysed in the BMC, due to incomplete pedigree information. From 1980 on, the rates of inbreeding, in percentage points per year, were +0.112 (BCH, +0.045 (CHA, +0.036 (LIM, +0.098 (RLH and +0.062 (SOL. The implications of the observed trends on genetic variability are discussed in relation to the genetic management of each breed. The need for a larger selection basis in the BCH, the efficiency of the rules applied in the SOL to preserve the genetic variability and the need for a more collective organisation in the CHA and RLH are outlined.

  7. Genetic polymorphisms related to testosterone metabolism in intellectually gifted boys.

    Science.gov (United States)

    Celec, Peter; Tretinárová, Denisa; Minárik, Gabriel; Ficek, Andrej; Szemes, Tomáš; Lakatošová, Silvia; Schmidtová, Eva; Turňa, Ján; Kádaši, Ľudevít; Ostatníková, Daniela

    2013-01-01

    Prepubertal testosterone levels are lower in intellectually gifted boys. The aim of this pilot study was to analyze potential genetic factors related to testosterone metabolism in control and gifted boys. Intellectually gifted (IQ>130; n = 95) and control (n = 67) boys were genotyped. Polymorphisms of interests were chosen in genes including androgen and estrogen receptors, 5-alpha reductase, aromatase and sex hormone binding globulin. Significant differences between control and gifted boys in genotype distributions were found for ESR2 (rs928554) and SHBG (rs1799941). A significantly lower number of CAG repeats in the AR gene were found in gifted boys. Our results support the role of genetic factors related to testosterone metabolism in intellectual giftedness. Increased androgen signaling might explain previous results of lower testosterone levels in intellectually gifted boys and add to the understanding of variability in cognitive abilities.

  8. Genetic Polymorphisms Related to Testosterone Metabolism in Intellectually Gifted Boys

    Science.gov (United States)

    Celec, Peter; Tretinárová, Denisa; Minárik, Gabriel; Ficek, Andrej; Szemes, Tomáš; Lakatošová, Silvia; Schmidtová, Eva; Turňa, Ján; Kádaši, Ľudevít; Ostatníková, Daniela

    2013-01-01

    Prepubertal testosterone levels are lower in intellectually gifted boys. The aim of this pilot study was to analyze potential genetic factors related to testosterone metabolism in control and gifted boys. Intellectually gifted (IQ>130; n = 95) and control (n = 67) boys were genotyped. Polymorphisms of interests were chosen in genes including androgen and estrogen receptors, 5-alpha reductase, aromatase and sex hormone binding globulin. Significant differences between control and gifted boys in genotype distributions were found for ESR2 (rs928554) and SHBG (rs1799941). A significantly lower number of CAG repeats in the AR gene were found in gifted boys. Our results support the role of genetic factors related to testosterone metabolism in intellectual giftedness. Increased androgen signaling might explain previous results of lower testosterone levels in intellectually gifted boys and add to the understanding of variability in cognitive abilities. PMID:23382957

  9. Genetic diversity analysis of salinity related germplasm in cotton

    OpenAIRE

    Lina Zhang; Wuwei Ye; Junjuan Wang; Baoxiang Fan; Delong Wang

    2010-01-01

    In order to study the genetic variation of salinity related cotton germplasm, 47 upland cotton accessions including 23 salinity tolerant materials and 24 salinity sensitive materials were explored using 88 simple sequence repeat (SSR) markers. We detected a total of 338 alleles at 88 SSR loci with an average of 3.841 alleles per locus, 333 of these alleles were detected in salinity tolerant germplasm and 312 alleles in salinity sensitive germplasm. Mean polymorphism information content (PIC),...

  10. Genetic determinants of obesity and related vascular diseases.

    Science.gov (United States)

    Winter, Yaroslav; Sankowski, Roman; Back, Tobias

    2013-01-01

    Obesity is one of the major risk factors of vascular diseases, and its prevalence is increasing worldwide. In the past decade, progress has been made in the understanding of genetic determinants of obesity and obesity-associated diseases. Genome-wide association studies identified a number of genetic variants associated with obesity. In addition to common variants, FTO and MC4R, new loci, such as TMEM18, KCTD15, GNPDA2, SH2B1, MTCH2, and NEGR1 have been detected. In the past years, abdominal obesity has been shown to be a more important vascular risk factor than the body mass index. In the context of vascular risk assessment, identification of genetic polymorphisms associated with accumulation of visceral fat is of special importance. Some polymorphisms associated with abdominal obesity, such as variants of gene encoding microsomal triglyceride transfer protein, have been already discovered. In this chapter, we provide a review of genetic determinants of obesity and discuss their role in obesity-related vascular diseases.

  11. Regulation of virulence of Entamoeba histolytica.

    Science.gov (United States)

    Marie, Chelsea; Petri, William A

    2014-01-01

    Entamoeba histolytica is the third-leading cause of parasitic mortality globally. E. histolytica infection generally does not cause symptoms, but the parasite has potent pathogenic potential. The origins, benefits, and triggers of amoebic virulence are complex. Amoebic pathogenesis entails depletion of the host mucosal barrier, adherence to the colonic lumen, cytotoxicity, and invasion of the colonic epithelium. Parasite damage results in colitis and, in some cases, disseminated disease. Both host and parasite genotypes influence the development of disease, as do the regulatory responses they govern at the host-pathogen interface. Host environmental factors determine parasite transmission and shape the colonic microenvironment E. histolytica infects. Here we highlight research that illuminates novel links between host, parasite, and environmental factors in the regulation of E. histolytica virulence.

  12. Effect of zinc on Entamoeba histolytica pathogenicity.

    Science.gov (United States)

    Vega Robledo, G B; Carrero, J C; Ortiz-Ortiz, L

    1999-06-01

    The present study analyzes the effects of zinc on Entamoeba histolytica activity and on its pathogenicity. Metal activity was evaluated in vitro with regard to the parasite's viability, replication, and adhesion to epithelial cells and in vivo with regard to its pathogenicity. The results obtained in vitro show that zinc at 1.0 mM concentration does not affect amebic viability; however, it does decrease amebic replication and adhesion (P vivo studies performed on a model of experimental liver abscess in the hamster indicate that the intraperitoneal administration of a single dose of zinc at 48 h after the intrahepatic inoculation of amebic trophozoites significantly inhibits (P vivo as manifested by inhibition of amebic pathogenicity.

  13. Seroprevalence of Entamoeba histolytica infection in China.

    Science.gov (United States)

    Yang, Bin; Chen, Yingdan; Wu, Liang; Xu, Longqi; Tachibana, Hiroshi; Cheng, Xunjia

    2012-07-01

    The seroprevalence of Entamoeba histolytica infection in the residents of seven provinces in China was examined by using an enzyme-linked immunosorbent assay with a crude antigen and a recombinant surface antigen, C-Igl, of the parasites. A total of 1,312 serum samples were investigated. The positivity rates for these two antigens were 11.05% and 6.25%, respectively. There was no significant difference in the seropositivity to E. histolytica between men and women. We used a logistic regression model and maximal-likelihood methods to estimate the prevalence of E. histolytica infection from sequential serologic data. Seropositivity in Sichuan, Guizhou, and Sinkiang Provinces was higher than that in Beijing, Shanghai, and Qinghai Provinces. The present study provides an overview of seropositivity to E. histolytica infection in seven provinces in China and use the logistic regression model estimation method to achieve a more accurate measure of amebiasis prevalence.

  14. Catecholamines in Entamoebae: recent (re)discoveries

    Indian Academy of Sciences (India)

    Dan Eichinger; Alida Coppi; Jesse Frederick; Salim Merali

    2002-11-01

    Free-living and enteric amoebae have similar two-stage life cycles, and both organisms depend on being able to monitor environmental conditions to determine whether to continue multiplying as trophozoites, or to differentiate into dormant or transmissible cysts. Conditions that support high trophozoite densities might also be expected to select for mechanisms of information exchange between these cells. We recently determined that trophozoites of at least one species of Entamoeba release and respond to catecholamine compounds during differentiation from the trophozoite stage into the cyst stage. It turns out that this is not an entirely novel finding, as a number of previous studies have demonstrated parts of this story in free-living or enteric amoebae. We briefly review here major points of the previous studies and describe some of our recent results that have extended them.

  15. Development of multiplex real-time polymerase chain reaction for detection of Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii in clinical specimens.

    Science.gov (United States)

    Hamzah, Zulhainan; Petmitr, Songsak; Mungthin, Mathirut; Leelayoova, Saovanee; Chavalitshewinkoon-Petmitr, Porntip

    2010-10-01

    Multiplex real-time polymerase chain reaction (PCR) was developed for differential detection of Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii. Specific primers were designed for all three species, and then differentiation of E. histolytica and E. dispar was achieved simultaneously using a hybridization probe and melting curve analysis, whereas E. moshkovskii was detected with a separate probe under the same condition. This assay detected as little as 0.2 pg of E. histolytica DNA and 2 pg each for E. dispar and E. moshkovskii DNA. Thirty-five clinical samples suspected to be E. histolytica infection by microscopy were tested. The results showed 32 positive samples; four samples were E. histolytica and 28 samples were E. dispar. Interestingly, one E. dispar positive sample showed a mixed infection with E. moshkovskii. This is the first report of E. moshkovskii infection from Thailand and this assay is currently the most rapid and sensitive method to differentiate these human amoebas.

  16. Virulence of ’Entamoeba histolytica’ According to the Strains in Korea.

    Science.gov (United States)

    Investigations are reported on the adaptation of Entamoeba histolytica strains to low temperature conditions. Nine strains of E. histolytica which...Electron microscopy of Entamoeba histolytica in culture and in intestinal mucosa are described. The ultrastructural differences among E. histolytica

  17. GENETIC PATHWAYS LEADING TO THERAPY-RELATED MYELOID NEOPLASMS

    Directory of Open Access Journals (Sweden)

    Angela Stoddart

    2011-05-01

    Full Text Available Therapy-related myeloid neoplasm (t-MN is a distinctive clinical syndrome occurring after exposure to chemotherapy or radiotherapy.  t-MN arises in most cases from a multipotential hematopoietic stem cell or, less commonly, in a lineage committed progenitor cell.  The prognosis for patients with t-MN is poor, as current forms of therapy are largely ineffective.  Cytogenetic analysis, molecular analysis and gene expression profiling analysis of t-MN has revealed that there are distinct subtypes of the disease; however, our understanding of the genetic basis of t-MN is incomplete.  Elucidating the genetic pathways and molecular networks that are perturbed in t-MNs, may facilitate the identification of therapeutic targets that can be exploited for the development of urgently-needed targeted therapies.

  18. Beyond the thale: comparative genomics and genetics of Arabidopsis relatives.

    Science.gov (United States)

    Koenig, Daniel; Weigel, Detlef

    2015-05-01

    For decades a small number of model species have rightly occupied a privileged position in laboratory experiments, but it is becoming increasingly clear that our knowledge of biology is greatly improved when informed by a broader diversity of species and evolutionary context. Arabidopsis thaliana has been the primary model organism for plants, benefiting from a high-quality reference genome sequence and resources for reverse genetics. However, recent studies have made a group of species also in the Brassicaceae family and closely related to A. thaliana a focal point for comparative molecular, genomic, phenotypic and evolutionary studies. In this Review, we emphasize how such studies complement continued study of the model plant itself, provide an evolutionary perspective and summarize our current understanding of genetic and phenotypic diversity in plants.

  19. Modelling the genetic risk in age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    Felix Grassmann

    Full Text Available Late-stage age-related macular degeneration (AMD is a common sight-threatening disease of the central retina affecting approximately 1 in 30 Caucasians. Besides age and smoking, genetic variants from several gene loci have reproducibly been associated with this condition and likely explain a large proportion of disease. Here, we developed a genetic risk score (GRS for AMD based on 13 risk variants from eight gene loci. The model exhibited good discriminative accuracy, area-under-curve (AUC of the receiver-operating characteristic of 0.820, which was confirmed in a cross-validation approach. Noteworthy, younger AMD patients aged below 75 had a significantly higher mean GRS (1.87, 95% CI: 1.69-2.05 than patients aged 75 and above (1.45, 95% CI: 1.36-1.54. Based on five equally sized GRS intervals, we present a risk classification with a relative AMD risk of 64.0 (95% CI: 14.11-1131.96 for individuals in the highest category (GRS 3.44-5.18, 0.5% of the general population compared to subjects with the most common genetic background (GRS -0.05-1.70, 40.2% of general population. The highest GRS category identifies AMD patients with a sensitivity of 7.9% and a specificity of 99.9% when compared to the four lower categories. Modeling a general population around 85 years of age, 87.4% of individuals in the highest GRS category would be expected to develop AMD by that age. In contrast, only 2.2% of individuals in the two lowest GRS categories which represent almost 50% of the general population are expected to manifest AMD. Our findings underscore the large proportion of AMD cases explained by genetics particularly for younger AMD patients. The five-category risk classification could be useful for therapeutic stratification or for diagnostic testing purposes once preventive treatment is available.

  20. Evidence that the Entamoeba histolytica Mitochondrial Carrier Family Links Mitosomal and Cytosolic Pathways through Exchange of 3'-Phosphoadenosine 5'-Phosphosulfate and ATP.

    Science.gov (United States)

    Mi-ichi, Fumika; Nozawa, Akira; Yoshida, Hiroki; Tozawa, Yuzuru; Nozaki, Tomoyoshi

    2015-11-01

    Entamoeba histolytica, a microaerophilic protozoan parasite, possesses mitosomes. Mitosomes are mitochondrion-related organelles that have largely lost typical mitochondrial functions, such as those involved in the tricarboxylic acid cycle and oxidative phosphorylation. The biological roles of Entamoeba mitosomes have been a long-standing enigma. We previously demonstrated that sulfate activation, which is not generally compartmentalized to mitochondria, is a major function of E. histolytica mitosomes. Sulfate activation cooperates with cytosolic enzymes, i.e., sulfotransferases (SULTs), for the synthesis of sulfolipids, one of which is cholesteryl sulfate. Notably, cholesteryl sulfate plays an important role in encystation, an essential process in the Entamoeba life cycle. These findings identified a biological role for Entamoeba mitosomes; however, they simultaneously raised a new issue concerning how the reactions of the pathway, separated by the mitosomal membranes, cooperate. Here, we demonstrated that the E. histolytica mitochondrial carrier family (EhMCF) has the capacity to exchange 3'-phosphoadenosine 5'-phosphosulfate (PAPS) with ATP. We also confirmed the cytosolic localization of all the E. histolytica SULTs, suggesting that in Entamoeba, PAPS, which is produced through mitosomal sulfate activation, is translocated to the cytosol and becomes a substrate for SULTs. In contrast, ATP, which is produced through cytosolic pathways, is translocated into the mitosomes and is a necessary substrate for sulfate activation. Taking our findings collectively, we suggest that EhMCF functions as a PAPS/ATP antiporter and plays a crucial role in linking the mitosomal sulfate activation pathway to cytosolic SULTs for the production of sulfolipids.

  1. An Entamoeba cysteine peptidase specifically expressed during encystation.

    Science.gov (United States)

    Ebert, Frank; Bachmann, Anna; Nakada-Tsukui, Kumiko; Hennings, Ina; Drescher, Babette; Nozaki, Tomoyoshi; Tannich, Egbert; Bruchhaus, Iris

    2008-12-01

    Protozoan parasites of the genus Entamoeba possess a considerable number of cysteine peptidases (CPs), the function of most of these molecules for amoeba biology needs to be established. In order to determine whether CPs may play a role during Entamoeba stage conversion from trophozoites into cysts and vice versa, expression of cp genes was analysed in the reptilian parasite Entamoeba invadens, a model organism for studying Entamoeba cyst development. By homology search, 28 papain-like cp genes were identified in public E. invadens genome databases. For eight of these genes the expression profiles during stage conversion was determined. By Northern blot analysis, transcripts for eicp-a9, -b7, -b8 and -c2, respectively, were detected neither in trophozoites or cysts nor at any of the point of times analysed during stage conversion. On the other hand, eicp-a5 is constitutively expressed during all developmental stages, whereas eicp-a3 and eicp-a11, respectively, are trophozoite-specific. Only eicp-b9 was found to be cyst-specific as it is expressed exclusively 18 to 28 h after cyst induction. Cyst-specific expression was confirmed by immunofluorescence microscopy of the corresponding protein EiCP-B9. In immature cysts, the molecule is located in structures that accumulate near the cyst wall, but which are uniformly distributed in mature cysts. The precise function of EiCP-B9 during Entamoeba encystation remains to be determined. However, colocalisation studies with an Entamoeba marker for autophagosomes suggest that EiCP-B9 is not associated with Entamoeba autophagy.

  2. Microbialite genetic diversity and composition relate to environmental variables.

    Science.gov (United States)

    Centeno, Carla M; Legendre, Pierre; Beltrán, Yislem; Alcántara-Hernández, Rocío J; Lidström, Ulrika E; Ashby, Matthew N; Falcón, Luisa I

    2012-12-01

    Microbialites have played an important role in the early history of life on Earth. Their fossilized forms represent the oldest evidence of life on our planet dating back to 3500 Ma. Extant microbialites have been suggested to be highly productive and diverse communities with an evident role in the cycling of major elements, and in contributing to carbonate precipitation. Although their ecological and evolutionary importance has been recognized, the study of their genetic diversity is yet scanty. The main goal of this study was to analyse microbial genetic diversity of microbialites living in different types of environments throughout Mexico, including desert ponds, coastal lagoons and a crater-lake. We followed a pyrosequencing approach of hypervariable regions of the 16S rRNA gene. Results showed that microbialite communities were very diverse (H' = 6-7) and showed geographic variation in composition, as well as an environmental effect related to pH and conductivity, which together explained 33% of the genetic variation. All microbialites had similar proportions of major bacterial and archaeal phyla. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  3. Ageing, longevity, exceptional longevity and related genetic and non genetics markers: panel statement.

    Science.gov (United States)

    Avery, Peter; Barzilai, Nir; Benetos, Athanase; Bilianou, Helen; Capri, Miriam; Caruso, Calogero; Franceschi, Claudio; Katsiki, Niki; Mikhailidis, Dimitri P; Panotopoulos, George; Sikora, Ewa; Tzanetakou, Irene P; Kolovou, Genovefa

    2014-01-01

    In May 2012, a group of scientists and clinicians met in Athens (Greece) to consider the relevance of ageing, longevity, exceptional longevity and related genetic and non genetic markers. During this meeting, we firstly reviewed recent epidemiological and clinical studies on ageing, longevity and exceptional longevity, briefly analyzed the ageing theories and discussed successful and unsuccessful ageing also taking into account the evolutionary perspective. Secondly, we considered the three phenotypes based on the definition of ageing, longevity and exceptional longevity and the associated biomarkers. Third, we discussed proposed treatments suitable to counteract or slow down ageing. Finally, this panel produced a consensus statement to highlight the importance of ageing, longevity and exceptional longevity, since this is a rapidly increasing phenotype worldwide. We acknowledge that not all experts in this field may completely agree with this statement.

  4. Genetic differentiation among sexually compatible relatives of Brassica napus L.

    Directory of Open Access Journals (Sweden)

    Pipan Barbara

    2013-01-01

    Full Text Available Analysis of gene flow between Brassica napus L. and its sexually compatible relatives that could be found in the wild in Slovenia was performed by microsatellite analysis using fifteen selected primer pairs. Genotypes included in the study were obtained from the field survey of sexually compatible relatives of B. napus in natural habitats around Slovenia and from reference collections. Two different wild species of all the presented sexually compatible relatives of B. napus were found in Slovenia, B. rapa and Sinapis arvensis. The reference genotypes included varieties and wild forms from internal collections as marketable seeds or from gene banks. Reference genotypes were represented by the following species and subspecies: B. napus ssp. napobrassica, B. napus ssp. napus, B. nigra, B. oleracea, B. rapa ssp. oleifera, Diplotaxis muralis; D. tenuifolia, Raphanus raphanistrum, R. sativus, R. sativus var. oleiformis, Rapistrum rugosum, S. alba and S. arvensis. Estimation of gene flow described by average number of migrants was 0.72 followed by 0.20 migrants. Due to the observed gene migrations, genetic drift and selection, Hardy-Weinberg equilibrium was not met. The mean number of alleles over all loci was 16.9, the average polymorphic information content was 0.43. We found four highly divergent and polymorphic loci (Na12-C08, Na10-A08, Ni3-G04b and BRMS-050 at statistically significant level (p<0.05 of gene flow detected. Over all gene diversity intra-individual among populations (0.55 was lower than inter-individual among population (0.77. The results of genetic linkages based standard genetic distance and unweighted pair group method with arithmetic mean clustering method, generally divided the genotypes in three divergent groups. Similar results were obtained by principal coordinate analysis where three main groups were constructed according to three factors. A real number of genetic clusters demonstrated a clear separation between populations

  5. Basic Concepts in Molecular Biology Related to Genetics and Epigenetics.

    Science.gov (United States)

    Corella, Dolores; Ordovas, Jose M

    2017-09-01

    The observation that "one size does not fit all" for the prevention and treatment of cardiovascular disease, among other diseases, has driven the concept of precision medicine. The goal of precision medicine is to provide the best-targeted interventions tailored to an individual's genome. The human genome is composed of billions of sequence arrangements containing a code that controls how genes are expressed. This code depends on other nonstatic regulators that surround the DNA and constitute the epigenome. Moreover, environmental factors also play an important role in this complex regulation. This review provides a general perspective on the basic concepts of molecular biology related to genetics and epigenetics and a glossary of key terms. Several examples are given of polymorphisms and genetic risk scores related to cardiovascular risk. Likewise, an overview is presented of the main epigenetic regulators, including DNA methylation, methylcytosine-phosphate-guanine-binding proteins, histone modifications, other histone regulations, micro-RNA effects, and additional emerging regulators. One of the greatest challenges is to understand how environmental factors (diet, physical activity, smoking, etc.) could alter the epigenome, resulting in healthy or unhealthy cardiovascular phenotypes. We discuss some gene-environment interactions and provide a methodological overview. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  6. Glucocorticoid-related genetic susceptibility for Alzheimer's disease.

    Science.gov (United States)

    de Quervain, Dominique J-F; Poirier, Raphael; Wollmer, M Axel; Grimaldi, Luigi M E; Tsolaki, Magdalini; Streffer, Johannes R; Hock, Christoph; Nitsch, Roger M; Mohajeri, M Hasan; Papassotiropoulos, Andreas

    2004-01-01

    Because glucocorticoid excess increases neuronal vulnerability, genetic variations in the glucocorticoid system may be related to the risk for Alzheimer's disease (AD). We analyzed single-nucleotide polymorphisms in 10 glucocorticoid-related genes in a population of 814 AD patients and unrelated control subjects. Set-association analysis revealed that a rare haplotype in the 5' regulatory region of the gene encoding 11beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) was associated with a 6-fold increased risk for sporadic AD. Results of a reporter-gene assay indicated that the rare risk-associated haplotype altered HSD11B1 transcription. HSD11B1 controls tissue levels of biologically active glucocorticoids and thereby influences neuronal vulnerability. Our results indicate that a functional variation in the glucocorticoid system increases the risk for AD, which may have important implications for the diagnosis and treatment of this disease.

  7. RNA interference in Entamoeba histolytica: implications for parasite biology and gene silencing

    Science.gov (United States)

    Zhang, Hanbang; Pompey, Justine M; Singh, Upinder

    2011-01-01

    Entamoeba histolytica is a major health threat to people in developing countries, where it causes invasive diarrhea and liver abscesses. The study of this important human pathogen has been hindered by a lack of tools for genetic manipulation. Recently, a number of genetic approaches based on variations of the RNAi method have been successfully developed and cloning of endogenous small-interfering RNAs from E. histolytica revealed an abundant population of small RNAs with an unusual 5′-polyphosphate structure. However, little is known about the implications of these findings to amebic biology or the mechanisms of gene silencing in this organism. In this article we review the literature relevant to RNAi in E. histolytica, discuss its implications for advances in gene silencing in this organism and outline potential future directions towards understanding the repertoire of RNAi and its impact on the biology of this deep-branching eukaryotic parasite. PMID:21162639

  8. Entamoeba histolytica induces human neutrophils to form NETs.

    Science.gov (United States)

    Ventura-Juarez, J; Campos-Esparza, Mr; Pacheco-Yepez, J; López-Blanco, J A; Adabache-Ortíz, A; Silva-Briano, M; Campos-Rodríguez, R

    2016-08-01

    Entamoeba histolytica invades the intestine and other organs during the pathogenesis of amoebiasis. In the early stages, the host organism responds with an inflammatory infiltrate composed mostly of neutrophils. It has been reported that these immune cells, activated by E. histolytica, exert a protective role by releasing proteolytic enzymes and generating reactive oxygen/nitrogen species (ROS/RNS) and antimicrobial peptides. It is now known that neutrophils also produce neutrophil extracellular traps (NETs), which are able to damage and kill pathogens. Studies have shown that intracellular protozoan pathogens, including Toxoplasma gondi, Plasmodium falciparum and Leishmania spp, induce neutrophils to release NETs and are damaged by them. However, the action of this mechanism has not been explored in relation to E. histolytica trophozoites. Through scanning electron, epifluorescence microscopy and viability assays, we show for first time that during in vitro interaction with E. histolytica trophozoites, human neutrophils released NETs that covered amoebas and reduced amoebic viability. These NETs presented histones, myeloperoxidase and decondensed chromatin. The results suggest that NETs participate in the elimination of the parasite.

  9. Kaempferol inhibits Entamoeba histolytica growth by altering cytoskeletal functions.

    Science.gov (United States)

    Bolaños, Verónica; Díaz-Martínez, Alfredo; Soto, Jacqueline; Marchat, Laurence A; Sanchez-Monroy, Virginia; Ramírez-Moreno, Esther

    2015-11-01

    The flavonoid kaempferol obtained from Helianthemum glomeratum, an endemic Mexican medicinal herb used to treat gastrointestinal disorders, has been shown to inhibit growth of Entamoeba histolytica trophozoites in vitro; however, the mechanisms associated with this activity have not been documented. Several works reported that kaempferol affects cytoskeleton in mammalian cells. In order to gain insights into the action mechanisms involved in the anti-amoebic effect of kaempferol, here we evaluated the effect of this compound on the pathogenic events driven by the cytoskeleton during E. histolytica infection. We also carried out a two dimensional gel-based proteomic analysis to evidence modulated proteins that could explain the phenotypical changes observed in trophozoites. Our results showed that kaempferol produces a dose-dependent effect on trophozoites growth and viability with optimal concentration being 27.7 μM. Kaempferol also decreased adhesion, it increased migration and phagocytic activity, but it did not affect erythrocyte binding nor cytolytic capacity of E. histolytica. Congruently, proteomic analysis revealed that the cytoskeleton proteins actin, myosin II heavy chain and cortexillin II were up-regulated in response to kaempferol treatment. In conclusion, kaempferol anti-amoebic effects were associated with deregulation of proteins related with cytoskeleton, which altered invasion mechanisms.

  10. G protein signaling in the parasite Entamoeba histolytica

    Science.gov (United States)

    Bosch, Dustin E; Siderovski, David P

    2013-01-01

    The parasite Entamoeba histolytica causes amebic colitis and systemic amebiasis. Among the known amebic factors contributing to pathogenesis are signaling pathways involving heterotrimeric and Ras superfamily G proteins. Here, we review the current knowledge of the roles of heterotrimeric G protein subunits, Ras, Rho and Rab GTPase families in E. histolytica pathogenesis, as well as of their downstream signaling effectors and nucleotide cycle regulators. Heterotrimeric G protein signaling likely modulates amebic motility and attachment to and killing of host cells, in part through activation of an RGS-RhoGEF (regulator of G protein signaling–Rho guanine nucleotide exchange factor) effector. Rho family GTPases, as well as RhoGEFs and Rho effectors (formins and p21-activated kinases) regulate the dynamic actin cytoskeleton of E. histolytica and associated pathogenesis-related cellular processes, such as migration, invasion, phagocytosis and evasion of the host immune response by surface receptor capping. A remarkably large family of 91 Rab GTPases has multiple roles in a complex amebic vesicular trafficking system required for phagocytosis and pinocytosis and secretion of known virulence factors, such as amebapores and cysteine proteases. Although much remains to be discovered, recent studies of G protein signaling in E. histolytica have enhanced our understanding of parasitic pathogenesis and have also highlighted possible targets for pharmacological manipulation. PMID:23519208

  11. Virulence parameters in the characterization of strains of Entamoeba histolytica.

    Science.gov (United States)

    Gomes, M A; Melo, M N; Pena, G P; Silva, E F

    1997-01-01

    Differences in virulence of strains of Entamoeba histolytica have long been detected by various experimental assays, both in vivo and in vitro. Discrepancies in the strains characterization have been arisen when different biological assays are compared. In order to evaluate different parameters of virulence in the strains characterization, five strains of E. histolytica, kept under axenic culture, were characterized in respect to their, capability to induce hamster liver abscess, erythrophagocytosis rate and cytopathic effect upon VERO cells. It was found significant correlation between in vitro biological assays, but not between in vivo and in vitro assays. Good correlation was found between cytopathic effect and the mean number of uptaken erythrocytes, but not with percentage of phagocytic amoebae, showing that great variability can be observed in the same assay, according to the variable chosen. It was not possible to correlate isoenzyme and restriction fragment pattern with virulence indexes since all studied strains presented pathogenic patterns. The discordant results observed in different virulence assays suggests that virulence itself may not the directly assessed. What is in fact assessed are different biological characteristics or functions of the parasite more than virulence itself. These characteristics or functions may be related or not with pathogenic mechanisms occurring in the development of invasive amoebic disease.

  12. Comparison of hemolytic activity of the intermediate subunit of Entamoeba histolytica and Entamoeba dispar lectins

    Science.gov (United States)

    Makiuchi, Takashi; Cheng, Xunjia; Tachibana, Hiroshi

    2017-01-01

    Galactose and N-acetyl-D-galactosamine-inhibitable lectin of Entamoeba histolytica has roles in pathogenicity and induction of protective immunity in rodent models of amoebiasis. Recently, the intermediate subunit of the lectin, Igl1, of E. histolytica has been shown to have hemolytic activity. However, the corresponding lectin is also expressed in a non-virulent species, Entamoeba dispar, and another subunit, Igl2, is expressed in the protozoa. Therefore, in this study, we compared the activities of Igl1 and Igl2 subunits from E. histolytica and E. dispar using various regions of recombinant Igl proteins expressed in Escherichia coli. The recombinant E. dispar Igl proteins had comparable hemolytic activities with those of E. histolytica Igl proteins. Furthermore, Igl1 gene-silenced E. histolytica trophozoites showed less hemolytic activity compared with vector-transfected trophozoites, indicating that the expression level of Igl1 protein influences the activity. These results suggest that the lower hemolytic activity in E. dispar compared with E. histolytica reflects the lower expression level of Igl1 in the E. dispar parasite. PMID:28750000

  13. Entamoeba species associated with chronic diarrhoea in Pakistan.

    Science.gov (United States)

    Yakoob, J; Abbas, Z; Beg, M A; Naz, S; Khan, R; Jafri, W

    2012-02-01

    We determined the prevalence of Entamoeba (E.) histolytica, E. dispar and E. moshkovskii in patients with chronic diarrhoea associated with abdominal pain or discomfort mimicking irritable bowel syndrome. Stool samples were collected from 161 patients with chronic diarrhoea and from 157 healthy controls. Stool microscopy with modified trichrome stain, culture and polymerase chain reaction (PCR) for Entamoeba spp. differentiation was performed. Microscopy demonstrated Entamoeba cysts in 44% (57/129) of patients with diarrhoea compared to 29% (44/151) of controls (P=0·009). In patients with diarrhoea, PCR for E. histolytica was positive in 9% (11/129) (P=0·008), E. dispar in 19% (24/129) (P=0·117) and E. moshkovskii in 19% (24/129) (P<0·001). E. histolytica and E. moshkovskii were significantly associated with diarrhoea while E. dispar was found equally in both groups.

  14. Entamoeba histolytica trophozoites transfer lipophosphopeptidoglycans to enteric cell layers.

    Science.gov (United States)

    Lauwaet, Tineke; Oliveira, Maria José; De Bruyne, Georges; Bruchhaus, Iris; Duchêne, Michael; Mareel, Marc; Leroy, Ancy

    2004-04-01

    Transfer of antigens frequently follows adhesion of protozoan parasites to host cells. We were interested in such transfer from the Entamoeba surface to enterocytes following adhesion of trophozoites. Therefore, cocultures of enterocytes in vitro and ex vivo with Entamoeba histolytica (strain HM-1:IMSS) or Entamoeba dispar (strain SAW760) trophozoites were processed for immunocytochemistry. The EH5 monoclonal antibody against amoebic proteophosphoglycans marked a dotted pattern on the apical side of enterocytes in in vitro cocultures with HM-1:IMSS and SAW760 trophozoites. Basolateral staining was present in cocultures following dysfunction of tight junctions, or when trophozoites made direct contact with the basolateral side of enterocytes in in vitro and ex vivo cocultures. Based on the molecular mass in Western blot, the transferred proteophosphoglycan was identified as a lipophosphopeptidoglycan. In conclusion, trophozoites transfer LPPG to the apical side of enterocytes following adhesion and prior to dysfunction of tight junctions.

  15. The cell surface proteome of Entamoeba histolytica.

    Science.gov (United States)

    Biller, Laura; Matthiesen, Jenny; Kühne, Vera; Lotter, Hannelore; Handal, Ghassan; Nozaki, Tomoyoshi; Saito-Nakano, Yumiko; Schümann, Michael; Roeder, Thomas; Tannich, Egbert; Krause, Eberhard; Bruchhaus, Iris

    2014-01-01

    Surface molecules are of major importance for host-parasite interactions. During Entamoeba histolytica infections, these interactions are predicted to be of prime importance for tissue invasion, induction of colitis and liver abscess formation. To date, however, little is known about the molecules involved in these processes, with only about 20 proteins or protein families found exposed on the E. histolytica surface. We have therefore analyzed the complete surface proteome of E. histolytica. Using cell surface biotinylation and mass spectrometry, 693 putative surface-associated proteins were identified. In silico analysis predicted that ∼26% of these proteins are membrane-associated, as they contain transmembrane domains and/or signal sequences, as well as sites of palmitoylation, myristoylation, or prenylation. An additional 25% of the identified proteins likely represent nonclassical secreted proteins. Surprisingly, no membrane-association sites could be predicted for the remaining 49% of the identified proteins. To verify surface localization, 23 proteins were randomly selected and analyzed by immunofluorescence microscopy. Of these 23 proteins, 20 (87%) showed definite surface localization. These findings indicate that a far greater number of E. histolytica proteins than previously supposed are surface-associated, a phenomenon that may be based on the high membrane turnover of E. histolytica.

  16. Trend of Entamoeba histolytica infestation in Kolkata

    Directory of Open Access Journals (Sweden)

    Mukherjee Avik K

    2010-10-01

    Full Text Available Abstract Background Entamoeba histolytica infection is found almost all over the world and is highly endemic and a major cause of parasitic diarrhoea particularly in the developing countries. Methods A systemic surveillance was set up at the Infectious Disease hospital, Kolkata, India between November 2007 and October 2009 for understanding the trend of E. histolytica infection in Kolkata. Fecal samples were collected from diarrhoeal patients attending the hospital, under the surveillance system and processed for detection of E. histolytica. Results During the last two years about 2500 diarrhoeal samples were collected and screened for E. histolytica. About 3.6% were positive for E. histolytica. As compared to the earlier years, E. histolytica infection was observed to be less amongst patients screened during the last two years. No seasonality was observed in Kolkata although in the neighboring tropical country Bangladesh, a typical seasonality of E. histolytica infection was noticed. Conclusion The study indicates that the detection rate of E. histolytica infection amongst diarrhoeal patients in Kolkata is decreasing during the last two years than that of Bangladesh.

  17. [Sensibility of Entamoeba histolytica trophozoites to ivermectin].

    Science.gov (United States)

    González-Salazar, Francisco; Mata-Cárdenas, Benito D; Vargas-Villareal, Javier

    2009-01-01

    Amebiasis caused by Entamoeba histolytica is a problem of public world health. The most frequent clinical presentation are the dysentery and the amebic liver abscess. Fifty millions of cases and more than 100.000 deaths for this disease are reported annually worldwide. The life cycle of E. histolytica has two phases: trophozoite and cyst. Trophozoites are the causal agent of disease. The effective treatment for the amebiasis includes drugs with serious collateral effects. Ivermectin is a macrolid with activity against endoparasites and ectoparasites causing strongiloidosis, filariasis, oncocercosis, scabiasis and pediculosis. The use of ivermectin has been extended almost worldwide; it is recognized as a safe drug. The main objective of this study was to determine in vitro sensibility of trophozoites of E. histolytica was to the treatment with ivermectin. To determine the sensibility of the parasites to the drug, E. histolytica was cultivated in PEHPS medium. During its logarithmic growth phase the trophozoites were exposed to different concentrations of ivermectin. As controls other antiparasitic drugs were used. For each drug, serial dilutions were prepared, and mixed in culture tubes with parasites (2 x 104 cells/ml). They were incubated for 72 h and then the percentage of growth inhibition was calculated by Probit analysis. Ivermectin showed activity against trophozoites of E. histolytica. The 50% of growth inhibition of ivermectin was 6.40 mg/ml. This dose was higher than for other anti parasitic drugs. Its activity in vivo in animal models remains to be demonstrated.

  18. Molecular nature of virulence in Entamoeba histolytica.

    Science.gov (United States)

    Olivos-García, Alfonso; Saavedra, Emma; Ramos-Martínez, Espiridión; Nequiz, Mario; Pérez-Tamayo, Ruy

    2009-12-01

    For many years virulence of pathogenic Entamoeba histolytica has been attributed to the capacity of the parasite to destroy tissues through the expression and/or secretion of various molecules. Such view is supported mainly by in vitro experimentation, whereas data obtained by using animal models of the disease have clearly demonstrated that the host's inflammatory response is primarily responsible for tissue damage. This review analyzes the content and/or activity of some of the presumed toxic amebic molecules present in amebic strains with different degrees of virulence compared to various parasite in vitro functions that are supposed to correlate with in vivo virulence. The analysis suggests that amebic virulence is primarily determined by the parasite's capacity to adapt and survive the aerobic conditions present in animal tissues. This initial episode in the host-parasite relationship is an absolute requirement for the further development of tissue lesions, which result from the concerted action of many molecules derived from both, the host and the parasite.

  19. Thioredoxin-linked metabolism in Entamoeba histolytica.

    Science.gov (United States)

    Arias, Diego G; Gutierrez, César E; Iglesias, Alberto A; Guerrero, Sergio A

    2007-05-15

    Entamoeba histolytica, an intestinal protozoan that is the causative agent of amoebiasis, is exposed to elevated amounts of highly toxic reactive oxygen species during tissue invasion. In this work, we report the molecular cloning, from E. histolytica genomic DNA, of the genes ehtrxr and ehtrx41, respectively coding for thioredoxin reductase (EhTRXR) and thioredoxin (EhTRX41). The genes were expressed in Escherichia coli cells, and the corresponding recombinant proteins were purified and characterized. EhTRXR catalyzed the NADPH (Km=4.5 microM)-dependent reduction of 5,5'-dithiobis-(2-nitrobenzoic) acid (Km=1.7 mM), EhTRX41 (Km=3.6 microM), and E. coli TRX (Km=4.6 microM). EhTRXR and EhTRX41 could be assayed as a functional redox pair that, together with peroxiredoxin, mediate the NADPH-dependent reduction of hydrogen peroxide and tert-butyl hydroperoxide. It is proposed that this detoxifying system could be operative in vivo. Results add value to the genome project information and advise reconsideration of key metabolic pathways operating in E. histolytica.

  20. [Immunochemistry of immunogenic proteins of Entamoeba histolytica].

    Science.gov (United States)

    Marquez, N S; Tamayo, F G; Kumate, J

    1978-01-01

    Entamoeba histolytica (HK-9: IMSS) trophozoites were separated from the culture medium and washed and submitted to the effects of ultrasound during 10 minutes. After 10,000 rpm x 30 centrifugation, the supernatant fluid was separated in four fractions by Sephadex G-200 gel chromatography. These fractions were lyophilized, redisolved in a lesser volume and dyalized against isotonic saline solution. Antigen-antibody precipitant reactions between each of them and two rabbit antiserums were demonstrated: anti amoeba and anti fraction A. It was verified that the antisera reacted also with the culture medium, the human seric albumin and the sera from health people and patients with invasive amebiasis. The higher antigenicity, quantitatively and qualitatively, was obtained with the fraction B; the less antigenic fraction was the fraction D. In fraction A three antigens were identified. When those proteins were filtered by a Bio Gel P4 column, two fractions were eluted: A1 and A2 which were lyophilized, redisolved and dyalized in isotonic saline solution. After this treatment, fraction A1 was capable to maintain its antigenicity against the rabbit antisera and the sera from patients with invasive amebiasis, fact by which it was considered a protein from amebal origin and not as a protenic contaminant from the culture medium.

  1. Characterization of Entamoeba histolytica-induced dephosphorylation in Jurkat cells

    Indian Academy of Sciences (India)

    J E Teixeira; B J Mann

    2002-11-01

    Entamoeba histolytica killing of host cells is contact dependent and mediated by a Gal/GalNAc lectin. Upon contact with amoeba a rapid and extensive dephosphorylation of tyrosine phosphorylated host cell proteins is observed. This effect is mediated by the Gal/GalNAc lectin. However, it requires intact cells, as purified lectin failed to induce dephosphorylation in Jurkat cells. The nonpathogenic, but morphologically identical amoeba, Entamoeba moshkovskii also did not induce dephosphorylation in target cells. Treatment of Jurkat cells with phosphotyrosine phosphatase inhibitors has shown that a host phosphatase is responsible for dephosphorylation. However, it was found that the CD45 phosphotase was not necessary for dephosphorylation of host cell proteins.

  2. The Double Helix: Applying an Ethic of Care to the Duty to Warn Genetic Relatives of Genetic Information.

    Science.gov (United States)

    Weaver, Meaghann

    2016-03-01

    Genetic testing reveals information about a patient's health status and predictions about the patient's future wellness, while also potentially disclosing health information relevant to other family members. With the increasing availability and affordability of genetic testing and the integration of genetics into mainstream medicine, the importance of clarifying the scope of confidentiality and the rules regarding disclosure of genetic findings to genetic relatives is prime. The United Nations International Declaration on Human Genetic Data urges an appreciation for principles of equality, justice, solidarity and responsibility in the context of genetic testing, including a commitment to honoring the privacy and security of the person tested. Considering this global mandate and recent professional statements in the context of a legal amendment to patient privacy policies in Australia, a fresh scrutiny of the legal history of a physician's duty to warn is warranted. This article inquiries whether there may be anything ethically or socially amiss with a potential future recommendation for health professionals or patients to universally disclose particular cancer predisposition genetic diagnosis to genetic family members. While much of the discussion remains applicable to all genetic diagnosis, the article focuses on the practice of disclosure within the context of BRCA1/2 diagnosis. An 'ethic of care' interpretation of legal tradition and current practice will serve to reconcile law and medical policy on the issue of physician disclosure of genetic results to family members without patient consent. © 2015 John Wiley & Sons Ltd.

  3. Patient autonomy and relatives' right to know genetic information.

    Science.gov (United States)

    Gilbar, Roy

    2007-12-01

    One of the most difficult issues doctors face is a conflict between their professional duties. Such a conflict may arise when doctors know that information has implications not only for patients but also for family members but their duty of confidentiality prevents them from disclosing it. A comparative analysis of English and Israeli medical law reveals that the doctors' duty is based on two principles: a liberal perception of patient autonomy and an overriding utilitarian principle of prevention of harm. However, socio-medical research indicates that these principles do not entirely reflect the views of patients and doctors and are too narrow to deal with the complex situations in practice. Thus, it is argued that the doctor's legal duty of confidentiality should be reconsidered and qualified when it concerns the family. It is suggested that if medical law seeks to recognize the various interests family members have in genetic information then we should consider a different approach, founded on a relational interpretation of autonomy and communitarian notions of solidarity and moral responsibility. This approach perceives confidentiality and privacy as embracing the family unit, based on the view that close relatives are not entirely outside the private sphere of the individual but rather are integral to his or her identity. Thus, to the utilitarian mechanism available in medical law this approach adds a social criterion: The effect any decision (to disclose or not to disclose) will have on the familial relationship and on the dynamics of the particular family. This will provide a more flexible and workable alternative for doctors to resolve familial tensions over access to genetic information.

  4. On the relation between gene flow theory and genetic gain

    Directory of Open Access Journals (Sweden)

    Woolliams John A

    2000-01-01

    Full Text Available Abstract In conventional gene flow theory the rate of genetic gain is calculated as the summed products of genetic selection differential and asymptotic proportion of genes deriving from sex-age groups. Recent studies have shown that asymptotic proportions of genes predicted from conventional gene flow theory may deviate considerably from true proportions. However, the rate of genetic gain predicted from conventional gene flow theory was accurate. The current note shows that the connection between asymptotic proportions of genes and rate of genetic gain that is embodied in conventional gene flow theory is invalid, even though genetic gain may be predicted correctly from it.

  5. Glucose starvation boosts Entamoeba histolytica virulence.

    Directory of Open Access Journals (Sweden)

    Ayala Tovy

    2011-08-01

    Full Text Available The unicellular parasite, Entamoeba histolytica, is exposed to numerous adverse conditions, such as nutrient deprivation, during its life cycle stages in the human host. In the present study, we examined whether the parasite virulence could be influenced by glucose starvation (GS. The migratory behaviour of the parasite and its capability to kill mammalian cells and to lyse erythrocytes is strongly enhanced following GS. In order to gain insights into the mechanism underlying the GS boosting effects on virulence, we analyzed differences in protein expression levels in control and glucose-starved trophozoites, by quantitative proteomic analysis. We observed that upstream regulatory element 3-binding protein (URE3-BP, a transcription factor that modulates E.histolytica virulence, and the lysine-rich protein 1 (KRiP1 which is induced during liver abscess development, are upregulated by GS. We also analyzed E. histolytica membrane fractions and noticed that the Gal/GalNAc lectin light subunit LgL1 is up-regulated by GS. Surprisingly, amoebapore A (Ap-A and cysteine proteinase A5 (CP-A5, two important E. histolytica virulence factors, were strongly down-regulated by GS. While the boosting effect of GS on E. histolytica virulence was conserved in strains silenced for Ap-A and CP-A5, it was lost in LgL1 and in KRiP1 down-regulated strains. These data emphasize the unexpected role of GS in the modulation of E.histolytica virulence and the involvement of KRiP1 and Lgl1 in this phenomenon.

  6. Genetics Home Reference: 6q24-related transient neonatal diabetes mellitus

    Science.gov (United States)

    ... Facebook Share on Twitter Your Guide to Understanding Genetic Conditions Search MENU Toggle navigation Home Page Search ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions 6q24-related transient neonatal diabetes ...

  7. Species-Specific Immunodetection of an Entamoeba histolytica Cyst Wall Protein.

    Science.gov (United States)

    Spadafora, Lauren J; Kearney, Moira R; Siddique, Abdullah; Ali, Ibne K; Gilchrist, Carol A; Arju, Tuhinur; Hoffstrom, Benjamin; Nguyen, Felicia K; Petri, William A; Haque, Rashidul; Cangelosi, Gerard A

    2016-05-01

    Entamoeba histolytica causes intestinal disease in endemic settings throughout the world. Diagnosis of E. histolytica infection would be improved by the identification of biomarkers that are expressed by cysts of E. histolytica, but not by cysts of closely related commensal species of Entamoeba. Herein, we describe two novel monoclonal antibodies (1A4 and 1D3) produced against a spacer region of the E. histolytica Jacob2 lectin, an outer cyst wall protein. These reagents demonstrated no cross-reaction to E. dispar recombinant antigen and low picomolar molecular detection limits when paired in ELISA sandwich assays. In an immunofluorescence microscopy assay, the α-Jacob2 murine antibodies labeled cysts of three xenically cultured E. histolytica isolates but did not label cysts of three E. bangladeshi isolates. Monoclonal antibody 1A4 did not cross-react with xenic cultures of three E. dispar isolates, demonstrating specificity to E. histolytica, while monoclonal antibody 1D3 cross-reacted with two out of three E. dispar isolates. Both antibodies labeled cysts in formalin-fixed slides, a potential logistical advantage in some settings. The monoclonal antibody 1A4 was also used in an immunofluorescence microscopy assay with formalin-fixed stool specimens. Seven out of ten ELISA-positive stool specimens exhibited 1A4-labeled cyst-like objects, compared to one out of seven ELISA-negative specimens. These results demonstrate that antibodies generated against the flexible spacer of E. histolytica Jacob2 lectin recognize and bind to Jacob2 protein in whole cysts and are capable of differentiating Entamoeba species in fixed specimens. Thus, Jacob2 is a promising biomarker for use in diagnosing E. histolytica infection.

  8. Knockdown of Five Genes Encoding Uncharacterized Proteins Inhibits Entamoeba histolytica Phagocytosis of Dead Host Cells.

    Science.gov (United States)

    Sateriale, Adam; Miller, Peter; Huston, Christopher D

    2016-04-01

    Entamoeba histolytica is the protozoan parasite that causes invasive amebiasis, which is endemic to many developing countries and characterized by dysentery and liver abscesses. The virulence of E. histolytica correlates with the degree of host cell engulfment, or phagocytosis, and E. histolytica phagocytosis alters amebic gene expression in a feed-forward manner that results in an increased phagocytic ability. Here, we used a streamlined RNA interference screen to silence the expression of 15 genes whose expression was upregulated in phagocytic E. histolytica trophozoites to determine whether these genes actually function in the phagocytic process. When five of these genes were silenced, amebic strains with significant decreases in the ability to phagocytose apoptotic host cells were produced. Phagocytosis of live host cells, however, was largely unchanged, and the defects were surprisingly specific for phagocytosis. Two of the five encoded proteins, which we named E. histolytica ILWEQ (EhILWEQ) and E. histolytica BAR (EhBAR), were chosen for localization via SNAP tag labeling and localized to the site of partially formed phagosomes. Therefore, both EhILWEQ and EhBAR appear to contribute to E. histolytica virulence through their function in phagocytosis, and the large proportion (5/15 [33%]) of gene-silenced strains with a reduced ability to phagocytose host cells validates the previously published microarray data set demonstrating feed-forward control of E. histolytica phagocytosis. Finally, although only limited conclusions can be drawn from studies using the virulence-deficient G3 Entamoeba strain, the relative specificity of the defects induced for phagocytosis of apoptotic cells but not healthy cells suggests that cell killing may play a rate-limiting role in the process of Entamoeba histolytica host cell engulfment.

  9. Knockdown of Five Genes Encoding Uncharacterized Proteins Inhibits Entamoeba histolytica Phagocytosis of Dead Host Cells

    Science.gov (United States)

    Sateriale, Adam; Miller, Peter

    2016-01-01

    Entamoeba histolytica is the protozoan parasite that causes invasive amebiasis, which is endemic to many developing countries and characterized by dysentery and liver abscesses. The virulence of E. histolytica correlates with the degree of host cell engulfment, or phagocytosis, and E. histolytica phagocytosis alters amebic gene expression in a feed-forward manner that results in an increased phagocytic ability. Here, we used a streamlined RNA interference screen to silence the expression of 15 genes whose expression was upregulated in phagocytic E. histolytica trophozoites to determine whether these genes actually function in the phagocytic process. When five of these genes were silenced, amebic strains with significant decreases in the ability to phagocytose apoptotic host cells were produced. Phagocytosis of live host cells, however, was largely unchanged, and the defects were surprisingly specific for phagocytosis. Two of the five encoded proteins, which we named E. histolytica ILWEQ (EhILWEQ) and E. histolytica BAR (EhBAR), were chosen for localization via SNAP tag labeling and localized to the site of partially formed phagosomes. Therefore, both EhILWEQ and EhBAR appear to contribute to E. histolytica virulence through their function in phagocytosis, and the large proportion (5/15 [33%]) of gene-silenced strains with a reduced ability to phagocytose host cells validates the previously published microarray data set demonstrating feed-forward control of E. histolytica phagocytosis. Finally, although only limited conclusions can be drawn from studies using the virulence-deficient G3 Entamoeba strain, the relative specificity of the defects induced for phagocytosis of apoptotic cells but not healthy cells suggests that cell killing may play a rate-limiting role in the process of Entamoeba histolytica host cell engulfment. PMID:26810036

  10. Entamoeba Clone-Recognition Experiments: Morphometrics, Aggregative Behavior, and Cell-Signaling Characterization.

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    Espinosa, Avelina; Paz-Y-Miño-C, Guillermo; Hackey, Meagan; Rutherford, Scott

    2016-05-01

    Studies on clone- and kin-discrimination in protists have proliferated during the past decade. We report clone-recognition experiments in seven Entamoeba lineages (E. invadens IP-1, E. invadens VK-1:NS, E. terrapinae, E. moshkovskii Laredo, E. moshkovskii Snake, E. histolytica HM-1:IMSS and E. dispar). First, we characterized morphometrically each clone (length, width, and cell-surface area) and documented how they differed statistically from one another (as per single-variable or canonical-discriminant analyses). Second, we demonstrated that amebas themselves could discriminate self (clone) from different (themselves vs. other clones). In mix-cell-line cultures between closely-related (E. invadens IP-1 vs. E. invadens VK-1:NS) or distant-phylogenetic clones (E. terrapinae vs. E. moshkovskii Laredo), amebas consistently aggregated with same-clone members. Third, we identified six putative cell-signals secreted by the amebas (RasGap/Ankyrin, coronin-WD40, actin, protein kinases, heat shock 70, and ubiquitin) and which known functions in Entamoeba spp. included: cell proliferation, cell adhesion, cell movement, and stress-induced encystation. To our knowledge, this is the first multi-clone characterization of Entamoeba spp. morphometrics, aggregative behavior, and cell-signaling secretion in the context of clone-recognition. Protists allow us to study cell-cell recognition from ecological and evolutionary perspectives. Modern protistan lineages can be central to studies about the origins and evolution of multicellularity.

  11. Regulation of gene expression in the protozoan parasite Entamoeba invadens: identification of core promoter elements and promoters with stage-specific expression patterns.

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    Manna, Dipak; Ehrenkaufer, Gretchen M; Singh, Upinder

    2014-10-01

    Developmental switching between life-cycle stages is a common feature among many pathogenic organisms. Entamoeba histolytica is an important human pathogen and is a leading parasitic cause of death globally. During its life cycle, Entamoeba converts between cysts (essential for disease transmission) and trophozoites (responsible for tissue invasion). Despite being central to its biology, the triggers that are involved in the developmental pathways of this parasite are not well understood. In order to define the transcriptional network associated with stage conversion we used Entamoeba invadens which serves as a model system for Entamoeba developmental biology, and performed RNA sequencing at different developmental time points. In this study RNA-Seq data was utilised to define basal transcriptional control elements as well as to identify promoters which regulate stage-specific gene expression patterns. We discovered that the 5' and 3' untranslated regions of E. invadens genes are short, a median of 20 nucleotides (nt) and 26 nt respectively. Bioinformatics analysis of DNA sequences proximate to the start and stop codons identified two conserved motifs: (i) E. invadens Core Promoter Motif - GAAC-Like (EiCPM-GL) (GAACTACAAA), and (ii) E. invadens 3'-U-Rich Motif (Ei3'-URM) (TTTGTT) in the 5' and 3' flanking regions, respectively. Electrophoretic mobility shift assays demonstrated that both motifs specifically bind nuclear protein(s) from E. invadens trophozoites. Additionally, we identified select genes with stage-specific expression patterns and analysed the ability of each gene promoter to drive a luciferase reporter gene during the developmental cycle. This approach confirmed three trophozoite-specific, four encystation-specific and two excystation-specific promoters. This work lays the framework for use of stage-specific promoters to express proteins of interest in a particular life-cycle stage, adding to the molecular toolbox for genetic manipulation of E

  12. Molecular detection of Entamoeba histolytica and Entamoeba dispar infection among wild rats in Kuala Lumpur, Malaysia.

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    Lau, Y L; Jamaiah, I; Rohela, M; Fong, M Y; Siti, C O S; Siti, F A

    2014-12-01

    Entamoeba histolytica infection is the third-greatest parasitic disease responsible for death in the world. Wild rats harbouring E. histolytica can be the possible reservoir hosts for human amoebiasis. There were numerous studies on prevalence of intestinal parasites among wild rats in Malaysia but none has reported E. histolytica. Rats were captured from Sentul and Chow Kit areas, Kuala Lumpur, Malaysia. The preserved stool samples were used for microscopy examination and molecular analysis. Out of 137 samples collected, 12 were positive for E. histolytica / E. dispar / E. moshkovskii microscopically. Two E. histolytica (1.4%), 1 E. dispar (0.7%) and 6 mixed infections of E. histolytica and E. dispar (4.3%) were detected using PCR. This is the first report of molecular detection of E. histolytica/dispar infection among wild rats in Malaysia. This study provides useful information about the potential risks of zoonotic agents and the importance of developing control measures to prevent zoonotic transmission.

  13. Giardia, Entamoeba, and Trichomonas enzymes activate metronidazole (nitroreductases) and inactivate metronidazole (nitroimidazole reductases).

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    Pal, Dibyarupa; Banerjee, Sulagna; Cui, Jike; Schwartz, Aaron; Ghosh, Sudip K; Samuelson, John

    2009-02-01

    Infections with Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis, which cause diarrhea, dysentery, and vaginitis, respectively, are each treated with metronidazole. Here we show that Giardia, Entamoeba, and Trichomonas have oxygen-insensitive nitroreductase (ntr) genes which are homologous to those genes that have nonsense mutations in metronidazole-resistant Helicobacter pylori isolates. Entamoeba and Trichomonas also have nim genes which are homologous to those genes expressed in metronidazole-resistant Bacteroides fragilis isolates. Recombinant Giardia, Entamoeba, and Trichomonas nitroreductases used NADH rather than the NADPH used by Helicobacter, and two recombinant Entamoeba nitroreductases increased the metronidazole sensitivity of transformed Escherichia coli strains. Conversely, the recombinant nitroimidazole reductases (NIMs) of Entamoeba and Trichmonas conferred very strong metronidazole resistance to transformed bacteria. The Ehntr1 gene of the genome project HM-1:IMSS strain of Entamoeba histolytica had a nonsense mutation, and the same nonsense mutation was present in 3 of 22 clinical isolates of Entamoeba. While ntr and nim mRNAs were variably expressed by cultured Entamoeba and Trichomonas isolates, there was no relationship to metronidazole sensitivity. We conclude that microaerophilic protists have bacterium-like enzymes capable of activating metronidazole (nitroreductases) and inactivating metronidazole (NIMs). While Entamoeba and Trichomonas displayed some of the changes (nonsense mutations and gene overexpression) associated with metronidazole resistance in bacteria, these changes did not confer metronidazole resistance to the microaerophilic protists examined here.

  14. High prevalence of Entamoeba infections in captive long-tailed macaques in China.

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    Feng, Meng; Yang, Bin; Yang, Liu; Fu, Yongfeng; Zhuang, Yijun; Liang, Longgan; Xu, Qing; Cheng, Xunjia; Tachibana, Hiroshi

    2011-10-01

    Long-tailed macaques (Macaca fascicularis) are bred in China for export and for use in experiments. Entamoeba infections in captive long-tailed macaques were surveyed in one of the biggest colonies located in Guangxi Province, China. One stool sample was obtained from each of the 152 different cages representing >3,000 macaques in the colony. The samples were examined by PCR for five Entamoeba species. The number of detected Entamoeba coli infections comprised 94% of the samples, 93% for Entamoeba chattoni, and 83% for Entamoeba dispar. In contrast, Entamoeba histolytica and Entamoeba nuttalli were not detected. Six isolates of E. dispar were obtained by culture in Tanabe-Chiba medium. Analysis of serine-rich protein genes in these isolates showed two genotypes, one of which is identical to that of the E. dispar SAW760 strain in humans. This suggests transmission of E. dispar between humans and nonhuman primates. These results demonstrate that Entamoeba infections are common, but virulent Entamoeba species are absent in this colony. This work also confirms the need for monitoring with PCR-based identification of Entamoeba species for captive macaques in breeding colonies to ensure animal health and protection of humans from zoonotic hazards.

  15. Radioimmunoprecipitation polyethylene glycol assay for circulating Entamoeba histolytica antigens

    Energy Technology Data Exchange (ETDEWEB)

    Pillai, S.; Mohimen, A.; Mehra, S. (Calcutta Medical Research Inst., Calcutta (India). Kothari Centre of Gastroenterology)

    1982-12-17

    An assay capable of detecting circulating Entamoeba histolytica antigens in amoebiasis is described. This assay utilised a radiolabelled affinity purified rabbit anti-E. histolytica antibody that had been depleted of antibodies that cross-react with human serum proteins, and a polyethylene glycol precipitation step.

  16. MALDI-TOF mass spectrometry for the detection and differentiation of Entamoeba histolytica and Entamoeba dispar.

    Science.gov (United States)

    Calderaro, Adriana; Piergianni, Maddalena; Buttrini, Mirko; Montecchini, Sara; Piccolo, Giovanna; Gorrini, Chiara; Rossi, Sabina; Chezzi, Carlo; Arcangeletti, Maria Cristina; Medici, Maria Cristina; De Conto, Flora

    2015-01-01

    Detection of Entamoeba histolytica and its differentiation from Entamoeba dispar is an important goal of the clinical parasitology laboratory. The aim of this study was the identification and differentiation of E. histolytica and E. dispar by MALDI-TOF MS, in order to evaluate the application of this technique in routine diagnostic practice. MALDI-TOF MS was applied to 3 amebic reference strains and to 14 strains isolated from feces that had been differentiated by molecular methods in our laboratory. Protein extracts from cultures of these strains (axenic cultures for the 3 reference strains and monoxenic cultures for the 14 field isolates) were analyzed by MALDI-TOF MS and the spectra obtained were analyzed by statistical software. Five peaks discriminating between E. histolytica and E. dispar reference strains were found by protein profile analysis: 2 peaks (8,246 and 8,303 Da) specific for E. histolytica and 3 (4,714; 5,541; 8,207 Da) for E. dispar. All clinical isolates except one showed the discriminating peaks expected for the appropriate species. For 2 fecal samples from which 2 strains (1 E. histolytica and 1 E. dispar) out of the 14 included in this study were isolated, the same discriminating peaks found in the corresponding isolated amebic strains were detected after only 12h (E. histolytica) and 24h (E. dispar) of incubation of the fecal samples in Robinson's medium without serum. Our study shows that MALDI-TOF MS can be used to discriminate between E. histolytica and E. dispar using in vitro xenic cultures and it also could have potential for the detection of these species in clinical samples.

  17. MALDI-TOF mass spectrometry for the detection and differentiation of Entamoeba histolytica and Entamoeba dispar.

    Directory of Open Access Journals (Sweden)

    Adriana Calderaro

    Full Text Available Detection of Entamoeba histolytica and its differentiation from Entamoeba dispar is an important goal of the clinical parasitology laboratory. The aim of this study was the identification and differentiation of E. histolytica and E. dispar by MALDI-TOF MS, in order to evaluate the application of this technique in routine diagnostic practice. MALDI-TOF MS was applied to 3 amebic reference strains and to 14 strains isolated from feces that had been differentiated by molecular methods in our laboratory. Protein extracts from cultures of these strains (axenic cultures for the 3 reference strains and monoxenic cultures for the 14 field isolates were analyzed by MALDI-TOF MS and the spectra obtained were analyzed by statistical software. Five peaks discriminating between E. histolytica and E. dispar reference strains were found by protein profile analysis: 2 peaks (8,246 and 8,303 Da specific for E. histolytica and 3 (4,714; 5,541; 8,207 Da for E. dispar. All clinical isolates except one showed the discriminating peaks expected for the appropriate species. For 2 fecal samples from which 2 strains (1 E. histolytica and 1 E. dispar out of the 14 included in this study were isolated, the same discriminating peaks found in the corresponding isolated amebic strains were detected after only 12h (E. histolytica and 24h (E. dispar of incubation of the fecal samples in Robinson's medium without serum. Our study shows that MALDI-TOF MS can be used to discriminate between E. histolytica and E. dispar using in vitro xenic cultures and it also could have potential for the detection of these species in clinical samples.

  18. MALDI-TOF Mass Spectrometry for the Detection and Differentiation of Entamoeba histolytica and Entamoeba dispar

    Science.gov (United States)

    Calderaro, Adriana; Piergianni, Maddalena; Buttrini, Mirko; Montecchini, Sara; Piccolo, Giovanna; Gorrini, Chiara; Rossi, Sabina; Chezzi, Carlo; Arcangeletti, Maria Cristina; Medici, Maria Cristina; De Conto, Flora

    2015-01-01

    Detection of Entamoeba histolytica and its differentiation from Entamoeba dispar is an important goal of the clinical parasitology laboratory. The aim of this study was the identification and differentiation of E. histolytica and E. dispar by MALDI-TOF MS, in order to evaluate the application of this technique in routine diagnostic practice. MALDI-TOF MS was applied to 3 amebic reference strains and to 14 strains isolated from feces that had been differentiated by molecular methods in our laboratory. Protein extracts from cultures of these strains (axenic cultures for the 3 reference strains and monoxenic cultures for the 14 field isolates) were analyzed by MALDI-TOF MS and the spectra obtained were analyzed by statistical software. Five peaks discriminating between E. histolytica and E. dispar reference strains were found by protein profile analysis: 2 peaks (8,246 and 8,303 Da) specific for E. histolytica and 3 (4,714; 5,541; 8,207 Da) for E. dispar. All clinical isolates except one showed the discriminating peaks expected for the appropriate species. For 2 fecal samples from which 2 strains (1 E. histolytica and 1 E. dispar) out of the 14 included in this study were isolated, the same discriminating peaks found in the corresponding isolated amebic strains were detected after only 12h (E. histolytica) and 24h (E. dispar) of incubation of the fecal samples in Robinson’s medium without serum. Our study shows that MALDI-TOF MS can be used to discriminate between E. histolytica and E. dispar using in vitro xenic cultures and it also could have potential for the detection of these species in clinical samples. PMID:25874612

  19. Differential detection of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii in fecal samples by nested PCR in the United Arab Emirates (UAE).

    Science.gov (United States)

    ElBakri, Ali; Samie, Amidou; Ezzedine, Sinda; Odeh, Raed Abu

    2013-06-01

    Amoebiasis is one of the most important infectious diseases afflicting mainly tropical and subtropical countries. This study was carried out in the Sharjah Emirate, UAE in order to accurately detect and differentiate Entamoeba histolytica, Entamoeba dispar and E. moshkovskii in fecal samples collected from the Sharjah municipality public health clinic by ELISA and nested polymerase chain reaction (PCR). One hundred and twenty specimens were examined and the PCR was positive for E. histolytica, E. dispar and E. moshkovskii (collectively referred to as Entamoeba complex) in 19.2% (23 out of 120). Of those, 10% (12/120) were mono - infection with E. histolytica; 2.5% (3/120) with E. dispar; and 2.5% (3/120) E. moshkovskii. The nested PCR also detected mixed infections by both E. histolytica and E. dispar in 3.3% (4/120) and E. dispar and E. moshkovskii in 0.8% (1/120). The TechLab ELISA kit failed to detect E. histolytica in any of the E. histolytica PCR positive samples. Overall, the percentage of E. histolytica including those found in mixed infections was 13.3% (16/120). Compared to nested PCR, microscopy was found to have an overall sensitivity of 52.2% and a specificity of 75.2% for detection of Entamoeba complex. The present study indicates that E. histolytica is present in the UAE with an average incidence rate of 13.3%. However, larger studies need to be conducted in order to confirm these findings. We propose the use of PCR in both the routine diagnosis of amoebiasis and epidemiological survey in the UAE.

  20. Morphometric study of the hepatic lesions experimentally induced in hamsters by Entamoeba dispar and E. histolytica

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    Costa C.A.X.

    2007-12-01

    Full Text Available Evolution of experimental hepatic lesions produced in hamsters with Entamoeba histolytica and E. dispar was evaluated quantitatively and qualitatively through morphometry and immunohistochemistry. Animals infected with E. dispar developed hepatic lesions quantitatively and qualitatively similar to those produced by E. histolytica on the first three days of infection. On the 6th and 8th days of infection, E. histolytica produced larger tissue damage than E. dispar. A gradual decrease was observed in the number of trophozoites along the infection. A negative correlation was observed between the reduced number of trophozoites and the larger area of necrosis in both groups, confirming the importance of trophozoites killed in the lesion genesis. Regarding the genetic similarity between E. histolytica and E. dispar, comparison strategy between lesions produced by these species may culminate in identifying virulence factors of E. histolytica.

  1. Evaluation of a new single-tube multiprobe real-time PCR for diagnosis of Entamoeba histolytica and Entamoeba dispar.

    Science.gov (United States)

    Liang, Shih-Yu; Hsia, Kan-Tai; Chan, Yun-Hsien; Fan, Chia-Kwung; Jiang, Donald Dah-Shyong; Landt, Olfert; Ji, Dar-Der

    2010-08-01

    A single-tube multiprobe real-time PCR assay for simultaneous detection of Entamoeba histolytica and Entamoeba dispar was developed. One primer pair with 2 species-specific probes was designed based on new SSU RNA regions of the ribosomal DNA-containing episome. The sensitivity is 1 parasite per milliliter of feces and thus superior to the conventional nested PCR and comparable to other published real-time PCR protocols. The applicability for clinical diagnosis was validated with 218 stool specimens from patients. A total of 51 E. histolytica and 39 E. dispar positive samples was detected by the multiprobe real-time PCR compared to 39 and 22 by routine nested PCR diagnosis. The detection rate of Entamoeba species for the multiprobe real-time PCR assays was significantly higher than the nested PCR (40.8% vs. 28.0%, P Entamoeba moshkovskii, Giardia lamblia , Cryptosporidium sp., Escherichia coli , or other nonpathogenic enteric parasites. The multiprobe real-time PCR assay is simple and rapid and has high specificity and sensitivity. The assay could streamline the laboratory diagnosis procedure and facilitate epidemiological investigation.

  2. [Differentiation of Entamoeba histolytica from Entamoeba dispar using Gal/GalNAc-lectin and polymerase chain reaction].

    Science.gov (United States)

    López, Omaira Y; López, Myriam C; Corredor, Vladimir; Echeverri, M Clara; Pinilla, Análida E

    2012-04-01

    Entamoeba histolytica and Entamoeba dispar are morphologically identical. However, the former is highly pathogenic and the latter is not. To differentiate Entamoeba histolytica from Entamoeba dispar through ELISA and PCR techniques in Colombian isolates from feces. Descriptive study of Colombian fecal samples from 53 males and 47 women, that were positive for the complex E. histolytica/E. dispar on light microscopy. Positive samples were cultured on Robinson medium to isolate trophozoites. The presence of specific Gal/ GalNAc-lectin was determined by ELISA and polymerase chain reaction in genomic DNA, using the combination of three nucleotides that recognize a variable region of 16S small subunit ribosomal RNA, generating a 166 base pair (bp) product for E. histolytica and 752 pb product for E. dispar. After verification, only eight of the 100 samples were positive for the complex E. histolytica/E. dispar and were cultivated. Isolates were obtained in six cultures, one corresponded to E. histolytica and six to E. dispar. The presence of E. histolytica/E. dispar complex was largely overestimated with light microscopy. In the few samples where isolates were obtained, the technique described differentiated between both strains.

  3. The genetic and environmental etiologies of the relations between cognitive skills and components of reading ability.

    Science.gov (United States)

    Christopher, Micaela E; Keenan, Janice M; Hulslander, Jacqueline; DeFries, John C; Miyake, Akira; Wadsworth, Sally J; Willcutt, Erik; Pennington, Bruce; Olson, Richard K

    2016-04-01

    Although previous research has shown cognitive skills to be important predictors of reading ability in children, the respective roles for genetic and environmental influences on these relations is an open question. The present study explored the genetic and environmental etiologies underlying the relations between selected executive functions and cognitive abilities (working memory, inhibition, processing speed, and naming speed) with 3 components of reading ability (word reading, reading comprehension, and listening comprehension). Twin pairs drawn from the Colorado Front Range (n = 676; 224 monozygotic pairs; 452 dizygotic pairs) between the ages of 8 and 16 (M = 11.11) were assessed on multiple measures of each cognitive and reading-related skill. Each cognitive and reading-related skill was modeled as a latent variable, and behavioral genetic analyses estimated the portions of phenotypic variance on each latent variable due to genetic, shared environmental, and nonshared environmental influences. The covariance between the cognitive skills and reading-related skills was driven primarily by genetic influences. The cognitive skills also shared large amounts of genetic variance, as did the reading-related skills. The common cognitive genetic variance was highly correlated with the common reading genetic variance, suggesting that genetic influences involved in general cognitive processing are also important for reading ability. Skill-specific genetic variance in working memory and processing speed also predicted components of reading ability. Taken together, the present study supports a genetic association between children's cognitive ability and reading ability.

  4. A Toll/IL-1R/resistance domain-containing thioredoxin regulates phagocytosis in Entamoeba histolytica

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    Mancilla-Herrera Ismael

    2012-10-01

    Full Text Available Abstract Background Entamoeba histolytica is a protozoan parasite that infects humans and causes amebiasis affecting developing countries. Phagocytosis of epithelial cells, erythrocytes, leucocytes, and commensal microbiota bacteria is a major pathogenic mechanism used by this parasite. A Toll/IL-1R/Resistance (TIR domain-containing protein is required in phagocytosis in the social ameba Dictyostelium discoideum, an ameba closely related to Entamoeba histolytica in phylogeny. In insects and vertebrates, TIR domain-containing proteins regulate phagocytic and cell activation. Therefore, we investigated whether E. histolytica expresses TIR domain-containing molecules that may be involved in the phagocytosis of erythrocytes and bacteria. Methods Using in silico analysis we explored in Entamoeba histolytica databases for TIR domain containing sequences. After silencing TIR domain containing sequences in trophozoites by siRNA we evaluated phagocytosis of erythrocytes and bacteria. Results We identified an E. histolytica thioredoxin containing a TIR-like domain. The secondary and tertiary structure of this sequence exhibited structural similarity to TIR domain family. Thioredoxin transcripts silenced in E. histolytica trophozoites decreased erythrocytes and E. coli phagocytosis. Conclusion TIR domain-containing thioredoxin of E. histolytica could be an important element in erythrocytes and bacteria phagocytosis.

  5. Identification and delineation of members of the Entamoeba complex by pyrosequencing.

    Science.gov (United States)

    Stensvold, Christen R; Lebbad, Marianne; Verweij, Jaco J; Jespersgaard, Cathrine; von Samson-Himmelstjerna, Georg; Nielsen, Susanne S; Nielsen, Henrik V

    2010-12-01

    A method using a single-round PCR coupled to pyrosequencing was developed for the detection and differentiation of members of the Entamoeba complex. The technique was evaluated using DNA isolated directly from faecal specimens and compared with a duplex real-time PCR targeting Entamoeba histolytica and Entamoeba dispar, and a conventional single-round PCR for the detection of Entamoeba moshkovskii. Tetranucleate cysts from 102 faecal specimens from Swedish, Danish and Dutch patients test-positive for the Entamoeba complex by coproscopic examination were identified to species using each of the three methods. Although none of the patients were confirmed to be positive for E. moshkovskii, E. histolytica and E. dispar were identified in 17 and 86 of the samples, respectively, one of the samples containing both species. There was concordance in results between pyrosequencing and the two other methods used. This study showed that PCR and pyrosequencing could be used for the rapid and high throughput identification of Entamoeba species.

  6. Genetics Home Reference: GRN-related frontotemporal dementia

    Science.gov (United States)

    ... Neumann M, Kwong LK, Trojanowski JQ, Lee VM, Grossman M. Clinical, genetic, and pathologic characteristics of patients ... Feldman H, Woltjer R, Miller CA, Wood EM, Grossman M, McCluskey L, Clark CM, Neumann M, Danek ...

  7. Virulence parameters in the characterization of strains of Entamoeba histolytica

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    Maria A GOMES

    1997-03-01

    Full Text Available Differences in virulence of strains of Entamoeba histolytica have long been detected by various experimental assays, both in vivo and in vitro. Discrepancies in the strains characterization have been arisen when different biological assays are compared. In order to evaluate different parameters of virulence in the strains characterization, five strains of E. histolytica, kept under axenic culture, were characterized in respect to their, capability to induce hamster liver abscess, erythrophagocytosis rate and cytopathic effect upon VERO cells. It was found significant correlation between in vitro biological assays, but not between in vivo and in vitro assays. Good correlation was found between cytopathic effect and the mean number of uptaken erythrocytes, but not with percentage of phagocytic amoebae, showing that great variability can be observed in the same assay, according to the variable chosen. It was not possible to correlate isoenzyme and restriction fragment pattern with virulence indexes since all studied strains presented pathogenic patterns. The discordant results observed in different virulence assays suggests that virulence itself may not the directly assessed. What is in fact assessed are different biological characteristics or functions of the parasite more than virulence itself. These characteristics or functions may be related or not with pathogenic mechanisms occurring in the development of invasive amoebic diseaseParâmetros de virulência na caracterização de Cepas de Entamoeba histolytica. A caracterização quanto a virulência das diferentes cepas de E. histolytica foi avaliada através de ensaios in vivo e in vitro. Discrepâncias nesta caracterização têm surgido quando se compara os diferentes ensaios. Avaliamos alguns parâmetros de virulência na caracterização de 5 cepas axênicas de E. histolytica. Estas cepas foram caracterizadas com relação à sua capacidade para induzir abscesso em fígado de hamster

  8. A Sequential Model of Host Cell Killing and Phagocytosis by Entamoeba histolytica

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    Adam Sateriale

    2011-01-01

    Full Text Available The protozoan parasite Entamoeba histolytica is responsible for invasive intestinal and extraintestinal amebiasis. The virulence of Entamoeba histolytica is strongly correlated with the parasite's capacity to effectively kill and phagocytose host cells. The process by which host cells are killed and phagocytosed follows a sequential model of adherence, cell killing, initiation of phagocytosis, and engulfment. This paper presents recent advances in the cytolytic and phagocytic processes of Entamoeba histolytica in context of the sequential model.

  9. A Sequential Model of Host Cell Killing and Phagocytosis by Entamoeba histolytica

    Science.gov (United States)

    Sateriale, Adam; Huston, Christopher D.

    2011-01-01

    The protozoan parasite Entamoeba histolytica is responsible for invasive intestinal and extraintestinal amebiasis. The virulence of Entamoeba histolytica is strongly correlated with the parasite's capacity to effectively kill and phagocytose host cells. The process by which host cells are killed and phagocytosed follows a sequential model of adherence, cell killing, initiation of phagocytosis, and engulfment. This paper presents recent advances in the cytolytic and phagocytic processes of Entamoeba histolytica in context of the sequential model. PMID:21331284

  10. Differential identification of Entamoeba spp. based on the analysis of 18S rRNA.

    Science.gov (United States)

    Santos, Helena Lúcia Carneiro; Bandea, Rebecca; Martins, Luci Ana Fernandes; de Macedo, Heloisa Werneck; Peralta, Regina Helena Saramago; Peralta, Jose Mauro; Ndubuisi, Mackevin I; da Silva, Alexandre J

    2010-03-01

    Entamoeba histolytica is known to cause intestinal and extra-intestinal disease while the other Entamoeba species are not considered to be pathogenic. However, all Entamoeba spp. should be reported when identified in clinical samples. Entamoeba polecki, Entamoeba coli, and Entamoeba hartmanii can be differentiated morphologically from E. histolytica, but some of their diagnostic morphologic features overlap. E. histolytica, Entamoeba dispar, and Entamoeba moshkovskii are morphologically identical but can be differentiated using molecular tools. We developed a polymerase chain reaction (PCR) procedure followed by DNA sequencing of specific regions of 18S rRNA gene to differentiate the Entamoeba spp. commonly found in human stools. This approach was used to analyze 45 samples from cases evaluated for the presence of Entamoeba spp. by microscopy and a real-time PCR method capable of differential detection of E. histolytica and E. dispar. Our results demonstrated an agreement of approximately 98% (45/44) between the real-time PCR for E. histolytica and E. dispar and the 18S rRNA analysis described here. Five previously negative samples by microscopy revealed the presence of E. dispar, E. hartmanii, or E. coli DNA. In addition, we were able to detect E. hartmanii in a stool sample that had been previously reported as negative for Entamoeba spp. by microscopy. Further microscopic evaluation of this sample revealed the presence of E. hartmanii cysts, which went undetected during the first microscopic evaluation. This PCR followed by DNA sequencing will be useful to refine the diagnostic detection of Entamoeba spp. in stool and other clinical specimens.

  11. Comparison of multiplex-PCR and antigen detection for differential diagnosis of Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Helena Lúcia Carneiro Santos

    Full Text Available Amebiasis is an infection caused by Entamoeba histolytica. However, differentiation between E. histolytica and Entamoeba dispar, which are morphologically identical species, is essential for treatment decision, precaution of the invasive disease and public health. The purpose of the present study was to evaluate a Multiplex -PCR for detection and differentiation of E. histolytica from E. dispar from fresh stool samples in comparison with the coproantigen commercial ELISA. Microscopic examination of stools using the Coprotest method, detection of stool antigen by enzyme-linked immunosorbent assay kit and a home made Multiplex-PCR, were used for the diagnosis of amoebiasis infection. Analysis of the 127 stools samples by microscopy examination demonstrated that only 27 (21% samples were positive for E. histolytica/E. dispar complex. Among these stool samples, 11 were positive by Multiplex-PCR, with nine presenting the diagnostic fragment characteristic of E. dispar (96 bp and two presenting diagnostic fragment of E. histolytica (132 bp. Among negative samples detected by microscopic examination, three positive samples for E. dispar and one positive for E. histolytica by Multiplex-PCR was observed. This denotes a low sensibility of microscopic examination when a single stool sample is analyzed. Assay for detection of E. histolytica antigen was concordant with multiplex-PCR in relation to E. histolytica. Statistical analysis comparing the sensibility tests was not done because of the low number of E. histolytica cases. The results demonstrate the importance of the specific techniques use for the differentiation between E. histolytica and E. dispar.

  12. Identification of Entamoeba histolytica and E. dispar infection in Maceió, Alagoas State, northeast Brazil.

    Science.gov (United States)

    Santos, Rafael V; Fontes, Gilberto; Duarte, Iasmin A C; Santos-Júnior, José A; Rocha, Eliana M M

    2016-10-31

    A cross-sectional study was carried out to assess the prevalence of E. histolytica and E. dispar by examining stool samples obtained from 1,003 students of public schools in Maceió, Alagoas, Brazil. All stool samples were processed using the spontaneous sedimentation technique and examined microscopically for the presence of Entamoeba species. In order to distinguish infections caused by E. histolytica, fecal samples presenting cysts of Entamoeba were subjected to specific enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). The analysis of the fecal specimens by microscopy identified 6.4% (64/1,003) students positive for E. histolytica/E. dispar/E. moshkovskii cysts. The prevalence of E. histolytica detected by ELISA was 3.0% (30/1,003) and by PCR 2.8% (28/1,003), but the difference is not statistically significant (p > 0.05). The prevalence of E. dispar in schoolchildren was 5.0% (50/1,003). Mixed infections with E. histolytica and E. dispar were also detected by PCR.  Even though immunological and molecular methods have shown similar results for identification of E. histolytica, ELISA is advantageous over the PCR since it is relatively cheaper and easier to perform. Our study demonstrated the occurrence of E. histolytica in Maceió and highlights the need to introduce a specific diagnostic test to detect amoebiasis cases in public laboratories.

  13. The oxygen reduction pathway and heat shock stress response are both required for Entamoeba histolytica pathogenicity.

    Science.gov (United States)

    Olivos-García, Alfonso; Saavedra, Emma; Nequiz, Mario; Santos, Fabiola; Luis-García, Erika Rubí; Gudiño, Marco; Pérez-Tamayo, Ruy

    2016-05-01

    Several species belonging to the genus Entamoeba can colonize the mouth or the human gut; however, only Entamoeba histolytica is pathogenic to the host, causing the disease amoebiasis. This illness is responsible for one hundred thousand human deaths per year worldwide, affecting mainly underdeveloped countries. Throughout its entire life cycle and invasion of human tissues, the parasite is constantly subjected to stress conditions. Under in vitro culture, this microaerophilic parasite can tolerate up to 5 % oxygen concentrations; however, during tissue invasion the parasite has to cope with the higher oxygen content found in well-perfused tissues (4-14 %) and with reactive oxygen and nitrogen species derived from both host and parasite. In this work, the role of the amoebic oxygen reduction pathway (ORP) and heat shock response (HSP) are analyzed in relation to E. histolytica pathogenicity. The data suggest that in contrast with non-pathogenic E. dispar, the higher level of ORP and HSPs displayed by E. histolytica enables its survival in tissues by diminishing and detoxifying intracellular oxidants and repairing damaged proteins to allow metabolic fluxes, replication and immune evasion.

  14. Actin, RhoA, and Rab11 participation during encystment in Entamoeba invadens.

    Science.gov (United States)

    Herrera-Martínez, M; Hernández-Ramírez, V I; Lagunes-Guillén, A E; Chávez-Munguía, B; Talamás-Rohana, P

    2013-01-01

    In the genus Entamoeba, actin reorganization is necessary for cyst differentiation; however, its role is still unknown. The aim of this work was to investigate the role of actin and encystation-related proteins during Entamoeba invadens encystation. Studied proteins were actin, RhoA, a small GTPase involved through its effectors in the rearrangement of the actin cytoskeleton; Rab11, a protein involved in the transport of encystation vesicles; and enolase, as an encystment vesicles marker. Results showed a high level of polymerized actin accompanied by increased levels of RhoA-GTP during cell rounding and loss of vacuoles. Cytochalasin D, an actin polymerization inhibitor, and Y27632, an inhibitor of RhoA activity, reduced encystment in 80%. These inhibitors also blocked cell rounding, disposal of vacuoles, and the proper formation of the cysts wall. At later times, F-actin and Rab11 colocalized with enolase, suggesting that Rab11 could participate in the transport of the cyst wall components through the F-actin cytoskeleton. These results suggest that actin cytoskeleton rearrangement is playing a decisive role in determining cell morphology changes and helping with the transport of cell wall components to the cell surface during encystment of E. invadens.

  15. Entamoeba Encystation: New Targets to Prevent the Transmission of Amebiasis

    Science.gov (United States)

    Mi-ichi, Fumika; Yoshida, Hiroki; Hamano, Shinjiro

    2016-01-01

    Amebiasis is caused by Entamoeba histolytica infection and can produce a broad range of clinical signs, from asymptomatic cases to patients with obvious symptoms. The current epidemiological and clinical statuses of amebiasis make it a serious public health problem worldwide. The Entamoeba life cycle consists of the trophozoite, the causative agent for amebiasis, and the cyst, the form responsible for transmission. These two stages are connected by “encystation” and “excystation.” Hence, developing novel strategies to control encystation and excystation will potentially lead to new measures to block the transmission of amebiasis by interrupting the life cycle of the causative agent. Here, we highlight studies investigating encystation using inhibitory chemicals and categorize them based on the molecules inhibited. We also present a perspective on new strategies to prevent the transmission of amebiasis. PMID:27764256

  16. Entamoeba Encystation: New Targets to Prevent the Transmission of Amebiasis.

    Science.gov (United States)

    Mi-Ichi, Fumika; Yoshida, Hiroki; Hamano, Shinjiro

    2016-10-01

    Amebiasis is caused by Entamoeba histolytica infection and can produce a broad range of clinical signs, from asymptomatic cases to patients with obvious symptoms. The current epidemiological and clinical statuses of amebiasis make it a serious public health problem worldwide. The Entamoeba life cycle consists of the trophozoite, the causative agent for amebiasis, and the cyst, the form responsible for transmission. These two stages are connected by "encystation" and "excystation." Hence, developing novel strategies to control encystation and excystation will potentially lead to new measures to block the transmission of amebiasis by interrupting the life cycle of the causative agent. Here, we highlight studies investigating encystation using inhibitory chemicals and categorize them based on the molecules inhibited. We also present a perspective on new strategies to prevent the transmission of amebiasis.

  17. Entamoeba Encystation: New Targets to Prevent the Transmission of Amebiasis.

    Directory of Open Access Journals (Sweden)

    Fumika Mi-Ichi

    2016-10-01

    Full Text Available Amebiasis is caused by Entamoeba histolytica infection and can produce a broad range of clinical signs, from asymptomatic cases to patients with obvious symptoms. The current epidemiological and clinical statuses of amebiasis make it a serious public health problem worldwide. The Entamoeba life cycle consists of the trophozoite, the causative agent for amebiasis, and the cyst, the form responsible for transmission. These two stages are connected by "encystation" and "excystation." Hence, developing novel strategies to control encystation and excystation will potentially lead to new measures to block the transmission of amebiasis by interrupting the life cycle of the causative agent. Here, we highlight studies investigating encystation using inhibitory chemicals and categorize them based on the molecules inhibited. We also present a perspective on new strategies to prevent the transmission of amebiasis.

  18. Entamoeba dispar strains: analysis of polymorphism in Tunisian isolates.

    Science.gov (United States)

    Ayed, Soumaya Ben; Bouratbine, Aida

    2013-01-01

    The ability to detect intra-species polymorphism in Entamoeba histolytica and Entamoeba dispar is an important tool for studying geographic distribution and transmission mechanisms. E. dispar and E. histolytica share the same mechanism for transmission among human hosts, and so after differentiation between these species. We studied the intra-species variation and distribution of E. dispar strains obtained from cyst passers, specifically from African students and Tunisian food handlers. We analyzed the polymorphic region of the chitinase protein gene in 13 individuals infected with E. dispar, of which 9 were from Tunisia and 4 from other African countries. We identified 7 different chitinase patterns in Tunisians while the 4 isolates from other countries each had a distinct pattern. Two of the patterns we found have been reported in studies from Mexico and India, possibly indicating worldwide spread of certain strains.

  19. Genetic architecture of open angle glaucoma and related determinants

    NARCIS (Netherlands)

    Ramdas, W.D.; Amin, N.; van Koolwijk, L.M.E.; Janssens, A.C.J.W.; Demirkan, A.; de Jong, P.T.V.M.; Aulchenko, Y.S.; Wolfs, R.C.W.; Hofman, A.; Rivadeneira, F.; Uitterlinden, A.G.; Oostra, B.A.; Lemij, H.G.; Klaver, C.C.W.; Vingerling, J.R.; Jansonius, N.M.; van Duijn, C.M.

    2011-01-01

    Background Although the vertical cup-disc ratio (VCDR) and intraocular pressure (IOP) are important determinants of open angle glaucoma (OAG), it is unclear to what extent the genetic origin of these traits overlap with those of OAG. We evaluated whether the same genes that determine VCDR and IOP al

  20. Prevalence of Entamoeba histolytica, Giardia lamblia, and ...

    African Journals Online (AJOL)

    2016-06-29

    Jun 29, 2016 ... Egyptian food handlers but not among the Libyan food handlers. .... Reassessment of the epidemiology of amebiasis: state of the art. Infect Genet Evol. ... Cambridge, United Kingdom: The Royal Society of Chemistry;. 2008. p.

  1. Altered lipid parameters in patients infected with Entamoeba histolytica, Entamoeba dispar and Giardia lamblia.

    Science.gov (United States)

    Bansal, D; Bhatti, H S; Sehgal, R

    2005-01-01

    Information on the effect of parasitic infections on lipid parameters is scarce. Certain parasites induce significant changes in lipid parameters, as demonstrated by the fact that substitution of lipid/cholesterol for serum in axenic culture medium (in vitro) and in experimental models (in vivo) supports vigorous growth of Entamoeba histolytica. Thus, significant changes in lipid parameters may be induced in an infected host. Blood samples are obtained from intestinal amoebiasis patients passing E. histolytica (n=8), E. dispar (n=15) or Giardia lamblia (n=9) cysts, or diagnosed with amoebic liver abscess (ALA; n=50) and from apparently normal healthy individuals (control group; n=30). Levels of total serum cholesterol, high-density lipoprotein and low-density lipoprotein are assessed using commercial kits. E. histolytica and E. dispar isolates are differentiated by hexokinase isoenzyme electrophoresis and by enzyme-linked immunosorbent assay (ELISA; Techlab) tests. Results show that E. histolytica, E. dispar and G. lamblia cyst passers had significantly lower levels of total serum cholesterol (73.42 +/- 2.24 mg/dL), compared to levels in ALA cases (101 +/- 2.85 mg/dL) and in controls (166.26 +/- 2.02 mg/dL). Further study of a greater number of cases is needed to explore the relevance of this finding.

  2. Immune Evasion Mechanisms of Entamoeba histolytica: Progression to Disease

    OpenAIRE

    2015-01-01

    Entamoeba histolytica (Eh) is a protozoan parasite that infects 10% of the world's population and results in 100,000 deaths/year from amebic dysentery and/or liver abscess. In most cases, this extracellular parasite colonizes the colon by high affinity binding to MUC2 mucin without disease symptoms, whereas in some cases, Eh triggers an aggressive inflammatory response upon invasion of the colonic mucosa. The specific host-parasite factors critical for disease pathogenesis are still not well ...

  3. Immune evasion mechanisms of Entamoeba histolytica: progression to disease

    OpenAIRE

    2015-01-01

    Entamoeba histolytica (Eh) is a protozoan parasite that infects 10% of the world’s population and results in 100,000 deaths/year from amebic dysentery and/or liver abscess. In most cases, this extracellular parasite colonizes the colon by high affinity binding to MUC2 mucin without disease symptoms, whereas in some cases, Eh triggers an aggressive inflammatory response upon invasion of the colonic mucosa. The specific host-parasite factors critical for disease pathogenesis are still not well ...

  4. First molecular identification of Entamoeba moshkovskii in Malaysia.

    Science.gov (United States)

    Anuar, Tengku Shahrul; Al-Mekhlafi, Hesham M; Ghani, Mohamed Kamel Abdul; Azreen, Siti Nor; Salleh, Fatmah Md; Ghazali, Nuraffini; Bernadus, Mekadina; Moktar, Norhayati

    2012-10-01

    Entamoeba moshkovskii and Entamoeba dispar are microscopically indistinguishable from the pathogenic species Entamoeba histolytica. Although sporadic cases of human infection with E. moshkovskii have been reported, the amoeba is still considered primarily as a free-living amoeba. A cross-sectional study was carried out among Orang Asli communities in 3 different states of Peninsular Malaysia. Fecal samples were examined by formalin-ether sedimentation and trichrome staining techniques and then single-round PCR assay was used to detect E. moshkovskii. Out of 500 fecal samples examined microscopically, 93 (18·6%) samples were positive for E. histolytica/E. dispar/E. moshkovskii complex cysts and/or trophozoites. PCR products were detected in 106 fecal samples. E. moshkovskii isolates were detected in 13 (12·3%) fecal samples. Of the 13 E. moshkovskii-positive samples, 5 were of single isolation of E. moshkovskii, 6 were also positive for E. dispar, and only 2 samples were positive for E. dispar and E. histolytica. Moreover, 3 E. moshkovskii-positive samples were collected from symptomatic individuals while the remaining 10 samples were from asymptomatic subjects. This is the first report on the identification of E. moshkovskii in Malaysia. Further studies are needed to confirm the pathogenicity of E. moshkovskii infection and determine the epidemiology among Orang Asli communities in Malaysia.

  5. Search for Genetic Variants Underlying Musical Aptitude and Related Traits

    OpenAIRE

    Ukkola-Vuoti, Liisa

    2013-01-01

    Music perception and practice represents complex cognitive functions of the brain. There is an abundance of data about the neurophysiological effects of music on the human brain, but heritability and especially molecular studies have been lacking. The development of genome technologies and bioinformatics has enabled the identification of genetic variants underlying complex human traits. These methods can be applied to normal human traits like music perception and performance. Prior to th...

  6. Genetics

    Science.gov (United States)

    ... Inheritance; Heterozygous; Inheritance patterns; Heredity and disease; Heritable; Genetic markers ... The chromosomes are made up of strands of genetic information called DNA. Each chromosome contains sections of ...

  7. Genetics Home Reference: CASK-related intellectual disability

    Science.gov (United States)

    ... Conditions CASK-related intellectual disability CASK-related intellectual disability Printable PDF Open All Close All Enable Javascript ... the expand/collapse boxes. Description CASK -related intellectual disability is a disorder of brain development that has ...

  8. Genetics Home Reference: SYNGAP1-related intellectual disability

    Science.gov (United States)

    ... Conditions SYNGAP1-related intellectual disability SYNGAP1-related intellectual disability Printable PDF Open All Close All Enable Javascript ... the expand/collapse boxes. Description SYNGAP1 -related intellectual disability is a neurological disorder characterized by moderate to ...

  9. Genetics Home Reference: CATSPER1-related nonsyndromic male infertility

    Science.gov (United States)

    ... related nonsyndromic male infertility CATSPER1-related nonsyndromic male infertility Enable Javascript to view the expand/collapse boxes. ... All Close All Description CATSPER1 -related nonsyndromic male infertility is a condition that affects the function of ...

  10. Genetics Home Reference: myostatin-related muscle hypertrophy

    Science.gov (United States)

    ... Health Conditions myostatin-related muscle hypertrophy myostatin-related muscle hypertrophy Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body ...

  11. Identification of calcium-transporting ATPases of Entamoeba histolytica and cellular localization of the putative SERCA.

    Science.gov (United States)

    Martinez-Higuera, Aarón; Salas-Casas, Andrés; Calixto-Gálvez, Mercedes; Chávez-Munguía, Bibiana; Pérez-Ishiwara, D Guillermo; Ximénez, Cecilia; Rodríguez, Mario A

    2013-09-01

    Calcium has an important role on signaling of different cellular processes in the protozoa parasite Entamoeba histolytica, including development and pathogenesis. However, the systems that control calcium responses in this parasite are incompletely understood. Calcium-ATPases (Ca(2+)-ATPases) are proteins that play an important role in calcium homeostasis by catalyzing the active efflux of this ion from cytoplasm and are essential to the correct functioning of the cell machinery. Here, we reported the identification of five E. histolytica genes encoding putative Ca(2+)-ATPases, three related to PMCA, and two related to organellar ATPases. RT-PCR assays showed that all those genes are expressed in trophozoites and specific antibodies against the SERCA-like member located this protein in a continuous cytoplasmic network, supporting the hypothesis that it corresponds to the Ca(2+)-ATPase responsible to sequester calcium in the endoplasmic reticulum of this parasite.

  12. Differentiation of Entamoeba histolytica and Entamoeba dispar in cyst-passers by immunoblot.

    Science.gov (United States)

    Lee, M; Hong, S T

    1996-12-01

    Differentiation of invasive strains of Entamoeba histolytica according to their pathogenicity has been a topic of long debate, but now the pathogenic species only is regarded as E. histolytica while the non pathogenic species is E. dispar. The present study applied immunoblot to differentiate infections of the two species among microscopically-detected cyst-passers in Korea. The crude extract of E. histolytica separated in 5.20% gradient gels, revealed many fractions of 94, 81, 71, 50, 44, 38.5, 37.5, 29, 19, and 18 kDa when the cysteine proteinase inhibitor, E64, was supplemented. The scrum IgG antibody of 3 proven E, histolytica cases reacted with the antigenic fractions of 117, 110, 99, 68, 66, 60, 54, 52, 46, and 45 kDa. Sera of PCR confirmed 3 cases of E. dispar reacted only to the 117 kDa fraction of the E. histolytica crude extract which was regarded as non-specific. To the antigen of monoxenic E. dispar, sera of E. dispar and E. histolytica cases showed the same immunoblot reactions. The serum IgA antibody reacted with several antigenic fractions of both E. histolytica and E. dispar, but IgM and IgE antibodies showed no reaction to either antigen. Sera of 24 symptomless amebic cyst passers were screened with the E. histolytica antigen; two were found to be infected by E. histolytica and 22 were by E. dispar. The present findings suggest that in Korea most of asymptomatic cyst passers of E. histolytica are carriers of E. dispar. Immunoblot using E. histolytica antigen is a good technique for the differentiation of E. histolytica and E. dispar infections.

  13. Asymmetry of genetic variation in fitness-related traits: apparent stabilizing selection on g(max).

    Science.gov (United States)

    McGuigan, Katrina; Blows, Mark W

    2009-11-01

    The maintenance of genetic variation in traits closely associated with fitness remains a key unresolved issue in evolutionary genetics. One important qualification on the observation of genetic variation in fitness-related traits is that such traits respond asymmetrically to selection, evolving to a greater extent in the direction of lower fitness. Here we test the hypothesis that standing genetic variation in fitness-related traits is principally maintained for unfit phenotypes. Male Drosophila bunnanda vary in mating success (the primary determinant of male fitness) due to female mate choice. We used competitive mating success to partitioning males into two groups: successful (high fitness) and unsuccessful (low fitness). Relative to successful males, unsuccessful males harbored considerably greater levels of additive genetic variation for sexual signaling traits. This genetic asymmetry was detected for a multivariate trait that we demonstrated was not directly under stabilizing sexual selection, leading us to conclude the trait was under apparent stabilizing selection. Consequently, our results suggest genetic variance might be biased toward low fitness even for traits that are not themselves the direct targets of selection. Simple metrics of genetic variance are unlikely to be adequate descriptors of the complex nature of the genetic basis of traits under selection.

  14. Detection and molecular characterisation of Giardia duodenalis, Cryptosporidium spp. and Entamoeba spp. among patients with gastrointestinal symptoms in Gambo Hospital, Oromia Region, southern Ethiopia.

    Science.gov (United States)

    Flecha, María J; Benavides, Cynthia M; Tissiano, Gabriel; Tesfamariam, Abraham; Cuadros, Juan; de Lucio, Aida; Bailo, Begoña; Cano, Lourdes; Fuentes, Isabel; Carmena, David

    2015-09-01

    To assess the prevalence and genetic diversity of the enteric protozoa species G. duodenalis, Cryptosporidium spp. and Entamoeba histolytica in individuals with gastrointestinal symptoms compatible with infections by these pathogens seeking medical attention in a rural area in southern Ethiopia. A total of 92 stool samples were initially screened by direct microscopy and immunochromatography and further confirmed by molecular methods. G. duodenalis-positive samples were molecularly characterised by multilocus genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. PCR and DNA sequence analysis of the gene encoding the 60-kDa glycoprotein was used for the subtyping of Cryptosporidium isolates. Detection and differential diagnosis of E. histolytica/dispar were conducted by real-time PCR. PCR-based prevalences were 10.9% for G. duodenalis, 1.1% for Cryptosporidium spp. and 3.3% for Entamoeba spp. Seven (four novel and three known) subtypes of G. duodenalis assemblage B were identified at the GDH locus and 5 (one novel and four known) at the BG locus. A novel variant of C. hominis subtype IbA9G3 was also identified. Two Entamoeba isolates were assigned to E. dispar and an additional one to E. histolytica. Although preliminary, our results strongly suggest that giardiasis, cryptosporidiosis and amoebiasis represent a significant burden in Ethiopian rural population. © 2015 John Wiley & Sons Ltd.

  15. Genetic and Environmental Etiologies of the Longitudinal Relations between Pre-reading Skills and Reading

    Science.gov (United States)

    Christopher, Micaela E.; Hulslander, Jacqueline; Byrne, Brian; Samuelsson, Stefan; Keenan, Janice M.; Pennington, Bruce; DeFries, John C.; Wadsworth, Sally J.; Willcutt, Erik; Olson, Richard K.

    2014-01-01

    The present study explored the environmental and genetic etiologies of the longitudinal relations between pre-reading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post-1st grade (M = 7.4 years), and post-4th grade (M = 10.4 years). Genetic influences on five pre-reading skills (print knowledge, rapid naming, phonological awareness, vocabulary, and verbal memory) were primarily responsible for relations with word reading and spelling. However, relations with post-4th-grade reading comprehension were due both to genetic and shared environmental influences. Genetic and shared environmental influences that were common among the pre-reading variables covaried with reading and spelling, as did genetic influences unique to verbal memory (only post-4th-grade comprehension), print knowledge, and rapid naming. PMID:25263167

  16. Genetic and environmental etiologies of the longitudinal relations between prereading skills and reading.

    Science.gov (United States)

    Christopher, Micaela E; Hulslander, Jacqueline; Byrne, Brian; Samuelsson, Stefan; Keenan, Janice M; Pennington, Bruce; DeFries, John C; Wadsworth, Sally J; Willcutt, Erik; Olson, Richard K

    2015-01-01

    The present study explored the environmental and genetic etiologies of the longitudinal relations between prereading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post-first grade (M = 7.4 years), and post-fourth grade (M = 10.4 years). Genetic influences on five prereading skills (print knowledge, rapid naming, phonological awareness, vocabulary, and verbal memory) were primarily responsible for relations with word reading and spelling. However, relations with post-fourth-grade reading comprehension were due to both genetic and shared environmental influences. Genetic and shared environmental influences that were common among the prereading variables covaried with reading and spelling, as did genetic influences unique to verbal memory (only post-fourth-grade comprehension), print knowledge, and rapid naming. © 2014 The Authors. Child Development © 2014 Society for Research in Child Development, Inc.

  17. Genetics Home Reference: CHMP2B-related frontotemporal dementia

    Science.gov (United States)

    ... Conditions CHMP2B-related frontotemporal dementia CHMP2B-related frontotemporal dementia Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description CHMP2B -related frontotemporal dementia is a progressive brain disorder that affects personality, ...

  18. Media violence and children’s ADHD-related behaviors: a genetic susceptibility perspective

    NARCIS (Netherlands)

    Nikkelen, S.W.C.; Vossen, H.G.M.; Valkenburg, P.M.; Velders, F.P.; Windhorst, D.A.; Jaddoe, V.W.V.; Hofman, A.; Verhulst, F.C.; Tiemeier, H.

    2014-01-01

    This study examined the relationship between media violence exposure and Attention-deficit/hyperactivity disorder (ADHD)-related behaviors. Using survey (parent-reported) and genetic data of 1,612 Dutch children (aged 5 to 9 years), we examined genetic disposition as a possible cause of individual

  19. Children's History of Speech-Language Difficulties: Genetic Influences and Associations with Reading-Related Measures

    Science.gov (United States)

    DeThorne, Laura Segebart; Hart, Sara A.; Petrill, Stephen A.; Deater-Deckard, Kirby; Thompson, Lee Anne; Schatschneider, Chris; Davison, Megan Dunn

    2006-01-01

    Purpose: This study examined (a) the extent of genetic and environmental influences on children's articulation and language difficulties and (b) the phenotypic associations between such difficulties and direct assessments of reading-related skills during early school-age years. Method: Behavioral genetic analyses focused on parent-report data…

  20. Media violence and children’s ADHD-related behaviors: a genetic susceptibility perspective

    NARCIS (Netherlands)

    Nikkelen, S.W.C.; Vossen, H.G.M.; Valkenburg, P.M.; Velders, F.P.; Windhorst, D.A.; Jaddoe, V.W.V.; Hofman, A.; Verhulst, F.C.; Tiemeier, H.

    2014-01-01

    This study examined the relationship between media violence exposure and Attention-deficit/hyperactivity disorder (ADHD)-related behaviors. Using survey (parent-reported) and genetic data of 1,612 Dutch children (aged 5 to 9 years), we examined genetic disposition as a possible cause of individual d

  1. The Genetics of Stress-Related Disorders: PTSD, Depression, and Anxiety Disorders.

    Science.gov (United States)

    Smoller, Jordan W

    2016-01-01

    Research into the causes of psychopathology has largely focused on two broad etiologic factors: genetic vulnerability and environmental stressors. An important role for familial/heritable factors in the etiology of a broad range of psychiatric disorders was established well before the modern era of genomic research. This review focuses on the genetic basis of three disorder categories-posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and the anxiety disorders-for which environmental stressors and stress responses are understood to be central to pathogenesis. Each of these disorders aggregates in families and is moderately heritable. More recently, molecular genetic approaches, including genome-wide studies of genetic variation, have been applied to identify specific risk variants. In this review, I summarize evidence for genetic contributions to PTSD, MDD, and the anxiety disorders including genetic epidemiology, the role of common genetic variation, the role of rare and structural variation, and the role of gene-environment interaction. Available data suggest that stress-related disorders are highly complex and polygenic and, despite substantial progress in other areas of psychiatric genetics, few risk loci have been identified for these disorders. Progress in this area will likely require analysis of much larger sample sizes than have been reported to date. The phenotypic complexity and genetic overlap among these disorders present further challenges. The review concludes with a discussion of prospects for clinical translation of genetic findings and future directions for research.

  2. Histopathological and immunohistochemical study of the hepatic lesions experimentally induced by Entamoeba dispar

    Directory of Open Access Journals (Sweden)

    C. A. X. Costa

    2010-08-01

    Full Text Available The sequence of hepatic necrotic-inflammatory events produced by Entamoeba dispar are originally described in this work. For the first time were described in details the experimental lesions produced by E. dispar, as well as the distribution of the trophozoites detected by the immunohistochemistry. Animals experimentally infected with E. dispar presented necrosis, thrombosis and chronic granulomatous inflammation. Immunoreactive products derived from trofozoites were observed close or associated with trophozoites, epithelioid cells, leucocytes and hepatocytes. Few are the articles on the literature about virulence of E. dispar, which is approximately 9 times more frequent than to E. histolytica. Variation in the virulence is, therefore expected and signalizing the need of the continuity of studies with E. dispar strains from different places in the world. Taking into account that E. dispar is a closely related species to E. histolytica, these studies could determine new elements involved with E. histolytica pathogenesis, helping us to understand better the disease.

  3. Genetics Home Reference: age-related macular degeneration

    Science.gov (United States)

    ... Resources (3 links) BrightFocus Foundation: Macular Degeneration Treatment Macular Degeneration Partnership: Low Vision Rehabilitation Prevent Blindness America: Age-Related Macular Degeneration (AMD) ...

  4. Genetics Home Reference: FOXP2-related speech and language disorder

    Science.gov (United States)

    ... FOXP2-related speech and language disorder FOXP2-related speech and language disorder Printable PDF Open All Close All Enable Javascript ... Information & Resources MedlinePlus (3 links) Encyclopedia: Apraxia Encyclopedia: Speech Disorders - Children Health Topic: Speech and Language Problems in ...

  5. Interest in genetic testing in Ashkenazi Jewish Parkinson's disease patients and their unaffected relatives.

    Science.gov (United States)

    Gupte, Manisha; Alcalay, Roy N; Mejia-Santana, Helen; Raymond, Deborah; Saunders-Pullman, Rachel; Roos, Ernest; Orbe-Reily, Martha; Tang, Ming-X; Mirelman, Anat; Ozelius, Laurie; Orr-Urtreger, Avi; Clark, Lorraine; Giladi, Nir; Bressman, Susan; Marder, Karen

    2015-04-01

    Our objective was to explore interest in genetic testing among Ashkenazi Jewish (AJ) Parkinson's Disease (PD) cases and first-degree relatives, as genetic testing for LRRK2 G2019S is widely available. Approximately 18 % of AJ PD cases carry G2019S mutations; penetrance estimations vary between 24 and 100 % by age 80. A Genetic Attitude Questionnaire (GAQ) was administered at two New York sites to PD families unaware of LRRK2 G2019S mutation status. The association of G2019S, age, education, gender and family history of PD with desire for genetic testing (outcome) was modeled using logistic regression. One-hundred eleven PD cases and 77 relatives completed the GAQ. Both PD cases and relatives had excellent PD-specific genetic knowledge. Among PD, 32.6 % "definitely" and 41.1 % "probably" wanted testing, if offered "now." Among relatives, 23.6 % "definitely" and 36.1 % "probably" wanted testing "now." Desire for testing in relatives increased incrementally based on hypothetical risk of PD. The most important reasons for testing in probands and relatives were: if it influenced medication response, identifying no mutation, and early prevention and treatment. In logistic regression, older age was associated with less desire for testing in probands OR = 0.921 95%CI 0.868-0.977, p = 0.009. Both probands and relatives express interest in genetic testing, despite no link to current treatment or prevention.

  6. Eukaryotic checkpoints are absent in the cell division cycle of Entamoeba histolytica

    Indian Academy of Sciences (India)

    Sulagna Banerjee; Suchismita Das; Anuradha Lohia

    2002-11-01

    Fidelity in transmission of genetic characters is ensured by the faithful duplication of the genome, followed by equal segregation of the genetic material in the progeny. Thus, alternation of DNA duplication (S-phase) and chromosome segregation during the M-phase are hallmarks of most well studied eukaryotes. Several rounds of genome reduplication before chromosome segregation upsets this cycle and leads to polyploidy. Polyploidy is often witnessed in cells prior to differentiation, in embryonic cells or in diseases such as cancer. Studies on the protozoan parasite, Entamoeba histolytica suggest that in its proliferative phase, this organism may accumulate polyploid cells. It has also been shown that although this organism contains sequence homologs of genes which are known to control the cell cycle of most eukaryotes, these genes may be structurally altered and their equivalent function yet to be demonstrated in amoeba. The available information suggests that surveillance mechanisms or ‘checkpoints’ which are known to regulate the eukaryotic cell cycle may be absent or altered in E. histolytica.

  7. Sensing DNA methylation in the protozoan parasite Entamoeba histolytica.

    Science.gov (United States)

    Lavi, Tal; Isakov, Elada; Harony, Hala; Fisher, Ohad; Siman-Tov, Rama; Ankri, Serge

    2006-12-01

    In the protozoan parasite Entamoeba histolytica, 5-methylcytosine (m5C) was found predominantly in repetitive elements. Its formation is catalysed by Ehmeth, a DNA methyltransferase that belongs to the Dnmt2 subfamily. Here we describe a 32 kDa nuclear protein that binds in vitro with higher affinity to the methylated form of a DNA encoding a reverse transcriptase of an autonomous non-long-terminal repeat retrotransposon (RT LINE) compared with the non-methylated RT LINE. This protein, named E. histolytica-methylated LINE binding protein (EhMLBP), was purified from E. histolytica nuclear lysate, identified by mass spectrometry, and its corresponding gene was cloned. EhMLBP corresponds to a gene of unknown function that shares strong homology with putative proteins present in Entamoeba dispar and Entamoeba invadens. In contrast, the homology dropped dramatically when non-Entamoebidae sequences were considered and only a weak sequence identity was found with Trypanosoma and several prokaryotic histone H1. Recombinant EhMLBP showed the same binding preference for methylated RT LINE as the endogenous EhMLBP. Deletion mapping analysis localized the DNA binding region at the C-terminal part of the protein. This region is sufficient to assure the binding to methylated RT LINE with high affinity. Western blot and immunofluorescence microscopy, using an antibody raised against EhMLBP, showed that it has a nuclear localization. Chromatin immunoprecipitation (ChIP) confirmed that EhMLBP interacts with RT LINE in vivo. Finally, we showed that EhMLBP can also bind rDNA episome, a DNA that is methylated in the parasite. This suggests that EhMLBP may serve as a sensor of methylated repetitive DNA. This is the first report of a DNA-methylated binding activity in protozoa.

  8. Comparative Landscape Genetics of Three Closely Related Sympatric Hesperid Butterflies with Diverging Ecological Traits

    Science.gov (United States)

    Engler, Jan O.; Balkenhol, Niko; Filz, Katharina J.; Habel, Jan C.; Rödder, Dennis

    2014-01-01

    To understand how landscape characteristics affect gene flow in species with diverging ecological traits, it is important to analyze taxonomically related sympatric species in the same landscape using identical methods. Here, we present such a comparative landscape genetic study involving three closely related Hesperid butterflies of the genus Thymelicus that represent a gradient of diverging ecological traits. We analyzed landscape effects on their gene flow by deriving inter-population connectivity estimates based on different species distribution models (SDMs), which were calculated from multiple landscape parameters. We then used SDM output maps to calculate circuit-theoretic connectivity estimates and statistically compared these estimates to actual genetic differentiation in each species. We based our inferences on two different analytical methods and two metrics of genetic differentiation. Results indicate that land use patterns influence population connectivity in the least mobile specialist T. acteon. In contrast, populations of the highly mobile generalist T. lineola were panmictic, lacking any landscape related effect on genetic differentiation. In the species with ecological traits in between those of the congeners, T. sylvestris, climate has a strong impact on inter-population connectivity. However, the relative importance of different landscape factors for connectivity varies when using different metrics of genetic differentiation in this species. Our results show that closely related species representing a gradient of ecological traits also show genetic structures and landscape genetic relationships that gradually change from a geographical macro- to micro-scale. Thus, the type and magnitude of landscape effects on gene flow can differ strongly even among closely related species inhabiting the same landscape, and depend on their relative degree of specialization. In addition, the use of different genetic differentiation metrics makes it possible to

  9. Genetics Home Reference: REN-related kidney disease

    Science.gov (United States)

    ... Testing Registry: Hyperuricemic nephropathy, familial juvenile, 2 Other Diagnosis and Management Resources (3 links) GeneReview: Autosomal Dominant Tubulointerstitial Kidney Disease, REN-Related MedlinePlus Encyclopedia: Hyperkalemia MedlinePlus Encyclopedia: Renin ...

  10. SNAP-tag technology optimized for use in Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    Adam Sateriale

    Full Text Available Entamoeba histolytica is a protozoan parasite responsible for invasive intestinal and extraintestinal amebiasis. The pathology of amebiasis is still poorly understood, which can be largely attributed to lack of molecular tools. Here we present the optimization of SNAP-tag technology via codon optimization specific for E. histolytica. The resultant SNAP protein is highly expressed in amebic trophozoites, and shows proper localization when tagged with an endoplasmic reticulum retention signal. We further demonstrate the capabilities of this system using super resolution microscopy, done for the first time in E. histolytica.

  11. Genetic diversity is related to climatic variation and vulnerability in threatened bull trout

    Science.gov (United States)

    Kovach, Ryan; Muhlfeld, Clint C.; Wade, Alisa A.; Hand, Brian K.; Whited, Diane C.; DeHaan, Patrick W.; Al-Chokhachy, Robert K.; Luikart, Gordon

    2015-01-01

    Understanding how climatic variation influences ecological and evolutionary processes is crucial for informed conservation decision-making. Nevertheless, few studies have measured how climatic variation influences genetic diversity within populations or how genetic diversity is distributed across space relative to future climatic stress. Here, we tested whether patterns of genetic diversity (allelic richness) were related to climatic variation and habitat features in 130 bull trout (Salvelinus confluentus) populations from 24 watersheds (i.e., ~4–7th order river subbasins) across the Columbia River Basin, USA. We then determined whether bull trout genetic diversity was related to climate vulnerability at the watershed scale, which we quantified on the basis of exposure to future climatic conditions (projected scenarios for the 2040s) and existing habitat complexity. We found a strong gradient in genetic diversity in bull trout populations across the Columbia River Basin, where populations located in the most upstream headwater areas had the greatest genetic diversity. After accounting for spatial patterns with linear mixed models, allelic richness in bull trout populations was positively related to habitat patch size and complexity, and negatively related to maximum summer temperature and the frequency of winter flooding. These relationships strongly suggest that climatic variation influences evolutionary processes in this threatened species and that genetic diversity will likely decrease due to future climate change. Vulnerability at a watershed scale was negatively correlated with average genetic diversity (r = −0.77;P bull trout and other imperiled species. Genetic diversity is already depressed where climatic vulnerability is highest; it will likely erode further in the very places where diversity may be most needed for future persistence.

  12. The molecular genetics of Marfan syndrome and related disorders

    Science.gov (United States)

    Robinson, P N; Arteaga‐Solis, E; Baldock, C; Collod‐Béroud, G; Booms, P; De Paepe, A; Dietz, H C; Guo, G; Handford, P A; Judge, D P; Kielty, C M; Loeys, B; Milewicz, D M; Ney, A; Ramirez, F; Reinhardt, D P; Tiedemann, K; Whiteman, P; Godfrey, M

    2006-01-01

    Marfan syndrome (MFS), a relatively common autosomal dominant hereditary disorder of connective tissue with prominent manifestations in the skeletal, ocular, and cardiovascular systems, is caused by mutations in the gene for fibrillin‐1 (FBN1). The leading cause of premature death in untreated individuals with MFS is acute aortic dissection, which often follows a period of progressive dilatation of the ascending aorta. Recent research on the molecular physiology of fibrillin and the pathophysiology of MFS and related disorders has changed our understanding of this disorder by demonstrating changes in growth factor signalling and in matrix‐cell interactions. The purpose of this review is to provide a comprehensive overview of recent advances in the molecular biology of fibrillin and fibrillin‐rich microfibrils. Mutations in FBN1 and other genes found in MFS and related disorders will be discussed, and novel concepts concerning the complex and multiple mechanisms of the pathogenesis of MFS will be explained. PMID:16571647

  13. Genetic mechanisms and age-related macular degeneration: common variants, rare variants, copy number variations, epigenetics, and mitochondrial genetics

    Directory of Open Access Journals (Sweden)

    Liu Melissa M

    2012-08-01

    Full Text Available Abstract Age-related macular degeneration (AMD is a complex and multifaceted disease involving contributions from both genetic and environmental influences. Previous work exploring the genetic contributions of AMD has implicated numerous genomic regions and a variety of candidate genes as modulators of AMD susceptibility. Nevertheless, much of this work has revolved around single-nucleotide polymorphisms (SNPs, and it is apparent that a significant portion of the heritability of AMD cannot be explained through these mechanisms. In this review, we consider the role of common variants, rare variants, copy number variations, epigenetics, microRNAs, and mitochondrial genetics in AMD. Copy number variations in regulators of complement activation genes (CFHR1 and CFHR3 and glutathione S transferase genes (GSTM1 and GSTT1 have been associated with AMD, and several additional loci have been identified as regions of potential interest but require further evaluation. MicroRNA dysregulation has been linked to the retinal pigment epithelium degeneration in geographic atrophy, ocular neovascularization, and oxidative stress, all of which are hallmarks in the pathogenesis of AMD. Certain mitochondrial DNA haplogroups and SNPs in mitochondrially encoded NADH dehydrogenase genes have also been associated with AMD. The role of these additional mechanisms remains only partly understood, but the importance of their further investigation is clear to elucidate more completely the genetic basis of AMD.

  14. An ex-vivo human intestinal model to study Entamoeba histolytica pathogenesis.

    Directory of Open Access Journals (Sweden)

    Devendra Bansal

    Full Text Available Amoebiasis (a human intestinal infection affecting 50 million people every year is caused by the protozoan parasite Entamoeba histolytica. To study the molecular mechanisms underlying human colon invasion by E. histolytica, we have set up an ex vivo human colon model to study the early steps in amoebiasis. Using scanning electron microscopy and histological analyses, we have established that E. histolytica caused the removal of the protective mucus coat during the first two hours of incubation, detached the enterocytes, and then penetrated into the lamina propria by following the crypts of Lieberkühn. Significant cell lysis (determined by the release of lactodehydrogenase and inflammation (marked by the secretion of pro-inflammatory molecules such as interleukin 1 beta, interferon gamma, interleukin 6, interleukin 8 and tumour necrosis factor were detected after four hours of incubation. Entamoeba dispar (a closely related non-pathogenic amoeba that also colonizes the human colon was unable to invade colonic mucosa, lyse cells or induce an inflammatory response. We also examined the behaviour of trophozoites in which genes coding for known virulent factors (such as amoebapores, the Gal/GalNAc lectin and the cysteine protease 5 (CP-A5, which have major roles in cell death, adhesion (to target cells or mucus and mucus degradation, respectively were silenced, together with the corresponding tissue responses. Our data revealed that the signalling via the heavy chain Hgl2 or via the light chain Lgl1 of the Gal/GalNAc lectin is not essential to penetrate the human colonic mucosa. In addition, our study demonstrates that E. histolytica silenced for CP-A5 does not penetrate the colonic lamina propria and does not induce the host's pro-inflammatory cytokine secretion.

  15. Atg8 is involved in endosomal and phagosomal acidification in the parasitic protist Entamoeba histolytica.

    Science.gov (United States)

    Picazarri, Karina; Nakada-Tsukui, Kumiko; Tsuboi, Kumiko; Miyamoto, Eri; Watanabe, Naoko; Kawakami, Eiryo; Nozaki, Tomoyoshi

    2015-10-01

    Autophagy is one of two major bulk protein degradation systems and is conserved throughout eukaryotes. The protozoan Entamoeba histolytica, which is a human intestinal parasite, possesses a restricted set of autophagy-related (Atg) proteins compared with other eukaryotes and thus represents a suitable model organism for studying the minimal essential components and ancestral functions of autophagy. E. histolytica possesses two conjugation systems: Atg8 and Atg5/12, although a gene encoding Atg12 is missing in the genome. Atg8 is considered to be the central and authentic marker of autophagosomes, but recent studies have demonstrated that Atg8 is not exclusively involved in autophagy per se, but other fundamental mechanisms of vesicular traffic. To investigate this question in E. histolytica, we studied on Atg8 during the proliferative stage. Atg8 was constitutively expressed in both laboratory-maintained and recently established clinical isolates and appeared to be lipid-modified in logarithmic growth phase, suggesting a role of Atg8 in non-stress and proliferative conditions. These findings are in contrast to those for Entamoeba invadens, in which autophagy is markedly induced during an early phase of differentiation from the trophozoite into the cyst. The repression of Atg8 gene expression in En. histolytica by antisense small RNA-mediated transcriptional gene silencing resulted in growth retardation, delayed endocytosis and reduced acidification of endosomes and phagosomes. Taken together, these results suggest that Atg8 and the Atg8 conjugation pathway have some roles in the biogenesis of endosomes and phagosomes in this primitive eukaryote.

  16. An ex-vivo human intestinal model to study Entamoeba histolytica pathogenesis.

    Science.gov (United States)

    Bansal, Devendra; Ave, Patrick; Kerneis, Sophie; Frileux, Pascal; Boché, Olivier; Baglin, Anne Catherine; Dubost, Geneviève; Leguern, Anne-Sophie; Prevost, Marie-Christine; Bracha, Rivka; Mirelman, David; Guillén, Nancy; Labruyère, Elisabeth

    2009-11-17

    Amoebiasis (a human intestinal infection affecting 50 million people every year) is caused by the protozoan parasite Entamoeba histolytica. To study the molecular mechanisms underlying human colon invasion by E. histolytica, we have set up an ex vivo human colon model to study the early steps in amoebiasis. Using scanning electron microscopy and histological analyses, we have established that E. histolytica caused the removal of the protective mucus coat during the first two hours of incubation, detached the enterocytes, and then penetrated into the lamina propria by following the crypts of Lieberkühn. Significant cell lysis (determined by the release of lactodehydrogenase) and inflammation (marked by the secretion of pro-inflammatory molecules such as interleukin 1 beta, interferon gamma, interleukin 6, interleukin 8 and tumour necrosis factor) were detected after four hours of incubation. Entamoeba dispar (a closely related non-pathogenic amoeba that also colonizes the human colon) was unable to invade colonic mucosa, lyse cells or induce an inflammatory response. We also examined the behaviour of trophozoites in which genes coding for known virulent factors (such as amoebapores, the Gal/GalNAc lectin and the cysteine protease 5 (CP-A5), which have major roles in cell death, adhesion (to target cells or mucus) and mucus degradation, respectively) were silenced, together with the corresponding tissue responses. Our data revealed that the signalling via the heavy chain Hgl2 or via the light chain Lgl1 of the Gal/GalNAc lectin is not essential to penetrate the human colonic mucosa. In addition, our study demonstrates that E. histolytica silenced for CP-A5 does not penetrate the colonic lamina propria and does not induce the host's pro-inflammatory cytokine secretion.

  17. Vascular related pregnancy complications: genetics and remote cardiovascular risk

    NARCIS (Netherlands)

    A.L. Berends (Anne)

    2008-01-01

    textabstractPreeclampsia and intrauterine growth restriction (IUGR) are common vascular related pregnancy syndromes of unknown cause. Both preeclampsia and IUGR are responsible for a significant maternal and perinatal morbidity and mortality worldwide. Preeclampsia affects approximately 2.5-3.0% of

  18. Age-related maculopathy: A genetic and epidemiological approach

    NARCIS (Netherlands)

    J.J.M. Willemse-Assink (Jacqueline)

    2000-01-01

    textabstractIn the 19th century, age-related maculopathy (ARM) was described for the first time as an agerelated abnormality of the macula lutea. ARM consists of a variety of clinical signs, from the early stages with soft distinct drusen, indistinct drusen and pigment alterations up to the late st

  19. Genotyping of Giardia lamblia and Entamoeba spp from river waters in Iran.

    Science.gov (United States)

    Mahmoudi, Mohammad Reza; Nazemalhosseini-Mojarad, Ehsan; Karanis, Panagiotis

    2015-12-01

    In this study, DNA from 55 surface and river water samples, which were collected from some water sources of Tehran and the Guilan Province, Iran, were extracted and examined for Entamoeba spp. and Giardia lamblia by PCR and genotyping. Twenty-seven samples, which were concentrated using the immunomagnetic separation technology (IMS) method, were examined for Giardia alone. Twenty-eight samples, which were concentrated using the sucrose flotation (SF) method, were examined for both Giardia and Entamoeba species. The results showed that 27/55 (17/27 and 10/28) (49 %), 4 /28 (14.28 %) and 3/28 (10.7 %) of the samples were positive for Giardia lamblia, Entamoeba spp and mixed infections (Entamoeba spp. and Giardia spp.), respectively. Sixteen out of 55 samples were negative. Entamoeba genus-specific PCR primers in single-round PCR were used to differentiate between the Entamoeba spp. (E. histolytica, E. dispar and E. moshkovskii). With respect to the 7 samples that were positive for Entamoeba, (14.28 %) 4 out of 28 were positive for E. moshkovskii, (7.14 %), 2 out of 28 were positive for E. histolytica and (3.57 %) 1 out of 28 was positive for E. dispar. Genus-specific PCR primers in a semi-nested PCR assay was performed to genotype Giardia species. Of the 27 samples that were positive for Giardia, 10 samples were sequences. All 10 successfully sequenced samples contained assemblage B of Giardia lamblia.This is first study to investigate the G. lamblia genotypes in the water supply of the Tehran and Guilan provinces, and it is the first study to investigate Entamoeba species in the water supplies of Iran. The investigated river water supplies, which are used for agriculture, camping and animal farming, were heavily contaminated by the human pathogenic Entamoeba and Giardia parasites. There is a potential risk of waterborne outbreaks in humans and animals.

  20. Characteristics of genetics-related news content in Black weekly newspapers.

    Science.gov (United States)

    Caburnay, C A; Babb, P; Kaphingst, K A; Roberts, J; Rath, S

    2014-01-01

    BACKGROUND/AIMS/OBJECTIVES: The media are an important source of health information, especially for those with less access to regular health care. Black news outlets such as Black newspapers are a source of health information for African Americans. This study characterized media coverage of genetics-related information in Black weekly newspapers and general audience newspapers from the same communities. All health stories in a sample of 24 Black weekly newspapers and 12 general audience newspapers from January 2004 to December 2007 were reviewed for genetics-related stories. These stories were further coded for both journalistic and public health variables. Of all health-related stories identified, only 2% (n = 357) were considered genetics related. Genetics-related stories in Black newspapers - compared to those in general audience newspapers - were larger, more locally and racially relevant, and more likely to contain recommendations or action steps to improve health or reduce disease risks and to mention the importance of knowing one's family history. Stories in general audience newspapers were more likely to discuss causes of disease, mention genetic testing or therapy, and suggest a high/moderate degree of genetic determinism. Black newspapers are a viable communication channel to disseminate findings and implications of human genome research to African American audiences.

  1. Genetic factors that increase male facial masculinity decrease facial attractiveness of female relatives.

    Science.gov (United States)

    Lee, Anthony J; Mitchem, Dorian G; Wright, Margaret J; Martin, Nicholas G; Keller, Matthew C; Zietsch, Brendan P

    2014-02-01

    For women, choosing a facially masculine man as a mate is thought to confer genetic benefits to offspring. Crucial assumptions of this hypothesis have not been adequately tested. It has been assumed that variation in facial masculinity is due to genetic variation and that genetic factors that increase male facial masculinity do not increase facial masculinity in female relatives. We objectively quantified the facial masculinity in photos of identical (n = 411) and nonidentical (n = 782) twins and their siblings (n = 106). Using biometrical modeling, we found that much of the variation in male and female facial masculinity is genetic. However, we also found that masculinity of male faces is unrelated to their attractiveness and that facially masculine men tend to have facially masculine, less-attractive sisters. These findings challenge the idea that facially masculine men provide net genetic benefits to offspring and call into question this popular theoretical framework.

  2. Genetics of ischemic stroke, stroke-related risk factors, stroke precursors and treatments.

    Science.gov (United States)

    Della-Morte, David; Guadagni, Fiorella; Palmirotta, Raffaele; Testa, Gianluca; Caso, Valeria; Paciaroni, Maurizio; Abete, Pasquale; Rengo, Franco; Ferroni, Patrizia; Sacco, Ralph L; Rundek, Tatjana

    2012-04-01

    Stroke remains a leading cause of death worldwide and the first cause of disability in the western world. Ischemic stroke (IS) accounts for almost 80% of the total cases of strokes and is a complex and multifactorial disease caused by the combination of vascular risk factors, environment and genetic factors. Investigations of the genetics of atherosclerosis and IS has greatly enhanced our knowledge of this complex multifactorial disease. In this article we sought to review common single-gene disorders relevant to IS, summarize candidate gene and genome-wide studies aimed at discovering genetic stroke risk factors and subclinical phenotypes, and to briefly discuss pharmacogenetics related to stroke treatments. Genetics of IS is, in fact, one of the most promising research frontiers and genetic testing may be helpful for novel drug discoveries as well as for appropriate drug and dose selection for treatment of patients with cerebrovascular disease.

  3. Genetic rescue of an endangered domestic animal through outcrossing with closely related breeds

    DEFF Research Database (Denmark)

    Strønen, Astrid Vik; Salmela, Elina; Baldursdottir, Birna K.

    2017-01-01

    Genetic rescue, outcrossing with individuals from a related population, is used to augment genetic diversity in populations threatened by severe inbreeding and extinction. The endangered Norwegian Lundehund dog underwent at least two severe bottlenecks in the 1940s and 1960s that each left only......: Norwegian Buhund, Icelandic Sheepdog, and Norrbottenspets. Examination of single nucleotide polymorphism (SNP) genotypes based on 165K loci in 48 dogs from the four breeds revealed substantially lower genetic diversity for the Lundehund (HE 0.035) than for other breeds (HE 0.209-0.284). Analyses of genetic...... structure with > 15K linkage disequilibrium-pruned SNPs showed four distinct genetic clusters. Pairwise FST values between Lundehund and the candidate breeds were highest for Icelandic Sheepdog, followed by Buhund and Norrbottenspets. We assessed the presence of outlier loci among candidate breeds...

  4. The relative importance of genetic and environmental effects for the early stages of thyroid autoimmunity

    DEFF Research Database (Denmark)

    Hansen, Pia S; Brix, Thomas H; Iachine, Ivan;

    2006-01-01

    OBJECTIVE: In euthyroid individuals, autoantibodies to thyroid peroxidase (TPOab) and thyroglobulin (Tgab) are regarded as early markers of thyroid autoimmunity. Family and twin studies suggest that development of thyroid autoantibodies in first-degree relatives of patients with autoimmune thyroid...... disease is under genetic influence. We aimed to estimate the relative importance of genetic and environmental effects for the presence of thyroid autoantibodies in euthyroid subjects. METHODS: A representative sample of healthy twin pairs was identified through the Danish Twin Registry; 1372 individuals...... concordance and intraclass correlations were consistently higher for MZ than for DZ twin pairs indicating genetic influence. Genetic components (with 95% confidence intervals) accounted for 73% (46-89%) of the liability of being thyroid antibody positive. Adjusting for covariates (age, TSH and others...

  5. Genetic variants in hormone-related genes and risk of breast cancer.

    Directory of Open Access Journals (Sweden)

    Tess Clendenen

    Full Text Available Sex hormones play a key role in the development of breast cancer. Certain polymorphic variants (SNPs and repeat polymorphisms in hormone-related genes are associated with sex hormone levels. However, the relationship observed between these genetic variants and breast cancer risk has been inconsistent. We conducted a case-control study nested within two prospective cohorts to assess the relationship between specific genetic variants in hormone-related genes and breast cancer risk. In total, 1164 cases and 2111 individually-matched controls were included in the study. We did not observe an association between potential functional genetic polymorphisms in the estrogen pathway, SHBG rs6259, ESR1 rs2234693, CYP19 rs10046 and rs4775936, and UGT1A1 rs8175347, or the progesterone pathway, PGR rs1042838, with the risk of breast cancer. Our results suggest that these genetic variants do not have a strong effect on breast cancer risk.

  6. Interest in Genetic Testing in Ashkenazi Jewish Parkinson’s Disease Patients and Their Unaffected Relatives

    OpenAIRE

    2014-01-01

    Our objective was to explore interest in genetic testing among Ashkenazi Jewish (AJ) Parkinson’s Disease (PD) cases and first-degree relatives, as genetic testing for LRRK2 G2019S is widely available. Approximately 18 % of AJ PD cases carry G2019S mutations; penetrance estimations vary between 24 and 100 % by age 80. A Genetic Attitude Questionnaire (GAQ) was administered at two New York sites to PD families unaware of LRRK2 G2019S mutation status. The association of G2019S, age, education, g...

  7. [Constant or break? On the relations between human genetics and eugenics in the Twentieth Century].

    Science.gov (United States)

    Germann, Pascal

    2015-07-01

    The history of human genetics has been a neglected topic in history of science and medicine for a long time. Only recently, have medical historians begun to pay more attention to the history of human heredity. An important research question deals with the interconnections between human genetics and eugenics. This paper addresses this question: By focusing on a Swiss case study, the investigation of the heredity of goiter, I will argue that there existed close but also ambiguous relations between heredity research and eugenics in the twentieth century. Studies on human heredity often produced evidence that challenged eugenic aims and ideas. Concurrently, however, these studies fostered visions of genetic improvement of human populations.

  8. Eponyms related to genetic disorders associated with gingival enlargement; part II

    Directory of Open Access Journals (Sweden)

    Nora Mohammed Al-Aboud

    2015-01-01

    Full Text Available There are genetic disorders associated with gingival enlargement. In our part I, we reviewed the eponyms linked to Hereditary Gingival Fibromatosis (HGF [1]. Historical Article How to cite this article: Al Aboud A, Al-Aboud NM, Barnawi H, Al Hakami A. Eponyms related to genetic disorders associated with gingival enlargement: Part II. Our Dermatol Online. 2015;6(1:114-117. Submission: 27.05.2013; Acceptance: 21.09.2014 DOI: 10.7241/ourd.20151.32 In this part II of this review, we are going to shed some light on eponyms linked to groups of genetic disorders which may feature gingival enlargement.

  9. The Application of Genetic Risk Scores in Age-Related Macular Degeneration: A Review

    Directory of Open Access Journals (Sweden)

    Jessica N. Cooke Bailey

    2016-03-01

    Full Text Available Age-related macular degeneration (AMD, a highly prevalent and impactful disease of aging, is inarguably influenced by complex interactions between genetic and environmental factors. Various risk scores have been tested that assess measurable genetic and environmental contributions to disease. We herein summarize and review the ability and utility of these numerous models for prediction of AMD and suggest additional risk factors to be incorporated into clinically useful predictive models of AMD.

  10. Genetic and Environmental Etiologies of the Longitudinal Relations between Prereading Skills and Reading

    Science.gov (United States)

    Christopher, Micaela E.; Hulslander, Jacqueline; Byrne, Brian; Samuelsson, Stefan; Keenan, Janice M.; Pennington, Bruce; DeFries, John C.; Wadsworth, Sally J.; Willcutt, Erik; Olson, Richard K.

    2015-01-01

    The present study explored the environmental and genetic etiologies of the longitudinal relations between prereading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post-first grade (M = 7.4 years), and post-fourth grade (M = 10.4 years). Genetic influences on five prereading skills (print…

  11. Genetic and Environmental Etiologies of the Longitudinal Relations between Prereading Skills and Reading

    Science.gov (United States)

    Christopher, Micaela E.; Hulslander, Jacqueline; Byrne, Brian; Samuelsson, Stefan; Keenan, Janice M.; Pennington, Bruce; DeFries, John C.; Wadsworth, Sally J.; Willcutt, Erik; Olson, Richard K.

    2015-01-01

    The present study explored the environmental and genetic etiologies of the longitudinal relations between prereading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post-first grade (M = 7.4 years), and post-fourth grade (M = 10.4 years). Genetic influences on five prereading skills (print…

  12. Differential distribution of a SINE element in the Entamoeba histolytica and Entamoeba dispar genomes: Role of the LINE-encoded endonuclease

    Directory of Open Access Journals (Sweden)

    Gupta Abhishek K

    2011-05-01

    Full Text Available Abstract Background Entamoeba histolytica and Entamoeba dispar are closely related protistan parasites but while E. histolytica can be invasive, E. dispar is completely non pathogenic. Transposable elements constitute a significant portion of the genome in these species; there being three families of LINEs and SINEs. These elements can profoundly influence the expression of neighboring genes. Thus their genomic location can have important phenotypic consequences. A genome-wide comparison of the location of these elements in the E. histolytica and E. dispar genomes has not been carried out. It is also not known whether the retrotransposition machinery works similarly in both species. The present study was undertaken to address these issues. Results Here we extracted all genomic occurrences of full-length copies of EhSINE1 in the E. histolytica genome and matched them with the homologous regions in E. dispar, and vice versa, wherever it was possible to establish synteny. We found that only about 20% of syntenic sites were occupied by SINE1 in both species. We checked whether the different genomic location in the two species was due to differences in the activity of the LINE-encoded endonuclease which is required for nicking the target site. We found that the endonucleases of both species were essentially very similar, both in their kinetic properties and in their substrate sequence specificity. Hence the differential distribution of SINEs in these species is not likely to be influenced by the endonuclease. Further we found that the physical properties of the DNA sequences adjoining the insertion sites were similar in both species. Conclusions Our data shows that the basic retrotransposition machinery is conserved in these sibling species. SINEs may indeed have occupied all of the insertion sites in the genome of the common ancestor of E. histolytica and E. dispar but these may have been subsequently lost from some locations. Alternatively, SINE

  13. Construction of a genetic linkage map and genetic analysis of domestication related traits in mungbean (Vigna radiata.

    Directory of Open Access Journals (Sweden)

    Takehisa Isemura

    Full Text Available The genetic differences between mungbean and its presumed wild ancestor were analyzed for domestication related traits by QTL mapping. A genetic linkage map of mungbean was constructed using 430 SSR and EST-SSR markers from mungbean and its related species, and all these markers were mapped onto 11 linkage groups spanning a total of 727.6 cM. The present mungbean map is the first map where the number of linkage groups coincided with the haploid chromosome number of mungbean. In total 105 QTLs and genes for 38 domestication related traits were identified. Compared with the situation in other Vigna crops, many linkage groups have played an important role in the domestication of mungbean. In particular the QTLs with high contribution were distributed on seven out of 11 linkage groups. In addition, a large number of QTLs with small contribution were found. The accumulation of many mutations with large and/or small contribution has contributed to the differentiation between wild and cultivated mungbean. The useful QTLs for seed size, pod dehiscence and pod maturity that have not been found in other Asian Vigna species were identified in mungbean, and these QTLs may play the important role as new gene resources for other Asian Vigna species. The results provide the foundation that will be useful for improvement of mungbean and related legumes.

  14. Cause and effect analysis by fuzzy relational equations and a genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Rotshtein, Alexander P. [Industrial Engineering and Management Department, Jerusalem College of Technology-Machon Lev, Havaad Haleumi St., 21, 91160, Jerusalem (Israel)]. E-mail: rot@jct.ac.il; Posner, Morton [Industrial Engineering and Management Department, Jerusalem College of Technology-Machon Lev, Havaad Haleumi St., 21, 91160, Jerusalem (Israel); Rakytyanska, Hanna B. [Department of Applied Mathematics, Vinnitsa State Technical University, Khmelnitske Sh., 95, 21021, Vinnitsa (Ukraine)]. E-mail: h_rakit@hotmail.com

    2006-09-15

    This paper proposes using a genetic algorithm as a tool to solve the fault diagnosis problem. The fault diagnosis problem is based on a cause and effect analysis which is formally described by fuzzy relations. Fuzzy relations are formed on the basis of expert assessments. Application of expert fuzzy relations to restore and identify the causes through the observed effects requires the solution to a system of fuzzy relational equations. In this study this search for a solution amounts to solving a corresponding optimization problem. An optimization algorithm is based on the application of genetic operations of crossover, mutation and selection. The genetic algorithm suggested here represents an application in expert systems of fault diagnosis and quality control.

  15. Genetic Evidence for Causal Relationships Between Maternal Obesity-Related Traits and Birth Weight

    DEFF Research Database (Denmark)

    Tyrrell, Jessica; Richmond, Rebecca C; Palmer, Tom M

    2016-01-01

    IMPORTANCE: Neonates born to overweight or obese women are larger and at higher risk of birth complications. Many maternal obesity-related traits are observationally associated with birth weight, but the causal nature of these associations is uncertain. OBJECTIVE: To test for genetic evidence...... of causal associations of maternal body mass index (BMI) and related traits with birth weight. DESIGN, SETTING, AND PARTICIPANTS: Mendelian randomization to test whether maternal BMI and obesity-related traits are potentially causally related to offspring birth weight. Data from 30,487 women in 18 studies...... were analyzed. Participants were of European ancestry from population- or community-based studies in Europe, North America, or Australia and were part of the Early Growth Genetics Consortium. Live, term, singleton offspring born between 1929 and 2013 were included. EXPOSURES: Genetic scores for BMI...

  16. The effect and relative importance of neutral genetic diversity for predicting parasitism varies across parasite taxa.

    Directory of Open Access Journals (Sweden)

    María José Ruiz-López

    Full Text Available Understanding factors that determine heterogeneity in levels of parasitism across individuals is a major challenge in disease ecology. It is known that genetic makeup plays an important role in infection likelihood, but the mechanism remains unclear as does its relative importance when compared to other factors. We analyzed relationships between genetic diversity and macroparasites in outbred, free-ranging populations of raccoons (Procyon lotor. We measured heterozygosity at 14 microsatellite loci and modeled the effects of both multi-locus and single-locus heterozygosity on parasitism using an information theoretic approach and including non-genetic factors that are known to influence the likelihood of parasitism. The association of genetic diversity and parasitism, as well as the relative importance of genetic diversity, differed by parasitic group. Endoparasite species richness was better predicted by a model that included genetic diversity, with the more heterozygous hosts harboring fewer endoparasite species. Genetic diversity was also important in predicting abundance of replete ticks (Dermacentor variabilis. This association fit a curvilinear trend, with hosts that had either high or low levels of heterozygosity harboring fewer parasites than those with intermediate levels. In contrast, genetic diversity was not important in predicting abundance of non-replete ticks and lice (Trichodectes octomaculatus. No strong single-locus effects were observed for either endoparasites or replete ticks. Our results suggest that in outbred populations multi-locus diversity might be important for coping with parasitism. The differences in the relationships between heterozygosity and parasitism for the different parasites suggest that the role of genetic diversity varies with parasite-mediated selective pressures.

  17. The effect of close relatives on unsupervised Bayesian clustering algorithms in population genetic structure analysis.

    Science.gov (United States)

    Rodríguez-Ramilo, Silvia T; Wang, Jinliang

    2012-09-01

    The inference of population genetic structures is essential in many research areas in population genetics, conservation biology and evolutionary biology. Recently, unsupervised Bayesian clustering algorithms have been developed to detect a hidden population structure from genotypic data, assuming among others that individuals taken from the population are unrelated. Under this assumption, markers in a sample taken from a subpopulation can be considered to be in Hardy-Weinberg and linkage equilibrium. However, close relatives might be sampled from the same subpopulation, and consequently, might cause Hardy-Weinberg and linkage disequilibrium and thus bias a population genetic structure analysis. In this study, we used simulated and real data to investigate the impact of close relatives in a sample on Bayesian population structure analysis. We also showed that, when close relatives were identified by a pedigree reconstruction approach and removed, the accuracy of a population genetic structure analysis can be greatly improved. The results indicate that unsupervised Bayesian clustering algorithms cannot be used blindly to detect genetic structure in a sample with closely related individuals. Rather, when closely related individuals are suspected to be frequent in a sample, these individuals should be first identified and removed before conducting a population structure analysis.

  18. Detection and differentiation of Entamoeba histolytica and Entamoeba dispar in clinical samples through PCR-denaturing gradient gel electrophoresis

    Directory of Open Access Journals (Sweden)

    P. López-López

    Full Text Available Amebiasis is one of the twenty major causes of disease in Mexico; however, the diagnosis is difficult due to limitations of conventional microscopy-based techniques. In this study, we analyzed stool samples using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE to differentiate between Entamoeba histolytica (pathogenic and E. dispar (non-pathogenic. The target for the PCR amplification was a small region (228 bp of the adh112 gene selected to increase the sensitivity of the test. The study involved 62 stool samples that were collected from individuals with complaints of gastrointestinal discomfort. Of the 62 samples, 10 (16.1% were positive for E. histolytica while 52 (83.9% were negative. No sample was positive for E. dispar. These results were validated by nested PCR-RFLP (restriction fragment length polymorphism and suggest that PCR-DGGE is a promising tool to differentiate among Entamoeba infections, contributing to determine the specific treatment for patients infected with E. histolytica, and therefore, avoiding unnecessary treatment of patients infected with the non-pathogenic E. dispar.

  19. [Detection and differentiation of Entamoeba histolytica and Entamoeba dispar by polymerase chain reaction in a community in Zulia State, Venezuela].

    Science.gov (United States)

    Rivero, Zulbey; Bracho, Angela; Calchi, Marinella; Díaz, Iris; Acurero, Ellen; Maldonado, Adriana; Chourio, Glenis; Arráiz, Nailet; Corzo, Gilbert

    2009-01-01

    Differential identification of Entamoeba histolytica and Entamoeba dispar is essential for both appropriate patient treatment and epidemiological purposes. To determine the prevalence of these amoeba infections in Santa Rosa de Agua (Maracaibo, Zulia State, Venezuela), a PCR assay using specific primers for each species was standardized and applied. 204 stool samples were analyzed through direct microscopic examination with SSF (0.85%) and lugol, formol-ether concentration, and PCR. Under direct microscopy, 42 individuals (20.58%) presented the E. histolytica/E. dispar complex. Meanwhile PCR showed 47 positive cases for these amoebas: 22 E. histolytica (10.78%), 16 E. dispar (7.84%), and 9 (4.41%) mixed infections. There was no significant difference in the presence of E. histolytica and/or E. dispar according to either gender or age. There were no cases of these amoebas in children under 2 years of age. Observed frequency of E. histolytica (31/204) shows the endemic nature of amoeba infection in this community.

  20. Detection and differentiation of Entamoeba histolytica and Entamoeba dispar in clinical samples through PCR-denaturing gradient gel electrophoresis.

    Science.gov (United States)

    López-López, P; Martínez-López, M C; Boldo-León, X M; Hernández-Díaz, Y; González-Castro, T B; Tovilla-Zárate, C A; Luna-Arias, J P

    2017-04-03

    Amebiasis is one of the twenty major causes of disease in Mexico; however, the diagnosis is difficult due to limitations of conventional microscopy-based techniques. In this study, we analyzed stool samples using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to differentiate between Entamoeba histolytica (pathogenic) and E. dispar (non-pathogenic). The target for the PCR amplification was a small region (228 bp) of the adh112 gene selected to increase the sensitivity of the test. The study involved 62 stool samples that were collected from individuals with complaints of gastrointestinal discomfort. Of the 62 samples, 10 (16.1%) were positive for E. histolytica while 52 (83.9%) were negative. No sample was positive for E. dispar. These results were validated by nested PCR-RFLP (restriction fragment length polymorphism) and suggest that PCR-DGGE is a promising tool to differentiate among Entamoeba infections, contributing to determine the specific treatment for patients infected with E. histolytica, and therefore, avoiding unnecessary treatment of patients infected with the non-pathogenic E. dispar.

  1. Genetic recombination in Escherichia coli : I. Relation between linkage of unselected markers and map distance

    NARCIS (Netherlands)

    Verhoef, C.; Haan, P.G. de

    1966-01-01

    A relation between linkage frequency of an unselected marker and transfer time based on a physical exchange of genetic material was developed for Escherichia coli crosses. Crosses performed under standardised conditions have shown that the relation was valid. The linkage frequency is determined by t

  2. Entamoeba histolytica Infection in Children Aged 0-12 Years in ...

    African Journals Online (AJOL)

    Entamoeba histolytica Infection in Children Aged 0-12 Years in Rural ... in a list of communicable and non-communicable diseases affecting school-age ... East Local Government Area, a rural setting in Anambra State, southeast Nigeria.

  3. Genetic testing for inherited heart diseases: longitudinal impact on health-related quality of life.

    Science.gov (United States)

    Ingles, Jodie; Yeates, Laura; O'Brien, Lisa; McGaughran, Julie; Scuffham, Paul A; Atherton, John; Semsarian, Christopher

    2012-05-03

    Purpose:A genetic diagnosis is an extremely useful tool in the management and care of families with inherited heart diseases, particularly in allowing clarification of risk status of asymptomatic family members. The psychosocial consequences of genetic testing in this group are poorly understood. This longitudinal pilot study sought to determine changes in health-related quality of life in patients and asymptomatic family members undergoing genetic testing for inherited heart diseases.Methods:Individuals attending two specialized multidisciplinary cardiac genetic clinics in Australia were invited to participate. Patients undergoing proband or predictive genetic testing for an inherited cardiomyopathy or primary arrhythmogenic disorder were eligible. The Medical Outcomes Short Form-36 (version 2) was administered before the genetic result was given, and follow-up surveys were completed 1-3, 6, and 12 months after the result was given.Results:A total of 54 individuals with hypertrophic cardiomyopathy, familial dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and long QT syndrome completed baseline and at least one follow-up survey, including 33 probands and 21 asymptomatic relatives. Physical and mental component scores analyzed at baseline and 1-3 months were found to be unchanged in all groups. Furthermore, no significant differences were observed up to 12 months after result.Conclusion:In this longitudinal pilot study, no change in health-related quality of life was observed up to 12 months after the result was given in patients and their asymptomatic family members undergoing genetic testing for an inherited heart disease.Genet Med 2012 advance online publication 3 May 2012.

  4. Correlation between genotypes of tRNA-linked short tandem repeats in Entamoeba nuttalli isolates and the geographical distribution of host rhesus macaques.

    Science.gov (United States)

    Feng, Meng; Komiyama, Tomoyoshi; Yanagi, Tetsuo; Cheng, Xunjia; Sherchand, Jeevan B; Tachibana, Hiroshi

    2014-01-01

    Several polymorphic markers, including serine-rich protein genes, have been used for the genotyping of isolates from the morphologically indistinguishable protozoan parasites Entamoeba histolytica, Entamoeba dispar, and Entamoeba nuttalli. Genotypes of tRNA-linked short tandem repeats (STRs) are highly polymorphic, but the correlation with geographical distribution is unknown. We have recently isolated 15 E. nuttalli strains from wild rhesus macaques in four locations in Kathmandu Valley, Nepal. The sequences of the serine-rich protein genes of the E. nuttalli strains differed among the four locations. In this study, we analyzed tRNA-linked STRs in six loci of the 15 strains. Two genotypes were found in loci N-K2, R-R, and S(TGA)-D, three in locus S-Q, and five in locus D-A. In locus A-L, one major genotype and ten minor genotypes were found, resulting in mixtures of two to six genotypes in eight strains. By combination of the main genotypes in the six loci, the 15 strains were divided into nine genotypes. The genotypes observed in E. nuttalli strains were quite different from those in E. histolytica and E. dispar. A phylogenetic tree constructed from tRNA-linked STRs in the six loci reflected the different places of isolation. These results suggest that sequence diversity of tRNA-linked STRs in E. nuttalli occurs with relatively high frequency and might be a marker of geographical distribution of host rhesus macaques, even in limited areas.

  5. A mutation in the leptin receptor is associated with Entamoeba histolytica infection in children

    Science.gov (United States)

    Duggal, Priya; Guo, Xiaoti; Haque, Rashidul; Peterson, Kristine M.; Ricklefs, Stacy; Mondal, Dinesh; Alam, Faisal; Noor, Zannatun; Verkerke, Hans P.; Marie, Chelsea; Leduc, Charles A.; Jr., Streamson C. Chua; Jr., Martin G. Myers; Leibel, Rudolph L.; Houpt, Eric; Gilchrist, Carol A.; Sher, Alan; Porcella, Stephen F.; Jr., William A. Petri

    2011-01-01

    Malnutrition substantially increases susceptibility to Entamoeba histolytica in children. Leptin is a hormone produced by adipocytes that inhibits food intake, influences the immune system, and is suppressed in malnourished children. Therefore we hypothesized that diminished leptin function may increase susceptibility to E. histolytica infection. We prospectively observed a cohort of children, beginning at preschool age, for infection by the parasite E. histolytica every other day over 9 years and evaluated them for genetic variants in leptin (LEP) and the leptin receptor (LEPR). We found increased susceptibility to intestinal infection by this parasite associated with an amino acid substitution in the cytokine receptor homology domain 1 of LEPR. Children carrying the allele for arginine (223R) were nearly 4 times more likely to have an infection compared with those homozygous for the ancestral glutamine allele (223Q). An association of this allele with amebic liver abscess was also determined in an independent cohort of adult patients. In addition, mice carrying at least 1 copy of the R allele of Lepr were more susceptible to infection and exhibited greater levels of mucosal destruction and intestinal epithelial apoptosis after amebic infection. These findings suggest that leptin signaling is important in mucosal defense against amebiasis and that polymorphisms in the leptin receptor explain differences in susceptibility of children in the Bangladesh cohort to amebiasis. PMID:21393862

  6. [Importance of Trichomonas tenax and Entamoeba gingivalis protozoa in the human oral cavity].

    Science.gov (United States)

    Feki, A; Molet, B

    1990-01-01

    Trichomonas tenax and Entamoeba gingivalis are protozoa found in the human oral cavity. Morphological and ultrastructural characteristics of those parasites were reviewed and then studied with the scanning electron microscope in this paper. Based on previous epidemiological studies, the relationship between periodontal disease and those protozoa was analysed. Evaluation of the pathogenicity of Trichomonas tenax and Entamoeba gingivalis was also part of the discussion of this study.

  7. Prevalence of Entamoeba species in captive primates in zoological gardens in the UK

    Directory of Open Access Journals (Sweden)

    Carl S. Regan

    2014-07-01

    Full Text Available The aim of this study was to determine the prevalence of amoebic infection in non-human primates (NHPs from six Zoological gardens in the United Kingdom. Initially, 126 faecal samples were collected from 37 individually identified NHPs at Twycross Zoo, UK, and were subjected to microscopic examination. A subsequent, nationwide experiment included 350 faecal samples from 89 individually identified NHPs and 73 unidentified NHPs from a number of UK captive wildlife facilities: Twycross Zoo (n = 60, Colchester Zoo (n = 3, Edinburgh Zoo (n = 6, Port Lympne Wild Animal Park (n = 58, Howletts Wild Animal Park (n = 31, and Cotswold Wildlife Park (n = 4. Samples were examined by PCR and sequencing using four specific primer sets designed to differentiate between the pathogenic E. histolytica, the non-pathogenic E. dispar, and non-pathogenic uninucleate cyst-producing Entamoeba species. In the first experiment, Entamoeba was detected in 30 primates (81.1%. Six (16.2% primates were infected with E. histolytica species complex. The highest carriage of Entamoeba species was found in Old World Colobinae primates. In the nationwide experiment, molecular analysis of faecal samples revealed notable rates of Entamoeba infection (101 samples, 28.9%, including one sample infected with E. histolytica, 14 samples with E. dispar, and 86 samples with uninucleated-cyst producing Entamoeba species. Sequences of positive uninucleated-cyst producing Entamoeba samples from Twycross Zoo clustered with the E. polecki reference sequences ST4 reported in Homo sapiens, and are widely separated from other Entamoeba species. These findings suggest a low prevalence of the pathogenic Entamoeba infection, but notable prevalence of non-pathogenic E. polecki infection in NHPs in the UK.

  8. Entamoeba dispar: A Rare Case of Enteritis in a Patient Living in a Nonendemic Area

    Directory of Open Access Journals (Sweden)

    Rosalia Graffeo

    2014-01-01

    Full Text Available Entamoeba dispar, a common noninvasive parasite, is indistinguishable in its cysts and trophozoite forms from Entamoeba histolytica, the cause of invasive amebiasis, by microscopy. To differentiate the two species seems to be a problem for laboratory diagnosis. Recent experimental studies showed that  E. dispar can be considered pathogenic too. We present a rare case of enteritis due to E. dispar.

  9. Recent advances in Entamoeba biology: RNA interference, drug discovery, and gut microbiome.

    Science.gov (United States)

    Morgado, Pedro; Manna, Dipak; Singh, Upinder

    2016-01-01

    In recent years, substantial progress has been made in understanding the molecular and cell biology of the human parasite Entamoeba histolytica, an important pathogen with significant global impact. This review outlines some recent advances in the Entamoeba field in the last five years, focusing on areas that have not recently been discussed in detail: (i) molecular mechanisms regulating parasite gene expression, (ii) new efforts at drug discovery using high-throughput drug screens, and (iii) the effect of gut microbiota on amoebiasis.

  10. Investigation of Entamoeba histolytica in stool specimens by ELISA during a year

    OpenAIRE

    Dal, Tuba

    2015-01-01

    Objectives: The aim of this study was to investigate Entamoeba histolytica in the stool samples that have been sent to microbiology laboratory by ELISA method. Materials and methods: This study was performed on 800 stool specimens belonging to different age groups and different patients sent to Microbiology Laboratory of a State Hospital between January 2009 and December 2009. Results: In this study Entamoeba histolytica/dispar cysts and/or trophozoites were observed in 31 (3.9%) out ...

  11. Prevalence of antibodies against Entamoeba histolytica in Mexico measured by ELISA

    OpenAIRE

    González, C.R.; Isibasi, A; Ortiz-Navarrete, V.; Paniagua, J.; García, J. A.; Ramirez, A.; Salvatierra, B.; Tapia, R.; Sepúlveda, J; Gutiérrez, G.; Kumate, J.

    1995-01-01

    The prevalence of antibodies against Entamoeba histolytica was studied in the Mexican population using an immunoenzyme assay in solid phase (ELISA) and semiautomatic equipment. The antigen was a mixture of membrane proteins obtained by Triton X-100 extraction from an axenic culture of Entamoeba histolytica HM1-IMSS. The method was standardized by comparing serum samples from amoebic liver abscess patients with healthy volunteers. From the 60538 samples supplied by the National Seroepidemiolog...

  12. Prevalence of antibodies against Entamoeba histolytica in Mexico measured by ELISA

    OpenAIRE

    González, C. R.; Isibasi, A.; Ortiz-Navarrete, V.; Paniagua, J; García, J. A.; Ramirez, A.; Salvatierra, B.; Tapia, R.; J. Sepúlveda; Gutiérrez, G.; Kumate, J

    1995-01-01

    The prevalence of antibodies against Entamoeba histolytica was studied in the Mexican population using an immunoenzyme assay in solid phase (ELISA) and semiautomatic equipment. The antigen was a mixture of membrane proteins obtained by Triton X-100 extraction from an axenic culture of Entamoeba histolytica HM1-IMSS. The method was standardized by comparing serum samples from amoebic liver abscess patients with healthy volunteers. From the 60538 samples supplied by the National Seroepidemiolog...

  13. Heritability of brain activity related to response inhibition: A longitudinal genetic study in adolescent twins.

    Science.gov (United States)

    Anokhin, Andrey P; Golosheykin, Simon; Grant, Julia D; Heath, Andrew C

    2017-05-01

    The ability to inhibit prepotent but context- or goal-inappropriate responses is essential for adaptive self-regulation of behavior. Deficits in response inhibition, a key component of impulsivity, have been implicated as a core dysfunction in a range of neuropsychiatric disorders such as ADHD and addictions. Identification of genetically transmitted variation in the neural underpinnings of response inhibition can help to elucidate etiological pathways to these disorders and establish the links between genes, brain, and behavior. However, little is known about genetic influences on the neural mechanisms of response inhibition during adolescence, a developmental period characterized by weak self-regulation of behavior. Here we investigated heritability of ERPs elicited in a Go/No-Go task in a large sample of adolescent twins assessed longitudinally at ages 12, 14, and 16. Genetic analyses showed significant heritability of inhibition-related frontal N2 and P3 components at all three ages, with 50 to 60% of inter-individual variability being attributable to genetic factors. These genetic influences included both common genetic factors active at different ages and novel genetic influences emerging during development. Finally, individual differences in the rate of developmental changes from age 12 to age 16 were significantly influenced by genetic factors. In conclusion, the present study provides the first evidence for genetic influences on neural correlates of response inhibition during adolescence and suggests that ERPs elicited in the Go/No-Go task can serve as intermediate neurophysiological phenotypes (endophenotypes) for the study of disinhibition and impulse control disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Pathogenic and Nonpathogenic Strains of Entamoeba histolytica can be Differentiated by Monoclonal Antibodies to the Galactose-Specific Adherence Lectin

    Science.gov (United States)

    1991-04-01

    AD- A235 913 DEVELOPMENT Ei ENGINEERING CENTER CRDEC-TR-268 PATHOGENIC AND NONPATHOGENIC STRAINS OF ENTAMOEBA HISTOLYTICA CAN BE DIFFERENTIATED BY...Pathogenic and Nonpathogenic Strains of Entamoeba Histolytica can be Differentiated by Monoclonal PR-IFJlX2XXRPEW Antibodies to the Galactose-Specific...galactose lectin produced by Entamoeba histolytica provide the basis for development of a model system for the environmental detection of adherence and

  15. [Investigation of the relationship between oral and dental health and presence of Entamoeba gingivalis and Trichomonas tenax].

    Science.gov (United States)

    Özçelık, Semra; Gedık, Tuğçe; Gedık, Rüştü; Malatyali, Erdoğan

    2010-01-01

    Entamoeba gingivalis and Trichomonas tenax can cause gingivitis and scale. In this study, the prevalence of E. gingivalis and T. tenax were investigated among patients who were admitted to the Cumhuriyet University, Faculty of Dentistry. Two scraping samples were taken from 220 patients (ages varying from 12 to 75 years) and a questionnaire including fifteen parameters was applied to all patients. The samples were diluted in Physiological Saline and examined immediately by Tech Lab Entamoeba Kit and Robinson Medium. Oral protozoa were detected in 58 (26.4%) of 220 scraping samples. In 48 (21.8%) of the positive 58 specimens, E. gingivalis was detected alone whereas T. tenax was present in only two (1%) specimens. In 8 (3.6%) specimens, E. gingivalis and T. tenax were identified together. Gender, age groups, dental caries and the number, shape disorders, systemic diseases, tooth pain, joint problems and wisdom teeth were not found to be significant with the presence of oral protozoa. However, gum problems, presence of tartar, smoking habits, brushing habits and control habits were found to be statistically significantly related with the presence of oral protozoa. In the present study, E. gingivalis and T. tenax were found to be common. These parasites, with additional parameters, may lead to gingivitis and scale.

  16. Establishment of a continuous culture system for Entamoeba muris and analysis of the small subunit rRNA gene

    Directory of Open Access Journals (Sweden)

    Kobayashi S.

    2009-06-01

    Full Text Available We established a culture system for Entamoeba muris (MG-EM-01 strain isolated from a Mongolian gerbil using a modified Balamuth’s egg yolk infusion medium supplemented with 4% adult bovine serum and Bacteroides fragilis cocultured with Escherichia coli. Further, encystation was observed in the culture medium. The morphological characteristics of E. muris are similar to those of Entamoeba coli (E. coli; moreover, the malic isoenzyme electrophoretic band, which shows species-specific electrophoretic mobility, of E. muris had almost the same mobility as that observed with the malic isoenzyme electrophorectic band of E. coli (UZG-EC-01 strain isolated from a gorilla. We determined the small subunit rRNA (SSU-rRNA gene sequence of the MG-EM-01 strain, and this sequence was observed to show 82.7% homology with that of the UZG-EC-01 strain. Further, the resultant phylogenetic tree for molecular taxonomy based on the SSU-rRNA genes of the 21 strains of the intestinal parasitic amoeba species indicated that the MG-EM-01 strain was most closely related to E. coli.

  17. A Duty To Warn Relatives in Clinical Genetics: Arguably 'Fair just and reasonable' in English Law?

    Science.gov (United States)

    Mitchell, C; Ploem, M C; Hennekam, R C M; Kaye, J

    2016-07-01

    The use of 'next-generation' genetic sequencing technology that allows the sequencing of large parts, or even the entirety, of a patient's genome is advancing rapidly in the UK and around the world. This is set to greatly increase the level of health information that will be of relevance to relatives and the latest medical guidance advises that there is a professional duty to consider warning a patient's relatives of a serious genetic risk in limited circumstances. However, the High Court in ABC v St George's Healthcare NHS Trust [2015] EWHC 1394 (QB), recently found that a legal duty on the part of doctors to warn a patient's daughter of a genetic risk of Huntington's Disease without the patient's consent, was not even 'reasonably arguable' and would not be 'fair, just and reasonable'. This article considers the courts' approach to a duty of care towards 'third parties' in this context and concludes that some form of a duty of care to genetic relatives in clinical genetics is at very least arguably 'fair, just and reasonable'.

  18. Between personal and relational privacy: understanding the work of informed consent in cancer genetics in Brazil.

    Science.gov (United States)

    Goldim, José Roberto; Gibbon, Sahra

    2015-07-01

    Drawing from perspectives of both bioethics and anthropology, this article explores how the boundaries between personal and relational privacy are negotiated by patients and practitioners in the context of an emerging domain of cancer genetics in Brazil. It reflects on the place of informed consent in the history of bioethics in North America in contrast to the development of bioethics in Brazil and the particular social cultural context in which consent is sought in Brazilian public health care. Making use of empirical research with families and individuals receiving genetic counselling related to increased genetic risk for cancer, in genetic clinics in southern Brazil, it examines how informed consent is linked to the necessary movement between personal and relational privacy. The paper illustrates the value of a particular tool known as a 'sociogram' to examine the complex interpersonal dynamics that arise in negotiating informed consent at the interface between the family and the individual in Brazil. The paper, therefore, points to the scope of further interdisciplinary exchanges between anthropology and bioethics, confronting the new challenges that arise in the context of medical genetics in developing country.

  19. Genetic evidence for causal relationships between maternal obesity-related traits and birth weight

    Science.gov (United States)

    Tyrrell, Jessica; Richmond, Rebecca C.; Palmer, Tom M.; Feenstra, Bjarke; Rangarajan, Janani; Metrustry, Sarah; Cavadino, Alana; Paternoster, Lavinia; Armstrong, Loren L.; De Silva, N. Maneka G.; Wood, Andrew R.; Horikoshi, Momoko; Geller, Frank; Myhre, Ronny; Bradfield, Jonathan P.; Kreiner-Møller, Eskil; Huikari, Ville; Painter, Jodie N.; Hottenga, Jouke-Jan; Allard, Catherine; Berry, Diane J.; Bouchard, Luigi; Das, Shikta; Evans, David M.; Hakonarson, Hakon; Hayes, M. Geoffrey; Heikkinen, Jani; Hofman, Albert; Knight, Bridget; Lind, Penelope A.; McCarthy, Mark I.; McMahon, George; Medland, Sarah E.; Melbye, Mads; Morris, Andrew P.; Nodzenski, Michael; Reichetzeder, Christoph; Ring, Susan M.; Sebert, Sylvain; Sengpiel, Verena; Sørensen, Thorkild I.A.; Willemsen, Gonneke; de Geus, Eco J. C.; Martin, Nicholas G.; Spector, Tim D.; Power, Christine; Järvelin, Marjo-Riitta; Bisgaard, Hans; Grant, Struan F.A.; Nohr, Ellen A.; Jaddoe, Vincent W.; Jacobsson, Bo; Murray, Jeffrey C.; Hocher, Berthold; Hattersley, Andrew T.; Scholtens, Denise M.; Smith, George Davey; Hivert, Marie-France; Felix, Janine F.; Hyppönen, Elina; Lowe, William L.; Frayling, Timothy M.; Lawlor, Debbie A.; Freathy, Rachel M.

    2016-01-01

    Structured abstract Importance Neonates born to overweight/obese women are larger and at higher risk of birth complications. Many maternal obesity-related traits are observationally associated with birth weight, but the causal nature of these associations is uncertain. Objective To test for genetic evidence of causal associations of maternal body mass index (BMI) and related traits with birth weight. Design, Setting and Participants We used Mendelian randomization to test whether maternal BMI and obesity-related traits are causally related to offspring birth weight. Mendelian randomization makes use of the fact that genotypes are randomly determined at conception and are thus not confounded by non-genetic factors. Data were analysed on 30,487 women from 18 studies. Participants were of European ancestry from population- or community-based studies located in Europe, North America or Australia and participating in the Early Growth Genetics (EGG) Consortium. Live, term, singleton offspring born between 1929 and 2013 were included. We tested associations between a genetic score of 30 BMI-associated single nucleotide polymorphisms (SNPs) and (i) maternal BMI and (ii) birth weight, to estimate the causal relationship between BMI and birth weight. Analyses were repeated for other obesity-related traits. Exposures Genetic scores for BMI, fasting glucose level, type 2 diabetes, systolic blood pressure (SBP), triglyceride level, HDL-cholesterol level, vitamin D status and adiponectin level. Main Outcome(s) and Measure(s) Offspring birth weight measured by trained study personnel (n=2 studies), from medical records (n= 10 studies) or from maternal report (n=6 studies). Results Among the 30,487 newborns the mean birth weight in the various cohorts ranged from 3325 g to 3679 g. The genetic score for BMI was associated with a 2g (95%CI: 0, 3g) higher offspring birth weight per maternal BMI-raising allele (P=0.008). The maternal genetic scores for fasting glucose and SBP were

  20. The future for vaccine development against Entamoeba histolytica.

    Science.gov (United States)

    Quach, Jeanie; St-Pierre, Joëlle; Chadee, Kris

    2014-01-01

    Entamoeba histolytica is the causative agent of amebiasis, one of the top three parasitic causes of mortality worldwide. In the majority of infected individuals, E. histolytica asymptomatically colonizes the large intestine, while in others, the parasite breaches the mucosal epithelial barrier to cause amebic colitis and can disseminate to soft organs to cause abscesses. Vaccinations using native and recombinant forms of the parasite Gal-lectin have been successful in protecting animals against intestinal amebiasis and amebic liver abscess. Protection against amebic liver abscesses has also been reported by targeting other E. histolytica components including the serine-rich protein and the 29-kDa-reductase antigen. To date, vaccines against the Gal-lectin hold the most promise but clinical trials will be required to validate its efficacy in humans. Here, we review the current strategies and future perspectives involved in the development of a vaccine against E. histolytica.

  1. Taking a bite: Amoebic trogocytosis in Entamoeba histolytica and beyond.

    Science.gov (United States)

    Ralston, Katherine S

    2015-12-01

    Entamoeba histolytica is a diarrheal pathogen with the ability to cause profound host tissue damage. This organism possesses contact-dependent cell killing activity, which is likely to be a major contributor to tissue damage. E. histolytica trophozoites were recently shown to ingest fragments of living human cells. It was demonstrated that this process, termed amoebic trogocytosis, contributes to cell killing. Recent advances in ex vivo and 3-D cell culture approaches have shed light on mechanisms for tissue destruction by E. histolytica, allowing amoebic trogocytosis to be placed in the context of additional host and pathogen mediators of tissue damage. In addition to its relevance to pathogenesis of amoebiasis, an appreciation is emerging that intercellular nibbling occurs in many organisms, from protozoa to mammals.

  2. The future for vaccine development against Entamoeba histolytica

    Science.gov (United States)

    Quach, Jeanie; St-Pierre, Joëlle; Chadee, Kris

    2014-01-01

    Entamoeba histolytica is the causative agent of amebiasis, one of the top three parasitic causes of mortality worldwide. In the majority of infected individuals, E. histolytica asymptomatically colonizes the large intestine, while in others, the parasite breaches the mucosal epithelial barrier to cause amebic colitis and can disseminate to soft organs to cause abscesses. Vaccinations using native and recombinant forms of the parasite Gal-lectin have been successful in protecting animals against intestinal amebiasis and amebic liver abscess. Protection against amebic liver abscesses has also been reported by targeting other E. histolytica components including the serine-rich protein and the 29-kDa-reductase antigen. To date, vaccines against the Gal-lectin hold the most promise but clinical trials will be required to validate its efficacy in humans. Here, we review the current strategies and future perspectives involved in the development of a vaccine against E. histolytica. PMID:24504133

  3. Detection of Entamoeba histolytica by Recombinase Polymerase Amplification

    Science.gov (United States)

    Nair, Gayatri; Rebolledo, Mauricio; White, A. Clinton; Crannell, Zachary; Richards-Kortum, R. Rebecca; Pinilla, A. Elizabeth; Ramírez, Juan David; López, M. Consuelo; Castellanos-Gonzalez, Alejandro

    2015-01-01

    Amebiasis is an important cause of diarrheal disease worldwide and has been associated with childhood malnutrition. Traditional microscopy approaches are neither sensitive nor specific for Entamoeba histolytica. Antigen assays are more specific, but many cases are missed unless tested by molecular methods. Although polymerase chain reaction (PCR) is effective, the need for sophisticated, expensive equipment, infrastructure, and trained personnel limits its usefulness, especially in the resource-limited, endemic areas. Here, we report development of a recombinase polymerase amplification (RPA) method to detect E. histolytica specifically. Using visual detection by lateral flow (LF), the test was highly sensitive and specific and could be performed without additional equipment. The availability of this inexpensive, sensitive, and field-applicable diagnostic test could facilitate rapid diagnosis and treatment of amebiasis in endemic regions. PMID:26123960

  4. Detection of Entamoeba histolytica by Recombinase Polymerase Amplification.

    Science.gov (United States)

    Nair, Gayatri; Rebolledo, Mauricio; White, A Clinton; Crannell, Zachary; Richards-Kortum, R Rebecca; Pinilla, A Elizabeth; Ramírez, Juan David; López, M Consuelo; Castellanos-Gonzalez, Alejandro

    2015-09-01

    Amebiasis is an important cause of diarrheal disease worldwide and has been associated with childhood malnutrition. Traditional microscopy approaches are neither sensitive nor specific for Entamoeba histolytica. Antigen assays are more specific, but many cases are missed unless tested by molecular methods. Although polymerase chain reaction (PCR) is effective, the need for sophisticated, expensive equipment, infrastructure, and trained personnel limits its usefulness, especially in the resource-limited, endemic areas. Here, we report development of a recombinase polymerase amplification (RPA) method to detect E. histolytica specifically. Using visual detection by lateral flow (LF), the test was highly sensitive and specific and could be performed without additional equipment. The availability of this inexpensive, sensitive, and field-applicable diagnostic test could facilitate rapid diagnosis and treatment of amebiasis in endemic regions.

  5. Molecular epidemiology of amoebiasis in Malaysia: highlighting the different risk factors of Entamoeba histolytica and Entamoeba dispar infections among Orang Asli communities.

    Science.gov (United States)

    Anuar, Tengku Shahrul; Al-Mekhlafi, Hesham M; Abdul Ghani, Mohamed Kamel; Abu Bakar, Edariah; Azreen, Siti Nor; Salleh, Fatmah Md; Ghazali, Nuraffini; Bernadus, Mekadina; Moktar, Norhayati

    2012-12-01

    Currently, species-specific information on Entamoeba infections is unavailable in Malaysia and is restricted worldwide due to the re-description of pathogenic Entamoeba histolytica and non-pathogenic Entamoeba dispar and Entamoeba moshkovskii. Therefore, this cross-sectional study was conducted to provide the first known documented data on the true prevalence of these three species in western Malaysia using a molecular method. Another aim of this study was to determine the association of potential risk factors associated with each Entamoeba sp. A total of 500 stool samples from three Orang Asli tribes were randomly collected. The overall prevalence of E. histolytica, E. dispar and E. moshkovskii determined by microscopy was 18.6% (93/500). Molecular analysis revealed that while most Entamoeba-positive individuals were infected with E. dispar (13.4%), followed by E. histolytica (3.2%) and E. moshkovskii (1.0%), the present findings show low prevalence rates of mixed infections with E. histolytica and E. dispar (2%), E. dispar and E. moshkovskii (1.2%) and association infections of E. histolytica, E. dispar and E. moshkovskii (0.4%). Logistical regression analysis indicates that the dynamics of the transmission of the three Entamoeba spp. was different. Of six statistically significant variables observed in the univariate analysis, three were retained as significant risk factors for E. histolytica infection in the logistical regression model. These factors were (i) not washing hands after playing with soil or gardening (Odds ratio (OR)=4.7; 95% confidence level (CI)=1.38, 16.14; P=0.013), (ii) indiscriminate defecation in the river or bush (OR=5.7; 95% CI=1.46, 21.95; P=0.012) and (iii) close contact with domestic animals (OR=5.4; 95% CI=1.36, 2.51; P=0.017). However, subjects with family members who were infected with E. histolytica/E. dispar/E. moshkovskii (OR=3.8; 95 CI=2.11, 6.86; Phistolytica infection. The present study provides new insight into the

  6. C9orf72-related disorders: expanding the clinical and genetic spectrum of neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    Paulo Victor Sgobbi de Souza

    2015-03-01

    Full Text Available Neurodegenerative diseases represent a heterogeneous group of neurological conditions primarily involving dementia, motor neuron disease and movement disorders. They are mostly related to different pathophysiological processes, notably in family forms in which the clinical and genetic heterogeneity are lush. In the last decade, much knowledge has been acumulated about the genetics of neurodegenerative diseases, making it essential in cases of motor neuron disease and frontotemporal dementia the repeat expansions of C9orf72 gene. This review analyzes the main clinical, radiological and genetic aspects of the phenotypes related to the hexanucleotide repeat expansions (GGGGCC of C9orf72 gene. Future studies will aim to further characterize the neuropsychological, imaging and pathological aspects of the extra-motor features of motor neuron disease, and will help to provide a new classification system that is both clinically and biologically relevant.

  7. Interactions between meat intake and genetic variation in relation to colorectal cancer

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Vogel, Ulla

    2015-01-01

    Meat intake is associated with the risk of colorectal cancer. The objective of this systematic review was to evaluate interactions between meat intake and genetic variation in order to identify biological pathways involved in meat carcinogenesis. We performed a literature search of Pub...... a polymorphism in XPC and meat was found in one prospective and one case-control study; however, the directions of the risk estimates were opposite. Thus, none of the findings were replicated. The results from this systematic review suggest that genetic variation in the inflammatory response and DNA repair...... pathway is involved in meat-related colorectal carcinogenesis, whereas no support for the involvement of heme and iron from meat or cooking mutagens was found. Further studies assessing interactions between meat intake and genetic variation in relation to CRC in large well-characterised prospective...

  8. Stress-related hormones and genetic diversity in sea otters (Enhydra lutris)

    Science.gov (United States)

    Larson, S.; Monson, D.; Ballachey, B.; Jameson, R.; Wasser, S.K.

    2009-01-01

    Sea otters (Enhydra lutris) once ranged throughout the coastal regions of the north Pacific, but were extirpated throughout their range during the fur trade of the 18th and 19th centuries, leaving only small, widely scattered, remnant populations. All extant sea otter populations are believed to have experienced a population bottleneck and thus have lost genetic variation. Populations that undergo severe population reduction and associated inbreeding may suffer from a general reduction in fitness termed inbreeding depression. Inbreeding depression may result in decreased testosterone levels in males, and reduced ability to respond to stressful stimuli associated with an increase in the stress-related adrenal glucocorticoid hormones, cortisol and corticosterone. We investigated correlations of testosterone, cortisol, and corticosterone with genetic diversity in sea otters from five populations. We found a significant negative correlation between genetic diversity and both mean population-level (r2 = 0.27, P < 0.001) and individual-level (r2 = 0.54, P < 0.001) corticosterone values, as well as a negative correlation between genetic diversity and cortisol at the individual level (r2 = 0.17, P = 0.04). No relationship was found between genetic diversity and testosterone (P = 0.57). The strength of the correlations, especially with corticosterone, suggests potential negative consequences for overall population health, particularly for populations with the lowest genetic diversity. ?? 2009 by the Society for Marine Mammalogy.

  9. Genetic control of the alternative pathway of complement in humans and age-related macular degeneration.

    Science.gov (United States)

    Hecker, Laura A; Edwards, Albert O; Ryu, Euijung; Tosakulwong, Nirubol; Baratz, Keith H; Brown, William L; Charbel Issa, Peter; Scholl, Hendrik P; Pollok-Kopp, Beatrix; Schmid-Kubista, Katharina E; Bailey, Kent R; Oppermann, Martin

    2010-01-01

    Activation of the alternative pathway of complement is implicated in common neurodegenerative diseases including age-related macular degeneration (AMD). We explored the impact of common variation in genes encoding proteins of the alternative pathway on complement activation in human blood and in AMD. Genetic variation across the genes encoding complement factor H (CFH), factor B (CFB) and component 3 (C3) was determined. The influence of common haplotypes defining transcriptional and translational units on complement activation in blood was determined in a quantitative genomic association study. Individual haplotypes in CFH and CFB were associated with distinct and novel effects on plasma levels of precursors, regulators and activation products of the alternative pathway of complement in human blood. Further, genetic variation in CFH thought to influence cell surface regulation of complement did not alter plasma complement levels in human blood. Plasma markers of chronic activation (split-products Ba and C3d) and an activating enzyme (factor D) were elevated in AMD subjects. Most of the elevation in AMD was accounted for by the genetic variation controlling complement activation in human blood. Activation of the alternative pathway of complement in blood is under genetic control and increases with age. The genetic variation associated with increased activation of complement in human blood also increased the risk of AMD. Our data are consistent with a disease model in which genetic variation in the complement system increases the risk of AMD by a combination of systemic complement activation and abnormal regulation of complement activation in local tissues.

  10. Identification of trends in scientific publications related to genetic polymorphisms in gestational diabetes mellitus.

    Science.gov (United States)

    Gomes, J S; Minasi, L B; da Cruz, A D; Rodrigues, F M

    2016-05-09

    Gestational diabetes is a genetic multifactorial systemic disease that has been extensively studied. Consequently, there is a large volume of scientific literature pertaining to genes associated with gestational diabetes. The aim of this study was to characterize the main trends in scientific publications focusing on the associations between genetic polymorphisms and gestational diabetes mellitus (GDM). The related articles were extracted from Scopus using the key words "genetic polymorphism" and "gestational diabetes mellitus"; the collected data focused on various fields (medical, biochemical, etc.) and included papers published within December 2013. One hundred and eighty-three relevant articles published between 1987 and 2013 were identified; we observed a significantly increasing trend in the number of publications pertaining to GDM. A majority of the articles focused on the medical (59.9%), biochemical, and genetics and molecular biological (29.6%) aspects of the disease. The genes coding for transcription factor 7-like 2 and glucokinase (TCF7L2, 29% and GCK, 28%) were predominantly studied and reported. This study helped quantify the growth in research pertaining to GDM; researchers from the USA have published a majority of the publications related to GDM. Several candidate genes have been linked to diabetes; however, the specific gene locus responsible for GDM has not yet been identified. The results of this study could help determine the orientation of future research on genetic factors associated with GDM.

  11. Genetics Home Reference: RRM2B-related mitochondrial DNA depletion syndrome, encephalomyopathic form with renal ...

    Science.gov (United States)

    ... Munnich A, Rötig A. Mutation of RRM2B, encoding p53-controlled ribonucleotide reductase (p53R2), causes severe mitochondrial DNA depletion. Nat Genet. 2007 Jun;39(6):776-80. Epub 2007 May 7. Citation on PubMed GeneReview: RRM2B-Related Mitochondrial Disease Pontarin G, Ferraro P, Bee L, Reichard P, ...

  12. Spina bifida and genetic factors related to myo-inositol, glucose, and zinc.

    NARCIS (Netherlands)

    Groenen, P.; Klootwijk, E.D.; Schijvenaars, M.M.V.A.P.; Straatman, H.M.P.M.; Mariman, E.C.M.; Franke, B.; Steegers-Theunissen, R.P.M.

    2004-01-01

    BACKGROUND: Myo-inositol, glucose and zinc and related genetic factors are suggested to be implicated in the etiology of spina bifida. We investigated the biochemical concentrations of these nutrients and polymorphisms in the myo-inositol transporter SLC5A11, myo-inositol synthase ISYNA1, and zinc

  13. Genetic relation of adamantanes from extracts and semicoking tars of lignites with the initial biological material

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V.V.; Shvykin, A.Y.; Proskuryakov, V.A.; Podshibyakin, S.I. [Lev Tolstoi State Pedagogical University, Tula (Russian Federation)

    1999-11-01

    A genetic relation was revealed of adamantanes from extracts and semicoking tars of lignites with the relic terpenoid and steroid compounds. Probable pathways are suggested for transformation of the initial natural structures into adamantanes. The qualitative and quantitative compositions of adamantanes from crude oil and coal are compared.

  14. Detecting shared pathogenesis from the shared genetics of immune-related diseases

    NARCIS (Netherlands)

    Zhernakova, Alexandra; van Diemen, Cleo C.; Wijmenga, Cisca

    Recent genetic studies have revealed shared immunological mechanisms in several immune-related disorders that further our understanding of the development and concomitance of these diseases. Our Review focuses on these shared aspects, using the novel findings of recently performed genome-wide

  15. Genetic evidence for causal relationships between maternal obesity-related traits and birth weight

    NARCIS (Netherlands)

    A.W.R. Tyrrell; R.C. Richmond (Rebecca C.); T.M. Palmer (Tom); B. Feenstra (Bjarke); J. Rangarajan (Janani); S. Metrustry (Sarah); A. Cavadino (Alana); L. Paternoster (Lavinia); L.L. Armstrong (Loren L.); N.M.G. De Silva (N. Maneka G.); A.R. Wood (Andrew); M. Horikoshi (Momoko); F. Geller (Frank); R. Myhre (Ronny); J.P. Bradfield (Jonathan); E. Kreiner-Møller (Eskil); I. Huikari (Ille); J.N. Painter (Jodie N.); J.J. Hottenga (Jouke Jan); C. Allard (Catherine); D. Berry (Diane); L. Bouchard (Luigi); S. Das; D.M. Evans (David); H. Hakonarson (Hakon); M.G. Hayes (M. Geoffrey); J. Heikkinen (Jani); A. Hofman (Albert); B.A. Knight (Bridget); P.A. Lind (Penelope); M.I. McCarthy (Mark); G. Mcmahon (George); S.E. Medland (Sarah Elizabeth); M. Melbye (Mads); A.P. Morris (Andrew); M. Nodzenski (Michael); C. Reichetzeder (Christoph); S.M. Ring (Susan); S. Sebert (Sylvain); V. Sengpiel (Verena); T.I.A. Sørensen (Thorkild); G.A.H.M. Willemsen (Gonneke); E.J.C. de Geus (Eco); N.G. Martin (Nicholas); T.D. Spector (Timothy); C. Power (Christine); M.-R. Jarvelin (Marjo-Riitta); H. Bisgaard (Hans); S.F. Grant; C. Nohr (Christian); V.W.V. Jaddoe (Vincent); B. Jacobsson (Bo); J.C. Murray (Jeffrey C.); B. Hocher (Berthold); A.T. Hattersley (Andrew); D.M. Scholtens (Denise M.); G.D. Smith; M.-F. Hivert (Marie-France); J.F. Felix (Janine); E. Hypponen (Elina); W.L. Lowe Jr. (William); T.M. Frayling (Timothy); D.A. Lawlor (Debbie); R.M. Freathy (Rachel)

    2016-01-01

    textabstractIMPORTANCE Neonates born to overweight or obese women are larger and at higher risk of birth complications. Many maternal obesity-related traits are observationally associated with birth weight, but the causal nature of these associations is uncertain. OBJECTIVE To test for genetic evide

  16. Genetic structure of Polytrichum formosum in relation to the breeding system as revealed by microsatellites

    NARCIS (Netherlands)

    Van der Velde, M; Van de Zande, L; Bijlsma, R

    2001-01-01

    Microsatellite variation was determined for three Danish and three Dutch populations of the haploid moss species Polytrichum formosum to gain insight into the relative importance of sexual vs. asexual reproduction for the amount and structure of genetic variation. In general, low levels of microsate

  17. Genetics

    DEFF Research Database (Denmark)

    Christensen, Kaare; McGue, Matt

    2016-01-01

    The sequenced genomes of individuals aged ≥80 years, who were highly educated, self-referred volunteers and with no self-reported chronic diseases were compared to young controls. In these data, healthy ageing is a distinct phenotype from exceptional longevity and genetic factors that protect...

  18. An evaluation of mitochondrial tRNA gene evolution and its relation to the genetic code.

    Science.gov (United States)

    Cedergren, R J

    1982-04-01

    Extensive sequence data on mitochondrial (mt) tRNAs give for the first time an opportunity to evaluate tRNA gene evolution in this organelle. Deductions from these gene structures relate to the evolution of tRNA genes in other cellular systems and to the origin of the genetic code. Mt tRNAs, in contrast to the prokaryotic nature of chloroplastic tRNA structure, can not at the present time be definitely related to either prokaryotic or eukaryotic tRNAs, probably because of a higher mutation rate in mitochondria. Fungal mt tRNAs having the same anticodon and function are generally similar enough to be considered homologous. Comparisons af all mt tRNA sequences contained in the same mitochondrion indicate that some tRNAs originated by duplication of a prototypic gene which, after divergence, led to tRNAs having different amino acid specificities. The deviant mt genetic code, although admittedly permitting a simpler decoding mechanism, is not useful in determining whether the origin of mitochondria had preceded or was derived from prokaryotes or eukaryotes, since the genetic code is variable even among mitochondria. Variants of the mt genetic code lead to speculation on the nature of the primordial code and its relation to the present "universal" code.

  19. Age-related decline in brain resources modulates genetic effects on cognitive functioning

    Directory of Open Access Journals (Sweden)

    Ulman Lindenberger

    2008-12-01

    Full Text Available Individual differences in cognitive performance increase from early to late adulthood, likely reflecting influences of a multitude of factors. We hypothesize that losses in neurochemical and anatomical brain resources in normal aging modulate the effects of common genetic variations on cognitive functioning. Our hypothesis is based on the assumption that the function relating brain resources to cognition is nonlinear, so that genetic differences exert increasingly large effects on cognition as resources recede from high to medium levels in the course of aging.Direct empirical support for this hypothesis comes from a study by Nagel et al. (2008, who reported that the effects of the Catechol-O-Methyltransferase (COMT gene on cognitive performance are magnified in old age and interacted with the Brain-Derived Neurotrophic Factor (BDNF gene. We conclude that common genetic polymorphisms contribute to the increasing heterogeneity of cognitive functioning in old age. Extensions of the hypothesis to other polymorphisms are discussed.

  20. Age-Related Decline in Brain Resources Modulates Genetic Effects on Cognitive Functioning

    Science.gov (United States)

    Lindenberger, Ulman; Nagel, Irene E.; Chicherio, Christian; Li, Shu-Chen; Heekeren, Hauke R.; Bäckman, Lars

    2008-01-01

    Individual differences in cognitive performance increase from early to late adulthood, likely reflecting influences of a multitude of factors. We hypothesize that losses in neurochemical and anatomical brain resources in normal aging modulate the effects of common genetic variations on cognitive functioning. Our hypothesis is based on the assumption that the function relating brain resources to cognition is nonlinear, so that genetic differences exert increasingly large effects on cognition as resources recede from high to medium levels in the course of aging. Direct empirical support for this hypothesis comes from a study by Nagel et al. (2008), who reported that the effects of the Catechol-O-Methyltransferase (COMT) gene on cognitive performance are magnified in old age and interacted with the Brain-Derived Neurotrophic Factor (BDNF) gene. We conclude that common genetic polymorphisms contribute to the increasing heterogeneity of cognitive functioning in old age. Extensions of the hypothesis to other polymorphisms are discussed. (150 of 150 words) PMID:19225597

  1. Introgression of transgenic crop alleles: Its evolutionary impacts on conserving genetic diversity of crop wild relatives

    Institute of Scientific and Technical Information of China (English)

    Bao-Rong LU

    2013-01-01

    Effective conservation of crop wild relative (CWR) species is essential for the sustainable use and genetic improvement of crop varieties,which offers greater opportunities for world food security,particularly in modem agroecosystems where CWR diversity is under severe threat.Factors such as habitat fragmentation,human disturbances,global climate change,and invasion of harmful alien species have been identified to be responsible for losses and threats to CWR diversity.However,a neglected factor,gene introgression from domesticated species through repeated outcrossing,may have a significant impact on CWR diversity.Introgression can influence genetic diversity and evolutionary processes of CWR populations through effects such as demographic swarming,genetic assimilation,and selective sweep.When largely enhancing or reducing fitness of wild plants,the introgression of crop genes will impose more significant genetic and evolutionary impacts on CWR populations,leading to undesired consequences for conserved CWR populations and species.This situation is particularly true when genetically engineered (GE) crops are deployed for commercial cultivation.It is argued that a GE crop usually contains transgenes with strong natural selection advantages,and such transgenes introgressed into CWR populations may have strong impacts on their genetic diversity and evolutionary processes,threatening their conservation.This article reviews the challenge of crop-wild gene flow,and particularly transgene introgression from GE crops,for the in situ conservation of wild relative species.The design of effective management strategies for conserving CWR species under the scenario of extensive cultivation of GE crops is also discussed.

  2. Gene expression profiling in Entamoeba histolytica identifies key components in iron uptake and metabolism.

    Directory of Open Access Journals (Sweden)

    Nora Adriana Hernández-Cuevas

    Full Text Available Entamoeba histolytica is an ameboid parasite that causes colonic dysentery and liver abscesses in humans. The parasite encounters dramatic changes in iron concentration during its invasion of the host, with relatively low levels in the intestinal lumen and then relatively high levels in the blood and liver. The liver notably contains sources of iron; therefore, the parasite's ability to use these sources might be relevant to its survival in the liver and thus the pathogenesis of liver abscesses. The objective of the present study was to identify factors involved in iron uptake, use and storage in E. histolytica. We compared the respective transcriptomes of E. histolytica trophozoites grown in normal medium (containing around 169 µM iron, low-iron medium (around 123 µM iron, iron-deficient medium (around 91 µM iron, and iron-deficient medium replenished with hemoglobin. The differentially expressed genes included those coding for the ATP-binding cassette transporters and major facilitator transporters (which share homology with bacterial siderophores and heme transporters and genes involved in heme biosynthesis and degradation. Iron deficiency was associated with increased transcription of genes encoding a subset of cell signaling molecules, some of which have previously been linked to adaptation to the intestinal environment and virulence. The present study is the first to have assessed the transcriptome of E. histolytica grown under various iron concentrations. Our results provide insights into the pathways involved in iron uptake and metabolism in this parasite.

  3. Gene expression profiling in Entamoeba histolytica identifies key components in iron uptake and metabolism.

    Science.gov (United States)

    Hernández-Cuevas, Nora Adriana; Weber, Christian; Hon, Chung-Chau; Guillen, Nancy

    2014-01-01

    Entamoeba histolytica is an ameboid parasite that causes colonic dysentery and liver abscesses in humans. The parasite encounters dramatic changes in iron concentration during its invasion of the host, with relatively low levels in the intestinal lumen and then relatively high levels in the blood and liver. The liver notably contains sources of iron; therefore, the parasite's ability to use these sources might be relevant to its survival in the liver and thus the pathogenesis of liver abscesses. The objective of the present study was to identify factors involved in iron uptake, use and storage in E. histolytica. We compared the respective transcriptomes of E. histolytica trophozoites grown in normal medium (containing around 169 µM iron), low-iron medium (around 123 µM iron), iron-deficient medium (around 91 µM iron), and iron-deficient medium replenished with hemoglobin. The differentially expressed genes included those coding for the ATP-binding cassette transporters and major facilitator transporters (which share homology with bacterial siderophores and heme transporters) and genes involved in heme biosynthesis and degradation. Iron deficiency was associated with increased transcription of genes encoding a subset of cell signaling molecules, some of which have previously been linked to adaptation to the intestinal environment and virulence. The present study is the first to have assessed the transcriptome of E. histolytica grown under various iron concentrations. Our results provide insights into the pathways involved in iron uptake and metabolism in this parasite.

  4. Polymorphonuclear neutrophil infiltration intensity as consequence of Entamoeba histolytica density in amebic colitis.

    Science.gov (United States)

    Dickson-Gonzalez, Sonia M; de Uribe, Marleny Lunar; Rodriguez-Morales, Alfonso J

    2009-04-01

    It has been suggested that the damage observed in invasive amebiasis is related to interactions between polymorphonuclear leukocytes (PMN) and Entamoeba histolytica trophozoites. We analyzed the relation between infiltrating inflammatory cell populations and E. histolytica density in intestinal amebic lesions. Biopsies obtained endoscopically from patients with amebic colitis were analyzed to describe their morphologic abnormalities. Cellular populations and E. histolytica trophozoites were measured quantitatively in order to assess the correlation between infiltrating inflammatory cell populations and parasite density. Amebic lesions were most often located in the colon (55%). The histopathologic diagnoses were colitis in 31%, erosive colitis in 26%, and ulcerated colitis in 24%. The predominant cellular populations found in the lesions were lymphocytes (59.8%) (3,672 +/- 2,413/mm(2)) followed by PMN (17%) (1,038 +/- 1,171 PMN/mm(2)) (p < 0.01). A higher density of PMN infiltration was observed in severe cases. Cellular populations predictive of the presence of E. histolytica trophozoites (p = 0.047) were PMN (p = 0.019) and lymphocytes (p = 0.033). The highest association was found between E. histolytica trophozoites and PMN (p = 0.0221). Neutrophils and lymphocytes, particularly the former, are associated significantly with the density of parasites. Our findings support the theory that PMN interaction with E. histolytica contributes to the pathogenesis of amebic intestinal lesions.

  5. Heterotrimeric G-protein signaling is critical to pathogenic processes in Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    Dustin E Bosch

    Full Text Available Heterotrimeric G-protein signaling pathways are vital components of physiology, and many are amenable to pharmacologic manipulation. Here, we identify functional heterotrimeric G-protein subunits in Entamoeba histolytica, the causative agent of amoebic colitis. The E. histolytica Gα subunit EhGα1 exhibits conventional nucleotide cycling properties and is seen to interact with EhGβγ dimers and a candidate effector, EhRGS-RhoGEF, in typical, nucleotide-state-selective fashions. In contrast, a crystal structure of EhGα1 highlights unique features and classification outside of conventional mammalian Gα subfamilies. E. histolytica trophozoites overexpressing wildtype EhGα1 in an inducible manner exhibit an enhanced ability to kill host cells that may be wholly or partially due to enhanced host cell attachment. EhGα1-overexpressing trophozoites also display enhanced transmigration across a Matrigel barrier, an effect that may result from altered baseline migration. Inducible expression of a dominant negative EhGα1 variant engenders the converse phenotypes. Transcriptomic studies reveal that modulation of pathogenesis-related trophozoite behaviors by perturbed heterotrimeric G-protein expression includes transcriptional regulation of virulence factors and altered trafficking of cysteine proteases. Collectively, our studies suggest that E. histolytica possesses a divergent heterotrimeric G-protein signaling axis that modulates key aspects of cellular processes related to the pathogenesis of this infectious organism.

  6. Heterotrimeric G-protein Signaling Is Critical to Pathogenic Processes in Entamoeba histolytica

    Science.gov (United States)

    Muller, Robin E.; Giguère, Patrick M.; Machius, Mischa; Willard, Francis S.; Temple, Brenda R. S.; Siderovski, David P.

    2012-01-01

    Heterotrimeric G-protein signaling pathways are vital components of physiology, and many are amenable to pharmacologic manipulation. Here, we identify functional heterotrimeric G-protein subunits in Entamoeba histolytica, the causative agent of amoebic colitis. The E. histolytica Gα subunit EhGα1 exhibits conventional nucleotide cycling properties and is seen to interact with EhGβγ dimers and a candidate effector, EhRGS-RhoGEF, in typical, nucleotide-state-selective fashions. In contrast, a crystal structure of EhGα1 highlights unique features and classification outside of conventional mammalian Gα subfamilies. E. histolytica trophozoites overexpressing wildtype EhGα1 in an inducible manner exhibit an enhanced ability to kill host cells that may be wholly or partially due to enhanced host cell attachment. EhGα1-overexpressing trophozoites also display enhanced transmigration across a Matrigel barrier, an effect that may result from altered baseline migration. Inducible expression of a dominant negative EhGα1 variant engenders the converse phenotypes. Transcriptomic studies reveal that modulation of pathogenesis-related trophozoite behaviors by perturbed heterotrimeric G-protein expression includes transcriptional regulation of virulence factors and altered trafficking of cysteine proteases. Collectively, our studies suggest that E. histolytica possesses a divergent heterotrimeric G-protein signaling axis that modulates key aspects of cellular processes related to the pathogenesis of this infectious organism. PMID:23166501

  7. Sequence Diversity in tRNA Gene Locus A-L among Iranian Isolates of Entamoeba Dispar

    Directory of Open Access Journals (Sweden)

    M Rostami-Nejad

    2012-02-01

    Full Text Available Background: A number of methods for detecting diversity in Entamoeba have been described over the years. In the present study the genetic polymorphism of noncoding locus A-L was ana­lyzed using PCR and sequencing in order to clarify the genotypic differences among E. dispar isolates.Methods: A total of 28 E. dispar from patients with gastrointestinal symptoms were determined and the genomic DNA was extracted directly from stool. For genotype analysis; Locus A-L was amplified by PCR and PCR products were sequenced .The sequences obtained were edited ma­nually and aligned using Gene Runner software.Results: With sequencing of PCR products a reliable genetic diversity in size, number and posi­tion of the repeat units were observed among the Iranian E. dispar isolates in locus A-L gene. Se­quences showed variation in length from 448bp to 507bp and seven distinct types were identified.Conclusion: The genetic diversity of loci like A-L shows them to be suitable for epidemiological studies such as the characterization of the routes of transmission of these parasites in Iran.

  8. Genetic basis of hybrid male sterility among three closely related species of Drosophila.

    Science.gov (United States)

    Mishra, Paras Kumar; Singh, B N

    2005-05-01

    The genetic basis of hybrid male sterility among three closely related species, Drosophila bipectinata, D. parabipectinata and D. malerkotliana has been investigated by using backcross analysis methods. The role of Y chromosome, major hybrid sterility (MHS) genes (genetic factors) and cytoplasm (non-genetic factor) have been studied in the hybrids of these three species. In the species pair, bipectinata--parabipectinata, Y chromosome introgression of parabipectinata in the genomic background of bipectinata and the reciprocal Y chromosome introgression were unsuccessful as all males in second backcross generation were sterile. Neither MHS genes nor cytoplasm was found important for sterility. This suggests the involvement of X-Y, X-autosomes or polygenic interactions in hybrid male sterility. In bipectinata--malerkotliana and parabipectinata--malerkotliana species pairs, Y chromosome substitution in reciprocal crosses did not affect male fertility. Backcross analyses also show no involvement of MHS genes or cytoplasm in hybrid male sterility in these two species pairs. Therefore, X- autosome interaction or polygenic interaction is supposed to be involved in hybrid male sterility in these two species pairs. These findings also provide evidence that even in closely related species, genetic interactions underlying hybrid male sterility may vary.

  9. Real-time PCR assay for rapid qualitative and quantitative detection of Entamoeba histolytica.

    Science.gov (United States)

    Orosz, Erika; Perkátai, Katalin; Kapusinszky, Beatrix; Farkas, Agnes; Kucsera, István

    2012-12-01

    Simple real-time PCR assay with one set of primer and probe for rapid, sensitive qualitative and quantitative detection of Entamoeba histolytica has been used. Consensus sequences were used to amplify a species-specific region of the 16S rRNA gene, and fluorescence resonance energy transfer hybridization probes were used for detection in a LightCycler platform (Roche). The anchor probe sequence was designed to be a perfect match for the 16S rRNA gene of Entamoeba species, while the acceptor probe sequence was designed for Entamoeba histolytica, which allowed differentiation. The performed characteristics of the real-time PCR assay were compared with ELISA antigen and microscopical detection from 77 samples of individuals with suspected clinical diagnosis of imported E. histolytica infection. Stool and liver abscess pus samples were examined with analytical sensitivity of 5 parasites per PCR reaction. The melting curve means Tms (standard deviation) in clinical isolates were 54°C. The real-time assay was 100% sensitive and specific for differentiation of Entamoeba histolytica, compared with conventional ELISA or microscopy. This real-time PCR assay with melting curve analysis is rapid, and specific for the detection and differentiation of Entamoeba histolytica. The suitability for routine use of this assay in clinical diagnostic laboratories is discussed.

  10. Discrimination of Entamoeba moshkovskii in patients with gastrointestinal disorders by single-round PCR.

    Science.gov (United States)

    Nazemalhosseini Mojarad, Ehsan; Nochi, Zahra; Sahebekhtiari, Navid; Rostami Nejad, Mohammad; Dabiri, Hossein; Zali, Mohammad Reza; Kazemi, Bahram; Haghighi, Ali

    2010-03-01

    Entamoeba moshkovskii and Entamoeba dispar are impossible to differentiate microscopically from the pathogenic species Entamoeba histolytica. There are limited data on the prevalence of these commensal parasites in Iran. We utilized a single-round PCR assay to determine the prevalence of E. moshkovskii, E. dispar, and E. histolytica in stool samples from Iranian patients infected with gastrointestinal disorders. After culturing of microscopy-positive isolates and extraction of DNA, PCR was carried out to differentiate the Entamoeba isolates. Out of 3,825 stool samples examined by microscopy, 58 specimens (1.52%) were infected with E. histolytica, E. dispar, or E. moshkovskii. By PCR, 2 E. histolytica (3.45%), 53 E. dispar (91.37%), 2 E. moshkovskii (3.45%), and one mixed E. dispar/E. moshkovskii infection (1.73%) were detected. In view of the reporting of E. moshkovskii in this study in Iran and the difficulty in discriminating this ameba from two similar Entamoeba spp. by microscopy, we recommend the single-round PCR assay as an alternative tool in routine diagnosis and in epidemiological studies of amebiasis.

  11. 齿龈内阿米巴的检出率及培养成活率与口腔共生菌的关系研究%The detection rate of Entamoeba gingivalis and the relation between the survival rate of cultures and oral symbiotic bateria

    Institute of Scientific and Technical Information of China (English)

    刘光英; 陈金富; 温旺荣

    2001-01-01

    @@ 齿龈内阿米巴(Entamoeba gingivalis,E.g)寄生于人及多种哺乳动物口腔龈沟、牙垢的一种原虫,它是牙周病病原体之一,提高它在口腔的检出率对疾病防治和获取虫体提供研究有一定意义;为了研究需要,培养大量的虫体能否成功与培养基的种类、pH、培养温度有关外,亦与细菌有关.我们经多年培养发现,在改良的LES培养基液面若有一层菌膜形成,就可能有E.g生长,否则就少虫或无虫生长,哪些细菌能促进E.g生长、繁殖?国内未见报道,国外仅Gannon等报道小肠结肠炎耶尔森氏菌有促进E.g生长作用,为此,进行E.g培养成功率与口腔共生菌的关系研究.

  12. The application of exogenous plasmid on the research of Entamoeba histolytica%外源质粒在溶组织内阿米巴研究中的应用

    Institute of Scientific and Technical Information of China (English)

    路睿; 陈建平

    2008-01-01

    溶组织内阿米巴是一种重要的致病性肠道原虫,可以引起阿米巴痢疾、阿米巴肝脓肿等疾病,甚至引起死亡,对其进行深入研究具有重要意义.外源质粒作为一种介导基因操作的手段,在研究溶组织内阿米巴的基因结构、基因表达调控和致病性的过程中均被广泛应用.该文就外源质粒在溶组织内阿米巴研究中的应用作一综述.%Entamoeba histolytica is an intestinal parasite and the causative agent of amoebiasis, which is a significant source of morbidity and mortality in developing countries. Plasmid-mediated gene transfer has been widely used as a powerful tool for the genetic manipulation and functional analysis of Entamoeba histolyti-ca. This paper reviewed the recent application of exogenous plasmid in the research of Entamoeba histolytica.

  13. Genetic and non-iodine-related factors in the aetiology of nodular goitre

    DEFF Research Database (Denmark)

    Knudsen, Nils; Brix, Thomas Heiberg

    2014-01-01

    Genetic and a large number of environmental non-iodine-related factors play a role in the cause of nodular goitre. Most evidence for the influence of genetic and environmental factors in the cause of goitre is from cross-sectional, population-based studies. Only a few studies have included...... prospective data on risk factors for nodular goitre, although few prospective data are available on the effect of iodine and tobacco smoking on goitre development. Goitre is not one single phenotype. Many epidemiological studies do not distinguish diffuse from nodular goitre, as the investigated parameter...... is often thyroid volume or frequency with increased thyroid volume. Moreover, information on the presence and effect of gene-environment, gene-gene, and environment-environment effect modifications is limited. Thus, firm conclusions about the relative contributions and causality of the investigated risk...

  14. Genetic evidence for common pathways in human age-related diseases.

    Science.gov (United States)

    Johnson, Simon C; Dong, Xiao; Vijg, Jan; Suh, Yousin

    2015-10-01

    Aging is the single largest risk factor for chronic disease. Studies in model organisms have identified conserved pathways that modulate aging rate and the onset and progression of multiple age-related diseases, suggesting that common pathways of aging may influence age-related diseases in humans as well. To determine whether there is genetic evidence supporting the notion of common pathways underlying age-related diseases, we analyzed the genes and pathways found to be associated with five major categories of age-related disease using a total of 410 genomewide association studies (GWAS). While only a small number of genes are shared among all five disease categories, those found in at least three of the five major age-related disease categories are highly enriched for apoliprotein metabolism genes. We found that a more substantial number of gene ontology (GO) terms are shared among the 5 age-related disease categories and shared GO terms include canonical aging pathways identified in model organisms, such as nutrient-sensing signaling, translation, proteostasis, stress responses, and genome maintenance. Taking advantage of the vast amount of genetic data from the GWAS, our findings provide the first direct evidence that conserved pathways of aging simultaneously influence multiple age-related diseases in humans as has been demonstrated in model organisms. © 2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  15. Common genetic variability in ESR1 and EGF in relation to endometrial cancer risk and survival

    OpenAIRE

    Einarsdóttir, K; Darabi, H; Czene, K.; Li, Y; Low, Y.L.; Y. Q. Li; Bonnard, C.; Wedrén, S.; Liu, E. T.; Hall, P; Liu, J; Humphreys, K.

    2009-01-01

    We investigated common genetic variation in the entire ESR1 and EGF genes in relation to endometrial cancer risk, myometrial invasion and endometrial cancer survival. We genotyped a dense set of single-nucleotide polymorphisms (SNPs) in both genes and selected haplotype tagging SNPs (tagSNPs). The tagSNPs were genotyped in 713 Swedish endometrial cancer cases and 1567 population controls and the results incorporated into logistic regression and Cox proportional hazards models. We found five a...

  16. A proteomic and cellular analysis of uropods in the pathogen Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    Jacques Marquay Markiewicz

    Full Text Available Exposure of Entamoeba histolytica to specific ligands induces cell polarization via the activation of signalling pathways and cytoskeletal elements. The process leads to formation of a protruding pseudopod at the front of the cell and a retracting uropod at the rear. In the present study, we show that the uropod forms during the exposure of trophozoites to serum isolated from humans suffering of amoebiasis. To investigate uropod assembly, we used LC-MS/MS technology to identify protein components in isolated uropod fractions. The galactose/N-acetylgalactosamine lectin, the immunodominant antigen M17 (which is specifically recognized by serum from amoeba-infected persons and a few other cells adhesion-related molecules were primarily involved. Actin-rich cytoskeleton components, GTPases from the Rac and Rab families, filamin, α-actinin and a newly identified ezrin-moesin-radixin protein were the main factors found to potentially interact with capped receptors. A set of specific cysteine proteases and a serine protease were enriched in isolated uropod fractions. However, biological assays indicated that cysteine proteases are not involved in uropod formation in E. histolytica, a fact in contrast to the situation in human motile immune cells. The surface proteins identified here are testable biomarkers which may be either recognized by the immune system and/or released into the circulation during amoebiasis.

  17. Data set for the proteomics analysis of the endomembrane system from the unicellular Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Doranda Perdomo

    2014-12-01

    Full Text Available Entamoeba histolytica is the protozoan parasite agent of amebiasis, an infectious disease of the human intestine and liver. This parasite contact and kills human cells by an active process involving pathogenic factors. Cellular traffic and secretion activities are poorly characterized in E. histolytica. In this work, we took advantage of a wide proteomic analysis to search for principal components of the endomembrane system in E. histolytica. A total of 5683 peptides matching with 1531 proteins (FDR of 1% were identified which corresponds to roughly 20% of the total amebic proteome. Bioinformatics investigations searching for domain homologies (Smart and InterProScan programs and functional descriptions (KEGG and GO terms allowed this data to be organized into distinct categories. This data represents the first in-depth proteomics analysis of subcellular compartments in E. histolytica and allows a detailed map of vesicle traffic components in an ancient single-cell organism that lacks a stereotypical ER and Golgi apparatus to be established. The data are related to [1].

  18. Identification of the Virulence Landscape Essential for Entamoeba histolytica Invasion of the Human Colon

    Science.gov (United States)

    Hon, Chung-Chau; Dillies, Marie-Agnès; Avé, Patrick; Coppée, Jean-Yves; Labruyère, Elisabeth; Guillén, Nancy

    2013-01-01

    Entamoeba histolytica is the pathogenic amoeba responsible for amoebiasis, an infectious disease targeting human tissues. Amoebiasis arises when virulent trophozoites start to destroy the muco-epithelial barrier by first crossing the mucus, then killing host cells, triggering inflammation and subsequently causing dysentery. The main goal of this study was to analyse pathophysiology and gene expression changes related to virulent (i.e. HM1:IMSS) and non-virulent (i.e. Rahman) strains when they are in contact with the human colon. Transcriptome comparisons between the two strains, both in culture conditions and upon contact with human colon explants, provide a global view of gene expression changes that might contribute to the observed phenotypic differences. The most remarkable feature of the virulent phenotype resides in the up-regulation of genes implicated in carbohydrate metabolism and processing of glycosylated residues. Consequently, inhibition of gene expression by RNA interference of a glycoside hydrolase (β-amylase absent from humans) abolishes mucus depletion and tissue invasion by HM1:IMSS. In summary, our data suggest a potential role of carbohydrate metabolism in colon invasion by virulent E. histolytica. PMID:24385905

  19. A Proteomic and Cellular Analysis of Uropods in the Pathogen Entamoeba histolytica

    Science.gov (United States)

    Marquay Markiewicz, Jacques; Syan, Sylvie; Hon, Chung-Chau; Weber, Christian; Faust, Daniela; Guillen, Nancy

    2011-01-01

    Exposure of Entamoeba histolytica to specific ligands induces cell polarization via the activation of signalling pathways and cytoskeletal elements. The process leads to formation of a protruding pseudopod at the front of the cell and a retracting uropod at the rear. In the present study, we show that the uropod forms during the exposure of trophozoites to serum isolated from humans suffering of amoebiasis. To investigate uropod assembly, we used LC-MS/MS technology to identify protein components in isolated uropod fractions. The galactose/N-acetylgalactosamine lectin, the immunodominant antigen M17 (which is specifically recognized by serum from amoeba-infected persons) and a few other cells adhesion-related molecules were primarily involved. Actin-rich cytoskeleton components, GTPases from the Rac and Rab families, filamin, α-actinin and a newly identified ezrin-moesin-radixin protein were the main factors found to potentially interact with capped receptors. A set of specific cysteine proteases and a serine protease were enriched in isolated uropod fractions. However, biological assays indicated that cysteine proteases are not involved in uropod formation in E. histolytica, a fact in contrast to the situation in human motile immune cells. The surface proteins identified here are testable biomarkers which may be either recognized by the immune system and/or released into the circulation during amoebiasis. PMID:21483708

  20. [Environmental and genetic variables related with alterations in language acquisition in early childhood].

    Science.gov (United States)

    Moriano-Gutierrez, A; Colomer-Revuelta, J; Sanjuan, J; Carot-Sierra, J M

    2017-01-01

    A great deal of research has addressed problems in the correct acquisition of language, but with few overall conclusions. The reasons for this lie in the individual variability, the existence of different measures for assessing language and the fact that a complex network of genetic and environmental factors are involved in its development. To review the environmental and genetic variables that have been studied to date, in order to gain a better under-standing of the causes of specific language impairment and create new evidence that can help in the development of screening systems for the early detection of these disorders. The environmental variables related with poorer early child language development include male gender, low level of education of the mother, familial history of problems with language or psychiatric problems, perinatal problems and health problems in early childhood. Bilingualism seems to be a protective factor. Temperament and language are related. Within the genetic factors there are several specific genes associated with language, two of which have a greater influence on its physiological acquisition: FOXP2 and CNTNAP2. The other genes that are most related with specific language disorders are ATP2C2, CMIP, ROBO2, ZNF277 and NOP9. The key to comprehending the development of specific language disorders lies in reaching an understanding of the true role played by genes in the ontogenesis, in the regulation of the different developmental processes, and how this role is modulated by the environment.

  1. Use of a twin dataset to identify AMD-related visual patterns controlled by genetic factors

    Science.gov (United States)

    Quellec, Gwénolé; Abràmoff, Michael D.; Russell, Stephen R.

    2010-03-01

    The mapping of genotype to the phenotype of age-related macular degeneration (AMD) is expected to improve the diagnosis and treatment of the disease in a near future. In this study, we focused on the first step to discover this mapping: we identified visual patterns related to AMD which seem to be controlled by genetic factors, without explicitly relating them to the genes. For this purpose, we used a dataset of eye fundus photographs from 74 twin pairs, either monozygotic twins, who have the same genotype, or dizygotic twins, whose genes responsible for AMD are less likely to be identical. If we are able to differentiate monozygotic twins from dizygotic twins, based on a given visual pattern, then this pattern is likely to be controlled by genetic factors. The main visible consequence of AMD is the apparition of drusen between the retinal pigment epithelium and Bruch's membrane. We developed two automated drusen detectors based on the wavelet transform: a shape-based detector for hard drusen, and a texture- and color- based detector for soft drusen. Forty visual features were evaluated at the location of the automatically detected drusen. These features characterize the texture, the shape, the color, the spatial distribution, or the amount of drusen. A distance measure between twin pairs was defined for each visual feature; a smaller distance should be measured between monozygotic twins for visual features controlled by genetic factors. The predictions of several visual features (75.7% accuracy) are comparable or better than the predictions of human experts.

  2. Genetic characterization of indigenous peoples from Oaxaca, Mexico, and its relation to linguistic and geographic isolation.

    Science.gov (United States)

    Quinto-Cortés, Consuelo D; Arriola, Luis A; García-Hughes, Gianella; García-López, Rodrigo; Molina, Diana P; Flores, Margarita; Palacios, Rafael; Piñero, Daniel

    2010-08-01

    We used 15 short tandem repeat (STR) loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818, and FGA) to genetically characterize 361 individuals from 11 indigenous populations (Amuzgo, Chinanteco, Chontal, Huave, Mazateco, Mixe, Mixteco, Triqui, Zapoteco del Istmo, Zapoteco del Valle, and Zoque) from Oaxaca, Mexico. We also used previously published data from other Mexican peoples (Maya, Chol, Tepehua, Otomí, and Mestizos from northern and central Mexico) to delineate genetic relations, for a total of 541 individuals. Average heterozygosity (H) was lower in most populations from Oaxaca (range 0.687 in Zoque to 0.756 in Chontal) than values observed in Mestizo populations from Mexico (0.758 and 0.793 in central and northern Mestizo, respectively) but higher than values observed in other Amerindian populations from South America; the same relation was true for the number of alleles (n(a) ). We tested (using the software Structure) whether major geographic or linguistic barriers to gene flow existed among the populations of Oaxaca and found that the populations appeared to constitute one or two genetic groups, suggesting that neither geographic location nor linguistics had an effect on the genetic structure of these culturally and linguistically highly diverse indigenous peoples. Moreover, we found a low but statistically significant between-population differentiation. In addition, the genetic structure of Oaxacan populations did not fit an isolation-by-distance model. Finally, using AMOVA and a Bayesian clustering approach, we did not detect significant geographic or linguistic barriers to gene flow within Oaxaca. These results suggest that the indigenous communities of Oaxaca, although culturally isolated, can be genetically defined as a large, nearly panmictic population in which migration could be a more important population mechanism than genetic drift. Finally, compared with outgroups in Mexico (both

  3. Genetic Relation Analysis on Ramie [Boehmeria nivea (L.) Gaud.] Inbred Lines by SRAP Markers

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The objective of this article is to reveal the variations of ramie inbred lines in DNA level and discuss their molecular background to provide a theoretical basis for ramie cross breeding. In the present study, the genetic relationships among 33 inbred line accessions and two wild types that originated from China and Brazil were estimated using sequence-related amplified polymorphism (SRAP) markers. The results showed that 33 out of 81 primer combinations turned out to be polymorphic and 332 polymorphism bands were obtained. On the basis of the appearance of the markers, the genetic relationships were analyzed using unweighted pair-group method of arithmetic average cluster analysis (UPGMA), and the genetic Jaccard similarity coefficients were calculated. The inbred-lines originating from China and Brazil formed a cluster suggesting a possibility that the Brazilian cultivars could have developed from cultivars introduced from China. Within ramie inbred-lines, the groupings also indicated that the greatest genetic relationship among cultivars was correlated to the region of origin of cultivars. The results provided the evidence that SRAP was an efficient approach, suitable for taxonomic analysis of ramie inbred lines. To the authors' knowledge, this is the first application of SRAP marker on the systematics of ramie inbred lines.

  4. Electroretinogram analysis of relative spectral sensitivity in genetically identified dichromatic macaques.

    Science.gov (United States)

    Hanazawa, A; Mikami, A; Sulistyo Angelika, P; Takenaka, O; Goto, S; Onishi, A; Koike, S; Yamamori, T; Kato, K; Kondo, A; Suryobroto, B; Farajallah, A; Komatsu, H

    2001-07-03

    The retinas of macaque monkeys usually contain three types of photopigment, providing them with trichromatic color vision homologous to that of humans. However, we recently used molecular genetic analysis to identify several macaques with a dichromatic genotype. The affected X chromosome of these animals contains a hybrid gene of long-wavelength-sensitive (L) and middle-wavelength-sensitive (M) photopigments instead of separate genes encoding L and M photopigments. The product of the hybrid gene exhibits a spectral sensitivity close to that of M photopigment; consequently, male monkeys carrying the hybrid gene are genetic protanopes, effectively lacking L photopigment. In the present study, we assessed retinal expression of L photopigment in monkeys carrying the hybrid gene. The relative sensitivities to middle-wavelength (green) and long-wavelength (red) light were measured by electroretinogram flicker photometry. We found the sensitivity to red light to be extremely low in protanopic male monkeys compared with monkeys with the normal genotype. In female heterozygotes, sensitivity to red light was intermediate between the genetic protanopes and normal monkeys. Decreased sensitivity to long wavelengths was thus consistent with genetic loss of L photopigment.

  5. Genetic investigation of bisphosphonate-related osteonecrosis of jaw (BRONJ via whole exome sequencing and bioinformatics.

    Directory of Open Access Journals (Sweden)

    Jee-Hwan Kim

    Full Text Available Complications associated with the use of bisphosphonate (BP have risen over the years due to an increase in the prescription of BP. BP-related osteonecrosis of jaw (BRONJ, one of the complications linked to the consumption of BP, greatly affects patients with minor dental trauma, incurring a long healing period. While BRONJ afflicts only a minority of patients prescribed with BP, BRONJ is a multigenic disease affected both by environmental and genetic factors having a distinctive phenotype. This study aims to discover genetic biomarkers associated with BRONJ via whole exome sequencing (WES followed by statistical analysis. Sixteen individuals who had been prescribed with bisphosphonate medication and diagnosed as BRONJ were chosen and each individual's saliva sample was collected for WES. 126 randomized subsamples from the GSK project representing 109 male and 17 female Koreans were used as a control data set. Fisher's exact test was carried out to assess the significance of genetic variants in BRONJ patients. Gene set enrichment analysis (GSEA (DAVID Bioinformatics Resource 6.7 was used to perform a cluster analysis of variants found from Fisher's exact test. The results from this study suggest that BRONJ-inducing factors are genetically associated and BRONJ occurs due to the malfunctioning of post-translational modification in osteoclast leading to the impairment of cell morphology and adhesion.

  6. Progress and Prospects in Human Genetic Research into Age-Related Hearing Impairment

    Directory of Open Access Journals (Sweden)

    Yasue Uchida

    2014-01-01

    Full Text Available Age-related hearing impairment (ARHI is a complex, multifactorial disorder that is attributable to confounding intrinsic and extrinsic factors. The degree of impairment shows substantial variation between individuals, as is also observed in the senescence of other functions. This individual variation would seem to refute the stereotypical view that hearing deterioration with age is inevitable and may indicate that there is ample scope for preventive intervention. Genetic predisposition could account for a sizable proportion of interindividual variation. Over the past decade or so, tremendous progress has been made through research into the genetics of various forms of hearing impairment, including ARHI and our knowledge of the complex mechanisms of auditory function has increased substantially. Here, we give an overview of recent investigations aimed at identifying the genetic risk factors involved in ARHI and of what we currently know about its pathophysiology. This review is divided into the following sections: (i genes causing monogenic hearing impairment with phenotypic similarities to ARHI; (ii genes involved in oxidative stress, biologic stress responses, and mitochondrial dysfunction; and (iii candidate genes for senescence, other geriatric diseases, and neurodegeneration. Progress and prospects in genetic research are discussed.

  7. Genetic structure of populations and conservation issues relating to an endangered catfish, Clarias batrachus, in India.

    Science.gov (United States)

    Khedkar, Gulab D; Tiknaik, Anita; Kalyankar, Amol D; A, Chandra Sekhar Reddy; Khedkar, Chandraprakash D; Ron, Tetsuzan Benny; Haymer, David

    2016-01-01

    The Asian catfish, Clarias batrachus (Linnaeus, 1758), is a highly valued species endemic to India that is currently in drastic decline in most of its natural habitat. The present study was undertaken to document the genetic structure of populations of this species using mitochondrial DNA markers, specifically from the cytochrome B and D-loop regions. Specimens from eight wild populations were collected and analyzed from different regions in India. The genetic variation within and among populations was evaluated using a range of descriptive statistics. The analysis described here provides a broad and consistent view of population structure and demographic history of populations of C. batrachus. Although there was some genetic structuring consistent with regional differences, all eight populations examined here showed relatively low levels of genetic variation in terms of both haplotype and nucleotide diversities in the different analyses used. However, a number of private haplotypes were discovered, and this may provide valuable information for future selective breeding program and conservation management. The results may aid in the design and implementation of strategies for the future management of this endangered catfish C. batrachus in India.

  8. Association study of functional genetic variants of innate immunity related genes in celiac disease

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    Martín J

    2005-08-01

    Full Text Available Abstract Background Recent evidence suggest that the innate immune system is implicated in the early events of celiac disease (CD pathogenesis. In this work for the first time we have assessed the relevance of different proinflammatory mediators typically related to innate immunity in CD predisposition. Methods We performed a familial study in which 105 celiac families characterized by the presence of an affected child with CD were genotyped for functional polymorphisms located at regulatory regions of IL-1α, IL-1β, IL-1RN, IL-18, RANTES and MCP-1 genes. Familial data was analysed with a transmission disequilibrium test (TDT that revealed no statistically significant differences in the transmission pattern of the different genetic markers considered. Results The TDT analysis for IL-1α, IL-1β, IL-1RN, IL-18, and MCP-1 genes genetic variants did not reveal biased transmission to the affected offspring. Only a borderline association of RANTES promoter genetic variants with CD predisposition was observed. Conclusion Our results suggest that the analysed polymorphisms of IL-1α, IL-1β, IL-1RN, IL-18, RANTES and MCP-1 genes do not seem to play a major role in CD genetic predisposition in our population.

  9. Use of bacterially expressed dsRNA to downregulate Entamoeba histolytica gene expression.

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    Carlos F Solis

    Full Text Available BACKGROUND: Modern RNA interference (RNAi methodologies using small interfering RNA (siRNA oligonucleotide duplexes or episomally synthesized hairpin RNA are valuable tools for the analysis of gene function in the protozoan parasite Entamoeba histolytica. However, these approaches still require time-consuming procedures including transfection and drug selection, or costly synthetic molecules. PRINCIPAL FINDINGS: Here we report an efficient and handy alternative for E. histolytica gene down-regulation mediated by bacterial double-stranded RNA (dsRNA targeting parasite genes. The Escherichia coli strain HT115 which is unable to degrade dsRNA, was genetically engineered to produce high quantities of long dsRNA segments targeting the genes that encode E. histolytica beta-tubulin and virulence factor KERP1. Trophozoites cultured in vitro were directly fed with dsRNA-expressing bacteria or soaked with purified dsRNA. Both dsRNA delivery methods resulted in significant reduction of protein expression. In vitro host cell-parasite assays showed that efficient downregulation of kerp1 gene expression mediated by bacterial dsRNA resulted in significant reduction of parasite adhesion and lytic capabilities, thus supporting a major role for KERP1 in the pathogenic process. Furthermore, treatment of trophozoites cultured in microtiter plates, with a repertoire of eighty-five distinct bacterial dsRNA segments targeting E. histolytica genes with unknown function, led to the identification of three genes potentially involved in the growth of the parasite. CONCLUSIONS: Our results showed that the use of bacterial dsRNA is a powerful method for the study of gene function in E. histolytica. This dsRNA delivery method is also technically suitable for the study of a large number of genes, thus opening interesting perspectives for the identification of novel drug and vaccine targets.

  10. Investigation of Entamoeba histolytica in stool specimens by ELISA during a year

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    Mehmet Sinan Dal

    2011-03-01

    Full Text Available The aim of this study was to investigate Entamoebahistolytica in the stool samples that have beensent to microbiology laboratory by ELISA method.Materials and methods: This study was performed on800 stool specimens belonging to different age groupsand different patients sent to Microbiology Laboratory ofa State Hospital between January 2009 and December2009.Results: In this study Entamoeba histolytica/dispar cystsand/or trophozoites were observed in 31 (3.9% out of atotal of 800 stool specimens which were examined bynative-lugol. Entamoeba histolytica specific antigen wasinvestigated by ELISA in all stool specimens. Entamoebahistolytica specific antigen was detected in 12 (1.5% ofthese stool specimens. The diagnosis of amoebiasis forthe patients whose ELISA tests were “positive” and appropriatetherapy was begun.Conclusion: Entamoeba histolytica in the stool samplesshould be investigated and unnecessary treatmentsshould not given to patients. J Clin Exp Invest 2011; 2(1:50-54

  11. New Entamoeba group in howler monkeys (Alouatta spp.) associated with parasites of reptiles.

    Science.gov (United States)

    Villanueva-García, Claudia; Gordillo-Chávez, Elías José; Baños-Ojeda, Carlos; Rendón-Franco, Emilio; Muñoz-García, Claudia Irais; Carrero, Julio César; Córdoba-Aguilar, Alex; Maravilla, Pablo; Galian, José; Martínez-Hernández, Fernando; Villalobos, Guiehdani

    2017-08-01

    Our knowledge of the parasite species present in wildlife hosts is incomplete. Protozoans such as amoebae of the genus Entamoeba infect a large variety of vertebrate species, including NHPs. However, traditionally, their identification has been accomplished through microscopic evaluation; therefore, amoeba species have not always been identified correctly. We searched for Entamoeba spp. using a fragment of the small subunit rDNA in free-ranging howler monkeys (Alouatta palliata and A. pigra) from southeast Mexico. One hundred fifty five samples were collected, with 46 from A. palliata and 109 from A. pigra and 8 of the total samples were positive. We detected a new clade of Entamoeba, which was separated from other described species but closer to E. insolita, as well as an unnamed sequence typically found in iguana species with low shared identity values (<90%). We designated this new clade as conditional lineage 8 (CL8) and we have shown that members of this group are not exclusive to reptiles.

  12. Ultrastructural observation of human neutrophils during apoptotic cell death triggered by Entamoeba histolytica.

    Science.gov (United States)

    Sim, Seobo; Kim, Kyeong Ah; Yong, Tai-Soon; Park, Soon-Jung; Im, Kyung-il; Shin, Myeong Heon

    2004-12-01

    Neutrophils are important effector cells against protozoan extracellular parasite Entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. Apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. This study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by Entamoeba histolytica. Isolated human neutrophils from the peripheral blood were incubated with or without live trophozoites of E. histolytica and examined by transmission electron microscopy (TEM). Neutrophils incubated with E. histolytica were observed to show apoptotic characteristics, such as compaction of the nuclear chromatin and swelling of the nuclear envelop. In contrast, neutrophils incubated in the absence of the amoeba had many protrusions of irregular cell surfaces and heterogenous nuclear chromatin. Therefore, it is suggested that Entamoeba-induced neutrophil apoptosis contribute to prevent unwanted tissue inflammation and damage in the amoeba-invaded lesions in vivo.

  13. Amebae resembling Entamoeba gingivalis in the genital tracts of IUD users.

    Science.gov (United States)

    deMoraes-Ruehsen, M; McNeill, R E; Frost, J K; Gupta, P K; Diamond, L S; Honigberg, B M

    1980-01-01

    A total of 2,252 vaginopancervical (Fast) smears were studied as a continuation of an ongoing program to further investigate the occurrence of amebae in the genital tracts of women using intrauterine devices (IUDs). Of the 947 IUD users, 1% harbored trophic amebae. No amebae, however, were found in any of the 1,164 smears from non-IUD wearers. In all instances the amebae were associated with Actinomyces. Both organisms disappeared promptly after removal of the IUD. In preparations stained according to the Papanicolaou, iron-hematoxylin and Gomori-Wheatley trichrome methods, the amebae could be diagnosed as belonging to the genus Entamoeba. These trophozoites failed to stain with fluorescein-labeled anti-Entamoeba-histolytica serum. Although on the basis of the presently available evidence these trophozoites cannot be assigned with certainty to any known species, they appear to share many morphologic characteristics with Entamoeba gingivalis.

  14. Close sequence identity between ribosomal DNA episomes of the non-pathogenic Entamoeba dispar and pathogenic Entamoeba histolytica

    Indian Academy of Sciences (India)

    Jaishree Paul; Alok Bhattacharya; Sudha Bhattacharya

    2002-11-01

    Entamoeba dispar and Entamoeba histolytica are now recognized as two distinct species – the former being nonpathogenic to humans. We had earlier studied the organization of ribosomal RNA genes in E. histolytica. Here we report the analysis of ribosomal RNA genes in E. dispar. The rRNA genes of E. dispar, like their counterpart in E. histolytica are located on a circular rDNA molecule. From restriction map analysis, the size of E. dispar rDNA circle was estimated to be 24.4 kb. The size was also confirmed by linearizing the circle with BsaHI, and by limited DNAseI digestion. The restriction map of the E. dispar rDNA circle showed close similarity to EhR1, the rDNA circle of E. histolytica strain HM-1:IMSS which has two rDNA units per circle. The various families of short tandem repeats found in the upstream and downstream intergenic spacers (IGS) of EhR1 were also present in E. dispar. Partial sequencing of the cloned fragments of E. dispar rDNA and comparison with EhR1 revealed only 2.6% to 3.8% sequence divergence in the IGS. The region Tr and the adjoining PvuI repeats in the IGS of EhR1, which are missing in those E. histolytica strains that have one rDNA unit per circle, were present in the E. dispar rDNA circle. Such close similarity in the overall organization and sequence of the IGS of rDNAs of two different species is uncommon. In fact the spacer sequences were only slightly more divergent than the 18S rRNA gene sequence which differs by 1.6% in the two species. The most divergent sequence between E. histolytica and E. dispar was the internal transcribed spacer, ITS2. Therefore, it was concluded that probes derived from the ITS1 and ITS2 sequences would be more reliable and reproducible than probes from the IGS regions used earlier for identifying these species.

  15. Feed-forward regulation of phagocytosis by Entamoeba histolytica.

    Science.gov (United States)

    Sateriale, Adam; Vaithilingam, Archana; Donnelly, Liam; Miller, Peter; Huston, Christopher D

    2012-12-01

    The parasitic protozoan Entamoeba histolytica is aptly named for its capacity to destroy host tissue. When E. histolytica trophozoites invade the lamina propria of a host colon, extracellular matrices are degraded while host cells are killed and phagocytosed. The ability of E. histolytica to phagocytose host cells correlates with virulence in vivo. In order to better understand the mechanism of phagocytosis, we used an E. histolytica Affymetrix microarray chip to measure the total gene expression of phagocytic and nonphagocytic subpopulations. Using paramagnetic beads coated with a known host ligand that stimulates phagocytosis, phagocytic and nonphagocytic amoebae from a single culture were purified. Microarray analysis of the subpopulations identified 121 genes with >2-fold higher expression in phagocytic than in nonphagocytic amoebae. Functional annotation identified genes encoding proteins involved in actin binding and cytoskeletal organization as highly enriched gene clusters. Post hoc analyses of selected genes showed that the gene expression profile identified in the microarray experiment did not exist prior to cell sorting but rather was stimulated through phagocytosis. Further, these expression profiles correlated with an increase in phagocytic ability, as E. histolytica cultures exposed to an initial stimulus of phagocytosis showed increased phagocytic ability upon a second stimulus. To our knowledge, this is the first description of such feed-forward regulation of gene expression and phagocytic ability in a phagocyte.

  16. Molecular and biochemical characterization of Entamoeba histolytica fructokinase.

    Science.gov (United States)

    Matt, Julia; Duchêne, Michael

    2015-05-01

    Entamoeba histolytica is the causative agent of amoebic dysentery and liver abscess. The medium for its axenic culture contains glucose as energy source, and we addressed the question whether E. histolytica can also use fructose instead. As the amoebic hexokinases do not phosphorylate fructose, a separate fructokinase is essential. The genome project revealed a single candidate gene encoding an E. histolytica homolog of bacterial fructokinases. This gene was cloned, and the recombinant enzyme had a magnesium-dependent fructose 6-kinase activity (EC 2.7.1.4) with a K m for fructose of 0.156 mM and a V max of 131 U/mg protein. Recombinant fructokinase also showed a much weaker mannokinase activity, but no activity with glucose or galactose. The amoebae could be switched from glucose to fructose medium without any detectable consequence on doubling time. Fructokinase messenger RNA (mRNA) was modestly but significantly upregulated in amoebae switched to fructose medium as well as in fructose-adapted E. histolytica.

  17. Biochemical characterization of the DNA ligase I from Entamoeba histolytica.

    Science.gov (United States)

    Cardona-Felix, Cesar S; Pastor-Palacios, Guillermo; Cardenas, Helios; Azuara-Liceaga, Elisa; Brieba, Luis G

    2010-11-01

    DNA ligases play an essential role in DNA replication and repair. Herein, we report the cloning and biochemical characterization of DNA ligase I from the protozoan parasite Entamoeba histolytica (EhDNAligI). EhDNAligI is an ATP-dependent DNA ligase of 685 amino acids with 35% identity to human DNA ligase I. This report shows that heterologous expressed EhDNAligI is able to perform the three conserved steps of a DNA ligation reaction: adenylation, binding to a 5'-phosphorylated nicked DNA substrate and sealing of the nick. EhDNAligI is strongly inhibited by NaCl and displays optimal activity at pH 7.5. EhDNAligI uses Mn2+ or Mg2+ as metal cofactors and ATP as nucleotide cofactor. EhDNAligI has a nicked DNA binding constant of 6.6microM and follows Michaelis-Menten steady-state kinetics with a K(m) ATP of 64nM and a k(cat) of 2.4min(-1). Accordingly to its properties as a family I DNA ligase, EhDNAligI is able to ligate a RNA strand upstream of a nucleic acid nick, but not in the downstream or the template position. We propose that EhDNAligI is involved in sealing DNA nicks during lagging strand synthesis and may have a role in base excision repair in E. histolytica.

  18. Chitin synthetase in encysting Giardia lamblia and Entamoeba invadens

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.; Gillin, F.D.

    1987-05-01

    Giardia lamblia (Gl) and Entamoeba invadens (Ei) are protozoan parasites with two morphologic stages in their life cycles. Motile trophozoites colonize the intestine of humans and reptiles respectively. Water resistant cysts, which can survive outside the host, transmit infection. In vitro cyst formation of Ei from trophozoites has been reported, and the authors have recently induced in vitro encystation of Gl. Although the cyst walls of both parasites contain chitin, it synthesis by encysting trophozoites has not been reported. The authors now show that encystation conditions greatly increase chitin synthetase (CS) specific activity (incorporation of /sup 3/H GlcNAc from UDP-GlcNAc into TCA-or alcohol-precipitable material). Extracts of encysting Gl incorporated 3.6 nmol/mg protein in 5 hr compared to < 0.005 in controls. Extracts of encysting Fi incorporated 4.8 n mol/mg protein, compared to 1.7 in the control. CS activity of both parasites requires preformed chitin. The Gl enzyme requires a reducing agent, is inhibited by digitonin and the CS inhibitors, polyoxin D and Nikkomycin, but not by tunicamycin. The product is digested by chitinase. Ei enzyme does not require a reducing agent and is stimulated by 1 mg/ml digitonin, but inhibited by higher concentrations. These studies demonstrate CS enzymes which may play important roles in encystation of Gl and Ei.

  19. Entamoeba histolytica infection in children and protection from subsequent amebiasis.

    Science.gov (United States)

    Haque, Rashidul; Mondal, Dinesh; Duggal, Priya; Kabir, Mamun; Roy, Shantanu; Farr, Barry M; Sack, R Bradley; Petri, William A

    2006-02-01

    The contribution of amebiasis to the burden of diarrheal disease in children and the degree to which immunity is acquired from natural infection were assessed in a 4-year prospective observational study of 289 preschool children in an urban slum in Dhaka, Bangladesh. Entamoeba histolytica infection was detected at least once in 80%, and repeat infection in 53%, of the children who completed 4 years of observation. Annually there were 0.09 episodes/child of E. histolytica-associated diarrhea and 0.03 episodes/child of E. histolytica-associated dysentery. Fecal immunoglobulin A (IgA) anti-parasite Gal/GalNAc lectin carbohydrate recognition domain (anti-CRD) was detected in 91% (183/202) of the children at least once and was associated with a lower incidence of infection and disease. We concluded that amebiasis was a substantial burden on the overall health of the cohort children. Protection from amebiasis was associated with a stool anti-CRD IgA response. The challenge of producing an effective vaccine will be to improve upon naturally acquired immunity, which does not provide absolute protection from reinfection.

  20. Entamoeba histolytica: Adhesins and Lectins in the Trophozoite Surface

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    Magdalena Aguirre García

    2015-02-01

    Full Text Available Entamoeba histolytica is the causative agent of amebiasis in humans and is responsible for 100,000 deaths annually, making it the third leading cause of death due to a protozoan parasite. Pathogenesis appears to result from the potent cytotoxic activity of the parasite, which kills host cells within minutes. Although the mechanism is unknown, it is well established to be contact-dependent. The life cycle of the parasite alternates with two forms: the resistant cyst and the invasive trophozoite. The adhesive interactions between the parasite and surface glycoconjugates of host cells, as well as those lining the epithelia, are determinants for invasion of human tissues, for its cytotoxic activity, and finally for the outcome of the disease. In this review we present an overview of the information available on the amebic lectins and adhesins that are responsible of those adhesive interactions and we also refer to their effect on the host immune response. Finally, we present some concluding remarks and perspectives in the field.

  1. Immune evasion mechanisms of Entamoeba histolytica: progression to disease

    Directory of Open Access Journals (Sweden)

    Sharmin eBegum

    2015-12-01

    Full Text Available Entamoeba histolytica (Eh is a protozoan parasite that infects 10% of the world’s population and results in 100,000 deaths/year from amebic dysentery and/or liver abscess. In most cases, this extracellular parasite colonizes the colon by high affinity binding to MUC2 mucin without disease symptoms, whereas in some cases, Eh triggers an aggressive inflammatory response upon invasion of the colonic mucosa. The specific host-parasite factors critical for disease pathogenesis are still not well characterized. From the parasite, the signature events that lead to disease progression are cysteine protease cleavage of the C-terminus of MUC2 that dissolves the mucus layer followed by Eh binding and cytotoxicity of the mucosal epithelium. The host mounts an ineffective excessive host pro-inflammatory response following contact with host cells that causes tissue damage and participates in disease pathogenesis as Eh escapes host immune clearance by mechanisms that are not completely understood. Ameba can modulate or destroy effector immune cells by inducing neutrophil apoptosis and suppressing respiratory burst or nitric oxide (NO production from macrophages. Eh adherence to the host cells also induce multiple cytotoxic effects that can promote cell death through phagocytosis, apoptosis or by trogocytosis (ingestion of living cells that might play critical roles in immune evasion. This review focuses on the immune evasion mechanisms that Eh uses to survive and induce disease manifestation in the host.

  2. Entamoeba histolytica Trophozoites and Lipopeptidophosphoglycan Trigger Human Neutrophil Extracellular Traps.

    Science.gov (United States)

    Ávila, Eva E; Salaiza, Norma; Pulido, Julieta; Rodríguez, Mayra C; Díaz-Godínez, César; Laclette, Juan P; Becker, Ingeborg; Carrero, Julio C

    2016-01-01

    Neutrophil defense mechanisms include phagocytosis, degranulation and the formation of extracellular traps (NET). These networks of DNA are triggered by several immune and microbial factors, representing a defense strategy to prevent microbial spread by trapping/killing pathogens. This may be important against Entamoeba histolytica, since its large size hinders its phagocytosis. The aim of this study was to determine whether E. histolytica and their lipopeptidophosphoglycan (EhLPPG) induce the formation of NETs and the outcome of their interaction with the parasite. Our data show that live amoebae and EhLPPG, but not fixed trophozoites, induced NET formation in a time and dose dependent manner, starting at 5 min of co-incubation. Although immunofluorescence studies showed that the NETs contain cathelicidin LL-37 in close proximity to amoebae, the trophozoite growth was only affected when ethylene glycol tetra-acetic acid (EGTA) was present during contact with NETs, suggesting that the activity of enzymes requiring calcium, such as DNases, may be important for amoeba survival. In conclusion, E. histolytica trophozoites and EhLPPG induce in vitro formation of human NETs, which did not affect the parasite growth unless a chelating agent was present. These results suggest that NETs may be an important factor of the innate immune response during infection with E. histolytica.

  3. A novel anti-inflammatory oligopeptide produced by Entamoeba histolytica.

    Science.gov (United States)

    Kretschmer, R R; Rico, G; Giménez, J A

    2001-02-01

    The monocyte locomotion inhibitory factor (MLIF), a heat-stable oligopeptide found in the supernatant fluid of Entamoeba histolytica axenic cultures was isolated by ultra-filtration, gel-sieve chromatography and high powered liquid chromatography (HPLC), and its primary structure (Met-Gln-Cys-Asn-Ser) established by Edman sequencing and mass-spectrometry (MS). A synthetic peptide had the same selective anti-inflammatory features as the native material in comparable concentrations: in vitro inhibition of the locomotion in human peripheral blood monocytes, and of the respiratory burst in the same cells and in human neutrophil polymorphonuclear leucocytes; and in vivo depression of delayed hypersensitivity skin reactions to dinitrochlorobenzene in guinea pigs. This oligopeptide is apparently synthesized by the ameba as suggested by [(35)S]-Cys and Met incorporation, probably as part of a larger molecule, from which it is cleaved by proteolysis. The full sequence was not found in the 431 available E. histolytica protein sequences. The factor may contribute to the unexpected paucity of the late inflammatory reaction found in advanced invasive amebiasis and, perhaps in consequence, to the regeneration without scarring (restitutio ad integrum) of the affected organs that is observed following successful treatment of this disease

  4. Effect of phosphatidylcholine-cholesterol liposomes on Entamoeba histolytica virulence.

    Science.gov (United States)

    Serrano-Luna, Jesús; Gutiérrez-Meza, Manuel; Mejía-Zepeda, Ricardo; Galindo-Gómez, Silvia; Tsutsumi, Víctor; Shibayama, Mineko

    2010-12-01

    Trophozoites of Entamoeba histolytica HM-1:IMSS become less virulent after long-term maintenance in axenic cultures. The factors responsible for the loss of virulence during in vitro cultivation remain unclear. However, it is known that in vitro cultivation of amoeba in culture medium supplemented with cholesterol restores their virulence. In this study, we analyzed the effect of adding phosphatidylcholine-cholesterol (PC-Chol) liposomes to the culture medium and evaluated the effect of this lipid on various biochemical and biological functions of E. histolytica HM-1:IMSS in terms of its virulence. The addition of PC-Chol liposomes to the culture medium maintained the virulence of these parasites against hamster liver at the same level as the original virulent E. histolytica strain, even though these amoebae were maintained without passage through hamster liver for 18 months. The trophozoites also showed increased endocytosis, erythrophagocytosis, and carbohydrate residue expression on the amoebic surface. Protease activities were also modified by the presence of cholesterol in the culture medium. These findings indicate the capacity of cholesterol to preserve amoeba virulence and provide an alternative method for the maintenance of virulent E. histolytica trophozoites without the need for in vivo procedures.

  5. Anti-inflammatory defense mechanisms of Entamoeba histolytica.

    Science.gov (United States)

    Silva-García, Raúl; Rico-Rosillo, Guadalupe

    2011-02-01

    The monocyte locomotion inhibitory factor (MLIF), a heat-stable oligopeptide found in the supernatant fluid of Entamoeba histolytica axenic cultures, may contribute to the delayed inflammation observed in amoebic hepatic abscess. This factor was isolated by ultra-filtration and high powered liquid chromatography, obtaining a primary Met-Gln-Cys-Asn-Ser structure, identified afterwards as the carboxyl-terminal (…Cys-Asn-Ser) active site. The selective anti-inflammatory effects of the pentapeptide have been observed in both in vitro and in vivo models, using a synthetic pentapeptide to maintain the same anti-inflammatory conditions during the experimental assays. Anti-inflammatory effects observed include inhibition of human monocyte locomotion and the respiratory burst in monocytes and neutrophils, increasing expression of anti-inflammatory cytokines and inhibiting expression of the adhesion molecules VLA-4 and VCAM, among others. In this review, we will describe the effects of MLIF detected so far and how it might be used as a therapeutical agent against inflammatory diseases.

  6. [Obtaining monoclonal antibodies against outer membrane glycoproteins of Entamoeba histolytica].

    Science.gov (United States)

    Agundis, C; Isibasi, A; Ortíz, V; Reyes, J L; Paniagua, J; Ramírez, A; Kumate, J

    1990-01-01

    The goal of this paper was the production of monoclonal antibodies capable of detecting relevant antigens from the surface of Entamoeba histolytica trophozoites, with the purpose of using them as a diagnostic test. The cellular fusion for obtaining the monoclonal antibodies (mAb) was done with spleen cells from BALB/c mice, previously immunized with glycoproteins from the membrane, as well as Sp2/0 cells. The hybridoma supernatants were tested with ELISA, using glycoproteins and lipopeptide phosphoglycans (LPPG) as antigens. Seven hybridomas producing mAb against the glycoproteins were found. Among these, three recognize LPPG. The ability of reacting with the mAb against two molecules disappeared for all the LPPG positive ones when were treated with meta-periodate, and only three reacted against the glycoproteins. All of the mAb were of the Ig M isotypes. They were characterized by Dot blot and Western blot assays. From the results, one may deduce that some mAb recognize as epitopes the polysaccharide portion, and thus infer that they are directed of against the surface and therefore, in the future, could be used with a diagnostic purpose.

  7. Entamoeba histolytica Trophozoites and Lipopeptidophosphoglycan Trigger Human Neutrophil Extracellular Traps

    Science.gov (United States)

    Ávila, Eva E.; Rodríguez, Mayra C.; Díaz-Godínez, César; Laclette, Juan P.; Becker, Ingeborg; Carrero, Julio C.

    2016-01-01

    Neutrophil defense mechanisms include phagocytosis, degranulation and the formation of extracellular traps (NET). These networks of DNA are triggered by several immune and microbial factors, representing a defense strategy to prevent microbial spread by trapping/killing pathogens. This may be important against Entamoeba histolytica, since its large size hinders its phagocytosis. The aim of this study was to determine whether E. histolytica and their lipopeptidophosphoglycan (EhLPPG) induce the formation of NETs and the outcome of their interaction with the parasite. Our data show that live amoebae and EhLPPG, but not fixed trophozoites, induced NET formation in a time and dose dependent manner, starting at 5 min of co-incubation. Although immunofluorescence studies showed that the NETs contain cathelicidin LL-37 in close proximity to amoebae, the trophozoite growth was only affected when ethylene glycol tetra-acetic acid (EGTA) was present during contact with NETs, suggesting that the activity of enzymes requiring calcium, such as DNases, may be important for amoeba survival. In conclusion, E. histolytica trophozoites and EhLPPG induce in vitro formation of human NETs, which did not affect the parasite growth unless a chelating agent was present. These results suggest that NETs may be an important factor of the innate immune response during infection with E. histolytica. PMID:27415627

  8. EVIDENCIA ULTRAESTRUCTURAL DEL NUCLÉOLO DE Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Citlali Vázquez-Echeverría

    2009-01-01

    Full Text Available Aunque la estructura celular de Entamoeba histolytica se conoce con detalle, no se ha descrito la presencia de material nucleolar con el microscopio electrónico. En este trabajo utilizamos técnicas citoquímicas para microscopía de luz y electrónica para evidenciar la presencia del nucléolo en trofozoitos de esta amiba. Con la técnica de azul de toluidina para RNA y la técnica de impregnación argéntica para organizador nucleolar, se observa contraste de material intranuclear periférico. Con el microscopio electrónico, un material similar de naturaleza fibro-granular se contrasta también con las técnicas para ribonucleoproteínas y para organizador nucleolar. Una zona similar es negativa cuando se aplican técnicas para DNA. Estos resultados muestran evidencia ultraestructural de la presencia de un nucléolo periférico y anular en el núcleo de E. histolytica. Se sugiere que este organelo intranuclear es un caracter general de los eucariontes.

  9. Investigating the mechanism of ADP-forming acetyl-CoA synthetase from the protozoan parasite Entamoeba histolytica.

    Science.gov (United States)

    Jones, Cheryl P; Khan, Kirin; Ingram-Smith, Cheryl

    2017-02-01

    ADP-forming acetyl-CoA synthetase (ACD) catalyzes the interconversion of acetyl-CoA and acetate. The related succinyl-CoA synthetase follows a three-step mechanism involving a single phosphoenzyme, but a novel four-step mechanism with two phosphoenzyme intermediates was proposed for Pyrococcus ACD. Characterization of enzyme variants of Entamoeba ACD in which the two proposed phosphorylated His residues were individually altered revealed that only His252 is essential for enzymatic activity. Analysis of variants altered at two residues proposed to interact with the phosphohistidine loop that swings between distinct parts of the active site are consistent with a mechanism involving a single phosphoenzyme intermediate. Our results suggest ACDs with different subunit structures may employ slightly different mechanisms to bridge the span between active sites I and II. © 2017 Federation of European Biochemical Societies.

  10. In silico analysis of ubiquitin/ubiquitin-like modifiers and their conjugating enzymes in Entamoeba species.

    Science.gov (United States)

    Arya, Shweta; Sharma, Gaurav; Gupta, Preeti; Tiwari, Swati

    2012-07-01

    Covalent modification of proteins by ubiquitin (Ub) and ubiquitin-like modifiers (Ubls) regulates many cellular functions in eukaryotes. These modifications are likely to be associated with pathogenesis, growth, and development of many protozoan parasites but molecular details about this pathway are unavailable for most protozoa. This study presents an analysis of the Ub pathway in three members of the Entamoeba species. Using bioinformatics tools we have identified all Ub and Ubl genes along with their corresponding activating, conjugating, and ligating enzymes (E1, E2s, and E3s) in three Entamoeba species, Entamoeba histolytica, Entamoeba dispar, and Entamoeba invadens. Phylogenetic trees were established for the identified E2s and RING finger E3s using maximum-likelihood method to infer the relationship among these proteins. In silico co-domain analysis of RING finger E3s implicates these proteins in a variety of functions. Several known and putative regulatory motifs were identified in the upstream regions of RING finger domain containing E3 genes. All E2 and E3 genes were analyzed in genomic context in E. histolytica and E. dispar. Most E2s and E3s were in syntenic positions in the two genomes. Association of these genes with transposable elements (TEs) was compared between E. histolytica and E. dispar. A closer association was found between RING finger E3s with TEs in E. histolytica. In summary, our analyses suggests that the complexity of the Ub pathway in Entamoeba species is close to that observed in higher eukaryotes. This study provides important data for further understanding the role of Ub pathway in the biology of these organisms.

  11. The Jacob2 lectin of the Entamoeba histolytica cyst wall binds chitin and is polymorphic.

    Directory of Open Access Journals (Sweden)

    Sudip K Ghosh

    2010-07-01

    Full Text Available The infectious and diagnostic form of Entamoeba histolytica (Eh, cause of amebic dysentery and liver abscess, is the quadranucleate cyst. The cyst wall of Entamoeba invadens (Ei, a model for Eh, is composed of chitin fibrils and three sets of chitin-binding lectins that cross-link chitin fibrils (multivalent Jacob lectins, self-aggregate (Jessie lectins, and remodel chitin (chitinase. The goal here was to determine how well the Ei model applies to Entamoeba cysts from humans.An Eh Jacob lectin (EhJacob2 has three predicted chitin-binding domains surrounding a large, Ser-rich spacer. Recombinant EhJacob2 made in transfected Eh trophozoites binds to particulate chitin. Sequences of PCR products using primers flanking the highly polymorphic spacer of EhJacob2 may be used to distinguish Entamoeba isolates. Antibodies to the EhJacob2, EhJessie3, and chitinase each recognize cyst walls of clinical isolates of Entamoeba. While numerous sera from patients with amebic intestinal infections and liver abscess recognize recombinant EhJacob1 and EhJessie3 lectins, few of these sera recognize recombinant EhJacob2.The EhJacob2 lectin binds chitin and is polymorphic, and Jacob2, Jessie3, and chitinase are present in cyst walls of clinical isolates of Entamoeba. These results suggest there are substantial similarities between cysts of the human pathogen (Eh and the in vitro model (Ei, even though there are quantitative and qualitative differences in their chitin-binding lectins.

  12. Diurnal Blood Pressure Rhythmicity in Relation to Environmental and Genetic Cues in Untreated Referred Patients.

    Science.gov (United States)

    Sheng, Chang-Sheng; Cheng, Yi-Bang; Wei, Fang-Fei; Yang, Wen-Yi; Guo, Qian-Hui; Li, Fei-Ka; Huang, Qi-Fang; Thijs, Lutgarde; Staessen, Jan A; Wang, Ji-Guang; Li, Yan

    2017-01-01

    No previous study has addressed the relative contributions of environmental and genetic cues to the diurnal blood pressure rhythmicity. From 24-hour ambulatory recordings of systolic blood pressure obtained in untreated patients (51% women; mean age, 51 years), we computed the night-to-day ratio in 897 and morning surge in 637. Environmental cues included season, mean daily outdoor temperature, atmospheric pressure, humidity and weekday, and the genetic cues 14 single nucleotide polymorphisms in 10 clock genes. Systolic blood pressure averaged (±SD) 126.7±11.9 mm Hg, night-to-day ratio 0.86±0.07, and morning surge 24.8±10.7 mm Hg. In adjusted analyses, night-to-day ratio was 2.4% higher in summer and 1.8% lower in winter (Penvironmental cues did not add to the night-to-day ratio or morning surge variance (P≥0.37). Among the 14 genetic variations, only CLOCK rs180260 was significantly associated with morning surge after adjustment for season, temperature, and other host factors and after Bonferroni correction (P=0.044). In CLOCK rs1801260 C allele carriers (n=83), morning surge was 3.7 mm Hg higher than in TT homozygotes (n=554). Of the night-to-day ratio and morning surge variance, season and temperature explained ≈8% and ≈3%, while for genetic cues, these proportions were ≈1% or less. In conclusion, environmental compared with genetic cues are substantially stronger drivers of the diurnal blood pressure rhythmicity. © 2016 American Heart Association, Inc.

  13. The genetics of water-use efficiency and its relation to growth in maritime pine

    Science.gov (United States)

    Marguerit, Elisa; Bouffier, Laurent; Chancerel, Emilie; Costa, Paolo; Lagane, Frédéric; Guehl, Jean-Marc; Plomion, Christophe; Brendel, Oliver

    2014-01-01

    To meet the increasing demand of wood biomass worldwide in the context of climate change, developing improved forest tree varieties for high productivity in water-limited conditions is becoming a major issue. This involves breeding for genotypes combining high growth and moderate water loss and thus high water-use efficiency (WUE). The present work provides original data about the genetics of intrinsic WUE (the ratio between net CO2 assimilation rate and stomatal conductance, also estimated by carbon isotope composition of plant material; δ13C) and its relation to growth in Pinus pinaster Ait. First, heritability for δ13C was estimated (0.29) using a 15-year-old progeny trial (Landes provenance), with no significant differences among three sites contrasting in water availability. High intersite correlations (0.63–0.91) and significant but low genotype–environment interactions were detected. Secondly, the genetic architectures of δ13C and growth were studied in a three-generation inbred pedigree, introducing the genetic background of a more-drought-adapted parent (Corsican provenance), at ages of 2 years (greenhouse) and 9 years (plantation). One of the quantitative trait loci (QTLs) identified in the field experiment, explaining 67% of the phenotypic variance, was also found among the QTLs detected in the greenhouse experiment, where it colocalized with QTLs for intrinsic WUE and stomatal conductance. This work was able to show that higher WUE was not genetically linked to less growth, allowing thus genetic improvement of water use. As far as is known, the heritability and QTL effects estimated here are based on the highest number of genotypes measured to date. PMID:24987014

  14. Ethical and clinical practice considerations for genetic counselors related to direct-to-consumer marketing of genetic tests.

    Science.gov (United States)

    Wade, Christopher H; Wilfond, Benjamin S

    2006-11-15

    Several companies utilize direct-to-consumer (DTC) advertising for genetic tests and some, but not all, bypass clinician involvement by offering DTC purchase of the tests. This article examines how DTC marketing strategies may affect genetic counselors, using available cardiovascular disease susceptibility tests as an illustration. The interpretation of these tests is complex and includes consideration of clinical validity and utility, and the further complications of gene-environment interactions and pleiotropy. Although it is unclear to what extent genetic counselors will encounter clients who have been exposed to DTC marketing strategies, these strategies may influence genetic counseling interactions if they produce directed interest in specific tests and unrealistic expectations for the tests' capacity to predict disease. Often, a client's concern about risk for cardiovascular diseases is best addressed by established clinical tests and a family history assessment. Ethical dilemmas may arise for genetic counselors who consider whether to accept clients who request test interpretation or to order DTC-advertised tests that require a clinician's authorization. Genetic counselors' obligations to care for clients extend to interpreting DTC tests, although this obligation may be fulfilled by referral or consultation with specialists. Genetic counselors do not have an obligation to order DTC-advertised tests that have minimal clinical validity and utility at a client's request. This can be a justified restriction on autonomy based on consideration of risks to the client, the costs, and the implications for society.

  15. Genetics of kidney disease and related cardiometabolic phenotypes in Zuni Indians: The Zuni Kidney Project

    Directory of Open Access Journals (Sweden)

    Sandra L Laston

    2015-01-01

    Full Text Available The objective of this study is to identify genetic factors associated with chronic kidney disease (CKD and related cardiometabolic phenotypes among participants of the Genetics of Kidney Disease in Zuni Indians study. The study was conducted as a community-based participatory research project in the Zuni Indians, a small endogamous tribe in rural New Mexico. We recruited 998 members from 28 extended multigenerational families, ascertained through probands with CKD who had at least one sibling with CKD. We used the Illumina Infinium Human1M-Duo v3.0 BeadChips to type 1.1 million single nucleotide polymorphisms (SNPs. Prevalence estimates for CKD, hyperuricemia, diabetes and hypertension were 24%, 30%, 17% and 34%, respectively. We found a significant (p<1.58 × 10-7 association for a SNP in a novel gene for serum creatinine (PTPLAD2. We replicated significant associations for genes with serum uric acid (SLC2A9, triglyceride levels (APOA1, BUD13, ZNF259, and total cholesterol (PVRL2. We found novel suggestive associations (p<1.58 × 10-6 for SNPs in genes with systolic (OLFML2B, and diastolic blood pressure (NFIA. We identified a series of genes associated with CKD and related cardiometabolic phenotypes among Zuni Indians, a population with a high prevalence of kidney disease. Illuminating genetic variations that modulate the risk for these disorders may ultimately provide a basis for novel preventive strategies and therapeutic interventions.

  16. Genetic dyslexia risk variant is related to neural connectivity patterns underlying phonological awareness in children.

    Science.gov (United States)

    Skeide, Michael A; Kirsten, Holger; Kraft, Indra; Schaadt, Gesa; Müller, Bent; Neef, Nicole; Brauer, Jens; Wilcke, Arndt; Emmrich, Frank; Boltze, Johannes; Friederici, Angela D

    2015-09-01

    Phonological awareness is the best-validated predictor of reading and spelling skill and therefore highly relevant for developmental dyslexia. Prior imaging genetics studies link several dyslexia risk genes to either brain-functional or brain-structural factors of phonological deficits. However, coherent evidence for genetic associations with both functional and structural neural phenotypes underlying variation in phonological awareness has not yet been provided. Here we demonstrate that rs11100040, a reported modifier of SLC2A3, is related to the functional connectivity of left fronto-temporal phonological processing areas at resting state in a sample of 9- to 12-year-old children. Furthermore, we provide evidence that rs11100040 is related to the fractional anisotropy of the arcuate fasciculus, which forms the structural connection between these areas. This structural connectivity phenotype is associated with phonological awareness, which is in turn associated with the individual retrospective risk scores in an early dyslexia screening as well as to spelling. These results suggest a link between a dyslexia risk genotype and a functional as well as a structural neural phenotype, which is associated with a phonological awareness phenotype. The present study goes beyond previous work by integrating genetic, brain-functional and brain-structural aspects of phonological awareness within a single approach. These combined findings might be another step towards a multimodal biomarker for developmental dyslexia.

  17. Genetic and environmental overlap between Chinese and English reading-related skills in Chinese children.

    Science.gov (United States)

    Wong, Simpson W L; Chow, Bonnie Wing-Yin; Ho, Connie Suk-Han; Waye, Mary M Y; Bishop, Dorothy V M

    2014-11-01

    This twin study examined the relative contributions of genes and environment on 2nd language reading acquisition of Chinese-speaking children learning English. We examined whether specific skills-visual word recognition, receptive vocabulary, phonological awareness, phonological memory, and speech discrimination-in the 1st and 2nd languages have distinct or overlapping genetic and environmental origins. A sample of 279 Chinese twin pairs with a mean age of 6 years was tested. Univariate twin analyses were used to identify sources of individual variations in reading abilities and related cognitive-linguistic skills in Chinese and English, respectively. They were used to show both similar and distinctive patterns in these skills across Chinese and English. Bivariate Cholesky decomposition analyses indicated genetic overlaps between all parallel Chinese and English variables, as well as shared environmental overlaps in receptive vocabulary and phonological awareness. The phenotypic correlations between 1st and 2nd language skills previously observed in cross-linguistic studies could be explained by the shared genetic and environmental influences found in this twin study. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  18. Associations between an obesity related genetic variant (FTO rs9939609) and prostate cancer risk.

    Science.gov (United States)

    Lewis, Sarah J; Murad, Ali; Chen, Lina; Davey Smith, George; Donovan, Jenny; Palmer, Tom; Hamdy, Freddie; Neal, David; Lane, J Athene; Davis, Michael; Cox, Angela; Martin, Richard M

    2010-10-19

    Observational studies suggest that obese men have a lower risk of incident prostate cancer, but an increased risk of advanced and fatal cancers. These observations could be due to confounding, detection bias, or a biological effect of obesity. Genetic studies are less susceptible to confounding than observational epidemiology and can suggest how associations between phenotypes (such as obesity) and diseases arise. To determine whether the associations between obesity and prostate cancer are causal, we conducted a genetic association study of the relationship between a single nucleotide polymorphism known to be associated with obesity (FTO rs9939609) and prostate cancer. Data are from a population-based sample of 1550 screen-detected prostate cancers, 1815 age- and general practice matched controls with unrestricted prostate specific antigen (PSA) values and 1175 low-PSA controls (PSA prostate cancer risk, but positively associated with high-grade cancer among cases (OR high- versus low-grade cancer  = 1.16; 0.99-1.37 p = 0.07 per allele). Although evidence for these effects was weak, they are consistent with observational data based on BMI phenotypes and suggest that the observed association between obesity and prostate cancer is not due to confounding. Further research should confirm these findings, extend them to other BMI-related genetic variants and determine whether they are due to detection bias or obesity-related hormonal changes. Controlled-Trials.com ISRCTN20141297.

  19. Recent advances in Entamoeba biology: RNA interference, drug discovery, and gut microbiome

    Science.gov (United States)

    Singh, Upinder

    2016-01-01

    In recent years, substantial progress has been made in understanding the molecular and cell biology of the human parasite Entamoeba histolytica, an important pathogen with significant global impact. This review outlines some recent advances in the Entamoeba field in the last five years, focusing on areas that have not recently been discussed in detail: (i) molecular mechanisms regulating parasite gene expression, (ii) new efforts at drug discovery using high-throughput drug screens, and (iii) the effect of gut microbiota on amoebiasis. PMID:27853522

  20. A PCR-RFLP method for the simultaneous differentiation of three Entamoeba species.

    Science.gov (United States)

    Fontecha, Gustavo A; García, Kimberly; Rueda, María Mercedes; Sosa-Ochoa, Wilfredo; Sánchez, Ana Lourdes; Leiva, Byron

    2015-01-01

    Amoebiasis caused by Entamoeba histolytica continues to be one of the most common parasitic diseases in the developing world. Despite its relevance, due to the lack of accurate diagnostic methods, the true clinical and public health importance of this parasite remains uncertain. The aim of this study was to develop a new diagnostic tool to differentiate E.histolytica from the morphologically undistinguishable E.dispar and E.moshkovskii. We developed a specific, fast and simple PCR-RFLP method that was able to accurately differentiate experimentally-obtained restriction patterns from the three Entamoeba species. This new method could prove useful for clinical and epidemiological purposes.

  1. Genetics and age-related macular degeneration: a practical review for the clinician

    Directory of Open Access Journals (Sweden)

    Schwartz SG

    2016-07-01

    Full Text Available Stephen G Schwartz,1 Blake M Hampton,1 Jaclyn L Kovach,1 Milam A Brantley Jr2 1Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; 2Department of Ophthalmology, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA Abstract: Age-related macular degeneration is a complex disease, with both genetic and environmental risk factors interacting in unknown ways. Currently, 52 gene variants within 34 loci have been significantly associated with age-related macular degeneration. Two well-studied major genes are complement factor H (CFH and age-related maculopathy susceptibility 2 (ARMS2. There exist several commercially available tests that are proposed to stratify patients into high-risk and low-risk groups, as well as predict response to nutritional supplementation. However, at present, the bulk of the available peer-reviewed evidence suggests that genetic testing is more useful as a research tool than for clinical management of patients. Keywords: age-related macular degeneration, age-related maculopathy susceptibility 2, ARMS2, complement factor H, CFH, pharmacogenetics, vascular endothelial growth factor

  2. Field of Genes: An Investigation of Sports-Related Genetic Testing

    Science.gov (United States)

    Wagner, Jennifer K.; Royal, Charmaine D.

    2012-01-01

    Sports-related genetic testing is a sector of the diverse direct-to-consumer (DTC) industry that has not yet been examined thoroughly by academic scholars. A systematic search was used to identify companies in this sector and content analysis of online information was performed. More than a dozen companies were identified. Marketing practices observed generally did not target parents for child testing, and marketing images were mild compared to images used in popular media. Information was provided at a high reading level (industry-wide Flesh-Kincaid Grade Levels > 11). While ~75% of companies provide privacy policies and terms of service prior to purchase and ~40% provide scientific citations for their tests, e-commerce generally may adequately protect DTC genetics consumers without new federal legislation or regulation. PMID:25562204

  3. Identifying flavor preference subgroups. Genetic basis and related eating behavior traits.

    Science.gov (United States)

    Törnwall, Outi; Silventoinen, Karri; Hiekkalinna, Tero; Perola, Markus; Tuorila, Hely; Kaprio, Jaakko

    2014-04-01

    Subgroups based on flavor preferences were identified and their genetic and behavior related characteristics investigated using extensive data from 331 Finnish twins (21-25years, 146 men) including 47 monozygotic (MZ) and 93 dizygotic (DZ) pairs, and 51 twin individuals. The subgroup identification (hierarchical and K-means clustering) was based on liking responses to food names representing sour, umami, and spicy flavor qualities. Furthermore, sensory tests were conducted, a questionnaire on food likes completed, and various eating behavior related traits measured with validated scales. Sensory data included intensity ratings of PROP (6-n-propylthiouracil-impregnated filter paper), hedonic and intensity responses to sourness (orange juice with and without added citric acid, 0.42%), pungency (strawberry jelly with and without added capsaicin 0.00013%) and umami ('mouthfeel flavor' taste solution). Ratings of liking of 41 general food names were categorized into salty-and-fatty, sweet-and-fatty, fruits and vegetables and fish foods. Subgroup differences (complex samples procedure) and the genetics underlying the subgroups (structural equation modeling) were investigated. Of the resulting two groups (basic, n=140, adventurous n=152; non-grouped n=39), the adventurous expressed higher liking for sour and spicy foods, and had more tolerance for capsaicin burn in the sensory-hedonic test. The adventurous were also less food neophobic (25.9±9.1 vs. 32.5±10.6, respectively) and expressed higher liking for fruits and vegetables compared to the basic group. Genetic effects were shown to underlie the subgroups (heritability 72%, CI: 36-92%). Linkage analysis for 27 candidate gene regions revealed suggestively that being adventurous is linked to TAS1R1 and PKD1L3 genes. These results indicate that food neophobia and genetic differences may form a barrier through which individual flavor preferences are generated.

  4. Genetic Variants Related to Longer Telomere Length are Associated with Increased Risk of Renal Cell Carcinoma.

    Science.gov (United States)

    Machiela, Mitchell J; Hofmann, Jonathan N; Carreras-Torres, Robert; Brown, Kevin M; Johansson, Mattias; Wang, Zhaoming; Foll, Matthieu; Li, Peng; Rothman, Nathaniel; Savage, Sharon A; Gaborieau, Valerie; McKay, James D; Ye, Yuanqing; Henrion, Marc; Bruinsma, Fiona; Jordan, Susan; Severi, Gianluca; Hveem, Kristian; Vatten, Lars J; Fletcher, Tony; Koppova, Kvetoslava; Larsson, Susanna C; Wolk, Alicja; Banks, Rosamonde E; Selby, Peter J; Easton, Douglas F; Pharoah, Paul; Andreotti, Gabriella; Freeman, Laura E Beane; Koutros, Stella; Albanes, Demetrius; Mannisto, Satu; Weinstein, Stephanie; Clark, Peter E; Edwards, Todd E; Lipworth, Loren; Gapstur, Susan M; Stevens, Victoria L; Carol, Hallie; Freedman, Matthew L; Pomerantz, Mark M; Cho, Eunyoung; Kraft, Peter; Preston, Mark A; Wilson, Kathryn M; Gaziano, J Michael; Sesso, Howard S; Black, Amanda; Freedman, Neal D; Huang, Wen-Yi; Anema, John G; Kahnoski, Richard J; Lane, Brian R; Noyes, Sabrina L; Petillo, David; Colli, Leandro M; Sampson, Joshua N; Besse, Celine; Blanche, Helene; Boland, Anne; Burdette, Laurie; Prokhortchouk, Egor; Skryabin, Konstantin G; Yeager, Meredith; Mijuskovic, Mirjana; Ognjanovic, Miodrag; Foretova, Lenka; Holcatova, Ivana; Janout, Vladimir; Mates, Dana; Mukeriya, Anush; Rascu, Stefan; Zaridze, David; Bencko, Vladimir; Cybulski, Cezary; Fabianova, Eleonora; Jinga, Viorel; Lissowska, Jolanta; Lubinski, Jan; Navratilova, Marie; Rudnai, Peter; Szeszenia-Dabrowska, Neonila; Benhamou, Simone; Cancel-Tassin, Geraldine; Cussenot, Olivier; Bueno-de-Mesquita, H Bas; Canzian, Federico; Duell, Eric J; Ljungberg, Börje; Sitaram, Raviprakash T; Peters, Ulrike; White, Emily; Anderson, Garnet L; Johnson, Lisa; Luo, Juhua; Buring, Julie; Lee, I-Min; Chow, Wong-Ho; Moore, Lee E; Wood, Christopher; Eisen, Timothy; Larkin, James; Choueiri, Toni K; Lathrop, G Mark; Teh, Bin Tean; Deleuze, Jean-Francois; Wu, Xifeng; Houlston, Richard S; Brennan, Paul; Chanock, Stephen J; Scelo, Ghislaine; Purdue, Mark P

    2017-08-07

    Relative telomere length in peripheral blood leukocytes has been evaluated as a potential biomarker for renal cell carcinoma (RCC) risk in several studies, with conflicting findings. We performed an analysis of genetic variants associated with leukocyte telomere length to assess the relationship between telomere length and RCC risk using Mendelian randomization, an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations. Genotypes from nine telomere length-associated variants for 10 784 cases and 20 406 cancer-free controls from six genome-wide association studies (GWAS) of RCC were aggregated into a weighted genetic risk score (GRS) predictive of leukocyte telomere length. Odds ratios (ORs) relating the GRS and RCC risk were computed in individual GWAS datasets and combined by meta-analysis. Longer genetically inferred telomere length was associated with an increased risk of RCC (OR=2.07 per predicted kilobase increase, 95% confidence interval [CI]:=1.70-2.53, p0.5) with GWAS-identified RCC risk variants (rs10936599 and rs9420907) from the telomere length GRS; despite this exclusion, a statistically significant association between the GRS and RCC risk persisted (OR=1.73, 95% CI=1.36-2.21, pbody of evidence indicating some aspect of longer telomere length is important for RCC risk. Telomeres are segments of DNA at chromosome ends that maintain chromosomal stability. Our study investigated the relationship between genetic variants associated with telomere length and renal cell carcinoma risk. We found evidence suggesting individuals with inherited predisposition to longer telomere length are at increased risk of developing renal cell carcinoma. Published by Elsevier B.V.

  5. Genetic polymorphisms in folate pathway enzymes, DRD4 and GSTM1 are related to temporomandibular disorder

    Directory of Open Access Journals (Sweden)

    Mayor-Olea Alvaro

    2011-05-01

    Full Text Available Abstract Background Temporomandibular disorder (TMD is a multifactorial syndrome related to a critical period of human life. TMD has been associated with psychological dysfunctions, oxidative state and sexual dimorphism with coincidental occurrence along the pubertal development. In this work we study the association between TMD and genetic polymorphisms of folate metabolism, neurotransmission, oxidative and hormonal metabolism. Folate metabolism, which depends on genes variations and diet, is directly involved in genetic and epigenetic variations that can influence the changes of last growing period of development in human and the appearance of the TMD. Methods A case-control study was designed to evaluate the impact of genetic polymorphisms above described on TMD. A total of 229 individuals (69% women were included at the study; 86 were patients with TMD and 143 were healthy control subjects. Subjects underwent to a clinical examination following the guidelines by the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD. Genotyping of 20 Single Nucleotide Polymorphisms (SNPs, divided in two groups, was performed by multiplex minisequencing preceded by multiplex PCR. Other seven genetic polymorphisms different from SNPs (deletions, insertions, tandem repeat, null genotype were achieved by a multiplex-PCR. A chi-square test was performed to determine the differences in genotype and allelic frequencies between TMD patients and healthy subjects. To estimate TMD risk, in those polymorphisms that shown significant differences, odds ratio (OR with a 95% of confidence interval were calculated. Results Six of the polymorphisms showed statistical associations with TMD. Four of them are related to enzymes of folates metabolism: Allele G of Serine Hydoxymethyltransferase 1 (SHMT1 rs1979277 (OR = 3.99; 95%CI 1.72, 9.25; p = 0.002, allele G of SHMT1 rs638416 (OR = 2.80; 95%CI 1.51, 5.21; p = 0.013, allele T of Methylentetrahydrofolate

  6. Growth of the protozoan parasite Entamoeba histolytica in 5-azacytidine has limited effects on parasite gene expression

    Directory of Open Access Journals (Sweden)

    Hackney Jason A

    2007-01-01

    Full Text Available Abstract Background In higher eukaryotes DNA methylation regulates important biological functions including silencing of gene expression and protection from adverse effects of retrotransposons. In the protozoan parasite Entamoeba histolytica, a DNA methyltransferase has been identified and treatment with 5-azacytidine (5-AzaC, a potent inhibitor of DNA methyltransferase, has been reported to attenuate parasite virulence. However, the overall extent of DNA methylation and its subsequent effects on global gene expression in this parasite are currently unknown. Results In order to identify the genome-wide effects of DNA methylation in E. histolytica, we used a short oligonucleotide microarray representing 9,435 genes (~95% of all annotated amebic genes and compared the expression profile of E. histolytica HM-1:IMSS parasites with those treated with 23 μM 5-AzaC for up to one week. Overall, 2.1% of genes tested were transcriptionally modulated under these conditions. 68 genes were upregulated and 131 genes down regulated (2-fold change; p-value E. histolytica: (i genes that were endogenously silenced by genomic DNA methylation and for which 5-AzaC treatment induced transcriptional de-repression, and (ii genes that have genomic DNA methylation, but which were not endogenously silenced by the methylation. We identified among the genes down regulated by 5-AzaC treatment a cysteine proteinase (2.m00545 and lysozyme (52.m00148 both of which have known roles in amebic pathogenesis. Decreased expression of these genes in the 5-AzaC treated E. histolytica may account in part for the parasites reduced cytolytic abilities. Conclusion This work represents the first genome-wide analysis of DNA-methylation in Entamoeba histolytica and indicates that DNA methylation has relatively limited effects on gene expression in this parasite.

  7. A Discussion on Possible Indicators Related to Genetic Structure Changes in Plant Germplasm Conservation

    Institute of Scientific and Technical Information of China (English)

    GAI Jun-yi

    2004-01-01

    The purpose of the present paper is to study and develop indicators and procedures for the evaluation of genetic structure changes in germplasm conservation due to social and natural environment reasons.Some basic concepts in germplasm study were introduced at first. Then, six kinds of indicators for genetic diversity as a measure of genetic potential of a germplasm collection were presented, i.e.,numbers of different entities at certain level, evenness of the entity distribution, genetic similarityand genetic distance, genetic variance and genetic coefficient of variation, multivariate genetic variation indices, and coefficient of parentage. It was pointed out that genetic dispersion did not provide a complete concept of genetic diversity if without any information from genetic richness. Based on the above, the indicators for genetic erosion as the genetic structure changes of germplasm conservation due to social reasons, the indicators of genetic vulnerability as the genetic structure changes of germplasm conservation due to environmental stresses, the measurement of genetic drift and genetic shift as the genetic structure changes of germplasm collection during reproduction or seed increase were reviewed and developed. Furthermore, the estimation procedures of the indicators by using molecular markers were suggested. Finally, the case studies on suitable conservation sample size of self-pollinated and open-pollinated populations were given for reference.

  8. Uniform Variation in Genetic-Traits of a Marine Bivalve Related to Starvation, Pollution and Geographic Clines

    NARCIS (Netherlands)

    Hummel, H.; Bogaards, R.H.; Amiard-Triquet, C.; Bachelet, G.; Desprez, M.; Marchand, J.; Rybarczyk, H.; Sylvand, B.; De Wit, Y.; De Wolf, L.

    1995-01-01

    Consistent patterns of genetic variation in the marine bivalve Macoma balthica (L.) were found after exposure to low levels of copper, starvation, and along geographic dines. The geographic dines were related to temperature and salinity. Genetic differences were primarily found in the LAP (Leucine a

  9. Effect of test duration and feeding on relative sensitivity of genetically distinct clades of Hyalella azteca.

    Science.gov (United States)

    Soucek, David J; Dickinson, Amy; Major, Kaley M; McEwen, Abigail R

    2013-11-01

    The amphipod Hyalella azteca is widely used in ecotoxicology laboratories for the assessment of chemical risks to aquatic environments, and it is a cryptic species complex with a number of genetically distinct strains found in wild populations. While it would be valuable to note differences in contaminant sensitivity among different strains collected from various field sites, those findings would be influenced by acclimation of the populations to local conditions. In addition, potential differences in metabolism or lipid storage among different strains may confound assessment of sensitivity in unfed acute toxicity tests. In the present study, our aim was to assess whether there are genetic differences in contaminant sensitivity among three cryptic provisional species of H. azteca. Therefore, we used organisms cultured under the same conditions, assessed their ability to survive for extended periods without food, and conducted fed and unfed acute toxicity tests with two anions (nitrate and chloride) whose toxicities are not expected to be altered by the addition of food. We found that the three genetically distinct clades of H. azteca had substantially different responses to starvation, and the presence/absence of food during acute toxicity tests had a strong role in determining the relative sensitivity of the three clades. In fed tests, where starvation was no longer a potential stressor, significant differences in sensitivity were still observed among the three clades. In light of these differences in sensitivity, we suggest that ecotoxicology laboratories consider using a provisional species in toxicity tests that is a regionally appropriate surrogate.

  10. The genetics of age-related macular degeneration (AMD)--Novel targets for designing treatment options?

    Science.gov (United States)

    Grassmann, Felix; Fauser, Sascha; Weber, Bernhard H F

    2015-09-01

    Age-related macular degeneration (AMD) is a progressive disease of the central retina and the main cause of legal blindness in industrialized countries. Risk to develop the disease is conferred by both individual as well as genetic factors with the latter being increasingly deciphered over the last decade. Therapeutically, striking advances have been made for the treatment of the neovascular form of late stage AMD while for the late stage atrophic form of the disease, which accounts for almost half of the visually impaired, there is currently no effective therapy on the market. This review highlights our current knowledge on the genetic architecture of early and late stage AMD and explores its potential for the discovery of novel, target-guided treatment options. We reflect on current clinical and experimental therapies for all forms of AMD and specifically note a persisting lack of efficacy for treatment in atrophic AMD. We further explore the current insight in AMD-associated genes and pathways and critically question whether this knowledge is suited to design novel treatment options. Specifically, we point out that known genetic factors associated with AMD govern the risk to develop disease and thus may not play a role in its severity or progression. Treatments based on such knowledge appear appropriate rather for prevention than treatment of manifest disease. As a consequence, future research in AMD needs to be greatly focused on approaches relevant to the patients and their medical needs.

  11. THE STUDY OF POPULATION GENETIC RELATION AMONG TEN ETHNIC GROUPS IN NORTHWEST CHINA

    Institute of Scientific and Technical Information of China (English)

    康龙丽; 金天博; 陈腾; 李生斌

    2004-01-01

    Objective To investigate the genetic relation among ten ethnic groups in northwest China. Methods Allele frequencies of six STR(short tandem repeat ) loci in D13S1358, VWA, FGA, D5S818, D13S317, and D7S820 were collected from Lasa Tibetan, Changdu Tibetan, Xian Han, Gansu Dongxiang, Gansu Yugu, Xinjiang Uygur, Ozbak, Kirgiz, Sibe, Ningxia Hui by the results of State Key laboratory, Forensic Science Department, school of medical, Xian Jiaotong University and internet biological information data bank, and compared with that of the Mongolian, Zhuang in China, and White and Negro in USA. The polymorphism index (H, DP, PPE, PIC) and genetic distance, then the phylogenetic tree of all population were reported. Results The resulting tree topology exhibited strong geographic and racial partitioning consistent with that obtained with HLA and classical genetic polymorphisms. Conclusion The results suggest that forensic STR loci may be particularly powerful tools and provide the necessary fine resolution for the reconstruction of recent human evolutionary history.

  12. Prevalence of amoebiasis in a model research community and its confirmation using stool antigen elisa for Entamoeba histolytica.

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    Akhtar, Tasleem; Khan, Aamir Ghafoor; Ahmed, Israr; Nazli, Rubina; Haider, Jamila

    2016-09-01

    Entamoeba histolytica (E. histolytica) produces an invasive disease called amoebiasis, which commonly produces diarrhea with or without blood in both children and adults, leading to high morbidity and mortality. Entamoeba dispar (E. Dispar) is a non invasive, non pathogenic organism. Both Entamoeba histolytica and Entamoeba Dispar look alike on microscopy and therefore cannot be differentiated unless checked on ELISA, PCR or other specific method. To calculate the actual prevalence of pathogenic amoebiasis in children by comparing the stool microscopy with ELISA stool antigen i.e. gold standard. Across sectional, comparative study. Children under five years in a community village Budhni, District Peshawar. A sample of 288 children aged Entamoeba histolytica. The specificity and sensitivity of microscopic method was calculated against ELISA. Data was analyzed using statistical computer software package SPSS version 10.0. A total of 288 stool specimens were collected and examined for Entamoeba histolytica. Out of these 36(12.5%) stools were positive for E. histolyticaon microscopy while 14(4.9%) were positive on ELISA. Out of 14 ELISA positive samples, 10 samples were also positive on microscopy while 4 were ELISA positive but microscopy negative. About 22 samples, which were positive on microscopy were negative on ELISA indicating that these samples might have been of E. Dispar which is non pathogenic protozoa. The sensitivity and specificity of microscopic method was 71.4% and 90.5% respectively, as against stool antigen test. Actual prevalence of Entamoeba histolytica is low in the area. Stool ELISA was able to differentiate between pathogenic Entamoeba histolytica and the non-pathogenic Entamoeba dispar and thus can minimize unnecessary antiamoebic treatment in these children.

  13. Genetic Variation in Autophagy-Related Genes Influences the Risk and Phenotype of Buruli Ulcer.

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    Carlos Capela

    2016-04-01

    Full Text Available Buruli ulcer (BU is a severe necrotizing human skin disease caused by Mycobacterium ulcerans. Clinically, presentation is a sum of these diverse pathogenic hits subjected to critical immune-regulatory mechanisms. Among them, autophagy has been demonstrated as a cellular process of critical importance. Since microtubules and dynein are affected by mycolactone, the critical pathogenic exotoxin produced by M. ulcerans, cytoskeleton-related changes might potentially impair the autophagic process and impact the risk and progression of infection.Genetic variants in the autophagy-related genes NOD2, PARK2 and ATG16L1 has been associated with susceptibility to mycobacterial diseases. Here, we investigated their association with BU risk, its severe phenotypes and its progression to an ulcerative form.Genetic variants were genotyped using KASPar chemistry in 208 BU patients (70.2% with an ulcerative form and 28% in severe WHO category 3 phenotype and 300 healthy endemic controls.The rs1333955 SNP in PARK2 was significantly associated with increased susceptibility to BU [odds ratio (OR, 1.43; P = 0.05]. In addition, both the rs9302752 and rs2066842 SNPs in NOD2 gee significantly increased the predisposition of patients to develop category 3 (OR, 2.23; P = 0.02; and OR 12.7; P = 0.03, respectively, whereas the rs2241880 SNP in ATG16L1 was found to significantly protect patients from presenting the ulcer phenotype (OR, 0.35; P = 0.02.Our findings indicate that specific genetic variants in autophagy-related genes influence susceptibility to the development of BU and its progression to severe phenotypes.

  14. Proteomic analysis of the cyst stage of Entamoeba histolytica.

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    Ibne Karim M Ali

    Full Text Available The category B agent of bioterrorism, Entamoeba histolytica has a two-stage life cycle: an infective cyst stage, and an invasive trophozoite stage. Due to our inability to effectively induce encystation in vitro, our knowledge about the cyst form remains limited. This also hampers our ability to develop cyst-specific diagnostic tools.Three main aims were (i to identify E. histolytica proteins in cyst samples, (ii to enrich our knowledge about the cyst stage, and (iii to identify candidate proteins to develop cyst-specific diagnostic tools.Cysts were purified from the stool of infected individuals using Percoll (gradient purification. A highly sensitive LC-MS/MS mass spectrometer (Orbitrap was used to identify cyst proteins.A total of 417 non-redundant E. histolytica proteins were identified including 195 proteins that were never detected in trophozoite-derived proteomes or expressed sequence tag (EST datasets, consistent with cyst specificity. Cyst-wall specific glycoproteins Jacob, Jessie and chitinase were positively identified. Antibodies produced against Jacob identified cysts in fecal specimens and have potential utility as a diagnostic reagent. Several protein kinases, small GTPase signaling molecules, DNA repair proteins, epigenetic regulators, and surface associated proteins were also identified. Proteins we identified are likely to be among the most abundant in excreted cysts, and therefore show promise as diagnostic targets.The proteome data generated here are a first for naturally-occurring E. histolytica cysts, and they provide important insights into the infectious cyst form. Additionally, numerous unique candidate proteins were identified which will aid the development of new diagnostic tools for identification of E. histolytica cysts.

  15. Heat Shock Protein 90 Inhibitors repurposed against Entamoeba histolytica

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    Dea eShahinas

    2015-04-01

    Full Text Available Hsp90 is an essential chaperone responsible for trafficking a vast array of client proteins, which are substrates that Hsp90 regulates in eukaryotic cells under stress conditions. The ATP-binding N-terminal domain of Hsp90 (also known as a GHKL type ATPase domain can serve as a specific drug target, because sufficient structural diversity in the ATP-binding pocket of Hsp90 allows for ortholog selectivity of Hsp90 inhibitors. The primary objective of this study is to identify inhibitors specific for the ATP-binding domain of Entamoeba histolytica Hsp90 (EhHsp90. An additional aim, using a combination of site-directed mutagenesis and a protein in vitro assay, is to show that the antiparasitic activity of Hsp90 inhibitors is dependent on specific residues within the ATP-binding domain. Here, we tested the activity of 43 inhibitors of Hsp90 that we previously identified using a high-throughput screen. Of the 43 compounds tested, 19 competed for binding of the EhHsp90 ATP-binding domain. Five out of the 19 EhHsp90 protein hits demonstrated activity against E. histolytica in vitro culture: rifabutin, rutilantin, cetylpyridinium chloride, pararosaniline pamoate and gentian violet. These 5 top E. histolytica Hsp90 inhibitors showed 30-100% inhibition of E. histolytica in culture in the micromolar range. These data suggest that E. histolytica-specific Hsp90 inhibitors are possible to identify and provide important lead compounds for the development of novel antiamebic drugs.

  16. Proteomic Analysis of the Cyst Stage of Entamoeba histolytica

    Science.gov (United States)

    Ali, Ibne Karim M.; Haque, Rashidul; Siddique, Abdullah; Kabir, Mamun; Sherman, Nicholas E.; Gray, Sean A.; Cangelosi, Gerard A.; Petri, William A.

    2012-01-01

    Background The category B agent of bioterrorism, Entamoeba histolytica has a two-stage life cycle: an infective cyst stage, and an invasive trophozoite stage. Due to our inability to effectively induce encystation in vitro, our knowledge about the cyst form remains limited. This also hampers our ability to develop cyst-specific diagnostic tools. Aims Three main aims were (i) to identify E. histolytica proteins in cyst samples, (ii) to enrich our knowledge about the cyst stage, and (iii) to identify candidate proteins to develop cyst-specific diagnostic tools. Methods Cysts were purified from the stool of infected individuals using Percoll (gradient) purification. A highly sensitive LC-MS/MS mass spectrometer (Orbitrap) was used to identify cyst proteins. Results A total of 417 non-redundant E. histolytica proteins were identified including 195 proteins that were never detected in trophozoite-derived proteomes or expressed sequence tag (EST) datasets, consistent with cyst specificity. Cyst-wall specific glycoproteins Jacob, Jessie and chitinase were positively identified. Antibodies produced against Jacob identified cysts in fecal specimens and have potential utility as a diagnostic reagent. Several protein kinases, small GTPase signaling molecules, DNA repair proteins, epigenetic regulators, and surface associated proteins were also identified. Proteins we identified are likely to be among the most abundant in excreted cysts, and therefore show promise as diagnostic targets. Major Conclusions The proteome data generated here are a first for naturally-occurring E. histolytica cysts, and they provide important insights into the infectious cyst form. Additionally, numerous unique candidate proteins were identified which will aid the development of new diagnostic tools for identification of E. histolytica cysts. PMID:22590659

  17. Characterization of the protein tyrosine phosphatase PRL from Entamoeba histolytica.

    Science.gov (United States)

    Ramírez-Tapia, Ana Lilia; Baylón-Pacheco, Lidia; Espíritu-Gordillo, Patricia; Rosales-Encina, José Luis

    2015-12-01

    Protein tyrosine phosphatase of regenerating liver (PRL) is a group of phosphatases that has not been broadly studied in protozoan parasites. In humans, PRLs are involved in metastatic cancer, the promotion of cell migration and invasion. PTPs have been increasingly recognized as important effectors of host-pathogen interactions. We characterized the only putative protein tyrosine phosphatase PRL (PTP EhPRL) in the eukaryotic human intestinal parasite Entamoeba histolytica. Here, we reported that the EhPRL protein possessed the classical HCX5R catalytic motif of PTPs and the CAAX box characteristic of the PRL family and exhibited 31-32% homology with the three human PRL isoforms. In amebae, the protein was expressed at low but detectable levels. The recombinant protein (rEhPRL) had enzymatic activity with the 3-o-methyl fluorescein phosphate (OMFP) substrate; this enzymatic activity was inhibited by the PTP inhibitor o-vanadate. Using immunofluorescence we showed that native EhPRL was localized to the cytoplasm and plasma membrane. When the trophozoites interacted with collagen, EhPRL relocalized over time to vesicle-like structures. Interaction with fibronectin increased the presence of the enzyme in the cytoplasm. Using RT-PCR, we demonstrated that EhPRL mRNA expression was upregulated when the trophozoites interacted with collagen but not with fibronectin. Trophozoites recovered from amoebic liver abscesses showed higher EhPRL mRNA expression levels than normal trophozoites. These results strongly suggest that EhPRL may play an important role in the biology and adaptive response of the parasite to the host environment during amoebic liver abscess development, thereby participating in the pathogenic mechanism.

  18. Kinetic modeling can describe in vivo glycolysis in Entamoeba histolytica.

    Science.gov (United States)

    Saavedra, Emma; Marín-Hernández, Alvaro; Encalada, Rusely; Olivos, Alfonso; Mendoza-Hernández, Guillermo; Moreno-Sánchez, Rafael

    2007-09-01

    Glycolysis in the human parasite Entamoeba histolytica is characterized by the absence of cooperative modulation and the prevalence of pyrophosphate-dependent (over ATP-dependent) enzymes. To determine the flux-control distribution of glycolysis and understand its underlying control mechanisms, a kinetic model of the pathway was constructed by using the software gepasi. The model was based on the kinetic parameters determined in the purified recombinant enzymes, and the enzyme activities, and steady-state fluxes and metabolite concentrations determined in amoebal trophozoites. The model predicted, with a high degree of accuracy, the flux and metabolite concentrations found in trophozoites, but only when the pyrophosphate concentration was held constant; at variable pyrophosphate, the model was not able to completely account for the ATP production/consumption balance, indicating the importance of the pyrophosphate homeostasis for amoebal glycolysis. Control analysis by the model revealed that hexokinase exerted the highest flux control (73%), as a result of its low cellular activity and strong AMP inhibition. 3-Phosphoglycerate mutase also exhibited significant flux control (65%) whereas the other pathway enzymes showed little or no control. The control of the ATP concentration was also mainly exerted by ATP consuming processes and 3-phosphoglycerate mutase and hexokinase (in the producing block). The model also indicated that, in order to diminish the amoebal glycolytic flux by 50%, it was required to decrease hexokinase or 3-phosphoglycerate mutase by 24% and 55%, respectively, or by 18% for both enzymes. By contrast, to attain the same reduction in flux by inhibiting the pyrophosphate-dependent enzymes pyrophosphate-phosphofructokinase and pyruvate phosphate dikinase, they should be decreased > 70%. On the basis of metabolic control analysis, steps whose inhibition would have stronger negative effects on the energy metabolism of this parasite were identified

  19. Genetic Analysis and Combining Ability Studies for Yield Related Characters in Rapeseed

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    Aamar Shehzad

    2015-09-01

    Full Text Available Combining ability analysis has a key position in rapeseed breeding. To estimate the combining ability effects for yield controlling traits in rapeseed, three testers and five lines were crossed using line × tester design in randomized complete block design with three replications. Mean sum of squares of analysis of variances for genotypes were significant for all of the traits; indicating the presence of significant genetic variation. All the interactions between lines and testers exhibited significant results of mean sum of squares for combining ability. Line ‘Duncled’ was found good general combiner for decreased Plant height (PH:-2.0, Days taken to 50% flowering (DF: -15.8 and Days taken to maturity (DM:-3.4 while tester ‘Punjab Sarson” for increased Number of seed/siliqua (SS: 2.2, Number of siliquae/plant (SP: 2.2 and decreased DF (-3.0 traits. Significant general and specific combining ability effects were observed. The best hybrid combination on the basis of specific combining ability effects was “Durre-NIFA × ZN-M-6” for Seed yield/plant (SY: 2.7, DF (-6.1 and DM (-3.5. PH (-0.2, Siliqua length (SL: -0.1, SS (-0.03 and SY (0.2 showed non-additive genetic effects. The half of the characters revealed additive and remaining half showed non-additive genetic effects. The present study unveiled the importance of both type of genetic effects demanding the application of integrated breeding approaches for exploiting the variability. ‘Punjab Sarson × ZN-M-6’ exposed maximum SS (30 and SP (837. Maximum SY (75.9g and minimum DF (64 were showed by ‘Legend × Duncled’. The present research delivers valuable information of genotypes for promoting yield by means of improving yield related characters.

  20. Differences in the Genetic Susceptibility to Age-Related Macular Degeneration Clinical Subtypes

    Science.gov (United States)

    Shen, Ling; Hoffmann, Thomas J.; Melles, Ronald B.; Sakoda, Lori C.; Kvale, Mark N.; Banda, Yambazi; Schaefer, Catherine; Risch, Neil; Jorgenson, Eric

    2015-01-01

    Purpose We compared across age-related macular degeneration (AMD) subtypes the effect of AMD risk variants, their predictive power, and heritability. Methods The prevalence of AMD was estimated among active non-Hispanic white Kaiser Permanente Northern California members who were at least 65 years of age as of June 2013. The genetic analysis included 5,170 overall AMD cases ascertained from electronic health records (EHR), including 1,239 choroidal neovascularization (CNV) cases and 1,060 nonexudative AMD cases without CNV, and 23,130 controls of non-Hispanic white ancestry from the Kaiser Permanente Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort. Imputation was based on the 1000 Genomes Project reference panel. Results The narrow-sense heritability due to common autosomal single nucleotide polymorphisms (SNPs) was 0.37 for overall AMD, 0.19 for AMD unspecified, 0.20 for nonexudative AMD, and 0.60 for CNV. For the 19 previously reported AMD risk loci, the area under the receiver operating characteristic (ROC) curve was 0.675 for overall AMD, 0.640 for AMD unspecified, 0.678 for nonexudative AMD, and 0.766 for CNV. The individual effects on the risk of AMD for 18 of the 19 SNPs were in a consistent direction with those previously reported, including a protective effect of the APOE ε4 allele. Conversely, the risk of AMD was significantly increased in carriers of the ε2 allele. Conclusions These findings provide an independent confirmation of many of the previously identified AMD risk loci, and support a potentially greater role of genetic factors in the development of CNV. The replication of established associations validates the use of EHR in genetic studies of ophthalmologic traits. PMID:26176866

  1. Genetic determinants of serum vitamin B12 and their relation to body mass index.

    Science.gov (United States)

    Allin, Kristine H; Friedrich, Nele; Pietzner, Maik; Grarup, Niels; Thuesen, Betina H; Linneberg, Allan; Pisinger, Charlotta; Hansen, Torben; Pedersen, Oluf; Sandholt, Camilla H

    2016-12-19

    Lower serum vitamin B12 levels have been related to adverse metabolic health profiles, including adiposity. We used a Mendelian randomization design to test whether this relation might be causal. We included two Danish population-based studies (ntotal = 9311). Linear regression was used to test for associations between (1) serum vitamin B12 levels and body mass index (BMI), (2) genetic variants and serum vitamin B12 levels, and (3) genetic variants and BMI. The effect of a genetically determined decrease in serum vitamin B12 on BMI was estimated by instrumental variable regression. Decreased serum vitamin B12 associated with increased BMI (P B12 associated variants associated strongly with serum vitamin B12 (P B12 was associated with a 0.09 kg/m(2) (95% CI 0.05; 0.13) increase in BMI (P = 3 × 10(-5)), whereas a genetically induced 20% decrease in serum vitamin B12 had no effect on BMI [-0.03 (95% CI -0.22; 0.16) kg/m(2)] (P = 0.74). Nevertheless, the strongest serum vitamin B12 variant, FUT2 rs602662, which was excluded from the B12 genetic risk score due to potential pleiotropic effects, showed a per allele effect of 0.15 kg/m(2) (95% CI 0.01; 0.32) on BMI (P = 0.03). This association was accentuated including two German cohorts (ntotal = 5050), with a combined effect of 0.19 kg/m(2) (95% CI 0.08; 0.30) (P = 4 × 10(-4)). We found no support for a causal role of decreased serum vitamin B12 levels in obesity. However, our study suggests that FUT2, through its regulation of the cross-talk between gut microbes and the human host, might explain a part of the observational association between serum vitamin B12 and BMI.

  2. Bridging Molecular Genetics and Biomarkers in Lewy Body and Related Disorders

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    Gilbert J. Ho

    2011-01-01

    Full Text Available Recent advances have been made in defining the genetic and molecular basis of dementia with Lewy bodies (DLBs and related neurodegenerative disorders such as Parkinson's disease (PD and Parkinson's disease dementia (PDD which comprise the spectrum of “Lewy body disorders” (LBDs. The genetic alterations and underlying disease mechanisms in the LBD overlap substantially, suggesting common disease mechanisms. As with the other neurodegenerative dementias, early diagnosis in LBD or even identification prior to symptom onset is key to developing effective therapeutic strategies, but this is dependent upon the development of robust, specific, and sensitive biomarkers as diagnostic tools and therapeutic endpoints. Recently identified mutations in the synucleins and other relevant genes in PD and DLB as well as related biomolecular pathways suggest candidate markers from biological fluids and imaging modalities that reflect the underlying disease mechanisms. In this context, several promising biomarkers for the LBD have already been identified and examined, while other intriguing possible candidates have recently emerged. Challenges remain in defining their correlation with pathological processes and their ability to detect DLB and related disorders, and perhaps a combined array of biomarkers may be needed to distinguish various LBDs.

  3. Association of apelin genetic variants with type 2 diabetes and related clinical features in Chinese Hans

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rong; HU Cheng; WANG Cong-rong; MA Xiao-jing; BAO Yu-qian; XU Jing; LU Jing-yi; QIN Wen; XIANG Kun-san; JIA Wei-ping

    2009-01-01

    Background Apelin is an adipokine that contributes to the pathogenesis of type 2 diabetes. The plasma levels of apelin increased in obese patients and diabetic subjects. This study aimed to investigate the effects of apelin genetic variants on type 2 diabetes and related quantitative traits.Methods We selected three single nucleotide polymorphisms (SNPs) that could capture all common variants in APLN gene region and genotyped them in 1892 type 2 diabetic patients and 1808 normal glucose regulation controls. The clinical features related to glucose metabolism were measured in the controls. The comparison of allele and genotype distribution in the cases and controls were performed by using X2 tests. The association between SNPs and quantitative traits were analyzed using Wilcoxon's rank-sum test.Results None of the SNPs or haplotypes showed evidence of association to type 2 diabetes. However, rs2235306 was nominally associated with fasting plasma glucose levels in the male subjects with normal glucose regulation ((4.93±0.03)vs (5.01±0.03) mmol/L, P=0.04). No significant difference was observed between all three SNPs and other variables. Conclusions APLN SNP rs2235306 was associated with fasting plasma glucose levels in males. It suggests that APLN genetic variants may contribute to clinical features related to glucose metabolism in Chinese population.

  4. Role of genetic mutations in folate-related enzyme genes on Male Infertility

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    Liu, Kang; Zhao, Ruizhe; Shen, Min; Ye, Jiaxin; Li, Xiao; Huang, Yuan; Hua, Lixin; Wang, Zengjun; Li, Jie

    2015-01-01

    Several studies showed that the genetic mutations in the folate-related enzyme genes might be associated with male infertility; however, the results were still inconsistent. We performed a meta-analysis with trial sequential analysis to investigate the associations between the MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G mutations and the MTHFR haplotype with the risk of male infertility. Overall, a total of 37 studies were selected. Our meta-analysis showed that the MTHFR C677T mutation was a risk factor for male infertility in both azoospermia and oligoasthenoteratozoospermia patients, especially in Asian population. Men carrying the MTHFR TC haplotype were most liable to suffer infertility while those with CC haplotype had lowest risk. On the other hand, the MTHFR A1298C mutation was not related to male infertility. MTR A2756G and MTRR A66G were potential candidates in the pathogenesis of male infertility, but more case-control studies were required to avoid false-positive outcomes. All of these results were confirmed by the trial sequential analysis. Finally, our meta-analysis with trial sequential analysis proved that the genetic mutations in the folate-related enzyme genes played a significant role in male infertility. PMID:26549413

  5. Genetics of immunological and inflammatory components in age-related macular degeneration.

    Science.gov (United States)

    Tuo, Jingsheng; Grob, Seanna; Zhang, Kang; Chan, Chi-Chao

    2012-02-01

    Age-related macular degeneration (AMD), affecting 30 to 50 million elder individuals worldwide, is a disease affecting the macular retina and choroid that can lead to irreversible central vision loss and blindness. Recent findings support a role for immunologic processes in AMD pathogenesis, including generation of inflammatory related molecules in the Bruch's membrane, recruitment of macrophages, complement activation, microglial activation and accumulation in the macular lesions. Pro-inflammatory effects of chronic inflammation and oxidative stress can result in abnormal retinal pigment epithelium, photoreceptor atrophy and choroidal neovascularization. The associations of immunological and inflammatory genes, in particular the genes related to innate immunity with AMD support the involvement of various immunological pathways in the AMD pathogenesis. We review the literature on the involvements of inflammatory genes in AMD, highlight recent genetic discoveries, and discuss the potential application of such knowledge in the management of patients with AMD.

  6. Detection and genetic characterization of a novel parvovirus distantly related to human bufavirus in domestic pigs.

    Science.gov (United States)

    Hargitai, Renáta; Pankovics, Péter; Kertész, Attila Mihály; Bíró, Hunor; Boros, Ákos; Phan, Tung Gia; Delwart, Eric; Reuter, Gábor

    2016-04-01

    In this study, a novel parvovirus (strain swine/Zsana3/2013/HUN, KT965075) was detected in domestic pigs and genetically characterized by viral metagenomics and PCR methods. The novel parvovirus was distantly related to the human bufaviruses and was detected in 19 (90.5 %) of the 21 and five (33.3 %) of the 15 faecal samples collected from animals with and without cases of posterior paraplegia of unknown etiology from five affected farms and one control farm in Hungary, respectively. Swine/Zsana3/2013/HUN is highly prevalent in domestic pigs and potentially represents a novel parvovirus species in the subfamily Parvovirinae.

  7. Optimal approximation of head-related transfer function's pole-zero model based on genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; MA Hao; WU Zhen-yang

    2006-01-01

    In the research on spatial hearing and virtual auditory space,it is important to effectively model the head-related transfer functions (HRTFs).Based on the analysis of the HRTFs' spectrum and some perspectives of psychoacoustics,this paper applied multiple demes' parallel and real-valued coding genetic algorithm (GA) to approximate the HRTFs' zero-pole model.Using the logarithmic magnitude's error criterion for the human auditory sense,the results show that the performance of the GA is on the average 39% better than that of the traditional Prony method,and 46% better than that of the Yule-Walker algorithm.

  8. Mental quality of life is related to a cytokine genetic pathway.

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    Dounya Schoormans

    Full Text Available BACKGROUND: Quality of life (QoL in patients with chronic disease is impaired and cannot be solely explained by disease severity. We explored whether genetic variability and activity contributes to QoL in patients with Marfan syndrome (MFS, a genetic connective tissue disorder. METHODOLOGY/PRINCIPAL FINDINGS: In 121 MFS patients, patient characteristics (i.e. demographics and MFS-related symptoms were assessed. Patients completed the SF-36 to measure QoL. In addition, transcriptome wide gene expression and 484 Single Nucleotide Polymorphysms (SNPs in cytokine genes were available. QoL was first analyzed and associated with patient characteristics. Patients' physical QoL was impaired and weakly related with age and scoliosis, whereas mental quality of life (MCS was normal. To explain a largely lacking correlation between disease severity and QoL, we related genome wide gene expression to QoL. Patients with lower MCS scores had high expression levels of CXCL9 and CXCL11 cytokine-related genes (p=0.001; p=0.002; similarly, patients with low vitality scores had high expression levels of CXCL9, CXCL11 and IFNA6 cytokine-related genes (p=0.02; p=0.02; p=0.04, independent of patient characteristics. Subsequently, we associated cytokine related SNPs to mental QoL (MCS and vitality. SNP-cluster in the IL4R gene showed a weak association with MCS and vitality (strongest association p=0.0017. Although overall mental QoL was normal, >10% of patients had low scores for MCS and vitality. Post-hoc analysis of systemic inflammatory mediators showed that patients with lowest MCS and vitality scores had high levels of CCL11 cytokine (p=0.03; p=0.04. CONCLUSIONS/SIGNIFICANCE: Variation in the cytokine genetic pathway and its activation is related to mental QoL. These findings might allow us to identify and, ultimately, treat patients susceptible to poor QoL.

  9. Differentiation of Entamoeba histolytica/Entamoeba dispar by the polymerase chain reaction in stool samples of patients with gastrointestinal symptoms in the Sanliurfa Province.

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    Zeyrek, Fadile Yıldız; Turgay, Nevin; Unver, Aysegül; Ustün, Sebnem; Akarca, Ulus; Töz, Seray

    2013-01-01

    We aimed to diagnose amebiasis and also identify Entamoeba histolytica (E. histolytica) and Entamoeba dispar (E. dispar) in patients with gastrointestinal symptoms in an endemic region in Turkey. Stool samples obtained from 181 patients with gastrointestinal symptoms from the Harran University Hospital of Sanliurfa were examined for the diagnosis of amebiasis by the three methods which are as follows:- In house polymerase chain reaction (PCR) targeting the 135 base pair region located on the small-subunit ribosomal RNA (SSU rRNA) gene to differentiate E. histolytica from E. dispar; and the commercial kit, RIDASCREEN® stool ELISA, that identifies Entamoeba sensu lato antigen and microscopical examination of Trichrome stained smears of stool samples. Positivity for E. histolytica/E. dispar complex was found to be 79 (43.6%) by microscopy versus 83 (45.9%) by PCR out of 181 stool samples. A total of 45 patients were found to be positive by the antigen detection method. PCR and microscopy were both positive in 59 samples. The number of patients infected with E. dispar (39.8%) was found to be higher than E. histolytica (3.3%) while 5 patients (2.8%) had mixed E. histolytica+E. dispar infections according to PCR results. Routine diagnosis of amebiasis by a combination of microscopy and antigen detection technique should be complemented with a PCR assay as a reference test for sensitive differentiation of both species.

  10. Validation and utilization of PCR for differential diagnosis and prevalence determination of Entamoeba histolytica/Entamoeba dispar in Salvador City, Brazil.

    Science.gov (United States)

    Santos, Fred Luciano Neves; Gonçalves, Marilda de Souza; Soares, Neci Matos

    2011-01-01

    Amoebiasis is an infection caused by Entamoeba histolytica and is a potential health risk in countries in which health barriers are inappropriate. Since the discovery of Entamoeba dispar, the prevalence of amoebiasis has been modified. This study has standardized the PCR technique applied for the diagnosis of different species of the E. histolytica/E. dispar complex and has evaluated the prevalence of infection among patients attending private and public clinical laboratories in Salvador City, Bahia State, Brazil. Analysis of 52,704 stool samples by microscopic examination demonstrated that 1,788 (3.4%) were positive for the E. histolytica/E. dispar complex and infection occurred more often in samples originated from public clinical laboratories (5.0%) than those that came from private laboratories (3.2%). PCR performed in approximately 15% (262) E. histolytica/E. dispar complex positive samples, randomly chosen, amplified 227 samples (86.6%), all of them positive for E. dispar. The non-amplified 35 samples (13.4%) were also negative for E. histolytica-specific galactose adhesin. Moreover, to exclude a probable infection caused by E. hartmanni, morphometric analysis demonstrated that non-amplified samples had cyst sizes comparable to E. histolytica/E. dispar (>10 µm). The absence of amplification of these samples indicates the presence of PCR inhibitors in the stool samples or the presence of DNA from Entamoeba species other than E. dispar, E. histolytica or E. hartmanni.

  11. Attitudes toward genetic testing among the general population and relatives of patients with a severe genetic disease

    DEFF Research Database (Denmark)

    Hietala, M; Hakonen, A; Aro, A R

    1995-01-01

    In the present study we explore the attitudes of the Finnish population toward genetic testing by conducting a questionnaire study of a stratified sample of the population as well as of family members of patients with a severe hereditary disease, aspartylglucosaminuria (AGU). The questionnaire...... members of AGU patients have a favorable attitude toward genetic testing. However, a commonly expressed reason against testing was that test results might lead to discrimination in employment or insurance policies. Based on the responses, we predict that future genetic testing programs will most probably...... evaluated attitudes toward gene tests in general and also respondents' preparedness to undergo gene tests for predictive testing, carrier detection, prenatal diagnosis, and selective abortion, in theoretical situations. The results of the study indicate that both the Finnish population in general and family...

  12. Technical advances in trigger-induced RNA interference gene silencing in the parasite Entamoeba histolytica.

    Science.gov (United States)

    Khalil, Mohamed I; Foda, Bardees M; Suresh, Susmitha; Singh, Upinder

    2016-03-01

    Entamoeba histolytica has a robust endogenous RNA interference (RNAi) pathway. There are abundant 27 nucleotide (nt) anti-sense small RNAs (AS sRNAs) that target genes for silencing and the genome encodes many genes involved in the RNAi pathway such as Argonaute proteins. Importantly, an E. histolytica gene with numerous AS sRNAs can function as a "trigger" to induce silencing of a gene that is fused to the trigger. Thus, the amebic RNAi pathway regulates gene expression relevant to amebic biology and has additionally been harnessed as a tool for genetic manipulation. In this study we have further improved the trigger-induced gene silencing method. We demonstrate that rather than using the full-length gene, a short portion of the coding region fused to a trigger is sufficient to induce silencing; the first 537 bp of the E. histolytica rhomboid gene (EhROM1) fused in-frame to the trigger was sufficient to silence EhROM1. We also demonstrated that the trigger method could silence two amebic genes concomitantly; fusion of the coding regions of EhROM1 and transcription factor, EhMyb, in-frame to a trigger gene resulted in both genes being silenced. Alternatively, two genes can be silenced sequentially: EhROM1-silenced parasites with no drug selection plasmid were transfected with trigger-EhMyb, resulting in parasites with both EhROM1 and EhMyb silenced. With all approaches tested, the trigger-mediated silencing was substantive and silencing was maintained despite loss of the G418 selectable marker. All gene silencing was associated with generation of AS sRNAs to the silenced gene. We tested the reversibility of the trigger system using inhibitors of histone modifications but found that the silencing was highly stable. This work represents a technical advance in the trigger gene silencing method in E. histolytica. Approaches that readily silence multiple genes add significantly to the genetic toolkit available to the ameba research community. Copyright © 2016

  13. Differential expression and immunolocalization of antioxidant enzymes in Entamoeba histolytica isolates during metronidazole stress.

    Science.gov (United States)

    Iyer, Lakshmi Rani; Singh, Nishant; Verma, Anil Kumar; Paul, Jaishree

    2014-01-01

    Entamoeba histolytica infections are endemic in the Indian subcontinent. Five to eight percent of urban population residing under poor sanitary conditions suffers from Entamoeba infections. Metronidazole is the most widely prescribed drug used for amoebiasis. In order to understand the impact of metronidazole stress on the parasite, we evaluated the expression of two antioxidant enzymes, peroxiredoxin and FeSOD, in Entamoeba histolytica isolates during metronidazole stress. The results reveal that, under metronidazole stress, the mRNA expression levels of these enzymes did not undergo any significant change. Interestingly, immunolocalization studies with antibodies targeting peroxiredoxin indicate differential localization of the protein in the cell during metronidazole stress. In normal conditions, all the Entamoeba isolates exhibit presence of peroxiredoxin in the nucleus as well as in the membrane; however with metronidazole stress the protein localized mostly to the membrane. The change in the localization pattern was more pronounced when the cells were subjected to short term metronidazole stress compared to cells adapted to metronidazole. The protein localization to the cell membrane could be the stress response mechanism in these isolates. Colocalization pattern of peroxiredoxin with CaBp1, a cytosolic protein, revealed that the membrane and nuclear localization was specific to peroxiredoxin during metronidazole stress.

  14. Solution structure of the pore-forming protein of Entamoeba histolytica

    NARCIS (Netherlands)

    Hecht, O.; van Nuland, N.A.J.; Schleinkofer, K.; Dingley, A.J.; Bruhn, H.; Leippe, M.; Grötzinger, J.

    2004-01-01

    Amoebapore A is a 77-residue protein from the protozoan parasite and human pathogen Entamoeba histolytica. Amoebapores lyse both bacteria and eukaryotic cells by pore formation and play a pivotal role in the destruction of host tissues during amoebiasis, one of the most life-threatening parasitic di

  15. Entamoeba histolytica and E. dispar infections in captive macaques (Macaca fascicularis) in the Philippines.

    Science.gov (United States)

    Rivera, Windell L; Yason, John Anthony D L; Adao, Davin Edric V

    2010-01-01

    Entamoeba histolytica is a protozoan parasite that infects man and animals. This parasite has a global distribution and the disease it causes is usually characterized by diarrhea. In order to detect the parasite, it is necessary to differentiate it from Entamoeba dispar. E. dispar appears morphologically similar to E. histolytica but does not cause disease and tissue invasion. This study reports on the prevalence of E. histolytica and E. dispar among captive macaques in a primate facility in the Philippines. PCR was used to correctly identify both Entamoeba species. Indirect fluorescent antibody test (IFAT) was also performed to determine the seroprevalence of amebiasis in the captive macaques. Based on PCR targeting of the peroxiredoxin gene, of the 96 stool samples collected, 23 (24%) contained E. histolytica while 32 (33%) contained E. dispar. IFAT revealed 26 (27%) serum samples positive for antibodies against E. histolytica. Sequence analysis of the 18S rRNA gene showed that the 23 E. histolytica isolates were identical to human E. histolytica isolates deposited in the GenBank and not Entamoeba nuttalli as found in macaques in other recent reports. The Philippines is a major exporter of monkeys for biomedical research purposes, so screening animals before transporting them to other locations lessens the risk of spreading zoonoses to a wider area. This is the first report of the molecular detection of E. histolytica and E. dispar among macaques in the Philippines. This study complements the limited information available on the animal hosts of E. histolytica in the Philippines.

  16. Literature Reference for Entamoeba histolytica (Journal of Clinical Microbiology. 2005. 43(11): 5491–5497)

    Science.gov (United States)

    Procedures are described for analysis of clinical samples and may be adapted for assessment of solid, particulate, liquid and water samples. The method is a real-time PCR assay that targets the 18S rRNA gene sequence of Entamoeba histolytica.

  17. Risk of underdiagnosing amebic dysentery due to false-negative Entamoeba histolytica antigen detection.

    Science.gov (United States)

    Prim, Núria; Escamilla, Pilar; Solé, Roser; Llovet, Teresa; Soriano, Germán; Muñoz, Carmen

    2012-08-01

    Entamoeba histolytica antigen assays on stool are widely used to diagnose amebiasis. We report a case of confirmed amebic colitis with a false-negative antigen detection that became positive after treatment. Our results indicate that these assays may underdiagnose acute amebic infection when used alone and should be used cautiously. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Entamoeba moshkovskii Is Associated With Diarrhea in Infants and Causes Diarrhea and Colitis in Mice

    Science.gov (United States)

    Shimokawa, Chikako; Kabir, Mamun; Taniuchi, Mami; Mondal, Dinesh; Kobayashi, Seiki; Ali, Ibne Karim M.; Sobuz, Shihab U.; Senba, Masachika; Houpt, Eric; Haque, Rashidul; Petri, William A.; Hamano, Shinjiro

    2012-01-01

    Background.Entamoeba moshkovskii is prevalent in developing countries and morphologically indistinguishable from pathogenic Entamoeba histolytica and nonpathogenic Entamoeba dispar. It is not known if E. moshkovskii is pathogenic. Methods.Mice were intracecally challenged with the trophozoites of each Entamoeba spp. to test the ability to cause diarrhea, and infants in Bangladesh were prospectively observed to see if newly acquired E. moshkovskii infection was associated with diarrhea. Results.E. moshkovskii and E. histolytica caused diarrhea and weight loss in susceptible mice. E. dispar infected none of the mouse strains tested. In Mirpur, Dhaka, Bangladesh, E. moshkovskii, E. histolytica, and E. dispar were identified in 42 (2.95%), 66 (4.63%), and 5 (0.35%), respectively, of 1426 diarrheal episodes in 385 children followed prospectively from birth to one year of age. Diarrhea occurred temporally with acquisition of a new E. moshkovskii infection: in the 2 months preceding E. moshkvskii-associated diarrhea, 86% (36 of 42) of monthly surveillance stool samples were negative for E. moshkovskii. Conclusions.E. moshkovskii was found to be pathogenic in mice. In children, the acquisition of E. moshkovskii infection was associated with diarrhea. These data are consistent with E. moshkovskii causing disease, indicating that it is important to reexamine its pathogenicity. PMID:22723640

  19. High-resolution electron microscopical study of cyst walls of Entamoeba spp.

    Science.gov (United States)

    Chávez-Munguía, Bibiana; Martínez-Palomo, Adolfo

    2011-01-01

    Knowledge of the fine structural organization, molecular composition and permeability properties of the cell surface of intestinal protozoan cysts is important to understand the biologic basis of their resistance. Recent studies on the biology of the cyst walls of Entamoeba histolytica and Entamoeba invadens have considerably advanced knowledge on the cellular processes involved in the transport and surface deposition of the main cyst wall components. Using transmission electron microscopy, cytochemistry, scanning electron microscopy and freeze-fracture techniques, we have obtained new information. In mature cysts the permeability of Entamoeba cysts is limited to small molecules not by the cyst wall, but by the plasma membrane, as demonstrated with the use of ruthenium red as an electron-dense tracer. Cell walls of E. histolytica cysts are made up of five to seven layers of unordered fibrils 7-8 nm thick. Alcian blue stains a regular mesh of fibrils approximately 4 nm thick, running perpendicularly to the cyst wall. In addition, abundant ionogenic groups are seen in cyst walls treated with cationized ferritin. In the mature cysts of E. histolytica and E. invadens small cytoplasmic vesicles with granular material were in close contact with the plasma membrane, suggesting a process of fusion and deposition of granular material to the cell wall. The plasma membrane of mature cysts is devoid of intramembrane particles when analyzed with the freeze-fracture technique. When viewed with scanning electron microscopy the surface of E. histolytica cysts clearly differs from that of Entamoeba coli and E. invadens.

  20. Oxidative Stress-Related Genetic Variants May Modify Associations of Phthalate Exposures with Asthma

    Science.gov (United States)

    Wang, I-Jen; Karmaus, Wilfried J. J.

    2017-01-01

    Background: Phthalate exposure may increase the risk of asthma. Little is known about whether oxidative-stress related genes may alter this association. First, this motivated us to investigate whether genetic polymorphisms of the oxidative-stress related genes glutathione S-transferase Mu 1 (GSTM1), glutathione S-transferase pi 1 (GSTP1), superoxide dismutase 2 (SOD2), catalase (CAT), myeloperoxidase (MPO), and EPHX1 in children are associated with phthalate urine concentrations. Second, we addressed the question whether these genes may affect the influence of phthalates on asthma. Methods: In a case-control study composed of 126 asthmatic children and 327 controls, urine phthalate metabolites (monoethyl phthalate (MEP), monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), and mono(2-ethyl-5-hydroxyhexyl)phthalate (MEHHP) were measured by UPLC-MS/MS at age 3. Genetic variants were analyzed by TaqMan assay. Information on asthma and environmental exposures was also collected. Analyses of variance and logistic regressions were performed. Results: Urine MEHHP levels were associated with asthma (adjusted OR 1.33, 95% CI (1.11–1.60). Children with the GSTP1 (rs1695) AA and SOD2 (rs5746136) TT genotypes had higher MEHHP levels as compared to GG and CC types, respectively. Since only SOD2 TT genotype was significantly associated with asthma (adjusted OR (95% CI): 2.78 (1.54–5.02)), we estimated whether SOD2 variants modify the association of MEHHP levels and asthma. As MEHHP concentrations were dependent on GSTP1 and SOD2, but the assessment of interaction requires independent variables, we estimated MEHHP residuals and assessed their interaction, showing that the OR for SOD2 TT was further elevated to 3.32 (1.75–6.32) when the residuals of MEHHP were high. Conclusions: Urine phthalate metabolite concentrations are associated with oxidative-stress related genetic variants. Genetic variants of SOD2, considered to be reflect oxidative stress metabolisms, might

  1. Summarizing Relational Data Using Semi-Supervised Genetic Algorithm-Based Clustering Techniques

    Directory of Open Access Journals (Sweden)

    Rayner Alfred

    2010-01-01

    Full Text Available Problem statement: In solving a classification problem in relational data mining, traditional methods, for example, the C4.5 and its variants, usually require data transformations from datasets stored in multiple tables into a single table. Unfortunately, we may loss some information when we join tables with a high degree of one-to-many association. Therefore, data transformation becomes a tedious trial-and-error work and the classification result is often not very promising especially when the number of tables and the degree of one-to-many association are large. Approach: We proposed a genetic semi-supervised clustering technique as a means of aggregating data stored in multiple tables to facilitate the task of solving a classification problem in relational database. This algorithm is suitable for classification of datasets with a high degree of one-to-many associations. It can be used in two ways. One is user-controlled clustering, where the user may control the result of clustering by varying the compactness of the spherical cluster. The other is automatic clustering, where a non-overlap clustering strategy is applied. In this study, we use the latter method to dynamically cluster multiple instances, as a means of aggregating them and illustrate the effectiveness of this method using the semi-supervised genetic algorithm-based clustering technique. Results: It was shown in the experimental results that using the reciprocal of Davies-Bouldin Index for cluster dispersion and the reciprocal of Gini Index for cluster purity, as the fitness function in the Genetic Algorithm (GA, finds solutions with much greater accuracy. The results obtained in this study showed that automatic clustering (seeding, by optimizing the cluster dispersion or cluster purity alone using GA, provides one with good results compared to the traditional k-means clustering. However, the best result can be achieved by optimizing the combination values of both the cluster

  2. Different genetic pathways in leukemogenesis for patients presenting with therapy-related myelodysplasia and therapy-related acute myeloid leukemia.

    Science.gov (United States)

    Pedersen-Bjergaard, J; Pedersen, M; Roulston, D; Philip, P

    1995-11-01

    Development of myelodysplasia (MDS) with subsequent progression to acute myeloid leukemia (AML) is an example of the multistep process of malignant transformation in which each step often relates to genetic abnormalities that can be directly seen as chromosomal aberrations. Therapy-related MDS and AML (t-MDS and t-AML) may serve as an ideal model for a study of the genetic evolution of MDS and AML because chromosomal abnormalities are observed in most cases and because the disease is often diagnosed early due to a close patient follow-up. The cytogenetic characteristics at diagnosis were studied in 137 consecutive cases of t-MDS and t-AML, including 22 new cases, and correlated with the clinical characteristics and the course of the disease. Balanced translocations to chromosome bands 11q23 and 21q22 represent primary steps in pathways leading directly to overt t-AML. Specific chromosomal deletions or losses, on the other hand, represent primary or secondary events in alternative pathways leading to t-MDS with potential for subsequent transformation to overt t-AML. Loss of a whole chromosome 7 (-7) or deletion of its long arm (7q-) and deletion of the long arm of a chromosome 5 (5q-) were the most frequent primary abnormalities significantly related to t-MDS. Loss of a whole chromosome 5 (-5) was also a primary event, but surprisingly, was observed equally in t-MDS and in t-AML. Deletion of chromosome 13, including bands q13q14, was another less common primary aberration of t-MDS. Except for -7 and del(13q), these primary aberrations were most often observed together with secondary abnormalities. These included balanced aberrations involving band 3q26 and various deletions of chromosome 3, a gain of a whole chromosome 8, deletions of the short arm or loss of chromosomes 12 and 17, loss of a whole chromosome 18, and deletions of the short arm of chromosome 21. Deletions or loss or chromosomes 5 and 7 were significantly associated with previous therapy with

  3. Sensibilidad de trofozoítos de Entamoeba histolytica a ivermectina Sensibility of Entamoeba histolytica trophozoites to ivermectin

    Directory of Open Access Journals (Sweden)

    Francisco González-Salazar

    2009-06-01

    Full Text Available La amibiasis producida por Entamoeba histolytica es un problema de salud pública. Las formas clínicas más frecuentes son la disentería y el absceso hepático amibiano. En el mundo se notifican anualmente 50 millones de casos y más de 100 000 muertes por esta enfermedad. El ciclo de vida de E. histolytica tiene dos fases: trofozoíto y quiste. Los trofozoítos son los responsables de producir enfermedad. El tratamiento actual para la amibiasis incluye medicamentos con efectos colaterales serios. La ivermectina es un macrólido con actividad contra endoparásitos y ectoparásitos causantes de strongiloidosis, filariasis, oncocercosis, sarna y pediculosis. Su uso está extendido a casi todo el mundo y se lo reconoce como un medicamento seguro. El objetivo de este trabajo fue determinar la sensiblidad in vitro de trofozoítos de E. histolytica al tratamiento con ivermectina. Para determinar su sensibilidad a la droga, se utilizaron trofozoítos de E. histolytica cultivados en medio PEHPS. Durante su fase de crecimiento logarítmico se expusieron a diferentes concentraciones de ivermectina. Como controles se usaron otras drogas antiparasitarias. Se prepararon diluciones seriadas de cada droga, luego se agregaron a tubos con parásitos (2 x 10(4 células/ml. Se incubó por 72 h y luego se determinó el porcentaje de inhibición de crecimiento calculado por análisis Probit. La ivermectina tiene actividad contra trofozoítos de E. histolytica. La dosis de ivermectina que produjo el 50% de inhibición de crecimiento fue de 6.40 mg/ml. Esta dosis fue mayor a la encontrada con otras drogas antiparasitarias. Falta demostrar su actividad in vivo en modelos animales.Amebiasis caused by Entamoeba histolytica is a problem of public world health. The most frequent clinical presentation are the dysentery and the amebic liver abscess. Fifty millions of cases and more than 100.000 deaths for this disease are reported annually worldwide. The life cycle of E

  4. Associations between an obesity related genetic variant (FTO rs9939609 and prostate cancer risk.

    Directory of Open Access Journals (Sweden)

    Sarah J Lewis

    Full Text Available Observational studies suggest that obese men have a lower risk of incident prostate cancer, but an increased risk of advanced and fatal cancers. These observations could be due to confounding, detection bias, or a biological effect of obesity. Genetic studies are less susceptible to confounding than observational epidemiology and can suggest how associations between phenotypes (such as obesity and diseases arise. To determine whether the associations between obesity and prostate cancer are causal, we conducted a genetic association study of the relationship between a single nucleotide polymorphism known to be associated with obesity (FTO rs9939609 and prostate cancer. Data are from a population-based sample of 1550 screen-detected prostate cancers, 1815 age- and general practice matched controls with unrestricted prostate specific antigen (PSA values and 1175 low-PSA controls (PSA <0.5 ng/ml. The rs9939609 A allele, which was associated with higher BMI in the sample, was inversely associated with overall (odds ratio (OR versus all controls  = 0.93; 95% confidence interval (CI: 0.85-1.02 p = 0.12 per allele and low-grade (OR = 0.90; 0.81-0.99 p = 0.03 per allele prostate cancer risk, but positively associated with high-grade cancer among cases (OR high- versus low-grade cancer  = 1.16; 0.99-1.37 p = 0.07 per allele. Although evidence for these effects was weak, they are consistent with observational data based on BMI phenotypes and suggest that the observed association between obesity and prostate cancer is not due to confounding. Further research should confirm these findings, extend them to other BMI-related genetic variants and determine whether they are due to detection bias or obesity-related hormonal changes.Controlled-Trials.com ISRCTN20141297.

  5. Health status of cardiac genetic disease patients and their at-risk relatives.

    Science.gov (United States)

    Ingles, Jodie; Yeates, Laura; Hunt, Lauren; McGaughran, Julie; Scuffham, Paul A; Atherton, John; Semsarian, Christopher

    2013-05-25

    Health status is an important outcome measure that incorporates multiple dimensions of health, including symptoms, functional status, and psychosocial factors. While health status has been shown to be a predictor for hospital readmission, morbidity and mortality in the heart failure setting, there are limited data in cardiac genetic disease. We examined health status in a number of cardiac genetic disease groups compared to the general Australian population. A total of 409 individuals were assessed. Individuals with inherited cardiomyopathies [hypertrophic cardiomyopathy (HCM), familial dilated cardiomyopathy (FDC), arrhythmogenic right ventricular cardiomyopathy (ARVC)] and primary arrhythmogenic disorders [long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT)], as well as their first-degree relatives, completed the Medical Outcomes Survey Short Form-36 (SF-36). The physical and mental component scores (PCS and MCS) and SF-6D utility score were assessed. Patients with HCM (p<0.001), FDC (p<0.05), and CPVT (p<0.05) were found to have a significantly lower PCS, while patients with LQTS (p<0.01) had a lower MCS. Individuals at risk of HCM (p<0.0001) and genotype positive-phenotype negative HCM patients (p<0.01) both had a higher PCS and utility scores compared to the clinically affected HCM population. Individuals at risk of LQTS had significantly higher PCS than those with a clinical diagnosis of LQTS (p<0.05) and similarly individuals at risk of FDC had significantly higher PCS than FDC patients (p<0.05). In HCM, female gender (p=0.002), presence of co-morbidities (p<0.0001) and higher NYHA functional class (p<0.0001) were predictors of a lower PCS. Patients with a clinical diagnosis of a genetic heart disease have an impaired health status, related to both physical and mental function. Clinical management strategies in such patient groups need to consider health status as an important outcome measure. Copyright © 2011 Elsevier

  6. Genetic and clinical characteristics of NEFL-related Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Horga, Alejandro; Laurà, Matilde; Jaunmuktane, Zane; Jerath, Nivedita U; Gonzalez, Michael A; Polke, James M; Poh, Roy; Blake, Julian C; Liu, Yo-Tsen; Wiethoff, Sarah; Bettencourt, Conceição; Lunn, Michael Pt; Manji, Hadi; Hanna, Michael G; Houlden, Henry; Brandner, Sebastian; Züchner, Stephan; Shy, Michael; Reilly, Mary M

    2017-07-01

    To analyse and describe the clinical and genetic spectrum of Charcot-Marie-Tooth disease (CMT) caused by mutations in the neurofilament light polypeptide gene (NEFL). Combined analysis of newly identified patients with NEFL-related CMT and all previously reported cases from the literature. Five new unrelated patients with CMT carrying the NEFL mutations P8R and N98S and the novel variant L311P were identified. Combined data from these cases and 62 kindreds from the literature revealed four common mutations (P8R, P22S, N98S and E396K) and three mutational hotspots accounting for 37 (55%) and 50 (75%) kindreds, respectively. Eight patients had de novo mutations. Loss of large-myelinated fibres was a uniform feature in a total of 21 sural nerve biopsies and 'onion bulb' formations and/or thin myelin sheaths were observed in 14 (67%) of them. The neurophysiological phenotype was broad but most patients with E90K and N98S had upper limb motor conduction velocities <38 m/s. Age of onset was ≤3 years in 25 cases. Pyramidal tract signs were described in 13 patients and 7 patients were initially diagnosed with or tested for inherited ataxia. Patients with E90K and N98S frequently presented before age 3 years and developed hearing loss or other neurological features including ataxia and/or cerebellar atrophy on brain MRI. NEFL-related CMT is clinically and genetically heterogeneous. Based on this study, however, we propose mutational hotspots and relevant clinical-genetic associations that may be helpful in the evaluation of NEFL sequence variants and the differential diagnosis with other forms of CMT. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Clinical, genetic, and brain sonographic features related to Parkinson's disease in Gaucher disease.

    Science.gov (United States)

    Böttcher, Tobias; Rolfs, Arndt; Meyer, Bianca; Grossmann, Annette; Berg, Daniela; Kropp, Peter; Benecke, Reiner; Walter, Uwe

    2013-10-01

    Homozygous or compound heterozygous mutations in the glucocerebrosidase gene cause Gaucher disease. Moreover, heterozygous glucocerebrosidase gene mutations represent the most common genetic risk factor for Parkinson's disease (PD) known so far. Substantia nigra (SN) hyperechogenicity, a sonographic feature thought to reflect iron accumulation, has been described in both PD and Gaucher disease patients. Here we studied how clinical, genetic, and brain sonographic findings relate to the occurrence of PD in Gaucher disease. Sixteen Gaucher disease patients, 12 PD patients, and 32 control subjects were enrolled. The glucocerebrosidase genotypes were identified by DNA sequencing. All subjects underwent transcranial ultrasound, and eight Gaucher disease patients additionally MRI for comparison with SN ultrasound findings. SN hyperechogenicity and reduced echogenicity of brainstem raphe were more frequent in Gaucher disease patients (62, 37 %) than in controls (12, 12 %; p Gaucher disease patients was unrelated to type or severity of glucocerebrosidase gene mutation, but correlated with iron-sensitive MRI-T2 hypointensity of SN pars compacta, and with age at start of enzyme replacement therapy. While none of the five Gaucher disease patients with signs of PD (definite PD, n = 4; early PD, n = 1) had severe glucocerebrosidase gene mutations known to cause neuronopathic Gaucher disease, all carried a N370S allele, previously reported to predict non-neuronopathic Gaucher disease. Hyposmia, higher non-motor symptoms score (constipation, depression, executive dysfunction), and SN hyperechogenicity were characteristic features of Gaucher disease-related PD. We conclude that the combined clinical, genetic, and transcranial sonographic assessment may improve the PD risk evaluation in Gaucher disease.

  8. Risk of colorectal adenomas in relation to meat consumption, meat preparation, and genetic susceptibility in a Dutch population

    NARCIS (Netherlands)

    Tiemersma, E.W.; Voskuil, D.W.; Bunschoten, A.; Kok, F.J.; Kampman, E.

    2004-01-01

    Objective: We studied the association between meat consumption and colorectal adenomas, and potential influence of genetic susceptibility to heterocyclic aromatic amines (HCAs) formed during meat cooking at high temperatures. Methods: We studied HCA concentration in relation to preparation habits am

  9. Unified method to integrate and blend several, potentially related, sources of information for genetic evaluation.

    Science.gov (United States)

    Vandenplas, Jérémie; Colinet, Frederic G; Gengler, Nicolas

    2014-09-30

    A condition to predict unbiased estimated breeding values by best linear unbiased prediction is to use simultaneously all available data. However, this condition is not often fully met. For example, in dairy cattle, internal (i.e. local) populations lead to evaluations based only on internal records while widely used foreign sires have been selected using internally unavailable external records. In such cases, internal genetic evaluations may be less accurate and biased. Because external records are unavailable, methods were developed to combine external information that summarizes these records, i.e. external estimated breeding values and associated reliabilities, with internal records to improve accuracy of internal genetic evaluations. Two issues of these methods concern double-counting of contributions due to relationships and due to records. These issues could be worse if external information came from several evaluations, at least partially based on the same records, and combined into a single internal evaluation. Based on a Bayesian approach, the aim of this research was to develop a unified method to integrate and blend simultaneously several sources of information into an internal genetic evaluation by avoiding double-counting of contributions due to relationships and due to records. This research resulted in equations that integrate and blend simultaneously several sources of information and avoid double-counting of contributions due to relationships and due to records. The performance of the developed equations was evaluated using simulated and real datasets. The results showed that the developed equations integrated and blended several sources of information well into a genetic evaluation. The developed equations also avoided double-counting of contributions due to relationships and due to records. Furthermore, because all available external sources of information were correctly propagated, relatives of external animals benefited from the integrated

  10. Genetic and non-iodine-related factors in the aetiology of nodular goitre.

    Science.gov (United States)

    Knudsen, Nils; Brix, Thomas Heiberg

    2014-08-01

    Genetic and a large number of environmental non-iodine-related factors play a role in the cause of nodular goitre. Most evidence for the influence of genetic and environmental factors in the cause of goitre is from cross-sectional, population-based studies. Only a few studies have included prospective data on risk factors for nodular goitre, although few prospective data are available on the effect of iodine and tobacco smoking on goitre development. Goitre is not one single phenotype. Many epidemiological studies do not distinguish diffuse from nodular goitre, as the investigated parameter is often thyroid volume or frequency with increased thyroid volume. Moreover, information on the presence and effect of gene-environment, gene-gene, and environment-environment effect modifications is limited. Thus, firm conclusions about the relative contributions and causality of the investigated risk factors should be made with caution. Smoking seems to be an established risk factor for nodular goitre, possibly with effect modification from iodine intake, as the risk associated with smoking is smaller or absent in areas with sufficient iodine intake. The use of oral contraceptives might have protective effects against goitre, and childbirth is an increased risk factor for goitre in areas with non-optimal iodine intake. Insulin resistance is a recently investigated risk factor, and the risk of goitre may be reversible with metformin treatment. Iodine remains the major environmental risk factor for nodular goitre.

  11. Determining Relative Importance and Effective Settings for Genetic Algorithm Control Parameters.

    Science.gov (United States)

    Mills, K L; Filliben, J J; Haines, A L

    2015-01-01

    Setting the control parameters of a genetic algorithm to obtain good results is a long-standing problem. We define an experiment design and analysis method to determine relative importance and effective settings for control parameters of any evolutionary algorithm, and we apply this method to a classic binary-encoded genetic algorithm (GA). Subsequently, as reported elsewhere, we applied the GA, with the control parameter settings determined here, to steer a population of cloud-computing simulators toward behaviors that reveal degraded performance and system collapse. GA-steered simulators could serve as a design tool, empowering system engineers to identify and mitigate low-probability, costly failure scenarios. In the existing GA literature, we uncovered conflicting opinions and evidence regarding key GA control parameters and effective settings to adopt. Consequently, we designed and executed an experiment to determine relative importance and effective settings for seven GA control parameters, when applied across a set of numerical optimization problems drawn from the literature. This paper describes our experiment design, analysis, and results. We found that crossover most significantly influenced GA success, followed by mutation rate and population size and then by rerandomization point and elite selection. Selection method and the precision used within the chromosome to represent numerical values had least influence. Our findings are robust over 60 numerical optimization problems.

  12. FINDbase: a relational database recording frequencies of genetic defects leading to inherited disorders worldwide.

    Science.gov (United States)

    van Baal, Sjozef; Kaimakis, Polynikis; Phommarinh, Manyphong; Koumbi, Daphne; Cuppens, Harry; Riccardino, Francesca; Macek, Milan; Scriver, Charles R; Patrinos, George P

    2007-01-01

    Frequency of INherited Disorders database (FINDbase) (http://www.findbase.org) is a relational database, derived from the ETHNOS software, recording frequencies of causative mutations leading to inherited disorders worldwide. Database records include the population and ethnic group, the disorder name and the related gene, accompanied by links to any corresponding locus-specific mutation database, to the respective Online Mendelian Inheritance in Man entries and the mutation together with its frequency in that population. The initial information is derived from the published literature, locus-specific databases and genetic disease consortia. FINDbase offers a user-friendly query interface, providing instant access to the list and frequencies of the different mutations. Query outputs can be either in a table or graphical format, accompanied by reference(s) on the data source. Registered users from three different groups, namely administrator, national coordinator and curator, are responsible for database curation and/or data entry/correction online via a password-protected interface. Databaseaccess is free of charge and there are no registration requirements for data querying. FINDbase provides a simple, web-based system for population-based mutation data collection and retrieval and can serve not only as a valuable online tool for molecular genetic testing of inherited disorders but also as a non-profit model for sustainable database funding, in the form of a 'database-journal'.

  13. Genetic patterns of domestication in pigeonpea (Cajanus cajan (L.) Millsp.) and wild Cajanus relatives.

    Science.gov (United States)

    Kassa, Mulualem T; Penmetsa, R Varma; Carrasquilla-Garcia, Noelia; Sarma, Birinchi K; Datta, Subhojit; Upadhyaya, Hari D; Varshney, Rajeev K; von Wettberg, Eric J B; Cook, Douglas R

    2012-01-01

    Pigeonpea (Cajanus cajan) is an annual or short-lived perennial food legume of acute regional importance, providing significant protein to the human diet in less developed regions of Asia and Africa. Due to its narrow genetic base, pigeonpea improvement is increasingly reliant on introgression of valuable traits from wild forms, a practice that would benefit from knowledge of its domestication history and relationships to wild species. Here we use 752 single nucleotide polymorphisms (SNPs) derived from 670 low copy orthologous genes to clarify the evolutionary history of pigeonpea (79 accessions) and its wild relatives (31 accessions). We identified three well-supported lineages that are geographically clustered and congruent with previous nuclear and plastid sequence-based phylogenies. Among all species analyzed Cajanus cajanifolius is the most probable progenitor of cultivated pigeonpea. Multiple lines of evidence suggest recent gene flow between cultivated and non-cultivated forms, as well as historical gene flow between diverged but sympatric species. Evidence supports that primary domestication occurred in India, with a second and more recent nested population bottleneck focused in tropical regions that is the likely consequence of pigeonpea breeding. We find abundant allelic variation and genetic diversity among the wild relatives, with the exception of wild species from Australia for which we report a third bottleneck unrelated to domestication within India. Domesticated C. cajan possess 75% less allelic diversity than the progenitor clade of wild Indian species, indicating a severe "domestication bottleneck" during pigeonpea domestication.

  14. [Influences of genetic and environmental factors on smoking related behaviors among male twin adults in China].

    Science.gov (United States)

    Bao, Z Q; Yu, C Q; Wang, B Q; Cao, W H; Gao, W J; Lyu, J; Wang, S F; Pang, Z C; Cong, L M; Dong, Z; Wu, F; Wang, H; Wu, X P; Wang, D Z; Wang, X J; Wang, B Y; Li, L M

    2016-05-01

    To analyze the influences of genetic and environmental factors on smoking behavior, smoking cessation and onset age of smoking less than 20 years in male twin adults. A face-to-face questionnaire was conducted to collect data from 6 458 pair male twins aged ≥25 years registered in 9 provinces(municipality)in China. The heritability of three smoking related behaviors were calculated by using structural equation models. The ACE models were the best models of the three dimensions of smoking, i.e. smoking behavior, smoking cessation and onset age of smoking less than 20 years for male twins, and the corresponding heritability of these behaviors were 0.26(0.19-0.34), 0.27(0.19-0.37)and 0.05(0.00-0.14), respectively. When adjusted for area and age, the heritability of these three behaviors were 0.26(0.19-0.34), 0.31(0.00-0.74)and 0.05(0.00-0.14), respectively. All the three smoking related behaviors were affected by genetic factors, but environment factors had more effect on them. For smoking cessation, the heritability was highest, but the influence of environmental factors was lowest. Meanwhile, for onset age of smoking, the influence of environmental factors was highest.

  15. The relative contribution of environmental and genetic factors to phenotypic variation in familial Mediterranean fever (FMF).

    Science.gov (United States)

    Ben-Zvi, Ilan; Brandt, Benny; Berkun, Yackov; Lidar, Merav; Livneh, Avi

    2012-01-10

    Familial Mediterranean fever (FMF) is an autosomal recessive disease, caused by mutations in the FMF gene MEFV (MEditerranean FeVer). It has a large phenotypic diversity even in patients with similar genotypes. Despite evidence that environmental factors (EFs) and genetic factors, including MEFV mutations (such as M694V, E148Q) and background modifier genes (MGs), affect the clinical manifestations of FMF, the relative contribution of each remains unknown. To investigate the relative contribution of environmental and genetic factors to the phenotype of FMF, we compared the intra-pair clinical concordance of 10 mono and 7 dizygotic twins with FMF. The part played by EFs was determined by the phenotypic discordance of the monozygous twins, and the MGs effect was determined by deducing the environmental effect, computed for MZ twins, from the phenotypic discordance of the dizygous twins. The mean±SD of intra-pair concordance was higher in the MZ than in DZ twin group (88.1±13.2 vs. 70.7±14.1 respectively, P valueFMF is estimated as 11.9%±6.6% and the MGs effect as 17.4%±15.5% in average. In FMF the phenotype is affected by MEFV mutations, MGs and EFs in an estimated ratio of about 6:1.5:1 respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Phylogeny and prediction of genetic similarity of Cronobacter and related taxa by multilocus sequence analysis (MLSA).

    Science.gov (United States)

    Kuhnert, Peter; Korczak, Bozena M; Stephan, Roger; Joosten, Han; Iversen, Carol

    2009-12-31

    Multilocus sequence analysis (MLSA) based on recN, rpoA and thdF genes was done on more than 30 species of the family Enterobacteriaceae with a focus on Cronobacter and the related genus Enterobacter. The sequences provide valuable data for phylogenetic, taxonomic and diagnostic purposes. Phylogenetic analysis showed that the genus Cronobacter forms a homogenous cluster related to recently described species of Enterobacter, but distant to other species of this genus. Combining sequence information on all three genes is highly representative for the species' %GC-content used as taxonomic marker. Sequence similarity of the three genes and even of recN alone can be used to extrapolate genetic similarities between species of Enterobacteriaceae. Finally, the rpoA gene sequence, which is the easiest one to determine, provides a powerful diagnostic tool to identify and differentiate species of this family. The comparative analysis gives important insights into the phylogeny and genetic relatedness of the family Enterobacteriaceae and will serve as a basis for further studies and clarifications on the taxonomy of this large and heterogeneous family.

  17. Interaction between genetic predisposition to obesity and dietary calcium in relation to subsequent change in body weight and waist circumference

    DEFF Research Database (Denmark)

    Larsen, Sofus C; Ängquist, Lars Henrik; Ahluwalia, Tarunveer Singh

    2014-01-01

    Studies indicate an effect of dietary calcium on change in body weight (BW) and waist circumference (WC), but the results are inconsistent. Furthermore, a relation could depend on genetic predisposition to obesity.......Studies indicate an effect of dietary calcium on change in body weight (BW) and waist circumference (WC), but the results are inconsistent. Furthermore, a relation could depend on genetic predisposition to obesity....

  18. Nuclear and cytoplasmic genetic diversity in weed beet and sugar beet accessions compared to wild relatives: new insights into the genetic relationships within the Beta vulgaris complex species.

    Science.gov (United States)

    Fénart, Stéphane; Arnaud, Jean-François; De Cauwer, Isabelle; Cuguen, Joël

    2008-05-01

    Hybridization between cultivated species and their wild relatives is now widely considered to be common. In the Beta vulgaris complex, the sugar beet seed multiplication areas have been the scene of inadvertent pollination of sugar beet seed bearers by wild ruderal pollen donors, generating a weedy form of beet which infests sugar beet fields in European countries. Up to now, investigations of evolutionary dynamics of genetic diversity within the B. vulgaris complex were addressed using few genetical markers and few accessions. In this study, we tackled this issue using a panel of complementary markers: five nuclear microsatellite loci, four mitochondrial minisatellite loci and one chloroplastic PCR-RFLP marker. We sampled 1,640 individuals that illustrate the actual distribution of inland ruderal beets of South Western France, weed beets and wild sea beets of northern France as well as the diversity of 35 contemporary European diploid cultivars. Nuclear genetic diversity in weed beets appeared to be as high as those of ruderal beets and sea beets, whereas the narrowness of cultivar accessions was confirmed. This genetic bottleneck in cultivars is even more important in the cytoplasmic genome as only one haplotype was found among all sugar beet cultivars. The large majority of weed beet populations also presented this unique cytoplasmic haplotype, as expected owing to their maternal cultivated origin. Nonetheless, various cytoplasmic haplotypes were found within three populations of weed beets, implying wild-to-weed seed flows. Finally, our findings gave new insights into the genetical relationships between the components of the B. vulgaris complex: (1) we found a very strong genetic divergence between wild sea beet and other relatives, which was unexpected given the recent evolutionary history and the full cross-compatibility of all taxa and (2) we definitely confirmed that the classification into cultivated, wild, ruderal and weed forms according to their

  19. Development of RNA Interference Trigger-Mediated Gene Silencing in Entamoeba invadens.

    Science.gov (United States)

    Suresh, Susmitha; Ehrenkaufer, Gretchen; Zhang, Hanbang; Singh, Upinder

    2016-04-01

    Entamoeba histolytica, a protozoan parasite, is an important human pathogen and a leading parasitic cause of death. The organism has two life cycle stages, trophozoites, which are responsible for tissue invasion, and cysts, which are involved in pathogen transmission. Entamoeba invadens is the model system to study Entamoeba developmental biology, as high-grade regulated encystation and excystation are readily achievable. However, the lack of gene-silencing tools in E. invadens has limited the molecular studies that can be performed. Using the endogenous RNA interference (RNAi) pathway in Entamoeba, we developed an RNAi-based trigger gene-silencing approach inE. invadens We demonstrate that a gene's coding region that has abundant antisense small RNAs (sRNAs) can trigger silencing of a gene that is fused to it. The trigger fusion leads to the generation of abundant antisense sRNAs that map to the target gene, with silencing occurring independently of trigger location at the 5' or 3' end of a gene. Gene silencing is stably maintained during development, including encystation and excystation. We have used this approach to successfully silence two E. invadens genes: a putative rhomboid protease gene and a SHAQKY family Myb gene. The Myb gene is upregulated during oxidative stress and development, and its downregulation led, as predicted, to decreased viability under oxidative stress and decreased cyst formation. Thus, the RNAi trigger silencing method can be used to successfully investigate the molecular functions of genes inE. invadens Dissection of the molecular basis of Entamoeba stage conversion is now possible, representing an important technical advance for the system.

  20. Preliminary Analysis on the Relative Solution Space Sizes for MTSP with Genetic Algorithm

    Science.gov (United States)

    Hao, Junling

    It is well known that the chromosome design is pivotal to solve the multiple traveling salesman problems with genetic algorithm. A well-designed chromosome coding can eliminate or reduce the redundant solutions. One chromosome and two chromosome design methods and a recently proposed two-part chromosome design are firstly introduced in this paper. Then the preliminary quantitative comparison analysis of the solution spaces of three different chromosome design methods is presented when the number of cities is linear with the travelers. The concept of relative solution space is proposed in order to compare the relative size of the solution spaces. The solution space of two-part chromosome design is much smaller than those of the traditional chromosome design. The result given in this paper provides a good guideline for the possible algorithmic design and engineering applications.

  1. Intellectual property rights related to the genetically modified glyphosate tolerant soybeans in Brazil.

    Science.gov (United States)

    Rodrigues, Roberta L; Lage, Celso L S; Vasconcellos, Alexandre G

    2011-06-01

    The present work analyzes the different modalities of protection of the intellectual creations in the biotechnology agricultural field. Regarding the Brazilian legislations related to the theme (the Industrial Property Law - no. 9. 279/96 and the Plant Variety Protection Law - no. 9. 456/97), and based in the international treaties signed by Brazil, the present work points to the inclusions of each of them, as well as to their interfaces using as reference the case study of glyphosate tolerant genetically modified soybean. For this case study, Monsanto's pipelines patents were searched and used to analyze the limits of patent protection in respect to others related to the Intellectual Property (IP) laws. Thus, it was possible to elucidate the complex scenario of the Intellectual Property of the glyphosate tolerant soybeans, since for the farmer it is hard to correlate the royalties payment with the IP enterprise's rights.

  2. Can genetic risk information for age-related macular degeneration influence motivation to stop smoking? A pilot study.

    Science.gov (United States)

    Rennie, C A; Stinge, A; King, E A; Sothirachagan, S; Osmond, C; Lotery, A J

    2012-01-01

    Smoking can increase the risk of macular degeneration and this is more than additive if a person also has a genetic risk. The purpose of this study was to examine whether knowledge of genetic risk for age-related macular degeneration (AMD) could influence motivation to quit smoking. A questionnaire-based study of hypothetical case scenarios given to 49 smokers without AMD. Participants were randomly allocated to a generic risk, high genetic risk, or low genetic risk of developing AMD scenario. Forty-seven percent knew of the link between smoking and eye disease. In all, 76%, 67%, and 46% for the high risk, generic, and low risk groups, respectively, would rethink quitting (P for trend = 0.082). In all, 67%, 40%, and 38.5%, respectively, would be likely, very likely, or would definitely quit in the following month (P for trend = 0.023). Few participants (smoking session with no difference across groups. In all, 75.5% of participants would consider taking a genetic test for AMD. In this pilot study, a trend was seen for the group given high genetic risk information to be more likely to quit than the generic or low genetic risk groups. Participants were willing to take a genetic test but further work is needed to address the cost benefits of routine genetic testing for risk of AMD. More generic risk information should be given to the public, and health warnings on cigarette packets that 'smoking causes blindness' is a good way to achieve this.

  3. Transcriptional profile of the homologous recombination machinery and characterization of the EhRAD51 recombinase in response to DNA damage in Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    López-Camarillo César

    2008-04-01

    Full Text Available Abstract Background In eukaryotic and prokaryotic cells, homologous recombination is an accurate mechanism to generate genetic diversity, and it is also used to repair DNA double strand-breaks. RAD52 epistasis group genes involved in recombinational DNA repair, including mre11, rad50, nsb1/xrs2, rad51, rad51c/rad57, rad51b/rad55, rad51d, xrcc2, xrcc3, rad52, rad54, rad54b/rdh54 and rad59 genes, have been studied in human and yeast cells. Notably, the RAD51 recombinase catalyses strand transfer between a broken DNA and its undamaged homologous strand, to allow damaged region repair. In protozoan parasites, homologous recombination generating antigenic variation and genomic rearrangements is responsible for virulence variation and drug resistance. However, in Entamoeba histolytica the protozoan parasite responsible for human amoebiasis, DNA repair and homologous recombination mechanisms are still unknown. Results In this paper, we initiated the study of the mechanism for DNA repair by homologous recombination in the primitive eukaryote E. histolytica using UV-C (150 J/m2 irradiated trophozoites. DNA double strand-breaks were evidenced in irradiated cells by TUNEL and comet assays and evaluation of the EhH2AX histone phosphorylation status. In E. histolytica genome, we identified genes homologous to yeast and human RAD52 epistasis group genes involved in DNA double strand-breaks repair by homologous recombination. Interestingly, the E. histolytica RAD52 epistasis group related genes were differentially expressed before and after UV-C treatment. Next, we focused on the characterization of the putative recombinase EhRAD51, which conserves the typical architecture of RECA/RAD51 proteins. Specific antibodies immunodetected EhRAD51 protein in both nuclear and cytoplasmic compartments. Moreover, after DNA damage, EhRAD51 was located as typical nuclear foci-like structures in E. histolytica trophozoites. Purified recombinant EhRAD51 exhibited DNA binding

  4. IN VITRO STUDY OF ENTAMOEBA HISTOLYTICA CAUSATIVE AGENT OF AMOEBIASIS WITH LEMON JUICE AT DIFFERENT CONCENTRATION SHOWED ANTIAMOEBIC PROPERTIES

    Directory of Open Access Journals (Sweden)

    Shrivastava Bhanu

    2011-09-01

    Full Text Available A species of parasite protozoa Entamoeba histolytica causing amoebiasis and amoebic dysentery characteristic include a single nucleus containing a small central karyosome and peripheral chromatin that is finely and regularly beaded. This is a single celled parasitic animal, that infects predominantly humans and other primates. Amoebic infection was first described by Fedor Losch in 1875 in St. Petersburg. In 1890, Sir William Osler reported the first North American case of amoebiasis when he observed amoebae in stool in abscess fluid from physician who previously resided in Panama. So we used the Lemon juice (Citrus at different concentration against Entamoeba histolytica to treat the amoebiasis disease. Entamoeba histolytica shows the variety of growth due to the effect of Lemon juice (Citrus. Lemon juice is ingredient and it has antiamoebic properties against Entamoeba histolytica a causative agent of amoebiasis.

  5. Tumors that Mimic Asbestos-Related Mesothelioma: Time to Consider a Genetics-Based Tumor Registry?

    Directory of Open Access Journals (Sweden)

    Brent Daniel Kerger

    2014-05-01

    Full Text Available The diagnosis of mesothelioma is not always straightforward, despite known immunohistochemical markers and other diagnostic techniques. One reason for the difficulty is that extrapleural tumors resembling mesothelioma may have several possible etiologies, especially in cases with no meaningful history of amphibole asbestos exposure. When the diagnosis of mesothelioma is based on histologic features alone, primary mesotheliomas may resemble various primary or metastatic cancers that have directly invaded the serosal membranes. Some of these metastatic malignancies, particularly carcinomas and sarcomas of the pleura, pericardium and peritoneum, may undergo desmoplastic reaction in the pleura, thereby mimicking mesothelioma, rather than the primary tumor. Encasement of the lung by direct spread or metastasis, termed pseudomesotheliomatous spread, occurs with several other primary cancer types, including certain late-stage tumors from genetic cancer syndromes exhibiting chromosomal instability. Although immunohistochemical staining patterns differentiate most carcinomas, lymphomas, and mestastatic sarcomas from mesotheliomas, specific genetic markers in tumor or somatic tissues have been recently identified that may also distinguish these tumor types from asbestos-related mesothelioma. A registry for genetic screening of mesothelioma cases would help lead to improvements in diagnostic criteria, prognostic accuracy and treatment efficacy, as well as improved estimates of primary mesothelioma incidence and of background rates of cancers unrelated to asbestos that might be otherwise mistaken for mesothelioma. This information would also help better define the dose-response relationships for mesothelioma and asbestos exposure, as well as other risk factors for mesothelioma and other mesenchymal or advanced metastatic tumors that may be indistinguishable by histology and staining characteristics.

  6. Mongolians in the Genetic Landscape of Central Asia: Exploring the Genetic Relations among Mongolians and Other World Populations.

    Science.gov (United States)

    Brissenden, Jane E; Kidd, Judith R; Evsanaa, Baigalmaa; Togtokh, Ariunaa J; Pakstis, Andrew J; Friedlaender, Françoise; Kidd, Kenneth K; Roscoe, Janet M

    2015-04-01

    Genetic data on North and Central Asian populations are underrepresented in the literature, especially for autosomal markers. In the present study we used 812 single nucleotide polymorphisms (SNPs) distributed across all the human autosomes and extensively studied at Yale to examine the affinities of two recently collected samples of populations: rural and cosmopolitan Mongolians from Ulaanbaatar and nomadic, Turkic-speaking Tsaatan from Mongolia near the Siberian border. We compare these two populations with each other and with a global set of populations and discuss their relationships to New World populations. Specifically, we analyze data on 521 autosomal loci (single SNPs and multi-SNP haplotypes) studied in 57 populations representing all the major geographical regions of the world. We conclude that these North and Central Asian populations are genetically distinct from all other populations in our study and may be close to the ancestral lineage leading to the New World populations.

  7. Risk factors for Entamoeba histolytica infection in an agricultural community in Hanam province, Vietnam

    Directory of Open Access Journals (Sweden)

    Nguyen-Viet Hung

    2011-06-01

    Full Text Available Abstract Background Entamoeba histolytica is an important protozoan intestinal infection in resource-poor settings, including Vietnam. The study objective was to assess risk factors of E. histolytica infection in a community in Vietnam, where wastewater and human excreta are used in agriculture. A case-control study was conducted among residents of Hanam province, Northern Vietnam. Cases (n = 46 infected with E. histolytica and non-infected controls (n = 138 were identified in a cross-sectional survey among 794 randomly selected individuals and matched for age, sex and place of residence. Potential risk factors including exposure to human and animal excreta and household wastewater were assessed with a questionnaire. Results People from households with an average socio-economic status had a much higher risk of E. histolytica infection (odds ratio [OR]=4.3, 95% confidence interval [CI]: 1.3-14.0 compared with those from households with a good socioeconomic status. Those individuals who never or rarely used soap for hand washing had a 3.4 times higher risk for infection (OR=3.4, 95% CI: 1.1-10.0, compared to those who used always soap. In contrast, none of the factors related to use of human or animal excreta was statistically significant associated with E. histolytica infection. People having close contact with domestic animals presented a greater risk of E. histolytica infection (OR = 5.9, 95% CI: 1.8-19.0 than those without animal contact. E. histolytica infection was not associated with direct contact with Nhue river water, pond water and household's sanitary conditions, type of latrine or water source used. Conclusions Our study suggests that in settings where human and animal excreta and Nhue River water are intensively used in agriculture, socio-economic and personal hygiene factors determine infection with E. histolytica, rather than exposure to human and animal excreta in agricultural activities.

  8. Identification of phosphatidylcholine transfer protein-like in the parasite Entamoeba histolytica.

    Science.gov (United States)

    Piña-Vázquez, Carolina; Reyes-López, Magda; Mendoza-Hernández, Guillermo; Bermúdez-Cruz, Rosa María; de la Garza, Mireya

    2014-12-01

    Caveolin is the protein marker of caveola-mediated endocytosis. Previously, we demonstrated by immunoblotting and immunofluorescence that an anti-chick embryo caveolin-1 monoclonal antibody (mAb) recognizes a protein in amoeba extracts. Nevertheless, the caveolin-1 gene is absent in the Entamoeba histolytica genome database. In this work, the goal was to isolate, identify and characterize the protein that cross-reacts with chick embryo caveolin-1. We identified the protein using a proteomic approach, and the complete gene was cloned and sequenced. The identified protein, E. histolytica phosphatidylcholine transfer protein-like (EhPCTP-L), is a member of the StAR-related lipid transfer (START) protein superfamily. The human homolog binds and transfers phosphatidylcholine (PC) and phosphatidylethanolamine (PE) between model membranes in vitro; however, the physiological role of PCTP-L remains elusive. Studies in silico showed that EhPCTP-L has a central START domain and also contains a C-terminal intrinsically disordered region. The anti-rEhPCTP-L antibody demonstrated that EhPCTP-L is found in the plasma membrane and cytosol, which is in agreement with previous reports on the human counterpart. This result points to the plasma membrane as one possible target membrane for EhPCTP-L. Furthermore, assays using filipin and nystatin showed down regulation of EhPCTP-L, in an apparently cholesterol-independent way. Interestingly, EhPCTP-L binds primarily to anionic phospholipids phosphatidylserine (PS) and phosphatidic acid (PA), while its mammalian counterpart HsPCTP-L binds neutral phospholipids PC and PE. The present study provides information that helps reveal the possible function and regulation of PCTP-L expression in the primitive eukaryotic parasite E. histolytica.

  9. Unique Structural and Nucleotide Exchange Features of the Rho1 GTPase of Entamoeba histolytica*

    Science.gov (United States)

    Bosch, Dustin E.; Wittchen, Erika S.; Qiu, Connie; Burridge, Keith; Siderovski, David P.

    2011-01-01

    The single-celled human parasite Entamoeba histolytica possesses a dynamic actin cytoskeleton vital for its intestinal and systemic pathogenicity. The E. histolytica genome encodes several Rho family GTPases known to regulate cytoskeletal dynamics. EhRho1, the first family member identified, was reported to be insensitive to the Rho GTPase-specific Clostridium botulinum C3 exoenzyme, raising the possibility that it may be a misclassified Ras family member. Here, we report the crystal structures of EhRho1 in both active and inactive states. EhRho1 is activated by a conserved switch mechanism, but diverges from mammalian Rho GTPases in lacking a signature Rho insert helix. EhRho1 engages a homolog of mDia, EhFormin1, suggesting a role in mediating serum-stimulated actin reorganization and microtubule formation during mitosis. EhRho1, but not a constitutively active mutant, interacts with a newly identified EhRhoGDI in a prenylation-dependent manner. Furthermore, constitutively active EhRho1 induces actin stress fiber formation in mammalian fibroblasts, thereby identifying it as a functional Rho family GTPase. EhRho1 exhibits a fast rate of nucleotide exchange relative to mammalian Rho GTPases due to a distinctive switch one isoleucine residue reminiscent of the constitutively active F28L mutation in human Cdc42, which for the latter protein, is sufficient for cellular transformation. Nonconserved, nucleotide-interacting residues within EhRho1, revealed by the crystal structure models, were observed to contribute a moderating influence on fast spontaneous nucleotide exchange. Collectively, these observations indicate that EhRho1 is a bona fide member of the Rho GTPase family, albeit with unique structural and functional aspects compared with mammalian Rho GTPases. PMID:21930699

  10. Unique structural and nucleotide exchange features of the Rho1 GTPase of Entamoeba histolytica.

    Science.gov (United States)

    Bosch, Dustin E; Wittchen, Erika S; Qiu, Connie; Burridge, Keith; Siderovski, David P

    2011-11-11

    The single-celled human parasite Entamoeba histolytica possesses a dynamic actin cytoskeleton vital for its intestinal and systemic pathogenicity. The E. histolytica genome encodes several Rho family GTPases known to regulate cytoskeletal dynamics. EhRho1, the first family member identified, was reported to be insensitive to the Rho GTPase-specific Clostridium botulinum C3 exoenzyme, raising the possibility that it may be a misclassified Ras family member. Here, we report the crystal structures of EhRho1 in both active and inactive states. EhRho1 is activated by a conserved switch mechanism, but diverges from mammalian Rho GTPases in lacking a signature Rho insert helix. EhRho1 engages a homolog of mDia, EhFormin1, suggesting a role in mediating serum-stimulated actin reorganization and microtubule formation during mitosis. EhRho1, but not a constitutively active mutant, interacts with a newly identified EhRhoGDI in a prenylation-dependent manner. Furthermore, constitutively active EhRho1 induces actin stress fiber formation in mammalian fibroblasts, thereby identifying it as a functional Rho family GTPase. EhRho1 exhibits a fast rate of nucleotide exchange relative to mammalian Rho GTPases due to a distinctive switch one isoleucine residue reminiscent of the constitutively active F28L mutation in human Cdc42, which for the latter protein, is sufficient for cellular transformation. Nonconserved, nucleotide-interacting residues within EhRho1, revealed by the crystal structure models, were observed to contribute a moderating influence on fast spontaneous nucleotide exchange. Collectively, these observations indicate that EhRho1 is a bona fide member of the Rho GTPase family, albeit with unique structural and functional aspects compared with mammalian Rho GTPases.

  11. Unique Structural and Nucleotide Exchange Features of the Rho1 GTPase of Entamoeba histolytica

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, Dustin E.; Wittchen, Erika S.; Qiu, Connie; Burridge, Keith; Siderovski, David P. (UNC)

    2012-08-10

    The single-celled human parasite Entamoeba histolytica possesses a dynamic actin cytoskeleton vital for its intestinal and systemic pathogenicity. The E. histolytica genome encodes several Rho family GTPases known to regulate cytoskeletal dynamics. EhRho1, the first family member identified, was reported to be insensitive to the Rho GTPase-specific Clostridium botulinum C3 exoenzyme, raising the possibility that it may be a misclassified Ras family member. Here, we report the crystal structures of EhRho1 in both active and inactive states. EhRho1 is activated by a conserved switch mechanism, but diverges from mammalian Rho GTPases in lacking a signature Rho insert helix. EhRho1 engages a homolog of mDia, EhFormin1, suggesting a role in mediating serum-stimulated actin reorganization and microtubule formation during mitosis. EhRho1, but not a constitutively active mutant, interacts with a newly identified EhRhoGDI in a prenylation-dependent manner. Furthermore, constitutively active EhRho1 induces actin stress fiber formation in mammalian fibroblasts, thereby identifying it as a functional Rho family GTPase. EhRho1 exhibits a fast rate of nucleotide exchange relative to mammalian Rho GTPases due to a distinctive switch one isoleucine residue reminiscent of the constitutively active F28L mutation in human Cdc42, which for the latter protein, is sufficient for cellular transformation. Nonconserved, nucleotide-interacting residues within EhRho1, revealed by the crystal structure models, were observed to contribute a moderating influence on fast spontaneous nucleotide exchange. Collectively, these observations indicate that EhRho1 is a bona fide member of the Rho GTPase family, albeit with unique structural and functional aspects compared with mammalian Rho GTPases.

  12. Endoplasmic reticulum stress-sensing mechanism is activated in Entamoeba histolytica upon treatment with nitric oxide.

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    Julien Santi-Rocca

    Full Text Available The Endoplasmic Reticulum stores calcium and is a site of protein synthesis and modification. Changes in ER homeostasis lead to stress responses with an activation of the unfolded protein response (UPR. The Entamoeba histolytica endomembrane system is simple compared to those of higher eukaryotes, as a canonical ER is not observed. During amoebiasis, an infection of the human intestine and liver by E. histolytica, nitric oxide (NO triggers an apoptotic-like event preceded by an impairment of energy production and a loss of important parasite pathogenic features. We address the question of how this ancient eukaryote responds to stress induced by immune components (i.e. NO and whether stress leads to ER changes and subsequently to an UPR. Gene expression analysis suggested that NO triggers stress responses marked by (i dramatic up-regulation of hsp genes although a bona fide UPR is absent; (ii induction of DNA repair and redox gene expression and iii up-regulation of glycolysis-related gene expression. Enzymology approaches demonstrate that NO directly inhibits glycolysis and enhance cysteine synthase activity. Using live imaging and confocal microscopy we found that NO dramatically provokes extensive ER fragmentation. ER fission in E. histolytica appears as a protective response against stress, as it has been recently proposed for neuron self-defense during neurologic disorders. Chronic ER stress is also involved in metabolic diseases including diabetes, where NO production reduces ER calcium levels and activates cell death. Our data highlighted unique cellular responses of interest to understand the mechanisms of parasite death during amoebiasis.

  13. Resistance to intestinal Entamoeba histolytica infection is conferred by innate immunity and Gr-1+ cells.

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    Asgharpour, Amon; Gilchrist, Carol; Baba, Duza; Hamano, Shinjiro; Houpt, Eric

    2005-08-01

    Establishment of intestinal infection with Entamoeba histolytica depends on the mouse strain; C57BL/6 mice are highly resistant, and C3H/HeJ mice are relatively susceptible. We found that resistance to intestinal infection was independent of lymphocyte activity or H-2 haplotype and occurred in the first hours to days postchallenge according to in vivo imaging. At 18 h postchallenge, the ceca of resistant C57BL/6 mice were histologically unremarkable, in contrast to the severe inflammation observed in susceptible C3H/HeJ mice. Comparison of cecal gene expression in C3H/HeJ and C57BL/6 mice demonstrated that there was parasite-induced upregulation of proinflammatory and neutrophil chemotaxis transcripts and there was downregulation of transforming growth factor beta signaling molecules. Pretreatment with dexamethasone abrogated the partial resistance of C3H/HeJ or CBA mice through an innate, lymphocyte-independent mechanism, but it had no effect on the high-level resistance of C57BL/6 mice. Similarly, administration of a neutrophil-depleting anti-Gr-1 monoclonal antibody (RB6-8C5) decreased the partial resistance of CBA mice and led to severe pathology compared to control antibody-treated mice, but it had no effect on C57BL/6 resistance. These data indicate that there are discrete mechanisms of innate resistance to E. histolytica depending on the host background and, in contrast to other reports, imply that neutrophils are protective and not damaging in intestinal amebiasis.

  14. Transcriptional silencing of multiple genes in trophozoites of Entamoeba histolytica.

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    Rivka Bracha

    2006-05-01

    Full Text Available In a previous work we described the transcriptional silencing of the amoebapore A (AP-A gene (Ehap-a of Entamoeba histolytica strain HM-1:IMSS. The silencing occurred following transfection with a plasmid containing a 5' upstream region (473 bp of Ehap-a that included a truncated segment (140 bp of a short interspersed nuclear element (SINE1. Silencing remained in effect even after removal of the plasmid (clone G3. Neither short interfering RNA nor methylated DNA were detected, but the chromatin domain of Ehap-a in the gene-silenced trophozoites was modified. Two other similar genes (Ehap-b and one encoding a Saposin-like protein, SAPLIP 1 also became silenced. In the present work we demonstrate the silencing of a second gene of choice, one that encodes the light subunit of the Gal/GalNAc inhibitable lectin (Ehlgl1 and the other, the cysteine proteinase 5 (EhCP-5. This silencing occurred in G3 trophozoites transfected with a plasmid in which the 473 bp 5' upstream Ehap-a fragment was directly ligated to the second gene. Transcriptional silencing occurred in both the transgene and the chromosomal gene. SINE1 sequences were essential, as was a direct connection between the Ehap-a upstream region and the beginning of the open reading frame of the second gene. Gene silencing did not occur in strain HM-1:IMSS with any of these plasmid constructs. The trophozoites with two silenced genes were virulence-attenuated as were those of clone G3. In addition, trophozoites not expressing Lgl1 and AP-A proteins had a significantly reduced ability to cap the Gal/GalNAc-lectin to the uroid region when incubated with antibodies against the heavy (170 kDa subunit of the lectin. Lysates of trophozoites lacking cysteine proteinase 5 and AP-A proteins had 30% less cysteine proteinase activity than those of HM-1:IMSS strain or the G3 clone. Silencing of other genes in G3 amoebae could provide a model to study their various functions. In addition, double gene

  15. Transcriptional silencing of multiple genes in trophozoites of Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    2006-05-01

    Full Text Available In a previous work we described the transcriptional silencing of the amoebapore A (AP-A gene (Ehap-a of Entamoeba histolytica strain HM-1:IMSS. The silencing occurred following transfection with a plasmid containing a 5' upstream region (473 bp of Ehap-a that included a truncated segment (140 bp of a short interspersed nuclear element (SINE1. Silencing remained in effect even after removal of the plasmid (clone G3. Neither short interfering RNA nor methylated DNA were detected, but the chromatin domain of Ehap-a in the gene-silenced trophozoites was modified. Two other similar genes (Ehap-b and one encoding a Saposin-like protein, SAPLIP 1 also became silenced. In the present work we demonstrate the silencing of a second gene of choice, one that encodes the light subunit of the Gal/GalNAc inhibitable lectin (Ehlgl1 and the other, the cysteine proteinase 5 (EhCP-5. This silencing occurred in G3 trophozoites transfected with a plasmid in which the 473 bp 5' upstream Ehap-a fragment was directly ligated to the second gene. Transcriptional silencing occurred in both the transgene and the chromosomal gene. SINE1 sequences were essential, as was a direct connection between the Ehap-a upstream region and the beginning of the open reading frame of the second gene. Gene silencing did not occur in strain HM-1:IMSS with any of these plasmid constructs. The trophozoites with two silenced genes were virulence-attenuated as were those of clone G3. In addition, trophozoites not expressing Lgl1 and AP-A proteins had a significantly reduced ability to cap the Gal/GalNAc-lectin to the uroid region when incubated with antibodies against the heavy (170 kDa subunit of the lectin. Lysates of trophozoites lacking cysteine proteinase 5 and AP-A proteins had 30% less cysteine proteinase activity than those of HM-1:IMSS strain or the G3 clone. Silencing of other genes in G3 amoebae could provide a model to study their various functions. In addition, double gene

  16. Characterization of the Entamoeba histolytica ornithine decarboxylase-like enzyme.

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    Anupam Jhingran

    Full Text Available BACKGROUND: The polyamines putrescine, spermidine, and spermine are organic cations that are required for cell growth and differentiation. Ornithine decarboxylase (ODC, the first and rate-limiting enzyme in the polyamine biosynthetic pathway, is a highly regulated enzyme. METHODOLOGY AND RESULTS: To use this enzyme as a potential drug target, the gene encoding putative ornithine decarboxylase (ODC-like sequence was cloned from Entamoeba histolytica, a protozoan parasite causing amoebiasis. DNA sequence analysis revealed an open reading frame (ORF of approximately 1,242 bp encoding a putative protein of 413 amino acids with a calculated molecular mass of 46 kDa and a predicted isoelectric point of 5.61. The E. histolytica putative ODC-like sequence has 33% sequence identity with human ODC and 36% identity with the Datura stramonium ODC. The ORF is a single-copy gene located on a 1.9-Mb chromosome. The recombinant putative ODC protein (48 kDa from E. histolytica was heterologously expressed in Escherichia coli. Antiserum against recombinant putative ODC protein detected a band of anticipated size approximately 46 kDa in E. histolytica whole-cell lysate. Difluoromethylornithine (DFMO, an enzyme-activated irreversible inhibitor of ODC, had no effect on the recombinant putative ODC from E. histolytica. Comparative modeling of the three-dimensional structure of E. histolytica putative ODC shows that the putative binding site for DFMO is disrupted by the substitution of three amino acids-aspartate-332, aspartate-361, and tyrosine-323-by histidine-296, phenylalanine-305, and asparagine-334, through which this inhibitor interacts with the protein. Amino acid changes in the pocket of the E. histolytica enzyme resulted in low substrate specificity for ornithine. It is possible that the enzyme has evolved a novel substrate specificity. CONCLUSION: To our knowledge this is the first report on the molecular characterization of putative ODC-like sequence from

  17. Entamoeba histolytica-Encoded Homolog of Macrophage Migration Inhibitory Factor Contributes to Mucosal Inflammation during Amebic Colitis.

    Science.gov (United States)

    Ngobeni, Renay; Abhyankar, Mayuresh M; Jiang, Nona M; Farr, Laura A; Samie, Amidou; Haque, Rashidul; Moonah, Shannon N

    2017-04-15

    Understanding the mechanisms by which Entamoeba histolytica drives gut inflammation is critical for the development of improved preventive and therapeutic strategies. E. histolytica encodes a homolog of the human cytokine macrophage migration inhibitory factor (MIF). Here, we investigated the role of E. histolytica MIF (EhMIF) during infection. We found that the concentration of fecal EhMIF correlated with the level of intestinal inflammation in persons with intestinal amebiasis. Mice treated with antibodies that specifically block EhMIF had reduced chemokine expression and neutrophil infiltration in the mucosa. In addition to antibody-mediated neutralization, we used a genetic approach to test the effect of EhMIF on mucosal inflammation. Mice infected with parasites overexpressing EhMIF had increased chemokine expression, neutrophil influx, and mucosal damage. Together, these results uncover a specific parasite protein that increases mucosal inflammation, expands our knowledge of host-parasite interaction during amebic colitis, and highlights a potential immunomodulatory target. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  18. Microbes and microbial toxins: paradigms for microbial-mucosal interactions. VI. Entamoeba histolytica: parasite-host interactions.

    Science.gov (United States)

    Stanley, S L; Reed, S L

    2001-06-01

    The protozoan intestinal parasite Entamoeba histolytica remains a significant cause of morbidity and mortality worldwide. E. histolytica causes two major clinical syndromes, amebic colitis and amebic liver abscess. Recent advances in the development of in vitro and in vivo models of disease, new genetic approaches, the identification of key E. histolytica virulence factors, and the recognition of crucial elements of the host response to infection have led to significant insights into the pathogenesis of amebic infection. E. histolytica virulence factors include 1) a surface galactose binding lectin that mediates E. histolytica binding to host cells and may contribute to amebic resistance to complement, 2) amebapores, small peptides capable of lysing cells, which may play a role in killing intestinal epithelial cells, hepatocytes, and host defense cells, and 3) a family of secreted cysteine proteinases that play a key role in E. histolytica tissue invasion, evasion of host defenses, and parasite induction of gut inflammation. Amebae can both lyse host cells and induce their suicide through programmed cell death. The host response is also an important factor in the outcome of infection, and neutrophils may play a key role in contributing to the tissue damage seen in amebiasis and in controlling amebic infection.

  19. Identification of an avirulent Entamoeba histolytica strain with unique tRNA-linked short tandem repeat markers.

    Science.gov (United States)

    Escueta-de Cadiz, Aleyla; Kobayashi, Seiki; Takeuchi, Tsutomu; Tachibana, Hiroshi; Nozaki, Tomoyoshi

    2010-03-01

    Highly polymorphic, non-coding short tandem repeats (STR) are scattered between the tRNA genes in Entamoeba histolytica in a unique tandemly arrayed organization. STR markers that correlate with the virulence of individual E. histolytica strains have recently been reported. Here we evaluated the usefulness of tRNA-linked STR loci as genetic markers in identifying virulent and avirulent strains of E. histolytica from 37 Japanese E. histolytica samples (12 diarrheic/dysenteric, 20 amebic liver abscess (ALA), and 5 asymptomatic cases). Twenty three genotypes, assigned by combining the STR sequence types from all 6 STR loci, were identified. One to 8 new STR sequence types per locus were also discovered. Genotypes found in asymptomatic isolates were highly polymorphic (4 out of 5 genotypes were unique to this group), while in symptomatic isolates, almost half of the genotypes were shared between diarrhea/dysentery and ALA. One asymptomatic isolate (KU27) showed unique STR patterns in 4 loci. This strain, though associated with the typical pathogenic zymodeme II, failed to induce amebic liver abscess by animal challenge, which suggests that inherently avirulent E. histolytica strains exist, that are associated with unique genotypes. Furthermore, STR genotyping and in vivo challenge of 2 other asymptomatic isolates (KU14 and KU26) verified the covert virulence of these strains.

  20. JRC GMO-Amplicons: a collection of nucleic acid sequences related to genetically modified organisms.

    Science.gov (United States)

    Petrillo, Mauro; Angers-Loustau, Alexandre; Henriksson, Peter; Bonfini, Laura; Patak, Alex; Kreysa, Joachim

    2015-01-01

    The DNA target sequence is the key element in designing detection methods for genetically modified organisms (GMOs). Unfortunately this information is frequently lacking, especially for unauthorized GMOs. In addition, patent sequences are generally poorly annotated, buried in complex and extensive documentation and hard to link to the corresponding GM event. Here, we present the JRC GMO-Amplicons, a database of amplicons collected by screening public nucleotide sequence databanks by in silico determination of PCR amplification with reference methods for GMO analysis. The European Union Reference Laboratory for Genetically Modified Food and Feed (EU-RL GMFF) provides these methods in the GMOMETHODS database to support enforcement of EU legislation and GM food/feed control. The JRC GMO-Amplicons database is composed of more than 240 000 amplicons, which can be easily accessed and screened through a web interface. To our knowledge, this is the first attempt at pooling and collecting publicly available sequences related to GMOs in food and feed. The JRC GMO-Amplicons supports control laboratories in the design and assessment of GMO methods, providing inter-alia in silico prediction of primers specificity and GM targets coverage. The new tool can assist the laboratories in the analysis of complex issues, such as the detection and identification of unauthorized GMOs. Notably, the JRC GMO-Amplicons database allows the retrieval and characterization of GMO-related sequences included in patents documentation. Finally, it can help annotating poorly described GM sequences and identifying new relevant GMO-related sequences in public databases. The JRC GMO-Amplicons is freely accessible through a web-based portal that is hosted on the EU-RL GMFF website. Database URL: http://gmo-crl.jrc.ec.europa.eu/jrcgmoamplicons/.

  1. Rare chromosomal, genetic, and epigenetic-related risks associated with infertility treatment.

    Science.gov (United States)

    Kurinczuk, Jennifer J; Bhattacharya, Siladitya

    2014-08-01

    This article reviews the rarer chromosomal, genetic, and epigenetic-related risks of adverse child outcomes associated with infertility and its treatment. Excess structural chromosomal anomalies have been found in both male and female partners undergoing infertility treatment, and these risk direct transmission to offspring. Microdeletions of the Y-chromosome associated with male infertility have been transmitted to sons following treatment with intracytoplasmic sperm injection. It is thus possible that male offspring of men with infertility could experience fertility problems in adulthood. Infertility treatment for men with cystic fibrosis, or with congenital bilateral absence of the vas deferens in the absence of cystic fibrosis, who have azoospermia is now possible using surgically retrieved sperm. Transmission of known cystic fibrosis mutations can be avoided by testing the female partner prior to treatment and offering pre-implantation genetic diagnosis if she is a carrier. The effect of infertility and its treatment on genomic imprinting is of increasing concern as our understanding of the mechanisms of imprinting in germ cell development and embryogenesis expands. At present, it is far from clear whether there are longstanding effects of infertility per se or of its treatment on the health of adults who were conceived following assisted reproductive technologies, but available data suggest that this should be of concern and long-term follow-up studies are required. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Genetic Differentiations among the Populations of Salvia japonica (Lamiaceae and Its Related Species

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    SUDARMONO

    2008-03-01

    Full Text Available Morphological and genetic variations within Salvia japonica (Lamiaceae and its related species in Japan were analyzed for clarifying their taxonomic significance. The genetic variations were explored through chloroplast and nuclear ribosomal DNA sequences and allozyme polymorphisms. Since chromosome numbers characterized the genus of Salvia, we also examined whether the karyotypes were different. We examined 58 populations of S. japonica and 14 populations of others species of Salvia. Among the populations of S. japonica represented four forms (f. japonica, f. longipes, f. lanuginosa and f. albiflora. The size of chromosomes were various among Salvia spp. Based on the allozyme as well as the DNA sequence, the populations of S. japonica separated from the others Salvia species. The populations of S. japonica exhibited four combinations of the morphological characters. However, these combinations did not correlate to the four forms of S. japonica. In addition, the morphological variations did not correlate to the allozyme and DNA sequences. It is suggested that the four morphological variations as well as the four form of S. japonica should not considered to be a taxonomic unit; accordingly, S. japonica were considered to be still at the early stage of speciation process.

  3. A Validated Phenotyping Algorithm for Genetic Association Studies in Age-related Macular Degeneration

    Science.gov (United States)

    Simonett, Joseph M.; Sohrab, Mahsa A.; Pacheco, Jennifer; Armstrong, Loren L.; Rzhetskaya, Margarita; Smith, Maureen; Geoffrey Hayes, M.; Fawzi, Amani A.

    2015-01-01

    Age-related macular degeneration (AMD), a multifactorial, neurodegenerative disease, is a leading cause of vision loss. With the rapid advancement of DNA sequencing technologies, many AMD-associated genetic polymorphisms have been identified. Currently, the most time consuming steps of these studies are patient recruitment and phenotyping. In this study, we describe the development of an automated algorithm to identify neovascular (wet) AMD, non-neovascular (dry) AMD and control subjects using electronic medical record (EMR)-based criteria. Positive predictive value (91.7%) and negative predictive value (97.5%) were calculated using expert chart review as the gold standard to assess algorithm performance. We applied the algorithm to an EMR-linked DNA bio-repository to study previously identified AMD-associated single nucleotide polymorphisms (SNPs), using case/control status determined by the algorithm. Risk alleles of three SNPs, rs1061170 (CFH), rs1410996 (CFH), and rs10490924 (ARMS2) were found to be significantly associated with the AMD case/control status as defined by the algorithm. With the rapid growth of EMR-linked DNA biorepositories, patient selection algorithms can greatly increase the efficiency of genetic association study. We have found that stepwise validation of such an algorithm can result in reliable cohort selection and, when coupled within an EMR-linked DNA biorepository, replicates previously published AMD-associated SNPs. PMID:26255974

  4. Cryptic distant relatives are common in both isolated and cosmopolitan genetic samples.

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    Brenna M Henn

    Full Text Available Although a few hundred single nucleotide polymorphisms (SNPs suffice to infer close familial relationships, high density genome-wide SNP data make possible the inference of more distant relationships such as 2(nd to 9(th cousinships. In order to characterize the relationship between genetic similarity and degree of kinship given a timeframe of 100-300 years, we analyzed the sharing of DNA inferred to be identical by descent (IBD in a subset of individuals from the 23andMe customer database (n = 22,757 and from the Human Genome Diversity Panel (HGDP-CEPH, n = 952. With data from 121 populations, we show that the average amount of DNA shared IBD in most ethnolinguistically-defined populations, for example Native American groups, Finns and Ashkenazi Jews, differs from continentally-defined populations by several orders of magnitude. Via extensive pedigree-based simulations, we determined bounds for predicted degrees of relationship given the amount of genomic IBD sharing in both endogamous and 'unrelated' population samples. Using these bounds as a guide, we detected tens of thousands of 2(nd to 9(th degree cousin pairs within a heterogenous set of 5,000 Europeans. The ubiquity of distant relatives, detected via IBD segments, in both ethnolinguistic populations and in large 'unrelated' populations samples has important implications for genetic genealogy, forensics and genotype/phenotype mapping studies.

  5. Fluorescent nanodiamond tracking reveals intraneuronal transport abnormalities induced by brain-disease-related genetic risk factors

    Science.gov (United States)

    Haziza, Simon; Mohan, Nitin; Loe-Mie, Yann; Lepagnol-Bestel, Aude-Marie; Massou, Sophie; Adam, Marie-Pierre; Le, Xuan Loc; Viard, Julia; Plancon, Christine; Daudin, Rachel; Koebel, Pascale; Dorard, Emilie; Rose, Christiane; Hsieh, Feng-Jen; Wu, Chih-Che; Potier, Brigitte; Herault, Yann; Sala, Carlo; Corvin, Aiden; Allinquant, Bernadette; Chang, Huan-Cheng; Treussart, François; Simonneau, Michel

    2017-05-01

    Brain diseases such as autism and Alzheimer's disease (each inflicting >1% of the world population) involve a large network of genes displaying subtle changes in their expression. Abnormalities in intraneuronal transport have been linked to genetic risk factors found in patients, suggesting the relevance of measuring this key biological process. However, current techniques are not sensitive enough to detect minor abnormalities. Here we report a sensitive method to measure the changes in intraneuronal transport induced by brain-disease-related genetic risk factors using fluorescent nanodiamonds (FNDs). We show that the high brightness, photostability and absence of cytotoxicity allow FNDs to be tracked inside the branches of dissociated neurons with a spatial resolution of 12 nm and a temporal resolution of 50 ms. As proof of principle, we applied the FND tracking assay on two transgenic mouse lines that mimic the slight changes in protein concentration (∼30%) found in the brains of patients. In both cases, we show that the FND assay is sufficiently sensitive to detect these changes.

  6. Trichostatin A effects on gene expression in the protozoan parasite Entamoeba histolytica

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    Singh Upinder

    2007-07-01

    Full Text Available Abstract Background Histone modification regulates chromatin structure and influences gene expression associated with diverse biological functions including cellular differentiation, cancer, maintenance of genome architecture, and pathogen virulence. In Entamoeba, a deep-branching eukaryote, short chain fatty acids (SCFA affect histone acetylation and parasite development. Additionally, a number of active histone modifying enzymes have been identified in the parasite genome. However, the overall extent of gene regulation tied to histone acetylation is not known. Results In order to identify the genome-wide effects of histone acetylation in regulating E. histolytica gene expression, we used whole-genome expression profiling of parasites treated with SCFA and Trichostatin A (TSA. Despite significant changes in histone acetylation patterns, exposure of parasites to SCFA resulted in minimal transcriptional changes (11 out of 9,435 genes transcriptionally regulated. In contrast, exposure to TSA, a more specific inhibitor of histone deacetylases, significantly affected transcription of 163 genes (122 genes upregulated and 41 genes downregulated. Genes modulated by TSA were not regulated by treatment with 5-Azacytidine, an inhibitor of DNA-methyltransferase, indicating that in E. histolytica the crosstalk between DNA methylation and histone modification is not substantial. However, the set of genes regulated by TSA overlapped substantially with genes regulated during parasite development: 73/122 genes upregulated by TSA exposure were upregulated in E. histolytica cysts (p-value = 6 × 10-53 and 15/41 genes downregulated by TSA exposure were downregulated in E. histolytica cysts (p-value = 3 × 10-7. Conclusion This work represents the first genome-wide analysis of histone acetylation and its effects on gene expression in E. histolytica. The data indicate that SCFAs, despite their ability to influence histone acetylation, have minimal effects on gene

  7. Field of Genes: An Investigation of Sports-Related Genetic Testing

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    Jennifer K. Wagner

    2012-09-01

    Full Text Available Sports-related genetic testing is a sector of the diverse direct-to-consumer (DTC industry that has not yet been examined thoroughly by academic scholars. A systematic search was used to identify companies in this sector and content analysis of online information was performed. More than a dozen companies were identified. Marketing practices observed generally did not target parents for child testing, and marketing images were mild compared to images used in popular media. Information was provided at a high reading level (industry-wide Flesh-Kincaid Grade Levels > 11. While ~75% of companies provide privacy policies and terms of service prior to purchase and ~40% provide scientific citations for their tests,

  8. The role of molecular genetic factors in age-related macular degeneration.

    Science.gov (United States)

    Almeida, Luciana Negrão Frota de; Carolino, Rachel Melilo; Sperandio, Diogo Cazelli; Nehemy, Márcio Bittar; De Marco, L A

    2009-01-01

    Age-related macular degeneration (AMD) is the most frequent cause of irreversible blindness in the elderly in developed countries. Although the etiology of AMD remains largely unknown, numerous studies have suggested that both genes and environmental risk factors significantly influence the risk of developing AMD. Recently, single nucleotide polymorphisms, DNA sequence variations found within the complement factor H (CFH) gene, have been found to be strongly associated with the development of AMD. Several other genes have had at least one positive association finding and deserve further exploration. The purpose of this review is to provide an extensive report of the current data of AMD genetics and the contribution of this knowledge helps to the better understanding of its pathophysiology.

  9. Age-related macular degeneration: genetic and environmental factors of disease.

    Science.gov (United States)

    Chen, Yuhong; Bedell, Matthew; Zhang, Kang

    2010-10-01

    Age-related macular degeneration (AMD) is the most common cause of visual impairment among the elderly in developed countries, and its prevalence is thus increasing as the population ages; however, treatment options remain limited because the etiology and pathogenesis of AMD are incompletely defined. Recently, much progress has been made in gene discovery and mechanistic studies, which clearly indicate that AMD involves the interaction of multiple genetic and environmental factors. The identification of genes that have a substantial impact on the risk for AMD is not only facilitating the diagnosis and screening of populations at risk but is also elucidating key molecular pathways of pathogenesis. Pharmacogenetic studies of treatment responsiveness among patients with the "wet" form of AMD are increasingly proving to be clinically relevant; pharmacogenetic approaches hold great promise for both identifying patients with the best chance for vision recovery as well as tailoring individualized therapies.

  10. An integrative systems genetics approach reveals potential causal genes and pathways related to obesity

    DEFF Research Database (Denmark)

    Kogelman, Lisette; Zhernakova, Daria V.; Westra, Harm-Jan;

    2015-01-01

    expression analysis was performed using the Obesity Index as a continuous variable in a linear model. eQTL mapping was then performed to integrate 60 K porcine SNP chip data with the RNA sequencing data. Results were restricted based on genome-wide significant single nucleotide polymorphisms, detected...... polymorphisms to detect obesity-related genes and pathways. Building a co-expression network using eQTLs resulted in the detection of a module strongly associated with lipid pathways. Furthermore, we detected several obesity candidate genes, for example, ENPP1, CTSL, and ABHD12B. CONCLUSIONS: To our knowledge......BACKGROUND: Obesity is a multi-factorial health problem in which genetic factors play an important role. Limited results have been obtained in single-gene studies using either genomic or transcriptomic data. RNA sequencing technology has shown its potential in gaining accurate knowledge about...

  11. Genetic counseling for individuals with hemoglobin disorders and for their relatives: a systematic literature review

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    Tatiana Dela-Sávia Ferreira

    2014-10-01

    Full Text Available Objective: To identify genetic counseling programs that do not encourage therapeutic abortion for individuals with hemoglobin disorders and/or for their relatives. Method: Systematic literature review of articles published from 2001 to 2012 that are located in the PubMed, LILACS, SciELO and SCOPUS databases using keywords in Portuguese, English and Spanish and that met the inclusion and exclusion criteria described on a standardized form. Results: A total of 409 articles were located, but only eight (1.9% were selected for analysis. Conclusion: Although seldom mentioned in the literature, educational/preventive programs targeting hemoglobinopathies are feasible and allow the affected individuals to acquire knowledge on the consequences of this condition and their odds of transmitting it.

  12. Deep phenotyping unveils hidden traits and genetic relations in subtle mutants

    Science.gov (United States)

    San-Miguel, Adriana; Kurshan, Peri T.; Crane, Matthew M.; Zhao, Yuehui; McGrath, Patrick T.; Shen, Kang; Lu, Hang

    2016-11-01

    Discovering mechanistic insights from phenotypic information is critical for the understanding of biological processes. For model organisms, unlike in cell culture, this is currently bottlenecked by the non-quantitative nature and perceptive biases of human observations, and the limited number of reporters that can be simultaneously incorporated in live animals. An additional challenge is that isogenic populations exhibit significant phenotypic heterogeneity. These difficulties limit genetic approaches to many biological questions. To overcome these bottlenecks, we developed tools to extract complex phenotypic traits from images of fluorescently labelled subcellular landmarks, using C. elegans synapses as a test case. By population-wide comparisons, we identified subtle but relevant differences inaccessible to subjective conceptualization. Furthermore, the models generated testable hypotheses of how individual alleles relate to known mechanisms or belong to new pathways. We show that our model not only recapitulates current knowledge in synaptic patterning but also identifies novel alleles overlooked by traditional methods.

  13. Genetic Comparison of B. Anthracis and its Close Relatives Using AFLP and PCR Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, P.J.; Hill, K.K.; Laker, M.T.; Ticknor, L.O.; Keim, P.S.

    1999-02-01

    Amplified Fragment length Polymorphism (AFLP) analysis allows a rapid, relatively simple analysis of a large portion of a microbial genome, providing information about the species and its phylogenetic relationship to other microbes (Vos, et al., 1995). The method simply surveys the genome for length and sequence polymorphisms. The pattern identified can be used for comparison to the genomes of other species. Unlike other methods, it does not rely on analysis of a single genetic locus that may bias the interpretation of results and it does not require any prior knowledge of the targeted organism. Moreover, a standard set of reagents can be applied to any species without using species-specific information or molecular probes. The authors are using AFLP's to rapidly identify different bacterial species. A comparison of AFLP profiles generated from a large battery of B. anthracis strains shows very little variability among different isolates (Keim, et al., 1997). By contrast, there is a significant difference between AFLP profiles generated for any B. anthracis strain and even the most closely related Bacillus species. Sufficient variability is apparent among all known microbial species to allow phylogenetic analysis based on large numbers of genetically unlinked loci. These striking differences among AFLP profiles allow unambiguous identification of previously identified species and phylogenetic placement of newly characterized isolates relative to known species based on a large number of independent genetic loci. Data generated thus far show that the method provides phylogenetic analyses that are consistent with other widely accepted phylogenetic methods. However, AFLP analysis provides a more detailed analysis of the targets and samples a much larger portion of the genome. Consequently, it provides an inexpensive, rapid means of characterizing microbial isolates to further differentiate among strains and closely related microbial species. Such information

  14. Mathematics is differentially related to reading comprehension and word decoding: Evidence from a genetically-sensitive design

    Science.gov (United States)

    Harlaar, Nicole; Kovas, Yulia; Dale, Philip S.; Petrill, Stephen A.; Plomin, Robert

    2013-01-01

    Although evidence suggests that individual differences in reading and mathematics skills are correlated, this relationship has typically only been studied in relation to word decoding or global measures of reading. It is unclear whether mathematics is differentially related to word decoding and reading comprehension. The current study examined these relationships at both a phenotypic and etiological level in a population-based cohort of 5162 twin pairs at age 12. Multivariate genetic analyses of latent phenotypic factors of mathematics, word decoding and reading comprehension revealed substantial genetic and shared environmental correlations among all three domains. However, the phenotypic and genetic correlations between mathematics and reading comprehension were significantly greater than between mathematics and word decoding. Independent of mathematics, there was also evidence for genetic and nonshared environmental links between word decoding and reading comprehension. These findings indicate that word decoding and reading comprehension have partly distinct relationships with mathematics in the middle school years. PMID:24319294

  15. Antibodies against Entamoeba histolytica in individuals with intestinal amoebiasis presenting cysts and/or trophozoites in the feces Anticorpos anti-Entamoeba histolylica em indivíduos com amebíase intestinal apresentando cistos e/ou trofozoitas nas fezes

    Directory of Open Access Journals (Sweden)

    Maria das Graças Carvalho

    1991-10-01

    Full Text Available Serum samples were obtained from 154 individuals infected with Entamoeba histolytica (78 symptomatic and 76 asymptomatic. Twelve had trophozoites in the feces whereas 142 had only cysts. The sera were used to test the existence of antibodies anti-Entamoeba histolytica employing the Indirect Hemagglutination (IHA, Indirect Immunofluoresccnce (IFAT, Complement Fixation Reaction (CFR and Counterimmunoelectrophoresis (CIEP. For those individuals with trophozoites in their feces, 75.0 were positive by IHA and IFAT, 83.0 by CFR and 41.7 by CIEP. In individuals who had only cysts, positive results by the same tests were respectively, 5.6%, 12.0%, 19.0% and 5.6%. The difference in relation to the tilers of antibodies detected through IHA, IFAT, CFR and CIEP and in relation to the presence of trophozoites or cysts in the feces was significative for four immunological reactions when X², was employed (P Amostras de soros foram obtidas de 154 indivíduos comprovadamente parasitados pela Entamoeba histolytica (78 sintomáticos c 76 assintomáticos. Doze apresentavam trofozoitas nas fezes, enquanto 142 tinham apenas cistos. Os soros foram utilizados para testar a ocorrência de anticorpos anti-Entamoeba histolytica, empregando-se para tal, Reação de Hemaglutinação Indireta (HAI, Reação de Imunofluorescência Indireta (RIFI, Reação de Fixação de Complemento (RFC e Contraimunoeletroforese (CIEP. Entre os soros dos indivíduos com trofozoitas em suas fezes, 75,0% foram positivos para HAI e RIFI, 83,3% por RFC, e 41,7% por CIEP. Nos indivíduos que tinham apenas cistos, resultados positivos pelos mesmos testes foram respectivamente, 5,6%; 12,0%; 19,0% c 5,6%. A diferença cm relação aos títulos de anticorpos detectados através de HAI, RIFI, RFC e CIEP e em relação à presença de trofozoitas ou cistos nas fezes foi significativa para as quatro reações imunológicas, quando X² foi empregado (P < 0,05.

  16. Acceptance of genetically modified foods: the relation between technology and evaluation.

    Science.gov (United States)

    Tenbült, Petra; De Vries, Nanne K; van Breukelen, Gerard; Dreezens, Ellen; Martijn, Carolien

    2008-07-01

    This study investigates why consumers accept different genetically modified food products to different extents. The study shows that whether food products are genetically modified or not and whether they are processed or not are the two important features that affect the acceptance of food products and their evaluation (in terms of perceived healthiness, naturalness, necessity and tastiness). The extent to which these evaluation attributes and acceptance of a product are affected by genetic modification or processing depends on whether the product is negatively affected by the other technology: Any technological change to a 'natural' product (when nonprocessed products are genetically modified or when non-genetically modified products are processed) affect evaluation and acceptance stronger than a change to an technologically adapted product (when processed products are also genetically modified or vice versa). Furthermore, evaluation attributes appear to mediate the effects of genetic modification and processing on acceptance.

  17. Relative role of life-history traits and historical factors in shaping genetic population structure of sardines (Sardina pilchardus

    Directory of Open Access Journals (Sweden)

    Zardoya Rafael

    2007-10-01

    Full Text Available Abstract Background Marine pelagic fishes exhibit rather complex patterns of genetic differentiation, which are the result of both historical processes and present day gene flow. Comparative multi-locus analyses based on both nuclear and mitochondrial genetic markers are probably the most efficient and informative approach to discerning the relative role of historical events and life-history traits in shaping genetic heterogeneity. The European sardine (Sardina pilchardus is a small pelagic fish with a relatively high migratory capability that is expected to show low levels of genetic differentiation among populations. Previous genetic studies based on meristic and mitochondrial control region haplotype frequency data supported the existence of two sardine subspecies (S. p. pilchardus and S. p. sardina. Results We investigated genetic structure of sardine among nine locations in the Atlantic Ocean and Mediterranean Sea using allelic size variation of eight specific microsatellite loci. Bayesian clustering and assignment tests, maximum likelihood estimates of migration rates, as well as classical genetic-variance-based methods (hierarchical AMOVA test and RST pairwise comparisons supported a single evolutionary unit for sardines. These analyses only detected weak but significant genetic differentiation, which followed an isolation-by-distance pattern according to Mantel test. Conclusion We suggest that the discordant genetic structuring patterns inferred based on mitochondrial and microsatellite data might indicate that the two different classes of molecular markers may be reflecting different and complementary aspects of the evolutionary history of sardine. Mitochondrial data might be reflecting past isolation of sardine populations into two distinct groupings during Pleistocene whereas microsatellite data reveal the existence of present day gene flow among populations, and a pattern of isolation by distance.

  18. Genetic uptake in BRCA-mutation families is related to emotional and behavioral communication characteristics of index patients.

    NARCIS (Netherlands)

    Landsbergen, K.M.; Verhaak, C.M.; Kraaimaat, F.W.; Hoogerbrugge-van der Linden, N.

    2005-01-01

    INTRODUCTION: Carriers of a hereditary mutation in BRCA are at high risk for breast and ovarian cancer. The first person from a family known to carry the mutation, the index person, has to share genetic information with relatives. This study is aimed at determining the number of relatives tested for

  19. Genetic engineering in agriculture and corporate engineering in public debate: risk, public relations, and public debate over genetically modified crops.

    Science.gov (United States)

    Patel, Rajeev; Torres, Robert J; Rosset, Peter

    2005-01-01

    Corporations have long influenced environmental and occupational health in agriculture, doing a great deal of damage, making substantial profits, and shaping public debate to make it appear that environmental misfortunes are accidents of an otherwise well-functioning system, rather than systemic. The debate over the genetically modified (GM) crops is an example. The largest producer of commercial GM seeds, Monsanto, exemplifies the industry's strategies: the invocation of poor people as beneficiaries, characterization of opposition as technophobic or anti-progress, and portrayal of their products as environmentally beneficial in the absence of or despite the evidence. This strategy is endemic to contemporary market capitalism, with its incentives to companies to externalize health and environmental costs to increase profits.

  20. Genetic variation in meat production related traits in reindeer (Rangifer t. tarandus

    Directory of Open Access Journals (Sweden)

    Kirsi Muuttoranta

    2014-02-01

    Full Text Available Normal 0 21 false false false SV X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Normal tabell"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;} In reindeer husbandry, animal breeding could offer tools for improving productivity by selection. The traits affecting meat production efficiency are primarily related to calf growth and survival, and to dam’s longevity and lifetime ability to raise heavy calves. Information on genetic (covariation in these traits is scarce but needed in estimating the potential and effectiveness of selection as well as biological constraints. The objectives of the study were to estimate these genetic parameters from the data of an experimental reindeer herd at Kutuharju (Inari, Finland. Heritabilities (h2 and genetic correlations (rg among the average daily gain of calves (ADG, dams’ age at maturity, individual fitness (λind and the cumulative sum of her calves’ weaning weight over seven years (WW7 were studied with AS-Reml software using the dataset from the experimental herd. The pedigree included also sire information to allow the separation of the maternal effects. Direct and maternal heritabilities of ADG were moderate (0.24±0.09 and 0.18±0.05, respectively and the direct-maternal correlation was highly negative (-0.73±0.17. Indeed, selection on growth necessitates information on both calf and dam. The genetic correlation of growth with birth date and birth weight could not be detected with the data. The age

  1. Genetic mapping and comparative analysis of seven mutants related to seed fiber development in cotton.

    Science.gov (United States)

    Rong, Junkang; Pierce, Gary J; Waghmare, Vijay N; Rogers, Carl J; Desai, Aparna; Chee, Peng W; May, O Lloyd; Gannaway, John R; Wendel, Jonathan F; Wilkins, Thea A; Paterson, Andrew H

    2005-10-01

    Mapping of genes that play major roles in cotton fiber development is an important step toward their cloning and manipulation, and provides a test of their relationships (if any) to agriculturally-important QTLs. Seven previously identified fiber mutants, four dominant (Li (1), Li (2), N (1) and Fbl) and three recessive (n (2), sma-4(h (a)), and sma-4(fz)), were genetically mapped in six F(2) populations comprising 124 or more plants each. For those mutants previously assigned to chromosomes by using aneuploids or by linkage to other morphological markers, all map locations were concordant except n (2), which mapped to the homoeolog of the chromosome previously reported. Three mutations with primary effects on fuzz fibers (N (1), Fbl, n (2)) mapped near the likelihood peaks for QTLs that affected lint fiber productivity in the same populations, perhaps suggesting pleiotropic effects on both fiber types. However, only Li (1) mapped within the likelihood interval for 191 previously detected lint fiber QTLs discovered in non-mutant crosses, suggesting that these mutations may occur in genes that played early roles in cotton fiber evolution, and for which new allelic variants are quickly eliminated from improved germplasm. A close positional association between sma-4(h ( a )), two leaf and stem-borne trichome mutants (t (1) , t (2)), and a gene previously implicated in fiber development, sucrose synthase, raises questions about the possibility that these genes may be functionally related. Increasing knowledge of the correspondence of the cotton and Arabidopsis genomes provides several avenues by which genetic dissection of cotton fiber development may be accelerated.

  2. On the relation between moral, legal and evaluative justifications of pre-implantation genetic diagnosis (PGD).

    Science.gov (United States)

    Lohmann, Georg

    2003-01-01

    In Germany the question whether to uphold or repeal the judicial prohibition on Pre-implantation Genetic Diagnosis (PGD) is being debated from quite different standpoints. This paper differentiates the major arguments according to their reasons as a) moral, b) evaluative (i.e. cultural/religious), and c) legal. The arguments for and against PGD can be divided by content into three groups: arguments relating to the status of the embryo, focusing on individual actions in the implementation of PGD, and relating to the foreseeable or probable consequences of PGD. In Germany, from a legal perspective, the status of the embryo does not permit the intervention of PGD; from a purely moral perspective, a prohibition on PGD does not appear defensible. It remains an open question, however, whether the moral argument permitting PGD should be restricted for evaluative (cultural) reasons. The paper discusses the species-ethical reasons, for which Jurgen Habermas sees worrisome consequences in the wake of PGD to the extent that we comprehend it as the forerunner of a 'positive eugenics'. It would so disrupt the natural preconditions of our universal morality. The question of whether to prohibit or allow PGD is not merely a question of simple moral and/or legal arguments, but demands a choice between evaluative, moral and (still to be specified) species-ethical arguments, and the question remains open.

  3. The molecular genetic basis of age-related macular degeneration: an overview

    Indian Academy of Sciences (India)

    Saritha Katta; Inderjeet Kaur; Subhabrata Chakrabarti

    2009-12-01

    Age-related macular degeneration (AMD) is a complex disorder of the eye and the third leading cause of blindness worldwide. With a multifactorial etiology, AMD results in progressive loss of central vision affecting the macular region of the eye in elderly. While the prevalence is relatively higher in the Caucasian populations, it has gradually become a major public health issue among the non-Caucasian populations (including Indians) as well due to senescence, rapidly changing demographics and life-style factors. Recent genome-wide association studies (GWAS) on large case–control cohorts have helped in mapping genes in the complement cascade that are involved in the regulation of innate immunity with AMD susceptibility. Genes involved with mitochondrial oxidative stress and extracellular matrix regulation also play a role in AMD pathogenesis. Majority of the associations observed in complement (CFH, CFB, C2 and C3) and other (ARMS2 and HTRA1) genes have been replicated in diverse populations worldwide. Gene–gene (CFH with ARMS2 and HTRA1) interactions and correlations with environmental traits (smoking and body mass index) have been established as significant covariates in AMD pathology. In this review, we have provided an overview on the underlying molecular genetic mechanisms in AMD worldwide and highlight the AMD-associated-candidate genes and their potential role in disease pathogenesis.

  4. Rapid Diagnosis of Intestinal Parasitic Protozoa, with a Focus on Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Anjana Singh

    2009-01-01

    Full Text Available Entamoeba histolytica is an invasive intestinal pathogenic parasitic protozoan that causes amebiasis. It must be distinguished from Entamoeba dispar and E. moshkovskii, nonpathogenic commensal parasites of the human gut lumen that are morphologically identical to E. histolytica. Detection of specific E. histolytica antigens in stools is a fast, sensitive technique that should be considered as the method of choice. Stool real-time PCR is a highly sensitive and specific technique but its high cost make it unsuitable for use in endemic areas where there are economic constraints. Serology is an important component of the diagnosis of intestinal and especially extraintestinal amebiasis as it is a sensitive test that complements the detection of the parasite antigens or DNA. Circulating Gal/GalNac lectin antigens can be detected in the serum of patients with untreated amoebic liver abscess. On the horizon are multiplex real-time PCR assays which permit the identification of multiple enteropathogens with high sensitivity and specificity.

  5. Structure of uridine diphosphate N-acetylglucosamine pyrophosphorylase from Entamoeba histolytica.

    Science.gov (United States)

    Edwards, Thomas E; Gardberg, Anna S; Phan, Isabelle Q H; Zhang, Yang; Staker, Bart L; Myler, Peter J; Lorimer, Donald D

    2015-05-01

    Uridine diphosphate N-acetylglucosamine pyrophosphorylase (UAP) catalyzes the final step in the synthesis of UDP-GlcNAc, which is involved in cell-wall biogenesis in plants and fungi and in protein glycosylation. Small-molecule inhibitors have been developed against UAP from Trypanosoma brucei that target an allosteric pocket to provide selectivity over the human enzyme. A 1.8 Å resolution crystal structure was determined of UAP from Entamoeba histolytica, an anaerobic parasitic protozoan that causes amoebic dysentery. Although E. histolytica UAP exhibits the same three-domain global architecture as other UAPs, it appears to lack three α-helices at the N-terminus and contains two amino acids in the allosteric pocket that make it appear more like the enzyme from the human host than that from the other parasite T. brucei. Thus, allosteric inhibitors of T. brucei UAP are unlikely to target Entamoeba UAPs.

  6. Discovery of Entamoeba histolytica hexokinase 1 inhibitors through homology modeling and virtual screening.

    Science.gov (United States)

    Saucedo-Mendiola, María Leticia; Salas-Pacheco, José Manuel; Nájera, Hugo; Rojo-Domínguez, Arturo; Yépez-Mulia, Lilián; Avitia-Domínguez, Claudia; Téllez-Valencia, Alfredo

    2014-06-01

    Entamoeba histolytica, the parasite which causes amebiasis is responsible for 110,000 deaths a year. Entamoeba histolytica depends on glycolysis to obtain ATP for cellular work. According to metabolic flux studies, hexokinase exerts the highest flux control of this metabolic pathway; therefore, it is an excellent target in the search of new antiamebic drugs. To this end, a tridimensional model of E. histolytica hexokinase 1 (EhHK1) was constructed and validated by homology modeling. After virtual screening of 14,400 small molecules, the 100 with the best docking scores were selected, purchased and assessed in their inhibitory capacity. The results showed that three molecules (compounds 2921, 11275 and 2755) inhibited EhHK1 with an I50 of 48, 91 and 96 µM, respectively. Thus, we found the first inhibitors of EhHK1 that can be used in the search of new chemotherapeutic agents against amebiasis.

  7. Prevalence of antibodies against Entamoeba histolytica in Mexico measured by ELISA.

    Science.gov (United States)

    González, C R; Isibasi, A; Ortiz-Navarrete, V; Paniagua, J; García, J A; Ramirez, A; Salvatierra, B; Tapia, R; Sepúlveda, J; Gutiérrez, G

    1995-12-01

    The prevalence of antibodies against Entamoeba histolytica was studied in the Mexican population using an immunoenzyme assay in solid phase (ELISA) and semiautomatic equipment. The antigen was a mixture of membrane proteins obtained by Triton X-100 extraction from an axenic culture of Entamoeba histolytica HM1-IMSS. The method was standardized by comparing serum samples from amoebic liver abscess patients with healthy volunteers. From the 60,538 samples supplied by the National Seroepidemiology Survey, antibodies were found in 4.49% (4.32-4.65% at 95% confidence limit). More significant titres occurred in the central region of the country. The ratio female to male was 1.25:1. The population living in metropolitan areas had probably been infected at a younger age than those living in the country. Important differences were found in the seroprevalence obtained by ELISA compared with a study which used indirect haemagglutination (IHA) in the same sample frame.

  8. Novel hemagglutinating, hemolytic and cytotoxic activities of the intermediate subunit of Entamoeba histolytica lectin

    Science.gov (United States)

    Kato, Kentaro; Yahata, Kazuhide; Gopal Dhoubhadel, Bhim; Fujii, Yoshito; Tachibana, Hiroshi

    2015-01-01

    Galactose and N-acetyl-D-galactosamine (Gal/GalNAc) inhibitable lectin of Entamoeba histolytica, a common protozoan parasite, has roles in pathogenicity and induction of protective immunity in mouse models of amoebiasis. The lectin consists of heavy (Hgl), light (Lgl), and intermediate (Igl) subunits. Hgl has lectin activity and Lgl does not, but little is known about the activity of Igl. In this study, we assessed various regions of Igl for hemagglutinating activity using recombinant proteins expressed in Escherichia coli. We identified a weak hemagglutinating activity of the protein. Furthermore, we found novel hemolytic and cytotoxic activities of the lectin, which resided in the carboxy-terminal region of the protein. Antibodies against Igl inhibited the hemolytic activity of Entamoeba histolytica trophozoites. This is the first report showing hemagglutinating, hemolytic and cytotoxic activities of an amoebic molecule, Igl. PMID:26354528

  9. Establishment of a transient transfection system and expression of firefly luciferase in Entamoeba invadens.

    Science.gov (United States)

    Singh, Nishant; Ojha, Sandeep; Bhattacharya, Alok; Bhattacharya, Sudha

    2012-05-01

    Entamoeba invadens is used as a model system to study trophozoite to cyst differentiation since Entamoeba histolytica, the causative agent of amoebiasis cannot encyst in culture. However, a system for introduction of cloned genes in E. invadens is not available. Here we report an electroporation-based method for transfection of E. invadens tophozoites and demonstrate the expression of firefly luciferase reporter gene driven from the E. invadens ribosomal protein L3 promoter. The efficiency of luciferase expression driven from the promoters of three different E. invadens genes (rpl3, rps10 and h2b) was tested and found to correlate with the in vivo expression levels of the respective gene. This system will permit the analysis of regulatory elements required for gene expression in E. invadens.

  10. Prevalence of antibodies against Entamoeba histolytica in Mexico measured by ELISA

    Science.gov (United States)

    González, C. R.; Isibasi, A.; Ortiz-Navarrete, V.; Paniagua, J.; García, J. A.; Ramirez, A.; Salvatierra, B.; Tapia, R.; Sepúlveda, J.; Gutiérrez, G.; Kumate, J.

    1995-01-01

    The prevalence of antibodies against Entamoeba histolytica was studied in the Mexican population using an immunoenzyme assay in solid phase (ELISA) and semiautomatic equipment. The antigen was a mixture of membrane proteins obtained by Triton X-100 extraction from an axenic culture of Entamoeba histolytica HM1-IMSS. The method was standardized by comparing serum samples from amoebic liver abscess patients with healthy volunteers. From the 60538 samples supplied by the National Seroepidemiology Survey, antibodies were found in 4·49% (4·32—4·65% at 95% confidence limit). More significant titres occurred in the central region of the country. The ratio female to male was 1·25:1. The population living in metropolitan areas had probably been infected at a younger age than those living in the country. Important differences were found in the seroprevalence obtained by ELISA compared with a study which used indirect haemagglutination (IHA) in the same sample frame. PMID:8557086

  11. Relative influences of historical and contemporary forces shaping the distribution of genetic variation in the Atlantic killifish, Fundulus heteroclitus.

    Science.gov (United States)

    Duvernell, David D; Lindmeier, James B; Faust, Katherine E; Whitehead, Andrew

    2008-03-01

    A major goal of population genetics research is to identify the relative influences of historical and contemporary processes that serve to structure genetic variation. Most population genetic models assume that populations exist in a state of migration-drift equilibrium. However, in the past this assumption has rarely been verified, and is likely rarely achieved in natural populations. We assessed the equilibrium status at both local and regional scales of the Atlantic killifish, Fundulus heteroclitus. This species is a model organism for the study of adaptive clinal variation, but has also experienced a complicated history of range expansion and secondary contact following allopatric divergence, potentially obscuring the influence of contemporary evolutionary processes. Presumptively neutral genetic markers (microsatellites) demonstrated zones of secondary intergradation among coastal populations centred around northern New Jersey and the Chesapeake Bay region. Analysis of genetic variation indicated isolation by distance among some populations and provided supporting evidence that the Delaware Bay, but not the Chesapeake Bay, has acted as a barrier to dispersal among coastal populations. Bayesian estimates indicated large effective population sizes and low migration rates, and were in good agreement with empirically derived estimates of population and neighbourhood size from mark-recapture studies. These data indicate that populations are not in migration-drift equilibrium at a regional scale, and suggest that contributing factors include large population size combined with relatively low migration rates. These conditions should be considered when interpreting the evolutionary significance of the distribution of genetic variation among F. heteroclitus populations.

  12. Migration and population genetics of the grain aphid Macrosiphum miscanti (Takahashi) in relation to the geographic distance and gene flow

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; SHEN Zuorui; LI Zhihong; GAO Lingwang

    2005-01-01

    The population genetics of the grain aphid Macrosiphum miscanti (Takahashi) is analyzed by microsatellite markers.Samples collected from 15 locations in China have been examined at 5 polymorphic microsatellite loci. Overall, genetic diversity displays a relation between the migration and gene flow in the grain aphid: a free and frequent gene flow is found in the eastern populations, and gene isolation occurs in the two western populations, especially Datong population and Guiyang population. The natural barriers may present an insurmountable obstacle preventing gene flow and aphid migration. However, a spatial genetic differentiation between populations is correlated with their geographical separation, indicating the geographic differentiation may play an important role in shaping the genetic structure of M. miscanti populations. In addition, most populations of grain aphids are out of Hardy-Weinberg equilibrium and there is heterozygote deficit. Based on F statistics, the average genetic differentiation among different geographical populations is relatively low. It seems that the long distance migration of the grain aphid may enhance gene flow and decrease genetic differentiation among different populations.

  13. Responsiveness of cardiometabolic-related microbiota to diet is influenced by host genetics

    OpenAIRE

    O’Connor, Annalouise; Quizon, Pamela M.; Albright, Jody E.; Lin, Fred T.; Brian J Bennett

    2014-01-01

    Intestinal microbial community structure is driven by host genetics in addition to environmental factors such as diet. In comparison with environmental influences, the effect of host genetics on intestinal microbiota, and how host-driven differences alter host metabolism is unclear. Additionally, the interaction between host genetics and diet, and the impact on the intestinal microbiome and possible down-stream effect on host metabolism is not fully understood, but represents another aspects ...

  14. [Genetic Connectivity Between Sympatric Populations of Closely Related Char Species, Dolly Varden Salvelinus malma and White Char Salvelinus albus].

    Science.gov (United States)

    Salmenkova, E A

    2016-01-01

    The closely related chars Salvelinus malma and Salvelinus albus, which sympatrically inhabit the Kamchatka River basin and Kronotsky Lake (Kamchatka), attract the attention of the researchers because of their debated origin and taxonomic status. Previous studies of sympatric populations of these chars revealed small but statistically significant genetic differences between these species at a number of molecular markers, suggesting the presence of the genetic exchange and hybridization. In this study, based on genotypic characterization of nine microsatellite loci, a considerable level of historical and contemporary genetic migration between sympatric populations of these chars was demonstrated. At the individual level a high degree of hybridization was observed, mainly among the Dolly Varden individuals from the studied populations. The obtained evidence on the genetic connectivity between sympatric S. malma and S. albus do not support the separate species status of S. albus.

  15. Identification and characterization of microRNAs from Entamoeba histolytica HM1-IMSS.

    Science.gov (United States)

    Mar-Aguilar, Fermín; Trevino, Victor; Salinas-Hernández, Jannet E; Taméz-Guerrero, Marcela M; Barrón-González, María P; Morales-Rubio, Eufemia; Treviño-Neávez, Jaime; Verduzco-Martínez, Jorge A; Morales-Vallarta, Mario R; Reséndez-Pérez, Diana

    2013-01-01

    Entamoeba histolytica is the causative agent of amebiasis, a disease that is a major source of morbidity and mortality in the developing world. MicroRNAs (miRNAs) are a large group of non-coding RNAs that play important roles in regulating gene expression and protein translation in animals. Genome-wide identification of miRNAs is a critical step to facilitating our understanding of genome organization, genome biology, evolution, and post-transcriptional regulation. We sequenced a small RNA library prepared from a culture of trophozoites of Entamoeba histolytica Strain HM1-IMSS using a deep DNA sequencing approach. Deep sequencing yielded 16 million high-quality short sequence reads containing a total of 5 million non-redundant sequence reads. Based on a bioinformatics pipeline, we found that only 0.5% of these non-redundant small RNA reads were a perfect match with the drafted E. histolytica genome. We did not find miRNA homologs in plant or animal miRNAs. We discovered 199 new potential Entamoeba histolytica miRNAs. The expression and sequence of these Ehi-miRNAs were further validated through microarray by µParaflo Microfluidic Biochip Technology. Ten potential miRNAs were additionally confirmed by real time RT-PCR analysis. Prediction of target genes matched 32 known genes and 34 hypothetical genes. These results show that there is a number of regulatory miRNAs in Entamoeba histolytica. The collection of miRNAs in this parasite could be used as a new platform to study genomic structure, gene regulation and networks, development, and host-parasite interactions.

  16. Identification and Characterization of microRNAS from Entamoeba histolytica HM1-IMSS

    Science.gov (United States)

    Salinas-Hernández, Jannet E.; Taméz-Guerrero, Marcela M.; Barrón-González, María P.; Morales-Rubio, Eufemia; Treviño-Neávez, Jaime; Verduzco-Martínez, Jorge A.; Morales-Vallarta, Mario R.; Reséndez-Pérez, Diana

    2013-01-01

    Background Entamoeba histolytica is the causative agent of amebiasis, a disease that is a major source of morbidity and mortality in the developing world. MicroRNAs (miRNAs) are a large group of non-coding RNAs that play important roles in regulating gene expression and protein translation in animals. Genome-wide identification of miRNAs is a critical step to facilitating our understanding of genome organization, genome biology, evolution, and post-transcriptional regulation. Methodology/Principal Findings We sequenced a small RNA library prepared from a culture of trophozoites of Entamoeba histolytica Strain HM1-IMSS using a deep DNA sequencing approach. Deep sequencing yielded 16 million high-quality short sequence reads containing a total of 5 million non-redundant sequence reads. Based on a bioinformatics pipeline, we found that only 0.5% of these non-redundant small RNA reads were a perfect match with the drafted E. histolytica genome. We did not find miRNA homologs in plant or animal miRNAs. We discovered 199 new potential Entamoeba histolytica miRNAs. The expression and sequence of these Ehi-miRNAs were further validated through microarray by µParaflo Microfluidic Biochip Technology. Ten potential miRNAs were additionally confirmed by real time RT-PCR analysis. Prediction of target genes matched 32 known genes and 34 hypothetical genes. Conclusions/Significance These results show that there is a number of regulatory miRNAs in Entamoeba histolytica. The collection of miRNAs in this parasite could be used as a new platform to study genomic structure, gene regulation and networks, development, and host-parasite interactions. PMID:23874540

  17. Biochemical characterization of rat colonic mucins secreted in response to Entamoeba histolytica.

    OpenAIRE

    Tse, S K; Chadee, K

    1992-01-01

    Invasion of the colonic mucosa by Entamoeba histolytica trophozoites is preceded by colonic mucus depletion. The aim of our studies was to determine whether E. histolytica caused a differential secretion of mucin species in a rat colonic loop model. Mucus secretion in response to amoebae was followed by release of acid-precipitable 3H-glucosamine metabolically labelled glycoproteins and in vitro labelling of glycoprotein secretion with NaB3H4. The secretory response consisted of high-Mr goble...

  18. Identification and characterization of microRNAs from Entamoeba histolytica HM1-IMSS.

    Directory of Open Access Journals (Sweden)

    Fermín Mar-Aguilar

    Full Text Available BACKGROUND: Entamoeba histolytica is the causative agent of amebiasis, a disease that is a major source of morbidity and mortality in the developing world. MicroRNAs (miRNAs are a large group of non-coding RNAs that play important roles in regulating gene expression and protein translation in animals. Genome-wide identification of miRNAs is a critical step to facilitating our understanding of genome organization, genome biology, evolution, and post-transcriptional regulation. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced a small RNA library prepared from a culture of trophozoites of Entamoeba histolytica Strain HM1-IMSS using a deep DNA sequencing approach. Deep sequencing yielded 16 million high-quality short sequence reads containing a total of 5 million non-redundant sequence reads. Based on a bioinformatics pipeline, we found that only 0.5% of these non-redundant small RNA reads were a perfect match with the drafted E. histolytica genome. We did not find miRNA homologs in plant or animal miRNAs. We discovered 199 new potential Entamoeba histolytica miRNAs. The expression and sequence of these Ehi-miRNAs were further validated through microarray by µParaflo Microfluidic Biochip Technology. Ten potential miRNAs were additionally confirmed by real time RT-PCR analysis. Prediction of target genes matched 32 known genes and 34 hypothetical genes. CONCLUSIONS/SIGNIFICANCE: These results show that there is a number of regulatory miRNAs in Entamoeba histolytica. The collection of miRNAs in this parasite could be used as a new platform to study genomic structure, gene regulation and networks, development, and host-parasite interactions.

  19. Phylogenomic study indicates widespread lateral gene transfer in Entamoeba and suggests a past intimate relationship with parabasalids.

    Science.gov (United States)

    Grant, Jessica R; Katz, Laura A

    2014-09-01

    Lateral gene transfer (LGT) has impacted the evolutionary history of eukaryotes, though to a lesser extent than in bacteria and archaea. Detecting LGT and distinguishing it from single gene tree artifacts is difficult, particularly when considering very ancient events (i.e., over hundreds of millions of years). Here, we use two independent lines of evidence--a taxon-rich phylogenetic approach and an assessment of the patterns of gene presence/absence--to evaluate the extent of LGT in the parasitic amoebozoan genus Entamoeba. Previous work has suggested that a number of genes in the genome of Entamoeba spp. were acquired by LGT. Our approach, using an automated phylogenomic pipeline to build taxon-rich gene trees, suggests that LGT is more extensive than previously thought. Our analyses reveal that genes have frequently entered the Entamoeba genome via nonvertical events, including at least 116 genes acquired directly from bacteria or archaea, plus an additional 22 genes in which Entamoeba plus one other eukaryote are nested among bacteria and/or archaea. These genes may make good candidates for novel therapeutics, as drugs targeting these genes are less likely to impact the human host. Although we recognize the challenges of inferring intradomain transfers given systematic errors in gene trees, we find 109 genes supporting LGT from a eukaryote to Entamoeba spp., and 178 genes unique to Entamoeba spp. and one other eukaryotic taxon (i.e., presence/absence data). Inspection of these intradomain LGTs provide evidence of a common sister relationship between genes of Entamoeba (Amoebozoa) and parabasalids (Excavata). We speculate that this indicates a past close relationship (e.g., symbiosis) between ancestors of these extant lineages.

  20. Short hairpin RNA-mediated knockdown of protein expression in Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Singh Upinder

    2009-02-01

    Full Text Available Abstract Background Entamoeba histolytica is an intestinal protozoan parasite of humans. The genome has been sequenced, but the study of individual gene products has been hampered by the lack of the ability to generate gene knockouts. We chose to test the use of RNA interference to knock down gene expression in Entamoeba histolytica. Results An episomal vector-based system, using the E. histolytica U6 promoter to drive expression of 29-basepair short hairpin RNAs, was developed to target protein-encoding genes in E. histolytica. The short hairpin RNAs successfully knocked down protein levels of all three unrelated genes tested with this system: Igl, the intermediate subunit of the galactose- and N-acetyl-D-galactosamine-inhibitable lectin; the transcription factor URE3-BP; and the membrane binding protein EhC2A. Igl levels were reduced by 72%, URE3-BP by 89%, and EhC2A by 97%. Conclusion Use of the U6 promoter to drive expression of 29-basepair short hairpin RNAs is effective at knocking down protein expression for unrelated genes in Entamoeba histolytica, providing a useful tool for the study of this parasite.

  1. Bioconjugated fluorescent silica nanoparticles for the rapid detection of Entamoeba histolytica.

    Science.gov (United States)

    Hemadi, Ahmad; Ekrami, Alireza; Oormazdi, Hormozd; Meamar, Ahmad Reza; Akhlaghi, Lame; Samarbaf-Zadeh, Ali Reza; Razmjou, Elham

    2015-05-01

    Rapid detection of Entamoeba histolytica based on fluorescent silica nanoparticle (FSNP) indirect immunofluorescence microscopy was evaluated. Silica nanoparticles were synthesized using Stöber's method, with their surface activated to covalently bind to, and immobilize, protein A. For biolabeling, FSNP was added to conjugated E. histolytica trophozoites with monoclonal anti-E. histolytica IgG1 for microscopic observation of fluorescence. Fluorescent silica nanoparticle sensitivity was determined with axenically cultured E. histolytica serially diluted to seven concentrations. Specificity was evaluated using other intestinal protozoa. Fluorescent silica nanoparticles detected E. histolytica at the lowest tested concentration with no cross-reaction with Entamoeba dispar, Entamoeba moshkovskii, Blastocystis sp., or Giardia lamblia. Visualization of E. histolytica trophozoites with anti-E. histolytica antibody labeled with fluorescein isothiocyanate (FITC) was compared with that using anti-E. histolytica antibody bioconjugated FSNP. Although FITC and FSNP produced similar results, the amount of specific antibody required for FITC to induce fluorescence of similar intensity was fivefold that for FSNP. Fluorescent silica nanoparticles delivered a rapid, simple, cost-effective, and highly sensitive and specific method of detecting E. histolytica. Further study is needed before introducing FSNP for laboratory diagnosis of amoebiasis.

  2. Entamoeba histolytica induces cell death of HT29 colonic epithelial cells via NOX1-derived ROS.

    Science.gov (United States)

    Kim, Kyeong Ah; Kim, Ju Young; Lee, Young Ah; Min, Arim; Bahk, Young Yil; Shin, Myeong Heon

    2013-02-01

    Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoeba-induced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.

  3. Evidence for a "wattle and daub" model of the cyst wall of entamoeba.

    Science.gov (United States)

    Chatterjee, Anirban; Ghosh, Sudip K; Jang, Ken; Bullitt, Esther; Moore, Landon; Robbins, Phillips W; Samuelson, John

    2009-07-01

    The cyst wall of Entamoeba invadens (Ei), a model for the human pathogen Entamoeba histolytica, is composed of fibrils of chitin and three chitin-binding lectins called Jacob, Jessie3, and chitinase. Here we show chitin, which was detected with wheat germ agglutinin, is made in secretory vesicles prior to its deposition on the surface of encysting Ei. Jacob lectins, which have tandemly arrayed chitin-binding domains (CBDs), and chitinase, which has an N-terminal CBD, were each made early during encystation. These results are consistent with their hypothesized roles in cross-linking chitin fibrils (Jacob lectins) and remodeling the cyst wall (chitinase). Jessie3 lectins likely form the mortar or daub of the cyst wall, because 1) Jessie lectins were made late during encystation; 2) the addition to Jessie lectins to the cyst wall correlated with a marked decrease in the permeability of cysts to nucleic acid stains (DAPI) and actin-binding heptapeptide (phalloidin); and 3) recombinant Jessie lectins, expressed as a maltose-binding proteins in the periplasm of Escherichia coli, caused transformed bacteria to agglutinate in suspension and form a hard pellet that did not dissociate after centrifugation. Jessie3 appeared as linear forms and rosettes by negative staining of secreted recombinant proteins. These findings provide evidence for a "wattle and daub" model of the Entamoeba cyst wall, where the wattle or sticks (chitin fibrils likely cross-linked by Jacob lectins) is constructed prior to the addition of the mortar or daub (Jessie3 lectins).

  4. Entamoeba invadens: Identification of a SERCA protein and effect of SERCA inhibitors on encystation.

    Science.gov (United States)

    Martínez-Higuera, Aarón; Herrera-Martínez, Mayra; Chávez-Munguía, Bibiana; Valle-Solís, Martha; Muñiz-Lino, Marcos A; Cázares-Apátiga, Javier; Rodríguez, Mario A

    2015-12-01

    Calcium has an important role on signaling of different cellular processes, including growth and differentiation. Signaling by calcium also has an essential function in pathogenesis and differentiation of the protozoan parasites Entamoeba histolytica and Entamoeba invadens. However, the proteins of these parasites that regulate the cytoplasmic concentration of this ion are poorly studied. In eukaryotic cells, the calcium-ATPase of the SERCA type plays an important role in calcium homeostasis by catalyzing the active efflux of calcium from cytoplasm to endoplasmic reticulum. Here, we reported the identification of SERCA of E. invadens (EiSERCA). This protein contains a putative sequence for endoplasmic reticulum retention and all domains involved in calcium transport identified in mammalian SERCA. By immunofluorescence assays, an antibody against SERCA of E. histolytica detected EiSERCA in a vesicular network in the cytoplasm of E. invadens trophozoites, co-localizing with calreticulin. Interestingly, EiSERCA was redistributed close to plasma membrane during encystation, suggesting that this pump could participate in regulate the calcium concentration during this process. In addition, thapsigargin and cyclopiazonic acid, both specific inhibitors of SERCA, affected the number and structure of cysts, supporting the hypothesis that calcium flux mediated by SERCA has an important role in the life cycle of Entamoeba.

  5. Dietary Magnesium and Genetic Interactions in Diabetes and Related Risk Factors: A Brief Overview of Current Knowledge

    Directory of Open Access Journals (Sweden)

    Adela Hruby

    2013-12-01

    Full Text Available Nutritional genomics has exploded in the last decade, yielding insights—both nutrigenomic and nutrigenetic—into the physiology of dietary interactions and our genes. Among these are insights into the regulation of magnesium transport and homeostasis and mechanisms underlying magnesium’s role in insulin and glucose handling. Recent observational evidence has attempted to examine some promising research avenues on interaction between genetics and dietary magnesium in relation to diabetes and diabetes risk factors. This brief review summarizes the recent evidence on dietary magnesium’s role in diabetes and related traits in the presence of underlying genetic risk, and discusses future potential research directions.

  6. Genetic association analysis of 30 genes related to obesity in a European American population.

    Science.gov (United States)

    Li, P; Tiwari, H K; Lin, W-Y; Allison, D B; Chung, W K; Leibel, R L; Yi, N; Liu, N

    2014-05-01

    Obesity, which is frequently associated with diabetes, hypertension and cardiovascular diseases, is primarily the result of a net excess of caloric intake over energy expenditure. Human obesity is highly heritable, but the specific genes mediating susceptibility in non-syndromic obesity remain unclear. We tested candidate genes in pathways related to food intake and energy expenditure for association with body mass index (BMI). We reanalyzed 355 common genetic variants of 30 candidate genes in seven molecular pathways related to obesity in 1982 unrelated European Americans from the New York Cancer Project. Data were analyzed by using a Bayesian hierarchical generalized linear model. The BMIs were log-transformed and then adjusted for covariates, including age, age(2), gender and diabetes status. The single-nucleotide polymorphisms (SNPs) were modeled as additive effects. With the stipulated adjustments, nine SNPs in eight genes were significantly associated with BMI: ghrelin (GHRL; rs35683), agouti-related peptide (AGRP; rs5030980), carboxypeptidase E (CPE; rs1946816 and rs4481204), glucagon-like peptide-1 receptor (GLP1R; rs2268641), serotonin receptors (HTR2A; rs912127), neuropeptide Y receptor (NPY5R;Y5R1c52), suppressor of cytokine signaling 3 (SOCS3; rs4969170) and signal transducer and activator of transcription 3 (STAT3; rs4796793). We also found a gender-by-SNP interaction (rs1745837 in HTR2A), which indicated that variants in the gene HTR2A had a stronger association with BMI in males. In addition, NPY1R was detected as having a significant gene effect even though none of the SNPs in this gene was significant. Variations in genes AGRP, CPE, GHRL, GLP1R, HTR2A, NPY1R, NPY5R, SOCS3 and STAT3 showed modest associations with BMI in European Americans. The pathways in which these genes participate regulate energy intake, and thus these associations are mechanistically plausible in this context.

  7. Possible effects of (trans)gene flow from crops on the genetic diversity from landraces and wild relatives.

    Science.gov (United States)

    Gepts, Paul; Papa, Roberto

    2003-01-01

    Gene flow is a potential concern associated with the use of transgenic crops because it could affect genetic diversity of related landraces and wild relatives. This concern has taken on added importance with the looming introduction of transgenic crops in centers of crop domestication (Mexico, China) and those producing pharmaceutical compounds. For gene flow to take place among cultivars and their wild relatives, several steps have to be fulfilled, including the presence of cultivars or wild relatives within pollen or seed dispersal range, the ability to produce viable and fertile hybrids, at least partial overlap in flowering time, actual gene flow by pollen or seed, and the establishment of crop genes in the domesticated or wild recipient populations. In contrast with domestication genes, which often make crops less adapted to natural ecosystems, transgenes frequently represent gains of function, which might release wild relatives from constraints that limit their fitness. In most sexually reproducing organisms, the chromosomal region affected by selection of a single gene amounts to a small percentage of the total genome size. Because of gene flow, the level of genetic diversity present in the domesticated gene pool becomes a crucial factor affecting the genetic diversity of the wild gene pool. For some crops, such as cotton and maize, the introduction of transgenic technologies has led to a consolidation of the seed industry and a reduction in the diversity of the elite crop gene pool. Thus, diversity in improved varieties grown by farmers needs to be monitored. Several areas deserve further study, such as the actual magnitude of gene flow and its determinants in different agroecosystems, the long-term effects of gene flow on genetic diversity both across gene pools and within genomes, the expression of transgenes in new genetic backgrounds, and the effects of socio-economic factors on genetic diversity.

  8. Genetic determinants of serum vitamin B12 and their relation to body mass index

    DEFF Research Database (Denmark)

    Allin, Kristine H; Friedrich, Nele; Pietzner, Maik

    2016-01-01

    for associations between (1) serum vitamin B12 levels and body mass index (BMI), (2) genetic variants and serum vitamin B12 levels, and (3) genetic variants and BMI. The effect of a genetically determined decrease in serum vitamin B12 on BMI was estimated by instrumental variable regression. Decreased serum...... vitamin B12 associated with increased BMI (P genetic risk score based on eight vitamin B12 associated variants associated strongly with serum vitamin B12 (P ... was associated with a 0.09 kg/m(2) (95% CI 0.05; 0.13) increase in BMI (P = 3 × 10(-5)), wh