Sample records for brucei gambiense causative

  1. Domestic animals as potential reservoir hosts of Trypanosoma brucei gambiense in sleeping sickness foci in Cameroon

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    Njiokou F.


    Full Text Available An explanation of the endemic nature and/or the resurgence of Human African Trypanosomiasis (HAT in the historic foci in West and Central Africa may be the existence of an animal reservoir. In some HAT foci, pigs were found infected by Trypanosoma brucei gambiense but the implication of the other domestic animals was not quite evaluated. This study aims to determine the prevalence of T. b. gambiense in domestic animal species (goat, sheep, pig and dog commonly found in the four active HAT foci in Cameroon (Bipindi, Fontem, Campo and Doumé. Blood samples were collected from 307 pigs, 264 goats, 267 sheep and 37 dogs and used for parasitological (QBC, immunological (LiTat 1.3 CATT and molecular (PCR analyses. QBC detected trypanosomes in 3.88 % domestic animals while 22.7 % were sero-positive with LiTat 1.3 CATT tests. Of the 875 animals analysed, 174 (19.88 % harboured T. brucei s.l. DNA, found in each of the four types of animal and in the four localities. The infection rate significantly differed among the animal species (p < 0.0001 and localities (p < 0.0001. The PCR also revealed T. b. gambiense group 1 DNA in 27 (3.08 % domestic animals. The specific infection rates were as follows: sheep (6.74 %, goats (3.08 %, pigs (0.32 % and dogs (0 %. T. b. gambiense was found in 8 (3.92 % animals from Bipindi, 15 (4.83 % from Campo, 4 (2.59 % from Fontem-Center and none from Doumé. The infection rates significantly differed between the localities, and correlated with the intensity of HAT transmission in the foci.

  2. Trypanosoma brucei gambiense Type 1 populations from human patients are clonal and display geographical genetic differentiation. (United States)

    Morrison, Liam J; Tait, Andy; McCormack, Gillian; Sweeney, Lindsay; Black, Alana; Truc, Philippe; Likeufack, Anne C L; Turner, C Michael; MacLeod, Annette


    We have rigorously tested the hypothesis that Trypanosoma brucei gambiense Type 1 is composed of genetically homogenous populations by examining the parasite population present in Human African Trypanosomiasis (HAT) patients from the Democratic Republic of Congo (DRC) and Cameroon (CAM). We amplified eight microsatellite markers by PCR directly from blood spots on FTA filters, thereby avoiding the significant parasite selection inherent in the traditional isolation techniques of rodent inoculation or in vitro culture. All microsatellite markers were polymorphic, although for four markers there was only polymorphism between the DRC and CAM populations, not within populations, suggesting very limited genetic exchange. Within the largest population from the DRC, Hardy-Weinberg equilibrium is not evident at any loci. This evidence suggests a clonal population. However, there was significant sub-structuring between the DRC and CAM samples (F(ST) = 0.32), indicating that Trypanosoma brucei gambiense Type 1 has genetically distinct clades. The data combine to indicate that genetic exchange plays a very limited role. The finding of distinct clades in different places suggests the possibility that samples from humans with clinical signs represent clonal expansions from an underlying population that requires identifying and characterising.

  3. Diversity and spation distribution of vectors and hosts of T. brucei gambiense in forest zones of Southern Cameroon: Epidemiological implications

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    Massussi, J.A.; Mbida Mbida, J.A.; Djieto-Lordon, C.; Njiokou, F.; Laveissière, C.; Ploeg, van der J.D.


    Host and vector distribution of Trypanosoma brucei gambiense was studied in relation to habitat types and seasons. Six (19.35%) of the 31 mammal species recorded in Bipindi were reservoir hosts. Cercopithecus nictitans was confined to the undisturbed forest and the low intensive shifting cultivation

  4. Molecular Evidence of a Trypanosoma brucei gambiense Sylvatic Cycle in the Human African Trypanosomiasis Foci of Equatorial Guinea

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    Carlos eCordon-Obras


    Full Text Available Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of Gambiense trypanosomiasis.

  5. Trypanosoma brucei gambiense adaptation to different mammalian sera is associated with VSG expression site plasticity.

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    Carlos Cordon-Obras

    Full Text Available Trypanosoma brucei gambiense infection is widely considered an anthroponosis, although it has also been found in wild and domestic animals. Thus, fauna could act as reservoir, constraining the elimination of the parasite in hypo-endemic foci. To better understand the possible maintenance of T. b. gambiense in local fauna and investigate the molecular mechanisms underlying adaptation, we generated adapted cells lines (ACLs by in vitro culture of the parasites in different mammalian sera. Using specific antibodies against the Variant Surface Glycoproteins (VSGs we found that serum ACLs exhibited different VSG variants when maintained in pig, goat or human sera. Although newly detected VSGs were independent of the sera used, the consistent appearance of different VSGs suggested remodelling of the co-transcribed genes at the telomeric Expression Site (VSG-ES. Thus, Expression Site Associated Genes (ESAGs sequences were analysed to investigate possible polymorphism selection. ESAGs 6 and 7 genotypes, encoding the transferrin receptor (TfR, expressed in different ACLs were characterised. In addition, we quantified the ESAG6/7 mRNA levels and analysed transferrin (Tf uptake. Interestingly, the best growth occurred in pig and human serum ACLs, which consistently exhibited a predominant ESAG7 genotype and higher Tf uptake than those obtained in calf and goat sera. We also detected an apparent selection of specific ESAG3 genotypes in the pig and human serum ACLs, suggesting that other ESAGs could be involved in the host adaptation processes. Altogether, these results suggest a model whereby VSG-ES remodelling allows the parasite to express a specific set of ESAGs to provide selective advantages in different hosts. Finally, pig serum ACLs display phenotypic adaptation parameters closely related to human serum ACLs but distinct to parasites grown in calf and goat sera. These results suggest a better suitability of swine to maintain T. b. gambiense infection

  6. In vitro investigation of Brazilian Cerrado plant extract activity against Plasmodium falciparum, Trypanosoma cruzi and T. brucei gambiense. (United States)

    Charneau, Sébastien; de Mesquita, Mariana Laundry; Bastos, Izabela Marques Dourado; Santana, Jaime Martins; de Paula, José Elias; Grellier, Philippe; Espindola, Laila Salmen


    The threatened Brazilian Cerrado biome is an important biodiversity hotspot but still few explored that constitutes a potential reservoir of molecules to treat infectious diseases. We selected eight Cerrado plant species for screening against the erythrocytic stages of Plasmodium falciparum, human intracellular stages of Trypanosoma cruzi and bloodstream forms of T. brucei gambiense, and for their cytotoxicity upon the rat L6-myoblast cell line. Bioassays were performed with 37 hexane, ethyl acetate and ethanol extracts prepared from different plant organs. Activities against parasites were observed for 24 extracts: 9 with anti-P. falciparum, 4 with anti-T. cruzi and 11 with anti-T. brucei gambiense activities. High anti-protozoal activity (IC50 values Cerrado conservation and sustainable development.

  7. Untreated human infections by Trypanosoma brucei gambiense are not 100% fatal.

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    Vincent Jamonneau

    Full Text Available The final outcome of infection by Trypanosoma brucei gambiense, the main agent of sleeping sickness, has always been considered as invariably fatal. While scarce and old reports have mentioned cases of self-cure in untreated patients, these studies suffered from the lack of accurate diagnostic tools available at that time. Here, using the most specific and sensitive tools available to date, we report on a long-term follow-up (15 years of a cohort of 50 human African trypanosomiasis (HAT patients from the Ivory Coast among whom 11 refused treatment after their initial diagnosis. In 10 out of 11 subjects who continued to refuse treatment despite repeated visits, parasite clearance was observed using both microscopy and polymerase chain reaction (PCR. Most of these subjects (7/10 also displayed decreasing serological responses, becoming progressively negative to trypanosome variable antigens (LiTat 1.3, 1.5 and 1.6. Hence, in addition to the "classic" lethal outcome of HAT, we show that alternative natural progressions of HAT may occur: progression to an apparently aparasitaemic and asymptomatic infection associated with strong long-lasting serological responses and progression to an apparently spontaneous resolution of infection (with negative results in parasitological tests and PCR associated with a progressive drop in antibody titres as observed in treated cases. While this study does not precisely estimate the frequency of the alternative courses for this infection, it is noteworthy that in the field national control programs encounter a significant proportion of subjects displaying positive serologic test results but negative results in parasitological testing. These findings demonstrate that a number of these subjects display such infection courses. From our point of view, recognising that trypanotolerance exists in humans, as is now widely accepted for animals, is a major step forward for future research in the field of HAT.

  8. Chimerization at the AQP2–AQP3 locus is the genetic basis of melarsoprol–pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates

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    Fabrice E. Graf


    Full Text Available Aquaglyceroporin-2 is a known determinant of melarsoprol–pentamidine cross-resistance in Trypanosoma brucei brucei laboratory strains. Recently, chimerization at the AQP2–AQP3 tandem locus was described from melarsoprol–pentamidine cross-resistant Trypanosoma brucei gambiense isolates from sleeping sickness patients in the Democratic Republic of the Congo. Here, we demonstrate that reintroduction of wild-type AQP2 into one of these isolates fully restores drug susceptibility while expression of the chimeric AQP2/3 gene in aqp2–aqp3 null T. b. brucei does not. This proves that AQP2–AQP3 chimerization is the cause of melarsoprol–pentamidine cross-resistance in the T. b. gambiense isolates.

  9. Chimerization at the AQP2-AQP3 locus is the genetic basis of melarsoprol-pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates. (United States)

    Graf, Fabrice E; Baker, Nicola; Munday, Jane C; de Koning, Harry P; Horn, David; Mäser, Pascal


    Aquaglyceroporin-2 is a known determinant of melarsoprol-pentamidine cross-resistance in Trypanosoma brucei brucei laboratory strains. Recently, chimerization at the AQP2-AQP3 tandem locus was described from melarsoprol-pentamidine cross-resistant Trypanosoma brucei gambiense isolates from sleeping sickness patients in the Democratic Republic of the Congo. Here, we demonstrate that reintroduction of wild-type AQP2 into one of these isolates fully restores drug susceptibility while expression of the chimeric AQP2/3 gene in aqp2-aqp3 null T. b. brucei does not. This proves that AQP2-AQP3 chimerization is the cause of melarsoprol-pentamidine cross-resistance in the T. b. gambiense isolates.

  10. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model

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    Maina Ngotho


    Full Text Available Human African trypanosomiasis (HAT is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP and polymerase chain reaction (PCR in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF, saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

  11. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model. (United States)

    Ngotho, Maina; Kagira, John Maina; Gachie, Beatrice Muthoni; Karanja, Simon Muturi; Waema, Maxwell Wambua; Maranga, Dawn Nyawira; Maina, Naomi Wangari


    Human African trypanosomiasis (HAT) is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR) in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF), saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

  12. Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol.

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    Fabrice E Graf

    Full Text Available The predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Trypanosoma brucei mutants. But clinical isolates, especially of T. b. gambiense, are less amenable to experimental investigation since they do not readily grow in culture without prior adaptation. Here we analyze a selected panel of 16 T. brucei ssp. field isolates that (i have been adapted to axenic in vitro cultivation and (ii mostly stem from treatment-refractory cases. For each isolate, we quantify the sensitivity to melarsoprol, pentamidine, and diminazene, and sequence the genomic loci of the transporter genes TbAT1 and TbAQP2. The former encodes the well-characterized aminopurine permease P2 which transports several trypanocides including melarsoprol, pentamidine, and diminazene. We find that diminazene-resistant field isolates of T. b. brucei and T. b. rhodesiense carry the same set of point mutations in TbAT1 that was previously described from lab mutants. Aquaglyceroporin 2 has only recently been identified as a second transporter involved in melarsoprol/pentamidine cross-resistance. Here we describe two different kinds of TbAQP2 mutations found in T. b. gambiense field isolates: simple loss of TbAQP2, or loss of wild-type TbAQP2 allele combined with the formation of a novel type of TbAQP2/3 chimera. The identified mutant T. b. gambiense are 40- to 50-fold less sensitive to pentamidine and 3- to 5-times less sensitive to melarsoprol than the reference isolates. We thus demonstrate for the first time that rearrangements of the TbAQP2/TbAQP3 locus accompanied by TbAQP2 gene loss also occur in the field, and that the T. b. gambiense carrying such mutations correlate with a significantly reduced susceptibility to pentamidine and melarsoprol.

  13. Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. (United States)

    Graf, Fabrice E; Ludin, Philipp; Wenzler, Tanja; Kaiser, Marcel; Brun, Reto; Pyana, Patient Pati; Büscher, Philippe; de Koning, Harry P; Horn, David; Mäser, Pascal


    The predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Trypanosoma brucei mutants. But clinical isolates, especially of T. b. gambiense, are less amenable to experimental investigation since they do not readily grow in culture without prior adaptation. Here we analyze a selected panel of 16 T. brucei ssp. field isolates that (i) have been adapted to axenic in vitro cultivation and (ii) mostly stem from treatment-refractory cases. For each isolate, we quantify the sensitivity to melarsoprol, pentamidine, and diminazene, and sequence the genomic loci of the transporter genes TbAT1 and TbAQP2. The former encodes the well-characterized aminopurine permease P2 which transports several trypanocides including melarsoprol, pentamidine, and diminazene. We find that diminazene-resistant field isolates of T. b. brucei and T. b. rhodesiense carry the same set of point mutations in TbAT1 that was previously described from lab mutants. Aquaglyceroporin 2 has only recently been identified as a second transporter involved in melarsoprol/pentamidine cross-resistance. Here we describe two different kinds of TbAQP2 mutations found in T. b. gambiense field isolates: simple loss of TbAQP2, or loss of wild-type TbAQP2 allele combined with the formation of a novel type of TbAQP2/3 chimera. The identified mutant T. b. gambiense are 40- to 50-fold less sensitive to pentamidine and 3- to 5-times less sensitive to melarsoprol than the reference isolates. We thus demonstrate for the first time that rearrangements of the TbAQP2/TbAQP3 locus accompanied by TbAQP2 gene loss also occur in the field, and that the T. b. gambiense carrying such mutations correlate with a significantly reduced susceptibility to pentamidine and melarsoprol.

  14. Trypanosoma brucei gambiense group 1 is distinguished by a unique amino acid substitution in the HpHb receptor implicated in human serum resistance.

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    Rebecca E Symula

    Full Text Available Trypanosoma brucei rhodesiense (Tbr and T. b. gambiense (Tbg, causative agents of Human African Trypanosomiasis (sleeping sickness in Africa, have evolved alternative mechanisms of resisting the activity of trypanosome lytic factors (TLFs, components of innate immunity in human serum that protect against infection by other African trypanosomes. In Tbr, lytic activity is suppressed by the Tbr-specific serum-resistance associated (SRA protein. The mechanism in Tbg is less well understood but has been hypothesized to involve altered activity and expression of haptoglobin haemoglobin receptor (HpHbR. HpHbR has been shown to facilitate internalization of TLF-1 in T.b. brucei (Tbb, a member of the T. brucei species complex that is susceptible to human serum. By evaluating the genetic variability of HpHbR in a comprehensive geographical and taxonomic context, we show that a single substitution that replaces leucine with serine at position 210 is conserved in the most widespread form of Tbg (Tbg group 1 and not found in related taxa, which are either human serum susceptible (Tbb or known to resist lysis via an alternative mechanism (Tbr and Tbg group 2. We hypothesize that this single substitution contributes to reduced uptake of TLF and thus may play a key role in conferring serum resistance to Tbg group 1. In contrast, similarity in HpHbR sequence among isolates of Tbg group 2 and Tbb/Tbr provides further evidence that human serum resistance in Tbg group 2 is likely independent of HpHbR function.

  15. Murine Models for Trypanosoma brucei gambiense disease progression--from silent to chronic infections and early brain tropism.

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    Christiane Giroud

    Full Text Available Human African trypanosomiasis (HAT caused by Trypanosoma brucei gambiense remains highly prevalent in west and central Africa and is lethal if left untreated. The major problem is that the disease often evolves toward chronic or asymptomatic forms with low and fluctuating parasitaemia producing apparently aparasitaemic serological suspects who remain untreated because of the toxicity of the chemotherapy. Whether the different types of infections are due to host or parasite factors has been difficult to address, since T. b. gambiense isolated from patients is often not infectious in rodents thus limiting the variety of isolates.T. b. gambiense parasites were outgrown directly from the cerebrospinal fluid of infected patients by in vitro culture and analyzed for their molecular polymorphisms. Experimental murine infections showed that these isolates could be clustered into three groups with different characteristics regarding their in vivo infection properties, immune response and capacity for brain invasion. The first isolate induced a classical chronic infection with a fluctuating blood parasitaemia, an invasion of the central nervous system (CNS, a trypanosome specific-antibody response and death of the animals within 6-8 months. The second group induced a sub-chronic infection resulting in a single wave of parasitaemia after infection, followed by a low parasitaemia with no parasites detected by microscope observations of blood but detected by PCR, and the presence of a specific antibody response. The third isolate induced a silent infection characterised by the absence of microscopically detectable parasites throughout, but infection was detectable by PCR during the whole course of infection. Additionally, specific antibodies were barely detectable when mice were infected with a low number of this group of parasites. In both sub-chronic and chronic infections, most of the mice survived more than one year without major clinical symptoms

  16. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

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    E DeJesus

    Full Text Available Critical to human innate immunity against African trypanosomes is a minor subclass of human high-density lipoproteins, termed Trypanosome Lytic Factor-1 (TLF-1. This primate-specific molecule binds to a haptoglobin-hemoglobin receptor (HpHbR on the surface of susceptible trypanosomes, initiating a lytic pathway. Group 1 Trypanosoma brucei gambiense causes human African Trypanosomiasis (HAT, escaping TLF-1 killing due to reduced uptake. Previously, we found that group 1 T. b. gambiense HpHbR (TbgHpHbR mRNA levels were greatly reduced and the gene contained substitutions within the open reading frame. Here we show that a single, highly conserved amino acid in the TbgHpHbR ablates high affinity TLF-1 binding and subsequent endocytosis, thus evading TLF-1 killing. In addition, we show that over-expression of TbgHpHbR failed to rescue TLF-1 susceptibility. These findings suggest that the single substitution present in the TbgHpHbR directly contributes to the reduced uptake and resistance to TLF-1 seen in these important human pathogens.

  17. The miRNA and mRNA Signatures of Peripheral Blood Cells in Humans Infected with Trypanosoma brucei gambiense.

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    Smiths Lueong

    Full Text Available Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II and without (stage I brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II, 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology.

  18. Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo.

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    Patient Pyana Pati


    Full Text Available Sleeping sickness caused by Trypanosoma brucei (T.b. gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was the situation in Mbuji-Mayi, East Kasai Province in the Democratic Republic of the Congo with a 57% relapse rate compared to a 5% relapse rate in Masi-Manimba, Bandundu Province. The present study aimed at investigating the mechanisms underlying the high relapse rate in Mbuji-Mayi using an extended collection of recently isolated T.b. gambiense strains from Mbuji-Mayi and from Masi-Manimba.Forty five T.b. gambiense strains were used. Forty one were isolated from patients that were cured or relapsed after melarsoprol treatment in Mbuji-Mayi. In vivo drug sensitivity tests provide evidence of reduced melarsoprol sensitivity in these strains. This reduced melarsoprol sensitivity was not attributable to mutations in TbAT1. However, in all these strains, irrespective of the patient treatment outcome, the two aquaglyceroporin (AQP 2 and 3 genes are replaced by chimeric AQP2/3 genes that may be associated with resistance to pentamidine and melarsoprol. The 4 T.b. gambiense strains isolated in Masi-Manimba contain both wild-type AQP2 and a different chimeric AQP2/3. These findings suggest that the reduced in vivo melarsoprol sensitivity of the Mbuji-Mayi strains and the high relapse rates in that sleeping sickness focus are caused by mutations in the AQP2/AQP3 locus and not by mutations in TbAT1.We conclude that mutations in the TbAQP2/3 locus of the local T.b. gambiense strains may explain the high melarsoprol relapse rates in the Mbuji-Mayi focus but other factors must also be involved in the treatment outcome of individual patients.

  19. Screening North American plant extracts in vitro against Trypanosoma brucei, the causative agent for Human African Trypanosomiasis (United States)

    Natural products extracts from 522 plants collected from different parts of the North America were screened in vitro against trypamastigote forms of Trypanosoma brucei. The active extracts(150)with >90% inhibition at 20ug/mL concentrations from the plants namely, Alnus rubra, Hoita macrostachya, S...

  20. Trypanosoma brucei CYP51: Essentiality and Targeting Therapy in an Experimental Model (United States)

    Dauchy, Frédéric-Antoine; Bonhivers, Mélanie; Landrein, Nicolas; Dacheux, Denis; Courtois, Pierrette; Lauruol, Florian; Daulouède, Sylvie


    Trypanosoma brucei gambiense is the main causative agent of Human African Trypanosomiasis (HAT), also known as sleeping sickness. Because of limited alternatives and treatment toxicities, new therapeutic options are urgently needed for patients with HAT. Sterol 14alpha-demethylase (CYP51) is a potential drug target but its essentiality has not been determined in T. brucei. We used a tetracycline-inducible RNAi system to assess the essentiality of CYP51 in T. brucei bloodstream form (BSF) cells and we evaluated the effect of posaconazole, a well-tolerated triazole drug, within a panel of virulent strains in vitro and in a murine model. Expression of CYP51 in several T. brucei cell lines was demonstrated by western blot and its essentiality was demonstrated by RNA interference (CYP51RNAi) in vitro. Following reduction of TbCYP51 expression by RNAi, cell growth was reduced and eventually stopped compared to WT or non-induced cells, showing the requirement of CYP51 in T. brucei. These phenotypes were rescued by addition of ergosterol. Additionally, CYP51RNAi induction caused morphological defects with multiflagellated cells (ptrypanosomiasis. PMID:27855164

  1. Wild chimpanzees are infected by Trypanosoma brucei

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    Milan Jirků


    Finally, we demonstrated that the mandrill serum was able to efficiently lyse T. b. brucei and T. b. rhodesiense, and to some extent T. b. gambiense, while the chimpanzee serum failed to lyse any of these subspecies.

  2. An Overview of Trypanosoma brucei Infections: An Intense Host–Parasite Interaction (United States)

    Ponte-Sucre, Alicia


    Trypanosoma brucei rhodesiense and T. brucei gambiense, the causative agents of Human African Trypanosomiasis, are transmitted by tsetse flies. Within the vector, the parasite undergoes through transformations that prepares it to infect the human host. Sequentially these developmental stages are the replicative procyclic (in which the parasite surface is covered by procyclins) and trypo-epimastigote forms, as well as the non-replicative, infective, metacyclic form that develops in the vector salivary glands. As a pre-adaptation to their life in humans, metacyclic parasites begin to express and be densely covered by the Variant Surface Glycoprotein (VSG). Once the metacyclic form invades the human host the parasite develops into the bloodstream form. Herein the VSG triggers a humoral immune response. To avoid this humoral response, and essential for survival while in the bloodstream, the parasite changes its cover periodically and sheds into the surroundings the expressed VSG, thus evading the consequences of the immune system activation. Additionally, tools comparable to quorum sensing are used by the parasite for the successful parasite transmission from human to insect. On the other hand, the human host promotes clearance of the parasite triggering innate and adaptive immune responses and stimulating cytokine and chemokine secretion. All in all, the host–parasite interaction is extremely active and leads to responses that need multiple control sites to develop appropriately. PMID:28082973

  3. Mechanism of Trypanosoma brucei gambiense resistance to human serum

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    Uzureau, Pierrick; Uzureau, Sophie; Lecordier, Laurence


    GP), which prevents APOL1 toxicity and induces stiffening of membranes upon interaction with lipids. Two additional features contribute to resistance to TLFs: reduction of sensitivity to APOL1 requiring cysteine protease activity, and TbHpHbR inactivation due to a L210S substitution. According...

  4. Structural and Functional Highlights of Vacuolar Soluble Protein 1 from Pathogen Trypanosoma brucei brucei. (United States)

    Jamwal, Abhishek; Round, Adam R; Bannwarth, Ludovic; Venien-Bryan, Catherine; Belrhali, Hassan; Yogavel, Manickam; Sharma, Amit


    Trypanosoma brucei (T. brucei) is responsible for the fatal human disease called African trypanosomiasis, or sleeping sickness. The causative parasite, Trypanosoma, encodes soluble versions of inorganic pyrophosphatases (PPase), also called vacuolar soluble proteins (VSPs), which are localized to its acidocalcisomes. The latter are acidic membrane-enclosed organelles rich in polyphosphate chains and divalent cations whose significance in these parasites remains unclear. We here report the crystal structure of T. brucei brucei acidocalcisomal PPases in a ternary complex with Mg(2+) and imidodiphosphate. The crystal structure reveals a novel structural architecture distinct from known class I PPases in its tetrameric oligomeric state in which a fused EF hand domain arranges around the catalytic PPase domain. This unprecedented assembly evident from TbbVSP1 crystal structure is further confirmed by SAXS and TEM data. SAXS data suggest structural flexibility in EF hand domains indicative of conformational plasticity within TbbVSP1.

  5. Structural and Functional Highlights of Vacuolar Soluble Protein 1 from Pathogen Trypanosoma brucei brucei* (United States)

    Jamwal, Abhishek; Round, Adam R.; Bannwarth, Ludovic; Venien-Bryan, Catherine; Belrhali, Hassan; Yogavel, Manickam; Sharma, Amit


    Trypanosoma brucei (T. brucei) is responsible for the fatal human disease called African trypanosomiasis, or sleeping sickness. The causative parasite, Trypanosoma, encodes soluble versions of inorganic pyrophosphatases (PPase), also called vacuolar soluble proteins (VSPs), which are localized to its acidocalcisomes. The latter are acidic membrane-enclosed organelles rich in polyphosphate chains and divalent cations whose significance in these parasites remains unclear. We here report the crystal structure of T. brucei brucei acidocalcisomal PPases in a ternary complex with Mg2+ and imidodiphosphate. The crystal structure reveals a novel structural architecture distinct from known class I PPases in its tetrameric oligomeric state in which a fused EF hand domain arranges around the catalytic PPase domain. This unprecedented assembly evident from TbbVSP1 crystal structure is further confirmed by SAXS and TEM data. SAXS data suggest structural flexibility in EF hand domains indicative of conformational plasticity within TbbVSP1. PMID:26494625

  6. 3-(Oxazolo[4,5-b]pyridin-2-yl)anilides as a novel class of potent inhibitors for the kinetoplastid Trypanosoma brucei, the causative agent for human African trypanosomiasis. (United States)

    Ferrins, Lori; Rahmani, Raphaël; Sykes, Melissa L; Jones, Amy J; Avery, Vicky M; Teston, Eliott; Almohaywi, Basmah; Yin, JieXiang; Smith, Jason; Hyland, Chris; White, Karen L; Ryan, Eileen; Campbell, Michael; Charman, Susan A; Kaiser, Marcel; Baell, Jonathan B


    A whole organism high-throughput screen of approximately 87,000 compounds against Trypanosoma brucei brucei led to the recent discovery of several novel compound classes with low micromolar activity against this organism and without appreciable cytotoxicity to mammalian cells. Herein we report a structure-activity relationship (SAR) investigation around one of these hit classes, the 3-(oxazolo[4,5-b]pyridin-2-yl)anilides. Sharp SAR is revealed, with our most active compound (5) exhibiting an IC₅₀ of 91 nM against the human pathogenic strain T.b. rhodesiense and being more than 700 times less toxic towards the L6 mammalian cell line. Physicochemical properties are attractive for many compounds in this series. For the most potent representatives, we show that solubility and metabolic stability are key parameters to target during future optimisation.

  7. Gambiense human african trypanosomiasis and immunological memory: effect on phenotypic lymphocyte profiles and humoral immunity. (United States)

    Lejon, Veerle; Mumba Ngoyi, Dieudonné; Kestens, Luc; Boel, Luc; Barbé, Barbara; Kande Betu, Victor; van Griensven, Johan; Bottieau, Emmanuel; Muyembe Tamfum, Jean-Jacques; Jacobs, Jan; Büscher, Philippe


    In mice, experimental infection with Trypanosoma brucei causes decreased bone marrow B-cell development, abolished splenic B-cell maturation and loss of antibody mediated protection including vaccine induced memory responses. Nothing is known about this phenomenon in human African trypanosomiasis (HAT), but if occurring, it would imply the need of revaccination of HAT patients after therapy and abolish hope for a HAT vaccine. The effect of gambiense HAT on peripheral blood memory T- and B-cells and on innate and vaccine induced antibody levels was examined. The percentage of memory B- and T-cells was quantified in peripheral blood, prospectively collected in DR Congo from 117 Trypanosoma brucei gambiense infected HAT patients before and six months after treatment and 117 controls at the same time points. Antibodies against carbohydrate antigens on red blood cells and against measles were quantified. Before treatment, significantly higher percentages of memory B-cells, mainly T-independent memory B-cells, were observed in HAT patients compared to controls (CD20+CD27+IgM+, 13.0% versus 2.0%, p<0.001). The percentage of memory T-cells, mainly early effector/memory T-cells, was higher in HAT (CD3+CD45RO+CD27+, 19.4% versus 16.7%, p = 0.003). After treatment, the percentage of memory T-cells normalized, the percentage of memory B-cells did not. The median anti-red blood cell carbohydrate IgM level was one titer lower in HAT patients than in controls (p<0.004), and partially normalized after treatment. Anti-measles antibody concentrations were lower in HAT patients than in controls (medians of 1500 versus 2250 mIU/ml, p = 0.02), and remained so after treatment, but were above the cut-off level assumed to provide protection in 94.8% of HAT patients, before and after treatment (versus 98.3% of controls, p = 0.3). Although functionality of the B-cells was not verified, the results suggest that immunity was conserved in T.b. gambiense infected HAT patients and

  8. Trypanosoma brucei brucei: effects of ferrous iron and heme on ecto-nucleoside triphosphate diphosphohydrolase activity. (United States)

    Leite, Milane S; Thomaz, Rachel; Oliveira, José Henrique M; Oliveira, Pedro L; Meyer-Fernandes, José Roberto


    Trypanosoma brucei brucei is the causative agent of animal African trypanosomiasis, also called nagana. Procyclic vector form resides in the midgut of the tsetse fly, which feeds exclusively on blood. Hemoglobin digestion occurs in the midgut resulting in an intense release of free heme. In the present study we show that the magnesium-dependent ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase) activity of procyclic T. brucei brucei is inhibited by ferrous iron and heme. The inhibition of E-NTPDase activity by ferrous iron, but not by heme, was prevented by pre-incubation of cells with catalase. However, antioxidants that permeate cells, such as PEG-catalase and N-acetyl-cysteine prevented the inhibition of E-NTPDase by heme. Ferrous iron was able to induce an increase in lipid peroxidation, while heme did not. Therefore, both ferrous iron and heme can inhibit E-NTPDase activity of T. brucei brucei by means of formation of reactive oxygen species, but apparently acting through distinct mechanisms.

  9. Protective effect of humus extract against Trypanosoma brucei infection in mice. (United States)

    Kodama, Hiroshi; Denso; Okazaki, Fumi; Ishida, Saeko


    Humic substances are formed during the decomposition of organic matter in humus, and are found in many natural environments in which organic materials and microorganisms are present. Oral administration of humus extract to mice successfully induced effective protection against experimental challenge by the two subspecies, Trypanosoma brucei brucei and T. brucei gambiense. Mortality was most reduced among mice who received a 3% humus extract for 21 days in drinking water ad libitum. Spleen cells from humus-administered mice exhibited significant non-specific cytotoxic activity against L1210 mouse leukemia target cells. Also, spleen cells produced significantly higher amounts of Interferon-gamma when stimulated in vitro with Concanavalin A than cells from normal controls. These results clearly show that administration to mice of humus extract induced effective resistance against Trypanosoma infection. Enhancement of the innate immune system may be involved in host defense against trypanosomiasis.

  10. A luciferase based viability assay for ATP detection in 384-well format for high throughput whole cell screening of Trypanosoma brucei brucei bloodstream form strain 427

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    Avery Vicky M


    Full Text Available Abstract Background Human African Trypanosomiasis (HAT is caused by two trypanosome species, Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Current drugs available for the treatment of HAT have significant issues related to toxicity, administration regimes with limited effectiveness across species and disease stages, thus there is a considerable need to find alternative drugs. A well recognised approach to identify new drug candidates is high throughput screening (HTS of large compound library collections. Results We describe here the development of a luciferase based viability assay in 384-well plate format suitable for HTS of T.b.brucei. The parameters that were explored to determine the final HTS assay conditions are described in detail and include DMSO tolerability, Z', diluents and cell inoculum density. Reference compound activities were determined for diminazene, staurosporine and pentamidine and compared to previously published IC50 data obtained. The assay has a comparable sensitivity to reference drugs and is more cost effective than the 96-well format currently reported for T.b.brucei. Conclusion Due to the reproducibility and sensitivity of this assay it is recommended for potential HTS application. As it is commercially available this assay can also be utilised in many laboratories for both large and small scale screening.

  11. Representing Causation (United States)

    Wolff, Phillip


    The dynamics model, which is based on L. Talmy's (1988) theory of force dynamics, characterizes causation as a pattern of forces and a position vector. In contrast to counterfactual and probabilistic models, the dynamics model naturally distinguishes between different cause-related concepts and explains the induction of causal relationships from…

  12. Taxonomy Icon Data: Trypanosoma brucei [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Trypanosoma brucei Trypanosoma brucei Trypanosoma_brucei_L.png Trypanosoma_brucei_NL.png Trypanosoma_bruce...i_S.png Trypanosoma_brucei_NS.png ...

  13. Accuracy of individual rapid tests for serodiagnosis of gambiense sleeping sickness in West Africa.

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    Vincent Jamonneau


    Full Text Available Individual rapid tests for serodiagnosis (RDT of human African trypanosomiasis (HAT are particularly suited for passive screening and surveillance. However, so far, no large scale evaluation of RDTs has been performed for diagnosis of Trypanosoma brucei gambiense HAT in West Africa. The objective of this study was to assess the diagnostic accuracy of 2 commercial HAT-RDTs on stored plasma samples from West Africa.SD Bioline HAT and HAT Sero-K-Set were performed on 722 plasma samples originating from Guinea and Côte d'Ivoire, including 231 parasitologically confirmed HAT patients, 257 healthy controls, and 234 unconfirmed individuals whose blood tested antibody positive in the card agglutination test but negative by parasitological tests. Immune trypanolysis was performed as a reference test for trypanosome specific antibody presence. Sensitivities in HAT patients were respectively 99.6% for SD Bioline HAT, and 99.1% for HAT Sero-K-Set, specificities in healthy controls were respectively 87.9% and 88.3%. Considering combined positivity in both RDTs, increased the specificity significantly (p ≤ 0.0003 to 93.4%, while 98.7% sensitivity was maintained. Specificities in controls were 98.7-99.6% for the combination of one or two RDTs with trypanolysis, maintaining a sensitivity of at least 98.1%.The observed specificity of the single RDTs was relatively low. Serial application of SD Bioline HAT and HAT Sero-K-Set might offer superior specificity compared to a single RDT, maintaining high sensitivity. The combination of one or two RDTs with trypanolysis seems promising for HAT surveillance.

  14. Treatment options for second-stage gambiense human African trypanosomiasis. (United States)

    Eperon, Gilles; Balasegaram, Manica; Potet, Julien; Mowbray, Charles; Valverde, Olaf; Chappuis, François


    Treatment of second-stage gambiense human African trypanosomiasis relied on toxic arsenic-based derivatives for over 50 years. The availability and subsequent use of eflornithine, initially in monotherapy and more recently in combination with nifurtimox (NECT), has drastically improved the prognosis of treated patients. However, NECT logistic and nursing requirements remain obstacles to its deployment and use in peripheral health structures in rural sub-Saharan Africa. Two oral compounds, fexinidazole and SCYX-7158, are currently in clinical development. The main scope of this article is to discuss the potential impact of new oral therapies to improve diagnosis-treatment algorithms and patients' access to treatment, and to contribute to reach the objectives of the recently launched gambiense human African trypanosomiasis elimination program.

  15. Human and animal Trypanosomes in Cote d'Ivoire form a single breeding population.

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    Paul Capewell

    Full Text Available BACKGROUND: Trypanosoma brucei is the causative agent of African Sleeping Sickness in humans and contributes to the related veterinary disease, Nagana. T. brucei is segregated into three subspecies based on host specificity, geography and pathology. T. b. brucei is limited to animals (excluding some primates throughout sub-Saharan Africa and is non-infective to humans due to trypanolytic factors found in human serum. T. b. gambiense and T. b. rhodesiense are human infective sub-species. T. b. gambiense is the more prevalent human, causing over 97% of human cases. Study of T. b. gambiense is complicated in that there are two distinct groups delineated by genetics and phenotype. The relationships between the two groups and local T. b. brucei are unclear and may have a bearing on the evolution of the human infectivity traits. METHODOLOGY/PRINCIPAL FINDINGS: A collection of sympatric T. brucei isolates from Côte d'Ivoire, consisting of T. b. brucei and both groups of T. b. gambiense have previously been categorized by isoenzymes, RFLPs and Blood Incubation Infectivity Tests. These samples were further characterized using the group 1 specific marker, TgSGP, and seven microsatellites. The relationships between the T. b. brucei and T. b. gambiense isolates were determined using principal components analysis, neighbor-joining phylogenetics, STRUCTURE, FST, Hardy-Weinberg equilibrium and linkage disequilibrium. CONCLUSIONS/SIGNIFICANCE: Group 1 T. b. gambiense form a clonal genetic group, distinct from group 2 and T. b. brucei, whereas group 2 T. b. gambiense are genetically indistinguishable from local T. b. brucei. There is strong evidence for mating within and between group 2 T. b. gambiense and T. b. brucei. We found no evidence to support the hypothesis that group 2 T. b. gambiense are hybrids of group 1 and T. b. brucei, suggesting that human infectivity has evolved independently in groups 1 and 2 T. b. gambiense.

  16. Handling Uncertainty in Dynamic Models : The Pentose Phosphate Pathway in Trypanosoma brucei

    NARCIS (Netherlands)

    Kerkhoven, Eduard J.; Achcar, Fiona; Alibu, Vincent P.; Burchmore, Richard J.; Gilbert, Ian H.; Trybilo, Maciej; Driessen, Nicole N.; Gilbert, David; Breitling, Rainer; Bakker, Barbara M.; Barrett, Michael P.


    Dynamic models of metabolism can be useful in identifying potential drug targets, especially in unicellular organisms. A model of glycolysis in the causative agent of human African trypanosomiasis, Trypanosoma brucei, has already shown the utility of this approach. Here we add the pentose phosphate

  17. Trypanosoma brucei gambiense Spliced Leader RNA Is a More Specific Marker for Cure of Human African Trypanosomiasis Than T. b. gambiense DNA. (United States)

    Ilboudo, Hamidou; Camara, Oumou; Ravel, Sophie; Bucheton, Bruno; Lejon, Veerle; Camara, Mamadou; Kaboré, Jacques; Jamonneau, Vincent; Deborggraeve, Stijn


    To assess the efficacy of treatment for human African trypanosomiasis, accurate tests that can discriminate relapse from cure are needed. We report the first data that the spliced leader (SL) RNA is a more specific marker for cure of human African trypanosomiasis than parasite DNA. In blood samples obtained from 61 patients in whom human African trypanosomiasis was cured, SL RNA detection had specificities of 98.4%-100%, while DNA detection had a specificity of only 77%. Data from our proof-of-concept study show that SL RNA detection has high potential as a test of cure.

  18. Syndromic algorithms for detection of gambiense human African trypanosomiasis in South Sudan.

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    Jennifer J Palmer

    Full Text Available BACKGROUND: Active screening by mobile teams is considered the best method for detecting human African trypanosomiasis (HAT caused by Trypanosoma brucei gambiense but the current funding context in many post-conflict countries limits this approach. As an alternative, non-specialist health care workers (HCWs in peripheral health facilities could be trained to identify potential cases who need testing based on their symptoms. We explored the predictive value of syndromic referral algorithms to identify symptomatic cases of HAT among a treatment-seeking population in Nimule, South Sudan. METHODOLOGY/PRINCIPAL FINDINGS: Symptom data from 462 patients (27 cases presenting for a HAT test via passive screening over a 7 month period were collected to construct and evaluate over 14,000 four item syndromic algorithms considered simple enough to be used by peripheral HCWs. For comparison, algorithms developed in other settings were also tested on our data, and a panel of expert HAT clinicians were asked to make referral decisions based on the symptom dataset. The best performing algorithms consisted of three core symptoms (sleep problems, neurological problems and weight loss, with or without a history of oedema, cervical adenopathy or proximity to livestock. They had a sensitivity of 88.9-92.6%, a negative predictive value of up to 98.8% and a positive predictive value in this context of 8.4-8.7%. In terms of sensitivity, these out-performed more complex algorithms identified in other studies, as well as the expert panel. The best-performing algorithm is predicted to identify about 9/10 treatment-seeking HAT cases, though only 1/10 patients referred would test positive. CONCLUSIONS/SIGNIFICANCE: In the absence of regular active screening, improving referrals of HAT patients through other means is essential. Systematic use of syndromic algorithms by peripheral HCWs has the potential to increase case detection and would increase their participation in HAT

  19. Loop-Mediated Isothermal Amplification Test for Trypanosoma gambiense Group 1 with Stem Primers: A Molecular Xenomonitoring Test for Sleeping Sickness (United States)

    Mburugu, Gitonga N.


    The World Health Organization has targeted Human African Trypanosomiasis (HAT) for elimination by 2020 with zero incidence by 2030. To achieve and sustain this goal, accurate and easy-to-deploy diagnostic tests for Gambian trypanosomiasis which accounts for over 98% of reported cases will play a crucial role. Most needed will be tools for surveillance of pathogen in vectors (xenomonitoring) since population screening tests are readily available. The development of new tests is expensive and takes a long time while incremental improvement of existing technologies that have potential for xenomonitoring may offer a shorter pathway to tools for HAT surveillance. We have investigated the effect of including a second set of reaction accelerating primers (stem primers) to the standard T. brucei gambiense LAMP test format. The new test format was analyzed with and without outer primers. Amplification was carried out using Rotorgene 6000 and the portable ESE Quant amplification unit capable of real-time data output. The stem LAMP formats indicated shorter time to results (~8 min), were 10–100-fold more sensitive, and indicated higher diagnostic sensitivity and accuracy compared to the standard LAMP test. It was possible to confirm the predicted product using ESE melt curves demonstrating the potential of combining LAMP and real-time technologies as possible tool for HAT molecular xenomonitoring.

  20. Loop-Mediated Isothermal Amplification Test for Trypanosoma gambiense Group 1 with Stem Primers: A Molecular Xenomonitoring Test for Sleeping Sickness

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    Zablon K. Njiru


    Full Text Available The World Health Organization has targeted Human African Trypanosomiasis (HAT for elimination by 2020 with zero incidence by 2030. To achieve and sustain this goal, accurate and easy-to-deploy diagnostic tests for Gambian trypanosomiasis which accounts for over 98% of reported cases will play a crucial role. Most needed will be tools for surveillance of pathogen in vectors (xenomonitoring since population screening tests are readily available. The development of new tests is expensive and takes a long time while incremental improvement of existing technologies that have potential for xenomonitoring may offer a shorter pathway to tools for HAT surveillance. We have investigated the effect of including a second set of reaction accelerating primers (stem primers to the standard T. brucei gambiense LAMP test format. The new test format was analyzed with and without outer primers. Amplification was carried out using Rotorgene 6000 and the portable ESE Quant amplification unit capable of real-time data output. The stem LAMP formats indicated shorter time to results (~8 min, were 10–100-fold more sensitive, and indicated higher diagnostic sensitivity and accuracy compared to the standard LAMP test. It was possible to confirm the predicted product using ESE melt curves demonstrating the potential of combining LAMP and real-time technologies as possible tool for HAT molecular xenomonitoring.

  1. The natural progression of Gambiense sleeping sickness: what is the evidence?

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    Francesco Checchi

    Full Text Available Gambiense human African trypanosomiasis (HAT, sleeping sickness is widely assumed to be 100% pathogenic and fatal. However, reports to the contrary exist, and human trypano-tolerance has been postulated. Furthermore, there is uncertainty about the actual duration of both stage 1 and stage 2 infection, particularly with respect to how long a patient remains infectious. Understanding such basic parameters of HAT infection is essential for optimising control strategies based on case detection. We considered the potential existence and relevance of human trypano-tolerance, and explored the duration of infectiousness, through a review of published evidence on the natural progression of gambiense HAT in the absence of treatment, and biological considerations. Published reports indicate that most gambiense HAT cases are fatal if untreated. Self-resolving and asymptomatic chronic infections probably constitute a minority if they do indeed exist. Chronic carriage, however, deserves further study, as it could seed renewed epidemics after control programmes cease.

  2. The journey towards elimination of gambiense human African trypanosomiasis: not far, nor easy. (United States)

    Franco, J R; Simarro, P P; Diarra, A; Ruiz-Postigo, J A; Jannin, J G


    Considering the epidemic situation of gambiense human African trypanosomiasis (HAT) at the end of the twentieth century, the World Health Organization (WHO) and partners strengthened disease control and surveillance. Over the last 15 years, the activities implemented through the National Control Programmes have brought gambiense HAT under control and now its elimination is deemed as an achievable goal. In 2012, WHO targeted gambiense HAT for elimination as a public health problem by 2020. The final goal will be the sustainable disease elimination by 2030, defined as the interruption of the transmission of gambiense HAT. The elimination is considered feasible, because of the epidemiological vulnerability of the disease, the current state of control, the availability of strategies and tools and international commitment and political will. Integration of activities in the health system is needed to ensure the sustainability of the elimination. The development of user-friendly diagnostic and treatment tools will facilitate the integration process. Adequate funding is needed to implement activities, but also to support research that will make the elimination sustainable. A long-term commitment by donors is needed and ownership of the process by endemic countries is critical.

  3. A proteomics approach reveals molecular manipulators of distinct cellular processes in the salivary glands of Glossina m. morsitans in response to Trypanosoma b. brucei infections

    NARCIS (Netherlands)

    Kariithi, Henry M.; Boeren, Sjef; Murungi, Edwin K.; Vlak, Just M.; Abd-Alla, Adly M.M.


    Background: Glossina m. morsitans is the primary vector of the Trypanosoma brucei group, one of the causative agents of African trypanosomoses. The parasites undergo metacyclogenesis, i.e. transformation into the mammalian-infective metacyclic trypomastigote (MT) parasites, in the salivary glands

  4. Probabilistic Causation without Probability. (United States)

    Holland, Paul W.

    The failure of Hume's "constant conjunction" to describe apparently causal relations in science and everyday life has led to various "probabilistic" theories of causation of which the study by P. C. Suppes (1970) is an important example. A formal model that was developed for the analysis of comparative agricultural experiments…

  5. Localization of serum resistance-associated protein in Trypanosoma brucei rhodesiense and transgenic Trypanosoma brucei brucei. (United States)

    Bart, Jean-Mathieu; Cordon-Obras, Carlos; Vidal, Isabel; Reed, Jennifer; Perez-Pastrana, Esperanza; Cuevas, Laureano; Field, Mark C; Carrington, Mark; Navarro, Miguel


    African trypanosomes infect a broad range of mammals, but humans and some higher primates are protected by serum trypanosome lytic factors that contain apolipoprotein L1 (ApoL1). In the human-infective subspecies of Trypanosoma brucei, Trypanosoma brucei rhodesiense, a gene product derived from the variant surface glycoprotein gene family member, serum resistance-associated protein (SRA protein), protects against ApoL1-mediated lysis. Protection against trypanosome lytic factor requires the direct interaction between SRA protein and ApoL1 within the endocytic apparatus of the trypanosome, but some uncertainty remains as to the precise mechanism and location of this interaction. In order to provide more insight into the mechanism of SRA-mediated resistance to trypanosome lytic factor, we assessed the localization of SRA in T. b. rhodesiense EATRO3 using a novel monoclonal antibody raised against SRA together with a set of well-characterized endosomal markers. By three-dimensional deconvolved immunofluorescence single-cell analysis, combined with double-labelling immunoelectron microscopy, we found that ≈ 50% of SRA protein localized to the lysosome, with the remaining population being distributed through the endocytic pathway, but apparently absent from the flagellar pocket membrane. These data suggest that the SRA/trypanolytic factor interaction is intracellular, with the concentration within the endosomes potentially crucial for ensuring a high efficiency.

  6. Anti-trypanosomal effect of Peristrophe bicalyculata extract on Trypanosoma brucei brucei-infected rats

    Institute of Scientific and Technical Information of China (English)

    Abdulazeez Mansurah Abimbola; Ibrahim Abdulrazak Baba; Edibo Zakari Yenusa; Sidali Joseph Omanibe; Idris Habeeb Oladimeji


    Objective: To investigate the in vitro and in vivo effect of whole plant extracts of Peristrophe bicalyculata on Trypanosoma brucei brucei-infected rats. Methods: The experiment was divided into two phases: In the first phase, the anti-trypanosomal activity of the hot water, cold water, methanol and butanol extracts of the whole plant were determined by incubating with Trypanosoma brucei brucei. The cold water extract was partially-purified and the anti-trypanosomal activity of the fractions determined. In the second phase, Trypanosoma brucei brucei-infected rats were treated with fraction 2c for nine days. Packed cell volume (PCV), high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol (TC), triacylglycerol (TAG), aspartate aminotransferase, alanine aminotransferases (ALT), alkaline phosphatase (ALP), total and direct bilirubin levels were determined at the end of the experiment. Results:Cold water extract immobilized 90%of the parasites after 60 min of incubation, and fraction 2c completely immobilized the parasites after 35 min. It significantly increased PCV in Trypanosoma brucei brucei-infected rats. Decreased TC, TAG, HDL and LDL levels of infected rats increased significantly when rats were treated with the fraction, while elevated levels of total bilirubin and ALT also decreased. The difference in urea, direct bilirubin and ALP was not significant when infected rats were compared to rats in other groups. Conclusions:The ability of the plant to ameliorate the infection-induced biochemical changes calls for detailed investigation of the potentials of the plant for antitrypanosomiasis drug delivery.

  7. A Protein Complex Map of Trypanosoma brucei.

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    Vahid H Gazestani


    Full Text Available The functions of the majority of trypanosomatid-specific proteins are unknown, hindering our understanding of the biology and pathogenesis of Trypanosomatida. While protein-protein interactions are highly informative about protein function, a global map of protein interactions and complexes is still lacking for these important human parasites. Here, benefiting from in-depth biochemical fractionation, we systematically interrogated the co-complex interactions of more than 3354 protein groups in procyclic life stage of Trypanosoma brucei, the protozoan parasite responsible for human African trypanosomiasis. Using a rigorous methodology, our analysis led to identification of 128 high-confidence complexes encompassing 716 protein groups, including 635 protein groups that lacked experimental annotation. These complexes correlate well with known pathways as well as for proteins co-expressed across the T. brucei life cycle, and provide potential functions for a large number of previously uncharacterized proteins. We validated the functions of several novel proteins associated with the RNA-editing machinery, identifying a candidate potentially involved in the mitochondrial post-transcriptional regulation of T. brucei. Our data provide an unprecedented view of the protein complex map of T. brucei, and serve as a reliable resource for further characterization of trypanosomatid proteins. The presented results in this study are available at:

  8. Genetic control of resistance to Trypanosoma brucei brucei infection in mice.

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    Matyáš Síma


    Full Text Available BACKGROUND: Trypanosoma brucei brucei infects livestock, with severe effects in horses and dogs. Mouse strains differ greatly in susceptibility to this parasite. However, no genes controlling these differences were mapped. METHODS: We studied the genetic control of survival after T. b. brucei infection using recombinant congenic (RC strains, which have a high mapping power. Each RC strain of BALB/c-c-STS/A (CcS/Dem series contains a different random subset of 12.5% genes from the parental "donor" strain STS/A and 87.5% genes from the "background" strain BALB/c. Although BALB/c and STS/A mice are similarly susceptible to T. b. brucei, the RC strain CcS-11 is more susceptible than either of them. We analyzed genetics of survival in T. b. brucei-infected F(2 hybrids between BALB/c and CcS-11. CcS-11 strain carries STS-derived segments on eight chromosomes. They were genotyped in the F(2 hybrid mice and their linkage with survival was tested by analysis of variance. RESULTS: We mapped four Tbbr (Trypanosoma brucei brucei response loci that influence survival after T. b. brucei infection. Tbbr1 (chromosome 3 and Tbbr2 (chromosome 12 have effects on survival independent of inter-genic interactions (main effects. Tbbr3 (chromosome 7 influences survival in interaction with Tbbr4 (chromosome 19. Tbbr2 is located on a segment 2.15 Mb short that contains only 26 genes. CONCLUSION: This study presents the first identification of chromosomal loci controlling susceptibility to T. b. brucei infection. While mapping in F(2 hybrids of inbred strains usually has a precision of 40-80 Mb, in RC strains we mapped Tbbr2 to a 2.15 Mb segment containing only 26 genes, which will enable an effective search for the candidate gene. Definition of susceptibility genes will improve the understanding of pathways and genetic diversity underlying the disease and may result in new strategies to overcome the active subversion of the immune system by T. b. brucei.

  9. [Pseudo-tumoral human African trypanosomiasis due to Trypanosoma gambiense. Clinical and tomodensitometry study (author's transl)]. (United States)

    Poisson, M; Bleibel, J M; Regnier, A; Mashaly, R; Le Bigot, P; Danis, M; Buge, A

    The authors report an observation of african trypanosomiasis due to Trypanosoma Gambiense, clinical signs included massive and progressive hemiplegia, papillary edema and vascular shift from median line at arteriography. These pseudo tumoral clinical features are unusual in this disease. Asymetrical heterogenous hypodensities of the centrum semioval are dominant in the initial CT scanner aspect. The confrontation of CT scanner images to the clinical and evolutive data suggests the presence of associated cerebral edema and demyelination. With treatment, hypodensities were regressing while images of subcortical atrophy appeared. Lastly, in spite of severe general signs and the importance of neurological deficit, arsenical treatment associated with high doses of corticotherapy lead to a rapid improvement.

  10. Transport proteins determine drug sensitivity and resistance in a protozoan parasite, Trypanosoma brucei

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    Jane Claire Munday


    Full Text Available Drug resistance in pathogenic protozoa is very often caused by changes to the ‘transportome’ of the parasites. In Trypanosoma brucei, several transporters have been implicated in uptake of the main classes of drugs, diamidines and melaminophenyl arsenicals. The resistance mechanism had been thought to be due to loss of a transporter known to carry both types of agents: the aminopurine transporter P2, encoded by the gene TbAT1. However, although loss of P2 activity is well-documented as the cause of resistance to the veterinary diamidine diminazene aceturate (Berenil®, cross-resistance between the human-use arsenical melarsoprol and the diamidine pentamidine (MPXR is the result of loss of a separate High Affinity Pentamidine Transporter (HAPT1. A genome-wide RNAi library screen for resistance to pentamidine, published in 2012, gave the key to the genetic identity of HAPT1 by linking the phenomenon to a locus that contains the closely related T. brucei aquaglyceroporin genes TbAQP2 and TbAQP3. Further analysis determined that knockdown of only one pore, TbAQP2, produced the MPXR phenotype. TbAQP2 is an unconventional aquaglyceroporin with unique residues in the selectivity region of the pore, and it was found that in several MPXR lab strains the WT gene was either absent or replaced by a chimeric protein, recombined with parts of TbAQP3. Importantly, wild-type AQP2 was also absent in field isolates of T. b. gambiense, correlating with the outcome of melarsoprol treatment. Expression of a wild-type copy of TbAQP2 in even the most resistant strain completely reversed MPXR and re-introduced HAPT1 function and transport kinetics. Expression of TbAQP2 in Leishmania mexicana introduced a pentamidine transport activity indistinguishable from HAPT1. Although TbAQP2 has been shown to function as a classical aquaglyceroporin it is now clear that it is also a high affinity drug transporter, HAPT1. We discuss here a possible structural rationale for this

  11. Transport proteins determine drug sensitivity and resistance in a protozoan parasite, Trypanosoma brucei (United States)

    Munday, Jane C.; Settimo, Luca; de Koning, Harry P.


    Drug resistance in pathogenic protozoa is very often caused by changes to the ‘transportome’ of the parasites. In Trypanosoma brucei, several transporters have been implicated in uptake of the main classes of drugs, diamidines and melaminophenyl arsenicals. The resistance mechanism had been thought to be due to loss of a transporter known to carry both types of agents: the aminopurine transporter P2, encoded by the gene TbAT1. However, although loss of P2 activity is well-documented as the cause of resistance to the veterinary diamidine diminazene aceturate (DA; Berenil®), cross-resistance between the human-use arsenical melarsoprol and the diamidine pentamidine (melarsoprol/pentamidine cross resistance, MPXR) is the result of loss of a separate high affinity pentamidine transporter (HAPT1). A genome-wide RNAi library screen for resistance to pentamidine, published in 2012, gave the key to the genetic identity of HAPT1 by linking the phenomenon to a locus that contains the closely related T. brucei aquaglyceroporin genes TbAQP2 and TbAQP3. Further analysis determined that knockdown of only one pore, TbAQP2, produced the MPXR phenotype. TbAQP2 is an unconventional aquaglyceroporin with unique residues in the “selectivity region” of the pore, and it was found that in several MPXR lab strains the WT gene was either absent or replaced by a chimeric protein, recombined with parts of TbAQP3. Importantly, wild-type AQP2 was also absent in field isolates of T. b. gambiense, correlating with the outcome of melarsoprol treatment. Expression of a wild-type copy of TbAQP2 in even the most resistant strain completely reversed MPXR and re-introduced HAPT1 function and transport kinetics. Expression of TbAQP2 in Leishmania mexicana introduced a pentamidine transport activity indistinguishable from HAPT1. Although TbAQP2 has been shown to function as a classical aquaglyceroporin it is now clear that it is also a high affinity drug transporter, HAPT1. We discuss here a

  12. Identification and Characterization of FTY720 for the Treatment of Human African Trypanosomiasis (United States)

    Kaiser, Marcel; Avery, Vicky M.


    The screening of a focused library identified FTY720 (Fingolimod; Gilenya) as a potent selective antitrypanosomal compound active against Trypanosoma brucei gambiense and T. brucei rhodesiense, the causative agents of human African trypanosomiasis (HAT). This is the first report of trypanocidal activity for FTY720, an oral drug registered for the treatment of relapsing multiple sclerosis, and the characterization of sphingolipids as a potential new class of compounds for HAT. PMID:26666915

  13. Motility modes of the parasite Trypanosoma brucei (United States)

    Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth


    The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

  14. The transcriptome of the human pathogen Trypanosoma brucei at single-nucleotide resolution.

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    Nikolay G Kolev

    Full Text Available The genome of Trypanosoma brucei, the causative agent of African trypanosomiasis, was published five years ago, yet identification of all genes and their transcripts remains to be accomplished. Annotation is challenged by the organization of genes transcribed by RNA polymerase II (Pol II into long unidirectional gene clusters with no knowledge of how transcription is initiated. Here we report a single-nucleotide resolution genomic map of the T. brucei transcriptome, adding 1,114 new transcripts, including 103 non-coding RNAs, confirming and correcting many of the annotated features and revealing an extensive heterogeneity of 5' and 3' ends. Some of the new transcripts encode polypeptides that are either conserved in T. cruzi and Leishmania major or were previously detected in mass spectrometry analyses. High-throughput RNA sequencing (RNA-Seq was sensitive enough to detect transcripts at putative Pol II transcription initiation sites. Our results, as well as recent data from the literature, indicate that transcription initiation is not solely restricted to regions at the beginning of gene clusters, but may occur at internal sites. We also provide evidence that transcription at all putative initiation sites in T. brucei is bidirectional, a recently recognized fundamental property of eukaryotic promoters. Our results have implications for gene expression patterns in other important human pathogens with similar genome organization (Trypanosoma cruzi, Leishmania sp. and revealed heterogeneity in pre-mRNA processing that could potentially contribute to the survival and success of the parasite population in the insect vector and the mammalian host.

  15. Trypanosoma evansi is alike to Trypanosoma brucei brucei in the subcellular localisation of glycolytic enzymes

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    S Andrea Moreno


    Full Text Available Trypanosoma evansi, which causes surra, is descended from Trypanosoma brucei brucei, which causes nagana. Although both parasites are presumed to be metabolically similar, insufficient knowledge of T. evansi precludes a full comparison. Herein, we provide the first report on the subcellular localisation of the glycolytic enzymes in T. evansi, which is a alike to that of the bloodstream form (BSF of T. b. brucei: (i fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, hexokinase, phosphofructokinase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase (glycolytic enzymes and glycerol-3-phosphate dehydrogenase (a glycolysis-auxiliary enzyme in glycosomes, (ii enolase, phosphoglycerate mutase, pyruvate kinase (glycolytic enzymes and a GAPDH isoenzyme in the cytosol, (iii malate dehydrogenase in cytosol and (iv glucose-6-phosphate dehydrogenase in both glycosomes and the cytosol. Specific enzymatic activities also suggest that T. evansi is alike to the BSF of T. b. brucei in glycolytic flux, which is much faster than the pentose phosphate pathway flux, and in the involvement of cytosolic GAPDH in the NAD+/NADH balance. These similarities were expected based on the close phylogenetic relationship of both parasites.

  16. Trypanosoma evansi is alike to Trypanosoma brucei brucei in the subcellular localisation of glycolytic enzymes. (United States)

    Moreno, S Andrea; Nava, Mayerly


    Trypanosoma evansi, which causes surra, is descended from Trypanosoma brucei brucei, which causes nagana. Although both parasites are presumed to be metabolically similar, insufficient knowledge of T. evansi precludes a full comparison. Herein, we provide the first report on the subcellular localisation of the glycolytic enzymes in T. evansi, which is a alike to that of the bloodstream form (BSF) of T. b. brucei: (i) fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), hexokinase, phosphofructokinase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase (glycolytic enzymes) and glycerol-3-phosphate dehydrogenase (a glycolysis-auxiliary enzyme) in glycosomes, (ii) enolase, phosphoglycerate mutase, pyruvate kinase (glycolytic enzymes) and a GAPDH isoenzyme in the cytosol, (iii) malate dehydrogenase in cytosol and (iv) glucose-6-phosphate dehydrogenase in both glycosomes and the cytosol. Specific enzymatic activities also suggest that T. evansi is alike to the BSF of T. b. brucei in glycolytic flux, which is much faster than the pentose phosphate pathway flux, and in the involvement of cytosolic GAPDH in the NAD+/NADH balance. These similarities were expected based on the close phylogenetic relationship of both parasites.

  17. Cell-penetrating peptide TP10 shows broad-spectrum activity against both Plasmodium falciparum and Trypanosoma brucei brucei. (United States)

    Arrighi, Romanico B G; Ebikeme, Charles; Jiang, Yang; Ranford-Cartwright, Lisa; Barrett, Michael P; Langel, Ulo; Faye, Ingrid


    Malaria and trypanosomiasis are diseases which afflict millions and for which novel therapies are urgently required. We have tested two well-characterized cell-penetrating peptides (CPPs) for antiparasitic activity. One CPP, designated TP10, has broad-spectrum antiparasitic activity against Plasmodium falciparum, both blood and mosquito stages, and against blood-stage Trypanosoma brucei brucei.

  18. View of Causation for CSCW

    DEFF Research Database (Denmark)

    Christensen, Lars R.; Bertelsen, Olav W.


    In this chapter, we attempt to achieve a better understanding of how cooperative work is partly accomplished by virtue of the actors’ manipulation and control of causal relationships central to their material field of work. Previous CSCW studies have not focused extensively on causation in cooper......In this chapter, we attempt to achieve a better understanding of how cooperative work is partly accomplished by virtue of the actors’ manipulation and control of causal relationships central to their material field of work. Previous CSCW studies have not focused extensively on causation...

  19. Identifying transmission cycles at the human-animal interface: the role of animal reservoirs in maintaining gambiense human african trypanosomiasis.

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    Sebastian Funk

    Full Text Available Many infections can be transmitted between animals and humans. The epidemiological roles of different species can vary from important reservoirs to dead-end hosts. Here, we present a method to identify transmission cycles in different combinations of species from field data. We used this method to synthesise epidemiological and ecological data from Bipindi, Cameroon, a historical focus of gambiense Human African Trypanosomiasis (HAT, sleeping sickness, a disease that has often been considered to be maintained mainly by humans. We estimated the basic reproduction number [Formula: see text] of gambiense HAT in Bipindi and evaluated the potential for transmission in the absence of human cases. We found that under the assumption of random mixing between vectors and hosts, gambiense HAT could not be maintained in this focus without the contribution of animals. This result remains robust under extensive sensitivity analysis. When using the distributions of species among habitats to estimate the amount of mixing between those species, we found indications for an independent transmission cycle in wild animals. Stochastic simulation of the system confirmed that unless vectors moved between species very rarely, reintroduction would usually occur shortly after elimination of the infection from human populations. This suggests that elimination strategies may have to be reconsidered as targeting human cases alone would be insufficient for control, and reintroduction from animal reservoirs would remain a threat. Our approach is broadly applicable and could reveal animal reservoirs critical to the control of other infectious diseases.

  20. Synthetic biology and genetic causation. (United States)

    Oftedal, Gry; Parkkinen, Veli-Pekka


    Synthetic biology research is often described in terms of programming cells through the introduction of synthetic genes. Genetic material is seemingly attributed with a high level of causal responsibility. We discuss genetic causation in synthetic biology and distinguish three gene concepts differing in their assumptions of genetic control. We argue that synthetic biology generally employs a difference-making approach to establishing genetic causes, and that this approach does not commit to a specific notion of genetic program or genetic control. Still, we suggest that a strong program concept of genetic material can be used as a successful heuristic in certain areas of synthetic biology. Its application requires control of causal context, and may stand in need of a modular decomposition of the target system. We relate different modularity concepts to the discussion of genetic causation and point to possible advantages of and important limitations to seeking modularity in synthetic biology systems.


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    Georges C. Accrombessi


    Full Text Available The structure of four synthesized thiosemicarbazones, substituted or not, of benzophenone has been confirmed by spectrometrical analysis IR, NMR 1H and 13C. Their anti-trypanosomal activities were evaluated on Trypanosoma brucei brucei. Among these compounds, benzophenone 4 phenyl-3-thiosemicarbazone 4 has the highest activity with the half-inhibitory concentration (IC50 = 8.48 micromolar (µM. Benzophenone 4-methyl-3-thiosemicarbazone 3 and benzophenone thiosemicarbazone 1 showed moderate anti-trypanosomal activity with IC50 values equal to 23.27 µM and 67.17 µM respectively. Benzophenone 2 methyl-3-thiosemicarbazone 2 showed no activity up to IC50 = 371.74 µM.

  2. Proline Metabolism is Essential for Trypanosoma brucei brucei Survival in the Tsetse Vector (United States)

    Mantilla, Brian S.; Dyer, Naomi A.; Biran, Marc; Bringaud, Frédéric; Lehane, Michael J.; Acosta-Serrano, Alvaro


    Adaptation to different nutritional environments is essential for life cycle completion by all Trypanosoma brucei sub-species. In the tsetse fly vector, L-proline is among the most abundant amino acids and is mainly used by the fly for lactation and to fuel flight muscle. The procyclic (insect) stage of T. b. brucei uses L-proline as its main carbon source, relying on an efficient catabolic pathway to convert it to glutamate, and then to succinate, acetate and alanine as the main secreted end products. Here we investigated the essentiality of an undisrupted proline catabolic pathway in T. b. brucei by studying mitochondrial Δ1-pyrroline-5-carboxylate dehydrogenase (TbP5CDH), which catalyzes the irreversible conversion of gamma-glutamate semialdehyde (γGS) into L-glutamate and NADH. In addition, we provided evidence for the absence of a functional proline biosynthetic pathway. TbP5CDH expression is developmentally regulated in the insect stages of the parasite, but absent in bloodstream forms grown in vitro. RNAi down-regulation of TbP5CDH severely affected the growth of procyclic trypanosomes in vitro in the absence of glucose, and altered the metabolic flux when proline was the sole carbon source. Furthermore, TbP5CDH knocked-down cells exhibited alterations in the mitochondrial inner membrane potential (ΔΨm), respiratory control ratio and ATP production. Also, changes in the proline-glutamate oxidative capacity slightly affected the surface expression of the major surface glycoprotein EP-procyclin. In the tsetse, TbP5CDH knocked-down cells were impaired and thus unable to colonize the fly’s midgut, probably due to the lack of glucose between bloodmeals. Altogether, our data show that the regulated expression of the proline metabolism pathway in T. b. brucei allows this parasite to adapt to the nutritional environment of the tsetse midgut. PMID:28114403

  3. Classical clinical signs in rats experimemtally infected with Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omolathebu


    Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats. Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats. Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei. Results:Parasitaemia was recorded in Group B by (3.86±0.34) d and the peak of parasitaemia was observed at Day 5 post infection. Classical signs observed included squint eyes, raised whiskers, lethargy, no weight loss, pyrexia, isolation from the other rats, and starry hair coat. Conclusions:These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.

  4. Organic causation of morbid jealousy. (United States)

    Kuruppuarachchi, K A L A; Seneviratne, A N


    This article describes the organic contribution to morbid jealousy. Although the true prevalence of morbid jealousy is unknown, organic factors contribute significantly to its development. We present an assortment of five case histories to highlight the importance of organic causation in this phenomenon. The first two cases portray organic delusional disorder arising as an aftermath of cerebral infarcts. They are both associated with left sided brain lesions. Though organic processes generally respond poorly to treatment, case 3 (patient with head injury), is unusual as it describes a young man whose symptoms resolve on recovering from the effects of a head injury. Likewise, case 4 (patient with a meningioma) who made a complete recovery following surgery, emphasizes the need for early detection of reversible causes. The difficulty in identifying the common substrate for a phenomenon with such a wide variety of causations is amply displayed by the abundance of theories forwarded. The blurred demarcation between normal jealousy and pathological jealousy leads to further uncertainty. The excess representation of morbid jealousy in organic conditions is not enlightened by these theories. Organic pathology, by affecting the higher centers of the brain, may remove the control over instinctual behaviour. Evidence for this is hard to establish but the evolutionary perspective of jealousy akin to that of the animal kingdom alludes to possible explanations.

  5. Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei

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    Ya Nan Sun


    Full Text Available Neglected tropical diseases (NTDs affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness, caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds—4, 7, 11, 14, 15, 18, 20, and 21—showed inhibitory activity against T. brucei, with IC50 values below 5 µM, ranging from 0.52 to 4.70 μM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT.

  6. Regulation and spatial organization of PCNA in Trypanosoma brucei

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    Kaufmann, Doris; Gassen, Alwine [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Maiser, Andreas; Leonhardt, Heinrich [University of Munich (LMU), Department Biology II, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Janzen, Christian J., E-mail: [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany)


    Highlights: Black-Right-Pointing-Pointer Characterization of the proliferating cell nuclear antigen in Trypanosoma brucei (TbPCNA). Black-Right-Pointing-Pointer TbPCNA is a suitable marker to detect replication in T. brucei. Black-Right-Pointing-Pointer TbPCNA distribution and regulation is different compared to closely related parasites T. cruzi and Leishmania donovani. -- Abstract: As in most eukaryotic cells, replication is regulated by a conserved group of proteins in the early-diverged parasite Trypanosoma brucei. Only a few components of the replication machinery have been described in this parasite and regulation, sub-nuclear localization and timing of replication are not well understood. We characterized the proliferating cell nuclear antigen in T. brucei (TbPCNA) to establish a spatial and temporal marker for replication. Interestingly, PCNA distribution and regulation is different compared to the closely related parasites Trypanosoma cruzi and Leishmania donovani. TbPCNA foci are clearly detectable during S phase of the cell cycle but in contrast to T. cruzi they are not preferentially located at the nuclear periphery. Furthermore, PCNA seems to be degraded when cells enter G2 phase in T. brucei suggesting different modes of replication regulation or functions of PCNA in these closely related eukaryotes.

  7. Effect of ivermectin on Trypanosoma brucei brucei in experimentally infected mice

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    Udensi K. Udensi & A.F. Fagbenro-Beyioku


    Full Text Available Background & objectives: Human and livestock African trypanosomiasis, otherwise known as sleeping sickness,is a neglected tropical disease of public health importance in west and central Africa. In view of the adverse sideeffects of the antitrypanosomal drugs, the relatively few side effects observed in ivermectin use, and becauseboth onchocerciasis and typanosomiasis occur in overlapping foci in Africa, it would be desirable if the ivermectinthat has been used successfully on onchocerciasis management could also be used in the control and treatmentof trypanosomiasis.Method: In this study, prophylactic and therapeutic effects of ivermectin (Mectizan were investigated in albinomice infected with a Nigerian strain of Trypanosoma brucei brucei.Results: A 300 μg/ml/kg dose had the most effective impact because it showed the highest mean survival time of12 days in both the treatment and prophylactic groups of mice. This dose also enhanced the defence capacity ofthe treated groups. It also had positive influence on the packed cell volume (PCV and the state of anaemia inthe trypanosome infected mice, hence, improving their survivability.Interpretation & conclusions: Our report indicates that using the 300 μg/ml/kg dose of ivermectin increases themean survival period from 5 to 12 days. This suggests that ivermectin could be possibly used in the treatment oftrypanosomiasis. Further studies will be required to show whether proper treatment may entail a single dose, asused in this study; an increased number of doses, or combinations with other drugs.

  8. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi

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    Nathan Habila


    Full Text Available Essential oils (EOs from Cymbopogon citratus (CC, Eucalyptus citriodora (EC, Eucalyptus camaldulensis (ED, and Citrus sinensis (CS were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb and Trypanosoma evansi (T. evansi. The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09% in CS, 6-octenal (77.11% in EC, Eucalyptol (75% in ED, and Citral (38.32% in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy.

  9. Crystal structures of Trypanosoma brucei oligopeptidase B broaden the paradigm of catalytic regulation in prolyl oligopeptidase family enzymes. (United States)

    Canning, Peter; Rea, Dean; Morty, Rory E; Fülöp, Vilmos


    Oligopeptidase B cleaves after basic amino acids in peptides up to 30 residues. As a virulence factor in bacteria and trypanosomatid pathogens that is absent in higher eukaryotes, this is a promising drug target. Here we present ligand-free open state and inhibitor-bound closed state crystal structures of oligopeptidase B from Trypanosoma brucei, the causative agent of African sleeping sickness. These (and related) structures show the importance of structural dynamics, governed by a fine enthalpic and entropic balance, in substrate size selectivity and catalysis. Peptides over 30 residues cannot fit the enzyme cavity, preventing the complete domain closure required for a key propeller Asp/Glu to fix the catalytic His and Arg in the catalytically competent conformation. This size exclusion mechanism protects larger peptides and proteins from degradation. Similar bacterial prolyl endopeptidase and archael acylaminoacyl peptidase structures demonstrate this mechanism is conserved among oligopeptidase family enzymes across all three domains of life.

  10. Crystal structures of Trypanosoma brucei oligopeptidase B broaden the paradigm of catalytic regulation in prolyl oligopeptidase family enzymes.

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    Peter Canning

    Full Text Available Oligopeptidase B cleaves after basic amino acids in peptides up to 30 residues. As a virulence factor in bacteria and trypanosomatid pathogens that is absent in higher eukaryotes, this is a promising drug target. Here we present ligand-free open state and inhibitor-bound closed state crystal structures of oligopeptidase B from Trypanosoma brucei, the causative agent of African sleeping sickness. These (and related structures show the importance of structural dynamics, governed by a fine enthalpic and entropic balance, in substrate size selectivity and catalysis. Peptides over 30 residues cannot fit the enzyme cavity, preventing the complete domain closure required for a key propeller Asp/Glu to fix the catalytic His and Arg in the catalytically competent conformation. This size exclusion mechanism protects larger peptides and proteins from degradation. Similar bacterial prolyl endopeptidase and archael acylaminoacyl peptidase structures demonstrate this mechanism is conserved among oligopeptidase family enzymes across all three domains of life.

  11. Nanomolar Inhibitors of Trypanosoma brucei RNA Triphosphatase

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    Paul Smith


    Full Text Available Eukaryal taxa differ with respect to the structure and mechanism of the RNA triphosphatase (RTPase component of the mRNA capping apparatus. Protozoa, fungi, and certain DNA viruses have a metal-dependent RTPase that belongs to the triphosphate tunnel metalloenzyme (TTM superfamily. Because the structures, active sites, and chemical mechanisms of the TTM-type RTPases differ from those of mammalian RTPases, the TTM RTPases are potential targets for antiprotozoal, antifungal, and antiviral drug discovery. Here, we employed RNA interference (RNAi knockdown methods to show that Trypanosoma brucei RTPase Cet1 (TbCet1 is necessary for proliferation of procyclic cells in culture. We then conducted a high-throughput biochemical screen for small-molecule inhibitors of the phosphohydrolase activity of TbCet1. We identified several classes of chemicals—including chlorogenic acids, phenolic glycopyranosides, flavonoids, and other phenolics—that inhibit TbCet1 with nanomolar to low-micromolar 50% inhibitory concentrations (IC50s. We confirmed the activity of these compounds, and tested various analogs thereof, by direct manual assays of TbCet1 phosphohydrolase activity. The most potent nanomolar inhibitors included tetracaffeoylquinic acid, 5-galloylgalloylquinic acid, pentagalloylglucose, rosmarinic acid, and miquelianin. TbCet1 inhibitors were less active (or inactive against the orthologous TTM-type RTPases of mimivirus, baculovirus, and budding yeast (Saccharomyces cerevisiae. Our results affirm that a TTM RTPase is subject to potent inhibition by small molecules, with the caveat that parallel screens against TTM RTPases from multiple different pathogens may be required to fully probe the chemical space of TTM inhibition.

  12. A tropical tale: how Naja nigricollis venom beats Trypanosoma brucei

    DEFF Research Database (Denmark)

    Martos Esteban, Andrea; Laustsen, Andreas Hougaard; Carrington, Mark

    Trypanosoma brucei is a parasitic protozoan species capable to infecting insect vectors whose bite further produces African sleeping sickness inhuman beings [1]. During the parasite’s extracellular life in the mammalian host,its outer coat, mainly composed of Variable Surface Glycoproteins (VSGs...

  13. In vitro antitrypanosomal activity of plant terpenes against Trypanosoma brucei. (United States)

    Otoguro, Kazuhiko; Iwatsuki, Masato; Ishiyama, Aki; Namatame, Miyuki; Nishihara-Tukashima, Aki; Kiyohara, Hiroaki; Hashimoto, Toshihiro; Asakawa, Yoshinori; Omura, Satoshi; Yamada, Haruki


    During the course of screening to discover antitrypanosomal compounds, 24 known plant terpenes (6 sesquiterpenes, 14 sesquiterpene lactones and 4 diterpenes) were evaluated for in vitro antitrypanosomal activity against Trypanosoma brucei brucei. Among them, 22 terpenes exhibited antitrypanosomal activity. In particular, α-eudesmol, hinesol, nardosinone and 4-peroxy-1,2,4,5-tetrahydro-α-santonin all exhibited selective and potent antitrypanosomal activities in vitro. Detailed here in an in vitro antitrypanosomal properties and cytotoxicities of the 24 terpenes compared with two therapeutic antitrypanosomal drugs (eflornithine and suramin). This finding represents the first report of promising trypanocidal activity of these terpenes. Present results also provide some valuable insight with regard to structure-activity relationships and the possible mode of action of the compounds.

  14. Iconicity of cohesion in Persian causative constructions

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    Mohammad Ali Salmani Nodoushan


    Full Text Available This paper tries to show that Persian causative constructions are not only iconic in nature but also employ iconicity of cohesion in their syntactic structures productively. It starts with a description of iconicity and specifically focuses on the notion of conceptual distance as discussed by Haiman (1983. It then briefly reviews the formal typology of causative constructions (i. e., lexical, morphological, and periphrastic and summarizes the ideas proposed by Comrie (1989, Dixon (2000, Shibatani (1976, and Talmy (2003 to come up with a list of, and a table for, the semantic properties of causative constructions (i. e., directness, coercion, control, manipulation, separability, and clause structure. The paper then presents tangible evidence and examples from Persian to claim that the linguistic distance observed between [Vcause] and [Veffect] in different types of Persian causative constructions mirrors the conceptual distance between them, and concludes that the iconic nature of causative constructions in Persian can be explained on the basis of the principle of iconicity of cohesion. It lends support to the universality of the principles of functional-cognitive linguistics and shows that iconicity theory still has a high potential for explaining form-meaning relations in different syntactic structures.

  15. Single molecule analysis of Trypanosoma brucei DNA replication dynamics. (United States)

    Calderano, Simone Guedes; Drosopoulos, William C; Quaresma, Marina Mônaco; Marques, Catarina A; Kosiyatrakul, Settapong; McCulloch, Richard; Schildkraut, Carl L; Elias, Maria Carolina


    Eukaryotic genome duplication relies on origins of replication, distributed over multiple chromosomes, to initiate DNA replication. A recent genome-wide analysis of Trypanosoma brucei, the etiological agent of sleeping sickness, localized its replication origins to the boundaries of multigenic transcription units. To better understand genomic replication in this organism, we examined replication by single molecule analysis of replicated DNA. We determined the average speed of replication forks of procyclic and bloodstream form cells and we found that T. brucei DNA replication rate is similar to rates seen in other eukaryotes. We also analyzed the replication dynamics of a central region of chromosome 1 in procyclic forms. We present evidence for replication terminating within the central part of the chromosome and thus emanating from both sides, suggesting a previously unmapped origin toward the 5' extremity of chromosome 1. Also, termination is not at a fixed location in chromosome 1, but is rather variable. Importantly, we found a replication origin located near an ORC1/CDC6 binding site that is detected after replicative stress induced by hydroxyurea treatment, suggesting it may be a dormant origin activated in response to replicative stress. Collectively, our findings support the existence of more replication origins in T. brucei than previously appreciated.

  16. Trypanosoma brucei mitochondrial respiratome: Composition and organization in procyclic form

    KAUST Repository

    Acestor, Nathalie


    The mitochondrial respiratory chain is comprised of four different protein complexes (I-IV), which are responsible for electron transport and generation of proton gradient in the mitochondrial intermembrane space. This proton gradient is then used by F oF 1-ATP synthase (complex V) to produce ATP by oxidative phosphorylation. In this study, the respiratory complexes I, II, and III were affinity purified from Trypanosoma brucei procyclic form cells and their composition was determined by mass spectrometry. The results along with those that we previously reported for complexes IV and V showed that the respiratome of Trypanosoma is divergent because many of its proteins are unique to this group of organisms. The studies also identified two mitochondrial subunit proteins of respiratory complex IV that are encoded by edited RNAs. Proteomics data from analyses of complexes purified using numerous tagged component proteins in each of the five complexes were used to generate the first predicted protein-protein interaction network of the Trypanosoma brucei respiratory chain. These results provide the first comprehensive insight into the unique composition of the respiratory complexes in Trypanosoma brucei, an early diverged eukaryotic pathogen. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Laws, Causation and Dynamics at Different Levels

    CERN Document Server

    Butterfield, Jeremy


    I have two main aims. The first is general, and more philosophical (Section 2). The second is specific, and more closely related to physics (Sections 3 and 4). The first aim is to state my general views about laws and causation at different 'levels'. The main task is to understand how the higher levels sustain notions of law and causation that 'ride free' of reductions to the lower level or levels. I endeavour to relate my views to those of other symposiasts. The second aim is to give a framework for describing dynamics at different levels, emphasising how the various levels' dynamics can mesh or fail to mesh. This framework is essentially that of elementary dynamical systems theory. The main idea will be, for simplicity, to work with just two levels, dubbed 'micro' and 'macro' which are related by coarse-graining. I use this framework to describe, in part, the first four of Ellis' five types of top-down causation.

  18. Intraclonal mating occurs during tsetse transmission of Trypanosoma brucei

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    Ferris Vanessa


    Full Text Available Abstract Background Mating in Trypanosoma brucei is a non-obligatory event, triggered by the co-occurrence of different strains in the salivary glands of the vector. Recombinants that result from intra- rather than interclonal mating have been detected, but only in crosses of two different trypanosome strains. This has led to the hypothesis that when trypanosomes recognize a different strain, they release a diffusible factor or pheromone that triggers mating in any cell in the vicinity whether it is of the same or a different strain. This idea assumes that the trypanosome can recognize self and non-self, although there is as yet no evidence for the existence of mating types in T. brucei. Results We investigated intraclonal mating in T. b. brucei by crossing red and green fluorescent lines of a single strain, so that recombinant progeny can be detected in the fly by yellow fluorescence. For strain 1738, seven flies had both red and green trypanosomes in the salivary glands and, in three, yellow trypanosomes were also observed, although they could not be recovered for subsequent analysis. Nonetheless, both red and non-fluorescent clones from these flies had recombinant genotypes as judged by microsatellite and karyotype analyses, and some also had raised DNA contents, suggesting recombination or genome duplication. Strain J10 produced similar results indicative of intraclonal mating. In contrast, trypanosome clones recovered from other flies showed that genotypes can be transmitted with fidelity. When a yellow hybrid clone expressing both red and green fluorescent protein genes was transmitted, the salivary glands contained a mixture of fluorescent-coloured trypanosomes, but only yellow and red clones were recovered. While loss of the GFP gene in the red clones could have resulted from gene conversion, some of these clones showed loss of heterozygosity and raised DNA contents as in the other single strain transmissions. Our observations suggest

  19. Febrile Seizure: Demographic Features and Causative Factors



    How to cite this article: Esmaili Gourabi H, Bidabadi E, Cheraghalipour  F, Aarabi  Y, Salamat F. Febrile Seizure: Demographic Features and Causative Factors. Iran J Child Neurol Autumn 2012; 6(4):33-37.Abstract Objective Because of geographical and periodical variation, we prompted to determine the demographic features and causative factors for febrile seizure in Rasht. Materials & Methods In this cross-sectional study, all 6–month- to 6-year-old children with the diagnosis of febrile s...

  20. Mathematical modelling of polyamine metabolism in bloodstream-form Trypanosoma brucei: an application to drug target identification.

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    Xu Gu

    Full Text Available We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT and ornithine production (OrnPt have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.

  1. Structural characterization of CYP51 from Trypanosoma cruzi and Trypanosoma brucei bound to the antifungal drugs posaconazole and fluconazole.

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    Chiung-Kuang Chen

    Full Text Available BACKGROUND: Chagas Disease is the leading cause of heart failure in Latin America. Current drug therapy is limited by issues of both efficacy and severe side effects. Trypansoma cruzi, the protozoan agent of Chagas Disease, is closely related to two other major global pathogens, Leishmania spp., responsible for leishmaniasis, and Trypansoma brucei, the causative agent of African Sleeping Sickness. Both T. cruzi and Leishmania parasites have an essential requirement for ergosterol, and are thus vulnerable to inhibitors of sterol 14alpha-demethylase (CYP51, which catalyzes the conversion of lanosterol to ergosterol. Clinically employed anti-fungal azoles inhibit ergosterol biosynthesis in fungi, and specific azoles are also effective against both Trypanosoma and Leishmania parasites. However, modification of azoles to enhance efficacy and circumvent potential drug resistance has been problematic for both parasitic and fungal infections due to the lack of structural insights into drug binding. METHODOLOGY/PRINCIPAL FINDINGS: We have determined the crystal structures for CYP51 from T. cruzi (resolutions of 2.35 A and 2.27 A, and from the related pathogen T. brucei (resolutions of 2.7 A and 2.6 A, co-crystallized with the antifungal drugs fluconazole and posaconazole. Remarkably, both drugs adopt multiple conformations when binding the target. The fluconazole 2,4-difluorophenyl ring flips 180 degrees depending on the H-bonding interactions with the BC-loop. The terminus of the long functional tail group of posaconazole is bound loosely in the mouth of the hydrophobic substrate binding tunnel, suggesting that the major contribution of the tail to drug efficacy is for pharmacokinetics rather than in interactions with the target. CONCLUSIONS/SIGNIFICANCE: The structures provide new insights into binding of azoles to CYP51 and mechanisms of potential drug resistance. Our studies define in structural detail the CYP51 therapeutic target in T. cruzi, and

  2. In Vitro Trypanocidal Activity of Antibodies to Bacterially Ex­pressed Trypanosoma brucei Tubulin

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    GW Lubega


    Full Text Available Background: There are only four drugs for treating African trypanosomiasis, a devastating disease in sub-Saharan Africa. With slow discovery of better drugs, vaccination is viewed as the best method of control. We previously showed that antibodies to native Trypanosoma brucei brucei tubulin inhibit the growth of trypanosomes in culture. Here, we aimed to determine the effect of antibodies to bacte­rially expressed trypanosome tubulin on T. brucei brucei growth. Methods: T. brucei brucei alpha and beta tubulin genes were individually expressed in Escherichia coli under the tryptophan promoter. Monoclonal tubulin antibodies reacted specifically with the ex­pressed tubulins with no cross-reaction with the opposite tubulin. Rabbits were immunized with 450μg each of the concentrated recombinant tubulin, and production of antibodies assessed by ELISA and Western blotting. The effect of polyclonal antibodies on trypanosome growth was deter­mined by culturing bloodstream T. brucei brucei in up to 25% of antisera. Results: Low antisera dilutions (25% from the immunized rabbits inhibited trypanosome growth. The most cytotoxic antisera were from one rabbit immunized with a mixture of both alpha and beta tubulins. However, the result was not reproduced in other rabbits and there was no apparent effect on growth at higher antisera dilutions. Conclusion: Antibodies to bacterially expressed trypanosome tubulin are not effective at killing cul­tured bloodstream trypanosomes.

  3. [Causation, prevention and treatment of dust explosion]. (United States)

    Dong, Maolong; Jia, Wenbin; Wang, Hongtao; Han, Fei; Li, Xiao-Qiang; Hu, Dahai


    With the development of industrial technology, dust explosion accidents have increased, causing serious losses of people's lives and property. With the development of economy, we should lay further emphasis on causation, prevention, and treatment of dust explosion. This article summarizes the background, mechanism, prevention, and treatment of dust explosion, which may provide some professional knowledge and reference for the treatment of dust explosion.

  4. Biosynthesis and uptake of thiamine (vitamin B1) in bloodstream form Trypanosoma brucei brucei and interference of the vitamin with melarsen oxide activity. (United States)

    Stoffel, Sabine A; Rodenko, Boris; Schweingruber, Anne-Marie; Mäser, Pascal; de Koning, Harry P; Schweingruber, M Ernst


    Bloodstream forms of Trypanosoma brucei brucei were cultivated in the presence and absence of thiamine (vitamin B1) and pyridoxine (vitamin B6). The vitamins do not change growth behaviour, indicating that Trypanosoma brucei is prototrophic for the two vitamins even though in silico no bona-fide thiamine-biosynthetic genes could be identified in the T. brucei genome. Intracellularly, thiamine is mainly present in its diphosphate form. We were unable to detect significant uptake of [3H]thiamine and structural thiamine analogues such as pyrithiamine, oxithiamine and amprolium were not toxic for the bloodstream forms of T. brucei, indicating that the organism does not have an efficient uptake system for thiamine and its analogues. We have previously shown that, in the fission yeast Saccharomyces pombe, the toxicity of melarsen oxide, the pharmacologically active derivative of the frontline sleeping sickness drug melarsoprol, is abolished by thiamine and the drug is taken up by a thiamine-regulated membrane protein which is responsible for the utilization of thiamine. We show here that thiamine also has weak effects on melarsen oxide-induced growth inhibition and lysis in T. brucei. These effects were consistent with a low affinity of thiamine for the P2 adenosine transporter that is responsible for uptake of melaminophenyl arsenicals in African trypanosomes.

  5. Rab23 is a flagellar protein in Trypanosoma brucei

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    Field Mark C


    Full Text Available Abstract Background Rab small GTPases are important mediators of membrane transport, and orthologues frequently retain similar locations and functions, even between highly divergent taxa. In metazoan organisms Rab23 is an important negative regulator of Sonic hedgehog signaling and is crucial for correct development and differentiation of cellular lineages by virtue of an involvement in ciliary recycling. Previously, we reported that Trypanosoma brucei Rab23 localized to the nuclear envelope 1, which is clearly inconsistent with the mammalian location and function. As T. brucei is unicellular the potential that Rab23 has no role in cell signaling was possible. Here we sought to further investigate the role(s of Rab23 in T. brucei to determine if Rab23 was an example of a Rab protein with divergent function in distinct taxa. Methods/major findings The taxonomic distribution of Rab23 was examined and compared with the presence of flagella/cilia in representative taxa. Despite evidence for considerable secondary loss, we found a clear correlation between a conventional flagellar structure and the presence of a Rab23 orthologue in the genome. By epitope-tagging, Rab23 was localized and found to be present at the flagellum throughout the cell cycle. However, RNAi knockdown did not result in a flagellar defect, suggesting that Rab23 is not required for construction or maintenance of the flagellum. Conclusions The location of Rab23 at the flagellum is conserved between mammals and trypanosomes and the Rab23 gene is restricted to flagellated organisms. These data may suggest the presence of a Rab23-mediated signaling mechanism in trypanosomes.

  6. Selective inhibition of 6-phosphogluconate dehydrogenase from Trypanosoma brucei (United States)

    Bertelli, Massimo; El-Bastawissy, Eman; Knaggs, Michael H.; Barrett, Michael P.; Hanau, Stefania; Gilbert, Ian H.


    A number of triphenylmethane derivatives have been screened against 6-phosphogluconate dehydrogenase from Trypanosoma brucei and sheep liver. Some of these compounds show good inhibition of the enzymes and also selectivity towards the parasite enzyme. Modelling was undertaken to dock the compounds into the active sites of both enzymes. Using a combination of DOCK 3.5 and FLEXIDOCK a correlation was obtained between docking score and both activity for the enzymes and selectivity. Visualisation of the docked structures of the inhibitors in the active sites of the enzymes yielded a possible explanation of the selectivity for the parasite enzyme.

  7. Minimum Information Loss Based Multi-kernel Learning for Flagellar Protein Recognition in Trypanosoma Brucei

    KAUST Repository

    Wang, Jim Jing-Yan


    Trypanosma brucei (T. Brucei) is an important pathogen agent of African trypanosomiasis. The flagellum is an essential and multifunctional organelle of T. Brucei, thus it is very important to recognize the flagellar proteins from T. Brucei proteins for the purposes of both biological research and drug design. In this paper, we investigate computationally recognizing flagellar proteins in T. Brucei by pattern recognition methods. It is argued that an optimal decision function can be obtained as the difference of probability functions of flagella protein and the non-flagellar protein for the purpose of flagella protein recognition. We propose to learn a multi-kernel classification function to approximate this optimal decision function, by minimizing the information loss of such approximation which is measured by the Kull back-Leibler (KL) divergence. An iterative multi-kernel classifier learning algorithm is developed to minimize the KL divergence for the problem of T. Brucei flagella protein recognition, experiments show its advantage over other T. Brucei flagellar protein recognition and multi-kernel learning methods. © 2014 IEEE.

  8. Telomeric expression sites are highly conserved in Trypanosoma brucei.

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    Christiane Hertz-Fowler

    Full Text Available Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs. The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology.

  9. Combinations of alkaloids affecting different molecular targets with the saponin digitonin can synergistically enhance trypanocidal activity against Trypanosoma brucei brucei. (United States)

    Krstin, Sonja; Peixoto, Herbenya Silva; Wink, Michael


    The flagellate Trypanosoma brucei causes sleeping sickness in humans and nagana in animals. Only a few drugs are registered to treat trypanosomiasis, but those drugs show severe side effects. Also, because some pathogen strains have become resistant, new strategies are urgently needed to combat this parasitic disease. An underexplored possibility is the application of combinations of several trypanocidal agents, which may potentiate their trypanocidal activity in a synergistic fashion. In this study, the potential synergism of mutual combinations of bioactive alkaloids and alkaloids with a membrane-active steroidal saponin, digitonin, was explored with regard to their effect on T. b. brucei. Alkaloids were selected that affect different molecular targets: berberine and chelerythrine (intercalation of DNA), piperine (induction of apoptosis), vinblastine (inhibition of microtubule assembly), emetine (intercalation of DNA, inhibition of protein biosynthesis), homoharringtonine (inhibition of protein biosynthesis), and digitonin (membrane permeabilization and uptake facilitation of polar compounds). Most combinations resulted in an enhanced trypanocidal effect. The addition of digitonin significantly stimulated the activity of almost all alkaloids against trypanosomes. The strongest effect was measured in a combination of digitonin with vinblastine. The highest dose reduction indexes (DRI) were measured in the two-drug combination of digitonin or piperine with vinblastine, where the dose of vinblastine could be reduced 9.07-fold or 7.05-fold, respectively. The synergistic effects of mutual combinations of alkaloids and of alkaloids with digitonin present a new avenue to treat trypanosomiasis but one which needs to be corroborated in future animal experiments.

  10. Antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger on Trypanosoma brucei brucei-infected Wistar mice

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    P. I. Kobo


    Full Text Available Aim: The study was carried out to determine the in vivo antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger in Trypanosoma brucei brucei-infected mice. Materials and Methods: Twenty-five mice were randomly allocated into five groups of five animals each. Group I and II were given Tween 80 (1 ml/kg and diminazene aceturate (3.5 mg/kg to serve as untreated and treated controls, respectively. Groups III-V received the extract at 200, 400 and 800 mg/kg body weight, respectively. All treatments were given for 6 consecutive days and through the oral route. The mean body weight, mean survival period and daily level of parasitaemia were evaluated. Results: Acute toxicity showed the extract to be relatively safe. There was an insignificant increase in body weight and survival rate of mice treated with the extract. The level of parasitaemia in the extract treated groups was decreased. Conclusion: This study shows the in vivo potential of methanolic extract of Z. officinale in the treatment of trypanosomiasis.

  11. Causation and Responsibility: A New Direction

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    Matt Mortellaro


    Full Text Available In “Property, Causality, and Liability” and “Causation and Aggression,” Hans-Hermann Hoppe and Stephan Kinsella & Patrick Tinsley, respectively, argue against the Rothbardian position on criminal liability, especially with regard to the issue of incitement. This essay takes a critical look at the suggested approaches of both and attempts to defend the Rothbardian position on incitement from their criticisms. Further, this essay examines the views of Walter Block on incitement and attempts to correct inconsistencies in his position with regard to murder contracts and threats.

  12. Cofactor-independent phosphoglycerate mutase is an essential gene in procyclic form Trypanosoma brucei. (United States)

    Djikeng, Appolinaire; Raverdy, Sylvine; Foster, Jeremy; Bartholomeu, Daniella; Zhang, Yinhua; El-Sayed, Najib M; Carlow, Clotilde


    Glycolysis and gluconeogenesis are, in part, driven by the interconversion of 3- and 2-phosphoglycerate (3-PG and 2-PG) which is performed by phosphoglycerate mutases (PGAMs) which can be cofactor dependant (dPGAM) or cofactor independent (iPGAM). The African trypanosome, Trypanosoma brucei, possesses the iPGAM form which is thought to play an important role in glycolysis. Here, we report on the use of RNA interference to down-regulate the T. brucei iPGAM in procyclic form T. brucei and evaluation of the resulting phenotype. We first demonstrated biochemically that depletion of the steady state levels of iPGM mRNA correlates with a marked reduction of enzyme activity. We further show that iPGAM is required for cell growth in procyclic T. brucei.

  13. Mosaic VSGs and the scale of Trypanosoma brucei antigenic variation.

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    James P J Hall

    Full Text Available A main determinant of prolonged Trypanosoma brucei infection and transmission and success of the parasite is the interplay between host acquired immunity and antigenic variation of the parasite variant surface glycoprotein (VSG coat. About 0.1% of trypanosome divisions produce a switch to a different VSG through differential expression of an archive of hundreds of silent VSG genes and pseudogenes, but the patterns and extent of the trypanosome diversity phenotype, particularly in chronic infection, are unclear. We applied longitudinal VSG cDNA sequencing to estimate variant richness and test whether pseudogenes contribute to antigenic variation. We show that individual growth peaks can contain at least 15 distinct variants, are estimated computationally to comprise many more, and that antigenically distinct 'mosaic' VSGs arise from segmental gene conversion between donor VSG genes or pseudogenes. The potential for trypanosome antigenic variation is probably much greater than VSG archive size; mosaic VSGs are core to antigenic variation and chronic infection.

  14. Pathogenesis of anemia in Trypanosoma brucei-infected mice. (United States)

    Amole, B O; Clarkson, A B; Shear, H L


    The pathogenesis of anemia was studied in trypanosome-infected mice. A strain of Trypanosoma brucei, TREU 667, was used which first produces an acute phase marked by waves of parasitemia. Erythrocytes from infected animals were coated with immunoglobulin M during or just before the waves of anemia and parasitological crises. Erythrocytes from normal animals could be sensitized with "precrisis" sera presumably containing antigen and antibody. These data suggest that anemia during the acute phase is due to sensitization of erythrocytes with immunoglobulin M-antigen complexes. The anemia is partially compensated by a strong erythropoietic response. The acute phase is followed by a chronic phase marked by a constant high parasitemia and immunosuppression. The less marked anemia occurring during this latter phase is due to hemodilution and perhaps a low but significant immune response to the parasites, which causes continuing erythrocyte sensitization by immunoglobulin M-antigen complexes. PMID:7201455

  15. Trypanosoma brucei: a putative RNA polymerase II promoter. (United States)

    Bayele, Henry K


    RNA polymerase II (pol II) promoters are rare in the African trypanosome Trypanosoma brucei because gene regulation in the parasite is complex and polycistronic. Here, we describe a putative pol II promoter and its structure-function relationship. The promoter has features of an archetypal eukaryotic pol II promoter including putative canonical CCAAT and TATA boxes, and an initiator element. However, the spatial arrangement of these elements is only similar to yeast pol II promoters. Deletion mapping and transcription assays enabled delineation of a minimal promoter that could drive orientation-independent reporter gene expression suggesting that it may be a bidirectional promoter. In vitro transcription in a heterologous nuclear extract revealed that the promoter can be recognized by the basal eukaryotic transcription complex. This suggests that the transcription machinery in the parasite may be very similar to those of other eukaryotes.

  16. Febrile Seizure: Demographic Features and Causative Factors

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    Full Text Available ObjectiveBecause of geographical and periodical variation, we prompted to determine the demographic features and causative factors for febrile seizure in Rasht.Materials & MethodsIn this cross-sectional study, all 6–month- to 6-year-old children with the diagnosis of febrile seizure admitted to 17 Shahrivar hospital in Rasht, from August, 2009 to August, 2010 were studied. Age, sex, family history of the disease, seizure types, body temperature upon admission and infectious causes of the fever were recorded. All statistical analysis was performed with SPSS software, version 16.ResultsOf the 214 children (mean age, 25.24±15.40 months, 124 were boys and 109 had a positive family history. Complex seizures were seen in 39 cases. In patients with a complex febrile seizure, 59% had the repetitive type, 20.5% had the focal type and 20.5% had more than 15 minutes duration of seizures. Most of the repetitive seizures (78.3% occurred in patients under 2 years old; the difference between under and over 2-year-old patients was statistically significant (P=0.02. Study results did not show significant differences between the two genders for simple or complex seizures. The mean body temperature upon admission was 38.2±1.32◦C (38.31±0.82 degrees in boys and 38.04±1.78 in girls. Upper respiratory infections were seen in most patients (74.29%. All cases of lower respiratory infections were boys. There was a statistically significant difference between boys and girls in causes of fever.ConclusionMost of the children had a positive family history and the most common causative factor was upper respiratory infection.

  17. MIF Contributes to Trypanosoma brucei Associated Immunopathogenicity Development (United States)

    Stijlemans, Benoît; Leng, Lin; Brys, Lea; Sparkes, Amanda; Vansintjan, Liese; Caljon, Guy; Raes, Geert; Van Den Abbeele, Jan; Van Ginderachter, Jo A.; Beschin, Alain


    African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6Chigh inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor) as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury), and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity. PMID:25255103

  18. MIF contributes to Trypanosoma brucei associated immunopathogenicity development.

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    Benoît Stijlemans


    Full Text Available African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6C(high inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury, and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity.

  19. Exosome secretion affects social motility in Trypanosoma brucei (United States)

    Shaked, Hadassa; Arvatz, Gil; Tkacz, Itai Dov; Binder, Lior; Waldman Ben-Asher, Hiba; Okalang, Uthman; Chikne, Vaibhav; Cohen-Chalamish, Smadar; Michaeli, Shulamit


    Extracellular vesicles (EV) secreted by pathogens function in a variety of biological processes. Here, we demonstrate that in the protozoan parasite Trypanosoma brucei, exosome secretion is induced by stress that affects trans-splicing. Following perturbations in biogenesis of spliced leader RNA, which donates its spliced leader (SL) exon to all mRNAs, or after heat-shock, the SL RNA is exported to the cytoplasm and forms distinct granules, which are then secreted by exosomes. The exosomes are formed in multivesicular bodies (MVB) utilizing the endosomal sorting complexes required for transport (ESCRT), through a mechanism similar to microRNA secretion in mammalian cells. Silencing of the ESCRT factor, Vps36, compromised exosome secretion but not the secretion of vesicles derived from nanotubes. The exosomes enter recipient trypanosome cells. Time-lapse microscopy demonstrated that cells secreting exosomes or purified intact exosomes affect social motility (SoMo). This study demonstrates that exosomes are delivered to trypanosome cells and can change their migration. Exosomes are used to transmit stress signals for communication between parasites. PMID:28257521

  20. Proteins associated with SF3a60 in T. brucei.

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    Benson Nyambega

    Full Text Available Trypanosoma brucei relies on Spliced leader trans splicing to generate functional messenger RNAs. Trans splicing joins the specialized SL exon from the SL RNA to pre-mRNAs and is mediated by the trans-spliceosome, which is made up of small nuclear ribonucleoprotein particles and non-snRNP factors. Although the trans spliceosome is essential for trypanosomatid gene expression, not all spliceosomal protein factors are known and of these, only a few are completely characterized. In this study, we have characterized the trypanosome Splicing Factor, SF3a60, the only currently annotated SF3a component. As expected, epitope-tagged SF3a60 localizes in the trypanosome nucleus. SF3a60 is essential for cell viability but its depletion seem to have no detectable effect on trans-splicing. In addition, we used SF3a60 as bait in a Yeast-2-hybrid system screen and identified its interacting protein factors. The interactions with SF3a120, SF3a66 and SAP130 were confirmed by tandem affinity purification and mass spectrometry.

  1. Proteomics and the Trypanosoma brucei cytoskeleton: advances and opportunities. (United States)

    Portman, Neil; Gull, Keith


    Trypanosoma brucei is the etiological agent of devastating parasitic disease in humans and livestock in sub-saharan Africa. The pathogenicity and growth of the parasite are intimately linked to its shape and form. This is in turn derived from a highly ordered microtubule cytoskeleton that forms a tightly arrayed cage directly beneath the pellicular membrane and numerous other cytoskeletal structures such as the flagellum. The parasite undergoes extreme changes in cellular morphology during its life cycle and cell cycles which require a high level of integration and coordination of cytoskeletal processes. In this review we will discuss the role that proteomics techniques have had in advancing our understanding of the molecular composition of the cytoskeleton and its functions. We then consider future opportunities for the application of these techniques in terms of addressing some of the unanswered questions of trypanosome cytoskeletal cell biology with particular focus on the differences in the composition and organisation of the cytoskeleton through the trypanosome life-cycle.

  2. Febrile Seizure: Demographic Features and Causative Factors

    Directory of Open Access Journals (Sweden)



    Full Text Available How to cite this article: Esmaili Gourabi H, Bidabadi E, Cheraghalipour  F, Aarabi  Y, Salamat F. Febrile Seizure: Demographic Features and Causative Factors. Iran J Child Neurol Autumn 2012; 6(4:33-37.Abstract Objective Because of geographical and periodical variation, we prompted to determine the demographic features and causative factors for febrile seizure in Rasht. Materials & Methods In this cross-sectional study, all 6–month- to 6-year-old children with the diagnosis of febrile seizure admitted to 17 Shahrivar hospital in Rasht, from August, 2009 to August, 2010 were studied. Age, sex, family history of the disease, seizure types, body temperature upon admission and infectious causes of the fever were recorded. All statistical analysis was performed with SPSS software, version 16. Results Of the 214 children (mean age, 25.24±15.40 months, 124 were boys and 109 had a positive family history. Complex seizures were seen in 39 cases. In patients with a complex febrile seizure, 59% had the repetitive type, 20.5% had the focal type and 20.5% had more than 15 minutes duration of seizures. Most of the repetitive seizures (78.3% occurred in patients under 2 years old; the difference between under and over 2-year-old patients was statistically significant (P=0.02. Study results did not show significant differences between the two genders for simple or complex seizures. The mean body temperature upon admission was 38.2±1.32◦C (38.31±0.82 degrees in boys and 38.04±1.78 in girls. Upper respiratory infections were seen in most patients (74.29%. All cases of lower respiratory infections were boys. There was a statistically significant difference between boys and girls in causes of fever. Conclusion Most of the children had a positive family history and the most common causative factor was upper respiratory infection.  References: Huang MC, Huang CC, Thomas K. Febrile convulsions: development and validation of a questionnaire to measure

  3. A trans-spliced telomerase RNA dictates telomere synthesis in Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    Ranjodh Sandhu; Samantha Sanford; Shrabani Basu; MinA Park; Unnati M Pandya; Bibo Li; Kausik Chakrabarti


    Telomerase is a ribonucleoprotein enzyme typically required for sustained cell proliferation.Although both telomerase activity and the telomerase catalytic protein component,TbTERT,have been identified in the eukaryotic pathogen Trypanosoma brucei,the RNA molecule that dictates telomere synthesis remains unknown.Here,we identify the RNA component of Trypanosoma brucei telomerase,TbTR,and provide phylogenetic and in vivo evidence for TbTR's native folding and activity.We show that TbTR is processed through trans-splicing,and is a capped transcript that interacts and copurifies with TbTERT in vivo.Deletion of TbTR caused progressive shortening of telomeres at a rate of 3-5 bp/population doubling (PD),which can be rescued by ectopic expression of a wild-type allele of TbTR in an apparent dose-dependent manner.Remarkably,introduction of mutations in the TbTR template domain resulted in corresponding mutant telomere sequences,demonstrating that telomere synthesis in T.brucei is dependent on TbTR.We also propose a secondary structure model for TbTR based on phylogenetic analysis and chemical probing experiments,thus defining TbTR domains that may have important functional implications in telomere synthesis.Identification and characterization of TbTR not only provide important insights into T.brucei telomere functions,which have been shown to play important roles in T.brucei pathogenesis,but also offer T.brucei as an attractive model system for studying telomerase biology in pathogenic protozoa and for comparative analysis of telomerase function with higher eukaryotes.

  4. Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Alloatti, Andres [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Gupta, Shreedhara; Gualdron-Lopez, Melisa; Nguewa, Paul A. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Altabe, Silvia G. [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Deumer, Gladys; Wallemacq, Pierre [Department of Clinical Chemistry, Cliniques Universitaires Saint-Luc, LTAP, Universite Catholique de Louvain, Brussels (Belgium); Michels, Paul A.M. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Uttaro, Antonio D., E-mail: [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina)


    Highlights: {yields} Inhibiting {Delta}9 desaturase drastically changes T. brucei's fatty-acid composition. {yields} Isoxyl specifically inhibits the {Delta}9 desaturase causing a growth arrest. {yields} RNA interference of desaturase expression causes a similar effect. {yields} Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. {yields} 70% of Isoxyl-treated mice survived the trypanosome infection. -- Abstract: Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes named desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC{sub 50}) of PCF was 1.0 {+-} 0.2 {mu}M for Isoxyl and 5 {+-} 2 {mu}M for 10-TS, whereas BSF appeared more susceptible with EC{sub 50} values 0.10 {+-} 0.03 {mu}M (Isoxyl) and 1.0 {+-} 0.6 {mu}M (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.

  5. Diverse effects on mitochondrial and nuclear functions elicited by drugs and genetic knockdowns in bloodstream stage Trypanosoma brucei.

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    Christal Worthen

    Full Text Available BACKGROUND: The options for treating the fatal disease human African trypanosomiasis are limited to a few drugs that are toxic or facing increasing resistance. New drugs that kill the causative agents, subspecies of Trypanosoma brucei, are therefore urgently needed. Little is known about the cellular mechanisms that lead to death of the pathogenic bloodstream stage. METHODOLOGY/PRINCIPAL FINDINGS: We therefore conducted the first side by side comparison of the cellular effects of multiple death inducers that target different systems in bloodstream form parasites, including six drugs (pentamidine, prostaglandin D(2, quercetin, etoposide, camptothecin, and a tetrahydroquinoline and six RNAi knockdowns that target distinct cellular functions. All compounds tested were static at low concentrations and killed at high concentrations. Dead parasites were rapidly quantified by forward and side scatter during flow cytometry, as confirmed by ethidium homodimer and esterase staining, making these assays convenient for quantitating parasite death. The various treatments yielded different combinations of defects in mitochondrial potential, reactive oxygen species, cell cycle, and genome segregation. No evidence was seen for phosphatidylserine exposure, a marker of apoptosis. Reduction in ATP levels lagged behind decreases in live cell number. Even when the impact on growth was similar at 24 hours, drug-treated cells showed dramatic differences in their ability to further proliferate, demonstrating differences in the reversibility of effects induced by the diverse compounds. CONCLUSIONS/SIGNIFICANCE: Parasites showed different phenotypes depending on the treatment, but none of them were clear predictors of whether apparently live cells could go on to proliferate after drugs were removed. We therefore suggest that clonal proliferation assays may be a useful step in selecting anti-trypanosomal compounds for further development. Elucidating the genetic or

  6. Factual and legal causation - their relation to negligence in nursing. (United States)

    Turton, Gemma

    Several elements must be shown to be fulfilled for a court to hold that negligence has occurred, and a person is liable. One of these elements is 'causation', the idea that there must be a causal link between the claimant's loss and the negligent behaviour of the defendant. This article considers the application of the tests of factual and legal causation to cases of medical negligence. It is argued that in light of the recent development of a number of exceptional approaches to factual causation, each relating to a particular causal problem, the causal process must be identified in any given case so that the correct test for factual causation can be applied. This is illustrated by reference to MRSA claims. It is further argued that where the negligence consists of misdiagnosis or mistreatment of existing illness the causal problem is unique to medical negligence and demands a unique approach to causation. The 'scope of duty' test for legal causation is illustrated in a medical context and it is argued that where the negligence consists of a failure to warn the patient of the risks involved in treatment, although the harm is clearly within the scope of the doctor's duty, it is wrong to establish liability in the absence of factual causation.

  7. The cell cycle regulated transcriptome of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Stuart K Archer

    Full Text Available Progression of the eukaryotic cell cycle requires the regulation of hundreds of genes to ensure that they are expressed at the required times. Integral to cell cycle progression in yeast and animal cells are temporally controlled, progressive waves of transcription mediated by cell cycle-regulated transcription factors. However, in the kinetoplastids, a group of early-branching eukaryotes including many important pathogens, transcriptional regulation is almost completely absent, raising questions about the extent of cell-cycle regulation in these organisms and the mechanisms whereby regulation is achieved. Here, we analyse gene expression over the Trypanosoma brucei cell cycle, measuring changes in mRNA abundance on a transcriptome-wide scale. We developed a "double-cut" elutriation procedure to select unperturbed, highly synchronous cell populations from log-phase cultures, and compared this to synchronization by starvation. Transcriptome profiling over the cell cycle revealed the regulation of at least 430 genes. While only a minority were homologous to known cell cycle regulated transcripts in yeast or human, their functions correlated with the cellular processes occurring at the time of peak expression. We searched for potential target sites of RNA-binding proteins in these transcripts, which might earmark them for selective degradation or stabilization. Over-represented sequence motifs were found in several co-regulated transcript groups and were conserved in other kinetoplastids. Furthermore, we found evidence for cell-cycle regulation of a flagellar protein regulon with a highly conserved sequence motif, bearing similarity to consensus PUF-protein binding motifs. RNA sequence motifs that are functional in cell-cycle regulation were more widespread than previously expected and conserved within kinetoplastids. These findings highlight the central importance of post-transcriptional regulation in the proliferation of parasitic kinetoplastids.

  8. Licensing of Instrumental Case in Hindi/Urdu Causatives

    Directory of Open Access Journals (Sweden)

    Gillian Ramchand


    Full Text Available In this paper, I revisit the licensing and interpretation of instrumental case-marked nominals in Hindi/Urdu causative constructions to argue against the hypothesis that the se-marked phrase corresponds to a demoted agent. Rather, I will argue that a more unified analysis of se-phrases can be achieved through an event-structural analysis, in line with the standard interpretation of other adverbials in the syntax. Since the ‘intermediate agent’ interpretation is only possible with indirect causatives in Hindi/Urdu, the event structural analysis proposed here also has implications for the direct vs. indirect causation distinction in the syntax.

  9. Isolation and characterization of kinetoplast DNA from the bloodstream form of Trypanosoma brucei.

    NARCIS (Netherlands)

    A.H. Fairlamb; P.O. Weislogel; J.H.J. Hoeijmakers (Jan); P. Borst (Piet)


    textabstractWe have used restriction endonucleases PstI, EcoRI, HapII, HhaI, and S1 nuclease to demonstrate the presence of a large complex component, the maxi-circle, in addition to the major mini-circle component in kinetoplast DNA (kDNA) networks of Trypanosoma brucei (East African Trypanosomiasi

  10. A search for Trypanosoma brucei rhodesiense diagnostic antigens by proteomic screening and targeted cloning.

    Directory of Open Access Journals (Sweden)

    Theresa Manful

    Full Text Available BACKGROUND: The only available diagnostic method for East African trypanosomiasis is light microscopy of blood samples. A simple immunodiagnostic would greatly aid trypanosomiasis control. METHODOLOGY AND PRINCIPAL FINDINGS: To find trypanosome proteins that are specifically recognised by sera from human sleeping sickness patients, we have screened the Trypanosoma brucei brucei proteome by Western blotting. Using cytosolic, cytoskeletal and glycosomal fractions, we found that the vast majority of abundant trypanosome proteins is not specifically recognised by patient sera. We identified phosphoglycerate kinase (PGKC, heat shock protein (HSP70, and histones H2B and H3 as possible candidate diagnostic antigens. These proteins, plus paraflagellar rod protein 1, rhodesain (a cysteine protease, and an extracellular fragment of the Trypanosoma brucei nucleoside transporter TbNT10, were expressed in E. coli and tested for reactivity with patient and control sera. Only TbHSP70 was preferentially recognized by patient sera, but the sensitivity and specificity were insufficient for use of TbHSP70 alone as a diagnostic. Immunoprecipitation using a native protein extract revealed no specifically reacting proteins. CONCLUSIONS: No abundant T. brucei soluble, glycosomal or cytoskeletal protein is likely to be useful in diagnosis. To find useful diagnostic antigens it will therefore be necessary to use more sophisticated proteomic methods, or to test a very large panel of candidate proteins.

  11. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation

    NARCIS (Netherlands)

    Weelden, van S.W.H.; Fast, B.; Vogt, A.; Meer, van der P.; Saas, J.; Hellemond, van J.J.; Tielens, A.G.M.; Boshart, M.


    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene cod

  12. Dynamic Modelling under Uncertainty : The Case of Trypanosoma brucei Energy Metabolism

    NARCIS (Netherlands)

    Achcar, Fiona; Kerkhoven, Eduard J.; Bakker, Barbara M.; Barrett, Michael P.; Breitling, Rainer; Papin, Jason A.


    Kinetic models of metabolism require detailed knowledge of kinetic parameters. However, due to measurement errors or lack of data this knowledge is often uncertain. The model of glycolysis in the parasitic protozoan Trypanosoma brucei is a particularly well analysed example of a quantitative metabol

  13. Involvement of lysosomes in the uptake of macromolecular material by bloodstream forms of Trypanosoma brucei. (United States)

    Opperdoes, F R; Van Roy, J


    To investigate whether the lysosomes of Trypanosoma brucei are capable of uptake of macromolecules after internalization by the cell, we used Triton WR-1339, a non-digestible macromolecular compound, which is known to cause a marked decrease in the density of hepatic lysosomes due to massive intralysosomal storage. Intraperitoneal administration of 0.4 g/kg Triton WR-1339 to rats infected with T. brucei led to the development of a large vacuole in the trypanosomes between nucleus and kinetoplast within 22 h. Higher doses (2 g/kg) led to the disappearance of the trypanosomes from the blood and resulted in permanent cures (greater than 100 days). Lysosomes isolated from the trypanosomes of animals treated with a sub-curative dose showed a decrease in equilibrium density of 0.03 g/cm3 in sucrose gradients. These lysosomes were partly damaged as evidenced by a reduction in latency and an increase in the non-sedimentable part of lysosomal enzymes. We conclude that acid proteinase and alpha-mannosidase-containing organelles of T. brucei take up exogenous macromolecules and must therefore be considered as true lysosomes and that Triton WR-1339 acts in T. brucei as a true lysosomotropic drug. Its trypanocidal action probably results from an interference with lysosomal function.

  14. Novel molecular mechanism for targeting the parasite Trypanosoma brucei with snake venom toxins

    DEFF Research Database (Denmark)

    Martos Esteban, Andrea; Laustsen, Andreas Hougaard; Carrington, Mark

    Trypanosoma brucei is a parasitic protozoan species capable to infecting insect vectors whose bite further produces African sleeping sickness inhuman beings. During parasites’extracellular lives in the mammalian host, its outer coat, mainly composedof Variable surface glycoproteins (VSGs)[2], und...

  15. Telomere length affects the frequency and mechanism of antigenic variation in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Galadriel A Hovel-Miner

    Full Text Available Trypanosoma brucei is a master of antigenic variation and immune response evasion. Utilizing a genomic repertoire of more than 1000 Variant Surface Glycoprotein-encoding genes (VSGs, T. brucei can change its protein coat by "switching" from the expression of one VSG to another. Each active VSG is monoallelically expressed from only one of approximately 15 subtelomeric sites. Switching VSG expression occurs by three predominant mechanisms, arguably the most significant of which is the non-reciprocal exchange of VSG containing DNA by duplicative gene conversion (GC. How T. brucei orchestrates its complex switching mechanisms remains to be elucidated. Recent work has demonstrated that an exogenous DNA break in the active site could initiate a GC based switch, yet the source of the switch-initiating DNA lesion under natural conditions is still unknown. Here we investigated the hypothesis that telomere length directly affects VSG switching. We demonstrate that telomerase deficient strains with short telomeres switch more frequently than genetically identical strains with long telomeres and that, when the telomere is short, switching preferentially occurs by GC. Our data supports the hypothesis that a short telomere at the active VSG expression site results in an increase in subtelomeric DNA breaks, which can initiate GC based switching. In addition to their significance for T. brucei and telomere biology, the findings presented here have implications for the many diverse pathogens that organize their antigenic genes in subtelomeric regions.

  16. Nucleic acid sequence-based amplification with oligochromatography for detection of Trypanosoma brucei in clinical samples

    NARCIS (Netherlands)

    C.M. Mugasa; T. Laurent; G.J. Schoone; P.A. Kager; G.W. Lubega; H.D.F.H. Schallig


    Molecular tools, such as real-time nucleic acid sequence-based amplification (NASBA) and PCR, have been developed to detect Trypanosoma brucei parasites in blood for the diagnosis of human African trypanosomiasis (HAT). Despite good sensitivity, these techniques are not implemented in HAT control pr

  17. Ribose 5-phosphate isomerase B knockdown compromises Trypanosoma brucei bloodstream form infectivity. (United States)

    Loureiro, Inês; Faria, Joana; Clayton, Christine; Macedo-Ribeiro, Sandra; Santarém, Nuno; Roy, Nilanjan; Cordeiro-da-Siva, Anabela; Tavares, Joana


    Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive drug target waiting further characterization. In this study, Trypanosoma brucei ribose 5-phosphate isomerase B showed in vitro isomerase activity. RNAi against this enzyme reduced parasites' in vitro growth, and more importantly, bloodstream forms infectivity. Mice infected with induced RNAi clones exhibited lower parasitaemia and a prolonged survival compared to control mice. Phenotypic reversion was achieved by complementing induced RNAi clones with an ectopic copy of Trypanosoma cruzi gene. Our results present the first functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B, and show the relevance of an enzyme belonging to the non-oxidative branch of the pentose phosphate pathway in the context of Trypanosoma brucei infection.

  18. The major transcripts of the kinetoplast Trypanosoma brucei are very small ribosomal RNA's.

    NARCIS (Netherlands)

    I.C. Eperon; J.W.G. Janssen; J.H.J. Hoeijmakers (Jan); P. Borst (Piet)


    textabstractThe nucleotide sequence has been determined of a 2.2 kb segment of kinetoplast DNA, which encodes the major mitochondrial transcripts (12S and 9S) of Trypanosoma brucei. The sequence shows that the 12S RNA is a large subunit rRNA, although sufficiently unusual for resistance to chloramph

  19. Biosynthesis of SUMOylated Proteins in Bacteria Using the Trypanosoma brucei Enzymatic System (United States)

    Iribarren, Paula Ana; Berazategui, María Agustina; Cazzulo, Juan José; Alvarez, Vanina Eder


    Post-translational modification with the Small Ubiquitin-like Modifier (SUMO) is conserved in eukaryotic organisms and plays important regulatory roles in proteins affecting diverse cellular processes. In Trypanosoma brucei, member of one of the earliest branches in eukaryotic evolution, SUMO is essential for normal cell cycle progression and is likely to be involved in the epigenetic control of genes crucial for parasite survival, such as those encoding the variant surface glycoproteins. Molecular pathways modulated by SUMO have started to be discovered by proteomic studies; however, characterization of functional consequences is limited to a reduced number of targets. Here we present a bacterial strain engineered to produce SUMOylated proteins, by transferring SUMO from T. brucei together with the enzymes essential for its activation and conjugation. Due to the lack of background in E. coli, this system is useful to express and identify SUMOylated proteins directly in cell lysates by immunoblotting, and SUMOylated targets can be eventually purified for biochemical or structural studies. We applied this strategy to describe the ability of TbSUMO to form chains in vitro and to detect SUMOylation of a model substrate, PCNA both from Saccharomyces cerevisiae and from T. brucei. To further validate targets, we applied an in vitro deconjugation assay using the T. brucei SUMO-specific protease capable to revert the pattern of modification. This system represents a valuable tool for target validation, mutant generation and functional studies of SUMOylated proteins in trypanosomatids. PMID:26258470

  20. A computable expression of closure to efficient causation. (United States)

    Mossio, Matteo; Longo, Giuseppe; Stewart, John


    In this paper, we propose a mathematical expression of closure to efficient causation in terms of lambda-calculus; we argue that this opens up the perspective of developing principled computer simulations of systems closed to efficient causation in an appropriate programming language. An important implication of our formulation is that, by exhibiting an expression in lambda-calculus, which is a paradigmatic formalism for computability and programming, we show that there are no conceptual or principled problems in realizing a computer simulation or model of closure to efficient causation. We conclude with a brief discussion of the question whether closure to efficient causation captures all relevant properties of living systems. We suggest that it might not be the case, and that more complex definitions could indeed create crucial some obstacles to computability.

  1. Al Ghazali and Hume on causation and miracles


    yazıcı, sedat


    This paper is an attempt to show the similarities and differences between Al Ghazali and Hume on causation and miracles. Such a comparison is interesting because, long before Hume, the issue of necessary causality had been taken up by the Islamic philosophers Al Ghazal in his book The Incoherence the Philosophers. Although Ghazali's and Hume's views on causation are strikingly parallel to one another in their empirical contention, there are still some differences to be noted. First, both reje...

  2. Mitochondrial outer membrane proteome of Trypanosoma brucei reveals novel factors required to maintain mitochondrial morphology. (United States)

    Niemann, Moritz; Wiese, Sebastian; Mani, Jan; Chanfon, Astrid; Jackson, Christopher; Meisinger, Chris; Warscheid, Bettina; Schneider, André


    Trypanosoma brucei is a unicellular parasite that causes devastating diseases in humans and animals. It diverged from most other eukaryotes very early in evolution and, as a consequence, has an unusual mitochondrial biology. Moreover, mitochondrial functions and morphology are highly regulated throughout the life cycle of the parasite. The outer mitochondrial membrane defines the boundary of the organelle. Its properties are therefore key for understanding how the cytosol and mitochondria communicate and how the organelle is integrated into the metabolism of the whole cell. We have purified the mitochondrial outer membrane of T. brucei and characterized its proteome using label-free quantitative mass spectrometry for protein abundance profiling in combination with statistical analysis. Our results show that the trypanosomal outer membrane proteome consists of 82 proteins, two-thirds of which have never been associated with mitochondria before. 40 proteins share homology with proteins of known functions. The function of 42 proteins, 33 of which are specific to trypanosomatids, remains unknown. 11 proteins are essential for the disease-causing bloodstream form of T. brucei and therefore may be exploited as novel drug targets. A comparison with the outer membrane proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. Known factors involved in the regulation of mitochondrial morphology are virtually absent in T. brucei. Interestingly, RNAi-mediated ablation of three outer membrane proteins of unknown function resulted in a collapse of the network-like mitochondrion of procyclic cells and for the first time identified factors that control mitochondrial shape in T. brucei.

  3. Mutational analysis of Trypanosoma brucei RNA editing ligase reveals regions critical for interaction with KREPA2.

    Directory of Open Access Journals (Sweden)

    Vaibhav Mehta

    Full Text Available The Trypanosoma brucei parasite causes the vector-borne disease African sleeping sickness. Mitochondrial mRNAs of T. brucei undergo posttranscriptional RNA editing to make mature, functional mRNAs. The final step of this process is catalyzed by the essential ligase, T. brucei RNA Editing Ligase 1 (TbREL1 and the closely related T. brucei RNA Editing Ligase 2 (TbREL2. While other ligases such as T7 DNA ligase have both a catalytic and an oligonucleotide/oligosaccharide-binding (OB-fold domain, T. brucei RNA editing ligases contain only the catalytic domain. The OB-fold domain, which is required for interaction with the substrate RNA, is provided in trans by KREPA2 (for TbREL1 and KREPA1 (for TbREL2. KREPA2 enhancement of TbREL1 ligase activity is presumed to occur via an OB-fold-mediated increase in substrate specificity and catalysis. We characterized the interaction between TbREL1 and KREPA2 in vitro using full-length, truncated, and point-mutated ligases. As previously shown, our data indicate strong, specific stimulation of TbREL1 catalytic activity by KREPA2. We narrowed the region of contact to the final 59 C-terminal residues of TbREL1. Specifically, the TbREL1 C-terminal KWKE (441-444 sequence appear to coordinate the KREPA2-mediated enhancement of TbREL1 activities. N-terminal residues F206, T264 and Y275 are crucial for the overall activity of TbREL1, particularly for F206, a mutation of this residue also disrupts KREPA2 interaction. Thus, we have identified the critical TbREL1 regions and amino acids that mediate the KREPA2 interaction.

  4. T rypanosoma brucei histone H1 inhibits RNA polymerase I transcription and is important for parasite fitness in vivo


    Pena, Ana C.; Pimentel, Mafalda R; Manso, Helena; Vaz-Drago, Rita; Pinto-Neves, Daniel; Aresta-Branco, Francisco; Rijo-Ferreira, Filipa; Guegan, Fabien; Pedro Coelho, Luis; Carmo-Fonseca, Maria; Barbosa-Morais, Nuno L.; Figueiredo, Luisa M.


    T rypanosoma brucei is a unicellular parasite that causes sleeping sickness in humans. Most of its transcription is constitutive and driven by RNA polymerase II. RNA polymerase I (Pol I) transcribes not only ribosomal RNA genes, but also protein-encoding genes, including variant surface glycoproteins (VSGs) and procyclins. In T . brucei, histone H1 (H1) is required for VSG silencing and chromatin condensation. However, whether H1 has a genome-wide role in transcription is unknown. Here, using...

  5. Hierarchy, causation and explanation: ubiquity, locality and pluralism. (United States)

    Love, Alan C


    The ubiquity of top-down causal explanations within and across the sciences is prima facie evidence for the existence of top-down causation. Much debate has been focused on whether top-down causation is coherent or in conflict with reductionism. Less attention has been given to the question of whether these representations of hierarchical relations pick out a single, common hierarchy. A negative answer to this question undermines a commonplace view that the world is divided into stratified 'levels' of organization and suggests that attributions of causal responsibility in different hierarchical representations may not have a meaningful basis for comparison. Representations used in top-down and bottom-up explanations are primarily 'local' and tied to distinct domains of science, illustrated here by protein structure and folding. This locality suggests that no single metaphysical account of hierarchy for causal relations to obtain within emerges from the epistemology of scientific explanation. Instead, a pluralist perspective is recommended-many different kinds of top-down causation (explanation) can exist alongside many different kinds of bottom-up causation (explanation). Pluralism makes plausible why different senses of top-down causation can be coherent and not in conflict with reductionism, thereby illustrating a productive interface between philosophical analysis and scientific inquiry.

  6. Event ontology in quantum mechanics and downward causation

    CERN Document Server

    Gambini, Rodolfo


    We show that several interpretations of quantum mechanics admit an ontology of objects and events. This ontology reduces the breach between mind and matter. When humans act, their actions do not appear explainable in mechanical terms but through mental activity: motives, desires or needs that propel them to action. These are examples of what in the last few decades have come to be called "downward causation". Basically, downward causation is present when the disposition of the whole to behave in a certain way cannot be predicted from the dispositions of the parts. The event ontology of quantum mechanics allow us to show that systems in entangled states present emergent new properties and downward causation.

  7. Backward Causation, Isolation and the Pursuit of Justice

    CERN Document Server

    Cirkovic, M M; Cirkovic, Milan M.; Cveticanin, Suzana


    The recent operationalization of the famous Newcomb's game by Schmidt (1998) offers an interesting and thought-provoking look at the plausibility of backward causation in a Newtonian universe. Hereby we investigate two details of the Schmidt's scenario which may, at least in principle, invalidate his conclusion in two different domains: one dealing with the issue of Newtonian predictability in specific instance of human actions, and the other stemming from a possible strategy aimed at obviating the anthropically oriented view of backward causation as applied to a judicial and ethical problem posed by a version of the scenario. We conclude that the scenario is at least to be more complex than originally presented in order to remain viable. However, it points to a very deep and delicate question of compatibility of backward causation with the conventional ethical standards.

  8. A theory of biological relativity: no privileged level of causation. (United States)

    Noble, Denis


    Must higher level biological processes always be derivable from lower level data and mechanisms, as assumed by the idea that an organism is completely defined by its genome? Or are higher level properties necessarily also causes of lower level behaviour, involving actions and interactions both ways? This article uses modelling of the heart, and its experimental basis, to show that downward causation is necessary and that this form of causation can be represented as the influences of initial and boundary conditions on the solutions of the differential equations used to represent the lower level processes. These insights are then generalized. A priori, there is no privileged level of causation. The relations between this form of 'biological relativity' and forms of relativity in physics are discussed. Biological relativity can be seen as an extension of the relativity principle by avoiding the assumption that there is a privileged scale at which biological functions are determined.

  9. Clinical and hematological study of Trypanosoma brucei and Trypanosoma congolense in cattle in Mosul City, Iraq

    Directory of Open Access Journals (Sweden)

    Al-Badrani, B. A


    Full Text Available An out-break of trypanosomosis was reported and subsequently investigated in Mosul city, Iraq. Twenty seven blood samples were received at the Clinical pathology Laboratory of Veterinary Teaching Hospital, University of Mosul, from fifteen cows (2-5 years old and twelve calves (10-12 months old of different farms located around Mosul city. Clinical signs of the infected animals revealed fever, progressive weight loss, anemia, and frequent recumbent position. Identification of trypanosome species were based on their motility using morphological differentiation on Giemsa or Leishman stained that showed trypomastigot which can be classified according to the biometrical data into T. brucei and T. congolense. A decreased was also observed in some blood parameters. To our knowledge, this is the first record of T. brucei and T. congolense infection in cattle. This study also suggested that trypanosomosis is associated with introduction of exotic breeds of cattle into Mosul, Iraq.

  10. Alkaloids Induce Programmed Cell Death in Bloodstream Forms of Trypanosomes (Trypanosoma b. brucei

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    Michael Wink


    Full Text Available The potential induction of a programmed cell death (PCD in Trypanosoma b. brucei by 55 alkaloids of the quinoline, quinolizidine, isoquinoline, indole, terpene, tropane, steroid, and piperidine type was studied by measuring DNA fragmentation and changes in mitochondrial membrane potential. For comparison, the induction of apoptosis by the same alkaloids in human leukemia cells (Jurkat APO-S was tested. Several alkaloids of the isoquinoline, quinoline, indole and steroidal type (berberine, chelerythrine, emetine, sanguinarine, quinine, ajmalicine, ergotamine, harmine, vinblastine, vincristine, colchicine, chaconine, demissidine and veratridine induced programmed cell death, whereas quinolizidine, tropane, terpene and piperidine alkaloids were mostly inactive. Effective PCD induction (EC50 below 10 µM was caused in T. brucei by chelerythrine, emetine, sanguinarine, and chaconine. The active alkaloids can be characterized by their general property to inhibit protein biosynthesis, to intercalate DNA, to disturb membrane fluidity or to inhibit microtubule formation.

  11. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Juan P de Macêdo


    Full Text Available Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug

  12. An essential signal peptide peptidase identified in an RNAi screen of serine peptidases of Trypanosoma brucei.

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    Catherine X Moss

    Full Text Available The serine peptidases of Trypanosoma brucei have been viewed as potential drug targets. In particular, the S9 prolyl oligopeptidase subfamily is thought to be a good avenue for drug discovery. This is based on the finding that some S9 peptidases are secreted and active in the mammalian bloodstream, and that they are a class of enzyme against which drugs have successfully been developed. We collated a list of all serine peptidases in T. brucei, identifying 20 serine peptidase genes, of which nine are S9 peptidases. We screened all 20 serine peptidases by RNAi to determine which, if any, are essential for bloodstream form T. brucei survival. All S9 serine peptidases were dispensable for parasite survival in vitro, even when pairs of similar genes, coding for oligopeptidase B or prolyl oligopeptidase, were targeted simultaneously. We also found no effect on parasite survival in an animal host when the S9 peptidases oligopeptidase B, prolyl oligopeptidase or dipeptidyl peptidase 8 were targeted. The only serine peptidase to emerge from the RNAi screen as essential was a putative type-I signal peptide peptidase (SPP1. This gene was essential for parasite survival both in vitro and in vivo. The growth defect conferred by RNAi depletion of SPP1 was rescued by expression of a functional peptidase from an RNAi resistant SPP1 gene. However, expression of catalytically inactive SPP1 was unable to rescue cells from the SPP1 depleted phenotype, demonstrating that SPP1 serine peptidase activity is necessary for T. brucei survival.

  13. A transcription-independent epigenetic mechanism is associated with antigenic switching in Trypanosoma brucei


    Aresta-Branco, Francisco; Pimenta, Silvia; Figueiredo, Luisa M.


    Antigenic variation in Trypanosoma brucei relies on periodic switching of variant surface glycoproteins (VSGs), which are transcribed monoallelically by RNA polymerase I from one of about 15 bloodstream expression sites (BES). Chromatin of the actively transcribed BES is depleted of nucleosomes, but it is unclear if this open conformation is a mere consequence of a high rate of transcription, or whether it is maintained by a transcription-independent mechanism. Using an inducible BES-silencin...

  14. Comparative analysis of the kinomes of three pathogenic trypanosomatids: Leishmania major, Trypanosoma brucei and Trypanosoma cruzi


    Parsons, Marilyn; Worthey, Elizabeth A.; Ward, Pauline N; Mottram, Jeremy C.


    Background The trypanosomatids Leishmania major, Trypanosoma brucei and Trypanosoma cruzi cause some of the most debilitating diseases of humankind: cutaneous leishmaniasis, African sleeping sickness, and Chagas disease. These protozoa possess complex life cycles that involve development in mammalian and insect hosts, and a tightly coordinated cell cycle ensures propagation of the highly polarized cells. However, the ways in which the parasites respond to their environment and coordinate intr...

  15. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation. (United States)

    van Weelden, Susanne W H; Fast, Beate; Vogt, Achim; van der Meer, Pieter; Saas, Joachim; van Hellemond, Jaap J; Tielens, Aloysius G M; Boshart, Michael


    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene coding for aconitase were derived by synchronous in vitro differentiation from wild type and mutant (Delta aco::NEO/Delta aco::HYG) bloodstream stage parasites, respectively, where aconitase is not expressed and is dispensable. No differences in intracellular levels of glycolytic and Krebs cycle intermediates were found in procyclic wild type and mutant cells, except for citrate that accumulated up to 90-fold in the mutants, confirming the absence of aconitase activity. Surprisingly, deletion of aconitase did not change differentiation nor the growth rate or the intracellular ATP/ADP ratio in those cells. Metabolic studies using radioactively labeled substrates and NMR analysis demonstrated that glucose and proline were not degraded via the Krebs cycle to CO(2). Instead, glucose was degraded to acetate, succinate, and alanine, whereas proline was degraded to succinate. Importantly, there was absolutely no difference in the metabolic products released by wild type and aconitase knockout parasites, and both were for survival strictly dependent on respiration via the mitochondrial electron transport chain. Hence, although the Krebs cycle enzymes are present, procyclic T. brucei do not use Krebs cycle activity for energy generation, but the mitochondrial respiratory chain is essential for survival and growth. We therefore propose a revised model of the energy metabolism of procyclic T. brucei.

  16. The extraordinary mitochondrion and unusual citric acid cycle in Trypanosoma brucei. (United States)

    van Hellemond, J J; Opperdoes, F R; Tielens, A G M


    African trypanosomes are parasitic protozoa that cause sleeping sickness and nagana. Trypanosomes are not only of scientific interest because of their clinical importance, but also because these protozoa contain several very unusual biological features, such as their specially adapted mitochondrion and the compartmentalization of glycolytic enzymes in glycosomes. The energy metabolism of Trypanosoma brucei differs significantly from that of their hosts and changes drastically during the life cycle. Despite the presence of all citric acid cycle enzymes in procyclic insect-stage T. brucei, citric acid cycle activity is not used for energy generation. Recent investigations on the influence of substrate availability on the type of energy metabolism showed that absence of glycolytic substrates did not induce a shift from a fermentative metabolism to complete oxidation of substrates. Apparently, insect-stage T. brucei use parts of the citric acid cycle for other purposes than for complete degradation of mitochondrial substrates. Parts of the cycle are suggested to be used for (i) transport of acetyl-CoA units from the mitochondrion to the cytosol for the biosynthesis of fatty acids, (ii) degradation of proline and glutamate to succinate, (iii) generation of malate, which can then be used for gluconeogenesis. Therefore the citric acid cycle in trypanosomes does not function as a cycle.

  17. Experimental Trypanosoma brucei infection at immediate post partum period:effects on dam and the offspring

    Institute of Scientific and Technical Information of China (English)

    Izuchukwu S Ochiogu; Chukwuka N Uchendu; John I Ihedioha


    Objective:To investigate the effects of immediate post-partum infection with Trypanosoma brucei (T. brucei) on dam and offspring. Methods:Sixty female Albino rats (Rattus norvegicus) weighing between 130-170 g were used as animal model. The animals were divided as follows:25 infected between 1-5 days post partum; 10 infected unbred as positive controls; and 25 uninfected as negative controls. The following parameters were evaluated:packed cell volume (PCV), level of parasitaemia, survival time, litter size and litter weight at birth and on days 7, 14 and 21 post delivery, using conventional methods. Possible trans-mammary transmission of infection to litter through milk was also assessed. Results:The results showed a comparatively (P<0.05) higher mean PCV value for the uninfected negative control on the 8th day post infection compared with the infected groups which corresponded with the increasing level of parasitaemia in the two infected groups. Mean litter size and litter weights were higher (P< 0.05) in the uninfected controls on the 21st day. Survival time in the infected groups were similar. No evidence of trans-mammary transfer of infection was recorded. Conclusion:T. brucei infection during immediate post partum period is detrimental to the dam and impairs growth of the offspring.

  18. Advancing Trypanosoma brucei genome annotation through ribosome profiling and spliced leader mapping. (United States)

    Parsons, Marilyn; Ramasamy, Gowthaman; Vasconcelos, Elton J R; Jensen, Bryan C; Myler, Peter J


    Since the initial publication of the trypanosomatid genomes, curation has been ongoing. Here we make use of existing Trypanosoma brucei ribosome profiling data to provide evidence of ribosome occupancy (and likely translation) of mRNAs from 225 currently unannotated coding sequences (CDSs). A small number of these putative genes correspond to extra copies of previously annotated genes, but 85% are novel. The median size of these novels CDSs is small (81 aa), indicating that past annotation work has excelled at detecting large CDSs. Of the unique CDSs confirmed here, over half have candidate orthologues in other trypanosomatid genomes, most of which were not yet annotated as protein-coding genes. Nonetheless, approximately one-third of the new CDSs were found only in T. brucei subspecies. Using ribosome footprints, RNA-Seq and spliced leader mapping data, we updated previous work to definitively revise the start sites for 414 CDSs as compared to the current gene models. The data pointed to several regions of the genome that had sequence errors that altered coding region boundaries. Finally, we consolidated this data with our previous work to propose elimination of 683 putative genes as protein-coding and arrive at a view of the translatome of slender bloodstream and procyclic culture form T. brucei.

  19. Discovery of Inhibitors of Trypanosoma brucei by Phenotypic Screening of a Focused Protein Kinase Library. (United States)

    Woodland, Andrew; Thompson, Stephen; Cleghorn, Laura A T; Norcross, Neil; De Rycker, Manu; Grimaldi, Raffaella; Hallyburton, Irene; Rao, Bhavya; Norval, Suzanne; Stojanovski, Laste; Brun, Reto; Kaiser, Marcel; Frearson, Julie A; Gray, David W; Wyatt, Paul G; Read, Kevin D; Gilbert, Ian H


    A screen of a focused kinase inhibitor library against Trypanosoma brucei rhodesiense led to the identification of seven series, totaling 121 compounds, which showed >50 % inhibition at 5 μm. Screening of these hits in a T. b. brucei proliferation assay highlighted three compounds with a 1H-imidazo[4,5-b]pyrazin-2(3H)-one scaffold that showed sub-micromolar activity and excellent selectivity against the MRC5 cell line. Subsequent rounds of optimisation led to the identification of compounds that exhibited good in vitro drug metabolism and pharmacokinetics (DMPK) properties, although in general this series suffered from poor solubility. A scaffold-hopping exercise led to the identification of a 1H-pyrazolo[3,4-b]pyridine scaffold, which retained potency. A number of examples were assessed in a T. b. brucei growth assay, which could differentiate static and cidal action. Compounds from the 1H-imidazo[4,5-b]pyrazin-2(3H)-one series were found to be either static or growth-slowing and not cidal. Compounds with the 1H-pyrazolo[3,4-b]pyridine scaffold were found to be cidal and showed an unusual biphasic nature in this assay, suggesting they act by at least two mechanisms.

  20. NLP is a novel transcription regulator involved in VSG expression site control in Trypanosoma brucei. (United States)

    Narayanan, Mani Shankar; Kushwaha, Manish; Ersfeld, Klaus; Fullbrook, Alexander; Stanne, Tara M; Rudenko, Gloria


    Trypanosoma brucei mono-allelically expresses one of approximately 1500 variant surface glycoprotein (VSG) genes while multiplying in the mammalian bloodstream. The active VSG is transcribed by RNA polymerase I in one of approximately 15 telomeric VSG expression sites (ESs). T. brucei is unusual in controlling gene expression predominantly post-transcriptionally, and how ESs are mono-allelically controlled remains a mystery. Here we identify a novel transcription regulator, which resembles a nucleoplasmin-like protein (NLP) with an AT-hook motif. NLP is key for ES control in bloodstream form T. brucei, as NLP knockdown results in 45- to 65-fold derepression of the silent VSG221 ES. NLP is also involved in repression of transcription in the inactive VSG Basic Copy arrays, minichromosomes and procyclin loci. NLP is shown to be enriched on the 177- and 50-bp simple sequence repeats, the non-transcribed regions around rDNA and procyclin, and both active and silent ESs. Blocking NLP synthesis leads to downregulation of the active ES, indicating that NLP plays a role in regulating appropriate levels of transcription of ESs in both their active and silent state. Discovery of the unusual transcription regulator NLP provides new insight into the factors that are critical for ES control.

  1. Identification of potent inhibitors of the Trypanosoma brucei methionyl-tRNA synthetase via high-throughput orthogonal screening. (United States)

    Pedró-Rosa, Laura; Buckner, Frederick S; Ranade, Ranae M; Eberhart, Christina; Madoux, Franck; Gillespie, J Robert; Koh, Cho Yeow; Brown, Steven; Lohse, Jacqueline; Verlinde, Christophe L M; Fan, Erkang; Bannister, Thomas; Scampavia, Louis; Hol, Wim G J; Spicer, Timothy; Hodder, Peter


    Improved therapies for the treatment of Trypanosoma brucei, the etiological agent of the neglected tropical disease human African trypanosomiasis, are urgently needed. We targeted T. brucei methionyl-tRNA synthetase (MetRS), an aminoacyl-tRNA synthase (aaRS), which is considered an important drug target due to its role in protein synthesis, cell survival, and its significant differences in structure from its mammalian ortholog. Previous work using RNA interference of MetRS demonstrated growth inhibition of T. brucei, further validating it as an attractive target. We report the development and implementation of two orthogonal high-throughput screening assays to identify inhibitors of T. brucei MetRS. First, a chemiluminescence assay was implemented in a 1536-well plate format and used to monitor adenosine triphosphate depletion during the aminoacylation reaction. Hit confirmation then used a counterscreen in which adenosine monophosphate production was assessed using fluorescence polarization technology. In addition, a miniaturized cell viability assay was used to triage cytotoxic compounds. Finally, lower throughput assays involving whole parasite growth inhibition of both human and parasite MetRS were used to analyze compound selectivity and efficacy. The outcome of this high-throughput screening campaign has led to the discovery of 19 potent and selective T. brucei MetRS inhibitors.

  2. The Centriole Cartwheel Protein SAS-6 in Trypanosoma brucei Is Required for Probasal Body Biogenesis and Flagellum Assembly. (United States)

    Hu, Huiqing; Liu, Yi; Zhou, Qing; Siegel, Sara; Li, Ziyin


    The centriole in eukaryotes functions as the cell's microtubule-organizing center (MTOC) to nucleate spindle assembly, and its biogenesis requires an evolutionarily conserved protein, SAS-6, which assembles the centriole cartwheel. Trypanosoma brucei, an early branching protozoan, possesses the basal body as its MTOC to nucleate flagellum biogenesis. However, little is known about the components of the basal body and their roles in basal body biogenesis and flagellum assembly. Here, we report that the T. brucei SAS-6 homolog, TbSAS-6, is localized to the mature basal body and the probasal body throughout the cell cycle. RNA interference (RNAi) of TbSAS-6 inhibited probasal body biogenesis, compromised flagellum assembly, and caused cytokinesis arrest. Surprisingly, overexpression of TbSAS-6 in T. brucei also impaired probasal body duplication and flagellum assembly, contrary to SAS-6 overexpression in humans, which produces supernumerary centrioles. Furthermore, we showed that depletion of T. brucei Polo-like kinase, TbPLK, or inhibition of TbPLK activity did not abolish TbSAS-6 localization to the basal body, in contrast to the essential role of Polo-like kinase in recruiting SAS-6 to centrioles in animals. Altogether, these results identified the essential role of TbSAS-6 in probasal body biogenesis and flagellum assembly and suggest the presence of a TbPLK-independent pathway governing basal body duplication in T. brucei.

  3. Complement sentences - complementizers of causative-manipulative verbs

    Directory of Open Access Journals (Sweden)

    Alanović Milivoj B.


    Full Text Available This paper presents the key structural and semantic features of the complement sentences that have the primary function of direct or indirect objects of one type of causative verbs - causative-manipulative verbs. Since the syntactic literature frequently discusses the structural characteristics of the complement sentences, the main objective of this article is focused on the semantic diversity of this type of sentences. The goal of the article is to determine the dependence of the realized meaning of a sentence on the semantic type of the main verb. Although the conjunction da is a typical subordinator of these sentences, a series of communicative verbs allows the use of complement sentences with interrogative adverbs and pronouns in the function of conjunctions. [Projekat Ministarstva nauke Republike Srbije, br.178004: Standardni srpski jezik - sintaksička, semantička i pragmatička istraživanja

  4. Game of Objects: vicarious causation and multi-modal media

    Directory of Open Access Journals (Sweden)

    Aaron Pedinotti


    Full Text Available This paper applies philosopher Graham Harman's object-oriented theory of "vicarious causation" to an analysis of the multi-modal media phenomenon known as "Game of Thrones." Examining the manner in which George R.R. Martin's best-selling series of fantasy novels has been adapted into a board game, a video game, and a hit HBO television series, it uses the changes entailed by these processes to trace the contours of vicariously generative relations. In the course of the resulting analysis, it provides new suggestions concerning the eidetic dimensions of Harman's causal model, particularly with regard to causation in linear networks and in differing types of game systems.

  5. Evidence for ecological causation of sexual dimorphism in a hummingbird. (United States)

    Temeles, E J; Pan, I L; Brennan, J L; Horwitt, J N


    Unambiguous examples of ecological causes of animal sexual dimorphism are rare. Here we present evidence for ecological causation of sexual dimorphism in the bill morphology of a hummingbird, the purple-throated carib. This hummingbird is the sole pollinator of two Heliconia species whose flowers correspond to the bills of either males or females. Each sex feeds most quickly at the flower species approximating its bill dimensions, which supports the hypothesis that floral specialization has driven the evolution of bill dimorphism. Further evidence for ecological causation of sexual dimorphism was provided by a geographic replacement of one Heliconia species by the other and the subsequent development of a floral dimorphism, with one floral morph matching the bills of males and the other of females.

  6. Distribution territories and causative mechanisms of ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Rovira, A.; Grive, E.; Alvarez-Sabin, J. [Unidad de Resonancia Magnetica, Hospital Vall d' Hebron, Barcelona (Spain)


    Ischemic stroke prognosis, risk of recurrence, clinical assessment, and treatment decisions are influenced by stroke subtype (anatomic distribution and causative mechanism of infarction). Stroke subtype diagnosis is better achieved in the early phase of acute ischemia with the use of multimodal MR imaging. The pattern of brain lesions as shown by brain MR imaging can be classified according to a modified Oxfordshire method, based on the anatomic distribution of the infarcts into six groups: (1) total anterior circulation infarcts, (2) partial anterior circulation infarcts, (3) posterior circulation infarcts, (4) watershed infarcts, (5) centrum ovale infarcts, and (6) lacunar infarcts. The subtype of stroke according to its causative mechanism is based on the TOAST method, which classifies stroke into five major etiologic groups: (1) large-vessel atherosclerotic disease, (2) small-vessel atherosclerotic disease, (3) cardioembolic source, (4) other determined etiologies, and (5) undetermined or multiple possible etiologies. The different MR imaging patterns of acute ischemic brain lesions visualized using diffusion-weighted imaging and the pattern of vessel involvement demonstrated with MR angiography are essential factors that can suggest the most likely causative mechanism of infarction. This information may have an impact on decisions regarding therapy and the performance of additional diagnostic tests. (orig.)

  7. Probability of causation: Implications for radiological protection and dose limitation

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I.


    This report on the probability of causation of radiation-induced cancer is an attempt to bring together biology, chemistry, physics and statistics to calculate a value in the form of a ratio expressed as a percentage. In involves the interactions of numerous cancer risk factors, and all are fraught with technical difficulties and uncertainties. It is a computational approach to a societal problem that should be resolved in the political arena by men and women of government and law. But, it must be examined, because at the present, we have no reasonable method to explain the complexity of the mechanism of radiation-induced cancer and the probability of injury to an individual exposed in the past to ionizing radiation, and because society does not know how to compensate such a person who may have been injured by radiation, and particularly low-level radiation. Five questions are discussed that concern probability of causation of radiation-induced cancer. First, what is it and how can we best define the concept? Second, what are the methods of estimation and cancer causation? Third, what are the uncertainties involved? Fourth, what are the strengths and limitation of the computational approach? And fifth, what are the implications for radiological protection and dose-limitation?

  8. Probability of causation: Implications for radiological protection and dose limitation

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I.


    This report on the probability of causation of radiation-induced cancer is an attempt to bring together biology, chemistry, physics and statistics to calculate a value in the form of a ratio expressed as a percentage. In involves the interactions of numerous cancer risk factors, and all are fraught with technical difficulties and uncertainties. It is a computational approach to a societal problem that should be resolved in the political arena by men and women of government and law. But, it must be examined, because at the present, we have no reasonable method to explain the complexity of the mechanism of radiation-induced cancer and the probability of injury to an individual exposed in the past to ionizing radiation, and because society does not know how to compensate such a person who may have been injured by radiation, and particularly low-level radiation. Five questions are discussed that concern probability of causation of radiation-induced cancer. First, what is it and how can we best define the concept Second, what are the methods of estimation and cancer causation Third, what are the uncertainties involved Fourth, what are the strengths and limitation of the computational approach And fifth, what are the implications for radiological protection and dose-limitation

  9. Downward Causation and the Neurobiology of Free Will

    CERN Document Server

    Murphy, Nancey; O’Connor, Timothy


    How is free will possible in the light of the physical and chemical underpinnings of brain activity and recent neurobiological experiments? How can the emergence of complexity in hierarchical systems such as the brain, based at the lower levels in physical interactions, lead to something like genuine free will? The nature of our understanding of free will in the light of present-day neuroscience is becoming increasingly important because of remarkable discoveries on the topic being made by neuroscientists at the present time, on the one hand, and its crucial importance for the way we view ourselves as human beings, on the other. A key tool in understanding how free will may arise in this context is the idea of downward causation in complex systems, happening coterminously with bottom up causation, to form an integral whole. Top-down causation is usually neglected, and is therefore emphasized in the other part of the book’s title. The concept is explored in depth, as are the ethical and legal implications of...

  10. The phosphoarginine energy-buffering system of trypanosoma brucei involves multiple arginine kinase isoforms with different subcellular locations.

    Directory of Open Access Journals (Sweden)

    Frank Voncken

    Full Text Available Phosphagen energy-buffering systems play an essential role in regulating the cellular energy homeostasis in periods of high-energy demand or energy supply fluctuations. Here we describe the phosphoarginine/arginine kinase system of the kinetoplastid parasite Trypanosoma brucei, consisting of three highly similar arginine kinase isoforms (TbAK1-3. Immunofluorescence microscopy using myc-tagged protein versions revealed that each isoform is located in a specific subcellular compartment: TbAK1 is exclusively found in the flagellum, TbAK2 in the glycosome, and TbAK3 in the cytosol of T. brucei. The flagellar location of TbAK1 is dependent on a 22 amino acid long N-terminal sequence, which is sufficient for targeting a GFP-fusion protein to the trypanosome flagellum. The glycosomal location of TbAK2 is in agreement with the presence of a conserved peroxisomal targeting signal, the C-terminal tripeptide 'SNL'. TbAK3 lacks any apparent targeting sequences and is accordingly located in the cytosol of the parasite. Northern blot analysis indicated that each TbAK isoform is differentially expressed in bloodstream and procyclic forms of T. brucei, while the total cellular arginine kinase activity was 3-fold higher in bloodstream form trypanosomes. These results suggest a substantial change in the temporal and spatial energy requirements during parasite differentiation. Increased arginine kinase activity improved growth of procyclic form T. brucei during oxidative challenges with hydrogen peroxide. Elimination of the total cellular arginine kinase activity by RNA interference significantly decreased growth (>90% of procyclic form T. brucei under standard culture conditions and was lethal for this life cycle stage in the presence of hydrogen peroxide. The putative physiological roles of the different TbAK isoforms in T. brucei are further discussed.

  11. Genome and phylogenetic analyses of Trypanosoma evansi reveal extensive similarity to T. brucei and multiple independent origins for dyskinetoplasty. (United States)

    Carnes, Jason; Anupama, Atashi; Balmer, Oliver; Jackson, Andrew; Lewis, Michael; Brown, Rob; Cestari, Igor; Desquesnes, Marc; Gendrin, Claire; Hertz-Fowler, Christiane; Imamura, Hideo; Ivens, Alasdair; Kořený, Luděk; Lai, De-Hua; MacLeod, Annette; McDermott, Suzanne M; Merritt, Chris; Monnerat, Severine; Moon, Wonjong; Myler, Peter; Phan, Isabelle; Ramasamy, Gowthaman; Sivam, Dhileep; Lun, Zhao-Rong; Lukeš, Julius; Stuart, Ken; Schnaufer, Achim


    Two key biological features distinguish Trypanosoma evansi from the T. brucei group: independence from the tsetse fly as obligatory vector, and independence from the need for functional mitochondrial DNA (kinetoplast or kDNA). In an effort to better understand the molecular causes and consequences of these differences, we sequenced the genome of an akinetoplastic T. evansi strain from China and compared it to the T. b. brucei reference strain. The annotated T. evansi genome shows extensive similarity to the reference, with 94.9% of the predicted T. b. brucei coding sequences (CDS) having an ortholog in T. evansi, and 94.6% of the non-repetitive orthologs having a nucleotide identity of 95% or greater. Interestingly, several procyclin-associated genes (PAGs) were disrupted or not found in this T. evansi strain, suggesting a selective loss of function in the absence of the insect life-cycle stage. Surprisingly, orthologous sequences were found in T. evansi for all 978 nuclear CDS predicted to represent the mitochondrial proteome in T. brucei, although a small number of these may have lost functionality. Consistent with previous results, the F1FO-ATP synthase γ subunit was found to have an A281 deletion, which is involved in generation of a mitochondrial membrane potential in the absence of kDNA. Candidates for CDS that are absent from the reference genome were identified in supplementary de novo assemblies of T. evansi reads. Phylogenetic analyses show that the sequenced strain belongs to a dominant group of clonal T. evansi strains with worldwide distribution that also includes isolates classified as T. equiperdum. At least three other types of T. evansi or T. equiperdum have emerged independently. Overall, the elucidation of the T. evansi genome sequence reveals extensive similarity of T. brucei and supports the contention that T. evansi should be classified as a subspecies of T. brucei.

  12. Central Nervous System Parasitosis and Neuroinflammation Ameliorated by Systemic IL-10 Administration in Trypanosoma brucei-Infected Mice. (United States)

    Rodgers, Jean; Bradley, Barbara; Kennedy, Peter G E; Sternberg, Jeremy M


    Invasion of the central nervous system (CNS) by African trypanosomes represents a critical step in the development of human African trypanosomiasis. In both clinical cases and experimental mouse infections it has been demonstrated that predisposition to CNS invasion is associated with a type 1 systemic inflammatory response. Using the Trypanosoma brucei brucei GVR35 experimental infection model, we demonstrate that systemic delivery of the counter-inflammatory cytokine IL-10 lowers plasma IFN-γ and TNF-α concentrations, CNS parasitosis and ameliorates neuro-inflammatory pathology and clinical symptoms of disease. The results provide evidence that CNS invasion may be susceptible to immunological attenuation.

  13. Trypanocidal activity of organotin chlorides on Trypanosoma brucei-infected mice

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    Shuaibu M.N.


    Full Text Available The organotin compounds dibulyltin (DBTC and diphenyltin dichlorides (DPTC were tested for trypanocidal activity on a Trypanosoma brucei-infected mice model. At a dose of 10 mg DBTC and 15 mg DPTC/kg/day for five consecutive days, they cleared the parasites from the peripheral blood of the infected mice. Subinoculation of some healthy mice with the homogenates of liver, spleen, kidney, cerebrospinal fluid and blood from the mice considered cured, showed a few cases of relapse. The LD50 of DBTC and DPTC are 90 mg/kg and 75 mg/kg respectively.

  14. A haptoglobin-hemoglobin receptor conveys innate immunity to Trypanosoma brucei in humans

    DEFF Research Database (Denmark)

    Vanhollebeke, Benoit; De Muylder, Géraldine; Nielsen, Marianne J;


    The protozoan parasite Trypanosoma brucei is lysed by apolipoprotein L-I, a component of human high-density lipoprotein (HDL) particles that are also characterized by the presence of haptoglobin-related protein. We report that this process is mediated by a parasite glycoprotein receptor, which...... receptor also recognized the complex between hemoglobin and haptoglobin-related protein, which explains its ability to capture trypanolytic HDLs. Thus, in humans the presence of haptoglobin-related protein has diverted the function of the trypanosome haptoglobin-hemoglobin receptor to elicit innate host...

  15. Zinc finger nuclease technology: A stable tool for high efficiency transformation in bloodstream form T. brucei. (United States)

    Schumann, Gabriela; Kangussu-Marcolino, Monica M; Doiron, Nicholas; Käser, Sandro; de Assis Burle-Caldas, Gabriela; DaRocha, Wanderson D; Teixeira, Santuza M; Roditi, Isabel


    In Trypanosoma brucei, the generation of knockout mutants is relatively easy compared to other organisms as transfection methods are well established. These methods have their limitations, however, when it comes to the generation of genome-wide libraries that require a minimum of several hundred thousand transformants. Double-strand breaks with the meganuclease ISce-I dramatically increase transformation efficiency, but are not widely in use as cell lines need to be generated de novo before each transfection. Here we show that zinc finger nucleases are a robust and stable tool that can enhance transformation in bloodstream forms by more than an order of magnitude.

  16. Structures of aspartate aminotransferases from Trypanosoma brucei, Leishmania major and Giardia lamblia. (United States)

    Abendroth, Jan; Choi, Ryan; Wall, Abigail; Clifton, Matthew C; Lukacs, Christine M; Staker, Bart L; Van Voorhis, Wesley; Myler, Peter; Lorimer, Don D; Edwards, Thomas E


    The structures of three aspartate aminotransferases (AATs) from eukaryotic pathogens were solved within the Seattle Structural Genomics Center for Infectious Disease (SSGCID). Both the open and closed conformations of AAT were observed. Pyridoxal phosphate was bound to the active site via a Schiff base to a conserved lysine. An active-site mutant showed that Trypanosoma brucei AAT still binds pyridoxal phosphate even in the absence of the tethering lysine. The structures highlight the challenges for the structure-based design of inhibitors targeting the active site, while showing options for inhibitor design targeting the N-terminal arm.

  17. Regularity and counterfactuality in Hume's treatment of causation

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    José Oscar de Almeida Marques


    Full Text Available Of the several theories of causation current in our days, Hume is said to be the inspiration of two of the most influential and accepted: the regularity theory, first clearly formulated by Thomas Brown in 1822, and the counterfactual theory, proposed by David Lewis in 1973. After a brief outline of the comparative merits and difficulties of these two views, I proceed to examine whether Hume's own treatment of causation actually corresponds to any of them. I will show that his first definition of cause, coupled with his rules by which to judge about causes and effects, contains elements that, properly developed, allow us to address successfully some traditional difficulties of the regularity view of causation, without resorting to the conceptual resources employed in the counterfactual approach. Therefore, we can properly classify Hume as an advocate of the conception of causation as regularity, noting however that his primary goal in his research and definitions of the concept was to provide not so much an analysis of causation as such, but of causation as we apprehend it, in the form of our ability to make causal inferences and refine them to reach the more sophisticated causal reasonings that are required in the theoretical and practical issues of life.Das diversas teorias da causação existentes em nossos dias, Hume pode ser considerado o precursor de duas das mais influentes e aceitas: a teoria regularista, formulada claramente pela primeira vez por Thomas Brown, em 1822, e a teoria contrafatualista, proposta por David Lewis em 1973. Depois de um breve resumo dos méritos e dificuldades comparativos dessas duas perspectivas, passo a examinar se o tratamento de Hume da causação corresponde, na verdade a algum deles. Mostro que a sua primeira definição de causa, juntamente com suas regras para julgar sobre as causas e efeitos, contém elementos que, devidamente desenvolvidos, permitem-nos abordar com sucesso algumas dificuldades

  18. Models of proximate and ultimate causation in psychology. (United States)

    Alessi, G


    B. F. Skinner saw behavior as a product of three levels of evolution. J. R. Kantor and Gregory Bateson noted similar relations. This article describes and applies basic evolutionary concepts to each level: (a) phylogenic, (b) ontogenic, and (c) cultural evolution. Each level is analyzed in terms of (a) units of selection, (b) variety of units required for the selection process, (c) selection pressures, (d) interactions among levels, and (e) implications for understanding and predicting behavior. Distinguishing between models of proximate and ultimate causation, as in biology, may help clarify research problems posed by, and facilitate better communication among, psychologists.

  19. Bias and Causation Models and Judgment for Valid Comparisons

    CERN Document Server

    Weisberg, Herbert I


    A one-of-a-kind resource on identifying and dealing with bias in statistical research on causal effects. Do cell phones cause cancer? Can a new curriculum increase student achievement? Determining what the real causes of such problems are, and how powerful their effects may be, are central issues in research across various fields of study. Some researchers are highly skeptical of drawing causal conclusions except in tightly controlled randomized experiments, while others discount the threats posed by different sources of bias, even in less rigorous observational studies. Bias and Causation pre

  20. Benzodiazepines and risk of dementia: true association or reverse causation? (United States)

    Barbui, C; Gastaldon, C; Cipriani, A


    According to a recently published population study conducted in France, exposure to benzodiazepines may be associated with an approximately 50% increase in the risk of dementia in the elderly. However, the clinical interpretation of this finding raised some concerns. A causal link between benzodiazepine use and diagnosis of dementia may be real, but it is nevertheless possible that the increased risk might be due to other confounding factors. In this article, the main strengths and weaknesses of this study are briefly analysed, including the possibility of reverse causation. Implications for research and current practice are discussed.

  1. KREX2 is not essential for either procyclic or bloodstream form Trypanosoma brucei.

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    Jason Carnes

    Full Text Available BACKGROUND: Most mitochondrial mRNAs in Trypanosoma brucei require RNA editing for maturation and translation. The edited RNAs primarily encode proteins of the oxidative phosphorylation system. These parasites undergo extensive changes in energy metabolism between the insect and bloodstream stages which are mirrored by alterations in RNA editing. Two U-specific exonucleases, KREX1 and KREX2, are both present in protein complexes (editosomes that catalyze RNA editing but the relative roles of each protein are not known. METHODOLOGY/PRINCIPAL FINDINGS: The requirement for KREX2 for RNA editing in vivo was assessed in both procyclic (insect and bloodstream form parasites by methods that use homologous recombination for gene elimination. These studies resulted in null mutant cells in which both alleles were eliminated. The viability of these cells demonstrates that KREX2 is not essential in either life cycle stage, despite certain defects in RNA editing in vivo. Furthermore, editosomes isolated from KREX2 null cells require KREX1 for in vitro U-specific exonuclease activity. CONCLUSIONS: KREX2 is a U-specific exonuclease that is dispensable for RNA editing in vivo in T. brucei BFs and PFs. This result suggests that the U deletion activity, which is required for RNA editing, is primarily mediated in vivo by KREX1 which is normally found associated with only one type of editosome. The retention of the KREX2 gene implies a non-essential role or a role that is essential in other life cycle stages or conditions.

  2. Analysis of the Trypanosoma brucei cell cycle by quantitative DAPI imaging. (United States)

    Siegel, T Nicolai; Hekstra, Doeke R; Cross, George A M


    Trypanosoma brucei has two DNA compartments: the nucleus and the kinetoplast. DNA replication of these two compartments only partially coincides. Woodward and Gull [Woodward R, Gull K. Timing of nuclear and kinetoplast DNA replication and early morphological events in the cell cycle of Trypanosoma brucei. J Cell Sci 1990;95:49-57] comprehensively studied the relative timing of the replication and segregation of nuclear DNA (nDNA) and kinetoplast DNA (kDNA). Others have since assumed the consistency of morphological indicators of cell-cycle stage among strains and conditions. We report the use of quantitative DAPI imaging to determine the cell-cycle stage of individual procyclic cells. Using this approach, we found that kinetoplast elongation occurs mainly during nuclear S phase and not during G2, as previously assumed. We confirmed this finding by sorting cells by DNA content, followed by fluorescence microscopy. In addition, simultaneous quantitative imaging at two wavelengths can be used to determine the abundance of cell-cycle-regulated proteins during the cell cycle. We demonstrate this technique by co-staining for the non-acetylated state of lysine 4 of histone H4 (H4K4), which is enriched during nuclear S phase.

  3. Investigating the Chaperone Properties of a Novel Heat Shock Protein, Hsp70.c, from Trypanosoma brucei

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    Adélle Burger


    Full Text Available The neglected tropical disease, African Trypanosomiasis, is fatal and has a crippling impact on economic development. Heat shock protein 70 (Hsp70 is an important molecular chaperone that is expressed in response to stress and Hsp40 acts as its co-chaperone. These proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. A novel cytosolic Hsp70, from Trypanosoma brucei, TbHsp70.c, contains an acidic substrate binding domain and lacks the C-terminal EEVD motif. The ability of a cytosolic Hsp40 from Trypanosoma brucei J protein 2, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated. The main objective was to functionally characterize TbHsp70.c to further expand our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed the ability to suppress aggregation of thermolabile MDH and chemically denatured rhodanese. ATPase assays revealed a 2.8-fold stimulation of the ATPase activity of TbHsp70.c by Tbj2. TbHsp70.c and Tbj2 both demonstrated chaperone activity and Tbj2 functions as a co-chaperone of TbHsp70.c. In vivo heat stress experiments indicated upregulation of the expression levels of TbHsp70.c.

  4. Trypanosoma Brucei Aquaglyceroporins Facilitate the Uptake of Arsenite and Antimonite in a pH Dependent Way

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    Néstor L. Uzcátegui


    Full Text Available Background: Trypanosoma brucei is a primitive parasitic protozoan that thrives in diverse environments such as the midgut of the tsetse fly and the blood of a mammalian host. For an adequate adaptation to these environments, the parasite´s aquaglyceroporins play an important role. Methods and Results: In order to test their ability to transport trivalent arsenic and antimony, we expressed the three known Trypanosoma brucei aquaglyceroporins (TbAQPs in the heterologous systems of yeast null aquaporin mutant and Xenopus laevis oocytes. For both expression systems, we found a pH dependent intracellular accumulation of As(III or Sb(III mediated by all of the three TbAQPs, with the exception of TbAQP1-As(III uptake. Additionally, we observed that Trypanosoma brucei aquaglyceroporins allow the passage of As(III in both directions. Conclusion: Taken together, these results demonstrated that T. brucei aquaglyceroporins can serve as entry routes for As(III and Sb(III into the parasitic cell, and that this uptake is pH sensitive. Therefore, aquaporins of protozoan parasites may be considered useful as a vehicle for drug delivery.

  5. Immunospecific immunoglobulins and IL-10 as markers for Trypanosoma brucei rhodesiense late stage disease in experimentally infected vervet monkeys

    DEFF Research Database (Denmark)

    Ngotho, Maina; Kagira, J.M.; Jensen, Henrik Michael Elvang


    OBJECTIVE: To determine the usefulness of IL-10 and immunoglobulin M (IgM) as biomarkers for staging HAT in vervet monkeys, a useful pathogenesis model for humans. METHODS: Vervet monkeys were infected with Trypanosoma brucei rhodesiense and subsequently given sub-curative and curative treatment 28...

  6. Evidence-based toxicology: a comprehensive framework for causation. (United States)

    Guzelian, Philip S; Victoroff, Michael S; Halmes, N Christine; James, Robert C; Guzelian, Christopher P


    This paper identifies deficiencies in some current practices of causation and risk evaluation by toxicologists and formulates an evidence-based solution. The practice of toxicology focuses on adverse health events caused by physical or chemical agents. Some relations between agents and events are identified risks, meaning unwanted events known to occur at some frequency. However, other relations that are only possibilities--not known to occur (and may never be realized)--also are sometimes called risks and are even expressed quantitatively. The seemingly slight differences in connotation among various uses of the word 'risk' conceal deeply philosophic differences in the epistemology of harm. We label as 'nomological possibilities' (not as risks) all predictions of harm that are known not to be physically or logically impossible. Some of these nomological possibilities are known to be causal. We term them 'epistemic'. Epistemic possibilities are risks. The remaining nomological possibilities are called 'uncertainties'. Distinguishing risks (epistemic relationships) from among all nomological possibilities requires knowledge of causation. Causality becomes knowable when scientific experiments demonstrate, in a strong, consistent (repeatable), specific, dose-dependent, coherent, temporal and predictive manner that a change in a stimulus determines an asymmetric, directional change in the effect. Many believe that a similar set of characteristics, popularly called the 'Hill Criteria', make it possible, if knowledge is robust, to infer causation from only observational (nonexperimental) studies, where allocation of test subjects or items is not under the control of the investigator. Until the 1980s, medical decisions about diagnosis, prevention, treatment or harm were often made authoritatively. Rather than employing a rigorous evaluation of causal relationships and applying these criteria to the published knowledge, the field of medicine was dominated by authority

  7. Al Ghazali and Hume on causation and miracles

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    Sedat Yazıcı


    Full Text Available This paper is an attempt to show the similarities and differences between Al Ghazali and Hume on causation and miracles. Such a comparison is interesting because, long before Hume, the issue of necessary causality had been taken up by the Islamic philosophers Al Ghazal in his book The Incoherence the Philosophers. Although Ghazali's and Hume's views on causation are strikingly parallel to one another in their empirical contention, there are still some differences to be noted. First, both reject the view that the connection between causes and effects is of logical necessity. However, to give an ultimate reason for the theory of causality, unlike Hume, Ghazali makes a reference to God. For Hume, we cannot give an ultimate justification for the theory of causality. Second, while Ghazali aimed to reject the necessary causality in order to account for the occurrence of miracles, Hume, on the contrary, used his theory of causality to reject the claim that miracle can occur. In particular, I argue whether Hume's position allows logical possibility of the occurrence of miracle.

  8. Voltage-Gated Channels as Causative Agents for Epilepsies

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    Mutasem Abuhamed


    Full Text Available Problem statement: Epilepsy is a common neurological disorder that afflicts 1-2% of the general population worldwide. It encompasses a variety of disorders with seizures. Approach: Idiopathic epilepsies were defined as a heterogeneous group of seizure disorders that show no underlying cause .Voltage-gated ion channels defect were recognized etiology of epilepsy in the central nervous system. The aim of this article was to provide an update on voltage-gated channels and their mutation as causative agents for epilepsies. We described the structures of the voltage-gated channels, discuss their current genetic studies, and then review the effects of voltage-gated channels as causative agents for epilepsies. Results: Channels control the flow of ions in and out of the cell causing depolarization and hyper polarization of the cell. Voltage-gated channels were classified into four types: Sodium, potassium calcium ands chloride. Voltage-gated channels were macromolecular protein complexes within the lipid membrane. They were divided into subunits. Each subunit had a specific function and was encoded by more than one gen. Conclusion: Current genetic studies of idiopathic epilepsies show the importance of genetic influence on Voltage-gated channels. Different genes may regulate a function in a channel; the channel defect was directly responsible for neuronal hyper excitability and seizures.

  9. Causation and the origin of life. Metabolism or replication first? (United States)

    Pross, Addy


    The conceptual gulf that separates the 'metabolism first' and 'replication first' mechanisms for the emergence of life continues to cloud the origin of life debate. In the present paper we analyze this aspect of the origin of life problem and offer arguments in favor of the 'replication first' school. Utilizing Wicken's two-tier approach to causation we argue that a causal connection between replication and metabolism can only be demonstrated if replication would have preceded metabolism. In conjunction with existing empirical evidence and theoretical reasoning, our analysis concludes that there is no substantive evidence for a 'metabolism first' mechanism for life's emergence, while a coherent case can be made for the 'replication first' group of mechanisms. The analysis reaffirms our conviction that life is an extreme expression of kinetic control, and that the emergence of metabolic pathways can be understood by considering life as a manifestation of 'replicative chemistry'.

  10. Causation entropy from symbolic representations of dynamical systems

    CERN Document Server

    Cafaro, Carlo; Sun, Jie; Bollt, Erik M


    Identification of causal structures and quantification of direct information flows in complex systems is a challenging yet important task, with practical applications in many fields. Data generated by dynamical processes or large-scale systems are often symbolized, either because of the finite resolution of the measurement apparatus, or because of the need of statistical estimation. By algorithmic application of causation entropy, we investigated the effects of symbolization on important concepts such as Markov order and causal structure of the tent map. We uncovered that these quantities depend nonmontonically and, most of all, sensitively on the choice of symbolization. Indeed, we show that Markov order and causal structure do not necessarily converge to their original analog counterparts as the resolution of the partitioning becomes finer.

  11. Phylogeny of Trypanosoma brucei and Trypanosoma evansi in naturally infected cattle in Nigeria by analysis of repetitive and ribosomal DNA sequences. (United States)

    Takeet, Michael I; Peters, Sunday O; Fagbemi, Benjamin O; De Donato, Marcos; Takeet, Vivian O; Wheto, Mathew; Imumorin, Ikhide G


    In continuing efforts to better understand the genetics of bovine trypanosomosis, we assessed genetic diversity of Trypanosoma brucei and Trypanosoma evansi in naturally infected Nigerian cattle using repetitive DNA and internal transcribed spacer 1 of rDNA sequences and compared these sequences to species from other countries. The length of repetitive DNA sequences in both species ranged from 161 to 244 bp and 239 to 240 bp for T. brucei and T. evansi, respectively, while the ITS1 rDNA sequences length range from 299 to 364 bp. The mean GC content of ITS1 rDNA sequences was 33.57 %, and that of repetitive sequences were 39.9 and 31.1 % for T. brucei and T. evansi, respectively. Result from sequence alignment revealed both T. brucei and T. evansi repetitive DNA sequences to be more polymorphic than ITS1 rDNA sequences, with moderate points of deletion and insertions. T. brucei separated into two clades when subjected to phylogenetic analysis. T. evansi repetitive DNA sequences clustered tightly within the T. brucei clade while the ITS1 rDNA sequences of T. brucei were clearly separated from T. theileri and T. vivax individually used as outgroups. This study suggest that ITS1 rDNA sequences may not be suitable for phylogenetic differentiation of the Trypanozoon group and also suggest that T. evansi may be a phenotypic variant of T. brucei which may have potential implications in designing prevention and therapeutic strategies.

  12. The contribution of chromosomal translocations to antigenic variation in Trypanosoma brucei. (United States)

    Van der Ploeg, L H; Cornelissen, A W


    Genomic rearrangements influencing gene expression occur throughout nature. Several of these rearrangements disrupt normal gene expression, as exemplified by the genetic alterations caused by the mobile genetic elements of maize or Drosophila (see Shapiro 1983). Other rearrangements are part of the normal developmental programme of an organism. An understanding of the control of genomic rearrangements and their effects on gene expression should contribute to our insight into the mechanism of genetic programming and cellular development. The protozoan parasite Trypanosoma brucei exhibits a variety of genomic rearrangements that influence the expression of genes that code for versions of the variant surface glycoprotein (v.s.g.), which makes up the cell surface coat. V.s.g. genes are expressed in a mutually exclusive manner. Several v.s.g. genes are activated by duplicative transposition of the gene to a telomeric expression site where they are transcribed, while others can be activated without detectable genomic rearrangements. Recently we have been able to fractionate the chromosomes of T. brucei in agarose gels (Van der Ploeg et al. 1984 a). This led to the observations that duplicative transpositions occur inter-chromosomally and that the chromosomes of T. brucei are subject to frequent recombinations that displace hundreds of kilobase pairs. At least two and possibly more telomeric expression sites can be used for v.s.g. gene transcription. How these sites are activated and inactivated is still unsolved, but this does not depend on recombinations in the vicinity of the gene. Gross genomic rearrangements occur sometimes in correlation with antigenic switching and this suggests that such rearrangements have a function in regulating the mutually exclusive transcription of the different expression sites. V.s.g. genes consist of two exons. No physical linkage of the 35 nucleotide (n.t.) mini-exon to the v.s.g. gene main exon occurred within 15 kilobase pairs in

  13. Mapping replication dynamics in Trypanosoma brucei reveals a link with telomere transcription and antigenic variation. (United States)

    Devlin, Rebecca; Marques, Catarina A; Paape, Daniel; Prorocic, Marko; Zurita-Leal, Andrea C; Campbell, Samantha J; Lapsley, Craig; Dickens, Nicholas; McCulloch, Richard


    Survival of Trypanosoma brucei depends upon switches in its protective Variant Surface Glycoprotein (VSG) coat by antigenic variation. VSG switching occurs by frequent homologous recombination, which is thought to require locus-specific initiation. Here, we show that a RecQ helicase, RECQ2, acts to repair DNA breaks, including in the telomeric site of VSG expression. Despite this, RECQ2 loss does not impair antigenic variation, but causes increased VSG switching by recombination, arguing against models for VSG switch initiation through direct generation of a DNA double strand break (DSB). Indeed, we show DSBs inefficiently direct recombination in the VSG expression site. By mapping genome replication dynamics, we reveal that the transcribed VSG expression site is the only telomeric site that is early replicating - a differential timing only seen in mammal-infective parasites. Specific association between VSG transcription and replication timing reveals a model for antigenic variation based on replication-derived DNA fragility.

  14. Sec16 determines the size and functioning of the Golgi in the protist parasite, Trypanosoma brucei. (United States)

    Sealey-Cardona, Marco; Schmidt, Katy; Demmel, Lars; Hirschmugl, Tatjana; Gesell, Tanja; Dong, Gang; Warren, Graham


    The Sec16 homologue in Trypanosoma brucei has been identified and characterized. TbSec16 colocalizes with COPII components at the single endoplasmic reticulum exit site (ERES), which is next to the single Golgi stack in the insect (procyclic) form of this organism. Depletion of TbSec16 reduces the size of the ERES and the Golgi, and slows growth and transport of a secretory marker to the cell surface; conversely, overexpression of TbSec16 increases the size of the ERES and Golgi but has no effect on growth or secretion. Together these data suggest that TbSec16 regulates the size of the ERES and Golgi and this size is set for optimal growth of the organism.

  15. Trypanosoma brucei Parasites Occupy and Functionally Adapt to the Adipose Tissue in Mice


    Trindade, Sandra; Rijo-Ferreira, Filipa; Carvalho, Tânia; Pinto-Neves, Daniel; Guegan, Fabien; Aresta-Branco, Francisco; Bento, Fabio; Young, Simon A.; Pinto, Andreia; Van Den Abbeele, Jan; Ribeiro, Ruy M.; Dias, Sérgio; Smith, Terry K.; Figueiredo, Luisa M.


    This work was supported by 55007419 (HHMI) and 2151 (EMBO) to L.M.F., D.P.-N., F.B., and F.G.; FCT fellowships to S.T., F.R.-F., and F.A.-B. (SFRH/BPD/89833/2012, SFRH/BD/51286/2010, and SFRH/BD/80718/2011, respectively); Wellcome Trust grant (093228), MRC MR/M020118/1, and European Community Seventh Framework Programme under grant agreement No. 602773 (Project KINDRED) to S.A.Y. and T.K.S.; and PAI 7/41 (Belspo) and ERC-NANOSYM to J.V.D.A. Trypanosoma brucei is an extracellular parasite t...

  16. Contribution of Glucose Transport to the Control of the Glycolytic Flux in Trypanosoma brucei (United States)

    Bakker, Barbara M.; Walsh, Michael C.; Ter Kuile, Benno H.; Mensonides, Femke I. C.; Michels, Paul A. M.; Opperdoes, Fred R.; Westerhoff, Hans V.


    The rate of glucose transport across the plasma membrane of the bloodstream form of Trypanosoma brucei was modulated by titration of the hexose transporter with the inhibitor phloretin, and the effect on the glycolytic flux was measured. A rapid glucose uptake assay was developed to measure the transport activity independently of the glycolytic flux. Phloretin proved a competitive inhibitor. When the effect of the intracellular glucose concentration on the inhibition was taken into account, the flux control coefficient of the glucose transporter was between 0.3 and 0.5 at 5 mM glucose. Because the flux control coefficients of all steps in a metabolic pathway sum to 1, this result proves that glucose transport is not the rate-limiting step of trypanosome glycolysis. Under physiological conditions, transport shares the control with other steps. At glucose concentrations much lower than physiological, the glucose carrier assumed all control, in close agreement with model predictions.

  17. Population genetics of Trypanosoma brucei rhodesiense: clonality and diversity within and between foci.

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    Craig W Duffy


    Full Text Available African trypanosomes are unusual among pathogenic protozoa in that they can undergo their complete morphological life cycle in the tsetse fly vector with mating as a non-obligatory part of this development. Trypanosoma brucei rhodesiense, which infects humans and livestock in East and Southern Africa, has classically been described as a host-range variant of the non-human infective Trypanosoma brucei that occurs as stable clonal lineages. We have examined T. b. rhodesiense populations from East (Uganda and Southern (Malawi Africa using a panel of microsatellite markers, incorporating both spatial and temporal analyses. Our data demonstrate that Ugandan T. b. rhodesiense existed as clonal populations, with a small number of highly related genotypes and substantial linkage disequilibrium between pairs of loci. However, these populations were not stable as the dominant genotypes changed and the genetic diversity also reduced over time. Thus these populations do not conform to one of the criteria for strict clonality, namely stability of predominant genotypes over time, and our results show that, in a period in the mid 1990s, the previously predominant genotypes were not detected but were replaced by a novel clonal population with limited genetic relationship to the original population present between 1970 and 1990. In contrast, the Malawi T. b. rhodesiense population demonstrated significantly greater diversity and evidence for frequent genetic exchange. Therefore, the population genetics of T. b. rhodesiense is more complex than previously described. This has important implications for the spread of the single copy T. b. rhodesiense gene that allows human infectivity, and therefore the epidemiology of the human disease, as well as suggesting that these parasites represent an important organism to study the influence of optional recombination upon population genetic dynamics.

  18. Knockdown of Inner Arm Protein IC138 in Trypanosoma brucei Causes Defective Motility and Flagellar Detachment.

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    Corinne S Wilson

    Full Text Available Motility in the protozoan parasite Trypanosoma brucei is conferred by a single flagellum, attached alongside the cell, which moves the cell forward using a beat that is generated from tip-to-base. We are interested in characterizing components that regulate flagellar beating, in this study we extend the characterization of TbIC138, the ortholog of a dynein intermediate chain that regulates axonemal inner arm dynein f/I1. TbIC138 was tagged In situ-and shown to fractionate with the inner arm components of the flagellum. RNAi knockdown of TbIC138 resulted in significantly reduced protein levels, mild growth defect and significant motility defects. These cells tended to cluster, exhibited slow and abnormal motility and some cells had partially or fully detached flagella. Slight but significant increases were observed in the incidence of mis-localized or missing kinetoplasts. To document development of the TbIC138 knockdown phenotype over time, we performed a detailed analysis of flagellar detachment and motility changes over 108 hours following induction of RNAi. Abnormal motility, such as slow twitching or irregular beating, was observed early, and became progressively more severe such that by 72 hours-post-induction, approximately 80% of the cells were immotile. Progressively more cells exhibited flagellar detachment over time, but this phenotype was not as prevalent as immotility, affecting less than 60% of the population. Detached flagella had abnormal beating, but abnormal beating was also observed in cells with no flagellar detachment, suggesting that TbIC138 has a direct, or primary, effect on the flagellar beat, whereas detachment is a secondary phenotype of TbIC138 knockdown. Our results are consistent with the role of TbIC138 as a regulator of motility, and has a phenotype amenable to more extensive structure-function analyses to further elucidate its role in the control of flagellar beat in T. brucei.

  19. Secondary Metabolites from Vietnamese Marine Invertebrates with Activity against Trypanosoma brucei and T. cruzi

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    Nguyen Phuong Thao


    Full Text Available Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50 < 5.0 μg/mL. Among the compounds isolated from these extracts, laevigatol B (1 from Lobophytum crassum and L. laevigatum, (24S-ergost-4-ene-3-one (2 from Sinularia dissecta, astropectenol A (3 from Astropecten polyacanthus, and cholest-8-ene-3β,5α,6β,7α-tetraol (4 from Diadema savignyi showed inhibitory activity against T. brucei with EC50 values ranging from 1.57 ± 0.14 to 14.6 ± 1.36 μM, relative to the positive control, pentamidine (EC50 = 0.015 ± 0.003 μM. Laevigatol B (1 and 5α-cholest-8(14-ene-3β,7α-diol (5 exhibited also significant inhibitory effects on T. cruzi. The cytotoxic activity of the pure compounds on mammalian cells was also assessed and found to be insignificant in all cases. This is the first report on the inhibitory effects of marine organisms collected in Vietnamese seas against Trypanosoma species responsible for neglected tropical diseases.

  20. Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei

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    Gualdrón-López, Melisa [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium); Michels, Paul A.M., E-mail: [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium)


    Highlights: ► Most eukaryotic cells have a single gene for the peroxin PEX5. ► PEX5 is sensitive to in vitro proteolysis in distantly related organisms. ► TbPEX5 undergoes N-terminal truncation in vitro and possibly in vivo. ► Truncated TbPEX5 is still capable of binding PTS1-containing proteins. ► PEX5 truncation is physiologically relevant or an evolutionary conserved artifact. -- Abstract: Glycolysis in kinetoplastid protists such as Trypanosoma brucei is compartmentalized in peroxisome-like organelles called glycosomes. Glycosomal matrix-protein import involves a cytosolic receptor, PEX5, which recognizes the peroxisomal-targeting signal type 1 (PTS1) present at the C-terminus of the majority of matrix proteins. PEX5 appears generally susceptible to in vitro proteolytic processing. On western blots of T. brucei, two PEX5 forms are detected with apparent M{sub r} of 100 kDa and 72 kDa. 5′-RACE-PCR showed that TbPEX5 is encoded by a unique transcript that can be translated into a protein of maximally 72 kDa. However, recombinant PEX5 migrates aberrantly in SDS–PAGE with an apparent M{sub r} of 100 kDa, similarly as observed for the native peroxin. In vitro protease susceptibility analysis of native and {sup 35}S-labelled PEX5 showed truncation of the 100 kDa form at the N-terminal side by unknown parasite proteases, giving rise to the 72 kDa form which remains functional for PTS1 binding. The relevance of these observations is discussed.

  1. No gold standard estimation of the sensitivity and specificity of two molecular diagnostic protocols for Trypanosoma brucei spp. in Western Kenya.

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    Barend Mark de Clare Bronsvoort

    Full Text Available African animal trypanosomiasis is caused by a range of tsetse transmitted protozoan parasites includingTrypanosoma vivax, Trypanosoma congolense and Trypansoma brucei. In Western Kenya and other parts of East Africa two subspecies of T. brucei, T.b. brucei and the zoonoticT.b. rhodesiense, co-circulate in livestock. A range of polymerase chain reactions (PCR have been developed as important molecular diagnostic tools for epidemiological investigations of T. brucei s.l. in the animal reservoir and of its zoonotic potential. Quantification of the relative performance of different diagnostic PCRs is essential to ensure comparability of studies. This paper describes an evaluation of two diagnostic test systems for T. brucei using a T. brucei s.l. specific PCR [1] and a single nested PCR targeting the Internal Transcribed Spacer (ITS regions of trypanosome ribosomal DNA [2]. A Bayesian formulation of the Hui-Walter latent class model was employed to estimate their test performance in the absence of a gold standard test for detecting T.brucei s.l. infections in ear-vein blood samples from cattle, pig, sheep and goat populations in Western Kenya, stored on Whatman FTA cards. The results indicate that the system employing the T. brucei s.l. specific PCR (Se1=0.760 had a higher sensitivity than the ITS-PCR (Se2=0.640; both have high specificity (Sp1=0.998; Sp2=0.997. The true prevalences for livestock populations were estimated (pcattle=0.091, ppigs=0.066, pgoats=0.005, psheep=0.006, taking into account the uncertainties in the specificity and sensitivity of the two test systems. Implications of test performance include the required survey sample size; due to its higher sensitivity and specificity, the T. brucei s.l. specific PCR requires a consistently smaller sample size than the ITS-PCR for the detection of T. brucei s.l. However the ITS-PCR is able to simultaneously screen samples for other pathogenic trypanosomes and may thus be, overall, a better

  2. Prediction of causative genomic relationships using sequence data of five French and Danish dairy cattle breeds

    DEFF Research Database (Denmark)

    van den Berg, Irene; Boichard, Didier; Lund, Mogens Sandø

    and HD chips, or two 1 Kb intervals on both sides of each causative mutation, varying the distance between causative mutations and intervals from 1 base to 1 Mb. Subsequently, the regression coefficient of the genomic relationships at prediction markers on the genomic relationships at causal loci...... data is more likely to contain causative mutations and therefore increase the prediction accuracy in such populations. We studied the potential advantage of using real sequence data for prediction of genomic relationships at causative mutations using sequence data of chromosome 1 for 122 Holstein, 27...

  3. Scanning and three-dimensional electron microscopy methods for the study of Trypanosoma brucei and Leishmania mexicana flagella. (United States)

    Gluenz, Eva; Wheeler, Richard John; Hughes, Louise; Vaughan, Sue


    Three-dimensional electron microscopy tools have revolutionized our understanding of cell structure and molecular complexes in biology. Here, we describe methods for studying flagellar ultrastructure and biogenesis in two unicellular parasites-Trypanosoma brucei and Leishmania mexicana. We describe methods for the preparation of these parasites for scanning electron microscopy cellular electron tomography, and serial block face scanning electron microscopy (SBFSEM). These parasites have a highly ordered cell shape and form, with a defined positioning of internal cytoskeletal structures and organelles. We show how knowledge of these can be used to dissect cell cycles in both parasites and identify the old flagellum from the new in T. brucei. Finally, we demonstrate the use of SBFSEM three-dimensional models for analysis of individual whole cells, demonstrating the excellent potential this technique has for future studies of mutant cell lines.

  4. Inhibitors of the mitochondrial cytochrome b-c1 complex inhibit the cyanide-insensitive respiration of Trypanosoma brucei. (United States)

    Turrens, J F; Bickar, D; Lehninger, A L


    The cyanide-insensitive respiration of bloodstream trypomastigote forms of Trypanosoma brucei (75 +/- 8 nmol O2 min-1(mg protein)-1) is completely inhibited by the mitochondrial ubiquinone-like inhibitors 2-hydroxy-3-undecyl-1,4-naphthoquinone (UHNQ) and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT). The Ki values for UHDBT (30 nM) and UHNQ (2 microM) are much lower than the reported Ki for salicylhydroxamic acid (SHAM) (5 microM), a widely used inhibitor of the cyanide-insensitive oxidase. UHNQ also stimulated the glycerol-3-phosphate-dependent reduction of phenazine methosulfate, demonstrating that the site of UHNQ inhibition is on the terminal oxidase of the cyanide-insensitive respiration of T. brucei. These results suggest that a ubiquinone-like compound may act as an electron carrier between the two enzymatic components of the cyanide-insensitive glycerol-3-phosphate oxidase.

  5. TbFlabarin, a flagellar protein of Trypanosoma brucei, highlights differences between Leishmania and Trypanosoma flagellar-targeting signals. (United States)

    Tetaud, Emmanuel; Lefebvre, Michèle; M'Bang-Benet, Diane-Ethna; Crobu, Lucien; Blancard, Corinne; Sterkers, Yvon; Pages, Michel; Bastien, Patrick; Merlin, Gilles


    TbFlabarin is the Trypanosoma brucei orthologue of the Leishmania flagellar protein LdFlabarin but its sequence is 33% shorter than LdFlabarin, as it lacks a C-terminal domain that is indispensable for LdFlabarin to localize to the Leishmania flagellum. TbFlabarin is mainly expressed in the procyclic forms of the parasite and localized to the flagellum, but only when two palmitoylable cysteines at positions 3 and 4 are present. TbFlabarin is more strongly attached to the membrane fraction than its Leishmania counterpart, as it resists complete solubilization with as much as 0.5% NP-40. Expression ablation by RNA interference did not change parasite growth in culture, its morphology or apparent motility. Heterologous expression showed that neither TbFlabarin in L. amazonensis nor LdFlabarin in T. brucei localized to the flagellum, revealing non-cross-reacting targeting signals between the two species.

  6. Causative constructions in Woirata, Kisar Island (Southwest Maluku, Indonesia

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    N. Nazarudin


    Full Text Available Woirata (or Oirata, see Van Engelenhoven in this volume is closely related to Fataluku (Timor-Leste and belongs to the Timor-Leste subgroup of the Timor-Alor-Pantar language family (TAP together with Makalero and Makasai (Schapper, Huber, and Van Engelenhoven 2012. It has about 1,566 speakers. Taber (1993 suggests that there are 24 languages in Southwest Maluku of which 23 are Austronesian; Woirata is the only non-Austronesian language in the area. It is interesting to research in how far Woirata has been influenced by Austronesian languages. Because the Woirata and other people who live on Kisar Island, like the Meher, are using Melayu Tenggara Jauh (MTJ as their lingua franca, one may expect deep language contact between Woirata and MTJ. This multilingual situation suggests a contact induced language change of Woirata, imposed by MTJ. This contribution aims to describe the causative constructions in Woirata and compare them with the counterpart constructions in MTJ and Meher.

  7. An overview of fruit allergy and the causative allergens. (United States)

    Hassan, A K G; Venkatesh, Y P


    Plant allergens, being one of the most widespread allergenic substances, are hard to avoid. Hence, their identification and characterization are of prime importance for the diagnosis and treatment of food allergy. The reported allergies to fruits mainly evoke oral allergy syndrome caused by the presence of cross-reactive IgE to certain pollens and thus, allergy to fruits has also been linked to particular pollens. Many fruit allergies are being studied for their causative allergens, and are being characterized. Some tropical or exotic fruits are responsible for region-specific allergies for which only limited information is available, and generally lack allergen characterization. From a survey of the literature on fruit allergy, it is clear that some common fruits (apple, peach, musk melon, kiwi fruit, cherry, grape, strawberry, banana, custard apple, mango and pomegranate) and their allergens appear to be at the center of current research on food allergy. The present review focuses on common fruits reported as allergenic and their identified allergens; a brief description of allergens from six rare/tropical fruits is also covered.

  8. Inferring causative variants in microRNA target sites. (United States)

    Thomas, Laurent F; Saito, Takaya; Sætrom, Pål


    MicroRNAs (miRNAs) regulate genes post transcription by pairing with messenger RNA (mRNA). Variants such as single nucleotide polymorphisms (SNPs) in miRNA regulatory regions might result in altered protein levels and disease. Genome-wide association studies (GWAS) aim at identifying genomic regions that contain variants associated with disease, but lack tools for finding causative variants. We present a computational tool that can help identifying SNPs associated with diseases, by focusing on SNPs affecting miRNA-regulation of genes. The tool predicts the effects of SNPs in miRNA target sites and uses linkage disequilibrium to map these miRNA-related variants to SNPs of interest in GWAS. We compared our predicted SNP effects in miRNA target sites with measured SNP effects from allelic imbalance sequencing. Our predictions fit measured effects better than effects based on differences in free energy or differences of TargetScan context scores. We also used our tool to analyse data from published breast cancer and Parkinson's disease GWAS and significant trait-associated SNPs from the NHGRI GWAS Catalog. A database of predicted SNP effects is available at The database is based on haplotype data from the CEU HapMap population and miRNAs from miRBase 16.0.


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    Full Text Available Excessive consumption of fluoride leads to toxic manifestations in man, collectively referred to as Fluorosis. Latest estimates suggest that around 200 million people from among 25 nations the world over, are under the dreadful fate of Fluorosis. In India, 20 states are under fluoride attack. OBJECTIVES: To study the prevalence and causative factors of dental fluorosis among children in the age group of 10-15 years in Kerala. METHODOLOGY: Two endemic districts and two neighboring non endemic districts were selected for this study. Sample size of 980 was calculated and adequate sample was selected from the school going children. A pretested modified questionnaire was used to collect the data. The fluorosis status was assessed by dental specialists. The information regarding the fluoride content of the water was also obtained. The data was entered and analyzed. The prevalence of fluorosis was calculated in percentages. RESULTS: The prevalence of dental fluorosis in the endemic districts of Alappuzha and Palakkad were 37.4% and 39.2% respectively. The prevalence in the neighboring non endemic districts of Kollam and Thrissur were 4.4 % and 2.2% respectively. The community fluorosis index was 0.61 in Alappuzha and 0.63 in Palakkad. The prevalence was higher among boys than among girls

  10. Comparative genomics reveals two novel RNAi factors in Trypanosoma brucei and provides insight into the core machinery.

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    Rebecca L Barnes

    Full Text Available The introduction ten years ago of RNA interference (RNAi as a tool for molecular exploration in Trypanosoma brucei has led to a surge in our understanding of the pathogenesis and biology of this human parasite. In particular, a genome-wide RNAi screen has recently been combined with next-generation Illumina sequencing to expose catalogues of genes associated with loss of fitness in distinct developmental stages. At present, this technology is restricted to RNAi-positive protozoan parasites, which excludes T. cruzi, Leishmania major, and Plasmodium falciparum. Therefore, elucidating the mechanism of RNAi and identifying the essential components of the pathway is fundamental for improving RNAi efficiency in T. brucei and for transferring the RNAi tool to RNAi-deficient pathogens. Here we used comparative genomics of RNAi-positive and -negative trypanosomatid protozoans to identify the repertoire of factors in T. brucei. In addition to the previously characterized Argonaute 1 (AGO1 protein and the cytoplasmic and nuclear Dicers, TbDCL1 and TbDCL2, respectively, we identified the RNA Interference Factors 4 and 5 (TbRIF4 and TbRIF5. TbRIF4 is a 3'-5' exonuclease of the DnaQ superfamily and plays a critical role in the conversion of duplex siRNAs to the single-stranded form, thus generating a TbAGO1-siRNA complex required for target-specific cleavage. TbRIF5 is essential for cytoplasmic RNAi and appears to act as a TbDCL1 cofactor. The availability of the core RNAi machinery in T. brucei provides a platform to gain mechanistic insights in this ancient eukaryote and to identify the minimal set of components required to reconstitute RNAi in RNAi-deficient parasites.

  11. T. brucei infection reduces B lymphopoiesis in bone marrow and truncates compensatory splenic lymphopoiesis through transitional B-cell apoptosis.

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    Viki Bockstal


    Full Text Available African trypanosomes of the Trypanosoma brucei species are extracellular protozoan parasites that cause the deadly disease African trypanosomiasis in humans and contribute to the animal counterpart, Nagana. Trypanosome clearance from the bloodstream is mediated by antibodies specific for their Variant Surface Glycoprotein (VSG coat antigens. However, T. brucei infection induces polyclonal B cell activation, B cell clonal exhaustion, sustained depletion of mature splenic Marginal Zone B (MZB and Follicular B (FoB cells, and destruction of the B-cell memory compartment. To determine how trypanosome infection compromises the humoral immune defense system we used a C57BL/6 T. brucei AnTat 1.1 mouse model and multicolor flow cytometry to document B cell development and maturation during infection. Our results show a more than 95% reduction in B cell precursor numbers from the CLP, pre-pro-B, pro-B, pre-B and immature B cell stages in the bone marrow. In the spleen, T. brucei induces extramedullary B lymphopoiesis as evidenced by significant increases in HSC-LMPP, CLP, pre-pro-B, pro-B and pre-B cell populations. However, final B cell maturation is abrogated by infection-induced apoptosis of transitional B cells of both the T1 and T2 populations which is not uniquely dependent on TNF-, Fas-, or prostaglandin-dependent death pathways. Results obtained from ex vivo co-cultures of living bloodstream form trypanosomes and splenocytes demonstrate that trypanosome surface coat-dependent contact with T1/2 B cells triggers their deletion. We conclude that infection-induced and possibly parasite-contact dependent deletion of transitional B cells prevents replenishment of mature B cell compartments during infection thus contributing to a loss of the host's capacity to sustain antibody responses against recurring parasitemic waves.

  12. Trypanosoma brucei rhodesiense infection in a German traveller returning from the Masai Mara area, Kenya, January 2012. (United States)

    Wolf, T; Wichelhaus, T; Gottig, S; Kleine, C; Brodt, H R; Just-Nuebling, G


    In January 2012, a case of Human African Trypanosomiasis (HAT) has been identified in Germany in a traveller returning from the Masai Mara area in Kenya. The 62-year-old man had travelled to the Masai Mara game park from 18 to 19 January 2012 and developed fever on 28 January. The infection with Trypanosoma brucei rhodesiense was confirmed by laboratory testing three days hereafter.

  13. A target-based high throughput screen yields Trypanosoma brucei hexokinase small molecule inhibitors with antiparasitic activity.

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    Elizabeth R Sharlow

    Full Text Available BACKGROUND: The parasitic protozoan Trypanosoma brucei utilizes glycolysis exclusively for ATP production during infection of the mammalian host. The first step in this metabolic pathway is mediated by hexokinase (TbHK, an enzyme essential to the parasite that transfers the gamma-phospho of ATP to a hexose. Here we describe the identification and confirmation of novel small molecule inhibitors of bacterially expressed TbHK1, one of two TbHKs expressed by T. brucei, using a high throughput screening assay. METHODOLOGY/PRINCIPAL FINDINGS: Exploiting optimized high throughput screening assay procedures, we interrogated 220,233 unique compounds and identified 239 active compounds from which ten small molecules were further characterized. Computation chemical cluster analyses indicated that six compounds were structurally related while the remaining four compounds were classified as unrelated or singletons. All ten compounds were approximately 20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03brucei parasites, Leishmania promastigotes, and mammalian cell lines. Analysis of two structurally related compounds, ebselen and SID 17387000, revealed that both were mixed inhibitors of TbHK1 with respect to ATP. Additionally, both compounds inhibited parasite lysate-derived HK activity. None of the compounds displayed structural similarity to known hexokinase inhibitors or human African trypanosomiasis therapeutics. CONCLUSIONS/SIGNIFICANCE: The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome.

  14. Evolutionary consequences of a large duplication event in Trypanosoma brucei: Chromosomes 4 and 8 are partial duplicons

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    Jackson Andrew P


    Full Text Available Abstract Background Gene order along the genome sequence of the human parasite Trypanosoma brucei provides evidence for a 0.5 Mb duplication, comprising the 3' regions of chromosomes 4 and 8. Here, the principal aim was to examine the contribution made by this duplication event to the T. brucei genome sequence, emphasising the consequences for gene content and the evolutionary change subsequently experienced by paralogous gene copies. The duplicated region may be browsed online at Results Comparisons of trypanosomatid genomes demonstrated widespread gene loss from each duplicon, but also showed that 47% of duplicated genes were retained on both chromosomes as paralogous loci. Secreted and surface-expressed genes were over-represented among retained paralogs, reflecting a bias towards important factors at the host-parasite interface, and consistent with a dosage-balance hypothesis. Genetic divergence in both coding and regulatory regions of retained paralogs was bimodal, with a deficit in moderately divergent paralogs; in particular, non-coding sequences were either conserved or entirely remodelled. The conserved paralogs included examples of remarkable sequence conservation, but also considerable divergence of both coding and regulatory regions. Sequence divergence typically displayed strong negative selection; but several features, such as asymmetric evolutionary rates, positively-selected codons and other non-neutral substitutions, suggested that divergence of some paralogs was driven by functional change. The absence of orthologs to retained paralogs in T. congolense indicated that the duplication event was specific to T. brucei. Conclusion The duplication of this chromosomal region doubled the dosage of many genes. Rather than creating 'more of the same', these results show that paralogs were structurally modified according to various evolutionary trajectories. The retention of paralogs, and

  15. Chemopreventive effect of methanolic extract of Azadirachta indica on experimental Trypanosoma brucei induced oxidative stress in dogs

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    Temidayo O Omobowale


    Full Text Available Introduction: The medicinal properties of Azadirachta indica have been harnessed for many years in the treatment of many diseases in both humans and animals. Materials and Methods: Twenty-five apparently healthy dogs weighing between 3 and 8 kg were randomly divided into five groups with five dogs in each group. Ameliorative effect of A. indica on erythrocyte antioxidant status and markers of oxidative stress were assessed. Liver and kidney function tests were also performed. Results: Pre-treatment with methanolic extract of Azadirachta indica (MEAI at different doses did not significantly alter the values of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activity in Trypanosoma brucei infection. Although, serum creatinine significantly (P 0.05 difference compared to the values obtained in pre-treated animals. Pre-treatment with 100 mg/kg and 200 mg/kg of A. indica significantly (P < 0.05 decreased serum myeloperoxidase activity at 2 weeks post-infection with T. brucei. Conclusion: From this study, MEAI showed significant ability to attenuate oxidative stress and inflammation during experimental T. brucei infection.


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    Katsapov D.V.


    Full Text Available Introduction. Increased level of morbidity of infective endocarditis (IE connected with new risk factors: intravenous drug use, cardiosurgical interventions, hemodialysis brought new clinical forms of the disease. As it shown in a literature main pathogenetic factors of IE are bacteraemia, trauma of endocardium and invasive medical procedures. Very typical pathogens are streptococci and staphylococci. Most typically mitral and aortal valves are affected with spreading of vegetations on surrounding media. Discussion. IE is polyetiologic disease caused by more than 128 microorganisms, and still a challenge for medical professionals. Detection a causative agent is critical for proper specific treatment. In different sources data on percentage of proven cases very according to country and different medical centres reflecting different local epidemiology of IE, diagnostic criteria and protocols. Culture negative infectious endocarditis (CNIE is considered in case of obtaining of three negative results of cultivation of samples on a standard blood agar during 7 days and subculturing. CNIE incidence very form 2% to 33% according to different researches and higher in cases of community acquired infection and reseeding antibacterial treatment. Some of cases of CNIE caused by gram - negative fastidious microorganisms - Haemophilus parainfluenzae, Actinobacillus, Actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae, with united in HACEK group according to their properties to colonize oropharynx and requirement in special conditions and duration of incubation. Detection of some intracellular bacteria, such as C. burnetti and Bartonella spp. require immunological methods of detection, histological methods and of PCR. Conclusion. In case of diagnostics of patients with CNIE it is necessary to use a combination of prolonged subculturing of serum, emboli and histologic material on blood agar with microscopy by Warthin

  17. Entropy and Information Transmission in Causation and Retrocausation (United States)

    Moddel, Garret


    Although experimental evidence for retrocausation exists, there are clearly subtleties to the phenomenon. The bilking paradox, in which one intervenes to eliminate a subsequent cause after a preceding effect has occurred, appears on the surface to show that retrocausation is logically impossible. In a previous paper, the second law of thermodynamics was invoked to show that the entropy in each process of a psi interaction (presentience, telepathy, remote perception, and psychokinesis) cannot decrease, prohibiting psi processes in which signals condense from background fluctuations. Here it is shown, perhaps contrary to one's intuition, that reversible processes cannot be influenced through retrocausation, but irreversible processes can. The increase in thermodynamic entropy in irreversible processes — which are generally described by Newtonian mechanics but not Lagrangian dynamics and Hamilton's Principle — is required for causation. Thermodynamically reversible processes cannot be causal and hence also cannot be retrocausal. The role of entropy in psi interactions is extended by using the bilking paradox to consider information transmission in retroactive psychokinesis (PK). PK efficiency, ηPK, is defined. A prediction of the analysis is that ηPK ⩽ H/H0, where H is the information uncertainty or entropy in the retro-PK agent's knowledge of the event that is to be influenced retrocausally. The information entropy can provide the necessary ingredient for non-reversibility, and hence retrocausation. Noise and bandwidth limitations in the communication to the agent of the outcome of the event increase the maximum PK efficiency. Avoidance of the bilking paradox does not bar a subject from using the premonition of an event to prevent it from occurring. The necessity for large information entropy, which is the expected value of the surprisal, is likely to be essential for any successful PK process, not just retro-PK processes. Hence uncertainty in the

  18. Mycetoma in Iran: Causative agents and geographic distribution

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    Shahindokht Bassiri-Jahromi


    Full Text Available Background: Mycetoma is a chronic granulomatous disease caused by true fungi (eumycetoma or filamentous bacteria (actinomycetoma. It usually involves the subcutaneous tissue after a traumatic inoculation of the causative organism. We reviewed retrospectively 13 patients with mycetoma. Materials and Methods: This study reports the etiologic agents and distribution of mycetoma in 35 cases from 1994 to2009 in Iran. The diagnostic of mycetoma were confirmed by histopathology and direct preparation, culture techniques, and histopathology of granules and surgical biopsies, radiological examination of the affected site. Results: Mycetoma was identified in 35 patients of 168 suspected patients (20.8%. They occurred in 22 male and 13 females. Their ages ranged from 14 to 80 years. The duration of the disease ranged from two months to 38 years. Sixteen patients had eumycetoma, and 19 patients had actinomycetoma, one of them had mix infections by eumycetoma and actinomycetoma. The majority of the patients were from central and states in south and north of Iran. The feet were most affected site (65.7% of the cases, followed by hands (25.7%, face (2.8%, and trunk (2.8%, and buttock (2.8%. Most patients (68.5% were more than 40 year-old. The male to female ratio was 5:3. The disease was abundant among housewife in urban and farmer in rural area of Iran. The most common prevalent mycetoma agents in this study were Actinomyces sp. There was a history of risk factors in 28.6% of patients in this study. Conclusion: Mycetoma occasionally occurs particularly in the South, Central, and North of Iran, and seen most often in persons, who live in hot, humid climates. If there are risk factors for invasive fungal infections traumatic inoculation with any fungus may result in rapid local spread and systemic disease, often with fatal outcome.

  19. Changes in blood sugar levels of rats experimentally infected withTrypanosoma brucei and treated with imidocarb dipropionate and diminazene aceturate

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omalathebu


    Objective:To determine the effect ofTrypanosoma brucei (T. brucei) on blood sugar level of infected rats. Methods: The experiment was done with 42 albino rats grouped into 3 groups of 14 members each. Group A was uninfected (control group), Group B was infected withT. brucei and treated with diminazene aceturate, and Group C was infected withT. brucei and treated with imidocarb dipropionate. Blood samples were collected from the media canthus of the experimental rats on Days 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 for the assessment of change in blood sugar levels. The blood sugar levels were determined with a glucometer (Accu-chek active serialNo.GN:10023338). Results: By 4 to 5 days post infection, there was a significant increase (P 0.05) was observed in the groups when compared with the control group till Day 12 of the experiment. Conclusions:T. brucei caused a significant increase in blood sugar of infected rats.

  20. Isothermal microcalorimetry, a new tool to monitor drug action against Trypanosoma brucei and Plasmodium falciparum.

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    Tanja Wenzler

    Full Text Available Isothermal microcalorimetry is an established tool to measure heat flow of physical, chemical or biological processes. The metabolism of viable cells produces heat, and if sufficient cells are present, their heat production can be assessed by this method. In this study, we investigated the heat flow of two medically important protozoans, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Heat flow signals obtained for these pathogens allowed us to monitor parasite growth on a real-time basis as the signals correlated with the number of viable cells. To showcase the potential of microcalorimetry for measuring drug action on pathogenic organisms, we tested the method with three antitrypanosomal drugs, melarsoprol, suramin and pentamidine and three antiplasmodial drugs, chloroquine, artemether and dihydroartemisinin, each at two concentrations on the respective parasite. With the real time measurement, inhibition was observed immediately by a reduced heat flow compared to that in untreated control samples. The onset of drug action, the degree of inhibition and the time to death of the parasite culture could conveniently be monitored over several days. Microcalorimetry is a valuable element to be added to the toolbox for drug discovery for protozoal diseases such as human African trypanosomiasis and malaria. The method could probably be adapted to other protozoan parasites, especially those growing extracellularly.

  1. Dynamic modelling under uncertainty: the case of Trypanosoma brucei energy metabolism.

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    Fiona Achcar


    Full Text Available Kinetic models of metabolism require detailed knowledge of kinetic parameters. However, due to measurement errors or lack of data this knowledge is often uncertain. The model of glycolysis in the parasitic protozoan Trypanosoma brucei is a particularly well analysed example of a quantitative metabolic model, but so far it has been studied with a fixed set of parameters only. Here we evaluate the effect of parameter uncertainty. In order to define probability distributions for each parameter, information about the experimental sources and confidence intervals for all parameters were collected. We created a wiki-based website dedicated to the detailed documentation of this information: the SilicoTryp wiki ( Using information collected in the wiki, we then assigned probability distributions to all parameters of the model. This allowed us to sample sets of alternative models, accurately representing our degree of uncertainty. Some properties of the model, such as the repartition of the glycolytic flux between the glycerol and pyruvate producing branches, are robust to these uncertainties. However, our analysis also allowed us to identify fragilities of the model leading to the accumulation of 3-phosphoglycerate and/or pyruvate. The analysis of the control coefficients revealed the importance of taking into account the uncertainties about the parameters, as the ranking of the reactions can be greatly affected. This work will now form the basis for a comprehensive Bayesian analysis and extension of the model considering alternative topologies.

  2. Flux Analysis of the Trypanosoma brucei Glycolysis Based on a Multiobjective-Criteria Bioinformatic Approach

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    Amine Ghozlane


    Full Text Available Trypanosoma brucei is a protozoan parasite of major of interest in discovering new genes for drug targets. This parasite alternates its life cycle between the mammal host(s (bloodstream form and the insect vector (procyclic form, with two divergent glucose metabolism amenable to in vitro culture. While the metabolic network of the bloodstream forms has been well characterized, the flux distribution between the different branches of the glucose metabolic network in the procyclic form has not been addressed so far. We present a computational analysis (called Metaboflux that exploits the metabolic topology of the procyclic form, and allows the incorporation of multipurpose experimental data to increase the biological relevance of the model. The alternatives resulting from the structural complexity of networks are formulated as an optimization problem solved by a metaheuristic where experimental data are modeled in a multiobjective function. Our results show that the current metabolic model is in agreement with experimental data and confirms the observed high metabolic flexibility of glucose metabolism. In addition, Metaboflux offers a rational explanation for the high flexibility in the ratio between final products from glucose metabolism, thsat is, flux redistribution through the malic enzyme steps.

  3. Identification and characterization of an unusual class I myosin involved in vesicle traffic in Trypanosoma brucei.

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    Diana Spitznagel

    Full Text Available Myosins are a multimember family of motor proteins with diverse functions in eukaryotic cells. African trypanosomes possess only two candidate myosins and thus represent a useful system for functional analysis of these motors. One of these candidates is an unusual class I myosin (TbMyo1 that is expressed at similar levels but organized differently during the life cycle of Trypanosoma brucei. This myosin localizes to the polarized endocytic pathway in bloodstream forms of the parasite. This organization is actin dependent. Knock down of TbMyo1 results in a significant reduction in endocytic activity, a cessation in cell division and eventually cell death. A striking morphological feature in these cells is an enlargement of the flagellar pocket, which is consistent with an imbalance in traffic to and from the surface. In contrast TbMyo1 is distributed throughout procyclic forms of the tsetse vector and a loss of approximately 90% of the protein has no obvious effects on growth or morphology. These results reveal a life cycle stage specific requirement for this myosin in essential endocytic traffic and represent the first description of the involvement of a motor protein in vesicle traffic in these parasites.

  4. Identification and characterization of an unusual class I myosin involved in vesicle traffic in Trypanosoma brucei. (United States)

    Spitznagel, Diana; O'Rourke, John F; Leddy, Neal; Hanrahan, Orla; Nolan, Derek P


    Myosins are a multimember family of motor proteins with diverse functions in eukaryotic cells. African trypanosomes possess only two candidate myosins and thus represent a useful system for functional analysis of these motors. One of these candidates is an unusual class I myosin (TbMyo1) that is expressed at similar levels but organized differently during the life cycle of Trypanosoma brucei. This myosin localizes to the polarized endocytic pathway in bloodstream forms of the parasite. This organization is actin dependent. Knock down of TbMyo1 results in a significant reduction in endocytic activity, a cessation in cell division and eventually cell death. A striking morphological feature in these cells is an enlargement of the flagellar pocket, which is consistent with an imbalance in traffic to and from the surface. In contrast TbMyo1 is distributed throughout procyclic forms of the tsetse vector and a loss of approximately 90% of the protein has no obvious effects on growth or morphology. These results reveal a life cycle stage specific requirement for this myosin in essential endocytic traffic and represent the first description of the involvement of a motor protein in vesicle traffic in these parasites.

  5. The Role of Folate Transport in Antifolate Drug Action in Trypanosoma brucei* (United States)

    Dewar, Simon; Sienkiewicz, Natasha; Ong, Han B.; Wall, Richard J.; Horn, David


    The aim of this study was to identify and characterize mechanisms of resistance to antifolate drugs in African trypanosomes. Genome-wide RNAi library screens were undertaken in bloodstream form Trypanosoma brucei exposed to the antifolates methotrexate and raltitrexed. In conjunction with drug susceptibility and folate transport studies, RNAi knockdown was used to validate the functions of the putative folate transporters. The transport kinetics of folate and methotrexate were further characterized in whole cells. RNA interference target sequencing experiments identified a tandem array of genes encoding a folate transporter family, TbFT1–3, as major contributors to antifolate drug uptake. RNAi knockdown of TbFT1–3 substantially reduced folate transport into trypanosomes and reduced the parasite's susceptibly to the classical antifolates methotrexate and raltitrexed. In contrast, knockdown of TbFT1–3 increased susceptibly to the non-classical antifolates pyrimethamine and nolatrexed. Both folate and methotrexate transport were inhibited by classical antifolates but not by non-classical antifolates or biopterin. Thus, TbFT1–3 mediates the uptake of folate and classical antifolates in trypanosomes, and TbFT1–3 loss-of-function is a mechanism of antifolate drug resistance. PMID:27703008

  6. Crystal structures and inhibition of Trypanosoma brucei hypoxanthine–guanine phosphoribosyltransferase (United States)

    Terán, David; Hocková, Dana; Česnek, Michal; Zíková, Alena; Naesens, Lieve; Keough, Dianne T.; Guddat, Luke W.


    Human African Trypanosomiasis (HAT) is a life-threatening infectious disease caused by the protozoan parasite, Trypanosoma brucei (Tbr). Due to the debilitating side effects of the current therapeutics and the emergence of resistance to these drugs, new medications for this disease need to be developed. One potential new drug target is 6-oxopurine phosphoribosyltransferase (PRT), an enzyme central to the purine salvage pathway and whose activity is critical for the production of the nucleotides (GMP and IMP) required for DNA/RNA synthesis within this protozoan parasite. Here, the first crystal structures of this enzyme have been determined, these in complex with GMP and IMP and with three acyclic nucleoside phosphonate (ANP) inhibitors. The Ki values for GMP and IMP are 30.5 μM and 77 μM, respectively. Two of the ANPs have Ki values considerably lower than for the nucleotides, 2.3 μM (with guanine as base) and 15.8 μM (with hypoxanthine as base). The crystal structures show that when two of the ANPs bind, they induce an unusual conformation change to the loop where the reaction product, pyrophosphate, is expected to bind. This and other structural differences between the Tbr and human enzymes suggest selective inhibitors for the Tbr enzyme can be designed. PMID:27786284

  7. Melarsoprol- and pentamidine-resistant Trypanosoma brucei rhodesiense populations and their cross-resistance. (United States)

    Bernhard, Sonja C; Nerima, Barbara; Mäser, Pascal; Brun, Reto


    Resistance to melarsoprol and pentamidine was induced in bloodstream-form Trypanosoma brucei rhodesiense STIB 900 in vitro, and drug sensitivity was determined for melarsoprol, pentamidine and furamidine. The resistant populations were also inoculated into immunosuppressed mice to verify infectivity and to monitor whether rodent passage selects for clones with altered drug sensitivity. After proliferation in the mouse, trypanosomes were isolated and their IC(50) values to the three drugs were determined. To assess the stability of drug-induced resistance, drug pressure was ceased for 2 months and the drug sensitivity was determined again. Resistance was stable, with a few exceptions that are discussed. Drug IC(50)s indicated cross-resistance among all drugs, but to varying extents: resistance of the melarsoprol-selected and pentamidine-selected trypanosomes to pentamidine was the same, but the pentamidine-selected trypanosome population showed lower resistance to melarsoprol than the melarsoprol-selected trypanosomes. Interestingly, both resistant populations revealed the same intermediate cross-resistance to furamidine. Resistant trypanosome populations were characterised by molecular means, referring to the status of the TbAT1 gene. The melarsoprol-selected population apparently had lost TbAT1, whereas in the pentamidine-selected trypanosome population it was still present.

  8. Association of a novel preribosomal complex in Trypanosoma brucei determined by fluorescence resonance energy transfer. (United States)

    Wang, Lei; Ciganda, Martin; Williams, Noreen


    We have previously reported that the trypanosome-specific proteins P34 and P37 form a unique preribosomal complex with ribosomal protein L5 and 5S rRNA in the nucleoplasm. We hypothesize that this novel trimolecular complex is necessary for stabilizing 5S rRNA in Trypanosoma brucei and is essential for the survival of the parasite. In vitro quantitative analysis of the association between the proteins L5 and P34 is fundamental to our understanding of this novel complex and thus our ability to exploit its unique characteristics. Here we used in vitro fluorescence resonance energy transfer (FRET) to analyze the association between L5 and P34. First, we demonstrated that FRET can be used to confirm the association between L5 and P34. We then determined that the binding constant for L5 and P34 is 0.60 ± 0.03 μM, which is in the range of protein-protein binding constants for RNA binding proteins. In addition, we used FRET to identify the critical regions of L5 and P34 involved in the protein-protein association. We found that the N-terminal APK-rich domain and RNA recognition motif (RRM) of P34 and the L18 domain of L5 are important for the association of the two proteins with each other. These results provide us with the framework for the discovery of ways to disrupt this essential complex.

  9. Fluorinated Sterols Are Suicide Inhibitors of Ergosterol Biosynthesis and Growth in Trypanosoma brucei. (United States)

    Leaver, David J; Patkar, Presheet; Singha, Ujjal K; Miller, Matthew B; Haubrich, Brad A; Chaudhuri, Minu; Nes, W David


    Trypanosoma brucei, the causal agent for sleeping sickness, depends on ergosterol for growth. Here, we describe the effects of a mechanism-based inhibitor, 26-fluorolanosterol (26FL), which converts in vivo to a fluorinated substrate of the sterol C24-methyltransferase essential for sterol methylation and function of ergosterol, and missing from the human host. 26FL showed potent inhibition of ergosterol biosynthesis and growth of procyclic and bloodstream forms while having no effect on cholesterol biosynthesis or growth of human epithelial kidney cells. During exposure of cloned TbSMT to 26-fluorocholesta-5,7,24-trienol, the enzyme is gradually killed as a consequence of the covalent binding of the intermediate C25 cation to the active site (kcat/kinact = 0.26 min(-1)/0.24 min(-1); partition ratio of 1.08), whereas 26FL is non-productively bound. These results demonstrate that poisoning of ergosterol biosynthesis by a 26-fluorinated Δ(24)-sterol is a promising strategy for developing a new treatment for trypanosomiasis.

  10. Parasite development and host responses during the establishment of Trypanosoma brucei infection transmitted by tsetse fly. (United States)

    Barry, J D; Emergy, D L


    Following inoculation of Trypanosoma brucei into large mammals by the tsetse fly a local skin reaction, the 'chancre', develops due to trypanosome proliferation. We have cannulated the afferent and efferent lymphatics of the draining lymph node in goats and examined the onset of a cellular reaction, the emigration of the parasite from the chancre and the development of both antigenic variation and the specific immune response. The chancre first became detectable by day 3 post-infection, peaked by day 6 and then subsided. Lymphocyte output increased 6- to 8-fold by day 10 and the number of lymphoblasts increased 50-fold in this period. Both then declined. Trypanosomes were detected in lymph 1-2 days before the chancre, peaked by days 5-6, declined during development of the chancre and then peaked again. The bloodstream population appeared by days 4-5 and displayed different kinetics from that in lymph. Recirculation of parasites through the lymphatics ensued. Lymph-borne trypanosome populations were highly pleomorphic. Parasites in lymph expressed firstly a mixture of the Variable Antigen Types (VATs) which are found characteristically in the tsetse fly, this being followed by a mixture of other VATs. The two groups overlapped in appearance. In the bloodstream the same sequence of events occurred although 2 or 3 days later. The specific antibody response, as measured by radioimmunoassay and agglutination, arose within a few days of the first detection of each VAT. Activities appeared first in the lymph and then in plasma.

  11. Synchronous expression of individual metacyclic variant surface glycoprotein genes in Trypanosoma brucei. (United States)

    Ramey-Butler, Kiantra; Ullu, Elisabetta; Kolev, Nikolay G; Tschudi, Christian


    One distinctive feature of the Trypanosoma brucei life cycle is the presence of two discrete populations that are based on differential expression of variant surface glycoproteins (VSGs). Both are adapted to the environmental pressures they face and more importantly, both contribute directly to transmission. Metacyclics in the tsetse fly enable transmission to a new mammalian host, whereas bloodstream trypanosomes must avoid immune destruction to the extent that sufficient numbers are available for transmission, when the insect vector takes a blood meal. At present, there are few investigations on the molecular aspects of parasite biology in the tsetse vector and specifically about the activation of metacyclic VSG gene expression. Here we used an established in vitro differentiation system based on the overexpression of the RNA-binding protein 6 (RBP6), to monitor two metacyclic VSGs (VSG 397 and VSG 653) during development from procyclics to infectious metacyclic forms. We observed that activation of these two mVSGs was simultaneous both at the transcript and protein level, and manifested by the appearance of only one of the mVSGs in individual cells.

  12. Identification of a new EF-hand superfamily member from Trypanosoma brucei (United States)

    Wong, S.; Kretsinger, R. H.; Campbell, D. A.


    We identified several open reading frames between the regions encoding calmodulin and ubiquitin-EP52/1 in the genome of Trypanosoma brucei. One of these, EFH5, encodes a protein 192 amino acids long. The EFH5 transcript is present in poly(A)+ mRNA and is present at similar levels in the mammalian bloodstream form and the insect procyclic form. EFH5 contains four EF-hand homolog domains, two of which are inferred to bind Ca2+ ions. We expressed EFH5 as a fusion protein in Escherichia coli and demonstrated calcium-binding activity of the fusion protein using the 45Ca-overlay technique. The function of EFH5 remains unknown; however, as the fourth EF-hand homolog identified in trypanosomes, it attests to the broad range of functions assumed by calcium functioning as a second messenger. EFH5, which is most closely related to LAV1-2 from Physarum, represents a distinct subfamily among the EF-hand-containing proteins.

  13. Rediscovery of Trypanosoma (Pycnomonas) suis, a tsetse-transmitted trypanosome closely related to T. brucei. (United States)

    Hutchinson, Rachel; Gibson, Wendy


    The African tsetse-transmitted trypanosomes are considered to be a well-known group of parasitic protozoa, but in 2008 a novel and distinctive trypanosome related to Trypanosoma brucei was discovered among tsetse isolates from Msubugwe in Tanzania. The host range, distribution and potential pathogenicity of this new trypanosome remain to be elucidated; such studies would be facilitated by a sensitive and specific identification method. Here, we identified two highly repetitive elements in the genome of the new trypanosome: a 177 bp repeat, which was located predominantly on the highly abundant minichromosomes, and a 138 bp repeat, which was widely dispersed in the genome. A PCR test based on each repeat was specific for the new trypanosome and sensitive to Trypanosoma (Pycnomonas) suis. We also present data on the molecular karyotype and spliced leader (SL, miniexon) repeat of the new trypanosome, both of which distinguish T. suis from other, better-known African tsetse-transmitted trypanosomes. The rediscovery of T. suis opens new lines of research into the evolution and biology of the African trypanosomes.

  14. Neurodynamics of mind: the arrow illusion of conscious intentionality as downward causation. (United States)

    Barutta, Joaquín; Gleichgerrcht, Ezequiel; Cornejo, Carlos; Ibáñez, Agustín


    In cognitive neuroscience, the reissue of the notion of emergence and downward causation has been used as an interlevel model of mind-brain interactions from different perspectives. Within this perspective, intentionality has been interpreted as global to local determination (downward causation) on the neurophysiological level. Consciousness would act as the large-scale, global activity of the system that governs or constrains local interactions of neurons. This argument seems to solve several difficulties with regard to descriptions of consciousness on a neurophysiological and mental level. Nevertheless, the inconsistencies of this argument are shown, and a contextual and pragmatic explanation of the downward causation of consciousness is given.

  15. Stepping towards causation in studies of neighborhood and environmental effects: how twin research can overcome problems of selection and reverse causation. (United States)

    Duncan, Glen E; Mills, Brianna; Strachan, Eric; Hurvitz, Philip; Huang, Ruizhu; Moudon, Anne Vernez; Turkheimer, Eric


    No causal evidence is available to translate associations between neighborhood characteristics and health outcomes into beneficial changes to built environments. Observed associations may be causal or result from uncontrolled confounds related to family upbringing. Twin designs can help neighborhood effects studies overcome selection and reverse causation problems in specifying causal mechanisms. Beyond quantifying genetic effects (i.e., heritability coefficients), we provide examples of innovative measures and analytic methods that use twins as quasi-experimental controls for confounding by environmental effects. We conclude that collaboration among investigators from multiple fields can move the field forward by designing studies that step toward causation.

  16. New functions for parts of the Krebs cycle in procyclic Trypanosoma brucei, a cycle not operating as a cycle. (United States)

    van Weelden, Susanne W H; van Hellemond, Jaap J; Opperdoes, Fred R; Tielens, Aloysius G M


    We investigated whether substrate availability influences the type of energy metabolism in procyclic Trypanosoma brucei. We show that absence of glycolytic substrates (glucose and glycerol) does not induce a shift from a fermentative metabolism to complete oxidation of substrates. We also show that glucose (and even glycolysis) is not essential for normal functioning and proliferation of pleomorphic procyclic T. brucei cells. Furthermore, absence of glucose did not result in increased degradation of amino acids. Variations in availability of glucose and glycerol did result, however, in adaptations in metabolism in such a way that the glycosome was always in redox balance. We argue that it is likely that, in procyclic cells, phosphoglycerate kinase is located not only in the cytosol, but also inside glycosomes, as otherwise an ATP deficit would occur in this organelle. We demonstrate that procyclic T. brucei uses parts of the Krebs cycle for purposes other than complete degradation of mitochondrial substrates. We suggest that citrate synthase plus pyruvate dehydrogenase and malate dehydrogenase are used to transport acetyl-CoA units from the mitochondrion to the cytosol for the biosynthesis of fatty acids, a process we show to occur in proliferating procyclic cells. The part of the Krebs cycle consisting of alpha-ketoglutarate dehydrogenase and succinyl-CoA synthetase was used for the degradation of proline and glutamate to succinate. We also demonstrate that the subsequent enzymes of the Krebs cycle, succinate dehydrogenase and fumarase, are most likely used for conversion of succinate into malate, which can then be used in gluconeogenesis.

  17. National Motor Vehicle Crash Causation Survey (NMVCCS) - NMVCCS XML Case Viewer (United States)

    Department of Transportation — The National Motor Vehicle Crash Causation Survey (NMVVCS) was a nationwide survey of crashes involving light passenger vehicles, with a focus on the factors related...

  18. Kasi and bikin Two causative strategies in Melayu Tenggara Jauh (Southwest Maluku, Indonesia

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    Aone van Engelenhoven


    Full Text Available This paper  discusses the causative constructions found in Melayu Tenggara Jauh ‘Far Southeast Malay’ (MTJ, which is used as lingua franca in Southwest Maluku.  MTJ encodes causatives by means of MTJ features four periphrastic constructions with the verbs bikin ‘do/make’ and kasi ‘give’ that signal whether or not the CAUSER (Kemmer and Verhagen 1994 is involved in or has control over the caused event.

  19. An expression of closure to efficient causation in terms of lambda-calculus


    Mossio, Matteo; Longo, Giuseppe; Stewart, John


    Abstract In this paper, we propose a mathematical expression of closure to efficient causation in terms of ?-calculus; we argue that this opens up the perspective of developing principled computer simulations of systems closed to efficient causation in an appropriate programming language. An important implication of our formulation is that, by exhibiting an expression in ?-calculus, which is a paradigmatic formalism for computability and programming, we show that there are no conce...


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    A. V. Kozhokina


    Full Text Available The paper deals with studying special features of English causative verbs to cause and to make in passive construction. The conclusion is drawn that the given verbs in passive construction have certain differences. Having their causative meaning, they form different semantic situations. The verb to cause forms a situation: «B is caused by A» whereas the verb to make forms the situation «Y is made to do/ become P». Their semantic difference results in the syntax variation. The passive construction with the verb to cause must definitely contain information about the causator, which is a subject in the structure. The verb to make in passive construction can describe 1 a situation when an object of causation takes part in the process which he can’t control, or when he performs smth against his will, 2 a situation when the object of causation can’t resist performing an action, 3 an action can’t be performed without anybody’s help. As a rule, in passive construction with the verb to make the causator in not expressed.

  1. Structure and reactivity of Trypanosoma brucei pteridine reductase: inhibition by the archetypal antifolate methotrexate. (United States)

    Dawson, Alice; Gibellini, Federica; Sienkiewicz, Natasha; Tulloch, Lindsay B; Fyfe, Paul K; McLuskey, Karen; Fairlamb, Alan H; Hunter, William N


    The protozoan Trypanosoma brucei has a functional pteridine reductase (TbPTR1), an NADPH-dependent short-chain reductase that participates in the salvage of pterins, which are essential for parasite growth. PTR1 displays broad-spectrum activity with pterins and folates, provides a metabolic bypass for inhibition of the trypanosomatid dihydrofolate reductase and therefore compromises the use of antifolates for treatment of trypanosomiasis. Catalytic properties of recombinant TbPTR1 and inhibition by the archetypal antifolate methotrexate have been characterized and the crystal structure of the ternary complex with cofactor NADP+ and the inhibitor determined at 2.2 A resolution. This enzyme shares 50% amino acid sequence identity with Leishmania major PTR1 (LmPTR1) and comparisons show that the architecture of the cofactor binding site, and the catalytic centre are highly conserved, as are most interactions with the inhibitor. However, specific amino acid differences, in particular the placement of Trp221 at the side of the active site, and adjustment of the beta6-alpha6 loop and alpha6 helix at one side of the substrate-binding cleft significantly reduce the size of the substrate binding site of TbPTR1 and alter the chemical properties compared with LmPTR1. A reactive Cys168, within the active site cleft, in conjunction with the C-terminus carboxyl group and His267 of a partner subunit forms a triad similar to the catalytic component of cysteine proteases. TbPTR1 therefore offers novel structural features to exploit in the search for inhibitors of therapeutic value against African trypanosomiasis.

  2. 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction.

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    Johanna L Höög


    Full Text Available Cellular junctions are crucial for the formation of multicellular organisms, where they anchor cells to each other and/or supportive tissue and enable cell-to-cell communication. Some unicellular organisms, such as the parasitic protist Trypanosoma brucei, also have complex cellular junctions. The flagella connector (FC is a three-layered transmembrane junction that moves with the growing tip of a new flagellum and attaches it to the side of the old flagellum. The FC moves via an unknown molecular mechanism, independent of new flagellum growth. Here we describe the detailed 3D architecture of the FC suggesting explanations for how it functions and its mechanism of motility.We have used a combination of electron tomography and cryo-electron tomography to reveal the 3D architecture of the FC. Cryo-electron tomography revealed layers of repetitive filamentous electron densities between the two flagella in the interstitial zone. Though the FC does not change in length and width during the growth of the new flagellum, the interstitial zone thickness decreases as the FC matures. This investigation also shows interactions between the FC layers and the axonemes of the new and old flagellum, sufficiently strong to displace the axoneme in the old flagellum. We describe a novel filament, the flagella connector fibre, found between the FC and the axoneme in the old flagellum.The FC is similar to other cellular junctions in that filamentous proteins bridge the extracellular space and are anchored to underlying cytoskeletal structures; however, it is built between different portions of the same cell and is unique because of its intrinsic motility. The detailed description of its structure will be an important tool to use in attributing structure / function relationships as its molecular components are discovered in the future. The FC is involved in the inheritance of cell shape, which is important for the life cycle of this human parasite.

  3. Genome-wide dissection of the quorum sensing signalling pathway in Trypanosoma brucei. (United States)

    Mony, Binny M; MacGregor, Paula; Ivens, Alasdair; Rojas, Federico; Cowton, Andrew; Young, Julie; Horn, David; Matthews, Keith


    The protozoan parasites Trypanosoma brucei spp. cause important human and livestock diseases in sub-Saharan Africa. In mammalian blood, two developmental forms of the parasite exist: proliferative 'slender' forms and arrested 'stumpy' forms that are responsible for transmission to tsetse flies. The slender to stumpy differentiation is a density-dependent response that resembles quorum sensing in microbial systems and is crucial for the parasite life cycle, ensuring both infection chronicity and disease transmission. This response is triggered by an elusive 'stumpy induction factor' (SIF) whose intracellular signalling pathway is also uncharacterized. Laboratory-adapted (monomorphic) trypanosome strains respond inefficiently to SIF but can generate forms with stumpy characteristics when exposed to cell-permeable cAMP and AMP analogues. Exploiting this, we have used a genome-wide RNA interference library screen to identify the signalling components driving stumpy formation. In separate screens, monomorphic parasites were exposed to 8-(4-chlorophenylthio)-cAMP (pCPT-cAMP) or 8-pCPT-2'-O-methyl-5'-AMP to select cells that were unresponsive to these signals and hence remained proliferative. Genome-wide Ion Torrent based RNAi target sequencing identified cohorts of genes implicated in each step of the signalling pathway, from purine metabolism, through signal transducers (kinases, phosphatases) to gene expression regulators. Genes at each step were independently validated in cells naturally capable of stumpy formation, confirming their role in density sensing in vivo. The putative RNA-binding protein, RBP7, was required for normal quorum sensing and promoted cell-cycle arrest and transmission competence when overexpressed. This study reveals that quorum sensing signalling in trypanosomes shares similarities to fundamental quiescence pathways in eukaryotic cells, its components providing targets for quorum-sensing interference-based therapeutics.

  4. Loop-mediated isothermal amplification (LAMP method for rapid detection of Trypanosoma brucei rhodesiense.

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    Zablon Kithinji Njiru

    Full Text Available Loop-mediated isothermal amplification (LAMP of DNA is a novel technique that rapidly amplifies target DNA under isothermal conditions. In the present study, a LAMP test was designed from the serum resistance-associated (SRA gene of Trypanosoma brucei rhodesiense, the cause of the acute form of African sleeping sickness, and used to detect parasite DNA from processed and heat-treated infected blood samples. The SRA gene is specific to T. b. rhodesiense and has been shown to confer resistance to lysis by normal human serum. The assay was performed at 62 degrees C for 1 h, using six primers that recognised eight targets. The template was varying concentrations of trypanosome DNA and supernatant from heat-treated infected blood samples. The resulting amplicons were detected using SYTO-9 fluorescence dye in a real-time thermocycler, visual observation after the addition of SYBR Green I, and gel electrophoresis. DNA amplification was detected within 35 min. The SRA LAMP test had an unequivocal detection limit of one pg of purified DNA (equivalent to 10 trypanosomes/ml and 0.1 pg (1 trypanosome/ml using heat-treated buffy coat, while the detection limit for conventional SRA PCR was approximately 1,000 trypanosomes/ml. The expected LAMP amplicon was confirmed through restriction enzyme RsaI digestion, identical melt curves, and sequence analysis. The reproducibility of the SRA LAMP assay using water bath and heat-processed template, and the ease in results readout show great potential for the diagnosis of T. b. rhodesiense in endemic regions.

  5. A monoclonal antibody marker for the exclusion-zone filaments of Trypanosoma brucei

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    Decossas Marion


    Full Text Available Abstract Background Trypanosoma brucei is a haemoflagellate pathogen of man, wild animals and domesticated livestock in central and southern Africa. In all life cycle stages this parasite has a single mitochondrion that contains a uniquely organised genome that is condensed into a flat disk-like structure called the kinetoplast. The kinetoplast is essential for insect form procyclic cells and therefore is a potential drug target. The kinetoplast is unique in nature because it consists of novel structural proteins and thousands of circular, interlocking, DNA molecules (kDNA. Secondly, kDNA replication is critically timed to coincide with nuclear S phase and new flagellum biogenesis. Thirdly, the kinetoplast is physically attached to the flagellum basal bodies via a structure called the tripartite attachment complex (TAC. The TAC consists of unilateral filaments (within the mitochondrion matrix, differentiated mitochondrial membranes and exclusion-zone filaments that extend from the distal end of the basal bodies. To date only one protein, p166, has been identified to be a component of the TAC. Results In the work presented here we provide data based on a novel EM technique developed to label and characterise cytoskeleton structures in permeabilised cells without extraction of mitochondrion membranes. We use this protocol to provide data on a new monoclonal antibody reagent (Mab 22 and illustrate the precise localisation of basal body-mitochondrial linker proteins. Mab 22 binds to these linker proteins (exclusion-zone filaments and provides a new tool for the characterisation of cytoskeleton mediated kinetoplast segregation. Conclusion The antigen(s recognised by Mab 22 are cytoskeletal, insensitive to extraction by high concentrations of non-ionic detergent, extend from the proximal region of basal bodies and bind to the outer mitochondrial membrane. This protein(s is the first component of the TAC exclusion-zone fibres to be identified. Mab 22

  6. Enhanced succinic acid production in Aspergillus saccharolyticus by heterologous expression of fumarate reductase from Trypanosoma brucei. (United States)

    Yang, Lei; Lübeck, Mette; Ahring, Birgitte K; Lübeck, Peter S


    Aspergillus saccharolyticus exhibits great potential as a cell factory for industrial production of dicarboxylic acids. In the analysis of the organic acid profile, A. saccharolyticus was cultivated in an acid production medium using two different pH conditions. The specific activities of the enzymes, pyruvate carboxylase (PYC), malate dehydrogenase (MDH), and fumarase (FUM), involved in the reductive tricarboxylic acid (rTCA) branch, were examined and compared in cells harvested from the acid production medium and a complete medium. The results showed that ambient pH had a significant impact on the pattern and the amount of organic acids produced by A. saccharolyticus. The wild-type strain produced higher amount of malic acid and succinic acid in the pH buffered condition (pH 6.5) compared with the pH non-buffered condition. The enzyme assays showed that the rTCA branch was active in the acid production medium as well as the complete medium, but the measured enzyme activities were different depending on the media. Furthermore, a soluble NADH-dependent fumarate reductase gene (frd) from Trypanosoma brucei was inserted and expressed in A. saccharolyticus. The expression of the frd gene led to an enhanced production of succinic acid in frd transformants compared with the wild-type in both pH buffered and pH non-buffered conditions with highest amount produced in the pH buffered condition (16.2 ± 0.5 g/L). This study demonstrates the feasibility of increasing succinic acid production through the cytosolic reductive pathway by genetic engineering in A. saccharolyticus.

  7. The F(0F(1-ATP synthase complex contains novel subunits and is essential for procyclic Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Alena Zíková


    Full Text Available The mitochondrial F(0F(1 ATP synthase is an essential multi-subunit protein complex in the vast majority of eukaryotes but little is known about its composition and role in Trypanosoma brucei, an early diverged eukaryotic pathogen. We purified the F(0F(1 ATP synthase by a combination of affinity purification, immunoprecipitation and blue-native gel electrophoresis and characterized its composition and function. We identified 22 proteins of which five are related to F(1 subunits, three to F(0 subunits, and 14 which have no obvious homology to proteins outside the kinetoplastids. RNAi silencing of expression of the F(1 alpha subunit or either of the two novel proteins showed that they are each essential for the viability of procyclic (insect stage cells and are important for the structural integrity of the F(0F(1-ATP synthase complex. We also observed a dramatic decrease in ATP production by oxidative phosphorylation after silencing expression of each of these proteins while substrate phosphorylation was not severely affected. Our procyclic T. brucei cells were sensitive to the ATP synthase inhibitor oligomycin even in the presence of glucose contrary to earlier reports. Hence, the two novel proteins appear essential for the structural organization of the functional complex and regulation of mitochondrial energy generation in these organisms is more complicated than previously thought.

  8. Complete coding sequence, sequence analysis and transmembrane topology modelling of Trypanosoma brucei rhodesiense putative oligosaccharyl transferase (TbOST II). (United States)

    Baticados, Waren N; Inoue, Noboru; Sugimoto, Chihiro; Nagasawa, Hideyuki; Baticados, Abigail M


    The partial nucleotide sequence of putative Trypanosoma brucei rhodesiense oligosaccharyl transferase gene was previously reported. Here, we describe the determination of its full-length nucleotide sequence by Inverse PCR (IPCR), subsequent biological sequence analysis and transmembrane topology modelling. The full-length DNA sequence has an Open Reading Frame (ORF) of 2406 bp and encodes a polypeptide of 801 amino acid residues. Protein and DNA sequence analyses revealed that homologues within the genome of other kinetoplastid and various origins exist. Protein topology analysis predicted that Trypanosoma brucei rhodesiense putative oligosaccharyl transferase clone II (TbOST II) is a transmembrane protein with transmembrane helices in probably an N(cytosol)-C(cytosol) orientation. Data from the GenBank database assembly and sequence analyses in general clearly state that TbOST II is the STT3 subunit of OST in T.b. rhodesiense that necessitates further characterisation and functional studies with RNAi. TbOST II sequence had been deposited in the GenBank (accession number GU245937).

  9. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase

    Directory of Open Access Journals (Sweden)

    Fabian C. Herrmann


    Full Text Available As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany, against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH, a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9% were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69% showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  10. SAS-4 Protein in Trypanosoma brucei Controls Life Cycle Transitions by Modulating the Length of the Flagellum Attachment Zone Filament. (United States)

    Hu, Huiqing; Zhou, Qing; Li, Ziyin


    The evolutionarily conserved centriole/basal body protein SAS-4 regulates centriole duplication in metazoa and basal body duplication in flagellated and ciliated organisms. Here, we report that the SAS-4 homolog in the flagellated protozoan Trypanosoma brucei, TbSAS-4, plays an unusual role in controlling life cycle transitions by regulating the length of the flagellum attachment zone (FAZ) filament, a specialized cytoskeletal structure required for flagellum adhesion and cell morphogenesis. TbSAS-4 is concentrated at the distal tip of the FAZ filament, and depletion of TbSAS-4 in the trypomastigote form disrupts the elongation of the new FAZ filament, generating cells with a shorter FAZ associated with a longer unattached flagellum and repositioned kinetoplast and basal body, reminiscent of epimastigote-like morphology. Further, we show that TbSAS-4 associates with six additional FAZ tip proteins, and depletion of TbSAS-4 disrupts the enrichment of these FAZ tip proteins at the new FAZ tip, suggesting a role of TbSAS-4 in maintaining the integrity of this FAZ tip protein complex. Together, these results uncover a novel function of TbSAS-4 in regulating the length of the FAZ filament to control basal body positioning and life cycle transitions in T. brucei.

  11. Deviating the level of proliferating cell nuclear antigen in Trypanosoma brucei elicits distinct mechanisms for inhibiting proliferation and cell cycle progression. (United States)

    Valenciano, Ana L; Ramsey, Aaron C; Mackey, Zachary B


    The DNA replication machinery is spatially and temporally coordinated in all cells to reproduce a single exact copy of the genome per division, but its regulation in the protozoan parasite Trypanosoma brucei is not well characterized. We characterized the effects of altering the levels of proliferating cell nuclear antigen, a key component of the DNA replication machinery, in bloodstream form T. brucei. This study demonstrated that tight regulation of TbPCNA levels was critical for normal proliferation and DNA replication in the parasite. Depleting TbPCNA mRNA reduced proliferation, severely diminished DNA replication, arrested the synthesis of new DNA and caused the parasites to accumulated in G2/M. Attenuating the parasite by downregulating TbPCNA caused it to become hypersensitive to hydroxyurea. Overexpressing TbPCNA in T. brucei arrested proliferation, inhibited DNA replication and prevented the parasite from exiting G2/M. These results indicate that distinct mechanisms of cell cycle arrest are associated with upregulating or downregulating TbPCNA. The findings of this study validate deregulating intra-parasite levels of TbPCNA as a potential strategy for therapeutically exploiting this target in bloodstream form T. brucei.

  12. Identification and characterization of hundreds of potent and selective inhibitors of Trypanosoma brucei growth from a kinase-targeted library screening campaign.

    Directory of Open Access Journals (Sweden)

    Rosario Diaz


    Full Text Available In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in Trypanosomal brucei, a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2 cells. In this way, we have identified 797 sub-micromolar inhibitors of T. brucei growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of in silico and in vitro physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of T. brucei rhodesiense with one of these compounds (NEU-1053. This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for T. brucei, and new HAT therapeutics discovery programs.

  13. Identification and characterization of hundreds of potent and selective inhibitors of Trypanosoma brucei growth from a kinase-targeted library screening campaign. (United States)

    Diaz, Rosario; Luengo-Arratta, Sandra A; Seixas, João D; Amata, Emanuele; Devine, William; Cordon-Obras, Carlos; Rojas-Barros, Domingo I; Jimenez, Elena; Ortega, Fatima; Crouch, Sabrinia; Colmenarejo, Gonzalo; Fiandor, Jose Maria; Martin, Jose Julio; Berlanga, Manuela; Gonzalez, Silvia; Manzano, Pilar; Navarro, Miguel; Pollastri, Michael P


    In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in Trypanosomal brucei, a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2) cells. In this way, we have identified 797 sub-micromolar inhibitors of T. brucei growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of in silico and in vitro physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of T. brucei rhodesiense with one of these compounds (NEU-1053). This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for T. brucei, and new HAT therapeutics discovery programs.

  14. Analysis of cosmid clones of nuclear DNA from Trypanosome brucei shows that the genes for variant surface glycoproteins are clustered in the genome.

    NARCIS (Netherlands)

    D. Valerio (Dinko); T. de Lange; P. Borst (Piet); F.G. Grosveld (Frank); L.H.T. van der Ploeg


    textabstractTrypanosoma brucei contains more than a hundred genes coding for the different variant surface glycoproteins (VSGs). Activation of some of these genes involves the duplication of the gene (the basic copy or BC) and transposition of the duplicate to an expression site (yielding the expres

  15. The use of yellow fluorescent hybrids to indicate mating in Trypanosoma brucei

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    Ferris Vanessa


    Full Text Available Abstract Background Trypanosoma brucei undergoes genetic exchange in its insect vector, the tsetse fly, by an unknown mechanism. The difficulties of working with this experimental system of genetic exchange have hampered investigation, particularly because the trypanosome life cycle stages involved cannot be cultured in vitro and therefore must be examined in the insect. Searching for small numbers of hybrid trypanosomes directly in the fly has become possible through the incorporation of fluorescent reporter genes, and we have previously carried out a successful cross using a reporter-repressor strategy. However, we could not be certain that all fluorescent trypanosomes observed in that cross were hybrids, due to mutations of the repressor leading to spontaneous fluorescence, and we have therefore developed an alternative strategy. Results To visualize the production of hybrids in the fly, parental trypanosome clones were transfected with a gene encoding Green Fluorescent Protein (GFP or Red Fluorescent Protein (RFP. Co-infection of flies with red and green fluorescent parental trypanosomes produced yellow fluorescent hybrids, which were easily visualized in the fly salivary glands. Yellow trypanosomes were not seen in midgut or proventricular samples and first appeared in the glands as epimastigotes as early as 13 days after fly infection. Cloned progeny originating from individual salivary glands had yellow, red, green or no fluorescence and were confirmed as hybrids by microsatellite, molecular karyotype and kinetoplast (mitochondrial DNA analyses. Hybrid clones showed biparental inheritance of both nuclear and kinetoplast genomes. While segregation and reassortment of the reporter genes and microsatellite alleles were consistent with Mendelian inheritance, flow cytometry measurement of DNA content revealed both diploid and polyploid trypanosomes among the hybrid progeny clones. Conclusion The strategy of using production of yellow hybrids

  16. Excreted/Secreted Proteins from Trypanosome Procyclic Strains

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    Celestine Michelle Atyame Nten


    Full Text Available Trypanosoma secretome was shown to be involved in parasite virulence and is suspected of interfering in parasite life-cycle steps such as establishment in the Glossina midgut, metacyclogenesis. Therefore, we attempted to identify the proteins secreted by procyclic strains of T. brucei gambiense and T. brucei brucei, responsible for human and animal trypanosomiasis, respectively. Using mass spectrometry, 427 and 483 nonredundant proteins were characterized in T. brucei brucei and T. brucei gambiense secretomes, respectively; 35% and 42% of the corresponding secretome proteins were specifically secreted by T. brucei brucei and T. brucei gambiense, respectively, while 279 proteins were common to both subspecies. The proteins were assigned to 12 functional classes. Special attention was paid to the most abundant proteases (14 families because of their potential implication in the infection process and nutrient supply. The presence of proteins usually secreted via an exosome pathway suggests that this type of process is involved in trypanosome ESP secretion. The overall results provide leads for further research to develop novel tools for blocking trypanosome transmission.

  17. TGM6 identified as a novel causative gene of spinocerebellar ataxias using exome sequencing. (United States)

    Wang, Jun Ling; Yang, Xu; Xia, Kun; Hu, Zheng Mao; Weng, Ling; Jin, Xin; Jiang, Hong; Zhang, Peng; Shen, Lu; Guo, Ji Feng; Li, Nan; Li, Ying Rui; Lei, Li Fang; Zhou, Jie; Du, Juan; Zhou, Ya Fang; Pan, Qian; Wang, Jian; Wang, Jun; Li, Rui Qiang; Tang, Bei Sha


    Autosomal-dominant spinocerebellar ataxias constitute a large, heterogeneous group of progressive neurodegenerative diseases with multiple types. To date, classical genetic studies have revealed 31 distinct genetic forms of spinocerebellar ataxias and identified 19 causative genes. Traditional positional cloning strategies, however, have limitations for finding causative genes of rare Mendelian disorders. Here, we used a combined strategy of exome sequencing and linkage analysis to identify a novel spinocerebellar ataxia causative gene, TGM6. We sequenced the whole exome of four patients in a Chinese four-generation spinocerebellar ataxia family and identified a missense mutation, c.1550T-G transition (L517W), in exon 10 of TGM6. This change is at a highly conserved position, is predicted to have a functional impact, and completely cosegregated with the phenotype. The exome results were validated using linkage analysis. The mutation we identified using exome sequencing was located in the same region (20p13-12.2) as that identified by linkage analysis, which cross-validated TGM6 as the causative spinocerebellar ataxia gene in this family. We also showed that the causative gene could be mapped by a combined method of linkage analysis and sequencing of one sample from the family. We further confirmed our finding by identifying another missense mutation c.980A-G transition (D327G) in exon seven of TGM6 in an additional spinocerebellar ataxia family, which also cosegregated with the phenotype. Both mutations were absent in 500 normal unaffected individuals of matched geographical ancestry. The finding of TGM6 as a novel causative gene of spinocerebellar ataxia illustrates whole-exome sequencing of affected individuals from one family as an effective and cost efficient method for mapping genes of rare Mendelian disorders and the use of linkage analysis and exome sequencing for further improving efficiency.

  18. How can physics underlie the mind? top-down causation in the human context

    CERN Document Server

    Ellis, George


    Physics underlies all complexity, including our own existence: how is this possible? How can our own lives emerge from interactions of electrons, protons, and neutrons? This book considers the interaction of physical and non-physical causation in complex systems such as living beings, and in particular in the human brain, relating this to the emergence of higher levels of complexity with real causal powers. In particular it explores the idea of top-down causation, which is the key effect allowing the emergence of true complexity and also enables the causal efficacy of non-physical entities, including the value of money, social conventions, and ethical choices.

  19. The Aurora Kinase in Trypanosoma brucei plays distinctive roles in metaphase-anaphase transition and cytokinetic initiation.

    Directory of Open Access Journals (Sweden)

    Ziyin Li


    Full Text Available Aurora B kinase is an essential regulator of chromosome segregation with the action well characterized in eukaryotes. It is also implicated in cytokinesis, but the detailed mechanism remains less clear, partly due to the difficulty in separating the latter from the former function in a growing cell. A chemical genetic approach with an inhibitor of the enzyme added to a synchronized cell population at different stages of the cell cycle would probably solve this problem. In the deeply branched parasitic protozoan Trypanosoma brucei, an Aurora B homolog, TbAUK1, was found to control both chromosome segregation and cytokinetic initiation by evidence from RNAi and dominant negative mutation. To clearly separate these two functions, VX-680, an inhibitor of TbAUK1, was added to a synchronized T. brucei procyclic cell population at different cell cycle stages. The unique trans-localization pattern of the chromosomal passenger complex (CPC, consisting of TbAUK1 and two novel proteins TbCPC1 and TbCPC2, was monitored during mitosis and cytokinesis by following the migration of the proteins tagged with enhanced yellow fluorescence protein in live cells with time-lapse video microscopy. Inhibition of TbAUK1 function in S-phase, prophase or metaphase invariably arrests the cells in the metaphase, suggesting an action of TbAUK1 in promoting metaphase-anaphase transition. TbAUK1 inhibition in anaphase does not affect mitotic exit, but prevents trans-localization of the CPC from the spindle midzone to the anterior tip of the new flagellum attachment zone for cytokinetic initiation. The CPC in the midzone is dispersed back to the two segregated nuclei, while cytokinesis is inhibited. In and beyond telophase, TbAUK1 inhibition has no effect on the progression of cytokinesis or the subsequent G1, S and G2 phases until a new metaphase is attained. There are thus two clearly distinct points of TbAUK1 action in T. brucei: the metaphase-anaphase transition and

  20. Effects of supplementing Erythrina brucei leaf as a substitute for cotton seed meal on growth performance and carcass characteristics of Sidama goats fed basal diet of natural grass hay. (United States)

    Yinnesu, Asmamaw; Nurfeta, Ajebu


    The replacement value of dried Erythrina brucei leaf for cotton seed meal (CSM) on growth performance and carcass characteristics was evaluated. Twenty-five yearling buck goats (15.8 ± 1.4 kg) were assigned into five treatments in a randomized complete block design: natural grass hay alone (T1) or supplemented with 100% CSM (T2), 67% CSM + 33% E. brucei (T3), 33% CSM + 67% E. brucei (T4), and 100% E. brucei (T5) on dry matter (DM) basis. Supplemented goats consumed more (P  0.05) by the proportion of the supplements. The highest (P goats supplemented with CSM alone, whereas the lowest intake was observed in the non-supplemented group. Total CP intake decreased (P goats gained more (P goats than in the non-supplemented ones, but similar (P > 0.05) among the supplemented group. The digestibility of CP was higher (P goats, except in those goats fed E. brucei alone, than the non-supplemented group. Slaughter weight, empty body weight, hot carcass weight, dressing percentage, rib eye muscle area, and total edible offals were higher (P goats than for the non-supplemented ones. It could be concluded that E. brucei could be used as a substitute to CSM under smallholder production systems.

  1. Critical Issues in Causation and Treatment of Autism: Why Fads Continue to Flourish (United States)

    McDonald, Mary E.; Pace, Darra; Blue, Elfreda; Schwartz, Diane


    The increasing incidence of autism and the lack of specific answers regarding causation have given rise to unproven educational interventions and medical treatments. Parents of a newly diagnosed child can easily fall prey to interventions that promise cures. These interventions may be harmful and, thus, pose one of the critical issues in special…

  2. Scandinavian object shift, remnant VP-topicalisation, verb particles and causatives

    DEFF Research Database (Denmark)

    Engels, Eva; Vikner, Sten


    constructions in Danish and Swedish, namely particle verb constructions and causative constructions with Danish "lade" and Swedish "låta" ‘let’. It is shown how differences in the VP-internal object position give rise to mirror image sequences concerning Object Shift in connection with verb second (Vº...

  3. Causation and Effectuation Processes: Opportunity Discovery and Exploitation Logics of Habitual Entrepreneurs

    DEFF Research Database (Denmark)

    Müller, Sabine


    This study investigates how habitual entrepreneurs (i.e. serial and portfolio entrepreneurs) discover and exploit opportunities, deal with risk and uncertainty, predict or control the future, and plan their businesses based on a causation and effectuation perspective. This study thereby uncovered...

  4. 76 FR 15268 - Guidelines for Determining Probability of Causation Under the Energy Employees Occupational... (United States)


    ... radioepidemiological tables (or its successor) in computing probability of causation. The Act further requires that the...; \\36\\ the NIOSH Annotated Bibliography for CLL; \\37\\ the CLL special issue of the British Journal of.... population \\40\\ and from the International Agency for Research on Cancer (IARC) databases for the...

  5. Strategy for incorporating newly discovered causative genetic variants into genomic evaluations (United States)

    With sequence data available for an increasing number of dairy cattle, discovery of causative genetic variants is expected to be frequent. Current genomic evaluation systems require genotypes for all markers that contribute to an evaluation. A minimum number of animals with an observation for a new ...

  6. Functional characterization of two paralogs that are novel RNA binding proteins influencing mitochondrial transcripts of Trypanosoma brucei. (United States)

    Kafková, Lucie; Ammerman, Michelle L; Faktorová, Drahomíra; Fisk, John C; Zimmer, Sara L; Sobotka, Roman; Read, Laurie K; Lukes, Julius; Hashimi, Hassan


    A majority of Trypanosoma brucei proteins have unknown functions, a consequence of its independent evolutionary history within the order Kinetoplastida that allowed for the emergence of several unique biological properties. Among these is RNA editing, needed for expression of mitochondrial-encoded genes. The recently discovered mitochondrial RNA binding complex 1 (MRB1) is composed of proteins with several functions in processing organellar RNA. We characterize two MRB1 subunits, referred to herein as MRB8170 and MRB4160, which are paralogs arisen from a large chromosome duplication occurring only in T. brucei. As with many other MRB1 proteins, both have no recognizable domains, motifs, or orthologs outside the order. We show that they are both novel RNA binding proteins, possibly representing a new class of these proteins. They associate with a similar subset of MRB1 subunits but not directly with each other. We generated cell lines that either individually or simultaneously target the mRNAs encoding both proteins using RNAi. Their dual silencing results in a differential effect on moderately and pan-edited RNAs, suggesting a possible functional separation of the two proteins. Cell growth persists upon RNAi silencing of each protein individually in contrast to the dual knockdown. Yet, their apparent redundancy in terms of cell viability is at odds with the finding that only one of these knockdowns results in the general degradation of pan-edited RNAs. While MRB8170 and MRB4160 share a considerable degree of conservation, our results suggest that their recent sequence divergence has led to them influencing mitochondrial mRNAs to differing degrees.

  7. Regulators of Trypanosoma brucei cell cycle progression and differentiation identified using a kinome-wide RNAi screen.

    Directory of Open Access Journals (Sweden)

    Nathaniel G Jones


    Full Text Available The African trypanosome, Trypanosoma brucei, maintains an integral link between cell cycle regulation and differentiation during its intricate life cycle. Whilst extensive changes in phosphorylation have been documented between the mammalian bloodstream form and the insect procyclic form, relatively little is known about the parasite's protein kinases (PKs involved in the control of cellular proliferation and differentiation. To address this, a T. brucei kinome-wide RNAi cell line library was generated, allowing independent inducible knockdown of each of the parasite's 190 predicted protein kinases. Screening of this library using a cell viability assay identified ≥42 PKs that are required for normal bloodstream form proliferation in culture. A secondary screen identified 24 PKs whose RNAi-mediated depletion resulted in a variety of cell cycle defects including in G1/S, kinetoplast replication/segregation, mitosis and cytokinesis, 15 of which are novel cell cycle regulators. A further screen identified for the first time two PKs, named repressor of differentiation kinase (RDK1 and RDK2, depletion of which promoted bloodstream to procyclic form differentiation. RDK1 is a membrane-associated STE11-like PK, whilst RDK2 is a NEK PK that is essential for parasite proliferation. RDK1 acts in conjunction with the PTP1/PIP39 phosphatase cascade to block uncontrolled bloodstream to procyclic form differentiation, whilst RDK2 is a PK whose depletion efficiently induces differentiation in the absence of known triggers. Thus, the RNAi kinome library provides a valuable asset for functional analysis of cell signalling pathways in African trypanosomes as well as drug target identification and validation.

  8. The orthologue of Sjogren's syndrome nuclear autoantigen 1 (SSNA1 in Trypanosoma brucei is an immunogenic self-assembling molecule.

    Directory of Open Access Journals (Sweden)

    Helen P Price

    Full Text Available Primary Sjögren's Syndrome (PSS is a highly prevalent autoimmune disease, typically manifesting as lymphocytic infiltration of the exocrine glands leading to chronically impaired lacrimal and salivary secretion. Sjögren's Syndrome nuclear autoantigen 1 (SSNA1 or NA14 is a major specific target for autoantibodies in PSS but the precise function and clinical relevance of this protein are largely unknown. Orthologues of the gene are absent from many of the commonly used model organisms but are present in Chlamyodomonas reinhardtii (in which it has been termed DIP13 and most protozoa. We report the functional characterisation of the orthologue of SSNA1 in the kinetoplastid parasite, Trypanosoma brucei. Both TbDIP13 and human SSNA1 are small coiled-coil proteins which are predicted to be remote homologues of the actin-binding protein tropomyosin. We use comparative proteomic methods to identify potential interacting partners of TbDIP13. We also show evidence that TbDIP13 is able to self-assemble into fibril-like structures both in vitro and in vivo, a property which may contribute to its immunogenicity. Endogenous TbDIP13 partially co-localises with acetylated α-tubulin in the insect procyclic stage of the parasite. However, deletion of the DIP13 gene in cultured bloodstream and procyclic stages of T. brucei has little effect on parasite growth or morphology, indicating either a degree of functional redundancy or a function in an alternative stage of the parasite life cycle.

  9. Crystal Structures of TbCatB and rhodesain, potential chemotherapeutic targets and major cysteine proteases of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Iain D Kerr

    Full Text Available BACKGROUND: Trypanosoma brucei is the etiological agent of Human African Trypanosomiasis, an endemic parasitic disease of sub-Saharan Africa. TbCatB and rhodesain are the sole Clan CA papain-like cysteine proteases produced by the parasite during infection of the mammalian host and are implicated in the progression of disease. Of considerable interest is the exploration of these two enzymes as targets for cysteine protease inhibitors that are effective against T. brucei. METHODS AND FINDINGS: We have determined, by X-ray crystallography, the first reported structure of TbCatB in complex with the cathepsin B selective inhibitor CA074. In addition we report the structure of rhodesain in complex with the vinyl-sulfone K11002. CONCLUSIONS: The mature domain of our TbCat*CA074 structure contains unique features for a cathepsin B-like enzyme including an elongated N-terminus extending 16 residues past the predicted maturation cleavage site. N-terminal Edman sequencing reveals an even longer extension than is observed amongst the ordered portions of the crystal structure. The TbCat*CA074 structure confirms that the occluding loop, which is an essential part of the substrate-binding site, creates a larger prime side pocket in the active site cleft than is found in mammalian cathepsin B-small molecule structures. Our data further highlight enhanced flexibility in the occluding loop main chain and structural deviations from mammalian cathepsin B enzymes that may affect activity and inhibitor design. Comparisons with the rhodesain*K11002 structure highlight key differences that may impact the design of cysteine protease inhibitors as anti-trypanosomal drugs.

  10. Trypanosoma brucei PUF9 regulates mRNAs for proteins involved in replicative processes over the cell cycle.

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    Stuart K Archer


    Full Text Available Many genes that are required at specific points in the cell cycle exhibit cell cycle-dependent expression. In the early-diverging model eukaryote and important human pathogen Trypanosoma brucei, regulation of gene expression in the cell cycle and other processes is almost entirely post-transcriptional. Here, we show that the T. brucei RNA-binding protein PUF9 stabilizes certain transcripts during S-phase. Target transcripts of PUF9--LIGKA, PNT1 and PNT2--were identified by affinity purification with TAP-tagged PUF9. RNAi against PUF9 caused an accumulation of cells in G2/M phase and unexpectedly destabilized the PUF9 target mRNAs, despite the fact that most known Puf-domain proteins promote degradation of their target mRNAs. The levels of the PUF9-regulated transcripts were cell cycle dependent, peaking in mid- to late- S-phase, and this effect was abolished when PUF9 was targeted by RNAi. The sequence UUGUACC was over-represented in the 3' UTRs of PUF9 targets; a point mutation in this motif abolished PUF9-dependent stabilization of a reporter transcript carrying the PNT1 3' UTR. LIGKA is involved in replication of the kinetoplast, and here we show that PNT1 is also kinetoplast-associated and its over-expression causes kinetoplast-related defects, while PNT2 is localized to the nucleus in G1 phase and redistributes to the mitotic spindle during mitosis. PUF9 targets may constitute a post-transcriptional regulon, encoding proteins involved in temporally coordinated replicative processes in early G2 phase.

  11. Bisphosphonates inhibit the growth of Trypanosoma brucei, Trypanosoma cruzi, Leishmania donovani, Toxoplasma gondii, and Plasmodium falciparum: a potential route to chemotherapy. (United States)

    Martin, M B; Grimley, J S; Lewis, J C; Heath, H T; Bailey, B N; Kendrick, H; Yardley, V; Caldera, A; Lira, R; Urbina, J A; Moreno, S N; Docampo, R; Croft, S L; Oldfield, E


    We have investigated the effects in vitro of a series of bisphosphonates on the proliferation of Trypanosoma cruzi, Trypanosoma brucei rhodesiense, Leishmania donovani, Toxoplasma gondii, and Plasmodium falciparum. The results show that nitrogen-containing bisphosphonates of the type used in bone resorption therapy have significant activity against parasites, with the aromatic species having in some cases nanomolar or low-micromolar IC(50) activity values against parasite replication (e.g. o-risedronate, IC(50) = 220 nM for T. brucei rhodesiense; risedronate, IC(50) = 490 nM for T. gondii). In T. cruzi, the nitrogen-containing bisphosphonate risedronate is shown to inhibit sterol biosynthesis at a pre-squalene level, most likely by inhibiting farnesylpyrophosphate synthase. Bisphosphonates therefore appear to have potential in treating parasitic protozoan diseases.

  12. Effect of experimental single Ancylostoma caninum and mixed infections of Trypanosoma brucei and Trypanosoma congolense on the humoural immune response to anti-rabies vaccination in dogs

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Anene Boniface Maduka


    Objective:To determine the effect of Ancylostoma caninum (A. caninum) and trypanosome parasites on the immune response to vaccination in dogs in endemic environments. Methods:Sixteen dogs for the experiment were grouped into 4 of 4 members each. Group I was the uninfected control one, and GPII was infected with A. caninum; GPIII was infected with A. caninum/Trypanosoma congolense (T. congolense), and GPIV was infected with Trypanosoma brucei (T. brucei)/A. caninum. The dogs were first vaccinated with antirabies vaccine before infecting GPII, GPIII and GPIV with A. caninum which were done 4 weeks after vaccination. By 2-week post-vaccination, trypanosome parasites were superimposed on both GPIII and GPIV. A secondary vaccination was given to GPI, GPII, GPIII, and GPIV by Week 12 of the experiment (4 weeks post treatment). Results:The prepatent period was (3.00 ± 1.40) days, in the conjunct infection of T. brucei/A. caninum. It was (9.00 ± 1.10) days, in conjunct T. congolense/A. caninum. The prepatent period of A. caninum was (14.0 ± 2.0) days in the single A. caninum group and (13.0 ± 1.0) days in the conjunct trypanosome/A. caninum. At the 1st week after vaccination, the antibody titer in all the vaccinated groups (GPI, GPII, GPIII, and GPIV) significantly increased (P Conclusions:It was therefore concluded that A. caninum, T. brucei and T. congolense induced immunosuppression in antirabies vaccination in dogs.

  13. Parasite-based screening and proteome profiling reveal orlistat, an FDA-approved drug, as a potential anti Trypanosoma brucei agent. (United States)

    Yang, Peng-Yu; Wang, Min; Liu, Kai; Ngai, Mun Hong; Sheriff, Omar; Lear, Martin J; Sze, Siu Kwan; He, Cynthia Y; Yao, Shao Q


    Trypanosoma brucei is a parasite that causes African sleeping sickness in humans and nagana in livestock and is transmitted by the tsetse fly. There is an urgent need for the development of new drugs against African trypanosomiasis due to the lack of vaccines and effective drugs. Orlistat (also called tetrahydrolipstatin or THL) is an FDA-approved antiobesity drug targeting primarily the pancreatic and gastric lipases within the gastrointestinal tract. It shows potential activities against tumors, mycobacteria, and parasites. Herein, we report the synthesis and evaluation of an expanded set of orlistat-like compounds, some of which showed highly potent trypanocidal activities in both the bloodstream form (BSF) and the procyclic form (PCF) of T. brucei. Subsequent in situ parasite-based proteome profiling was carried out to elucidate potential cellular targets of the drug in both forms. Some newly identified targets were further validated by the labeling of recombinantly expressed enzymes in Escherichia coli lysates. Bioimaging experiments with a selected compound were carried out to study the cellular uptake of the drug in T. brucei. Results indicated that orlistat is much more efficiently taken up by the BSF than the PCF of T. brucei and has clear effects on the morphology of mitochondria, glycosomes, and the endoplasmic reticulum in both BSF and PCF cells. These results support specific effects of orlistat on these organelles and correlate well with our in situ proteome profiling. Given the economic challenges of de novo drug development for neglected diseases, we hope that our findings will stimulate further research towards the conversion of orlistat-like compounds into new trypanocidal drugs.

  14. Comparative analysis of the kinomes of three pathogenic trypanosomatids: Leishmania major, Trypanosoma brucei and Trypanosoma cruzi


    Ward Pauline N; Worthey Elizabeth A; Parsons Marilyn; Mottram Jeremy C


    Abstract Background The trypanosomatids Leishmania major, Trypanosoma brucei and Trypanosoma cruzi cause some of the most debilitating diseases of humankind: cutaneous leishmaniasis, African sleeping sickness, and Chagas disease. These protozoa possess complex life cycles that involve development in mammalian and insect hosts, and a tightly coordinated cell cycle ensures propagation of the highly polarized cells. However, the ways in which the parasites respond to their environment and coordi...

  15. Vulvovaginal candidiasis in Mato Grosso, Brazil: pregnancy status, causative species and drugs tests

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    Luciana Basili Dias


    Full Text Available Causative agent in majority of VVC is Candida albicans, but infection due to non-C. albicans is common. Use of empiric antifungal therapy in Brazil due to syndromic management of vulvovaginitis could act as risk factor for increase resistance among VVC causative agents. From Mato Grosso patients, 160 with culture-proved among 404 women who had clinical symptoms of VVC, were enrolled in this study. 70 non-pregnant women and 90 pregnant women were included. Candida albicans was the most prevalent, representing 72.9% in the non-pregnant group and 92.3% in the pregnant group. Differences in species distribution were noted between the two groups, being C. parapsilosis the second more prevalent species among non-pregnant women. Susceptibility testing revealed high susceptibility to fluconazole (except for C. krusei, itraconazole, ketoconazole, and amphotericin B regardless the species (C. albicans, C. parapsilosis, C. tropicalis, C. glabrata, C. krusei analyzed.

  16. A selective overview of issues on classification, causation, and early intensive behavioral intervention for autism. (United States)

    Pelios, L V; Lund, S K


    Autism is a behaviorally defined disorder that comprises a controversial diagnostic category due to heterogeneity in symptomatology, causation, and etiology and significant variance in response to intervention. In this article, the authors provide a brief overview of the clinical category and a summary of diagnostic developments with respect to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders. Regarding causation and etiology, they briefly discuss selected perspectives from the fields of cognitive neuroscience and neuropsychology. The article concludes with a summary of effective behavioral strategies for the treatment of children with autism. This section highlights the importance of early intensive behavioral intervention and includes a discussion of some important aspects of this approach.

  17. Causation and prediction in epidemiology: a guide to the "methodological revolution". (United States)

    Broadbent, Alex


    There is an ongoing "methodological revolution" in epidemiology, according to some commentators. The revolution is prompted by the development of a conceptual framework for thinking about causation here referred to as the Potential Outcomes Approach (POA), and the mathematical apparatus of directed acyclic graphs that accompanies it. But over and above the mathematics, a number of striking theses about causation are evident, for example: that a cause is something that makes a difference; that a cause is something that humans can intervene on; and that causal knowledge enables one to predict under hypothetical suppositions. This is especially remarkable in a discipline that has variously identified factors such as race and sex as determinants of health, since it has the consequence that factors of this kind cannot be treated as causes either as usefully or as meaningfully as was previously supposed. In this paper I seek to explain the significance of this movement in epidemiology, to understand its commitments, and to evaluate them.

  18. Are All Children Equal? Causative Factors of Child Labour in Selected Districts of South Punjab, Pakistan

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    Syed Zubair Haider


    Full Text Available The present study investigates the causative factors of child labour in selected districts of South Punjab, Pakistan. As member of the International Labour Organization (ILO Pakistan has a responsibility to stamp out child labour from its regions. Our sample was selected from seven working environments (workshops, hotels, tea stalls, households, etc. through purposive sampling. The data were collected via a questionnaire which was completed by a sample of 547 working children. The findings of the exploratory factor analysis (EFA explored four factors from the research. Multilevel analyses were calculated to pinpoint the causative factors of child labour. The study results revealed that, due to family responsibilities, a lack of educational opportunities for children from low-income families, and increasing poverty, children develop an interest in working to earn their livelihood at the cost of their education. The children are involved in labour because their parents cannot meet their personal and educational requirements.

  19. [Some properties of plasmocoagulase of the causative agents of glanders and melioidosis]. (United States)

    Narbutovich, N I; Lomova, L V; Ageeva, N P; Kucheriaeva, V T; Seimova, I K


    Criteria for the evaluation of the plasmocoagulase activity of natural isolates and mutant strains of the causative agents of glanders and melioidosis were worked out, which made it possible to subdivide them by this sign into pathogens with high, moderate and low activity. Plasmocoagulase produced by pathogenic Burkholderia was shown to be a thermolabile enzyme, comparatively stable with respect to the action of such chemico-biological agents as hydrogen peroxide and chloramine.

  20. Occlusion as a causative factor in TMD. Scientific basis to occlusal therapy. (United States)

    Becker, I M


    There appears to be a pendulum swing toward large epidemiologic studies questioning the role of occlusion in dentistry. This article clearly demonstrates that significant scientific evidence exists on the side of occlusal causative factors. Clinicians need this current information to base practical decisions of treatment relative to both patients and those requiring restorative procedures. It further correctly clarifies that stress-related issues have an important role, along with other host-susceptibility altering factors.

  1. Frequency of sexual dysfunction and its causative factors among diabetic women in Turkey


    Duman, Nuriye Buyukkayaci


    Objective: To determine the frequency of sexual dysfunction and its causative factors among the diabetic women. Methods: The sample of the research was made up of 200 diabetic women selected using simple-random sampling who went to endocrinology poly clinics for counseling and treatment. The data were gathered with Data Collection Form for Women’s Descriptive Characteristics designed by the researchers using the information in literature, Female Sexual Function Index and Beck Depression Inven...

  2. Decadal trends in beach morphology on the east coast of South Africa and likely causative factors

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    S. Corbella


    Full Text Available Sandy shorelines are dynamic with constant changes that can cause hazards in developed areas. The causes of change may be either natural or anthropogenic. This paper evaluates evidence for shoreline changes and their causative factors using a case study on the east coast of South Africa. Beach morphology trends were found to be location-specific, but overall the beaches show a receding trend. It was hypothesized that wave, tide, sea level and wind trends as well as anthropogenic influences are causative factors, and their contributions to shoreline changes were evaluated. Maximum significant wave heights, average wave direction, peak period and storm event frequencies all show weak increasing trends, but only the increases in peak period and wave direction are statistically significant. The chronic beach erosion cannot be attributed to wave climate changes since they are still too small to explain the observations. Instead, the impacts of sea level rise and reductions in the supply of beach sediments are suggested as the main causative factors. The analysis also identifies a trend in the frequency of severe erosion events due to storms that coincide with a 4.5-yr extreme tide cycle, which demonstrates the potential impact of future sea level rise.

  3. Alba-domain proteins of Trypanosoma brucei are cytoplasmic RNA-binding proteins that interact with the translation machinery.

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    Jan Mani

    Full Text Available Trypanosoma brucei and related pathogens transcribe most genes as polycistronic arrays that are subsequently processed into monocistronic mRNAs. Expression is frequently regulated post-transcriptionally by cis-acting elements in the untranslated regions (UTRs. GPEET and EP procyclins are the major surface proteins of procyclic (insect midgut forms of T. brucei. Three regulatory elements common to the 3' UTRs of both mRNAs regulate mRNA turnover and translation. The glycerol-responsive element (GRE is unique to the GPEET 3' UTR and regulates its expression independently from EP. A synthetic RNA encompassing the GRE showed robust sequence-specific interactions with cytoplasmic proteins in electromobility shift assays. This, combined with column chromatography, led to the identification of 3 Alba-domain proteins. RNAi against Alba3 caused a growth phenotype and reduced the levels of Alba1 and Alba2 proteins, indicative of interactions between family members. Tandem-affinity purification and co-immunoprecipitation verified these interactions and also identified Alba4 in sub-stoichiometric amounts. Alba proteins are cytoplasmic and are recruited to starvation granules together with poly(A RNA. Concomitant depletion of all four Alba proteins by RNAi specifically reduced translation of a reporter transcript flanked by the GPEET 3' UTR. Pulldown of tagged Alba proteins confirmed interactions with poly(A binding proteins, ribosomal protein P0 and, in the case of Alba3, the cap-binding protein eIF4E4. In addition, Alba2 and Alba3 partially cosediment with polyribosomes in sucrose gradients. Alba-domain proteins seem to have exhibited great functional plasticity in the course of evolution. First identified as DNA-binding proteins in Archaea, then in association with nuclear RNase MRP/P in yeast and mammalian cells, they were recently described as components of a translationally silent complex containing stage-regulated mRNAs in Plasmodium. Our results are

  4. Probing the metabolic network in bloodstream-form Trypanosoma brucei using untargeted metabolomics with stable isotope labelled glucose.

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    Darren J Creek


    Full Text Available Metabolomics coupled with heavy-atom isotope-labelled glucose has been used to probe the metabolic pathways active in cultured bloodstream form trypomastigotes of Trypanosoma brucei, a parasite responsible for human African trypanosomiasis. Glucose enters many branches of metabolism beyond glycolysis, which has been widely held to be the sole route of glucose metabolism. Whilst pyruvate is the major end-product of glucose catabolism, its transamination product, alanine, is also produced in significant quantities. The oxidative branch of the pentose phosphate pathway is operative, although the non-oxidative branch is not. Ribose 5-phosphate generated through this pathway distributes widely into nucleotide synthesis and other branches of metabolism. Acetate, derived from glucose, is found associated with a range of acetylated amino acids and, to a lesser extent, fatty acids; while labelled glycerol is found in many glycerophospholipids. Glucose also enters inositol and several sugar nucleotides that serve as precursors to macromolecule biosynthesis. Although a Krebs cycle is not operative, malate, fumarate and succinate, primarily labelled in three carbons, were present, indicating an origin from phosphoenolpyruvate via oxaloacetate. Interestingly, the enzyme responsible for conversion of phosphoenolpyruvate to oxaloacetate, phosphoenolpyruvate carboxykinase, was shown to be essential to the bloodstream form trypanosomes, as demonstrated by the lethal phenotype induced by RNAi-mediated downregulation of its expression. In addition, glucose derivatives enter pyrimidine biosynthesis via oxaloacetate as a precursor to aspartate and orotate.

  5. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets.

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    Susan T Mashiyama

    Full Text Available We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups ("M32" and "C51" that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at

  6. Causative Mechanisms of Tropical (10°N-15°N) Mesospheric Inversion Layers (United States)

    Ramesh, Karanam; Sundararajan, Sridharan; Vijaya Bhaskara Rao, S.


    The inversion of temperature gradient from negative to positive superimposed upon the characteristically decreasing mesospheric thermal structure is known as Mesospheric Inversion Layer (MIL). Gravity wave breaking, planetary wave critical level interaction and the chemical heating have been suggested as potential causative mechanisms for the occurrence of the MILs. Although the morphological characteristics of MIL have been studied in detail at different sites using various instrumental techniques, their causative mechanisms are still unknown. In the present study, nearly all these major causative mechanisms have been addressed through a few case studies observed from Rayleigh lidar and TIMED-SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics - Sounding of Atmosphere by Broadband Emission Radiometry) nightly temperatures over a tropical site, Gadanki (13.5°N,79.2°E). A few large MILs are observed above ˜80 km with amplitude and thickness of ˜50 K and ˜5 km respectively in 2007 and 2011 which are found to be predominantly due to gravity wave breaking and large chemical heating rate (˜15 K/day) by the exothermic reaction, H+O _{3}->OH+O _{2} respectively. It is also found that the SABER shows larger ozone (O _{3}) mixing ratios at the inversion heights (˜80-85 km) during the MIL events in 2011. In another special case study, a triple layered MIL event with three inversion layers at ˜70 km (˜11 K), 80 km (˜44 K), 90 km (˜109 K) has been observed in September 2011 over Gadanki region. It is found that these three inversion layers are respectively due to planetary wave breaking, gravity wave tidal interaction and chemical heating by the reaction, O+O+M->O _{2}+M.

  7. A case of sinobronchial allergic mycosis; possibility of basidiomycetous fungi as a causative antigen. (United States)

    Ogawa, Haruhiko; Fujimura, Masaki; Takeuchi, Yasuo; Makimura, Koichi


    We herein report a case of sinobronchial allergic mycosis (SAM) caused by basidiomycetous (BM) fungi (probably Phanerochaete velutina). The patient with bronchial asthma that accompanied allergic fungal sinusitis (AFS) fulfilled all 6 criteria for diagnosing SAM. In this case, the BM fungus may act as an allergen, reacting continually in both the upper and lower respiratory tract. The antifungal drug (itraconazole 50 mg/day) seemed to achieve a partial response. Basidiomycetous fungi may attract attention because of the possibility as a causative antigen in this new clinical concept of SAM.

  8. [Molecular-genetic approaches to diagnosis and intraspecific typing of causative agents of glanders and melioidosis]. (United States)

    Antonov, V A; Iliukhin, V I


    Pathogenic Burkholderia--Burkholderia mallei and Burkholderia pseudomallei--are causative agents of glanders and melioidosis, severe infectious diseases of man and animals. They are regarded as potential agents of bioterrorism. The existing bacteriological and immunological methods of identification of B. mallei and B. pseudomallei are not efficient enough for the rapid diagnosis and typing of strains. Described in the paper are molecular methods of detection of the agents by PCR, hybridization and strain typing made on the basis of bacterial total cell protein profiles, RAPD, ribotyping as well as of plasmid and DNA microrestriction analyses.

  9. [Identification of the causative agents of glanders and melioidosis by polymerase chain reaction]. (United States)

    Tkachenko, G A; Antonov, V A; Zamaraev, V S; Iliukhin, V I


    Burkholderia mallei and B. pseudomallei are causative agents of glanders and melioidosis, respectively, i.e. severe and fatal infection diseases of man and animal. The computer-based analysis of the 23S rRNA gene sites was used for selecting the primers. Two pairs of primers were chosen for the identification of B. mallei and Bpseudomallei. DNAs from 48 B. pseudomallei and 15 strains of B. mallei, unlike from other geterological bacteria, were positively amplified. Therefore, the method of polymerase chain reaction can be used in laboratory diagnosis of glanders and melioidosis.

  10. Identification of the causative agent of cutaneous leishmaniasis in Chichaoua province, Morocco

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    Rhajaoui M.


    Full Text Available Cutaneous leishmaniasis (CL in Morocco is caused by three species, Leishmania major, L. tropica and L. infantum. CL has been known in Chichaoua province since 2000. Using DNA extracted from microscopic slides and parasite cultures, collected in the years 2006 and 2009, we identified for the first time L. tropica as the causative agent of CL in this region. Species identification was achieved by performing the ITS1-PCR-RFLP approach. By using this method it was possible to identify parasites in Giemsa stained slides containing less than five parasites per oil-immersion field even they were conserved for up to four months.

  11. Burkholderia mallei and Burkholderia pseudomallei: the causative micro-organisms of glanders and melioidosis. (United States)

    Gilad, Jacob


    Burkholderia mallei and Burkholderia pseudomallei are the causative micro-organisms of Glanders and Melioidosis, respectively. Although now rare in Western countries, both micro-organisms have recently gained much interest because of their unique potential as bioterrorism agents. This paper reviews the epidemiology, pathogenesis, diagnosis and treatment of Melioidosis and Glanders. Recent patents relating to these micro-organisms, especially potential vaccines, are presented. Continued research and development is urgently needed, especially in regard to rapid and accurate diagnosis of melioidosis and glanders, efficacious therapy and primary and secondary prevention.

  12. Text-analytic Measurement of Effectuation and Causation Orientations among Small and Global Business Managers

    DEFF Research Database (Denmark)

    Mattsson, Jan; Helmersson, Helge


    We demonstrate how one can measure overall quality in texts gathered from interviews by means of PERTEX text analytic method. We compare text analytic measures and content for locally active Scandinavian small business managers and globally operating Indian IT managers when recapitulating......-components we are also able to display the degree of fragmentation, focus and integration in the text. We show how AFFI measures differ between managers with a causation or effectuation orientation irrespective of their role as small business manager or as an established global manager. Hence, we posit...

  13. Morganella morganii , subspecies morganii, biogroup A: An unusual causative pathogen of brain abscess

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    Asha B Patil


    Full Text Available Morganella morganii is a gram negative aerobe , found often as intestinal commensal. It is commonly implicated in Urinary tract infections and pyogenic infections, but rarely causes CNS infections especially brain abscess. There are very few published reports of Morganella morganii as a causative pathogen in brain abscess. High index of suspicion of this pathogen is important in cases of brain abscess secondary to otogenic infections. This paper reports an unusual case of Morganella morganii, subspecies morganii, biogroup A Brain abscess .The paper also reviews other infections caused by Morganell morganii.

  14. Morganella morganii, subspecies morganii, biogroup A: An unusual causative pathogen of brain abscess. (United States)

    Patil, Asha B; Nadagir, Shobha D; Lakshminarayana, Sa; Syeda, Fasiha M


    Morganella morganii is a gram negative aerobe , found often as intestinal commensal. It is commonly implicated in Urinary tract infections and pyogenic infections, but rarely causes CNS infections especially brain abscess. There are very few published reports of Morganella morganii as a causative pathogen in brain abscess. High index of suspicion of this pathogen is important in cases of brain abscess secondary to otogenic infections. This paper reports an unusual case of Morganella morganii, subspecies morganii, biogroup A Brain abscess. The paper also reviews other infections caused by Morganell morganii.

  15. Metal-dependent gene regulation in the causative agent of Lyme disease



    Borrelia burgdorferi (Bb) is the causative agent of Lyme disease transmitted to humans by ticks of the Ixodes spp. Bb is a unique bacterial pathogen because it does not require iron (Fe2+) for its metabolism. Bb encodes a ferritin-like Dps homolog called NapA (also called BicA), which can bind Fe or copper (Cu2+), and a manganese (Mn2+) transport protein, Borrelia metal transporter A (BmtA); both proteins are required for colonization of the tick vector, but BmtA is also required for the muri...

  16. "Are we there yet?": Deciding when one has demonstrated specific genetic causation in complex diseases and quantitative traits. (United States)

    Page, Grier P; George, Varghese; Go, Rodney C; Page, Patricia Z; Allison, David B


    Although mathematical relationships can be proven by deductive logic, biological relationships can only be inferred from empirical observations. This is a distinct disadvantage for those of us who strive to identify the genes involved in complex diseases and quantitative traits. If causation cannot be proven, however, what does constitute sufficient evidence for causation? The philosopher Karl Popper said, "Our belief in a hypothesis can have no stronger basis than our repeated unsuccessful critical attempts to refute it." We believe that to establish causation, as scientists, we must make a serious attempt to refute our own hypotheses and to eliminate all known sources of bias before association becomes causation. In addition, we suggest that investigators must provide sufficient data and evidence of their unsuccessful efforts to find any confounding biases. In this editorial, we discuss what "causation" means in the context of complex diseases and quantitative traits, and we suggest guidelines for steps that may be taken to address possible confounders of association before polymorphisms may be called "causative."

  17. Histone H3 Variant Regulates RNA Polymerase II Transcription Termination and Dual Strand Transcription of siRNA Loci in Trypanosoma brucei.

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    David Reynolds


    Full Text Available Base J, β-D-glucosyl-hydroxymethyluracil, is a chromatin modification of thymine in the nuclear DNA of flagellated protozoa of the order Kinetoplastida. In Trypanosoma brucei, J is enriched, along with histone H3 variant (H3.V, at sites involved in RNA Polymerase (RNAP II termination and telomeric sites involved in regulating variant surface glycoprotein gene (VSG transcription by RNAP I. Reduction of J in T. brucei indicated a role of J in the regulation of RNAP II termination, where the loss of J at specific sites within polycistronic gene clusters led to read-through transcription and increased expression of downstream genes. We now demonstrate that the loss of H3.V leads to similar defects in RNAP II termination within gene clusters and increased expression of downstream genes. Gene derepression is intensified upon the subsequent loss of J in the H3.V knockout. mRNA-seq indicates gene derepression includes VSG genes within the silent RNAP I transcribed telomeric gene clusters, suggesting an important role for H3.V in telomeric gene repression and antigenic variation. Furthermore, the loss of H3.V at regions of overlapping transcription at the end of convergent gene clusters leads to increased nascent RNA and siRNA production. Our results suggest base J and H3.V can act independently as well as synergistically to regulate transcription termination and expression of coding and non-coding RNAs in T. brucei, depending on chromatin context (and transcribing polymerase. As such these studies provide the first direct evidence for histone H3.V negatively influencing transcription elongation to promote termination.

  18. Trypanosoma brucei Invasion and T-Cell Infiltration of the Brain Parenchyma in Experimental Sleeping Sickness: Timing and Correlation with Functional Changes (United States)

    Laperchia, Claudia; Palomba, Maria; Seke Etet, Paul F.; Rodgers, Jean; Bradley, Barbara; Montague, Paul; Grassi-Zucconi, Gigliola; Bentivoglio, Marina


    Background The timing of Trypanosoma brucei entry into the brain parenchyma to initiate the second, meningoencephalitic stage of human African trypanosomiasis or sleeping sickness is currently debated and even parasite invasion of the neuropil has been recently questioned. Furthermore, the relationship between neurological features and disease stage are unclear, despite the important diagnostic and therapeutic implications. Methodology Using a rat model of chronic Trypanosoma brucei brucei infection we determined the timing of parasite and T-cell neuropil infiltration and its correlation with functional changes. Parasite DNA was detected using trypanosome-specific PCR. Body weight and sleep structure alterations represented by sleep-onset rapid eye movement (SOREM) periods, reported in human and experimental African trypanosomiasis, were monitored. The presence of parasites, as well as CD4+ and CD8+ T-cells in the neuropil was assessed over time in the brain of the same animals by immunocytochemistry and quantitative analyses. Principal findings Trypanosome DNA was present in the brain at day 6 post-infection and increased more than 15-fold by day 21. Parasites and T-cells were observed in the parenchyma from day 9 onwards. Parasites traversing blood vessel walls were observed in the hypothalamus and other brain regions. Body weight gain was reduced from day 7 onwards. SOREM episodes started in most cases early after infection, with an increase in number and duration after parasite neuroinvasion. Conclusion These findings demonstrate invasion of the neuropil over time, after an initial interval, by parasites and lymphocytes crossing the blood-brain barrier, and show that neurological features can precede this event. The data thus challenge the current clinical and cerebrospinal fluid criteria of disease staging. PMID:28002454

  19. Attribution of intentional causation influences the perception of observed movements: Behavioural evidence and neural correlates

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    James W Moore


    Full Text Available Recent research on human agency suggests that intentional causation is associated with a subjective compression in the temporal interval between actions and their effects. That is, intentional movements and their causal effects are perceived as closer together in time than equivalent unintentional movements and their causal effects. This so-called intentional binding effect is consistently found for one’s own self-generated actions. It has also been suggested that intentional binding occurs when observing intentional movements of others. However, this evidence is undermined by limitations of the paradigm used. In the current study we aimed to overcome these limitations using a more rigorous design in combination with functional Magnetic Resonance Imaging (fMRI to explore the neural underpinnings of intentional binding of observed movements. In particular, we aimed to identify brain areas sensitive to the interaction between intentionality and causality attributed to the observed action. Our behavioural results confirmed the occurrence of intentional binding for observed movements using this more rigorous paradigm. Our fMRI results highlighted a collection of brain regions whose activity was sensitive to the interaction between intentionality and causation. Intriguingly, these brain regions have previously been implicated in the sense of agency over one’s own movements. We discuss the implications of these results for intentional binding specifically, and the sense of agency more generally.

  20. Identifying Coopted Networks and Causative Mutations in the Origin of Novel Complex Traits. (United States)

    Monteiro, A; Gupta, M D


    One of the central goals of the field of evo-devo is to understand how novel complex traits originate. Novel complex traits are often old, and this makes understanding the genetic basis of their origin difficult. The traditional genetics approach for identifying the causative mutations for trait origin, of crossing species with and without the trait, is often impossible when the species are too distantly related. Alternatively, if the species are closely related, the genetic basis of their differences is often the recent loss, rather than the gain, of the trait in one of them, and mutations resulting in trait loss are not always equivalent to those that led to trait gain. Here, we reexamine an evo-devo study of the origin of melanic spots in the wings of flies, which is presented in more than one mainstream undergraduate textbook on Evolution, as an example of molecular evolution leading to the origin of a novel trait. We put forth an alternative to the previously proposed scenario and, in our view, a more likely evolutionary framework that explains the data, the CRE-DDC model, and then review other case studies and avenues of research that should help identify where new complex traits come from, as well as the actual causative mutations underlying their origin.

  1. Septic Pulmonary Embolism Requiring Critical Care: Clinicoradiological Spectrum, Causative Pathogens and Outcomes

    Directory of Open Access Journals (Sweden)

    Deng-Wei Chou

    Full Text Available OBJECTIVES: Septic pulmonary embolism is an uncommon but life-threatening disorder. However, data on patients with septic pulmonary embolism who require critical care have not been well reported. This study elucidated the clinicoradiological spectrum, causative pathogens and outcomes of septic pulmonary embolism in patients requiring critical care. METHODS: The electronic medical records of 20 patients with septic pulmonary embolism who required intensive care unit admission between January 2005 and December 2013 were reviewed. RESULTS: Multiple organ dysfunction syndrome developed in 85% of the patients, and acute respiratory failure was the most common organ failure (75%. The most common computed tomographic findings included a feeding vessel sign (90%, peripheral nodules without cavities (80% or with cavities (65%, and peripheral wedge-shaped opacities (75%. The most common primary source of infection was liver abscess (40%, followed by pneumonia (25%. The two most frequent causative pathogens were Klebsiella pneumoniae (50% and Staphylococcus aureus (35%. Compared with survivors, nonsurvivors had significantly higher serum creatinine, arterial partial pressure of carbon dioxide, and Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores, and they were significantly more likely to have acute kidney injury, disseminated intravascular coagulation and lung abscesses. The in-hospital mortality rate was 30%. Pneumonia was the most common cause of death, followed by liver abscess. CONCLUSIONS: Patients with septic pulmonary embolism who require critical care, especially those with pneumonia and liver abscess, are associated with high mortality. Early diagnosis, appropriate antibiotic therapy, surgical intervention and respiratory support are essential.

  2. Recent trends in the distribution of causative diseases of fever of unknown origin. (United States)

    Shang, Jin; Yan, Libo; Du, Lingyao; Liang, Lingbo; Zhou, Qiaoling; Liang, Tao; Bai, Lang; Tang, Hong


    Fever of unknown origin is a challenging diagnostic problem and the aim of this research was to analyze trends in the distribution of its causative diseases. This retrospective study makes a comparison between two different clinical series of patients from two different periods: 227 from period 1 (1998-2002) and 602 from period 2 (2008-2012). There were fewer infections (31.72% vs.16.45%) and more miscellaneous causes (5.29% vs. 13.12%) in the period 2 series, whereas no significant differences in autoimmune diseases, malignancies and undiagnosed cases were found. Adult onset Still's disease and lymphoma occupied the largest proportion in autoimmune diseases (75.00%) and malignancies (89.81%), respectively. Interestingly, the autoimmune diseases group, instead of infections, was found to be the leading category of the causative diseases in fever of unknown origin, which is contrary to previous reports. Further, adult onset Still's disease and lymphoma were suggested to be valued more highly in view of the large and rising proportions found in this study. These trends could support the diagnosis and treatment of fever of unknown origin better in the future.

  3. Genetic screening of the inherited Ichtyosis causative mutation in Chianina cattle

    Directory of Open Access Journals (Sweden)

    Luciano Molteni


    Full Text Available Inherited Ichthyosis, Chianina, Causative mutation, Genetic screening.Inherited Ichthyosis is a genetic disorder reported in both humans and animals, including bovines. Two inherited forms were reported in cattle and both are transmitted in an autosomal recessive manner: Ichthyosis Fetalis (IF and Ichthyosis Congenita (IC. A causative mutation of IF in Chianina cattle was recently indentified in the ABC12 gene. This work reports the first genetic screening using this recently available genetic test on Chianina cattle. Tests were performed on both the population of farm breeding selected young bulls (131 samples randomly chosen and high breeding value sires (16 samples. Results confirm a low total prevalence of carriers in the selected sire population (2/131; 1.5% and the presence of the disease allele among the high value selected sires (1/16; 6.3%. This result strengthens the importance to continue the genetic screening program, particularly in performance tested bulls approved for use in AI or natural service.

  4. Environmentalist thinking and the question of disease causation in late Spanish Philippines. (United States)

    Reyes, Raquel A G


    The scientific understanding of disease causation was crucial to the ways in which the Spanish colonial state addressed epidemic diseases which periodically struck nineteenth-century Philippines. Scholars have often described Spanish colonial responses in terms of ineptitude and failure, and have often glossed over the multiple and competing scientific theories that preoccupied Spanish and Filipino physicians. This article examines the work and ideas of nineteenth-century Spanish colonial and patriotic Filipino physicians regarding disease causation in the tropical environment of the Philippines. It will focus on two key developments-Spanish environmentalist thinking and the emerging fields of microscopy and bacteriology. Much like the British and French colonialists, Spaniards viewed tropical climates as insalubrious and conducive to disease, perceiving themselves as constitutionally at risk in hot places, ill-suited, exposed, and vulnerable to so-called native diseases. By the 1880s, however, young Filipino researchers, some of whom had trained in Spain and France, were undertaking new research on polluted water, malaria, and cells. Influenced by the revolutionary new discoveries being made in bacteriology, these researchers questioned prevailing environmentalist explanations and focused, for the first time, on the nature of pathogens and microbial pathogenesis in disease development and transmission. But germ theory remained an idea among many. This article argues that although late nineteenth-century studies in microscopy by Filipinos slowly began to challenge Spanish colonial ideas, different streams of thinking overlapped and no single scientific explanation came to predominate.

  5. The genome sequence of Clostridium tetani, the causative agent of tetanus disease. (United States)

    Bruggemann, Holger; Baumer, Sebastian; Fricke, Wolfgang Florian; Wiezer, Arnim; Liesegang, Heiko; Decker, Iwona; Herzberg, Christina; Martinez-Arias, Rosa; Merkl, Rainer; Henne, Anke; Gottschalk, Gerhard


    Tetanus disease is one of the most dramatic and globally prevalent diseases of humans and vertebrate animals, and has been reported for over 24 centuries. The manifestation of the disease, spastic paralysis, is caused by the second most poisonous substance known, the tetanus toxin, with a human lethal dose of approximately 1 ng/kg. Fortunately, this disease is successfully controlled through immunization with tetanus toxoid; nevertheless, according to the World Health Organization, an estimated 400,000 cases still occur each year, mainly of neonatal tetanus. The causative agent of tetanus disease is Clostridium tetani, an anaerobic spore-forming bacterium, whose natural habitat is soil, dust, and intestinal tracts of various animals. Here we report the complete genome sequence of toxigenic C. tetani E88, a variant of strain Massachusetts. The genome consists of a 2,799,250-bp chromosome encoding 2,372 ORFs. The tetanus toxin and a collagenase are encoded on a 74,082-bp plasmid, containing 61 ORFs. Additional virulence-related factors could be identified, such as an array of surface-layer and adhesion proteins (35 ORFs), some of them unique to C. tetani. Comparative genomics with the genomes of Clostridium perfringens, the causative agent of gas gangrene, and Clostridium acetobutylicum, a nonpathogenic solvent producer, revealed a remarkable capacity of C. tetani: The organism can rely on an extensive sodium ion bioenergetics. Additional candidate genes involved in the establishment and maintenance of a pathogenic lifestyle of C. tetani are presented.

  6. Functional and structural insights revealed by molecular dynamics simulations of an essential RNA editing ligase in Trypanosoma brucei.

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    Rommie E Amaro

    Full Text Available RNA editing ligase 1 (TbREL1 is required for the survival of both the insect and bloodstream forms of Trypanosoma brucei, the parasite responsible for the devastating tropical disease African sleeping sickness. The type of RNA editing that TbREL1 is involved in is unique to the trypanosomes, and no close human homolog is known to exist. In addition, the high-resolution crystal structure revealed several unique features of the active site, making this enzyme a promising target for structure-based drug design. In this work, two 20 ns atomistic molecular dynamics (MD simulations are employed to investigate the dynamics of TbREL1, both with and without the ATP substrate present. The flexibility of the active site, dynamics of conserved residues and crystallized water molecules, and the interactions between TbREL1 and the ATP substrate are investigated and discussed in the context of TbREL1's function. Differences in local and global motion upon ATP binding suggest that two peripheral loops, unique to the trypanosomes, may be involved in interdomain signaling events. Notably, a significant structural rearrangement of the enzyme's active site occurs during the apo simulations, opening an additional cavity adjacent to the ATP binding site that could be exploited in the development of effective inhibitors directed against this protozoan parasite. Finally, ensemble averaged electrostatics calculations over the MD simulations reveal a novel putative RNA binding site, a discovery that has previously eluded scientists. Ultimately, we use the insights gained through the MD simulations to make several predictions and recommendations, which we anticipate will help direct future experimental studies and structure-based drug discovery efforts against this vital enzyme.

  7. Genetic character of drug resistance in Trpanosoma brucei%锥虫抗药性的遗传特性

    Institute of Scientific and Technical Information of China (English)

    廖党金; 沈杰


    @@ 锥虫病是由锥虫寄生于人和动物的血液而引起人和动物的一种疾病.锥虫抗药性的产生,可能给人和家畜带来较严重的后果[1],国外于1908年已注意到锥虫的抗药性问题[2、3],而我国于1988年第一次口头报道在云南用厂方推荐的安锥赛治疗剂量难以治愈家畜锥虫病,1991年沈杰等正式报道了我国伊氏锥虫云南株和安徽株对安锥赛已产生抗药性[4].迄今,报告产生抗药性的锥虫虫种有布氏锥虫(Trypanosoma brucei)等常见的8个种,其它未报告的锥虫并不意味着不产生抗药性.已报告产生抗药性的药物有苏拉明(Suramine)等30多种抗锥虫药物.抗药性是能遗传的,对锥虫抗药性的遗传特性的了解,能帮助我们正确地选择和使用药物、减少和避免抗药性的产生及怎样消除已有的抗药性具有极其重要的作用,其次也有助于锥虫的生理、生化及生物学研究.

  8. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

    Energy Technology Data Exchange (ETDEWEB)

    Lepesheva, Galina I.; Park, Hee-Won; Hargrove, Tatiana Y.; Vanhollebeke, Benoit; Wawrzak, Zdzislaw; Harp, Joel M.; Sundaramoorthy, Munirathinam; Nes, W. David; Pays, Etienne; Chaudhuri, Minu; Villalta, Fernando; Waterman, Michael R. (ULdB); (Vanderbilt); (TTU); (Toronto); (NWU); (Meharry)


    Sterol 14{alpha}-demethylase (14DM, the CYP51 family of cytochrome P450) is an essential enzyme in sterol biosynthesis in eukaryotes. It serves as a major drug target for fungal diseases and can potentially become a target for treatment of human infections with protozoa. Here we present 1.9 {angstrom} resolution crystal structures of 14DM from the protozoan pathogen Trypanosoma brucei, ligand-free and complexed with a strong chemically selected inhibitor N-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl-4-(5-phenyl-1,3,4-oxadi-azol-2-yl)benzamide that we previously found to produce potent antiparasitic effects in Trypanosomatidae. This is the first structure of a eukaryotic microsomal 14DM that acts on sterol biosynthesis, and it differs profoundly from that of the water-soluble CYP51 family member from Mycobacterium tuberculosis, both in organization of the active site cavity and in the substrate access channel location. Inhibitor binding does not cause large scale conformational rearrangements, yet induces unanticipated local alterations in the active site, including formation of a hydrogen bond network that connects, via the inhibitor amide group fragment, two remote functionally essential protein segments and alters the heme environment. The inhibitor binding mode provides a possible explanation for both its functionally irreversible effect on the enzyme activity and its selectivity toward the 14DM from human pathogens versus the human 14DM ortholog. The structures shed new light on 14DM functional conservation and open an excellent opportunity for directed design of novel antiparasitic drugs.

  9. Case-control study of possible causative factors in mycosis fungoides

    Energy Technology Data Exchange (ETDEWEB)

    Tuyp, E.; Burgoyne, A.; Aitchison, T.; MacKie, R.


    A detailed case control study was carried out on 53 patients (33 males and 20 females) with histologically proven mycosis fungoides and on an age- and sex-matched control population. Possible causative factors investigated included occupation, recreation, and exposure to petrochemicals, pesticides, insecticides, and potential carcinogens. Exposure to plants of the Compositae family, tanning history, and chronic sun exposure were also investigated, as were smoking history, drug ingestion history, and other skin disease. Personal and family histories of other malignancies were also investigated. The only statistically significant difference to emerge was that the patients with mycosis fungoides had significantly more family history of atopic dermatitis. In view of the absence of any significant difference between patients and controls with regard to personal history of atopic dermatitis, this difference may be the result of multiple statistical testing rather than a phenomenon of true biological significance.

  10. Correlation not causation: the relationship between personality traits and political ideologies. (United States)

    Verhulst, Brad; Eaves, Lindon J; Hatemi, Peter K


    The assumption in the personality and politics literature is that a person's personality motivates them to develop certain political attitudes later in life. This assumption is founded on the simple correlation between the two constructs and the observation that personality traits are genetically influenced and develop in infancy, whereas political preferences develop later in life. Work in psychology, behavioral genetics, and recently political science, however, has demonstrated that political preferences also develop in childhood and are equally influenced by genetic factors. These findings cast doubt on the assumed causal relationship between personality and politics. Here we test the causal relationship between personality traits and political attitudes using a direction of causation structural model on a genetically informative sample. The results suggest that personality traits do not cause people to develop political attitudes; rather, the correlation between the two is a function of an innate common underlying genetic factor.

  11. [Etiological structure and resistance to antibacterial drugs of causative agents of cross infection in Donetsk]. (United States)

    Varenko, Iu S; Klochkov, A E; Revenko, T A; Tkachenko, S V; Fedorchenko, A M; Elagina, A B; Lebedeva, N Iu


    Tests for hemocultures were performed in 51 patients with clinical diagnoses of sepsis treated in a reanimation unit. Microbial cultures were isolated from 30 patients (58.9 per cent). Staphylococci in pure cultures and associations were the causative agents of sepsis in 26 patients (86.4 per cent). The cultures of E. coli, Y. enterocolitica and Streptococcus faecalis were isolated from 2, 1 and 1 patients, respectively. Pus specimens from 111 patients with postinjection suppuration were tested and staphylococci in pure cultures and associations were detected in 90 patients (81.8 per cent). The cultures of P. vulgaris, Streptococcus pyogenes, E. coli, Str. faecalis, Enterobacter spp. and Pseudomonas aeruginosa were isolated from 10, 5, 3, 1, 1 and 1 patients, respectively. The results showed that Staphylococci played the leading role in development of the hospital infections. Treatment of such patients should be performed with an account of antibioticograms since many strains are resistant to various antibiotics.

  12. Altered brain-gut axis in autism: comorbidity or causative mechanisms? (United States)

    Mayer, Emeran A; Padua, David; Tillisch, Kirsten


    The concept that alterated communications between the gut microbiome and the brain may play an important role in human brain disorders has recently received considerable attention. This is the result of provocative preclinical and some clinical evidence supporting early hypotheses about such communication in health and disease. Gastrointestinal symptoms are a common comorbidity in patients with autism spectrum disorders (ASD), even though the underlying mechanisms are largely unknown. In addition, alteration in the composition and metabolic products of the gut microbiome has long been implicated as a possible causative mechanism contributing to ASD pathophysiology, and this hypothesis has been supported by several recently published evidence from rodent models of autism induced by prenatal insults to the mother. Recent evidence in one such model involving maternal infection, that is characterized by alterations in behavior, gut physiology, microbial composition, and related metabolite profile, suggests a possible benefit of probiotic treatment on several of the observed abnormal behaviors.

  13. Identifying Coupling Structure in Complex Systems through the Optimal Causation Entropy Principle

    CERN Document Server

    Sun, Jie; Bollt, Erik M


    Inferring the coupling structure of complex systems from time series data in general by means of statistical and information-theoretic techniques is a challenging problem in applied science. The reliability of statistical inferences requires the construction of suitable information-theoretic measures that take into account both direct and indirect influences, manifest in the form of information flows, between the components within the system. In this work, we present an application of the optimal causation entropy (oCSE) principle to identify the coupling structure of a synthetic biological system, the repressilator. Specifically, when the system reaches an equilibrium state, we use a stochastic perturbation approach to extract time series data that approximate a linear stochastic process. Then, we present and jointly apply the aggregative discovery and progressive removal algorithms based on the oCSE principle to infer the coupling structure of the system from the measured data. Finally, we show that the suc...

  14. Evidence, illness, and causation: an epidemiological perspective on the Russo-Williamson Thesis. (United States)

    Fiorentino, Alexander R; Dammann, Olaf


    According to the Russo-Williamson Thesis, causal claims in the health sciences need to be supported by both difference-making and mechanistic evidence. In this article, we attempt to determine whether Evidence-based Medicine (EBM) can be improved through the consideration of mechanistic evidence. We discuss the practical composition and function of each RWT evidence type and propose that exposure-outcome evidence (previously known as difference-making evidence) provides associations that can be explained through a hypothesis of causation, while mechanistic evidence provides finer-grained associations and knowledge of entities that ultimately explains a causal hypothesis. We suggest that mechanistic evidence holds untapped potential to add value to the assessment of evidence quality in EBM and propose initial recommendations for the integration of mechanistic and exposure-outcome evidence to improve EBM by robustly leveraging available evidence in support of good medical decisions.

  15. Acute septic arthritis of the acromioclavicular joint caused by Haemophilus parainfluenzae: a rare causative origin. (United States)

    Hong, Myong-Joo; Kim, Yeon-Dong; Ham, Hyang-Do


    Septic arthritis of the acromioclavicular (AC) joint is a rare entity with symptoms that include erythema, swelling, and tenderness over the AC joint, fever, and limitation of shoulder motion with pain. In previous reports, Staphylococcus and Streptococcus species have been mentioned as common causative organisms. Haemophilus parainfluenzae is a normal inhabitant of the oral cavity, respiratory tract, gastrointestinal tract, and urogenital tract. However, it sometimes causes opportunistic infections leading to septic arthritis and osteomyelitis. AC joint infection associated with H.parainfluenzae is very rare, and only one case has been reported in the literature. Moreover, septic arthritis in immunocompetent patients is also very rare. Here, we report the case of a healthy patient with H. parainfluenzae-related septic arthritis of the AC joint.

  16. A Novel Basal Body Protein That Is a Polo-like Kinase Substrate Is Required for Basal Body Segregation and Flagellum Adhesion in Trypanosoma brucei. (United States)

    Hu, Huiqing; Zhou, Qing; Li, Ziyin


    The Polo-like kinase (PLK) in Trypanosoma brucei plays multiple roles in basal body segregation, flagellum attachment, and cytokinesis. However, the mechanistic role of TbPLK remains elusive, mainly because most of its substrates are not known. Here, we report a new substrate of TbPLK, SPBB1, and its essential roles in T. brucei. SPBB1 was identified through yeast two-hybrid screening with the kinase-dead TbPLK as the bait. It interacts with TbPLK in vitro and in vivo, and is phosphorylated by TbPLK in vitro. SPBB1 localizes to both the mature basal body and the probasal body throughout the cell cycle, and co-localizes with TbPLK at the basal body during early cell cycle stages. RNAi against SPBB1 in procyclic trypanosomes inhibited basal body segregation, disrupted the new flagellum attachment zone filament, detached the new flagellum, and caused defective cytokinesis. Moreover, RNAi of SPBB1 confined TbPLK at the basal body and the bilobe structure, resulting in constitutive phosphorylation of TbCentrin2 at the bilobe. Altogether, these results identified a basal body protein as a TbPLK substrate and its essential role in promoting basal body segregation and flagellum attachment zone filament assembly for flagellum adhesion and cytokinesis initiation.

  17. Nucleolar accumulation of RNA binding proteins induced by Actinomycin D is functional in Trypanosoma cruzi and Leishmania mexicana but not in T. brucei.

    Directory of Open Access Journals (Sweden)

    Ezequiel Názer

    Full Text Available We have recently shown in T. cruzi that a group of RNA Binding Proteins (RBPs, involved in mRNA metabolism, are accumulated into the nucleolus in response to Actinomycin D (ActD treatment. In this work, we have extended our analysis to other members of the trypanosomatid lineage. In agreement with our previous study, the mechanism seems to be conserved in L. mexicana, since both endogenous RBPs and a transgenic RBP were relocalized to the nucleolus in parasites exposed to ActD. In contrast, in T. brucei, neither endogenous RBPs (TbRRM1 and TbPABP2 nor a transgenic RBP from T. cruzi were accumulated into the nucleolus under such treatment. Interestingly, when a transgenic TbRRM1 was expressed in T. cruzi and the parasites exposed to ActD, TbRRM1 relocated to the nucleolus, suggesting that it contains the necessary sequence elements to be targeted to the nucleolus. Together, both experiments demonstrate that the mechanism behind nucleolar localization of RBPs, which is present in T. cruzi and L. mexicana, is not functional in T. brucei, suggesting that it has been lost or retained differentially during the evolution of the trypanosomatid lineage.

  18. Deletion of a novel protein kinase with PX and FYVE-related domains increases the rate of differentiation of Trypanosoma brucei. (United States)

    Vassella, E; Krämer, R; Turner, C M; Wankell, M; Modes, C; van den Bogaard, M; Boshart, M


    Growth control of African trypanosomes in the mammalian host is coupled to differentiation of a non-dividing life cycle stage, the stumpy bloodstream form. We show that a protein kinase with novel domain architecture is important for growth regulation. Zinc finger kinase (ZFK) has a kinase domain related to RAC and S6 kinases flanked by a FYVE-related zinc finger and a phox (PX) homology domain. To investigate the function of the kinase during cyclical development, a stable transformation procedure for bloodstream forms of differentiation-competent (pleomorphic) Trypanosoma brucei strains was established. Deletion of both allelic copies of ZFK by homologous recombination resulted in reduced growth of bloodstream-form parasites in culture, which was correlated with an increased rate of differentiation to the non-dividing stumpy form. Growth and differentiation rates were returned to wild-type level by ectopic ZFK expression. The phenotype is stage-specific, as growth of procyclic (insect form) trypanosomes was unaffected, and Deltazfk/Deltazfk clones were able to undergo full cyclical development in the tsetse fly vector. Deletion of ZFK in a differentiation-defective (monomorphic) strain of T. brucei did not change its growth rate in the bloodstream stage. This suggests a function of ZFK associated with the trypanosomes' decision between either cell cycle progression, as slender bloodstream form, or differentiation to the non-dividing stumpy form.

  19. Dynein Light Chain LC8 Is Required for RNA Polymerase I-Mediated Transcription in Trypanosoma brucei, Facilitating Assembly and Promoter Binding of Class I Transcription Factor A. (United States)

    Kirkham, Justin K; Park, Sung Hee; Nguyen, Tu N; Lee, Ju Huck; Günzl, Arthur


    Dynein light chain LC8 is highly conserved among eukaryotes and has both dynein-dependent and dynein-independent functions. Interestingly, LC8 was identified as a subunit of the class I transcription factor A (CITFA), which is essential for transcription by RNA polymerase I (Pol I) in the parasite Trypanosoma brucei. Given that LC8 has never been identified with a basal transcription factor and that T. brucei relies on RNA Pol I for expressing the variant surface glycoprotein (VSG), the key protein in antigenic variation, we investigated the CITFA-specific role of LC8. Depletion of LC8 from mammalian-infective bloodstream trypanosomes affected cell cycle progression, reduced the abundances of rRNA and VSG mRNA, and resulted in rapid cell death. Sedimentation analysis, coimmunoprecipitation of recombinant proteins, and bioinformatic analysis revealed an LC8 binding site near the N terminus of the subunit CITFA2. Mutation of this site prevented the formation of a CITFA2-LC8 heterotetramer and, in vivo, was lethal, affecting assembly of a functional CITFA complex. Gel shift assays and UV cross-linking experiments identified CITFA2 as a promoter-binding CITFA subunit. Accordingly, silencing of LC8 or CITFA2 resulted in a loss of CITFA from RNA Pol I promoters. Hence, we discovered an LC8 interaction that, unprecedentedly, has a basal function in transcription.

  20. Prevalence of musculoskeletal disorders and related occupational causative factors among electricity linemen: A narrative review

    Directory of Open Access Journals (Sweden)

    Vinothini Padmanathan


    Full Text Available Occupational tasks of linemen are highly associated with the development of work related musculoskeletal disorders (WRMDs. Although linemen are prone to develop WRMDs, there is paucity of information on the prevalence of WRMDs and related occupational causative factors. Therefore, the present review was conducted to report on the prevalence of WRMDs and to outline causative risk factors within occupational tasks in the lineman profession. Literature search was conducted in various databases such as Scopus, PubMed and ScienceDirect for articles published between 1996–2013. The articles were analyzed, selected and retrieved based on predetermined objectives, inclusion criteria and Medical Subject Headings (MeSH. In the review process only articles published in English were considered. The review identified moderate to high prevalence of WRMDs among the linemen population. Back and shoulder regions were highly affected compared to the other body regions. The review also reported occupational tasks such as bar installation, insulator fixation and manual handling of tools as high risk tasks that lead to the development of WRMDs. In addition, occupational tools such as ladders, manual cutters and manual presses were also identified as a potential ergonomic hazard. In conclusion, the current review identified that WRMDs are common in the back and shoulder regions among linemen. Also, a number of occupational risk factors were identified to be associated with WRMDs among the linemen. Hence, future research on prevention and intervention studies concerning lineman profession population in order to develop a good job practice are recommended. Int J Occup Med Environ Health 2016;29(5:725–734

  1. Ventilator-Associated Pneumonia and Causative Microorganisms in Intensive Care Unit: A Two Year Retrospective Analysis

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    Onur Palabıyık


    Full Text Available Objective: Ventilator-associated pneumonia (VAP is the most common nosocomial infection in the intensive care units (ICUs. It causes prolonged hospital stay and increases mortality. In this study, we aimed to investigate the rate of VAP, causative microorganisms, and their antibiotic susceptibilities in anaesthesiology and reanimation ICU (ARICU. Material and Method: This retrospective study included patients who were admitted to 12-bed ARICU between January 2013 and December 2014. The detection of VAP was done according to Centers for Disease Control and Prevention criteria. The rate of VAP, VAP ratio, and ventilator utilization ratio (VUR were calculated according to guidelines of Turkish National Infection Surveillance Control Group. Endotracheal aspiration samples were collected and cultivated. The identification of the isolates was performed by using VITEK-2 automated system. Antibiotic susceptibilities were determined by the disc diffusion method according to the Clinical and Laboratory Standards Institute criteria. Results: VAP was determined in 16 of 359 patients who required invasive mechanic ventilation for longer than 48 hours and hospitalized in ARICU. VUR was 65%, VAP ratio was 4.5% and the rate of VAP was 3.3 per 1000 ventilator days. Seventeen microorganisms were isolated from endotracheal aspiration samples, including Acinetobacter baumannii (n=6, Pseudomonas aeruginosa (n=4, methicillin-resistant Staphylococcus aureus (n=4, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens. The most sensitive antibiotics for microorganisms are listed as follows; Acinetobacter baumannii: colistin, Pseudomonas aeruginosa: amikacin, carbapenems; Methicillin-resistant Staphylococcus aureus: linezolid, teicoplanin, vancomycin, trimethoprim sulfamethoxazole; Klebsiella and Enterobacteriaceae species: carbapenems, trimethoprim sulfamethoxazole, gentamicin. Conclusion: Intermittent analyses and antibiotic susceptibilities of VAP

  2. Breastfeeding and the prevalence of allergic diseases in schoolchildren: Does reverse causation matter? (United States)

    Kusunoki, Takashi; Morimoto, Takeshi; Nishikomori, Ryuta; Yasumi, Takahiro; Heike, Toshio; Mukaida, Kumiko; Fujii, Tatsuya; Nakahata, Tatsutoshi


    Infants at higher risk of allergic diseases might be breastfed for longer periods compared with infants at lower risk in the hope that breastfeeding might reduce the risk of atopic disorders. Therefore, this intention could manifest as an apparent allergy-promoting effect of breastfeeding or reverse causation. To analyze the effect of breast feeding on the prevalence of allergic diseases at school age, a large questionnaire survey was administered to the parents of schoolchildren aged 7-15 yrs. 13,215 parents responded (response rate, 90.1%). Prevalence rates of allergic diseases were compared according to the type of feeding in infancy (either complete breastfeeding, mixed feeding or complete artificial feeding). In both univariate and multivariate analysis, compared with those with complete artificial feeding, those with mixed and complete breastfeeding showed a significantly lower prevalence of bronchial asthma (BA) (p = 0.01 and 0.003, respectively). On the other hand, in univariate analysis, the prevalence of atopic dermatitis (AD) and food allergy (FA) were significantly higher in those with complete breastfeeding (p = 0.04 and 0.01, respectively). There was a significantly higher proportion of complete breastfeeding among those with greater risk of allergic diseases (presence of family history, either eczema or wheeze within 6 months after birth, or FA in infancy). Therefore, our multivariate analysis included these risks as confounding factors, and we found that the promoting effects of breastfeeding on AD and FA disappeared. In conclusion, our data clearly showed the inhibitory effect of breastfeeding on the prevalence of BA at school age. The apparent promoting effect of breastfeeding on the prevalence of AD and FA is most likely because of reverse causation.

  3. A core MRB1 complex component is indispensable for RNA editing in insect and human infective stages of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Michelle L Ammerman

    Full Text Available Uridine insertion/deletion RNA editing is a unique and vital process in kinetoplastids, required for creation of translatable open reading frames in most mitochondrially-encoded RNAs. Emerging as a key player in this process is the mitochondrial RNA binding 1 (MRB1 complex. MRB1 comprises an RNA-independent core complex of at least six proteins, including the GAP1/2 guide RNA (gRNA binding proteins. The core interacts in an RNA-enhanced or -dependent manner with imprecisely defined TbRGG2 subcomplexes, Armadillo protein MRB10130, and additional factors that comprise the dynamic MRB1 complex. Towards understanding MRB1 complex function in RNA editing, we present here functional characterization of the pentein domain-containing MRB1 core protein, MRB11870. Inducible RNAi studies demonstrate that MRB11870 is essential for proliferation of both insect vector and human infective stage T. brucei. MRB11870 ablation causes a massive defect in RNA editing, affecting both pan-edited and minimally edited mRNAs, but does not substantially affect mitochondrial RNA stability or processing of precursor transcripts. The editing defect in MRB1-depleted cells occurs at the initiation stage of editing, as pre-edited mRNAs accumulate. However, the gRNAs that direct editing remain abundant in the knockdown cells. To examine the contribution of MRB11870 to MRB1 macromolecular interactions, we tagged core complexes and analyzed their composition and associated proteins in the presence and absence of MRB11870. These studies demonstrated that MRB11870 is essential for association of GAP1/2 with the core, as well as for interaction of the core with other proteins and subcomplexes. Together, these data support a model in which the MRB1 core mediates functional interaction of gRNAs with the editing machinery, having GAP1/2 as its gRNA binding constituents. MRB11870 is a critical component of the core, essential for its structure and function.

  4. Quantitative Mass Spectrometry-Based Analysis of β-D-Glucosyl-5-Hydroxymethyluracil in Genomic DNA of Trypanosoma brucei (United States)

    Liu, Shuo; Ji, Debin; Cliffe, Laura; Sabatini, Robert; Wang, Yinsheng


    β-D-glucosyl-5-hydroxymethyluracil (base J) is a hyper-modified nucleobase found in the nuclear DNA of kinetoplastid parasites. With replacement of a fraction of thymine in DNA, J is localized primarily in telomeric regions of all organisms carrying this modified base. The biosynthesis of J occurs in two putative steps: first, a specific thymine in DNA is recognized and converted into 5-hydroxymethyluracil (5-HmU) by J-binding proteins (JBP1 and JBP2); a glucosyl transferase (GT) subsequently glucosylates the 5-HmU to yield J. Although several recent studies revealed the roles of internal J in regulating transcription in kinetoplastids, functions of telomeric J and proteins involved in J synthesis remain elusive. Assessing the functions of base J and understanding fully its biosynthesis necessitate the measurement of its level in cells and organisms. In this study, we reported a reversed-phase HPLC coupled with tandem mass spectrometry (LC-MS/MS) method, together with the use of a surrogate internal standard (β-D-glucosyl-5-hydroxymethyl-2'-deoxycytidine, 5-gHmdC), for the accurate detection of β-D-glucosyl-5-hydroxymethyl-2'-deoxyuridine (dJ) in Trypanosoma brucei DNA. For comparison, we also measured the level of the precursor for dJ synthesis [i.e. 5-hydroxymethyl-2'-deoxyuridine (5-HmdU)]. We found that base J was not detectable in the JBP-null cells whereas it replaced approximately 0.5% thymine in wild-type cells, which was accompanied with a markedly decreased level of 5-HmdU in JBP1/JBP2-null strain relative to the wild-type strain. These results provided direct evidence supporting that JBP proteins play an important role in oxidizing thymidine to form 5-HmdU, which facilitated the generation of dJ. This is the first report about the application of LC-MS/MS for the quantification of base J. The analytical method built a solid foundation for dissecting the molecular mechanisms of J biosynthesis and assessing the biological functions of base J in the

  5. An ERP Study of Causative Cleft Construction in Japanese: Evidence for the Preference of Shorter Linear Distance in Sentence Comprehension (United States)

    Yano, Masataka; Sakamoto, Tsutomu


    This study examined the processing of two types of Japanese causative cleft constructions (subject-gap vs. object-gap) by conducting an event-related brain potential experiment to clarify the processing mechanism of long-distance dependencies. The results demonstrated that the subject-gap constructions elicited larger P600 effects than the…

  6. 20 CFR 718.204 - Total disability and disability causation defined; criteria for determining total disability and... (United States)


    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Total disability and disability causation defined; criteria for determining total disability and total disability due to pneumoconiosis. 718.204... MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED STANDARDS FOR DETERMINING COAL MINERS' TOTAL...

  7. The In Vitro Antifungal Activity of Sudanese Medicinal Plants against Madurella mycetomatis, the Eumycetoma Major Causative Agent

    NARCIS (Netherlands)

    H. Elfadil (Hassabelrasoul); A.H. Fahal (Ahmed); W. Kloezen (Wendy); E.M. Ahmed (Elhadi M.); W.W.J. van de Sande (Wendy)


    textabstractEumycetoma is a debilitating chronic inflammatory fungal infection that exists worldwide but it is endemic in many tropical and subtropical regions. The major causative organism is the fungus Madurella mycetomatis. The current treatment of eumycetoma is suboptimal and characterized by lo

  8. Can a Microwave Heat up Coffee? How English- and Japanese-Speaking Children Choose Subjects in Lexical Causative Sentences (United States)

    Kanero, Junko; Hirsh-Pasek, Kathy; Golinkoff, Roberta Michnick


    Languages differ greatly in how they express causal events. In languages like Japanese, the subjects of causative sentences, or "causers," are generally animate and intentional, whereas in other languages like English, causers range widely from animate beings to inanimate objects (e.g. Wolff, Jeon & Li, 2009). This paper explores…

  9. Evidence for a close phylogenetic relationship between Melissococcus pluton, the causative agent of European foulbrood disease, and the genus Enterococcus. (United States)

    Cai, J; Collins, M D


    The 16S rRNA gene sequence of Melissococcus pluton, the causative agent of European foulbrood disease, was determined in order to investigate the phylogenetic relationships between this organism and other low-G + C-content gram-positive bacteria. A comparative sequence analysis revealed that M. pluton is a close phylogenetic relative of the genus Enterococcus.

  10. Evidence of Lexical Transfer in Learner Syntax: The Acquisition of English Causatives by Speakers of Hindi-Urdu and Vietnamese. (United States)

    Helms-Park, Rena


    Reports the findings of a study in which transfer of verb properties was investigated via syntactic data elicited from second language learners. The performance of Hindi-Urdu speakers on tests of English causatives was compared with that of Vietnamese speakers, because there are five significant differences between causativization patterns in…

  11. Lipid-drug conjugate nanoparticles of the hydrophilic drug diminazene-cytotoxicity testing and mouse serum adsorption

    NARCIS (Netherlands)

    Olbrich, C.; Gessner, A.; Schroder, W.; Kayser, Oliver; Muller, R.H.


    Sleeping sickness is a widely distributed disease in great parts of Africa. It is caused by Trypanosoma brucei gambiense and rhodiense, transmitted by the Tse-Tse fly. After a hemolymphatic stage, the parasites enter the central nervous system where they cannot be reached by hydrophilic drugs. To po

  12. Irregular location of major pectoral muscle can be a causative factor of pectus excavatum. (United States)

    Nagasao, Tomohisa; Shimizu, Yusuke; Morotomi, Tadaaki; Takano, Naoki; Jiang, Hua; Kishi, Kazuo


    Pectus excavatum-commonly known as funnel chest-is one of the most frequently observed congenital deformities, in which the patients' thoraces present concavity. This paper presents our original hypothesis that the abnormal positioning of the major pectoral muscle can be a potential factor in the occurrence of pectus excavatum, and evaluates the validity of the hypothesis by performing an anatomical and a biomechanical study. An anatomical study on clinical cases revealed that the major pectoral muscle tends to be positioned more superiorly in pectus excavatum patients than in normal persons. The biomechanical study, using three-dimensional finite element dynamic simulation, revealed that the major pectoral muscle functions to elevate the sternum and that the elevating effect is reduced when the muscle is located at superior regions on the thoracic wall. These findings support our hypothesis that the abnormal position of the major pectoral muscle is a potential causative factor for pectus excavatum. This hypothesis suggests that, during surgical correction of pectus excavatum with an open approach, surgeons should reposition the major pectoral muscle to its correct anatomical position to avoid recurrence.

  13. Alzheimer’s Disease Causation by Copper Toxicity and Treatment with Zinc

    Directory of Open Access Journals (Sweden)

    George J Brewer


    Full Text Available Evidence will be presented that the Alzheimer’s disease (AD epidemic is new, the disease being very rare in the 1900s. The incidence is increasing rapidly, but only in developed countries. We postulate that the new emerging environmental factor partially causal of the AD epidemic is ingestion of inorganic copper from drinking water and taking supplement pills, along with a high fat diet. Inorganic copper can be partially directly absorbed and elevate the serum free copper pool. The Squitti group has shown that serum free copper is elevated in AD, correlates with cognition, and predicts cognition loss. Thus, our inorganic copper hypothesis fits well with the Squitti group data. We have also shown that AD patients are zinc deficient compared to age-matched controls. Because zinc is a neuronal protective factor, we postulate that zinc deficiency may also be partially causative of AD. We carried out a small 6 month double blind study of a new zinc formulation and found that in patients age 70 and over, it protected against cognition loss. Zinc therapy also significantly reduced serum free copper in AD patients, so efficacy may come from restoring normal zinc levels, or from lowering serum free copper, or from both.

  14. Acanthamoeba genotypes T3 and T4 as causative agents of amoebic keratitis in Mexico. (United States)

    Omaña-Molina, Maritza; Vanzzini-Zago, Virginia; Hernandez-Martinez, Dolores; Gonzalez-Robles, Arturo; Salazar-Villatoro, Lizbeth; Ramirez-Flores, Elizabeth; Oregon-Miranda, Eric; Lorenzo-Morales, Jacob; Martinez-Palomo, Adolfo


    Free-living amoebae (FLA) are widely distributed worldwide. Some genera included in this group act as opportunistic pathogens causing fatal encephalitis and Acanthamoeba keratitis (AK), a sight-threatening infection of the cornea associated with the use of soft contact lenses that could even end in blindness if an early diagnosis and treatment are not achieved. Furthermore, the numbers of AK cases keep rising worldwide mainly due to an increase of contact lens wearers and lack of hygiene in the maintenance of lenses and their cases. In Mexico, no cases of AK have been described so far although the isolation of other pathogenic FLA such as Naegleria fowleri and Balamuthia mandrillaris from both clinical and environmental sources has been reported. The present study reports two cases of Acanthamoeba keratitis diagnosed in two patients admitted to the Hospital "Luis Sánchez Bulnes" for Blindness Prevention in Mexico City, Mexico. Corneal scrapes and contact lenses were checked for the presence of Acanthamoeba strains in both patients. Strains were axenized after initial isolation to classify at the genotype level. After sequencing the diagnostic fragment 3 (DF3) region located on the 18S ribosomal DNA (rDNA) gene of Acanthamoeba, genotype T3 and genotype T4 were identified in clinical case 1 and 2, respectively. To our knowledge, these are the first reported cases of AK in Mexico in the literature and the first description of Acanthamoeba genotypes T3 and T4 as causative agents of amoebic infection.

  15. Identification of causative compounds and microorganisms for musty odor occurrence in the Huangpu River, China

    Institute of Scientific and Technical Information of China (English)

    Daolin Sun; Jianwei Yu; Wei An; Min Yang; Guoguang Chen; Shujun Zhang


    There are regular problems of musty odor in the Huangpu River,a major source of drinking water for Shanghai,China.In this study,the musty odor and its main causative compounds in the Huangpu River source water were confirmed through a yearly investigation using flavor profile analysis combined with HSPME-GC-MS analysis.The investigation showed that 2-methylisoborneol (2-MIB) with a concentration level between 28.6 and 71.0 ng/L was responsible for the musty odor in summer from July to September.Microscopic observation confirmed with the cloning results showed that Phormidium spp.,which accounted for 80%-95% of the algal cell density,was the microorganisms responsible for the production of 2-MIB and the estimated 2-MIB yield was 0.022 pg/cell.Results from a wide-area sampling campaign in the Huangpu River watershed showed that,other than the large tributaries receiving water from Tai Lake,several small creeks close to the intake may have contributed most of the 2-MIB and the Phormidium the Huangpu River source water.This study provides methodology for the investigation of odor causing compounds and microorganisms in river-type source water,and the result will be useful for water quality control in both source water and drinking water.

  16. [Diagnosis of syringomyelia and its classification on the basis of symptoms, radiological appearance, and causative disorders]. (United States)

    Terae, Satoshi; Hida, Kazutoshi; Sasaki, Hidenao


    Although it is easier to accurately diagnose syringomyelia with the advent of magnetic resonance (MR) imaging, syringomyelia still poses challenges to clinicians because of its complex symptomatology, uncertain pathogenesis and multiple treatment options. Here, we propose criteria for classification of syringomyelia not related to those associated with spinal intramedullary tumors. The classification aims to distinguish between the presyrinx state and syringomyelia, between asymptomatic and symptomatic syringomyelia and to clarify the associated disorders such as Chiari malformations, spinal arachnoiditis and spinal cord trauma. Diagnostic criteria for Chiari I and II malformations with MR imaging were also defined. Several hypotheses proposed to explain the pathogenesis of syringomyelia associated with Chiari I malformation were reviewed. A questionnaire survey on syringomyelia based on the proposed criteria conducted between November 2009 and April 2010 in Japan revealed that 160 (22.6%) of the 708 patients were asymptomatic. Chiari I malformation was the most frequent causative disorder (48.3%), followed by spinal arachnoiditis (15.8%). The proposed criteria for classification of syringomyelia will facilitate a nationwide survey of syringomyelia in Japan. Such a survey will inform us of its prevalence and prognosis more precisely, and enable us to build a reliable database that may help determine the optimal treatment for the disease in the future.

  17. Metal-dependent gene regulation in the causative agent of Lyme disease

    Directory of Open Access Journals (Sweden)

    Bryan eTroxell


    Full Text Available Borrelia burgdorferi (Bb is the causative agent of Lyme disease transmitted to humans by ticks of the Ixodes spp. Bb is a unique bacterial pathogen because it does not require iron (Fe2+ for its metabolism. Bb encodes a ferritin-like Dps homolog called NapA (also called BicA, which can bind Fe or copper (Cu2+, and a manganese (Mn2+ transport protein, BmtA; both proteins are required for colonization of the tick vector, but BmtA is also required for the murine host. This demonstrates that Bb’s metal homeostasis is a critical facet of the complex enzootic life cycle between the arthropod and murine hosts. Although metals are known to influence the expression of virulence determinants during infection, it is unknown how or if metals regulate virulence in Bb. Recent evidence demonstrates that Bb modulates the intracellular Mn2+ and zinc (Zn2+ content and, in turn, these metals regulate gene expression through influencing the Ferric Uptake Regulator (Fur homolog Borrelia Oxidative Stress Regulator (BosR. This mini-review focuses on the burgeoning study of metal-dependent gene regulation within Bb.

  18. CRISPR Repair Reveals Causative Mutation in a Preclinical Model of Retinitis Pigmentosa. (United States)

    Wu, Wen-Hsuan; Tsai, Yi-Ting; Justus, Sally; Lee, Ting-Ting; Zhang, Lijuan; Lin, Chyuan-Sheng; Bassuk, Alexander G; Mahajan, Vinit B; Tsang, Stephen H


    Massive parallel sequencing enables identification of numerous genetic variants in mutant organisms, but determining pathogenicity of any one mutation can be daunting. The most commonly studied preclinical model of retinitis pigmentosa called the "rodless" (rd1) mouse is homozygous for two mutations: a nonsense point mutation (Y347X) and an intronic insertion of a leukemia virus (Xmv-28). Distinguishing which mutation causes retinal degeneration is still under debate nearly a century after the discovery of this model organism. Here, we performed gene editing using the CRISPR/Cas9 system and demonstrated that the Y347X mutation is the causative variant of disease. Genome editing in the first generation produced animals that were mosaic for the corrected allele but still showed neurofunction preservation despite low repair frequencies. Furthermore, second-generation CRISPR-repaired mice showed an even more robust rescue and amelioration of the disease. This predicts excellent outcomes for gene editing in diseased human tissue, as Pde6b, the mutated gene in rd1 mice, has an orthologous intron-exon relationship comparable with the human PDE6B gene. Not only do these findings resolve the debate surrounding the source of neurodegeneration in the rd1 model, but they also provide the first example of homology-directed recombination-mediated gene correction in the visual system.

  19. Clinical features of Bloom syndrome and function of the causative gene, BLM helicase. (United States)

    Kaneko, Hideo; Kondo, Naomi


    Bloom syndrome is a rare autosomal recessive genetic disorder characterized by growth deficiency, unusual facies, sun-sensitive telangiectatic erythema, immunodeficiency and predisposition to cancer. The causative gene for Bloom syndrome is BLM, which encodes the BLM RecQ helicase homolog protein. The first part of this review describes a long-term follow-up study of two Bloom syndrome siblings. Subsequently, the focus is placed on the functional domains of BLM. Laboratory diagnosis of Bloom syndrome by detecting mutations in BLM is laborious and impractical, unless there are common mutations in a population. Immunoblot and immunohistochemical analyses for the detection of the BLM protein using a polyclonal BLM antibody, which are useful approaches for clinical diagnosis of Bloom syndrome, are also described. In addition, a useful adjunct for the diagnosis of Bloom syndrome in terms of the BLM function is investigated, since disease cells must have the defective BLM helicase function. This review also discusses the nuclear localization signal of BLM, the proteins that interact with BLM and tumors originating from Bloom syndrome.

  20. Metal-dependent gene regulation in the causative agent of Lyme disease. (United States)

    Troxell, Bryan; Yang, X Frank


    Borrelia burgdorferi (Bb) is the causative agent of Lyme disease transmitted to humans by ticks of the Ixodes spp. Bb is a unique bacterial pathogen because it does not require iron (Fe(2+)) for its metabolism. Bb encodes a ferritin-like Dps homolog called NapA (also called BicA), which can bind Fe or copper (Cu(2+)), and a manganese (Mn(2+)) transport protein, Borrelia metal transporter A (BmtA); both proteins are required for colonization of the tick vector, but BmtA is also required for the murine host. This demonstrates that Bb's metal homeostasis is a critical facet of the complex enzootic life cycle between the arthropod and murine hosts. Although metals are known to influence the expression of virulence determinants during infection, it is unknown how or if metals regulate virulence in Bb. Recent evidence demonstrates that Bb modulates the intracellular Mn(2+) and zinc (Zn(2+)) content and, in turn, these metals regulate gene expression through influencing the Ferric Uptake Regulator (Fur) homolog Borrelia Oxidative Stress Regulator (BosR). This mini-review focuses on the burgeoning study of metal-dependent gene regulation within Bb.

  1. Ureaplasma urealyticum as a causative organism of urinary tract infection stones. (United States)

    Mobarak, A; Tharwat, A


    Ureaplasma urealyticum is a fastidious organism which is not recovered by conventional bacterial cultures techniques, but special cultures are required for its isolation and identification. As it is a urease-producing organism, it is considered a risk factor for the formation of struvite calculi in the urinary tract. A total of 30 patients with urinary infection stones (19 of them with the 1st formation and 11 with recurrent stone formation) were included in the study. Both bladder urine specimen (cystoscopically obtained) and stones removed were subjected to conventional cultures and also to Ureaplasma specific cultures (A7 agar and U9 broth). The results of culture techniques revealed that 86.7% of patients had aerobic organisms (E. coli in 46.7%, Klebsiella in 30%, Proteus in 6.7% and Pseudomonas in 3.3%) and 26.7% showed U. urealyticum in mid stream urine. As regards stone cultures, they revealed aerobic organisms in 76.7%, and U. urealyticum in 20%. Sensitivity tests for U. urealyticum showed that minocycline was the most effective antimicrobial followed by tetracycline and ciprofloxacin. From these data, we conclude that U. urealyticum may be the causative organism for infection stone and should be searched for via its specific cultures, especially in patients with recurrent stones and with the so-called sterile pyuria.

  2. 3-(3-amino-3-carboxypropyl)-5,6-Dihydrouridine is one of two novel post-transcriptional modifications in tRNALys(UUU) from Trypanosoma brucei

    DEFF Research Database (Denmark)

    Krog, Jesper Schak; Español, Yaiza; Giessing, Anders M B;


    was MALDI-TOF MS of two independent digests of the tRNA, with RNase A and RNase T1, respectively. This revealed digestion products harbouring mass-changing modifications. Next, the modifications were mapped at the nucleotide level in the RNase products by tandem MS. Comparison with the sequence......tRNA is the most heavily modified of all RNA types, with typically 10-20% of the residues being post-transcriptionally altered. Unravelling the modification pattern of a tRNA is a challenging task; there are 92 currently known tRNA modifications [1], many of which are chemically similar....... Furthermore, the tRNA has to be investigated with single-nucleotide resolution in order to ensure complete mapping of all modifications. In the present work, we characterized tRNA(Lys) (UUU) from Trypanosoma brucei, and provide a complete overview of its post-transcriptional modifications. The first step...

  3. Eleganolone, a Diterpene from the French Marine Alga Bifurcaria bifurcata Inhibits Growth of the Human Pathogens Trypanosoma brucei and Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Anne-Marie Rusig


    Full Text Available Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI = 11.6. Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0. However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6.

  4. Eleganolone, a Diterpene from the French Marine Alga Bifurcaria bifurcata Inhibits Growth of the Human Pathogens Trypanosoma brucei and Plasmodium falciparum (United States)

    Gallé, Jean-Baptiste; Attioua, Barthélémy; Kaiser, Marcel; Rusig, Anne-Marie; Lobstein, Annelise; Vonthron-Sénécheau, Catherine


    Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI) = 11.6). Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0). However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6). PMID:23442789


    Institute of Scientific and Technical Information of China (English)

    原丽红; 林本夫; 王祥生; 李莲瑞


    布氏锥虫(Trypanosoma brucei)是一种原虫性寄生虫,通过采采蝇(tsets fly)的传播感染人和其它哺乳动物,导致人的昏睡病和家畜的那卡那病。布氏锥虫有两个截然不同的生活阶段,即血液期(bloodstream stage,寄生于哺乳动物血细胞内)和昆虫期(insect stage,又叫循环期或感染期,寄生于采采蝇的中肠内)。

  6. The response of trypanosomes and other eukaryotes to ER stress and the spliced leader RNA silencing (SLS) pathway in Trypanosoma brucei. (United States)

    Michaeli, Shulamit


    The unfolded protein response (UPR) is induced when the quality control machinery of the cell is overloaded with unfolded proteins or when one of the functions of the endoplasmic reticulum (ER) is perturbed. Here, I describe UPR in yeast and mammals, and compare it to what we know about pathogenic fungi and the parasitic protozoans from the order kinetoplastida, focusing on the novel pathway the spliced leader silencing (SLS) in Trypanosoma brucei. Trypanosomes lack conventional transcription regulation, and thus, lack most of the UPR machinery present in other eukaryotes. Trypanosome genes are transcribed in polycistronic units that are processed by trans-splicing and polyadenylation. In trans-splicing, which is essential for processing of each mRNA, an exon known as the spliced leader (SL) is added to all mRNAs from a small RNA, the SL RNA. Under severe ER stress, T. brucei elicits the SLS pathway. In SLS, the transcription of the SL RNA gene is extinguished, and the entire transcription complex dissociates from the SL RNA promoter. Induction of SLS is mediated by an ER-associated kinase (PK3) that migrates to the nucleus, where it phosphorylates the TATA-binding protein (TRF4), leading shut-off of SL RNA transcription. As a result, trans-splicing is inhibited and the parasites activate a programmed cell death (PCD) pathway. Despite the ability to sense the ER stress, the different eukaryotes, especially unicellular parasites and pathogenic fungi, developed a variety of unique and different ways to sense and adjust to this stress in a manner different from their host.

  7. Characterization of a Novel Class I Transcription Factor A (CITFA) Subunit That Is Indispensable for Transcription by the Multifunctional RNA Polymerase I of Trypanosoma brucei

    KAUST Repository

    Nguyen, T. N.


    Trypanosoma brucei is the only organism known to have evolved a multifunctional RNA polymerase I (pol I) system that is used to express the parasite\\'s ribosomal RNAs, as well as its major cell surface antigens, namely, the variant surface glycoprotein (VSG) and procyclin, which are vital for establishing successful infections in the mammalian host and the tsetse vector, respectively. Thus far, biochemical analyses of the T. brucei RNA pol I transcription machinery have elucidated the subunit structure of the enzyme and identified the class I transcription factor A (CITFA). CITFA binds to RNA pol I promoters, and its CITFA-2 subunit was shown to be absolutely essential for RNA pol I transcription in the parasite. Tandem affinity purification (TAP) of CITFA revealed the subunits CITFA-1 to -6, which are conserved only among kinetoplastid organisms, plus the dynein light chain DYNLL1. Here, by tagging CITFA-6 instead of CITFA-2, a complex was purified that contained all known CITFA subunits, as well as a novel proline-rich protein. Functional studies carried out in vivo and in vitro, as well as a colocalization study, unequivocally demonstrated that this protein is a bona fide CITFA subunit, essential for parasite viability and indispensable for RNA pol I transcription of ribosomal gene units and the active VSG expression site in the mammalian-infective life cycle stage of the parasite. Interestingly, CITFA-7 function appears to be species specific, because expression of an RNA interference (RNAi)-resistant CITFA-7 transgene from Trypanosoma cruzi could not rescue the lethal phenotype of silencing endogenous CITFA-7.

  8. The role of B-cells and IgM antibodies in parasitemia, anemia, and VSG switching in Trypanosoma brucei-infected mice.

    Directory of Open Access Journals (Sweden)

    Stefan Magez

    Full Text Available African trypanosomes are extracellular parasitic protozoa, predominantly transmitted by the bite of the haematophagic tsetse fly. The main mechanism considered to mediate parasitemia control in a mammalian host is the continuous interaction between antibodies and the parasite surface, covered by variant-specific surface glycoproteins. Early experimental studies have shown that B-cell responses can be strongly protective but are limited by their VSG-specificity. We have used B-cell (microMT and IgM-deficient (IgM(-/- mice to investigate the role of B-cells and IgM antibodies in parasitemia control and the in vivo induction of trypanosomiasis-associated anemia. These infection studies revealed that that the initial setting of peak levels of parasitemia in Trypanosoma brucei-infected microMT and IgM(-/- mice occurred independent of the presence of B-cells. However, B-cells helped to periodically reduce circulating parasites levels and were required for long term survival, while IgM antibodies played only a limited role in this process. Infection-associated anemia, hypothesized to be mediated by B-cell responses, was induced during infection in microMT mice as well as in IgM(-/- mice, and as such occurred independently from the infection-induced host antibody response. Antigenic variation, the main immune evasion mechanism of African trypanosomes, occurred independently from host antibody responses against the parasite's ever-changing antigenic glycoprotein coat. Collectively, these results demonstrated that in murine experimental T. brucei trypanosomiasis, B-cells were crucial for periodic peak parasitemia clearance, whereas parasite-induced IgM antibodies played only a limited role in the outcome of the infection.

  9. Structures of Trypanosoma brucei methionyl-tRNA synthetase with urea-based inhibitors provide guidance for drug design against sleeping sickness.

    Directory of Open Access Journals (Sweden)

    Cho Yeow Koh


    Full Text Available Methionyl-tRNA synthetase of Trypanosoma brucei (TbMetRS is an important target in the development of new antitrypanosomal drugs. The enzyme is essential, highly flexible and displaying a large degree of changes in protein domains and binding pockets in the presence of substrate, product and inhibitors. Targeting this protein will benefit from a profound understanding of how its structure adapts to ligand binding. A series of urea-based inhibitors (UBIs has been developed with IC50 values as low as 19 nM against the enzyme. The UBIs were shown to be orally available and permeable through the blood-brain barrier, and are therefore candidates for development of drugs for the treatment of late stage human African trypanosomiasis. Here, we expand the structural diversity of inhibitors from the previously reported collection and tested for their inhibitory effect on TbMetRS and on the growth of T. brucei cells. The binding modes and binding pockets of 14 UBIs are revealed by determination of their crystal structures in complex with TbMetRS at resolutions between 2.2 Å to 2.9 Å. The structures show binding of the UBIs through conformational selection, including occupancy of the enlarged methionine pocket and the auxiliary pocket. General principles underlying the affinity of UBIs for TbMetRS are derived from these structures, in particular the optimum way to fill the two binding pockets. The conserved auxiliary pocket might play a role in binding tRNA. In addition, a crystal structure of a ternary TbMetRS•inhibitor•AMPPCP complex indicates that the UBIs are not competing with ATP for binding, instead are interacting with ATP through hydrogen bond. This suggests a possibility that a general 'ATP-engaging' binding mode can be utilized for the design and development of inhibitors targeting tRNA synthetases of other disease-causing pathogen.

  10. Cytosolic NADPH homeostasis in glucose-starved procyclic Trypanosoma brucei relies on malic enzyme and the pentose phosphate pathway fed by gluconeogenic flux. (United States)

    Allmann, Stefan; Morand, Pauline; Ebikeme, Charles; Gales, Lara; Biran, Marc; Hubert, Jane; Brennand, Ana; Mazet, Muriel; Franconi, Jean-Michel; Michels, Paul A M; Portais, Jean-Charles; Boshart, Michael; Bringaud, Frédéric


    All living organisms depend on NADPH production to feed essential biosyntheses and for oxidative stress defense. Protozoan parasites such as the sleeping sickness pathogen Trypanosoma brucei adapt to different host environments, carbon sources, and oxidative stresses during their infectious life cycle. The procyclic stage develops in the midgut of the tsetse insect vector, where they rely on proline as carbon source, although they prefer glucose when grown in rich media. Here, we investigate the flexible and carbon source-dependent use of NADPH synthesis pathways in the cytosol of the procyclic stage. The T. brucei genome encodes two cytosolic NADPH-producing pathways, the pentose phosphate pathway (PPP) and the NADP-dependent malic enzyme (MEc). Reverse genetic blocking of those pathways and a specific inhibitor (dehydroepiandrosterone) of glucose-6-phosphate dehydrogenase together established redundancy with respect to H2O2 stress management and parasite growth. Blocking both pathways resulted in ∼10-fold increase of susceptibility to H2O2 stress and cell death. Unexpectedly, the same pathway redundancy was observed in glucose-rich and glucose-depleted conditions, suggesting that gluconeogenesis can feed the PPP to provide NADPH. This was confirmed by (i) a lethal phenotype of RNAi-mediated depletion of glucose-6-phosphate isomerase (PGI) in the glucose-depleted Δmec/Δmec null background, (ii) an ∼10-fold increase of susceptibility to H2O2 stress observed for the Δmec/Δmec/(RNAi)PGI double mutant when compared with the single mutants, and (iii) the (13)C enrichment of glycolytic and PPP intermediates from cells incubated with [U-(13)C]proline, in the absence of glucose. Gluconeogenesis-supported NADPH supply may also be important for nucleotide and glycoconjugate syntheses in the insect host.

  11. A case history study on causation of the landslide in Santa Clara, California, USA

    Institute of Scientific and Technical Information of China (English)

    Yun Liao; Sadek M. Derrega; Craig A. Hall


    This paper presents a case history study on the geologic investigation and numerical modeling of a reactivated landslide in the County of Santa Clara, California to identify the failure mechanism. The landslide occurred on an approximately 18.3-m high, north-facing slope during March 2011. The land-slide measured about 33.5 m in width and about 51.8 m in length. Along the toe of the slope, a residential structure with a swimming pool was built on a cut and fill pad and there are several other structures present along the western side of the pad. The landslide occurred immediately to the south of the residential building and moved northward between the County Road A and the house’s side yard. The movement of the landslide resulted in damaging the west-bound traffic lane of County Road A and encroached onto the paved driveway for the residential property. An investigation was performed to identify the failure mechanism of the landslide to conclude whether Road A re-alignment by the County or prominent cutting performed along the lower portion of the slope by the homeowner during 2000 through 2004 contributed to the reactivation of the old landslide deposit. The investigation included site reconnaissance, reviewing available published geologic information, reviewing site-specific geologic and geotechnical data developed by other consultants, and performing numerical modeling. The outcomes of the investigation indicate that the primary causation for the reactivation and failure of the subject pre-existing landslide is the prominent cutting performed along the lower portion of the slope during 2000 through 2004 and water tank cut bench. The Road A re-alignment did not contribute to the reactivation of the old landslide deposit.

  12. Pathology of camel tuberculosis and molecular characterization of its causative agents in pastoral regions of Ethiopia.

    Directory of Open Access Journals (Sweden)

    Gezahegne Mamo

    Full Text Available A cross sectional study was conducted on 906 apparently healthy camels slaughtered at Akaki and Metehara abattoirs to investigate the pathology of camel tuberculosis (TB and characterize its causative agents using postmortem examination, mycobacteriological culturing, and multiplex polymerase chain reaction (PCR, region of difference-4 (RD4-based PCR and spoligotyping. The prevalence of camel TB was 10.04% (91/906 on the basis of pathology and it was significantly higher in females (χ(2 = 4.789; P = 0.029. The tropism of TB lesions was significantly different among the lymph nodes (χ(2 = 22.697; P = 0.002 and lung lobes (χ(2 = 17.901; P = 0.006. Mycobacterial growth was observed in 34% (31/91 of camels with grossly suspicious TB lesions. Upon further molecular characterization using multiplex PCR, 68% (21/31 of the colonies showed a positive signal for the genus Mycobacterium, of which two were confirmed Mycobacterium bovis (M. bovis by RD4 deletion typing. Further characterization of the two M. bovis at strains level revealed that one of the strains was SB0133 while the other strain was new and had not been reported to the M. bovis database prior to this study. Hence, it has now been reported to the database, and designated as SB1953. In conclusion, the results of the present study have shown that the majority of camel TB lesions are caused by mycobacteria other than Mycobacterium tuberculosis complex. And hence further identification and characterization of these species would be useful towards the efforts made to control TB in camels.

  13. The aqueous humor outflow pathways in glaucoma: A unifying concept of disease mechanisms and causative treatment. (United States)

    Braunger, Barbara M; Fuchshofer, Rudolf; Tamm, Ernst R


    Intraocular pressure (IOP) is the critical risk factor for glaucoma, a neurodegenerative disease and frequent cause of blindness worldwide. As of today, all effective strategies to treat glaucoma aim at lowering IOP. IOP is generated and maintained via the aqueous humor circulation system in the anterior eye. Aqueous humor is secreted by the ciliary processes and exits the eye through the trabecular meshwork (TM) or the uveoscleral outflow pathways. The TM outflow pathways provide resistance to aqueous humor outflow and IOP builds up in response to it. In the normal eye, the resistance is localized in the inner wall region, which comprises the juxtacanalicular connective tissue (JCT) and the inner wall endothelium of Schlemm's canal (SC). Outflow resistance in the inner wall region is lowered through the contraction of the ciliary muscle or the relaxation of contractile myofibroblasts in the posterior part of the TM and the adjacent scleral spur. Patients with primary open-angle glaucoma (POAG), the most frequent form of glaucoma, typically suffer from an abnormally high outflow resistance of the inner wall region. There is increasing evidence that the increase in TM outflow resistance in POAG is the result of a characteristic change in the biological properties of the resident cells in the JCT, which increasingly acquire the phenotype of contractile myofibroblasts. This scenario strengthens simultaneously both their actin cytoskeleton and their directly associated extracellular matrix fibrils, leads to overall stiffening of the tissue, and is modulated by transforming growth factor-β (TGF-β)/connective tissue growth factor (CTGF) signaling. Essentially comparable changes appear to occur in SC endothelial cells in glaucoma. Causative therapy concepts targeting the aqueous outflow pathways in glaucoma should aim at interfering with this process either by attenuating TM or SC stiffness, and/or by modulating TGF-β/CTGF signaling.

  14. Antibiotic sensitivity pattern of causative organisms of neonatal septicemia in an urban hospital of Bangladesh

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    Forhad Monjur


    Full Text Available Background: The information of the sensitivity pattern of the causative organisms is very important for effective control of septicemia in neonates. OBJECTIVE: To determine the proportion and profile of pathogenic bacteria in the blood cultures of the neonates with clinically suspected septicemia and their susceptibility pattern to antimicrobial agents for developing a unified antibiotic treatment protocol. Materials and Methods: A cross-sectional retrospective study was conducted over a period of 3 year and 4 months (39 months. The study included 1000 patients admitted in the selected hospital in Bangladesh. Blood samples for culture were taken aseptically before starting antibiotic therapy. Microorganisms were isolated and identified by standard microbiological processes which include colony morphology, Gram stain, and biochemical profiles. Antimicrobial sensitivity patterns were performed by Kirby-Bauer′s disc diffusion method against imipenem, ciprofloxacin, ceftazidime, chloramphenicol, netilmicin, gentamicin, ceftriaxone, aztreonam, cefotaxime, cephalexin, and ampicillin. Results: Among the patients, 633 (63.3% were males and 367 (36.7% were females. Blood cultures were found positive in 194 (19.4% neonates. The organisms isolated were Pseudomonas spp. (31.4%, Klebsiella pneumoniae (23.2%, Staphylococcus aureus (12.4%, Escherichia coli (7.2%, Acinatobactor (5.7%, Gram-negative Bacilli (4.1%, Flavobacterium spp. (3.6%, Serratia spp. (5.7%, Citrobacter fruendi (3.1%, Streptococcus species (2.6%, and Enterobacter spp. (1.0%. A majority of the bacterial isolates in neonatal sepsis were found sensitive to imipenem (91.8% and ciprofloxacin (57.2% and resistant to commonly used antibiotics, eg. ampicillin (96.4% and cephalexin (89.2%. Conclusion : The problem can be mitigated by careful selection and prudent use of available antibiotics.

  15. Differences in thoracic injury causation patterns between seat belt restrained children and adults. (United States)

    Arbogast, Kristy B; Locey, Caitlin M; Zonfrillo, Mark R


    The objective of this research was to delineate age-based differences in specific thoracic injury diagnoses for seat belt restrained rear seat occupants and describe the associated injury causation in order to provide insight into how the load of the seat belt is transferred to occupants of various sizes. Using data from the Crash Investigation Research and Engineering Network (CIREN), 20 cases of rear seated, lap and shoulder belt restrained occupants with AIS2+ thoracic injuries in frontal crashes were reviewed. Seven were children and adolescents age 8-15 years, 5 were 16-24 years, 3 were 25-54 years, and 5 were 55+ years. Six of the seven 8-15 year olds sustained injuries to the lung in the form of pulmonary contusion or pneumothorax. Only three of the seven sustained a skeletal (sternum or rib) fracture; only one of these three involved multiple ribs bilaterally. In contrast, four of the five 16-24 year olds sustained at least one rib fracture - often multiple and bilateral. The adult cohort (25+ years) was involved in predominantly more minor crashes; however they all sustained complex rib fractures - seven of the eight involved multiple ribs, four of the eight were also bilateral. Belt compression - either from the shoulder belt or the lap belt - was identified as the primary cause of the thoracic injuries. Often, there was clear evidence of the location of belt loading from AIS 1 chest contusions or abrasions. These findings have implications for age-based thoracic injury criteria suggesting that that different metrics may be needed for different age groups.

  16. Complete genome sequencing of two causative viruses of cassava mosaic disease in Ghana. (United States)

    Oteng-Frimpong, R; Levy, Y; Torkpo, S K; Danquah, E Y; Offei, S K; Gafni, Y


    Cassava mosaic disease (CMV), caused by one or a combination of cassava mosaic geminiviruses, is ranked among the most important constraints to profitable and efficient production of cassava. Effective control measures require in-depth knowledge of the viral causative agent. Using rolling-circle amplification and unique enzymes, the full genome of two species of cassava mosaic geminivirus isolated from infected cassava plants in Ghana were cloned into pCambia 1300 and pET-28b. The sequences of the genome were determined on an ABI sequencer and a pairwise comparison was performed with other cassava-infecting geminiviruses from different countries. It was revealed that cassava grown in Ghana is attacked by two species of geminivirus in either single or mixed infections. These are the African cassava mosaic virus (ACMV) and the East African cassava mosaic virus (EACMV)-like, with high sequence similarity of 94% and 80%, respectively, between the DNA-A and DNA-B components of each virus, and 66% and 41% similarity of the common region (CR) (for A and B accordingly). The DNA-A of ACMV and EACMV-like contained 2781 and 2800 nucleotides, respectively, while their DNA-B components had 2725 and 2734 nucleotides, respectively. ACMV DNA-A was over 97% similar to those of other ACMVs from the continent. In contrast, EACMV-like DNA-A was over 98% similar to the isolates from Cameroon and other West African countries, and less than 88% similar to other EACMV species. Thus ACMV and EACMV-like were named African cassava mosaic virus-Ghana and East African cassava mosaic Cameroon virus-Ghana. Computer analysis revealed that their genome arrangement follows the typical old world bipartite begomovirus genome. The association of these two species and their interaction might account for the severe symptoms observed on infected plants in the field and in the greenhouse.

  17. Conference on "Multidisciplinary approaches to nutritional problems". Symposium on "Diabetes and health". Challenges in the study of causation of obesity

    DEFF Research Database (Denmark)

    Sørensen, Thorkild I A


    Use of the energy balance equation for understanding the causation of obesity is discussed. Its basis on the thermodynamic laws is expressed in mathematical models for body-weight changes. Only a very small net energy surplus per time unit constitutes the energy deposition during weight gain...... in adipose tissue. These and various other limitations of the energy balance model warrant cautiousness in using the model in studies of obesity causation. Weight gain may be self-promoting and mathematical feedback models allowing estimation of such effects show that they are realistic. Predisposition...... concept of the 'obesogenic' environment is critically analysed. Finally, particular opportunities for the identification of the causes of the obesity epidemic by detailed analysis of an observed irregular development of the epidemic over long time periods are presented, and evidence for predisposition...

  18. Consistent Treatment of Variables and Causation Poses a Challenge for Behavioral Research Methods: A Commentary on Nesselroade and Molenaar (2016). (United States)

    Markus, Keith A


    Nesselroade and Molenaar presented the ideographic filter as a proposal for analyzing lawful regularities in behavioral research. The proposal highlights an inconsistency that poses a challenge for behavioral research more generally. One can distinguish a broadly Humean approach from a broadly non-Humean approach as they relate to variables and to causation. Nesselroade and Molenaar rejected a Humean approach to latent variables that characterizes them as nothing more than summaries of their manifest indicators. By contrast, they tacitly accepted a Humean approach to causes characterized as nothing more than summaries of their manifest causal effects. A non-Humean treatment of variables coupled with a Humean treatment of causation creates a theoretical tension within their proposal. For example, one can interpret the same model elements as simultaneously representing both variables and causes. Future refinement of the ideographic filter proposal to address this tension could follow any of a number of strategies.

  19. Targeted exon sequencing successfully discovers rare causative genes and clarifies the molecular epidemiology of Japanese deafness patients. (United States)

    Miyagawa, Maiko; Naito, Takehiko; Nishio, Shin-ya; Kamatani, Naoyuki; Usami, Shin-ichi


    Target exon resequencing using Massively Parallel DNA Sequencing (MPS) is a new powerful strategy to discover causative genes in rare Mendelian disorders such as deafness. We attempted to identify genomic variations responsible for deafness by massive sequencing of the exons of 112 target candidate genes. By the analysis of 216randomly selected Japanese deafness patients (120 early-onset and 96 late-detected), who had already been evaluated for common genes/mutations by Invader assay and of which 48 had already been diagnosed, we efficiently identified causative mutations and/or mutation candidates in 57 genes. Approximately 86.6% (187/216) of the patients had at least one mutation. Of the 187 patients, in 69 the etiology of the hearing loss was completely explained. To determine which genes have the greatest impact on deafness etiology, the number of mutations was counted, showing that those in GJB2 were exceptionally higher, followed by mutations in SLC26A4, USH2A, GPR98, MYO15A, COL4A5 and CDH23. The present data suggested that targeted exon sequencing of selected genes using the MPS technology followed by the appropriate filtering algorithm will be able to identify rare responsible genes including new candidate genes for individual patients with deafness, and improve molecular diagnosis. In addition, using a large number of patients, the present study clarified the molecular epidemiology of deafness in Japanese. GJB2 is the most prevalent causative gene, and the major (commonly found) gene mutations cause 30-40% of deafness while the remainder of hearing loss is the result of various rare genes/mutations that have been difficult to diagnose by the conventional one-by-one approach. In conclusion, target exon resequencing using MPS technology is a suitable method to discover common and rare causative genes for a highly heterogeneous monogenic disease like hearing loss.

  20. Refinements on the inferred causative faults of the great 2012 Indian Ocean earthquakes (United States)

    Revathy, P. M.; Rajendran, K.


    As the largest known intra-plate strike-slip events, the pair of 2012 earthquakes in the Wharton Basin is a rarity. Separated in time by 2 hours these events rouse interest also because of their short inter-event duration, complex rupture mechanism, and spatial-temporal proximity to the great 2004 Sumatra plate boundary earthquake. Reactivation of fossil ridge-transform pairs is a favoured mechanism for large oceanic plate earthquakes and their inherent geometry triggers earthquakes on conjugate fault systems, as observed previously in the Wharton Basin. The current debate is whether the ruptures occurred on the WNW-ESE paleo ridges or the NNE-SSW paleo transforms. Back-projection models give a complex rupture pattern that favours the WNW-ESE fault [1]. However, the static stress changes due to the 2004 Sumatra earthquake and 2005 Nias earthquake favour the N15°E fault [2]. We use the Teleseismic Body-Wave Inversion Program [3] and waveform data from Global Seismic Network, to obtain the best fit solutions using P and S-wave synthetic modelling. The preliminary P-wave analysis of both earthquakes gives source parameters that are consistent with the Harvard CMT solutions. The obtained slip distribution complies with the NNE-SSW transforms. Both these earthquakes triggered small tsunamis which appear as two distinctive pulses on 13 Indian Ocean tide gauges and buoys. Frequency spectra of the tsunami recordings from various azimuths provide additional constraint for the choice of the causative faults. References: [1] Yue, H., T. Lay, and K. D. Koper (2012), En echelon and orthogonal fault ruptures of the 11 April 2012 great intraplate earthquakes, Nature, 490, 245-249, doi:10.1038/nature11492 [2] Delescluse, M., N. Chamot-Rooke, R. Cattin, L. Fleitout, O. Trubienko and C. Vigny April 2012 intra-oceanic seismicity off Sumatra boosted by the Banda-Aceh megathrust, Nature, 490(2012), pp. 240-244, doi:10.1038/nature11520 [3] M. Kikuchi and H. Kanamori, Note on

  1. An efficient hybrid causative event-based approach for deriving the annual flood frequency distribution (United States)

    Thyer, Mark; Li, Jing; Lambert, Martin; Kuczera, George; Metcalfe, Andrew


    Flood extremes are driven by highly variable and complex climatic and hydrological processes. Derived flood frequency methods are often used to predict the flood frequency distribution (FFD) because they can provide predictions in ungauged catchments and evaluate the impact of land-use or climate change. This study presents recent work on development of a new derived flood frequency method called the hybrid causative events (HCE) approach. The advantage of the HCE approach is that it combines the accuracy of the continuous simulation approach with the computational efficiency of the event-based approaches. Derived flood frequency methods, can be divided into two classes. Event-based approaches provide fast estimation, but can also lead to prediction bias due to limitations of inherent assumptions required for obtaining input information (rainfall and catchment wetness) for events that cause large floods. Continuous simulation produces more accurate predictions, however, at the cost of massive computational time. The HCE method uses a short continuous simulation to provide inputs for a rainfall-runoff model running in an event-based fashion. A proof-of-concept pilot study that the HCE produces estimates of the flood frequency distribution with similar accuracy as the continuous simulation, but with dramatically reduced computation time. Recent work incorporated seasonality into the HCE approach and evaluated with a more realistic set of eight sites from a wide range of climate zones, typical of Australia, using a virtual catchment approach. The seasonal hybrid-CE provided accurate predictions of the FFD for all sites. Comparison with the existing non-seasonal hybrid-CE showed that for some sites the non-seasonal hybrid-CE significantly over-predicted the FFD. Analysis of the underlying cause of whether a site had a high, low or no need to use seasonality found it was based on a combination of reasons, that were difficult to predict apriori. Hence it is recommended

  2. Cystatin a, a potential common link for mutant myocilin causative glaucoma.

    Directory of Open Access Journals (Sweden)

    K David Kennedy

    Full Text Available Myocilin (MYOC is a 504 aa secreted glycoprotein induced by stress factors in the trabecular meshwork tissue of the eye, where it was discovered. Mutations in MYOC are linked to glaucoma. The glaucoma phenotype of each of the different MYOC mutation varies, but all of them cause elevated intraocular pressure (IOP. In cells, forty percent of wild-type MYOC is cleaved by calpain II, a cysteine protease. This proteolytic process is inhibited by MYOC mutants. In this study, we investigated the molecular mechanisms by which MYOC mutants cause glaucoma. We constructed adenoviral vectors with variants Q368X, R342K, D380N, K423E, and overexpressed them in human trabecular meshwork cells. We analyzed expression profiles with Affymetrix U133Plus2 GeneChips using wild-type and null viruses as controls. Analysis of trabecular meshwork relevant mechanisms showed that the unfolded protein response (UPR was the most affected. Search for individual candidate genes revealed that genes that have been historically connected to trabecular meshwork physiology and pathology were altered by the MYOC mutants. Some of those had known MYOC associations (MMP1, PDIA4, CALR, SFPR1 while others did not (EDN1, MGP, IGF1, TAC1. Some, were top-changed in only one mutant (LOXL1, CYP1B1, FBN1, others followed a mutant group pattern. Some of the genes were new (RAB39B, STC1, CXCL12, CSTA. In particular, one selected gene, the cysteine protease inhibitor cystatin A (CSTA, was commonly induced by all mutants and not by the wild-type. Subsequent functional analysis of the selected gene showed that CSTA was able to reduce wild-type MYOC cleavage in primary trabecular meshwork cells while an inactive mutated CSTA was not. These findings provide a new molecular understanding of the mechanisms of MYOC-causative glaucoma and reveal CSTA, a serum biomarker for cancer, as a potential biomarker and drug for the treatment of MYOC-induced glaucoma.

  3. Megazol and its bioisostere 4H-1,2,4-triazole: comparing the trypanocidal, cytotoxic and genotoxic activities and their in vitro and in silico interactions with the Trypanosoma brucei nitroreductase enzyme. (United States)

    Carvalho, Alcione Silva de; Salomão, Kelly; Castro, Solange Lisboa de; Conde, Taline Ramos; Zamith, Helena Pereira da Silva; Caffarena, Ernesto Raúl; Hall, Belinda Suzette; Wilkinson, Shane Robert; Boechat, Núbia


    Megazol (7) is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8) in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR) enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7) for nitrogen (in the triazole in 8), the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.

  4. Causative factors for formation of toxic islet amyloid polypeptide oligomer in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Jeong HR


    Full Text Available Hye Rin Jeong, Seong Soo A AnDepartment of Bionano Technology, Gachon Medical Research Institute, Gachon University, Gyeonggi-do, Republic of KoreaAbstract: Human islet amyloid polypeptide (h-IAPP is a peptide hormone that is synthesized and cosecreted with insulin from insulin-secreting pancreatic β-cells. Recently, h-IAPP was proposed to be the main component responsible for the cytotoxic pancreatic amyloid deposits in patients with type 2 diabetes mellitus (T2DM. Since the causative factors of IAPP (or amylin oligomer aggregation are not fully understood, this review will discuss the various forms of h-IAPP aggregation. Not all forms of IAPP aggregates trigger the destruction of β-cell function and loss of β-cell mass; however, toxic oligomers do trigger these events. Once these toxic oligomers form under abnormal metabolic conditions in T2DM, they can lead to cell disruption by inducing cell membrane destabilization. In this review, the various factors that have been shown to induce toxic IAPP oligomer formation will be presented, as well as the potential mechanism of oligomer and fibril formation from pro-IAPPs. Initially, pro-IAPPs undergo enzymatic reactions to produce the IAPP monomers, which can then develop into oligomers and fibrils. By this mechanism, toxic oligomers could be generated by diverse pathway components. Thus, the interconnections between factors that influence amyloid aggregation (eg, absence of PC2 enzyme, deamidation, reduction of disulfide bonds, environmental factors in the cell, genetic mutations, copper metal ions, and heparin will be presented. Hence, this review will aid in understanding the fundamental causative factors contributing to IAPP oligomer formation and support studies for investigating novel T2DM therapeutic approaches, such as the development of inhibitory agents for preventing oligomerization at the early stages of diabetic pathology.Keywords: amyloid aggregation, causative factor, IAPP, islet

  5. A comparative proteomic analysis reveals a new bi-lobe protein required for bi-lobe duplication and cell division in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Qing Zhou

    Full Text Available A Golgi-associated bi-lobed structure was previously found to be important for Golgi duplication and cell division in Trypanosoma brucei. To further understand its functions, comparative proteomics was performed on extracted flagellar complexes (including the flagellum and flagellum-associated structures such as the basal bodies and the bi-lobe and purified flagella to identify new bi-lobe proteins. A leucine-rich repeats containing protein, TbLRRP1, was characterized as a new bi-lobe component. The anterior part of the TbLRRP1-labeled bi-lobe is adjacent to the single Golgi apparatus, and the posterior side is tightly associated with the flagellar pocket collar marked by TbBILBO1. Inducible depletion of TbLRRP1 by RNA interference inhibited duplication of the bi-lobe as well as the adjacent Golgi apparatus and flagellar pocket collar. Formation of a new flagellum attachment zone and subsequent cell division were also inhibited, suggesting a central role of bi-lobe in Golgi, flagellar pocket collar and flagellum attachment zone biogenesis.

  6. The threonine degradation pathway of the Trypanosoma brucei procyclic form: the main carbon source for lipid biosynthesis is under metabolic control. (United States)

    Millerioux, Yoann; Ebikeme, Charles; Biran, Marc; Morand, Pauline; Bouyssou, Guillaume; Vincent, Isabel M; Mazet, Muriel; Riviere, Loïc; Franconi, Jean-Michel; Burchmore, Richard J S; Moreau, Patrick; Barrett, Michael P; Bringaud, Frédéric


    The Trypanosoma brucei procyclic form resides within the digestive tract of its insect vector, where it exploits amino acids as carbon sources. Threonine is the amino acid most rapidly consumed by this parasite, however its role is poorly understood. Here, we show that the procyclic trypanosomes grown in rich medium only use glucose and threonine for lipid biosynthesis, with threonine's contribution being ∼ 2.5 times higher than that of glucose. A combination of reverse genetics and NMR analysis of excreted end-products from threonine and glucose metabolism, shows that acetate, which feeds lipid biosynthesis, is also produced primarily from threonine. Interestingly, the first enzymatic step of the threonine degradation pathway, threonine dehydrogenase (TDH, EC, is under metabolic control and plays a key role in the rate of catabolism. Indeed, a trypanosome mutant deleted for the phosphoenolpyruvate decarboxylase gene (PEPCK, EC shows a 1.7-fold and twofold decrease of TDH protein level and activity, respectively, associated with a 1.8-fold reduction in threonine-derived acetate production. We conclude that TDH expression is under control and can be downregulated in response to metabolic perturbations, such as in the PEPCK mutant in which the glycolytic metabolic flux was redirected towards acetate production.

  7. The glycosylphosphatidylinositol-PLC in Trypanosoma brucei forms a linear array on the exterior of the flagellar membrane before and after activation. (United States)

    Hanrahan, Orla; Webb, Helena; O'Byrne, Robert; Brabazon, Elaine; Treumann, Achim; Sunter, Jack D; Carrington, Mark; Voorheis, H Paul


    Bloodstream forms of Trypanosoma brucei contain a glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) that cleaves the GPI-anchor of the variable surface glycoprotein (VSG). Its location in trypanosomes has been controversial. Here, using confocal microscopy and surface labelling techniques, we show that the GPI-PLC is located exclusively in a linear array on the outside of the flagellar membrane, close to the flagellar attachment zone, but does not co-localize with the flagellar attachment zone protein, FAZ1. Consequently, the GPI-PLC and the VSG occupy the same plasma membrane leaflet, which resolves the topological problem associated with the cleavage reaction if the VSG and the GPI-PLC were on opposite sides of the membrane. The exterior location requires the enzyme to be tightly regulated to prevent VSG release under basal conditions. During stimulated VSG release in intact cells, the GPI-PLC did not change location, suggesting that the release mechanism involves lateral diffusion of the VSG in the plane of the membrane to the fixed position of the GPI-PLC.

  8. `In crystallo' substrate binding triggers major domain movements and reveals magnesium as a co-activator of Trypanosoma brucei pyruvate kinase. (United States)

    Zhong, Wenhe; Morgan, Hugh P; McNae, Iain W; Michels, Paul A M; Fothergill-Gilmore, Linda A; Walkinshaw, Malcolm D


    The active site of pyruvate kinase (PYK) is located between the AC core of the enzyme and a mobile lid corresponding to domain B. Many PYK structures have already been determined, but the first `effector-only' structure and the first with PEP (the true natural substrate) are now reported for the enzyme from Trypanosoma brucei. PEP soaked into crystals of the enzyme with bound allosteric activator fructose 2,6-bisphosphate (F26BP) and Mg(2+) triggers a substantial 23° rotation of the B domain `in crystallo', resulting in a partially closed active site. The interplay of side chains with Mg(2+) and PEP may explain the mechanism of the domain movement. Furthermore, it is apparent that when F26BP is present but PEP is absent Mg(2+) occupies a position that is distinct from the two canonical Mg(2+)-binding sites at the active site. This third site is adjacent to the active site and involves the same amino-acid side chains as in canonical site 1 but in altered orientations. Site 3 acts to sequester Mg(2+) in a `priming' position such that the enzyme is maintained in its R-state conformation. In this way, Mg(2+) cooperates with F26BP to ensure that the enzyme is in a conformation that has a high affinity for the substrate.

  9. Coenzyme Q10 prevented full blown splenomegaly and decreased melarsoprol-induced reactive encephalopathy in mice infected with Trypanosoma brucei rhodesiense

    Institute of Scientific and Technical Information of China (English)

    James Nyabuga Nyariki; John Kibuthu Thuita; Grace Kemunto Nyambati; Alfred Orina Isaac


    Objective: To establish the modulatory effects of coenzyme Q10 on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalopathy (PTRE). Methods: Female Swiss white mice were orally administered with 200 mg/kg of coenzyme Q10 after which they were intraperitoneally inoculated with Trypanasoma brucei rhodesiense (T. b. rhodesiense). The resultant infection was allowed to develop and simulate all phases of human African trypanosomiasis and PTRE. Parasitaemia development, packed cell volume, haematological and pathological changes were determined. Results:A histological study in the brain tissue of T. b. rhodesiense infected mice demonstrated neuroinflammatory pathology which was highly amplified in the PTRE-induced groups. A prominent reduction in the severity of the neuroinflammatory response was detected when coenzyme-Q10 was administered. Furthermore, the mean tissue weight of spleen to body ratio in coenzyme Q10 supplemented group was significantly (P Conclusions: The capacity of coenzyme Q10 to alter the pathogenesis of T. b. rhodesiense infection in mice and following treatment with melarsoprol, may find application by rendering humans and animals less susceptible to deleterious effects of trypanosome infection such as splenomegaly and melarsoprol-induced PTRE and neurotoxicity.

  10. Depletion of the SR-Related Protein TbRRM1 Leads to Cell Cycle Arrest and Apoptosis-Like Death in Trypanosoma brucei (United States)

    Levy, Gabriela V.; Moretti, Georgina; Tekiel, Valeria S.; Sánchez, Daniel O.


    Arginine-Serine (RS) domain-containing proteins are RNA binding proteins with multiple functions in RNA metabolism. In mammalian cells this group of proteins is also implicated in regulation and coordination of cell cycle and apoptosis. In trypanosomes, an early branching group within the eukaryotic lineage, this group of proteins is represented by 3 members, two of them are SR proteins and have been recently shown to be involved in rRNA processing as well as in pre-mRNA splicing and stability. Here we report our findings on the 3rd member, the SR-related protein TbRRM1. In the present study, we showed that TbRRM1 ablation by RNA-interference in T. brucei procyclic cells leads to cell-cycle block, abnormal cell elongation compatible with the nozzle phenotype and cell death by an apoptosis-like mechanism. Our results expand the role of the trypanosomal RS-domain containing proteins in key cellular processes such as cell cycle and apoptosis-like death, roles also carried out by the mammalian SR proteins, and thus suggesting a conserved function in this phylogenetically conserved protein family. PMID:26284933

  11. No more "all or nothing": abandoning the Balance of Probability rule in cases of vague and subjective medical causation. (United States)

    Peled-Raz, Maya


    In March 2005, after several obiter rulings on this issue, the Supreme Court of Israel finally abandoned the "Balance of Probability" rule, finding it unjustifiable in situations of vague causation, and moved to use a statistical damages rule. According to this rule, when the cause of the damage cannot be proven for any vague medical (or any other scientific) reason, the plaintiff may meet his burden of proof by proving only a "significant" statistical probability, which may be lower than 50%, that the damage was caused by the defendant's negligent actions, although other external causes may be considered as likely or even more likely to be involved in the causation process. In cases when this burden of proof is met, the plaintiff would be compensated by a percentage of the total damage, equal to the percentage of the statistical probability proved. This ruling is a major change from the basic Balance of Probability rule, carrying with it a whole area of problems and questions, amongst which are questions as to the limits of its use and as to the basic justness and necessity of the Balance of Probability rule.

  12. Genetic diversity of the causative agent of ice-ice disease of the seaweed Kappaphycus alvarezii from Karimunjawa island, Indonesia (United States)

    Syafitri, E.; Prayitno, S. B.; Ma’ruf, W. F.; Radjasa, O. K.


    An essential step in investigating the bacterial role in the occurrence of diseases in Kappaphycus alvarezii is the characterization of bacteria associated with this seaweed. A molecular characterization was conducted on the genetic diversity of the causative agents of ice-ice disease associated with K. alvarezii widely known as the main source of kappa carrageenan. K. alvrezii infected with ice-ice were collected from the Karimunjawa island, North Java Sea, Indonesia. Using Zobell 2216E marine agar medium, nine bacterial species were isolated from the infected seaweed. The molecular characterizations revealed that the isolated bacteria causing ice-ice disease were closely related to the genera of Alteromonas, Bacillus, Pseudomonas, Pseudoalteromonas, Glaciecola, Aurantimonas, and Rhodococcus. In order to identify the symptoms causative organisms, the isolated bacterial species were cultured and were evaluated for their pathogenity. Out of 9 species, only 3 isolates were able to cause the ice-ice symptoms and consisted of Alteromonas macleodii, Pseudoalteromonas issachenkonii and Aurantimonas coralicida. A. macleodii showed the highest pathogenity.

  13. Causation mechanism analysis for haze pollution related to vehicle emission in Guangzhou, China by employing the fault tree approach. (United States)

    Huang, Weiqing; Fan, Hongbo; Qiu, Yongfu; Cheng, Zhiyu; Xu, Pingru; Qian, Yu


    Recently, China has frequently experienced large-scale, severe and persistent haze pollution due to surging urbanization and industrialization and a rapid growth in the number of motor vehicles and energy consumption. The vehicle emission due to the consumption of a large number of fossil fuels is no doubt a critical factor of the haze pollution. This work is focused on the causation mechanism of haze pollution related to the vehicle emission for Guangzhou city by employing the Fault Tree Analysis (FTA) method for the first time. With the establishment of the fault tree system of "Haze weather-Vehicle exhausts explosive emission", all of the important risk factors are discussed and identified by using this deductive FTA method. The qualitative and quantitative assessments of the fault tree system are carried out based on the structure, probability and critical importance degree analysis of the risk factors. The study may provide a new simple and effective tool/strategy for the causation mechanism analysis and risk management of haze pollution in China.

  14. DNA from protozoan parasites Babesia bovis, Trypanosoma cruzi, and T. brucei is mitogenic for B lymphocytes and stimulates macrophage expression of interleukin-12, tumor necrosis factor alpha, and nitric oxide. (United States)

    Shoda, L K; Kegerreis, K A; Suarez, C E; Roditi, I; Corral, R S; Bertot, G M; Norimine, J; Brown, W C


    The activation of innate immune responses by genomic DNA from bacteria and several nonvertebrate organisms represents a novel mechanism of pathogen recognition. We recently demonstrated the CpG-dependent mitogenic activity of DNA from the protozoan parasite Babesia bovis for bovine B lymphocytes (W. C. Brown, D. M. Estes, S. E. Chantler, K. A. Kegerreis, and C. E. Suarez, Infect. Immun. 66:5423-5432, 1998). However, activation of macrophages by DNA from protozoan parasites has not been demonstrated. The present study was therefore conducted to determine whether DNA from the protozan parasites B. bovis, Trypanosoma cruzi, and T. brucei activates macrophages to secrete inflammatory mediators associated with protective immunity. DNA from Escherichia coli and all three parasites stimulated B-lymphocyte proliferation and increased macrophage production of interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO). Regulation of IL-12 and NO production occurred at the level of transcription. The amounts of IL-12, TNF-alpha, and NO induced by E. coli and protozoal DNA were strongly correlated (r2 > 0.9) with the frequency of CG dinucleotides in the genome, and immunostimulation by DNA occurred in the order E. coli > or = T. cruzi > T. brucei > B. bovis. Induction of inflammatory mediators by E. coli, T. brucei, and B. bovis DNA was dependent on the presence of unmethylated CpG dinucleotides. However, at high concentrations, E. coli and T. cruzi DNA-mediated macrophage activation was not inhibited following methylation. The recognition of protozoal DNA by B lymphocytes and macrophages may provide an important innate defense mechanism to control parasite replication and promote persistent infection.

  15. Helminth parasites of cats from the Vientiane Province, Laos, as indicators of the occurrence of causative agents of human parasitoses

    Directory of Open Access Journals (Sweden)

    Scholz T.


    Full Text Available A total of 55 domestic cats (Felis calus f. domestico and one wild (Bengal cat (Prionailurus bengalensis from the Vientiane Province, central Laos, were examined for helminth parasites with emphasis given to potential human parasites. The following species were found (parasites infective to man marked with an asterisk: Opisthorchis viverrini*, Haplorchis pumilio*,H. laichui*,H. yokogawai*, Stellantchasmus falcatus* (Digenea; Spirometra sp.*, Dipylidium caninum*, Taenia taeniaeformis (Cestoda; Capillariidae gen. sp., Toxocara canis*, T. cati*, Ancylostoma ceylanicum*, A. tubaeforme, Gnathostoma spinigerum*, Physaloptera preputials (Nematoda; and Oncicola sp. (Acanthocephala. This study demonstrated that examination of cats may provide useful data on the occurrence of helminths which are potential causative agents of human diseases.

  16. Stevens Johnson syndrome, toxic epidermal necrolysis and SJS-TEN overlap: A retrospective study of causative drugs and clinical outcome

    Directory of Open Access Journals (Sweden)

    Sharma Vinod


    Full Text Available Background and Aims: Stevens Johnson syndrome (SJS, toxic epidermal necrolysis (TEN and SJS-TEN overlap are serious adverse cutaneous drug reactions. Drugs are often implicated in these reactions. Methods: A retrospective analysis of inpatients′ data with these dermatological diagnoses were carried out for three years, to study the causative drugs, clinical outcome, and mortality in these conditions. Results: Thirty patients (15 TEN, nine SJS-TEN overlap, and six SJS were admitted. In 21 cases, multiple drugs were implicated whereas single drugs were responsible in nine. Anticonvulsants (35.08% were the most commonly implicated drugs followed by antibiotics (33.33% and NSAIDS (24.56%. Twenty-five patients recovered whereas five died (four TEN, one SJS-TEN overlap. Conclusion: Anticonvulsants, antibiotics and NSAIDs were the most frequently implicated drugs. TEN causes higher mortality than both SJS and SJS-TEN overlap.


    Directory of Open Access Journals (Sweden)

    Shrivastava Bhanu


    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.

  18. Multilocus sequence typing and evolutionary relationships among the causative agents of melioidosis and glanders, Burkholderia pseudomallei and Burkholderia mallei. (United States)

    Godoy, Daniel; Randle, Gaynor; Simpson, Andrew J; Aanensen, David M; Pitt, Tyrone L; Kinoshita, Reimi; Spratt, Brian G


    A collection of 147 isolates of Burkholderia pseudomallei, B. mallei, and B. thailandensis was characterized by multilocus sequence typing (MLST). The 128 isolates of B. pseudomallei, the causative agent of melioidosis, were obtained from diverse geographic locations, from humans and animals with disease, and from the environment and were resolved into 71 sequence types. The utility of the MLST scheme for epidemiological investigations was established by analyzing isolates from captive marine mammals and birds and from humans in Hong Kong with melioidosis. MLST gave a level of resolution similar to that given by pulsed-field gel electrophoresis and identified the same three clones causing disease in animals, each of which was also associated with disease in humans. The average divergence between the alleles of B. thailandensis and B. pseudomallei was 3.2%, and there was no sharing of alleles between these species. Trees constructed from differences in the allelic profiles of the isolates and from the concatenated sequences of the seven loci showed that the B. pseudomallei isolates formed a cluster of closely related lineages that were fully resolved from the cluster of B. thailandensis isolates, confirming their separate species status. However, isolates of B. mallei, the causative agent of glanders, recovered from three continents over a 30-year period had identical allelic profiles, and the B. mallei isolates clustered within the B. pseudomallei group of isolates. Alleles at six of the seven loci in B. mallei were also present within B. pseudomallei isolates, and B. mallei is a clone of B. pseudomallei that, on population genetics grounds, should not be given separate species status.

  19. Mutual reinforcement between neuroticism and life experiences: a five-wave, 16-year study to test reciprocal causation. (United States)

    Jeronimus, Bertus F; Riese, Harriëtte; Sanderman, Robbert; Ormel, Johan


    High neuroticism predicts psychopathology and physical health problems. Nongenetic factors, including major life events and experiences, explain approximately half of the variance in neuroticism. Conversely, neuroticism also predicts these life experiences. In this study, we aimed to quantify the reciprocal causation between neuroticism and life experiences and to gauge the magnitude and persistence of these associations. This longitudinal cohort study included 5 assessment waves over 16 years in a random sample of 296 Dutch participants (47% women) with a mean age of 34 years (SD = 12, range 16-63 years). Neuroticism was assessed with the Amsterdam Biographic Questionnaire. The experiences measured included positive and negative life events, long-term difficulties (LTDs), and change in life quality, all assessed by contextual rating procedures adapted from the Life Event and Difficulties Schedule. We fit structural equation models in Mplus. Results showed that neuroticism consistently predicted negative experiences, decreased life quality, and LTDs (β = 0.15 to 0.39), whereas effects on positive experiences were variable (β = 0.14). LTDs and deteriorated life quality each predicted small but persistent increases in neuroticism (β = 0.18), whereas improved life quality predicted small but persistent decreases (β = -0.13). This suggests set point change in neuroticism. Life event aggregates showed no persistent effects on the neuroticism set point. Neuroticism and life experiences showed persistent, bidirectional associations. Experience-driven changes in neuroticism lasted over a decade. Results support the corresponsive principle (reciprocal causation), suggesting a mixed model of change in neuroticism that distinguishes temporary changes in neuroticism from persistent changes in an individual's neuroticism set point.

  20. Optimization of Causative Factors for Landslide Susceptibility Evaluation Using Remote Sensing and GIS Data in Parts of Niigata, Japan.

    Directory of Open Access Journals (Sweden)

    Jie Dou

    Full Text Available This paper assesses the potentiality of certainty factor models (CF for the best suitable causative factors extraction for landslide susceptibility mapping in the Sado Island, Niigata Prefecture, Japan. To test the applicability of CF, a landslide inventory map provided by National Research Institute for Earth Science and Disaster Prevention (NIED was split into two subsets: (i 70% of the landslides in the inventory to be used for building the CF based model; (ii 30% of the landslides to be used for the validation purpose. A spatial database with fifteen landslide causative factors was then constructed by processing ALOS satellite images, aerial photos, topographical and geological maps. CF model was then applied to select the best subset from the fifteen factors. Using all fifteen factors and the best subset factors, landslide susceptibility maps were produced using statistical index (SI and logistic regression (LR models. The susceptibility maps were validated and compared using landslide locations in the validation data. The prediction performance of two susceptibility maps was estimated using the Receiver Operating Characteristics (ROC. The result shows that the area under the ROC curve (AUC for the LR model (AUC = 0.817 is slightly higher than those obtained from the SI model (AUC = 0.801. Further, it is noted that the SI and LR models using the best subset outperform the models using the fifteen original factors. Therefore, we conclude that the optimized factor model using CF is more accurate in predicting landslide susceptibility and obtaining a more homogeneous classification map. Our findings acknowledge that in the mountainous regions suffering from data scarcity, it is possible to select key factors related to landslide occurrence based on the CF models in a GIS platform. Hence, the development of a scenario for future planning of risk mitigation is achieved in an efficient manner.

  1. Optimization of Causative Factors for Landslide Susceptibility Evaluation Using Remote Sensing and GIS Data in Parts of Niigata, Japan. (United States)

    Dou, Jie; Tien Bui, Dieu; Yunus, Ali P; Jia, Kun; Song, Xuan; Revhaug, Inge; Xia, Huan; Zhu, Zhongfan


    This paper assesses the potentiality of certainty factor models (CF) for the best suitable causative factors extraction for landslide susceptibility mapping in the Sado Island, Niigata Prefecture, Japan. To test the applicability of CF, a landslide inventory map provided by National Research Institute for Earth Science and Disaster Prevention (NIED) was split into two subsets: (i) 70% of the landslides in the inventory to be used for building the CF based model; (ii) 30% of the landslides to be used for the validation purpose. A spatial database with fifteen landslide causative factors was then constructed by processing ALOS satellite images, aerial photos, topographical and geological maps. CF model was then applied to select the best subset from the fifteen factors. Using all fifteen factors and the best subset factors, landslide susceptibility maps were produced using statistical index (SI) and logistic regression (LR) models. The susceptibility maps were validated and compared using landslide locations in the validation data. The prediction performance of two susceptibility maps was estimated using the Receiver Operating Characteristics (ROC). The result shows that the area under the ROC curve (AUC) for the LR model (AUC = 0.817) is slightly higher than those obtained from the SI model (AUC = 0.801). Further, it is noted that the SI and LR models using the best subset outperform the models using the fifteen original factors. Therefore, we conclude that the optimized factor model using CF is more accurate in predicting landslide susceptibility and obtaining a more homogeneous classification map. Our findings acknowledge that in the mountainous regions suffering from data scarcity, it is possible to select key factors related to landslide occurrence based on the CF models in a GIS platform. Hence, the development of a scenario for future planning of risk mitigation is achieved in an efficient manner.

  2. Trypanosoma brucei RNA binding proteins p34 and p37 mediate NOPP44/46 cellular localization via the exportin 1 nuclear export pathway. (United States)

    Hellman, Kristina; Prohaska, Kimberly; Williams, Noreen


    We have previously identified and characterized two novel nuclear RNA binding proteins, p34 and p37, which have been shown to interact with a family of nucleolar phosphoproteins, NOPP44/46, in Trypanosoma brucei. These proteins are nearly identical, the major difference being an 18-amino-acid insert in the N terminus of p37. In order to characterize the interaction between p34 and p37 and NOPP44/46, we have utilized an RNA interference (RNAi) cell line that specifically targets p34 and p37. Within these RNAi cells, we detected a disruption of a higher-molecular-weight complex containing NOPP44/46, as well as a dramatic increase in nuclear NOPP44/46 protein levels. We demonstrated that no change occurred in NOPP44/46 mRNA steady-state levels or stability, nor was there a change in cellular protein levels. These results led us to investigate whether p34 and p37 regulate NOPP44/46 cellular localization. Examination of the p34 and p37 amino acid sequences revealed a leucine-rich nuclear export signal, which interacts with the nuclear export factor exportin 1. Immune capture experiments demonstrated that p34, p37, and NOPP44/46 associate with exportin 1. When these experiments were performed with p34/p37 RNAi cells, NOPP44/46 no longer associated with exportin 1. Sequential immune capture experiments demonstrated that p34, p37, NOPP44/46, and exportin 1 exist in a common complex. Inhibiting exportin 1-mediated nuclear export led to an increase in nuclear NOPP44/46 proteins, indicating that they are exported from the nucleus via this pathway. Together, our results demonstrate that p34 and p37 regulate NOPP44/46 cellular localization by facilitating their association with exportin 1.

  3. Genome-wide expression profiling of in vivo-derived bloodstream parasite stages and dynamic analysis of mRNA alterations during synchronous differentiation in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Ghazal Peter


    Full Text Available Abstract Background Trypanosomes undergo extensive developmental changes during their complex life cycle. Crucial among these is the transition between slender and stumpy bloodstream forms and, thereafter, the differentiation from stumpy to tsetse-midgut procyclic forms. These developmental events are highly regulated, temporally reproducible and accompanied by expression changes mediated almost exclusively at the post-transcriptional level. Results In this study we have examined, by whole-genome microarray analysis, the mRNA abundance of genes in slender and stumpy forms of T.brucei AnTat1.1 cells, and also during their synchronous differentiation to procyclic forms. In total, five biological replicates representing the differentiation of matched parasite populations derived from five individual mouse infections were assayed, with RNAs being derived at key biological time points during the time course of their synchronous differentiation to procyclic forms. Importantly, the biological context of these mRNA profiles was established by assaying the coincident cellular events in each population (surface antigen exchange, morphological restructuring, cell cycle re-entry, thereby linking the observed gene expression changes to the well-established framework of trypanosome differentiation. Conclusion Using stringent statistical analysis and validation of the derived profiles against experimentally-predicted gene expression and phenotypic changes, we have established the profile of regulated gene expression during these important life-cycle transitions. The highly synchronous nature of differentiation between stumpy and procyclic forms also means that these studies of mRNA profiles are directly relevant to the changes in mRNA abundance within individual cells during this well-characterised developmental transition.

  4. Structure determination of glycogen synthase kinase-3 from Leishmania major and comparative inhibitor structure-activity relationships with Trypanosoma brucei GSK-3

    Energy Technology Data Exchange (ETDEWEB)

    Ojo, Kayode K; Arakaki, Tracy L; Napuli, Alberto J; Inampudi, Krishna K; Keyloun, Katelyn R; Zhang, Li; Hol, Wim G.J.; Verlind, Christophe L.M.J.; Merritt, Ethan A; Van Voorhis, Wesley C [UWASH


    Glycogen synthase kinase-3 (GSK-3) is a drug target under intense investigation in pharmaceutical companies and constitutes an attractive piggyback target for eukaryotic pathogens. Two different GSKs are found in trypanosomatids, one about 150 residues shorter than the other. GSK-3 short (GeneDB: Tb927.10.13780) has previously been validated genetically as a drug target in Trypanosoma brucei by RNAi induced growth retardation; and chemically by correlation between enzyme and in vitro growth inhibition. Here, we report investigation of the equivalent GSK-3 short enzymes of L. major (LmjF18.0270) and L. infantum (LinJ18_V3.0270, identical in amino acid sequences to LdonGSK-3 short) and a crystal structure of LmajGSK-3 short at 2 Å resolution. The inhibitor structure-activity relationships (SARs) of L. major and L. infantum are virtually identical, suggesting that inhibitors could be useful for both cutaneous and visceral leishmaniasis. Leishmania spp. GSK-3 short has different inhibitor SARs than TbruGSK-3 short, which can be explained mostly by two variant residues in the ATP-binding pocket. Indeed, mutating these residues in the ATP-binding site of LmajGSK-3 short to the TbruGSK-3 short equivalents results in a mutant LmajGSK-3 short enzyme with SAR more similar to that of TbruGSK-3 short. The differences between human GSK-3β (HsGSK-3β) and LmajGSK-3 short SAR suggest that compounds which selectively inhibit LmajGSK-3 short may be found.

  5. Micro RNA expression profiles in peripheral blood cells of rats that were experimentally infected with Trypanosoma congolense and different Trypanosoma brucei subspecies. (United States)

    Simo, Gustave; Lueong, Smiths; Grebaut, Pascal; Guny, Gerard; Hoheisel, Jörg D


    To identify miRNAs whose expression are differentially regulated during trypanosome infections a microarray targeting more than 600 rat miRNA was used to analyze the miRNA expression profiles between uninfected rats and animals infected by Trypanosoma congolense and Trypanosoma brucei s.l. The potential targets of dysregulated miRNAs as well as their biological pathways and functions were predicted using several bioinformatics software tools. Irrespective of the infecting trypanosome species, eight miRNAs (seven up- and one down-regulated) were dysregulated during infections. Moreover, other miRNAs were differentially regulated in rats infected by specific trypanosome species. Functional analyses of differentially regulated miRNAs indicated their involvement in diverse biological processes. Among these, transcription repressor activity, gene expression control as well as protein transporter activity were predominant. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of dysregulated miRNAs revealed their involvement in several biological pathways and disease conditions. This suggests possible modulation of such pathways following trypanosome infection; for example, the MAPK signaling pathway which is known to play vital roles in apoptosis, innate immune response and response to viral infections was highly affected. Axon guidance was equally highly impacted and may indicate a cross reactivity between pathogen proteins and guidance molecules representing one pathological mechanism as it has been observed with influenza HA. Furthermore, Ingenuity pathway analyses of dysregulated miRNAs and potential targets indicated strong association with inflammatory responses, cell death and survival as well as infectious diseases. The data generated here provide valuable information to understand the regulatory function of miRNAs during trypanosome infections. They improved our knowledge on host-parasite cross-talks and provide a framework for investigations to

  6. Molecular identification of a causative parasite species using formalin-fixed paraffin embedded (FFPE) tissues of a complicated human pulmonary sparganosis case without decisive clinical diagnosis. (United States)

    Koonmee, Supinda; Intapan, Pewpan M; Yamasaki, Hiroshi; Sugiyama, Hiromu; Muto, Maki; Kuramochi, Toshiaki; Kularbkeaw, Jurairat; Kanpittaya, Jaturat; Maleewong, Wanchai; Nawa, Yukifumi


    PCR-based molecular diagnosis was made for the identification of causative agents of the clinically suspected pulmonary proliferative sparganosis case found in Thailand using formalin-fixed paraffin-embedded (FFPE) biopsy specimens. As a reference, FFPE biopsy specimen from a typical cutaneous sparganosis case was examined together. DNA samples were extracted from tissues and two partial fragments of cytochrome c oxidase subunit 1 (cox1) gene were amplified for the detection of Spirometra DNA. Two cox1 fragments were amplified successfully for both specimens. After alignment of nucleotide sequences of the PCR-amplicons, the causative agents of both cases were identified as Spirometra erinaceieuropaei.

  7. 论环境侵权因果关系证明责任承担--对因果关系推定与因果关系证明责任倒置之区别的厘清%On the Burden of Proof on Causation in Environmental Tort--Clarifying the Difference Between the Causation Presumption and the Inversion of Burden of Proof on Causation

    Institute of Scientific and Technical Information of China (English)

    俞琳璐; 李茂平


      在因果关系推定的视域下,原告须先就损害行为与损害事实间的因果关系进行初步举证并达到一定程度的盖然性,然后才发生推定因果关系成立和证明责任倒置的效果。我国现行法采用的是因果关系证明责任倒置规则,证明要件从诉讼伊始就已经完成了分配,损害行为和所受损失由原告承担证明责任,而行为与损害间的因果关系则应当自始由被告来承担,故原告对因果关系提出“表面证据”或者“初步证据”并非被告举证证明因果关系不存在的证明责任倒置的前提%  Under the theory of causation presumption, the plaintiff must firstly bear the initial burden of proof on the causation between the tort and the losses and achieve a certain degree of probability, and then the causation is pre-sumed to be established and the burden of proof is inversed. However, China’s current law adopts the rule of the in-version of burden of proof on causation so the elements of proof are completely distributed at the very beginning of the proceedings, and the plaintiff bear the burden of proof on the tort and the losses and the defendant bear the burden of proof on causation from the very beginning of the proceedings. Therefore, the defendant’s burden of proof on causa-tion is not premised by the "prima facie evidence" or "preliminary evidence" of causation presented by the plaintiff.

  8. Causation or only correlation? Application of causal inference graphs for evaluating causality in nano-QSAR models (United States)

    Sizochenko, Natalia; Gajewicz, Agnieszka; Leszczynski, Jerzy; Puzyn, Tomasz


    In this paper, we suggest that causal inference methods could be efficiently used in Quantitative Structure-Activity Relationships (QSAR) modeling as additional validation criteria within quality evaluation of the model. Verification of the relationships between descriptors and toxicity or other activity in the QSAR model has a vital role in understanding the mechanisms of action. The well-known phrase ``correlation does not imply causation'' reflects insight statistically correlated with the endpoint descriptor may not cause the emergence of this endpoint. Hence, paradigmatic shifts must be undertaken when moving from traditional statistical correlation analysis to causal analysis of multivariate data. Methods of causal discovery have been applied for broader physical insight into mechanisms of action and interpretation of the developed nano-QSAR models. Previously developed nano-QSAR models for toxicity of 17 nano-sized metal oxides towards E. coli bacteria have been validated by means of the causality criteria. Using the descriptors confirmed by the causal technique, we have developed new models consistent with the straightforward causal-reasoning account. It was proven that causal inference methods are able to provide a more robust mechanistic interpretation of the developed nano-QSAR models.In this paper, we suggest that causal inference methods could be efficiently used in Quantitative Structure-Activity Relationships (QSAR) modeling as additional validation criteria within quality evaluation of the model. Verification of the relationships between descriptors and toxicity or other activity in the QSAR model has a vital role in understanding the mechanisms of action. The well-known phrase ``correlation does not imply causation'' reflects insight statistically correlated with the endpoint descriptor may not cause the emergence of this endpoint. Hence, paradigmatic shifts must be undertaken when moving from traditional statistical correlation analysis to causal

  9. Application of fault tree approach for the causation mechanism of urban haze in Beijing--Considering the risk events related with exhausts of coal combustion. (United States)

    Huang, Weiqing; Fan, Hongbo; Qiu, Yongfu; Cheng, Zhiyu; Qian, Yu


    Haze weather has become a serious environmental pollution problem which occurs in many Chinese cities. One of the most critical factors for the formation of haze weather is the exhausts of coal combustion, thus it is meaningful to figure out the causation mechanism between urban haze and the exhausts of coal combustion. Based on above considerations, the fault tree analysis (FAT) approach was employed for the causation mechanism of urban haze in Beijing by considering the risk events related with the exhausts of coal combustion for the first time. Using this approach, firstly the fault tree of the urban haze causation system connecting with coal combustion exhausts was established; consequently the risk events were discussed and identified; then, the minimal cut sets were successfully determined using Boolean algebra; finally, the structure, probability and critical importance degree analysis of the risk events were completed for the qualitative and quantitative assessment. The study results proved that the FTA was an effective and simple tool for the causation mechanism analysis and risk management of urban haze in China.

  10. Upper Secondary and First-Year University Students' Explanations of Animal Behaviour: To What Extent Are Tinbergen's Four Questions about Causation, Ontogeny, Function and Evolution, Represented? (United States)

    Pinxten, Rianne; Desclée, Mathieu; Eens, Marcel


    In 1963, the Nobel Prize-winning ethologist Niko Tinbergen proposed a framework for the scientific study of animal behaviour by outlining four questions that should be answered to have a complete understanding: causation, ontogeny, function and evolution. At present, Tinbergen's framework is still considered the best way to guide animal…

  11. Students' Big Three Personality Traits, Perceptions of Teacher Interpersonal Behavior, and Mathematics Achievement: An Application of the Model of Reciprocal Causation (United States)

    Charalampous, Kyriakos; Kokkinos, Constantinos M.


    The purpose of the present study was to investigate the application of the Model of Reciprocal Causation (MRC) in examining the relationship between student personality (personal factors), student-perceived teacher interpersonal behavior (environment), and Mathematics achievement (behavior), with the simultaneous investigation of mediating effects…

  12. A comparison of DNA extraction procedures for the detection of Mycobacterium ulcerans, the causative agent of Buruli ulcer, in clinical and environmental specimens

    DEFF Research Database (Denmark)

    Durnez, Lies; Stragier, Pieter; Roebben, Karen


    Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease in humans after tuberculosis and leprosy. Although the disease is associated with aquatic ecosystems, cultivation of the bacillus from the environment is difficult to achieve. Therefore, at ...

  13. Dissemination material template, Deliverable 2.2 of the H2020 project SafetyCube (Safety CaUsation, Benefits and Efficiency).

    NARCIS (Netherlands)

    Tros, M. & Houtenbos, M.


    Safety CaUsation, Benefits and Efficiency (SafetyCube) is a European Commission supported Horizon 2020 project with the objective of developing an innovative road safety Decision Support System (DSS) that will enable policy-makers and stakeholders to select and implement the most appropriate strateg

  14. Functional confirmation of PLAG1 as the candidate causative gene underlying major pleiotropic effects on body weight and milk characteristics (United States)

    Fink, Tania; Tiplady, Kathryn; Lopdell, Thomas; Johnson, Thomas; Snell, Russell G.; Spelman, Richard J.; Davis, Stephen R.; Littlejohn, Mathew D.


    A major pleiotropic quantitative trait locus (QTL) located at ~25 Mbp on bovine chromosome 14 affects a myriad of growth and developmental traits in Bos taurus and indicus breeds. These QTL have been attributed to two functional variants in the bidirectional promoter of PLAG1 and CHCHD7. Although PLAG1 is a good candidate for mediating these effects, its role remains uncertain given that these variants are also associated with expression of five additional genes at the broader locus. In the current study, we conducted expression QTL (eQTL) mapping of this region using a large, high depth mammary RNAseq dataset representing 375 lactating cows. Here we show that of the seven previously implicated genes, only PLAG1 and LYN are differentially expressed by QTL genotype, and only PLAG1 bears the same association signature of the growth and body weight QTLs. For the first time, we also report significant association of PLAG1 genotype with milk production traits, including milk fat, volume, and protein yield. Collectively, these data strongly suggest PLAG1 as the causative gene underlying this diverse range of traits, and demonstrate new effects for the locus on lactation phenotypes. PMID:28322319

  15. Textual research of Wudu earthquake in 186 B.C. in Gansu Province, China and discussion on its causative structure

    Institute of Scientific and Technical Information of China (English)

    YUAN Dao-yang; LEI Zhong-sheng; HE Wen-gui; XIONG Zhen; GE Wei-peng; LIU Xing-wang; LIU Bai-chi


    On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earthquake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake catalogs are not definite and amendments should be made. The heavily-damaged area of this earthquake should be located between Jugan township of Wudu County and Pingding township of Zhouqu County. Its epicenter should be in the vicinity of Lianghekou in Wudu County with a magnitude of about 7~7 1/4 and an intensity of about Ⅸ~Ⅹ. The major axis direction of the heavily-damaged area should be in the WNW direction that is approximately consistent with the strike of the middle-east segment of Diebu-Bailongjiang active fault zone, and the origin time should match up to that of the latest paleoearthquake event[before (83±46) B.C.] obtained by the trench investigation.Certain seismic rupture evidences are still preserved on this fault segment. Therefore, we propose on the basis of comprehensive analysis that the causative structure of the M7~7 1/4 Wudu earthquake in 186 B.C. Should be in the middle-east segment of Diebu-Bailongjiang active fault zone.

  16. Identification of 3-methylbutanoyl glycosides in green Coffea arabica beans as causative determinants for the quality of coffee flavors. (United States)

    Iwasa, Keiko; Setoyama, Daiki; Shimizu, Hiroaki; Seta, Harumichi; Fujimura, Yoshinori; Miura, Daisuke; Wariishi, Hiroyuki; Nagai, Chifumi; Nakahara, Koichi


    The quality of coffee green beans is generally evaluated by the sensory cupping test, rather than by chemical compound-based criteria. In this study, we examined the relationship between metabolites and cupping scores for 36 varieties of beans, using a nontargeted LC-MS-based metabolic profiling technique. The cupping score was precisely predicted with the metabolic information measured using LC-MS. Two markers that strongly correlated with high cupping scores were determined to be isomers of 3-methylbutanoyl disaccharides (3MDs; 0.01-0.035 g/kg of beans) by spectroscopic analyses after purification, and one of them was a novel structure. Further, both the 3MDs were determined to be precursors of 3-methylbutanoic acid that enhance the quality of coffee. The applicability of 3MDs as universal quality indicators was validated with another sample set. It was concluded that 3MDs are the causative metabolites determining beverage quality and can be utilized for green bean selection and as key compounds for improving the beverage quality.

  17. From secondary causes to artificial instruments: Pierre-Sylvain Régis's rethinking of scholastic accounts of causation. (United States)

    Sangiacomo, Andrea


    Although several of Descartes's disciples established occasionalism as the natural outcome of Cartesianism, Pierre-Sylvain Régis forcefully resisted this conclusion by developing an account of secondary causes in which God does not immediately intervene in the natural world. In order to understand this view, it has been argued that Régis melds Aquinas's concurrentism with the new, mechanist natural philosophy defended in Cartesian physics. In this paper, I contend that such a reading of Régis's position is misleading for our understanding of both his account of secondary causality and the relationship between medieval debates and seventeenth century natural philosophy. I show that Régis's account of secondary causality denies two fundamental features at the core of the account proposed by Aquinas, namely that God acts immediately in nature and that secondary causes are per se causes. I contend that Régis's view more closely resembles a specific account of artificial instrumental causality developed by Duns Scotus. The comparison with Scotus shows that Régis is still dealing with conceptual tools that can be traced back to the scholastic tradition. Yet, Régis implements these tools to establish an account of causation that is fundamentally irreconcilable with scholastic natural philosophy.

  18. Identification of Clostridium tyrobutyricum as the causative agent of late blowing in cheese by species-specific PCR amplification. (United States)

    Klijn, N; Nieuwenhof, F F; Hoolwerf, J D; van der Waals, C B; Weerkamp, A H


    Butyric acid fermentation, the late-blowing defect in cheese, caused by the outgrowth of clostridial spores present in raw milk, can create considerable loss of product, especially in the production of semihard cheeses like Gouda cheese, but also in grana and Gruyère cheeses. To demonstrate the causative relationship between Clostridium tyrobutyricum and late blowing in cheese, many cheesemaking experiments were performed to provoke this defect by using spores from several strains of the major dairy-related clostridia. A method of PCR amplification of a part of the 16S rRNA gene in combination with hybridization with species-specific DNA probes was developed to allow the specific detection of clostridial sequences in DNAs extracted from cheeses. The sensitivity was increased by using nested PCR. Late blowing was provoked in experimental cheeses with 28 of the 32 C. tyrobutyricum strains tested, whereas experimental cheeses made with spores from C. beijerinckii, C. butyricum, and C. sporogenes showed no signs of butyric acid fermentation. In all experimental and commercial cheeses with obvious signs of late blowing, DNA from C. tyrobutyricum was detected; in some cheeses, signals for C. beijerinckii were also found. It was concluded that only C. tyrobutyricum strains are able to cause butyric acid fermentation in cheese.

  19. Clinicoepidemiologic pattern of cutaneous leishmaniasis and molecular characterization of its causative agent in Hajjah governorate, northwest of Yemen. (United States)

    Mogalli, Nabil M; El Hossary, Shabaan S; Khatri, Mishri Lal; Mukred, Abdualdaim M; Kassem, Hala A; El Sawaf, Bahira M; Ramadan, Nadia F


    The clinicoepidemiologic profile of 143 cases (93 males and 50 females) with cutaneous leishmaniasis from 18 villages of Hajjah governorate, Yemen was studied. Dry-type lesions were seen in 98.6% and wet-type lesions in 1.4% of patients. Lesions were localized in all cases with different morphological patterns. Microscopic examination of Giemsa-stained slit smears revealed amastigotes in 74.1% of patients with dry-type lesions and 0% in patients with wet-type lesions. The burden of the parasites in the lesions was high indicating active transmission of the disease. Most cases were from villages with moderate altitude range (8001-1600m). All age groups were affected, but most cases were seen in ages from 5 to 15 years. Leishmania species identification was done for all cases by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The biopsic material was scraped from both Giemsa-stained and methanol-fixed smears. The molecular characterization of Leishmania species revealed Leishmania tropica as the causative agent of cutaneous leishmaniasis in Hajjah, Yemen. The risk factors associated with the transmission of the disease and recommendations for improving case detection were discussed.

  20. Gain-of-function mutations in the ALS8 causative gene VAPB have detrimental effects on neurons and muscles

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    Mario Sanhueza


    Amyotrophic Lateral Sclerosis (ALS is a motor neuron degenerative disease characterized by a progressive, and ultimately fatal, muscle paralysis. The human VAMP-Associated Protein B (hVAPB is the causative gene of ALS type 8. Previous studies have shown that a loss-of-function mechanism is responsible for VAPB-induced ALS. Recently, a novel mutation in hVAPB (V234I has been identified but its pathogenic potential has not been assessed. We found that neuronal expression of the V234I mutant allele in Drosophila (DVAP-V260I induces defects in synaptic structure and microtubule architecture that are opposite to those associated with DVAP mutants and transgenic expression of other ALS-linked alleles. Expression of DVAP-V260I also induces aggregate formation, reduced viability, wing postural defects, abnormal locomotion behavior, nuclear abnormalities, neurodegeneration and upregulation of the heat-shock-mediated stress response. Similar, albeit milder, phenotypes are associated with the overexpression of the wild-type protein. These data show that overexpressing the wild-type DVAP is sufficient to induce the disease and that DVAP-V260I is a pathogenic allele with increased wild-type activity. We propose that a combination of gain- and loss-of-function mechanisms is responsible for VAPB-induced ALS.


    Institute of Scientific and Technical Information of China (English)

    DONG Mei-ying; ZHENG Pei-qun; XUE Gen-yuan


    In this paper, we summarized the characteristics of tropical cyclones (TC) activity over the western North Pacific in 2004 and analyzed their causation. Compared with the normal, the annual frequency of TC in 2004 was slightly higher, tropical cyclones in 2004 had a longer life span and occurred in a concentrated period, the source of TC were situated eastward; in all tracks of TC, the recurvature tracks took up larger proportion, the landfall regions of TC were located northward, which concentrated from East China to Japan. The primary causes were revealed as follows. Firstly, the intensity and area of the western North Pacific subtropical high was stronger and larger than usual respectively, and its ridge was frequently in the form of cells and stretched northwestward. Secondly, the convergence of intertropical convergence zone (ITCZ) was reinforced and the convergence zone moved more eastward than average. Thirdly, the meridionality of the westerlies was larger than average and the cell-shaped ridge formed a saddle region,which is in favor of TC northward motion and recurature.

  2. Vaccination and Infection as Causative Factors in Japanese Patients With Rasmussen Syndrome: Molecular Mimicry and HLA Class I

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    Yukitoshi Takahashi


    Full Text Available Rasmussen syndrome is an intractable epilepsy with a putative causal relation with cellular and humoral autoimmunity. Almost half of the patients have some preceding causative factors, with infections found in 38.2%, vaccinations in 5.9% and head trauma in 8.9% of Japanese patients. In a patient with seizure onset after influenza A infections, cross-reaction of the patient's lymphocytes with GluRε2 and influenza vaccine components was demonstrated by lymphocyte stimulation test. Database analyses revealed that influenza A virus hemagglutinin and GluRε2 molecules contain peptides with the patient's HLA class I binding motif (HLA ࢤ A*0201. The relative risks of HLA class I genotypes for Rasmussen syndrome are 6.1 (A*2402, 6.4 (A*0201, 6.3 (A*2601 and 11.4 (B*4601. The relative risks of HLA class I-A and B haplotypes are infinity (A*2601+B*5401, 21.1 (A*2402+B*1501, 13.3 (A*2402+B*4801 and 5.1 (A*2402+B*5201. Some alleles and haplotypes of HLA class I may be the risk factors in Japanese patients. Cross-reactivity of cytotoxic T lymphocytes may contribute to the processes leading from infection to the involvement of CNS.

  3. Mid-Thoracic Spinal Injuries during Horse Racing: Report of 3 Cases and Review of Causative Factors and Prevention Measurements

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    Ioannis Triantafyllopoulos


    Full Text Available We report three cases of a rare pattern of mid-thoracic spine injuries after horse racing falls and discuss possible causative factors and prevention measurements to reduce injury rates in professional riding and racing. Three patients, 2 male and 1 female with a mean age of 28 years old, underwent surgical treatment for mid-thoracic fractures after professional equestrian activities. The ASIA scale was E in one patient, B in the other one and A in the third. Multilevel posterior fusion was used in two patients and somatectomy plus fusion in the other. Follow up evaluation included changing of the ASIA scale, functional outcome and participation in equestrian activities. One patient fully recovered after surgery. Two patients remained paraplegic despite early surgical treatment and prolonged rehabilitation therapy. All patients had ended their professional equestrian career. This report analyzes possible mechanisms of injury and the pattern of mid-thoracic spine fractures after professional horse riding injuries. Despite skill improvements and continued safety education for horse riding, prophylactic measures for both the head and the spine should be refined. According to our study, additional mid-thoracic spinal protection should be added.

  4. Cutaneous adverse drug reactions: clinical pattern and causative agents--a 6 year series from Chandigarh, India.

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    Sharma V


    Full Text Available AIM: To study the different clinical spectrum of cutaneous adverse drug reactions (ADR and to determine the causative drugs. MATERIALS & METHODS: A prospective, hospital based study was carried out over a period of 6 years recording various cutaneous ADR. RESULTS: A total of 500 patients with cutaneous ADR were enrolled in the study. The most common types of cutaneous ADR patterns were maculopapular rash (34.6%, fixed drug eruption (FDE (30% and urticaria (14%. The drugs most often incriminated for the various cutaneous ADR were antimicrobials (42.6%, anticonvulsants (22.2% and NSAIDs (18%. Anticonvulsants were implicated in 41.6% of maculopapular rashes. Sulfonamides accounted for 43.3% and NSAIDs for 30.7% of FDE. Urticaria was caused mainly by NSAIDs(24.3% and penicillins(20%. Anticonvulsants were responsible for 43.8% of life-threatening toxic epidermal necrolysis and Stevens Johnson syndrome. CONCLUSIONS: The clinical pattern and drugs causing cutaneous ADR are similar to those observed in other countries except for minor variations. Cutaneous ADR patterns and the drugs causing various reactions are changing every year, which may be due to the emergence of newer molecules and changing trends in the use of drugs.

  5. Probability of Causation for Space Radiation Carcinogenesis Following International Space Station, Near Earth Asteroid, and Mars Missions (United States)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Chappell, Lori J.


    Cancer risk is an important concern for International Space Station (ISS) missions and future exploration missions. An important question concerns the likelihood of a causal association between a crew members radiation exposure and the occurrence of cancer. The probability of causation (PC), also denoted as attributable risk, is used to make such an estimate. This report summarizes the NASA model of space radiation cancer risks and uncertainties, including improvements to represent uncertainties in tissue-specific cancer incidence models for never-smokers and the U.S. average population. We report on tissue-specific cancer incidence estimates and PC for different post-mission times for ISS and exploration missions. An important conclusion from our analysis is that the NASA policy to limit the risk of exposure-induced death to 3% at the 95% confidence level largely ensures that estimates of the PC for most cancer types would not reach a level of significance. Reducing uncertainties through radiobiological research remains the most efficient method to extend mission length and establish effective mitigators for cancer risks. Efforts to establish biomarkers of space radiation-induced tumors and to estimate PC for rarer tumor types are briefly discussed.

  6. Graded Causation and Defaults (United States)


    analysis, for example, in David Lewis’s classic paper “Causation” [Lewis 1973] (although he calls it simply “causation”). This relation has been of HP uses struc- tural equations. The intuition behind this definition, which goes back to Hume [1748], is that A is a cause of B if, had A at least Hume [1748, Section VIII], who said: We may define a cause to be an object followed by another, . . . , if the first object had not been

  7. 职业暴露和环境污染引起疾病的因果关系的判断:总体判断和个体判断%Causal Relationships between Occupational and Environmental Exposures and Injury: General Causation and Specific Causation

    Institute of Scientific and Technical Information of China (English)

    郑宁嘉; Ben Thomas


    Demonstration of a causal relationship between chemical exposure and injury in litigation of toxic tort cases is a key to winning the case in Court. To evaluate whether a case has merit, two levels of causations,general causation and specific causation, are considered."""" General causation"""" refers to the question, does exposure to the toxicant cause the type of injury.9 For example, does aluminum welding fume cause lung cancer.'? Bradford Hill' s nine criteria are used to analyze """"general causation."""" These criteria include strength of association, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, and analogy. """"Specific causation"""" refers to the question, did the Plaintiff's exposure to the toxicant cause the injury in this individual. For example, was Mr. Smith's lung cancer caused by his occupational exposure to aluminum welding fume.'? In court, the Judge and jury are asked to make a decision about specific causation, and award or deny damages accordingly. The expert witnesses testify as advisor to the court. As health consultants,we ask five questions to evaluate specific causation: 1 .Was the individual exposed to a toxicant, and if so,what was the dose (mute,concentration,duration,and frequency)?. 2.What is known about the toxicity of that chemical?. (e.g. ,What specific adverse effects have been associated with exposures to that toxicant.? How long does it take for symptoms to develop.'? What dose is required.'? The analyzing process of general causation is included in our question 2. ) 3. Did the symptoms claimed by this individual appear in a manner and time sequence that is consistent with what is known about the toxicity of the chemical.? 4. When exposure to the chemical ceased, did the symptoms get better or disappear in a manner and time sequence that is consistent with the known toxicology.'? 5. What other conditions or factors might have caused this symptom, and are they relevant to this

  8. In vitro and in vivo activities of 2-aminopyrazines and 2-aminopyridines in experimental models of human African trypanosomiasis. (United States)

    Vodnala, Suman K; Lundbäck, Thomas; Sjöberg, Birger; Svensson, Richard; Rottenberg, Martin E; Hammarström, Lars G J


    New drugs for the treatment of human African trypanosomiasis are urgently needed. A number of 2-aminopyrazines/2-aminopyridines were identified as promising leads following a focused screen of 5,500 compounds for Trypanosoma brucei subsp. brucei viability. Described compounds are trypanotoxic in the submicromolar range and show comparably low cytotoxicity on representative mammalian cell lines. Specifically, 6-([6-fluoro-3,4-dihydro-2H-1-benzopyran-4-yl)]oxy)-N-(piperidin-4-yl)pyrazin-2-amine (CBK201352) is trypanotoxic for T. brucei subsp. brucei, T. brucei subsp. gambiense, and T. brucei subsp. rhodesiense and is nontoxic to mammalian cell lines, and in vitro preclinical assays predict promising pharmacokinetic parameters. Mice inoculated intraperitoneally (i.p.) with 25 mg/kg CBK201352 twice daily for 10 days, starting on the day of infection with T. brucei subsp. brucei, show complete clearance of parasites for more than 90 days. Thus, CBK201352 and related analogs are promising leads for the development of novel treatments for human African trypanosomiasis.

  9. Design, synthesis and in vitro antikinetoplastid evaluation of N-acylated putrescine, spermidine and spermine derivatives. (United States)

    Jagu, Elodie; Djilali, Rachid; Pomel, Sébastien; Ramiandrasoa, Florence; Pethe, Stéphanie; Labruère, Raphaël; Loiseau, Philippe M; Blonski, Casimir


    A structure-activity relationship study on polyamine derivatives led to the synthesis and the determination of antikinetoplastid activity of 17 compounds. Among them, a spermidine derivative (compound 13) was specifically active in vitro against Leishmania donovani axenic amastigotes (IC50 at 5.4μM; Selectivity Index >18.5) and a spermine derivative (compound 28) specifically active against Trypanosoma brucei gambiense (IC50 at 1.9μM; Selectivity Index >52).

  10. Population Vulnerability and Disability in Kenya's Tsetse Fly Habitats


    Grady, Sue C.; Messina, Joseph P.; McCord, Paul F.


    BACKGROUND: Human African Trypanosomiasis (HAT), also referred to as sleeping sickness, and African Animal Trypanosomaisis (AAT), known as nagana, are highly prevalent parasitic vector-borne diseases in sub-Saharan Africa. Humans acquire trypanosomiasis following the bite of a tsetse fly infected with the protozoa Trypanosoma brucei (T.b.) spp. -i.e., T.b. gambiense in West and Central Africa and T.b. rhodesiense in East and Southern Africa. Over the last decade HAT diagnostic capacity to est...

  11. Cone photoreceptor sensitivities and unique hue chromatic responses: correlation and causation imply the physiological basis of unique hues.

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    Ralph W Pridmore

    Full Text Available This paper relates major functions at the start and end of the color vision process. The process starts with three cone photoreceptors transducing light into electrical responses. Cone sensitivities were once expected to be Red Green Blue color matching functions (to mix colors but microspectrometry proved otherwise: they instead peak in yellowish, greenish, and blueish hues. These physiological functions are an enigma, unmatched with any set of psychophysical (behavioral functions. The end-result of the visual process is color sensation, whose essential percepts are unique (or pure hues red, yellow, green, blue. Unique hues cannot be described by other hues, but can describe all other hues, e.g., that hue is reddish-blue. They are carried by four opponent chromatic response curves but the literature does not specify whether each curve represents a range of hues or only one hue (a unique over its wavelength range. Here the latter is demonstrated, confirming that opponent chromatic responses define, and may be termed, unique hue chromatic responses. These psychophysical functions also are an enigma, unmatched with any physiological functions or basis. Here both enigmas are solved by demonstrating the three cone sensitivity curves and the three spectral chromatic response curves are almost identical sets (Pearson correlation coefficients r from 0.95-1.0 in peak wavelengths, curve shapes, math functions, and curve crossover wavelengths, though previously unrecognized due to presentation of curves in different formats, e.g., log, linear. (Red chromatic response curve is largely nonspectral and thus derives from two cones. Close correlation combined with deterministic causation implies cones are the physiological basis of unique hues. This match of three physiological and three psychophysical functions is unique in color vision.

  12. Causative agent distribution and antibiotic therapy assessment among adult patients with community acquired pneumonia in Chinese urban population

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    Liu Yong


    Full Text Available Abstract Background Knowledge of predominant microbial patterns in community-acquired pneumonia (CAP constitutes the basis for initial decisions about empirical antimicrobial treatment, so a prospective study was performed during 2003–2004 among CAP of adult Chinese urban populations. Methods Qualified patients were enrolled and screened for bacterial, atypical, and viral pathogens by sputum and/or blood culturing, and by antibody seroconversion test. Antibiotic treatment and patient outcome were also assessed. Results Non-viral pathogens were found in 324/610 (53.1% patients among whom M. pneumoniae was the most prevalent (126/610, 20.7%. Atypical pathogens were identified in 62/195 (31.8% patients carrying bacterial pathogens. Respiratory viruses were identified in 35 (19% of 184 randomly selected patients with adenovirus being the most common (16/184, 8.7%. The nonsusceptibility of S. pneumoniae to penicillin and azithromycin was 22.2% (Resistance (R: 3.2%, Intermediate (I: 19.0% and 79.4% (R: 79.4%, I: 0%, respectively. Of patients (312 from whom causative pathogens were identified and antibiotic treatments were recorded, clinical cure rate with β-lactam antibiotics alone and with combination of a β-lactam plus a macrolide or with fluoroquinolones was 63.7% (79/124 and 67%(126/188, respectively. For patients having mixed M. pneumoniae and/or C. pneumoniae infections, a better cure rate was observed with regimens that are active against atypical pathogens (e.g. a β-lactam plus a macrolide, or a fluoroquinolone than with β-lactam alone (75.8% vs. 42.9%, p = 0.045. Conclusion In Chinese adult CAP patients, M. pneumoniae was the most prevalent with mixed infections containing atypical pathogens being frequently observed. With S. pneumoniae, the prevalence of macrolide resistance was high and penicillin resistance low compared with data reported in other regions.

  13. A strategy for the proliferation of Ulva prolifera, main causative species of green tides, with formation of sporangia by fragmentation.

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    Shan Gao

    Full Text Available Ulva prolifera, a common green seaweed, is one of the causative species of green tides that occurred frequently along the shores of Qingdao in 2008 and had detrimental effects on the preparations for the 2008 Beijing Olympic Games sailing competition, since more than 30 percent of the area of the games was invaded. In view of the rapid accumulation of the vast biomass of floating U. prolifera in green tides, we investigated the formation of sporangia in disks of different diameters excised from U. prolifera, changes of the photosynthetic properties of cells during sporangia formation, and development of spores. The results suggested that disks less than 1.00 mm in diameter were optimal for the formation of sporangia, but there was a small amount of spore release in these. The highest percentage of area of spore release occurred in disks that were 2.50 mm in diameter. In contrast, sporangia were formed only at the cut edges of larger disks (3.00 mm, 3.50 mm, and 4.00 mm in diameter. Additionally, the majority of spores liberated from the disks appeared vigorous and developed successfully into new individuals. These results implied that fragments of the appropriate size from the U. prolifera thalli broken by a variety of factors via producing spores gave rise to the rapid proliferation of the seaweed under field conditions, which may be one of the most important factors to the rapid accumulation of the vast biomass of U. prolifera in the green tide that occurred in Qingdao, 2008.

  14. The in vitro antifungal activity of sudanese medicinal plants against Madurella mycetomatis, the eumycetoma major causative agent.

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    Hassabelrasoul Elfadil


    Full Text Available Eumycetoma is a debilitating chronic inflammatory fungal infection that exists worldwide but it is endemic in many tropical and subtropical regions. The major causative organism is the fungus Madurella mycetomatis. The current treatment of eumycetoma is suboptimal and characterized by low cure rate and high recurrence rates. Hence, an alternative therapy is needed to address this. Here we determined the antifungal activity of seven Sudanese medicinal plant species against Madurella mycetomatis. Of these, only three species; Boswellia papyrifera, Acacia nubica and Nigella sativa, showed some antifungal activity against M. mycetomatis and were further studied. Crude methanol, hexane and defatted methanol extracts of these species were tested for their antifungal activity. B. papyrifera had the highest antifungal activity (MIC50 of 1 ug/ml and it was further fractionated. The crude methanol and the soluble ethyl acetate fractions of B. papyrifera showed some antifungal activity. The Gas-Liquid-Chromatography hybrid Mass-Spectrophotometer analysis of these two fractions showed the existence of beta-amyrin, beta-amyrone, beta-Sitosterol and stigmatriene. Stigmatriene had the best antifungal activity, compared to other three phytoconstituents, with an MIC-50 of 32 μg/ml. Although the antifungal activity of the identified phytoconstituents was only limited, the antifungal activity of the complete extracts is more promising, indicating synergism. Furthermore these plant extracts are also known to have anti-inflammatory activity and can stimulate wound-healing; characteristics which might also be of great value in the development of novel therapeutic drugs for this chronic inflammatory disease. Therefore further exploration of these plant species in the treatment of mycetoma is encouraging.

  15. Causation analysis of hydrogen sulfide in Ansai oilfield%安塞油田硫化氢成因研究

    Institute of Scientific and Technical Information of China (English)

    张昊; 俞英


    Hydrogen sulfide is a kind of toxic gas which widely coexisted in oil field gas. The argument of hydrogen sulfide causation in oil field is mainly being concluded as Sulfur Bacteria Reduction (SBR) and Thermal Sulfate Reduction (TSR). The paper estimated the pos-sibilities of hydrogen sulfide production from reaction of hydrocarbons and alkaline earth metal sulfates by thermodynamics and concluded that the hydrogen sulfide can be produced at the condition of typical temperature and pressure of oil well underground. Combine with the results of water and mineral core analysis under well, the paper suggests that, at the condition of Ansai oil field, the hydrogen sulfide must be come from TSR result and SBR is unlikely the reasons.%硫化氢是石油伴生气中的有害成分之一。目前有关油气田伴生硫化氢的成因,存在着生物成因(SBR)、热化学成因(TsR)两种不同观点。本文从安塞油田地质环境条件下的烃类与岩心中的金属硫酸盐反应热力学分析,探讨了石油生产过程中硫化氢产生的可能机理,并结合地层水质分析及岩心分析结果,发现在安塞油田地质条件下,井下缺少微生物活动的必要条件,从而排除了BSR成因的可能性,论证了TSR成因应为安塞油田硫化氢产生的主要原因。

  16. Lead optimization of a pyrazole sulfonamide series of Trypanosoma brucei N-myristoyltransferase inhibitors: identification and evaluation of CNS penetrant compounds as potential treatments for stage 2 human African trypanosomiasis. (United States)

    Brand, Stephen; Norcross, Neil R; Thompson, Stephen; Harrison, Justin R; Smith, Victoria C; Robinson, David A; Torrie, Leah S; McElroy, Stuart P; Hallyburton, Irene; Norval, Suzanne; Scullion, Paul; Stojanovski, Laste; Simeons, Frederick R C; van Aalten, Daan; Frearson, Julie A; Brenk, Ruth; Fairlamb, Alan H; Ferguson, Michael A J; Wyatt, Paul G; Gilbert, Ian H; Read, Kevin D


    Trypanosoma brucei N-myristoyltransferase (TbNMT) is an attractive therapeutic target for the treatment of human African trypanosomiasis (HAT). From previous studies, we identified pyrazole sulfonamide, DDD85646 (1), a potent inhibitor of TbNMT. Although this compound represents an excellent lead, poor central nervous system (CNS) exposure restricts its use to the hemolymphatic form (stage 1) of the disease. With a clear clinical need for new drug treatments for HAT that address both the hemolymphatic and CNS stages of the disease, a chemistry campaign was initiated to address the shortfalls of this series. This paper describes modifications to the pyrazole sulfonamides which markedly improved blood-brain barrier permeability, achieved by reducing polar surface area and capping the sulfonamide. Moreover, replacing the core aromatic with a flexible linker significantly improved selectivity. This led to the discovery of DDD100097 (40) which demonstrated partial efficacy in a stage 2 (CNS) mouse model of HAT.

  17. Development and Evaluation of a Molecular Diagnostic Method for Rapid Detection of Histoplasma capsulatum var. farciminosum, the Causative Agent of Epizootic Lymphangitis, in Equine Clinical Samples


    Scantlebury, C. E.; Pinchbeck, G.L.; Loughnane, P.; Aklilu, N.; Ashine, T.; Stringer, A. P.; Gordon, L.; Marshall, M; Christley, R.M.; McCarthy, A. J.


    Histoplasma capsulatum var. farciminosum, the causative agent of epizootic lymphangitis (EZL), is endemic in parts of Africa. Diagnosis based on clinical signs and microscopy lacks specificity and is a barrier to further understanding this neglected disease. Here, a nested PCR method targeting the internal transcribed spacer (ITS) region of the rRNA operon was validated for application to equine clinical samples. Twenty-nine horses with signs of EZL from different climatic regions of Ethiopia...

  18. Association study between Van der Woude Syndrome causative gene GRHL3 and nonsyndromic cleft lip with or without cleft palate in a Chinese cohort. (United States)

    Wang, Yirui; Sun, Yimin; Huang, Yongqing; Pan, Yongchu; Jia, Zhonglin; Ma, Lijuan; Ma, Lan; Lan, Feifei; Zhou, Yuxi; Shi, Jiayu; Yang, Xiong; Zhang, Lei; Jiang, Hongbing; Jiang, Min; Yin, Aihua; Cheng, Jing; Wang, Lin; Yang, Yinxue; Shi, Bing


    Cleft lip with or without cleft palate (CL/P) is one of the most common birth defects worldwide and is characterized by abnormalities of the orofacial structure. Syndromic CL/P is mainly caused by Mendelian disorders such as Van der Woude Syndrome (VWS). However, >70% of CL/P cases are nonsyndromic, characterized by isolated orofacial cleft without any known syndrome. The etiology of nonsyndromic CL/P (NSCL/P) remains elusive, but it has been suggested that causative genes of syndromic CL/P might also contribute to NSCL/P. As such, the VWS causative gene IRF6 has been extensively studied in NSCL/P. Recently, GRHL3 was identified as another VWS causative gene. Thus, it may be a novel candidate gene for NSCL/P. In the present study, we genotyped 10 tag SNPs covering GRHL3 and performed association analysis with NSCL/P in 504 cases and 455 healthy controls. Our preliminary results identified rs10903078, rs4638975, and a haplotype rs10903078-rs6659209 of GRHL3 that exceeded the significance threshold (p<0.05), though none survived Bonferroni correction for multiple comparisons. As the first study between GRHL3 and NSCL/P, the contribution of this gene to NSCL/P etiology should be interpreted with caution based on existing evidence. Further, the robustness of association between GRHL3 and NSCL/P should be further validated in expanded cohorts.

  19. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera Queens and an Exploration of Potential Causative Factors.

    Directory of Open Access Journals (Sweden)

    Jeffery S Pettis

    linked to colony performance and laboratory and field data provide evidence that temperature extremes are a potential causative factor.

  20. The complete genome sequence of Yersinia pseudotuberculosis IP31758, the causative agent of Far East scarlet-like fever.

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    Mark Eppinger


    Full Text Available The first reported Far East scarlet-like fever (FESLF epidemic swept the Pacific coastal region of Russia in the late 1950s. Symptoms of the severe infection included erythematous skin rash and desquamation, exanthema, hyperhemic tongue, and a toxic shock syndrome. The term FESLF was coined for the infection because it shares clinical presentations with scarlet fever caused by group A streptococci. The causative agent was later identified as Yersinia pseudotuberculosis, although the range of morbidities was vastly different from classical pseudotuberculosis symptoms. To understand the origin and emergence of the peculiar clinical features of FESLF, we have sequenced the genome of the FESLF-causing strain Y. pseudotuberculosis IP31758 and compared it with that of another Y. pseudotuberculosis strain, IP32953, which causes classical gastrointestinal symptoms. The unique gene pool of Y pseudotuberculosis IP31758 accounts for more than 260 strain-specific genes and introduces individual physiological capabilities and virulence determinants, with a significant proportion horizontally acquired that likely originated from Enterobacteriaceae and other soil-dwelling bacteria that persist in the same ecological niche. The mobile genome pool includes two novel plasmids phylogenetically unrelated to all currently reported Yersinia plasmids. An icm/dot type IVB secretion system, shared only with the intracellular persisting pathogens of the order Legionellales, was found on the larger plasmid and could contribute to scarlatinoid fever symptoms in patients due to the introduction of immunomodulatory and immunosuppressive capabilities. We determined the common and unique traits resulting from genome evolution and speciation within the genus Yersinia and drew a more accurate species border between Y. pseudotuberculosis and Y. pestis. In contrast to the lack of genetic diversity observed in the evolutionary young descending Y. pestis lineage, the population

  1. 寻常型银屑病诱发因素分析%Causative Factors of Psoriasis Vulgaris

    Institute of Scientific and Technical Information of China (English)

    魏瑾; 刘梅; 肖汀; 曲乐; 陈洪铎; 何春涤


    Objective To investigate the causative factors of psoriasis vulgaris. Methods A total of 426 psoriasis vulgaris patients and 500 healthy subjects were enrolled. Through the method of case control study, single factor analysis and multi-factor analysis on ten factors of the case group and the control group subjects were carried out. Results It was showed by single factor analysis that damp conditions, infection, wound, drinking, fish and shrimp, drugs, mental stress and smoke were all among the risk factors of psoriasis with significant differences between the case and the control group ( P < 0.05 ) . Multi - factor analysis revealed that all the factors mentioned above contributed to the pathogenesis of psoriasis vulgaris except for drugs ( P <0.05 ) . Conclusion A number of environmental factors contribute to the development of psoriasis vulgaris.%目的 探讨寻常型银屑病的诱发因素.方法 选取426例寻常型银屑病患者(病例组)和500例健康者(对照组).应用病例对照研究方法,对两组受检者的10种因素进行单因素和多因素分析.结果 单因素分析显示,受潮、感染、外伤、饮酒、食鱼虾、药物、精神紧张及吸烟的患者在病例组、对照组中差异有统计学意义(P<0.05).多元Logistic回归分析显示,除了药物外,其他因素均是寻常型银屑病的诱发因素(P<0.05).结论 多种环境因素在寻常型银屑病的发生、发展中起重要作用.

  2. Characterization of glycans in the developmental stages of Myxobolus cerebralis (Myxozoa), the causative agent of whirling disease. (United States)

    Kaltner, H; Stippl, M; Knaus, M; El-Matbouli, M


    Glycans and sugar-binding molecules (lectins) form an interactive recognition system, which may enable parasitic organisms to adhere to host cells and migrate into target tissues. The aim of the present study was to analyse surface-associated glycans in the developmental stages of Myxobolus cerebralis (Hofer), the causative agent of whirling disease. A panel of biotin-labelled plant lectins was used to detect a broad spectrum of glycan motifs with high specificity. Binding sites were detected histochemically in the tissue sections of infected rainbow trout, Oncorhynchus mykiss (Walbaum), and infected Tubifex tubifex (Müller), and were characterized by light, fluorescence and transmission electron microscopy. With mannose-specific lectins [Lens culinaris agglutinin, Pisum sativum agglutinin, Canavalia ensiformis agglutinin (LCA, PSA, CanA)] mannose-containing glycans were detected in all the developmental stages and host tissues. No binding sites for galactose-specific lectins were present in M. cerebralis spores but reactivity with host tissues occurred. Diversity in glycans was detected by N-acetyl-D-galactosamine-specific lectins in sporoplasm cells of M. cerebralis and triactinomyxon spores. In the group of lectins with monosaccharide-specificity for N-acetyl-D-glucosamine (GlcNAc), the reactivity of Datura stramonium agglutinin (DSA), Lycopersicon esculentum agglutinin (LEA) and Solanum tuberosum agglutinin (STA) was restricted to polar capsules whereas Griffonia simplicifolia agglutinin II (GSA II) also bound to sporoplasm cells of stages in the fish host but not in those present in infected T. tubifex. Moreover, Triticum vulgaris (wheat germ) agglutinin (WGA) and succinylated WGA indicated the presence of N-acetyl-D-glucosamine polymers in polar capsules. No specificity for spores was observed concerning 'bisected'N-glycans and no reactivity in parasitic stages was observed with the fucose-binding lectin Ulex europaeus agglutinin (UEA) I, Sambucus nigra

  3. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera) Queens and an Exploration of Potential Causative Factors. (United States)

    Pettis, Jeffery S; Rice, Nathan; Joselow, Katie; vanEngelsdorp, Dennis; Chaimanee, Veeranan


    colony performance and laboratory and field data provide evidence that temperature extremes are a potential causative factor.

  4. Colony Failure Linked to Low Sperm Viability in Honey Bee (Apis mellifera) Queens and an Exploration of Potential Causative Factors (United States)

    Pettis, Jeffery S.; Rice, Nathan; Joselow, Katie; vanEngelsdorp, Dennis; Chaimanee, Veeranan


    colony performance and laboratory and field data provide evidence that temperature extremes are a potential causative factor. PMID:26863438

  5. Adaptation of Trypanosoma rhodesiense to hypohaptoglobinaemic serum requires transcription of the APOL1 resistance gene in a RNA polymerase I locus. (United States)

    Lecordier, Laurence; Uzureau, Pierrick; Tebabi, Patricia; Brauner, Jonathan; Benghiat, Fleur Samantha; Vanhollebeke, Benoit; Pays, Etienne


    Human apolipoprotein L1 (APOL1) kills African trypanosomes except Trypanosoma rhodesiense and Trypanosoma gambiense, the parasites causing sleeping sickness. APOL1 uptake into trypanosomes is favoured by its association with the haptoglobin-related protein-haemoglobin complex, which binds to the parasite surface receptor for haptoglobin-haemoglobin. As haptoglobin-haemoglobin can saturate the receptor, APOL1 uptake is increased in haptoglobin-poor (hypohaptoglobinaemic) serum (HyHS). While T. rhodesiense resists APOL1 by RNA polymerase I (pol-I)-mediated expression of the serum resistance-associated (SRA) protein, T. gambiense resists by pol-II-mediated expression of the T. gambiense-specific glycoprotein (TgsGP). Moreover, in T. gambiense resistance to HyHS is linked to haptoglobin-haemoglobin receptor inactivation by mutation. We report that unlike T. gambiense, T. rhodesiense possesses a functional haptoglobin-haemoglobin receptor, and that like T. gambiense experimentally provided with active receptor, this parasite is killed in HyHS because of receptor-mediated APOL1 uptake. However, T. rhodesiense could adapt to low haptoglobin by increasing transcription of SRA. When assayed in Trypanosoma brucei, resistance to HyHS occurred with pol-I-, but not with pol-II-mediated SRA expression. Similarly, T. gambiense provided with active receptor acquired resistance to HyHS only when TgsGP was moved to a pol-I locus. Thus, transcription by pol-I favours adaptive gene regulation, explaining the presence of SRA in a pol-I locus.

  6. Squalamine analogues as potential anti-trypanosomal and anti-leishmanial compounds. (United States)

    Khabnadideh, S; Tan, C L; Croft, S L; Kendrick, H; Yardley, V; Gilbert, I H


    This paper concerns the synthesis of various simplified analogues of the novel anti-microbial agent, squalamine. The compounds were then investigated for activity against Trypanosoma brucei, the causative agent of African trypanosomiasis, Trypanosoma cruzi, the causative agent of Chagas disease and Leishmania donovani, the causative agent of visceral leishmaniasis. Several compounds showed in vitro activity, especially against T. brucei and L. donovani. However, one compound showed poor in vivo activity.

  7. Climate change impacts: The challenge of quantifying multi-factor causation, multi-component responses, and leveraging from extremes (United States)

    Field, C. B.


    Modeling climate change impacts is challenging for a variety of reasons. Some of these are related to causation. A weather or climate event is rarely the sole cause of an impact, and, for many impacts, social, economic, cultural, or ecological factors may play a larger role than climate. Other challenges are related to outcomes. Consequences of an event are often most severe when several kinds of responses interact, typically in unexpected ways. Many kinds of consequences are difficult to quantify, especially when they include a mix of market, cultural, personal, and ecological values. In addition, scale can be tremendously important. Modest impacts over large areas present very different challenges than severe but very local impacts. Finally, impacts may respond non-linearly to forcing, with behavior that changes qualitatively at one or more thresholds and with unexpected outcomes in extremes. Modeling these potentially complex interactions between drivers and impacts presents one set of challenges. Evaluating the models presents another. At least five kinds of approaches can contribute to the evaluation of impact models designed to provide insights in multi-driver, multi-responder, multi-scale, and extreme-driven contexts, even though none of these approaches is a complete or "silver-bullet" solution. The starting point for much of the evaluation in this space is case studies. Case studies can help illustrate links between processes and scales. They can highlight factors that amplify or suppress sensitivity to climate drivers, and they can suggest the consequences of intervening at different points. While case studies rarely provide concrete evidence about mechanisms, they can help move a mechanistic case from circumstantial to sound. Novel approaches to data collection, including crowd sourcing, can potentially provide tools and the number of relevant examples to develop case studies as statistically robust data sources. A critical condition for progress in this

  8. Trends in peptic ulcer disease and the identification of Helicobacter Pylori as a causative organism: Population-based estimates from the US nationwide inpatient sample

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    Bronislava Bashinskaya


    Full Text Available Background: Peptic ulcer disease can lead to serious complications including massive hemorrhage or bowel perforation. The modern treatment of peptic ulcer disease has transitioned from the control of gastric acid secretion to include antibiotic therapy in light of the identification of Helicobacter pylori as a causative infectious organism. We sought to determine trends related to this discovery by using a national database. Materials and Methods: Patient discharges with peptic ulcer disease and associated sequelae were queried from the Nationwide Inpatient Sample, 1993 to 2007, under the auspices of a data user agreement. To account for the Nationwide Inpatient Sample weighting schema, design-adjusted analyses were used. Standard error was calculated using SUDAAN software (Research Triangle International, NC, USA. Results: Decreases in the incidences of gastrointestinal perforation, gastrointestinal hemorrhage, and surgical procedures most specific to peptic ulcer disease were statistically significant over the study period [range of P value (two tailed = 0.000 - 0.00353; significant at P < 0.001 to < 0.01]. The incidence of H. pylori rose dramatically, peaking at an estimated 97,823 cases in 1998 [SE = 3155; 95% CI = 6,184]. Since that time it has decreased and then stabilized. Conclusions: The identification of H. pylori as the causative agent in the majority of peptic ulcer disease has revolutionized the understanding and management of the disease. Medical conditions and surgical procedures associated with end-stage peptic ulcer disease have significantly decreased according to analysis of selected index categories. Resident physician education objectives may need to be modified in light of these trends. Review Criteria: We reviewed patients with peptic ulcer disease. The database used was the Nationwide Inpatient Sample, 1993 to 2007. Message for the Clinic: Medical therapy has resulted in decreased morbidity from H. pylori infection as it

  9. Genomic organization of the human heparan sulfate-N-deacetylase/N-sulfotransferase gene: Exclusion from a causative role in the pathogenesis of Treacher Collins syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Gladwin, A.J.; Dixon, J.; Loftus, S.K.; Wasmuth, J.J.; Dixon, M.J. [Univ. of Manchester (United Kingdom)]|[Univ. of California, Irvine, CA (United States)


    Heparan sulfate-N-deacetylase/N-sulfotransferase (HSST) catalyzes both the N-deacetylation and the N-sulfation of heparan sulfate. Previous studies have resulted in the isolation of the human HSST gene from within the Treacher Collins syndrome locus (TCOF1) critical region on 5q. In the present study, the genomic organization of the HSST gene has been elucidated, and the 14 exons identified have been tested for TCOF1-specific mutations. As a result of these studies, mutations within the coding sequence and adjacent splice junctions of HSST can be excluded from a causative role in the pathogenesis of Treacher Collins syndrome. 13 refs., 1 fig., 2 tabs.

  10. Non-invasive evaluation of culprit lesions by PET imaging: shifting the clinical paradigm away from resultant anatomy toward causative physiology. (United States)

    Caobelli, Federico; Bengel, Frank M


    Although coronary angiography is the gold standard for assessing coronary artery disease (CAD), there is at best a weak correlation between degree of stenosis and the risk of developing cardiac events. Plaque rupture is the most common type of plaque complication, accounting for about 70% of fatal acute myocardial infarctions or sudden coronary deaths. Recently, the feasibility of (18)F-fluoride PET/CT in the evaluation of atherosclerotic lesions was assessed. Radionuclide techniques allow non-invasive biologic assessment of atherosclerotic plaques. This may help to further shift the clinical paradigm in coronary disease away from anatomy toward causative physiology and biology.

  11. DJ-1, an oncogene and causative gene for familial Parkinson's disease, is essential for SV40 transformation in mouse fibroblasts through up-regulation of c-Myc


    Kim, Yun Chul; Kitaura, Hirotake; Iguchi-Ariga, Sanae M. M.; Ariga, Hiroyoshi


    Simian virus 40 (SV40) is a tumor virus and its early gene product large T-antigen (LT) is responsible for the transforming activity of SV40. Parkinson's disease causative gene DJ-1 is also a ras-dependent oncogene, but the mechanism of its oncogene function is still not known. In this study, we found that there were no transformed foci when fibroblasts from DJ-1-knockout mice were transfected with LT. We also found that DJ-1 directly bound to LT and that the expression level of c-Myc in tran...

  12. Sensitivities of major causative organisms isolated from patients with acute uncomplicated cystitis against various antibacterial agents: results of subanalysis based on the presence of menopause. (United States)

    Matsumoto, Tetsuro; Hamasuna, Ryoichi; Ishikawa, Kiyohito; Takahashi, Satoshi; Yasuda, Mitsuru; Hayami, Hiroshi; Tanaka, Kazushi; Muratani, Tetsuro; Monden, Koichi; Arakawa, Soichi; Yamamoto, Shingo


    We investigated whether the presence of menopause influenced the species and distribution of causative bacteria isolated from patients with acute uncomplicated cystitis (the most common urinary tract infection), and we also investigated the sensitivity of the isolated species to antibacterial agents. Using multivariate analysis, we also investigated risk factors for infection with quinolone-resistant Escherichia coli, because its frequency has increased and it is now a clinical problem in Japan. Six hundred and thirty-four strains were isolated from 489 premenopausal patients (mean age 32.3 ± 10.1 years). Major causative bacteria detected were Escherichia coli (65.0 %), Enterococcus faecalis (12.0 %), Streptococcus agalactiae (5.5 %), and Klebsiella pneumoniae (1.6 %). From 501 postmenopausal patients (mean age 68.7 ± 10.29 years), 657 strains were isolated, and the major causative bacteria detected were E. coli (61.5 %), E. faecalis (13.7 %), K. pneumoniae (5.2 %), and S. agalactiae (4.0 %). The sensitivities to fluoroquinolones (FQs) and cephems of E. coli isolated from premenopausal patients were both ≥90 %, while the sensitivities to FQs of E. coli isolated from postmenopausal patients were about 5 % lower. In regard to infection with quinolone-resistant E. coli (minimal inhibitory concentration of levofloxacin [LVFX] ≥4 μg/mL), significant risk factors were observed in patients with more than two episodes of cystitis within a year (p = 0.0002), patients to whom antibacterial agents were used previously for this episode of cystitis (p = 0.0175), and patients who had a history of FQ administration within 1 month. Although the species and distribution of causative bacteria of acute uncomplicated cystitis were the same regardless of the presence of menopause, the sensitivities to FQs of E. coli detected in postmenopausal patients were significantly lower than those in the premenopausal women. The major risk factors for infection with quinolone-resistant E

  13. Small Duplication of HPRT 1 Gene May Be Causative For Lesh-Nyhan Disease in Iranian Patients

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    Full Text Available How to Cite This Article: Boroujerdi R, Shariati M, Naddafnia H, Rezaei H. Small Duplication of HPRT 1 Gene May Be Causative For Lesh-Nyhan Disease in Iranian Patients. Iran J Child Neurol. 2015 Winter;9(1:103-106.AbstractDeficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT is a rare inborn error of purine metabolism and is characterized by uric acid overproduction along with a variety of neurological manifestations that depend on a degree of the enzymatic deficiency. Inheritance of HPRT deficiency is X-linked recessive; thus, males are generally more affected and heterozygous females are carriers (usually asymptomatic. Human HPRT is encoded by a single structural gene on the long arm of the X chromosome at Xq26. More than 300 mutations in the HPRT1 gene have been detected. Diagnosis can be based on clinical and biochemical findings as well as enzymatic and molecular testing. Molecular diagnosis is the best way as it allows for faster and more accurate carrier and prenatal diagnosis. In this report, a new small duplication in the HPRT1 gene was found by sequencing, which has yet to be reported.References Fu R, Jinnah HA. Genotype-Phenotype Correlations in Lesch-Nyhan Disease Moving Beyond The Gene. Journal of Biological Chemistry. 2012; 287(5:2997- 3008.Fontenelle LJ, Henderson JF. An enzymatic basis for the inability of erythrocytes to synthesize purine ribonucleotides de novo. Biochim Biophys Acta. 1969 Feb 18; 177(1:175-6. PubMed PMID: 5781193.Kelley WN, Wyngaardcn JB. Clinical syndromes associated with hypoxanthine guanine Phosphoribosyl transferase deficiency. In: J. B. Stanbury, J. B. Wyngaarden, D. S. Frederickson, J. L. Goldstein, M. S. Brown, editors. The Metabolic Basis of Inherited Disease. 5 ed. New York: McGraw Hill; 1983. p. 1115-43.Lesch M, Nyhan WL. A Familial Disorder of Uric Acid Metabolism and Central Nervous System Function. Am J Med. 1964 Apr; 36:561-70. PubMed PMID: 14142409.Christie R, Bay C, Kaufman IA

  14. Culture Positivity of CVCs Used for TPN: Investigation of an Association with Catheter-Related Infection and Comparison of Causative Organisms between ICU and Non-ICU CVCs

    Directory of Open Access Journals (Sweden)

    Criona Walshe


    Full Text Available A relationship between central venous catheter (CVC tip colonisation and catheter-related blood-stream infection (CRBSI has been suggested. We examined culture positivity of CVC tips (colonised and infected CVCs in a total parenteral nutrition (TPN population. Our aims were to define the relationship between culture positivity and CRBSI, and to compare causative organisms between culture positive and CRBSI CVCS, and between ward and ICU CVCs. All patients receiving TPN via non-tunnelled CVCs during the study (1997–2009 were included. All CVC tips were analysed. Data were collated contemporaneously. A TPN audit committee determined whether CVC tip culture positivity reflected colonisation/CRBSI using CDC criteria. 1,392 patients received TPN via 2,565 CVCs over 15,397 CVC days. 25.4% of CVCs tips were culture positive, of these 32% developed CRBSI. There was a nonsignificant trend of higher Gram negative Bacilli isolation in ICU CVCs (=0.1, ward CVCs were associated with higher rates of staphylococcal isolation (=0.01. A similar pattern of organisms were cultured from CRBSI and culture positive CVCs. The consistent relationship between CRBSI and culture positive CVCs, and similar pattern of causative organisms further supports an aetiological relationship between culture positive CVC tips and CRBSI, supporting the contention that CVC culture-positivity may be a useful surrogate marker for CRBSI rates.

  15. Causative get-constructions in the dialogued passages in F. Scott Fitzgerald’s novels The Beautiful and Damned and Tender Is the Night as gender-conditioned structures

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    Gołąbek Rafał


    Full Text Available It goes without saying that in modern sociolinguistics there is a consensus with regard to the fact that the language of males and females differs. The initial sections of the article briefly address the peculiarities of gendered speech as to provide a theoretical background for checking whether the causative get is used similarly or differently by men and women in the two of F. Scott Fitzgerald’s novels: The Beautiful and Damned and Tender Is the Night. The basic expectation formed is that the motifs for triggering the use of causative get are of social rather than structural nature. Before the analysis is carried out, the group of the English periphrastic causatives are sketchily characterized. Generally, what has been found is that there is a clear, socially-motivated pattern of how F. Scott Fitzgerald uses the causative get in the dialogued occurrences in his two novels. Get is a characteristic of men’s talk, but it is also the expected form while female characters address male ones - hence the verb is labelled as “masculine” get. Moreover, it has been discovered that there does not seem to be any particular pattern in either the speaker’s mood or the speaker’s attitude expressed that would trigger the use of the causative verb in question. Yet, what seems to be a well-defined tendency, when it comes to the speaker-hearer power relation, is that the speaker usually assumes a more superior position than the hearer when he or she uses the causative verb. The superiority in most cases is strongly associated with masculinity. Hence, what is postulated is that the causative get is labelled not only as “masculine" but also as “superior”.

  16. Translation Strategies of Causation Expressions Seen in "Analects of Confucius" Translated by James Legge%从理雅各英译《论语》看使役概念的翻译策略

    Institute of Scientific and Technical Information of China (English)

    吕芳; 申霞


    认知语言学认为,使役概念表达是指人们对客观世界中典型使役事件的临摹或概念化。不同的语言学家对其有不同的理解,但大致将其分为词汇使役和句型使役。理雅各英译本《论语》中,采用多种翻译策略,如词汇使役、被动句式,位移一使役句式,双及物句式等来丰富使役表达的多样性。%Causation expression is human being's imitation and generalization of typological causation event in the real world from the perspective of cognitive linguistics. But different linguistics have different ideas about it, which generally is divided into lexi- cal causative and periphrastic causative. The thesis borrows previous research results to introduce causation into Analects of Confu- cius which was translated by James Legg. Then readers can see adept translation strategies of James. By the way, this research is also expected to shed great lights on C-E translation and also provides enlightenment to tbreign language teaching.

  17. The reliability of serogroup determination in the detection of Escherichia coli as a causative agent of sporadic and epidemic occurrence of enterocolitis

    Directory of Open Access Journals (Sweden)

    Stojanović Valentina


    Full Text Available The purpose of this study was to determine the presence of virulence factors (heat-labile, heat-stable enterotoxin, verotoxin, invasiveness, localized, aggregative and diffuse adherence among E. coli strains isolated from sporadic cases and outbreaks of enterocolitis, which belonged to serogroups characteristic for enteropathogenic E. coli. Serogroup was determined in 57.2% of 622 strains isolated from sporadic cases, and among them virulence factors were detected in 23.6%. Serogroup was also determined in 73.3% of 90 outbreaks isolates tested and virulence factors were detected in 97% of them. The detection rate of virulence factors rarely exceeded 50% among strains belonging to any of serogroup that was determined. The obtained data suggested that the identification of E. coli as a causative agent of enterocolitis by serogroup determination was a reliable method in outbreaks, but not in sporadic cases of this disease.

  18. Truncation of the MSH2 C-terminal 60 amino acids disrupts effective DNA mismatch repair and is causative for Lynch syndrome. (United States)

    Wielders, Eva; Delzenne-Goette, Elly; Dekker, Rob; van der Valk, Martin; Te Riele, Hein


    Missense variants of DNA mismatch repair (MMR) genes pose a problem in clinical genetics as long as they cannot unambiguously be assigned as the cause of Lynch syndrome (LS). To study such variants of uncertain clinical significance, we have developed a functional assay based on direct measurement of MMR activity in mouse embryonic stem cells expressing mutant protein from the endogenous alleles. We have applied this protocol to a specific truncation mutant of MSH2 that removes 60 C-terminal amino acids and has been found in suspected LS families. We show that the stability of the MSH2/MSH6 heterodimer is severely perturbed, causing attenuated MMR in in vitro assays and cancer predisposition in mice. This mutation can therefore unambiguously be considered as deleterious and causative for LS.

  19. Nanobody conjugated PLGA nanoparticles for active targeting of African Trypanosomiasis. (United States)

    Arias, José L; Unciti-Broceta, Juan D; Maceira, José; Del Castillo, Teresa; Hernández-Quero, José; Magez, Stefan; Soriano, Miguel; García-Salcedo, José A


    Targeted delivery of therapeutics is an alternative approach for the selective treatment of infectious diseases. The surface of African trypanosomes, the causative agents of African trypanosomiasis, is covered by a surface coat consisting of a single variant surface glycoprotein, termed VSG. This coat is recycled by endocytosis at a very high speed, making the trypanosome surface an excellent target for the delivery of trypanocidal drugs. Here, we report the design of a drug nanocarrier based on poly ethylen glycol (PEG) covalently attached (PEGylated) to poly(D,L-lactide-co-glycolide acid) (PLGA) to generate PEGylated PLGA nanoparticles. This nanocarrier was coupled to a single domain heavy chain antibody fragment (nanobody) that specifically recognizes the surface of the protozoan pathogen Trypanosoma brucei. Nanoparticles were loaded with pentamidine, the first-line drug for T. b. gambiense acute infection. An in vitro effectiveness assay showed a 7-fold decrease in the half-inhibitory concentration (IC50) of the formulation relative to free drug. Furthermore, in vivo therapy using a murine model of African trypanosomiasis demonstrated that the formulation cured all infected mice at a 10-fold lower dose than the minimal full curative dose of free pentamidine and 60% of mice at a 100-fold lower dose. This nanocarrier has been designed with components approved for use in humans and loaded with a drug that is currently in use to treat the disease. Moreover, this flexible nanobody-based system can be adapted to load any compound, opening a range of new potential therapies with application to other diseases.

  20. Socioeconomic inequality in health in the British household panel: Tests of the social causation, health selection and the indirect selection hypothesis using dynamic fixed effects panel models. (United States)

    Foverskov, Else; Holm, Anders


    Despite social inequality in health being well documented, it is still debated which causal mechanism best explains the negative association between socioeconomic position (SEP) and health. This paper is concerned with testing the explanatory power of three widely proposed causal explanations for social inequality in health in adulthood: the social causation hypothesis (SEP determines health), the health selection hypothesis (health determines SEP) and the indirect selection hypothesis (no causal relationship). We employ dynamic data of respondents aged 30 to 60 from the last nine waves of the British Household Panel Survey. Household income and location on the Cambridge Scale is included as measures of different dimensions of SEP and health is measured as a latent factor score. The causal hypotheses are tested using a time-based Granger approach by estimating dynamic fixed effects panel regression models following the method suggested by Anderson and Hsiao. We propose using this method to estimate the associations over time since it allows one to control for all unobserved time-invariant factors and hence lower the chances of biased estimates due to unobserved heterogeneity. The results showed no proof of the social causation hypothesis over a one to five year period and limited support for the health selection hypothesis was seen only for men in relation to HH income. These findings were robust in multiple sensitivity analysis. We conclude that the indirect selection hypothesis may be the most important in explaining social inequality in health in adulthood, indicating that the well-known cross-sectional correlations between health and SEP in adulthood seem not to be driven by a causal relationship, but instead by dynamics and influences in place before the respondents turn 30 years old that affect both their health and SEP onwards. The conclusion is limited in that we do not consider the effect of specific diseases and causal relationships in adulthood may be

  1. Loop-mediated isothermal amplification as an emerging technology for detection of Yersinia ruckeri the causative agent of enteric red mouth disease in fish

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    Soliman Hatem


    Full Text Available Abstract Background Enteric Redmouth (ERM disease also known as Yersiniosis is a contagious disease affecting salmonids, mainly rainbow trout. The causative agent is the gram-negative bacterium Yersinia ruckeri. The disease can be diagnosed by isolation and identification of the causative agent, or detection of the Pathogen using fluorescent antibody tests, ELISA and PCR assays. These diagnostic methods are laborious, time consuming and need well trained personnel. Results A loop-mediated isothermal amplification (LAMP assay was developed and evaluated for detection of Y. ruckeri the etiological agent of enteric red mouth (ERM disease in salmonids. The assay was optimised to amplify the yruI/yruR gene, which encodes Y. ruckeri quorum sensing system, in the presence of a specific primer set and Bst DNA polymerase at an isothermal temperature of 63°C for one hour. Amplification products were detected by visual inspection, agarose gel electrophoresis and by real-time monitoring of turbidity resulted by formation of LAMP amplicons. Digestion with HphI restriction enzyme demonstrated that the amplified product was unique. The specificity of the assay was verified by the absence of amplification products when tested against related bacteria. The assay had 10-fold higher sensitivity compared with conventional PCR and successfully detected Y. ruckeri not only in pure bacterial culture but also in tissue homogenates of infected fish. Conclusion The ERM-LAMP assay represents a practical alternative to the microbiological approach for rapid, sensitive and specific detection of Y. ruckeri in fish farms. The assay is carried out in one hour and needs only a heating block or water bath as laboratory furniture. The advantages of the ERM-LAMP assay make it a promising tool for molecular detection of enteric red mouth disease in fish farms.

  2. Identification of trypanosomes in wild animals from Southern Cameroon using the polymerase chain reaction (PCR

    Directory of Open Access Journals (Sweden)

    Herder S.


    Full Text Available One possible explanation of the maintenance of many historical foci of sleeping sickness in Central Africa could be the existence of a wild animal reservoir. In this study, PCR was used to detect the different trypanosome species present in wild animal captured by hunters in the southern forest belt of Cameroon (Bipindi. Trypanosomes were also detected by a parasitological method (Quantitative buffy coat : QBC. Parasite could not be isolated in culture medium (Kit for in vitro isolation : KIVI. Specific primers of T. brucei s.l., T. congolense forest type, T. congolense savannah type, T. vivax, T. simiae and T. b. gambiense group 1 were used to identify parasites in the blood of 164 animals belonging to 24 different species including ungulates, rodents, pangolins, carnivores, reptiles and primates. Of the 24 studied species, eight were carrying T. b. gambiense group 1. Those parasites pathogenic to man were found in monkeys (Cercocebus torquatus and Cercopithecus nictitans, in ungulates (Cephalophus dorsalis and C. monticola, in carnivores (Nandinia binotata and Genetta servalina and in rodents (Cricetomys gambianus and Atherurus africanus. 13 species (54 % were carrying T. brucei s.l. identified as non-gambiense group 1.

  3. Development of multiplex serological assay for the detection of human African trypanosomiasis. (United States)

    Nzou, Samson Muuo; Fujii, Yoshito; Miura, Masashi; Mwau, Matilu; Mwangi, Anne Wanjiru; Itoh, Makoto; Salam, Md Abdus; Hamano, Shinjiro; Hirayama, Kenji; Kaneko, Satoshi


    Human African trypanosomiasis (HAT) is a disease caused by Kinetoplastid infection. Serological tests are useful for epidemiological surveillance. The aim of this study was to develop a multiplex serological assay for HAT to assess the diagnostic value of selected HAT antigens for sero-epidemiological surveillance. We cloned loci encoding eight antigens from Trypanosoma brucei gambiense, expressed the genes in bacterial systems, and purified the resulting proteins. Antigens were subjected to Luminex multiplex assays using sera from HAT and VL patients to assess the antigens' immunodiagnostic potential. Among T. b. gambiense antigens, the 64-kDa and 65-kDa invariant surface glycoproteins (ISGs) and flagellar calcium binding protein (FCaBP) had high sensitivity for sera from T. b. gambiense patients, yielding AUC values of 0.871, 0.737 and 0.858 respectively in receiver operating characteristics (ROC) analysis. The ISG64, ISG65, and FCaBP antigens were partially cross-reactive to sera from Trypanosoma brucei rhodesiense patients. The GM6 antigen was cross-reactive to sera from T. b. rhodesiense patients as well as to sera from VL patients. Furthermore, heterogeneous antibody responses to each individual HAT antigen were observed. Testing for multiple HAT antigens in the same panel allowed specific and sensitive detection. Our results demonstrate the utility of applying multiplex assays for development and evaluation of HAT antigens for use in sero-epidemiological surveillance.

  4. Polymerase chain reaction detection of Leishmania DNA in skin biopsy samples in Sri Lanka where the causative agent of cutaneous leishmaniasis is Leishmania donovani. (United States)

    Ranasinghe, Shalindra; Wickremasinghe, Renu; Hulangamuwa, Sanjeeva; Sirimanna, Ganga; Opathella, Nandimithra; Maingon, Rhaiza D C; Chandrasekharan, Vishvanath


    Leishmania donovani is the known causative agent of both cutaneous (CL) and visceral leishmaniasis in Sri Lanka. CL is considered to be under-reported partly due to relatively poor sensitivity and specificity of microscopic diagnosis. We compared robustness of three previously described polymerase chain reaction (PCR) based methods to detect Leishmania DNA in 38 punch biopsy samples from patients presented with suspected lesions in 2010. Both, Leishmania genus-specific JW11/JW12 KDNA and LITSR/L5.8S internal transcribed spacer (ITS)1 PCR assays detected 92% (35/38) of the samples whereas a KDNA assay specific forL. donovani (LdF/LdR) detected only 71% (27/38) of samples. All positive samples showed a L. donovani banding pattern upon HaeIII ITS1 PCR-restriction fragment length polymorphism analysis. PCR assay specificity was evaluated in samples containing Mycobacterium tuberculosis, Mycobacterium leprae, and human DNA, and there was no cross-amplification in JW11/JW12 and LITSR/L5.8S PCR assays. The LdF/LdR PCR assay did not amplify M. leprae or human DNA although 500 bp and 700 bp bands were observed in M. tuberculosis samples. In conclusion, it was successfully shown in this study that it is possible to diagnose Sri Lankan CL with high accuracy, to genus and species identification, using Leishmania DNA PCR assays.

  5. `DSF' theory on mechanism of gushing anomaly in oil and water wells before an earthquake. I. Observation of gushing and causative hypothesis (United States)

    Liu-qiao, Wang; Shan-yin, Li


    The gushing anomaly that occurs prior to an earthquake, a short-term abnormal phenomenon of common occurrence, is simply described here. It has been observed by an automatic recording float gauge that has continually operated for nine years at Wei-jiaquan No. 5 well in Miquan County of Xinjiang Province (XMW-5 well). During this period, four abnormal events have been recorded which show that the water level curve of the anomaly has a characteristic shape. By analysing the characteristic shape of the water level curve, we believed that an unknown rapidly varying stress field operated prior to an earthquake, thereby compressing the aquifer bed to cause an elastic deformation seepage-flow effect. Thus, a two-dimensional model of a radially unsteady seepage flow within a single aquifer bed, under variable tectonic stress, and with a rectangular pulse, was proposed. The abnormal water-level curve was then quantitatively synthesized on the basis of the above theory. The causative hypothesis (DSF) is based on the elastic deformation seepage-flow (DSF) theory.

  6. Bioaccumulation of stentorin, the probable causative agent for discolored (“purple”) eggs and ovaries in blue catfish (Ictalurus furcatus) from Eufaula Lake, Oklahoma, USA (United States)

    Gale, Robert W.; Papoulias, Diana M.; Schmitt, Christopher J.


    Observations of reddish to “purple” discolored eggs in the ovaries of adult female blue catfish (Ictalurus furcatus) from the northern arm of Eufaula Lake, a eutrophic multiuse impoundment in east-central Oklahoma, were first reported in 2006. Blue catfish eggs are normally cream to light yellow. Reports peaked in 2007–2008 and declined through 2009–2010; purple eggs have not been reported between 2010 and 2014. In the laboratory, all tissues and fluids of affected fish were strongly orange-red fluorescent under UV illumination, with the fluorescence most apparent in the lipid-rich ovaries and eggs. The causative agent was isolated chromatographically and confirmed by mass spectrometry as stentorin (1,3,4,6,8,10,11,13-octahydroxy-2,5-diisopropyl-phenanthro[1,10,9,8,o,p,q,r,a]perylene-7,14-dione), the fluorescent, lipophilic pigment associated with the photoreceptor protein of the ciliated protozoan Stentor coeruleus (Heterotrichea; Stentoridae). Larval medaka (Orizias latipes) readily consumed S. coeruleus in the laboratory and were observed to fluoresce in the same manner as the affected blue catfish. Potential deleterious effects of stentorin bioaccumulation remain to be determined, as do the geographic extent and the identities of other fluorescent compounds isolated from catfish eggs and ovaries.

  7. Anion inhibition studies of the α-carbonic anhydrase from the protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas disease. (United States)

    Pan, Peiwen; Vermelho, Alane Beatriz; Scozzafava, Andrea; Parkkila, Seppo; Capasso, Clemente; Supuran, Claudiu T


    The protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas disease, encodes an α-class carbonic anhydrase (CA, EC, TcCA, which was recently shown to be crucial for its life cycle. Thiols, a class of strong TcCA inhibitors, were also shown to block the growth of the pathogen in vitro. Here we report the inhibition of TcCA by inorganic and complex anions and other molecules interacting with zinc proteins, such as sulfamide, sulfamic acid, phenylboronic/arsonic acids. TcCA was inhibited in the low micromolar range by iodide, cyanate, thiocyanate, hydrogensulfide and trithiocarbonate (KIs in the range of 44-93 μM), but the best inhibitor was diethyldithiocarbamate (KI=5 μM). Sulfamide showed an inhibition constant of 120 μM, but sulfamic acid was much less effective (KI of 10.6 mM). The discovery of diethyldithiocarbamate as a low micromolar TcCA inhibitor may be useful to detect leads for developing anti-Trypanosoma agents with a diverse mechanism of action compared to clinically used drugs (benznidazole, nifurtimox) for which significant resistance emerged.

  8. Cloning, characterization, and sulfonamide and thiol inhibition studies of an α-carbonic anhydrase from Trypanosoma cruzi, the causative agent of Chagas disease. (United States)

    Pan, Peiwen; Vermelho, Alane Beatriz; Capaci Rodrigues, Giseli; Scozzafava, Andrea; Tolvanen, Martti E E; Parkkila, Seppo; Capasso, Clemente; Supuran, Claudiu T


    An α-carbonic anhydrase (CA, EC has been identified, cloned, and characterized from the unicellular protozoan Trypanosoma cruzi, the causative agent of Chagas disease. The enzyme (TcCA) has a very high catalytic activity for the CO2 hydration reaction, being similar kinetically to the human (h) isoform hCA II, although it is devoid of the His64 proton shuttle. A large number of aromatic/heterocyclic sulfonamides and some 5-mercapto-1,3,4-thiadiazoles were investigated as TcCA inhibitors. The aromatic sulfonamides were weak inhibitors (K(I) values of 192 nM to 84 μM), whereas some heterocyclic compounds inhibited the enzyme with K(I) values in the range 61.6-93.6 nM. The thiols were the most potent in vitro inhibitors (K(I) values of 21.1-79.0 nM), and some of them also inhibited the epimastigotes growth of two T. cruzi strains in vivo.

  9. Novel NR5A1 missense mutation in premature ovarian failure: detection in han chinese indicates causation in different ethnic groups.

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    Xue Jiao

    Full Text Available BACKGROUND: The etiology of most premature ovarian failure (POF cases is usually elusive. Although genetic causes clearly exist and a likely susceptible region of 8q22.3 has been discovered, no predominant explanation exists for POF. More recently, evidences have indicated that mutations in NR5A1 gene could be causative for POF. We therefore screened for mutations in the NR5A1 gene in a large cohort of Chinese women with non-syndromic POF. METHODS: Mutation screening of NR5A1 gene was performed in 400 Han Chinese women with well-defined 46,XX idiopathic non-syndromic POF and 400 controls. Subsequently, functional characterization of the novel mutation identified was evaluated in vitro. RESULTS: A novel heterozygous missense mutation [c.13T>G (p.Tyr5Asp] in NR5A1 was identified in 1 of 384 patients (0.26%. This mutation impaired transcriptional activation on Amh, Inhibin-a, Cyp11a1 and Cyp19a1 gene, as shown by transactivation assays. However, no dominant negative effect was observed, nor was there impact on protein expression and nuclear localization. CONCLUSIONS: This novel mutation p.Tyr5Asp, in a novel non-domain region, is presumed to result in haploinsufficiency. Irrespectively, perturbation in NR5A1 is not a common explanation for POF in Chinese.

  10. Variability in triactinomyxon production from Tubifex tubifex populations from the same mitochondrial DNA lineage infected with Myxobolus cerebralis, the causative agent of whirling disease in salmonids (United States)

    Rasmussen, C.; Zickovich, J.; Winton, J.R.; Kerans, B.L.


    Myxobolus cerebralis, the causative agent of whirling disease, infects both salmonid fish and an aquatic oligochaete, Tubifex tubifex. Although M. cerebralis has been detected in river drainages throughout the United States, disease severity among wild fish populations has been highly variable. Tubifex tubifex populations have been genetically characterized using sequences from the 16S mitochondrial DNA (mtDNA) gene, the 18S ribosomal RNA gene, the internal transcribed spacer region 1 (ITS1), and randomly amplified polymorphic DNA (RAPD). Our earlier work indicated that large differences in compatibility between the parasite and populations of T. tubifex may play a substantial role in the distribution of whirling disease and resulting mortality in different watersheds. In the present study, we examined 4 laboratory populations of T. tubifex belonging to 16S mtDNA lineage III and 1 population belonging to 16S mtDNA lineage I for triactinomyxon (TAM) production after infection with M. cerebralis myxospores. All 4 16S mtDNA lineage III populations produced TAMs, but statistically significant differences in TAM production were observed. Most individuals in the 16S mtDNA lineage III-infected populations produced TAMs. The 16S mtDNA lineage I population produced few TAMs. Further genetic characterization of the 16S mtDNA lineage III populations with RAPD markers indicated that populations producing similar levels of TAMs had more genetic similarity. ?? American Society of Parasitologists 2008.

  11. Soluble material secreted from Penicillium chrysogenum isolate exhibits antifungal activity against Cryphonectria parasitica- the causative agent of the American Chestnut Blight (United States)

    Florjanczyk, Aleksandr; Barnes, Rebecca; Kenney, Adam; Horzempa, Joseph


    The American chestnut (Castanea dentata) was once the dominant canopy tree along the eastern region of the United States. Cryphonectria parasitica, the causative agent of chestnut blight, was introduced from Asia in the early 1900's, and obliterated the chestnut population within 50 years. We sought to identify environmental microbes capable of producing factors that were fungicidal or inhibited growth of C. parasitica in the hopes developing a biological control of chestnut blight. We isolated a filamentous fungus that significantly inhibited the growth of C. parasitica upon co-cultivation. Extracellular fractions of this fungal isolate prevented C. parasitica growth, indicating that a potential fungicide was produced by the novel isolate. Sequence analysis of 18S rRNA identified this inhibitory fungus as Penicillium chrysogenum. Furthermore, these extracellular fractions were tested as treatments for blight in vivo using chestnut saplings. Scarred saplings that were treated with the P. chrysogenum extracellular fractions healed subjectively better than those without treatment when inoculated with C. parasitica. These data suggest that material secreted by P. chrysogenum could be used as a treatment for the American chestnut blight. This work may assist the reclamation of the American chestnut in association with breeding programs and blight attenuation. Specifically, treatment of small groves under the right conditions may allow them to remain blight free. Future work will explore the mechanism of action and specific target of the extracellular fraction. PMID:27274909

  12. Clinical features, diagnosis, and treatment of human African trypanosomiasis (sleeping sickness). (United States)

    Kennedy, Peter Ge


    Human African trypanosomiasis, or sleeping sickness, is caused by infection with parasites of the genus Trypanosoma, transmitted by the tsetse fly. The disease has two forms, Trypanosoma brucei (T b) rhodesiense and T b gambiense; and is almost always fatal if untreated. Despite a recent reduction in the number of reported cases, patients with African trypanosomiasis continue to present major challenges to clinicians. Because treatment for CNS-stage disease can be very toxic, diagnostic staging to distinguish early-stage from late-stage disease when the CNS in invaded is crucial but remains problematic. Melarsoprol is the only available treatment for late-stage T b rhodesiense infection, but can be lethal to 5% of patients owing to post-treatment reactive encephalopathy. Eflornithine combined with nifurtimox is the first-line treatment for late-stage T b gambiense. New drugs are in the pipeline for treatment of CNS human African trypanosomiasis, giving rise to cautious optimism.

  13. Mutations causative of familial hypercholesterolaemia

    DEFF Research Database (Denmark)

    Benn, Marianne; Watts, Gerald F; Tybjærg-Hansen, Anne


    AIMS: Ideally, familial hypercholesterolaemia (FH) is diagnosed by testing for mutations that decrease the catabolism of low-density lipoprotein (LDL) cholesterol; however, genetic testing is not universally available. The aim of the present study was to assess the frequency and predictors of FH...... causing mutations in 98 098 participants from the general population, the Copenhagen General Population Study. METHODS AND RESULTS: We genotyped for LDLR[W23X;W66G;W556S] and APOB[R3500Q] accounting for 38.7% of pathogenic FH mutations in Copenhagen. Clinical FH assessment excluded mutation information....... The prevalence of the four FH mutations was 0.18% (1:565), suggesting a total prevalence of FH mutations of 0.46% (1:217). Using the Dutch Lipid Clinic Network (DLCN) criteria, odds ratios for an FH mutation were 439 (95% CI: 170-1 138) for definite FH, 90 (53-152) for probable FH, and 18 (13-25) for possible FH...

  14. Survey on Trypanosoma spp. infection of dogs in Gabon and its epidemiological implications for sleeping sickness. (United States)

    Watier-Grillot, S; Herder, S; Marié, J-L; Bourry, O; Cuny, G; Davoust, B


    This survey screened native dogs (Canis familiaris) in Gabon (Africa) for trypanosome infection. A total of 376 apparently healthy dogs, divided into two populations, were examined. The first group included 252 semi-domesticated dogs inhabiting 16 villages of the Ogooué-Ivindo Province, a rural inland area in northeast Gabon, and the second group 124 dogs belonging to protection companies or families from Libreville (n = 113) and Port-Gentil (n = 11), in the coastal area of Gabon. Both study areas include active or former foci of sleeping sickness in Gabon. Molecular testing (polymerase chain reaction) was performed on blood samples from dogs in both groups. All dogs were negative for T. congolense ("savanna type" and "forest type"). Eighteen dogs (4.7%), however, tested positive for T. brucei s.l.: 3% (8/252) were from the Ogooué-Ivindo Province, and 8% (10/124) from the coastal area. These animals may be potential reservoirs of the parasite T. brucei gambiense, responsible for human African trypanosomiasis. This hypothesis, as well as the role of the dog as a sentinel of human infection by T. brucei gambiense, should be investigated in further studies.

  15. Growth of Ehrlichia canis, the causative agent of canine monocytic ehrlichiosis, in vector and non-vector ixodid tick cell lines. (United States)

    Ferrolho, Joana; Simpson, Jennifer; Hawes, Philippa; Zweygarth, Erich; Bell-Sakyi, Lesley


    Canine monocytic ehrlichiosis is caused by Ehrlichia canis, a small gram-negative coccoid bacterium that infects circulating monocytes. The disease is transmitted by the brown dog tick Rhipicephalus sanguineus s.l. and is acknowledged as an important infectious disease of dogs and other members of the family Canidae worldwide. E. canis is routinely cultured in vitro in the canine monocyte-macrophage cell line DH82 and in non-vector Ixodes scapularis tick cell lines, but not in cells derived from its natural vector. Here we report infection and limited propagation of E. canis in the tick cell line RSE8 derived from the vector R. sanguineus s.l., and successful propagation through six passages in a cell line derived from the experimental vector Dermacentor variabilis. In addition, using bacteria semi-purified from I. scapularis cells we attempted to infect a panel of cell lines derived from non-vector species of the tick genera Amblyomma, Dermacentor, Hyalomma, Ixodes and Rhipicephalus with E. canis and, for comparison, the closely-related Ehrlichia ruminantium, causative agent of heartwater in ruminants. Amblyomma and non-vector Dermacentor spp. cell lines appeared refractory to infection with E. canis but supported growth of E. ruminantium, while some, but not all, cell lines derived from Hyalomma, Ixodes and Rhipicephalus spp. ticks supported growth of both pathogens. We also illustrated and compared the ultrastructural morphology of E. canis in DH82, RSE8 and I. scapularis IDE8 cells. This study confirms that E. canis, like E. ruminantium, is able to grow not only in cell lines derived from natural and experimental tick vectors but also in a wide range of other cell lines derived from tick species not known to transmit this pathogen.

  16. Development and Evaluation of a Molecular Diagnostic Method for Rapid Detection of Histoplasma capsulatum var. farciminosum, the Causative Agent of Epizootic Lymphangitis, in Equine Clinical Samples. (United States)

    Scantlebury, C E; Pinchbeck, G L; Loughnane, P; Aklilu, N; Ashine, T; Stringer, A P; Gordon, L; Marshall, M; Christley, R M; McCarthy, A J


    Histoplasma capsulatum var. farciminosum, the causative agent of epizootic lymphangitis (EZL), is endemic in parts of Africa. Diagnosis based on clinical signs and microscopy lacks specificity and is a barrier to further understanding this neglected disease. Here, a nested PCR method targeting the internal transcribed spacer (ITS) region of the rRNA operon was validated for application to equine clinical samples. Twenty-nine horses with signs of EZL from different climatic regions of Ethiopia were clinically examined. Blood samples and aspirates of pus from cutaneous nodules were taken, along with blood from a further 20 horses with no cutaneous EZL lesions. Among the 29 horses with suspected cases of EZL, H. capsulatum var. farciminosum was confirmed by extraction of DNA from pus and blood samples from 25 and 17 horses, respectively. Positive PCR results were also obtained with heat-inactivated pus (24 horses) and blood (23 horses) spotted onto Whatman FTA cards. Two positive results were obtained among blood samples from 20 horses that did not exhibit clinical signs of EZL. These are the first reports of the direct detection of H. capsulatum var. farciminosum in equine blood and at high frequency among horses exhibiting cutaneous lesions. The nested PCR outperformed conventional microscopic diagnosis, as characteristic yeast cells could be observed only in 14 pus samples. The presence of H. capsulatum var. farciminosum DNA was confirmed by sequencing the cloned PCR products, and while alignment of the ITS amplicons showed very little sequence variation, there was preliminary single nucleotide polymorphism-based evidence for the existence of two subgroups of H. capsulatum var. farciminosum This molecular diagnostic method now permits investigation of the epidemiology of EZL.

  17. On the multiscale nature of soil moisture-temperature couplings: the role of seasonality, causation and non-linear feedbacks in land-atmosphere interactions (Invited) (United States)

    Molini, A.; Casagrande, E.; Mueller, B.


    Land-Atmosphere (L-A) interactions, their strength and directionality, are one of the main sources of uncertainty in current climate modeling, with strong implications on the accurate assessment of future climate variability and climate change impacts. Beside from the scarcity of direct observations, major uncertainties derive from the inherent complexity and nonlinearity of these interactions, and from their multi-scale character. Statistical analysis of L-A couplings is traditionally based on linear correlation methods and metrics. However, these approaches are not designed to detect causal connections or non-linear couplings and they poorly perform in presence of non-stationarities. Additionally these methods assess L-A couplings essentially in the time domain, despite the fact that L-A dynamical drivers can act simultaneously over a wide range of different space and time scales. This talk explores the multi-scale nature of L-A interactions, through the example of soil moisture-temperature couplings and soil-moisture memory effects. In several regions of the world, soil moisture can have a dampening effect on temperature due to evaporative cooling. By using spectral decomposition techniques and both newly developed satellite based products and re-analysis, we analyze the contribution of different time scales to the build-up of global soil moisture-temperature coupling hot spots, addressing at the same time the role of seasonality, causation and non-linear feedbacks in land-atmosphere interactions. Finally we focus on the role of fine (sub-monthly) time scales and their interplay with the seasonal scales.

  18. Social Health Insurance-Based Simultaneous Screening for 154 Mutations in 19 Deafness Genes Efficiently Identified Causative Mutations in Japanese Hearing Loss Patients. (United States)

    Mori, Kentaro; Moteki, Hideaki; Miyagawa, Maiko; Nishio, Shin-Ya; Usami, Shin-Ichi


    Sensorineural hearing loss is one of the most common neurosensory disorders in humans. The incidence of SNHL is estimated to be 1 in 500-1000 newborns. In more than half of these patients, the hearing loss is associated with genetic causes. In Japan, genetic testing for the patients with SNHL using the Invader assay to screen for 46 mutations in 13 deafness genes was approved by the Ministry of Health, Labour and Welfare for inclusion in social health insurance coverage in 2012. Furthermore, from August 2015, this genetic testing has been expanded to screen for 154 mutations in 19 deafness genes using targeted genomic enrichment with massively parallel DNA sequencing combined with the Invader assay and TaqMan genotyping. For this study we analyzed 717 unrelated Japanese hearing loss patients. The total allele frequency of 154 mutations in 19 deafness genes was 32.64% (468/1434) and the total numbers of cases associated with at least one mutation was 44.07% (316/717). Among these, we were able to diagnose 212 (30%) patients, indicating that the present screening could efficiently identify causative mutations in hearing loss patients. It is noteworthy that 27 patients (3.8%) had coexistent multiple mutations in different genes. Five of these 27 patients (0.7%, 5/717 overall) were diagnosed with genetic hearing loss affected by concomitant with responsible mutations in more than two different genes. For patients identified with multiple mutations in different genes, it is necessary to consider that several genes might have an impact on their phenotypes.

  19. Testing of four Leishmania vaccine candidates in a mouse model of infection with Leishmania (Viannia) braziliensis, the main causative agent of cutaneous leishmaniasis in the New World. (United States)

    Salay, G; Dorta, M L; Santos, N M; Mortara, R A; Brodskyn, C; Oliveira, C I; Barbiéri, C L; Rodrigues, M M


    We evaluated whether four recombinant antigens previously used for vaccination against experimental infection with Leishmania (Leishmania) major could also induce protective immunity against a challenge with Leishmania (Viannia) braziliensis, the species responsible for 90% of the 28,712 annual cases of cutaneous and mucocutaneous leishmaniasis recorded in Brazil during the year of 2004. Initially, we isolated the homolog genes encoding four L. (V.) braziliensis antigens: (i) homologue of receptor for activated C kinase, (ii) thiol-specific antioxidant, (iii) Leishmania elongation and initiation factor, and (iv) L. (L.) major stress-inducible protein 1. At the deduced amino acid level, all four open reading frames had a high degree of identity with the previously described genes of L. (L.) major being expressed on promastigotes and amastigotes of L. (V.) braziliensis. These genes were inserted into the vector pcDNA3 or expressed as bacterial recombinant proteins. After immunization with recombinant plasmids or proteins, BALB/c mice generated specific antibody or cell-mediated immune responses (gamma interferon production). After an intradermal challenge with L. (V.) braziliensis infective promastigotes, no significant reduction on the lesions was detected. We conclude that the protective immunity afforded by these four vaccine candidates against experimental cutaneous leishmaniasis caused by L. (L.) major could not be reproduced against a challenge with L. (V.) braziliensis. Although negative, we consider our results important since they suggest that studies aimed at the development of an effective vaccine against L. (V.) braziliensis, the main causative agent of cutaneous leishmaniasis in the New World, should be redirected toward distinct antigens or different vaccination strategies.

  20. Toxicology-based cancer causation analysis of CoCr-containing hip implants: a quantitative assessment of genotoxicity and tumorigenicity studies. (United States)

    Christian, Whitney V; Oliver, Lindsay D; Paustenbach, Dennis J; Kreider, Marisa L; Finley, Brent L


    In this paper, quantitative methods were used to evaluate the weight of evidence regarding a causative relationship between cobalt-chromium (CoCr)-containing hip implants and increased cancer risk. We reviewed approximately 80 published papers and identified no-observed-adverse-effect level (NOAEL) and/or lowest-observed-adverse-effect level (LOAEL) values for specific endpoints of interest: genotoxic effects from in vitro studies with human cell lines as well as genotoxicity and tumor formation in animal bioassays. Test articles included Co particles and ions, Cr particles and ions, and CoCr alloy particles as well as CoCr alloy implants. The NOAEL/LOAEL values were compared with body burdens of Co/Cr particles and ions we calculated to exist in systemic tissues of hip implant patients under normal and excessive wear conditions. We found that approximately 40 tumor bioassays have been conducted with CoCr alloy implants or Co/Cr particles and ions at levels hundreds to thousands of times higher than those present in hip implant patients, and none reported a statistically significant increased incidence of systemic tumors. Results from in vitro and in vivo genotoxicity assays, which are relatively less informative owing to false positives and other factors, also indicated that DNA effects would be highly unlikely to occur as a result of wear debris from a CoCr implant. Hence, the toxicological weight of evidence suggests that CoCr-containing hip implants are unlikely to be associated with an increased risk of systemic cancers, which is consistent with published and ongoing cancer epidemiology studies involving patients with CoCr hip implants.

  1. Candidate gene sequencing of SLC11A2 and TMPRSS6 in a family with severe anaemia: common SNPs, rare haplotypes, no causative mutation.

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    Anita Kloss-Brandstätter

    Full Text Available BACKGROUND: Iron-refractory iron deficiency anaemia (IRIDA is a rare disorder which was linked to mutations in two genes (SLC11A2 and TMPRSS6. Common polymorphisms within these genes were associated with serum iron levels. We identified a family of Serbian origin with asymptomatic non-consanguineous parents with three of four children presenting with IRIDA not responding to oral but to intravenous iron supplementation. After excluding all known causes responsible for iron deficiency anaemia we searched for mutations in SLC11A2 and TMPRSS6 that could explain the severe anaemia in these children. METHODOLOGY/RESULTS: We sequenced the exons and exon-intron boundaries of SLC11A2 and TMPRSS6 in all six family members. Thereby, we found seven known and fairly common SNPs, but no new mutation. We then genotyped these seven SNPs in the population-based SAPHIR study (n = 1,726 and performed genetic association analysis on iron and ferritin levels. Only two SNPs, which were top-hits from recent GWAS on iron and ferritin, exhibited an effect on iron and ferritin levels in SAPHIR. Six SAPHIR participants carrying the same TMPRSS6 genotypes and haplotype-pairs as one anaemic son showed lower ferritin and iron levels than the average. One individual exhibiting the joint SLC11A2/TMPRSS6 profile of the anaemic son had iron and ferritin levels lying below the 5(th percentile of the population's iron and ferritin level distribution. We then checked the genotype constellations in the Nijmegen Biomedical Study (n = 1,832, but the profile of the anaemic son did not occur in this population. CONCLUSIONS: We cannot exclude a gene-gene interaction between SLC11A2 and TMPRSS6, but we can also not confirm it. As in this case candidate gene sequencing did not reveal causative rare mutations, the samples will be subjected to whole exome sequencing.

  2. A three-step programmed method for the identification of causative gene mutations of maturity onset diabetes of the young (MODY). (United States)

    Li, Qian; Cao, Xi; Qiu, Hai-Yan; Lu, Jing; Gao, Rui; Liu, Chao; Yuan, Ming-Xia; Yang, Guang-Ran; Yang, Jin-Kui


    To establish a three-step programmed method to find gene mutations related to maturity onset diabetes of the young (MODY). Target region capture and next-generation sequencing (NGS) were performed using customized oligonucleotide probes designed to capture suspected genes for MODY in 11 probands with clinically diagnosed MODY. The suspected associations of certain genes with MODY were then confirmed by Sanger sequencing in the probands and their family members. Finally, to validate variants of one of the genes of interest (glucokinase, GCK) as pathogenic mutations, protein function editing by the variant genes was assessed. In the target region capture and NGS phase, a total of nine variants of seven genes (GCK, WFS1, SLC19A2, SH2B1, SERPINB4, RFX6, and GATA6) were identified in eight probands. Two heterozygous GCK mutations located on the same allele (p.Leu77Arg and p.Val101Met) were identified in a MODY family. Sanger sequencing was used to confirm the variants identified by NGS to be present in probands and their diabetic family members, but not in non-diabetic family members. Finally, enzyme kinetic and thermal stability analyses revealed that the p.Leu77Arg mutation or the p.Leu77Arg mutation in combination with the p.Val101Met mutation inactivates GCK function and stability, while mutation of p.Val101Met alone does not. The p.Leu77Arg but not p.Val101Met GCK mutation is therefore considered a pathogenic mutation associated with MODY. Genetic screening coupled with gene-editing protein function testing is an effective and reliable method by which causative gene mutations of MODY can be identified.

  3. Potent Inhibition of Pseudogymnoascus destructans, the Causative Agent of White-Nose Syndrome in Bats, by Cold-Pressed, Terpeneless, Valencia Orange Oil.

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    Nicholas Boire

    Full Text Available The causative agent of White-nose Syndrome (WNS, Pseudogymnoascus destructans, has been shown to be fatal to several species of bats in North America. To date, no compounds or chemical control measures have been developed which eliminates the growth of the fungus in the environment or in affected animals. In the current study, we evaluated the activity of cold-pressed, terpeneless orange oil (CPT against multiple isolates of P. destructans in vitro. For all assays, a modified Kirby-Bauer disk diffusion assay was used. Standardized spore suspensions were prepared, adjusted to a specific optical density, and used to plate fungal lawns. Plates were incubated at either 15°C or 4°C for up to 6 months and checked at regular intervals for growth. Once controls had grown, zones of inhibition were measured (mm on test plates and compared to those obtained using current antifungal drugs. All P. destructans isolates were completely inhibited by 100% CPT (10 μL at 1 month of incubation regardless of temperature (4°C and 15°C. Complete inhibition persisted up to 6 months following a single exposure at this concentration. Of the standard antifungals, only amphotericin B demonstrated any activity, resulting in zone diameters ranging from 58 mm to 74 mm. CPT, at the highest concentration tested (100%, had no significant effect against a variety of other environmental organisms including various filamentous fungi, bacteria and aerobic actinomycetes. Given that CPT is relatively non-toxic, the possibility exists that the all-natural, mixture could be used as an environmental pre-treatment to eradicate P. destructans from bat habitats. Additional studies are needed to assess any undesirable effects of CPT on bat behavior and health and overall impacts on other members of the interconnected ecosystem(s.

  4. Testing of Four Leishmania Vaccine Candidates in a Mouse Model of Infection with Leishmania (Viannia) braziliensis, the Main Causative Agent of Cutaneous Leishmaniasis in the New World▿ (United States)

    Salay, G.; Dorta, M. L.; Santos, N. M.; Mortara, R. A.; Brodskyn, C.; Oliveira, C. I.; Barbiéri, C. L.; Rodrigues, M. M.


    We evaluated whether four recombinant antigens previously used for vaccination against experimental infection with Leishmania (Leishmania) major could also induce protective immunity against a challenge with Leishmania (Viannia) braziliensis, the species responsible for 90% of the 28,712 annual cases of cutaneous and mucocutaneous leishmaniasis recorded in Brazil during the year of 2004. Initially, we isolated the homolog genes encoding four L. (V.) braziliensis antigens: (i) homologue of receptor for activated C kinase, (ii) thiol-specific antioxidant, (iii) Leishmania elongation and initiation factor, and (iv) L. (L.) major stress-inducible protein 1. At the deduced amino acid level, all four open reading frames had a high degree of identity with the previously described genes of L. (L.) major being expressed on promastigotes and amastigotes of L. (V.) braziliensis. These genes were inserted into the vector pcDNA3 or expressed as bacterial recombinant proteins. After immunization with recombinant plasmids or proteins, BALB/c mice generated specific antibody or cell-mediated immune responses (gamma interferon production). After an intradermal challenge with L. (V.) braziliensis infective promastigotes, no significant reduction on the lesions was detected. We conclude that the protective immunity afforded by these four vaccine candidates against experimental cutaneous leishmaniasis caused by L. (L.) major could not be reproduced against a challenge with L. (V.) braziliensis. Although negative, we consider our results important since they suggest that studies aimed at the development of an effective vaccine against L. (V.) braziliensis, the main causative agent of cutaneous leishmaniasis in the New World, should be redirected toward distinct antigens or different vaccination strategies. PMID:17626159

  5. 机械通气病人合并腹胀的诱发因素及干预现状%Causative factors and intervention status of mechanical ventilation patients complicated with abdominal distension

    Institute of Scientific and Technical Information of China (English)

    李平东; 曾小红; 郑则广


    It reviewed the causative factors of abdominal distension in patients accepting, mechanical ventilation, and mainly summarized the ventilator use, patients'own physical condition, application of antibiotics and nutritional support program,etc. And it summarized the interventions aiming at the causative factors.%综述了机械通气病人腹胀的诱发因素,主要总结了呼吸机使用本身、病人自身身体状况和抗生素的应用三方面的因素以及营养支持方案等,并针对诱发因素总结了干预措施.

  6. Theory and practice of non-determinism on identifying the causation in personal tort%人身侵权因果关系非决定论倾向与实践

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    The paper analyzes the philosophical and social basis of the non-determinism on identif-ying causation in personal tort .Under the impact on quantum mechanics , the causation in philosophy has changed from determinism to the non-determinism , and so does the causation in the science of law , which shows in the loss of a chance doctrine of medical tort in the field of personal tort and the doctrine of epi -demiology causality in environmental tort .However the non-determinism on identifying the causation is not suitable for all the cases , while determinism is still the mainstream in current jurisprudential research and law practice .%针对人身侵权领域出现的因果关系非决定倾向,分析了其哲学、科学基础。认为受量子力学影响,哲学上的因果关系经历了从决定论到非决定论的嬗变,法学上的因果关系亦因应了这种变化,在人身侵权领域的医疗侵权案件中出现了机会丧失理论,在环境侵权案件中出现了疫学因果关系理论。但因果关系非决定论并非在所有案件中一体适用,因果关系决定论仍然是目前法学研究和法律实践中的主流。

  7. West-African trypanosomiasis in a returned traveller from Ghana: an unusual cause of progressive neurological decline. (United States)

    Elliott, Ivo; Patel, Trupti; Shah, Jagrit; Venkatesan, Pradhib


    West-African trypanosomiasis caused by Trypanosoma brucei gambiense is a rare imported infection presenting with somnolence, lymphadenopathy and wide-ranging neurological symptoms. A 67-year-old Caucasian man presented with a 10-month history of cognitive deterioration, ataxic gait, somnolence and urinary incontinence. His symptoms had progressed more rapidly over the course of a month prior to admission. Serological testing confirmed a diagnosis of West-African trypanosomiasis. The patient was successfully treated with eflornithine and made a good recovery. West-African trypanosomiasis should be considered in the differential diagnosis of unexplained cognitive decline in those with a relevant travel history. If left untreated, the condition is universally fatal.

  8. Study of the Prevalence of Causative Bacterial&Protozoal Agents of in Stool Samples of 470 Gastroenteritis Patients Referring to the Nikoopour Clinic in Yazd,Iran

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    MR Sharifi


    Full Text Available Interoduction: Gasteroenteritis is one of the problems worth consideration all over the world. It is one of the important causes of mortality, especially in children < 5 years of age, in developing countries including Iran. The aim of this descriptive study was to determine the demographic conditions influencing the presence of causative bacteria and protozoa, followed by antibiograms of isolated bacteria from stool samples of patients with gasteroenteritis referring to Nikoopour Clinic in the city of Yazd, Iran from 1998 – 2001. Materials and method: A total of 470 samples were microbiologically examined by direct method, culture and then antibiogramed. In order to isolate the possible bacteria, differential and selected media were used. Also, wet – mount technique was applied for detection of protozoa. Results: Results revealed that 272 samples (57.9% were infected by pathogenic bacteria or protozoa. 138 (50.8% pathogenic specimens were from male patients and the remaining 134(49.3% were from female patients. Isolated species were: Enteropathogenic E.coli 117(43%, Shigella 51(18.8%, Salmonella.interetidis 25(9.2%, C.jejuni 16(5.9%, Giardia lambdia 51(18.8% and Amoebae spp 12(4.4%. The most commonly detected shigella species was dysenteriae, (74.5% while boydii with 2% was the least common type observed in the specimens. Except shigella, all the other bacteria were more common in males than female, but insignificant statistically. In order to determine the sensitivity and/or resistance of pathogenic bacteria, antibiogram test was performed using selected antibiotic disks such as Ampicillin, Nalidixic Acid, Ciprofloxacin, Gentamycin and Sulfamethaxazole. Conclusion: Results revealed that some patients were probably infected by pathogenic factors other than bacteria or protozoa. Since all viruses and parasites are almost resistant to antibiotics and on the other hand, administration of antibiotics may lead to resistance of bacterial agents

  9. Detection of causative allergens of cosmetic allergic contact dermatitis%化妆品变应性接触性皮炎变应原检测分析

    Institute of Scientific and Technical Information of China (English)

    蔡永莲; 刘润秋; 施辛; 张静; 黎平


    Objective To make a survey on common cosmetic allergens, and to provide epidemiological data and clinical evidence for cosmetic allergy. Methods Patch test was performed by using 49cosmetic allergens from a European cosmetic series and 5 Chinese standard screening allergens on 89patients with suspected cosmetic allergic contact dermatitis. Test results were determined according to the International Contact Dermatitis Research Group (ICDRG) recommendation. Results Of the 89 patients, 61(68.5%) showed positive reactions to one or more cosmetic allergens. The most common allergens were fragrances (33.7%), followed by preservatives (30.3%), para-phenylenediamine (25.8%) and amerchol L 101(10.1%). Conclusion Fragrances, preservatives, para-phenylenediamine and amerchol L 101 are dominant causative allergens in patients with cosmetic allergic contact dermatitis.%目的 调查化妆品变应原种类,为化妆品过敏提供流行病学资料和临床依据.方法 对89例门诊疑诊化妆品变应性接触性皮炎患者采用49种欧洲化妆品系列变应原及5种中国筛查系列化妆品变应原进行斑贴试验,按国际接触性皮炎研究组推荐标准判读结果.结果 89例患者中,61例对1种或1种以上化妆品变应原过敏,阳性反应率68.5%.其中阳性率较高的有香料33.7%,防腐剂30.3%,对苯二胺25.8%,阿莫醇10.1%.结论 香料、防腐剂、对苯二胺、阿莫醇等是化妆品变应性接触性皮炎患者的主要致敏原.


    Park, S; Chaudhari, A A; Pillai, S; Singh, S R; Willard, S T; Ryan, P L; Feugang, J M


    Pathogenic bacteria including Escherichia coli and Salmonella sp. are the major causative agents of endometritis and can cause infertility in livestock animals. Antibiotics are commonly used to terminate bacterial infections, but the development of bacterial antibiotic resistance is often encountered. Nanotechnology associated with silver nanoparticles has been highlighted as an alternative anti-bacterial agent, and pegylated silver-coated single-walled carbon nanotubes have high anti-bacterial effects and are non-toxic to human and murine cells in vitro. Here we verified whether a real-time bioluminescence monitoring system could be an alternative tool to assess anti-bacterial effects of nanotubes in a noninvasive approach. Escherichia coli and Salmonella sp. were transfected with plasmids containing constructs for luciferase enzyme (LuxCDABE) and substrate (luciferin) to create self-illuminating bioluminescent bacteria. Pathogens were grown in LB broth at 37°C, adjusted to 10(7) cfumL(-1), and placed in 96-well plates for treatments. Pegylated (pSWCNTs-Ag) and non-pegylated (SWCNTs-Ag) nanotubes were prepared and added to culture wells at various concentrations (31.25-125µgmL(-1)). The control group corresponded to bacteria without nanotubes (0µgmL(-1)). Anti-bacterial effects of nanotubes were determined every 10min until 1h, then every 30min up to 6h incubation through optical density (600nm) measurements and bioluminescence imaging (BLI) and quantification using an IVIS system. Optical density and BLI data were compared at each time-point using 2-way ANOVA, with PBioluminescence signals emitted by both bacteria stains appeared within 10min of incubation. Thereafter, control bacteria showed exponential growth that was detected as early as 25min post-incubation. Bioluminescence imaging revealed dose-dependent anti-bacterial activities of both pSWCNTs-Ag and SWCNTs-Ag on each E. coli and Salmonella sp. (P0.05); meanwhile, pSWCNTs-Ag nanotubes exhibited


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    Full Text Available BACKGROUND We all know asthma as a chronic inflammatory condition of allergic aetiology, so we tried to know factors responsible for development of persistent asthma in atopic patients who previously were intermittently symptomatic. METHOD We took 25 patients of persistent asthma as of recent origin (Criteria: need of regular preventive inhalational medications on regular basis since last 1–5 years and analysed their lifestyle of previous 5 years on 6 below mentioned points: 1. Change to sedentary lifestyle. 2. Weight gain. 3. Any form of mental stress. 4. Change in dietary factors. We took patients coming to our secondary referral hospital for continuous need of preventive inhalers, we took patients from middle age, i.e. from 30 to 35 years of age only of both sexes. RESULTS Out of 25 patient’s results for various factors were as follows: 1. Sedentary lifestyle: - Out of 25 patients, 20 developed need for regular medication use after their routine changed in such a way that most part of their job needed sedentary lifestyle and most of them do not pursue any regular exercise pattern. 2. Most of them gain weight in excess, after which they needed preventers on regular basis. 3. Interestingly many of them started using preventers on regular basis after a severe emotional stress of medium duration, as determined by use of hypnotics or antidepressant medication. In our study, we found that depression was a major risk factor for development of persistent symptoms in already intermittently symptomatic patients. 4. Interestingly majority of patients started needing preventers after they switched their diet from home-based low fat diet to hotel-based high fat diet, from regular frequent small meals to irregular large meals. CONCLUSION In conclusion we found that apart from allergic sensitisation, lifestyle factors are key causative factors in transformation from intermittent-to-persistent symptomatology in allergic-asthmatic patients, establishing

  12. 260例浅部真菌病及致病菌种分析%Aanlysis on 260 cases of superficial mycosis and its causative agents

    Institute of Scientific and Technical Information of China (English)

    米拉; 帕丽达·阿布利孜; 刘旭; 董潇阳; 哈德丽亚; 周珊


    Objective To investigate the etiologic agents of superficial mycosis in Urmuqi and its distribution.Methods Direct microscopic check and fungi cultivation were performed on illness hairs, scales, nail debris of suspected superficial mycosis patients in the Department of Dermatology of the First Affiliated Hospital of Xinjiang Medical University during February 2004 to August 2010. For culture positive samples, bassed on the morphologic identification, the sequences of ITS region of ribosomal DNA (rDNA) were identified. The results were analysed by SPSS 17.0 statistical software. Results There were 260 cases showed positive results in both direct checking and cultivation. The positive rate of Tinea capitis culture was the highest (33. 1% ), followed by tinea corporis and cruris (28. 8% ), onychomycosis (21.5%) , and tinea manus and tinea pedis (16.5%). Strain identification revealed that Trichophyton (T.) rubrum was the most common agent in this study ( 28.5% ), followed by T. mentagrophytes ( 22.3% ), Microsporun ( M. ) canis ( 18.8% ) and T. tonsurans ( 10.0% ). M. canis was the most common causative agent of tinea capitis ( 16.2% ). Statistical analysis showed that in different genders and nations, tinea corporis and cruris, tinea manus and tinea pedis had statistical difference ( P < 0.05 ); those disease were all common for men, with the incidence in Han people higher than in Uyghur people. In different ages, tinea capitis, onychomycosis, tinea corporis and cruris, tinea manus and tinea pedis had statistical difference ( P < 0.05 ). Onychomycosis, tinea corporis and cruris, tinea manus and tinea pedis were common in middle-aged people, while tinea capitis was common in children. Conclusion T. rubrum is the main etiologic agent of superficial mycosis in Urmuqi. Tinea capitis is the moat important superficial mycosis for children in this area. M. canis is the most common causative agent of tinea capitis.%目的 了解新疆乌鲁木齐市

  13. 韩语因果复句在汉语中的对应研究%A Correspondence Analysis of the Causational Claus-es in Chinese and Korean

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    Causational clauses exist both in Chinese and Korean, but these two languages belong to different families, resulting in great dif-ferences in techniques of expression and conjunctive devices. Korean causational clauses are correspondent not only to Chinese ones but also to other semantic clauses or forms. Causational clauses are studied widely in the research of general theories. However, few studies are based on Korean-Chinese translated novel corpus. This paper attempts to study causational clauses with actual bilingual examples taken from Korean-Chinese equivalent translational novel corpus. The compara-tive analysis of Chinese corresponding forms of causational clauses “-어서、-니까、-느라고、-므로” frequently used in Korean, is a good reference that may enlighten the study and teaching of Chinese- Koreancausational clauses.%中韩两种语言都存在因果复句,但因这两种语言分属不同语系,所以它们在复句的表现方法及连接手段上都有着很大差异,韩国语的因果复句不仅和汉语的因果复句相对应,而且还能和其他语义关系的复句或其他表现形式相对应。先行研究成果当中极少运用中韩对译小说语料库来研究复句的情况,尝试利用韩中对等翻译小说语料库进行复句研究,运用实际双语例句、使用比较分析法进行考察分析韩国语中使用频率较高的“-어서”、“-니까”、“-느라고”、“-므로”①等因果复句在汉语中的对应形式,这对于中韩复句的研究及教学将是一个很好的启示和参考。

  14. Evaluation of Antigens for Development of a Serological Test for Human African Trypanosomiasis (United States)

    Biéler, Sylvain; Waltenberger, Harald; Barrett, Michael P.; McCulloch, Richard; Mottram, Jeremy C.; Carrington, Mark; Schwaeble, Wilhelm; McKerrow, James; Phillips, Margaret A.; Michels, Paul A.; Büscher, Philippe; Sanchez, Jean-Charles; Bishop, Richard; Robinson, Derrick R.; Bangs, James; Ferguson, Michael; Nerima, Barbara; Albertini, Audrey; Michel, Gerd; Radwandska, Magdalena; Ndung’u, Joseph Mathu


    Background Control and elimination of human African trypanosomiasis (HAT) can be accelerated through the use of diagnostic tests that are more accurate and easier to deploy. The goal of this work was to evaluate the immuno-reactivity of antigens and identify candidates to be considered for development of a simple serological test for the detection of Trypanosoma brucei gambiense or T. b. rhodesiense infections, ideally both. Methodology/Principal Findings The reactivity of 35 antigens was independently evaluated by slot blot and ELISA against sera from both T. b. gambiense and T. b. rhodesiense infected patients and controls. The antigens that were most reactive by both tests to T. b. gambiense sera were the membrane proteins VSG LiTat 1.3, VSG LiTat 1.5 and ISG64. Reactivity to T. b. rhodesiense sera was highest with VSG LiTat 1.3, VSG LiTat 1.5 and SRA, although much lower than with T. b. gambiense samples. The reactivity of all possible combinations of antigens was also calculated. When the slot blot results of 2 antigens were paired, a VSG LiTat 1.3- ISG75 combination performed best on T. b. gambiense sera, while a VSG LiTat 1.3-VSG LiTat 1.5 combination was the most reactive using ELISA. A combination of SRA and either VSG LiTat 1.3 or VSG LiTat 1.5 had the highest reactivity on T. b. rhodesiense sera according to slot blot, while in ELISA, pairing SRA with either GM6 or VSG LiTat 1.3 yielded the best results. Conclusions This study identified antigens that were highly reactive to T. b. gambiense sera, which could be considered for developing a serological test for gambiense HAT, either individually or in combination. Antigens with potential for inclusion in a test for T. b. rhodesiense HAT were also identified, but because their reactivity was comparatively lower, a search for additional antigens would be required before developing a test for this form of the disease. PMID:27936225

  15. 沿海地区甲真菌病原菌构成分析%The analysis of causative pathogens of onychomycosis in coastal area

    Institute of Scientific and Technical Information of China (English)

    顾丽娟; 朱雪飞; 喻长法; 王成军


    Objective:To get the message of causative pathogens and constitution of onychomycosis in coastal are-a. Methods: A retrospective analysis was conducted on the fungal culture results of 382 cases of onychomycosis patients in nearly 3 years. Results: 382 strains of pathogenic fungi were isolated,the most frequently isolated fungus was dermatophytes (267 cases 69.9% ) , Trichophyton rubrum 186 cases (48.7% )ranked first,followed by Tricho-phyton mentagrophytes 39 cases ( 10. 2%). There were 91 yeast cases (23. 8%), Candida albicans 43 cases (11.3%) ranked first, followed by Candida glabrata 20 cases ( 5. 2 % ). There were 24 mould cases (6.3%), distal and lateral subungual onychomycosis( DLSO, 58. 9% ) were the most frequently clinical types, followed by TDO ( 23.0% ) , PSO (11.3%) and SWO (6.8%). Conclusion: The most frequently pathogenic fungus of onychomycosis were dermatophytes, yeasts and mould,the most frequently clinical types of onychomycosis were DLSO,TDO,PSO and SWO.%目的:了解沿海地区甲真菌病病原菌的种类和构成情况.方法:对近3年来我院皮肤科医治的382例甲屑培养阳性病例病原菌进行回顾性统计分析.结果:382株甲真菌病病原菌中皮肤癣菌267株,占69.9%,其中前二位分别为红色毛癣菌186株(48.7%)和须癣毛癣菌39株(1O.2%);酵母菌91株,占23.8%,其中前二位分别为白色假丝酵母菌43株(11.3%)和光滑假丝酵母菌20株(5.2%);霉菌24株,占6.3%.临床分型:远端甲下型(DLSO)占58.9%,全甲营养不良型(TDO)占23.0%,近端甲下型(PSO)占11.3%,浅表白色型(SWO)占6.8%.发病年龄以15岁~45岁居多,占74.9%.结论:甲真菌病病原菌以皮肤癣菌为主,其次为酵母菌和霉菌,临床分型以DLSO型为主,依次为TDO、PSO和SWO,发病年龄以15岁~ 45岁居多.

  16. Human African trypanosomiasis in endemic populations and travellers. (United States)

    Blum, J A; Neumayr, A L; Hatz, C F


    Human African trypanosomiasis (HAT) or sleeping sickness is caused by the protozoan parasites Trypanosoma brucei (T.b.) gambiense (West African form) and T.b. rhodesiense (East African form) that are transmitted by the bite of the tsetse fly, Glossina spp.. Whereas most patients in endemic populations are infected with T.b. gambiense, most tourists are infected with T.b. rhodesiense. In endemic populations, T.b. gambiense HAT is characterized by chronic and intermittent fever, headache, pruritus, and lymphadenopathy in the first stage and by sleep disturbances and neuro-psychiatric disorders in the second stage. Recent descriptions of the clinical presentation of T.b. rhodesiense in endemic populations show a high variability in different foci. The symptomatology of travellers is markedly different from the usual textbook descriptions of African HAT patients. The onset of both infections is almost invariably an acute and febrile disease. Diagnosis and treatment are difficult and rely mostly on old methods and drugs. However, new molecular diagnostic technologies are under development. A promising new drug combination is currently evaluated in a phase 3 b study and further new drugs are under evaluation.

  17. Causation chain of ship collision accident due to human error based on data mining technology%基于数据挖掘的船舶人为碰撞事故致因链研究

    Institute of Scientific and Technical Information of China (English)

    李红喜; 张连丰; 郑中义


    To effectively analyze the formation mechanism of ship collision accident , an accident causation chain was struc-tured based on Bayesian network and data mining algorithm . 128 cases of typical human errors caused ship collision acci-dents were analyzed , and the network structure of accident cause was built according to driver ’ s cognitive behavior for-mation process .Apriori algorithm and Java program were em-ployed to identify frequent occurrence human error , and the accident causation chain was formed.%为有效研究人为失误导致船舶碰撞事故的形成机理,采用贝叶斯网络结构和数据挖掘算法构建事故致因链。分析128起典型人为失误致因船舶碰撞事故案例,依据事故中驾驶员认知行为形成过程,采用贝叶斯网络构建事故致因网络结构;采用Apriori算法和JAVA语言编程挖掘事故的人为失误频繁因素组合,得出导致碰撞事故的人为失误致因链。

  18. Identification of non-peptidic cysteine reactive fragments as inhibitors of cysteine protease rhodesain. (United States)

    McShan, Danielle; Kathman, Stefan; Lowe, Brittiney; Xu, Ziyang; Zhan, Jennifer; Statsyuk, Alexander; Ogungbe, Ifedayo Victor


    Rhodesain, the major cathepsin L-like cysteine protease in the protozoan Trypanosoma brucei rhodesiense, the causative agent of African sleeping sickness, is a well-validated drug target. In this work, we used a fragment-based approach to identify inhibitors of this cysteine protease, and identified inhibitors of T. brucei. To discover inhibitors active against rhodesain and T. brucei, we screened a library of covalent fragments against rhodesain and conducted preliminary SAR studies. We envision that in vitro enzymatic assays will further expand the use of the covalent tethering method, a simple fragment-based drug discovery technique to discover covalent drug leads.

  19. Human African trypanosomiasis with 7-year incubation period: clinical, laboratory and neuroimaging findings. (United States)

    Wengert, Oliver; Kopp, Marcel; Siebert, Eberhard; Stenzel, Werner; Hegasy, Guido; Suttorp, Norbert; Stich, August; Zoller, Thomas


    Human African trypanosomiasis (HAT), also referred to as "sleeping sickness", is caused by the parasite Trypanosoma brucei. Diagnosing imported HAT outside endemic areas is difficult and diagnosis is often delayed. We report a case of imported human African trypanosomiasis caused by Trypanosoma brucei gambiense with an unusually long incubation period of at least 7 years. A 33 year old male African patient, a former resident of Cameroon, presented with a 4-month history of progressive personality changes. A few weeks before presentation the patient had first been admitted to a psychiatric ward and received antidepressant treatment, until a lumbar puncture showed pleocytosis and then antibiotic treatment for suspected neuroborreliosis was initiated. The patient continued to deteriorate during antibiotic treatment and became increasingly lethargic. Under antiparasitic and anti-inflammatory treatment, the condition of the patient gradually improved over the following months and he recovered completely after 24 months of follow-up. This well-documented case illustrates typical difficulties in establishing the correct diagnosis outside endemic areas and provides an overview of typical clinical, neuropathological and neuroimaging findings in T. b. gambiense trypanosomiasis, guiding the clinician in establishing the correct diagnosis in this rare disease.

  20. Identification of trans-sialidases as a common mediator of endothelial cell activation by African trypanosomes.

    Directory of Open Access Journals (Sweden)

    Zeinab Ammar

    Full Text Available Understanding African Trypanosomiasis (AT host-pathogen interaction is the key to an "anti-disease vaccine", a novel strategy to control AT. Here we provide a better insight into this poorly described interaction by characterizing the activation of a panel of endothelial cells by bloodstream forms of four African trypanosome species, known to interact with host endothelium. T. congolense, T. vivax, and T. b. gambiense activated the endothelial NF-κB pathway, but interestingly, not T. b. brucei. The parasitic TS (trans-sialidases mediated this NF-κB activation, remarkably via their lectin-like domain and induced production of pro-inflammatory molecules not only in vitro but also in vivo, suggesting a considerable impact on pathogenesis. For the first time, TS activity was identified in T. b. gambiense BSF which distinguishes it from the subspecies T. b. brucei. The corresponding TS were characterized and shown to activate endothelial cells, suggesting that TS represent a common mediator of endothelium activation among trypanosome species with divergent physiopathologies.

  1. A current analysis of chemotherapy strategies for the treatment of human African trypanosomiasis. (United States)

    Babokhov, Peter; Sanyaolu, Adekunle O; Oyibo, Wellington A; Fagbenro-Beyioku, Adetayo F; Iriemenam, Nnaemeka C


    Despite the recent advances in drug research, finding a safe, effective, and easy to use chemotherapy for human African trypanosomiasis (HAT) remains a challenging task. The four current anti-trypanosomiasis drugs have major disadvantages that limit more widespread use of these drugs in the endemic regions of sub-Saharan Africa. Pentamidine and suramin are limited by their effectiveness against the only first stage of Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, respectively. In addition, melarsoprol and eflornithine (two second stage drugs) each have disadvantages of their own. The former is toxic and has increasing treatment failures while the latter is expensive, laborious to administer, and lacks efficacy against T. b. rhodesiense. Furthermore, melarsoprol's toxicity and decreasing efficacy are glaring problems and phasing out the drug as a frontline treatment against T. b. gambiense is now possible with the emergence of competent, safe combination chemotherapies such as nifurtimox-eflornithine combination treatment (NECT). The future of eflornithine, on the other hand, is more promising. The drug is useful in the context of combination chemotherapy and potential orally administered analogues. Due to the limits of monotherapies, greater emphasis should be placed on the research and development of combination chemotherapies, based on the successful clinical tests with NECT and its current use as a frontline anti-trypanosomiasis treatment. This review discussed the current and future chemotherapy strategies for the treatment of HAT.

  2. Primary analyses on the causative species of a bloom in the Sanggou Bay%对桑沟湾海域一次藻华事件原因种的初步分析

    Institute of Scientific and Technical Information of China (English)

    孔凡洲; 于仁成; 张清春; 王云峰; 颜天; 周名江


    A unique picophytoplankton ( cell size around 2 mm) bloom occurred in June ,2011 in the Sanggou Bay. Phytoplankton samples were collected during the bloom on June I81,8th and 17th for microscopic observation and pigment analysis in the current study. Pigment analysis of the size - fractioned phytoplankton samples indicated that 19 - butanoyloxyfucoxanthin (But - fuco), fucoxanthin (Fuco), diadinoxanthin (Diad) and chlorophyll a (Chi a) were the major pigments of the bloom causative species. Based on the pigment profile, it's suggested that the bloom was caused by pelagophytes, haptophytes or silicoflagellate. CHEMTAX analysis indicated that the relative contributions of the bloom causative species to the bulk Chi a content of the phytoplankton samples were 62% on June 1" ,22% on June 8'11 and 97% on June 17, reflecting the predominant role of the bloom causative species in the phytoplankton community. The cell size and pigment composition of the bloom causative species in the Sanggou Bay are similar to the blooms in the coastal waters of Qinhuangdao, which suggests that the blooms be caused by the same or closely - related species. Features shared by these blooms,such as the extremely high cell density,small - sized and But - fuco containing cells,occurred in early summer,and the feeding - cessation effects on scallops, closely resemble the " brown tide" events caused by pelagophyte Aureococcus anophagefferens in the United States of America, which needs attention in the coming years.%2011年6月,桑沟湾海域爆发一种微微型藻类(藻细胞大小约2μm)形成的藻华.于6月1日、6月8日和6月17日采集的分级过滤浮游植物样品色素分析结果显示,19-丁酰氧基岩藻黄素(19-butanoyloxyfucoxanthin,But-fuco)、岩藻黄素(Fucoxanthin,Fuco)、硅甲藻黄素(Diadinoxanthin,Diad)和叶绿素a(Chlorophyll a,Chl a)等色素应是藻华原因种的主要色素组分.据此推断,藻华原因种可能属于海金藻类(Pelagophytes)、定鞭

  3. The causative gene and clinical features of various subtypes of spinocerebellar ataxia%脊髓小脑共济失调各亚型致病基因及临床表现

    Institute of Scientific and Technical Information of China (English)

    宋建萍; 杨丹; 陈涛; 李海江; 李方方


    脊髓小脑共济失调(SCAs)是一种严重致残、致死的神经系统遗传变性疾病,具有高度的临床异质性和遗传异质性.根据致病基因定位的不同,分为不同的亚型.SCAs通常以进行性共济失调为主要临床特征,临床诊断的难点在于各个亚型的临床表现之间相互重叠,因此将各型特有的临床表现、致病基因进行系统综述,有助于通过常见的临床表现对各亚型进行临床初诊,也使基因检测更具有针对性.%Spinocerebellar ataxia (SCAs) is a series of degenerative diseases of the nervous system that lead to disability and death,and has high clinical and genetic heterogeneity.According to different loci of the causative genes,SCAs can be divided into different subtypes.In general,progressive ataxia is the main clinical features of SCAs.The difficulty of clinical diagnosis is the overlapping of the clinical manifestations between various subtypes.Thus,systematically reviewing the unique clinical manifestations and causative genes of the subtypes of SCAs here will be beneficial to the initial clinical diagnosis and to targeting the gene sequencing accurately.

  4. 论医疗责任事实因果关系的诉讼证明%A Study of the Proceedings in Proving the Factual Causation Based on the Medical Liability

    Institute of Scientific and Technical Information of China (English)



    医疗责任事实因果关系具有复杂性,其证明非一般证明方法所能解决.目前比较有效的证明方法有表见证明和间接反证,重大医疗过失时可以减轻患方的证明责任乃至实行证明责任的转换.在发生证明妨碍行为时,可以做不利于妨碍方的事实推定.此外,概率认定因果关系理论、文件义务和诊断结果之作成与确保义务理论对医疗责任事实因果关系的证明亦具有一定的作用.盖然性说和优势证据理论亦可作为适当的参考.%Due to its complexity,the factual causation based on medical liability cannot be proved by general means.At present.there ale two rather effective fact-finding methods-Prima Facie Bewies and indirect rebuttal evidence.If major medical negligence occur8,the burden of proof of patient can be reduced or switched.In the event of proof obstruction,an adverse presumption of truth can be made for the obstructor.In addition,theory of fact-finding by probability,document obligations theory and theory of making the diagnosis and ensuring re-sponsibility also play a certain role in proving the causation based on the medical liability.The theory of proba-bilities and the theory of advantageous evidence can also be used as an advisable reference.

  5. Epidemic Characteristics and Causation for Sport Injury of Chinese Youthful Athletes of Ice and Snow Sports%我国冰雪项目青年运动员运动损伤流行病特点及致因

    Institute of Scientific and Technical Information of China (English)

    魏亚茹; 徐金庆; 刘志良; 高洪杰; 杨淑媛


    In order to prevent, reduce or avoid sports injury of Chinese youthful athletes of ice and snow sports, using the method of epidemiological research in the field of sports medicine, study on the characteristics and causation for sport injury of Chinese youthful athletes of ice and snow sports. The results showed that the incidence rate of sport injury of Chinese youthful athletes of ice and snow sports is higher, the rate of male athlets is higher than female, sports injury has the characteristics of repeatability and multiple. The rate of teenage ice hockey players and freestyle skiers is relatively higher. The knees, waists and ankles are greatest occurrence of sports injury. Diversified types of sports injuries, sprain, abrasions, contusions and fallings are common. The injuries of youthful athletes of ice and snow sports are based on acute injury and medium injury, minor injury. The mistakes of movements technique is the main causation for sport injury of Chinese youthful athletes of ice and snow sports.%为预防、减少或避免我国冰雪项目青年运动员的运动损伤,运用运动医学领域中研究流行病的方法,对我国冰雪项目青年运动员的运动损伤特点及致因进行研究.研究结果表明,我国冰雪项目青年运动员运动损伤发生率较高,男性运动员运动损伤的发病率高于女性,运动损伤具有重复性和多发性的特点;青年冰球运动员和自由式滑雪运动员运动损伤发生率相对较高;膝关节、腰背部和踝关节是运动损伤的高发部位;运动损伤的类型呈现多样化,扭伤、擦伤、挫伤及摔伤较为常见;冰雪项目青年运动员的伤病以急性损伤和中、轻度损伤为主;动作技术失误是导致我国冰雪项目青年运动员运动损伤的主要致因.

  6. 布氏锥虫未知CCCH-型锌指蛋白TbZC3H8功能特性的初步分析%Characterization of the hypothetical CCCH-type zinc-finger protein TbZC3H8 in Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    雷霁卿; 刘罗根; 郭学敏


    Objective To characterize the properties and functions of putative zinc-finger protein TbZC3H8 in Trypanosoma brucei.Methods Sequence analysis and motifs/domains prediction were performed through the protein database searches.An inducible RNAi cell line was generated to study the effect of TbZC3H8 repression on cell viability,and the RNAi knockdown efficiency was estimated by RT-QPCR and Western blot.The cell line ectopically expressing C-terminal mycTAP tagged TbZC3H8 was generated and used to identify the composition of TbZC3H8 protein complexes through the combination of tandem affinity purification and mass spectrometric analysis.Subcellular localization of the TbZC3H8 protein was determined by immunofluorescence microscopy.Results The CCCH zinc-finger motif of TbZC3H8 is highly conserved in kinetoplastid parasites.Repression of TbZC3H8 by RNAi resulted in the growth inhibition.The TbZC3H8 protein complex was found to contain both unknown proteins and RNA-binding proteins.TbZC3H8 was found to localize in the cytoplasm and the expression level was not changed upon the heat shock and serum starvation.Conclusion TbZC3H8 is essential for the growth of T.brucei.The binding of ZC3H8 with RNA-binding proteins suggested that ZC3H8 might play a role in RNA processing and metabolism.%目的 通过RNAi和蛋白复合物鉴定来初步分析布氏锥虫未知锌指蛋白TbZC3H8的特性及功能.方法 运用蛋白数据库和分析软件对TbZC3H8进行序列分析和结构域预测;构建RNAi诱导表达细胞株分析TbZC3H8经RNAi敲低后对锥虫生长的影响,并通过RT-QPCR和Western blot检测RNAi干扰效率;构建异位融合表达myc-TAP标签的TbZC3H8细胞株,采用串联亲和纯化合并质谱鉴定其蛋白复合物组成;采用免疫荧光分析蛋白定位.结果 TbZC3H8的CCCH结构域在动基体原虫中高度保守;RNAi下调TbZC3H8后明显抑制了锥虫复制;TbZC3H8蛋白复合物中包含多种未知蛋白

  7. 伊氏锥虫、马媾疫锥虫、布氏锥虫、刚果锥虫的18S rDNA部分序列测定与系统发育关系%Sequence and phylogenetic analysis of partial 18S rDNA gene for Trypanosoma evanis, Trypanosoma equiperdum, Trypanosoma brucei and Trypanosoma congolense isolates

    Institute of Scientific and Technical Information of China (English)

    周勇志; 周金林; 沈杰; 龚海燕; 向飞宇; 黄兵


    对伊氏锥虫(Trypanosoma evansi):新疆株(XJCA)、湖北株(HBM)、云南株(YNB)、广东株(GDB2);马媾疫锥虫(Trypanosoma equiperdum)、布氏锥虫(Trypanosoma brucei)、刚果锥虫(Trypanosoma congolense)提取基因组DNA,根据已报道的伊氏锥虫株18SrDNA基因序列设计合成引物,用PCR扩增了锥虫虫株基因组DNA,伊氏锥虫新疆株、湖北株、云南株、广东株、布氏锥虫、刚果锥虫均为373 bp的片段;马媾疫锥虫为372 bp的片段,PCR产物经电泳鉴定后用试剂盒回收纯化,纯化后PCR产物经连接、转化后测序,将测得的序列用DNAMAN软件分析并与国外已发表的相应序列进行了同源性比较,并绘制了系统发育进化树.结果与国外AJ009153、AJ223564、D89527株同源性达到99%~100%,与另外11株同源性75%.本研究为锥虫分子流行病学研究及分类研究打下基础.

  8. Comparison of the susceptibility of brown trout (Salmo trutta) and four rainbow trout (Oncorhynchus mykiss) strains to the myxozoan Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD). (United States)

    Grabner, Daniel S; El-Matbouli, Mansour


    Differences in susceptibility to the myxozoan parasite Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD), between four strains of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) were evaluated. Fish were exposed to water enzootic for the parasite in the field for 5 days and were subsequently transferred to the laboratory. Relative parasite load was determined after 2, 3 and 4 weeks post-exposure (wpe) by quantitative real-time PCR (qPCR) of kidney samples and number of parasite stages was determined in immunohistochemical stained sections of kidney, liver and spleen tissues. According to qPCR results, the highest amount of parasite DNA per equal amount of host tissue at all time points was measured in brown trout. Two of the rainbow trout strains showed lower relative parasite load than all other groups at the beginning of the experiment, but the parasite multiplied faster in these strains resulting in an equal level of relative parasite load for all rainbow trout strains at 4 wpe. A weak negative correlation of fish size and parasite load was detected. Only in samples of a few fish, single stages of T. bryosalmonae were found in sections stained by immunohistochemistry impeding quantitative evaluation of parasite numbers by this method. The results indicate a differential resistance to T. bryosalmonae between the rainbow trout strains investigated and between rainbow trout and brown trout.

  9. 关于我国医疗过失与因果关系之鉴定和认定的思考%Some Reflections on How to Establish Medical Negligence and Causation in Chinese Law

    Institute of Scientific and Technical Information of China (English)



    In establishing medical negligence and causation,Chinese law should(1) insist on expert and peer review,(2) protect both the patient's interests and the practitioner's interests,(3) acknowledge the difference between medical expert opinion and the judiciary legal judgment,(4) establish the distinct profile of medical negligence liability caused by breach of the duty to inform,and(5) draw distinctions among the "reasonable doctor" standard,the "medical level" standard and "medical custom" standard.%我国法律在医疗过失和因果关系的认定问题上,应坚持医疗"专家"判断和"同行"鉴定,旨力于构建平衡患者利益和医方利益的规则,区分医疗专家意见和法官法律判断,区分违反通常诊疗义务的医疗侵权和违反告知义务的医疗侵权,区分"合理医生"标准、"医疗水平"标准和"医疗常规"标准。

  10. Endogenous formation of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3- carboxylic acid in man as the possible causative substance of eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan. (United States)

    Adachi, J; Yamamoto, K; Ogawa, Y; Ueno, Y; Mizoi, Y; Tatsuno, Y


    1-Methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) is now thought to be a possible causative substance of eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan. In the present study a factor affecting endogenous formation of MTCA in 32 healthy men is studied. Urinary excretions of MTCA and 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (TCCA) were measured by high-performance liquid chromatography (HPLC) with fluorometric detection after administration of a high or low protein diet as well as peroral tryptophan (0.5 g) or ethanol (0.4 g/kg). Blood ethanol and acetaldehyde levels were determined by gas chromatography after ethanol consumption. Both, the high protein diet and tryptophan resulted in a significant rise of urinary TCCA. In contrast, ethanol intake caused increased excretion of MTCA, though a relationship between blood acetaldehyde level and urinary excretion of MTCA was not shown. We showed for the first time that an elevation of urinary excretion of MTCA following ethanol consumption in man without ingestion of L-tryptophan tablets implicated eosinophilia-myalgia syndrome.

  11. Ultrashallow seismic imaging of the causative fault of the 1980, M6.9, southern Italy earthquake by pre-stack depth migration of dense wide-aperture data (United States)

    Bruno, Pier Paolo; Castiello, Antonio; Improta, Luigi


    A two-step imaging procedure, including pre-stack depth migration (PSDM) and non-linear multiscale refraction tomography, was applied to dense wide-aperture data with the aim of imaging the causative fault of the 1980, M6.9, Irpinia normal faulting earthquake in a very complex geologic environment. PSDM is often ineffective for ultrashallow imaging (100 m of depth and less) of laterally heterogeneous media because of the difficulty in estimating a correct velocity model for migration. Dense wide-aperture profiling allowed us to build accurate velocity models across the fault zone by multiscale tomography and to record wide-angle reflections from steep reflectors. PSDM provided better imaging with respect to conventional post-stack depth migration, and improved definition of fault geometry and apparent cumulative displacement. Results indicate that this imaging strategy can be very effective for near-surface fault detection and characterization. Fault location and geometry are in agreement with paleoseismic data from two nearby trenches. The estimated vertical fault throw is only 29-38 m. This value, combined with the vertical slip rate determined by trench data, suggests a young age (97-127 kyr) of fault inception.

  12. Sex, handedness, mathematical ability, and biological causation. (United States)

    Peters, M


    An important part of Benbow's (1988) assertion that sex differences in mathematical ability are primarily due to biological factors is the link between a trait that is assumed to reflect differences in brain organization (left-handedness) and mathematical giftedness. It is shown that the link between mathematical giftedness and an increased prevalence of left-handedness is not convincing. However, Benbow's (1986) data do show a convincing link between strong right-handedness and the lack of mathematical giftedness, in agreement with Annett and Manning's (1990a, 1990b) recent work.

  13. Indexation and causation of financial markets

    CERN Document Server

    Tanokura, Yoko


    This book presents a new statistical method of constructing a price index of a financial asset where the price distributions are skewed and heavy-tailed and investigates the effectiveness of the method. In order to fully reflect the movements of prices or returns on a financial asset, the index should reflect their distributions. However, they are often heavy-tailed and possibly skewed, and identifying them directly is not easy. This book first develops an index construction method depending on the price distributions, by using nonstationary time series analysis. Firstly, the long-term trend of the distributions of the optimal Box–Cox transformed prices is estimated by fitting a trend model with time-varying observation noises. By applying state space modeling, the estimation is performed and missing observations are automatically interpolated. Finally, the index is defined by taking the inverse Box–Cox transformation of the optimal long-term trend. This book applies the method to various financial data. ...

  14. Neonatal Brachial Plexus Palsy and Causation

    LENUS (Irish Health Repository)

    Turner, M J


    A vaginal childbirth is the result of the internal (endogenous) expulsive forces of uterine contractions, usually supplemented by active maternal pushing1. Depending on the clinical circumstances, additional external (exogenous) traction forces may be required from the birth attendant. This blend of internal and external forces varies from birth to birth. Women who have had a previous vaginal delivery, for example, may deliver successfully with uterine contractions alone and the role of the birth attendant may be simply to control and slow the delivery so that trauma to the maternal perineum from stretching by the fetal head is minimised. In contrast, additional traction may be required by an obstetrician at the time of an operative vaginal delivery for fetal distress or dystocia. The strength of the traction required may be increased by clinical factors, for example, fetal macrosomia or malposition. The traction should be axial in the direction of the birth canal, which is a vector combining horizontal and vertical traction at 25-45 degrees below the horizontal when the woman is in the lithotomy position.

  15. Causation and models of disease in epidemiology. (United States)

    Broadbent, Alex


    Nineteenth-century medical advances were entwined with a conceptual innovation: the idea that many cases of disease which were previously thought to have diverse causes could be explained by the action of a single kind of cause, for example a certain bacterial or parasitic infestation. The focus of modern epidemiology, however, is on chronic non-communicable diseases, which frequently do not seem to be attributable to any single causal factor. This paper is an effort to resolve the resulting tension. The paper criticises the monocausal model of disease, so successful in the nineteenth century. It also argues that a multifactorial model of disease can only be satisfactory if it amounts to more than a mere rejection of the monocausal model. A third alternative, the contrastive model, is proposed and defended on the grounds that it links the notions of disease and of general explanation, while avoiding the philosophical naiveties and practical difficulties of the monocausal model.

  16. Microbiologically Influenced Corrosion: Causative Organisms and Mechanisms (United States)


    a membrane, within which DNA is formed into distinct chromosomes. Eukaryotic cells also contain mitochondria and other structures organelles that...nucleus or any oilier organdies within their cells. Generally, archaea and bacteria are similar in size and shape, although a lew archaea have very...unusual shapes, such as the Hat and square-shaped cells. Despite the visual similarity to bacteria, archaea possess unique biochemistries, genes and

  17. Active causation and the origin of meaning

    NARCIS (Netherlands)

    van Hateren, J.H.


    Purpose and meaning are necessary concepts for understanding mind and culture, but appear to be absent from the physical world and are not part of the explanatory framework of the natural sciences. Understanding how meaning (in the broad sense of the term) could arise from a physical world has prove

  18. Causation, explanation and nonmonotonic temporal reasoning

    NARCIS (Netherlands)

    Grünwald, P.D.


    We introduce a new approach to reasoning about action and change using nonmonotonic logic. The approach is arrived at by applying Pearl's theory of causal networks to logical formalizations of temporal reasoning domains. It handles complicated reasoning domains involving concurrent actions, actions

  19. Nutrient intakes: cancer causation and prevention. (United States)

    Leonard, T K; Mohs, M E; Watson, R R


    High intakes of the macronutrients--proteins, lipids, and carbohydrates in the form of excess energy-have some cancer stimulating properties. On the contrary, epidemiologic and animal laboratory data indicate that high-level supplementation of some micronutrients--certain vitamins, minerals, and lipotropes, as well as some non-nutrients, most notably various types of dietary fiber, may be useful in the prevention of cancer. A wealth of data exists for macronutrients whereas most micronutrients are almost unstudied concerning their role in cancer prevention. Vitamins A, E, and C and selenium are the most well-studied micronutrients, and are recognized as effective with significant anticancer effects, at least in animal models. There are minimal data to suggest that some other micronutrients may also exert varying degrees of incidence reduction on one or more types of cancer. This is most true for folic acid, manganese, molybdenum, copper, the amino acids phenylalanine and methionine, and the lipotrope choline. Zinc and vitamins B1, B2, B6, B12 and pantothenic acid have even less data, and some data are contradictory. Therefore, it is premature to make recommendations concerning their usefulness in cancer prevention at present.

  20. Causation and complexity: old lessons, new crusades. (United States)

    Layng, T V


    A body of experimental work performed by Israel Goldiamond and his colleagues over 30 years ago is used to help define the evidential problems raised for inferences concerning the causal efficacy of human thought. This work suggests that matches of public indicator responses of inferred private rules or states to experimenter score sheets may be considered only as weak evidence for causality. Further, the problems of inferring causality raised by Wittgenstein's skeptical challenge, and its implications for investigating the role of human thought in determining human behavior, are briefly described. A selectionist approach, which is currently being used by biobehavioral scientists to investigate the behavioral complexity which concerns Bandura (this issue) and others, is suggested as one way to study the role of private events in human behavior.

  1. Williamson on knowledge, action, and causation

    DEFF Research Database (Denmark)

    Steglich-Petersen, Asbjørn


    argue that although Williamson succeeds in establishing that knowledge in some cases is essential to the power of certain causal explanations of actions, he fails to do this in a way that establishes knowledge itself as a causal factor. The argument thus fails to support his overall claim that knowledge......In his Knowledge and its Limits (2000) Timothy Williamson argues that knowledge can be causally efficacious and as such figure in psychological explanation. His argument for this claim figures as a response to a key objection to his overall thesis that knowing is a mental state. In this paper I...

  2. Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese sleeping sickness focus of the Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Simo Gustave


    Full Text Available Abstract Background The Malanga sleeping sickness focus of the Democratic Republic of Congo has shown an epidemic evolution of disease during the last century. However, following case detection and treatment, the prevalence of the disease decreased considerably. No active survey has been undertaken in this focus for a couple of years. To understand the current epidemiological status of sleeping sickness as well as the animal African trypanosomiasis in the Malanga focus, we undertook the identification of tsetse blood meals as well as different trypanosome species in flies trapped in this focus. Methods Pyramidal traps were use to trap tsetse flies. All flies caught were identified and live flies were dissected and their mid-guts collected. Fly mid-gut was used for the molecular identification of the blood meal source, as well as for the presence of different trypanosome species. Results About 949 Glossina palpalis palpalis were trapped; 296 (31.2% of which were dissected, 60 (20.3% blood meals collected and 57 (19.3% trypanosome infections identified. The infection rates were 13.4%, 5.1%, 3.5% and 0.4% for Trypanosoma congolense savannah type, Trypanosoma brucei s.l., Trypanosoma congolense forest type and Trypanosoma vivax, respectively. Three mixed infections including Trypanosoma brucei s.l. and Trypanosoma congolense savannah type, and one mixed infection of Trypanosoma vivax and Trypanosoma congolense savannah type were identified. Eleven Trypanosoma brucei gambiense infections were identified; indicating an active circulation of this trypanosome subspecies. Of all the identified blood meals, about 58.3% were identified as being taken on pigs, while 33.3% and 8.3% were from man and other mammals, respectively. Conclusion The presence of Trypanosoma brucei in tsetse mid-guts associated with human blood meals is indicative of an active transmission of this parasite between tsetse and man. The considerable number of pig blood meals combined

  3. 高速公路尾随相撞事件的贝叶斯网络致因分析模型%Bayesian Netw ork M odeling for Causation Analysis of Highw ay Rear-end Collision

    Institute of Scientific and Technical Information of China (English)

    张兰芳; 彭川子; 杨晓萍


    By the use of 1104 recorded Shanghai highway incidents ,the topological structure of BN (Bayesian network) was formed with references to expert knowledge and data fusion method .Bayes-ian method was used to complete the process of parameter learning with Dirichlet prior distribution . Network analyzes were inferred using Clique tree propagation algorithm engine .The paper studied the relationship between rear-end collision and different road environment .After Verifying the effective-ness of the Bayesian network model ,the causation of incident was analyzed and improvement measures were proposed .Inference results indicate that significant rear-end collision easily occurs between large and medium-sized trucks and small car .large and medium-sized trucks easily happen to significant rear-end collision in the evening ,especially from 0 :00 to 6:00 .Significant rear-end collision easily oc-curs to the wet road surface of unordinary road by large and medium-sized coaches .Bayesian network is the useful method of traffic incident cause analysis to reflect the multidimensional and associated na-ture of the incidents causation .%应用上海市高速公路1104条事件数据,基于专家知识和数据融合方法建立贝叶斯网络结构;利用服从Dirichlet分布的贝叶斯方法进行参数学习;运用团树传播算法进行推理分析。研究了上海市高速公路尾随相撞事件类型与不同道路环境条件之间的关系。在验证贝叶斯网络模型的有效性后,系统分析事件致因,并提出改进措施。发现重大尾随相撞事件易发生在大中型车与小型车之间;夜间易发生大中型货车的重大尾随相撞事件,尤其是凌晨0时至6时;路表潮湿状态下的非普通路段上易发生大中型客车的重大尾随相撞事件。结果表明贝叶斯网络建模能够更好的反映事件致因因素的多维性及关联性,是交通事件致因分析的有效方法。

  4. 冰球运动员腰背肌筋膜炎的原因和防治措施%Causation, Treatment and Precaution on the Ice Hockey Players' Lumbar and Dorsal Myofascitis

    Institute of Scientific and Technical Information of China (English)

    杨勇; 臧克成; 尹炳南


    腰背肌筋膜炎在冰球运动员群体中是最常见的运动损伤之一,这与该项目在运动过程中,身体多在弯腰时击球发力有关,如预防和治疗不正确、不及时,不仅会严重影响运动员的运动寿命,甚至影响今后的日常生活。分析和总结了冰球运动员腰背肌筋膜损伤的原因、临床表现、诊断方法、治疗措施和预防手段,以期帮助冰球运动员科学训练并积极配合医务人员,有效地避免和减少腰背肌筋膜炎的发生及其带来的不良影响。%The ice hockey players'lumbar and dorsal myofascitis is one of the most common athletic injuries, which is related with their frequently stooping to drive the puck. Wrong or delayed treatment and precaution will badly influence their athletic life and even their future daily living. In order to help them have more scientific training and actively cooperate with the medical workers, effectively avoid and reduce the injury and its adverse effects, it discusses the injury's causation, clinical feature, diagnostic method, therapeutic measures and precaution.

  5. The effect of the causative algae of large-scale HAB in the East China Sea on egg hatching of Argopecten irradians, and population growth of Brachionus plicatilis and Moina mongolica

    Institute of Scientific and Technical Information of China (English)

    CHEN Taoying; YAN Tian; WANG Liping; ZHANG Bin; ZHOU Mingjiang


    The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monoculture and mixture of the two species were examined on the egg-hatching success of Argopecten irradians Lamarck, and the population growth of Brachionus plicatilis Müller and Moina mongolica Daday. The results showed that monoculture of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities (EDs0) inhibiting the egg hatching success of A. irradians for 24 h and the population growth of B. plicatilis and M.mongolica for 96 h were 800, 630, and 2 400 cells/cm3, respectively. Monoculture of P. donghaiense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis ( 1 × 104 ~ 3 × 104 cells/cm3 ) and M. mongolica (2 × 104 ~ 5 × 104 cells/cm3 ); P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis (4 × 104 ~ 10 × 104 cells/cm3 ) and M. mongolica ( 10 ×104 cells/cm3). When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.

  6. 生命早期抗生素使用与儿童哮喘:因果关系还是混杂效应?%Antibiotic use in early life and childhood asthma:causation or confounding?

    Institute of Scientific and Technical Information of China (English)



    儿童哮喘的发病率逐年上升.基于卫生假说,抗生素使用可能减少了微生物暴露,从而增加了过敏性疾病发生的风险.近十年来,就早期抗生素暴露与儿童哮喘的关系进行的大量的流行病学调查的结果并不一致.大多数回顾性研究发现正相关联系,但前瞻性研究未发现联系或联系强度较弱.逆向因果和指示混淆可部分解释两者的关系,但也难以否定因果关系的存在.%The prevalence of childhood asthma has been increased yearly.Based on the hygiene hypothesis,the antibiotic use may increase the risk of the allergic disease by reducing microbial exposure.In the last decade,a number of epidemiological studies have been conducted on the association between early exposure of antibiotic and childhood asthma,and the results are not consistent.The majority retrospective studies have found a positive association but the prospective studies have showed a null or weak association.Reverse causation and confounding-by-indication may partly explain the relation.But it is difficult to deny a causal link between antibiotic use and asthma.

  7. 东胜煤田塔然高勒矿井井筒坍塌原因分析%Collapsing Causation Analysis of Taran Gol Shaft in Dongsheng Coalfield

    Institute of Scientific and Technical Information of China (English)



    The Taran Gol coalmine in the Dongsheng coalfield, Inner Mongolia is a constructing large-sized state-run vertical shaft coalmine belongs to the Hanggin Energy Co. Ltd., Shenhua Group Corporation Limited, using the conventional shaft sinking. During the construction process, shaft collapsing accident has happened and caused superior economic losses. Afterwards, special shaft sinking by freezing has been used and won through. Based on shaft engineering geological conditions, preliminarily analyzed shaft collapsing causations, have considered that soft strata and low strength are the natural factors, improper construction method and technology the human factors. The study has certain referential value in shaft sinking construction in the area.%内蒙古自治区东胜煤田塔然高勒矿井是神华杭锦能源有限责任公司在建的大型国有矿井,矿井采用立井开采,立并井筒采用普通法施工.在施工过程中发生了并简坍塌事故,造成了较大的经济损失.后采用特殊法施工(冻结法),获得了成功.在研究井筒工程地质条件的基础上,对井筒坍塌的原因进行了初步分析,认为井筒地层松软、强度低是造成井筒坍塌的自然因素,采用了不适合的施工方法和技术是造成井筒坍塌的人为因素.该研究对本区井简施工具有一定的参考价值.

  8. Immunodiagnosis of bovine trypanosomiasis in Anambra and Imo states, Nigeria, using enzyme-linked immunosorbent assay: zoonotic implications to human health

    Directory of Open Access Journals (Sweden)

    M.C. Ezeani


    Full Text Available Background & objectives: The prevalence of trypanosomiasis was studied in cattle, being a major source of animal protein in Nigeria, thus, a very likely means of spread of Human African Trypano-somosis (HAT. Methods: Enzyme-linked immunosorbent assay (ELISA was used to diagnose bovine trypanosomiasis in 264 samples collected from adult cattle of mixed breeds, age and sex, in Anambra and Imo states, Nigeria. Results: Out of 264 samples analysed, 21 (7.96% were seropositive for Trypanosoma congolense while 20 (7.58% were seropositive for T. vivax and 8 (3.03% were seropositive for T. brucei infections in both the states. Interpretation & conclusion: The predominant species was found to be T. congolense. Mixed infection of three species, T. vivax, T. congolense and T. brucei was found to dominate other mixed infections in both the states. ELISA detected the infection of the three species of trypanosomes in the same group of animals. The usefulness of antigen capture ELISA in the diagnosis of human or animal trypanosomiasis was established, and the possibility of the spread of HAT caused by T. brucei gambiense and T.b. rhodesiense through cattle was expressed.

  9. Human African trypanosomiasis: a review of non-endemic cases in the past 20 years. (United States)

    Migchelsen, Stephanie J; Büscher, Philippe; Hoepelman, Andy I M; Schallig, Henk D F H; Adams, Emily R


    Human African trypanosomiasis (HAT) is caused by sub-species of the parasitic protozoan Trypanosoma brucei and is transmitted by tsetse flies, both of which are endemic only to sub-Saharan Africa. Several cases have been reported in non-endemic areas, such as North America and Europe, due to travelers, ex-patriots or military personnel returning from abroad or due to immigrants from endemic areas. In this paper, non-endemic cases reported over the past 20 years are reviewed; a total of 68 cases are reported, 19 cases of Trypanosoma brucei gambiense HAT and 49 cases of Trypanosoma brucei rhodesiense HAT. Patients ranged in age from 19 months to 72 years and all but two patients survived. Physicians in non-endemic areas should be aware of the signs and symptoms of this disease, as well as methods of diagnosis and treatment, especially as travel to HAT endemic areas increases. We recommend extension of the current surveillance systems such as TropNetEurop and maintaining and promotion of existing reference centers of diagnostics and expertise. Important contact information is also included, should physicians require assistance in diagnosing or treating HAT.

  10. Production and preliminary evaluation of Trypanosoma evansi HSP70 for antibody detection in Equids. (United States)

    Kumar, Jaideep; Chaudhury, Ashok; Bera, Bidhan C; Kumar, Ritesh; Kumar, Rajender; Tatu, Utpal; Yadav, Suresh Chandra


    The present immuno-diagnostic method using soluble antigens from whole cell lysate antigen for trypanosomosis have certain inherent problems like lack of standardized and reproducible antigens, as well as ethical issues due to in vivo production, that could be alleviated by in vitro production. In the present study we have identified heat shock protein 70 (HSP70) from T. evansi proteome. The nucleotide sequence of T. evansi HSP70 was 2116 bp, which encodes 690 amino acid residues. The phylogenetic analysis of T. evansi HSP70 showed that T. evansi occurred within Trypanosoma clade and is most closely related to T. brucei brucei and T. brucei gambiense, whereas T. congolense HSP70 laid in separate clade. The two partial HSP70 sequences (HSP-1 from N-terminal region and HSP-2 from C-terminal region) were expressed and evaluated as diagnostic antigens using experimentally infected equine serum samples. Both recombinant proteins detected antibody in immunoblot using serum samples from experimental infected donkeys with T. evansi. Recombinant HSP-2 showed comparable antibody response to Whole cell lysate (WCL) antigen in immunoblot and ELISA. The initial results indicated that HSP70 has potential to detect the T. evansi infection and needs further validation on large set of equine serum samples.

  11. The detection and treatment of human African trypanosomiasis

    Directory of Open Access Journals (Sweden)

    Bouteille B


    Full Text Available Bernard Bouteille,1 Alain Buguet21Laboratory of Parasitology, Dupuytren University Hospital of Limoges, France; 2Polyclinic Marie-Louise Poto-Djembo, Pointe-Noire, CongoAbstract: Human African trypanosomiasis (HAT is caused by the injection of Trypanosoma brucei (T. b. gambiense or T. b. rhodesiense by Glossina, the tsetse fly. Three historical eras followed the exclusive clinical approach of the 19th century. At the turn of the century, the “initial research” era was initiated because of the dramatic spread of HAT throughout intertropical Africa, and scientists discovered the agent and its vector. Two entities, recurrent fever and sleeping sickness, were then considered a continuum between hemolymphatic stage 1 and meningoencephalitic stage 2. Treatments were developed. Soon after World War I, specific services and mobile teams were created, initiating the “epidemiological” era, during which populations were visited, screened, and treated. As a result, by 1960, annual new cases were rare. New mass screening and staging tools were then developed in a third, “modern” era, especially to counter a new epidemic wave. Currently, diagnosis still relies on microscopic detection of trypanosomes without (wet and thick blood films or with concentration techniques (capillary tube centrifugation, miniature anion-exchange centrifugation technique. Staging is a vital step.Stage 1 patients are treated on site with pentamidine or suramin. However, stage 2 patients are treated in specialized facilities, using drugs that are highly toxic and/or that require complex administration procedures (melarsoprol, eflornithine, or nifurtimox-eflornithine combination therapy. Suramin and melarsoprol are the only medications active against Rhodesian HAT. Staging still relies on cerebrospinal fluid examination for trypanosome detection and white blood cell counts: stage 1, absence of trypanosomes, white blood cell counts ≤ 5/µL; stage 2, presence of

  12. Comparison of the Therapeutic Effects of Four Antiparasitic Protozoan Drugs on Trypanosoma evansi, T. equiperdum and T. b.brucei in Mice%四种抗寄生原虫药物对伊氏锥虫、马媾疫锥虫和布氏锥虫感染的治疗作用

    Institute of Scientific and Technical Information of China (English)

    戴晓俐; 赖德华; 伦照荣


    目的 研究分析伊氏锥虫(Trypanosoma evansi)、马媾疫锥虫(T.equiperdum)和布氏锥虫指名亚种(T.b.brucei)对四种抗寄生原虫药物(氯喹、甲硝唑、Mel Cy和贝尼尔)抗性的差异,及药物剂量和治疗时间对治疗效果的影响.方法 将105锥虫经腹腔接种小鼠,感染后于不同时间用不同剂量的药物对小鼠进行治疗,观察小鼠虫血症的变化和死亡情况.结果 氯喹和甲硝唑在单用或合用时对这3种锥虫没有可见的疗效,MelCy与贝尼尔则具有良好的治疗效果;其中1.6 mg/kg的Mel Cy对3种锥虫都有完全的治愈作用;贝尼尔在7 mg/kg的剂量水平对马媾疫锥虫和布氏锥虫也有完全的杀灭作用.马媾疫锥虫和布氏锥虫对贝尼尔敏感,但伊氏锥虫对贝尼尔则表现出明显的抗药性.提高药物的注射剂量或在感染早期治疗可以延长感染小鼠的存活时间.结论 伊氏锥虫对所用药物的抗性最强,其次为布氏锥虫指名亚种,马媾疫锥虫对药物最敏感.加大药物注射剂量和感染后及早治疗可提高治愈率.

  13. Some Comments on Wittgenstein' s Proposition of Law of Causation in Tractatus Logica-Philosophicus%“因果”与“逻辑”——读维特根斯坦《逻辑哲学论》关于“因果律”的命题有感

    Institute of Scientific and Technical Information of China (English)



    因果问题是哲学的基本问题之一,《逻辑哲学论》中的"因果律"命题廓清了原因与结果之关系的实质。与逻辑推理相比,因果律根基于两个经验事实在时间上的承接关系,即逻辑推理追问理由,因果原则探求原因,这就是因果关系的哲学本质。%The issue of causality is one of the basic issues in the history of philosophy.The proposition of "law of causation" in Tractatus Logica-Philosophicus can explain the complex philosophical issue.Comparing to logical inference,the law of causation is rooted in the diachronic connection between two empiristic facts.The human search after a "reason" in local inference and find a "cause" in causation inference,it is just the metaphysic foundation of causation itself.

  14. Causation,Treatment and Precaution on the Speed Skaters' Patella Strain%速滑运动员髌骨劳损的原因和防治措施

    Institute of Scientific and Technical Information of China (English)

    高文岳; 臧克成; 尹炳南; 宋克宁


    The speed skaters' patella strain is one of the most common athletic injuries,which is related with the knee joint's adductive or abductive exerting force with half squat in skating.Wrong or delayed treatment and precaution will badly influence their athletic life and even their future daily living.After discussing the causation of speed skaters' patella strain,the paper elaborates the means of treating the knee joint's acute injury.In order to help them have more scientific training and actively cooperate with the medical workers,effectively avoid and reduce the injury and its adverse effects,it indicates how to prevent the injury from following aspects: improve the athletic talents' identification;pay attention to the strength training of quadriceps femoris;enhance the training of flexibility,coordination and proprioceptive sensibility;reinforce the stability and balance force of knee joint muscles.%膝关节髌骨劳损在速滑专业运动员群体中是最常见的运动损伤之一,这与该项目在运动过程中,膝关节多在半蹲位内收或外展发力有关,如预防和治疗不正确、不及时,不仅会严重速滑影响运动员的运动寿命,甚至还会影响今后的日常生活。从多方面分析和总结了速滑运动员髌骨劳损的原因,阐述了膝关节急性损伤的处理等治疗措施,指出从运动员选材,注重股四头肌肌肉力量的训练,加强柔韧性、协调性和本体感受性的训练,保持肌肉平衡及关节稳定性等方面对速滑运动员的髌骨劳损进行预防,以期帮助运动员科学训练并积极配合医务人员,有效地避免和减少髌骨劳损的发生及其带来的不良影响。

  15. A study of anemia in human immunodeficiency virus patients: Estimating the prevalence, analyzing the causative effect of nutritional deficiencies, and correlating the degree of severity with CD4 cell counts

    Directory of Open Access Journals (Sweden)

    Ajay Panwar


    Full Text Available Background: Anemia is a common complication of human immunodeficiency virus (HIV infection. The role of iron, Vitamin B12, and folate deficiencies, which are otherwise most common causes of anemia, is not well-established in HIV patients. Several studies in India have shown that severe immunodeficiency is associated with higher grade of anemia, but correlation of CD4 cell counts with severity of anemia is not well-documented. Aims: The aims of the present study were: To estimate the point prevalence of anemia in HIV patients, to analyze the causative role of iron, Vitamin B12, and folate deficiencies in anemic HIV patients, and correlating the degree of severity of anemia with CD4 cell counts. Materials and Methods: This study was a cross-sectional study. The study group enrolled 103 consecutive HIV patients attending medical emergency, medical outpatient department, medical wards, and anti-retroviral therapy (ART center at a tertiary care medical center in North India. Study participation consisted of a single visit during which relevant data, including medical history, current medications, CD4 T-lymphocyte count, complete hemogram with red blood cell indices, peripheral smear picture, iron studies, serum Vitamin B12, serum folate and bone marrow studies, were recorded on a case report form. Anemia was classified according to the World Health Organization criteria. Data analysis was carried out using Microsoft Excel and Statistical Package for the Social Sciences software. Results: 86.4% (89/103 patients were found to be anemic. There was no significant difference in prevalence of anemia in ART-naive patients from those who were on ART (P > 0.05. Pearson′s correlation had shown a highly significant positive correlation of hemoglobin and CD4 cell counts in male patients (r = 0.418 as well as female patients (r = 0.565. Normocytic normochromic was the most common type of anemia in males (46% as well as females (42%. Significant iron deficiency

  16. Sleeping sickness (United States)

    ... include: Eflornithine (for T. b. gambiense only) Melarsoprol Pentamidine (for T. b. gambiense only) Suramin (Antrypol) Some ... Pentamidine injections protect against T. b. gambiense, but not against T. b. rhodesiense . Because this medicine is ...

  17. 喉接触性肉芽肿的病因分析及非手术治疗的疗效分析%Analysis on the causative factors of laryngeal contact granuloma and the therapeutic effect of non-operative therapy on this kind of lesion

    Institute of Scientific and Technical Information of China (English)

    程磊; 黎长江; 吴海涛


    目的 探讨喉接触性肉芽肿的病因及非手术疗法的疗效.方法 喉接触性肉芽肿患者49例,回顾性分析其相关临床资料,探讨其发病因素,总结去除病因疗法结合口服中成药玄柏爽声方治疗的临床效果.结果 本组病例的相关发病因素有慢性喉炎(49例,100%)、喉咽返流(27例,55%)、用声过度(23例,占47%)、饮酒(20例,占41%)、吸烟(18例,37%)和不明原因(7例,占14.7%)等.经非手术疗法治疗后,36例(74%)肉芽组织全部消失,肉芽消失时间为3~13月,平均8.6个月.有喉咽返流的接触性喉肉芽肿患者治愈率为75%(20/27),用声过度、吸烟和饮酒的患者,其治愈率分别为63%(14/23)、83%(15/18)、79%(16/20),不明病因患者的治愈率为71%(5/7).不同病因所致肉芽肿患者亚组间的疗效差异无统计学意义(P>0.05).结论 喉接触性肉芽肿常为多种病因所致,去除病因疗法结合口服中成药玄柏爽声方治疗可获明显疗效.%Objective To explore the causative factors of laryngeal contact granuloma and the therapeutic effect of non-operative therapy on this kind of lesion based on a clinical trial. Method Included in this study were 49 cases with laryngeal contact granuloma treated at our Hospital from Mar., 2011 to Feb., 2015, with their all clinical data analyzed in a retrospective way to explore the possibly associated causative factors and the therapeutic effect of a non-operative therapy, mainly composed of herbal preparation Shuangsheng Granules orally taken. Result The related causative factors among these 49 cases included chronic pharyngitis (49, 100%), laryngopharyngeal reflux (27, 55%), inappropriate vocal use (23, 47%), alcohol consumption (20, 41%), smoking (18, 37%) as well as those with causative factor undefined(7, 14.7%), ranked in a declining order. Following the treatment of non-operative therapy, granuloma was completely disappeared in a majority of patients(36/49, 74%) 3 to 13 months following the non

  18. Cardiac alterations in human African trypanosomiasis (T.b. gambiense with respect to the disease stage and antiparasitic treatment.

    Directory of Open Access Journals (Sweden)

    Johannes A Blum

    Full Text Available BACKGROUND: In Human African Trypanosomiasis, neurological symptoms dominate and cardiac involvement has been suggested. Because of increasing resistance to the available drugs for HAT, new compounds are desperately needed. Evaluation of cardiotoxicity is one parameter of drug safety, but without knowledge of the baseline heart involvement in HAT, cardiologic findings and drug-induced alterations will be difficult to interpret. The aims of the study were to assess the frequency and characteristics of electrocardiographic findings in the first stage of HAT, to compare these findings to those of second stage patients and healthy controls and to assess any potential effects of different therapeutic antiparasitic compounds with respect to ECG changes after treatment. METHODS: Four hundred and six patients with first stage HAT were recruited in the Democratic Republic of Congo, Angola and Sudan between 2002 and 2007 in a series of clinical trials comparing the efficacy and safety of the experimental treatment DB289 to the standard first stage treatment, pentamidine. These ECGs were compared to the ECGs of healthy volunteers (n = 61 and to those of second stage HAT patients (n = 56. RESULTS: In first and second stage HAT, a prolonged QTc interval, repolarization changes and low voltage were significantly more frequent than in healthy controls. Treatment in first stage was associated with repolarization changes in both the DB289 and the pentamidine group to a similar extent. The QTc interval did not change during treatment. CONCLUSIONS: Cardiac involvement in HAT, as demonstrated by ECG alterations, appears early in the evolution of the disease. The prolongation of the QTC interval comprises a risk of fatal arrhythmias if new drugs with an additional potential of QTC prolongation will be used. During treatment ECG abnormalities such as repolarization changes consistent with peri-myocarditis occur frequently and appear to be associated with the disease stage, but not with a specific drug.

  19. Beyond Tsetse--Implications for Research and Control of Human African Trypanosomiasis Epidemics. (United States)

    Welburn, Susan C; Molyneux, David H; Maudlin, Ian


    Epidemics of both forms of human African trypanosomiasis (HAT) are confined to spatially stable foci in Sub-Saharan Africa while tsetse distribution is widespread. Infection ra