WorldWideScience

Sample records for c2 toxin gene

  1. Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin

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    Masaya Takehara

    2017-08-01

    Full Text Available Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins.

  2. Cellular uptake of Clostridium botulinum C2 toxin requires oligomerization and acidification

    NARCIS (Netherlands)

    Barth, H; Blocker, D; Behlke, J; Bergsma-Schutter, W; Brisson, A; Benz, R; Aktories, K

    2000-01-01

    The actin-ADP-ribosylating binary Clostridium botulinum C2 toxin consists of two individual proteins, the binding/translocation component C2II and the enzyme component C2I. To elicit its cytotoxic action, C2II binds to a receptor on the cell surface and mediates cell entry of C2I via

  3. Gene Therapy and Targeted Toxins for Glioma

    Science.gov (United States)

    Castro, Maria G.; Candolfi, Marianela; Kroeger, Kurt; King, Gwendalyn D.; Curtin, James F.; Yagiz, Kader; Mineharu, Yohei; Assi, Hikmat; Wibowo, Mia; Muhammad, AKM Ghulam; Foulad, David; Puntel, Mariana; Lowenstein, Pedro R.

    2011-01-01

    The most common primary brain tumor in adults is glioblastoma. These tumors are highly invasive and aggressive with a mean survival time of nine to twelve months from diagnosis to death. Current treatment modalities are unable to significantly prolong survival in patients diagnosed with glioblastoma. As such, glioma is an attractive target for developing novel therapeutic approaches utilizing gene therapy. This review will examine the available preclinical models for glioma including xenographs, syngeneic and genetic models. Several promising therapeutic targets are currently being pursued in pre-clinical investigations. These targets will be reviewed by mechanism of action, i.e., conditional cytotoxic, targeted toxins, oncolytic viruses, tumor suppressors/oncogenes, and immune stimulatory approaches. Preclinical gene therapy paradigms aim to determine which strategies will provide rapid tumor regression and long-term protection from recurrence. While a wide range of potential targets are being investigated preclinically, only the most efficacious are further transitioned into clinical trial paradigms. Clinical trials reported to date are summarized including results from conditionally cytotoxic, targeted toxins, oncolytic viruses and oncogene targeting approaches. Clinical trial results have not been as robust as preclinical models predicted; this could be due to the limitations of the GBM models employed. Once this is addressed, and we develop effective gene therapies in models that better replicate the clinical scenario, gene therapy will provide a powerful approach to treat and manage brain tumors. PMID:21453286

  4. Alternaria Toxins: Potential Virulence Factors and Genes Related to Pathogenesis

    Science.gov (United States)

    Meena, Mukesh; Gupta, Sanjay K.; Swapnil, Prashant; Zehra, Andleeb; Dubey, Manish K.; Upadhyay, Ram S.

    2017-01-01

    Alternaria is an important fungus to study due to their different life style from saprophytes to endophytes and a very successful fungal pathogen that causes diseases to a number of economically important crops. Alternaria species have been well-characterized for the production of different host-specific toxins (HSTs) and non-host specific toxins (nHSTs) which depend upon their physiological and morphological stages. The pathogenicity of Alternaria species depends on host susceptibility or resistance as well as quantitative production of HSTs and nHSTs. These toxins are chemically low molecular weight secondary metabolites (SMs). The effects of toxins are mainly on different parts of cells like mitochondria, chloroplast, plasma membrane, Golgi complex, nucleus, etc. Alternaria species produce several nHSTs such as brefeldin A, tenuazonic acid, tentoxin, and zinniol. HSTs that act in very low concentrations affect only certain plant varieties or genotype and play a role in determining the host range of specificity of plant pathogens. The commonly known HSTs are AAL-, AK-, AM-, AF-, ACR-, and ACT-toxins which are named by their host specificity and these toxins are classified into different family groups. The HSTs are differentiated on the basis of bio-statistical and other molecular analyses. All these toxins have different mode of action, biochemical reactions and signaling mechanisms to cause diseases. Different species of Alternaria produced toxins which reveal its biochemical and genetic effects on itself as well as on its host cells tissues. The genes responsible for the production of HSTs are found on the conditionally dispensable chromosomes (CDCs) which have been well characterized. Different bio-statistical methods like basic local alignment search tool (BLAST) data analysis used for the annotation of gene prediction, pathogenicity-related genes may provide surprising knowledge in present and future. PMID:28848500

  5. Alternaria Toxins: Potential Virulence Factors and Genes Related to Pathogenesis

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    Mukesh Meena

    2017-08-01

    Full Text Available Alternaria is an important fungus to study due to their different life style from saprophytes to endophytes and a very successful fungal pathogen that causes diseases to a number of economically important crops. Alternaria species have been well-characterized for the production of different host-specific toxins (HSTs and non-host specific toxins (nHSTs which depend upon their physiological and morphological stages. The pathogenicity of Alternaria species depends on host susceptibility or resistance as well as quantitative production of HSTs and nHSTs. These toxins are chemically low molecular weight secondary metabolites (SMs. The effects of toxins are mainly on different parts of cells like mitochondria, chloroplast, plasma membrane, Golgi complex, nucleus, etc. Alternaria species produce several nHSTs such as brefeldin A, tenuazonic acid, tentoxin, and zinniol. HSTs that act in very low concentrations affect only certain plant varieties or genotype and play a role in determining the host range of specificity of plant pathogens. The commonly known HSTs are AAL-, AK-, AM-, AF-, ACR-, and ACT-toxins which are named by their host specificity and these toxins are classified into different family groups. The HSTs are differentiated on the basis of bio-statistical and other molecular analyses. All these toxins have different mode of action, biochemical reactions and signaling mechanisms to cause diseases. Different species of Alternaria produced toxins which reveal its biochemical and genetic effects on itself as well as on its host cells tissues. The genes responsible for the production of HSTs are found on the conditionally dispensable chromosomes (CDCs which have been well characterized. Different bio-statistical methods like basic local alignment search tool (BLAST data analysis used for the annotation of gene prediction, pathogenicity-related genes may provide surprising knowledge in present and future.

  6. Gene-trap mutagenesis identifies mammalian genes contributing to intoxication by Clostridium perfringens ε-toxin.

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    Susan E Ivie

    Full Text Available The Clostridium perfringens ε-toxin is an extremely potent toxin associated with lethal toxemias in domesticated ruminants and may be toxic to humans. Intoxication results in fluid accumulation in various tissues, most notably in the brain and kidneys. Previous studies suggest that the toxin is a pore-forming toxin, leading to dysregulated ion homeostasis and ultimately cell death. However, mammalian host factors that likely contribute to ε-toxin-induced cytotoxicity are poorly understood. A library of insertional mutant Madin Darby canine kidney (MDCK cells, which are highly susceptible to the lethal affects of ε-toxin, was used to select clones of cells resistant to ε-toxin-induced cytotoxicity. The genes mutated in 9 surviving resistant cell clones were identified. We focused additional experiments on one of the identified genes as a means of validating the experimental approach. Gene expression microarray analysis revealed that one of the identified genes, hepatitis A virus cellular receptor 1 (HAVCR1, KIM-1, TIM1, is more abundantly expressed in human kidney cell lines than it is expressed in human cells known to be resistant to ε-toxin. One human kidney cell line, ACHN, was found to be sensitive to the toxin and expresses a larger isoform of the HAVCR1 protein than the HAVCR1 protein expressed by other, toxin-resistant human kidney cell lines. RNA interference studies in MDCK and in ACHN cells confirmed that HAVCR1 contributes to ε-toxin-induced cytotoxicity. Additionally, ε-toxin was shown to bind to HAVCR1 in vitro. The results of this study indicate that HAVCR1 and the other genes identified through the use of gene-trap mutagenesis and RNA interference strategies represent important targets for investigation of the process by which ε-toxin induces cell death and new targets for potential therapeutic intervention.

  7. An Emulsion Based Microarray Method to Detect the Toxin Genes of Toxin-Producing Organisms

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    Yunfei Bai

    2011-08-01

    Full Text Available Toxins produced by bacteria and fungi are one of the most important factors which may cause food contamination. The study of detection methods with high sensitivity and throughput is significant for the protection of food safety. In the present study, we coupled microarray with emulsion PCR and developed a high throughput detection method. Thirteen different gene sites which encode the common toxins of several bacteria and fungi were assayed in parallel in positive and maize samples. Conventional PCR assays were carried out for comparison. The results showed that the developed microarray method had high specificity and sensitivity. Two zearalenone-related genes were investigated in one of the ten maize samples obtained with this present method. The results indicated that the emulsion based microarray detection method was developed successfully and suggested its potential application in multiple gene site detection.

  8. Plankton composition, biomass, phylogeny and toxin genes in Lake ...

    African Journals Online (AJOL)

    Plankton composition, biomass, phylogeny and toxin genes in Lake Big Momela, Tanzania. ... cyanobacteria during the whole year. In general, our data illustrate the presence of rich planktonic communities, including some unique and potentially endemic cyanobacteria. Keywords: cyanotoxin, limnology, plankton diversity, ...

  9. Phylogenetic analysis of Shiga toxin 1 and Shiga toxin 2 genes associated with disease outbreaks

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    Farrell Larry D

    2007-12-01

    Full Text Available Abstract Background Shiga toxins 1 and 2 (Stx1 and Stx2 are bacteriophage-encoded proteins that have been associated with hemorrhagic colitis, hemolytic uremic syndrome and other severe disease conditions. Stx1 and Stx2 are genetically and immunologically distinct but share the same compound toxin structure, method of entry and enzymatic function. Results Phylogenetic analysis was performed using Stx1 and Stx2 amino acid and nucleotide sequences from 41 strains of Escherichia coli, along with known stx sequences available from GenBank. The analysis confirmed the Stx1 and Stx2 divergence, and showed that there is generally more sequence variation among stx2 genes than stx1. The phylograms showed generally flat topologies among our strains' stx1 and stx2 genes. In the stx2 gene, 39.5% of the amino acid sites display very low nonsynonymous to synonymous substitution ratios. Conclusion The stx1 and stx2 genes used in this phylogenetic study show sequence conservation with no significant divergence with respect to place or time. These data could indicate that Shiga toxins are experiencing purifying selection.

  10. Bacterial Toxins for Oncoleaking Suicidal Cancer Gene Therapy.

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    Pahle, Jessica; Walther, Wolfgang

    For suicide gene therapy, initially prodrug-converting enzymes (gene-directed enzyme-producing therapy, GDEPT) were employed to intracellularly metabolize non-toxic prodrugs into toxic compounds, leading to the effective suicidal killing of the transfected tumor cells. In this regard, the suicide gene therapy has demonstrated its potential for efficient tumor eradication. Numerous suicide genes of viral or bacterial origin were isolated, characterized, and extensively tested in vitro and in vivo, demonstrating their therapeutic potential even in clinical trials to treat cancers of different entities. Apart from this, growing efforts are made to generate more targeted and more effective suicide gene systems for cancer gene therapy. In this regard, bacterial toxins are an alternative to the classical GDEPT strategy, which add to the broad spectrum of different suicide approaches. In this context, lytic bacterial toxins, such as streptolysin O (SLO) or the claudin-targeted Clostridium perfringens enterotoxin (CPE) represent attractive new types of suicide oncoleaking genes. They permit as pore-forming proteins rapid and also selective toxicity toward a broad range of cancers. In this chapter, we describe the generation and use of SLO as well as of CPE-based gene therapies for the effective tumor cell eradication as promising, novel suicide gene approach particularly for treatment of therapy refractory tumors.

  11. Functional analysis of a putative Dothistromin toxin MFS transporter gene.

    Science.gov (United States)

    Bradshaw, Rosie E; Feng, Zhilun; Schwelm, Arne; Yang, Yongzhi; Zhang, Shuguang

    2009-12-01

    Dothistromin is a non-host selective toxin produced by the pine needle pathogen Dothistroma septosporum. Dothistromin is not required for pathogenicity, but may have a role in competition and niche protection. To determine how D. septosporum tolerates its own toxin, a putative dothistromin transporter, dotC, was investigated. Studies with mutants lacking a functional dotC gene, overproducing dotC, or with a dotC-GFP fusion gene, did not provide conclusive evidence of a role in dothistromin efflux. The mutants revealed a major effect of dotC on dothistromin biosynthesis but were resistant to exogenous dothistromin. Intracellular localization studies suggest that compartmentalization may be important for dothistromin tolerance.

  12. Detection of RTX toxin genes in gram-negative bacteria with a set of specific probes.

    OpenAIRE

    Kuhnert, P; Heyberger-Meyer, B; Burnens, A P; Nicolet, J; Frey, J.

    1997-01-01

    The family of RTX (RTX representing repeats in the structural toxin) toxins is composed of several protein toxins with a characteristic nonapeptide glycine-rich repeat motif. Most of its members were shown to have cytolytic activity. By comparing the genetic relationships of the RTX toxin genes we established a set of 10 gene probes to be used for screening as-yet-unknown RTX toxin genes in bacterial species. The probes include parts of apxIA, apxIIA, and apxIIIA from Actinobacillus pleuropne...

  13. Recurrent horizontal transfer of bacterial toxin genes to eukaryotes.

    Science.gov (United States)

    Moran, Yehu; Fredman, David; Szczesny, Pawel; Grynberg, Marcin; Technau, Ulrich

    2012-09-01

    In this work, we report likely recurrent horizontal (lateral) gene transfer events of genes encoding pore-forming toxins of the aerolysin family between species belonging to different kingdoms of life. Clustering based on pairwise similarity and phylogenetic analysis revealed several distinct aerolysin sequence groups, each containing proteins from multiple kingdoms of life. These results strongly support at least six independent transfer events between distantly related phyla in the evolutionary history of one protein family and discount selective retention of ancestral genes as a plausible explanation for this patchy phylogenetic distribution. We discuss the possible roles of these proteins and show evidence for a convergent new function in two extant species. We hypothesize that certain gene families are more likely to be maintained following horizontal gene transfer from commensal or pathogenic organism to its host if they 1) can function alone; and 2) are immediately beneficial for the ecology of the organism, as in the case of pore-forming toxins which can be utilized in multicellular organisms for defense and predation.

  14. Detection of RTX toxin genes in gram-negative bacteria with a set of specific probes.

    Science.gov (United States)

    Kuhnert, P; Heyberger-Meyer, B; Burnens, A P; Nicolet, J; Frey, J

    1997-06-01

    The family of RTX (RTX representing repeats in the structural toxin) toxins is composed of several protein toxins with a characteristic nonapeptide glycine-rich repeat motif. Most of its members were shown to have cytolytic activity. By comparing the genetic relationships of the RTX toxin genes we established a set of 10 gene probes to be used for screening as-yet-unknown RTX toxin genes in bacterial species. The probes include parts of apxIA, apxIIA, and apxIIIA from Actinobacillus pleuropneumoniae, cyaA from Bordetella pertusis, frpA from Neisseria meningitidis, prtC from Erwinia chrysanthemi, hlyA and elyA from Escherichia coli, aaltA from Actinobacillus actinomycetemcomitans and lktA from Pasteurella haemolytica. A panel of pathogenic and nonpathogenic gram-negative bacteria were investigated for the presence of RTX toxin genes. The probes detected all known genes for RTX toxins. Moreover, we found potential RTX toxin genes in several pathogenic bacterial species for which no such toxins are known yet. This indicates that RTX or RTX-like toxins are widely distributed among pathogenic gram-negative bacteria. The probes generated by PCR and the hybridization method were optimized to allow broad-range screening for RTX toxin genes in one step. This included the binding of unlabelled probes to a nylon filter and subsequent hybridization of the filter with labelled genomic DNA of the strain to be tested. The method constitutes a powerful tool for the assessment of the potential pathogenicity of poorly characterized strains intended to be used in biotechnological applications. Moreover, it is useful for the detection of already-known or new RTX toxin genes in bacteria of medical importance.

  15. Molecular cloning of Clostridium septicum vaccine strain alpha toxin gene in E. coli

    OpenAIRE

    Bozorgkhoo; Pilehchian Langroudi; Khaki; Jabbari; Moradi Bidhendi; Moosawi Shoshtari

    2014-01-01

    Clostridium septicum a Gram positive anaerobic bacterium produces several toxins including alpha, beta, gamma and delta. C. septicum alpha toxin is lethal and is responsible for a serious disease known as gas gangrene. The aim of the present study was to molecular cloning and sequencing of C. septicum vaccine strain alpha toxin gene. Genomic DNA was extracted using standard phenol and chloroform extraction method, and the target gene was amplified through PCR by specific primers. Quality and ...

  16. Horizontal gene transfer of toxin genes in Clostridium botulinum: Involvement of mobile elements and plasmids.

    Science.gov (United States)

    Skarin, Hanna; Segerman, Bo

    2011-09-01

    Intoxication with the potent botulinum neurotoxin (BoNT) gives rise to the serious paralytic illness botulism. BoNT is part of a complex that consists of the neurotoxin and several associated components, all encoded by the bont gene cluster. This gene cluster has likely been subjected to horizontal gene transfer between different groups of clostridia, which has given rise to the genetically diverse species Clostridium botulinum. C. botulinum is divided into four physiological groups (I-IV), where group I and II cause disease in humans and group III in animals. Analysis of the genomes of group I, II and III has revealed that toxin genes, including the bont cluster, often are plasmid-borne. The genomes analyzed from group III contain an unusually high number of plasmids carrying different toxin genes. Some of these genes are also found in other Clostridium species and some have moved between different plasmids within the same physiological group. This indicates that horizontal transfer of toxin genes is taking place within and between species of Clostridium. The abundance of mobile elements, especially in genomes of group III, is likely connected to accelerated genome plasticity and gene transfer events.

  17. Prediction of Toxin Genes from Chinese Yellow Catfish Based on Transcriptomic and Proteomic Sequencing

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    Bing Xie

    2016-04-01

    Full Text Available Fish venom remains a virtually untapped resource. There are so few fish toxin sequences for reference, which increases the difficulty to study toxins from venomous fish and to develop efficient and fast methods to dig out toxin genes or proteins. Here, we utilized Chinese yellow catfish (Pelteobagrus fulvidraco as our research object, since it is a representative species in Siluriformes with its venom glands embedded in the pectoral and dorsal fins. In this study, we set up an in-house toxin database and a novel toxin-discovering protocol to dig out precise toxin genes by combination of transcriptomic and proteomic sequencing. Finally, we obtained 15 putative toxin proteins distributed in five groups, namely Veficolin, Ink toxin, Adamalysin, Za2G and CRISP toxin. It seems that we have developed a novel bioinformatics method, through which we could identify toxin proteins with high confidence. Meanwhile, these toxins can also be useful for comparative studies in other fish and development of potential drugs.

  18. The molecular diversity of toxin gene families in lethal Amanita mushrooms.

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    Li, Peng; Deng, Wangqiu; Li, Taihui

    2014-06-01

    Mushrooms in lethal Amanita species are responsible for a large number of food poisoning cases and deaths. However, the diversity of the toxins in these mushrooms remains largely unknown. This study analyzed the gene families of toxins found in 6 lethal Amanitae from Asia and Europe. Fifty-four gene sequences were obtained, accounting for 70.1% of the known MSDIN family members. Of the 54 gene sequences, 20 encode α-amanitin, 5 encode β-amanitin, 16 encode phallacidin, and 13 encode peptides of unknown functions. Bayesian analysis of MSDIN family members identified differences in the number of toxin genes in different toxin families among the Amanita species. Ten of the 13 peptides of unknown functions were closely related to known phallotoxins, while the remaining 3 were similar to amatoxins. The α-AMA tree indicated that there were significant differences between the Amanita and Galerina species. However, both the α-AMA and PHA trees showed that these toxin genes have similar upstream and downstream motif sequences among the Amanita species. This study greatly enriches the available diversity information regarding toxin gene families in lethal Amanita mushrooms, and could lay a strong foundation for further research about the evolution of Amanita toxin genes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Gene family encoding the major toxins of lethal Amanita mushrooms.

    Science.gov (United States)

    Hallen, Heather E; Luo, Hong; Scott-Craig, John S; Walton, Jonathan D

    2007-11-27

    Amatoxins, the lethal constituents of poisonous mushrooms in the genus Amanita, are bicyclic octapeptides. Two genes in A. bisporigera, AMA1 and PHA1, directly encode alpha-amanitin, an amatoxin, and the related bicyclic heptapeptide phallacidin, a phallotoxin, indicating that these compounds are synthesized on ribosomes and not by nonribosomal peptide synthetases. alpha-Amanitin and phallacidin are synthesized as proproteins of 35 and 34 amino acids, respectively, from which they are predicted to be cleaved by a prolyl oligopeptidase. AMA1 and PHA1 are present in other toxic species of Amanita section Phalloidae but are absent from nontoxic species in other sections. The genomes of A. bisporigera and A. phalloides contain multiple sequences related to AMA1 and PHA1. The predicted protein products of this family of genes are characterized by a hypervariable "toxin" region capable of encoding a wide variety of peptides of 7-10 amino acids flanked by conserved sequences. Our results suggest that these fungi have a broad capacity to synthesize cyclic peptides on ribosomes.

  20. Cloning and sequence analysis of genes encoding Staphylococcus hyicus exfoliative toxin types A, B, C, and D

    DEFF Research Database (Denmark)

    Ahrens, Peter; Andresen, Lars Ole

    2004-01-01

    Exfoliative toxins produced by certain strains of Staphylococcus hyicus mediate exudative epidermitis in pigs. In this study the genes coding for four different exfoliative toxin from S. hyicus (ExhA, ExhB, ExhC, and ExhD) were cloned and sequenced. The coding sequence of the four toxin genes ran...

  1. Enigma homolog 1 promotes myogenic gene expression and differentiation of C2C12 cells.

    Science.gov (United States)

    Ito, Jumpei; Takita, Masatoshi; Takimoto, Koichi; Maturana, Andrés D

    2013-06-07

    The Enigma homolog (ENH) gene generates several splicing variants. The initially identified ENH1 possesses one PDZ and three LIM domains, whereas ENH2~4 lack the latter domains. The splicing switch from ENH1 to LIM-less ENHs occurs during development/maturation of skeletal and heart muscles. We examined for the roles of ENH splicing variants in muscle differentiation using C2C12 cells. Cells stably expressing ENH1 exhibited significantly higher MyoD and myogenin mRNA levels before differentiation and after 5 days in low serum-differentiating medium than mock-transfected cells. ENH1-stable transformants also retained the ability to exhibit elongated morphology with well-extended actin fibers following differentiation. In contrast, cells stably expressing ENH3 or ENH4 did not show myotube-like morphology or reorganization of actin fibers following culture in the differentiating medium. Transient overexpression of ENH1 using adenovirus supported the increased expression of muscle marker mRNAs and the formation of well-organized stress fibers, whereas ENH4 overexpression prevented these morphological changes. Furthermore, specific suppression of ENH1 expression by RNAi caused a significant reduction in MyoD mRNA level and blocked the morphological changes. These results suggest that ENH1 with multiple protein-protein interaction modules is essential for differentiation of striated muscles, whereas ectopic expression of LIM-less ENH disrupts normal muscle differentiation. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Evolution of C2H2-zinc finger genes and subfamilies in mammals: Species-specific duplication and loss of clusters, genes and effector domains

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    Aubry Muriel

    2008-06-01

    Full Text Available Abstract Background C2H2 zinc finger genes (C2H2-ZNF constitute the largest class of transcription factors in humans and one of the largest gene families in mammals. Often arranged in clusters in the genome, these genes are thought to have undergone a massive expansion in vertebrates, primarily by tandem duplication. However, this view is based on limited datasets restricted to a single chromosome or a specific subset of genes belonging to the large KRAB domain-containing C2H2-ZNF subfamily. Results Here, we present the first comprehensive study of the evolution of the C2H2-ZNF family in mammals. We assembled the complete repertoire of human C2H2-ZNF genes (718 in total, about 70% of which are organized into 81 clusters across all chromosomes. Based on an analysis of their N-terminal effector domains, we identified two new C2H2-ZNF subfamilies encoding genes with a SET or a HOMEO domain. We searched for the syntenic counterparts of the human clusters in other mammals for which complete gene data are available: chimpanzee, mouse, rat and dog. Cross-species comparisons show a large variation in the numbers of C2H2-ZNF genes within homologous mammalian clusters, suggesting differential patterns of evolution. Phylogenetic analysis of selected clusters reveals that the disparity in C2H2-ZNF gene repertoires across mammals not only originates from differential gene duplication but also from gene loss. Further, we discovered variations among orthologs in the number of zinc finger motifs and association of the effector domains, the latter often undergoing sequence degeneration. Combined with phylogenetic studies, physical maps and an analysis of the exon-intron organization of genes from the SCAN and KRAB domains-containing subfamilies, this result suggests that the SCAN subfamily emerged first, followed by the SCAN-KRAB and finally by the KRAB subfamily. Conclusion Our results are in agreement with the "birth and death hypothesis" for the evolution of

  3. Detection of Clostridium perfringens toxin genes in the gut microbiota of autistic children.

    Science.gov (United States)

    Finegold, Sydney M; Summanen, Paula H; Downes, Julia; Corbett, Karen; Komoriya, Tomoe

    2017-06-01

    We studied stool specimens from 33 autistic children aged 2-9 years with gastrointestinal (GI) abnormalities and 13 control children without autism and without GI symptoms. We performed quantitative comparison of all Clostridium species and Clostridium perfringens strains from the fecal microbiota by conventional, selective anaerobic culture methods. We isolated C. perfringens strains and performed PCR analysis for the main C. perfringens toxin genes, alpha, beta, beta2, epsilon, iota and C. perfringens enterotoxin gene. Our results indicate that autistic subjects with gastrointestinal disease harbor statistically significantly (p = 0.031) higher counts of C. perfringens in their gut compared to control children. Autistic subjects also harbor statistically significantly (p = 0.015) higher counts of beta2-toxin gene-producing C. perfringens in their gut compared to control children, and the incidence of beta2-toxin gene-producing C. perfringens is significantly higher in autistic subjects compared to control children (p = 0.014). Alpha toxin gene was detected in all C. perfringens strains studied. C. perfringens enterotoxin gene was detected from three autistic and one control subject. Beta, epsilon, and iota toxin genes were not detected from autistic or control subjects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Detection of Shiga toxins genes by Multiplex PCR in clinical samples

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    2013-09-01

    Full Text Available Background: Different methods have been used for detection of shiga toxins; such as,  cell culture, ELISA, and RFPLA. However, all of these methods suffer from high cost, time-consumption and relatively low sensitivity. In this study we used Multiplex PCR method for detection of genes encoding shiga toxins. Material and Methods: In this study, 63 clinical samples were obtained from positive cultures of Shigella and E. coli O157, from Bahman 1391 until Ordibehesht 1392 in Mazandaran province. Initial confirmation of shiga toxins producing bacteria was performed by biochemical and serological methods. After DNA extraction, detection of stx1 and stx2 genes was accomplished by multiplex PCR.  For confirmation of the PCR amplicon, DNA sequencing was used. Antibiotic sensitivity tests were performed by disk diffusion method. Results:  Among the positive strains, 13 strains contained stx2 genes, 4 strains contained Stx/Stx1 genes and 4 strains harbored both Stx/Stx1 and Stx2. The DNA extracted from other Gram-negative bacteria was not protected by the relevant parts of these toxins. Sequencing of the amplified fragments indicated the correct toxin sequences.  The sensitivity for identification of Stx/Stx1 gene was 1.56 pg/ µl and for Stx2 was 1.08 pg/µl. The toxin positive strains were all sensitive to Cefixime, Gentamicin, Amikacin, Ceftriaxone, and Nitrofurantoin. Conclusion: This method is fast and accurate for detection of bacteria producing shiga toxin and can be used to identify different types of shiga toxin.

  5. Bacterial toxin-antitoxin gene system as containment control in yeast cells

    DEFF Research Database (Denmark)

    Kristoffersen, P.; Jensen, G. B.; Gerdes, K.

    2000-01-01

    The potential of a bacterial toxin-antitoxin gene system for use in containment control in eukaryotes was explored. The Escherichia coli relE and relB genes were expressed in the yeast Saccharomyces cerevisiae, Expression of the relE gene was highly toxic to yeast cells. However, expression...... of the relB gene counteracted the effect of relE to some extent, suggesting that toxin-antitoxin interaction also occurs in S. cerevisiae, Thus, bacterial toxin-antitoxin gene systems also have potential applications in the control of cell proliferation in eukaryotic cells, especially in those industrial...... fermentation processes in which the escape of genetically modified cells would be considered highly risky....

  6. Evolutionary genomics of plant genes encoding N-terminal-TM-C2 domain proteins and the similar FAM62 genes and synaptotagmin genes of metazoans

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    Craxton Molly

    2007-07-01

    Full Text Available Abstract Background Synaptotagmin genes are found in animal genomes and are known to function in the nervous system. Genes with a similar domain architecture as well as sequence similarity to synaptotagmin C2 domains have also been found in plant genomes. The plant genes share an additional region of sequence similarity with a group of animal genes named FAM62. FAM62 genes also have a similar domain architecture. Little is known about the functions of the plant genes and animal FAM62 genes. Indeed, many members of the large and diverse Syt gene family await functional characterization. Understanding the evolutionary relationships among these genes will help to realize the full implications of functional studies and lead to improved genome annotation. Results I collected and compared plant Syt-like sequences from the primary nucleotide sequence databases at NCBI. The collection comprises six groups of plant genes conserved in embryophytes: NTMC2Type1 to NTMC2Type6. I collected and compared metazoan FAM62 sequences and identified some similar sequences from other eukaryotic lineages. I found evidence of RNA editing and alternative splicing. I compared the intron patterns of Syt genes. I also compared Rabphilin and Doc2 genes. Conclusion Genes encoding proteins with N-terminal-transmembrane-C2 domain architectures resembling synaptotagmins, are widespread in eukaryotes. A collection of these genes is presented here. The collection provides a resource for studies of intron evolution. I have classified the collection into homologous gene families according to distinctive patterns of sequence conservation and intron position. The evolutionary histories of these gene families are traceable through the appearance of family members in different eukaryotic lineages. Assuming an intron-rich eukaryotic ancestor, the conserved intron patterns distinctive of individual gene families, indicate independent origins of Syt, FAM62 and NTMC2 genes. Resemblances

  7. A multiplex PCR for detection of genes encoding exfoliative toxins from Staphylococcus hyicus

    DEFF Research Database (Denmark)

    Andresen, Lars Ole; Ahrens, Peter

    2004-01-01

    Aims: To develop a multiplex PCR for detection of genes encoding the exfoliative toxins ExhA, ExhB, ExhC and ExhD from Staphylococcus hyicus and to estimate the prevalence of exfoliative toxins among Staph. hyicus isolates from Danish pig herds with exudative epidermitis (EE). Methods and Results......: A multiplex PCR employing specific primers for each of the genes encoding four different exfoliative toxins was developed and evaluated using a collection of Staph. hyicus with known toxin type and a number of other staphylococcal species. A total of 314 Staph. hyicus isolates from pigs with EE were screened...... by multiplex PCR and the combined results of the present and previous investigations showed that ExhA, ExhB, ExhC and ExhD was found in 20, 33, 18 and 22%, respectively, of 60 cases of EE investigated. Conclusions: This study has provided a new tool for detection of toxigenic Staph. hyicus and a more...

  8. Dynamics of plc gene transcription and alpha-toxin production during growth of Clostridium perfringens strains with contrasting alpha-toxin production.

    Science.gov (United States)

    Abildgaard, Lone; Schramm, Andreas; Rudi, Knut; Højberg, Ole

    2009-10-20

    The aim of the present study was to investigate transcription dynamics of the alpha-toxin-encoding plc gene relative to two housekeeping genes (gyrA and rplL) in batch cultures of three Clostridium perfringens strains with low, intermediate, and high levels of alpha-toxin production, respectively. The plc transcript level was always low in the low alpha-toxin producing strain. For the two other strains, plc transcription showed an inducible pattern and reached a maximum level in the late exponential growth phase. The transcription levels were however inversely correlated to alpha-toxin production for the two strains. We propose that this discrepancy is due to differences in plc translation rates between the strains and that strain-specific translational rates therefore must be determined before alpha-toxin production can be extrapolated from transcript levels in C. perfringens.

  9. Dynamics of plc gene transcription and α-toxin production during growth of Clostridium perfringens strains with contrasting α-toxin production

    DEFF Research Database (Denmark)

    Abildgaard, Lone; Schramm, Andreas; Rudi, Knut

    2009-01-01

    The aim of the present study was to investigate transcription dynamics of the α-toxin-encoding plc gene relative to two housekeeping genes (gyrA and rplL) in batch cultures of three Clostridium perfringens strains with low, intermediate, and high levels of α-toxin production, respectively. The plc....... We propose that this discrepancy is due to differences in plc translation rates between the strains and that strain-specific translational rates therefore must be determined before α-toxin production can be extrapolated from transcript levels in C. perfringens....... transcript level was always low in the low α-toxin producing strain. For the two other strains, plc transcription showed an inducible pattern and reached a maximum level in the late exponential growth phase. The transcription levels were however inversely correlated to α-toxin production for the two strains...

  10. Potentiated Osteoinductivity via Cotransfection with BMP-2 and VEGF Genes in Microencapsulated C2C12 Cells

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    Yang Shen

    2015-01-01

    Full Text Available Microcapsules with entrapped cells hold great promise for repairing bone defects. Unfortunately, the osteoinductivity of microcapsules has been restricted by many factors, among which the deficiency of functional proteins is a significant priority. We potentiated the osteoinductivity of microencapsulated cells via cotransfection with BMP-2 and VEGF genes. Various tissue-derived mesenchymal stem cells and cell lines were compared for BMP-2 and VEGF cotransfection. Ethidium bromide (EB/Calcein AM staining revealed that all of the cell categories could survive for 4 weeks after microencapsulation. An ELISA assay indicated that all microencapsulated BMP-2 or VEGF transfected cells could secrete gene products constitutively for 1 month. Particularly, the recombinant microencapsulated C2C12 cells released the most desirable level of BMP-2 and VEGF. Further experiments demonstrated that microencapsulated BMP-2 and VEGF cotransfected C2C12 cells generated both BMP-2 and VEGF for 4 weeks. Additionally, the cotransfection of BMP-2 and VEGF in microencapsulated C2C12 cells showed a stronger osteogenic induction against BMSCs than individual BMP-2-transfected microencapsulated C2C12 cells. These results demonstrated that the cotransfection of BMP-2 and VEGF into microencapsulated C2C12 cells is of potent utility for the potentiation of bone regeneration, which would provide a promising clinical strategy for cellular therapy in bone defects.

  11. A putative gene cluster from a Lyngbya wollei bloom that encodes paralytic shellfish toxin biosynthesis.

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    Troco K Mihali

    Full Text Available Saxitoxin and its analogs cause the paralytic shellfish-poisoning syndrome, adversely affecting human health and coastal shellfish industries worldwide. Here we report the isolation, sequencing, annotation, and predicted pathway of the saxitoxin biosynthetic gene cluster in the cyanobacterium Lyngbya wollei. The gene cluster spans 36 kb and encodes enzymes for the biosynthesis and export of the toxins. The Lyngbya wollei saxitoxin gene cluster differs from previously identified saxitoxin clusters as it contains genes that are unique to this cluster, whereby the carbamoyltransferase is truncated and replaced by an acyltransferase, explaining the unique toxin profile presented by Lyngbya wollei. These findings will enable the creation of toxin probes, for water monitoring purposes, as well as proof-of-concept for the combinatorial biosynthesis of these natural occurring alkaloids for the production of novel, biologically active compounds.

  12. Detection of Bacillus sphaericus mosquitocidal toxin genes by multiplex colony PCR.

    Science.gov (United States)

    Jagtap, Santosh C; Jagtap, Chandrakant B; Kumar, Pradeep; Srivastava, R B

    2009-02-01

    A multiplex colony PCR assay was developed for the detection of 5 genes encoding Bacillus sphaericus mosquito larvicidal toxins, namely binA, binB, mtx1, mtx2, and mtx3. Primers designed for these 5 genes yielded specific PCR amplicons of the expected size from type cultures of B. sphaericus. This method of detecting multiple toxin genes by colony PCR in a single tube reaction is a simple, rapid, and economical technique for identification of highly toxic environmental B. sphaericus isolates.

  13. New gene targets of PGC-1α and ERRα co-regulation in C2C12 myotubes.

    Science.gov (United States)

    Nsiah-Sefaa, Abena; Brown, Erin L; Russell, Aaron P; Foletta, Victoria C

    2014-12-01

    As a transcriptional coactivator, PGC-1α contributes to the regulation of a broad range of metabolic processes in skeletal muscle health and disease; however, there is limited information about the genes it transcriptionally regulates. To identify new potential gene targets of PGC-1α regulation, mouse C2C12 myotubes were screened by microarray analysis following PGC-1α overexpression. Genes with an mRNA expression of 2.5-fold or more (P genes were singled out if they had no previous connection to PGC-1α regulation or characterization in skeletal muscle, or were unannotated with no known function. Following confirmation of their regulation by PGC-1α using qPCR analysis, eight genes were focused on for further investigation (Akr1b10, Rmnd1, 1110008P14Rik, 1700021F05Rik, Mtfp1, Mrm1, Oxnad1 and Cluh). Bioinformatics indicated a number of the genes were linked to a range of metabolic-related functions including fatty acid oxidation, oxido-reductase activity, and mitochondrial remodeling and transport. Treating C2C12 myotubes for 6 h with AICAR, a known activator of AMP kinase and inducer of Pgc-1α gene expression, increased the mRNA levels of both Pgc-1α (P genes to contain either a consensus or near consensus response elements for the estrogen-related receptor α (ERRα), a key transcription factor-binding partner of PGC-1α in skeletal muscle. Furthermore, knockdown of endogenous ERRα levels partially or completely blocked the induction of gene expression of all genes by PGC-1α, while each gene was significantly upregulated in the presence of a constitutively active form of ERRα (P regulation of these genes by PGC-1α and its signaling pathway in skeletal muscle.

  14. Prevalence of genes for enterotoxins, toxic shock syndrome toxin 1 and exfoliative toxin among clinical isolates of Staphylococcus pseudintermedius from canine origin.

    Science.gov (United States)

    Yoon, Jang W; Lee, Gi-Jong; Lee, So-Young; Park, Chul; Yoo, Jong-Hyun; Park, Hee-Myung

    2010-10-01

    A total of 74 Staphylococcus pseudintermedius strains were isolated from the 99 clinical cases of canine pyoderma or chronic otitis in our veterinary teaching hospital during May 2006-February 2008. In this study, we examined the genetic distribution of staphylococcal pyogenic toxins such as staphylococcal enterotoxins A (sea), B (seb), C (sec), D (sed), E (see), and toxic shock syndrome toxin 1 (tst) as well as the previously characterized S. intermedius exfoliative toxin (siet) among those isolates. The polymerase chain reaction analyses with the toxin gene-specific primers revealed that 18 (24.3%) of 74 S. pseudintermedius isolates carried the sec genes, but none of the sea, seb, sed, see and tst genes. Further DNA sequencing analysis of the amplified sec genes revealed that they all belonged to the canine type C staphylococcal enterotoxin (SEC(canine) ) whose superantigenic activity has been demonstrated. In addition to the sec(canine) genes, our polymerase chain reaction results showed that all the 74 isolates carried the siet gene. Since both SEC(canine) and SIET toxins are known to be biologically active, it would be interesting to investigate how those toxins are involved in the pathogenesis of the canine diseases by S. pseudintermedius such as pyoderma or chronic otitis. © 2010 The Authors. Journal compilation © 2010 ESVD and ACVD.

  15. Woodhouse-Sakati Syndrome: Report of the First Tunisian Family with the C2orf37 Gene Mutation.

    Science.gov (United States)

    Hdiji, Olfa; Turki, Emna; Bouzidi, Nouha; Bouchhima, Imen; Damak, Mariem; Bohlega, Saeed; Mhiri, Chokri

    2016-05-01

    Woodhouse-Sakati syndrome (WSS) is an infrequent autosomal recessive condition characterized by progressive extrapyramidal signs, mental retardation, hypogonadism, alopecia, and diabetes mellitus. This syndrome belongs to a heterogeneous group of inherited neurodegenerative disorders characterized iron accumulation in the brain, and it is caused by mutations of the C2orf37 gene. We report the first Tunisian family with two affected sisters presenting with a phenotype suggestive of WSS. We examined the index patient presenting with movement disorders and mental retardation and then searched for similar cases in her family, which identified a sister with similar signs. We performed a genetic study that confirmed the diagnosis and revealed a c.436delC mutation of the C2orf37 gene. Therefore, WSS is an important consideration in patients presenting with movement disorders and intellectual disability. A high consanguinity contributes to the clustering of such rare autosomal recessive syndromes.

  16. Development of a gene synthesis platform for the efficient large scale production of small genes encoding animal toxins.

    Science.gov (United States)

    Sequeira, Ana Filipa; Brás, Joana L A; Guerreiro, Catarina I P D; Vincentelli, Renaud; Fontes, Carlos M G A

    2016-12-01

    Gene synthesis is becoming an important tool in many fields of recombinant DNA technology, including recombinant protein production. De novo gene synthesis is quickly replacing the classical cloning and mutagenesis procedures and allows generating nucleic acids for which no template is available. In addition, when coupled with efficient gene design algorithms that optimize codon usage, it leads to high levels of recombinant protein expression. Here, we describe the development of an optimized gene synthesis platform that was applied to the large scale production of small genes encoding venom peptides. This improved gene synthesis method uses a PCR-based protocol to assemble synthetic DNA from pools of overlapping oligonucleotides and was developed to synthesise multiples genes simultaneously. This technology incorporates an accurate, automated and cost effective ligation independent cloning step to directly integrate the synthetic genes into an effective Escherichia coli expression vector. The robustness of this technology to generate large libraries of dozens to thousands of synthetic nucleic acids was demonstrated through the parallel and simultaneous synthesis of 96 genes encoding animal toxins. An automated platform was developed for the large-scale synthesis of small genes encoding eukaryotic toxins. Large scale recombinant expression of synthetic genes encoding eukaryotic toxins will allow exploring the extraordinary potency and pharmacological diversity of animal venoms, an increasingly valuable but unexplored source of lead molecules for drug discovery.

  17. Detection of toxin genes and RAPD analysis of bacillus cereus isolates from different soil types

    Directory of Open Access Journals (Sweden)

    Savic Dejana

    2015-01-01

    Full Text Available The aim of this study was to detect genes for enterotoxins (hbla, entFM and bceT and for emetic toxin (cer, to determine antibiotic resistance, and to estimate intraspecies diversity in B. cereus isolates by RAPD analysis. B. cereus was identified in 12 out of 117 indigenous Bacillus spp. using the classical microbiological methods and PCR. All isolates were resistant to penicillin and ampicillin, two to tetracyclin and four to trimethoprim-sulphamethoxazole. Also, all isolates produced inducible penicillinases and β-lactamase. Toxin genes were detected with PCR. EntFM and cer genes were present in all isolates, hbla in all, but two, and bceT in none. RAPD analysis was performed with four different primers, two of them designed for this study. The intraspecies diversity revealed 10 different patterns at the 90% similarity level. Two separate clusters were formed regardless of a soil type or utilization. The detection of genes encoding toxins in all B. cereus isolates indicated these bacteria as potentially pathogenic and seriously for human health. Regardless of a soil type or utilization, the RAPD analysis showed high intraspecies heterogeneity in B. cereus isolates. To the best of our knowledge, this is the first study to analyse the presence of entero- and emetic toxin genes and genetic heterogeneity in B. cereus isolates from different soil types and different soil utilization in Serbia. [Projekat Ministarstva nauke Republike Srbije, br. TR37006

  18. Molecular phylogeny of OVOL genes illustrates a conserved C2H2 zinc finger domain coupled by hypervariable unstructured regions.

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    Abhishek Kumar

    Full Text Available OVO-like proteins (OVOL are members of the zinc finger protein family and serve as transcription factors to regulate gene expression in various differentiation processes. Recent studies have shown that OVOL genes are involved in epithelial development and differentiation in a wide variety of organisms; yet there is a lack of comprehensive studies that describe OVOL proteins from an evolutionary perspective. Using comparative genomic analysis, we traced three different OVOL genes (OVOL1-3 in vertebrates. One gene, OVOL3, was duplicated during a whole-genome-duplication event in fish, but only the copy (OVOL3b was retained. From early-branching metazoa to humans, we found that a core domain, comprising a tetrad of C2H2 zinc fingers, is conserved. By domain comparison of the OVOL proteins, we found that they evolved in different metazoan lineages by attaching intrinsically-disordered (ID segments of N/C-terminal extensions of 100 to 1000 amino acids to this conserved core. These ID regions originated independently across different animal lineages giving rise to different types of OVOL genes over the course of metazoan evolution. We illustrated the molecular evolution of metazoan OVOL genes over a period of 700 million years (MY. This study both extends our current understanding of the structure/function relationship of metazoan OVOL genes, and assembles a good platform for further characterization of OVOL genes from diverged organisms.

  19. Rapid detection of vip1-type genes from Bacillus cereus and characterization of a novel vip binary toxin gene.

    Science.gov (United States)

    Yu, Xiumei; Liu, Tao; Liang, Xiaoxing; Tang, Changqing; Zhu, Jun; Wang, Shiquan; Li, Shuangcheng; Deng, Qiming; Wang, Linxia; Zheng, Aiping; Li, Ping

    2011-12-01

    A PCR-restriction fragment length polymorphism (PCR-RFLP) method for identifying vegetative insecticidal protein (vip) 1-type genes from Bacillus cereus was developed by designing specific primers based on the conserved regions of the genes to amplify vip1-type gene fragments. PCR products were digested with endonuclease AciI, and four known vip1-type genes were identified. Vip1Ac and vip1Aa-type genes appeared in 17 of 26 B. cereus strains. A novel vip1-type gene, vip1Ac1, was identified from B. cereus strain HL12. The vip1Ac1 and vip2Ae3 genes were co-expressed in Escherichia coli strain BL21 by vector pCOLADuet-1. The binary toxin showed activity only against Aphis gossypii (Homoptera), but not for Coleptera (Tenebrio molitor, Holotrichia oblita), Lepidoptera (Spodoptera exigua, Helicoverpa armigera, and Chilo suppressalis), Diptera (Culex quinquefasciatus). The LC(50) of this binary toxin for A. gossypii is 87.5 (34.2-145.3) ng mL(-1) . This is probably only the second report that Vip1 and Vip2 binary toxin shows toxicity against homopteran pests. The PCR-RFLP method developed could be very useful for identifying novel Vip1-Vip2-type binary toxins, and the novel binary toxins, Vip1Ac1 and Vip2Ae3, identified in this study may have applications in biological control of insects, thus avoiding potential problems of resistance. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  20. A survey of well conserved families of C2H2 zinc-finger genes in Daphnia

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    Bai Yang

    2010-04-01

    Full Text Available Abstract Background A recent comparative genomic analysis tentatively identified roughly 40 orthologous groups of C2H2 Zinc-finger proteins that are well conserved in "bilaterians" (i.e. worms, flies, and humans. Here we extend that analysis to include a second arthropod genome from the crustacean, Daphnia pulex. Results Most of the 40 orthologous groups of C2H2 zinc-finger proteins are represented by just one or two proteins within each of the previously surveyed species. Likewise, Daphnia were found to possess a similar number of orthologs for all of these small orthology groups. In contrast, the number of Sp/KLF homologs tends to be greater and to vary between species. Like the corresponding mammalian Sp/KLF proteins, most of the Drosophila and Daphnia homologs can be placed into one of three sub-groups: Class I-III. Daphnia were found to have three Class I proteins that roughly correspond to their Drosophila counterparts, dSP1, btd, CG5669, and three Class II proteins that roughly correspond to Luna, CG12029, CG9895. However, Daphnia have four additional KLF-Class II proteins that are most similar to the vertebrate KLF1/2/4 proteins, a subset not found in Drosophila. Two of these four proteins are encoded by genes linked in tandem. Daphnia also have three KLF-Class III members, one more than Drosophila. One of these is a likely Bteb2 homolog, while the other two correspond to Cabot and KLF13, a vertebrate homolog of Cabot. Conclusion Consistent with their likely roles as fundamental determinants of bilaterian form and function, most of the 40 groups of C2H2 zinc-finger proteins are conserved in kind and number in Daphnia. However, the KLF family includes several additional genes that are most similar to genes present in vertebrates but missing in Drosophila.

  1. Isolation of Clostridium difficile and Detection of A and B Toxins Encoding Genes

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    Abbas Ali Imani Fooladi

    2014-02-01

    Full Text Available Background: Clostridium difficile is the most important anaerobic, gram positive, spore forming bacillus which is known as a prevalent factor leading to antibiotic associated diarrheas and is the causative agent of pseudomembrane colitis. The role of this bacterium along with the over use of antibiotics have been proved to result in colitis. The major virulence factors of these bacteria are the A and B toxins. Objectives: The purpose of this study was to isolate C. difficile from stool samples and detect A and B toxins encoding genes, in order toserve as a routine method for clinical diagnosis. Materials and Methods: Recognition of A and B toxins encoding genes by uniplex and multiplex PCR using two pairs of primers from 136 accumulated stool samples. Results: Results of the present study showed that out of 136 stool samples, three C. difficile were isolated and these strains contained A and B toxins encoding genes. Conclusions: It was concluded that although detection of C. difficile from stool samples based on PCR (polymerase chain reaction is expensive, yet this method is more sensitive and less time-consuming than culture methods and can be used as a clinical laboratory test.

  2. Gene expression profiles and molecular mechanism of cultured human chondrocytes' exposure to T-2 toxin and deoxynivalenol.

    Science.gov (United States)

    Yang, Lei; Zhang, Jianping; Zhao, Guanghui; Wu, Cuiyan; Ning, Yujie; Wang, Xi; Lammi, Mikko J; Guo, Xiong

    2017-12-15

    T-2 toxin and deoxynivalenol (DON) are secondary metabolites produced by Fusarium fungi and are commonly found on food and feed. Although T-2 toxin and DON have been suggested as the etiology of Kashin-Beck disease (KBD), an endemic osteochondropathy, little is known about the mechanism when human chondrocytes are exposed to T-2 toxin and DON. The purpose of this study is to identify the gene expression differences and underlying molecular changes modulated by T-2 toxin and DON in vitro in human chondrocytes. After the experiments of cell viability, the gene expression profiles were analyzed in cells that were treated with 0.01 μg/ml T-2 toxin and 1.0 μg/ml DON for 72 h by Affymetrix Human Gene Chip. The array results showed that 882 and 2118 genes were differentially expressed for T-2 toxin and DON exposure, respectively. Enrichment analysis revealed that diverse cellular processes including DNA damage, cell cycle regulation and metabolism of extracellular matrix were affected when human chondrocytes were exposed to T-2 toxin and DON. These results demonstrate the gene expression differences and molecular mechanism of cultured human chondrocytes exposure to T-2 toxin and DON, and provide a new insight into future research in the etiology of KBD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Genes and evolution of two-domain toxins from lynx spider venom.

    Science.gov (United States)

    Sachkova, Maria Y; Slavokhotova, Anna A; Grishin, Eugene V; Vassilevski, Alexander A

    2014-03-03

    Spiderines are comparatively long polypeptide toxins (∼110 residues) from lynx spiders (genus Oxyopes). They are built of an N-terminal linear cationic domain (∼40 residues) and a C-terminal knottin domain (∼60 residues). The linear domain empowers spiderines with strong cytolytic activity. In the present work we report 16 novel spiderine sequences from Oxyopes takobius and Oxyopes lineatus classified into two subfamilies. Strikingly, negative selection acts on both linear and knottin domains. Genes encoding Oxyopes two-domain toxins were sequenced and found to be intronless. We further discuss a possible scenario of lynx spider modular toxin evolution. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  4. Detection of seven virulence and toxin genes of Campylobacter jejuni isolates from Danish turkeys by PCR and cytolethal distending toxin production of the isolates

    DEFF Research Database (Denmark)

    Bang, Dang Duong; Borck, Birgitte; Nielsen, Eva Møller

    2004-01-01

    A total of 117 Campylobacter jejuni isolates from Danish turkeys were tested for the presence of seven virulence and toxin genes by PCR. One hundred seventeen (100%) isolates were positive for flaA, cadF, and ceuE gene primers. One hundred three (88%) isolates were positive for cdt gene cluster P...... turkeys and calls for further investigation for the elimination of Campylobacter infection in industrial turkey production and in industrial food chains.......A total of 117 Campylobacter jejuni isolates from Danish turkeys were tested for the presence of seven virulence and toxin genes by PCR. One hundred seventeen (100%) isolates were positive for flaA, cadF, and ceuE gene primers. One hundred three (88%) isolates were positive for cdt gene cluster PCR...

  5. Identification of toxin genes encoding Cyt proteins from standard ...

    African Journals Online (AJOL)

    Polymerase chain reaction-restriction fragment length polymorphism methods for identification of cyt subclasses from Bacillus thuringiensis were established. Eight of 68 standard and ten of 107 Argentine B. thuringiensis strains harbor at least one cyt gene. The combination of cyt1Aa/cyt2Ba genes was identified in four ...

  6. PREVALENCE OF TOXIN ENCODING GENES IN ESCHERICHIACOLI ISOLATES FROM URINARY TRACT INFECTIONS INSLOVENIA

    Directory of Open Access Journals (Sweden)

    Marjanca Starčič-Erjavec

    2008-06-01

    Full Text Available Methods 110 uropathogenic Escherichia coli strains (UPEC obtained from the Institute of Microbiology and Immunology of the Medical Faculty in Ljubljana were screened by PCR withprimers specific for the following toxin encoding genes: hlyA (haemolysin, cnf1 (cytotoxicnecrotising factor 1, usp (uropathogenic specific protein USP and ibeA (invasin. Dotblot hybridisation experiments were performed to validate the PCR assays.Results In 44% of the strains usp gene sequences were detected. The prevalence of hlyA and cnf1was 25% and 23%, respectively. Only 9% of the strains harbored ibeA. The majority of thetested toxin encoding genes was found in strains belonging to the B2 phylogenetic group.Conclusions The toxin encoding genes hlyA, cnf1 and usp were strongly co-associated. Further, we founda statistically significant co-association of ibeA and usp. The prevalence of the testedtoxin encoding genes in E. coli strains from urinary tract infections isolated in Slovenia iscomparable to those from studies in other geographic regions.

  7. Bacteriophage-encoded shiga toxin gene in atypical bacterial host

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    Casas Veronica

    2011-07-01

    Full Text Available Abstract Background Contamination from fecal bacteria in recreational waters is a major health concern since bacteria capable of causing human disease can be found in animal feces. The Dog Beach area of Ocean Beach in San Diego, California is a beach prone to closures due to high levels of fecal indicator bacteria (FIB. A potential source of these FIB could be the canine feces left behind by owners who do not clean up after their pets. We tested this hypothesis by screening the DNA isolated from canine feces for the bacteriophage-encoded stx gene normally found in the virulent strains of the fecal bacterium Escherichia coli. Results Twenty canine fecal samples were collected, processed for total and bacterial fraction DNA, and screened by PCR for the stx gene. The stx gene was detected in the total and bacterial fraction DNA of one fecal sample. Bacterial isolates were then cultivated from the stx-positive fecal sample. Eighty nine of these canine fecal bacterial isolates were screened by PCR for the stx gene. The stx gene was detected in five of these isolates. Sequencing and phylogenetic analyses of 16S rRNA gene PCR products from the canine fecal bacterial isolates indicated that they were Enterococcus and not E. coli. Conclusions The bacteriophage-encoded stx gene was found in multiple species of bacteria cultivated from canine fecal samples gathered at the shoreline of the Dog Beach area of Ocean Beach in San Diego, California. The canine fecal bacteria carrying the stx gene were not the typical E. coli host and were instead identified through phylogenetic analyses as Enterococcus. This suggests a large degree of horizontal gene transfer of exotoxin genes in recreational waters.

  8. Detection of the beta2 toxin gene of Clostridium perfringens in diarrhoeic piglets in The Netherlands and Switzerland.

    Science.gov (United States)

    Klaasen, H L; Molkenboer, M J; Bakker, J; Miserez, R; Häni, H; Frey, J; Popoff, M R; van den Bosch, J F

    1999-07-01

    The two studies presented here were done to determine the prevalence of the alpha, beta, epsilon and enterotoxin genes and the novel beta2 toxin gene of Clostridium perfringens in neonatal or pre-weaned piglets with diarrhoea or necrotic enteritis. All C. perfringens isolates were positive for the alpha and negative for the epsilon and enterotoxin gene, implying that only non-enterotoxigenic type A and C strains were detected. The most important findings were the relatively high prevalence of the beta2 toxin gene in isolates from diarrhoeic piglets in both studies, and, in one of the two studies, absence of strains with only the alpha and beta toxin gene. These data are supportive for the suggestion of a causal relationship of beta2 toxin-producing strains with digestive tract diseases in piglets.

  9. Expressional studies of the aldehyde oxidase (AOX1) gene during myogenic differentiation in C2C12 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kamli, Majid Rasool; Kim, Jihoe; Pokharel, Smritee; Jan, Arif Tasleem [School of Biotechnology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Lee, Eun Ju [School of Biotechnology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Bovine Genome Resources Bank, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Choi, Inho, E-mail: inhochoi@ynu.ac.kr [School of Biotechnology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Bovine Genome Resources Bank, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)

    2014-08-08

    Highlights: • AOX1 contributes to the formation of myotube. • Silencing of AOX1 reduces myotube formation. • AOX1 regulates MyoG gene expression. • AOX1 contributes to myogenesis via H{sub 2}O{sub 2}. - Abstract: Aldehyde oxidases (AOXs), which catalyze the hydroxylation of heterocycles and oxidation of a wide variety of aldehydic compounds, have been present throughout evolution from bacteria to humans. While humans have only a single functional aldehyde oxidase (AOX1) gene, rodents are endowed with four AOXs; AOX1 and three aldehyde oxidase homologs (AOH1, AOH2 and AOH3). In continuation of our previous study conducted to identify genes differentially expressed during myogenesis using a microarray approach, we investigated AOX1 with respect to its role in myogenesis to conceptualize how it is regulated in C2C12 cells. The results obtained were validated by silencing of the AOX1 gene. Analysis of their fusion index revealed that formation of myotubes showed a marked reduction of up to 40% in AOX1{sub kd} cells. Expression of myogenin (MYOG), one of the marker genes used to study myogenesis, was also found to be reduced in AOX1{sub kd} cells. AOX1 is an enzyme of pharmacological and toxicological importance that metabolizes numerous xenobiotics to their respective carboxylic acids. Hydrogen peroxide (H{sub 2}O{sub 2}) produced as a by-product in this reaction is considered to be involved as a part of the signaling mechanism during differentiation. An observed reduction in the level of H{sub 2}O{sub 2} among AOX1{sub kd} cells confirmed production of H{sub 2}O{sub 2} in the reaction catalyzed by AOX1. Taken together, these findings suggest that AOX1 acts as a contributor to the process of myogenesis by influencing the level of H{sub 2}O{sub 2}.

  10. Docosahexaenoyl ethanolamide improves glucose uptake and alters endocannabinoid system gene expression in proliferating and differentiating C2C12 myoblasts

    Directory of Open Access Journals (Sweden)

    Jeffrey eKim

    2014-03-01

    Full Text Available Skeletal muscle is a major storage site for glycogen and a focus for understanding insulin resistance and type-2-diabetes. New evidence indicates that overactivation of the peripheral endocannabinoid system (ECS in skeletal muscle diminishes insulin sensitivity. Specific n-6 and n-3 polyunsaturated fatty acids (PUFA are precursors for the biosynthesis of ligands that bind to and activate the cannabinoid receptors. The function of the ECS and action of PUFA in skeletal muscle glucose uptake was investigated in proliferating and differentiated C2C12 myoblasts treated with either 25µM of arachidonate (AA or docosahexaenoate (DHA, 25µM of EC [anandamide (AEA, 2-arachidonoylglycerol (2-AG, docosahexaenoylethanolamide (DHEA], 1µM of CB1 antagonist NESS0327, and CB2 antagonist AM630. Compared to the BSA vehicle control cell cultures in both proliferating and differentiated myoblasts those treated with DHEA, the EC derived from the n-3 PUFA DHA, had higher 24 h glucose uptake, while AEA and 2-AG, the EC derived from the n-6 PUFA AA, had lower basal glucose uptake. Adenylyl cyclase mRNA was higher in myoblasts treated with DHA in both proliferating and differentiated states while those treated with AEA or 2-AG were lower compared to the control cell cultures. Western blot and qPCR analysis showed higher expression of the cannabinoid receptors in differentiated myoblasts treated with DHA while the opposite was observed with AA. These findings indicate a compensatory effect of DHA and DHEA compared to AA-derived ligands on the ECS and associated ECS gene expression and higher glucose uptake in myoblasts.Key Words: endocannabinoid system •C2C12 myoblasts cannabinoid receptors glucose uptake gene expression DHEA • polyunsaturated fatty acids

  11. Detection of toxic shock toxin (tst gene in Staphylococcus aureus isolated from bovine milk samples

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    S. Baniardalan

    2017-09-01

    Full Text Available Staphylococcus aureus is a major causative pathogen of clinical and subclinical mastitis in dairy cattle all over the world. This agent produces a variety of extracellular toxins and virulence factors in-cluding toxic shock syndrome toxin-1 (TSST-1 which is the major cause of toxic shock syndrome (TSS. In the present study, 76 S. aureus isolates have been obtained from milk samples collected from 7 dairy herds in Hamedan province of Iran. The isolates were identified based on the biochemical and molecular methods using PCR amplification of the femA gene. The staphylococcal isolates were also examined for the presence of TSST-1 (tst encoding gene. This gene was detected in only one S. aureus isolate (1.3%. The results revealed that S. aureus strains causing bovine mastitis may potentially produce staphylococcal toxic shock syndrome toxin-1, indicating that it is very important to follow the presence of TSST-1 producing S. aureus isolates in foodstuffs to protect consumers against the risk of toxic shock syndrome

  12. Gene family encoding the major toxins of lethal Amanita mushrooms

    Science.gov (United States)

    Hallen, Heather E.; Luo, Hong; Scott-Craig, John S.; Walton, Jonathan D.

    2007-01-01

    Amatoxins, the lethal constituents of poisonous mushrooms in the genus Amanita, are bicyclic octapeptides. Two genes in A. bisporigera, AMA1 and PHA1, directly encode α-amanitin, an amatoxin, and the related bicyclic heptapeptide phallacidin, a phallotoxin, indicating that these compounds are synthesized on ribosomes and not by nonribosomal peptide synthetases. α-Amanitin and phallacidin are synthesized as proproteins of 35 and 34 amino acids, respectively, from which they are predicted to be cleaved by a prolyl oligopeptidase. AMA1 and PHA1 are present in other toxic species of Amanita section Phalloidae but are absent from nontoxic species in other sections. The genomes of A. bisporigera and A. phalloides contain multiple sequences related to AMA1 and PHA1. The predicted protein products of this family of genes are characterized by a hypervariable “toxin” region capable of encoding a wide variety of peptides of 7–10 amino acids flanked by conserved sequences. Our results suggest that these fungi have a broad capacity to synthesize cyclic peptides on ribosomes. PMID:18025465

  13. Characterization of Clostridium perfringens TpeL Toxin Gene Carriage, Production, Cytotoxic Contributions, and Trypsin Sensitivity

    Science.gov (United States)

    Chen, Jianming

    2015-01-01

    Large clostridial toxins (LCTs) are produced by at least four pathogenic clostridial species, and several LCTs are proven pivotal virulence factors for both human and veterinary diseases. TpeL is a recently identified LCT produced by Clostridium perfringens that has received relatively limited study. In response, the current study surveyed carriage of the tpeL gene among different C. perfringens strains, detecting this toxin gene in some type A, B, and C strains but not in any type D or E strains. This study also determined that all tested strains maximally produce, and extracellularly release, TpeL at the late-log or early-stationary growth stage during in vitro culture, which is different from the maximal late-stationary-phase production reported previously for other LCTs and for TpeL production by C. perfringens strain JIR12688. In addition, the present study found that TpeL levels in culture supernatants can be repressed by either glucose or sucrose. It was also shown that, at natural production levels, TpeL is a significant contributor to the cytotoxic activity of supernatants from cultures of tpeL-positive strain CN3685. Lastly, this study identified TpeL, which presumably is produced in the intestines during diseases caused by TpeL-positive type B and C strains, as a toxin whose cytotoxicity decreases after treatment with trypsin; this finding may have pathophysiologic relevance by suggesting that, like beta toxin, TpeL contributes to type B and C infections in hosts with decreased trypsin levels due to disease, diet, or age. PMID:25824828

  14. Quantitative Detection of Clostridium perfringens in Broiler Chickens by Real-Time PCR Targeting the Alpha-Toxin Gene

    DEFF Research Database (Denmark)

    Abildgaard, Lone; Engberg, Ricarda M.; Schramm, Andreas

    2006-01-01

    QUANTITATIVE DETECTION OF CLOSTRIDIUM PERFRINGENS IN BROILER CHICKENS BY REAL-TIME PCR TARGETING THE ALPHA-TOXIN GENE L. Abildgaard 1, R.M. Engberg 1, A. Schramm 2, O. Højberg 1 1 Danish Institute of Agricultural Sciences, Department of Animal Health, Welfare and Nutrition, Tjele, Denmark; 2...... University of Aarhus, Institute of Biological Sciences, Department of Microbiology, Aarhus, Denmark Necrotic enteritis is a severe gastrointestinal disease in broiler chickens caused by C. perfringens producing α-toxin (phospholipase C). The incidence of necrotic enteritis in broilers has been reduced...... by antibiotics (ionophores) presently used to prevent parasitic coccidiosis. From 2012 the European Union has banned these anticoccidials as feed additives, wherefore alternatives are needed to suppress C. perfringens and/or α-toxin production. A real-time PCR primer-probe set targeting the α-toxin gene...

  15. Sequence variation in the alpha-toxin encoding plc gene of Clostridium perfringens strains isolated from diseased and healthy chickens

    DEFF Research Database (Denmark)

    Abildgaard, L; Engberg, RM; Pedersen, Karl

    2009-01-01

    The aim of the present study was to analyse the genetic diversity of the alpha-toxin encoding plc gene and the variation in a-toxin production of Clostridium perfringens type A strains isolated from presumably healthy chickens and chickens suffering from either necrotic enteritis (NE) or cholangio......-hepatitis. The a-toxin encoding plc genes from 60 different pulsed-field gel electrophoresis (PFGE) types (strains) of C perfringens were sequenced and translated in silico to amino acid sequences and the a-toxin production was investigated in batch cultures of 45 of the strains using an enzyme......-linked immunosorbent assay (ELISA) approach. Overall, the truncated amino acid sequences showed close similarity (> 98% at the amino acid level) to previously reported sequences from chicken-derived C. perfringens isolates. Variations were however observed in 23 out of 379 aa positions leading to the definition of 26...

  16. Transfer of the toxin protein genes of Bacillus sphaericus into Bacillus thuringiensis subsp. israelensis and their expression.

    OpenAIRE

    Bourgouin, C.; Delécluse, A; LA TORRE, F.; Szulmajster, J

    1990-01-01

    The genes encoding the toxic determinants of Bacillus sphaericus have been expressed in a nontoxic and a toxic strain of Bacillus thuringiensis subsp. israelensis. In both cases, the B. sphaericus toxin proteins were produced at a high level during sporulation of B. thuringiensis and accumulated as crystalline structures. B. thuringiensis transformants expressing B. sphaericus and B. thuringiensis subsp. israelensis toxins did not show a significant enhancement of toxicity against Aedes aegyp...

  17. Venom gland transcriptomes of two elapid snakes (Bungarus multicinctus and Naja atra) and evolution of toxin genes

    Science.gov (United States)

    2011-01-01

    Background Kraits (genus Bungarus) and cobras (genus Naja) are two representative toxic genera of elapids in the old world. Although they are closely related genera and both of their venoms are very toxic, the compositions of their venoms are very different. To unveil their detailed venoms and their evolutionary patterns, we constructed venom gland cDNA libraries and genomic bacterial artificial chromosome (BAC) libraries for Bungarus multicinctus and Naja atra, respectively. We sequenced about 1500 cDNA clones for each of the venom cDNA libraries and screened BAC libraries of the two snakes by blot analysis using four kinds of toxin probes; i.e., three-finger toxin (3FTx), phospholipase A2 (PLA2), kunitz-type protease inhibitor (Kunitz), and natriuretic peptide (NP). Results In total, 1092 valid expressed sequences tags (ESTs) for B. multicinctus and 1166 ESTs for N. atra were generated. About 70% of these ESTs can be annotated as snake toxin transcripts. 3FTx (64.5%) and β bungarotoxin (25.1%) comprise the main toxin classes in B. multicinctus, while 3FTx (95.8%) is the dominant toxin in N. atra. We also observed several less abundant venom families in B. multicinctus and N. atra, such as PLA2, C-type lectins, and Kunitz. Peculiarly a cluster of NP precursors with tandem NPs was detected in B. multicinctus. A total of 71 positive toxin BAC clones in B. multicinctus and N. atra were identified using four kinds of toxin probes (3FTx, PLA2, Kunitz, and NP), among which 39 3FTx-postive BACs were sequenced to reveal gene structures of 3FTx toxin genes. Conclusions Based on the toxin ESTs and 3FTx gene sequences, the major components of B. multicinctus venom transcriptome are neurotoxins, including long chain alpha neurotoxins (α-ntx) and the recently originated β bungarotoxin, whereas the N. atra venom transcriptome mainly contains 3FTxs with cytotoxicity and neurotoxicity (short chain α-ntx). The data also revealed that tandem duplications contributed the most to

  18. Detection of methicillin resistant and toxin-associated genes in Staphylococcus aureus

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    Cajethan Ezeamagu

    2018-03-01

    Full Text Available Methicillin-resistant Staphylococcus aureus is a problem in both healthcare institutions and community settings. This is due to its multi-drug resistant challenges. Hence, this study assessed the prevalence of methicillin resistant gene (mecA, exfoliative toxin (eta and etb and toxic shock syndrome (tsst-1 genes in S. aureus isolated from clinical samples. A total of 120 clinical samples of patients (urine, high vagina swab (HVS, semen, wound swab, sputum and urethral swab from a hospital laboratory were obtained. S. aureus was isolated and then identified with API-staph kit. Antibiotic susceptibility of the isolates was determined by agar diffusion while PCR was used to detect the presence of mecA and toxin-associated genes. Fifty S. aureus isolates were obtained at frequencies of 26(52%, 12(24%, 4(8%, 3(6%, 3(6% and 2(4% from the HVS, urine, semen, wound, sputum and urethral swab samples respectively. All the isolates of S. aureus were resistant to the antibiotics used in this study. MecA, tsst-1, eta and etb were detected in 19(38%, 7(14%, 3(6% and 2(4% of the isolates respectively. The prevalence of MRSA and its resistance pattern observed in this study was a signal that the health-care workers and the general public are at risk.

  19. Identification of shiga toxin and intimin genes in Escherichia coli detected from canary (Serinus canaria domestica).

    Science.gov (United States)

    Gholami-Ahangaran, Majid; Zia-Jahromi, Noosha

    2014-09-01

    The pathogenicity of enterohemorrhagic Escherichia coli (EHEC) strains is, in large part, due to shiga toxin (Stx) genes (Stx1 and Stx2) and/or intimin (eae) gene. The purpose of this study was to analyze the role of domestic canaries (Serinus canaria domestica) as a reservoir of Stx and intimin producing strains of E. coli. For this study, a total of 50 cloacal swabs were collected from 50 healthy domestic canaries. Cloacal swabs were cultured and tested using standard methods of microbiology. After primary identification of E. coli, DNA was extracted and polymerase chain reaction was performed using specific primers for Stx1, Stx2 and eae genes. In this study, three of 50 samples were found to be Stx2 positive. In the present study, nine (18%) of 50 canaries tested were positive for eae gene. Only 2% of total canaries tested were positive for simultaneous Stx and eae genes. By considering the presence of Stx genes in E. coli isolated from cloacal contents of canary, this hypothesis expressed that the canaries may be the carriers of virulence genes that can risk human health. Canary was considered to be a reservoir of Stx and intimin genes and make these birds important vehicles for the spread of zoonosis infection. © The Author(s) 2012.

  20. Exogenous C2 Ceramide Suppresses Matrix Metalloproteinase Gene Expression by Inhibiting ROS Production and MAPK Signaling Pathways in PMA-Stimulated Human Astroglioma Cells

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    Ji-Sun Jung

    2016-03-01

    Full Text Available Matrix metalloproteinases (MMPs are a family of zinc-dependent endopeptidases, which play a pivotal role in invasion, migration, and angiogenesis of glioma. Therefore, controlling MMPs is potentially an important therapeutic strategy for glioma. In the present study, we found that exogenous cell-permeable short-chain C2 ceramide inhibits phorbol myristate acetate (PMA-induced MMP-1, -3, and -9 gene expressions in U87MG and U373MG human astroglioma cells. In addition, C2 ceramide inhibited the protein secretion and enzymatic activities of MMP-1, -3, and -9. The Matrigel invasion assay and wound healing assay showed that C2 ceramide suppresses the in vitro invasion and migration of glioma cells, which appears to be involved in strong inhibition of MMPs by C2 ceramide. Subsequent mechanistic studies revealed that C2 ceramide inhibits PMA-induced mitogen-activated protein kinase (MAPK phosphorylation and nuclear factor (NF-κB/activator protein (AP-1 DNA binding activities. Furthermore, C2 ceramide significantly inhibited PMA-induced reactive oxygen species (ROS production and NADPH oxidase 4 (NOX4 expression, and inhibition of ROS by diphenylene iodonium (DPI, NADPH oxidase inhibitor mimicked the effects of C2 ceramide on MMP expression and NF-κB/AP-1 via inhibition of p38 MAPK. The results suggest C2 ceramide inhibits MMP expression and glioma invasion, at least partly, by modulating ROS-p38 MAPK signaling axis and other MAPK signaling pathways.

  1. SxtA and sxtG Gene Expression and Toxin Production in the Mediterranean Alexandrium minutum (Dinophyceae

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    Federico Perini

    2014-10-01

    Full Text Available The dinoflagellate Alexandrium minutum is known for the production of potent neurotoxins affecting the health of human seafood consumers via paralytic shellfish poisoning (PSP. The aim of this study was to investigate the relationship between the toxin content and the expression level of the genes involved in paralytic shellfish toxin (PST production. The algal cultures were grown both in standard f/2 medium and in phosphorus/nitrogen limitation. In our study, LC-HRMS analyses of PST profile and content in different Mediterranean A. minutum strains confirmed that this species was able to synthesize mainly the saxitoxin analogues Gonyautoxin-1 (GTX1 and Gonyautoxin-4 (GTX4. The average cellular toxin content varied among different strains, and between growth phases, highlighting a decreasing trend from exponential to stationary phase in all culture conditions tested. The absolute quantities of intracellular sxtA1 and sxtG mRNA were not correlated with the amount of intracellular toxins in the analysed A. minutum suggesting that the production of toxins may be regulated by post-transcriptional mechanisms and/or by the concerted actions of alternative genes belonging to the PST biosynthesis gene cluster. Therefore, it is likely that the sxtA1 and sxtG gene expression could not reflect the PST accumulation in the Mediterranean A. minutum populations under the examined standard and nutrient limiting conditions.

  2. Expression of mosquito active toxin genes by a Colombian native strain of the gram-negative bacterium Asticcacaulis excentricus

    Directory of Open Access Journals (Sweden)

    Romero Magally

    2001-01-01

    Full Text Available Mosquito control with biological insecticides, such as Bacillus sp. toxins, has been used widely in many countries. However, rapid sedimentation away from the mosquito larvae feeding zone causes a low residual effect. In order to overcome this problem, it has been proposed to clone the Bacillus toxin genes in aquatic bacteria which are able to live in the upper part of the water column. Two strains of Asticcacaulis excentricus were chosen to introduce the B. sphaericus binary toxin gene and B. thuringiensis subsp. medellin cry11Bb gene cloned in suitable vectors. In feeding experiments with these aquatic bacteria, it was shown that Culex quinquefasciatus, Aedes aegypti, and Anopheles albimanus larvae were able to survive on a diet based on this wild bacterium. A. excentricus recombinant strains were able to express both genes, but the recombinant strain expressing the B. sphaericus binary toxin was toxic to mosquito larvae. Crude protease A. excentricus extracts did not degrade the Cry11Bb toxin. The flotability studies indicated that the recombinant A. excentricus strains remained in the upper part of the water column longer than the wild type Bacillus strains.

  3. The essential function of B. subtilis RNase III is to silence foreign toxin genes.

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    Sylvain Durand

    Full Text Available RNase III-related enzymes play key roles in cleaving double-stranded RNA in many biological systems. Among the best-known are RNase III itself, involved in ribosomal RNA maturation and mRNA turnover in bacteria, and Drosha and Dicer, which play critical roles in the production of micro (mi-RNAs and small interfering (si-RNAs in eukaryotes. Although RNase III has important cellular functions in bacteria, its gene is generally not essential, with the remarkable exception of that of Bacillus subtilis. Here we show that the essential role of RNase III in this organism is to protect it from the expression of toxin genes borne by two prophages, Skin and SPβ, through antisense RNA. Thus, while a growing number of organisms that use RNase III or its homologs as part of a viral defense mechanism, B. subtilis requires RNase III for viral accommodation to the point where the presence of the enzyme is essential for cell survival. We identify txpA and yonT as the two toxin-encoding mRNAs of Skin and SPβ that are sensitive to RNase III. We further explore the mechanism of RNase III-mediated decay of the txpA mRNA when paired to its antisense RNA RatA, both in vivo and in vitro.

  4. Transfer of toxin genes to alternate bacterial hosts for mosquito control

    Directory of Open Access Journals (Sweden)

    Sergio Orduz

    1995-02-01

    Full Text Available Mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. The use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. Bacillus thuringiensis and B. sphaericus produce toxic proteins to mosquito larvae. Great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding them. Nevertheless, the low residuality of these biological insecticides is one of the major drawbacks. This article present some interesting aspects of the mosquito larvae feeding habits and review the attempts that have been made to genetically engineer microorganisms that while are used by mosquito larvae as a food source should express the Bacillus toxin genes in order to improve the residuality and stability in the mosquito breeding ponds.

  5. Comparative analyses of putative toxin gene homologs from an Old World viper, Daboia russelii

    Directory of Open Access Journals (Sweden)

    Neeraja M. Krishnan

    2017-12-01

    Full Text Available Availability of snake genome sequences has opened up exciting areas of research on comparative genomics and gene diversity. One of the challenges in studying snake genomes is the acquisition of biological material from live animals, especially from the venomous ones, making the process cumbersome and time-consuming. Here, we report comparative sequence analyses of putative toxin gene homologs from Russell’s viper (Daboia russelii using whole-genome sequencing data obtained from shed skin. When compared with the major venom proteins in Russell’s viper studied previously, we found 45–100% sequence similarity between the venom proteins and their putative homologs in the skin. Additionally, comparative analyses of 20 putative toxin gene family homologs provided evidence of unique sequence motifs in nerve growth factor (NGF, platelet derived growth factor (PDGF, Kunitz/Bovine pancreatic trypsin inhibitor (Kunitz BPTI, cysteine-rich secretory proteins, antigen 5, andpathogenesis-related1 proteins (CAP and cysteine-rich secretory protein (CRISP. In those derived proteins, we identified V11 and T35 in the NGF domain; F23 and A29 in the PDGF domain; N69, K2 and A5 in the CAP domain; and Q17 in the CRISP domain to be responsible for differences in the largest pockets across the protein domain structures in crotalines, viperines and elapids from the in silico structure-based analysis. Similarly, residues F10, Y11 and E20 appear to play an important role in the protein structures across the kunitz protein domain of viperids and elapids. Our study highlights the usefulness of shed skin in obtaining good quality high-molecular weight DNA for comparative genomic studies, and provides evidence towards the unique features and evolution of putative venom gene homologs in vipers.

  6. Unusual accelerated rate of deletions and insertions in toxin genes in the venom glands of the pygmy copperhead (Austrelaps labialis) from Kangaroo island.

    Science.gov (United States)

    Doley, Robin; Tram, Nguyen Ngoc Bao; Reza, Md Abu; Kini, R Manjunatha

    2008-02-28

    Toxin profiling helps in cataloguing the toxin present in the venom as well as in searching for novel toxins. The former helps in understanding potential pharmacological profile of the venom and evolution of toxins, while the latter contributes to understanding of novel mechanisms of toxicity and provide new research tools or prototypes of therapeutic agents. The pygmy copperhead (Austrelaps labialis) is one of the less studied species. In this present study, an attempt has been made to describe the toxin profile of A. labialis from Kangaroo Island using the cDNA library of its venom glands. We sequenced 658 clones which represent the common families of toxin genes present in snake venom. They include (a) putative long-chain and short-chain neurotoxins, (b) phospholipase A2, (c) Kunitz-type protease inhibitor, (d) CRISPs, (e) C-type lectins and (f) Metalloproteases. In addition, we have also identified a novel protein with two Kunitz-type domains in tandem similar to bikunin. Interestingly, the cDNA library reveals that most of the toxin families (17 out of 43 toxin genes; approximately 40%) have truncated transcripts due to insertion or deletion of nucleotides. These truncated products might not be functionally active proteins. However, cellular transcripts from the same venom glands are not affected. This unusual higher rate of deletion and insertion of nucleotide in toxin genes may be responsible for the lower toxicity of A. labialis venom of Kangroo Island and have significant effect on evolution of toxin genes.

  7. Complement components 2 and 7 (C2 and C7) gene polymorphisms are not major risk factors for SLE susceptibility in the Malaysian population.

    Science.gov (United States)

    Lian, Lay-Hoong; Ching, Ai-Sze; Chong, Zheng-Yi; Chua, Kek-Heng

    2012-11-01

    There have been numerous studies linking complement components and the pathogenesis of systemic lupus erythematosus (SLE). This is due to their numerous roles in modulating immune responses in the human body. This study examined the association of C2 and C7 genetic polymorphisms with the susceptibility to SLE based on two separate cohorts of patient and control samples from Malaysia. The 28-bp deletion in the C2 exon-intron junction and single nucleotide polymorphism in the 3'untranslated region in the C7 genes were detected based on direct polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively. A total of 150 patient and 150 healthy control samples were screened, but there was no association detected between either genes. All individuals presented with null deletion in C2 genes, while the C allele and CC genotypes were most commonly scored. These overall results suggest a lack of strong association with the C2 and C7 gene polymorphisms to the susceptibility of SLE in the Malaysian population.

  8. Characterisation of the paralytic shellfish toxin biosynthesis gene clusters in Anabaena circinalis AWQC131C and Aphanizomenon sp. NH-5

    Directory of Open Access Journals (Sweden)

    Neilan Brett A

    2009-03-01

    Full Text Available Abstract Background Saxitoxin and its analogues collectively known as the paralytic shellfish toxins (PSTs are neurotoxic alkaloids and are the cause of the syndrome named paralytic shellfish poisoning. PSTs are produced by a unique biosynthetic pathway, which involves reactions that are rare in microbial metabolic pathways. Nevertheless, distantly related organisms such as dinoflagellates and cyanobacteria appear to produce these toxins using the same pathway. Hypothesised explanations for such an unusual phylogenetic distribution of this shared uncommon metabolic pathway, include a polyphyletic origin, an involvement of symbiotic bacteria, and horizontal gene transfer. Results We describe the identification, annotation and bioinformatic characterisation of the putative paralytic shellfish toxin biosynthesis clusters in an Australian isolate of Anabaena circinalis and an American isolate of Aphanizomenon sp., both members of the Nostocales. These putative PST gene clusters span approximately 28 kb and contain genes coding for the biosynthesis and export of the toxin. A putative insertion/excision site in the Australian Anabaena circinalis AWQC131C was identified, and the organization and evolution of the gene clusters are discussed. A biosynthetic pathway leading to the formation of saxitoxin and its analogues in these organisms is proposed. Conclusion The PST biosynthesis gene cluster presents a mosaic structure, whereby genes have apparently transposed in segments of varying size, resulting in different gene arrangements in all three sxt clusters sequenced so far. The gene cluster organizational structure and sequence similarity seems to reflect the phylogeny of the producer organisms, indicating that the gene clusters have an ancient origin, or that their lateral transfer was also an ancient event. The knowledge we gain from the characterisation of the PST biosynthesis gene clusters, including the identity and sequence of the genes involved

  9. Recombinant cholera toxin B subunit and gene fusion proteins for oral vaccination.

    Science.gov (United States)

    Sanchez, J; Johansson, S; Löwenadler, B; Svennerholm, A M; Holmgren, J

    1990-01-01

    The B subunit portion of cholera toxin (CTB) is a safe and effective oral immunizing agent in humans, affording protection against both cholera and diarrhoea caused by enterotoxigenic Escherichia coli producing heat-labile toxin (LT) (Clemens et al., 1986; 1988). CTB may also be used as a carrier of various "foreign" antigens suitable for oral administration. To facilitate large-scale production of CTB for vaccine development purposes, we have constructed recombinant overexpression systems for CTB proteins in which the CTB gene is under the control of strong foreign (non-cholera) promoters and in which it is also possible to fuse oligonucleotides to the CTB gene and thereby achieve overexpression of hybrid proteins (Sanchez and Holmgren, 1989; Sanchez et al., 1988). We here expand these findings by describing overexpression of CTB by a constitutive tacP promoter as well as by the T7 RNA-polymerase promoter, and also by describing gene fusions leading to overexpression of several hybrid proteins between heat-stable E. coli enterotoxin (STa)-related peptides to either the amino or carboxy ends of CTB. Each of the hybrid proteins, when tested as immunogens in rabbits, stimulated significant anti-STa as well as anti-CTB antibody formation, although the anti-STa antibody levels attained (c.a. 1-15 micrograms/ml specific anti-STa immunoglobulin) were too low to give more than partial neutralization of STa intestinal challenge in baby mice. The hybrid proteins also had a near-native conformation, as apparent from their oligomeric nature and their strong reactivity with both a neutralizing antibody against the B subunit and a neutralizing monoclonal antibody (mAb) against STa.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. C2H2 zinc finger genes of the Gli, Zic, KLF, SP, Wilms' tumour, Huckebein, Snail, Ovo, Spalt, Odd, Blimp-1, Fez and related gene families from Branchiostoma floridae.

    Science.gov (United States)

    Shimeld, Sebastian M

    2008-12-01

    The C2H2 zinc finger is one of the most common domains encoded by animal genomes and has been implicated in DNA binding as well as protein-protein interactions and RNA binding. Genes encoding C2H2 zinc finger domains include not only well-studied conserved transcription factors such as Gli and Snail but also include a large diversity of more rapidly evolving genes. Here, I focus on the description of amphioxus members of families and super-families of C2H2 zinc finger genes that have been the subject of functional studies in other species, specifically the Gli, Zic, Glis, Snail, Scratch, Krox, Wilms' tumour, Huckebein, SP, KLF, Ovo, Spalt, Blimp-1, Odd and Fez genes. Surveys of the Branchiostoma floridae genome reveal members of all of these groups of genes. Genes are named according to molecular phylogenetic analyses, such that the nomenclature reflects pre-existing gene names in the context of gene families that have descended from a single common ancestral gene in the common ancestor of chordates and insects. In total, this comprises 28 B. floridae C2H2 zinc finger genes, representing at least 15 gene families. For 17 of these genes, expressed sequence tag clusters and associated clone identification codes relating to the B. floridae gene collection are given.

  11. Viral promoters can initiate expression of toxin genes introduced into Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jacob Daniela

    2005-06-01

    Full Text Available Abstract Background The expression of recombinant proteins in eukaryotic cells requires the fusion of the coding region to a promoter functional in the eukaryotic cell line. Viral promoters are very often used for this purpose. The preceding cloning procedures are usually performed in Escherichia coli and it is therefore of interest if the foreign promoter results in an expression of the gene in bacteria. In the case molecules toxic for humans are to be expressed, this knowledge is indispensable for the specification of safety measures. Results We selected five frequently used viral promoters and quantified their activity in E. coli with a reporter system. Only the promoter from the thymidine kinase gene from HSV1 showed no activity, while the polyhedrin promoter from baculovirus, the early immediate CMV promoter, the early SV40 promoter and the 5' LTR promoter from HIV-1 directed gene expression in E. coli. The determination of transcription start sites in the immediate early CMV promoter and the polyhedrin promoter confirmed the existence of bacterial -10 and -35 consensus sequences. The importance of this heterologous gene expression for safety considerations was further supported by analysing fusions between the aforementioned promoters and a promoter-less cytotoxin gene. Conclusion According to our results a high percentage of viral promoters have the ability of initiating gene expression in E. coli. The degree of such heterologous gene expression can be sufficient for the expression of toxin genes and must therefore be considered when defining safety measures for the handling of corresponding genetically modified organisms.

  12. C2C12 myotubes inhibit the proliferation and differentiation of 3T3-L1 preadipocytes by reducing the expression of glucocorticoid receptor gene

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Weiwei; Wei, Wei; Yu, Shigang; Han, Haiyin; Shi, Xiaoli [College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095 (China); Sun, Wenxing [College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095 (China); College of Public Health, Nantong University, Nantong 226019 (China); Gao, Ying [College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095 (China); Zhang, Lifan [College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095 (China); Chen, Jie, E-mail: jiechen@njau.edu.cn [College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095 (China)

    2016-03-25

    Obesity is a well-established risk factor to health for its relationship with insulin resistance, diabetes and metabolic syndrome. Myocyte-adipocyte crosstalk model plays a significant role in studying the interaction of muscle and adipose development. Previous related studies mainly focus on the effects of adipocytes on the myocytes activity, however, the influence of myotubes on the preadipocytes development remains unclear. The present study was carried out to settle this issue. Firstly, the co-culture experiment showed that the proliferation, cell cycle, and differentiation of 3T3-L1 preadipocytes were arrested, and the apoptosis was induced, by differentiated C2C12 myotubes. Next, the sensitivity of 3T3-L1 preadipocytes to glucocorticoids (GCs), which was well known as cell proliferation, differentiation, apoptosis factor, was decreased after co-cultured with C2C12 myotubes. What's more, our results showed that C2C12 myotubes suppressed the mRNA and protein expression of glucocorticoid receptor (GR) in 3T3-L1 preadipocytes, indicating the potential mechanism of GCs sensitivity reduction. Taken together, we conclude that C2C12 myotubes inhibited 3T3-L1 preadipocytes proliferation and differentiation by reducing the expression of GR. These data suggest that decreasing GR by administration of myokines may be a promising therapy for treating patients with obesity or diabetes. - Highlights: • C2C12 myotubes inhibited proliferation and differentiation of 3T3-L1 preadipocytes. • C2C12 myotubes arrested cell cycle of 3T3-L1 preadipocytes. • C2C12 myotubes induced apoptosis of 3T3-L1 preadipocytes. • C2C12 inhibit 3T3-L1 cells by reducing the expression of glucocorticoid receptor gene.

  13. Identification and expression of C2H2 transcription factor genes in Carica papaya under abiotic and biotic stresses.

    Science.gov (United States)

    Jiang, Ling; Pan, Lin-jie

    2012-06-01

    C2H2 proteins belong to a group of transcription factors (TFs) existing as a superfamily that plays important roles in defense responses and various other physiological processes in plants. The present study aimed to screen for and identify C2H2 proteins associated with defense responses to abiotic and biotic stresses in Carica papaya L. Data were collected for 47,483 papaya-expressed sequence tags (ESTs). The full-length cDNA nucleotide sequences of 87 C2H2 proteins were predicated by BioEdit. All 91 C2H2 proteins were aligned, and a phylogenetic tree was constructed using DNAman. The expression levels of 42 C2H2 were analyzed under conditions of salt stress by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Methyl jasmonate treatment rapidly upregulated ZF(23.4) and ZF(30,912.1) by 18.6- and 21.7-fold, respectively. ZF(1.3), ZF(138.44), ZF(94.49), ZF(29.160), and ZF(20.206) were found to be downregulated after low temperature treatment at very significant levels (p papaya ringspot virus pathogen. ZF(30,912.1) was subcellularly localized in the nucleus by a transgenic fusion of pBS-ZF(30,912.1)-GFP into the protoplast of papaya. The results of the present study showed that ZF(30,912.1) could be an important TF that mediates responses to abiotic and biotic stresses in papaya.

  14. Direct detection of diarrheagenic Aeromonas from faeces by polymerase chain reaction (PCR) targeting aerolysin toxin gene.

    Science.gov (United States)

    Kannan, S; Suresh Kanna, P; Karkuzhali, K; Chattopadhyay, U K; Pal, D

    2001-01-01

    Detection of diarrheagenic Aeromonas specific aerolysin toxin (Aer) gene by PCR based assay and isolation, identification of diarrhea causing Aeromonas from faeces by culture methods were carried out in the Division of Active Surveillance, National Institute of Cholera and Enteric Diseases (NICED), Kolkata, India for a period of 12 months. Out of 602 faecal samples collected from patients with acute diarrhea admitted in Infectious Diseases (ID) Hospital, Kolkata, 68 (11.29%) samples were found to be possessing Aer gene by PCR technique. The conventional culture methods using selective media yielded only 64 (10.6%) Aeromonas strains from the same faecal samples. The different Aeromonas species possessing Aer gene identified by PCR based technique include A. hydrophila (55.8%), A. caviae (17.6%), A. veronii (10.2%), A. schubertii (4.4%), A. jandaei (2.9%) and A. trota (8.8%). The isolation and identification of Aeromonas by routine culture did not detect enterotoxigenic A. trota present in four diarrheal faecal samples. The failure of the growth of enterotoxigenic A. trota on selective media may be attributed to the ampicillin susceptibility of those strains. The quality control studies revealed that PCR method for the direct detection of Aer gene from the faeces has the sensitivity of 100% and specificity of 98%.

  15. BOTULINUM TOXIN

    Science.gov (United States)

    Nigam, P K; Nigam, Anjana

    2010-01-01

    Botulinum toxin, one of the most poisonous biological substances known, is a neurotoxin produced by the bacterium Clostridium botulinum. C. botulinum elaborates eight antigenically distinguishable exotoxins (A, B, C1, C2, D, E, F and G). All serotypes interfere with neural transmission by blocking the release of acetylcholine, the principal neurotransmitter at the neuromuscular junction, causing muscle paralysis. The weakness induced by injection with botulinum toxin A usually lasts about three months. Botulinum toxins now play a very significant role in the management of a wide variety of medical conditions, especially strabismus and focal dystonias, hemifacial spasm, and various spastic movement disorders, headaches, hypersalivation, hyperhidrosis, and some chronic conditions that respond only partially to medical treatment. The list of possible new indications is rapidly expanding. The cosmetological applications include correction of lines, creases and wrinkling all over the face, chin, neck, and chest to dermatological applications such as hyperhidrosis. Injections with botulinum toxin are generally well tolerated and side effects are few. A precise knowledge and understanding of the functional anatomy of the mimetic muscles is absolutely necessary to correctly use botulinum toxins in clinical practice. PMID:20418969

  16. Botulinum toxin

    Directory of Open Access Journals (Sweden)

    Nigam P

    2010-01-01

    Full Text Available Botulinum toxin, one of the most poisonous biological substances known, is a neurotoxin produced by the bacterium Clostridium botulinum. C. botulinum elaborates eight antigenically distinguishable exotoxins (A, B, C 1 , C 2 , D, E, F and G. All serotypes interfere with neural transmission by blocking the release of acetylcholine, the principal neurotransmitter at the neuromuscular junction, causing muscle paralysis. The weakness induced by injection with botulinum toxin A usually lasts about three months. Botulinum toxins now play a very significant role in the management of a wide variety of medical conditions, especially strabismus and focal dystonias, hemifacial spasm, and various spastic movement disorders, headaches, hypersalivation, hyperhidrosis, and some chronic conditions that respond only partially to medical treatment. The list of possible new indications is rapidly expanding. The cosmetological applications include correction of lines, creases and wrinkling all over the face, chin, neck, and chest to dermatological applications such as hyperhidrosis. Injections with botulinum toxin are generally well tolerated and side effects are few. A precise knowledge and understanding of the functional anatomy of the mimetic muscles is absolutely necessary to correctly use botulinum toxins in clinical practice.

  17. Insight into Shiga toxin genes encoded by Escherichia coli O157 from whole genome sequencing

    Directory of Open Access Journals (Sweden)

    Philip M. Ashton

    2015-02-01

    Full Text Available The ability of Shiga toxin-producing Escherichia coli (STEC to cause severe illness in humans is determined by multiple host factors and bacterial characteristics, including Shiga toxin (Stx subtype. Given the link between Stx2a subtype and disease severity, we sought to identify the stx subtypes present in whole genome sequences (WGS of 444 isolates of STEC O157. Difficulties in assembling the stx genes in some strains were overcome by using two complementary bioinformatics methods: mapping and de novo assembly. We compared the WGS analysis with the results obtained using a PCR approach and investigated the diversity within and between the subtypes. All strains of STEC O157 in this study had stx1a, stx2a or stx2c or a combination of these three genes. There was over 99% (442/444 concordance between PCR and WGS. When common source strains were excluded, 236/349 strains of STEC O157 had multiple copies of different Stx subtypes and 54 had multiple copies of the same Stx subtype. Of those strains harbouring multiple copies of the same Stx subtype, 33 had variants between the alleles while 21 had identical copies. Strains harbouring Stx2a only were most commonly found to have multiple alleles of the same subtype (42%. Both the PCR and WGS approach to stx subtyping provided a good level of sensitivity and specificity. In addition, the WGS data also showed there were a significant proportion of strains harbouring multiple alleles of the same Stx subtype associated with clinical disease in England.

  18. Regulation of anthrax toxin activator gene (atxA) expression in Bacillus anthracis: temperature, not CO2/bicarbonate, affects AtxA synthesis.

    OpenAIRE

    Dai, Z; Koehler, T M

    1997-01-01

    Anthrax toxin gene expression in Bacillus anthracis is dependent on the presence of atxA, a trans-acting regulatory gene located on the resident 185-kb plasmid pXO1. In atxA+ strains, expression of the toxin genes (pag, lef, and cya) is enhanced by two physiologically significant signals: elevated CO2/bicarbonate and temperature. To determine whether increased toxin gene expression in response to these signals is associated with increased atxA expression, we monitored steady-state levels of a...

  19. Virulence gene profiles of Shiga-toxin producing Escherichia coli isolates from retail raw meat in Iran

    OpenAIRE

    M. Panahee; H. Pourtaghi

    2017-01-01

    Shiga toxin-producing Escherichia coli (STEC) is recognised as toxin producing group of E. coli and one of the most significant foodborne pathogens worldwide. The aim of this study was to detect STEC and determine virulence gene profiles of these pathogens in different kinds of meat and prod-ucts in Iran. For this reason a total of 182 samples of minced beef, mutton, chicken meat, chicken feet and mechanically separated chicken meat were collected from retail markets for detection of STEC by ...

  20. Antibiotic Susceptibility, Genetic Diversity, and the Presence of Toxin Producing Genes in Campylobacter Isolates from Poultry

    Directory of Open Access Journals (Sweden)

    Jeeyeon Lee

    2017-11-01

    Full Text Available This study examined antibiotic susceptibility, genetic diversity, and characteristics of virulence genes in Campylobacter isolates from poultry. Chicken (n = 152 and duck (n = 154 samples were collected from 18 wet markets in Korea. Campylobacter spp. isolated from the carcasses were identified by PCR. The isolated colonies were analyzed for antibiotic susceptibility to chloramphenicol, amikacin, erythromycin, tetracycline, ciprofloxacin, nalidixic acid, and enrofloxacin. The isolates were also used to analyze genetic diversity using the DiversiLabTM system and were tested for the presence of cytolethal distending toxin (cdt genes. Campylobacter spp. were isolated from 45 poultry samples out of 306 poultry samples (14.7% and the average levels of Campylobacter contamination were 22.0 CFU/g and 366.1 CFU/g in chicken and duck samples, respectively. Moreover, more than 90% of the isolates showed resistance to nalidixic acid and ciprofloxacin. Genetic correlation analysis showed greater than 95% similarity between 84.4% of the isolates, and three cdt genes (cdtA, cdtB, and cdtC were present in 71.1% of Campylobacter isolates. These results indicate that Campylobacter contamination should be decreased to prevent and treat Campylobacter foodborne illness.

  1. Horizontal gene transfer of toxin genes in Clostridium botulinum: Involvement of mobile elements and plasmids

    OpenAIRE

    Skarin, Hanna; Segerman, Bo

    2011-01-01

    Intoxication with the potent botulinum neurotoxin (BoNT) gives rise to the serious paralytic illness botulism. BoNT is part of a complex that consists of the neurotoxin and several associated components, all encoded by the bont gene cluster. This gene cluster has likely been subjected to horizontal gene transfer between different groups of clostridia, which has given rise to the genetically diverse species Clostridium botulinum. C. botulinum is divided into four physiological groups (I–IV), w...

  2. A Double Selection Approach to Achieve Specific Expression of Toxin Genes for Ovarian Cancer Gene Therapy

    Science.gov (United States)

    2005-11-01

    rceiviing no knob valuecd rt I0",ý (I󈨋 C)o antrbodv blocks. Ad15-rt1 acne transfer (71 arrtibody was incubated with Ad5-mI1 or AcISLuc I at 100s .p/cc...deficient U118 MG cell line. Conversely, Ad5Lucl-CK1 dog kidney and SKOV3. ipl ovarian cancer cells with the gene delivery in U118 MG cells was about 100...Although the Ad5 fiber-knob Lucl-CKI gene transfer in only SKOV3. ipl cells but not competitively inhibited Ad5Lucl-mediated gene transfer completely

  3. Valporic acid enhances the Atrial Natriuretic Peptide (ANP) mediated anti-hypertrophic activity by modulating the Npr1 gene transcription in H9c2 cells in vitro.

    Science.gov (United States)

    Manivasagam, Senthamizharasi; Velusamy, Tamilselvi; Sowndharajan, Boopathi; Chandrasekar, Navvi; Dhanusu, Suresh; Vellaichamy, Elangovan

    2017-10-15

    The present study was aimed to determine whether stimulating Npr1 gene activity using Valporic acid (VA), a small short chain fatty acid molecule can enhance ANP mediated anti-hypertrophic activity in isoproterenol (ISO) - treated H9c2 cells in vitro. H9c2 cells were treated with ISO (10 -5 M) and co-treated with VA (10 -5 M) in the presence and absence of ANP (10 -8 M), for 48h. ATRA (10 -5 M) was used as a positive inducer of Npr1 gene transcription. The mRNA expression of Npr1 and PKG-I genes, proto-oncogenes (c-fos, c-jun and c-myc) and hypertrophic markers (ANP, BNP, α-sk and β-MyHC), genes were determined by quantitative PCR (qPCR). The protein profiling of NPR-A, PKG-I and cGMP were evaluated by Western blot, immunofluorescence and ELISA respectively. A marked reduction in the level of expression of Npr1 (3- fold) and PKG-I (2.5-fold) genes and increased expression of proto-oncogenes (pANP mediated anti-hypertrophic activity was enhanced with either VA (pANP can be a novel therapeutical approach for the treatment and management of left ventricular cardiac hypertrophy. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Anti-cancer Parasporin Toxins are Associated with Different Environments: Discovery of Two Novel Parasporin 5-like Genes.

    Science.gov (United States)

    Ammons, David R; Short, John D; Bailey, Jeffery; Hinojosa, Gabriela; Tavarez, Lourdes; Salazar, Martha; Rampersad, Joanne N

    2016-02-01

    Cry toxins are primarily a family of insecticidal toxins produced by the bacterium Bacillus thuringiensis (Bt). However, some Cry toxins, called parasporins (PSs), are non-insecticidal and have been shown to differentially kill human cancer cells. Based on amino acid homology, there are currently six different classes of parasporins (PS1-6). It is not known what role parasporins play in nature, nor if certain PSs are associated with Bt found in particular environments. Herein, we present ten parasporin-containing isolates of Bt from the Caribbean island of Trinidad. Genes coding for PS1 and PS6 were found in isolates associated mainly with artificial aquatic environments (e.g., barrels with rain water), while Bt possessing two novel PS5-like genes (ps5-1 and ps5-2), were isolated from manure collected directly from the rectum of cattle. The amino acid sequences inferred from the two PS5-like genes were 51 % homologous to each other, while being only 41 or 45 % similar to PS5Aa1/Cry64Aa, the only reported member of the parasporin five class. The low level of amino acid homology between the two PS5-like genes and PS5Aa1 indicate that the two PS5-like genes may represent a new class of parasporins, or greatly expand the level of diversity within the current parasporin 5 class.

  5. Virulence genes of Aeromonas isolates, bacterial endotoxins and cyanobacterial toxins from recreational water samples associated with human health symptoms.

    Science.gov (United States)

    Berg, Katri A; Lyra, Christina; Niemi, R Maarit; Heens, Benoit; Hoppu, Kalle; Erkomaa, Kirsti; Sivonen, Kaarina; Rapala, Jarkko

    2011-12-01

    Exposure to cyanobacterial water blooms has been associated with various kinds of adverse health effects. In addition to cyanobacteria and their toxins, the bacteria associated with cyanobacteria could also be the etiological agents. We isolated Aeromonas strains (n = 176) from water samples (n = 38) taken from sites where cyanobacteria were suspected to have caused human health symptoms, of which fever and gastrointestinal symptoms were the most common. The isolates were screened by PCR for six virulence gene types (12 genes). The majority (90%) of the strains contained at least one of the virulence genes. Most common amplification products were those of genes (act/aerA/hlyA) that encode cytotoxic enterotoxin and haemolytic products. The genes encoding cytotonic enterotoxins (ast and alt), phospholipase (lip/pla/lipH3/alp-1), elastase (ahyB) and flagellin subunits (flaA/flaB) were also present in 5-37% of the Aeromonas strains. Analysed toxins (cyanobacterial hepatotoxins and neurotoxins, and bacterial endotoxins) were not detectable or were present in only low concentrations in the majority of the samples. The results indicated that the toxins were unlikely to be the main cause of the reported adverse health effects, whereas more attention should be paid to bacteria associated with cyanobacteria as a source of health effects.

  6. Effects of sphingosine-1-phosphate on gene expression of two cell mouse embryos induced by C2-Ceramide

    Directory of Open Access Journals (Sweden)

    Xujing Geng

    2014-06-01

    Conclusions: This study provides a map of genes in the pre-implantation two cell mouse embryo. Further investigation based on these data will provide a better understanding of the effects of S1P on the pre-implantation embryos in other mammalian species, especially human.

  7. Unveiling novel genes upregulated by both rhBMP2 and rhBMP7 during early osteoblastic transdifferentiation of C2C12 cells

    Directory of Open Access Journals (Sweden)

    Sogayar Mari C

    2011-09-01

    Full Text Available Abstract Findings We set out to analyse the gene expression profile of pre-osteoblastic C2C12 cells during osteodifferentiation induced by both rhBMP2 and rhBMP7 using DNA microarrays. Induced and repressed genes were intercepted, resulting in 1,318 induced genes and 704 repressed genes by both rhBMP2 and rhBMP7. We selected and validated, by RT-qPCR, 24 genes which were upregulated by rhBMP2 and rhBMP7; of these, 13 are related to transcription (Runx2, Dlx1, Dlx2, Dlx5, Id1, Id2, Id3, Fkhr1, Osx, Hoxc8, Glis1, Glis3 and Cfdp1, four are associated with cell signalling pathways (Lrp6, Dvl1, Ecsit and PKCδ and seven are associated with the extracellular matrix (Ltbp2, Grn, Postn, Plod1, BMP1, Htra1 and IGFBP-rP10. The novel identified genes include: Hoxc8, Glis1, Glis3, Ecsit, PKCδ, LrP6, Dvl1, Grn, BMP1, Ltbp2, Plod1, Htra1 and IGFBP-rP10. Background BMPs (bone morphogenetic proteins are members of the TGFβ (transforming growth factor-β super-family of proteins, which regulate growth and differentiation of different cell types in various tissues, and play a critical role in the differentiation of mesenchymal cells into osteoblasts. In particular, rhBMP2 and rhBMP7 promote osteoinduction in vitro and in vivo, and both proteins are therapeutically applied in orthopaedics and dentistry. Conclusion Using DNA microarrays and RT-qPCR, we identified both previously known and novel genes which are upregulated by rhBMP2 and rhBMP7 during the onset of osteoblastic transdifferentiation of pre-myoblastic C2C12 cells. Subsequent studies of these genes in C2C12 and mesenchymal or pre-osteoblastic cells should reveal more details about their role during this type of cellular differentiation induced by BMP2 or BMP7. These studies are relevant to better understanding the molecular mechanisms underlying osteoblastic differentiation and bone repair.

  8. Unusual accelerated rate of deletions and insertions in toxin genes in the venom glands of the pygmy copperhead (Austrelaps labialis from kangaroo island

    Directory of Open Access Journals (Sweden)

    Kini R Manjunatha

    2008-02-01

    Full Text Available Abstract Background Toxin profiling helps in cataloguing the toxin present in the venom as well as in searching for novel toxins. The former helps in understanding potential pharmacological profile of the venom and evolution of toxins, while the latter contributes to understanding of novel mechanisms of toxicity and provide new research tools or prototypes of therapeutic agents. Results The pygmy copperhead (Austrelaps labialis is one of the less studied species. In this present study, an attempt has been made to describe the toxin profile of A. labialis from Kangaroo Island using the cDNA library of its venom glands. We sequenced 658 clones which represent the common families of toxin genes present in snake venom. They include (a putative long-chain and short-chain neurotoxins, (b phospholipase A2, (c Kunitz-type protease inhibitor, (d CRISPs, (e C-type lectins and (f Metalloproteases. In addition, we have also identified a novel protein with two Kunitz-type domains in tandem similar to bikunin. Conclusion Interestingly, the cDNA library reveals that most of the toxin families (17 out of 43 toxin genes; ~40% have truncated transcripts due to insertion or deletion of nucleotides. These truncated products might not be functionally active proteins. However, cellular trancripts from the same venom glands are not affected. This unusual higher rate of deletion and insertion of nucleotide in toxin genes may be responsible for the lower toxicity of A. labialis venom of Kangroo Island and have significant effect on evolution of toxin genes.

  9. Quantification of Cell Proliferation and Alpha-Toxin Gene Expression of Clostridium perfringens in the Development of Necrotic Enteritis in Broiler Chickens▿

    OpenAIRE

    Si, Weiduo; Gong, Joshua; Han, Yanming; Yu, Hai; Brennan, John; Zhou, Huaijun; Chen, Shu

    2007-01-01

    Cell proliferation and alpha-toxin gene expression of Clostridium perfringens in relation to the development of necrotic enteritis (NE) were investigated. Unlike bacitracin-treated chickens, non-bacitracin-treated birds exhibited typical NE symptoms and reduced growth performance. They also demonstrated increased C. perfringens proliferation and alpha-toxin gene expression that were positively correlated and progressed according to the regression model y = b0 + b1X − b2X2. The average C. perf...

  10. Identification of Anthrax Toxin Genes in a Bacillus cereus Associated With An Illness Resembling Inhalation Anthrax

    National Research Council Canada - National Science Library

    Hoffmaster, Alex R; Ravel, Jacques; Rasko, David A; Chapman, Gail D; Chute, Michael D; Marston, CHung K; De, Barun K; Sacchi, Claudio T; Fitzgerald, Collette

    2004-01-01

    .... It was thought to differ from Bacillus cereus, an opportunistic pathogen and cause of food poisoning, by the presence of plasmids pXO1 and pXO2, which encode the lethal toxin complex and the poly- -D...

  11. Streptococcus sp. and Staphylococcus aureus isolates from patients with psoriasis possess genes that code for toxins (superantigens): clinical and therapeutic implications.

    Science.gov (United States)

    El Ferezli, Jessica; Jenbazian, Lori; Rubeiz, Nelly; Kibbi, Abdul-Ghani; Zaynoun, Shukrallah; Abdelnoor, Alexander M

    2008-01-01

    Superantigens are powerful T lymphocyte-stimulating agents that are believed to contribute to the pathogenesis of certain diseases such as psoriasis. Toxins produced by Streptococcus pyogenes and Staphylococcus aureus are superantigens. The aim of this study was to detect genes that code for superantigens in Streptococcus and Staphylococcus aureus isolates from psoriatic patients. Primers to amplify streptococcal pyrogenic exotoxin A, B, and C and streptolysin O genes and staphylococcal enterotoxin A, B, C, and D genes were used. Streptococcal exotoxin B was detected in five streptococcal isolates. Staphyloccocus aureus enterotoxin A and/or C genes were detected in nine S. aureus isolates. Isolates from 13 of 22 patients possesed gene(s) that code for toxin(s) (superantigens). These results might support the role of superantigens in the exacerbation of psoriasis.

  12. Deletion of 16q24.1 supports a role for the ATP2C2 gene in specific language impairment.

    Science.gov (United States)

    Smith, Amena W; Holden, Kenton R; Dwivedi, Alka; Dupont, Barbara R; Lyons, Michael J

    2015-03-01

    A 10-year-old boy presented with a history of significant delay in language acquisition as well as receptive and expressive language impairment that persisted into elementary school. In school, he exhibited difficulty with reading comprehension, telling and understanding narratives, and making inferences. Other aspects of his neurodevelopment were normal, with no history of significant medical concerns. He did not have hearing impairment, oromotor dysfunction, or specific neurologic abnormalities. He did not meet testing criteria for autism. Chromosomal microarray analysis and quantitative polymerase chain reaction determined that he had a de novo 159-kilobase deletion of chromosome 16q24.1 that included the ATP2C2 gene. ATP2C2 is a known candidate gene for specific language impairment and is postulated to have neurobiological significance in memory-related circuits. Our patient's language deficits were consistent with a global type of specific language impairment impacting language comprehension, formulation, semantics, syntax, and phonology attributed to his de novo chromosome deletion. © The Author(s) 2014.

  13. A longevity assurance gene homolog of tomato mediates resistance to Alternaria alternata f. sp. lycopersici toxins and fumonisin B1

    Science.gov (United States)

    Brandwagt, Bas F.; Mesbah, Laurent A.; Takken, Frank L. W.; Laurent, Pascal L.; Kneppers, Tarcies J. A.; Hille, Jacques; Nijkamp, H. John J.

    2000-01-01

    The phytopathogenic fungus Alternaria alternata f. sp. lycopersici (AAL) produces toxins that are essential for pathogenicity of the fungus on tomato (Lycopersicon esculentum). AAL toxins and fumonisins of the unrelated fungus Fusarium moniliforme are sphinganine-analog mycotoxins (SAMs), which cause inhibition of sphingolipid biosynthesis in vitro and are toxic for some plant species and mammalian cell lines. Sphingolipids can be determinants in the proliferation or death of cells. We investigated the tomato Alternaria stem canker (Asc) locus, which mediates resistance to SAM-induced apoptosis. Until now, mycotoxin resistance of plants has been associated with detoxification and altered affinity or absence of the toxin targets. Here we show that SAM resistance of tomato is determined by Asc-1, a gene homologous to the yeast longevity assurance gene LAG1 and that susceptibility is associated with a mutant Asc-1. Because both sphingolipid synthesis and LAG1 facilitate endocytosis of glycosylphosphatidylinositol-anchored proteins in yeast, we propose a role for Asc-1 in a salvage mechanism of sphingolipid-depleted plant cells. PMID:10781105

  14. Bacillus subtilis HJ18-4 from traditional fermented soybean food inhibits Bacillus cereus growth and toxin-related genes.

    Science.gov (United States)

    Eom, Jeong Seon; Lee, Sun Young; Choi, Hye Sun

    2014-11-01

    Bacillus subtilis HJ18-4 isolated from buckwheat sokseongjang, a traditional Korean fermented soybean food, exhibits broad-spectrum antimicrobial activity against foodborne pathogens, including Bacillus cereus. In this study, we investigated the antibacterial efficacy and regulation of toxin gene expression in B. cereus by B. subtilis HJ18-4. Expression of B. cereus toxin-related genes (groEL, nheA, nheC, and entFM) was downregulated by B. subtilis HJ18-4, which also exhibited strong antibacterial activity against B. cereus. We also found that water extracts of soy product fermented with B. subtilis HJ18-4 significantly inhibited the growth of B. cereus and toxin expression. These results indicate that B. subtilis HJ18-4 could be used as an antimicrobial agent to control B. cereus in the fermented soybean food industry. Our findings also provide an opportunity to develop an efficient biological control agent against B. cereus. © 2014 The Authors. Journal of Food Science published by Wiley Periodicals, Inc. on behalf of Institute of Food Technologists®

  15. Spatial, Temporal, and Matrix Variability of Clostridium botulinum Type E Toxin Gene Distribution at Great Lakes Beaches

    Science.gov (United States)

    Oster, Ryan J.; Haack, Sheridan K.; Fogarty, Lisa R.; Tucker, Taaja R.; Riley, Stephen C.

    2015-01-01

    Clostridium botulinum type E toxin is responsible for extensive mortality of birds and fish in the Great Lakes. The C. botulinum bontE gene that produces the type E toxin was amplified with quantitative PCR from 150 sloughed algal samples (primarily Cladophora species) collected during summer 2012 from 10 Great Lakes beaches in five states; concurrently, 74 sediment and 37 water samples from four sites were also analyzed. The bontE gene concentration in algae was significantly higher than in water and sediment (P Lake Front beaches (Lake Michigan) and Bay City State Recreation Area beach on Saginaw Bay (Lake Huron), where 77, 100, and 83% of these algal samples contained the bontE gene, respectively. The highest concentration of bontE was detected at Bay City (1.98 × 105 gene copies/ml of algae or 5.21 × 106 g [dry weight]). This study revealed that the bontE gene is abundant in the Great Lakes but that it has spatial, temporal, and matrix variability. Further, embayed beaches, low wave height, low wind velocity, and greater average water temperature enhance the bontE occurrence. PMID:25888178

  16. Cloning, Expression and Toxicity of a Mosquitocidal Toxin Gene of Bacillus thuringiensis subsp. medellin

    Directory of Open Access Journals (Sweden)

    Nora Restrepo

    1997-03-01

    Full Text Available Bacillus thuringiensis (Bt subsp. medellin (Btmed produces parasporal crystalline inclusions which are toxic to mosquito larvae. It has been shown that the inclusions of this bacterium contain mainly proteins of 94, 68 and 28-30 kDa. EcoRI partially digested total DNA of Btmed was cloned by using the Lambda Zap II cloning kit. Recombinant plaques were screened with a mouse policlonal antibody raised against the 94 kDa crystal protein of Btmed. One of the positive plaques was selected, and by in vivo excision, a recombinant pBluescript SK(- was obtained. The gene encoding the 94 kDa toxin of Btmed DNA was cloned in a 4.4 kb DNA fragment. Btmed DNA was then subcloned as a EcoRI/EcoRI fragment into the shuttle vector pBU4 producing the recombinant plasmid pBTM3 and used to transform by electroporation Bt subsp. israelensis (Bti crystal negative strain 4Q2-81. Toxicity to mosquito larvae was estimated by using first instar laboratory reared Aedes aegypti, and Culex quinquefasciatus larvae challenged with whole crystals. Toxicity results indicate that the purified inclusions from the recombinant Bti strain were toxic to all mosquito species tested, although the toxicity was not as high as the one produced by the crystal of the Btmed wild type strain. Poliacrylamide gel electrophoresis indicate that the inclusions produced by the recombinant strain Bti (pBTM3 were mainly composed of the 94 kDa protein of Btmed, as it was determined by Western blot

  17. Role of the host-selective ACT-toxin synthesis gene ACTTS2 encoding an enoyl-reductase in pathogenicity of the tangerine pathotype of Alternaria alternata.

    Science.gov (United States)

    Ajiro, Naoya; Miyamoto, Yoko; Masunaka, Akira; Tsuge, Takashi; Yamamoto, Mikihiro; Ohtani, Kouhei; Fukumoto, Takeshi; Gomi, Kenji; Peever, Tobin L; Izumi, Yuriko; Tada, Yasuomi; Akimitsu, Kazuya

    2010-02-01

    ABSTRACT The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease of tangerines and tangerine hybrids. Sequence analysis of a genomic BAC clone identified a previously uncharacterized portion of the ACT-toxin biosynthesis gene cluster (ACTT). A 1,034-bp gene encoding a putative enoyl-reductase was identified by using rapid amplification of cDNA ends and polymerase chain reaction and designated ACTTS2. Genomic Southern blots demonstrated that ACTTS2 is present only in ACT-toxin producers and is carried on a 1.9 Mb conditionally dispensable chromosome by the tangerine pathotype. Targeted gene disruption of ACTTS2 led to a reduction in ACT-toxin production and pathogenicity, and transcriptional knockdown of ACTTS2 using RNA silencing resulted in complete loss of ACT-toxin production and pathogenicity. These results indicate that ACTTS2 is an essential gene for ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and is required for pathogenicity of this fungus.

  18. High prevalence of diarrheagenic Escherichia coli carrying toxin-encoding genes isolated from children and adults in southeastern Brazil.

    Science.gov (United States)

    Spano, Liliana Cruz; da Cunha, Keyla Fonseca; Monfardini, Mariane Vedovatti; de Cássia Bergamaschi Fonseca, Rita; Scaletsky, Isabel Christina Affonso

    2017-12-18

    Diarrheagenic Escherichia coli (DEC) are important bacterial causes of childhood diarrhea in Brazil, but its impact in adults is unknown. This study aimed at investigating DEC among children and adults living in endemic areas. A total of 327 stools specimens were collected from children (n = 141) and adults (n = 186) with diarrhea attending health centers. Diarrheagenic E. coli (DEC) were identified by their virulence genes (multiplex polymerase chain reaction) and HEp-2 cell adherence patterns. DEC were detected in 56 (40%) children and 74 (39%) adults; enteroaggregative E. coli (EAEC) (23%) was the most prevalent pathotype, followed by diffusely adherent E. coli (DAEC) (13%), and occurred at similar frequencies in both diarrheal groups. Atypical enteropathogenic E. coli (aEPEC) strains were recovered more frequently from children (6%) than from adults (1%). Twenty-six percent of the EAEC were classified as typical EAEC possessing aggR gene, and carried the aap gene. EAEC strains carrying aggR-aap-aatA genes were significantly more frequent among children than adults (p < 0.05). DAEC strains possessing Afa/Dr. genes were detected from children (10%) and adults (6%). EAEC and DAEC strains harboring genes for the EAST1 (astA), Pet, Pic, and Sat toxins were common in both diarrheal groups. The astA and the porcine AE/associated adhesin (paa) genes were found in most of aEPEC strains. High levels of resistance to antimicrobial drugs were found among DAEC and aEPEC isolates. The results show a high proportion of EAEC and DAEC carrying toxin-encoding genes among adults with diarrhea.

  19. Virulence gene profiles of Shiga-toxin producing Escherichia coli isolates from retail raw meat in Iran

    Directory of Open Access Journals (Sweden)

    M. Panahee

    2017-03-01

    Full Text Available Shiga toxin-producing Escherichia coli (STEC is recognised as toxin producing group of E. coli and one of the most significant foodborne pathogens worldwide. The aim of this study was to detect STEC and determine virulence gene profiles of these pathogens in different kinds of meat and prod-ucts in Iran. For this reason a total of 182 samples of minced beef, mutton, chicken meat, chicken feet and mechanically separated chicken meat were collected from retail markets for detection of STEC by PCR method. Of the 72 E. coli isolated from examined samples, 29 of them were STEC. The highest presence of STEC was detected in minced beef (23.5% followed by chicken feet (15%, mutton (13.3%, mechanically separated chicken meat (12.5% and chicken meat (5.5% respectively. In addition the results of PCR assay indicated that 21 (72.4% and 4 (13.7% of isolates carried stx2 and eaeA genes respectively. However, according to the results stx2 was the most prevalent gene detected in all kinds of examined samples. Our findings showed that evaluation of the prevalence and viru-lence factors of this pathogen seems necessary considering the increasing importance of STEC as one of the most significant foodborne pathogens.

  20. Generation of divalent DNA vaccine based on p39 and shiga-like toxin 2 (Stx2 genes

    Directory of Open Access Journals (Sweden)

    Doosti Abbas

    2015-01-01

    Full Text Available The virulence factors such as shiga-like toxin (Stx and immunogenic P39 protein in Escherichia coli and Brucella melitensis are related to disease of digestive system in human worldwide. In the present study the stx2 and p39 genes were cloned into expression plasmid pEEF1D-FLAG (pcDNA 3.1+ as a divalent DNA vaccine candidate. The Enterohemorrhagic E. coli ATCC 3081 and smooth virulent B. melitensis strain M5 were obtained and cultured on specific media. Bacterial DNA was extracted from colonies and was used for p39 and stx2 genes amplification by PCR. The amplified products on 2% agarose gel electrophoresis were revealed 285 and 1220 bp fragments for stx2 and p39 genes, respectively. Each amplified genes were T/A cloned into pGEM-T easy vector and pGEM-T-stx2 and pGEM-T-p39 were produced. The stx2 and p39 genes were sub-cloned in linearized expression vector (pcDNA 3.1+ using HindIII, XhoI and XbaI restriction enzymes and pCDNA3-stx2-p39 was generated. This final construct was confirmed by PCR and enzymes digestion. The results were showed stx2 and p39 genes were sub-cloned, successfully into pcDNA 3.1+ to generate pcDNA 3.1+-stx2-p39 recombinant vector. According to these findings novel recombinant pcDNA 3.1+-stx2- p39 construct that was produced in this study could be useful as DNA vaccine candidate in animal models against shiga-like toxin producing E. coli and virulence B. melitensis strains in future studies.

  1. Survival of Clostridium perfringens During Simulated Transport and Stability of Some Plasmid-borne Toxin Genes under Aerobic Conditions

    Directory of Open Access Journals (Sweden)

    Johansson A

    2006-12-01

    Full Text Available Clostridium perfringens is a pathogen of great concern in veterinary medicine, because it causes enteric diseases and different types of toxaemias in domesticated animals. It is important that bacteria in tissue samples, which have been collected in the field, survive and for the classification of C. perfringens into the correct toxin group, it is crucial that plasmid-borne genes are not lost during transportation or in the diagnostic laboratory. The objectives of this study were to investigate the survival of C. perfringens in a simulated transport of field samples and to determine the stability of the plasmid-borne toxin genes cpb1 and etx after storage at room temperature and at 4°C. Stability of the plasmid-borne genes cpb1 and etx of C. perfringens CCUG 2035, and cpb2 from C. perfringens CIP 106526, JF 2255 and 6 field isolates in aerobic atmosphere was also studied. Survival of C. perfringens was similar in all experiments. The cpb1 and etx genes were detected in all isolates from samples stored either at room temperature or at 4°C for 24–44 h. Repeated aerobic treatment of C. perfringens CCUG 2035 and CIP 106526 did not result in the loss of the plasmid-borne genes cpb1, cpb2 or etx. Plasmid-borne genes in C. perfringens were found to be more stable than generally reported. Therefore, C. perfringens toxinotyping by PCR can be performed reliably, as the risk of plasmid loss seems to be a minor problem.

  2. Survival of Clostridium perfringens During Simulated Transport and Stability of Some Plasmid-borne Toxin Genes under Aerobic Conditions

    Directory of Open Access Journals (Sweden)

    Johansson K-E

    2005-12-01

    Full Text Available Clostridium perfringens is a pathogen of great concern in veterinary medicine, because it causes enteric diseases and different types of toxaemias in domesticated animals. It is important that bacteria in tissue samples, which have been collected in the field, survive and for the classification of C. perfringens into the correct toxin group, it is crucial that plasmid-borne genes are not lost during transportation or in the diagnostic laboratory. The objectives of this study were to investigate the survival of C. perfringens in a simulated transport of field samples and to determine the stability of the plasmid-borne toxin genes cpb1 and etx after storage at room temperature and at 4°C. Stability of the plasmid-borne genes cpb1 and etx of C. perfringens CCUG 2035, and cpb2 from C. perfringens CIP 106526, JF 2255 and 6 field isolates in aerobic atmosphere was also studied. Survival of C. perfringens was similar in all experiments. The cpb1 and etx genes were detected in all isolates from samples stored either at room temperature or at 4°C for 24–44 h. Repeated aerobic treatment of C. perfringens CCUG 2035 and CIP 106526 did not result in the loss of the plasmid-borne genes cpb1, cpb2 or etx. Plasmid-borne genes in C. perfringens were found to be more stable than generally reported. Therefore, C. perfringens toxinotyping by PCR can be performed reliably, as the risk of plasmid loss seems to be a minor problem.

  3. Function of genes encoding acyl-CoA synthetase and enoyl-CoA hydratase for host-selective act-toxin biosynthesis in the tangerine pathotype of Alternaria alternata.

    Science.gov (United States)

    Miyamoto, Y; Ishii, Y; Honda, A; Masunaka, A; Tsuge, T; Yamamoto, M; Ohtani, K; Fukumoto, T; Gomi, K; Peever, T L; Akimitsu, K

    2009-04-01

    The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease. Sequence analysis of a genomic cosmid clone identified a part of the ACTT gene cluster and implicated two genes, ACTT5 encoding an acyl-CoA synthetase and ACTT6 encoding an enoyl-CoA hydratase, in the biosynthesis of ACT-toxin. Genomic Southern blots demonstrated that both genes were present in tangerine pathotype isolates producing ACT-toxin and also in Japanese pear pathotype isolates producing AK-toxin and strawberry pathotype isolates producing AF-toxin. ACT-, AK-, and AF-toxins from these three pathotypes share a common 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid moiety. Targeted gene disruption of two copies of ACTT5 significantly reduced ACT-toxin production and virulence. Targeted gene disruption of two copies of ACTT6 led to complete loss of ACT-toxin production and pathogenicity and a putative decatrienoic acid intermediate in ACT-toxin biosynthesis accumulated in mycelial mats. These results indicate that ACTT5 and ACTT6 are essential genes in ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and both are required for full virulence of this fungus.

  4. The Genome Sequence of the Cyanobacterium Oscillatoria sp. PCC 6506 Reveals Several Gene Clusters Responsible for the Biosynthesis of Toxins and Secondary Metabolites▿

    Science.gov (United States)

    Méjean, Annick; Mazmouz, Rabia; Mann, Stéphane; Calteau, Alexandra; Médigue, Claudine; Ploux, Olivier

    2010-01-01

    We report a draft sequence of the genome of Oscillatoria sp. PCC 6506, a cyanobacterium that produces anatoxin-a and homoanatoxin-a, two neurotoxins, and cylindrospermopsin, a cytotoxin. Beside the clusters of genes responsible for the biosynthesis of these toxins, we have found other clusters of genes likely involved in the biosynthesis of not-yet-identified secondary metabolites. PMID:20675499

  5. Novel genes encoding six kinds of three-finger toxins in Ophiophagus hannah (king cobra) and function characterization of two recombinant long-chain neurotoxins.

    Science.gov (United States)

    Li, Jing; Zhang, Huayuan; Liu, Jing; Xu, Kangsen

    2006-09-01

    Three-finger toxins are a family of low-molecular-mass toxins (king cobra). Alignment analysis showed that the putative peptides could be divided into six kinds of three-finger toxins: LNTXs (long-chain neurotoxins), short-chain neurotoxins, cardiotoxins (CTXs), weak neurotoxins, muscarinic toxins and a toxin with a free SH group. Furthermore, a phylogenetic tree was established on the basis of the toxin cDNAs and the previously reported similar nucleotide sequences from the same source venom. It indicated that three-finger-toxin genes in O. hannah diverged early in the course of evolution by long- and short-type pathways. Two LNTXs, namely rLNTX1 (recombinant LNTX1) and rLNTX3, were expressed and showed cytolytic activity in addition to their neurotoxic function. By comparing the functional residues, we offer some possible explanations for the differences in their neurotoxic function. Moreover, a plausible elucidation of the additonal cytolytic activity was achieved by hydropathy-profile analysis. This, to our knowledge, is the first observation that recombinant long chain alpha-neurotoxins have a CTX-like cytolytic activity.

  6. Cloning and expression of Clostridium perfringens type D vaccine strain epsilon toxin gene in E. coli as a recombinant vaccine candidate.

    Science.gov (United States)

    Aziminia, Parastoo; Pilehchian-Langroudi, Reza; Esmaeilnia, Kasra

    2016-08-01

    Clostridium perfringens, a Gram-positive obligate anaerobic bacterium, is able to form resistant spores which are widely distributed in the environment. C. perfringens is subdivided into five types A to E based on its four major alpha, beta, epsilon and iota toxins. The aim of the present study was cloning and expression of C. perfringens type D vaccine strain epsilon toxin gene. Genomic DNA was extracted and the epsilon toxin gene was amplified using Pfu DNA polymerase. The PCR product was cloned into pJET1.2/blunt cloning vector. The recombinant vector (pJETε) was sequenced using universal primers. At the next step epsilon toxin gene was subcloned into pET22b(+) expression vector and transformed into E. coli Rosetta (DE3) host strain. The recombinant protein has been expressed in E. coli Rosetta (DE3) cells after subcloning of C. perfringens etx gene (1008 bp) into the expression vector. We concluded that E. coli Rosetta strain was suitable for the expression of recombinant C. perfringens epsilon toxin protein from pET22ε expression vector. This recombinant cell can be used for further research on recombinant vaccine development.

  7. Tradeoff between reproduction and resistance evolution to Bt-toxin in Helicoverpa armigera: regulated by vitellogenin gene expression.

    Science.gov (United States)

    Zhang, W N; Xiao, H J; Liang, G M; Guo, Y Y; Wu, K M

    2014-08-01

    Evolution of resistance to insecticides usually has fitness tradeoffs associated with adaptation to the stress. The basic regulation mechanism of tradeoff between reproduction and resistance evolution to Bacillus thuringiensis (Bt) toxin in the cotton bollworm, Helicoverpa armigera (Ha), based on the vitellogenin (Vg) gene expression was analyzed here. The full-length cDNA of the Vg gene HaVg (JX504706) was cloned and identified. HaVg has 5704 base pairs (bp) with an open reading frame (ORF) of 5265 bp, which encoded 1756 amino acid protein with a predicted molecular mass of 197.28 kDa and a proposed isoelectric point of 8.74. Sequence alignment analysis indicated that the amino acid sequence of HaVg contained all of the conserved domains detected in the Vgs of the other insects and had a high similarity with the Vgs of the Lepidoptera insects, especially Noctuidae. The resistance level to Cry1Ac Bt toxin and relative HaVg mRNA expression levels among the following four groups: Cry1Ac-susceptible strain (96S), Cry1Ac-resistant strain fed on artificial diet with Bt toxin for 135 generations (BtR stands for the Cry1Ac Bt resistance), progeny of the Cry1Ac-resistant strain with a non-Bt-toxin artificial diet for 38 generations (CK1) and the direct descendants of the 135th-generation resistant larvae which were fed on an artificial diet without the Cry1Ac protein (CK2) were analyzed. Compared with the 96S strain, the resistance ratios of the BtR strain, the CK1 strain and the CK2 strain were 2917.15-, 2.15- and 2037.67-fold, respectively. The maximum relative HaVg mRNA expression levels of the BtR strain were approximately 50% less than that of the 96S strain, and the coming of maximum expression was delayed for approximately 4 days. The overall trend of the HaVg mRNA expression levels in the CK1 strain was similar to that in the 96S strain, and the overall trend of the HaVg mRNA expression levels in the CK2 strain was similar to that in the BtR strain. Our results

  8. Detection of virulence, antibiotic resistance and toxin (VAT) genes in Campylobacter species using newly developed multiplex PCR assays.

    Science.gov (United States)

    Laprade, Natacha; Cloutier, Michel; Lapen, David R; Topp, Edward; Wilkes, Graham; Villemur, Richard; Khan, Izhar U H

    2016-05-01

    Campylobacter species are one of the leading causes of bacterial gastroenteritis in humans worldwide. This twofold study was sought to: i) develop and optimize four single-tube multiplex PCR (mPCR) assays for the detection of six virulence (ciaB, dnaJ, flaA, flaB, pldA and racR), three toxin (cdtA, cdtB and cdtC) and one antibiotic resistance tet(O) genes in thermophilic Campylobacter spp. and ii) apply and evaluate the developed mPCR assays by testing 470 previously identified C. jejuni, C. coli and C. lari isolates from agricultural water. In each mPCR assay, a combination of two or three sets of primer pairs for virulence, antibiotic resistance and toxin (VAT) genes was used and optimized. Assay 1 was developed for the detection of dnaJ, racR and cdtC genes with expected amplification sizes of 720, 584 and 182bp. Assay 2 generated PCR amplicons for tet(O) and cdtA genes of 559 and 370bp. Assay 3 amplified cdtB ciaB, and pldA genes with PCR amplicon sizes of 620, 527 and 385bp. Assay 4 was optimized for flaA and flaB genes that generated PCR amplicons of 855 and 260bp. The primer pairs and optimized PCR protocols did not show interference and/or cross-amplification with each other and generated the expected size of amplification products for each target VAT gene for the C. jejuni ATCC 33291 reference strain. Overall, all ten target VAT genes were detected at a variable frequency in tested isolates of thermophilic Campylobacter spp. where cdtC, flaB, ciaB, cdtB, cdtA and pldA were commonly detected compared to the flaA, racR, dnaJ and tet(O) genes which were detected with less frequency. The developed mPCR assays are simple, rapid, reliable and sensitive tools for simultaneously assessing potential pathogenicity and antibiotic resistance profiling in thermophilic Campylobacter spp. The mPCR assays will be useful in diagnostic and analytical settings for routine screening of VAT characteristics of Campylobacter spp. as well as being applicable in epidemiological

  9. TetR Is a Positive Regulator of the Tetanus Toxin Gene in Clostridium tetani and Is Homologous to BotR

    NARCIS (Netherlands)

    Marvaud, Jean-Christophe; Eisel, Ulrich; Binz, Thomas; Niemann, Heiner; Popoff, Michel R.

    1998-01-01

    The TetR gene immediately upstream from the tetanus toxin (TeTx) gene was characterized. It encodes a 21,562-Da protein which is related (50 to 65% identity) to the equivalent genes (botR) in Clostridium botulinum. TetR has the feature of a DNA binding protein with a basic pI (9.53). It contains a

  10. Cryptanalysis of C2

    DEFF Research Database (Denmark)

    Borghoff, Julia; Knudsen, Lars Ramkilde; Leander, Gregor

    2009-01-01

    We present several attacks on the block cipher C2, which is used for encrypting DVD Audio discs and Secure Digital cards. C2 has a 56 bit key and a secret 8 to 8 bit S-box. We show that if the attacker is allowed to choose the key, the S-box can be recovered in 2^24 C2 encryptions. Attacking the ...... bit key for a known S-box can be done in complexity 2^48. Finally, a C2 implementation with a 8 to 8 bit secret S-box (equivalent to 2048 secret bits) and a 56 bit secret key can be attacked in 2^53.5 C2 encryptions on average....

  11. Association of cytolethal distending toxin-II gene-positive Escherichia coli with Escherichia albertii, an emerging enteropathogen.

    Science.gov (United States)

    Hinenoya, Atsushi; Yasuda, Noritomo; Mukaizawa, Natsuko; Sheikh, Sikander; Niwa, Yuko; Awasthi, Sharda Prasad; Asakura, Masahiro; Tsukamoto, Teizo; Nagita, Akira; Albert, M John; Yamasaki, Shinji

    2017-12-01

    Cytolethal distending toxin (CDT)-producing Escherichia coli have been isolated from patients with diarrhea, sepsis and urinary tract infection. CDT of E. coli is divided into five types (CDT-I through CDT-V) based on differences in amino acid sequences and its genomic location. However, in our recent studies, a few strains of cdt-II gene-positive bacteria, initially identified as atypical E. coli, were re-identified as Escherichia albertii, an emerging enteropathogen, by extensive characterization including multilocus sequence (MLS) analysis and sugar utilization tests. This finding prompted us to investigate if bacteria previously identified as cdt-II gene-positive E. coli might be E. albertii. In the present study, we therefore re-examined the identity of 20 cdt-II gene-positive bacteria isolated from children with diarrhea, which were initially identified as atypical E. coli. By extensive sugar utilization tests, these bacteria showed a closer relatedness to E. albertii than E. coli, because they did not ferment any of the tested sugars including dulcitol, lactose, d-melibiose, l-rhamnose and d-xylose. Further, both phylogenetic analyses based on nucleotide sequences of 7 housekeeping genes (MLS analysis) and rpoB gene showed that all the cdt-II gene-positive bacteria belonged to a distinct lineage of E. albertii from those of E. coli and Shigella boydii. They were also positive by an E. albertii-specific PCR. Taken together, these data suggest that cdt-II gene-positive bacteria previously identified as E. coli are actually E. albertii. Therefore, we suggest a new definition for cdt-II gene-positive E. coli as E. albertii with the inclusion of CDT-II in E. albertii CDT. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Stool C difficile toxin

    Science.gov (United States)

    Antibiotic associated colitis - toxin; Colitis - toxin; Pseudomembranous - toxin; Necrotizing colitis - toxin; C difficile - toxin ... not recently taken antibiotics. This condition is called pseudomembranous colitis .

  13. A longevity assurance gene homolog of tomato mediates resistance to Alternaria alternata f. sp. lycopersici toxins and fumonisin B1

    NARCIS (Netherlands)

    Brandwagt, Bas F.; Mesbah, Laurent A.; Takken, Frank L.W.; Laurent, Pascal L.; Kneppers, Tarcies J.A.; Hille, Jacques; Nijkamp, H. John J.

    2000-01-01

    The phytopathogenic fungus Alternaria alternata f. sp. lycopersici (AAL) produces toxins that are essential for pathogenicity of the fungus on tomato (Lycopersicon esculentum). AAL toxins and fumonisins of the unrelated fungus Fusarium moniliforme are sphinganine-analog mycotoxins (SAMs), which

  14. Shiga toxin and beta-lactamases genes in Escherichia coli phylotypes isolated from carcasses of broiler chickens slaughtered in Iran.

    Science.gov (United States)

    Bagheri, Mahboube; Ghanbarpour, Reza; Alizade, Hesam

    2014-05-02

    Two hundred and four Escherichia coli strains were isolated from external and visceral cavity surfaces of 102 slaughtered broiler carcasses. The isolates were screened to determine the phylogenetic background and presence of Shiga toxins (stx1, stx2), intimin (eae) and beta-lactamase (blaTEM, blaSHV) genes. Phylotyping results revealed that the E. coli isolates segregated in four phylogenetic groups A (56.86%), B1 (19.12%), B2 (4.90%) and D (19.12%). PCR assays revealed that 13 isolates (6.37%) from 12 carcasses were positive for eae (12 isolates) and/or stx2 (2) genes. The eae positive isolates belonged to phylogenetic groups A (A0, A1), B1, B2 (B22) and D (D2). Two stx2 positive and seven eae positive isolates were recovered from visceral cavity surface, whereas only 5 eae positive isolates were from the external surface of the carcasses. On the other hand, thirty one E. coli strains isolated from visceral cavity and external surface of 26 carcasses carried the blaTEM (27) and blaSHV (4) genes and belonged to different phylo-groups. This study suggests that broiler carcasses could be considered as an important source of EPEC and STEC pathotypes in southeast of Iran; as well as the examined antibiotic resistance genes, which were carried by some isolates and could be transferred to pathogens through the food chain. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Point-of-care and visual detection of P. aeruginosa and its toxin genes by multiple LAMP and lateral flow nucleic acid biosensor.

    Science.gov (United States)

    Chen, Yuting; Cheng, Nan; Xu, Yuancong; Huang, Kunlun; Luo, Yunbo; Xu, Wentao

    2016-07-15

    This study describes a simple and sensitive approach for visual and point-of-care detection of P. aeruginosa and its toxin genes based on multiple loop-mediated isothermal amplification (mLAMP) and lateral flow nucleic acid biosensor (LFNAB). Differentiation of the internal standard gene ecfX and toxin genes (ExoS and ExoU) in P. aeruginosa was determined using FITC-, hex-and digoxin-modified primers in the mLAMP process. In the presence of biotin-and FITC- (hex-, digoxin-) modified primers and Bst DNA polymerase large fragments, the mLAMP produced numerous biotin- and FITC- (hex-, digoxin-) attached duplex DNA products. The products were detected by LFNAB through dual immunoreactions (anti-biotin antibodies on the gold nanoparticle (Au-NP) and biotin on the duplex, anti-FITC (hex, digoxin) antibodies on the LFNAB test line and FITC (hex, digoxin) on the duplex). The accumulation of Au-NPs produced a characteristic red band, enabling visual detection of P. aeruginosa and its toxin genes without instrumentation. After systematic optimization of LFNAB preparation and detecting conditions, the current approach was capable of detecting concentrations as low as 20 CFU/mL P. aeruginosa or its toxin genes within 50min without complicated instrument, which is more sensitive than PCR. Therefore, this approach provides a simple, pollution free, sensitive, and low-cost point-of-care test for the detection of P. aeruginosa and its toxin genes. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. cDNAs of aminopeptidase-like protein genes from Plodia interpunctella strains with different susceptibilities to Bacillus thuringiensis toxins.

    Science.gov (United States)

    Zhu, Y C; Kramer, K J; Oppert, B; Dowdy, A K

    2000-03-01

    Aminopeptidase N has been reported to be a Bacillus thuringiensis (Bt) Cry1A toxin-binding protein in several lepidopteran insects. cDNAs of aminopeptidase-like proteins from both Bt-susceptible RC688s and Bt-resistant HD198r strains of the Indianmeal moth, Plodia interpunctella, were cloned and sequenced. They contain 3345 and 3358 nucleotides, respectively, and each has a 3048 bp open reading frame that encodes 1016 amino acids. Putative protein sequences include 10 potential glycosylation sites and a zinc metal binding site motif of HEXXH, which is typical of the active site of zinc-dependent metallopeptidases. Sequence analysis indicated that the deduced protein sequences are most similar to an aminopeptidase from Heliothis virescens with 62% sequence identity and highly similar to three other lepidopteran aminopeptidases from Plutella xylostella, Manduca sexta, Bombyx mori with sequence identities of 51-52%. Four nucleotide differences were observed in the open reading frames that translated into two amino acid differences in the putative protein sequences. Polymerase chain reaction (PCR) confirmed an aminopeptidase gene coding difference between RC688s and HD198r strains of P. interpunctella in the PCR amplification of a specific allele (PASA) using preferential primers designed from a single base substitution. The gene mutation for Asp185-->Glu185 was also confirmed in two additional Bt-resistant P. interpunctella strains. This mutation is located within a region homologous to the conserved Cry1Aa toxin binding regions from Bombyx mori and Plutella xylostella. The aminopeptidase-like mRNA expression levels in the Bt-resistant strain were slightly higher than those in the Bt-susceptible strain. The sequences reported in this paper have been deposited in the GenBank database (accession numbers AF034483 for susceptible strain RC688s and AF034484 for resistant strain HD198r).

  17. Disruption of diphthamide synthesis genes and resulting toxin resistance as a robust technology for quantifying and optimizing CRISPR/Cas9-mediated gene editing.

    Science.gov (United States)

    Killian, Tobias; Dickopf, Steffen; Haas, Alexander K; Kirstenpfad, Claudia; Mayer, Klaus; Brinkmann, Ulrich

    2017-11-13

    We have devised an effective and robust method for the characterization of gene-editing events. The efficacy of editing-mediated mono- and bi-allelic gene inactivation and integration events is quantified based on colony counts. The combination of diphtheria toxin (DT) and puromycin (PM) selection enables analyses of 10,000-100,000 individual cells, assessing hundreds of clones with inactivated genes per experiment. Mono- and bi-allelic gene inactivation is differentiated by DT resistance, which occurs only upon bi-allelic inactivation. PM resistance indicates integration. The robustness and generalizability of the method were demonstrated by quantifying the frequency of gene inactivation and cassette integration under different editing approaches: CRISPR/Cas9-mediated complete inactivation was ~30-50-fold more frequent than cassette integration. Mono-allelic inactivation without integration occurred >100-fold more frequently than integration. Assessment of gRNA length confirmed 20mers to be most effective length for inactivation, while 16-18mers provided the highest overall integration efficacy. The overall efficacy was ~2-fold higher for CRISPR/Cas9 than for zinc-finger nuclease and was significantly increased upon modulation of non-homologous end joining or homology-directed repair. The frequencies and ratios of editing events were similar for two different DPH genes (independent of the target sequence or chromosomal location), which indicates that the optimization parameters identified with this method can be generalized.

  18. Toxin-Resistant Sodium Channels: Parallel Adaptive Evolution across a Complete Gene Family

    National Research Council Canada - National Science Library

    Jost, Manda Clair; Hillis, David M; Lu, Ying; Kyle, John W; Fozzard, Harry A; Zakon, Harold H

    2008-01-01

    Approximately 75% of vertebrate proteins belong to protein families encoded by multiple evolutionarily related genes, a pattern that emerged as a result of gene and genome duplications over the course of vertebrate evolution...

  19. A PCR-RFLP assay to detect and type cytolethal distending toxin (cdt) genes in Campylobacter hyointestinalis.

    Science.gov (United States)

    Hatanaka, Noritoshi; Kamei, Kazumasa; Somroop, Srinuan; Awasthi, Sharda Prasad; Asakura, Masahiro; Misawa, Naoaki; Hinenoya, Atsushi; Yamasaki, Shinji

    2017-02-14

    Campylobacter hyointestinalis is considered as an emerging zoonotic pathogen. We have recently identified two types of cytolethal distending toxin (cdt) gene in C. hyointestinalis and designated them as Chcdt-I and Chcdt-II. In this study, we developed a PCR-restriction fragment length polymorphism (RFLP) assay that can differentiate Chcdt-I from Chcdt-II. When the PCR-RFLP assay was applied to 17 other Campylobacter strains and 25 non-Campylobacter strains, PCR products were not obtained irrespective of their cdt gene-possession, indicating that the specificity of the PCR-RFLP assay was 100%. In contrast, when the PCR-RFLP assay was applied to 35 C. hyointestinalis strains including 23 analyzed in the previous study and 12 newly isolated from pigs and bovines, all of them showed the presence of cdt genes. Furthermore, a restriction digest by EcoT14-I revealed that 29 strains contained both Chcdt-I and Chcdt-II and 6 strains contained only Chcdt-II, showing 100% sensitivity. Unexpectedly, however, PCR products obtained from 7 C. hyointestinalis strains were not completely digested by EcoT14-I. Nucleotide sequence analysis revealed that the undigested PCR product was homologous to cdtB but not to Chcdt-IB or Chcdt-IIB, indicating the presence of another cdt gene-variant. Then, we further digested the PCR products with DdeI in addition to EcoT14-I, showing that all three cdt genes, including a possible new Chcdt variant, could be clearly differentiated. Thus, the PCR-RFLP assay developed in this study is a valuable tool for evaluating the Chcdt gene-profile of bacteria.

  20. Cereulide synthetase gene cluster from emetic Bacillus cereus: Structure and location on a mega virulence plasmid related to Bacillus anthracis toxin plasmid pXO1

    Directory of Open Access Journals (Sweden)

    Wagner Martin

    2006-03-01

    Full Text Available Abstract Background Cereulide, a depsipeptide structurally related to valinomycin, is responsible for the emetic type of gastrointestinal disease caused by Bacillus cereus. Recently, it has been shown that this toxin is produced by a nonribosomal peptide synthetase (NRPS, but its exact genetic organization and biochemical synthesis is unknown. Results The complete sequence of the cereulide synthetase (ces gene cluster, which encodes the enzymatic machinery required for the biosynthesis of cereulide, was dissected. The 24 kb ces gene cluster comprises 7 CDSs and includes, besides the typical NRPS genes like a phosphopantetheinyl transferase and two CDSs encoding enzyme modules for the activation and incorporation of monomers in the growing peptide chain, a CDS encoding a putative hydrolase in the upstream region and an ABC transporter in the downstream part. The enzyme modules responsible for incorporation of the hydroxyl acids showed an unusual structure while the modules responsible for the activation of the amino acids Ala and Val showed the typical domain organization of NRPS. The ces gene locus is flanked by genetic regions with high homology to virulence plasmids of B. cereus, Bacillus thuringiensis and Bacillus anthracis. PFGE and Southern hybridization showed that the ces genes are restricted to emetic B. cereus and indeed located on a 208 kb megaplasmid, which has high similarities to pXO1-like plasmids. Conclusion The ces gene cluster that is located on a pXO1-like virulence plasmid represents, beside the insecticidal and the anthrax toxins, a third type of B. cereus group toxins encoded on megaplasmids. The ces genes are restricted to emetic toxin producers, but pXO1-like plasmids are also present in emetic-like strains. These data might indicate the presence of an ancient plasmid in B. cereus which has acquired different virulence genes over time. Due to the unusual structure of the hydroxyl acid incorporating enzyme modules of Ces

  1. Deletion of a MFS transporter-like gene in Cercospora nicotianae reduces cercosporin toxin accumulation and fungal virulence.

    Science.gov (United States)

    Choquer, Mathias; Lee, Miin-Huey; Bau, Huey-Jiunn; Chung, Kuang-Ren

    2007-02-06

    Many phytopathogenic Cercospora species produce a host-nonselective polyketide toxin, called cercosporin, whose toxicity exclusively relies on the generation of reactive oxygen species. Here, we describe a Cercospora nicotianae CTB4 gene that encodes a putative membrane transporter and provide genetic evidence to support its role in cercosporin accumulation. The predicted CTB4 polypeptide has 12 transmembrane segments with four conserved motifs and has considerable similarity to a wide range of transporters belonging to the major facilitator superfamily (MFS). Disruption of the CTB4 gene resulted in a mutant that displayed a drastic reduction of cercosporin production and accumulation of an unknown brown pigment. Cercosporin was detected largely from fungal hyphae of ctb4 disruptants, but not from the surrounding medium, suggesting that the mutants were defective in both cercosporin biosynthesis and secretion. Cercosporin purified from the ctb4 disruptants exhibited toxicity to tobacco suspension cells, insignificantly different from wild-type, whereas the disruptants formed fewer lesions on tobacco leaves. The ctb4 null mutants retained normal resistance to cercosporin and other singlet oxygen-generating photosensitizers, indistinguishable from the parental strain. Transformation of a functional CTB4 clone into a ctb4 null mutant fully revived cercosporin production. Thus, we propose that the CTB4 gene encodes a putative MFS transporter responsible for secretion and accumulation of cercosporin.

  2. [Protein toxins of Staphylococcus aureus].

    Science.gov (United States)

    Shamsutdinov, A F; Tiurin, Iu A

    2014-01-01

    Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.

  3. Expression pattern of three-finger toxin and phospholipase A2 genes in the venom glands of two sea snakes, Lapemis curtus and Acalyptophis peronii: comparison of evolution of these toxins in land snakes, sea kraits and sea snakes

    Science.gov (United States)

    Pahari, Susanta; Bickford, David; Fry, Bryan G; Kini, R Manjunatha

    2007-01-01

    Background Snake venom composition varies widely both among closely related species and within the same species, based on ecological variables. In terrestrial snakes, such variation has been proposed to be due to snakes' diet. Land snakes target various prey species including insects (arthropods), lizards (reptiles), frogs and toads (amphibians), birds (aves), and rodents (mammals), whereas sea snakes target a single vertebrate class (fishes) and often specialize on specific types of fish. It is therefore interesting to examine the evolution of toxins in sea snake venoms compared to that of land snakes. Results Here we describe the expression of toxin genes in the venom glands of two sea snakes, Lapemis curtus (Spine-bellied Sea Snake) and Acalyptophis peronii (Horned Sea Snake), two members of a large adaptive radiation which occupy very different ecological niches. We constructed cDNA libraries from their venom glands and sequenced 214 and 192 clones, respectively. Our data show that despite their explosive evolutionary radiation, there is very little variability in the three-finger toxin (3FTx) as well as the phospholipase A2 (PLA2) enzymes, the two main constituents of Lapemis curtus and Acalyptophis peronii venom. To understand the evolutionary trends among land snakes, sea snakes and sea kraits, pairwise genetic distances (intraspecific and interspecific) of 3FTx and PLA2 sequences were calculated. Results show that these proteins appear to be highly conserved in sea snakes in contrast to land snakes or sea kraits, despite their extremely divergent and adaptive ecological radiation. Conclusion Based on these results, we suggest that streamlining in habitat and diet in sea snakes has possibly kept their toxin genes conserved, suggesting the idea that prey composition and diet breadth may contribute to the diversity and evolution of venom components. PMID:17900344

  4. Incidence, Antimicrobial Susceptibility, and Toxin Genes Possession Screening of Staphylococcus aureus in Retail Chicken Livers and Gizzards

    Directory of Open Access Journals (Sweden)

    Lubna S. Abdalrahman

    2015-04-01

    Full Text Available Few recent outbreaks in Europe and the US involving Campylobacter and Salmonella were linked to the consumption of chicken livers. Studies investigating Staphylococcus aureus in chicken livers and gizzards are very limited. The objectives of this study were to determine the prevalence, antimicrobial resistance, and virulence of S. aureus and MRSA (Methicillin-Resistant Staphylococcus aureus in retail chicken livers and gizzards in Tulsa, Oklahoma. In this study, 156 chicken livers and 39 chicken gizzards samples of two brands were collected. While one of the brands showed very low prevalence of 1% (1/100 for S. aureus in chicken livers and gizzards, the second brand showed prevalence of 37% (31/95. No MRSA was detected since none harbored the mecA or mecC gene. Eighty seven S. aureus isolates from livers and 28 from gizzards were screened for antimicrobial resistance to 16 antimicrobials and the possession of 18 toxin genes. Resistance to most of the antimicrobials screened including cefoxitin and oxacillin was higher in the chicken gizzards isolates. While the prevalence of enterotoxin genes seg and sei was higher in the gizzards isolates, the prevalence of hemolysin genes hla, hlb, and hld was higher in the livers ones. The lucocidin genes lukE-lukD was equally prevalent in chicken livers and gizzards isolates. Using spa typing, a subset of the recovered isolates showed that they are not known to be livestock associated and, hence, may be of a human origin. In conclusion, this study stresses the importance of thorough cooking of chicken livers and gizzards since it might contain multidrug resistant enterotoxigenic S. aureus. To our knowledge this is the first study to specifically investigate the prevalence of S. aureus in chicken livers and gizzards in the US.

  5. Molecular cloning, nucleotide sequence, and expression in Escherichia coli of a hemolytic toxin (aerolysin) gene from Aeromonas trota.

    Science.gov (United States)

    Khan, A A; Kim, E; Cerniglia, C E

    1998-07-01

    Aeromonas trota AK2, which was derived from ATCC 49659 and produces the extracellular pore-forming hemolytic toxin aerolysin, was mutagenized with the transposon mini-Tn5Km1 to generate a hemolysin-deficient mutant, designated strain AK253. Southern blotting data indicated that an 8.7-kb NotI fragment of the genomic DNA of strain AK253 contained the kanamycin resistance gene of mini-Tn5Km1. The 8.7-kb NotI DNA fragment was cloned into the vector pGEM5Zf(-) by selecting for kanamycin resistance, and the resultant clone, pAK71, showed aerolysin activity in Escherichia coli JM109. The nucleotide sequence of the aerA gene, located on the 1.8-kb ApaI-EcoRI fragment, was determined to consist of 1,479 bp and to have an ATG initiation codon and a TAA termination codon. An in vitro coupled transcription-translation analysis of the 1.8-kb region suggested that the aerA gene codes for a 54-kDa protein, in agreement with nucleotide sequence data. The deduced amino acid sequence of the aerA gene product of A. trota exhibited 99% homology with the amino acid sequence of the aerA product of Aeromonas sobria AB3 and 57% homology with the amino acid sequences of the products of the aerA genes of Aeromonas salmonicida 17-2 and A. sobria 33.

  6. Molecular cloning, nucleotide sequence, and expression in Escherichia coli of a hemolytic toxin (aerolysin) gene from Aeromonas trota

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A.A.; Kim, E.; Cerniglia, C.E. [Food and Drug Administration, Jefferson, AR (United States). National Center for Toxicological Research

    1998-07-01

    Aeromonas trota AK2, which was derived from ATCC 49659 and produces the extracellular pore-forming hemolytic toxin aerolysin, was mutagenized with the transposon mini-Tn5Km1 to generate a hemolysin-deficient mutant, designated strain AK253. Southern blotting data indicated that an 8.7-kb NotI fragment of the genomic DNA of strain AK253 contained the kanamycin resistance gene of mini-Tn5Km1. The 8.7-kb NotI DNA fragment was cloned into the vector pGEM5Zf({minus}) by selecting for kanamycin resistance, and the resultant clone, pAK71, showed aerolysin activity in Escherichia coli JM109. The nucleotide sequence of the aerA gene, located on the 1.8-kb ApaI-EcoRI fragment, was determined to consist of 1,479 bp and to have an ATG initiation codon and a TAA termination codon. An in vitro coupled transcription-translation analysis of the 1.8-kb region suggested that the aerA gene codes for a 54-kDa protein, in agreement with nucleotide sequence data. The deduced amino acid sequence of the aerA gene product of A. trota exhibited 99% homology with the amino acid sequence of the aerA product of Aeromonas sobria AB3 and 57% homology with the amino acid sequences of the products of the aerA genes of Aeromonas salmonicida 17-2 and A. sobria 33.

  7. C2-mediated decrease in DNA methylation, accumulation of siRNAs, and increase in expression for genes involved in defense pathways in plants infected with beet severe curly top virus.

    Science.gov (United States)

    Yang, Li-Ping; Fang, Yuan-Yuan; An, Chun-Peng; Dong, Li; Zhang, Zhong-Hui; Chen, Hao; Xie, Qi; Guo, Hui-Shan

    2013-03-01

    Cytosine methylation is one of epigenetic information marked on the DNA sequence. In plants, small interfering RNAs (siRNAs) target homologous genomic DNA sequences for cytosine methylation. This process, known as RNA-directed DNA methylation (RdDM), plays an important role in transposon control, regulation of gene expression and virus resistance. In this paper, we demonstrate that the C2 protein encoded by a geminivirus (beet severe curly top virus, BSCTV) mediated a decrease in DNA methylation of repeat regions in the promoters of ACD6, an upstream regulator of the salicylic acid defense pathway, and GSTF14, an endogenous gene of the glutathione S-transferase superfamily that is implicated in numerous stress responses. C2-mediated decreases in DNA methylation reduced accumulation of the siRNAs derived from the promoter repeats and enhanced the steady-state expression of both ACD6 and GSTF14 transcripts. Reduced accumulation of BSCTV-derived siRNAs was detected in BSCTV-infected plants, but not in plants infected with C2-deficient BSCTV (c2(- ) BSCTV). C2 protein exhibited no siRNA-binding activity. Instead, our results revealed that C2 protein-mediated decreases in DNA methylation appeared to affect the production of siRNAs that are required for targeting and reinforcing RdDM, a process that activated expression of defense-related genes that are normally dampened by these siRNAs in the host plants. However, C2-dependent reduction in virus-derived siRNAs also benefits the viruses by disrupting the feedback loop reinforcing DNA methylation-mediated antiviral silencing. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  8. Small and Smaller—sRNAs and MicroRNAs in the Regulation of Toxin Gene Expression in Prokaryotic Cells: A Mini-Review

    Science.gov (United States)

    Bloch, Sylwia; Węgrzyn, Alicja; Węgrzyn, Grzegorz; Nejman-Faleńczyk, Bożena

    2017-01-01

    Non-coding small RNAs (sRNAs) have been identified in the wide range of bacteria (also pathogenic species) and found to play an important role in the regulation of many processes, including toxin gene expression. The best characterized prokaryotic sRNAs regulate gene expression by base pairing with mRNA targets and fall into two broad classes: cis-encoded sRNAs (also called antisense RNA) and trans-acting sRNAs. Molecules from the second class are frequently considered as the most related to eukaryotic microRNAs. Interestingly, typical microRNA-size RNA molecules have also been reported in prokaryotic cells, although they have received little attention up to now. In this work we have collected information about all three types of small prokaryotic RNAs in the context of the regulation of toxin gene expression. PMID:28556797

  9. Small and Smaller-sRNAs and MicroRNAs in the Regulation of Toxin Gene Expression in Prokaryotic Cells: A Mini-Review.

    Science.gov (United States)

    Bloch, Sylwia; Węgrzyn, Alicja; Węgrzyn, Grzegorz; Nejman-Faleńczyk, Bożena

    2017-05-30

    Non-coding small RNAs (sRNAs) have been identified in the wide range of bacteria (also pathogenic species) and found to play an important role in the regulation of many processes, including toxin gene expression. The best characterized prokaryotic sRNAs regulate gene expression by base pairing with mRNA targets and fall into two broad classes: cis -encoded sRNAs (also called antisense RNA) and trans -acting sRNAs. Molecules from the second class are frequently considered as the most related to eukaryotic microRNAs. Interestingly, typical microRNA-size RNA molecules have also been reported in prokaryotic cells, although they have received little attention up to now. In this work we have collected information about all three types of small prokaryotic RNAs in the context of the regulation of toxin gene expression.

  10. Prevalence of shiga toxin-producing Escherichia coli stx1, stx2, eaeA, and rfbE genes and survival of E. coli O157:H7 in manure from organic and low-input conventional dairy farms

    NARCIS (Netherlands)

    Franz, E.; Klerks, M.M.; Vos, de O.J.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2007-01-01

    Manure samples were collected from 16 organic (ORG) and 9 low-input conventional (LIC) Dutch dairy farms during August and September 2004 to determine the prevalence of the STEC virulence genes stx(1) (encoding Shiga toxin 1), stx(2) (encoding Shiga toxin 2), and eaeA (encoding intimin), as well as

  11. C2 Agility

    DEFF Research Database (Denmark)

    Mitchell, Dr. William; Alberts, David S.; Bernier, Francois

    Agility is the capability to successfully effect, cope with, and/or exploit changes in circumstances. While other factors will also influence outcomes, C2 Agility enables entities to effectively and efficiently employ the resources they have in a timely manner in a variety of missions and circums...

  12. New variants of lepidoptericidal toxin genes encoding Bacillus thuringiensis Vip3Aa proteins.

    Science.gov (United States)

    Sauka, Diego H; Rodriguez, Sonia E; Benintende, Graciela B

    2012-01-01

    Bacillus thuringiensis is an entomopathogenic bacterium characterized by producing parasporal proteinaceous insecticidal crystal inclusions during sporulation. Many strains are capable of also expressing other insecticidal proteins called Vip during the vegetative growing phase. Particularly, Vip3A proteins have activity against certain Lepidoptera species through a unique mechanism of action which emphasized their possible use in resistance management strategies against resistant pests. The aim of the work was to develop a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method that can distinguish between vip3A genes from B. thuringiensis strains. In addition, 4 novel vip3Aa genes were cloned and sequenced. The method was originally based on amplification of a single PCR amplicon and the use of 2 restriction enzymes with recognition sites that facilitate simultaneous detection. Subsequently, a third restriction enzyme was used to distinguish between vip3A variants. Thirteen vip3Aa genes were identified in strains belonging to 10 different B. thuringiensis serovars. Three intra-subclass variants of vip3Aa genes could be differentiated. The presented method can serve as an invaluable tool for the investigation of known and novel vip3A genes in B. thuringiensis strains. To the best of our knowledge, this is the first report where variants of a same subclass of insecticidal genes could be distinguished following PCR-RFLP. Copyright © 2013 S. Karger AG, Basel.

  13. Prevalence of toxin genes among the clinical isolates of Staphylococcus aureus and its clinical impact

    Directory of Open Access Journals (Sweden)

    Divya Deodhar

    2015-01-01

    Full Text Available Introduction: Staphylococcus aureus (S. aureus causes a variety of infections, ranging from a mild skin infection to blood stream infections and deep seated infections. As Stapylococcus aureus bacteremia (SAB has the tendency to cause endovascular and metastatic infections, complications can occur at almost all sites of the body. Hence, SAB is associated with increased morbidity and mortality in spite of appropriate antimicrobial treatment. The virulence in S. aureus is determined by the presence of adhesins and toxins, which behave like superantigens (SAgs and leads to a massive release of proinflammatory cytokines causing overwhelming inflammatory response leading to endothelial leakage, hemodynamic shock, multiorgan failure, and possibly death. Materials and Methods: One year prospective study conducted in a tertiary care hospital in southern part of India included all patients with SAB. Clinical details were filled according to. All isolates were subjected to polymerase chain reaction (PCR for enterotoxin profiling. Results: A total of 101 patients of SAB were identified which comprises of 61 (60.4% patients with methicillin-susceptible S. aureus (MSSA and 40 (39.6% patients with methicillin-resistant S. aureus (MRSA. Most common predictors of mortality were prior hospitalization and antibiotic intake, severe organ dysfunction, shock, tachycardia, and leukocytosis. Two-third of the isolates had at least one enterotoxin, most prevalent was sea; 28% and 27% (P - value = 0.001 MSSA isolates had seg and sei; whereas, 38.6% (P - value < 0.001 of MRSA isolates were found to have sea. The most common enterotoxin associated with mortality was sei, which comprised of 38% of all mortality. Conclusion: In SAB, the significant predictors of mortality were prior hospitalization and antibiotic intake, presence of multiorgan dysfunction, and shock. Although overall significance between the enterotoxin and shock could not be demonstrated, it successfully

  14. Molecular investigation of tRNA genes integrity and its relation to pathogenicity islands in Shiga toxin-producing Escherichia coli (STEC) strains

    OpenAIRE

    Novais,Rogério Carlos; Chaves,Marcela Cassin; Gonzalez,Alice Gonçalves Martins; Andrade,João Ramos Costa

    2004-01-01

    tRNA genes are known target sites for the integration of pathogenicity islands (PAI) and other genetic elements, such as bacteriophages, into bacterial genome. In most STEC (Shiga toxin-producing Escherichia coli), the PAI called LEE (locus of enterocyte effacement) is related to bacterial virulence and is mostly associated to the tRNA genes selC and pheU. In this work, we first investigated the relationship of LEE with tRNA genes selC and pheU in 43 STEC strains. We found that 28 strains (65...

  15. [Establishment of a triplex real-time PCR for the detection of cholera toxin gene ctx and heat labile enterotoxin gene elt].

    Science.gov (United States)

    Li, Jie; Kan, Biao; Zhang, Jingyun

    2014-06-01

    To establish a triplex TaqMan real-time PCR system containing internal amplification control (IAC) to detect cholera toxin gene ctxA and enterotoxigenic Escherichia coli (ETEC)heat-labile enterotoxin gene elt. Primers and probes were designed based on the sequences of ctxA, elt and IAC. Both sensitivity and specificity were analyzed and interactions between different reactions were evaluated. This system showed that the sensitivity of ctxA was 94 copies/reaction while the elt 79 copies/reaction and the amplification efficiency were 94.7% and 98.1%, respectively. Under the ratio of copy numbers on gene ctxA to elt as between 1 : 1-1 : 10, when both targets were detected, with impact was less on each other. However, when the amount of elt or ctxA was 100 times of IAC, the amplification of IAC was significantly inhibited. This system showed both satisfactory sensitivity and specificity, thus could be used to detect pathogenic bacteria in diarrhea stools. The detection of IAC could prompt the presence of PCR inhibitors in samples being tested.

  16. Gene detection and toxin production evaluation of hemolysin BL of Bacillus cereus isolated from milk and dairy products marketed in Brazil

    Directory of Open Access Journals (Sweden)

    Andre L.S. Reis

    2013-12-01

    Full Text Available Bacillus cereusis an ubiquitous, spore-forming bacteria that can survive pasteurization and the majority of the heating processes used in the dairy industry. Besides, it is a pathogen responsible for different types of food poisoning. One type of foodborne disease caused by B.cereusis the diarrheal syndrome, which is caused by the ingestion of vegetative cells producing toxins in the small intestine. One virulence factor for the diarrheal syndrome is the toxin hemolysin BL (HBL, a three-component protein formed by the L1, L2 and B components. In order to evaluate the presence of diarrheal strains isolated from milk and dairy products, 63 B. cereus isolates were obtained from 260 samples of UHT milk, pasteurized milk and powdered milk, sold in commercial establishments and from different brands. The isolates were subjected to the Polymerase Chain Reaction (PCR for the detection of the encoding genes for the L1, L2 and B components and the toxin production capacity were evaluated with an immunoassay. A total of 23 [36.5%] isolates were identified carrying simultaneously the three tested genes, from which, 20 [86.9%] showed toxigenic capacity. 26 [41.3%] isolates did not carry any of genes tested and the other 14 [22.2%] were positive for one or two of them. The results showed a high toxigenic capacity among the B. cereus isolates able to produce the HBL, indicating a potential risk for consumers.

  17. Toxin Plasmids of Clostridium perfringens

    Science.gov (United States)

    Li, Jihong; Adams, Vicki; Bannam, Trudi L.; Miyamoto, Kazuaki; Garcia, Jorge P.; Uzal, Francisco A.; Rood, Julian I.

    2013-01-01

    SUMMARY In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

  18. Clostridium perfringens type A–E toxin plasmids

    Science.gov (United States)

    Freedman, John C.; Theoret, James R.; Wisniewski, Jessica A.; Uzal, Francisco A.; Rood, Julian I.; McClane, Bruce A.

    2014-01-01

    Clostridium perfringens relies upon plasmid-encoded toxin genes to cause intestinal infections. These toxin genes are associated with insertion sequences that may facilitate their mobilization and transfer, giving rise to new toxin plasmids with common backbones. Most toxin plasmids carry a transfer of clostridial plasmids locus mediating conjugation, which likely explains the presence of similar toxin plasmids in otherwise unrelated C. perfringens strains. The association of many toxin genes with insertion sequences and conjugative plasmids provides virulence flexibility when causing intestinal infections. However, incompatibility issues apparently limit the number of toxin plasmids maintained by a single cell. PMID:25283728

  19. Pertussis toxin

    Energy Technology Data Exchange (ETDEWEB)

    Sekura, R.D.; Moss, J.; Vaughan, M.

    1985-01-01

    This book contains 13 selections. Some of the titles are: Genetic and Functional Studies of Pertussis Toxin Substrates; Effect of Pertussis Toxin on the Hormonal Responsiveness of Different Tissues; Extracellular Adenylate Cyclase of Bordetella pertussis; and GTP-Regulatory Proteins are Introcellular Messagers: A Model for Hormone Action.

  20. Polyamine toxins

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Jensen, Lars S; Vogensen, Stine B

    2005-01-01

    Polyamine toxins, isolated from spiders and wasps, have been used as pharmacological tools for the study of ionotropic receptors, but their use have so far been hampered by their lack of selectivity. In this mini-review, we describe how careful synthetic modification of native polyamine toxins have...

  1. Botulinum toxin.

    Science.gov (United States)

    The National Institutes of Health Consensus Development Conference on Clinical Use of Botulinum Toxin brought together neurologists, ophthalmologists, otolaryngologists, speech pathologists, and other health care professionals as well as the public to address: the mechanisms of action of botulinum toxin, the indications and contraindications for botulinum toxin treatment, the general principles of technique of injection and handling for its safe and effective use, and the short-term and long-term side effects and complications of therapy. Following 2 days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement. Among their findings, the panel recommended that (1) botulinum toxin therapy is safe and effective for treating strabismus, blepharospasm, hemifacial spasm, adductor spasmodic dysphonia, jaw-closing oromandibular dystonia, and cervical dystonia; (2) botulinum toxin is not curative in chronic neurological disorders; (3) the safety of botulinum toxin therapy during pregnancy, breast feeding, and chronic use during childhood is unknown; (4) the long-term effects of chronic treatment with botulinum toxin remain unknown; and (5) botulinum toxin should be administered by committed interdisciplinary teams of physicians and related health care professionals with appropriate instrumentation. The full text of the consensus panel's statement follows.

  2. Iterative exposure of clonal BRIN-BD11 cells to ninhydrin enables selection of robust toxin-resistant cells but with decreased gene expression of insulin secretory function.

    Science.gov (United States)

    Liu, Hui-Kang; McCluskey, Jane T; McClenghan, Neville H; Flatt, Peter R

    2008-04-01

    Prevention of pancreatic beta-cell destruction combined with preservation of insulin secretory function is an important goal for cell-based diabetes therapy. This study describes the generation and characteristics of toxin-resistant beta-cells. By using iterative exposures to ninhydrin, a new class of robust ninhydrin-tolerant insulin-secreting BRIN-BD11 ninhydrin-tolerant (BRINnt) cells was generated. Low- and high-passage BRINnt cells were used to evaluate beta-cell function and tolerance against toxins in comparison with native BRIN-BD11 cells. Differences in viability, gene expression, insulin secretory function, antioxidant enzyme activity, DNA damage, and DNA repair efficiency were compared. BRIN-BD11 ninhydrin-tolerant cells exhibited resistance toward ninhydrin and hydrogen peroxide but not streptozotocin (STZ). Both total superoxide dismutase (SOD) and catalase enzyme activities of BRINnt cells were significantly enhanced, and ninhydrin-induced DNA damage was decreased. BRIN-BD11 ninhydrin-tolerant cells also exhibited enhanced DNA repair efficiency. However, this was accompanied by loss of secretagogue-induced insulin release, decreased cellular insulin content, and deficits in insulin and glucose transporter 2 gene expression. Prolonged culture of BRINnt cells in the absence of ninhydrin reversed the degenerated function of BRINnt cells but restored ninhydrin susceptibility. These data illustrate dissociation between beta-cell toxin resistance and secretory function, indicating difficulties in generation of robust and well-functioning cells using this approach.

  3. Occurrence, genotyping, shiga toxin genes and associated risk factors of E. coli isolated from dairy farms, handlers and milk consumers.

    Science.gov (United States)

    Awadallah, M A; Ahmed, H A; Merwad, A M; Selim, M A

    2016-11-01

    The objectives of the current study were to determine the occurrence and genotypes of E. coli in dairy farms, workers and milk consumers and to evaluate risk factors associated with contamination of milk in dairy farms. Molecular characterization of shiga toxin associated genes and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) finger printing of E. coli from different sources were also studied. Paired milk samples and rectal swabs from 125 dairy cows, rectal swabs from 82 calves and hand swabs from 45 dairy workers from five dairy farms were collected. In addition, 100 stool samples from 70 diarrheic and 30 healthy humans were collected and examined for the presence of E. coli. E. coli was isolated from milk (22.4%), dairy cattle feces (33.6%), calf feces (35.4%), dairy worker hand swabs (11.1%) and stools of milk consumers (2%, from diarrheic patients only). Only stx1 was identified in seven of 12 E. coli O125 isolated from different sources. High genetic diversity was determined (Simpson's index of diversity, D = 1) and E. coli O125 isolates were classified into 12 distinct profiles, E1-E12. The dendrogram analysis showed that two main clusters were generated. Mastitis in dairy cows was considered a risk factor associated with contamination of the produced milk with E. coli. The isolation of E. coli from rectal swabs of dairy cows and calves poses a zoonotic risk through consumption of unpasteurized contaminated dairy milk. Educational awareness should be developed to address risks related to consumption of raw milk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. TCR Gene Transfer: MAGE-C2/HLA-A2 and MAGE-A3/HLA-DP4 Epitopes as Melanoma-Specific Immune Targets

    Directory of Open Access Journals (Sweden)

    Trudy Straetemans

    2012-01-01

    Full Text Available Adoptive therapy with TCR gene-engineered T cells provides an attractive and feasible treatment option for cancer patients. Further development of TCR gene therapy requires the implementation of T-cell target epitopes that prevent “on-target” reactivity towards healthy tissues and at the same time direct a clinically effective response towards tumor tissues. Candidate epitopes that meet these criteria are MAGE-C2336-344/HLA-A2 (MC2/A2 and MAGE-A3243-258/HLA-DP4 (MA3/DP4. We molecularly characterized TCRαβ genes of an MC2/A2-specific CD8 and MA3/DP4-specific CD4 T-cell clone derived from melanoma patients who responded clinically to MAGE vaccination. We identified MC2/A2 and MA3/DP4-specific TCR-Vα3/Vβ28 and TCR-Vα38/Vβ2 chains and validated these TCRs in vitro upon gene transfer into primary human T cells. The MC2 and MA3 TCR were surface-expressed and mediated CD8 T-cell functions towards melanoma cell lines and CD4 T-cell functions towards dendritic cells, respectively. We intend to start testing these MAGE-specific TCRs in phase I clinical trial.

  5. Specific knockdown of delta-sarcoglycan gene in C2C12 in vitro causes post-translational loss of other sarcoglycans without mechanical stress.

    Science.gov (United States)

    Honda, Michiyo; Hosoda, Mari; Kanzawa, Nobuyuki; Tsuchiya, Takahide; Toyo-oka, Teruhiko

    2009-03-01

    The precise role of delta-sarcoglycan (SG) that is constitutively expressed in skeletal muscle cells and may serve for maintaining the sarcolemmal integrity has not been identified. The delta-SG protein is at first among SG complex. To specifically identify the role in C(2)C(12) cells during the myogenesis, we screened several RNA interference (RNAi) candidates at first, and knocked down both levels of the mRNA and protein, employing adenovirus-mediated RNAi. We found no morphological alteration at both myoblast and myotube stages by suppression of delta-SG. The specific knockdown of delta-SG accompanied a concomitant decrease of alpha-, beta-, and gamma-SGs preserving normal levels of each transcript. As for the localization, alpha-, beta-, and gamma-SGs were weakly stained on the cell membrane in delta-SG knockdown cells, whereas each SG in control cell was localized both on the cell membrane and myoplasm abundantly. This enhanced post-translational loss would represent similitude of the progression of cardiomuscular diseases in vitro. Different from cardiac muscle cells, skeletal muscle cell culture without muscle contraction may imply that mechanical stress per se is not primarily involved in the progression of limb-girdle muscular dystrophy. Furthermore, we have observed translocation of calpain-2 to cell membrane in delta-SG knockdown cells, suggesting that Ca(2+)-sensitive proteases, calpains closely take part in post-translational proteolysis.

  6. S-propranolol protected H9C2 cells from ischemia/reperfusion-induced apoptosis via downregultion of RACK1 Gene.

    Science.gov (United States)

    Jia, Xiongfei; Zhang, Li; Mao, Xiaoqin

    2015-01-01

    Ischemia-reperfusion (I/R) injury can lead to apoptotic death of heart cells and subsequently heart failure. Propranolol is widely used in the management of cardiovascular disorders, but the mechanism is still unclear. Our previous studies showed that activated protein kinase C1 (RACK1) was significantly down-regulated in human umbilical vein endothelial cells by S-propranolol. RACK1 may be a target protein of S-propranolol during I/R. At present, we constructed a lentiviral expression vector for RNA interference (RNAi) of RACK1. The interference efficiency of the lentivirus was confirmed by RT-PCR and western blot. H9C2 cells infected with Lv-RACK1-shRNA or control were subjected to simulate I/R in the presence and absence of S-propranolol. The release of cytokines and chemokines was determined by ELISA assay. Flow cytometry was employed to determine mitochondrial membrane potential (MMP), Ca(2+) concentration, reactive oxygen species (ROS) production, and cell apoptosis. We found that RACK1 RNAi and S-propranolol treatment remarkably protected I/R injured cells from apoptosis via attenuating the release of cytokines and chemokines, Ca(2+) overload, ROS concentration, and MMP. Furthermore, RACK1 RNAi and S-propranolol, separately and in combination, significantly reduced caspase-3 activity, cytochrome c release and JNK activation. RACK 1 can be considered as a target for drug development.

  7. Presence of Putative Repeat-in-Toxin Gene tosA in Escherichia coli Predicts Successful Colonization of the Urinary Tract

    Science.gov (United States)

    Vigil, Patrick D.; Stapleton, Ann E.; Johnson, James R.; Hooton, Thomas M.; Hodges, Andrew P.; He, Yongqun; Mobley, Harry L. T.

    2011-01-01

    ABSTRACT Uropathogenic Escherichia coli (UPEC) strains, which cause the majority of uncomplicated urinary tract infections (UTIs), carry a unique assortment of virulence or fitness genes. However, no single defining set of virulence or fitness genes has been found in all strains of UPEC, making the differentiation between UPEC and fecal commensal strains of E. coli difficult without the use of animal models of infection or phylogenetic grouping. In the present study, we consider three broad categories of virulence factors simultaneously to better define a combination of virulence factors that predicts success in the urinary tract. A total of 314 strains of E. coli, representing isolates from fecal samples, asymptomatic bacteriuria, complicated UTIs, and uncomplicated bladder and kidney infections, were assessed by multiplex PCR for the presence of 15 virulence or fitness genes encoding adhesins, toxins, and iron acquisition systems. The results confirm previous reports of gene prevalence among isolates from different clinical settings and identify several new patterns of gene associations. One gene, tosA, a putative repeat-in-toxin (RTX) homolog, is present in 11% of fecal strains but 25% of urinary isolates. Whereas tosA-positive strains carry an unusually high number (11.2) of the 15 virulence or fitness genes, tosA-negative strains have an average of only 5.4 virulence or fitness genes. The presence of tosA was predictive of successful colonization of a murine model of infection, even among fecal isolates, and can be used as a marker of pathogenic strains of UPEC within a distinct subset of the B2 lineage. PMID:21540363

  8. Recovery of plasmid pEMB1, whose toxin-antitoxin system stabilizes an ampicillin resistance-conferring β-lactamase gene in Escherichia coli, from natural environments.

    Science.gov (United States)

    Lee, Hyo Jung; Jin, Hyun Mi; Park, Moon Su; Park, Woojun; Madsen, Eugene L; Jeon, Che Ok

    2015-01-01

    Non-culture-based procedures were used to investigate plasmids showing ampicillin resistance properties in two different environments: remote mountain soil (Mt. Jeombong) and sludge (Tancheon wastewater treatment plant). Total DNA extracted from the environmental samples was directly transformed into Escherichia coli TOP10, and a single and three different plasmids were obtained from the mountain soil and sludge samples, respectively. Interestingly, the restriction fragment length polymorphism pattern of the plasmid from the mountain soil sample, designated pEMB1, was identical to the pattern of one of the three plasmids from the sludge sample. Complete DNA sequencing of plasmid pEMB1 (8,744 bp) showed the presence of six open reading frames, including a β-lactamase gene. Using BLASTX, the orf5 and orf6 genes were suggested to encode a CopG family transcriptional regulator and a plasmid stabilization system, respectively. Functional characterization of these genes using a knockout orf5 plasmid (pEMB1ΔparD) and the cloning and expression of orf6 (pET21bparE) indicated that these genes were antitoxin (parD) and toxin (parE) genes. Plasmid stability tests using pEMB1 and pEMB1ΔparDE in E. coli revealed that the orf5 and orf6 genes enhanced plasmid maintenance in the absence of ampicillin. Using a PCR-based survey, pEMB1-like plasmids were additionally detected in samples from other human-impacted sites (sludge samples) and two other remote mountain soil samples, suggesting that plasmids harboring a β-lactamase gene with a ParD-ParE toxin-antitoxin system occurs broadly in the environment. This study extends knowledge about the dissemination and persistence of antibiotic resistance genes in naturally occurring microbial populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  9. PCR detection of seven virulence and toxin genes of Campylobacter jejuni and Campylobacter coli isolates from Danish pigs and cattle and cytolethal distending toxin production of the isolates

    DEFF Research Database (Denmark)

    Bang, Dang Duong; Nielsen, E.M.; Scheutz, F.

    2003-01-01

    among 40 C. jejuni and C. coli isolates was detected by polymerase chain reaction. The CDT production of the isolates was determined on Vero, colon 205 and chicken embryo cells. The cadF, flaA, ceuE and cdtB genes were detected from 100% of the isolates. The cdtA and cdtC genes were found in 95.0 and 90.......0% of the isolates, respectively. The cdt gene cluster was detected in 82.5% isolates. Only 7.5% of the isolates were positive for virB11. Ninety-five per cent of the isolates produced CDT in Vero and colon 205 cell assays, and 90% of the isolates produced CDT in chicken embryo cell assays. Conclusions: High...

  10. Gene and antigen markers of Shiga-toxin producing E. coli from Michigan and Indiana river water: Occurrence and relation to recreational water quality criteria

    Science.gov (United States)

    Duris, J.W.; Haack, S.K.; Fogarty, L.R.

    2009-01-01

    The relation of bacterial pathogen occurrence to fecal indicator bacteria (FIB) concentrations used for recreational water quality criteria (RWQC) is poorly understood. This study determined the occurrence of Shiga-toxin producing Escherichia coli (STEC) markers and their relation to FIB concentrations in Michigan and Indiana river water. Using 67 fecal coliform (FC) bacteria cultures from 41 river sites in multiple watersheds, we evaluated the occurrence of five STEC markers: the Escherichia coli (EC) O157 antigen and gene, and the STEC virulence genes eaeA, stx1, and stx2. Simple isolations from selected FC cultures yielded viable EC O157. By both antigen and gene assays, EC O157 was detected in a greater proportion of samples exceeding rather than meeting FC RWQC (P decision-making. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  11. Counter regulation of ECRG4 gene expression by hypermethylation-dependent inhibition and the Sp1 transcription factor-dependent stimulation of the c2orf40 promoter.

    Science.gov (United States)

    Dang, Xitong; Zeng, Xiaorong; Coimbra, Raul; Eliceiri, Brian P; Baird, Andrew

    2017-12-15

    The human cytokine precursor ECRG4 has been associated with multiple physiological, developmental and pathophysiological processes involving cell proliferation, cell migration, innate immunity, inflammation, cancer progression and metastases. Although down-regulation of ECRG4 gene expression has been largely attributed to hypermethylation of CpG islands in the 5'untranslated region of the ECRG4 promoter, the mechanisms that underlie the dynamics of its regulation have never been systematically described. Here we show that the ECRG4 gene is widely expressed in human tissues and report that its core promoter lies between the -780 to +420 base pairs relative to the ATG start codon of the ECRG4 open reading frame. This sequence, which contains several CpG islands, also includes multiple overlapping Sp1 consensus binding sequences and a putative binding site for NF-kB activation. 5'RACE of mRNA derived from human leukocytes shows that ECRG4 transcription initiates from the guanidine at -11 from the initiation ATG of the ECRG4 open reading frame. While there is no canonical TATA- or CAAT-boxes proximal to this translational initiation site, there is a distal TATA-sequence in the 5'UTR. This region was identified as the sequence targeted by hypermethylation because in vitro methylation of plasmids encoding the ECRG4 promoter abolish promoter activity and the treatment of Jurkat cells (which naturally express ECRG4) with the methylation inhibitor 5-AzaC, increases endogenous ECRG4 expression. Because ChIP assays show that Sp1 binds the ECRG4 promoter, that forced Sp1 expression trans-activates the ECRG4 promoter and Sp1 inhibition with mithramycin inhibits ECRG4 expression, we conclude that the dynamic positive and negative regulatory elements controlling ECRG4 expression include a counter regulation between promoter methylation and Sp1 activation. Copyright © 2017. Published by Elsevier B.V.

  12. Carbon nanoparticles in lateral flow methods to detect genes encoding virulence factors of Shiga toxin-producing Escherichia coli

    NARCIS (Netherlands)

    Noguera, P.; Posthuma-Trumpie, G.A.; Tuil, van M.; Wal, van der F.J.; Boer, de A.; Moers, A.P.H.A.; Amerongen, van A.

    2011-01-01

    The use of carbon nanoparticles is shown for the detection and identification of different Shiga toxin-producing Escherichia coli virulence factors (vt1, vt2, eae and ehxA) and a 16S control (specific for E. coli) based on the use of lateral flow strips (nucleic acid lateral flow immunoassay,

  13. Venom gland transcriptomes of two elapid snakes (Bungarus multicinctus and Naja atra) and evolution of toxin genes

    National Research Council Canada - National Science Library

    Jiang, Yu; Li, Yan; Lee, Wenhui; Xu, Xun; Zhang, Yue; Zhao, Ruoping; Zhang, Yun; Wang, Wen

    2011-01-01

    ...) libraries for Bungarus multicinctus and Naja atra, respectively. We sequenced about 1500 cDNA clones for each of the venom cDNA libraries and screened BAC libraries of the two snakes by blot analysis using four kinds of toxin probes; i.e...

  14. Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich.

    Science.gov (United States)

    Ostermaier, Veronika; Schanz, Ferdinand; Köster, Oliver; Kurmayer, Rainer

    2012-12-07

    Harmful algal blooms deteriorate the services of aquatic ecosystems. They are often formed by cyanobacteria composed of genotypes able to produce a certain toxin, for example, the hepatotoxin microcystin (MC), but also of nontoxic genotypes that either carry mutations in the genes encoding toxin synthesis or that lost those genes during evolution. In general, cyanobacterial blooms are favored by eutrophication. Very little is known about the stability of the toxic/nontoxic genotype composition during trophic change. Archived samples of preserved phytoplankton on filters from aquatic ecosystems that underwent changes in the trophic state provide a so far unrealized possibility to analyze the response of toxic/nontoxic genotype composition to the environment. During a period of 29 years of re-oligotrophication of the deep, physically stratified Lake Zürich (1980 to 2008), the population of the stratifying cyanobacterium Planktothrix was at a minimum during the most eutrophic years (1980 to 1984), but increased and dominated the phytoplankton during the past two decades. Quantitative polymerase chain reaction revealed that during the whole observation period the proportion of the toxic genotype was strikingly stable, that is, close to 100%. Inactive MC genotypes carrying mutations within the MC synthesis genes never became abundant. Unexpectedly, a nontoxic genotype, which lost its MC genes during evolution, and which could be shown to be dominant under eutrophic conditions in shallow polymictic lakes, also co-occurred in Lake Zürich but was never abundant. As it is most likely that this nontoxic genotype contains relatively weak gas vesicles unable to withstand the high water pressure in deep lakes, it is concluded that regular deep mixing selectively reduced its abundance through the destruction of gas vesicles. The stability in toxic genotype dominance gives evidence for the adaptation to deep mixing of a genotype that retained the MC gene cluster during

  15. Identification of the cellular receptor of Clostridium spiroforme toxin.

    Science.gov (United States)

    Papatheodorou, Panagiotis; Wilczek, Claudia; Nölke, Thilo; Guttenberg, Gregor; Hornuss, Daniel; Schwan, Carsten; Aktories, Klaus

    2012-04-01

    Clostridium spiroforme produces the binary actin-ADP-ribosylating toxin CST (C. spiroforme toxin), which has been proposed to be responsible for diarrhea, enterocolitis, and eventually death, especially in rabbits. Here we report on the recombinant production of the enzyme component (CSTa) and the binding component (CSTb) of C. spiroforme toxin in Bacillus megaterium. By using the recombinant toxin components, we show that CST enters target cells via the lipolysis-stimulated lipoprotein receptor (LSR), which has been recently identified as the host cell receptor of the binary toxins Clostridium difficile transferase (CDT) and Clostridium perfringens iota toxin. Microscopic studies revealed that CST, but not the related Clostridium botulinum C2 toxin, colocalized with LSR during toxin uptake and traffic to endosomal compartments. Our findings indicate that CST shares LSR with C. difficile CDT and C. perfringens iota toxin as a host cell surface receptor.

  16. Evaluation of a cytolethal distending toxin (cdt) gene-based species-specific multiplex PCR assay for the identification of Campylobacter strains isolated from diarrheal patients in Japan.

    Science.gov (United States)

    Kabir, S M Lutful; Kikuchi, Ken; Asakura, Masahiro; Shiramaru, Sachi; Tsuruoka, Naoki; Goto, Aeko; Hinenoya, Atsushi; Yamasaki, Shinji

    2011-01-01

    We have developed a cytolethal distending toxin (cdt) gene-based species-specific multiplex PCR assay for the detection and identification of Campylobacter jejuni, C. coli, and C. fetus. The applicability of this assay was evaluated with 325 Campylobacter strains isolated from diarrheal patients in Japan and the results were compared with those obtained by other genetic methods, including hipO gene detection and 16S rRNA gene sequencing. Of the 325 strains analyzed, 314 and 11 were identified as C. jejuni and C. coli, respectively, by combination of hipO gene detection and 16S rRNA gene sequencing. When the multiplex PCR assay was employed, 309, 310, and 314 strains were identified as C. jejuni on the basis of cdtA, cdtB, and cdtC gene-specific primers, respectively. Similarly, 11, 11, and 10 strains were identified as C. coli on the basis of cdtA, cdtB, and cdtC gene-specific primers, respectively. Sequence analysis of the cdt gene region of 6 strains (5 C. jejuni and 1 C. coli) which did not yield specific PCR products in any of the cdt gene-based multiplex PCR assays revealed deletions or mutations of the cdt genes. Pulsed-field gel electrophoresis indicated that C. jejuni and C. coli strains were genetically diverse. Taken together, these findings suggest that the cdtC gene-based multiplex PCR seems to be a particularly simple and rapid method for differentiating between species of Campylobacter strains, such as C. jejuni and C. coli. However, combination of these multiplex PCR assays will allow more accurate identification.

  17. Binding of superantigen toxins into the CD28 homodimer interface is essential for induction of cytokine genes that mediate lethal shock.

    Directory of Open Access Journals (Sweden)

    Gila Arad

    2011-09-01

    Full Text Available Bacterial superantigens, a diverse family of toxins, induce an inflammatory cytokine storm that can lead to lethal shock. CD28 is a homodimer expressed on T cells that functions as the principal costimulatory ligand in the immune response through an interaction with its B7 coligands, yet we show here that to elicit inflammatory cytokine gene expression and toxicity, superantigens must bind directly into the dimer interface of CD28. Preventing access of the superantigen to CD28 suffices to block its lethality. Mice were protected from lethal superantigen challenge by short peptide mimetics of the CD28 dimer interface and by peptides selected to compete with the superantigen for its binding site in CD28. Superantigens use a conserved β-strand/hinge/α-helix domain of hitherto unknown function to engage CD28. Mutation of this superantigen domain abolished inflammatory cytokine gene induction and lethality. Structural analysis showed that when a superantigen binds to the T cell receptor on the T cell and major histocompatibility class II molecule on the antigen-presenting cell, CD28 can be accommodated readily as third superantigen receptor in the quaternary complex, with the CD28 dimer interface oriented towards the β-strand/hinge/α-helix domain in the superantigen. Our findings identify the CD28 homodimer interface as a critical receptor target for superantigens. The novel role of CD28 as receptor for a class of microbial pathogens, the superantigen toxins, broadens the scope of pathogen recognition mechanisms.

  18. Hydra actinoporin-like toxin-1, an unusual hemolysin from the nematocyst venom of Hydra magnipapillata which belongs to an extended gene family.

    Science.gov (United States)

    Glasser, Eliezra; Rachamim, Tamar; Aharonovich, Dikla; Sher, Daniel

    2014-12-01

    Cnidarians rely on their nematocysts and the venom injected through these unique weaponry systems to catch prey and protect themselves from predators. The development and physiology of the nematocysts of Hydra magnipapillata, a classic model organism, have been intensively studied, yet the composition and biochemical activity of their venom components are mostly unknown. Here, we show that hydra actinoporin-like toxins (HALTs), which have previously been associated with Hydra nematocysts, belong to a multigene family comprising six genes, which have diverged from a single common ancestor. All six genes are expressed in a population of Hydra magnipapillata. When expressed recombinantly, HALT-1 (Δ-HYTX-Hma1a), an actinoporin-like protein found in the stenoteles (the main penetrating nematocysts used in prey capture), reveals hemolytic activity, albeit about two-thirds lower than that of the anemone actinoporin equinatoxin II (EqTII, Δ-AITX-Aeq1a). HALT-1 also differs from EqTII in the size of its pores, and likely does not utilize sphingomyelin as a membrane receptor. We describe features of the HALT-1 sequence which may contribute to this difference in activity, and speculate on the role of this unusual family of pore-forming toxins in the ecology of Hydra. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Screening for the presence of mcr-1/mcr-2 genes in Shiga toxin-producing Escherichia coli recovered from a major produce-production region in California

    Science.gov (United States)

    Mavrici, Daniela; Yambao, Jaszemyn C.; Lee, Bertram G.; Quiñones, Beatriz; He, Xiaohua

    2017-01-01

    The rapid spreading of polymyxin E (colistin) resistance among bacterial strains through the horizontally transmissible mcr-1 and mcr-2 plasmids has become a serious concern. The emergence of these genes in Shiga toxin-producing Escherichia coli (STEC), a group of human pathogenic bacteria was even more worrisome, urging us to investigate the prevalence of mcr genes among STEC isolates. A total of 1000 STEC isolates, recovered from livestock, wildlife, produce and other environmental sources in a major production region for leafy vegetables in California during 2006–2014, were screened by PCR for the presence of plasmid-borne mcr-1 and mcr-2. All isolates tested yielded negative results, indicating if any, the occurrence rate of mcr-1/mcr-2 among STEC was very low in this agricultural region. This study provides valuable information such as sample size needed and methodologies for future surveillance programs of antimicrobial resistance. PMID:29117270

  20. Response of last instar Helicoverpa armígera larvae to Bt toxin ingestion: changes in the development and in the CYP6AE14, CYP6B2 and CYP9A12 gene expression.

    Science.gov (United States)

    Muñoz, Pilar; López, Carmen; Moralejo, Marian; Pérez-Hedo, Meritxell; Eizaguirre, Matilde

    2014-01-01

    Bt crops are able to produce Cry proteins, which were originally present in Bacillus thuringiensis bacteria. Although Bt maize is very efficient against corn borers, Spanish crops are also attacked by the earworm H. armigera, which is less susceptible to Bt maize. Many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome P450 monooxygenases. This paper examines the response of last instar H. armigera larvae to feeding on a diet with Bt and non-Bt maize leaves in larval development and in the gene expression of three P450 cytochromes: CYP6AE14, CYP6B2 and CYP9A12. Larvae fed on sublethal amounts of the Bt toxin showed reduced food ingestion and reduced growth and weight, preventing most of them from achieving the critical weight and pupating; additionally, after feeding for one day on the Bt diet the larvae showed a slight increase in juvenile hormone II in the hemolymp. Larvae fed on the non-Bt diet showed the highest CYP6AE14, CYP6B2 and CYP9A12 expression one day after feeding on the non-Bt diet, and just two days later the expression decreased abruptly, a finding probably related to the developmental programme of the last instar. Moreover, although the response of P450 genes to plant allelochemicals and xenobiotics has been related in general to overexpression in the resistant insect, or induction of the genes when feeding takes place, the expression of the three genes studied was suppressed in the larvae feeding on the Bt toxin. The unexpected inhibitory effect of the Cry1Ab toxin in the P450 genes of H. armigera larvae should be thoroughly studied to determine whether this response is somehow related to the low susceptibility of the species to the Bt toxin.

  1. Response of last instar Helicoverpa armigera larvae to Bt toxin ingestion: changes in the development and in the CYP6AE14, CYP6B2 and CYP9A12 gene expression.

    Directory of Open Access Journals (Sweden)

    Pilar Muñoz

    Full Text Available Bt crops are able to produce Cry proteins, which were originally present in Bacillus thuringiensis bacteria. Although Bt maize is very efficient against corn borers, Spanish crops are also attacked by the earworm H. armigera, which is less susceptible to Bt maize. Many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome P450 monooxygenases. This paper examines the response of last instar H. armigera larvae to feeding on a diet with Bt and non-Bt maize leaves in larval development and in the gene expression of three P450 cytochromes: CYP6AE14, CYP6B2 and CYP9A12. Larvae fed on sublethal amounts of the Bt toxin showed reduced food ingestion and reduced growth and weight, preventing most of them from achieving the critical weight and pupating; additionally, after feeding for one day on the Bt diet the larvae showed a slight increase in juvenile hormone II in the hemolymp. Larvae fed on the non-Bt diet showed the highest CYP6AE14, CYP6B2 and CYP9A12 expression one day after feeding on the non-Bt diet, and just two days later the expression decreased abruptly, a finding probably related to the developmental programme of the last instar. Moreover, although the response of P450 genes to plant allelochemicals and xenobiotics has been related in general to overexpression in the resistant insect, or induction of the genes when feeding takes place, the expression of the three genes studied was suppressed in the larvae feeding on the Bt toxin. The unexpected inhibitory effect of the Cry1Ab toxin in the P450 genes of H. armigera larvae should be thoroughly studied to determine whether this response is somehow related to the low susceptibility of the species to the Bt toxin.

  2. Transcriptional profiling of type II toxin-antitoxin genes of Helicobacter pylori under different environmental conditions: identification of HP0967-HP0968 system

    Directory of Open Access Journals (Sweden)

    MIGUEL A DE LA CRUZ

    2016-11-01

    Full Text Available Helicobacter pylori is a Gram-negative bacterium that colonizes the human gastric mucosa and is responsible for causing peptic ulcers and gastric carcinoma. The expression of virulence factors allows the persistence of H. pylori in the stomach, which results in a chronic, sometimes uncontrolled inflammatory response. Type II toxin-antitoxin systems have emerged as important virulence factors in many pathogenic bacteria. Three type II toxin-antitoxin (TA systems have previously been identified in the genome of H. pylori 26695: HP0315-HP0316, HP0892-HP0893, and HP0894-HP0895. Here we characterized a heretofore undescribed type II TA system in H. pylori, HP0967-HP0968, which is encoded by the bicistronic operon hp0968-hp0967 and belongs to the Vap family. The predicted HP0967 protein is a toxin with ribonuclease activity whereas HP0968 is an antitoxin that binds to its own regulatory region. We found that all type II TA systems were expressed in H. pylori during early stationary growth phase, and differentially expressed in the presence of urea, nickel, and iron, although the hp0968-hp0967 pair was the most affected under these environmental conditions. Transcription of hp0968-hp0967 was strongly induced in a mature H. pylori biofilm and when the bacteria interacted with AGS epithelial cells. Kanamycin and chloramphenicol considerably boosted transcription levels of all the four type II TA systems. The hp0968-hp0967 TA system was the most frequent among 317 H. pylori strains isolated from all over the world. This study is the first report on the transcription of type II TA genes in H. pylori under different environmental conditions. Our data show that the HP0967 and HP0968 proteins constitute a bona fide type II TA system in H. pylori, whose expression is regulated by environmental cues, which are relevant in the context of infection of the human gastric mucosa.

  3. Molecular investigation of tRNA genes integrity and its relation to pathogenicity islands in Shiga toxin-producing Escherichia coli (STEC strains

    Directory of Open Access Journals (Sweden)

    Rogério Carlos Novais

    2004-01-01

    Full Text Available tRNA genes are known target sites for the integration of pathogenicity islands (PAI and other genetic elements, such as bacteriophages, into bacterial genome. In most STEC (Shiga toxin-producing Escherichia coli, the PAI called LEE (locus of enterocyte effacement is related to bacterial virulence and is mostly associated to the tRNA genes selC and pheU. In this work, we first investigated the relationship of LEE with tRNA genes selC and pheU in 43 STEC strains. We found that 28 strains (65% had a disrupted selC and/or pheU. Three of these strains (637/1, 650/5 and 654/3 were chosen to be submitted to a RAPD-PCR technique modified by the introduction of specific primers (corresponding to the 5'end of genes selC and pheU into the reaction, which we called "anchored RAPD-PCR". The PCR fragments obtained were transferred onto membranes, and those fragments which hybridized to selC and pheU probes were isolated. One of these fragments from strain 637/1 was partially sequenced. An 85-nucleotide sequence was found to be similar to the cfxA2 gene that encodes a beta-lactamase and is part of transposon Tn4555, a pathogenicity island originally integrated into the Bacteroides genome.

  4. Prevalence of enterotoxins and toxin gene profiles of Staphylococcus aureus isolates recovered from a bakery involved in a second staphylococcal food poisoning occurrence.

    Science.gov (United States)

    Hait, J; Tallent, S; Melka, D; Keys, C; Bennett, R

    2014-09-01

    The study objective was to characterize and analyse the distribution of enterotoxins and genes encoding enterotoxins in Staphylococcus aureus strains recovered from the 601 environment and ingredient samples obtained during multiple inspections of a bakery implicated in two separate staphylococcal food poisoning incidents. Staphylococcus aureus isolates were evaluated using serological assays for identification of classical staphylococcal enterotoxins (SEs) SEA-SEE and polymerase chain reaction for the detection of newly described SE and SE-like enterotoxin genes seg-seu. Pulsed field gel electrophoresis identified thirteen pattern types. During these investigations, a total of 585 environmental swabs and 16 raw ingredient samples were collected by investigators, 85 of which were confirmed to contain Staph. aureus; of those isolates, 95·3% (81/85) harboured enterotoxin genes and 4·7% (4/85) carried newly described SE and SE-like enterotoxin genes in the absence of classical enterotoxins. Our research demonstrates the prevalence and diversity of classical SEs and the probable underestimated impact of nonclassical SE and SE-like enterotoxins role in domestic staphylococcal food poisoning outbreaks. Given the abundance of SEs and SE-like toxins, these findings illustrate the utilization of PCR for enterotoxin gene identification and its significance in outbreak investigations. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  5. Quantity of the dinoflagellate sxtA4 gene and cell density correlates with paralytic shellfish toxin production in Alexandrium ostenfeldii blooms.

    Science.gov (United States)

    Savela, Henna; Harju, Kirsi; Spoof, Lisa; Lindehoff, Elin; Meriluoto, Jussi; Vehniäinen, Markus; Kremp, Anke

    2016-02-01

    Many marine dinoflagellates, including several species of the genus Alexandrium, Gymnodinium catenatum, and Pyrodinium bahamense are known for their capability to produce paralytic shellfish toxins (PST), which can cause severe, most often food-related poisoning. The recent discovery of the first PST biosynthesis genes has laid the foundation for the development of molecular detection methods for monitoring and study of PST-producing dinoflagellates. In this study, a probe-based qPCR method for the detection and quantification of the sxtA4 gene present in Alexandrium spp. and Gymnodinium catenatum was designed. The focus was on Alexandrium ostenfeldii, a species which recurrently forms dense toxic blooms in areas within the Baltic Sea. A consistent, positive correlation between the presence of sxtA4 and PST biosynthesis was observed, and the species was found to maintain PST production with an average of 6 genomic copies of sxtA4. In August 2014, A. ostenfeldii populations were studied for cell densities, PST production, as well as sxtA4 and species-specific LSU copy numbers in Föglö, Åland, Finland, where an exceptionally dense bloom, consisting of 6.3×106cellsL-1, was observed. Cell concentrations, and copy numbers of both of the target genes were positively correlated with total STX, GTX2, and GTX3 concentrations in the environment, the cell density predicting toxin concentrations with the best accuracy (Spearman's ρ=0.93, p<0.01). The results indicated that all A. ostenfeldii cells in the blooms harbored the genetic capability of PST production, making the detection of sxtA4 a good indicator of toxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. The prevalence and polymorphisms of zonula occluden toxin gene in multiple Campylobacter concisus strains isolated from saliva of patients with inflammatory bowel disease and controls.

    Directory of Open Access Journals (Sweden)

    Vikneswari Mahendran

    Full Text Available Campylobacterconcisus is an oral bacterium. A number of studies detected a significantly higher prevalence of C. concisus in the intestinal tract of patients with inflammatory bowel disease (IBD as compared to controls. The prevalence of zonula occluden toxin (zot gene, which encodes a toxin known to increase intestinal permeability, in oral C. concisus strains is unknown. Increased intestinal permeability is a feature of IBD. A total of 56 oral C. concisus strains isolated from 19 patients with IBD and 20 controls were examined (some individuals were colonized with multiple strains. A filtration method was used for isolation of C. concisus from saliva samples. SDS-PAGE was used to define strains. PCR was used to amplify zot from C. concisus strains. Positive PCR products were sequenced and the nucleotides and amino acids were compared. Of the 56 oral C. concisus strains examined, 17 strains (30.4% were positive for zot. The prevalence of zot-positive oral C. concisus strains was 54.5% in patients with active IBD, which was not significantly different from that in healthy controls (40%. Polymorphisms of C. concisus zot were revealed. zot (808T , zot (350-351AC and zot (Multiple were detected only in patients with IBD, but not in healthy controls. Both zot (808T and zot (Multiple alleles resulted in substitution of valine at position 270, which occurred in 36.4% of patients with active IBD but not in healthy controls (P = 0.011. Furthermore, the prevalence of multiple oral C. concisus strains in patients with active IBD was significantly higher than that in healthy controls (P = 0.013. This is the first study reporting the prevalence of zot in human oral C. concisus strains and the polymorphisms of C. concisus zot gene. The data suggest that the possible role of C. concisus strains containing specific polymorphic forms of zot gene in human IBD should be investigated.

  7. The ancient mammalian KRAB zinc finger gene cluster on human chromosome 8q24.3 illustrates principles of C2H2 zinc finger evolution associated with unique expression profiles in human tissues

    Directory of Open Access Journals (Sweden)

    Ding Guohui

    2010-03-01

    Full Text Available Abstract Background Expansion of multi-C2H2 domain zinc finger (ZNF genes, including the Krüppel-associated box (KRAB subfamily, paralleled the evolution of tetrapodes, particularly in mammalian lineages. Advances in their cataloging and characterization suggest that the functions of the KRAB-ZNF gene family contributed to mammalian speciation. Results Here, we characterized the human 8q24.3 ZNF cluster on the genomic, the phylogenetic, the structural and the transcriptome level. Six (ZNF7, ZNF34, ZNF250, ZNF251, ZNF252, ZNF517 of the seven locus members contain exons encoding KRAB domains, one (ZNF16 does not. They form a paralog group in which the encoded KRAB and ZNF protein domains generally share more similarities with each other than with other members of the human ZNF superfamily. The closest relatives with respect to their DNA-binding domain were ZNF7 and ZNF251. The analysis of orthologs in therian mammalian species revealed strong conservation and purifying selection of the KRAB-A and zinc finger domains. These findings underscore structural/functional constraints during evolution. Gene losses in the murine lineage (ZNF16, ZNF34, ZNF252, ZNF517 and potential protein truncations in primates (ZNF252 illustrate ongoing speciation processes. Tissue expression profiling by quantitative real-time PCR showed similar but distinct patterns for all tested ZNF genes with the most prominent expression in fetal brain. Based on accompanying expression signatures in twenty-six other human tissues ZNF34 and ZNF250 revealed the closest expression profiles. Together, the 8q24.3 ZNF genes can be assigned to a cerebellum, a testis or a prostate/thyroid subgroup. These results are consistent with potential functions of the ZNF genes in morphogenesis and differentiation. Promoter regions of the seven 8q24.3 ZNF genes display common characteristics like missing TATA-box, CpG island-association and transcription factor binding site (TFBS modules. Common TFBS

  8. Unusual accelerated rate of deletions and insertions in toxin genes in the venom glands of the pygmy copperhead (Austrelaps labialis) from kangaroo island

    OpenAIRE

    Kini R Manjunatha; Reza Md Abu; Tram Nguyen; Doley Robin

    2008-01-01

    Abstract Background Toxin profiling helps in cataloguing the toxin present in the venom as well as in searching for novel toxins. The former helps in understanding potential pharmacological profile of the venom and evolution of toxins, while the latter contributes to understanding of novel mechanisms of toxicity and provide new research tools or prototypes of therapeutic agents. Results The pygmy copperhead (Austrelaps labialis) is one of the less studied species. In this present study, an at...

  9. Toxins-antitoxins: diversity, evolution and function.

    Science.gov (United States)

    Hayes, Finbarr; Van Melderen, Laurence

    2011-10-01

    Genes for toxin-antitoxin (TA) complexes are widespread in prokaryote genomes, and species frequently possess tens of plasmid and chromosomal TA loci. The complexes are categorized into three types based on genetic organization and mode of action. The toxins universally are proteins directed against specific intracellular targets, whereas the antitoxins are either proteins or small RNAs that neutralize the toxin or inhibit toxin synthesis. Within the three types of complex, there has been extensive evolutionary shuffling of toxin and antitoxin genes leading to considerable diversity in TA combinations. The intracellular targets of the protein toxins similarly are varied. Numerous toxins, many of which are sequence-specific endoribonucleases, dampen protein synthesis levels in response to a range of stress and nutritional stimuli. Key resources are conserved as a result ensuring the survival of individual cells and therefore the bacterial population. The toxin effects generally are transient and reversible permitting a set of dynamic, tunable responses that reflect environmental conditions. Moreover, by harboring multiple toxins that intercede in protein synthesis in response to different physiological cues, bacteria potentially sense an assortment of metabolic perturbations that are channeled through different TA complexes. Other toxins interfere with the action of topoisomersases, cell wall assembly, or cytoskeletal structures. TAs also play important roles in bacterial persistence, biofilm formation and multidrug tolerance, and have considerable potential both as new components of the genetic toolbox and as targets for novel antibacterial drugs.

  10. [Phalloidian toxins].

    Science.gov (United States)

    Larcan, A; Lamarche, M; Lambert, H

    1979-01-01

    The phalloidian toxins are very complex. The classification proposed by Wieland distinguishes between the various amatoxins and phallotoxins. The authors study successively: Methods of isolation, the general structure and chemical composition, their localization and concentration in mushrooms. This is an analytical study of the phallotoxins and amadoxins. Various experimental intoxication protocols using total extracts of the toxins purified with different doses and different animals have revealed the main signs of experimental intoxication with phallotoxins. This is characterized especially by hepatic and renal lesions. The phallotoxins have a more specific action on the cell membrane and metabolism. The amatoxins have a more specific action on the cell nucleus and protein synthesis. The action on DNA dependent RNA polymerases is particularly characteristic.

  11. Botulinum Toxin

    Science.gov (United States)

    2009-01-01

    intercostal muscle (Hilmas, unpublished data). All serotypes showed a similar ability to produce complete muscular paralysis in ex vivo human intercostal...routes of exposure include, in order of descending frequency: dysphagia, xerostomia, diplopia, dysarthria, fatigue , ptosis of the eyelids...Medical and Public Health Manage- ment. JAMA 285: 1059-70. Bakry, N., Kamata, Y., Simpson, L. (1997). Expression of botu- linum toxin binding sites in

  12. A Cytolethal Distending Toxin Gene-Based Multiplex PCR Assay for Campylobacter jejuni, C. fetus, C. coli, C. upsaliensis, C. hyointestinalis, and C. lari.

    Science.gov (United States)

    Kamei, Kazumasa; Kawabata, Hiroki; Asakura, Masahiro; Samosornsuk, Worada; Hinenoya, Atsushi; Nakagawa, Shinsaku; Yamasaki, Shinji

    2016-05-20

    In this study, we devised a multiplex PCR assay based on the gene of cytolethal distending toxin (cdt) B subunit to simultaneously detect and discriminate Campylobacter jejuni, C. fetus, C. coli, C. upsaliensis, C. hyointestinalis, and C. lari. Species-specific PCR products were successfully obtained from all 38 C. jejuni, 12 C. fetus, 39 C. coli, 22 C. upsaliensis, 24 C. hyointestinalis, and 7 C. lari strains tested. On the other hand, no specific PCR products were obtained from other campylobacters and bacterial species tested (41 strains in total). The proposed multiplex PCR assay is a valuable tool for detection and descrimination of 6 major Campylobacter species, that are associated with gastrointestinal diseases in humans.

  13. Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich

    Directory of Open Access Journals (Sweden)

    Ostermaier Veronika

    2012-12-01

    Full Text Available Abstract Background Harmful algal blooms deteriorate the services of aquatic ecosystems. They are often formed by cyanobacteria composed of genotypes able to produce a certain toxin, for example, the hepatotoxin microcystin (MC, but also of nontoxic genotypes that either carry mutations in the genes encoding toxin synthesis or that lost those genes during evolution. In general, cyanobacterial blooms are favored by eutrophication. Very little is known about the stability of the toxic/nontoxic genotype composition during trophic change. Results Archived samples of preserved phytoplankton on filters from aquatic ecosystems that underwent changes in the trophic state provide a so far unrealized possibility to analyze the response of toxic/nontoxic genotype composition to the environment. During a period of 29 years of re-oligotrophication of the deep, physically stratified Lake Zürich (1980 to 2008, the population of the stratifying cyanobacterium Planktothrix was at a minimum during the most eutrophic years (1980 to 1984, but increased and dominated the phytoplankton during the past two decades. Quantitative polymerase chain reaction revealed that during the whole observation period the proportion of the toxic genotype was strikingly stable, that is, close to 100%. Inactive MC genotypes carrying mutations within the MC synthesis genes never became abundant. Unexpectedly, a nontoxic genotype, which lost its MC genes during evolution, and which could be shown to be dominant under eutrophic conditions in shallow polymictic lakes, also co-occurred in Lake Zürich but was never abundant. As it is most likely that this nontoxic genotype contains relatively weak gas vesicles unable to withstand the high water pressure in deep lakes, it is concluded that regular deep mixing selectively reduced its abundance through the destruction of gas vesicles. Conclusions The stability in toxic genotype dominance gives evidence for the adaptation to deep mixing of a

  14. Genomics study of the exposure effect of Gymnodinium catenatum, a paralyzing toxin producer, on Crassostrea gigas' defense system and detoxification genes.

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    Norma García-Lagunas

    Full Text Available BACKGROUND: Crassostrea gigas accumulates paralytic shellfish toxins (PST associated with red tide species as Gymnodinium catenatum. Previous studies demonstrated bivalves show variable feeding responses to toxic algae at physiological level; recently, only one study has reported biochemical changes in the transcript level of the genes involved in C. gigas stress response. PRINCIPAL FINDINGS: We found that 24 h feeding on toxic dinoflagellate cells (acute exposure induced a significant decrease in clearance rate and expression level changes of the genes involved in antioxidant defense (copper/zinc superoxide dismutase, Cu/Zn-SOD, cell detoxification (glutathione S-transferase, GST and cytochrome P450, CPY450, intermediate immune response activation (lipopolysaccharide and beta glucan binding protein, LGBP, and stress responses (glutamine synthetase, GS in Pacific oysters compared to the effects with the non-toxic microalga Isochrysis galbana. A sub-chronic exposure feeding on toxic dinoflagellate cells for seven and fourteen days (30×10³ cells mL⁻¹ showed higher gene expression levels. A significant increase was observed in Cu/Zn-SOD, GST, and LGBP at day 7 and a major increase in GS and CPY450 at day 14. We also observed that oysters fed only with G. catenatum (3×10³ cells mL⁻¹ produced a significant increase on the transcription level than in a mixed diet (3×10³ cells mL⁻¹ of G. catenatum+0.75×10⁶ cells mL⁻¹ I. galbana in all the analyzed genes. CONCLUSIONS: Our results provide gene expression data of PST producer dinoflagellate G. catenatum toxic effects on C. gigas, a commercially important bivalve. Over expressed genes indicate the activation of a potent protective mechanism, whose response depends on both cell concentration and exposure time against these toxic microalgae. Given the importance of dinoflagellate blooms in coastal environments, these results provide a more comprehensive overview of how oysters respond to

  15. Characterization of plasmids carrying the blaOXA-24/40 carbapenemase gene and the genes encoding the AbkA/AbkB proteins of a toxin/antitoxin system.

    Science.gov (United States)

    Mosqueda, Noraida; Gato, Eva; Roca, Ignasi; López, María; de Alegría, Carlos Ruíz; Fernández Cuenca, Felipe; Martínez-Martínez, Luis; Pachón, Jerónimo; Cisneros, José Miguel; Rodríguez-Baño, Jesús; Pascual, Alvaro; Vila, Jordi; Bou, Germán; Tomás, María

    2014-10-01

    Carbapenem-resistant Acinetobacter baumannii (CRAb) is a major source of nosocomial infections in Spain associated with the production of OXA-58-like or OXA-24/40-like β-lactamase enzymes. We analysed the plasmids carrying the bla(OXA-24/40)-like gene in CRAb isolates obtained a decade apart. The presence of β-lactamases was screened for by PCR (metallo-β-lactamases, carbapenem-hydrolysing class D β-lactamases, GES and KPC) in 101 CRAb isolates obtained in two multicentre studies (GEIH/REIPI-Ab-2000 and GEIH/REIPI-Ab-2010; n = 493 Acinetobacter spp). We analysed the distribution and characterization of the plasmids carrying the bla(OXA-24/40)-like gene and sequenced two plasmids, AbATCC223p (2000) and AbATCC329p (2010) from A. baumannii ATCC 17978 transformants. Acquisition of the bla(OXA-24/40)-like gene was the main mechanism underlying resistance to carbapenems (48.7% in 2000 compared with 51.6% in 2010). This gene was mainly isolated in ST2 A. baumannii strains in both studies, although some novel STs (ST79 and ST80) appeared in 2010. The gene was located in plasmids (8-12 kbp) associated with the repAci2 or repAci2/repGR12 types. The sequences of AbATCC223p (8840 bp) and AbATCC329p (8842 bp) plasmids were similar, particularly regarding the presence of the genes encoding the AbkA/AbkB proteins associated with the toxin/antitoxin system. Moreover, the abkA/abkB gene sequences (>96% identity) were also located in plasmids harbouring the bla(OXA-58)-like gene. The action of OXA-24/40 and OXA-58 β-lactamase-like enzymes represents the main mechanism underlying resistance to carbapenems in Spain in the last decade. AbkA/AbkB proteins in the toxin/antitoxin system may be involved in the successful dissemination of plasmids carrying the bla(OXA-24/40)-like gene, and probably also the bla(OXA-58)-like gene, thus contributing to the plasmid stability. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial

  16. Draft genome sequence of pathogenic bacteria Vibrio parahaemolyticus strain Ba94C2, associated with acute hepatopancreatic necrosis disease isolate from South America

    Directory of Open Access Journals (Sweden)

    Leda Restrepo

    2016-09-01

    Full Text Available Vibrio parahaemolyticus is a pathogenic bacteria which has been associated to the early mortality syndrome (EMS also known as hepatopancreatic necrosis disease (AHPND causing high mortality in shrimp farms. Pathogenic strains contain two homologous genes related to insecticidal toxin genes, PirA and PirB, these toxin genes are located on a plasmid contained within the bacteria. Genomic sequences have allowed the finding of two strains with a divergent structure related to the geographic region from where they were found. The isolates from the geographic collection of Southeast Asia and Mexico show variable regions on the plasmid genome, indicating that even though they are not alike they still conserve the toxin genes. In this paper, we report for the first time, a pathogenic V. parahaemolyticus strain in shrimp from South America that showed symptoms of AHPND. The genomic analysis revealed that this strain of V. parahaemolyticus found in South America appears to be more related to the Southeast Asia as compared to the Mexican strains. This finding is of major importance for the shrimp industry, especially in regards to the urgent need for disease control strategies to avoid large EMS outbreaks and economic loss, and to determine its dispersion in South America. The whole-genome shotgun project of V. parahaemolyticus strain Ba94C2 have been deposited at DDBJ/EMBL/GenBank under the accession PRJNA335761.

  17. Draft genome sequence of pathogenic bacteria Vibrio parahaemolyticus strain Ba94C2, associated with acute hepatopancreatic necrosis disease isolate from South America.

    Science.gov (United States)

    Restrepo, Leda; Bayot, Bonny; Betancourt, Irma; Pinzón, Andres

    2016-09-01

    Vibrio parahaemolyticus is a pathogenic bacteria which has been associated to the early mortality syndrome (EMS) also known as hepatopancreatic necrosis disease (AHPND) causing high mortality in shrimp farms. Pathogenic strains contain two homologous genes related to insecticidal toxin genes, PirA and PirB, these toxin genes are located on a plasmid contained within the bacteria. Genomic sequences have allowed the finding of two strains with a divergent structure related to the geographic region from where they were found. The isolates from the geographic collection of Southeast Asia and Mexico show variable regions on the plasmid genome, indicating that even though they are not alike they still conserve the toxin genes. In this paper, we report for the first time, a pathogenic V. parahaemolyticus strain in shrimp from South America that showed symptoms of AHPND. The genomic analysis revealed that this strain of V. parahaemolyticus found in South America appears to be more related to the Southeast Asia as compared to the Mexican strains. This finding is of major importance for the shrimp industry, especially in regards to the urgent need for disease control strategies to avoid large EMS outbreaks and economic loss, and to determine its dispersion in South America. The whole-genome shotgun project of V. parahaemolyticus strain Ba94C2 have been deposited at DDBJ/EMBL/GenBank under the accession PRJNA335761.

  18. The C2H2-type transcription factor, FlbC, is involved in the transcriptional regulation of Aspergillus oryzae glucoamylase and protease genes specifically expressed in solid-state culture.

    Science.gov (United States)

    Tanaka, Mizuki; Yoshimura, Midori; Ogawa, Masahiro; Koyama, Yasuji; Shintani, Takahiro; Gomi, Katsuya

    2016-07-01

    Aspergillus oryzae produces a large amount of secreted proteins in solid-state culture, and some proteins such as glucoamylase (GlaB) and acid protease (PepA) are specifically produced in solid-state culture, but rarely in submerged culture. From the disruption mutant library of A. oryzae transcriptional regulators, we successfully identified a disruption mutant showing an extremely low production level of GlaB but a normal level of α-amylase production. This strain was a disruption mutant of the C2H2-type transcription factor, FlbC, which is reported to be involved in the regulation of conidiospore development. Disruption mutants of other upstream regulators comprising a conidiation regulatory network had no apparent effect on GlaB production in solid-state culture. In addition to GlaB, the production of acid protease in solid-state culture was also markedly decreased by flbC disruption. Northern blot analyses revealed that transcripts of glaB and pepA were significantly decreased in the flbC disruption strain. These results suggested that FlbC is involved in the transcriptional regulation of genes specifically expressed under solid-state cultivation conditions, possibly independent of the conidiation regulatory network.

  19. Targeted gene delivery into peripheral sensorial neurons mediated by self-assembled vectors composed of poly(ethylene imine) and tetanus toxin fragment c.

    Science.gov (United States)

    Oliveira, Hugo; Fernandez, Ramon; Pires, Liliana R; Martins, M Cristina L; Simões, Sérgio; Barbosa, Mário A; Pêgo, Ana P

    2010-05-10

    A simple, safe and efficient system that can specifically transfect peripheral sensorial neurons can bring new answers to address peripheral neuropathies. A multi-component non-viral gene delivery vector targeted to peripheral nervous system cells was developed, using poly(ethylene imine) (PEI) as starting material. A binary DNA/polymer complex based on thiolated PEI (PEISH) was optimized, considering complex size and zeta potential and the ability to transfect a sensorial neuron cell line (ND7/23). The 50 kDa non-toxic fragment from tetanus toxin (HC), which has been previously shown to interact specifically with peripheral neurons and to undergo retrograde transport, was grafted to the complex core via a bifunctional PEG (HC-PEG) reactive for the thiol moieties present in the complex surface. Several formulations of HC-PEG ternary complexes were tested for targeting, by assessing the extent of cellular internalization and levels of transfection, in both the ND7/23 and NIH 3 T3 (fibroblast) cell lines. Targeted gene transfer to the neuronal cell line was observed for the complex formulations containing 5 and 7.5 microg of HC-PEG. Finally, our results demonstrate that the developed ternary vectors are able to transfect primary cultures of dorsal root ganglion dissociated neurons in a targeted manner and elicit the expression of a relevant neurotrophic factor. 2010 Elsevier B.V. All rights reserved.

  20. Immunogenicity and virulence of attenuated vaccinia virus Tian Tan encoding HIV-1 muti-epitope genes, p24 and cholera toxin B subunit in mice.

    Science.gov (United States)

    Du, Shouwen; Wang, Yuhang; Liu, Cunxia; Wang, Maopeng; Zhu, Yilong; Tan, Peng; Ren, Dayong; Li, Xiao; Tian, Mingyao; Yin, Ronglan; Li, Chang; Jin, Ningyi

    2015-07-01

    No effective prophylactic or therapeutic vaccine against HIV-1 in humans is currently available. This study analyzes the immunogenicity and safety of a recombinant attenuated vaccinia virus. A chimeric gene of HIV-1 multi-epitope genes containing CpG ODN and cholera toxin B subunit (CTB) was inserted into Chinese vaccinia virus Tian Tan strain (VTT) mutant strain. The recombinant virus rddVTT(-CCMp24) was assessed for immunogenicity and safety in mice. Results showed that the protein CCMp24 was expressed stably in BHK-21 infected with rddVTT(-CCMp24). And the recombinant virus induced the production of HIV-1 p24 specific immunoglobulin G (IgG), IL-2 and IL-4. The recombinant vaccine induced γ-interferon secretion against HIV peptides, and elicited a certain levels of immunological memory. Results indicated that the recombinant virus had certain immunogenicity to HIV-1. Additionally, the virulence of the recombinant virus was been attenuated in vivo of mice compared with wild type VTT (wtVTT), and the introduction of CTB and HIV Mp24 did not alter the infectivity and virulence of defective vaccinia virus. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. A cytolethal distending toxin gene-based multiplex PCR assay for detection of Campylobacter spp. in stool specimens and comparison with culture method.

    Science.gov (United States)

    Shiramaru, Sachi; Asakura, Masahiro; Inoue, Haruna; Nagita, Akira; Matsuhisa, Akio; Yamasaki, Shinji

    2012-07-01

    In this study, we evaluated the applicability of cytolethal distending toxin (cdt) gene-based species-specific multiplex PCR for the direct detection and identification of Campylobacter jejuni, C. coli and C. fetus from stool specimens of patients with gastroenteritis in comparison to culture methods. A total of 711 stool specimens were examined for the isolation or detection of campylobacters by using Skirrow's selective agar culture plates, a filtration method and the multiplex PCR assay. Forty-one and 36 C. jejuni strains were isolated by culture and filtration methods, respectively. In addition, 2 and 3 C. coli strains were isolated by Skirrow and the filtration methods, respectively. However, when the multiplex PCR was employed, the cdtB genes of C. jejuni and C. coli were detected in 45 and 4 stool samples, respectively, and 9 C. jejuni PCR-positive samples by multiplex PCR were negative by culture method. Sequence analysis of the PCR products obtained from 8 stool specimens from which campylobacters were not isolated by culture method but the sequences exactly matched with that of the cdtB gene of C. jejuni strain 81-176. None of the remaining stool samples which were culture negative for campylobacters produced any amplicon. Stool samples were defined as Campylobacter-positive if detected by any method. The sensitivity of the multiplex PCR was 83%, which was higher than Skirrow (74%) and filtration method (66%). These data indicate that cdtB gene-based multiplex PCR is a rapid and more sensitive method to identify the most important species of Campylobacter for human diseases. (248).

  2. Effects of feeding Bt MON810 maize to pigs for 110 days on peripheral immune response and digestive fate of the cry1Ab gene and truncated Bt toxin.

    Science.gov (United States)

    Walsh, Maria C; Buzoianu, Stefan G; Rea, Mary C; O'Donovan, Orla; Gelencsér, Eva; Ujhelyi, Gabriella; Ross, R Paul; Gardiner, Gillian E; Lawlor, Peadar G

    2012-01-01

    The objective of this study was to evaluate potential long-term (110 days) and age-specific effects of feeding genetically modified Bt maize on peripheral immune response in pigs and to determine the digestive fate of the cry1Ab gene and truncated Bt toxin. Forty day old pigs (n = 40) were fed one of the following treatments: 1) isogenic maize-based diet for 110 days (isogenic); 2) Bt maize-based diet (MON810) for 110 days (Bt); 3) Isogenic maize-based diet for 30 days followed by Bt maize-based diet for 80 days (isogenic/Bt); and 4) Bt maize-based diet (MON810) for 30 days followed by isogenic maize-based diet for 80 days (Bt/isogenic). Blood samples were collected during the study for haematological analysis, measurement of cytokine and Cry1Ab-specific antibody production, immune cell phenotyping and cry1Ab gene and truncated Bt toxin detection. Pigs were sacrificed on day 110 and digesta and organ samples were taken for detection of the cry1Ab gene and the truncated Bt toxin. On day 100, lymphocyte counts were higher (PBt/isogenic than pigs fed Bt or isogenic. Erythrocyte counts on day 100 were lower in pigs fed Bt or isogenic/Bt than pigs fed Bt/isogenic (PBt toxin nor the cry1Ab gene were detected in the organs or blood of pigs fed Bt maize. The cry1Ab gene was detected in stomach digesta and at low frequency in the ileum but not in the distal gastrointestinal tract (GIT), while the Bt toxin fragments were detected at all sites in the GIT. Perturbations in peripheral immune response were thought not to be age-specific and were not indicative of Th 2 type allergenic or Th 1 type inflammatory responses. There was no evidence of cry1Ab gene or Bt toxin translocation to organs or blood following long-term feeding.

  3. Prevalence of adhesin and toxin genes in E. coli strains isolated from diarrheic and non-diarrheic pigs from smallholder herds in northern and eastern Uganda.

    Science.gov (United States)

    Ikwap, Kokas; Larsson, Jenny; Jacobson, Magdalena; Owiny, David Okello; Nasinyama, George William; Nabukenya, Immaculate; Mattsson, Sigbrit; Aspan, Anna; Erume, Joseph

    2016-08-05

    Enterotoxigenic E. coli (ETEC) significantly contribute to diarrhea in piglets and weaners. The smallholder pig producers in Uganda identified diarrhea as one of the major problems especially in piglets. The aim of this study was to; i) characterize the virulence factors of E. coli strains isolated from diarrheic and non-diarrheic suckling piglets and weaners from smallholder herds in northern and eastern Uganda and ii) identify and describe the post-mortem picture of ETEC infection in severely diarrheic piglets. Rectal swab samples were collected from 83 piglets and weaners in 20 herds and isolated E. coli were characterized by PCR, serotyping and hemolysis. The E. coli strains carried genes for the heat stable toxins STa, STb and EAST1 and adhesins F4 and AIDA-I. The genes for the heat labile toxin LT and adhesins F5, F6, F18 and F41 were not detected in any of the E. coli isolates. Where the serogroup could be identified, E. coli isolates from the same diarrheic pig belonged to the same serogroup. The prevalence of EAST1, STb, Stx2e, STa, AIDA-I, and F4 in the E. coli isolates from suckling piglets and weaners (diarrheic and non-diarrheic combined) was 29, 26.5, 2.4, 1.2, 16, and 8.4 %, respectively. However the prevalence of F4 and AIDA-I in E. coli from diarrheic suckling piglets alone was 22.2 and 20 %, respectively. There was no significant difference in the prevalence of the individual virulence factors in E. coli from the diarrheic and non-diarrheic pigs (p > 0.05). The main ETEC strains isolated from diarrheic and non-diarrheic pigs included F4/STb/EAST1 (7.2 %), F4/STb (1.2 %), AIDA/STb/EAST1 (8 %) and AIDA/STb (8 %). At post-mortem, two diarrheic suckling piglets carrying ETEC showed intact intestinal villi, enterocytes and brush border but with a layer of cells attached to the brush border, suggestive of ETEC infections. This study has shown that the F4 fimbriae is the most predominant in E. coli from diarrheic piglets in the study area and

  4. Staphylococcal toxin genes in strains isolated from cows with subclinical mastitis Detecção de genes de toxinas em linhagens de estafilococos isolados de vacas com mastite subclínica

    Directory of Open Access Journals (Sweden)

    Manuela F.L. de Freitas

    2008-12-01

    Full Text Available The present study was carried out in 11 dairy herds in four municipal districts of the rural area of the State of Pernambuco, Brazil. Out of 984 quarter milk (246 cows, 10 (1.0% were positive for clinical mastitis, 562 (57.1% for subclinical mastitis and 412 (41.9% were negative. A total of 81 Staphylococcus spp. isolates were obtained from milk samples from the cows diagnosed with subclinical mastitis. From these, 53 (65.0% were S. aureus, 16 (20.0% coagulase-positive staphylococci (CPS and 12 (15.0% coagulase-negative staphylococci (CNS. The isolates were further investigated for the presence of toxin genes by multiplex and uniplex PCR. The main gene observed was seg followed by seh, sei and sej. The distribution of these observed genes among the isolates obtained from different areas showed a regional pattern for the SEs. The presence of toxin genes in the strains isolated from bovine milk demonstrates a potential problem for public health.O presente estudo foi realizado em 11 rebanhos leiteiros de quatro municípios da área rural do estado de Pernambuco, Brasil. Dos 984 quartos mamários examinados (246 vacas, 10 (1,0% foram positivos para a mastite clínica, 562 (57,1% para a mastite subclínica e 412 (41,9% foram negativos para mastite. Foram isoladas 81 linhagens de Staphylococcus spp. do leite de vacas com mastite subclínica. Destes, 53 (65,0% foram S. aureus, 16 (20,0% estafilococos coagulase-positivo (SCP e 12 (15,0% estafilococos coagulase-negativo (SCN. O principal gene observado nos estafilococos foi o seg seguido pelo seh, sei e sej. Foi constatada distribuição regional dos genes dos estafilococos isolados dos animais nos municípios estudados. A presença dos genes das toxinas nas linhagens isoladas do leite de vacas representa risco potencial para a Saúde Pública.

  5. Serotypes, virulence genes, and intimin types of shiga toxin-producing Escherichia coli and enteropathogenic Escherichia coli isolated from mastitic milk relevant to human health in Egypt.

    Science.gov (United States)

    Osman, Kamelia M; Mustafa, Ashgan M; Aly, Magdy A K; AbdElhamed, Ghada S

    2012-04-01

    Some foodborne pathogens can cause mastitis, in which the organism is directly excreted into milk. Therefore, we undertook the steps to determine the prevalence and molecular characteristics of Shiga toxin-producing Escherichia coli (STEC) isolates from bovine mastitic milk in Egypt. Forty milk samples from dairy cattle showing mastitis were collected and examined for the presence of E. coli. Following enrichment and plating on selective agar, confirmation of the isolates was based on biochemical tests and the isolates were determined at the species level using cytochrome oxidase, triple sugar iron agar, urea, and indole tests as putatively E. coli. About 77.4% of the isolates belonged to four different O serogroups (O26, O86, O111, and O127). The multiplex polymerase chain reaction (PCR) found that the seven isolates revealed positive amplification of the Eagg gene from the extracted DNA of the E. coli isolates in an incidence of 100%. Also, the selected isolates were subjected to a simple PCR for the detection of 12 of the most important E. coli genes associated with virulence. Those genes detected were stx1, stx2, hylA, Flic(h7), stb, F41, K99, sta, F17, LT-I, LT-II, and eaeA. A total of seven E. coli isolates that were non-O157 isolates were investigated. Among the seven isolates, none was stx positive, and all seven lacked F41, K99, LT-I, LT-II, and Flic(h7). Of these seven isolates, three (42.85%) were enterohemorrhagic E. coli hlyA positive and two (28.57%) were eaeA positive. STEC isolates were not found in bovine mastitic milk in Egypt. Isolates from mastitic milk were potentially pathogenic for human in that they belonged to serogroups associated with diarrhea and hemolytic-uremic syndrome, and some of them were hylA, stb, sta, F17, and eaeA positive.

  6. High Specificity of a Quantitative PCR Assay Targeting a Saxitoxin Gene for Monitoring Toxic Algae Associated with Paralytic Shellfish Toxins in the Yellow Sea.

    Science.gov (United States)

    Gao, Yan; Yu, Ren-Cheng; Murray, Shauna A; Chen, Jian-Hua; Kang, Zhen-Jun; Zhang, Qing-Chun; Kong, Fan-Zhou; Zhou, Ming-Jiang

    2015-10-01

    The identification of core genes involved in the biosynthesis of saxitoxin (STX) offers a great opportunity to detect toxic algae associated with paralytic shellfish toxins (PST). In the Yellow Sea (YS) in China, both toxic and nontoxic Alexandrium species are present, which makes it a difficult issue to specifically monitor PST-producing toxic algae. In this study, a quantitative PCR (qPCR) assay targeting sxtA4, a domain in the sxt gene cluster that encodes a unique enzyme involved in STX biosynthesis, was applied to analyze samples collected from the YS in spring of 2012. The abundance of two toxic species within the Alexandrium tamarense species complex, i.e., A. fundyense and A. pacificum, was also determined with TaqMan-based qPCR assays, and PSTs in net-concentrated phytoplankton samples were analyzed with high-performance liquid chromatography coupled with a fluorescence detector. It was found that the distribution of the sxtA4 gene in the YS was consistent with the toxic algae and PSTs, and the quantitation results of sxtA4 correlated well with the abundance of the two toxic species (r=0.857). These results suggested that the two toxic species were major PST producers during the sampling season and that sxtA-based qPCR is a promising method to detect toxic algae associated with PSTs in the YS. The correlation between PST levels and sxtA-based qPCR results, however, was less significant (r=0.552), implying that sxtA-based qPCR is not accurate enough to reflect the toxicity of PST-producing toxic algae. The combination of an sxtA-based qPCR assay and chemical means might be a promising method for monitoring toxic algal blooms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Neuroprotective effect of non-viral gene therapy treatment based on tetanus toxin C-fragment in a severe mouse model of Spinal Muscular Atrophy.

    Directory of Open Access Journals (Sweden)

    Sara Olivan Garcia

    2016-08-01

    Full Text Available Spinal muscular atrophy (SMA is a hereditary childhood disease that causes paralysis and progressive degeneration of skeletal muscles and spinal motor neurons. SMA is associated with reduced levels of full-length Survival of Motor Neuron (SMN protein, due to mutations in the Survival of Motor Neuron 1 gene. Nowadays there are no effective therapies available to treat patients with SMA, so our aim was to test whether the non-toxic carboxy-terminal fragment of tetanus toxin heavy chain (TTC, which exhibits neurotrophic properties, might have a therapeutic role or benefit in SMA. In this manuscript, we have demonstrated that TTC enhance the SMN expression in motor neurons in vitro and evaluated the effect of intramuscular injection of TTC-encoding plasmid in the spinal cord and the skeletal muscle of SMNdelta7 mice. For this purpose, we studied the weight and the survival time, as well as, the survival and cell death pathways and muscular atrophy. Our results showed that TTC treatment reduced the expression of autophagy markers (Becn1, Atg5, Lc3 and p62 and pro-apoptotic genes such as Bax and Casp3 in spinal cord. In skeletal muscle, TTC was able to downregulate the expression of the main marker of autophagy, Lc3, to wild type levels and the expression of the apoptosis effector protein, Casp3. Regarding the genes related to muscular atrophy (Ankrd1, Calm1, Col19a1, Fbox32, Mt2, Myod1, NogoA, Pax7, Rrad, and Sln, TTC suggest a compensatory effect for muscle damage response, diminished oxidative stress and modulated calcium homeostasis. These preliminary findings suggest the need for further experiments to depth study the effect of TTC in SMA disease.

  8. Survival and expression of acid resistance genes in Shiga toxin-producing Escherichia coli acid adapted in pineapple juice and exposed to synthetic gastric fluid.

    Science.gov (United States)

    Kim, G-H; Fratamico, P; Breidt, F; Oh, D-H

    2016-11-01

    The aim of this research was to determine the ability of non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups to survive with exposure to synthetic gastric fluid (SGF) after adaptation to pineapple juice (PJ) at room and refrigerated temperatures compared to E. coli O157:H7 and to examine the relative transcriptional expression of acid resistance (AR) genes, rpoS, gadA and adiA. Resistant and sensitive strains belonging to five different STEC serogroups (O26, O103, O104, O111 and O157; n = 10) were used in this study. All strains were adapted in PJ (pH 3·8) stored at 4 and 20°C for 24 h, and then the relative transcription levels of genes in all strains were quantified using a real-time quantitative-PCR assay. After adaptation in PJ, the STEC strains were exposed to SGF (pH 1·5 and 2·0) at 37°C for 2 h. Generally, the STEC adapted in PJ at 4°C displayed enhanced survival compared to acid adaptation in PJ at 20°C and nonadapted controls with exposure to SGF (P < 0·05). Moreover, resistant strains exhibited higher survival rates compared to sensitive strains (P < 0·05). Overall, adaptation at 4°C resulted in significantly (P < 0·05) enhanced gene expression levels in PJ, and transcript levels of gadA were higher than those of the rpoS and adiA genes. The up-regulation of AR genes due to adaptation in PJ at low temperature may increase STEC survival in acidic environments such as the gastrointestinal tract. Some non-O157 STEC strains, including serotypes O103:H2 and O111:H8, showed relatively high AR levels similar to those of STEC O157:H7. Induction of AR genes in acidic fruit juice, and potentially in other acidic foods may increase the risk of foodborne illness by non-O157 STEC serogroups. © 2016 The Society for Applied Microbiology.

  9. Bullous Impetigo in Children Infected with Methicillin-Resistant Staphylococcus aureus Alone or in Combination with Methicillin-Susceptible S. aureus: Analysis of Genetic Characteristics, Including Assessment of Exfoliative Toxin Gene Carriage▿

    Science.gov (United States)

    Shi, Da; Higuchi, Wataru; Takano, Tomomi; Saito, Kohei; Ozaki, Kyoko; Takano, Misao; Nitahara, Yoshiyuki; Yamamoto, Tatsuo

    2011-01-01

    Among bullous impetigo isolates, exfoliative toxin (ET) gene carriage was found in 61.5% of methicillin-resistant Staphylococcus aureus (MRSA) isolates versus 90.6% of methicillin-susceptible S. aureus (MSSA) isolates. MRSA-only cases were ETB or ETA positive, while MRSA/MSSA coinfection cases were ET negative for MRSA but ETA positive for MSSA. Collagen adhesin may facilitate some MRSA infections. PMID:21430094

  10. Inactivation of allergens and toxins.

    Science.gov (United States)

    Morandini, Piero

    2010-11-30

    Plants are replete with thousands of proteins and small molecules, many of which are species-specific, poisonous or dangerous. Over time humans have learned to avoid dangerous plants or inactivate many toxic components in food plants, but there is still room for ameliorating food crops (and plants in general) in terms of their allergens and toxins content, especially in their edible parts. Inactivation at the genetic rather than physical or chemical level has many advantages and classical genetic approaches have resulted in significant reduction of toxin content. The capacity, offered by genetic engineering, of turning off (inactivating) specific genes has opened up the possibility of altering the plant content in a far more precise manner than previously available. Different levels of intervention (genes coding for toxins/allergens or for enzymes, transporters or regulators involved in their metabolism) are possible and there are several tools for inactivating genes, both direct (using chemical and physical mutagens, insertion of transposons and other genetic elements) and indirect (antisense RNA, RNA interference, microRNA, eventually leading to gene silencing). Each level/strategy has specific advantages and disadvantages (speed, costs, selectivity, stability, reversibility, frequency of desired genotype and regulatory regime). Paradigmatic examples from classical and transgenic approaches are discussed to emphasize the need to revise the present regulatory process. Reducing the content of natural toxins is a trade-off process: the lesser the content of natural toxins, the higher the susceptibility of a plant to pests and therefore the stronger the need to protect plants. As a consequence, more specific pesticides like Bt are needed to substitute for general pesticides. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Occurrence of a stonefish toxin-like toxin in the venom of the rabbitfish Siganus fuscescens.

    Science.gov (United States)

    Kiriake, Aya; Ishizaki, Shoichiro; Nagashima, Yuji; Shiomi, Kazuo

    2017-12-15

    Rabbitfish belonging to the order Perciformes are well-known venomous fish that are frequently involved in human accidents. However little research has been done into either the whole venom toxicities or the structures and properties of their venom toxins. In this study, we first examined biological activities of the crude venom extract prepared from dorsal spines of Siganus fuscescens, a rabbitfish most commonly found along the coasts of Japan. As a result, the crude venom extract was shown to have mouse-lethal activity, hemolytic activity against rabbit erythrocytes, edema-forming activity and nociceptive activity, similar to the known scorpaeniform fish toxins (stonefish toxins and their analogues). Then, the primary structure of the S. fuscescens toxin was successfully elucidated by the same cDNA cloning strategy as previously employed for the toxins of some scorpaeniform fish (lionfish, devil stinger and waspfish). The S. fuscescens toxin is obviously an analogue of stonefish toxins, being composed of two kinds of subunits, an α-subunit of 703 amino acid residues and a β-subunit of 699 amino acid residues. Furthermore, the genes encoding both subunits were cloned from genomic DNA and shown to have an architecture of three exons and two introns, as reported for those of the scorpaeniform fish toxins. This study is the first to demonstrate the occurrence of stonefish toxin-like toxins in perciform fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Bordetella Adenylate Cyclase-Hemolysin Toxins

    Science.gov (United States)

    Guiso, Nicole

    2017-01-01

    Adenylate cyclase-hemolysin toxin is secreted and produced by three classical species of the genus Bordetella: Bordetella pertussis, B. parapertussis and B. bronchiseptica. This toxin has several properties such as: (i) adenylate cyclase activity, enhanced after interaction with the eukaryotic protein, calmodulin; (ii) a pore-forming activity; (iii) an invasive activity. It plays an important role in the pathogenesis of these Bordetella species responsible for whooping cough in humans or persistent respiratory infections in mammals, by modulating host immune responses. In contrast with other Bordetella toxins or adhesins, lack of (or very low polymorphism) is observed in the structural gene encoding this toxin, supporting its importance as well as a potential role as a vaccine antigen against whooping cough. In this article, an overview of the investigations undertaken on this toxin is presented. PMID:28892012

  13. Nucleotide sequence of the streptococcal pyrogenic exotoxin type B gene and relationship between the toxin and the streptococcal proteinase precursor.

    OpenAIRE

    Hauser, A R; Schlievert, P M

    1990-01-01

    The streptococcal pyrogenic exotoxin (SPE) type B-encoding structural gene, speB, was subcloned from a 4.5-kilobase streptococcal DNA insert onto a 2.4-kilobase insert, which was then sequenced. Studies indicated that a 1,194-base-pair open reading frame encoded a 398-amino-acid protein. Removal of the putative signal peptide resulted in a mature protein with 371 residues (molecular weight, 40,314), which was subsequently proteolyzed to yield a 253-residue breakdown product (molecular weight,...

  14. C2 metabolism in Euglena.

    Science.gov (United States)

    Nakazawa, Masami

    2017-01-01

    Euglenoids are able to assimilate fatty acids and alcohols with various carbon-chain lengths, and ethanol is known to be one of the best carbon sources to support the growth of Euglena gracilis. Ethanol is first oxidized to acetate by the sequential reactions of alcohol dehydrogenase and acetaldehyde dehydrogenase in the mitochondria, and then converted to acetyl coenzyme A (acetyl-CoA). Acetyl-CoA is metabolized through the glyoxylate cycle which is a modified tricarboxylic acid (TCA) cycle in which isocitrate lyase (ICL) and malate synthase (MS) function to bypass the two decarboxylation steps of the TCA cycle, enabling the net synthesis of carbohydrates from C2 compounds. ICL and MS form a unique bifunctional enzyme localized in Euglena mitochondria, not in glyoxysome as in other eukaryotes. The unique glyoxylate and glycolate metabolism during photorespiration is also discussed in this chapter.

  15. Detection of E.Coli Strains Containing Shiga Toxin (Stx1/2 Gene in Diarrheal Specimens from Children Less than 5 Years Old by PCR Technique and Study of the Patterns of Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    MR Pourmand

    2009-10-01

    Full Text Available Introduction: Shiga toxin- producing Escherichia coli (STEC is an emerging bacterial pathogen in developing countries that causes several diseases such as diarrhea, hemorrhagic colitis (HC and hemolytic uremic syndrome (HUS, particularly in children. Aim of the research was detection of STEC in diarrheal specimens from under 5 year olds and study of the patterns of antibiotic resistance of these strains. Methods: In the study,300 fecal samples were collected from children with diarrhea referring to Ali Asghar Hospital. E.coli species were isolated by standard bacteriological and biochemical tests. Presence of shiga toxin genes (stx1/2 was investigated by PCR technique (Qiagen. Antibiogram test for strains containing the toxin gene was performed using 16 different antibiotic discs (MAST by disc diffusion agar (Kirby-Bauer method. Results: From 39 E.coli isolates, 9(23.1% strains were detected by PCR to contain stx1/2 gene. One strain was resistant to all 16 antibiotics. All the STEC strains were sensitive to meropenem (MRP, imipenem (IMI, gentamycin (GEN and nitrofurantoin (NI. 4(44.44% strains showed multi-drug resistant pattern. All these 4strains were resistant to cotrimoxazole(SxT. Also, 6(66.66% strains were resistant to at least one antibiotic. Conclusion: In Iran, shiga toxin- producing Escherichia coli (STEC may be a commonly bacterial pathogen causing diarrhea, particularly in children. Therefore, we should use new techniques for investigation of these strains. Increase in number of emerging and new strains that could be resistant to classic antibiotics such as cotrimoxazole may be foreseen. It is suggested that antibiotics prescription programs in treatment of diarrhea causing E.coli strains be updated.

  16. Malonyl-CoA decarboxylase (MCD) is differentially regulated in subcellular compartments by 5'AMP-activated protein kinase (AMPK). Studies using H9c2 cells overexpressing MCD and AMPK by adenoviral gene transfer technique.

    Science.gov (United States)

    Sambandam, Nandakumar; Steinmetz, Michael; Chu, Angel; Altarejos, Judith Y; Dyck, Jason R B; Lopaschuk, Gary D

    2004-07-01

    Malonyl-CoA, a potent inhibitor of carnitine pamitoyl transferase-I (CPT-I), plays a pivotal role in fuel selection in cardiac muscle. Malonyl-CoA decarboxylase (MCD) catalyzes the degradation of malonyl-CoA, removes a potent allosteric inhibition on CPT-I and thereby increases fatty acid oxidation in the heart. Although MCD has several Ser/Thr phosphorylation sites, whether it is regulated by AMP-activated protein kinase (AMPK) has been controversial. We therefore overexpressed MCD (Ad.MCD) and constitutively active AMPK (Ad.CA-AMPK) in H9c2 cells, using an adenoviral gene delivery approach in order to examine if MCD is regulated by AMPK. Cells infected with Ad.CA-AMPK demonstrated a fourfold increase in AMPK activity as compared with control cells expressing green fluorescent protein (Ad.GFP). MCD activity increased 40- to 50-fold in Ad.MCD + Ad.GFP cells when compared with Ad.GFP control. Co-expressing AMPK with MCD further augmented MCD expression and activity in Ad.MCD + Ad.CA-AMPK cells compared with the Ad.MCD + Ad.GFP control. Subcellular fractionation further revealed that 54.7 kDa isoform of MCD expression was significantly higher in cytosolic fractions of Ad.MCD + Ad.CA-AMPK cells than of the Ad.MCD +Ad.GFP control. However, the MCD activities in cytosolic fractions were not different between the two groups. Interestingly, in the mitochondrial fractions, MCD activity significantly increased in Ad.MCD + Ad.CA-AMPK cells when compared with Ad.MCD + Ad.GFP cells. Using phosphoserine and phosphothreonine antibodies, no phosphorylation of MCD by AMPK was observed. The increase in MCD activity in mitochondria-rich fractions of Ad.MCD + Ad.CA-AMPK cells was accompanied by an increase in the level of the 50.7 kDa isoform of MCD protein in the mitochondria. This differential regulation of MCD expression and activity in the mitochondria by AMPK may potentially regulate malonyl-CoA levels at sites nearby CPT-I on the mitochondria.

  17. Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich

    National Research Council Canada - National Science Library

    Ostermaier, Veronika; Schanz, Ferdinand; Köster, Oliver; Kurmayer, Rainer

    2012-01-01

    Harmful algal blooms deteriorate the services of aquatic ecosystems. They are often formed by cyanobacteria composed of genotypes able to produce a certain toxin, for example, the hepatotoxin microcystin (MC...

  18. Anthrax lethal toxin rapidly reduces c-Jun levels by inhibiting c-Jun gene transcription and promoting c-Jun protein degradation.

    Science.gov (United States)

    Ouyang, Weiming; Guo, Pengfei; Fang, Hui; Frucht, David M

    2017-10-27

    Anthrax is a life-threatening disease caused by infection with Bacillus anthracis , which expresses lethal factor and the receptor-binding protective antigen. These two proteins combine to form anthrax lethal toxin (LT), whose proximal targets are mitogen-activated kinase kinases (MKKs). However, the downstream mediators of LT toxicity remain elusive. Here we report that LT exposure rapidly reduces the levels of c-Jun, a key regulator of cell proliferation and survival. Blockade of proteasome-dependent protein degradation with the 26S proteasome inhibitor MG132 largely restored c-Jun protein levels, suggesting that LT promotes degradation of c-Jun protein. Using the MKK1/2 inhibitor U0126, we further show that MKK1/2-Erk1/2 pathway inactivation similarly reduces c-Jun protein, which was also restored by MG132 pre-exposure. Interestingly, c-Jun protein rebounded to normal levels 4 h following U0126 exposure but not after LT exposure. The restoration of c-Jun in U0126-exposed cells was associated with increased c-Jun mRNA levels and was blocked by inactivation of the JNK1/2 signaling pathway. These results indicate that LT reduces c-Jun both by promoting c-Jun protein degradation via inactivation of MKK1/2-Erk1/2 signaling and by blocking c-Jun gene transcription via inactivation of MKK4-JNK1/2 signaling. In line with the known functions of c-Jun, LT also inhibited cell proliferation. Ectopic expression of LT-resistant MKK2 and MKK4 variants partially restored Erk1/2 and JNK1/2 signaling in LT-exposed cells, enabling the cells to maintain relatively normal c-Jun protein levels and cell proliferation. Taken together, these findings indicate that LT reduces c-Jun protein levels via two distinct mechanisms, thereby inhibiting critical cell functions, including cellular proliferation.

  19. Discovery of novel bacterial toxins by genomics and computational biology.

    Science.gov (United States)

    Doxey, Andrew C; Mansfield, Michael J; Montecucco, Cesare

    2018-02-10

    Hundreds and hundreds of bacterial protein toxins are presently known. Traditionally, toxin identification begins with pathological studies of bacterial infectious disease. Following identification and cultivation of a bacterial pathogen, the protein toxin is purified from the culture medium and its pathogenic activity is studied using the methods of biochemistry and structural biology, cell biology, tissue and organ biology, and appropriate animal models, supplemented by bioimaging techniques. The ongoing and explosive development of high-throughput DNA sequencing and bioinformatic approaches have set in motion a revolution in many fields of biology, including microbiology. One consequence is that genes encoding novel bacterial toxins can be identified by bioinformatic and computational methods based on previous knowledge accumulated from studies of the biology and pathology of thousands of known bacterial protein toxins. Starting from the paradigmatic cases of diphtheria toxin, tetanus and botulinum neurotoxins, this review discusses traditional experimental approaches as well as bioinformatics and genomics-driven approaches that facilitate the discovery of novel bacterial toxins. We discuss recent work on the identification of novel botulinum-like toxins from genera such as Weissella, Chryseobacterium, and Enteroccocus, and the implications of these computationally identified toxins in the field. Finally, we discuss the promise of metagenomics in the discovery of novel toxins and their ecological niches, and present data suggesting the existence of uncharacterized, botulinum-like toxin genes in insect gut metagenomes. Copyright © 2018. Published by Elsevier Ltd.

  20. Sekuen Nukleotida Gene Shiga like toxin-2 dari Isolat Lokal Escherichia coli O157:H7 asal Hewan dan Manusia (NUCLEOTIDES SQUENCES OF SHIGA-LIKE TOXIN 2 GENES OF ESCHERICHIA COLI O157:H7 LOCAL ISOLATES ORIGINATED FROM ANIMALS AND HUMAN

    Directory of Open Access Journals (Sweden)

    I Wayan Suardana

    2017-04-01

    Full Text Available Animals/livestock, especially cattle, are known as the main reservoir of Escherichia coli O157: H7. As theonly one of zoonotic E. coli, the pathogenicity of these bacteria is determined by its ability to produce oneor more very potent cytotoxin known as Shiga-like toxin (Stx or verocytotoxin, particularly of the Stx2 typethat is closely related to the incidence of hemolytic uremic syndrome (HUS in humans. This study analyzedthe nucleotide sequences of stx2 gene between isolates from animals and humans in an effort to assess thepotential zoonoses of the agent. The research activity was initiated by cultivating 20 isolates of E. coliO157:H7 collection based on result in the previous study i.e. 2 isolates originated from cattle feces, 2isolates originated from beef, 2 isolates originated from chicken feces, 2 isolates originated from humanfaeces and 12 non-clinical isolates originated from human fecal who were suffering with renal failure. Allisolates were confirmed on selective medium Sorbitol MacConkey Agar (SMAC followed by testing onaglutination O157 latex test, and H7 antisera. Molecular analysis of stx2 gene covering open reading frame (ORF of the stx2 gene was performed using the primer which was designed by researcher i.e. Stx2 (F/ Stx2 (R. The results showed, there were 2 isolates i.e. KL-48 (2 originated from human feces and SM-25(1 originated from cattle feces were positive for carrying a stx2 gene, which was marked by the 1587 bpPCR product. Analysis of sequencing showed both isolates had identical to stx2 nucleotide squences withE. phaga 933 as well as E. coli ATCC 933. These results indicate the both local isolates are potential aszoonotic agents with clinical effects similar to E. phaga 933 and E. coli ATCC 43894

  1. Sensitive quantification of Clostridium perfringens in human feces by quantitative real-time PCR targeting alpha-toxin and enterotoxin genes.

    Science.gov (United States)

    Nagpal, Ravinder; Ogata, Kiyohito; Tsuji, Hirokazu; Matsuda, Kazunori; Takahashi, Takuya; Nomoto, Koji; Suzuki, Yoshio; Kawashima, Kazunari; Nagata, Satoru; Yamashiro, Yuichiro

    2015-10-19

    Clostridium perfringens is a widespread pathogen, but the precise quantification of this subdominant gut microbe remains difficult due to its low fecal count (particularly in asymptomatic subjects) and also due to the presence of abundant polymerase-inhibitory substances in human feces. Also, information on the intestinal carriage of toxigenic C. perfringens strains in healthy subjects is sparse. Therefore, we developed a sensitive quantitative real-time PCR assays for quantification of C. perfringens in human feces by targeting its α-toxin and enterotoxin genes. To validate the assays, we finally observed the occurrence of α-toxigenic and enterotoxigenic C. perfringens in the fecal microbiota of healthy Japanese infants and young adults. The plc-specific qPCR assay was newly validated, while primers for 16S rRNA and cpe genes were retrieved from literature. The assays were validated for specificity and sensitivity in pre-inoculated fecal samples, and were finally applied to quantify C. perfringens in stool samples from apparently healthy infants (n 124) and young adults (n 221). The qPCR assays were highly specific and sensitive, with a minimum detection limit of 10(3) bacterial cells/g feces. Alpha-toxigenic C. perfringens was detected in 36% infants and 33% adults, with counts ranging widely (10(3)-10(7) bacterial cells/g). Intriguingly, the mean count of α-toxigenic C. perfringens was significantly higher in infants (6.0±1.5 log10 bacterial cells/g), as compared to that in adults (4.8±1.2). Moreover, the prevalence of enterotoxigenic C. perfringens was also found to be significantly higher in infants, as compared to that in adults. The mean enterotoxigenic C. perfringens count was 5.9±1.9 and 4.8±0.8 log10 bacterial cells/g in infants and adults, respectively. These data indicate that some healthy infants and young adults carry α-toxigenic and enterotoxigenic C. perfringens at significant levels, and may be predisposed to related diseases. Thus, high

  2. Quality and safety evaluation of genetically modified potatoes spunta with Cry V gene: compositional analysis, determination of some toxins, antinutrients compounds and feeding study in rats.

    Science.gov (United States)

    El Sanhoty, Rafaat; El-Rahman, Ahamed Ali Abd; Bögl, Klaus Werner

    2004-02-01

    The aim of this study was to evaluate the composition, nutritional and toxicology safety of GM potato Spunta lines compared to that of conventional potato Spunta. Compositional analyses were conducted to measure the proximate chemical composition with references to 14 components, total solid, protein, lipid, crude fibre, ash, carbohydrate, starch, reducing sugar, nonreducing sugar, sodium, calcium, potassium, phosphorus, and ascorbic acid. Some toxins and anti-nutrients compounds were determined. Feeding study of GM potatoes line (G2 and G3) in rats were done for 30 days. Four groups of albino rats were used for studying the effect and the safety assessment of GM potatoes Spunta G2 and G3. Group (I) was fed on control basal diet, group (II) was fed on control diet plus 30% freeze-dried nongenetically modified potato Spunta, group (III) was fed on control diet plus 30% freeze-dried genetically modified potato Spunta, and group (IV) was fed on control diet plus 30% freeze-dried genetically modified potato Spunta GMO G3. There were no significant differences between GM potatoes G2, G3, and Spunta control potato line in the proximate chemical composition. The levels of glycoalkaloids in transgenic potato tubers and nontransgenic were determined and there were also no significant differences between the GM potatoes and conventional potato line, the levels were in agreement with a safety level recommended by FAO/WHO (200 mg/ kg) for acute toxicity. Protease inhibitor activity and total phenol were estimated and no significant differences between the GM potatoes line and conventional potato Spunta line were found. During the period tested, rats in each group (I, II, III, IV) grew well without marked differences in appearance. No statistical difference were found in food intake, daily body weight gain and feed efficiency. But there is a slightly significant difference in finally body weight between the control group and experimental groups. No significant difference were

  3. Sea anemone (Cnidaria, Anthozoa, Actiniaria) toxins: an overview.

    Science.gov (United States)

    Frazão, Bárbara; Vasconcelos, Vitor; Antunes, Agostinho

    2012-08-01

    The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors) and non-proteinaceous substances (purines, quaternary ammonium compounds, biogenic amines and betaines), but very few genes encoding toxins were described and only a few related protein three-dimensional structures are available. Toxins are used for prey acquisition, but also to deter potential predators (with neurotoxicity and cardiotoxicity effects) and even to fight territorial disputes. Cnidaria toxins have been identified on the nematocysts located on the tentacles, acrorhagi and acontia, and in the mucous coat that covers the animal body. Sea anemone toxins comprise mainly proteins and peptides that are cytolytic or neurotoxic with its potency varying with the structure and site of action and are efficient in targeting different animals, such as insects, crustaceans and vertebrates. Sea anemones toxins include voltage-gated Na⁺ and K⁺ channels toxins, acid-sensing ion channel toxins, Cytolysins, toxins with Kunitz-type protease inhibitors activity and toxins with Phospholipase A2 activity. In this review we assessed the phylogentic relationships of sea anemone toxins, characterized such toxins, the genes encoding them and the toxins three-dimensional structures, further providing a state-of-the-art description of the procedures involved in the isolation and purification of bioactive toxins.

  4. Sea Anemone (Cnidaria, Anthozoa, Actiniaria Toxins: An Overview

    Directory of Open Access Journals (Sweden)

    Agostinho Antunes

    2012-08-01

    Full Text Available The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors and non-proteinaceous substances (purines, quaternary ammonium compounds, biogenic amines and betaines, but very few genes encoding toxins were described and only a few related protein three-dimensional structures are available. Toxins are used for prey acquisition, but also to deter potential predators (with neurotoxicity and cardiotoxicity effects and even to fight territorial disputes. Cnidaria toxins have been identified on the nematocysts located on the tentacles, acrorhagi and acontia, and in the mucous coat that covers the animal body. Sea anemone toxins comprise mainly proteins and peptides that are cytolytic or neurotoxic with its potency varying with the structure and site of action and are efficient in targeting different animals, such as insects, crustaceans and vertebrates. Sea anemones toxins include voltage-gated Na+ and K+ channels toxins, acid-sensing ion channel toxins, Cytolysins, toxins with Kunitz-type protease inhibitors activity and toxins with Phospholipase A2 activity. In this review we assessed the phylogentic relationships of sea anemone toxins, characterized such toxins, the genes encoding them and the toxins three-dimensional structures, further providing a state-of-the-art description of the procedures involved in the isolation and purification of bioactive toxins.

  5. [Hemolysis of Scolopendra toxins].

    Science.gov (United States)

    Deng, F; Fang, H; Wang, K

    1997-01-01

    The hemolysis of toxins from alive Scolopendra subspinipes mutilans, medicinal material of Scolopendra subspimipes mutilans and S. multidens have been compared. The result shows that all the toxins have hemolytic activity. The hemolytic activity of the toxin from the medicinal materials of S. subspinipes mutilans is obviously lower than that from alive ones, and that from fresh medicinal materials are twice as high that from old ones, and that from S. multidens is higher than that from S. subspinipes multilans.

  6. Regulation of Toxin Production in Clostridium perfringens.

    Science.gov (United States)

    Ohtani, Kaori; Shimizu, Tohru

    2016-07-05

    The Gram-positive anaerobic bacterium Clostridium perfringens is widely distributed in nature, especially in soil and the gastrointestinal tracts of humans and animals. C. perfringens causes gas gangrene and food poisoning, and it produces extracellular enzymes and toxins that are thought to act synergistically and contribute to its pathogenesis. A complicated regulatory network of toxin genes has been reported that includes a two-component system for regulatory RNA and cell-cell communication. It is necessary to clarify the global regulatory system of these genes in order to understand and treat the virulence of C. perfringens. We summarize the existing knowledge about the regulatory mechanisms here.

  7. Regulation of Toxin Production in Clostridium perfringens

    Directory of Open Access Journals (Sweden)

    Kaori Ohtani

    2016-07-01

    Full Text Available The Gram-positive anaerobic bacterium Clostridium perfringens is widely distributed in nature, especially in soil and the gastrointestinal tracts of humans and animals. C. perfringens causes gas gangrene and food poisoning, and it produces extracellular enzymes and toxins that are thought to act synergistically and contribute to its pathogenesis. A complicated regulatory network of toxin genes has been reported that includes a two-component system for regulatory RNA and cell-cell communication. It is necessary to clarify the global regulatory system of these genes in order to understand and treat the virulence of C. perfringens. We summarize the existing knowledge about the regulatory mechanisms here.

  8. Regulation of Toxin Production in Clostridium perfringens

    Science.gov (United States)

    Ohtani, Kaori; Shimizu, Tohru

    2016-01-01

    The Gram-positive anaerobic bacterium Clostridium perfringens is widely distributed in nature, especially in soil and the gastrointestinal tracts of humans and animals. C. perfringens causes gas gangrene and food poisoning, and it produces extracellular enzymes and toxins that are thought to act synergistically and contribute to its pathogenesis. A complicated regulatory network of toxin genes has been reported that includes a two-component system for regulatory RNA and cell-cell communication. It is necessary to clarify the global regulatory system of these genes in order to understand and treat the virulence of C. perfringens. We summarize the existing knowledge about the regulatory mechanisms here. PMID:27399773

  9. Differential Requirement for the Translocation of Clostridial Binary Toxins: Iota Toxin Requires a Membrane Potential Gradient

    Science.gov (United States)

    2007-02-28

    chlorpromazin (Chp), filipinIII, nigericin (Ni), con- canamycin (Con), ammonium chloride, and nocodazole were from Sig- ma. 2.2. Bacterial strains and toxin...fluid before recording the radioactivity. Results are expressed as a percentage of inhibited protein synthesis rel- ative to control preparations not...5 nM) (D) as measured by inhibition of protein synthesis in Vero cells. Data are means ± S.D. (n = 5). 10-9 10-7 0 20 40 60 80 100 C2 toxin (log M) F

  10. Comparison of BD GeneOhm Cdiff real-time PCR assay with a two-step algorithm and a toxin A/B enzyme-linked immunosorbent assay for diagnosis of toxigenic Clostridium difficile infection.

    Science.gov (United States)

    Kvach, Elizabeth J; Ferguson, David; Riska, Paul F; Landry, Marie L

    2010-01-01

    The BD GeneOhm Cdiff assay, a real-time PCR assay for the detection of the Clostridium difficile toxin B (tcdB) gene, was compared with the toxin A/B (Tox A/B) II enzyme-linked immunosorbent assay (ELISA) and a two-step algorithm which includes a C. Diff Chek-60 glutamate dehydrogenase (GDH) antigen assay followed by cytotoxin neutralization. Four hundred liquid or semisolid stool samples submitted for diagnostic C. difficile testing, 200 GDH antigen positive and 200 GDH antigen negative, were selected for analysis. All samples were tested by the C. Diff Chek-60 GDH antigen and cytotoxin neutralization assays, the Tox A/B II ELISA, and the BD GeneOhm Cdiff assay. Specimens with discrepant results were tested by toxigenic culture as an independent "gold standard." Of 200 GDH-positive samples, 71 were positive by the Tox A/B II ELISA, 88 were positive by the two-step method, 93 were positive by PCR, and 96 were positive by the GDH antigen assay only. Of 200 GDH-negative samples, 3 were positive by PCR only. Toxigenic culture was performed for 41 samples with discrepant results, and 39 were culture positive. Culture resolution of discrepant results showed the Tox A/B II assay to have detected 70 (66.7%), the two-step method to have detected 87 (82.9%), and PCR to have detected 96 (91.4%) of 105 true positives. The BD GeneOhm Cdiff assay was more sensitive in detecting toxigenic C. difficile than the Tox A/B II assay (P < 0.0001); however, the difference between PCR and the two-step method was not significant (P = 0.1237). Enhanced sensitivity and rapid turnaround time make the BD GeneOhm Cdiff assay an important advance in the diagnosis of toxigenic C. difficile infection.

  11. Comparison of BD GeneOhm Cdiff Real-Time PCR Assay with a Two-Step Algorithm and a Toxin A/B Enzyme-Linked Immunosorbent Assay for Diagnosis of Toxigenic Clostridium difficile Infection▿

    Science.gov (United States)

    Kvach, Elizabeth J.; Ferguson, David; Riska, Paul F.; Landry, Marie L.

    2010-01-01

    The BD GeneOhm Cdiff assay, a real-time PCR assay for the detection of the Clostridium difficile toxin B (tcdB) gene, was compared with the toxin A/B (Tox A/B) II enzyme-linked immunosorbent assay (ELISA) and a two-step algorithm which includes a C. Diff Chek-60 glutamate dehydrogenase (GDH) antigen assay followed by cytotoxin neutralization. Four hundred liquid or semisolid stool samples submitted for diagnostic C. difficile testing, 200 GDH antigen positive and 200 GDH antigen negative, were selected for analysis. All samples were tested by the C. Diff Chek-60 GDH antigen and cytotoxin neutralization assays, the Tox A/B II ELISA, and the BD GeneOhm Cdiff assay. Specimens with discrepant results were tested by toxigenic culture as an independent “gold standard.” Of 200 GDH-positive samples, 71 were positive by the Tox A/B II ELISA, 88 were positive by the two-step method, 93 were positive by PCR, and 96 were positive by the GDH antigen assay only. Of 200 GDH-negative samples, 3 were positive by PCR only. Toxigenic culture was performed for 41 samples with discrepant results, and 39 were culture positive. Culture resolution of discrepant results showed the Tox A/B II assay to have detected 70 (66.7%), the two-step method to have detected 87 (82.9%), and PCR to have detected 96 (91.4%) of 105 true positives. The BD GeneOhm Cdiff assay was more sensitive in detecting toxigenic C. difficile than the Tox A/B II assay (P < 0.0001); however, the difference between PCR and the two-step method was not significant (P = 0.1237). Enhanced sensitivity and rapid turnaround time make the BD GeneOhm Cdiff assay an important advance in the diagnosis of toxigenic C. difficile infection. PMID:19864479

  12. Comparative validation study to demonstrate the equivalence of a minor modification to AOAC Official Method 2005.05 Assurance GDS shiga Toxin Genes (O157) method to the reference culture method: 375 gram sample size.

    Science.gov (United States)

    Feldsine, Philip T; Montgomery-Fullerton, Megan; Roa, Nerie; Kaur, Mandeep; Kerr, David E; Lienau, Andrew H; Jucker, Markus

    2013-01-01

    The Assurance GDS Shiga Toxin Genes (0157), AOAC Official MethodsM 2005.05, has been modified to include a larger sample size of 375 g. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. Ninety samples and controls, representing three foods, were analyzed. Results show no statistically detectable difference between the Assurance GDS Escherichia coli O157:H7 assay and the reference culture methods for the detection of E. coli O157:H7, other than the low level of inoculation for leaf lettuce for which the GDS gave noticeably higher recovery [difference in Probability of Detection between candidate methods (dPODc = +0.45)]. There were also suggestions of moderate differences (dPODc = +0.15 to +0.20) for ground beef and the high level of leaf lettuce, but the study size was too small to detect differences of this size. Results showed that the Assurance GDS Shiga Toxin Genes (0157) method is equivalent to the reference culture methods for the detection of Shiga toxigenic E. coli O157:H7.

  13. Overview of Scorpion Species from China and Their Toxins

    Directory of Open Access Journals (Sweden)

    Zhijian Cao

    2014-02-01

    Full Text Available Scorpions are one of the most ancient groups of terrestrial animals. They have maintained a steady morphology over more than 400 million years of evolution. Their venom arsenals for capturing prey and defending against predators may play a critical role in their ancient and conservative appearance. In the current review, we present the scorpion fauna of China: 53 species covering five families and 12 genera. We also systematically list toxins or genes from Chinese scorpion species, involving eight species covering four families. Furthermore, we review the diverse functions of typical toxins from Chinese scorpion species, involving Na+ channel modulators, K+ channel blockers, antimicrobial peptides and protease inhibitors. Using scorpion species and their toxins from China as an example, we build the bridge between scorpion species and their toxins, which helps us to understand the molecular and functional diversity of scorpion venom arsenal, the dynamic and functional evolution of scorpion toxins, and the potential relationships of scorpion species and their toxins.

  14. Protection against Shiga Toxins

    Directory of Open Access Journals (Sweden)

    Simona Kavaliauskiene

    2017-02-01

    Full Text Available Shiga toxins consist of an A-moiety and five B-moieties able to bind the neutral glycosphingolipid globotriaosylceramide (Gb3 on the cell surface. To intoxicate cells efficiently, the toxin A-moiety has to be cleaved by furin and transported retrogradely to the Golgi apparatus and to the endoplasmic reticulum. The enzymatically active part of the A-moiety is then translocated to the cytosol, where it inhibits protein synthesis and in some cell types induces apoptosis. Protection of cells can be provided either by inhibiting binding of the toxin to cells or by interfering with any of the subsequent steps required for its toxic effect. In this article we provide a brief overview of the interaction of Shiga toxins with cells, describe some compounds and conditions found to protect cells against Shiga toxins, and discuss whether they might also provide protection in animals and humans.

  15. Tetanus toxin light chain expression in Sertoli cells of transgenic mice causes alterations of the actin cytoskeleton and disrupts spermatogenesis

    NARCIS (Netherlands)

    Eisel, Ulrich; Reynolds, Kay; Riddick, Michelle; Zimmer, Anne; Niemann, Heiner; Zimmer, Andreas; Gruss, P.

    Tetanus toxin is a powerful neurotoxin known to inhibit neurotransmitter release. The tetanus toxin light chain is a metalloprotease that cleaves some members of the synaptobrevin gene family with high specificity. Here, we report the expression of a synthetic gene encoding the tetanus toxin light

  16. Microalgal toxin(s): characteristics and importance

    African Journals Online (AJOL)

    Prokaryotic and eukaryotic microalgae produce a wide array of compounds with biological activities. These include antibiotics, algicides, toxins, pharmaceutically active compounds and plant growth regulators. Toxic microalgae, in this sense, are common only among the cyanobacteria and dinoflagellates. The microalgal ...

  17. Oligomerization of Clostridium perfringens epsilon toxin is dependent upon caveolins 1 and 2.

    Directory of Open Access Journals (Sweden)

    Christine M Fennessey

    Full Text Available Evidence from multiple studies suggests that Clostridium perfringens ε-toxin is a pore-forming toxin, assembling into oligomeric complexes in the plasma membrane of sensitive cells. In a previous study, we used gene-trap mutagenesis to identify mammalian factors contributing to toxin activity, including caveolin-2 (CAV2. In this study, we demonstrate the importance of caveolin-2 and its interaction partner, caveolin-1 (CAV1, in ε-toxin-induced cytotoxicity. Using CAV2-specific shRNA in a toxin-sensitive human kidney cell line, ACHN, we confirmed that cells deficient in CAV2 exhibit increased resistance to ε-toxin. Similarly, using CAV1-specific shRNA, we demonstrate that cells deficient in CAV1 also exhibit increased resistance to the toxin. Immunoprecipitation of CAV1 and CAV2 from ε-toxin-treated ACHN cells demonstrated interaction of both CAV1 and -2 with the toxin. Furthermore, blue-native PAGE indicated that the toxin and caveolins were components of a 670 kDa protein complex. Although ε-toxin binding was only slightly perturbed in caveolin-deficient cells, oligomerization of the toxin was dramatically reduced in both CAV1- and CAV2-deficient cells. These results indicate that CAV1 and -2 potentiate ε-toxin induced cytotoxicity by promoting toxin oligomerization - an event which is requisite for pore formation and, by extension, cell death.

  18. Standardisation for C2-Simulation Interoperation

    Science.gov (United States)

    2015-11-01

    using: • National and NATO operational planning and execution tools: NATO ICC, TBMCS, JADOCS and a UAV ground control station ; • Various...an extensive hierarchy of battle space objects such as Organisations, Materiel, Facilities, Features, etc. This taxonomy contains approximately 150...Exploitation of C2‐Sim Interoperability Research to Support the UK Warfighter LtCol Bernardo Neto, Brazilian AF: C2-Simulation Studies in ITA‐GMU

  19. A Topological Model for C2 Organizations

    Science.gov (United States)

    2011-06-01

    Many aspects of C2 are hard to quantify. Topology can be referred as a kind of qualitative math , not the math made of points as usual. Instead, it...like costs, resources and capabilities are important to better define the merit of an organization, understood as the congruence to its mission, and...an adequate mathe - matical construct to capture these higher dimensional relationships. 7. References 16th ICCRTS: Collective C2 in Multinational

  20. Botulinum Toxin Therapy

    Science.gov (United States)

    ... AADA Health System Reform Principles Drug pricing and availability CVS dermatologic formulary restrictions Access to compounded medications ... Botulinum toxin therapy: Overview Also called botulinum rejuvenation Brand names: Botox® Cosmetic, Dysport®, MYOBLOC®, and XEOMIN® When ...

  1. Wallpaper May Breed Toxins

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_166850.html Wallpaper May Breed Toxins: Study Fungus on the walls might ... 2017 FRIDAY, June 23, 2017 (HealthDay News) -- Wallpaper may contribute to "sick building syndrome," a new study ...

  2. Staphylococcus aureus toxins.

    Science.gov (United States)

    Otto, Michael

    2014-02-01

    Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon against bacterial elimination by innate host defense. Furthermore, S. aureus secretes many factors that inhibit the complement cascade or prevent recognition by host defenses. Several further toxins add to this multi-faceted program of S. aureus to evade elimination in the host. This review will give an overview over S. aureus toxins focusing on recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-independent fashions. Published by Elsevier Ltd.

  3. Cationic PAMAM Dendrimers as Pore-Blocking Binary Toxin Inhibitors

    Science.gov (United States)

    2015-01-01

    Dendrimers are unique highly branched macromolecules with numerous groundbreaking biomedical applications under development. Here we identified poly(amido amine) (PAMAM) dendrimers as novel blockers for the pore-forming B components of the binary anthrax toxin (PA63) and Clostridium botulinum C2 toxin (C2IIa). These pores are essential for delivery of the enzymatic A components of the internalized toxins from endosomes into the cytosol of target cells. We demonstrate that at low μM concentrations cationic PAMAM dendrimers block PA63 and C2IIa to inhibit channel-mediated transport of the A components, thereby protecting HeLa and Vero cells from intoxication. By channel reconstitution and high-resolution current recording, we show that the PAMAM dendrimers obstruct transmembrane PA63 and C2IIa pores in planar lipid bilayers at nM concentrations. These findings suggest a new potential role for the PAMAM dendrimers as effective polyvalent channel-blocking inhibitors, which can protect human target cells from intoxication with binary toxins from pathogenic bacteria. PMID:24954629

  4. A regulatory role for Staphylococcus aureus toxin-antitoxin system PemIKSa.

    Science.gov (United States)

    Bukowski, Michal; Lyzen, Robert; Helbin, Weronika M; Bonar, Emilia; Szalewska-Palasz, Agnieszka; Wegrzyn, Grzegorz; Dubin, Grzegorz; Dubin, Adam; Wladyka, Benedykt

    2013-01-01

    Toxin-antitoxin systems were shown to be involved in plasmid maintenance when they were initially discovered, but other roles have been demonstrated since. Here we identify and characterize a novel toxin-antitoxin system (pemIKSa) located on Staphylococcus aureus plasmid pCH91. The toxin (PemKSa) is a sequence-specific endoribonuclease recognizing the tetrad sequence U↓AUU, and the antitoxin (PemISa) inhibits toxin activity by physical interaction. Although the toxin-antitoxin system is responsible for stable plasmid maintenance our data suggest the participation of pemIKSa in global regulation of staphylococcal virulence by alteration of the translation of large pools of genes. We propose a common mechanism of reversible activation of toxin-antitoxin systems based on antitoxin transcript resistance to toxin cleavage. Elucidation of this mechanism is particularly interesting because reversible activation is a prerequisite for the proposed general regulatory role of toxin-antitoxin systems.

  5. Rapid and simple method by combining FTA™ card DNA extraction with two set multiplex PCR for simultaneous detection of non-O157 Shiga toxin-producing Escherichia coli strains and virulence genes in food samples.

    Science.gov (United States)

    Kim, S A; Park, S H; Lee, S I; Ricke, S C

    2017-12-01

    The aim of this research was to optimize two multiplex polymerase chain reaction (PCR) assays that could simultaneously detect six non-O157 Shiga toxin-producing Escherichia coli (STEC) as well as the three virulence genes. We also investigated the potential of combining the FTA™ card-based DNA extraction with the multiplex PCR assays. Two multiplex PCR assays were optimized using six primer pairs for each non-O157 STEC serogroup and three primer pairs for virulence genes respectively. Each STEC strain specific primer pair only amplified 155, 238, 321, 438, 587 and 750 bp product for O26, O45, O103, O111, O121 and O145 respectively. Three virulence genes were successfully multiplexed: 375 bp for eae, 655 bp for stx1 and 477 bp for stx2. When two multiplex PCR assays were validated with ground beef samples, distinctive bands were also successfully produced. Since the two multiplex PCR examined here can be conducted under the same PCR conditions, the six non-O157 STEC and their virulence genes could be concurrently detected with one run on the thermocycler. In addition, all bands clearly appeared to be amplified by FTA card DNA extraction in the multiplex PCR assay from the ground beef sample, suggesting that an FTA card could be a viable sampling approach for rapid and simple DNA extraction to reduce time and labour and therefore may have practical use for the food industry. Two multiplex polymerase chain reaction (PCR) assays were optimized for discrimination of six non-O157 Shiga toxin-producing Escherichia coli (STEC) and identification of their major virulence genes within a single reaction, simultaneously. This study also determined the successful ability of the FTA™ card as an alternative to commercial DNA extraction method for conducting multiplex STEC PCR assays. The FTA™ card combined with multiplex PCR holds promise for the food industry by offering a simple and rapid DNA sample method for reducing time, cost and labour for detection of STEC in

  6. Compact toroid injection into C-2U

    Science.gov (United States)

    Roche, Thomas; Gota, H.; Garate, E.; Asai, T.; Matsumoto, T.; Sekiguchi, J.; Putvinski, S.; Allfrey, I.; Beall, M.; Cordero, M.; Granstedt, E.; Kinley, J.; Morehouse, M.; Sheftman, D.; Valentine, T.; Waggoner, W.; the TAE Team

    2015-11-01

    Sustainment of an advanced neutral beam-driven FRC for a period in excess of 5 ms is the primary goal of the C-2U machine at Tri Alpha Energy. In addition, a criteria for long-term global sustainment of any magnetically confined fusion reactor is particle refueling. To this end, a magnetized coaxial plasma-gun has been developed. Compact toroids (CT) are to be injected perpendicular to the axial magnetic field of C-2U. To simulate this environment, an experimental test-stand has been constructed. A transverse magnetic field of B ~ 1 kG is established (comparable to the C-2U axial field) and CTs are fired across it. As a minimal requirement, the CT must have energy density greater than that of the magnetic field it is to penetrate, i.e., 1/2 ρv2 >=B2 / 2μ0 . This criteria is easily met and indeed the CTs traverse the test-stand field. A preliminary experiment on C-2U shows the CT also capable of penetrating into FRC plasmas and refueling is observed resulting in a 20 - 30% increase in total particle number per single-pulsed CT injection. Results from test-stand and C-2U experiments will be presented.

  7. Functional analysis of the C-II subgroup killer toxin-like chitinases in the filamentous ascomycete Aspergillus nidulans.

    Science.gov (United States)

    Tzelepis, Georgios D; Melin, Petter; Stenlid, Jan; Jensen, Dan Funck; Karlsson, Magnus

    2014-03-01

    Chitinases are hydrolytic enzymes responsible for chitin polymer degradation. Fungal chitinases belong exclusively to glycoside hydrolases family 18 and they are categorized into three phylogenetic groups (A, B and C), which are further divided into subgroups (A-II to A-V, B-I to B-V and C-I to C-II). Subgroup C chitinases display similarity with the α/β-subunit of the zymocin yeast killer toxin produced by Kluyveromyces lactis, suggesting a role of these enzymes in fungal-fungal interactions. In this study, we investigated the regulation and function of 4 Aspergillus nidulans subgroup C-II killer toxin-like chitinases by quantitative PCR and by constructing gene deletion strains. Our results showed that all 4 genes were highly induced during interactions with Botrytis cinerea and Rhizoctonia solani, compared to self-interactions. In addition, chiC2-2 and chiC2-3 were also induced during contact with Fusarium sporotrichoides, while none of these genes were induced during interactions with Phytophthora niederhauserii. In contrast, no difference in expression levels were observed between growth on glucose-rich media compared with media containing colloidal chitin, while all genes were repressed during growth on R. solani cell wall material. Phenotypic analysis of chitinase gene deletion strains revealed that B. cinerea biomass was significantly higher in culture filtrate derived from the ΔchiC2-2 strain compared to biomasses grown in media derived from A. nidulans wild type or the other chitinase gene deletion strains. The analysis also showed that all chitinase gene deletion strains displayed increased biomass production in liquid cultures, and altered response to abiotic stress. In summary, our gene expression data suggest the involvement of A. nidulans subgroup C-II chitinases in fungal-fungal interactions, which is further proven for ChiC2-2. In addition, lacking any of the 4 chitinases influenced the growth of A. nidulans. Copyright © 2013 Elsevier Inc. All

  8. Structural Determinants for Antitoxin Identity and Insulation of Cross Talk between Homologous Toxin-Antitoxin Systems.

    Science.gov (United States)

    Walling, Lauren R; Butler, J Scott

    2016-12-15

    Toxin-antitoxin (TA) systems are ubiquitous in bacteria and archaea, where they play a pivotal role in the establishment and maintenance of dormancy. Under normal growth conditions, the antitoxin neutralizes the toxin. However, under conditions of stress, such as nutrient starvation or antibiotic treatment, cellular proteases degrade the antitoxin, and the toxin functions to arrest bacterial growth. We characterized the specificity determinants of the interactions between VapB antitoxins and VapC toxins from nontypeable Haemophilus influenzae (NTHi) in an effort to gain a better understanding of how antitoxins control toxin activity and bacterial persistence. We studied truncated and full-length antitoxins with single amino acid mutations in the toxin-binding domain. Coexpressing the toxin and antitoxin in Escherichia coli and measuring bacterial growth by dilution plating assayed the ability of the mutant antitoxins to neutralize the toxin. Our results identified two single amino acid residues (W48 and F52) in the C-terminal region of the VapB2 antitoxin necessary for its ability to neutralize its cognate VapC2 toxin. Additionally, we attempted to alter the specificity of VapB1 by making a mutation that would allow it to neutralize its noncognate toxin. A mutation in VapB1 to contain the tryptophan residue identified herein as important in the VapB2-VapC2 interaction resulted in a VapB1 mutant (the T47W mutant) that binds to and neutralizes both its cognate VapC1 and noncognate VapC2 toxins. This represents the first example of a single mutation causing relaxed specificity in a type II antitoxin. Toxin-antitoxin systems are of particular concern in pathogenic organisms, such as nontypeable Haemophilus influenzae, as they can elicit dormancy and persistence, leading to chronic infections and failure of antibiotic treatment. Despite the importance of the TA interaction, the specificity determinants for VapB-VapC complex formation remain uncharacterized. Thus, our

  9. Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium

    OpenAIRE

    Rui Figueiredo; Roderick Card; Carla Nunes; Manal AbuOun; Bagnall, Mary C.; Javier Nunez; Nuno Mendonça; Anjum, Muna F.; Gabriela Jorge da Silva

    2015-01-01

    Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI) and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. T...

  10. Botulinum Toxin (Botox) for Facial Wrinkles

    Science.gov (United States)

    ... Eye Health / Eye Health A-Z Botulinum Toxin (Botox) for Facial Wrinkles Sections Botulinum Toxin (Botox) for ... How Does Botulinum Toxin (Botox) Work? Botulinum Toxin (Botox) for Facial Wrinkles Leer en Español: La toxina ...

  11. Novel Structure and Function of Typhoid Toxin

    Science.gov (United States)

    ... Matters NIH Research Matters July 29, 2013 Novel Structure and Function of Typhoid Toxin Structure of typhoid toxin, showing the 2 A subunits ( ... to cultured cells. The scientists next determined the structure of the typhoid toxin. The toxin was already ...

  12. Oxidative Stress in Shiga Toxin Production by Enterohemorrhagic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Katarzyna Licznerska

    2016-01-01

    Full Text Available Virulence of enterohemorrhagic Escherichia coli (EHEC strains depends on production of Shiga toxins. These toxins are encoded in genomes of lambdoid bacteriophages (Shiga toxin-converting phages, present in EHEC cells as prophages. The genes coding for Shiga toxins are silent in lysogenic bacteria, and prophage induction is necessary for their efficient expression and toxin production. Under laboratory conditions, treatment with UV light or antibiotics interfering with DNA replication are commonly used to induce lambdoid prophages. Since such conditions are unlikely to occur in human intestine, various research groups searched for other factors or agents that might induce Shiga toxin-converting prophages. Among other conditions, it was reported that treatment with H2O2 caused induction of these prophages, though with efficiency significantly lower relative to UV-irradiation or mitomycin C treatment. A molecular mechanism of this phenomenon has been proposed. It appears that the oxidative stress represents natural conditions provoking induction of Shiga toxin-converting prophages as a consequence of H2O2 excretion by either neutrophils in infected humans or protist predators outside human body. Finally, the recently proposed biological role of Shiga toxin production is described in this paper, and the “bacterial altruism” and “Trojan Horse” hypotheses, which are connected to the oxidative stress, are discussed.

  13. Tetanus toxin : primary structure, expression in E. coli, and homology with botulinum toxins

    NARCIS (Netherlands)

    Eisel, Ulrich; Jarausch, Wolfgang; Goretzki, Karin; Henschen, Agnes; Engels, Joachim; Weller, Ulrich; Hudel, Martina; Habermann, Ernst; Niemann, Heiner; Rott, R.

    1986-01-01

    A pool of synthetic oligonucleotides was used to identify the gene encoding tetanus toxin on a 75-kbp plasmid from a toxigenic non-sporulating strain of Clostridium tetani. The nucleotide sequence contained a single open reading frame coding for 1315 amino acids corresponding to a polypeptide with a

  14. The Distributed Cognitive Components of C2

    Science.gov (United States)

    2008-06-01

    force behind most C2 research. Kurt Lewin states that, “There is nothing so useful as a good theory” (1951, p. 169). This link provides the... Lewin , 1951) Lewin , K. (1951). Field theory in social science; selected theoretical papers. D. Cartwright (ed.). New York: Harper & Row. (Liang

  15. Marine Toxins: An Overview

    Science.gov (United States)

    Fusetani, Nobuhiro

    Oceans provide enormous and diverse space for marine life. Invertebrates are conspicuous inhabitants in certain zones such as the intertidal; many are soft-bodied, relatively immobile and lack obvious physical defenses. These animals frequently have evolved chemical defenses against predators and overgrowth by fouling organisms. Marine animals may accumulate and use a variety of toxins from prey organisms and from symbiotic microorganisms for their own purposes. Thus, toxic animals are particularly abundant in the oceans. The toxins vary from small molecules to high molecular weight proteins and display unique chemical and biological features of scientific interest. Many of these substances can serve as useful research tools or molecular models for the design of new drugs and pesticides. This chapter provides an initial survey of these toxins and their salient properties.

  16. Marine and freshwater toxins.

    Science.gov (United States)

    Hungerford, James M

    2006-01-01

    In a very busy and exciting year, 2005 included First Action approval of a much needed official method for paralytic shellfish toxins and multiple international toxin symposia highlighted by groundbreaking research. These are the first-year milestones and activities of the Marine and Freshwater Toxins Task Force and Analytical Community. Inaugurated in 2004 and described in detail in last year's General Referee Report (1) this international toxins group has grown to 150 members from many regions and countries. Perhaps most important they are now making important and global contributions to food safety and to providing alternatives to animal-based assays. Official Method 2005.06 was first approved in late 2004 by the Task Force and subsequently Official First Action in 2005 (2) by the Methods Committee on Natural Toxins and Food Allergens and the Official Methods Board. This nonproprietary method (3) is a precolumn oxidation, liquid chromatographic method that makes good use of fluorescence detection to provide high sensitivity detection of the saxitoxins. It has also proven to be rugged enough for regulatory use and the highest level of validation. As pointed out in the report of method principle investigator and Study Director James Lawrence, approval of 2005.06 now provides the first official alternative to the mouse bioassay after many decades of shellfish monitoring. This past year in April 2005 the group also held their first international conference, "Marine and Freshwater Toxins Analysis: Ist Joint Symposium and AOAC Task Force Meeting," in Baiona, Spain. The 4-day conference consisted of research and stakeholder presentations and symposium-integrated subgroup sessions on ciguatoxins, saxitoxin assays and liquid chromatography (LC) methods for saxitoxins and domoic acids, okadaiates and azaspiracids, and yessotoxins. Many of these subgroups were recently formed in 2005 and are working towards their goals of producing officially validated analytical methods

  17. New C2 synchondrosal fracture classification system

    Energy Technology Data Exchange (ETDEWEB)

    Rusin, Jerome A.; Ruess, Lynne [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States); The Ohio State University College of Medicine and Public Health, Columbus, OH (United States); Daulton, Robert S. [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States)

    2015-06-15

    Excessive cervical flexion-extension accompanying mild to severe impact injuries can lead to C2 synchondrosal fractures in young children. To characterize and classify C2 synchondrosal fracture patterns. We retrospectively reviewed imaging and medical records of children who were treated for cervical spine fractures at our institution between 1995 and 2014. We reviewed all fractures involving the five central C2 synchondroses with regard to patient demographics, mechanism of injury, fracture pattern, associated fractures and other injuries, treatment plans and outcome. Fourteen children had fractures involving the central C2 synchondroses. There were nine boys and five girls, all younger than 6 years. We found four distinct fracture patterns. Eleven complete fractures were further divided into four subtypes (a, b, c and d) based on degree of anterior displacement of the odontoid segment and presence of distraction. Nine of these 11 children had fractures through both odontoneural synchondroses and the odontocentral synchondrosis; one had fractures involving both neurocentral synchondroses and the odontoneural synchondrosis; one had fractures through bilateral odontoneural and bilateral neurocentral synchondroses. Three children had incomplete fractures, defined as a fracture through a single odontoneural synchondrosis with or without partial extension into either the odontocentral or the adjacent neurocentral synchondroses. All complete fractures were displaced or angulated. Four had associated spinal cord injury, including two contusions (subtype c fractures) and two fatal transections (subtype d fractures). Most children were treated with primary halo stabilization. Subtype c fractures required surgical fixation. We describe four patterns of central C2 synchondrosal fractures, including two unique patterns that have not been reported. We propose a classification system to distinguish these fractures and aid in treatment planning. (orig.)

  18. Toxin Profile, Biofilm Formation, and Molecular Characterization of Emetic Toxin-Producing Bacillus cereus Group Isolates from Human Stools.

    Science.gov (United States)

    Oh, Su Kyung; Chang, Hyun-Joo; Choi, Sung-Wook; Ok, Gyeongsik; Lee, Nari

    2015-11-01

    Emetic toxin-producing Bacillus cereus group species are an important problem, because the staple food for Korean is grains such as rice. In this study, we determined the prevalence (24 of 129 isolates) of emetic B. cereus in 36,745 stool samples from sporadic food-poisoning cases in Korea between 2007 and 2008. The toxin gene profile, toxin production, and biofilm-forming ability of the emetic B. cereus isolates were investigated. Repetitive element sequence polymorphism polymerase chain reaction fingerprints (rep-PCR) were also used to assess the intraspecific biodiversity of these isolates. Emetic B. cereus was present in 0.07% of the sporadic food-poisoning cases. The 24 emetic isolates identified all carried the nheABC and entFM genes and produced NHE enterotoxin. However, they did not have hemolysin BL toxin or related genes. A relationship between biofilm formation and toxin production was not observed in this study. The rep-PCR fingerprints of the B. cereus isolates were not influenced by the presence of toxin genes, or biofilm-forming ability. The rep-PCR assay discriminated emetic B. cereus isolates from nonemetic isolates, even if this assay did not perfectly discriminate these isolates. Further study on emetic isolates possessing a high degree of diversity may be necessary to evaluate the performance of the subtyping assay to discriminate emetic and nonemetic B. cereus isolates and could provide a more accurate indication of the risk from B. cereus strains.

  19. Secondary metabolite toxins and nutrition of plant pathogenic fungi.

    Science.gov (United States)

    Howlett, Barbara J

    2006-08-01

    Fungal pathogens derive nutrition from the plants they invade. Some fungi can subvert plant defence responses such as programmed cell death to provide nutrition for their growth and colonisation. Secondary metabolite toxins produced by fungi often play a role in triggering these responses. Knowledge of the biosynthesis of these toxins, and the availability of fungal genome sequences and gene disruption techniques, allows the development of tools for experiments aimed at discovering the role of such toxins in triggering plant cell death and plant disease.

  20. The transcriptional regulator c2h2 acceleratesmushroom formation in Agaricus bisporus

    NARCIS (Netherlands)

    Pelkmans, Jordi F.; Vos, A.M.; Scholtmeijer, Karin; Hendrix, Ed; Baars, Johan J.P.; Gehrmann, T.; Reinders, M.J.T.; Lugones, Luis G.; Wösten, Han A.B.

    2016-01-01

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom

  1. The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus

    NARCIS (Netherlands)

    Pelkmans, J.F.; Vos, A.M.; Scholtmeijer, K; Hendrix, Eddy; Baars, Johan J; Gehrmann, Thies; Reinders, Marcel J; Lugones, L.G.; Wösten, HAB

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom

  2. The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus

    NARCIS (Netherlands)

    Pelkmans, Jordi F.; Vos, Aurin M.; Scholtmeijer, Karin; Hendrix, Ed; Baars, Johan J.P.; Gehrmann, Thies; Reinders, Marcel J.T.; Lugones, Luis G.; Wösten, Han A.B.

    2016-01-01

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button

  3. [Toxins as a biological weapon].

    Science.gov (United States)

    Płusa, Tadeusz

    2015-09-01

    The criteria for recognizing a chemical compound for the toxin are vague and gave it the possibility of inclusion in this group a number of biological agents. Toxins list is extensive, but the interest is focused on bacterial toxins, poisons derived from snake venoms, algae and plant proteins, and small molecules. Particular attention is focused on the so-called "sea" toxins, which include tetrodotoxin, brevetoxin and saxitoxin. This indicates the search for a new hitherto unknown potential bioterrorist threats. © 2015 MEDPRESS.

  4. Command and Control (C2) Agility (Agilite du commandement et du controle (C2))

    Science.gov (United States)

    2014-10-01

    Space Mapping Guide, an Enablers of Agility Checklist , and C2 Maneuver Guidelines and Procedures. • Develop systems and decision aids that support...called spider charts. The “arms” of the chart correspond to the same dimensions as the cube model for C2 maturity: distribution of decision rights

  5. A hemolytic-uremic syndrome-associated strain O113:H21 Shiga toxin-producing Escherichia coli specifically expresses a transcriptional module containing dicA and is related to gene network dysregulation in Caco-2 cells.

    Science.gov (United States)

    Bando, Silvia Yumi; Iamashita, Priscila; Guth, Beatriz E; Dos Santos, Luis F; Fujita, André; Abe, Cecilia M; Ferreira, Leandro R; Moreira-Filho, Carlos Alberto

    2017-01-01

    Shiga toxin-producing (Stx) Escherichia coli (STEC) O113:H21 strains are associated with human diarrhea and some of these strains may cause hemolytic uremic syndrome (HUS). The molecular mechanism underlying this capacity and the differential host cell response to HUS-causing strains are not yet completely understood. In Brazil O113:H21 strains are commonly found in cattle but, so far, were not isolated from HUS patients. Here we conducted comparative gene co-expression network (GCN) analyses of two O113:H21 STEC strains: EH41, reference strain, isolated from HUS patient in Australia, and Ec472/01, isolated from cattle feces in Brazil. These strains were cultured in fresh or in Caco-2 cell conditioned media. GCN analyses were also accomplished for cultured Caco-2 cells exposed to EH41 or Ec472/01. Differential transcriptome profiles for EH41 and Ec472/01 were not significantly changed by exposure to fresh or Caco-2 conditioned media. Conversely, global gene expression comparison of both strains cultured in conditioned medium revealed a gene set exclusively expressed in EH41, which includes the dicA putative virulence factor regulator. Network analysis showed that this set of genes constitutes an EH41 specific transcriptional module. PCR analysis in Ec472/01 and in other 10 Brazilian cattle-isolated STEC strains revealed absence of dicA in all these strains. The GCNs of Caco-2 cells exposed to EH41 or to Ec472/01 presented a major transcriptional module containing many hubs related to inflammatory response that was not found in the GCN of control cells. Moreover, EH41 seems to cause gene network dysregulation in Caco-2 as evidenced by the large number of genes with high positive and negative covariance interactions. EH41 grows slowly than Ec472/01 when cultured in Caco-2 conditioned medium and fitness-related genes are hypoexpressed in that strain. Therefore, EH41 virulence may be derived from its capacity for dysregulating enterocyte genome functioning and its

  6. NATO NEC C2 Maturity Model

    Science.gov (United States)

    2010-02-01

    goes beyond awareness and includes perceptions of a larger picture including cause and effect as well as temporal dynamics. See Understanding...Germany ( Saxony ) dur- ing 2002. It required an endeavour composed of local, state, and national organisations as well as a number of NGOs. 118...Conflicted C2 approach. In other words, the endeavour lacked a common picture of what had happened and what needed to be done which strongly impacted

  7. Hereditary deficiency of the second component of complement (C2) in man: correlation of C2 haemolytic activity with immunochemical measurements of C2 protein

    Science.gov (United States)

    Ruddy, S.; Klemperer, M. R.; Rosen, F. S.; Austen, K. F.; Kumate, J.

    1970-01-01

    Measurements of the nine components of complement in the serums of 16 members of a kindred have established the diagnosis of hereditary deficiency of the second component of complement (C2). The autosomal recessive mode of inheritance resembles that of previously described families with C2 deficiency. Both C2 activity determinations with a stoichiometric haemolytic assay and C2 protein measurements with electroimmunodiffusion against antibody monospecific for C2 detect the heterozygous deficient state. Antigenic analysis, in vitro reconstitution experiments, and the constant ratio of C2 function to C2 protein indicate that the C2 synthesized by heterozygotes is indistinguishable from normal human C2. Studies of neonatal homozygous deficient serum and maternal heterozygous deficient serum show that transplacental passage of C2 does not occur. C2 deficiency in this family is not associated with clinical defects in host resistance. ImagesFIG. 3 PMID:4987909

  8. Toxins Best Paper Award 2015

    Directory of Open Access Journals (Sweden)

    Vernon L. Tesh

    2015-03-01

    Full Text Available In order to recognize outstanding papers related to biotoxins and toxinology that have been published in Toxins, the Editorial Board established an annual “Toxins Best Paper Award”. We are pleased to announce the first “Toxins Best Paper Award” for 2015. Nominations were selected by the Editorial Board members, with all papers published in 2011 eligible for consideration. Reviews and original research articles were evaluated separately. Following review and voting by the Toxins Best Paper Award Committee, the following three papers have won Toxins Best Paper Awards for 2015:[...

  9. Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium.

    Directory of Open Access Journals (Sweden)

    Rui Figueiredo

    Full Text Available Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. Typhimurium in two clusters. Atypical microarray results lead to whole genome sequencing (WGS of S. Infantis Sal147, which identified deletion of thirty-eight SPI-1 genes. Sal147 was unable to invade HeLa cells and showed reduced mortality in Galleria mellonella infection model, in comparison to a SPI-1 harbouring S. Infantis. Microarray and WGS of S. Typhimurium Sal199, established for the first time in S. Typhimurium presence of cdtB and other Typhi-related genes. Characterization of Sal199 showed cdtB genes were upstream of transposase IS911, and co-expressed with other Typhi-related genes. Cell cycle arrest, cytoplasmic distension, and nuclear enlargement were detected in HeLa cells infected by Sal199, but not with S. Typhimurium LT2. Increased mortality of Galleria was detected on infection with Sal199 compared to LT2. Thus, Salmonella isolates were rapidly characterized using a high through-put microarray; helping to identify unusual virulence features which were corroborated by further characterisation. This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans. Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

  10. Virulence Characterization of Salmonella enterica by a New Microarray: Detection and Evaluation of the Cytolethal Distending Toxin Gene Activity in the Unusual Host S. Typhimurium.

    Science.gov (United States)

    Figueiredo, Rui; Card, Roderick; Nunes, Carla; AbuOun, Manal; Bagnall, Mary C; Nunez, Javier; Mendonça, Nuno; Anjum, Muna F; da Silva, Gabriela Jorge

    2015-01-01

    Salmonella enterica is a zoonotic foodborne pathogen that causes acute gastroenteritis in humans. We assessed the virulence potential of one-hundred and six Salmonella strains isolated from food animals and products. A high through-put virulence genes microarray demonstrated Salmonella Pathogenicity Islands (SPI) and adherence genes were highly conserved, while prophages and virulence plasmid genes were variably present. Isolates were grouped by serotype, and virulence plasmids separated S. Typhimurium in two clusters. Atypical microarray results lead to whole genome sequencing (WGS) of S. Infantis Sal147, which identified deletion of thirty-eight SPI-1 genes. Sal147 was unable to invade HeLa cells and showed reduced mortality in Galleria mellonella infection model, in comparison to a SPI-1 harbouring S. Infantis. Microarray and WGS of S. Typhimurium Sal199, established for the first time in S. Typhimurium presence of cdtB and other Typhi-related genes. Characterization of Sal199 showed cdtB genes were upstream of transposase IS911, and co-expressed with other Typhi-related genes. Cell cycle arrest, cytoplasmic distension, and nuclear enlargement were detected in HeLa cells infected by Sal199, but not with S. Typhimurium LT2. Increased mortality of Galleria was detected on infection with Sal199 compared to LT2. Thus, Salmonella isolates were rapidly characterized using a high through-put microarray; helping to identify unusual virulence features which were corroborated by further characterisation. This work demonstrates that the use of suitable screening methods for Salmonella virulence can help assess the potential risk associated with certain Salmonella to humans. Incorporation of such methodology into surveillance could help reduce the risk of emergence of epidemic Salmonella strains.

  11. Autoproteolytic Activation of Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Aimee Shen

    2010-05-01

    Full Text Available Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD in Multifunctional Autoprocessing RTX-like (MARTX and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP6, which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins.

  12. N2C2M2 Experimentation and Validation: Understanding Its C2 Approaches and Implications

    Science.gov (United States)

    2010-06-01

    the organization and execution of the experiments, specifically, Col. Fernando Freire , LtCol. António Flambó, LtCol. José Martins, LtCol. Paulo ...of ELICIT Experimental Data. Paper presented at the 13th ICCRTS, Seattle, USA, 2008. [13.] Manso, Marco, and Paulo Nunes. ELICIT and the Future C2...detailed mapping between C2 CRM variables and ELICIT refer to: MANSO, Marco, and Paulo NUNES. ELICIT and the Future C2: Theoretical Foundations for the

  13. Tailored Microarray Platform for the Detection of Marine Toxins

    NARCIS (Netherlands)

    Bovee, T.F.H.; Hendriksen, P.J.M.; Portier, L.; Wang, S.; Elliott, C.T.; Egmond, van H.P.; Nielen, M.W.F.; Peijnenburg, A.A.C.M.; Hoogenboom, L.A.P.

    2011-01-01

    Currently, there are no fast in vitro broad spectrum screening bioassays for the detection of marine toxins. The aim of this study was to develop such an assay. In gene expression profiling experiments 17 marker genes were provisionally selected that were differentially regulated in human intestinal

  14. TcdC does not significantly repress toxin expression in Clostridium difficile 630ΔErm.

    Directory of Open Access Journals (Sweden)

    Dennis Bakker

    Full Text Available In the past decade, Clostridium difficile has emerged as an important gut pathogen. Symptoms of C. difficile infection range from mild diarrhea to pseudomembranous colitis, sometimes resulting in colectomy or death. The main virulence factors of C. difficile are toxin A and toxin B. Besides the genes encoding these toxins (tcdA and tcdB, the pathogenicity locus (PaLoc also contains genes encoding a sigma factor (tcdR and a putative anti-sigma factor (tcdC. The important role of TcdR as a sigma factor for toxin expression is undisputed, whereas the role of TcdC as an anti-sigma factor, inhibiting toxin expression, is currently the subject of debate. To clarify the role of TcdC in toxin expression, we generated an isogenic ClosTron-based mutant of tcdC in Clostridium difficile strain 630Δ Erm (CT::tcdC and determined the transcription levels of the PaLoc genes and the expression levels of the toxins in the wild type strain and the tcdC mutant strain. We found only minor differences in transcription levels of the PaLoc genes between the wild type and CT::tcdC strains and total toxin levels did not significantly differ either. These results suggest that in C. difficile 630Δerm TcdC is not a major regulator of toxin expression under the conditions tested.

  15. The Rest of the C2 Iceberg

    Science.gov (United States)

    2014-08-01

    exercise.2 As one would expect, however, there is much, much more to the C2 story in terms of who created the plan and whether it will contribute to...rigor to the air tasking process, and significant risks may arise if its contributions —and the reasons they were introduced in the first place—are not...http://www.dodccrp.org/. 28. Using three domains to approximate reality has many historical antecedents, includ- ing versions by Plato through J. F. C

  16. Many roads to resistance: how invertebrates adapt to Bt toxins.

    Science.gov (United States)

    Griffitts, Joel S; Aroian, Raffi V

    2005-06-01

    The Cry family of Bacillus thuringiensis insecticidal and nematicidal proteins constitutes a valuable source of environmentally benign compounds for the control of insect pests and disease agents. An understanding of Cry toxin resistance at a molecular level will be critical to the long-term utility of this technology; it may also shed light on basic mechanisms used by other bacterial toxins that target specific organisms or cell types. Selection and cross-resistance studies have confirmed that genetic adaptation can elicit varying patterns of Cry toxin resistance, which has been associated with deficient protoxin activation by host proteases, and defective Cry toxin-binding cell surface molecules, such as cadherins, aminopeptidases and glycolipids. Recent work also suggests Cry toxin resistance may be induced in invertebrates as an active immune response. The use of model invertebrates, such as Caenorhabditis elegans and Drosophila melanogaster, as well as advances in insect genomics, are likely to accelerate efforts to clone Cry toxin resistance genes and come to a detailed and broad understanding of Cry toxin resistance.

  17. Overview of C-2U FRC Experimental Program and Plans for C-2W

    Science.gov (United States)

    Gota, H.; Binderbauer, M. W.; Tajima, T.; Putvinski, S.; Tuszewski, M.; Dettrick, S.; Korepanov, S.; Smirnov, A.; Thompson, M. C.; Yang, X.; Cappello, M.; Ivanov, A. A.; TAE Team

    2016-10-01

    Tri Alpha Energy's experimental program has been focused on a demonstration of reliable field-reversed configuration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world's largest compact-toroid experimental devices, C-2 and C-2U, have successfully produced a well-stabilized, sustainable FRC plasma state with NB injection (input power, PNB 10 + MW; 15 keV hydrogen) and end-on coaxial plasma guns. Remarkable improvements in confinement and stability of FRC plasmas have led to further improved fast-ion build up; thereby, an advanced beam-driven FRC state has been produced and sustained for up to 5 + ms (longer than all characteristic system time scales), only limited by hardware and electric supply constraints such as NB and plasma-gun power supplies. To further improve the FRC performance the C-2U device is being replaced by C-2W featuring higher injected NB power, longer pulse duration as well as enhanced edge-biasing systems and substantially upgraded divertors. Main C-2U experimental results and key features of C-2W will be presented. Tri Alpha Energy, Inc.

  18. The Influence of Low Doses of Zearalenone and T-2 Toxin on Calcitonin Gene Related Peptide-Like Immunoreactive (CGRP-LI Neurons in the ENS of the Porcine Descending Colon

    Directory of Open Access Journals (Sweden)

    Krystyna Makowska

    2017-03-01

    Full Text Available The enteric nervous system (ENS can undergo adaptive and reparative changes in response to physiological and pathological stimuli. These manifest primarily as alterations in the levels of active substances expressed by the enteric neuron. While it is known that mycotoxins can affect the function of the central and peripheral nervous systems, knowledge about their influence on the ENS is limited. Therefore, the aim of the present study was to investigate the influence of low doses of zearalenone (ZEN and T-2 toxin on calcitonin gene related peptide-like immunoreactive (CGRP-LI neurons in the ENS of the porcine descending colon using a double immunofluorescence technique. Both mycotoxins led to an increase in the percentage of CGRP-LI neurons in all types of enteric plexuses and changed the degree of co-localization of CGRP with other neuronal active substances, such as substance P, galanin, nitric oxide synthase, and cocaine- and amphetamine-regulated transcript peptide. The obtained results demonstrate that even low doses of ZEN and T-2 can affect living organisms and cause changes in the neurochemical profile of enteric neurons.

  19. C-2W Magnetic Measurement Suite

    Science.gov (United States)

    Roche, T.; Thompson, M. C.; Griswold, M.; Knapp, K.; Koop, B.; Ottaviano, A.; Tobin, M.; TAE, Tri Alpha Energy, Inc. Team

    2017-10-01

    Commissioning and early operations are underway on C-2W, Tri Alpha Energy's new FRC experiment. The increased complexity level of this machine requires an equally enhanced diagnostic capability. A fundamental component of any magnetically confined fusion experiment is a firm understanding of the magnetic field itself. C-2W is outfitted with over 700 magnetic field probes, 550 internal and 150 external. Innovative in-vacuum annular flux loop / B-dot combination probes will provide information about plasma shape, size, pressure, energy, total temperature, and trapped flux when coupled with establish theoretical interpretations. The massive Mirnov array, consisting of eight rings of eight 3D probes, will provide detailed information about plasma motion, stability, and MHD modal content with the aid of singular value decomposition (SVD) analysis. Internal Rogowski probes will detect the presence of axial currents flowing in the plasma jet in multiple axial locations. Initial data from this array of diagnostics will be presented along with some interpretation and discussion of the analysis techniques used.

  20. Characterization of Hemagglutinin Negative Botulinum Progenitor Toxins

    Directory of Open Access Journals (Sweden)

    Suzanne R. Kalb

    2017-06-01

    Full Text Available Botulism is a disease involving intoxication with botulinum neurotoxins (BoNTs, toxic proteins produced by Clostridium botulinum and other clostridia. The 150 kDa neurotoxin is produced in conjunction with other proteins to form the botulinum progenitor toxin complex (PTC, alternating in size from 300 kDa to 500 kDa. These progenitor complexes can be classified into hemagglutinin positive or hemagglutinin negative, depending on the ability of some of the neurotoxin-associated proteins (NAPs to cause hemagglutination. The hemagglutinin positive progenitor toxin complex consists of BoNT, nontoxic non-hemagglutinin (NTNH, and three hemagglutinin proteins; HA-70, HA-33, and HA-17. Hemagglutinin negative progenitor toxin complexes contain BoNT and NTNH as the minimally functional PTC (M-PTC, but not the three hemagglutinin proteins. Interestingly, the genome of hemagglutinin negative progenitor toxin complexes comprises open reading frames (orfs which encode for three proteins, but the existence of these proteins has not yet been extensively demonstrated. In this work, we demonstrate that these three proteins exist and form part of the PTC for hemagglutinin negative complexes. Several hemagglutinin negative strains producing BoNT/A, /E, and /F were found to contain the three open reading frame proteins. Additionally, several BoNT/A-containing bivalent strains were examined, and NAPs from both genes, including the open reading frame proteins, were associated with BoNT/A. The open reading frame encoded proteins are more easily removed from the botulinum complex than the hemagglutinin proteins, but are present in several BoNT/A and /F toxin preparations. These are not easily removed from the BoNT/E complex, however, and are present even in commercially-available purified BoNT/E complex.

  1. CD44 Promotes intoxication by the clostridial iota-family toxins.

    Directory of Open Access Journals (Sweden)

    Darran J Wigelsworth

    Full Text Available Various pathogenic clostridia produce binary protein toxins associated with enteric diseases of humans and animals. Separate binding/translocation (B components bind to a protein receptor on the cell surface, assemble with enzymatic (A component(s, and mediate endocytosis of the toxin complex. Ultimately there is translocation of A component(s from acidified endosomes into the cytosol, leading to destruction of the actin cytoskeleton. Our results revealed that CD44, a multifunctional surface protein of mammalian cells, facilitates intoxication by the iota family of clostridial binary toxins. Specific antibody against CD44 inhibited cytotoxicity of the prototypical Clostridium perfringens iota toxin. Versus CD44(+ melanoma cells, those lacking CD44 bound less toxin and were dose-dependently resistant to C. perfringens iota, as well as Clostridium difficile and Clostridium spiroforme iota-like, toxins. Purified CD44 specifically interacted in vitro with iota and iota-like, but not related Clostridium botulinum C2, toxins. Furthermore, CD44 knockout mice were resistant to iota toxin lethality. Collective data reveal an important role for CD44 during intoxication by a family of clostridial binary toxins.

  2. Toxins of Amanita phalloides.

    Science.gov (United States)

    Vetter, J

    1998-01-01

    The most poisonous mushroom toxins are produced by Amanita phalloides (death cap). The occurrence and chemistry of three groups of toxins (amatoxins, phallotoxins and virotoxins) are summarized. The concentration and distribution of toxins in certain species are variable, with the young fruit body containing lower, and the well-developed fungus higher concentrations, but there is a high variability among specimens collected in the same region. Regarding phallotoxins, the volva (the ring) is the most poisonous. The most important biochemical effect of amatoxins is the inhibition of RNA polymerases (especially polymerase II). This interaction leads to a tight complex and the inhibition is of a non-competitive type. Non-mammalian polymerases show little sensitivity to amanitins. The amatoxins cause necrosis of the liver, also partly in the kidney, with the cellular changes causing the fragmentation and segregation of all nuclear components. Various groups of somatic cells of emanation resistance have been isolated, including from a mutant of Drosophila melanogaster. The phallotoxins stimulate the polymerization of G-actin and stabilize the F-actin filaments. The interaction of phallotoxins occurs via the small, 15-membered ring, on the left side of the spatial formula. The symptoms of human poisoning and the changes in toxin concentrations in different organs are summarized. Conventional therapy includes: (1) stabilization of patient's condition with the correction of hypoglycaemia and electrolytes; (2) decontamination; and (3) chemotherapy with different compounds. Finally, certain antagonists and protective compounds are reviewed, bearing in mind that today these have more of a theoretical than a practical role.

  3. Inhibitory effect of eugenol on aflatoxin B1 production in Aspergillus parasiticus by downregulating the expression of major genes in the toxin biosynthetic pathway.

    Science.gov (United States)

    Jahanshiri, Zahra; Shams-Ghahfarokhi, Masoomeh; Allameh, Abdolamir; Razzaghi-Abyaneh, Mehdi

    2015-07-01

    Aflatoxin contamination of grains and agro-products is a serious food safety issue and a significant economic concern worldwide. In the present study, the effects of eugenol on Aspergillus parasiticus growth and aflatoxin production were studied in relation to the expression of some essential genes involved in aflatoxin biosynthetic pathway. The fungus was cultured in presence of serial two-fold concentrations of eugenol (15.62-500 μg mL(-1)) for 3 days at 28 °C. Mycelia dry weight was determined as an index of fungal growth, while aflatoxin production was assessed by high performance liquid chromatography. The expression of aflatoxin biosynthetic genes including ver-1, nor-1, pksA, omtA and aflR were evaluated by real-time PCR. Eugenol strongly inhibited A. parasiticus growth in the range of 19.16-95.83 % in a dose-dependent manner. Aflatoxin B1 production was also inhibited by the compound in the range of 15.07-98.0 %. The expressions of ver-1, nor-1, pksA, omtA and aflR genes were significantly suppressed by eugenol at concentrations of 62.5 and 125 μg mL(-1). These results indicate that eugenol may be considered as a good candidate to control toxigenic fungal growth and the subsequent contamination of food, feed and agricultural commodities by carcinogenic aflatoxins.

  4. Isolation, Characterization and Antibiotic Resistance of Shiga Toxin-Producing Escherichia coli in Hamburger and Evolution of Virulence Genes stx1, stx2, eaeA and hly by Multiplex PCR

    Directory of Open Access Journals (Sweden)

    Mohammad Kargar

    2013-09-01

    Full Text Available Background & Objectives: Shiga toxin-producing Escherichia coli (STEC O157:H7 have emerged as pathogens that can cause food-borne infections and severe and potentially fatal illnesses in humans. E.coli O157:H7 colonizes the digestive tract of cattle and is transmitted to humans by food and water. The objectives of this study were to characterize the prevalence of E.coli O157:H7 isolates in hamburger in Shiraz and to test their antimicrobial sensitivity. Material & Methods: In this research, 428 samples of hamburger were collected from 7 main factories of meat products and enriched in TSB with novobiocin medium at 37ºC. Fermentation of sorbitol and lactose and activities of β- glucuronidase of separated bacteria were examined by using the SMAC and VRBA media and CHROMagar medium. Then isolation of E.coli O157:H7 was confirmed with the use of specific antisera; and with the multiplex PCR method, the presence of E.coli O157:H7 virulence genes – including stx1, stx2, eaeA, and hly – was analyzed. Finally, antibiotic resistance strains were tested with disk diffusion methods. Results: Out of all the examined samples, 264 (61.68% sorbitol-negative bacteria were separated in the CT-SMAC medium. After evaluation with specific antisera, the rate of the recognition of E.coli O157:H7 was 5 (1.17%. The stx1 and eaeA genes were diagnosed in 2 (0.47% cases of these samples. All the isolated bacteria were resistant to penicillin, clindamycin, and erythromycin antibiotics.Conclusion: The presence of STEC in animal products suggests that they may be a potential hazard for human health. A regular monitoring of STEC O157, mainly in hamburger, should be performed to prevent a possible consumer health threat.

  5. Removal of Paralytic Shellfish Toxins by Probiotic Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Mari Vasama

    2014-07-01

    Full Text Available Paralytic shellfish toxins (PSTs are non-protein neurotoxins produced by saltwater dinoflagellates and freshwater cyanobacteria. The ability of Lactobacillus rhamnosus strains GG and LC-705 (in viable and non-viable forms to remove PSTs (saxitoxin (STX, neosaxitoxin (neoSTX, gonyautoxins 2 and 3 (GTX2/3, C-toxins 1 and 2 (C1/2 from neutral and acidic solution (pH 7.3 and 2 was examined using HPLC. Binding decreased in the order of STX ~ neoSTX > C2 > GTX3 > GTX2 > C1. Removal of STX and neoSTX (77%–97.2% was significantly greater than removal of GTX3 and C2 (33.3%–49.7%. There were no significant differences in toxin removal capacity between viable and non-viable forms of lactobacilli, which suggested that binding rather than metabolism is the mechanism of the removal of toxins. In general, binding was not affected by the presence of other organic molecules in solution. Importantly, this is the first study to demonstrate the ability of specific probiotic lactic bacteria to remove PSTs, particularly the most toxic PST-STX, from solution. Further, these results warrant thorough screening and assessment of safe and beneficial microbes for their usefulness in the seafood and water industries and their effectiveness in vivo.

  6. Detection of the genes encoding the toxin CDT, and research factors which influence the production of hemolysin in Campylobacter jejuni from poultry products

    OpenAIRE

    Trindade, Michele Martins; Perdoncini,Gustavo; Sierra Arguello, Yuli Melisa; Lovato, Maristela; Borsoi,Anderlise; Nascimento, Vladimir Pinheiro do

    2015-01-01

    Resumo: Membros termofílicos do gênero Campylobacter são reconhecidos como importantes enteropatógenos para o ser humano e animais. A grande diversidade ecológica destes micro-organismos em diferentes habitats tais como água, animais e alimentos predispõem ao aparecimento de novos fatores de virulência. Este trabalho teve por objetivo detectar os genes codificantes da Toxina Distensiva Citoletal (CDT) por meio da técnica de PCR, pesquisar a atividade de hemolisinas e a influência de soluções ...

  7. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

    Science.gov (United States)

    Gaucher, Marie-Lou; Perron, Gabriel G.; Arsenault, Julie; Letellier, Ann; Boulianne, Martine; Quessy, Sylvain

    2017-01-01

    Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time. PMID:28567032

  8. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

    Directory of Open Access Journals (Sweden)

    Marie-Lou Gaucher

    2017-05-01

    Full Text Available Extensive use of antibiotic growth promoters (AGPs in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.

  9. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population.

    Science.gov (United States)

    Gaucher, Marie-Lou; Perron, Gabriel G; Arsenault, Julie; Letellier, Ann; Boulianne, Martine; Quessy, Sylvain

    2017-01-01

    Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.

  10. Nondissociative low energy electron attachment to C2Cl4:C2Cl4- ion lifetime

    Science.gov (United States)

    Suess, L.; Parthasarathy, R.; Dunning, F. B.

    2003-04-01

    The lifetimes of long-lived parent anions formed by nondissociative electron attachment to C2Cl4 are investigated using Rydberg atom techniques. The ions are created through electron transfer in collisions with K(np) Rydberg atoms and their lifetimes are measured using both time-of-flight techniques and a permanent magnet Penning trap designed specifically for heavy ion storage. The data show that low-energy electron attachment to C2Cl4 leads to the formation of C2Cl4- ions with a broad range of lifetimes extending from ˜3 to ˜130 μs, which is attributed to capture by molecules in different initial vibrational states.

  11. Genomic characterisation of the toxin Amm VIII from the scorpion Androctonus mauretanicus mauretanicus.

    Science.gov (United States)

    Alami, Meriem; Céard, Brigitte; Legros, Christian; Bougis, Pierre E; Martin-Eauclaire, Marie-France

    2006-04-01

    The genomic DNA sequence encoding the scorpion toxin Amm VIII was amplified from genomic DNA of the scorpion Androctonus mauretanicus mauretanicus from Morocco, subcloned and sequenced. An intron, with a high A+T content (73.5%), split a Gly codon at the end of the precursor signal peptide and the consensus GT/AG splice junction was identified in the Amm VIII gene. This intron of only 166 bp is the smallest intron described so far for a long-chain scorpion toxin gene. In addition, this study led to the identification of three new toxin-related genes. From the deduced amino acid sequences of the encoded precursor proteins, we found that the mature putative toxins were highly similar to the scorpion toxins Leiurus quinquestriatus quinquestriatus IV and Odonthobuthus doriae 1.

  12. Clostridium Perfringens Toxins Involved in Mammalian Veterinary Diseases

    Science.gov (United States)

    Uzal, F. A.; Vidal, J. E.; McClane, B. A.; Gurjar, A. A.

    2013-01-01

    Clostridium perfringens is a gram-positive anaerobic rod that is classified into 5 toxinotypes (A, B, C, D, and E) according to the production of 4 major toxins, namely alpha (CPA), beta (CPB), epsilon (ETX) and iota (ITX). However, this microorganism can produce up to 16 toxins in various combinations, including lethal toxins such as perfringolysin O (PFO), enterotoxin (CPE), and beta2 toxin (CPB2). Most diseases caused by this microorganism are mediated by one or more of these toxins. The role of CPA in intestinal disease of mammals is controversial and poorly documented, but there is no doubt that this toxin is essential in the production of gas gangrene of humans and several animal species. CPB produced by C. perfringens types B and C is responsible for necrotizing enteritis and enterotoxemia mainly in neonatal individuals of several animal species. ETX produced by C. perfringens type D is responsible for clinical signs and lesions of enterotoxemia, a predominantly neurological disease of sheep and goats. The role of ITX in disease of animals is poorly understood, although it is usually assumed that the pathogenesis of intestinal diseases produced by C. perfringens type E is mediated by this toxin. CPB2, a necrotizing and lethal toxin that can be produced by all types of C. perfringens, has been blamed for disease in many animal species, but little information is currently available to sustain or rule out this claim. CPE is an important virulence factor for C. perfringens type A gastrointestinal disease in humans and dogs; however, the data implicating CPE in other animal diseases remains ambiguous. PFO does not seem to play a direct role as the main virulence factor for animal diseases, but it may have a synergistic role with CPA-mediated gangrene and ETX-mediated enterotoxemia. The recent improvement of animal models for C. perfringens infection and the use of toxin gene knock-out mutants have demonstrated the specific pathogenic role of several toxins of C

  13. The DinJ/RelE toxin-antitoxin system suppresses virulence in Xylella fastidiosa

    Science.gov (United States)

    Xylella fastidiosa, the causal agent of a number agriculturally important plant diseases, encodes multiple toxin-antitoxin (TA) systems. TA modules consist of a toxin protein co-expressed with a specific antitoxin, and are often acquired through horizontal gene transfer. Antitoxin molecules (RNA or ...

  14. Geraniol synthase whose mRNA is induced by host-selective ACT-toxin in the ACT-toxin-insensitive rough lemon (Citrus jambhiri).

    Science.gov (United States)

    Shishido, Hodaka; Miyamoto, Yoko; Ozawa, Rika; Taniguchi, Shiduku; Takabayashi, Junji; Akimitsu, Kazuya; Gomi, Kenji

    2012-09-15

    Host-selective toxins (HSTs) produced by some strains of Alternaria alternata are selectively toxic to certain cultivars of plants. However, the role of HSTs in toxin-insensitive plants is currently unknown. Here, we studied the role of ACT-toxin using an ACT-toxin producing A. alternata strain SH20 and the ACT-toxin-insensitive plant rough lemon. Induction of some defense related genes in response to SH20 were faster or stronger than in response to the ACT-toxin deficient SH20 mutant. By sequencing subtractive PCR clones obtained from mRNA of rough lemon leaves inoculated with SH20 after subtraction with that of the ACT-toxin deficient SH20 mutant, we isolated the SH20-responsive genes in rough lemon. Among the SH20-responsive genes analyzed in this study, we isolated a terpene synthase (TPS) gene, RlemTPS3. We also determined that RlemTPS3 localizes to the chloroplast and produces the monoterpene geraniol. Copyright © 2012 Elsevier GmbH. All rights reserved.

  15. Beta2 toxin is not involved in in vitro cell cytotoxicity caused by human and porcine cpb2-harbouring Clostridium perfringens

    NARCIS (Netherlands)

    Allaart, J.G.|info:eu-repo/dai/nl/357077776; van Asten, A.J.A.M.; Vernooij, J.C.M.|info:eu-repo/dai/nl/340304596; Gröne, A.|info:eu-repo/dai/nl/304836141

    2014-01-01

    Clostridium perfringens is a common cause of intestinal disease in animals and humans. Its pathogenicity is attributed to the toxins it can produce, including the beta2 toxin. The presence of cpb2, the gene encoding the beta2 toxin, has been associated with diarrhoea in neonatal piglets and humans.

  16. Comparison of fatigue strength of C2 pedicle screws, C2 pars screws, and a hybrid construct in C1-C2 fixation.

    Science.gov (United States)

    Su, Brian W; Shimer, Adam L; Chinthakunta, Suresh; Salloum, Kanaan; Ames, Christopher P; Vaccaro, Alexander R; Bucklen, Brandon

    2014-01-01

    A biomechanical study comparing the fatigue strength of different types of C2 fixation in a C1-C2 construct. To determine the pullout strength of a C2 pedicle screw and C2 pars screw after cyclical testing and differentiate differences in stiffness pre- and post-cyclical loading of 3 different C1-C2 fixations. Some surgeons use a short C2 pars screw in a C1-C2 construct, because it is less technically demanding and/or when the vertebral artery is high riding. Difference in construct stiffness between use of bilateral C2 pedicle screws, bilateral C2 pars screws, or a hybrid construct is unknown. Biomechanical testing was performed on 15 specimens. A bicortical C1 lateral mass screw was used in combination with 1 of 3 methods of C2 fixation: (1) bilateral long C2 pedicle screws (LL), (2) bilateral 14-mm C2 pars screws (SS), and (3) unilateral long C2 pedicle screw with a contralateral 14-mm C2 pars screw (LS). Each construct was subject to 16,000 cycles to simulate the immediate postoperative period. Changes in motion in flexion-extension, lateral bending, and axial rotation were calculated. This was followed by pullout testing. The ability to limit range of motion significantly decreased after cyclical testing in flexion-extension, lateral bending, and axial rotation for all 3 groups. After loading, the LL and LS groups had less percentage of increase in motion in flexion-extension and lateral bending than the SS group. Overall, the average pullout strength of a pedicle screw was 92% stronger than a pars screw. C2 pedicle screws have twice the pullout strength of C2 pars screws after cyclical loading. In cases in which the anatomy limits placement of bilateral C2 pedicle screws, a construct using a unilateral C2 pedicle screw with a contralateral short pars screw is a viable option and compares favorably with a bilateral C2 pedicle screw construct. N/A.

  17. [Rapid-tests detection evaluation of Clostridium difficile toxins and microbiological investigation].

    Science.gov (United States)

    Nakagawa, Risa; Iinuma, Yoshitsugu; Yamamoto, Masaki; Matsumura, Yasufumi; Shirano, Michinori; Matsushima, Aki; Nagao, Miki; Saito, Takashi; Takakura, Shunji; Ito, Yutaka; Higuchi, Takeshi; Tanaka, Michio; Ichiyama, Satoshi

    2010-03-01

    We evaluated two rapid toxin tests for C. difficile combined with stool specimen cultures used from January 2006 to March 2009. Stool specimens numbered 877, 102 among which were from the cases of diagnosed clinical C. difficile-associated diarrhea (CDAD). Rapid toxin A 'Uniquick' detection kits were used until October 2007 and toxin A&B 'TOX A/B' detection kits thereafter. Clinical CDAD was considered the detection gold standard. Uniquick sensitivity, specificity, and positive and negative predictive values were 54.3%, 99.1%, 90.5%, and 93.2% while those for TOX A/B were 46.2%, 97.6%, 65.2%, and 95.0% and for culture 42.2%, 95.5%, 55.1%, and 92.6%. Rapid toxin tests tended to have better sensitivity than culture results although not significantly so, and Uniquick showed significantly better positive predictive value than TOX A/B or culture results. Among clinical CDAD cases, concordance with culture was 24.3% for Uniquick and 53.1% for TOX A/B. For stored strains, 27 were typed toxin A+B+ (48.1%), toxin A-B+ (37.0%) and toxin A-B- (14.8%) with toxin gene detection by PCR. Eight of the 10 toxin A-B+ strains were classified into two cluster by ribotyping, and 7 of those were detected in two hospital wards, indicated the possibility of nosocomial toxin A-B+ strain spread. The rapid toxin test for both toxins A and B should be used if toxin A-B+ predominate. Simultaneous culture testing may be useful for detecting clinical CDAD more accurately, however.

  18. Preponderance of toxigenic Escherichia coli in stool pathogens correlates with toxin detection in accessible drinking-water sources.

    Science.gov (United States)

    Igbokwe, H; Bhattacharyya, S; Gradus, S; Khubbar, M; Griswold, D; Navidad, J; Igwilo, C; Masson-Meyers, D; Azenabor, A A

    2015-02-01

    Since early detection of pathogens and their virulence factors contribute to intervention and control strategies, we assessed the enteropathogens in diarrhoea disease and investigated the link between toxigenic strains of Escherichia coli from stool and drinking-water sources; and determined the expression of toxin genes by antibiotic-resistant E. coli in Lagos, Nigeria. This was compared with isolates from diarrhoeal stool and water from Wisconsin, USA. The new Luminex xTAG GPP (Gastroplex) technique and conventional real-time PCR were used to profile enteric pathogens and E. coli toxin gene isolates, respectively. Results showed the pathogen profile of stool and indicated a relationship between E. coli toxin genes in water and stool from Lagos which was absent in Wisconsin isolates. The Gastroplex technique was efficient for multiple enteric pathogens and toxin gene detection. The co-existence of antibiotic resistance with enteroinvasive E. coli toxin genes suggests an additional prognostic burden on patients.

  19. β‐Taxilin participates in differentiation of C2C12 myoblasts into myotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, Hiroshi; Makiyama, Tomohiko; Nogami, Satoru; Horii, Yukimi [Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu-town, Tochigi 321-0293 (Japan); Akasaki, Kenji [Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292 (Japan); Shirataki, Hiromichi, E-mail: hiro-sh@dokkyomed.ac.jp [Department of Molecular and Cell Biology, Graduate school of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu-town, Tochigi 321-0293 (Japan)

    2016-07-15

    Myogenesis is required for the development of skeletal muscle. Accumulating evidence indicates that the expression of several genes are upregulated during myogenesis and these genes play pivotal roles in myogenesis. However, the molecular mechanism underlying myogenesis is not fully understood. In this study, we found that β-taxilin, which is specifically expressed in the skeletal muscle and heart tissues, was progressively expressed during differentiation of C2C12 myoblasts into myotubes, prompting us to investigate the role of β-taxilin in myogenesis. In C2C12 cells, knockdown of β-taxilin impaired the fusion of myoblasts into myotubes, and decreased the diameter of myotubes. We also found that β-taxilin interacted with dysbindin, a coiled-coil-containing protein. Knockdown of dysbindin conversely promoted the fusion of myoblasts into myotubes and increased the diameter of myotubes in C2C12 cells. Furthermore, knockdown of dysbindin attenuated the inhibitory effect of β-taxilin depletion on myotube formation of C2C12 cells. These results demonstrate that β-taxilin participates in myogenesis through suppressing the function of dysbindin to inhibit the differentiation of C2C12 myoblasts into myotubes. - Highlights: • β‐Taxilin is progressively expressed during differentiation of C2C12 cell. • Knockdown of β-taxilin impaired C2C12 myotube formation. • β‐Taxilin interacted with dysbindin. • Knockdown of dysbindin promoted C2C12 myotube formation. • The function of β-taxilin in C2C12 myotube formation depends on dysbindin.

  20. Heterologous Expression of Toxins from Bacterial Toxin-Antitoxin Systems in Eukaryotic Cells: Strategies and Applications

    Directory of Open Access Journals (Sweden)

    Chew Chieng Yeo

    2016-02-01

    Full Text Available Toxin-antitoxin (TA systems are found in nearly all prokaryotic genomes and usually consist of a pair of co-transcribed genes, one of which encodes a stable toxin and the other, its cognate labile antitoxin. Certain environmental and physiological cues trigger the degradation of the antitoxin, causing activation of the toxin, leading either to the death or stasis of the host cell. TA systems have a variety of functions in the bacterial cell, including acting as mediators of programmed cell death, the induction of a dormant state known as persistence and the stable maintenance of plasmids and other mobile genetic elements. Some bacterial TA systems are functional when expressed in eukaryotic cells and this has led to several innovative applications, which are the subject of this review. Here, we look at how bacterial TA systems have been utilized for the genetic manipulation of yeasts and other eukaryotes, for the containment of genetically modified organisms, and for the engineering of high expression eukaryotic cell lines. We also examine how TA systems have been adopted as an important tool in developmental biology research for the ablation of specific cells and the potential for utility of TA systems in antiviral and anticancer gene therapies.

  1. Heterologous Expression of Toxins from Bacterial Toxin-Antitoxin Systems in Eukaryotic Cells: Strategies and Applications.

    Science.gov (United States)

    Yeo, Chew Chieng; Abu Bakar, Fauziah; Chan, Wai Ting; Espinosa, Manuel; Harikrishna, Jennifer Ann

    2016-02-19

    Toxin-antitoxin (TA) systems are found in nearly all prokaryotic genomes and usually consist of a pair of co-transcribed genes, one of which encodes a stable toxin and the other, its cognate labile antitoxin. Certain environmental and physiological cues trigger the degradation of the antitoxin, causing activation of the toxin, leading either to the death or stasis of the host cell. TA systems have a variety of functions in the bacterial cell, including acting as mediators of programmed cell death, the induction of a dormant state known as persistence and the stable maintenance of plasmids and other mobile genetic elements. Some bacterial TA systems are functional when expressed in eukaryotic cells and this has led to several innovative applications, which are the subject of this review. Here, we look at how bacterial TA systems have been utilized for the genetic manipulation of yeasts and other eukaryotes, for the containment of genetically modified organisms, and for the engineering of high expression eukaryotic cell lines. We also examine how TA systems have been adopted as an important tool in developmental biology research for the ablation of specific cells and the potential for utility of TA systems in antiviral and anticancer gene therapies.

  2. Detection of the mosquitocidal toxin genes encoding Cry11 proteins from Bacillus thuringiensis using a novel PCR-RFLP method Detección de genes que codifican proteínas mosquitocidas Cry11 de Bacillus thuringiensis mediante un método de PCR-RFLP novedoso

    Directory of Open Access Journals (Sweden)

    D. H. Sauka

    2010-02-01

    Full Text Available A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP method for detection of cry11 genes from Bacillus thuringiensis was established. Based on the analysis of conserved regions of the cry11 genes, 2 oligonucleotide primers were designed to amplify a 1459-bp fragment of the cry11Aa gene, and a 1471-bp of the cry11Ba and cry11Bb genes. The amplification products were digested with restriction endonuclease HinfI. Exotic B. thuringiensis strains and native isolates collected from soils, leaves and stored product dust of Argentina were analyzed to study the distribution of cry11 genes. The PCR-RFLP patterns revealed the detection of cry11 genes in 3 of 64 exotic strains and in 10 of 107 native B. thuringiensis isolates tested. Just the cry11Aa gene subclass was detected among these bacteria. Since the methodology was also developed to detect cry11Ba and cry11Bb genes, an experimental future confirmation will be required. Based on the results obtained, the PCR-RFLP method presented may be a valuable tool for specific detection of the mosquitocidal toxin genes encoding Cry11 proteins from B. thuringiensis.En el presente estudio se estableció una estrategia basada en la amplificación génica (PCR y el posterior análisis de restricción (RFLP para detectar todos los genes cry11 de Bacillus thuringiensis informados hasta ahora. De acuerdo con el análisis de las regiones conservadas en los genes cry11, se diseñaron dos cebadores para amplificar un fragmento de 1459 pb de los genes cry11Aa y un fragmento de 1471 pb de los genes cry11Ba y cry11Bb. Los productos de la amplificación fueron digeridos con la enzima de restricción HinfI. Se analizaron cepas exóticas de B. thuringiensis y aislamientos nativos de Argentina obtenidos a partir de muestras de suelos, hojas y polvillo de silos, para estudiar la distribución de los genes cry11. Los patrones de PCR-RFLP revelaron la presencia de genes cry11 en 3 de las 64 cepas ex

  3. Theophylline Regulates Inflammatory and Neurotrophic factor Signals in Functional Recovery after C2-Hemisection in Adult Rats

    Science.gov (United States)

    Singh, LP; Devi, TS; Nantwi, KD

    2012-01-01

    Recovery of respiratory activity in an upper cervical hemisection model (C2H) of spinal cord injury (SCI) can be induced by systemic theophylline administration 24–48 h after injury. The objectives in the present study are (1) to identify pro-inflammatory and neurotrophic factors expressed after C2H and (2) molecular signals involved in functional recovery. Four groups of adult female rats classified as (i) sham (SH) controls, (ii) subjected to a left C2 hemisection (C2H) only, (iii) C2H rats administered theophylline for 3 consecutive days 2 days after C2H (C2H-T Day 5) and (iv) C2H rats treated with theophylline for 3 consecutive days 2 days after C2H and then weaned for 12 days (C2H-T Day 17) prior to assessment of respiratory function and molecular analysis were employed. Corresponding Sham controls, C2H untreated (vehicle only controls) and C2H treated (theophylline) rats were sacrificed, C3-C6 spinal cord segments quickly dissected and left (ipsilateral) hemi spinal cord and right (contralateral) hemi spinal cord were separately harvested 2 days post surgery. SHAM operated and C2H untreated-controls corresponding to C2H-T Day 5 and C2H-T Day 17 rats, respectively, were prepared similarly. Messenger RNA levels for pro-inflammatory genes (TXNIP, IL-1β, TNF-α and iNOS) and neurotrophic and survival factors (BDNF, GDNF, and Bcl2) were analyzed by real time quantitative PCR. Gene expression pattern was unaltered in SH rats. TXNIP, iNOS, BDNF, GDNF and Bcl2 mRNA levels were significantly increased in the ipsilateral hemi spinal cord in C2H rats. BDNF, GDNF and Bcl2 levels remained elevated in the ipsilateral hemi spinal cord in C2H-T Day 5 rats. In this same group, there was further enhancement in TXNIP and IL-1β while iNOS returned to basal levels. Theophylline increased DNA binding activity of transcription factors - cyclic AMP responsive element (CRE) binding protein (CREB) and pro-inflammatory NF-κB. Messenger RNA levels for all genes returned to basal

  4. Food toxin detection with atomic force microscope

    Science.gov (United States)

    Externally introduced toxins or internal spoilage correlated pathogens and their metabolites are all potential sources of food toxins. To prevent and protect unsafe food, many food toxin detection techniques have been developed to detect various toxins for quality control. Although several routine m...

  5. [Shiga toxin and tetanus toxin as a potential biologic weapon].

    Science.gov (United States)

    Toczyska, Izabela; Płusa, Tadeusz

    2015-09-01

    Toxins produced by the bacteria are of particular interest as potential cargo combat possible for use in a terrorist attack or war. Shiga toxin is usually produced by shiga toxigenic strains of Escherichia coli (STEC - shigatoxigenic Escherichia coli). To infection occurs mostly after eating contaminated beef. Clinical syndromes associated with Shiga toxin diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS - hemolytic uremic syndrome) or thrombotic thrombocytopenic purpura. Treatment is symptomatic. In HUS, in which mortality during an epidemic reaches 20%, extending the kidney injury dialysis may be necessary. Exposure to tetanus toxin produced by Clostridium tetani, resulting in the most generalized tetanus, characterized by increased muscle tension and painful contractions of individual muscle groups. In the treatment beyond symptomatic behavior (among others spasticity medications, anticonvulsants, muscle relaxants) is used tetanus antitoxin and antibiotics (metronidazole choice). A common complication is acute respiratory failure - then it is necessary to implement mechanical ventilation. © 2015 MEDPRESS.

  6. EXO70C2 is a key regulatory factor for optimal tip growth of pollen

    KAUST Repository

    Synek, Lukas

    2017-03-30

    The exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.

  7. PI3K-C2α knockdown decreases autophagy and maturation of endocytic vesicles.

    Directory of Open Access Journals (Sweden)

    Nathan M Merrill

    Full Text Available Phosphoinositide 3-kinase (PI3K family members are involved in diverse cellular fates including cell growth, proliferation, and survival. While many molecular details are known about the Class I and III PI3Ks, less is known about the Class II PI3Ks. To explore the function of all eight PI3K isoforms in autophagy, we knock down each gene individually and measure autophagy. We find a significant decrease in autophagy following siRNA-mediated PIK3C2A (encoding the Class 2 PI3K, PI3K-C2α knockdown. This defective autophagy is rescued by exogenous PI3K-C2α, but not kinase-dead PI3K-C2α. Using confocal microscopy, we probe for markers of endocytosis and autophagy, revealing that PI3K-C2α colocalizes with markers of endocytosis. Though endocytic uptake is intact, as demonstrated by transferrin labeling, PIK3C2A knockdown results in vesicle accumulation at the recycling endosome. We isolate distinct membrane sources and observe that PI3K-C2α interacts with markers of endocytosis and autophagy, notably ATG9. Knockdown of either PIK3C2A or ATG9A/B, but not PI3KC3, results in an accumulation of transferrin-positive clathrin coated vesicles and RAB11-positive vesicles at the recycling endosome. Taken together, these results support a role for PI3K-C2α in the proper maturation of endosomes, and suggest that PI3K-C2α may be a critical node connecting the endocytic and autophagic pathways.

  8. The Occurrence of Photorhabdus-Like Toxin Complexes in Bacillus thuringiensis

    OpenAIRE

    Blackburn, Michael B.; Martin, Phyllis A. W.; Daniel Kuhar; Farrar, Robert R.; Gundersen-Rindal, Dawn E.

    2011-01-01

    Recently, genomic sequencing of a Bacillus thuringiensis (Bt) isolate from our collection revealed the presence of an apparent operon encoding an insecticidal toxin complex (Tca) similar to that first described from the entomopathogen Photorhabdus luminescens. To determine whether these genes are widespread among Bt strains, we screened isolates from the collection for the presence of tccC, one of the genes needed for the expression of fully functional toxin complexes. Among 81 isolates chose...

  9. The role of Campylobacter jejuni cytolethal distending toxin in gastroenteritis

    DEFF Research Database (Denmark)

    Mortensen, Ninell P; Schiellerup, Peter; Boisen, Nadia

    2011-01-01

    The role of Campylobacter jejuni cytolethal distending toxin (CDT) on clinical outcome after gastroenteritis was investigated. Clinical data, blood serum samples, and Campylobacter spp. isolated, from each of 30 patients were collected over a period of 6 months. The CDT encoding genes, cdt......ABC, characterized by PCR, revealed that all but one of the C. jejuni strains had the wild-type sequence. Sequencing of cdtABC from this strain showed two major deletions. From all of the strains, CDT titers were determined, and toxin neutralizing antibodies were documented using an in vitro assay. Three...

  10. Tolevamer, an anionic polymer, neutralizes toxins produced by the BI/027 strains of Clostridium difficile.

    Science.gov (United States)

    Hinkson, Paul L; Dinardo, Carol; DeCiero, Daniel; Klinger, Jeffrey D; Barker, Robert H

    2008-06-01

    Clostridium difficile-associated diarrhea (CDAD) is caused by the toxins the organism produces when it overgrows in the colon as a consequence of antibiotic depletion of normal flora. Conventional antibiotic treatment of CDAD increases the likelihood of recurrent disease by again suppressing normal bacterial flora. Tolevamer, a novel toxin-binding polymer, was developed to ameliorate the disease without adversely affecting normal flora. In the current study, tolevamer was tested for its ability to neutralize clostridial toxins produced by the epidemic BI/027 strains, thereby preventing toxin-mediated tissue culture cell rounding. The titers of toxin-containing C. difficile culture supernatants were determined using confluent cell monolayers, and then the supernatants were used in assays containing dilutions of tolevamer to determine the lowest concentration of tolevamer that prevented > or =90% cytotoxicity. Tolevamer neutralized toxins in the supernatants of all C. difficile strains tested. Specific antibodies against the large clostridial toxins TcdA and TcdB also neutralized the cytopathic effect, suggesting that tolevamer is specifically neutralizing these toxins and that the binary toxin (whose genes are carried by the BI/027 strains) is not a significant source of cytopathology against tissue culture cells in vitro.

  11. Prevalence and Toxin Characteristics of Bacillus thuringiensis Isolated from Organic Vegetables.

    Science.gov (United States)

    Kim, Jung-Beom; Choi, Ok-Kyung; Kwon, Sun-Mok; Cho, Seung-Hak; Park, Byung-Jae; Jin, Na Young; Yu, Yong Man; Oh, Deog-Hwan

    2017-08-28

    The prevalence and toxin characteristics of Bacillus thuringiensis isolated from 39 organic vegetables were investigated. B. thuringiensis was detected in 30 out of the 39 organic vegetables (76.9%) with a mean value of 2.60 log CFU/g. Twenty-five out of the 30 B. thuringiensis isolates (83.3%) showed insecticidal toxicity against Spodoptera exigua. The hblCDA, nheABC, and entFM genes were found to be the major toxin genes, but the ces gene was not detected in any of the tested B. thuringiensis isolates. The hemolysin BL enterotoxin was detected in all 30 B. thuringiensis isolates (100%). The non-hemolytic enterotoxin complex was found in 27 out of 30 B. thuringiensis isolates (90.0%). The B. thuringiensis tested in this study had similar toxin gene characteristics to B. cereus, which possessed more than one toxin gene. B. thuringiensis could have the potential risk of foodborne illness based on the toxin genes and toxin-producing ability.

  12. Rate constant for the reaction C2H5 + HBr → C2H6 + Br.

    Science.gov (United States)

    Golden, David M; Peng, Jingping; Goumri, A; Yuan, J; Marshall, Paul

    2012-06-21

    RRKM theory has been employed to analyze the kinetics of the title reaction, in particular, the once-controversial negative activation energy. Stationary points along the reaction coordinate were characterized with coupled cluster theory combined with basis set extrapolation to the complete basis set limit. A shallow minimum, bound by 9.7 kJ mol(-1) relative to C(2)H(5) + HBr, was located, with a very small energy barrier to dissociation to Br + C(2)H(6). The transition state is tight compared to the adduct. The influence of vibrational anharmonicity on the kinetics and thermochemistry of the title reaction were explored quantitatively. With adjustment of the adduct binding energy by ∼4 kJ mol(-1), the computed rate constants may be brought into agreement with most experimental data in the literature, including new room-temperature results described here. There are indications that at temperatures above those studied experimentally, the activation energy may switch from negative to positive.

  13. Trichothecene triangle: toxins, genes, and plant disease

    Science.gov (United States)

    Trichothecenes are a family of sesquiterpene epoxides that inhibit eukaryotic protein synthesis. These mycotoxins are produced in Fusarium-infested grains such as corn, wheat, and barley, and ingestion of contaminated grain can result in a variety of symptoms including diarrhea, hemorrhaging and fee...

  14. First-Principles Study of Vacancies in Ti3SiC2 and Ti3AlC2

    Directory of Open Access Journals (Sweden)

    Hui Wang

    2017-01-01

    Full Text Available MAX phase materials have attracted increased attention due to their unique combination of ceramic and metallic properties. In this study, the properties of vacancies in Ti3AlC2 and Ti3SiC2, which are two of the most widely studied MAX phases, were investigated using first-principles calculations. Our calculations indicate that the stabilities of vacancies in Ti3SiC2 and Ti3AlC2 differ greatly from those previously reported for Cr2AlC. The order of the formation energies of vacancies is VTi(a > VTi(b > VC > VA for both Ti3SiC2 and Ti3AlC2. Although the diffusion barriers for Ti3SiC2 and Ti3AlC2 are similar (~0.95 eV, the properties of their vacancies are significantly different. Our results show that the vacancy–vacancy interaction is attractive in Ti3AlC2 but repulsive in Ti3SiC2. The introduction of VTi and VC vacancies results in the lattice constant c along the [0001] direction increasing for both Ti3SiC2 and Ti3AlC2. In contrast, the lattice constant c decreases significantly when VA are introduced. The different effect of VA on the lattice constants is explained by enhanced interactions of nearby Ti layers.

  15. Analysis list: NR2C2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NR2C2 Blood,Liver,Uterus + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/tar...get/NR2C2.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/NR2C2.5.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/target/NR2C2.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/NR2C2.Blood....tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/NR2C2.Liver.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/colo/NR2C2.Uterus.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg1

  16. Clostridium difficile toxin CDT induces formation of microtubule-based protrusions and increases adherence of bacteria.

    Directory of Open Access Journals (Sweden)

    Carsten Schwan

    2009-10-01

    Full Text Available Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by production of the Rho GTPase-glucosylating toxins A and B. Recently emerging hypervirulent Clostridium difficile strains additionally produce the binary ADP-ribosyltransferase toxin CDT (Clostridium difficile transferase, which ADP-ribosylates actin and inhibits actin polymerization. Thus far, the role of CDT as a virulence factor is not understood. Here we report by using time-lapse- and immunofluorescence microscopy that CDT and other binary actin-ADP-ribosylating toxins, including Clostridium botulinum C2 toxin and Clostridium perfringens iota toxin, induce redistribution of microtubules and formation of long (up to >150 microm microtubule-based protrusions at the surface of intestinal epithelial cells. The toxins increase the length of decoration of microtubule plus-ends by EB1/3, CLIP-170 and CLIP-115 proteins and cause redistribution of the capture proteins CLASP2 and ACF7 from microtubules at the cell cortex into the cell interior. The CDT-induced microtubule protrusions form a dense meshwork at the cell surface, which wrap and embed bacterial cells, thereby largely increasing the adherence of Clostridia. The study describes a novel type of microtubule structure caused by less efficient microtubule capture and offers a new perspective for the pathogenetic role of CDT and other binary actin-ADP-ribosylating toxins in host-pathogen interactions.

  17. Evaluation of three rapid assays for detection of Clostridium difficile toxin A and toxin B in stool specimens.

    Science.gov (United States)

    Rüssmann, H; Panthel, K; Bader, R-C; Schmitt, C; Schaumann, R

    2007-02-01

    Diagnosis of Clostridium difficile-associated disease continues to be difficult for clinical microbiology laboratories. The aim of this study was to evaluate the performance of three enzyme immunoassays for detection of C. difficile toxins A and B: the recently marketed rapid enzyme immunoassay Ridascreen Clostridium difficile Toxin A/B (R-Biopharm, Darmstadt, Germany) and two established enzyme immunoassays, the C. difficile Tox A/B II Assay (TechLab, Blacksburg, VA, USA) and the ProSpecT C. difficile Toxin A/B Microplate Assay (Remel, Lenexa, KS, USA). Stool specimens (n = 383) from patients with a clinical diagnosis of antibiotic-associated diarrhea were examined by these three enzyme immunoassays and were additionally cultured for C. difficile on selective agar. Samples giving discordant enzyme immunoassay results underwent confirmatory testing by tissue culture cytotoxin B assay and by PCR for toxin A (tcdA) and toxin B (tcdB) genes from C. difficile. Using the criteria adopted for this study, 60 (15.7%) samples tested positive for toxins A and/or B. Sensitivity and specificity of the enzyme immunoassays were, respectively, 88.3 and 100% for the TechLab enzyme immunoassay, 91.7 and 100% for the R-Biopharm enzyme immunoassay, and 93.3 and 100% for the Remel enzyme immunoassay. The differences between these results are statistically not significant (p > 0.05). The results show that all three enzyme immunoassays are acceptable tests for the detection of C. difficile toxins A and B directly in fecal specimens or in toxigenic cultures.

  18. Cytolytic toxin Cyt1Aa of Bacillus thuringiensis synergizes the mosquitocidal toxin Mtx1 of Bacillus sphaericus.

    Science.gov (United States)

    Zhang, Beihua; Liu, Ming; Yang, Yankun; Yuan, Zhiming

    2006-09-01

    Using the shuttle vector pBU4, the mosquitocidal toxin gene mtx1 from Bacillus sphaericus strain SSII-1 was introduced into an acrystalliferous strain of B. thuringiensis both individually and in combination with the accessory protein gene p20 and the cytolytic protein gene cyt1Aa from B. thuringiensis subsp. israelensis. Bioassay results indicated that the recombinants B-pMT4(Mtx1) and B-pMT9(Mtx1), both individually containing mtx1, had moderate toxicities to binary toxin susceptible and binary toxin resistant Culex quinquefasciatus larvae during the vegetative growth stage, but that their toxicities declined rapidly during the sporulation phase. The LC50 values were 2.5 and 4.8 mg/ml respectively, against 3-4 instar susceptible and resistant larvae for the final sporulated cultures of recombinants B-pMT9(Mtx1), and little toxicity was detected for B-pMT4(Mtx1). Meanwhile, the recombinant B-pMPX2(Mtx1+Cyt1Aa) expressing Mtx1, P20 alone, and Cyt1Aa in combination had stable toxicities during both the vegetative phase and the sporulation phase, with a LC50 ranging from 0.45-0.58 mg/ml. Furthermore, expression of Cyt1Aa appeared to enhance the activity of Mtx1 to target mosquito larvae, suggesting a synergism between Cyt1Aa and Mtx1 toxins.

  19. Cytotoxic Effects of Environmental Toxins on Human Glial Cells.

    Science.gov (United States)

    D'Mello, Fiona; Braidy, Nady; Marçal, Helder; Guillemin, Gilles; Rossi, Fanny; Chinian, Mirielle; Laurent, Dominique; Teo, Charles; Neilan, Brett A

    2017-02-01

    Toxins produced by cyanobacteria and dinoflagellates have increasingly become a public health concern due to their degenerative effects on mammalian tissue and cells. In particular, emerging evidence has called attention to the neurodegenerative effects of the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA). Other toxins such as the neurotoxins saxitoxin and ciguatoxin, as well as the hepatotoxic microcystin, have been previously shown to have a range of effects upon the nervous system. However, the capacity of these toxins to cause neurodegeneration in human cells has not, to our knowledge, been previously investigated. This study aimed to examine the cytotoxic effects of BMAA, microcystin-LR (MC-LR), saxitoxin (STX) and ciguatoxin (CTX-1B) on primary adult human astrocytes. We also demonstrated that α-lipoate attenuated MC-LR toxicity in primary astrocytes and characterised changes in gene expression which could potentially be caused by these toxins in primary astrocytes. Herein, we are the first to show that all of these toxins are capable of causing physiological changes consistent with neurodegeneration in glial cells, via oxidative stress and excitotoxicity, leading to a reduction in cell proliferation culminating in cell death. In addition, MC-LR toxicity was reduced significantly in astrocytes-treated α-lipoic acid. While there were no significant changes in gene expression, many of the probes that were altered were associated with neurodegenerative disease pathogenesis. Overall, this is important in advancing our current understanding of the mechanism of toxicity of MC-LR on human brain function in vitro, particularly in the context of neurodegeneration.

  20. Endocytosis‒Mediated Invasion and Pathogenicity of Streptococcus agalactiae in Rat Cardiomyocyte (H9C2.

    Directory of Open Access Journals (Sweden)

    Sharma Pooja

    Full Text Available Streptococcus agalactiae infection causes high mortality in cardiovascular disease (CVD patients, especially in case of setting prosthetic valve during cardiac surgery. However, the pathogenesis mechanism of S. agalactiae associate with CVD has not been well studied. Here, we have demonstrated the pathogenicity of S. agalactiae in rat cardiomyocytes (H9C2. Interestingly, both live and dead cells of S. agalactiae were uptaken by H9C2 cells. To further dissect the process of S. agalactiae internalization, we chemically inhibited discrete parts of cellular uptake system in H9C2 cells using genistein, chlorpromazine, nocodazole and cytochalasin B. Chemical inhibition of microtubule and actin formation by nocodazole and cytochalasin B impaired S. agalactiae internalization into H9C2 cells. Consistently, reverse‒ transcription PCR (RT‒PCR and quantitative real time‒PCR (RT-qPCR analyses also detected higher levels of transcripts for cytoskeleton forming genes, Acta1 and Tubb5 in S. agalactiae‒infected H9C2 cells, suggesting the requirement of functional cytoskeleton in pathogenesis. Host survival assay demonstrated that S. agalactiae internalization induced cytotoxicity in H9C2 cells. S. agalactiae cells grown with benzyl penicillin reduced its ability to internalize and induce cytotoxicity in H9C2 cells, which could be attributed with the removal of surface lipoteichoic acid (LTA from S. agalactiae. Further, the LTA extracted from S. agalactiae also exhibited dose‒dependent cytotoxicity in H9C2 cells. Taken together, our data suggest that S. agalactiae cells internalized H9C2 cells through energy‒dependent endocytic processes and the LTA of S. agalactiae play major role in host cell internalization and cytotoxicity induction.

  1. C2H2 type of zinc finger transcription factors in foxtail millet define response to abiotic stresses.

    Science.gov (United States)

    Muthamilarasan, Mehanathan; Bonthala, Venkata Suresh; Mishra, Awdhesh Kumar; Khandelwal, Rohit; Khan, Yusuf; Roy, Riti; Prasad, Manoj

    2014-09-01

    C2H2 type of zinc finger transcription factors (TFs) play crucial roles in plant stress response and hormone signal transduction. Hence considering its importance, genome-wide investigation and characterization of C2H2 zinc finger proteins were performed in Arabidopsis, rice and poplar but no such study was conducted in foxtail millet which is a C4 Panicoid model crop well known for its abiotic stress tolerance. The present study identified 124 C2H2-type zinc finger TFs in foxtail millet (SiC2H2) and physically mapped them onto the genome. The gene duplication analysis revealed that SiC2H2s primarily expanded in the genome through tandem duplication. The phylogenetic tree classified these TFs into five groups (I-V). Further, miRNAs targeting SiC2H2 transcripts in foxtail millet were identified. Heat map demonstrated differential and tissue-specific expression patterns of these SiC2H2 genes. Comparative physical mapping between foxtail millet SiC2H2 genes and its orthologs of sorghum, maize and rice revealed the evolutionary relationships of C2H2 type of zinc finger TFs. The duplication and divergence data provided novel insight into the evolutionary aspects of these TFs in foxtail millet and related grass species. Expression profiling of candidate SiC2H2 genes in response to salinity, dehydration and cold stress showed differential expression pattern of these genes at different time points of stresses.

  2. Targeted toxins in brain tumor therapy.

    Science.gov (United States)

    Li, Yan Michael; Hall, Walter A

    2010-11-01

    Targeted toxins, also known as immunotoxins or cytotoxins, are recombinant molecules that specifically bind to cell surface receptors that are overexpressed in cancer and the toxin component kills the cell. These recombinant proteins consist of a specific antibody or ligand coupled to a protein toxin. The targeted toxins bind to a surface antigen or receptor overexpressed in tumors, such as the epidermal growth factor receptor or interleukin-13 receptor. The toxin part of the molecule in all clinically used toxins is modified from bacterial or plant toxins, fused to an antibody or carrier ligand. Targeted toxins are very effective against cancer cells resistant to radiation and chemotherapy. They are far more potent than any known chemotherapy drug. Targeted toxins have shown an acceptable profile of toxicity and safety in early clinical studies and have demonstrated evidence of a tumor response. Currently, clinical trials with some targeted toxins are complete and the final results are pending. This review summarizes the characteristics of targeted toxins and the key findings of the important clinical studies with targeted toxins in malignant brain tumor patients. Obstacles to successful treatment of malignant brain tumors include poor penetration into tumor masses, the immune response to the toxin component and cancer heterogeneity. Strategies to overcome these limitations are being pursued in the current generation of targeted toxins.

  3. A genetic switch controls the production of flagella and toxins in Clostridium difficile.

    Science.gov (United States)

    Anjuwon-Foster, Brandon R; Tamayo, Rita

    2017-03-01

    In the human intestinal pathogen Clostridium difficile, flagella promote adherence to intestinal epithelial cells. Flagellar gene expression also indirectly impacts production of the glucosylating toxins, which are essential to diarrheal disease development. Thus, factors that regulate the expression of the flgB operon will likely impact toxin production in addition to flagellar motility. Here, we report the identification a "flagellar switch" that controls the phase variable production of flagella and glucosylating toxins. The flagellar switch, located upstream of the flgB operon containing the early stage flagellar genes, is a 154 bp invertible sequence flanked by 21 bp inverted repeats. Bacteria with the sequence in one orientation expressed flagellum and toxin genes, produced flagella, and secreted the toxins ("flg phase ON"). Bacteria with the sequence in the inverse orientation were attenuated for flagellar and toxin gene expression, were aflagellate, and showed decreased toxin secretion ("flg phase OFF"). The orientation of the flagellar switch is reversible during growth in vitro. We provide evidence that gene regulation via the flagellar switch occurs post-transcription initiation and requires a C. difficile-specific regulatory factor to destabilize or degrade the early flagellar gene mRNA when the flagellar switch is in the OFF orientation. Lastly, through mutagenesis and characterization of flagellar phase locked isolates, we determined that the tyrosine recombinase RecV, which catalyzes inversion at the cwpV switch, is also responsible for inversion at the flagellar switch in both directions. Phase variable flagellar motility and toxin production suggests that these important virulence factors have both advantageous and detrimental effects during the course of infection.

  4. Inositol hexakisphosphate-dependent processing of Clostridium sordellii lethal toxin and Clostridium novyi alpha-toxin.

    Science.gov (United States)

    Guttenberg, Gregor; Papatheodorou, Panagiotis; Genisyuerek, Selda; Lü, Wei; Jank, Thomas; Einsle, Oliver; Aktories, Klaus

    2011-04-29

    Clostridium sordellii lethal toxin and Clostridium novyi α-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (α-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP(6)) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP(6) (<1 μM), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi α-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and α-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of α-toxin) were identified. Affinity of the CPDs for binding InsP(6) was determined by isothermal titration calorimetry. In contrast to full-length toxin B and α-toxin, autocatalytic cleavage and InsP(6) binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi α-toxin are InsP(6)-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP(6) and subsequent processing of the toxin.

  5. Inositol Hexakisphosphate-dependent Processing of Clostridium sordellii Lethal Toxin and Clostridium novyi α-Toxin*

    Science.gov (United States)

    Guttenberg, Gregor; Papatheodorou, Panagiotis; Genisyuerek, Selda; Lü, Wei; Jank, Thomas; Einsle, Oliver; Aktories, Klaus

    2011-01-01

    Clostridium sordellii lethal toxin and Clostridium novyi α-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (α-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP6) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP6 (<1 μm), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi α-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and α-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of α-toxin) were identified. Affinity of the CPDs for binding InsP6 was determined by isothermal titration calorimetry. In contrast to full-length toxin B and α-toxin, autocatalytic cleavage and InsP6 binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi α-toxin are InsP6-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP6 and subsequent processing of the toxin. PMID:21385871

  6. 26 CFR 1.1402(c)-2 - Public office.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 12 2010-04-01 2010-04-01 false Public office. 1.1402(c)-2 Section 1.1402(c)-2...) INCOME TAXES Tax on Self-Employment Income § 1.1402(c)-2 Public office. (a) In general—(1) General rule... public office does not constitute a trade or business. (2) Fee basis public officials—(i) In general. If...

  7. Comparative genomics evidence that only protein toxins are tagging bad bugs

    Directory of Open Access Journals (Sweden)

    Kalliopi eGeorgiades

    2011-10-01

    Full Text Available The term toxin was introduced by Roux and Yersin and describes macromolecular substances that, when produced during infection or when introduced parenterally or orally, cause an impairment of physiological functions that lead to disease or to the death of the infected organism. Long after the discovery of toxins, early genetic studies on bacterial virulence demonstrated that removing a certain number of genes from pathogenic bacteria decreases their capacity to infect hosts. Each of the removed factors was therefore referred to as a virulence factor, and it was speculated that non-pathogenic bacteria lack such supplementary factors. However, many recent comparative studies demonstrate that the specialization of bacteria to eukaryotic hosts is associated with massive gene loss. We recently demonstrated that the only features that seem to characterize 12 epidemic bacteria are toxin-antitoxin (TA modules, which are addiction molecules in host bacteria. In this study, we investigated if protein toxins are indeed the only molecules specific to pathogenic bacteria by comparing 14 epidemic bacterial killers (bad bugs with their 14 closest non-epidemic relatives (controls. We found protein toxins in significantly more elevated numbers in all of the bad bugs. For the first time, statistical principal components analysis, including genome size, GC%, TA modules, restriction enzymes and toxins, revealed that toxins are the only proteins other than TA modules that are correlated with the pathogenic character of bacteria. Moreover, intracellular toxins appear to be more correlated with the pathogenic character of bacteria than secreted toxins. In conclusion, we hypothesize that the only truly identifiable phenomena, witnessing the convergent evolution of the most pathogenic bacteria for humans are the loss of metabolic activities, i.e., the outcome of the loss of regulatory and transcription factors and the presence of protein toxins, alone or coupled as TA

  8. Ribosomal biosynthesis of the cyclic peptide toxins of Amanita mushrooms.

    Science.gov (United States)

    Walton, Jonathan D; Hallen-Adams, Heather E; Luo, Hong

    2010-01-01

    Some species of mushrooms in the genus Amanita are extremely poisonous and frequently fatal to mammals including humans and dogs. Their extreme toxicity is due to amatoxins such as alpha- and beta-amanitin. Amanita mushrooms also biosynthesize a chemically related group of toxins, the phallotoxins, such as phalloidin. The amatoxins and phallotoxins (collectively known as the Amanita toxins) are bicyclic octa- and heptapeptides, respectively. Both contain an unusual Trp-Cys crossbridge known as tryptathionine. We have shown that, in Amanita bisporigera, the amatoxins and phallotoxins are synthesized as proproteins on ribosomes and not by nonribosomal peptide synthetases. The proproteins are 34-35 amino acids in length and have no predicted signal peptides. The genes for alpha-amanitin (AMA1) and phallacidin (PHA1) are members of a large family of related genes, characterized by highly conserved amino acid sequences flanking a hypervariable "toxin" region. The toxin regions are flanked by invariant proline (Pro) residues. An enzyme that could cleave the proprotein of phalloidin was purified from the phalloidin-producing lawn mushroom Conocybe apala. The enzyme is a serine protease in the prolyl oligopeptidase (POP) subfamily. The same enzyme cuts at both Pro residues to release the linear hepta- or octapeptide.

  9. Pilot Study on MAGE-C2 as a Potential Biomarker for Triple-Negative Breast Cancer

    Directory of Open Access Journals (Sweden)

    Qian Zhao

    2016-01-01

    Full Text Available Objective. In the current study, we measured the expression status of melanoma antigen gene c2 (MAGE-C2 in triple-negative breast cancer (TNBC and analyzed its prognostic with the clinical pathological features of patients with TNBC. Methods. The expressions statuses of MAGE-C2 were detected in TNBC tissues and paracarcinoma tissues by immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR, and western blotting. Then, we investigated the relationship of MAGE-C2 expression status and clinicopathological parameters of TNBC patients by the chi-squared test. Finally, we discussed the relations of MAGE-C2 expression state and prognosis of patients with TNBC by Kaplan-Meier method and Cox proportional hazards model. Results. High MAGE-C2 expression was found in 38.18% (42/110 of TNBC tissues. In adjacent tissues it was 9.09% (10/110. High MAGE-C2 expression in TNBC patients was closely associated with lymph node status, tumor node metastasis (TNM stage, and lymphovascular invasion (P<0.001. TNBC patients with high MAGE-C2 expression had significantly shorter survival time than low expression patients. We also found that age, lymph node status, TNM stage, lymphovascular invasion, and MAGE-C2 expression status were closely associated with overall survival of TNBC patients (P<0.05. Conclusion. High MAGE-C2 expression may serve as an independent prognostic factor for TNBC patients.

  10. Tightly Bound Binary Toxin in the Cell Wall of Bacillus sphaericus

    Science.gov (United States)

    Klein, Daniela; Uspensky, Igor; Braun, Sergei

    2002-01-01

    We have shown that urea-extracted cell wall of entomopathogenic Bacillus sphaericus 2297 and some other strains is a potent larvicide against Culex pipiens mosquitoes, with 50% lethal concentrations comparable to that of the well-known B. sphaericus binary toxin, with which it acts synergistically. The wall toxicity develops in B. sphaericus 2297 cultures during the late logarithmic stage, earlier than the appearance of the binary toxin crystal. It disappears with sporulation when the binary toxin activity reaches its peak. Disruption of the gene for the 42-kDa protein (P42) of the binary toxin abolishes both cell wall toxicity and crystal formation. However, the cell wall of B. sphaericus 2297, lacking P42, kills C. pipiens larvae when mixed with Escherichia coli cells expressing P42. Thus, the cell wall toxicity in strongly toxic B. sphaericus strains must be attributed to the presence in the cell wall of tightly bound 51-kDa (P51) and P42 binary toxin proteins. The synergism between binary toxin crystals and urea-treated cell wall preparations reflects suboptimal distribution of binary toxin subunits in both compartments. Binary toxin crystal is slightly deficient in P51, while cell wall is lacking in P42. PMID:12089007

  11. Discovery of Functional Toxin/Antitoxin Systems in Bacteria by Shotgun Cloning

    Energy Technology Data Exchange (ETDEWEB)

    Sberro, Hila; Leavitt, Azita; Kiro, Ruth; Koh, Eugene; Peleg, Yoav; Qimron, Udi; Sorek, Rotem

    2013-04-01

    Toxin-antitoxin (TA) modules, composed of a toxic protein and a counteracting antitoxin, play important roles in bacterial physiology. We examined the experimental insertion of 1.5 million genes from 388 microbial genomes into an Escherichia coli host using over 8.5 million random clones. This revealed hundreds of genes (toxins) that could only be cloned when the neighboring gene (antitoxin) was present on the same clone. Clustering of these genes revealed TA families widespread in bacterial genomes, some of which deviate from the classical characteristics previously described for such modules. Introduction of these genes into E. coli validated that the toxin toxicity is mitigated by the antitoxin. Infection experiments with T7 phage showed that two of the new modules can provide resistance against phage. Moreover, our experiments revealed an 'anti-defense' protein in phage T7 that neutralizes phage resistance. Our results expose active fronts in the arms race between bacteria and phage.

  12. Nanoparticle-mediated intracellular lipid accumulation during C2C12 cell differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, Tamotsu, E-mail: ttamotsu@shinshu-u.ac.jp [Department of Integrative Physiology and Bio-System Control, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Haniu, Hisao, E-mail: hhaniu@shinshu-u.ac.jp [Institute of Carbon Science and Technology, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

    2011-03-25

    Research highlights: {yields} HTT2800 has a significant effect on intracellular lipid accumulation. {yields} HTT2800 reduced muscle-specific genes and led to the emergence of adipocyte-related genes. {yields} HT2800 converts the differentiation pathway of C2C12 myoblasts to that of adipoblast-like cells. -- Abstract: In this report, we sought to elucidate whether multiwall carbon nanotubes are involved in the modulation of the proliferation and differentiation of the skeletal muscle cell line C2C12. Skeletal muscle is a major mass peripheral tissue that accounts for 40% of total body weight and 50% of energy consumption. We focused on the differentiation pathway of myoblasts after exposure to a vapor-grown carbon fiber, HTT2800, which is one of the most highly purified carbon nanotubes. This treatment leads in parallel to the expression of a typical adipose differentiation program. We found that HTT2800 stimulated intracellular lipid accumulation in C2C12 cells. We have also shown by quantified PCR analysis that the expression of adipose-related genes was markedly upregulated during HTT2800 exposure. Taken together, these results suggest that HTT2800 specifically converts the differentiation pathway of C2C12 myoblasts to that of adipoblast-like cells.

  13. Isotope effect in acetylene C2H2 and C2D2 rotations on Cu(001)

    Science.gov (United States)

    Shchadilova, Yulia E.; Tikhodeev, Sergei G.; Paulsson, Magnus; Ueba, Hiromu

    2014-04-01

    A comprehensive analysis of the elementary processes behind the scanning tunneling microscope controlled rotation of C2H2 and C2D2, isotopologues of a single acetylene molecule adsorbed on the Cu(001) surface, is given, with a focus on the isotope effects. With the help of density-functional theory we calculate the vibrational modes of C2H2 and C2D2 on Cu(001) and estimate the anharmonic couplings between them, using a simple strings-on-rods model. The probability of the elementary processes, nonlinear and combination band, is estimated using the Keldysh diagram technique. This allows us to clarify the main peculiarities and the isotope effects of the C2H2 and C2D2 on Cu(001) rotation, discovered in the pioneering work [B. C. Stipe et al., Phys. Rev. Lett. 81, 1263 (1998), 10.1103/PhysRevLett.81.1263], which have not been previously understood.

  14. Sea anemone toxins affecting voltage-gated sodium channels--molecular and evolutionary features.

    Science.gov (United States)

    Moran, Yehu; Gordon, Dalia; Gurevitz, Michael

    2009-12-15

    The venom of sea anemones is rich in low molecular weight proteinaceous neurotoxins that vary greatly in structure, site of action, and phyletic (insect, crustacean or vertebrate) preference. This toxic versatility likely contributes to the ability of these sessile animals to inhabit marine environments co-habited by a variety of mobile predators. Among these toxins, those that show prominent activity at voltage-gated sodium channels and are critical in predation and defense, have been extensively studied for more than three decades. These studies initially focused on the discovery of new toxins, determination of their covalent and folded structures, understanding of their mechanisms of action on different sodium channels, and identification of the primary sites of interaction of the toxins with their channel receptors. The channel binding site for Type I and the structurally unrelated Type III sea anemone toxins was identified as neurotoxin receptor site 3, a site previously shown to be targeted by scorpion alpha-toxins. The bioactive surfaces of toxin representatives from these two sea anemone types have been characterized by mutagenesis. These analyses pointed to heterogeneity of receptor site 3 at various sodium channels. A turning point in evolutionary studies of sea anemone toxins was the recent release of the genome sequence of Nematostella vectensis, which enabled analysis of the genomic organization of the corresponding genes. This analysis demonstrated that Type I toxins in Nematostella and other species are encoded by gene families and suggested that these genes developed by concerted evolution. The current review provides a brief historical description of the discovery and characterization of sea anemone toxins that affect voltage-gated sodium channels and delineates recent advances in the study of their structure-activity relationship and evolution.

  15. Comparative genomics of Shiga toxin encoding bacteriophages

    Directory of Open Access Journals (Sweden)

    Smith Darren L

    2012-07-01

    Full Text Available Abstract Background Stx bacteriophages are responsible for driving the dissemination of Stx toxin genes (stx across their bacterial host range. Lysogens carrying Stx phages can cause severe, life-threatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24B, commonly referred to as Ф24B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of Ф24B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages. Results The genome of the Stx2 encoding phage, Ф24B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic Escherichia coli (EHEC, however Ф24B possesses significant regions of heterogeneity, with implications for phage biology and behaviour. The Ф24B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system. Conclusions The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potential.

  16. Entry of Shiga toxin into cells

    DEFF Research Database (Denmark)

    Sandvig, Kirsten; van Deurs, Bo

    1994-01-01

    Cellebiologi, Shiga toxin, receptors, glycolipids, endocytosis, trans-Golgi network, endoplasmic reticulum, retrograde transport......Cellebiologi, Shiga toxin, receptors, glycolipids, endocytosis, trans-Golgi network, endoplasmic reticulum, retrograde transport...

  17. High pressure oxidation of C2H4/NO mixtures

    DEFF Research Database (Denmark)

    Giménez-López, J.; Alzueta, M.U.; Rasmussen, C.T.

    2011-01-01

    An experimental and kinetic modeling study of the interaction between C2H4 and NO has been performed under flow reactor conditions in the intermediate temperature range (600–900K), high pressure (60bar), and for stoichiometries ranging from reducing to oxidizing conditions. The main reaction...... pathways of the C2H4/O2/NOx conversion, the capacity of C2H4 to remove NO, and the influence of the presence of NOx on the C2H4 oxidation are analyzed. Compared to the C2H4/O2 system, the presence of NOx shifts the onset of reaction 75–150K to lower temperatures. The mechanism of sensitization involves...... is removed. This removal is partly explained by the reaction C2H3+NO→HCN+CH2O. However, a second removal mechanism is active in the 700–850K range, which is not captured by the chemical kinetic model. With the present thermochemistry and kinetics, neither formation of nitro-hydrocarbons (CH3NO2, C2H3NO2, C2H...

  18. Inhibition of cholera toxin and other AB toxins by polyphenolic compounds

    Science.gov (United States)

    All AB-type protein toxins have intracellular targets despite an initial extracellular location. These toxins use different methods to reach the cytosol and have different effects on the target cell. Broad-spectrum inhibitors against AB toxins are therefore hard to develop because the toxins use dif...

  19. Neutralising Antibodies against Ricin Toxin

    OpenAIRE

    Julie Prigent; Laetitia Panigai; Patricia Lamourette; Didier Sauvaire; Karine Devilliers; Marc Plaisance; Hervé Volland; Christophe Créminon; Stéphanie Simon

    2011-01-01

    The Centers for Disease Control and Prevention have listed the potential bioweapon ricin as a Category B Agent. Ricin is a so-called A/B toxin produced by plants and is one of the deadliest molecules known. It is easy to prepare and no curative treatment is available. An immunotherapeutic approach could be of interest to attenuate or neutralise the effects of the toxin. We sought to characterise neutralising monoclonal antibodies against ricin and to develop an effective therapy. For this pur...

  20. Toxin synergism in snake venoms

    DEFF Research Database (Denmark)

    Laustsen, Andreas Hougaard

    2016-01-01

    Synergism between venom toxins exists for a range of snake species. Synergism can be derived from both intermolecular interactions and supramolecular interactions between venom components, and can be the result of toxins targeting the same protein, biochemical pathway or physiological process. Few...... simple systematic tools and methods for determining the presence of synergism exist, but include co-administration of venom components and assessment of Accumulated Toxicity Scores. A better understanding of how to investigate synergism in snake venoms may help unravel strategies for developing novel...

  1. Toxin yet not toxic: Botulinum toxin in dentistry

    Directory of Open Access Journals (Sweden)

    Archana M.S.

    2016-04-01

    Full Text Available Paracelsus contrasted poisons from nonpoisons, stating that “All things are poisons, and there is nothing that is harmless; the dose alone decides that something is a poison”. Living organisms, such as plants, animals, and microorganisms, constitute a huge source of pharmaceutically useful medicines and toxins. Depending on their source, toxins can be categorized as phytotoxins, mycotoxins, or zootoxins, which include venoms and bacterial toxins. Any toxin can be harmful or beneficial. Within the last 100 years, the perception of botulinum neurotoxin (BTX has evolved from that of a poison to a versatile clinical agent with various uses. BTX plays a key role in the management of many orofacial and dental disorders. Its indications are rapidly expanding, with ongoing trials for further applications. However, despite its clinical use, what BTX specifically does in each condition is still not clear. The main aim of this review is to describe some of the unclear aspects of this potentially useful agent, with a focus on the current research in dentistry.

  2. Comparative in vitro and in vivo assessment of toxin neutralization by anti-tetanus toxin monoclonal antibodies

    Science.gov (United States)

    Yousefi, Mehdi; Khosravi-Eghbal, Roya; Reza Mahmoudi, Ahmad; Jeddi-Tehrani, Mahmood; Rabbani, Hodjatallah; Shokri, Fazel

    2014-01-01

    Tetanus is caused by the tetanus neurotoxin (TeNT), a 150 kDa single polypeptide molecule which is cleaved into an active two-chain molecule composed of a 50 kDa N-terminal light (L) and a 100 kDa C-terminal heavy (H) chains. Recently, extensive effort has focused on characterization of TeNT binding receptors and toxin neutralization by monoclonal antibodies (mAbs). Toxin binding inhibition and neutralization is routinely assessed either in vitro by the ganglioside GT1b binding inhibition assay or in vivo using an animal model. These two assay systems have never been compared. In the present study, we report characterization of eleven mAbs against different parts of TeNT. The toxin inhibitory and neutralization activity of the mAbs was assessed in vitro and in vivo respectively. Our data demonstrated that seven mAbs bind to fragment C of the heavy chain, two mAbs react with the light chain, one mAb recognizes both chains and one mAb reacts with neither light chain nor fragment C. Six fragment C specific mAbs were able to inhibit TeNT binding to GT1b ganglioside in vitro but three failed to neutralize the toxin in vivo. One in vitro inhibitory mAb (1F3E3) was found to synergize with the in vivo neutralizing mAbs to reduce toxin lethal activity in vivo. Sequencing of the immunoglobulin heavy and light chain variable region genes revealed that the three in vivo neutralizing mAbs were derived from a common origin. Altogether, our data suggests that fragment C specific mAbs contribute to toxin neutralization in both systems, though some of the GT1b binding inhibitory mAbs may not be able to neutralize TeNT in vivo. PMID:24126015

  3. Fibrinogenolytic toxin from Indian monocled cobra

    Indian Academy of Sciences (India)

    A fibrinogenolytic toxin of molecular weight 6.5 kDa has been purified from the venom of Indian monocled cobra (Naja kaouthia) by repeated cation exchange chromatography on CM-sephadex C-50. The purified toxin did not show any phospholipase activity but was mildly hemolytic on human erythrocytes. This toxin, called ...

  4. The frequency of molecular detection of virulence genes encoding cytolysin A, high-pathogenicity island and cytolethal distending toxin of Escherichia coli in cases of sudden infant death syndrome does not differ from that in other infant deaths and healthy infants.

    Science.gov (United States)

    Highet, Amanda R; Berry, Anne M; Bettelheim, Karl A; Goldwater, Paul N

    2009-03-01

    Consistent pathological findings in sudden infant death syndrome (SIDS) are seen which display similarities to the pathogenesis of toxaemic shock and/or sepsis. A key candidate infectious agent that is possibly involved is Escherichia coli, given its universal early colonization of the intestinal tract of infants and an increased frequency of toxigenic and mouse-lethal isolates from SIDS compared with comparison infants. An explanation for these findings has yet to be identified. Using PCR, we screened E. coli isolates from 145 SIDS and 101 dead control and healthy infants for three new candidate pathogenicity-related genes: clyA (cytolysin A), irp2 [high-pathogenicity island (HPI)-specific gene] and cdt (cytolethal distending toxin). The results failed to show a positive correlation with SIDS, instead proving that clyA and irp2 genes were common to the infant intestinal E. coli. Interestingly we observed a high rate of carriage of these two potentially pathogenic genes in E. coli from healthy infants in the absence of diarrhoeal disease, and we report that in a number of cases, the detection of HPI-specific genes was predictable by serotype. Despite the lack of associations defined so far, there remains the likelihood that genetic determinants influence the interactions between E. coli and the host, so these factors may be part of the multi-factorial aspect of SIDS.

  5. Alpha-Toxin Is Required for Biofilm Formation by Staphylococcus aureus

    OpenAIRE

    Caiazza, Nicky C.; O'Toole, G. A.

    2003-01-01

    Staphylococcus aureus is a common pathogen associated with nosocomial infections. It can persist in clinical settings and gain increased resistance to antimicrobial agents through biofilm formation. We have found that alpha-toxin, a secreted, multimeric, hemolytic toxin encoded by the hla gene, plays an integral role in biofilm formation. The hla mutant was unable to fully colonize plastic surfaces under both static and flow conditions. Based on microscopy studies, we propose that alpha-hemol...

  6. Magnetic properties of HoCoC2, HoNiC2 and their solid solutions

    Science.gov (United States)

    Michor, H.; Steiner, S.; Schumer, A.; Hembara, M.; Levytskyy, V.; Babizhetskyy, V.; Kotur, B.

    2017-11-01

    Magnetic properties of single crystalline HoCoC2 and the evolution of magnetic and structural features in a series of polycrystalline solid solutions HoCo1-xNixC2 (0 ⩽ x ⩽ 1) are investigated by means of X-ray diffraction, magnetization, magnetic susceptibility and specific heat measurements. The crystal structures of all investigated samples refers to the CeNiC2-type structure (space group Amm 2 and Pearson symbol oS8). Non-isoelectronic substitution of Co by Ni causes a non-linear increase of the unit cell volume and especially a non-monotonous variation of the a and c lattice parameters as well as a pronounced reduction of the C-C bond length of carbon dimers. Temperature dependent magnetization and specific heat measurements reveal a crossover from a ferromagnetic for HoCoC2 with TC = 10.6 (1) K to an antiferromagnetic ground state for HoNiC2 with TN = 2.78 (6) K and a non-monotonous variation of the magnetic ordering temperature with a minimum at intermediate compositions. Crystalline electric field effects of HoCoC2 and HoNiC2 are analysed using combined thermodynamic and magnetic susceptibility data. The electrical resistivity of HoNiC2 displays a distinct anomaly near room temperature which indicates the formation of a charge density wave (CDW) state as earlier reported for several other rare earth nickel dicarbides.

  7. Purification, crystallization and X-ray diffraction analysis of human synaptotagmin 1 C2A-C2B

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Miguel [Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437 (United States); Fuson, Kerry L. [Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437 (United States); Sutton, R. Bryan, E-mail: rbsutton@utmb.edu [Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437 (United States); Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0437 (United States); Robert, J. Justin [Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0437 (United States); Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437 (United States)

    2006-09-01

    Human synaptotagmin C2A-C2B has been expressed as a glutathione-S-transferase fusion protein in Escherichia coli. The purification, crystallization and preliminary X-ray analysis of this protein are reported here. Synaptotagmin acts as the Ca{sup 2+} sensor for neuronal exocytosis. The cytosolic domain of human synaptotagmin 1 is composed of tandem C2 domains: C2A and C2B. These C2 domains modulate the interaction of synaptotagmin with the phospholipid bilayer of the presynaptic terminus and effector proteins such as the SNARE complex. Human synaptotagmin C2A-C2B has been expressed as a glutathione-S-transferase fusion protein in Escherichia coli. The purification, crystallization and preliminary X-ray analysis of this protein are reported here. The crystals diffract to 2.7 Å and belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 82.37, b = 86.31, c = 140.2 Å. From self-rotation function analysis, there are two molecules in the asymmetric unit. The structure determination of the protein using this data is ongoing.

  8. Toxin content and cytotoxicity of algal dietary supplements

    Energy Technology Data Exchange (ETDEWEB)

    Heussner, A.H.; Mazija, L. [Human and Environmental Toxicology, University of Konstanz, 78457 Konstanz (Germany); Fastner, J. [Federal Environmental Agency, Section II 3.3—Drinking-water resources and treatment, Berlin (Germany); Dietrich, D.R., E-mail: daniel.dietrich@uni-konstanz.de [Human and Environmental Toxicology, University of Konstanz, 78457 Konstanz (Germany)

    2012-12-01

    Blue-green algae (Spirulina sp., Aphanizomenon flos-aquae) and Chlorella sp. are commercially distributed as organic algae dietary supplements. Cyanobacterial dietary products in particular have raised serious concerns, as they appeared to be contaminated with toxins e.g. microcystins (MCs) and consumers repeatedly reported adverse health effects following consumption of these products. The aim of this study was to determine the toxin contamination and the in vitro cytotoxicity of algae dietary supplement products marketed in Germany. In thirteen products consisting of Aph. flos-aquae, Spirulina and Chlorella or mixtures thereof, MCs, nodularins, saxitoxins, anatoxin-a and cylindrospermopsin were analyzed. Five products tested in an earlier market study were re-analyzed for comparison. Product samples were extracted and analyzed for cytotoxicity in A549 cells as well as for toxin levels by (1) phosphatase inhibition assay (PPIA), (2) Adda-ELISA and (3) LC–MS/MS. In addition, all samples were analyzed by PCR for the presence of the mcyE gene, a part of the microcystin and nodularin synthetase gene cluster. Only Aph. flos-aquae products were tested positive for MCs as well as the presence of mcyE. The contamination levels of the MC-positive samples were ≤ 1 μg MC-LR equivalents g{sup −1} dw. None of the other toxins were found in any of the products. However, extracts from all products were cytotoxic. In light of the findings, the distribution and commercial sale of Aph. flos-aquae products, whether pure or mixed formulations, for human consumption appear highly questionable. -- Highlights: ► Marketed algae dietary supplements were analyzed for toxins. ► Methods: Phosphatase inhibition assay (PPIA), Adda-ELISA, LC-MS/MS. ► Aph. flos-aquae products all tested positive for microcystins. ► Products tested negative for nodularins, saxitoxins, anatoxin-a, cylindrospermopsin. ► Extracts from all products were cytotoxic.

  9. Risk Assessment of Shellfish Toxins

    Directory of Open Access Journals (Sweden)

    Rex Munday

    2013-11-01

    Full Text Available Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved.

  10. Botulinum toxin for vaginismus treatment.

    Science.gov (United States)

    Ferreira, Juliana Rocha; Souza, Renan Pedra

    2012-01-01

    Vaginismus is characterized by recurrent or persistent involuntary contraction of the perineal muscles surrounding the outer third of the vagina when penile, finger, tampon, or speculum penetration is attempted. Recent results have suggested the use of botulinum toxin for the treatment of vaginismus. Here, we assessed previously published data to evaluate the therapeutic effectiveness of botulinum toxin for vaginismus. We have carried out a systematic review followed by a meta-analysis. Our results indicate that botulinum toxin is an effective therapeutic option for patients with vaginismus (pooled odds ratio of 8.723 with 95% confidence interval limits of 1.942 and 39.162, p = 0.005). This may hold particularly true in treatment-refractory patients because most of the studies included in this meta-analysis have enrolled these subjects in their primary analysis. Botulinum toxin appears to bea reasonable intervention for vaginismus. However, this conclusion should be read carefully because of the deficiency of placebo-controlled randomized clinical trials and the quality issues presented in the existing ones.

  11. Shigella Sonnei and Shiga Toxin

    Centers for Disease Control (CDC) Podcasts

    2016-07-28

    Katherine Lamba, an infectious disease epidemiologist with the California Department of Public Health, discusses Shiga Toxin producing Shigella sonnei.  Created: 7/28/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 7/28/2016.

  12. Genome-Wide Analysis of C2H2 Zinc-Finger Family Transcription Factors and Their Responses to Abiotic Stresses in Poplar (Populus trichocarpa)

    Science.gov (United States)

    Liu, Quangang; Wang, Zhanchao; Xu, Xuemei; Zhang, Haizhen; Li, Chenghao

    2015-01-01

    Background C2H2 zinc-finger (C2H2-ZF) proteins are a large gene family in plants that participate in various aspects of normal plant growth and development, as well as in biotic and abiotic stress responses. To date, no overall analysis incorporating evolutionary history and expression profiling of the C2H2-ZF gene family in model tree species poplar (Populus trichocarpa) has been reported. Principal Findings Here, we identified 109 full-length C2H2-ZF genes in P. trichocarpa, and classified them into four groups, based on phylogenetic analysis. The 109 C2H2-ZF genes were distributed unequally on 19 P. trichocarpa linkage groups (LGs), with 39 segmental duplication events, indicating that segmental duplication has been important in the expansion of the C2H2-ZF gene family. Promoter cis-element analysis indicated that most of the C2H2-ZF genes contain phytohormone or abiotic stress-related cis-elements. The expression patterns of C2H2-ZF genes, based on heatmap analysis, suggested that C2H2-ZF genes are involved in tissue and organ development, especially root and floral development. Expression analysis based on quantitative real-time reverse transcription polymerase chain reaction indicated that C2H2-ZF genes are significantly involved in drought, heat and salt response, possibly via different mechanisms. Conclusions This study provides a thorough overview of the P. trichocarpa C2H2-ZF gene family and presents a new perspective on the evolution of this gene family. In particular, some C2H2-ZF genes may be involved in environmental stress tolerance regulation. PtrZFP2, 19 and 95 showed high expression levels in leaves and/or roots under environmental stresses. Additionally, this study provided a solid foundation for studying the biological roles of C2H2-ZF genes in Populus growth and development. These results form the basis for further investigation of the roles of these candidate genes and for future genetic engineering and gene functional studies in Populus. PMID

  13. Genome-Wide Analysis of C2H2 Zinc-Finger Family Transcription Factors and Their Responses to Abiotic Stresses in Poplar (Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Quangang Liu

    Full Text Available C2H2 zinc-finger (C2H2-ZF proteins are a large gene family in plants that participate in various aspects of normal plant growth and development, as well as in biotic and abiotic stress responses. To date, no overall analysis incorporating evolutionary history and expression profiling of the C2H2-ZF gene family in model tree species poplar (Populus trichocarpa has been reported.Here, we identified 109 full-length C2H2-ZF genes in P. trichocarpa, and classified them into four groups, based on phylogenetic analysis. The 109 C2H2-ZF genes were distributed unequally on 19 P. trichocarpa linkage groups (LGs, with 39 segmental duplication events, indicating that segmental duplication has been important in the expansion of the C2H2-ZF gene family. Promoter cis-element analysis indicated that most of the C2H2-ZF genes contain phytohormone or abiotic stress-related cis-elements. The expression patterns of C2H2-ZF genes, based on heatmap analysis, suggested that C2H2-ZF genes are involved in tissue and organ development, especially root and floral development. Expression analysis based on quantitative real-time reverse transcription polymerase chain reaction indicated that C2H2-ZF genes are significantly involved in drought, heat and salt response, possibly via different mechanisms.This study provides a thorough overview of the P. trichocarpa C2H2-ZF gene family and presents a new perspective on the evolution of this gene family. In particular, some C2H2-ZF genes may be involved in environmental stress tolerance regulation. PtrZFP2, 19 and 95 showed high expression levels in leaves and/or roots under environmental stresses. Additionally, this study provided a solid foundation for studying the biological roles of C2H2-ZF genes in Populus growth and development. These results form the basis for further investigation of the roles of these candidate genes and for future genetic engineering and gene functional studies in Populus.

  14. Detection of vancomycin-resistant enterococci (VRE in stool specimens submitted for Clostridium difficile toxin testing

    Directory of Open Access Journals (Sweden)

    Sevim Özsoy

    Full Text Available Abstract The aim of this study was to determine the association between Clostridium difficile (C. difficile and vancomycin-resistant Enterococcus (VRE and efficacy of screening stools submitted for C. difficile toxin assay for prevalence of VRE. Between April 2012 and February 2014, 158 stool samples submitted for C. difficile toxin to the Marmara University Microbiology Laboratory, were included in the study. Stool samples were analyzed by enzyme immuno assay test; VIDAS (bioMerieux, France for Toxin A&B. Samples were inoculated on chromID VRE (bioMerieux, France and incubated 24 h at 37 °C. Manuel tests and API20 STREP (bioMerieux, France test were used to identify the Enterococci species. After the species identification, vancomycin and teicoplanin MIC's were performed by E test and molecular resistance genes for vanA vs vanB were detected by polymerase chain reaction (PCR. Of the 158 stool samples, 88 were toxin positive. The prevalence of VRE was 17%(n:19 in toxin positives however, 11.4% in toxin negatives(n:70. All VRE isolates were identified as Enterococcus faecium. These results were evaluated according to Fischer's exact chi-square test and p value between VRE colonization and C. difficile toxin positivity was detected 0.047 (p < 0.05. PPV and NPV were 79% and 47% respectively. In our study, the presence of VRE in C. difficile toxin positives is statistically significant compared with toxin negatives (p < 0.05. Screening for VRE is both additional cost and work load for the laboratories. Therefore VRE screening among C. difficile toxin positive samples, will be cost effective for determination of high risk patients in the hospitals especially for developing countries.

  15. C2 translaminar screw as the optimal choice for atlantoaxial dislocation with C2-C3 congenital fusion.

    Science.gov (United States)

    Zhou, Fengjin; Ni, Bin; Li, Songkai; Yang, Jian; Guo, Xiang; Zhu, Zhuangchen

    2010-12-01

    The entry point and trajectory are very important for transarticular screw (TAS) and C2 pedicle screw (PDS) plantation. When the physical size is not large enough for the screw passing through, an accurate entry point is the most important point for successful screw insertion without vertebral artery (VA) injury and spinal cord injury. Once the laminas of C2 and C3 are fused, the normal anatomic mark might disappear and the insertion point would be hard to find. As a result, the complication of TAS or PDS implantation increases rapidly. We used C2 translaminar screws (TLSs) with C1 lateral mass screws as the optimal fixation for atlantoaxial dislocation in order to reduce the risk of VA injury and spinal cord injury. A 37-year-old woman with atlantoaxial dislocation due to obsolete odontoid fracture complained of neck pain and myelopathy. Preoperative CT reconstruction showed C2-C3 fusion and small size of C2 isthmus. The patient underwent posterior atlantoaxial fusion using C1 lateral mass screws and C2 TLSs. The posterior arch of atlas was removed for decompression and fusion was done at C1-C2 joints by grafting bone fragments from the posterior iliac crest. TLSs combined with C1 lateral mass screws might be a useful technique for patients with atlantoaxial dislocation and C2-C3 fusion, especially with small size of C2 isthmus. Also, the fusion of posterior elements between C2 and C3 might be a relative contraindication for TAS fixation.

  16. Multicenter evaluation of the BD max enteric bacterial panel PCR assay for rapid detection of Salmonella spp., Shigella spp., Campylobacter spp. (C. jejuni and C. coli), and Shiga toxin 1 and 2 genes.

    Science.gov (United States)

    Harrington, S M; Buchan, B W; Doern, C; Fader, R; Ferraro, M J; Pillai, D R; Rychert, J; Doyle, L; Lainesse, A; Karchmer, T; Mortensen, J E

    2015-05-01

    Diarrhea due to enteric bacterial pathogens causes significant morbidity and mortality in the United States and worldwide. However, bacterial pathogens may be infrequently identified. Currently, culture and enzyme immunoassays (EIAs) are the primary methods used by clinical laboratories to detect enteric bacterial pathogens. We conducted a multicenter evaluation of the BD Max enteric bacterial panel (EBP) PCR assay in comparison to culture for the detection of Salmonella spp., Shigella spp., Campylobacter jejuni, and Campylobacter coli and an EIA for Shiga toxins 1 and 2. A total of 4,242 preserved or unpreserved stool specimens, including 3,457 specimens collected prospectively and 785 frozen, retrospective samples, were evaluated. Compared to culture or EIA, the positive percent agreement (PPA) and negative percent agreement (NPA) values for the BD Max EBP assay for all specimens combined were as follows: 97.1% and 99.2% for Salmonella spp., 99.1% and 99.7% for Shigella spp., 97.2% and 98.4% for C. jejuni and C. coli, and 97.4% and 99.3% for Shiga toxins, respectively. Discrepant results for prospective samples were resolved with alternate PCR assays and bidirectional sequencing of amplicons. Following discrepant analysis, PPA and NPA values were as follows: 97.3% and 99.8% for Salmonella spp., 99.2% and 100% for Shigella spp., 97.5% and 99.0% for C. jejuni and C. coli, and 100% and 99.7% for Shiga toxins, respectively. No differences in detection were observed for samples preserved in Cary-Blair medium and unpreserved samples. In this large, multicenter study, the BD Max EBP assay showed superior sensitivity compared to conventional methods and excellent specificity for the detection of enteric bacterial pathogens in stool specimens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Neuronal sensitivity to tetanus toxin requires gangliosides.

    Science.gov (United States)

    Williamson, L C; Bateman, K E; Clifford, J C; Neale, E A

    1999-08-27

    Tetanus toxin produces spastic paralysis in situ by blocking inhibitory neurotransmitter release in the spinal cord. Although di- and trisialogangliosides bind tetanus toxin, their role as productive toxin receptors remains unclear. We examined toxin binding and action in spinal cord cell cultures grown in the presence of fumonisin B(1), an inhibitor of ganglioside synthesis. Mouse spinal cord neurons grown for 3 weeks in culture in 20 microM fumonisin B(1) develop dendrites, axons, and synaptic terminals similar to untreated neurons, even though thin layer chromatography shows a greater than 90% inhibition of ganglioside synthesis. Absence of tetanus and cholera toxin binding by toxin-horseradish peroxidase conjugates or immunofluorescence further indicates loss of mono- and polysialogangliosides. In contrast to control cultures, tetanus toxin added to fumonisin B(1)-treated cultures does not block potassium-stimulated glycine release, inhibit activity-dependent uptake of FM1-43, or abolish immunoreactivity for vesicle-associated membrane protein, the toxin substrate. Supplementing fumonisin B(1)-treated cultures with mixed brain gangliosides completely restores the ability of tetanus toxin to bind to the neuronal surface and to block neurotransmitter release. These data demonstrate that fumonisin B(1) protects against toxin-induced synaptic blockade and that gangliosides are a necessary component of the receptor mechanism for tetanus toxin.

  18. C2 and C3 pain dermatomes in man.

    Science.gov (United States)

    Poletti, C E

    1991-07-01

    This report defines the C2 and C3 pain dermatomes by the distribution of: the hypalgesia clearing after surgical root decompression; the dysaesthesias produced by electrical root stimulation; and the hypalgesia produced by anaesthetic root block. The C2 pain dermatome, so defined, consists of an occipital parietal area 6-8 cm wide, ascending paramedially from the subocciput to the vertex. The C3 pain dermatome is a craniofacial area including the scalp around the ear, the pinna, the lateral cheek over the angle of the jaw, the submental region and the lateral and anterior aspects of the upper neck. These C2 and C3 pain dermatomes do not overlap and are smaller than the C2 and C3 tactile dermatomes described in the literature.

  19. Mechanism of Shiga Toxin Clustering on Membranes

    DEFF Research Database (Denmark)

    Pezeshkian, Weria; Gao, Haifei; Arumugam, Senthil

    2017-01-01

    The bacterial Shiga toxin interacts with its cellular receptor, the glycosphingolipid globotriaosylceramide (Gb3 or CD77), as a first step to entering target cells. Previous studies have shown that toxin molecules cluster on the plasma membrane, despite the apparent lack of direct interactions...... toxin molecules. By contrast, in coarse-grained computer simulations, a correlation was found between clustering and toxin nanoparticle-driven suppression of membrane fluctuations, and experimentally we observed that clustering required the toxin molecules to be tightly bound to the membrane surface....... The most likely interpretation of these findings is that a membrane fluctuation-induced force generates an effective attraction between toxin molecules. Such force would be of similar strength to the electrostatic force at separations around 1 nm, remain strong at distances up to the size of toxin...

  20. Terahertz Spectroscopy of the Bending Vibrations of Acetylene 12C2H2 and 12C2D2

    Science.gov (United States)

    Yu, Shanshan; Drouin, B.; Pearson, J.

    2009-12-01

    Several fundamental interstellar molecules, e.g., C2H2, CH4 and C3, are completely symmetric molecules and feature no permanent dipole moment and no pure rotation spectrum. As a result they have only previously been observed in the infrared. However, directly observing them with the rest of the molecular column especially when the source is spatially resolved would be very valuable in understanding chemical evolution. Vibrational difference bands provide a means to detect symmetric molecules with microwave precision using terahertz techniques. Herschel, SOFIA and ALMA have the potential to identify a number of vibrational difference bands of light symmetric species. This paper reports laboratory results on 12C2H2 and 12C2D2. Symmetric acetylene isotopologues have two bending modes, the trans bending and the cis bending. Their difference bands are allowed and occur in the microwave, terahertz, and far-infrared wavelengths, with band origins at 3500 GHz for 12C2H2 and 900 GHz for 12C2D2. Twenty 12C2H2 P branch high-J transitions and two hundred and fifty-one 12C2D2 P Q and R branch transitions have been measured in the 0.2 - 1.6 THz region with precision of 50 to 100 kHz. These lines were modeled together with prior data on the pure bending levels. Significantly improved molecular parameters were obtained for 12C2H2 and 12C2D2 with the combined data set, and new frequency and intensity predictions were made to support astrophysics applications. The research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. S. Y. was supported by an appointment to the NASA Postdoctoral Program, administrated by Oak Ridge Associated Universities through a contract with NASA.

  1. Organizational Change for Improved C2 in the Information Age

    Science.gov (United States)

    2006-10-23

    FINAL 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Organizational Change for Improved C2 in the Information Age 5a. CONTRACT NUMBER... Organizational Change for Improved C2 in the Information Age by Todd A. Beltz CDR USN A paper submitted to the Faculty of the Naval War...reiterated that a SJFHQ is an important step in increasing the ability to respond to… the global security environment.1 This organizational change is an

  2. Simulation Technologies for C2IS Development & Training

    Science.gov (United States)

    2008-02-01

    reels; ces demiers sont modifies (p. ex. fausses balles) ou augmentes (p. ex. equipement laser) afin de permettre Ie realisme sans encourir les risques...Simulation technologies for C2 information system (C2IS) development & training project was known as 12kr before 2003. Briefly designated 2kq when...split off from l2kr in fiscal year 200 1-2002 to become l2kx, which later became project l5al Geospatial technologies for information decisions (GEO

  3. C2 Rising: A Historical View of Our Critical Advantage

    Science.gov (United States)

    2014-08-01

    of six.11 In 1937 Tukhachevskii even conceptualized these C2 functions performed in the air, where a bird’s-eye view would offer maximum awareness to...terminology. • F1, orient shooters: increase shooter/sensor SA and threat warn- ing by providing SA. Battle management and ISR fusion tasks in this...this era seem to stumble upon the need for high-functioning C2 systems. Carrier war rooms, nuclear reactor control rooms, the National Military

  4. The Effect of Aerosols on Pluto's C2 Hydrocarbon Chemistry

    Science.gov (United States)

    Luspay-Kuti, Adrienn; Mandt, Kathleen; Jessup, Kandis-Lea; Hue, Vincent; Kammer, Joshua; Filwett, Rachael; Hamel, Mark

    2017-10-01

    On July 14, 2015 the New Horizons spacecraft flew through the Pluto system, providing critical details about Pluto’s atmosphere. The vertical profiles of N2 and CH4, C2H2, C2H4, and C2H6 derived from New Horizons Alice transmission data allow the more accurate modeling of Pluto’s atmosphere than in the pre-New Horizons era, and help better understand the physical and photochemical processes in Pluto’s atmosphere. All the measured C2 hydrocarbon densities showed an unexpected inversion between ~100 and 400 km, which suggests that processes other than chemistry play an important role in shaping their vertical profiles. We present here a state-of-the-art Pluto Ion-Neutral-Photochemistry (Pluto INP) model that includes the condensation onto and incorporation into aerosol particles, and evaluate the dominant production and loss processes of C2 hydrocarbons with a special emphasis on the role of aerosol interaction. We found that in order to reproduce the C2 profiles measured by New Horizons, they must stick to and be permanently removed by aerosols - a process different from condensation. We determined through empirical fits to the New Horizons data that the sticking efficiency of C2 hydrocarbons and the stickiness of the aerosol particles are inversely related to the available aerosol surface area, which has been inferred from observation to increase as altitude decreases. This counterintuitive relationship between sticking efficiency and available aerosol surfaces indicates that similarly to Titan, Pluto’s aerosols must harden and become less sticky as they age. Such hardening with ageing is both necessary and sufficient to explain the vertical profiles of C2 hydrocarbons in Pluto’s atmosphere.

  5. Standardization of the PCR technique for the detection of delta toxin in Staphylococcus spp.

    Directory of Open Access Journals (Sweden)

    C. Marconi

    2005-06-01

    Full Text Available Coagulase-negative staphylococci (CNS, components of the normal flora of neonates, have emerged as important opportunistic pathogens of nosocomial infections that occur in neonatal intensive care units. Some authors have reported the ability of some CNS strains, particularly Staphylococcus epidermidis, to produce a toxin similar to S. aureus delta toxin. This toxin is an exoprotein that has a detergent action on the membranes of various cell types resulting in rapid cell lysis. The objectives of the present study were to standardize the Polymerase Chain Reaction (PCR technique for the detection of the gene responsible for the production of delta toxin (hld gene in staphylococcal species isolated from catheters and blood cultures obtained from neonates, and to compare the results to those obtained with the phenotypic synergistic hemolysis method. Detection of delta toxin by the phenotypic and genotypic method yielded similar results for the S. aureus isolates. However, in S. epidermidis, a higher positivity was observed for PCR (97.4% compared to the synergistic hemolysis method (86.8%. Among CNS, S. epidermidis was the most frequent isolate and was a delta toxin producer. Staphylococcus simulans and S. warneri tested positive by the phenotypic method, but their positivity was not confirmed by PCR for the hld gene detection. These results indicate that different genes might be responsible for the production of this toxin in different CNS species, requiring highly specific primers for their detection. PCR was found to be a rapid and reliable method for the detection of the hld gene in S. aureus and S. epidermidis.

  6. Rare codons effect on expression of recombinant gene cassette in Escherichia coli BL21(DE3

    Directory of Open Access Journals (Sweden)

    Aghil Esmaeili-Bandboni

    2017-11-01

    Full Text Available Objective: To demonstrate the sensitivity of expression of fusion genes to existence of a large number of rare codons in recombinant gene sequenced. Methods: Primers for amplification of cholera toxin B, Shiga toxin B and gfp genes were designed by Primer3 software and synthesized. All of these 3 genes were cloned. Then the genes were fused together by restriction sites and enzymatic method. Two linkers were used as a flexible bridge in connection of these genes. Results: Cloning and fusion of cholera toxin B, Shiga toxin B and gfp genes were done correctly. After that, expression of the recombinant gene construction was surveyed. Conclusions: According to what was seen, because of the accumulation of 12 rare codons of Shiga toxin B and 19 rare codons of cholera toxin B in this gene cassette, the expression of the recombinant gene cassette, in Escherichia coli BL21, failed.

  7. DNA aptamers as a novel approach to neutralize Staphylococcus aureus α-toxin.

    Science.gov (United States)

    Vivekananda, Jeevalatha; Salgado, Christi; Millenbaugh, Nancy J

    2014-02-14

    Staphylococcus aureus is a versatile pathogen capable of causing a broad spectrum of diseases ranging from superficial skin infections to life threatening conditions such as endocarditis, septicemia, pneumonia and toxic shock syndrome. In vitro and in vivo studies identified an exotoxin, α-toxin, as a major cause of S. aureus toxicity. Because S. aureus has rapidly evolved resistance to a number of antibiotics, including methicillin, it is important to identify new therapeutic strategies, other than antibiotics, for inhibiting the harmful effects of this pathogen. Aptamers are single-stranded DNA or RNA oligonucleotides with three-dimensional folded conformations that bind with high affinity and selectivity to targets and modulate their biological functions. The goal of this study was to isolate DNA aptamers that specifically inhibit the cytotoxic activity of α-toxin. After 10 rounds of Systematic Evolution of Ligands by EXponential Enrichment (SELEX), 49 potential anti-α-toxin aptamers were identified. In vitro neutralization assays demonstrated that 4 of these 49 aptamers, AT-27, AT-33, AT-36, and AT-49, significantly inhibited α-toxin-mediated cell death in Jurkat T cells. Furthermore, RT-PCR analysis revealed that α-toxin increased the transcription of the inflammatory cytokines TNF-α and IL-17 and that anti-α-toxin aptamers AT-33 and AT-36 inhibited the upregulation of these genes. Collectively, the data suggest the feasibility of generating functionally effective aptamers against α-toxin for treatment of S. aureus infections. Published by Elsevier Inc.

  8. Coevolution takes the sting out of it: Evolutionary biology and mechanisms of toxin resistance in animals.

    Science.gov (United States)

    Arbuckle, Kevin; Rodríguez de la Vega, Ricardo C; Casewell, Nicholas R

    2017-10-27

    Understanding how biotic interactions shape the genomes of the interacting species is a long-sought goal of evolutionary biology that has been hampered by the scarcity of tractable systems in which specific genomic features can be linked to complex phenotypes involved in interspecific interactions. In this review we present the compelling case of evolved resistance to the toxic challenge of venomous or poisonous animals as one such system. Animal venoms and poisons can be comprised of few or of many individual toxins. Here we show that resistance to animal toxins has evolved multiple times across metazoans, although it has been documented more often in phyla that feed on chemically-armed animals than in prey of venomous predators. We review three types of gene-product based resistance: 1) toxin scavenging, where molecules produced by the envenomed organism bind and inactivate the toxins; 2) target-site insensitivity, including landmark cases of convergent changes that make the molecules normally targeted by animal toxins refractory, and; 3) off-target repurposing, where envenomed organisms overcome toxicity by exploiting the function of toxins to alter their physiological effect. We finish by discussing the evolutionary processes that likely played a role in the origin and maintenance of toxin resistance. We conclude that antagonistic interactions involving poisonous or venomous animals are unparalleled models for investigating microevolutionary processes involved in coevolution and linking them to macroevolutionary patterns. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A new Cry toxin with a unique two-component dependency from Bacillus sphaericus.

    Science.gov (United States)

    Jones, Gareth W; Nielsen-Leroux, Christina; Yang, Yankun; Yuan, Zhiming; Dumas, Vinícius Fiúza; Monnerat, Rose Gomes; Berry, Colin

    2007-12-01

    Highly pathogenic strains of Bacillus sphaericus produce the mosquitocidal Bin proteins, but resistance to this toxin can be produced under laboratory and field conditions. Analysis of strains able to overcome this resistance revealed the presence of a previously undescribed type of two-component toxin. One subunit, Cry48Aa1, is related to the 3-domain crystal toxins of Bacillus thuringiensis. Uniquely for this type of protein, insect toxicity is only achieved in the presence of a second, accessory protein, Cry49Aa1. This protein is itself related to both the binary toxin of B. sphaericus and to Cry35 and Cry36 of B. thuringiensis, none of which require interaction with Cry48Aa1-like proteins for their activity. The necessity for both Cry48Aa1 and Cry49Aa1 components for pathogenicity, therefore, indicates an unprecedented interaction to generate toxicity. Despite high potency for purified Cry48Aa1/Cry49Aa1 proteins (LC50 for third instar Culex quinquefasciatus larvae: 15.9 ng/ml and 6.3 ng/ml respectively), bacteria producing them show suboptimal mosquitocidal activity due to low-level Cry48Aa1 production. This new toxin combination may indicate a fortuitous combination of members of the gene families that encode 3-domain Cry toxins and Binary-like toxins, permitting the "mix-and-match" evolution of a new component in the mosquitocidal armoury.

  10. Anthrax toxin receptor 2-dependent lethal toxin killing in vivo.

    Directory of Open Access Journals (Sweden)

    Heather M Scobie

    2006-10-01

    Full Text Available Anthrax toxin receptors 1 and 2 (ANTXR1 and ANTXR2 have a related integrin-like inserted (I domain which interacts with a metal cation that is coordinated by residue D683 of the protective antigen (PA subunit of anthrax toxin. The receptor-bound metal ion and PA residue D683 are critical for ANTXR1-PA binding. Since PA can bind to ANTXR2 with reduced affinity in the absence of metal ions, we reasoned that D683 mutant forms of PA might specifically interact with ANTXR2. We show here that this is the case. The differential ability of ANTXR1 and ANTXR2 to bind D683 mutant PA proteins was mapped to nonconserved receptor residues at the binding interface with PA domain 2. Moreover, a D683K mutant form of PA that bound specifically to human and rat ANTXR2 mediated killing of rats by anthrax lethal toxin, providing strong evidence for the physiological importance of ANTXR2 in anthrax disease pathogenesis.

  11. Forkhead box C2 promoter variant c.-512C>T is associated with increased susceptibility to chronic venous diseases.

    Directory of Open Access Journals (Sweden)

    Sumi Surendran

    Full Text Available Chronic venous disease (CVD is one of the most prevalent yet underrated disorders worldwide. High heritability estimates of CVD indicate prominent genetic components in its etiology and pathology. Mutations in human forkhead box C2 (FoxC2 gene are strongly associated with valve failure in saphenous and deep veins of lower extremities. We explored the association of genetic variants of FoxC2 as well as FoxC2 mRNA and protein expression levels with CVD of lower limbs. We systematically sequenced the single coding exon, 5' and 3' flanking regions of FoxC2 gene in 754 study subjects which includes 382 patients with CVD and 372 healthy subjects. Four novel and three reported polymorphisms were identified in our cohort. Three variants in 5' flanking region and one in 3' flanking region of FoxC2 gene were significantly associated with CVD risk. FoxC2 mRNA in vein tissues from 22 patients was 4±1.42 fold increased compared to saphenous veins from 20 normal subjects (pT (rs34221221: C>T variant which is located in the FoxC2 putative promoter region was further analyzed. Functional analysis of c.-512C>T revealed increased mRNA and protein expression in patients with homozygous TT genotype compared to heterozygous CT and wild CC genotypes. Luciferase assay indicated higher transcriptional activity of mutant compared to wild genotype of this variant. These findings suggested that c.-512C>T variant of FoxC2 was strongly associated with susceptibility to CVD and also that this variant resulted in FoxC2 overexpression. To obtain a mechanistic insight into the role of upregulated FoxC2 in varicosities, we overexpressed FoxC2 in venous endothelial cells and observed elevated expression of arterial markers Dll4 and Hey2 and downregulation of venous marker COUP-TFII. Our study indicates altered FoxC2-Notch signaling in saphenous vein wall remodeling in patients with varicose veins.

  12. A generalized stoichiometric model of C3, C2, C2+C4, and C4 photosynthetic metabolism.

    OpenAIRE

    Bellasio, C.

    2016-01-01

    The goal of suppressing photorespiration in crops to maximize assimilation and yield is stimulating considerable interest among researchers looking to bioengineer carbon-concentrating mechanisms into C3 plants. However, detailed quantification of the biochemical activities in the bundle sheath is lacking. This work presents a general stoichiometric model for C3, C2, C2+C4, and C4 assimilation (SMA) in which energetics, metabolite traffic, and the different decarboxylating enzymes (NAD-depende...

  13. Two distinct RNase activities of CRISPR-C2c2 enable guide-RNA processing and RNA detection.

    Science.gov (United States)

    East-Seletsky, Alexandra; O'Connell, Mitchell R; Knight, Spencer C; Burstein, David; Cate, Jamie H D; Tjian, Robert; Doudna, Jennifer A

    2016-10-13

    Bacterial adaptive immune systems use CRISPRs (clustered regularly interspaced short palindromic repeats) and CRISPR-associated (Cas) proteins for RNA-guided nucleic acid cleavage. Although most prokaryotic adaptive immune systems generally target DNA substrates, type III and VI CRISPR systems direct interference complexes against single-stranded RNA substrates. In type VI systems, the single-subunit C2c2 protein functions as an RNA-guided RNA endonuclease (RNase). How this enzyme acquires mature CRISPR RNAs (crRNAs) that are essential for immune surveillance and how it carries out crRNA-mediated RNA cleavage remain unclear. Here we show that bacterial C2c2 possesses a unique RNase activity responsible for CRISPR RNA maturation that is distinct from its RNA-activated single-stranded RNA degradation activity. These dual RNase functions are chemically and mechanistically different from each other and from the crRNA-processing behaviour of the evolutionarily unrelated CRISPR enzyme Cpf1 (ref. 11). The two RNase activities of C2c2 enable multiplexed processing and loading of guide RNAs that in turn allow sensitive detection of cellular transcripts.

  14. A generalized stoichiometric model of C3, C2, C2+C4, and C4 photosynthetic metabolism.

    Science.gov (United States)

    Bellasio, Chandra

    2017-01-01

    The goal of suppressing photorespiration in crops to maximize assimilation and yield is stimulating considerable interest among researchers looking to bioengineer carbon-concentrating mechanisms into C3 plants. However, detailed quantification of the biochemical activities in the bundle sheath is lacking. This work presents a general stoichiometric model for C3, C2, C2+C4, and C4 assimilation (SMA) in which energetics, metabolite traffic, and the different decarboxylating enzymes (NAD-dependent malic enzyme, NADP-dependent malic enzyme, or phosphoenolpyruvate carboxykinase) are explicitly included. The SMA can be used to refine experimental data analysis or formulate hypothetical scenarios, and is coded in a freely available Microsoft Excel workbook. The theoretical underpinnings and general model behaviour are analysed with a range of simulations, including (i) an analysis of C3, C2, C2+C4, and C4 in operational conditions; (ii) manipulating photorespiration in a C3 plant; (iii) progressively upregulating a C2 shuttle in C3 photosynthesis; (iv) progressively upregulating a C4 cycle in C2 photosynthesis; and (v) manipulating processes that are hypothesized to respond to transient environmental inputs. Results quantify the functional trade-offs, such as the electron transport needed to meet ATP/NADPH demand, as well as metabolite traffic, inherent to different subtypes. The SMA refines our understanding of the stoichiometry of photosynthesis, which is of paramount importance for basic and applied research. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. The upgrade of the Thomson scattering system for measurement on the C-2/C-2U devices

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, K.; Schindler, T.; Kinley, J.; Deng, B.; Thompson, M. C. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)

    2016-11-15

    The C-2/C-2U Thomson scattering system has been substantially upgraded during the latter phase of C-2/C-2U program. A Rayleigh channel has been added to each of the three polychromators of the C-2/C-2U Thomson scattering system. Onsite spectral calibration has been applied to avoid the issue of different channel responses at different spots on the photomultiplier tube surface. With the added Rayleigh channel, the absolute intensity response of the system is calibrated with Rayleigh scattering in argon gas from 0.1 to 4 Torr, where the Rayleigh scattering signal is comparable to the Thomson scattering signal at electron densities from 1 × 10{sup 13} to 4 × 10{sup 14} cm{sup −3}. A new signal processing algorithm, using a maximum likelihood method and including detailed analysis of different noise contributions within the system, has been developed to obtain electron temperature and density profiles. The system setup, spectral and intensity calibration procedure and its outcome, data analysis, and the results of electron temperature/density profile measurements will be presented.

  16. Diversity and impact of prokaryotic toxins on aquatic environments: a review.

    Science.gov (United States)

    Valério, Elisabete; Chaves, Sandra; Tenreiro, Rogério

    2010-10-01

    . Clostridium members are also spore-forming bacteria and can persist in hostile environmental conditions for long periods of time, contributing to their hazard grade. Similarly, Pseudomonas species are widespread in the environment. Since P. aeruginosa is an emergent opportunistic pathogen, its toxins may represent new hazards for humans and animals. This review presents an overview of the diversity of toxins produced by prokaryotic microorganisms associated with aquatic habitats and their impact on environment, life and health of humans and other animals. Moreover, important issues like the availability of these toxins in the environment, contamination sources and pathways, genes involved in their biosynthesis and molecular mechanisms of some representative toxins are also discussed.

  17. Diversity and Impact of Prokaryotic Toxins on Aquatic Environments: A Review

    Directory of Open Access Journals (Sweden)

    Rogério Tenreiro

    2010-10-01

    and irrigation water. Clostridium members are also spore-forming bacteria and can persist in hostile environmental conditions for long periods of time, contributing to their hazard grade. Similarly, Pseudomonas species are widespread in the environment. Since P. aeruginosa is an emergent opportunistic pathogen, its toxins may represent new hazards for humans and animals. This review presents an overview of the diversity of toxins produced by prokaryotic microorganisms associated with aquatic habitats and their impact on environment, life and health of humans and other animals. Moreover, important issues like the availability of these toxins in the environment, contamination sources and pathways, genes involved in their biosynthesis and molecular mechanisms of some representative toxins are also discussed.

  18. Why do we study animal toxins?

    Science.gov (United States)

    ZHANG, Yun

    2015-01-01

    Venom (toxins) is an important trait evolved along the evolutionary tree of animals. Our knowledges on venoms, such as their origins and loss, the biological relevance and the coevolutionary patterns with other organisms are greatly helpful in understanding many fundamental biological questions, i.e., the environmental adaptation and survival competition, the evolution shaped development and balance of venoms, and the sophisticated correlations among venom, immunity, body power, intelligence, their genetic basis, inherent association, as well as the cost-benefit and trade-offs of biological economy. Lethal animal envenomation can be found worldwide. However, from foe to friend, toxin studies have led lots of important discoveries and exciting avenues in deciphering and fighting human diseases, including the works awarded the Nobel Prize and lots of key clinic therapeutics. According to our survey, so far, only less than 0.1% of the toxins of the venomous animals in China have been explored. We emphasize on the similarities shared by venom and immune systems, as well as the studies of toxin knowledge-based physiological toxin-like proteins/peptides (TLPs). We propose the natural pairing hypothesis. Evolution links toxins with humans. Our mission is to find out the right natural pairings and interactions of our body elements with toxins, and with endogenous toxin-like molecules. Although, in nature, toxins may endanger human lives, but from a philosophical point of view, knowing them well is an effective way to better understand ourselves. So, this is why we study toxins. PMID:26228472

  19. Exfoliative Toxins of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Michal Bukowski

    2010-05-01

    Full Text Available Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These include toxic shock syndrome toxin 1 (TSST-1, enterotoxins, and exfoliative toxins (ETs. The latter are particularly interesting as the sole agents responsible for staphylococcal scalded skin syndrome (SSSS, a disease predominantly affecting infants and characterized by the loss of superficial skin layers, dehydration, and secondary infections. The molecular basis of the clinical symptoms of SSSS is well understood. ETs are serine proteases with high substrate specificity, which selectively recognize and hydrolyze desmosomal proteins in the skin. The fascinating road leading to the discovery of ETs as the agents responsible for SSSS and the characterization of the molecular mechanism of their action, including recent advances in the field, are reviewed in this article.

  20. Regulating Toxin-Antitoxin Expression: Controlled Detonation of Intracellular Molecular Timebombs

    Directory of Open Access Journals (Sweden)

    Finbarr Hayes

    2014-01-01

    Full Text Available Genes for toxin-antitoxin (TA complexes are widely disseminated in bacteria, including in pathogenic and antibiotic resistant species. The toxins are liberated from association with the cognate antitoxins by certain physiological triggers to impair vital cellular functions. TAs also are implicated in antibiotic persistence, biofilm formation, and bacteriophage resistance. Among the ever increasing number of TA modules that have been identified, the most numerous are complexes in which both toxin and antitoxin are proteins. Transcriptional autoregulation of the operons encoding these complexes is key to ensuring balanced TA production and to prevent inadvertent toxin release. Control typically is exerted by binding of the antitoxin to regulatory sequences upstream of the operons. The toxin protein commonly works as a transcriptional corepressor that remodels and stabilizes the antitoxin. However, there are notable exceptions to this paradigm. Moreover, it is becoming clear that TA complexes often form one strand in an interconnected web of stress responses suggesting that their transcriptional regulation may prove to be more intricate than currently understood. Furthermore, interference with TA gene transcriptional autoregulation holds considerable promise as a novel antibacterial strategy: artificial release of the toxin factor using designer drugs is a potential approach to induce bacterial suicide from within.

  1. Botulinum toxin: mechanisms of action

    OpenAIRE

    Dirk Dressler; Fereshte Adib Saberi; Egberto Reis Barbosa

    2005-01-01

    This review describes therapeutically relevant mechanisms of action of botulinum toxin (BT). BT's molecular mode of action includes extracellular binding to glycoproteine structures on cholinergic nerve terminals and intracellular blockade of the acetylcholine secretion. BT affects the spinal stretch reflex by blockade of intrafusal muscle fibres with consecutive reduction of Ia/II afferent signals and muscle tone without affecting muscle strength (reflex inhibition). This mechanism allows fo...

  2. Positive Darwinian selection results in resistance to cardioactive toxins in true toads (Anura: Bufonidae).

    Science.gov (United States)

    Moore, David J; Halliday, Damien C T; Rowell, David M; Robinson, Anthony J; Keogh, J Scott

    2009-08-23

    Members of the Family Bufonidae, true toads, are famous for their endogenously synthesized cardioactive steroids that serve as defensive toxins. Evolution of resistance to these toxins is not understood. We sequenced a key region of the toxin's binding site in the Na(+)/K(+) ATPase for relevant taxa representing Hyloidea (including bufonids), Ranoidea and Archaeobatrachia and tested for positive selection in a phylogenetic context. Bufonidae were distinct from other Hyloidea at 4-6 of 12 sites and, with one exception, had a homologous amino acid sequence. Melanophryniscus stelzneri had a distinct sequence, consistent with other independent evidence for a differentiated toxin. Tests within Bufonidae detected positive selection within the binding region, providing, to our knowledge, the first evidence of this type for positive selection within Amphibia. There was no evidence for positive selection on Bufonidae or M. stelzneri lineages. Sequence change in Leptodactylus ocellatus, a leptodactylid predator of Bufonidae, provides a molecular basis for predator resistance possibly associated with gene duplication.

  3. Neutralising Antibodies against Ricin Toxin

    Science.gov (United States)

    Prigent, Julie; Panigai, Laetitia; Lamourette, Patricia; Sauvaire, Didier; Devilliers, Karine; Plaisance, Marc; Volland, Hervé; Créminon, Christophe; Simon, Stéphanie

    2011-01-01

    The Centers for Disease Control and Prevention have listed the potential bioweapon ricin as a Category B Agent. Ricin is a so-called A/B toxin produced by plants and is one of the deadliest molecules known. It is easy to prepare and no curative treatment is available. An immunotherapeutic approach could be of interest to attenuate or neutralise the effects of the toxin. We sought to characterise neutralising monoclonal antibodies against ricin and to develop an effective therapy. For this purpose, mouse monoclonal antibodies (mAbs) were produced against the two chains of ricin toxin (RTA and RTB). Seven mAbs were selected for their capacity to neutralise the cytotoxic effects of ricin in vitro. Three of these, two anti-RTB (RB34 and RB37) and one anti-RTA (RA36), when used in combination improved neutralising capacity in vitro with an IC50 of 31 ng/ml. Passive administration of association of these three mixed mAbs (4.7 µg) protected mice from intranasal challenges with ricin (5 LD50). Among those three antibodies, anti-RTB antibodies protected mice more efficiently than the anti-RTA antibody. The combination of the three antibodies protected mice up to 7.5 hours after ricin challenge. The strong in vivo neutralising capacity of this three mAbs combination makes it potentially useful for immunotherapeutic purposes in the case of ricin poisoning or possibly for prevention. PMID:21633505

  4. Neutralising antibodies against ricin toxin.

    Directory of Open Access Journals (Sweden)

    Julie Prigent

    Full Text Available The Centers for Disease Control and Prevention have listed the potential bioweapon ricin as a Category B Agent. Ricin is a so-called A/B toxin produced by plants and is one of the deadliest molecules known. It is easy to prepare and no curative treatment is available. An immunotherapeutic approach could be of interest to attenuate or neutralise the effects of the toxin. We sought to characterise neutralising monoclonal antibodies against ricin and to develop an effective therapy. For this purpose, mouse monoclonal antibodies (mAbs were produced against the two chains of ricin toxin (RTA and RTB. Seven mAbs were selected for their capacity to neutralise the cytotoxic effects of ricin in vitro. Three of these, two anti-RTB (RB34 and RB37 and one anti-RTA (RA36, when used in combination improved neutralising capacity in vitro with an IC(50 of 31 ng/ml. Passive administration of association of these three mixed mAbs (4.7 µg protected mice from intranasal challenges with ricin (5 LD(50. Among those three antibodies, anti-RTB antibodies protected mice more efficiently than the anti-RTA antibody. The combination of the three antibodies protected mice up to 7.5 hours after ricin challenge. The strong in vivo neutralising capacity of this three mAbs combination makes it potentially useful for immunotherapeutic purposes in the case of ricin poisoning or possibly for prevention.

  5. Paralytic shellfish toxins inhibit copper uptake in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Cusick, Kathleen D; Wetzel, Randall K; Minkin, Steven C; Dodani, Sheel C; Wilhelm, Steven W; Sayler, Gary S

    2013-06-01

    Paralytic shellfish toxins are secondary metabolites produced by several species of dinoflagellates and cyanobacteria. Known targets of these toxins, which typically occur at detrimental concentrations during harmful algal blooms, include voltage-gated ion channels in humans and other mammals. However, the effects of the toxins on the co-occurring phytoplankton community remain unknown. The present study examined the molecular mechanisms of the model photosynthetic alga Chlamydomonas reinhardtii in response to saxitoxin exposure as a means of gaining insight into the phytoplankton community response to a bloom. Previous work with yeast indicated that saxitoxin inhibited copper uptake, so experiments were designed to examine whether saxitoxin exhibited a similar mode of action in algae. Expression profiling following exposure to saxitoxin or a copper chelator produced similar profiles in copper homeostasis genes, notably induction of the cytochrome c6 (CYC6) and copper transporter (COPT1, CTR1) genes. Cytochrome c6 is used as an alternative to plastocyanin under conditions of copper deficiency, and immunofluorescence data showed this protein to be present in a significantly greater proportion of saxitoxin-exposed cells compared to controls. Live-cell imaging with a copper-sensor probe for intracellular labile Cu(I) confirmed that saxitoxin blocked copper uptake. Extrapolations of these data to phytoplankton metabolic processes along with the copper transporter as a molecular target of saxitoxin based on existing structural models are discussed. Copyright © 2013 SETAC.

  6. Detection of E. coli O157:H7 and Shigella dysenteriae toxins in clinical samples by PCR-ELISA

    Directory of Open Access Journals (Sweden)

    Jafar Amani

    Full Text Available Shiga toxin producing bacteria are potential causes of serious human disease such as hemorrhagic colitis, severe inflammations of ileocolonic regions of gastrointestinal tract, thrombocytopenia, septicemia, malignant disorders in urinary ducts, hemolytic uremic syndrome (HUS Shiga toxin 1 (stx1, shiga toxin 2 (stx2, or a combination of both are responsible for most clinical symptoms of these diseases. A lot of methods have been developed so far to detect shiga toxins such as cell culture, ELISA, and RFPLA, but due to high costs and labor time in addition to low sensitivity, they have not received much attention. In this study, PCR-ELISA method was used to detect genes encoding shiga toxins 1 and 2 (stx1 and stx2. To detect stx1 and stx2 genes, two primer pairs were designed for Multiplex-PCR then PCR-ELISA. PCR products (490 and 275, respectively were subsequently verified by sequencing. Sensitivity and specificity of PCR-ELISA method were determined by using genome serial dilution and Enterobacteriastrains. PCR-ELISA method used in this study proved to be a rapid and precise approach to detect different types of shiga toxins and can be used to detect bacterial genes encoding shiga toxins.

  7. Detection of E. coli O157:H7 and Shigella dysenteriae toxins in clinical samples by PCR-ELISA.

    Science.gov (United States)

    Amani, Jafar; Ahmadpour, Askary; Imani Fooladi, Abbas Ali; Nazarian, Shahram

    2015-01-01

    Shiga toxin producing bacteria are potential causes of serious human disease such as hemorrhagic colitis, severe inflammations of ileocolonic regions of gastrointestinal tract, thrombocytopenia, septicemia, malignant disorders in urinary ducts, hemolytic uremic syndrome (HUS). Shiga toxin 1 (stx1), shiga toxin 2 (stx2), or a combination of both are responsible for most clinical symptoms of these diseases. A lot of methods have been developed so far to detect shiga toxins such as cell culture, ELISA, and RFPLA, but due to high costs and labor time in addition to low sensitivity, they have not received much attention. In this study, PCR-ELISA method was used to detect genes encoding shiga toxins1 and 2 (stx1 and stx2). To detect stx1 and stx2 genes, two primer pairs were designed for Multiplex-PCR then PCR-ELISA. PCR products (490 and 275, respectively) were subsequently verified by sequencing. Sensitivity and specificity of PCR-ELISA method were determined by using genome serial dilution and Enterobacteria strains. PCR-ELISA method used in this study proved to be a rapid and precise approach to detect different types of shiga toxins and can be used to detect bacterial genes encoding shiga toxins. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  8. Detection of E. coli O157:H7 and Shigella dysenteriae toxins in clinical samples by PCR-ELISA

    Directory of Open Access Journals (Sweden)

    Jafar Amani

    2015-05-01

    Full Text Available Shiga toxin producing bacteria are potential causes of serious human disease such as hemorrhagic colitis, severe inflammations of ileocolonic regions of gastrointestinal tract, thrombocytopenia, septicemia, malignant disorders in urinary ducts, hemolytic uremic syndrome (HUS. Shiga toxin 1 (stx1, shiga toxin 2 (stx2, or a combination of both are responsible for most clinical symptoms of these diseases. A lot of methods have been developed so far to detect shiga toxins such as cell culture, ELISA, and RFPLA, but due to high costs and labor time in addition to low sensitivity, they have not received much attention. In this study, PCR-ELISA method was used to detect genes encoding shiga toxins1 and 2 (stx1 and stx2. To detect stx1 and stx2 genes, two primer pairs were designed for Multiplex-PCR then PCR-ELISA. PCR products (490 and 275, respectively were subsequently verified by sequencing. Sensitivity and specificity of PCR-ELISA method were determined by using genome serial dilution and Enterobacteria strains. PCR-ELISA method used in this study proved to be a rapid and precise approach to detect different types of shiga toxins and can be used to detect bacterial genes encoding shiga toxins.

  9. Toxin-Induced and Genetic Animal Models of Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Shin Hisahara

    2011-01-01

    Full Text Available Parkinson's disease (PD is a common progressive neurodegenerative disorder. The major pathological hallmarks of PD are the selective loss of nigrostriatal dopaminergic neurons and the presence of intraneuronal aggregates termed Lewy bodies (LBs, but the pathophysiological mechanisms are not fully understood. Epidemiologically, environmental neurotoxins such as pesticides are promising candidates for causative factors of PD. Oxidative stress and mitochondrial dysfunction induced by these toxins could contribute to the progression of PD. While most cases of PD are sporadic, specific mutations in genes that cause familial forms of PD have led to provide new insights into its pathogenesis. This paper focuses on animal models of both toxin-induced and genetically determined PD that have provided significant insight for understanding this disease. We also discuss the validity, benefits, and limitations of representative models.

  10. Curriculum for EPS Hockey E2-C2-juniors

    OpenAIRE

    Heinonen, Aleksi

    2017-01-01

    Coaching in hockey has changed in direction from coach-centered coaching to player-centered coaching. Nowadays it is more holistic; it is not just coaching tactics and trying to win games at all costs. The way of thinking has changed; instead of the former “what does a team need” way of thinking, nowadays it is more important to ask, “What does an individual need?” This thesis has been written for EPS Hockey E2-C2 juniors and E2-C2 coaches. The Executive Manager of EPS Hockey requested...

  11. Global mitotic phosphorylation of C2H2 zinc finger protein linker peptides.

    Science.gov (United States)

    Rizkallah, Raed; Alexander, Karen E; Hurt, Myra M

    2011-10-01

    Cessation of transcriptional activity is a hallmark of cell division. Many biochemical pathways have been shown and proposed over the past few decades to explain the silence of this phase. In particular, many individual transcription factors have been shown to be inactivated by phosphorylation. In this report, we show the simultaneous phosphorylation and mitotic redistribution of a whole class of modified transcription factors. C(2)H(2) zinc finger proteins (ZFPs) represent the largest group of gene expression regulators in the human genome. Despite their diversity, C(2)H(2) ZFPs display striking conservation of small linker peptides joining their adjacent zinc finger modules. These linkers are critical for DNA binding activity. It has been proposed that conserved phosphorylation of these linker peptides could be a common mechanism for the inactivation of the DNA binding activity of C(2)H(2) ZFPs, during mitosis. Using a novel antibody, raised against the phosphorylated form of the most conserved linker peptide sequence, we are able to visualize the massive and simultaneous mitotic phosphorylation of hundreds of these proteins. We show that this wave of phosphorylation is tightly synchronized, starting in mid-prophase right after DNA condensation and before the breakdown of the nuclear envelope. This global phosphorylation is completely reversed in telophase. In addition, the exclusion of the phospho-linker signal from condensed DNA clearly demonstrates a common mechanism for the mitotic inactivation of C(2)H(2) ZFPs. © 2011 Landes Bioscience

  12. BAMBI Promotes C2C12 Myogenic Differentiation by Enhancing Wnt/β-Catenin Signaling

    Directory of Open Access Journals (Sweden)

    Qiangling Zhang

    2015-08-01

    Full Text Available Bone morphogenic protein and activin membrane-bound inhibitor (BAMBI is regarded as an essential regulator of cell proliferation and differentiation that represses transforming growth factor-β and enhances Wnt/β-catenin signaling in various cell types. However, its role in skeletal muscle remains largely unknown. In the current study, we found that the expression level of BAMBI peaked in the early differentiation phase of the C2C12 rodent myoblast cell line. Knockdown of BAMBI via siRNA inhibited C2C12 differentiation, indicated by repressed MyoD, MyoG, and MyHC expression as well as reductions in the differentiation and fusion indices. BAMBI knockdown reduced the activity of Wnt/β-catenin signaling, as characterized by the decreased nuclear translocation of β-catenin and the lowered transcription of Axin2, which is a well-documented target gene of the Wnt/β-catenin signaling pathway. Furthermore, treatment with LiCl, an activator of Wnt/β-catenin signaling, rescued the reduction in C2C12 differentiation caused by BAMBI siRNA. Taken together, our data suggest that BAMBI is required for normal C2C12 differentiation, and that its role in myogenesis is mediated by the Wnt/β-catenin pathway.

  13. Bioluminescent bioreporter sensing of foodborne toxins

    Science.gov (United States)

    Fraley, Amanda C.; Ripp, Steven; Sayler, Gary S.

    2004-06-01

    Histamine is the primary etiological agent in the foodborne disease scombrotoxicosis, one of the most common food toxicities related to fish consumption. Procedures for detecting histamine in fish products are available, but are often too expensive or too complex for routine use. As an alternative, a bacterial bioluminescent bioreporter has been constructed to develop a biosensor system that autonomously responds to low levels of histamine. The bioreporter contains a promoterless Photorhabdus luminescens lux operon (luxCDABE) fused with the Vibrio anguillarum angR regulatory gene promoter of the anguibactin biosynthetic operon. The bioreporter emitted 1.46 times more bioluminescence than background, 30 minutes after the addition of 100mM histamine. However, specificity was not optimal, as this biosensor generated significant bioluminescence in the presence of L-proline and L-histidine. As a means towards improving histamine specificity, the promoter region of a histamine oxidase gene from Arthrobacter globiformis was cloned upstream of the promotorless lux operon from Photorhabdus luminescens. This recently constructed whole-cell, lux-based bioluminescent bioreporter is currently being tested for optimal performance in the presence of histamine in order to provide a rapid, simple, and inexpensive model sensor for the detection of foodborne toxins.

  14. Targeting the latent cytomegalovirus reservoir with an antiviral fusion toxin protein

    DEFF Research Database (Denmark)

    Krishna, B A; Spiess, K; Poole, E L

    2017-01-01

    latency, and one viral gene expressed by latently infected myeloid cells is US28. This viral gene encodes a cell surface G protein-coupled receptor (GPCR) that binds chemokines, triggering its endocytosis. We show that the expression of US28 on the surface of latently infected cells allows monocytes...... and their progenitor CD34+ cells to be targeted and killed by F49A-FTP, a highly specific fusion toxin protein that binds this viral GPCR. As expected, this specific targeting of latently infected cells by F49A-FTP also robustly reduces virus reactivation in vitro. Consequently, such specific fusion toxin proteins...

  15. Relevance of Bt toxin interaction studies for environmental risk assessment of genetically modified crops.

    Science.gov (United States)

    De Schrijver, Adinda; De Clercq, Patrick; de Maagd, Ruud A; van Frankenhuyzen, Kees

    2015-12-01

    In recent years, different Bacillus thuringiensis (Bt) toxin-encoding genes have been combined or 'stacked' in genetically modified (GM) crops. Synergism between Bt proteins may occur and thereby increase the impact of the stacked GM event on nontarget invertebrates compared to plants expressing a single Bt gene. On the basis of bioassay data available for Bt toxins alone or in combination, we argue that the current knowledge of Bt protein interactions is of limited relevance in environmental risk assessment (ERA). © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  16. Natural toxins and their therapeutic potential.

    Science.gov (United States)

    Kapoor, V K

    2010-03-01

    Plants have been extensively investigated for exploring their therapeutic potentials, but there are comparatively scanty reports on drugs derived from animal kingdom, except for hormones. During last decade, the toxins that are used for defense by the animals, have been isolated and found useful tools for physiological and pharmacological studies, besides giving valuable leads to drug development. Toxins with interesting results have been isolated from the venoms of snakes, scorpions, spiders, snails, lizards, frogs and fish. The present review describe about some toxins as drugs and their biological activities. Some fungal, bacterial and marine toxins have also been covered in this article.

  17. TvZNF1 is a C2H2 zinc finger protein of Trichomonas vaginalis.

    Science.gov (United States)

    Villalpando, José Luis; Arreola, Rodrigo; Puente-Rivera, Jonathan; Azuara-Liceaga, Elisa; Valdés, Jesús; López-Canovas, Lilia; Villalobos-Osnaya, Alma; Alvarez-Sánchez, Maria Elizbeth

    2017-12-01

    The zinc fingers proteins (ZNF) are the largest family of DNA binding proteins and can act as transcriptional factors in eukaryotes. ZNF are implicated in activation in response to environmental stimulus by biometals such as Zn2+. Many of these proteins have the classical C2H2 zinc finger motifs (C2H2-ZNFm) of approximately 30 amino acids, where a Zn2+ ion is coordinated by two cysteine and two histidine residues. Trichomonas vaginalis is a protozoan parasite than responds to environmental changes including Zn2+. Until now has not been described any ZNF that could be involved in the regulation of genic expression of T. vaginalis. Here, we characterized in silico and experimentally an annoted ZNF (TvZNF1) from T. vaginalis and isolated the gene, tvznf1 encoding it. TvZNF1 have eight C2H2-ZNFm with residues that maybe involved in the structural stability of DNA binding motifs. In this work we confirmed the Zn2+ upregulation expression of tvznf1 gene. Recombinant TvZNF1 was able to bind to specific DNA sequences according to EMSA assay. Additionally, we demonstrated that recombinant TvZNF1 bind to MRE signature in vitro, which strongly suggests its role in transcriptional regulation, similar to the one observed for mammalian MTF-1. This result suggested a conserved mechanism of genic regulation mediated by ZNFs in T. vaginalis.

  18. Does Δm = ΔErest/c2?

    Science.gov (United States)

    Redzic, Dragan V.

    2006-01-01

    We point out a logical possibility, based on special relativity, that the validity of Einstein's 1905 generalization, Δm = ΔErest/c2, might depend on how the energy of a body is defined in special relativity. The analysis is another illustration of the importance of Ockham's razor in special relativity.

  19. Chemical fractionations in meteorites. XI - C2 chondrites

    Science.gov (United States)

    Wolf, R.; Richter, G. R.; Woodrow, A. B.; Anders, E.

    1980-01-01

    Measurements of the compositions of 20 trace elements in the representative C2 chondrites Boriskino, Cold Bokkeveld, Erakot, Essebi, Haripura, Santa Cruz and Al Rais are reported. The contents of Ag, Au, Bi, Cd, Cs, Ge, In, Ir, Ni, Os, Pd, Rb, Re, Sb, Se, Sn, Te, Tl, U, and Zn were determined by radiochemical neutron activation analysis. The siderophile abundances of the C2 chondrites are found to be less uniform than those of other carbonaceous chondrites, while the C2R chondrite Al Rais is systematically lower in 12 volatiles than the C2M chondrites. Enrichment of Bi and Tl found in Erakot and Haripura indicate the possible presence of the late condensate mysterite. Volatile abundances are shown to agree with matrix contents for meteorites that have suffered little aqueous alteration, however to be 20-30% lower for the more altered meteorites. Finally, the decline of element abundance with volatility is shown to be consistent with the sigmoid curve explained by the two-component model.

  20. Heat tolerance of dairy lactococcal c2 phages

    DEFF Research Database (Denmark)

    Nielsen, Cecilie Lykke Marvig; Basheer, Aideh; Neve, H.

    2011-01-01

    Nine Lactococcus lactis c2 phages propagated on different hosts were screened for thermal resistance in skimmed milk. Pronounced variations in thermal resistance were found. Three phages displayed high sensitivity towards heat resulting in >8 log reductions after 70 °C for 5 min, whereas the most...

  1. Invariant Nonrecurrent Fatou Components of Automorphisms of $C^2$

    OpenAIRE

    Jupiter, Daniel; Lilov, Krastio

    2003-01-01

    We examine invariant nonrecurrent Fatou components of automorphisms of $\\mathbb{C}^2$ in the case where all limit maps are constant. We show that except in special cases there cannot be more than one such limit map. We also briefly examine such Fatou components where the limit maps may be nonconstant. Lastly we present a few examples of such Fatou components.

  2. Tunable C2N Membrane for High Efficient Water Desalination

    Science.gov (United States)

    Yang, Yanmei; Li, Weifeng; Zhou, Hongcai; Zhang, Xiaoming; Zhao, Mingwen

    2016-01-01

    Water scarcity represents one of the most serious global problems of our time and challenges the advancements in desalination techniques. Although water-filtering architectures based on graphene have greatly advanced the approach to high performance desalination membranes, the controlled-generation of nanopores with particular diameter is tricky and has stunted its wide applications. Here, through molecular dynamic simulations and first-principles calculations, we propose that the recently reported graphene-like carbon nitride (g-C2N) monolayer can serve as high efficient filters for water desalination. Taking the advantages of the intrisic nanoporous structure and excellent mechanical properties of g-C2N, high water transparency and strong salt filtering capability have been demonstrated in our simulations. More importantly, the “open” and “closed” states of the g-C2N filter can be precisely regulated by tensile strain. It is found that the water permeability of g-C2N is significantly higher than that reported for graphene filters by almost one order of magnitude. In the light of the abundant family of graphene-like carbon nitride monolayered materials, our results thus offer a promising approach to the design of high efficient filteration architectures. PMID:27384666

  3. 26 CFR 1.663(c)-2 - Rules of administration.

    Science.gov (United States)

    2010-04-01

    ....663(c)-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX..., that a separate economic interest exists. (b) Computation of distributable net income for each separate share—(1) General rule. The amount of distributable net income for any share under section 663(c) is...

  4. Active Shiga-like toxin produced by some Aeromonas spp., isolated in Mexico City

    Directory of Open Access Journals (Sweden)

    Ingrid Palma-Martínez

    2016-09-01

    Full Text Available Shiga-like toxins (Stx represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii and Aeromonas spp. Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS. The aim of this study was to identify the stx1/stx2 genes in clinical strains and in outer membrane vesicles (OMVs of Aeromonas spp., 66 strains were isolated from children who live in Mexico City and Shiga-like toxins effects were evaluated on Vero cell cultures.The capacity to express active, Stx1 and Stx2 toxins was determined on Vero cell cultures and the concentration of Shiga-like toxins was evaluated by lethal dose to 50% (LD50 assays, observing inhibition of damaged cells by specific monoclonal antibodies. The results obtained in this study support the hypothesis that the stx gene is another putative virulence factor of Aeromonas, and since this gene can be transferred horizontally through OMVs this genus should be included as a possible causal agents of gastroenteritis and it should be reported as part of standard health surveillance procedures.Furthermore, these results indicate that Aeromonas genus might be a potential causative agent of HUS.

  5. Characterization of cytolethal distending toxin of campylobacter species isolated from captive macaque monkeys.

    Science.gov (United States)

    Dassanayake, Rohana P; Zhou, You; Hinkley, Susanne; Stryker, Cynthia J; Plauche, Gail; Borda, Juan T; Sestak, Karol; Duhamel, Gerald E

    2005-02-01

    An association between certain Campylobacter species and enterocolitis in humans and nonhuman primates is well established, but the association between cytolethal distending toxin and disease is incompletely understood. The purpose of the present study was to examine Campylobacter species isolated from captive conventionally raised macaque monkeys for the presence of the cdtB gene and for cytolethal distending toxin activity. The identity of each isolate was confirmed on the basis of phenotypic and genotypic analyses. The presence of cytolethal distending toxin was confirmed on the basis of characteristic morphological changes in HeLa cells incubated with filter-sterilized whole-cell lysates of reference and monkey Campylobacter isolates and examinations by light microscopy, confocal microscopy, and flow cytometry. Although cdtB gene sequences were found in both Campylobacter jejuni and Campylobacter coli, the production of cytolethal distending toxin correlated positively (P < 0.0001) only with C. jejuni. We concluded that cytolethal distending toxin activity is a characteristic of C. jejuni. Our C. jejuni cdtB gene-specific PCR assay might be of assistance for differentiating toxigenic C. jejuni from C. coli in clinical laboratories.

  6. Two Distinct RNase Activities of CRISPR-C2c2 Enable Guide RNA Processing and RNA Detection

    OpenAIRE

    East-Seletsky, Alexandra; O’Connell, Mitchell R.; Knight, Spencer C.; Burstein, David; Cate, Jamie H. D.; Tjian, Robert; Doudna, Jennifer A.

    2016-01-01

    Bacterial adaptive immune systems employ CRISPRs (clustered regularly interspaced short palindromic repeats) and CRISPR-associated (Cas) proteins for RNA-guided nucleic acid cleavage1,2. Although generally targeted to DNA substrates3–5, the Type III and Type VI CRISPR systems direct interference complexes against single-stranded RNA (ssRNA) substrates6–9. In Type VI systems, the single-subunit C2c2 protein functions as an RNA-guided RNA endonuclease9,10. How this enzyme a...

  7. Transoral vertebroplasty for a C2 aneurysmal bone cyst.

    Science.gov (United States)

    Brage, Liberto; Roldán, Héctor; Plata-Bello, Julio; Martel, Diego; García-Marín, Víctor

    2016-07-01

    Aneurysmal bone cysts at the cervical spine represent a real challenge both diagnostically and therapeutically, especially in young patients. We present an unusual case of a C2 aneurysmal bone cyst expanding in the entire vertebral body in a girl successfully treated with a transoral vertebroplasty. This is a case report study. We report the case of a 17-year-old girl with a history of cervical pain and occipital headache after a car accident. Routine x-rays disclosed a C2 lesion. Her neurologic examination was normal. Computed tomography showed a lytic lesion occupying almost the entire body of the C2 vertebra. The cortical bone was intact but notably thinned. Magnetic resonance imaging revealed a cystic image with blood inside. Transoral vertebroplasty was selected among other surgical options for the following reasons: (1) to improve the clinical symptoms, and (2) to prevent future vertebral collapse with devastating neurologic consequences. Under general anesthesia and continuous neurophysiological monitoring, we conducted a fluoroscopic-guided transoral vertebroplasty through a Jamshidi needle. A cytology sample from the cystic lesion was taken through the needle. The blood smear showed no tumoral cellularity. There were no complications during surgery or postoperative infections. After 4 years of follow-up, the patient is pain-free and leads a normal life. Transoral vertebroplasty seems to be a direct, safe, and effective technique to stabilize cystic lesions that endanger the stability of C2 and to improve symptoms. Aneurysmal bone cysts should be included in the differential diagnosis of lytic lesions at the C2 vertebral body. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Gene

    Data.gov (United States)

    U.S. Department of Health & Human Services — Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes,...

  9. Role of UPR Pathway in Defense Response of Aedes aegypti against Cry11Aa Toxin from Bacillus thuringiensis

    Directory of Open Access Journals (Sweden)

    Alejandra Bravo

    2013-04-01

    Full Text Available The insecticidal Cry toxins are pore-forming toxins produced by the bacteria Bacillus thuringiensis that disrupt insect-midgut cells. Cells can trigger different survival mechanisms to counteract the effects of sub-lytic doses of pore forming toxins. Particularly, two signaling pathways have been demonstrated to play a role in the defense mechanism to other toxins in Caenorhabditis elegans and in mammalian cells. These are the unfolded protein response (UPR and the sterol regulatory element binding proteins (SREBP pathways, which are proposed to facilitate membrane repair responses. In this work we analyzed the role of these pathways in Aedes aegypti response to intoxication with Cry11Aa toxin. We show that UPR is activated upon toxin ingestion. The role of these two pathways was analyzed in vivo by using RNA interference. We silenced the expression of specific proteins in A. aegypti larvae. Gene silencing of Ire-1 and Xbp-1 proteins from UPR system, resulted in hypersensitive to Cry11Aa toxin action. In contrast, silencing of Cas-1, Scap and S2P from SREBP pathway had no affect on Cry11Aa toxicity in A. aegypti larvae. However, the role of SREBP pathway requires further studies to be conclusive. Our data indicate that the UPR pathway is involved in the insect defense against Cry toxins.

  10. Are Fireworms Venomous? Evidence for the Convergent Evolution of Toxin Homologs in Three Species of Fireworms (Annelida, Amphinomidae)

    Science.gov (United States)

    Simpson, Danny

    2018-01-01

    Abstract Amphinomids, more commonly known as fireworms, are a basal lineage of marine annelids characterized by the presence of defensive dorsal calcareous chaetae, which break off upon contact. It has long been hypothesized that amphinomids are venomous and use the chaetae to inject a toxic substance. However, studies investigating fireworm venom from a morphological or molecular perspective are scarce and no venom gland has been identified to date, nor any toxin characterized at the molecular level. To investigate this question, we analyzed the transcriptomes of three species of fireworms—Eurythoe complanata, Hermodice carunculata, and Paramphinome jeffreysii—following a venomics approach to identify putative venom compounds. Our venomics pipeline involved de novo transcriptome assembly, open reading frame, and signal sequence prediction, followed by three different homology search strategies: BLAST, HMMER sequence, and HMMER domain. Following this pipeline, we identified 34 clusters of orthologous genes, representing 13 known toxin classes that have been repeatedly recruited into animal venoms. Specifically, the three species share a similar toxin profile with C-type lectins, peptidases, metalloproteinases, spider toxins, and CAP proteins found among the most highly expressed toxin homologs. Despite their great diversity, the putative toxins identified are predominantly involved in three major biological processes: hemostasis, inflammatory response, and allergic reactions, all of which are commonly disrupted after fireworm stings. Although the putative fireworm toxins identified here need to be further validated, our results strongly suggest that fireworms are venomous animals that use a complex mixture of toxins for defense against predators. PMID:29293976

  11. Diversity of Clostridium perfringens toxin-genotypes from dairy farms.

    Science.gov (United States)

    Fohler, Svenja; Klein, Guenter; Hoedemaker, Martina; Scheu, Theresa; Seyboldt, Christian; Campe, Amely; Jensen, Katharina Charlotte; Abdulmawjood, Amir

    2016-08-30

    Clostridium (C.) perfringens is the causative agent of several diseases in animals and humans, including histotoxic and enteric infections. To gain more insight into the occurrence of its different toxin-genotypes in dairy herds, including those toxin genes previously associated with diseases in cattle or humans, 662 isolates cultivated from feces, rumen content and feed collected from 139 dairy farms were characterized by PCR (detecting cpa, cpb, iap, etx, cpe, and both allelic variants of cpb2). Isolates from feces were assigned to type A (cpa positive, n = 442) and D (cpa and etx positive, n = 2). Those from rumen content (n = 207) and feed (n = 13) were all assigned to type A. The consensus and atypical variants of the cpb2 gene were detected in 64 (14.5 %) and 138 (31.22 %) of all isolates from feces, and 30 (14.5 %) and 54 (26.1 %) of all isolates from rumen content, respectively. Both allelic variants of cpb2 occurred frequently in animals without signs of acute enteric disease, whereby the atypical variant dominated. Five (0.8 %) of all type A isolates were positive for the cpe gene. Therefore, the present study indicates that dairy cows are no primary source for potentially human pathogenic enterotoxin gene positive strains.

  12. Folic acid is necessary for proliferation and differentiation of C2C12 myoblasts.

    Science.gov (United States)

    Hwang, Seong Y; Kang, Yong J; Sung, Bokyung; Jang, Jung Y; Hwang, Na L; Oh, Hye J; Ahn, Yu R; Kim, Hong J; Shin, Jin H; Yoo, Mi-Ae; Kim, Cheol M; Chung, Hae Y; Kim, Nam D

    2017-05-04

    Folic acid, a water soluble B vitamin, plays an important role in cellular metabolic activities, such as functioning as a cofactor in one-carbon metabolism for DNA and RNA synthesis as well as nucleotide and amino acid biosynthesis in the body. A lack of dietary folic acid can lead to folic acid deficiency and result in several health problems, including macrocytic anemia, elevated plasma homocysteine, cardiovascular disease, birth defects, carcinogenesis, muscle weakness, and walking difficulty. However, the effect of folic acid deficiency on skeletal muscle development and its molecular mechanisms are unknown. We, therefore, investigated the effect of folic acid deficiency on myogenesis in skeletal muscle cells and found that folic acid deficiency induced proliferation inhibition and cell cycle breaking as well as cellular senescence in C2C12 myoblasts, implying that folic acid deficiency influences skeletal muscle development. Folic acid deficiency also inhibited differentiation of C2C12 myoblasts and induced deregulation of the cell cycle exit and many cell cycle regulatory genes. It inhibited expression of muscle-specific marker MyHC as well as myogenic regulatory factor (myogenin). Moreover, immunocytochemistry and Western blot analyses revealed that DNA damage was more increased in folic acid-deficient medium-treated differentiating C2C12 cells. Furthermore, we found that folic acid resupplementation reverses the effect on the cell cycle and senescence in folic acid-deficient C2C12 myoblasts but does not reverse the differentiation of C2C12 cells. Altogether, the study results suggest that folic acid is necessary for normal development of skeletal muscle cells. © 2017 Wiley Periodicals, Inc.

  13. The Metabolic Effects of Traditional Chinese Medication Qiliqiangxin on H9C2 Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Shenghui Lin

    2015-11-01

    Full Text Available Background/Aims: A traditional Chinese medicine, Qiliqiangxin (QLQX has been identified to perform protective effects on myocardium energy metabolism in mice with acute myocardial infarction, though the effects of QLQX on myocardial mitochondrial biogenesis under physiological condition is still largely elusive. Methods: H9C2 cells were treated with different concentrations of QLQX (0.25, 0.5, and 1.0 µg/mL from 6 to 48 hours. Oxidative metabolism and glycolysis were measured by oxygen consumption and extracellular acidification with XF96 analyzer (SeaHorse. Mitochondrial content and ultrastructure were assessed by Mitotracker staining, confocal microscopy, flow cytometry, and transmission electron microscopy. Mitochondrial biogenesis-related genes were measured by qRT-PCR and Western blot. Results: H9C2 cells treated with QLQX exhibited increased glycolysis at earlier time points (6, 12, and 24 hours, while QLQX could enhance oxidative metabolism and mitochondrial uncoupling in H9C2 cells with longer duration of treatment (48 hours. QLQX also increased mitochondrial content and mitochondrial biogenesis-related gene expression levels, including 16sRNA, SSBP1, TWINKLE, TOP1MT and PLOG, with an activation of peroxisome proliferator-activated receptor coactivator 1 alpha (PGC-1α and its downstream effectors. Silencing PGC-1α could abolish the increased mitochondrial content in H9C2 cells treated with QLQX. Conclusion: Our study is the first to document enhanced metabolism in cardiomyocytes treated with QLQX, which is linked to increased mitochondrial content and mitochondrial biogenesis via activation of PGC-1α.

  14. Beta2 toxin is not involved in in vitro cell cytotoxicity caused by human and porcine cpb2-harbouring Clostridium perfringens.

    Science.gov (United States)

    Allaart, Janneke G; van Asten, Alphons J A M; Vernooij, Johannes C M; Gröne, Andrea

    2014-06-25

    Clostridium perfringens is a common cause of intestinal disease in animals and humans. Its pathogenicity is attributed to the toxins it can produce, including the beta2 toxin. The presence of cpb2, the gene encoding the beta2 toxin, has been associated with diarrhoea in neonatal piglets and humans. However, the exact role of the beta2 toxin in the development of diarrhoea is still unknown. In this study we investigated the level of cytotoxicity to porcine IPI-21 and human Caco-2 cell-lines caused by porcine and human cpb2-harbouring C. perfringens and the significance of the beta2 toxin for the induction of cell cytotoxicity. Supernatants of porcine cpb2-harbouring C. perfringens strains were cytotoxic to both cell lines. Cell cytotoxicity caused by supernatant of human cpb2-harbouring C. perfringens strains was variable among strains. However, removal of the beta2 toxin by anti-beta2 toxin antibodies or degradation of the beta2 toxin by trypsin did not reduce the cytotoxic effect of any of the supernatants. These data suggest that beta2 toxin does not play a role in the development of cell cytotoxicity in in vitro experiments. In vivo studies are necessary to definitely define the role of beta2 toxin in the development of cell cytotoxicity and subsequent diarrhoea. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Synthesis and biology of cyclic imine toxins, an emerging class of potent, globally distributed marine toxins.

    Science.gov (United States)

    Stivala, Craig E; Benoit, Evelyne; Aráoz, Rómulo; Servent, Denis; Novikov, Alexei; Molgó, Jordi; Zakarian, Armen

    2015-03-01

    From a small group of exotic compounds isolated only two decades ago, Cyclic Imine (CI) toxins have become a major class of marine toxins with global distribution. Their distinct chemical structure, biological mechanism of action, and intricate chemistry ensures that CI toxins will continue to be the subject of fascinating fundamental studies in the broad fields of chemistry, chemical biology, and toxicology. The worldwide occurrence of potent CI toxins in marine environments, their accumulation in shellfish, and chemical stability are important considerations in assessing risk factors for human health. This review article aims to provide an account of chemistry, biology, and toxicology of CI toxins from their discovery to the present day.

  16. Combinations of long peptide sequence blocks can be used to describe toxin diversification in venomous animals.

    Science.gov (United States)

    Starcevic, Antonio; Moura-da-Silva, Ana M; Cullum, John; Hranueli, Daslav; Long, Paul F

    2015-03-01

    An important mechanism for the evolution of toxins in venomous animals is believed to be the acquisition of genes encoding proteins that switch from physiological to toxic roles following gene duplication. The 'reverse recruitment' hypothesis pertains that these genes can also revert back to physiological functions, although such events are thought to be rare. A non-supervised homology searching method was developed which allowed the peptide diversity of animal toxins to be described as combinations between limited numbers of amino-acid sequence blocks we called 'tox-bits'. Taking the phospholipase A2 (PLA2) protein family as an example, a Bernoulli Trial was used to test if 'tox-bits' were robust enough to distinguish between peptides with physiological or toxin functions. The analysis revealed that discrimination was indeed possible, and supports the very recent 'restriction' hypothesis whereby genes with the potential to encode toxic functions have likely been independently recruited into venom systems and therefore require few, if any, reverse recruitment events. The development of 'tox-bits' provides a novel bioinformatics tool to allow recognition of toxins from other proteins in genome sequences, facilitating the study of gene recruitment and duplication strategies in venom diversification. The 'tox-bits' library is freely available at http://bioserv.pbf.hr/blocks.zip. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Vth Pan American Symposium on Animal, Plant and Microbial Toxins

    National Research Council Canada - National Science Library

    Ownby, Charlotte

    1996-01-01

    ..., cardiotoxins, and antihemorrhagic factors. Presentations on plant and microbial toxins include work done on ricin, Clostridium perfringens enterotoxin, cone snail peptides, sea anemone toxins, proteinase inhibitors and maitotoxin...

  18. SNAKE VENOMICS OF Crotalus tigris: THE MINIMALIST TOXIN ARSENAL OF THE DEADLIEST NEARTIC RATTLESNAKE VENOM

    Science.gov (United States)

    CALVETE, Juan J.; PÉREZ, Alicia; LOMONTE, Bruno; SÁNCHEZ, Elda E.; SANZ, Libia

    2012-01-01

    We report the proteomic and antivenomic characterization of Crotalus tigris venom. This venom exhibits the highest lethality for mice among rattlesnakes and the simplest toxin proteome reported to date. The venom proteome of C. tigris comprises 7–8 gene products from 6 toxin families: the presynaptic β-neurotoxic heterodimeric PLA2, Mojave toxin, and two serine proteinases comprise, respectively, 66% and 27% of the C. tigris toxin arsenal, whereas a VEGF-like protein, a CRISP molecule, a medium-sized disintegrin, and 1–2 PIII-SVMPs, each represents 0.1–5% of the total venom proteome. This toxin profile really explains the systemic neuro- and myotoxic effects observed in envenomated animals. In addition, we found that venom lethality of C. tigris and other North American rattlesnake type II venoms correlates with the concentration of Mojave toxin A-subunit, supporting the view that the neurotoxic venom phenotype of crotalid type II venoms may be described as a single-allele adaptation. Our data suggest that the evolutionary trend towards neurotoxicity, which has been also reported for the South American rattlesnakes, may have resulted by paedomorphism. The ability of an experimental antivenom to effectively immunodeplete proteins from the type II venoms of C. tigris, C. horridus, C. oreganus helleri, C. scutulatus scutulatus, and S. catenatus catenatus, indicated the feasibility of generating a pan-American anti-Crotalus type II antivenom, suggested by the identification of shared evolutionary trends among South American and North American Crotalus. PMID:22181673

  19. sRNA Antitoxins: More than One Way to Repress a Toxin

    Directory of Open Access Journals (Sweden)

    Jia Wen

    2014-08-01

    Full Text Available Bacterial toxin-antitoxin loci consist of two genes: one encodes a potentially toxic protein, and the second, an antitoxin to repress its function or expression. The antitoxin can either be an RNA or a protein. For type I and type III loci, the antitoxins are RNAs; however, they have very different modes of action. Type I antitoxins repress toxin protein expression through interacting with the toxin mRNA, thereby targeting the mRNA for degradation or preventing its translation or both; type III antitoxins directly bind to the toxin protein, sequestering it. Along with these two very different modes of action for the antitoxin, there are differences in the functions of the toxin proteins and the mobility of these loci between species. Within this review, we discuss the major differences as to how the RNAs repress toxin activity, the potential consequences for utilizing different regulatory strategies, as well as the confirmed and potential biological roles for these loci across bacterial species.

  20. East1 toxin and its presence in a changing microbial world

    Directory of Open Access Journals (Sweden)

    C. P. Sousa

    2003-01-01

    Full Text Available This review shows the structure, mode of action, and actual epidemiological data about EAST1 toxin. It is a particularly intriguing bacterial toxin that may subvert multiple cellular processes to yield intestinal epithelial cell secretion. EAST1 toxin was first described in strains of EAggEC that were associated with persistent diarrhea primarily in developing world countries. Molecular organization, mobility, and data in literature are suggesting that EAST1 could be a transposon. The insertion sequences in Escherichia coli and some of the usual transposition mechanisms as well as regulation are reviewed. This review emphasizes the presence of the gene astA in EPEC, EAggEC, A-EPEC, ETEC, DAEC, EIEC, and in non-diarrheagenic E. coli. It also discusses here the presence of the astA gene in Salmonella spp. and future perspectives for understanding its role in diarrheal disease in both bacterial genera.

  1. Clostridium difficile PCR Cycle Threshold Predicts Free Toxin.

    Science.gov (United States)

    Senchyna, Fiona; Gaur, Rajiv L; Gombar, Saurabh; Truong, Cynthia Y; Schroeder, Lee F; Banaei, Niaz

    2017-09-01

    There is no stand-alone Clostridium difficile diagnostic that can sensitively and rapidly detect fecal free toxins. We investigated the performance of the C. difficile PCR cycle threshold ( C T ) for predicting free toxin status. Consecutive stool samples ( n = 312) positive for toxigenic C. difficile by the GeneXpert C. difficile /Epi tcdB PCR assay were tested with the rapid membrane C. Diff Quik Chek Complete immunoassay (RMEIA). RMEIA toxin-negative samples were tested with the cell cytotoxicity neutralization assay (CCNA) and tgcBIOMICS enzyme-linked immunosorbent assay (ELISA). Using RMEIA alone or in combination with CCNA and/or ELISA as the reference method, the accuracy of C T was measured at different C T cutoffs. Using RMEIA as the reference method, a C T cutoff of 26.35 detected toxin-positive samples with a sensitivity, specificity, positive predictive value, and negative predictive value of 96.0% (95% confidence interval [CI], 90.2% to 98.9%), 65.9% (95% CI, 59.0% to 72.2%), 57.4% (95% CI, 52.7% to 62%), and 97.1% (95% CI, 92.8% to 98.9), respectively. Inclusion of CCNA in the reference method improved C T specificity to 78.0% (95% CI, 70.7% to 84.2%). Intercartridge lot C T variability measured as the average coefficient of variation was 2.8% (95% CI, 1.2% to 3.2%). Standardizing the input stool volume did not improve C T toxin specificity. The median C T values were not significantly different between stool samples with Bristol scores of 5, 6, and 7, between pediatric and adult samples, or between presumptive 027 and non-027 strains. In addition to sensitively detecting toxigenic C. difficile in stool, on-demand PCR may also be used to accurately predict toxin-negative stool samples, thus providing additional results in PCR-positive stool samples to guide therapy. Copyright © 2017 American Society for Microbiology.

  2. Recent insights into Pasteurella multocida toxin and other G-protein-modulating bacterial toxins.

    Science.gov (United States)

    Wilson, Brenda A; Ho, Mengfei

    2010-08-01

    Over the past few decades, our understanding of the bacterial protein toxins that modulate G proteins has advanced tremendously through extensive biochemical and structural analyses. This article provides an updated survey of the various toxins that target G proteins, ending with a focus on recent mechanistic insights in our understanding of the deamidating toxin family. The dermonecrotic toxin from Pasteurella multocida (PMT) was recently added to the list of toxins that disrupt G-protein signal transduction through selective deamidation of their targets. The C3 deamidase domain of PMT has no sequence similarity to the deamidase domains of the dermonecrotic toxins from Escherichia coli (cytotoxic necrotizing factor [CNF]1-3), Yersinia (CNFY) and Bordetella (dermonecrotic toxin). The structure of PMT-C3 belongs to a family of transglutaminase-like proteins, with active site Cys-His-Asp catalytic triads distinct from E. coli CNF1.

  3. Stealth and mimicry by deadly bacterial toxins

    DEFF Research Database (Denmark)

    Yates, S.P.; Jørgensen, Rene; Andersen, Gregers Rom

    2006-01-01

    Diphtheria toxin and exotoxin A are well-characterized members of the ADP-ribosyltransferase toxin family that serve as virulence factors in the pathogenic bacteria, Corynebacterium diphtheriae and Pseudomonas aeruginosa.  New high-resolution structural data of the Michaelis complex of the Pseudo...

  4. Botulinum toxin — therapeutic effect in cosmetology

    Directory of Open Access Journals (Sweden)

    Morrison A.V.

    2016-09-01

    Full Text Available This review presents the data from published literatures and the research works conducted by the authors about mechanisms of action of botulinum toxin and its use in the practical medicine (particularly in dermatology and cosmetology. Indications and contraindications of botulinum toxin use in cosmetology are also considered in this work.

  5. Botulinum toxin — therapeutic effect in cosmetology

    OpenAIRE

    Morrison A.V.; Bocharova Y.M.; Morrison V.V.

    2016-01-01

    This review presents the data from published literatures and the research works conducted by the authors about mechanisms of action of botulinum toxin and its use in the practical medicine (particularly in dermatology and cosmetology). Indications and contraindications of botulinum toxin use in cosmetology are also considered in this work.

  6. Toxin-Antitoxin Battle in Bacteria

    DEFF Research Database (Denmark)

    Cataudella, Ilaria

    This PhD thesis consists of three research projects revolving around the common thread of investigation of the properties and biological functions of Toxin-Antitoxin loci. Toxin-Antitoxin (TA) loci are transcriptionally regulated via an auto-inhibition mechanism called conditional cooperativity, ...

  7. T-2 toxin adsorption by hectorite

    Directory of Open Access Journals (Sweden)

    ALEKSANDRA DAKOVIĆ

    2009-11-01

    Full Text Available The adsorption of T-2 toxin by the natural smectite mineral – hectorite at pH 3.0, 7.0 and 9.0 was investigated. The results of T-2 toxin adsorption on hectorite showed that the T-2 adsorption capacity decreased with increasing concentration of adsorbent in the suspension for all the investigated pH values. From the adsorption isotherms, an increase in T-2 toxin adsorption with increasing initial T-2 toxin concentration was observed for all the investigated pH values. The T-2 toxin adsorption by hectorite followed a non-linear (Langmuir type of isotherm at pH 3.0, 7.0 and 9.0, with correlation coefficients (r2 of 0.943 at pH 3.0, 0.919 at pH 7.0 and 0.939 at pH 9.0. The estimated maximum T-2 toxin adsorption by hectorite based on the Langmuir fit to the data (9.178 mg/g at pH 3.0, 9.930 mg/g at pH 7.0, and 19.341 mg/g at pH 9.0, indicated that the adsorption of T-2 toxin by hectorite is pH dependent. The obtained data suggest the existence of specific active sites in hectorite onto which the T-2 toxin is adsorbed.

  8. Tetra- versus Pentavalent Inhibitors of Cholera Toxin

    NARCIS (Netherlands)

    Fu, Ou; Pukin, Aliaksei V.; Quarles Van Ufford, Linda; Branson, Thomas R.; Thies-Weesie, Dominique M E; Turnbull, W. Bruce; Visser, Gerben M.; Pieters, Roland J.

    2015-01-01

    The five B-subunits (CTB5) of the Vibrio cholerae (cholera) toxin can bind to the intestinal cell surface so the entire AB5 toxin can enter the cell. Simultaneous binding can occur on more than one of the monosialotetrahexosylganglioside (GM1) units present on the cell surface.

  9. Plant Insecticidal Toxins in Ecological Networks

    Directory of Open Access Journals (Sweden)

    Sébastien Ibanez

    2012-04-01

    Full Text Available Plant secondary metabolites play a key role in plant-insect interactions, whether constitutive or induced, C- or N-based. Anti-herbivore defences against insects can act as repellents, deterrents, growth inhibitors or cause direct mortality. In turn, insects have evolved a variety of strategies to act against plant toxins, e.g., avoidance, excretion, sequestration and degradation of the toxin, eventually leading to a co-evolutionary arms race between insects and plants and to co-diversification. Anti-herbivore defences also negatively impact mutualistic partners, possibly leading to an ecological cost of toxin production. However, in other cases toxins can also be used by plants involved in mutualistic interactions to exclude inadequate partners and to modify the cost/benefit ratio of mutualism to their advantage. When considering the whole community, toxins have an effect at many trophic levels. Aposematic insects sequester toxins to defend themselves against predators. Depending on the ecological context, toxins can either increase insects’ vulnerability to parasitoids and entomopathogens or protect them, eventually leading to self-medication. We conclude that studying the community-level impacts of plant toxins can provide new insights into the synthesis between community and evolutionary ecology.

  10. Plant insecticidal toxins in ecological networks.

    Science.gov (United States)

    Ibanez, Sébastien; Gallet, Christiane; Després, Laurence

    2012-04-01

    Plant secondary metabolites play a key role in plant-insect interactions, whether constitutive or induced, C- or N-based. Anti-herbivore defences against insects can act as repellents, deterrents, growth inhibitors or cause direct mortality. In turn, insects have evolved a variety of strategies to act against plant toxins, e.g., avoidance, excretion, sequestration and degradation of the toxin, eventually leading to a co-evolutionary arms race between insects and plants and to co-diversification. Anti-herbivore defences also negatively impact mutualistic partners, possibly leading to an ecological cost of toxin production. However, in other cases toxins can also be used by plants involved in mutualistic interactions to exclude inadequate partners and to modify the cost/benefit ratio of mutualism to their advantage. When considering the whole community, toxins have an effect at many trophic levels. Aposematic insects sequester toxins to defend themselves against predators. Depending on the ecological context, toxins can either increase insects' vulnerability to parasitoids and entomopathogens or protect them, eventually leading to self-medication. We conclude that studying the community-level impacts of plant toxins can provide new insights into the synthesis between community and evolutionary ecology.

  11. MARTX toxins as effector delivery platforms.

    Science.gov (United States)

    Gavin, Hannah E; Satchell, Karla J F

    2015-12-01

    Bacteria frequently manipulate their host environment via delivery of microbial 'effector' proteins to the cytosol of eukaryotic cells. In the case of the multifunctional autoprocessing repeats-in-toxins (MARTX) toxin, this phenomenon is accomplished by a single, >3500 amino acid polypeptide that carries information for secretion, translocation, autoprocessing and effector activity. MARTX toxins are secreted from bacteria by dedicated Type I secretion systems. The released MARTX toxins form pores in target eukaryotic cell membranes for the delivery of up to five cytopathic effectors, each of which disrupts a key cellular process. Targeted cellular processes include modulation or modification of small GTPases, manipulation of host cell signaling and disruption of cytoskeletal integrity. More recently, MARTX toxins have been shown to be capable of heterologous protein translocation. Found across multiple bacterial species and genera--frequently in pathogens lacking Type 3 or Type 4 secretion systems--MARTX toxins in multiple cases function as virulence factors. Innovative research at the intersection of toxin biology and bacterial genetics continues to elucidate the intricacies of the toxin as well as the cytotoxic mechanisms of its diverse effector collection. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Inactivation of class II PI3K-C2α induces leptin resistance, age-dependent insulin resistance and obesity in male mice.

    Science.gov (United States)

    Alliouachene, Samira; Bilanges, Benoit; Chaussade, Claire; Pearce, Wayne; Foukas, Lazaros C; Scudamore, Cheryl L; Moniz, Larissa S; Vanhaesebroeck, Bart

    2016-07-01

    While the class I phosphoinositide 3-kinases (PI3Ks) are well-documented positive regulators of metabolism, the involvement of class II PI3K isoforms (PI3K-C2α, -C2β and -C2γ) in metabolic regulation is just emerging. Organismal inactivation of PI3K-C2β increases insulin signalling and sensitivity, whereas PI3K-C2γ inactivation has a negative metabolic impact. In contrast, the role of PI3K-C2α in organismal metabolism remains unexplored. In this study, we investigated whether kinase inactivation of PI3K-C2α affects glucose metabolism in mice. We have generated and characterised a mouse line with a constitutive inactivating knock-in (KI) mutation in the kinase domain of the gene encoding PI3K-C2α (Pik3c2a). While homozygosity for kinase-dead PI3K-C2α was embryonic lethal, heterozygous PI3K-C2α KI mice were viable and fertile, with no significant histopathological findings. However, male heterozygous mice showed early onset leptin resistance, with a defect in leptin signalling in the hypothalamus, correlating with a mild, age-dependent obesity, insulin resistance and glucose intolerance. Insulin signalling was unaffected in insulin target tissues of PI3K-C2α KI mice, in contrast to previous reports in which downregulation of PI3K-C2α in cell lines was shown to dampen insulin signalling. Interestingly, no metabolic phenotypes were detected in female PI3K-C2α KI mice at any age. Our data uncover a sex-dependent role for PI3K-C2α in the modulation of hypothalamic leptin action and systemic glucose homeostasis. All reagents are available upon request.

  13. Botulinum toxin in poststroke spasticity.

    Science.gov (United States)

    Ozcakir, Suheda; Sivrioglu, Koncuy

    2007-06-01

    Poststroke hemiparesis, together with abnormal muscle tone, is a major cause of morbidity and disability. Although most hemiparetic patients are able to reach different ambulatory levels with rehabilitation efforts, upper and lower limb spasticity can impede activities of daily living, personal hygiene, ambulation and, in some cases, functional improvement. The goals of spasticity management include increasing mobility and range of motion, attaining better hygiene, improving splint wear and other functional activities. Conservative measures, such as positioning, stretching and exercise are essential in spasticity management, but alone often are inadequate to effectively control it. Oral antispastic medications often provide limited effects with short duration and frequent unwanted systemic side effects, such as weakness, sedation and dry mouth. Therefore, neuromuscular blockade by local injections have become the first choice for the treatment of focal spasticity, particularly in stroke patients. Botulinum toxin (BTX), being one of the most potent biological toxins, acts by blocking neuromuscular transmission via inhibiting acetylcholine release. Currently, focal spasticity is being treated successfully with BTX via injecting in the spastic muscles. Two antigenically distinct serotypes of BTX are available on the market as type A and B. Clinical studies of BTX used for spastic hemiplegic patients are reviewed in this article in two major categories, upper and lower limb applications. This review addresses efficacy in terms of outcome measures, such as muscle tone reduction and functional outcome, as well as safety issues. Application modifications of dose, dilutions, site of injections and combination therapies with BTX injections are also discussed.

  14. Discovery and Classification of DES15C2kyh

    Science.gov (United States)

    Graham, M. L.; Filippenko, A. V.; Nugent, P.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; D'Andrea, C.; Smith, M.; Sullivan, M.; Childress, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Perlmutter, S.; Foley, R. J.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.

    2015-10-01

    We report optical spectroscopy of DES15C2kyh discovered by the Dark Energy Survey. The spectrum (340-1025nm) was obtained using LRIS on Keck-I. Object classification was performed using superfit (Howell et al, 2005, ApJ, 634, 1190) and SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), the details of which are reported in the table below.

  15. Immunotoxins: The Role of the Toxin

    Directory of Open Access Journals (Sweden)

    David FitzGerald

    2013-08-01

    Full Text Available Immunotoxins are antibody-toxin bifunctional molecules that rely on intracellular toxin action to kill target cells. Target specificity is determined via the binding attributes of the chosen antibody. Mostly, but not exclusively, immunotoxins are purpose-built to kill cancer cells as part of novel treatment approaches. Other applications for immunotoxins include immune regulation and the treatment of viral or parasitic diseases. Here we discuss the utility of protein toxins, of both bacterial and plant origin, joined to antibodies for targeting cancer cells. Finally, while clinical goals are focused on the development of novel cancer treatments, much has been learned about toxin action and intracellular pathways. Thus toxins are considered both medicines for treating human disease and probes of cellular function.

  16. Novel receptors for bacterial protein toxins.

    Science.gov (United States)

    Schmidt, Gudula; Papatheodorou, Panagiotis; Aktories, Klaus

    2015-02-01

    While bacterial effectors are often directly introduced into eukaryotic target cells by various types of injection machines, toxins enter the cytosol of host cells from endosomal compartments or after retrograde transport via Golgi from the ER. A first crucial step of toxin-host interaction is receptor binding. Using optimized protocols and new methods novel toxin receptors have been identified, including metalloprotease ADAM 10 for Staphylococcus aureus α-toxin, laminin receptor Lu/BCAM for Escherichia coli cytotoxic necrotizing factor CNF1, lipolysis stimulated lipoprotein receptor (LSR) for Clostridium difficile transferase CDT and low-density lipoprotein receptor-related protein (LRP) 1 for Clostridium perfringens TpeL toxin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Toxins and Secretion Systems of Photorhabdus luminescens

    Directory of Open Access Journals (Sweden)

    Athina Rodou

    2010-06-01

    Full Text Available Photorhabdus luminescens is a nematode-symbiotic, gram negative, bioluminescent bacterium, belonging to the family of Enterobacteriaceae.Recent studies show the importance of this bacterium as an alternative source of insecticides, as well as an emerging human pathogen. Various toxins have been identified and characterized in this bacterium. These toxins are classified into four major groups: the toxin complexes (Tcs, the Photorhabdus insect related (Pir proteins, the “makes caterpillars floppy” (Mcf toxins and the Photorhabdus virulence cassettes (PVC; the mechanisms however of toxin secretion are not fully elucidated. Using bioinformatics analysis and comparison against the components of known secretion systems, multiple copies of components of all known secretion systems, except the ones composing a type IV secretion system, were identified throughout the entire genome of the bacterium. This indicates that Photorhabdus luminescens has all the necessary means for the secretion of virulence factors, thus it is capable of establishing a microbial infection.

  18. Interplay between toxin transport and flotillin localization

    DEFF Research Database (Denmark)

    Pust, Sascha; Dyve, Anne Berit; Torgersen, Maria L

    2010-01-01

    The flotillin proteins are localized in lipid domains at the plasma membrane as well as in intracellular compartments. In the present study, we examined the importance of flotillin-1 and flotillin-2 for the uptake and transport of the bacterial Shiga toxin (Stx) and the plant toxin ricin and we...... investigated whether toxin binding and uptake were associated with flotillin relocalization. We observed a toxin-induced redistribution of the flotillins, which seemed to be regulated in a p38-dependent manner. Our experiments provide no evidence for a changed endocytic uptake of Stx or ricin in cells silenced...... for flotillin-1 or -2. However, the Golgi-dependent sulfation of both toxins was significantly reduced in flotillin knockdown cells. Interestingly, when the transport of ricin to the ER was investigated, we obtained an increased mannosylation of ricin in flotillin-1 and flotillin-2 knockdown cells. The toxicity...

  19. Toxins and secretion systems of Photorhabdus luminescens.

    Science.gov (United States)

    Rodou, Athina; Ankrah, Dennis O; Stathopoulos, Christos

    2010-06-01

    Photorhabdus luminescens is a nematode-symbiotic, gram negative, bioluminescent bacterium, belonging to the family of Enterobacteriaceae. Recent studies show the importance of this bacterium as an alternative source of insecticides, as well as an emerging human pathogen. Various toxins have been identified and characterized in this bacterium. These toxins are classified into four major groups: the toxin complexes (Tcs), the Photorhabdus insect related (Pir) proteins, the "makes caterpillars floppy" (Mcf) toxins and the Photorhabdus virulence cassettes (PVC); the mechanisms however of toxin secretion are not fully elucidated. Using bioinformatics analysis and comparison against the components of known secretion systems, multiple copies of components of all known secretion systems, except the ones composing a type IV secretion system, were identified throughout the entire genome of the bacterium. This indicates that Photorhabdus luminescens has all the necessary means for the secretion of virulence factors, thus it is capable of establishing a microbial infection.

  20. Functional mapping of factor VIII C2 domain.

    Science.gov (United States)

    Pellequer, Jean-Luc; Chen, Shu-wen W; Saboulard, Didier; Delcourt, Marc; Négrier, Claude; Plantier, Jean-Luc

    2011-07-01

    The factor VIII (FVIII) is a cofactor of the coagulation cascade. The FVIII C2 domain is a critical domain that participates in the interactions with the von Willebrand factor and the phospholipidic surfaces. To assess the importance of each residue of this domain in the maintenance of the structure and the function of FVIII, a number (n=139) of mutants were generated by substituting the original residues, from Ser2173 to Gly2325, by an alanine. Mutants were built within a complete B domain-deleted FVIII and expressed in COS-1 cells. Mutant antigen levels and procoagulant activities were measured. Two in silico analyses, a sliding average procedure and an analysis of the mutation energy cost were conducted in parallel on the FVIII structure. Both results were in agreement with the functional data, and illustrated the benefit of using such strategies prior to targeting specific residues in the aim of generating active recombinant molecules. The functional assays identify the residues that are important to maintaining the structure of the C2 domain, mainly those forming β-sheet, and those that can afford substitution, establishing a detailed functional relation with the available crystallographic data. This study provided a comprehensive functional mapping of the FVIII C2 domain and discussed the implication of specific residues in respect to the maintenance in the activity and structure stability, the efficiency in secretion, the binding to phospholipids and the formation of epitope.

  1. Electronically Excited C2 from Laser Photodissociated C60

    Science.gov (United States)

    Arepalli, Sivaram; Scott, Carl D.; Nikolaev, Pavel; Smalley, Richard E.

    1999-01-01

    Spectral and transient emission measurements are made of radiation from products of laser excitation of buckminsterfullerene (C60) vapor diluted in argon at 973 K. The principal radiation is from the Swan band system of C2 and, at early times, also from a black body continuum. The C2 radiation is observed only when C60 is excited by green (532 nm) and not with IR (1064 nm) laser radiation at energy densities of about 1.5 J/square cm. Transient measurements indicate that there are two characteristic periods of decay of radiation. The first period, lasting about 2 micro seconds, has a characteristic decay time of about 0.3 micro seconds. The second period, lasting at least 50 micro seconds, has a characteristic decay time of about 5 micro seconds. These characteristic times are thought to be associated with cooling of C60 molecules or nanosized carbon particles during the early period; and with electronically excited C2 that is a decomposition product of laser excited C60, C58, ... molecules during the later period.

  2. Physiological effects of the TASER C2 conducted energy weapon.

    Science.gov (United States)

    Jauchem, James R; Seaman, Ronald L; Klages, Curtis M

    2009-01-01

    In previous studies, exposure to conducted energy weapons (CEWs) (such as TASER International's Advanced TASER X26 device) resulted in leg muscle contraction, acidosis, increased blood electrolytes, and other biochemical and physiological changes. In the current study, experiments were performed to examine the effects of exposures to TASER International's "C2" CEW, which is specifically marketed to civilian rather than law-enforcement users. Ten pigs (Sus scrofa) were sedated with an intramuscular injection of Telezol (tiletamine HCl and zolazepam HCl) and intubated. General anesthesia was maintained with an IV propofol infusion. Applications of the C2 device for 30 s resulted in extensive muscle contraction and significant increases in heart rate and hematocrit, and in blood levels of pCO2, lactate, glucose, and potassium, sodium, and calcium ions. Significant decreases were observed in blood oxygen saturation, pO2, and pH. Qualitatively, many of these changes were consistent with previous reports in the literature dealing with studies of muscle stimulation or exercise. The changes in blood pCO2, pO2, electrolytes, lactate, and pH, however, were greater than in a previous study of three repeated 5-s exposures to the X26 CEW commonly used by law-enforcement personnel. On the basis of the results, potential detrimental effects due to use of the "citizen-version" TASER C2 CEW may be more likely than limited intermittent applications of the X26 CEW.

  3. Toxicity tests on native and recombinant Bordetella pertussis adenylate cyclase toxin preparations.

    Science.gov (United States)

    Hormozi, K; Parton, R; Coote, J

    1999-01-01

    Bordetella pertussis produces a cell-invasive adenylate cyclase toxin which is synthesised from the cyaA gene as an inactive protoxin that is post-translationally activated by the product of the cyaC gene. Active and inactive CyaA proteins were prepared in crude and purified form from B. pertussis or from recombinant E. coli expressing both cyaA and cyaC genes or the cyaA gene alone, respectively. The specific AC activities of all the crude or all the purified toxins were similar. The toxins produced in the absence of CyaC activity had no cell invasive, haemolytic or cytotoxic activity. The cell invasive and cytotoxic activities of native and recombinant active CyaA preparations were similar, but the haemolytic activity of the recombinant toxin was lower than that of the native protein. As part of mouse protection tests, mice were injected subcutaneously with 15 microg per mouse of crude or purified CyaA preparations plus alhydrogel or with 1/5 human dose of adsorbed DPT vaccine (Wellcome Trivax-AD) using two doses at a two week interval. Control groups of mice were injected with alhydrogel in PBS alone or left unvaccinated. The toxin preparations had little or no effect on mouse weight gain, and there were no marked differences between mice vaccinated with the active toxin and those given the inactive form. Thus, at the dose used, there was no clear toxic physiological response caused specifically by active CyaA.

  4. Variable Virulence of Biotype 3 Vibrio vulnificus due to MARTX Toxin Effector Domain Composition.

    Science.gov (United States)

    Kim, Byoung Sik; Gavin, Hannah E; Satchell, Karla J F

    2017-01-01

    Vibrio vulnificus is an environmental organism that causes septic human infections characterized by high morbidity and mortality. The annual incidence and global distribution of this pathogen are increasing as ocean waters warm. Clinical strains exhibit variations in the primary virulence toxin, suggesting a potential for the emergence of new strains with altered virulence properties. A clonal outbreak of tilapia-associated wound infections in Israel serves as a natural experiment for the sudden emergence of a new V. vulnificus strain. The effector domain content of the multifunctional autoprocessing RTX (MARTX) toxin of the outbreak-associated biotype 3 (BT3) strains was previously shown to harbor a modification generated by recombination. The modification introduced an actin-induced adenylate cyclase effector domain (ExoY) and an effector domain that disrupts the Golgi organelle (DmX). Here, we report that the exchange of these effector domains for a putative progenitor biotype 1 toxin arrangement produces a toxin that slows the lysis kinetics of targeted epithelial cells but increases cellular rounding phenotypes in response to bacteria. In addition, replacing the biotype 3 toxin variant with the putative progenitor biotype 1 variant renders the resulting strain significantly more virulent in mice. This suggests that the exchange of MARTX effector domains during the emergence of BT3 generated a toxin with reduced toxin potency, resulting in decreased virulence of this outbreak-associated strain. We posit that selection for reduced virulence may serve as a route for this lethal infectious agent to enter the human food chain by allowing it to persist in natural hosts. IMPORTANCEVibrio vulnificus is a serious infection linked to climate change. The virulence capacity of these bacteria can vary by gene exchange, resulting in new variants of the primary virulence toxin. In this study, we tested whether the emergence of an epidemic strain of V. vulnificus with a

  5. Nutrition affects insect susceptibility to Bt toxins

    Science.gov (United States)

    Deans, Carrie A.; Behmer, Spencer T.; Tessnow, Ashley E.; Tamez-Guerra, Patricia; Pusztai-Carey, Marianne; Sword, Gregory A.

    2017-01-01

    Pesticide resistance represents a major challenge to global food production. The spread of resistance alleles is the primary explanation for observations of reduced pesticide efficacy over time, but the potential for gene-by-environment interactions (plasticity) to mediate susceptibility has largely been overlooked. Here we show that nutrition is an environmental factor that affects susceptibility to Bt toxins. Protein and carbohydrates are two key macronutrients for insect herbivores, and the polyphagous pest Helicoverpa zea self-selects and performs best on diets that are protein-biased relative to carbohydrates. Despite this, most Bt bioassays employ carbohydrate-biased rearing diets. This study explored the effect of diet protein-carbohydrate content on H. zea susceptibility to Cry1Ac, a common Bt endotoxin. We detected a 100-fold increase in LC50 for larvae on optimal versus carbohydrate-biased diets, and significant diet-mediated variation in survival and performance when challenged with Cry1Ac. Our results suggest that Bt resistance bioassays that use ecologically- and physiologically-mismatched diets over-estimate susceptibility and under-estimate resistance.

  6. Overlooked Short Toxin-Like Proteins: A Shortcut to Drug Design

    Directory of Open Access Journals (Sweden)

    Michal Linial

    2017-10-01

    Full Text Available Short stable peptides have huge potential for novel therapies and biosimilars. Cysteine-rich short proteins are characterized by multiple disulfide bridges in a compact structure. Many of these metazoan proteins are processed, folded, and secreted as soluble stable folds. These properties are shared by both marine and terrestrial animal toxins. These stable short proteins are promising sources for new drug development. We developed ClanTox (classifier of animal toxins to identify toxin-like proteins (TOLIPs using machine learning models trained on a large-scale proteomic database. Insects proteomes provide a rich source for protein innovations. Therefore, we seek overlooked toxin-like proteins from insects (coined iTOLIPs. Out of 4180 short (<75 amino acids secreted proteins, 379 were predicted as iTOLIPs with high confidence, with as many as 30% of the genes marked as uncharacterized. Based on bioinformatics, structure modeling, and data-mining methods, we found that the most significant group of predicted iTOLIPs carry antimicrobial activity. Among the top predicted sequences were 120 termicin genes from termites with antifungal properties. Structural variations of insect antimicrobial peptides illustrate the similarity to a short version of the defensin fold with antifungal specificity. We also identified 9 proteins that strongly resemble ion channel inhibitors from scorpion and conus toxins. Furthermore, we assigned functional fold to numerous uncharacterized iTOLIPs. We conclude that a systematic approach for finding iTOLIPs provides a rich source of peptides for drug design and innovative therapeutic discoveries.

  7. The rate of the reaction between C2H and C2H2 at interstellar temperatures

    Science.gov (United States)

    Herbst, E.; Woon, D. E.

    1997-01-01

    The reaction between the radical C2H and the stable hydrocarbon C2H2 is one of the simplest neutral-neutral hydrocarbon reactions in chemical models of dense interstellar clouds and carbon-rich circumstellar shells. Although known to be rapid at temperatures > or = 300 K, the reaction has yet to be studied at lower temperatures. We present here ab initio calculations of the potential surface for this reaction and dynamical calculations to determine its rate at low temperature. Despite a small potential barrier in the exit channel, the calculated rate is large, showing that this reaction and, most probably, more complex analogs contribute to the formation of complex organic molecules in low-temperature sources.

  8. Theoretical study on the rate constants for the C2H5 + HBr --> C2H6 + Br reaction.

    Science.gov (United States)

    Sheng, Li; Li, Ze-Sheng; Liu, Jing-Yao; Xiao, Jing-Fa; Sun, Chia-Chung

    2004-02-01

    The reaction C(2)H(5) + HBr --> C(2)H(6) + Br has been theoretically studied over the temperature range from 200 to 1400 K. The electronic structure information is calculated at the BHLYP/6-311+G(d,p) and QCISD/6-31+G(d) levels. With the aid of intrinsic reaction coordinate theory, the minimum energy paths (MEPs) are obtained at the both levels, and the energies along the MEP are further refined by performing the single-point calculations at the PMP4(SDTQ)/6-311+G(3df,2p)//BHLYP and QCISD(T)/6-311++G(2df,2pd)//QCISD levels. The calculated ICVT/SCT rate constants are in good agreement with available experimental values, and the calculate results further indicate that the C(2)H(5) + HBr reaction has negative temperature dependence at T 850 K. The current work predicts that the kinetic isotope effect for the title reaction is inverse in the temperature range from 200 to 482 K, i.e., k(HBr)/k(DBr) < 1. Copyright 2003 Wiley Periodicals, Inc.

  9. Evaluation of antidiphtheria toxin nanobodies

    Directory of Open Access Journals (Sweden)

    Ghada H Shaker

    2010-06-01

    Full Text Available Ghada H ShakerDepartment of Microbiology and Immunology, Faculty of Pharmacy, King Saud University, Riyadh, Kingdom of Saudi ArabiaAbstract: Nanobodies are the smallest fragments of naturally occurring single-domain antibodies that have evolved to be fully functional in the absence of a light chain. Conventional antibodies are glycoproteins comprising two heavy and two light chains. Surprisingly, all members of the Camelidae family possess a fraction of antibodies devoid of both light chains and the first constant domain. These types of antibodies are known as heavy-chain antibody (HcAb nanobodies. There are three subclasses of IgG in dromedaries, namely IgG1, IgG2, and IgG3 of which IgG2 and IgG3 are of the HcAb type. These heavy chain antibodies constitute approximately 50% of the IgG in llama serum and as much as 75% of the IgG in camel serum. In the present work, the different IgG subclasses from an immunized camel (Camelus dromedarius with divalent diphtheria-tetanus vaccine were purified using their different affinity for protein A and protein G and their absorbance measured at 280 nm. Purity control and characterization by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis of IgG subclasses was done under reducing conditions. Protein bands were visualized after staining with Coomassie Blue, showing two bands at 50 kDa and 30 kDa for IgG1, while IgG2 and IgG3 produced only one band at 46 kDa and 43 kDa, respectively. An enzyme-linked immunosorbent assay test using diphtheria toxin and purified IgG subclasses from the immunized camel were performed to evaluate their efficiency. Compared with conventional IgG1, heavy chain antibodies (nanobodies were shown to be more efficient in binding to diphtheria toxin antigen. This study revealed the possibility of using IgG2 and IgG3 nanobodies as an effective antitoxin for the treatment of diphtheria in humans.Keywords: camel, heavy chain antibody, HcAb, nanobodies, immunoglobulin, Ig

  10. Sarcolipin expression is repressed by endoplasmic reticulum stress in C2C12 myotubes.

    Science.gov (United States)

    Takahashi, Nobuhiko; Kimura, Atsushi P; Naito, Sumiyoshi; Yoshida, Mika; Kumano, Osamu; Suzuki, Takeshi; Itaya, Satoshi; Moriya, Mitsuru; Tsuji, Masahiro; Ieko, Masahiro

    2017-11-01

    Sarcolipin is a transmembrane protein expressed in the sarco/endoplasmic reticulum of skeletal and atrial muscles in large animals. Sarcolipin plays crucial roles in heat production through modifying the function of sarco/endoplasmic reticulum Ca2+ ATPase, thereby being involved in thermogenesis and systemic metabolism. In skeletal muscle, endoplasmic reticulum (ER) stress has been implicated in several conditions, such as insulin resistance, muscle diseases, and hypo/hyper-contraction. Here, we investigated the effect of ER stress on sarcolipin expression in skeletal muscle cells, C2C12 myotubes. First, gene expression of sarcolipin was confirmed in the cells during myogenesis. Then, ER stress was induced in C2C12 myotubes by treatment with tunicamycin or thapsigargin. Sarcolipin messenger RNA (mRNA) and protein expression were significantly reduced by ER stress induction. The reduction was independent of inositol-requiring element 1 (IRE1), which is activated by ER stress and has potent endonuclease activity, when evaluated by treatment with an IRE1 inhibitor, 4μ8C. On the other hand, sarcolipin mRNA stability was reduced under the ER stress when evaluated by treatment with actinomycin D. In conclusion, these results show that ER stress represses sarcolipin expression due to changes in mRNA stability in C2C12 myotubes.

  11. Identification of a VapBC toxin-antitoxin system in a thermophilic bacterium Thermus thermophilus HB27.

    Science.gov (United States)

    Fan, Yuqi; Hoshino, Takayuki; Nakamura, Akira

    2017-01-01

    There are 12 putative toxin-antitoxin (TA) loci in the Thermus thermophilus HB27 genome, including four VapBC and three HicBA families. Expression of these seven putative toxin genes in Escherichia coli demonstrated that one putative VapC toxin TTC0125 and two putative HicA toxins, TTC1395 and TTC1705, inhibited cell growth, and co-expression with cognate antitoxin genes rescued growth, indicating that these genes function as TA loci. In vitro analysis with the purified TTC0125 and total RNA/mRNA from E. coli and T. thermophilus showed that TTC0125 has RNase activity to rRNA and mRNA; this activity was inhibited by the addition of the purified TTC0126. Translation inhibition assays showed that TTC0125 inhibited protein synthesis by degrading mRNA but not by inactivating ribosomes. Amino acid substitutions of 14 predicted catalytic and conserved residues in VapC toxins to Ala or Asp in TTC0125 indicated that nine residues are important for its in vivo toxin activity and in vitro RNase activity. These data demonstrate that TTC0125-TTC0126 functions as a VapBC TA module and causes growth inhibition by degrading free RNA. This is the first study to identify the function of TA systems in T. thermophilus.

  12. Production of exfoliative toxin by isolates of Staphylococcus hyicus from different countries

    DEFF Research Database (Denmark)

    Andresen, Lars Ole

    2005-01-01

    A total of 218 isolates of Staphylococcus hyicus from pigs in eight countries (Belgium, Croatia, Germany, Japan, Korea, Slovenia, the UK and the USA) and 44 isolates from other animals in Belgium, India, Japan and the USA were examined for the genes encoding the exfoliative toxins ExhA, ExhB, Exhc...

  13. Relevance of Bt toxin interaction studies for environmental risk assessment of genetically modified crops

    NARCIS (Netherlands)

    Schrijver, De Adinda; Clercq, De Patrick; Maagd, de R.A.; Frankenhuyzen, van Kees

    2015-01-01

    In recent years, different Bacillus thuringiensis (Bt) toxin-encoding genes have been combined or 'stacked' in genetically modified (GM) crops. Synergism between Bt proteins may occur and thereby increase the impact of the stacked GM event on nontarget invertebrates compared to plants expressing

  14. NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens.

    Directory of Open Access Journals (Sweden)

    Anthony L Keyburn

    2008-02-01

    Full Text Available For over 30 years a phospholipase C enzyme called alpha-toxin was thought to be the key virulence factor in necrotic enteritis caused by Clostridium perfringens. However, using a gene knockout mutant we have recently shown that alpha-toxin is not essential for pathogenesis. We have now discovered a key virulence determinant. A novel toxin (NetB was identified in a C. perfringens strain isolated from a chicken suffering from necrotic enteritis (NE. The toxin displayed limited amino acid sequence similarity to several pore forming toxins including beta-toxin from C. perfringens (38% identity and alpha-toxin from Staphylococcus aureus (31% identity. NetB was only identified in C. perfringens type A strains isolated from chickens suffering NE. Both purified native NetB and recombinant NetB displayed cytotoxic activity against the chicken leghorn male hepatoma cell line LMH; inducing cell rounding and lysis. To determine the role of NetB in NE a netB mutant of a virulent C. perfringens chicken isolate was constructed by homologous recombination, and its virulence assessed in a chicken disease model. The netB mutant was unable to cause disease whereas the wild-type parent strain and the netB mutant complemented with a wild-type netB gene caused significant levels of NE. These data show unequivocally that in this isolate a functional NetB toxin is critical for the ability of C. perfringens to cause NE in chickens. This novel toxin is the first definitive virulence factor to be identified in avian C. perfringens strains capable of causing NE. Furthermore, the netB mutant is the first rationally attenuated strain obtained in an NE-causing isolate of C. perfringens; as such it has considerable vaccine potential.

  15. Differences in chimera formation and germline transmission between E14 and C2J embryonic stem cells in mice.

    Science.gov (United States)

    Zhu, Yan; Li, Dun-Gao; Sun, Zhao-Gui; Chen, Xue-Jin; Jiang, Man-Xi

    2014-05-01

    Summary The goal of this project was to determine whether the originating strain of mouse embryonic stem (ES) cells affects the maintenance of their pluripotency under uniform culture conditions. ES cells from two strains of mice, E14 and C2J, were tested. Both ES cell lines were cultured in KOSR + 2i medium and then injected into C57BL/6J blastocysts. Our results demonstrate that this medium could support both E14 and C2J ES cells to keep their pluripotency, though E14 ES cells were found to have a higher chimeric rate than C2J ES cells. However, analysis by backcrossing revealed that C2J and E14 ES cells have the same ability for germline transmission. Our results demonstrate that ES cells derived from E14 and C2J cells have the same capacity for germline transmission when injected into C57BL/6J blastocysts; however, due to the limitation of mixed genetic background between E14 cells and host C57BL/6J embryos, C2J ES cells are preferable to E14 ES cells for use in gene-targeting and should become the cell line of choice for the generation of genetically engineered mutant mouse lines.

  16. Botulinum toxin for the treatment of bruxism.

    Science.gov (United States)

    Tinastepe, Neslihan; Küçük, Burcu Bal; Oral, Koray

    2015-10-01

    Botulinum toxin, the most potent biological toxin, has been shown to be effective for a variety of disorders in several medical conditions, when used both therapeutically and cosmetically. In recent years, there has been a rising trend in the use of this pharmacological agent to control bruxing activity, despite its reported adverse effects. The aim of this review was to provide a brief overview to clarify the underlying essential ideas for the use of botulinum toxin in bruxism based on available scientific papers. An electronic literature search was performed to identify publications related to botulinum toxin and its use for bruxism in PubMed. Hand searching of relevant articles was also made to identify additional studies. Of the eleven identified studies, only two were randomized controlled trials, compared with the effectiveness of botulinum toxins on the reduction in the frequency of bruxism events and myofascial pain after injection. The authors of these studies concluded that botulinum toxin could be used as an effective treatment for reducing nocturnal bruxism and myofascial pain in patients with bruxism. Evidence-based research was limited on this topic. More randomized controlled studies are needed to confirm that botulinum toxin is safe and reliable for routine clinical use in bruxism.

  17. Interplay between toxin transport and flotillin localization.

    Directory of Open Access Journals (Sweden)

    Sascha Pust

    Full Text Available The flotillin proteins are localized in lipid domains at the plasma membrane as well as in intracellular compartments. In the present study, we examined the importance of flotillin-1 and flotillin-2 for the uptake and transport of the bacterial Shiga toxin (Stx and the plant toxin ricin and we investigated whether toxin binding and uptake were associated with flotillin relocalization. We observed a toxin-induced redistribution of the flotillins, which seemed to be regulated in a p38-dependent manner. Our experiments provide no evidence for a changed endocytic uptake of Stx or ricin in cells silenced for flotillin-1 or -2. However, the Golgi-dependent sulfation of both toxins was significantly reduced in flotillin knockdown cells. Interestingly, when the transport of ricin to the ER was investigated, we obtained an increased mannosylation of ricin in flotillin-1 and flotillin-2 knockdown cells. The toxicity of both toxins was twofold increased in flotillin-depleted cells. Since BFA (Brefeldin A inhibits the toxicity even in flotillin knockdown cells, the retrograde toxin transport is apparently still Golgi-dependent. Thus, flotillin proteins regulate and facilitate the retrograde transport of Stx and ricin.

  18. C2-rational cubic spline involving tension parameters

    Indian Academy of Sciences (India)

    iИ1 ИfЕ122Y 128Ж; Е122Y 156Ж; Е150Y 184Ж; Е178Y 184Ж;. Е206Y 156Ж; Е206Y 128Ж; Е178Y 100Ж; Е150Y 100Ж;. Е122Y 72Ж; Е122Y 44Ж; Е150Y 16Ж; Е178Y 16Ж;. Е206Y 44Ж; Е206Y 72ЖgY we obtain the C2-rational cubic spline interpolant. Thus for different values of the tension parameters r and t, ...

  19. C2-domain containing calcium sensors in neuroendocrine secretion

    DEFF Research Database (Denmark)

    Pinheiro, Paulo S; Houy, Sébastien; Sørensen, Jakob B

    2016-01-01

    to calcium, trigger the merger of cargo-filled vesicles with the plasma membrane. Low-affinity, fast-kinetics calcium sensors of the synaptotagmin family - especially synaptotagmin-1 and synaptotagmin-2 - are the main calcium sensors for fast exocytosis triggering in many cell types. Their functions extend...... the properties and possible interplay of (some of) the major C2-domain containing calcium sensors in calcium-triggered exocytosis. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases"....

  20. Near-Infrared Spectroscopy of Ethynyl Radical, C2H

    Science.gov (United States)

    Le, Anh T.; Hall, Gregory; Sears, Trevor

    2016-06-01

    The ethynyl radical, C_2H, is a reactive intermediate important in various combustion processes and also widely observed in the interstellar medium. In spite of extensive previous spectroscopic studies, the characterization of the near infrared transitions from the tilde{X}2Σ+ state to the mixed vibrational overtone and tilde{A}2Π states is incomplete. A strong band of C_2H at 7064 cm-1 was first observed in a neon matrix and assigned as the tilde{A}2Π(002)1 - tilde{X}2Σ+ transition by Forney et al. Subsequent theoretical work of Tarroni and Carter attributed the strong absorptions in this region to transitions terminating in two upper states, each a mixture of vibrationally excited tilde{X} states and different zero-order tilde{A}-state bending levels: a 2Σ+ symmetry combination of tilde{X}(0,20,3) and tilde{A}(0,3,0)0κ and a 2Π symmetry combination of tilde{X}(0,31,3) and tilde{A}(0,0,2)1. Transitions to them from the zero point level of the tilde{X} state are calculated to differ in energy by less than 10 cm-1 and to be within a factor of two in intensity. Diode laser transient absorption was used to record Doppler-limited spectra between 7020 and 7130 cm-1, using 193 nm photolysis of CF_3C_2H as a source of C_2H. Two interleaved, rotationally resolved bands were observed, consistent with a 2Σ - 2Σ transition at 7088 cm-1 and a 2Π - 2Σ transition at 7108 cm-1, in good accord with the Tarroni and Carter calculation. Progress on the assignment and fitting of the spectra will be reported. Acknowledgements: Work at Brookhaven National Laboratory was carried out under Contract No. DE-SC0012704 with the U.S. Department of Energy, Office of Science, and supported by its Division of Chemical Sciences, Geosciences, and Biosciences. D. Forney, M.E. Jacox, and W.E. Thompson, J. Mol. Spectrosc. 170, 178 (1995). R. Tarroni and S. Carter, Mol. Phys. 102, 2167 (2004)

  1. [(i-Bu2NH22C2O4]4.SnPh2C2O4.C2O4(SnPh32 and [(i-Bu2NH2 2C2O4]3.SnBu2C2O4: SYNTHESIS, INFRARED AND MOSSBAUER STUDIES

    Directory of Open Access Journals (Sweden)

    YAYA SOW

    2015-02-01

    Full Text Available [(i-Bu2NH22C2O4]4.SnPh2C2O4.C2O4(SnPh32 and [(i-Bu2NH22C2O4]3. SnBu2C2O4 have been synthesized and characterized by infrared and Mossbauer spectroscopies. The suggested structure are discrete (one being a two metallic components, the environments around the tin(IV centres being octahedral and pentagonal bipyramidal, the oxalate anions being monodentate, the cations linking through N-H….O hydrogen bonds the free oxygen atoms of the oxalate. The second metallic component of one of the structures is cis coordinated C2O4(SnPh32.

  2. Polymorphic toxin systems: Comprehensive characterization of trafficking modes, processing, mechanisms of action, immunity and ecology using comparative genomics

    Directory of Open Access Journals (Sweden)

    Zhang Dapeng

    2012-06-01

    Full Text Available Abstract Background Proteinaceous toxins are observed across all levels of inter-organismal and intra-genomic conflicts. These include recently discovered prokaryotic polymorphic toxin systems implicated in intra-specific conflicts. They are characterized by a remarkable diversity of C-terminal toxin domains generated by recombination with standalone toxin-coding cassettes. Prior analysis revealed a striking diversity of nuclease and deaminase domains among the toxin modules. We systematically investigated polymorphic toxin systems using comparative genomics, sequence and structure analysis. Results Polymorphic toxin systems are distributed across all major bacterial lineages and are delivered by at least eight distinct secretory systems. In addition to type-II, these include type-V, VI, VII (ESX, and the poorly characterized “Photorhabdus virulence cassettes (PVC”, PrsW-dependent and MuF phage-capsid-like systems. We present evidence that trafficking of these toxins is often accompanied by autoproteolytic processing catalyzed by HINT, ZU5, PrsW, caspase-like, papain-like, and a novel metallopeptidase associated with the PVC system. We identified over 150 distinct toxin domains in these systems. These span an extraordinary catalytic spectrum to include 23 distinct clades of peptidases, numerous previously unrecognized versions of nucleases and deaminases, ADP-ribosyltransferases, ADP ribosyl cyclases, RelA/SpoT-like nucleotidyltransferases, glycosyltranferases and other enzymes predicted to modify lipids and carbohydrates, and a pore-forming toxin domain. Several of these toxin domains are shared with host-directed effectors of pathogenic bacteria. Over 90 families of immunity proteins might neutralize anywhere between a single to at least 27 distinct types of toxin domains. In some organisms multiple tandem immunity genes or immunity protein domains are organized into polyimmunity loci or polyimmunity proteins. Gene-neighborhood-analysis of

  3. Targeting diphtheria toxin and TNF alpha expression in ovarian tumors using the H19 regulatory sequences

    Science.gov (United States)

    Mizrahi, Aya; Hochberg, Abraham; Amiur, Smadar; Gallula, Jennifer; Matouk, Imad; Birman, Tatiana; Levy, Tally; ladimir, Sorin; Ohana, Patricia

    2010-01-01

    Background: There are currently no effective therapies for the treatment of ovarian cancer ascites fluid (OCAF). H19 is an RNA oncofetal gene that is present at high levels in human cancer tissues (ovarian cancer and OCAF among them), while existing at a nearly undetectable level in the surrounding normal tissue. There is evidence for a synergistic effect in cell cytotoxicity mediated by TNFα and diphtheria toxin in sensitive and resistant human ovarian tumor cell line. Thus, we tested the cytotoxic effect of TNF-α cytokine, together with the diphtheria toxin, in the therapy of ovarian cancer. Methods: The therapeutic potential of toxin vectors carrying the DT-A gene alone (pH19-DTA), or in combination with the TNF-α gene (pH19-TNF-DTA), driven by H19 regulatory sequences were tested in ovarian carcinoma cell lines and in a heterotopic ovarian cancer model. Results: The toxin vectors showed a high killing capacity when transfected into different ovarian cancer cell lines. In addition, intratumoral injection of the toxin vector into ectopically developed tumors caused 40% inhibition of tumor growth. The killing effect after injection of pH19-TNF-DTA plasmid into ectopically developed tumors was significantly higher than that showed by the pH19-DTA plasmid alone, particularly in diphtheria toxin and TNF resistant tumors. Conclusions: These observations may be the first step towards a major breakthrough in the treatment of human ovarian cancer. It should enable us to identify likely non-responders in advance, and to treat patients who are resistant to all known therapies, thereby avoiding treatment failure coupled with unnecessary suffering and cost. PMID:21072261

  4. Fibroblast Growth Factor 21 Promotes C2C12 Cells Myogenic Differentiation by Enhancing Cell Cycle Exit

    Directory of Open Access Journals (Sweden)

    Xinyi Liu

    2017-01-01

    Full Text Available Fibroblast growth factor 21 (FGF21, a secretion protein, functions as a pivotal regulator of energy metabolism and is being considered as a therapeutic candidate in metabolic syndromes. However, the roles of FGF21 in myogenic differentiation and cell cycle remain obscure. In this study, we investigated the function of FGF21 in myogenesis and cell cycle exit using C2C12 cell line. Our data showed that the expression of myogenic genes as well as cell cycle exit genes was increased after FGF21 overexpression, and FGF21 overexpression induces cell cycle arrest. Moreover, cell cycle genes were decreased in FGF21 overexpression cells while they were increased in FGF21 knockdown cells. Further, FGF21/P53/p21/Cyclin-CDK has been suggested as the key pathway for cell cycle exit mediated by FGF21 in C2C12 cells. Also, we deduce that FGF21 promotes the initiation of myogenic differentiation mainly through enhancing cell cycle exit of C2C12 cells. Taken together, our results demonstrated that FGF21 promotes cell cycle exit and enhances myogenic differentiation of C2C12 cells. This study provided new evidence that FGF21 promotes myogenic differentiation, which could be useful for better understanding the roles of FGF21 in myogenesis.

  5. Development of Compact Toroid Injector for C-2 FRCs

    Science.gov (United States)

    Matsumoto, Tadafumi; Sekiguchi, Junichi; Asai, Tomohiko; Gota, Hiroshi; Garate, Eusebio; Allfrey, Ian; Valentine, Travis; Smith, Brett; Morehouse, Mark; TAE Team

    2014-10-01

    Collaborative research project with Tri Alpha Energy has been started and we have developed a new compact toroid (CT) injector for the C-2 device, mainly for fueling field-reversed configurations (FRCs). The CT is formed by a magnetized coaxial plasma-gun (MCPG), which consists of coaxial cylinder electrodes; a spheromak-like plasma is generated by discharge and pushed out from the gun by Lorentz force. The inner diameter of outer electrode is 83.1 mm and the outer diameter of inner electrode is 54.0 mm. The surface of the inner electrode is coated with tungsten in order to reduce impurities coming out from the electrode. The bias coil is mounted inside of the inner electrode. We have recently conducted test experiments and achieved a supersonic CT translation speed of up to ~100 km/s. Other typical plasma parameters are as follows: electron density ~ 5 × 1021 m-3, electron temperature ~ 40 eV, and the number of particles ~0.5-1.0 × 1019. The CT injector is now planned to be installed on C-2 and the first CT injection experiment will be conducted in the near future. The detailed MCPG design as well as the test experimental results will be presented.

  6. Characterization of the C-2W Plasma Guns

    Science.gov (United States)

    Dubois, Ami; Sokolov, Vladimir; Korepanov, Sergey; Osin, Dima; Player, Gabriel; TAE Team

    2017-10-01

    Previous use of coaxial arc discharge plasma guns on the C-2U device exhibited great success in plasma stabilization and improved confinement. On the C-2W experiment, arc discharge plasma guns will again be used to facilitate the electrical connection between the plasma core and the divertor electrodes in order to maintain the electrode edge biasing and induce E x B shear to control plasma rotation. Each plasma gun contains an internal solenoid used to shape the plasma stream. Characterization of electron density (ne) , electron temperature (Te) , floating potential (Vf) , and total plasma flux in an arc discharge lasting 6 ms without the internal solenoid are presented. A Langmuir probe located 27 cm axially outside of the plasma gun anode measures a bell-like radial ne profile with peak ne 1018 m-3 and Te 2 - 10 eV. Observed spectral lines of impurity ions provide an estimate of Te, and Balmer series line ratios of the main ion component are used to evaluate ne at both the probe location and near the plasma gun anode. A calorimeter measures the plasma flux to be constant and equivalent to 1 kA.

  7. Characteristics of Shiga Toxin-Producing Escherichia coli O157 in Slaughtered Reindeer from Northern Finland.

    Science.gov (United States)

    Zweifel, Claudio; Fierz, Lisa; Cernela, Nicole; Laaksonen, Sauli; Fredriksson-Ahomaa, Maria; Stephan, Roger

    2017-03-01

    Fecal samples collected from 470 slaughtered reindeer 6 to 7 months of age were screened by real-time PCR (after enrichment) for Shiga toxin genes (stx) and then for Escherichia coli serogroup O157. Shiga toxin genes were found frequently (>30% of samples), and serogroup O157 was detected in 20% of the stx-positive samples. From these samples, a total of 25 E. coli O157:H - isolates (nonmotile but PCR positive for fliC H7 ) were obtained. Twenty-four of these E. coli O157:H - isolates did not ferment sorbitol and originated from one geographic area. These 24 isolates belonged to the multilocus sequence type 11, typical for Shiga toxin-producing E. coli (STEC) O157:H7 and O157:H - , and harbored genes stx 1a , stx 2c , eae, and hlyA; the stx 2c subtype has been associated with high virulence. In contrast, one E. coli O157:H - isolate (multilocus sequence type 11) did ferment sorbitol, lacked Shiga toxin genes, but was positive for eae, hlyA, and sfpA. This isolate closely resembled an STEC that has lost its Shiga toxin genes. Additional examination revealed that reindeer can be colonized by various other STEC isolates; 21 non-O157 STEC isolates belonged to four multilocus sequence types, harbored stx 1a (8 isolates) or stx 2b (13 isolates), and in the stx 2b -positive isolates the recently described new allelic variants (subAB2-2 and subAB2-3) for subtilase cytotoxin were identified. Hence, slaughtered semidomesticated Finnish reindeer might constitute a little known reservoir for STEC O157:H7/H - and other serogroups, and the risk of direct or indirect transmission of these pathogens from reindeer to humans and domestic livestock must not be overlooked.

  8. Retrograde transport of protein toxins through the Golgi apparatus

    DEFF Research Database (Denmark)

    Sandvig, Kirsten; Skotland, Tore; van Deurs, Bo

    2013-01-01

    A number of protein toxins from plants and bacteria take advantage of transport through the Golgi apparatus to gain entry into the cytosol where they exert their action. These toxins include the plant toxin ricin, the bacterial Shiga toxins, and cholera toxin. Such toxins bind to lipids or proteins...... at the cell surface, and they are endocytosed both by clathrin-dependent and clathrin-independent mechanisms. Sorting to the Golgi and retrograde transport to the endoplasmic reticulum (ER) are common to these toxins, but the exact mechanisms turn out to be toxin and cell-type dependent. In the ER......, the enzymatically active part is released and then transported into the cytosol, exploiting components of the ER-associated degradation system. In this review, we will discuss transport of different protein toxins, but we will focus on factors involved in entry and sorting of ricin and Shiga toxin into and through...

  9. Comparison of enzyme immunoassays and rapid diagnostic tests for clostridium difficile glutamate dehydrogenase and toxin a + B to toxinogenic culture on a highly selective chromogenic medium.

    Science.gov (United States)

    Olling, A; Leidinger, H; Hoffmann, R

    2016-10-01

    To compare Clostridium. (C.) difficile toxin A/B and glutamate dehydrogenase (GDH) enzyme immunoassays or rapid diagnostic tests to toxinogenic culture on recently described highly selective agar plates. Five hundred consecutive samples sent in for C. difficile diagnostics were tested by toxin A/B enzyme immunoassay (EIA) and rapid diagnostic test (RDT), GDH EIA and RDT, and culture on chromID C. difficile plates for 48 hrs, with toxin testing from culture if the toxin EIA from feces was negative. Samples with discordant results from EIA and RDT were submitted to C. difficile-specific 16S rRNA gene and tcdB PCR. Ninety-two, 88, 31, and 37 samples were positive by GDH EIA, GDH RDT, toxin A/B EIA, and toxin A/B RDT respectively. Seventy-four samples were positive by culture, 54 culture-positive samples were subjected to repeat toxin testing, with an additional 29 samples positive. Thus, there were 60 C. difficile toxin A/B positive samples in total (12 %). Single-step screening with GDH EIA, GDH RDT, toxin A/B EIA, and toxin A/B RDT would have missed seven (12 %), 11 (18 %), 29 (48 %) or 27 (45 %) of all positive samples respectively. Single-step screening with GDH or toxin A/B tests from feces misses a significant proportion of patients compared to toxinogenic culture, putting these patients at risk from undiagnosed C. difficile infection. More data are needed to establish the clinical significance of a positive toxinogenic culture result in the absence of detectable toxin A/B in feces.

  10. Amino-acid sequence of a coelenterate toxin: toxin II from Anemonia sulcata.

    Science.gov (United States)

    Wunderer, G; Fritz, H; Wachter, E; Machleidt, W

    1976-09-01

    Toxin II from Anemonia sulcata, the main component of the sea anemone venom, consists of 47 amino acid residues which are interconnected by three disulfide bridges. The S-aminoethylated polypeptide was coupled to activated glass beads and sequenced to position 33 by automated solid-phase Edman degradation. Blanks arising from anchor points and the rest of the sequence were determined from tryptic peptides of the [14C]carboxymethylated toxin. Toxin II shows no significant homologies with other known sequences of neurotoxins or cardiotoxins. It might constitute a new class of polypeptide toxins.

  11. Shiga-Like Toxin 2 of Enterohemorrhagic Escherichia Coli (EHEC): Genetic Organization and Effects of Toxin in a Murine Model of EHEC Infection

    Science.gov (United States)

    1990-04-27

    Shiga toxin of Shigella dysenteriae type 1. Shiga toxin has been recognized as one of the most potent bacterial toxins for eucaryotic cells . Shiga toxin...Shiga toxin transcription or the efficiency of toxin release from the bacterial cell . IV SHIGA-LIKE TOXIN TYPE 11 OF ENTEROHEMORRHAGIC...2 rabbits (Conradi, 1903). Subsequent reports demonstrated that crude prepara- tions of Shiga toxin were cytotoxic for selected mammalian cells

  12. INVESTIGATOIN OF CYANOBACTERIA TOXINS IN WATER

    Science.gov (United States)

    Introduction:Approximately 80 alkaloid and cyclic peptide toxins produced by various freshwater and marine cyanobacteria (blue-green algae) have been identified and their structures determined. The U. S. Environmental Protection Agency has identified two neurotoxin alkalo...

  13. Peptide toxin components of Amanita exitialis basidiocarps

    National Research Council Canada - National Science Library

    Wang-Qiu Deng; Tai-Hui Li; Ping-Gen Xi; Li-Xia Gan; Zheng-Duan Xiao; Zi-De Jiang

    2011-01-01

    .... The molecular weight (729.5 Da) of the eighth compound did not match that of any reported Amanita toxins and, although the UV absorption spectrum indicated it to be a phallotoxin, further studies are required to identify this component...

  14. Bacterial toxins as pathogen weapons against phagocytes

    Directory of Open Access Journals (Sweden)

    Ana edo Vale

    2016-02-01

    Full Text Available Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favour microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signalling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.

  15. Botulinum A toxin utilizations in obstetric palsy

    Directory of Open Access Journals (Sweden)

    Atakan Aydin

    2012-12-01

    Conclusion: We conclude that with the help of botulinum A toxin and physyotherapy, obstetrical palsy patient with cocontractions can significantly improve movements and may have less surgery. [Hand Microsurg 2012; 1(3.000: 89-94

  16. Toxin Detection by Surface Plasmon Resonance

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available Significant efforts have been invested in the past years for the development of analytical methods for fast toxin detection in food and water. Immunochemical methods like ELISA, spectroscopy and chromatography are the most used in toxin detection. Different methods have been linked, e.g. liquid chromatography and mass spectrometry (LC-MS, in order to detect as low concentrations as possible. Surface plasmon resonance (SPR is one of the new biophysical methods which enables rapid toxin detection. Moreover, this method was already included in portable sensors for on-site determinations. In this paper we describe some of the most common methods for toxin detection, with an emphasis on SPR.

  17. NNDSS - Table II. Shiga toxin to Shigellosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Shiga toxin to Shigellosis - 2016. In this Table, provisional* cases of selected†notifiable diseases (≥1,000 cases reported during the...

  18. NNDSS - Table II. Shiga toxin to Shigellosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Shiga toxin to Shigellosis - 2015. In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding...

  19. Comparative analysis of the virulence characteristics of epidemic methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from Chinese children: ST59 MRSA highly expresses core gene-encoded toxin.

    Science.gov (United States)

    Li, Shipeng; Sun, Jing; Zhang, Jianzhong; Li, Xiangmei; Tao, Xiaoxia; Wang, Lijuan; Sun, Mingjiao; Liu, Yingchao; Li, Juan; Qiao, Yanhong; Yu, Sangjie; Yao, Kaihu; Yang, Yonghong; Shen, Xuzhuang

    2014-02-01

    This study aims to investigate the prevalence of a novel cell wall-anchored protein gene, sasX, and to obtain information on the genetic basis for the pathogenic potential of the MRSA strains isolated from Chinese children. The molecular and virulence characteristics of the clinical strains were analyzed. Twenty-two sequence types (STs) were obtained, with six epidemic clones ST59, ST239, ST1, ST910, ST88, and ST338 accounting for 35.8, 22, 6.6, 6.6, 5.3, and 4.1% respectively. The expression levels of hla, psmα, and RNAIII were higher in ST59 than in other STs (p MRSA isolates. ST239-MRSA-SCCmecIII-t037 (61.5%) was the predominant sasX-positive MRSA clone. The expressions of PSMα and RNAIII were higher in sasX-positive ST239 isolates than in sasX-negative ST239 ones (p MRSA was higher than that by sasX-negative ST239 MRSA (p = 0.008). This study indicated that ST59 was the predominant clone in the MRSA isolates obtained from Chinese children and might have stronger pathogenic potential. The prevalence of the sasX gene in the MRSA isolates from children was relatively low. Furthermore, the sasX gene might be related to the expressions of PSMα and RNAIII and infection invasiveness. © 2013 APMIS Published by John Wiley & Sons Ltd.

  20. Ultrasound-guided botulinum toxin injections

    OpenAIRE

    S. E. Khatkova; A. A. Balbert

    2016-01-01

    One of the key conditions for achieving the desirable result during botulinum toxin therapy for muscular dystonia, spasticity, and other diseases accompanied by spasm, pain, and autonomic dysfunction (dystonias, spasticity, etc.) is the proper administration of the agent into the muscles directly involved in the pathological process. The exact entry of botulinum toxin into the target muscles is essential for successful and safe treatment because its injection into a normal muscle may cause si...

  1. Botulinum toxin treatment of hemifacial spasm.

    OpenAIRE

    Elston, J S

    1986-01-01

    Six patients with hemifacial spasm were treated with injections of botulinum toxin A into the orbicularis oculi; the abnormal movements around the eye were relieved for an average of 15 weeks. There were no systemic or significant local side effects, and in view of the risks involved in neurosurgical treatment, a trial of botulinum toxin injections is recommended in the first instance in this condition.

  2. Botulinum toxin treatment of hemifacial spasm.

    Science.gov (United States)

    Elston, J S

    1986-01-01

    Six patients with hemifacial spasm were treated with injections of botulinum toxin A into the orbicularis oculi; the abnormal movements around the eye were relieved for an average of 15 weeks. There were no systemic or significant local side effects, and in view of the risks involved in neurosurgical treatment, a trial of botulinum toxin injections is recommended in the first instance in this condition. PMID:3746313

  3. Biodegradation of the Polyketide Toxin Cercosporin

    OpenAIRE

    Mitchell, Thomas K.; Chilton, William Scott; Daub, Margaret E.

    2002-01-01

    Cercosporin is a non-host-specific polyketide toxin produced by many species of plant pathogens belonging to the genus Cercospora. This red-pigmented, light-activated toxin is an important pathogenicity determinant for Cercospora species. In this study, we screened 244 bacterial isolates representing 12 different genera for the ability to degrade cercosporin. Cercosporin degradation was determined by screening for the presence of cleared zones surrounding colonies on cercosporin-containing cu...

  4. [Amanita phalloides toxins in dried mushrooms].

    Science.gov (United States)

    Klán, J; Baudisová, D

    1993-08-05

    The content of toxins from Amanita phalloides in dried carpophores is decreasing in the dependence on time. The content of alpha-amanitin found after 20 years was about one half. A mere trace of alpha-amanitin which is the most stable of all toxins was detected in a carpophore 50 years old. Degradation of amatoxins and phallotoxins by light (mainly the UV part) and high temperatures was observed.

  5. Toxicological Perspective on Climate Change: Aquatic Toxins.

    Science.gov (United States)

    Botana, Luis M

    2016-04-18

    In recent years, our group and several others have been describing the presence of new, not previously reported, toxins of high toxicity in vectors that may reach the human food chain. These include tetrodotoxin in gastropods in the South of Europe, ciguatoxin in fish in the South of Spain, palytoxin in mussels in the Mediterranean Sea, pinnatoxin all over Europe, and okadaic acid in the south of the U.S. There seem to be new marine toxins appearing in areas that are heavy producers of seafood, and this is a cause of concern as most of these new toxins are not included in current legislation and monitoring programs. Along with the new toxins, new chemical analogues are being reported. The same phenomenom is being recorded in freshwater toxins, such as the wide appearance of cylindrospermopsin and the large worldwide increase of microcystin. The problem that this phenomenon, which may be linked to climate warming, poses for toxicologists is very important not only because there is a lack of chronic studies and an incomplete comprehension of the mechanism driving the production of these toxins but also because the lack of a legal framework for them allows many of these toxins to reach the market. In some cases, it is very difficult to control these toxins because there are not enough standards available, they are not always certified, and there is an insufficient understanding of the toxic equivalency factors of the different analogues in each group. All of these factors have been revealed and grouped through the massive increase in the use of LC-MS as a monitoring tool, legally demanded, creating more toxicological problems.

  6. Updates on tetanus toxin: a fundamental approach

    Directory of Open Access Journals (Sweden)

    Md. Ahaduzzaman

    2015-03-01

    Full Text Available Clostridium tetani is an anaerobic bacterium that produces second most poisonous protein toxins than any other bacteria. Tetanus in animals is sporadic in nature but difficult to combat even by using antibiotics and antiserum. It is crucial to understand the fundamental mechanisms and signals that control toxin production for advance research and medicinal uses. This review was intended for better understanding the basic patho-physiology of tetanus and neurotoxins (TeNT among the audience of related field.

  7. Influence of Magnolol on the Secretion of α-Toxin by Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Xu-Ming Deng

    2010-03-01

    Full Text Available In this study we investigated the antimicrobial activity of magnolol on Staphylococcus aureus. The minimal inhibitory concentrations of magnolol against 31 S. aureus strains ranged from 4–32 μg/mL. In addition, hemolysin assays, Western blotting, and real-time RT-PCR were performed to investigate the effect of magnolol on α-toxin secretion by both methicillin-sensitive S. aureus (MSSA and methicillin-resistant S. aureus (MRSA. The results indicated that sub-inhibitory concentrations of magnolol dose-dependently inhibited the transcription of hla (the gene encoding α-toxin in S. aureus, resulting in a reduction of α-toxin secretion and, thus, hemolytic activities.

  8. Authentic display of a cholera toxin epitope by chimeric type 1 fimbriae

    DEFF Research Database (Denmark)

    Stentebjerg-Olesen, Bodil; Pallesen, Lars; Jensen, Lars Bogø

    1997-01-01

    The potential of the major structural protein of type 1 fimbriae as a display system for heterologous sequences was tested. As a reporter-epitope, a heterologous sequence mimicking a neutralizing epitope of the cholera toxin B chain was inserted, in one or two copies, into four different positions...... in the fimA gene. This was carried out by introduction of new restriction sites by PCR-mediated site-directed mutagenesis of fimA in positions predicted to correspond to optimally surface-located regions of the subunit protein. Subsequently, the synthetic cholera-toxin-encoding DNA segment was inserted....... Several of the chosen positions seemed amenable even for large foreign inserts; the chimeric proteins were exposed on the bacterial surface and the cholera toxin epitope was authentically displayed, i.e. it was recognized on bacteria by specific antiserum. Display of chimeric fimbriae was tested...

  9. Sea Anemone Toxins Affecting Potassium Channels

    Science.gov (United States)

    Diochot, Sylvie; Lazdunski, Michel

    The great diversity of K+ channels and their wide distribution in many tissues are associated with important functions in cardiac and neuronal excitability that are now better understood thanks to the discovery of animal toxins. During the past few decades, sea anemones have provided a variety of toxins acting on voltage-sensitive sodium and, more recently, potassium channels. Currently there are three major structural groups of sea anemone K+ channel (SAK) toxins that have been characterized. Radioligand binding and electrophysiological experiments revealed that each group contains peptides displaying selective activities for different subfamilies of K+ channels. Short (35-37 amino acids) peptides in the group I display pore blocking effects on Kv1 channels. Molecular interactions of SAK-I toxins, important for activity and binding on Kv1 channels, implicate a spot of three conserved amino acid residues (Ser, Lys, Tyr) surrounded by other less conserved residues. Long (58-59 amino acids) SAK-II peptides display both enzymatic and K+ channel inhibitory activities. Medium size (42-43 amino acid) SAK-III peptides are gating modifiers which interact either with cardiac HERG or Kv3 channels by altering their voltage-dependent properties. SAK-III toxins bind to the S3C region in the outer vestibule of Kv channels. Sea anemones have proven to be a rich source of pharmacological tools, and some of the SAK toxins are now useful drugs for the diagnosis and treatment of autoimmune diseases.

  10. Botulinum toxin for the treatment of strabismus.

    Science.gov (United States)

    Rowe, Fiona J; Noonan, Carmel P

    2017-03-02

    The use of botulinum toxin as an investigative and treatment modality for strabismus is well reported in the medical literature. However, it is unclear how effective it is in comparison to other treatment options for strabismus. The primary objective was to examine the efficacy of botulinum toxin therapy in the treatment of strabismus compared with alternative conservative or surgical treatment options. This review sought to ascertain those types of strabismus that particularly benefit from the use of botulinum toxin as a treatment option (such as small angle strabismus or strabismus with binocular potential, i.e. the potential to use both eyes together as a pair). The secondary objectives were to investigate the dose effect and complication rates associated with botulinum toxin. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2016), Embase (January 1980 to July 2016), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to July 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 11 July 2016. We handsearched the British and Irish Orthoptic Journal, Australian Orthoptic Journal, proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA) and International Orthoptic Association (IOA) (www.liv.ac.uk/orthoptics/research/search.htm) and American Academy of Paediatric Ophthalmology and Strabismus meetings (AAPOS). We contacted researchers who are active in this field for information about further

  11. Identification of the main toxins isolated from Fusarium oxysporum f. sp. pisi race 2 and their relation with isolates' pathogenicity.

    Science.gov (United States)

    Bani, Moustafa; Rispail, Nicolas; Evidente, Antonio; Rubiales, Diego; Cimmino, Alessio

    2014-03-26

    Fusarium oxysporum f. sp. pisi (Fop) is a pathogen of field pea inducing severe vascular wilt worldwide. Plant resistance to races 1, 5, and 6, producing wilt symptoms, is conferred by a single dominant gene, while resistance to race 2, which gives near-wilt symptoms, have been recently showed to be quantitative. Among the virulence factors reported to play a role in the infection process, toxin production is one of the best studied. Thus, five race 2 isolates have been investigated for toxin production in vitro and their relation to isolates' pathogenicity. All the isolates produced different amounts of fusaric and 9,10-dehydrofusaric acids. The content of the two toxins has been quantitated and correlated with the pathogenicity and aggressiveness of isolates on field pea. Results suggested that toxin production is an important determinant of Fop race 2 pathogenicity.

  12. Crystallization and preliminary crystallographic studies of the Pasteurella multocida toxin catalytic domain

    Energy Technology Data Exchange (ETDEWEB)

    Miyazawa, Masayuki [Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan); Kitadokoro, Kengo [Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Kamitani, Shigeki; Shime, Hiroaki; Horiguchi, Yasuhiko, E-mail: horiguti@biken.osaka-u.ac.jp [Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

    2006-09-01

    The C-terminal catalytic domain of P. multocida toxin, which is the virulence factor of the organism in P. multocida, has been expressed, purified and subsequently crystallized using the sitting-drop vapour-diffusion technique. The C-terminal catalytic domain of Pasteurella multocida toxin, which is the virulence factor of the organism in P. multocida, has been expressed, purified and subsequently crystallized using the sitting-drop vapour-diffusion technique. Native diffraction data to 1.9 Å resolution were obtained at the BL44XU beamline of SPring-8 from a flash-frozen crystal at 100 K. The crystals belong to space group C2, with unit-cell parameters a = 111.0, b = 150.4, c = 77.1 Å, β = 105.5°, and are likely to contain one C-PMT (726 residues) per asymmetric unit.

  13. Evidence against a human cell-specific role for LRP6 in anthrax toxin entry.

    Directory of Open Access Journals (Sweden)

    Patricia L Ryan

    2008-03-01

    Full Text Available The role of the cellular protein LRP6 in anthrax toxin entry is controversial. Previous studies showed that LRP6 was important for efficient intoxication of human M2182 prostate carcinoma cells but other studies performed with cells from gene-knockout mice demonstrated no role for either LRP6 or the related LRP5 protein in anthrax toxin entry. One possible explanation for this discrepancy is that LRP6 may be important for anthrax toxin entry into human, but not mouse, cells. To test this idea we have investigated the effect of knocking down LRP6 or LRP5 expression with siRNAs in human HeLa cells. We show here that efficient knockdown of either LRP6, LRP5, or both proteins has no influence on the kinetics of anthrax lethal toxin entry or MEK1 substrate cleavage in these cells. These data argue against a human-specific role for LRP6 in anthrax toxin entry and suggest instead that involvement of this protein may be restricted to certain cell types independently of their species of origin.

  14. Identification of a Bacillus thuringiensis Cry8Da toxin-binding glucosidase from the adult Japanese beetle, Popillia japonica.

    Science.gov (United States)

    Yamaguchi, Takuya; Bando, Hisanori; Asano, Shin-ichiro

    2013-06-01

    Cry8Da from Bacillus thuringiensis galleriae SDS-502 has insecticidal activity against both the larvae and adult Japanese beetle (Popillia japonica Newman). The receptor determines the specificity of the insecticidal activity of Cry proteins and hence, in order to reveal the mode of action of Cry toxin, receptor identification is a necessary step. However, a receptor for Cry8-type toxin has not been identified in the Scarabaeidae family of insects. Therefore, we aimed to identify the receptor of Cry8Da toxin in adult P. japonica BBMV. A ligand blot showed the Cry8Da toxin only bound to a 150kDa protein in the BBMV of adult P. japonica. In order to identify the Cry8Da toxin binding protein, it was purified by column chromatography and three internal amino acid sequences were determined. Two of the three internal amino acid sequences shared homology with Coleopteran β-glucosidases. In addition, the fraction containing the Cry8Da toxin binding protein had β-glucosidase activity but no aminopeptidase N and alkaline phosphatase activity, both of which are commonly reported as receptors for Cry toxins in Lepidopteran and Dipteran insects. The β-glucosidase homologous genes could be amplified by PCR using degenerate oligonucleotide primers designed from a conserved sequence of Coleopteran β-glucosidases and an internal amino acid sequence of the Cry8Da toxin binding protein. Taken together, the β-glucosidase in adult P. japonica BBMV is the receptor for B. thuringiensis Cry8Da toxin. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. RNA editing in bacteria recodes multiple proteins and regulates an evolutionarily conserved toxin-antitoxin system.

    Science.gov (United States)

    Bar-Yaacov, Dan; Mordret, Ernest; Towers, Ruth; Biniashvili, Tammy; Soyris, Clara; Schwartz, Schraga; Dahan, Orna; Pilpel, Yitzhak

    2017-10-01

    Adenosine (A) to inosine (I) RNA editing is widespread in eukaryotes. In prokaryotes, however, A-to-I RNA editing was only reported to occur in tRNAs but not in protein-coding genes. By comparing DNA and RNA sequences of Escherichia coli, we show for the first time that A-to-I editing occurs also in prokaryotic mRNAs and has the potential to affect the translated proteins and cell physiology. We found 15 novel A-to-I editing events, of which 12 occurred within known protein-coding genes where they always recode a tyrosine (TAC) into a cysteine (TGC) codon. Furthermore, we identified the tRNA-specific adenosine deaminase (tadA) as the editing enzyme of all these editing sites, thus making it the first identified RNA editing enzyme that modifies both tRNAs and mRNAs. Interestingly, several of the editing targets are self-killing toxins that belong to evolutionarily conserved toxin-antitoxin pairs. We focused on hokB, a toxin that confers antibiotic tolerance by growth inhibition, as it demonstrated the highest level of such mRNA editing. We identified a correlated mutation pattern between the edited and a DNA hard-coded Cys residue positions in the toxin and demonstrated that RNA editing occurs in hokB in two additional bacterial species. Thus, not only the toxin is evolutionarily conserved but also the editing itself within the toxin is. Finally, we found that RNA editing in hokB increases as a function of cell density and enhances its toxicity. Our work thus demonstrates the occurrence, regulation, and functional consequences of RNA editing in bacteria. © 2017 Bar-Yaacov et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity.

    Science.gov (United States)

    Méndez-Olvera, Estela T; Bustos-Martínez, Jaime A; López-Vidal, Yolanda; Verdugo-Rodríguez, Antonio; Martínez-Gómez, Daniel

    2016-10-01

    Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). The results obtained showed that the eight strains of C. jejuni, including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA, cdtB and cdtC genes.

  17. The role of Campylobacter jejuni cytolethal distending toxin in gastroenteritis: toxin detection, antibody production, and clinical outcome.

    Science.gov (United States)

    Mortensen, Ninell P; Schiellerup, Peter; Boisen, Nadia; Klein, Bjarke M; Locht, Henning; Abuoun, Manal; Newell, Diane; Krogfelt, Karen A

    2011-09-01

    The role of Campylobacter jejuni cytolethal distending toxin (CDT) on clinical outcome after gastroenteritis was investigated. Clinical data, blood serum samples, and Campylobacter spp. isolated, from each of 30 patients were collected over a period of 6 months. The CDT encoding genes, cdtABC, characterized by PCR, revealed that all but one of the C. jejuni strains had the wild-type sequence. Sequencing of cdtABC from this strain showed two major deletions. From all of the strains, CDT titers were determined, and toxin neutralizing antibodies were documented using an in vitro assay. Three of the thirty clinical isolates, including the one with the mutant cdtABC coding genes, did not have a detectable CDT activity. Analyzing the relationship between CDT titer, serum neutralization of CDT, and the clinical outcome showed that campylobacteriosis caused by CDT-negative strains was clinically indistinguishable from that of patients infected with an isolate that produced high levels of CDT. These results suggest that CDT does not solely determine severity of infection and clinical outcome. © 2011 The Authors. APMIS © 2011 APMIS.

  18. The role of Campylobacter jejuni cytolethal distending toxin in gastroenteritis: toxin detection, antibody production, and clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Boisen, Nadia [University of Virginia School of Medicine

    2011-01-01

    The role of Campylobacter jejuni cytolethal distending toxin (CDT) on clinical outcome after gastroenteritis was investigated. Clinical data, blood serum samples, and Campylobacter spp. isolated, from each of 30 patients were collected over a period of 6 months. The CDT encoding genes, cdtABC, characterized by PCR, revealed that all but one of the C. jejuni strains had the wild-type sequence. Sequencing of cdtABC from this strain showed two major deletions. From all of the strains, CDT titers were determined, and toxin neutralizing antibodies were documented using an in vitro assay. Three of the thirty clinical isolates, including the one with the mutant cdtABC coding genes, did not have a detectable CDT activity. Analyzing the relationship between CDT titer, serum neutralization of CDT, and the clinical outcome showed that campylobacteriosis caused by CDT-negative strains was clinically indistinguishable from that of patients infected with an isolate that produced high levels of CDT. These results suggest that CDT does not solely determine severity of infection and clinical outcome.

  19. [Botulinum toxin therapy for spasticity].

    Science.gov (United States)

    Masakado, Yoshihisa

    2014-09-01

    Botulinum toxin (BTX) administered as an adjunct to other interventions for spasticity can act as a useful and effective therapeutic tool for treating patients disabled by spasticity. Presence of other non-reflex motor disorders (muscle stiffness, shortness, and contracture) can complicate the clinical course and disturb rehabilitative process of patients with spasticity. Treatment of spasticity using BTX can improve paralysis by correcting muscular imbalance that follows these diseases. In patients with chronic severe spasticity, we also have to address unique and difficult-to-treat clinical conditions such as abnormal posture and movement disorders. The effectiveness of BTX in treating some of these conditions is discussed. Because patients with neurological disabilities can show complex dysfunctions, specific functional limitations, goals, and expected outcomes of treatment should be evaluated and discussed with the patient, family members, and caregivers, prior to initiating BTX therapy. BTX therapy might improve not only care, passive function, but also motor functions in these patients by supplementing intensive rehabilitation with repetitive transcranial magnetic stimulation, transcranial direct-current stimulation, peripheral electrical stimulation, muscle stretching, and other rehabilitation strategies.

  20. Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces.

    Science.gov (United States)

    Robledo, M; Rivera, L; Jiménez-Zurdo, Jose I; Rivas, R; Dazzo, F; Velázquez, E; Martínez-Molina, E; Hirsch, Ann M; Mateos, Pedro F

    2012-09-12

    The synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encoding an endoglucanase (CelC2) that is required for canonical symbiotic root hair infection by Rhizobium leguminosarum bv. trifolii. ANU843 celC mutants lacking (ANU843ΔC2) or overproducing cellulase (ANU843C2+) produced greatly increased or reduced amounts of external cellulose micro fibrils, respectively. Calcofluor-stained cellulose micro fibrils were considerably longer when formed by ANU843ΔC2 bacteria rather than by the wild-type strain, in correlation with a significant increase in their flocculation in batch culture. In contrast, neither calcofluor-stained extracellular micro fibrils nor flocculation was detectable in ANU843C2+ cells. To clarify the role of cellulose synthesis in Rhizobium cell aggregation and attachment, we analyzed the ability of these mutants to produce biofilms on different surfaces. Alteration of wild-type CelC2 levels resulted in a reduced ability of bacteria to form biofilms both in abiotic surfaces and in planta. Our results support a key role of the CelC2 cellulase in cellulose biosynthesis by modulating the length of the cellulose fibrils that mediate firm adhesion among Rhizobium bacteria leading to biofilm formation. Rhizobium cellulose is an essential component of the biofilm polysaccharidic matrix architecture and either an excess or a defect of this "building material" seem to collapse the biofilm structure. These results position cellulose hydrolytic enzymes as excellent anti-biofilm candidates.

  1. The role of C2-C7 and O-C2 angle in the development of dysphagia after cervical spine surgery.

    Science.gov (United States)

    Tian, Wei; Yu, Jie

    2013-06-01

    Dysphagia is a known complication of cervical surgery and may be prolonged or occasionally serious. A previous study showed that dysphagia after occipitocervical fusion was caused by oropharyngeal stenosis resulting from O-C2 (upper cervical lordosis) fixation in a flexed position. However, there have been few reports analyzing the association between the C2-C7 angle (middle-lower cervical lordosis) and postoperative dysphagia. The aim of this study was to analyze the relationship between cervical lordosis and the development of dysphagia after anterior and posterior cervical spine surgery (AC and PC). Three hundred fifty-four patients were reviewed in this retrospective clinical study, including 172 patients who underwent the AC procedure and 182 patients who had the PC procedure between June 2007 and May 2010. The presence and duration of postoperative dysphagia were recorded via face-to-face questioning or telephone interview performed at least 1 year after the procedure. Plain cervical radiographs before and after surgery were collected. The O-C2 angle and the C2-C7 angle were measured. Changes in the O-C2 angle and the C2-C7 angle were defined as dO-C2 angle = postoperative O-C2 angle - preoperative O-C2 angle and dC2-C7 angle = postoperative C2-C7 angle - preoperative C2-C7 angle. The association between postoperative dysphagia with dO-C2 angle and dC2-C7 angle was studied. Results showed that 12.8 % of AC and 9.4 % of PC patients reported dysphagia after cervical surgery. The dC2-C7 angle has considerable impact on postoperative dysphagia. When the dC2-C7 angle is greater than 5°, the chance of developing postoperative dysphagia is significantly greater. The dO-C2 angle, age, gender, BMI, operative time, blood loss, procedure type, revision surgery, most cephalic operative level, and number of operative levels did not significantly influence the incidence of postoperative dysphagia. No relationship was found between the dC2-C7 angle and the degree of

  2. Analysis of the effect of aluminum in drinking water and transferrin C2 allele on Alzheimer's disease.

    Science.gov (United States)

    Rondeau, V; Iron, A; Letenneur, L; Commenges, D; Duchêne, F; Arveiler, B; Dartigues, J-F

    2006-09-01

    Although highly controversial, the hypothesis of a link between aluminum (Al) in drinking water and Alzheimer's disease (AD) has been supported by several epidemiological studies. Transferrin (Tf) is a major transport protein for both iron and Al. Moreover, it has been demonstrated that defective binding of iron and Al to the Tf variant C2 could be present in AD. Individuals carrying the Tf C2 allele might therefore be at greater risk of developing AD. We investigated whether the Tf C2 allele might be responsible for susceptibility to AD in a sample of 292 subjects (with 55 AD) aged > or = 75 years from south-west France, some exposed to high levels of Al in tap water (n = 1