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Sample records for c2 toxin gene

  1. EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R.; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Tehran, Domenico Azarnia; Montecucco, Cesare; Barth, Holger

    2016-01-01

    The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins. PMID:27043629

  2. Chloroquine Analog Interaction with C2- and Iota-Toxin in Vitro and in Living Cells.

    Science.gov (United States)

    Kronhardt, Angelika; Beitzinger, Christoph; Barth, Holger; Benz, Roland

    2016-01-01

    C2-toxin from Clostridium botulinum and Iota-toxin from Clostridium perfringens belong both to the binary A-B-type of toxins consisting of two separately secreted components, an enzymatic subunit A and a binding component B that facilitates the entry of the corresponding enzymatic subunit into the target cells. The enzymatic subunits are in both cases actin ADP-ribosyltransferases that modify R177 of globular actin finally leading to cell death. Following their binding to host cells' receptors and internalization, the two binding components form heptameric channels in endosomal membranes which mediate the translocation of the enzymatic components Iota a and C2I from endosomes into the cytosol of the target cells. The binding components form ion-permeable channels in artificial and biological membranes. Chloroquine and related 4-aminoquinolines were able to block channel formation in vitro and intoxication of living cells. In this study, we extended our previous work to the use of different chloroquine analogs and demonstrate that positively charged aminoquinolinium salts are able to block channels formed in lipid bilayer membranes by the binding components of C2- and Iota-toxin. Similarly, these molecules protect cultured mammalian cells from intoxication with C2- and Iota-toxin. The aminoquinolinium salts did presumably not interfere with actin ADP-ribosylation or receptor binding but blocked the pores formed by C2IIa and Iota b in living cells and in vitro. The blocking efficiency of pores formed by Iota b and C2IIa by the chloroquine analogs showed interesting differences indicating structural variations between the types of protein-conducting nanochannels formed by Iota b and C2IIa. PMID:27517960

  3. Chloroquine Analog Interaction with C2- and Iota-Toxin in Vitro and in Living Cells

    Science.gov (United States)

    Kronhardt, Angelika; Beitzinger, Christoph; Barth, Holger; Benz, Roland

    2016-01-01

    C2-toxin from Clostridium botulinum and Iota-toxin from Clostridium perfringens belong both to the binary A-B-type of toxins consisting of two separately secreted components, an enzymatic subunit A and a binding component B that facilitates the entry of the corresponding enzymatic subunit into the target cells. The enzymatic subunits are in both cases actin ADP-ribosyltransferases that modify R177 of globular actin finally leading to cell death. Following their binding to host cells’ receptors and internalization, the two binding components form heptameric channels in endosomal membranes which mediate the translocation of the enzymatic components Iota a and C2I from endosomes into the cytosol of the target cells. The binding components form ion-permeable channels in artificial and biological membranes. Chloroquine and related 4-aminoquinolines were able to block channel formation in vitro and intoxication of living cells. In this study, we extended our previous work to the use of different chloroquine analogs and demonstrate that positively charged aminoquinolinium salts are able to block channels formed in lipid bilayer membranes by the binding components of C2- and Iota-toxin. Similarly, these molecules protect cultured mammalian cells from intoxication with C2- and Iota-toxin. The aminoquinolinium salts did presumably not interfere with actin ADP-ribosylation or receptor binding but blocked the pores formed by C2IIa and Iota b in living cells and in vitro. The blocking efficiency of pores formed by Iota b and C2IIa by the chloroquine analogs showed interesting differences indicating structural variations between the types of protein-conducting nanochannels formed by Iota b and C2IIa. PMID:27517960

  4. ADP-ribosylation of actins in fibroblasts and myofibroblasts by botulinum C2 toxin: Influence on microfilament morphology and migratory behavior

    DEFF Research Database (Denmark)

    Rønnov-Jessen, Lone; Petersen, Ole William

    1996-01-01

    botulinum C2 toxin. The substrate for C2 toxin is globular actin, which upon ribosylation cannot incorporate into microfilaments. The pattern of actin ADP-ribosylation in (myo)fibroblasts in the presence of [32P]NAD was analyzed by isoelectric focusing, fluorography and immunoblotting. The influence of C2...... toxin on microfilaments in intact cells was further assessed by immunofluorescence, and motility was measured in a mass migration assay and by computerized video time-lapse microscopy. We show here that C2 toxin specifically ribosylates - and -actin in both fibroblasts and myofibroblasts. Whereas...

  5. Gene therapy for carcinoma of the breast: Genetic toxins

    International Nuclear Information System (INIS)

    Gene therapy was initially envisaged as a potential treatment for genetically inherited, monogenic disorders. The applications of gene therapy have now become wider, however, and include cardiovascular diseases, vaccination and cancers in which conventional therapies have failed. With regard to oncology, various gene therapy approaches have been developed. Among them, the use of genetic toxins to kill cancer cells selectively is emerging. Two different types of genetic toxins have been developed so far: the metabolic toxins and the dominant-negative class of toxins. This review describes these two different approaches, and discusses their potential applications in cancer gene therapy

  6. Regulation of toxin gene expression in Clostridium perfringens.

    Science.gov (United States)

    Ohtani, Kaori; Shimizu, Tohru

    2015-05-01

    The Gram-positive, anaerobic, spore-forming, rod-shaped Clostridium perfringens is widely distributed in nature, especially in soil and the gastrointestinal tract of humans and animals. C. perfringens causes clostridial myonecrosis (or gas gangrene), enteritis and enterotoxemia in humans and livestock by producing numerous extracellular toxins and enzymes. The toxin gene expression is regulated by a two-component regulatory system and regulatory RNA VirR/VirS-VR-RNA cascade. The VirR/VirS system was originally found in a type A strain, but a recent report showed that it is also important for the toxin gene regulation in other types of strains. Two types of cell-cell signaling, i.e., agr-system and AI-2 signaling, are also important for the regulation of toxin genes. Several regulatory systems independent from the VirR/VirS system, including virX, the orphan histidine kinase ReeS and orphan response regulator RevR, are also involved in the regulation of toxin genes. In addition, the expression of toxin genes is upregulated after contact with Caco-2 cells. C. perfringens has a complex regulatory network for toxin gene expression and thus the coordination of toxin gene expression is important for the process of infection. PMID:25303832

  7. Toxin gene determination and evolution in scorpaenoid fish.

    Science.gov (United States)

    Chuang, Po-Shun; Shiao, Jen-Chieh

    2014-09-01

    In this study, we determine the toxin genes from both cDNA and genomic DNA of four scorpaenoid fish and reconstruct their evolutionary relationship. The deduced protein sequences of the two toxin subunits in Sebastapistes strongia, Scorpaenopsis oxycephala, and Sebastiscus marmoratus are about 700 amino acid, similar to the sizes of the stonefish (Synanceia horrida, and Synanceia verrucosa) and lionfish (Pterois antennata and Pterois volitans) toxins previously published. The intron positions are highly conserved among these species, which indicate the applicability of gene finding by using genomic DNA template. The phylogenetic analysis shows that the two toxin subunits were duplicated prior to the speciation of Scorpaenoidei. The precedence of the gene duplication over speciation indicates that the toxin genes may be common to the whole family of Scorpaeniform. Furthermore, one additional toxin gene has been determined in the genomic DNA of Dendrochirus zebra. The phylogenetic analysis suggests that an additional gene duplication occurred before the speciation of the lionfish (Pteroinae) and a pseudogene may be generally present in the lineage of lionfish. PMID:24950049

  8. Toxins

    Science.gov (United States)

    Toxins are substances created by plants and animals that are poisonous to humans. Toxins also include some medicines that are helpful in small doses, but poisonous in large amounts. Most toxins that ...

  9. Bacteriophage-mediated toxin gene regulation in Clostridium difficile.

    Science.gov (United States)

    Govind, Revathi; Vediyappan, Govindsamy; Rolfe, Rial D; Dupuy, Bruno; Fralick, Joe A

    2009-12-01

    Clostridium difficile has been identified as the most important single identifiable cause of nosocomial antibiotic-associated diarrhea and colitis. Virulent strains of C. difficile produce two large protein toxins, toxin A and toxin B, which are involved in pathogenesis. In this study, we examined the effect of lysogeny by PhiCD119 on C. difficile toxin production. Transcriptional analysis demonstrated a decrease in the expression of pathogenicity locus (PaLoc) genes tcdA, tcdB, tcdR, tcdE, and tcdC in PhiCD119 lysogens. During this study we found that repR, a putative repressor gene of PhiCD119, was expressed in C. difficile lysogens and that its product, RepR, could downregulate tcdA::gusA and tcdR::gusA reporter fusions in Escherichia coli. We cloned and purified a recombinant RepR containing a C-terminal six-His tag and documented its binding to the upstream regions of tcdR in C. difficile PaLoc and in repR upstream region in PhiCD119 by gel shift assays. DNA footprinting experiments revealed similarities between the RepR binding sites in tcdR and repR upstream regions. These findings suggest that presence of a CD119-like temperate phage can influence toxin gene regulation in this nosocomially important pathogen. PMID:19776116

  10. A cell-permeable fusion protein based on Clostridium botulinum C2 toxin for delivery of p53 tumorsuppressor into cancer cells.

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    Jörg Fahrer

    Full Text Available Genetically engineered bacterial protein toxins are attractive systems for delivery of exogenous proteins into the cytosol of mammalian cells. The binary C2 toxin from C. botulinum has emerged as powerful delivery vehicle, which rests on its binding/translocation component C2IIa and the genetically modified adaptor domain C2IN that act in concert to trigger cell uptake. The p53 tumor suppressor protein has a crucial function in suppressing carcinogenesis and is frequently inactivated by diverse mechanisms in human tumor cells. Therefore, we constructed a C2IN-p53 fusion protein, which is internalized into cancer cells by C2IIa. To this end, the C2IN-p53 fusion construct was overexpressed in E. coli with good solubility, purified by heparin affinity chromatography and protein identity was confirmed by immunoblotting. We demonstrated that the fusion protein is capable of binding to the p53 consensus-DNA with high affinity in a p53-specific manner in vitro. Next, the internalization of C2IN-p53 was monitored in HeLa cells by cell fractionation and immunoblot analysis, which revealed a C2IIa-mediated translocation of the fusion protein into the cytosol. The uptake was also shown in A549 and Saos-2 cells with similar efficiency. These findings were further corroborated by confocal immunofluorescence analyses of C2IN-p53/C2IIa-treated HeLa and A549 cells, displaying predominantly cytoplasmic localization of the fusion construct.

  11. Reporter Gene Assay for Detection of Shellfish Toxins

    Institute of Scientific and Technical Information of China (English)

    WEI-DONG YANG; MIN-YI WU; JIE-SHENG LIU; XI-CHUN PENG; HONG-YE LI

    2009-01-01

    Objective To explore the potential reporter gene assay for the detection of sodium channel-specific toxins in shellfish as an alternative for screening harmful algal bloom (HAB) toxins, considering the fact that the existing methods including HPLC and bioassay are inappropriate for identifying HAB toxins which poses a serious problem on human health and shellfish industry. Methods A reporter plasmid pEGFP-c-fos containing c-fos promoter and EGFP was constructed and transfected into T24 cells using LipofectAMINE 2000. Positive transfectants were screened by G418 to produce a pEGFP-c-fos-T24 cell line. After addition of increasing neurotoxic shellfish poison (NSP) or GTX2,3, primary components of paralytic shellfish poison (PSP), changes in expression of EGFP in the cell line were observed under a laser scanning confocal microscope and quantified with Image-pro Plus software. Results Dose-dependent changes in the intensity of green fluorescence were observed for NSP in a range from 0 to 10 ng/mL and for GTX 2,3 from 0 to 16 ng/mL. Conclusion pEGFP-c-fos-T24 can be applied in detecting HAB toxins, and cell-based assay can be used as an alternative for screening sodium channel-specific HAB toxins.

  12. Conservation of the genes for HC-toxin biosynthesis in Alternaria jesenskae

    OpenAIRE

    Wight, Wanessa D; Labuda, Roman; Walton, Jonathan D

    2013-01-01

    Background HC-toxin, a cyclic tetrapeptide, is a virulence determinant for the plant pathogenic fungus Cochliobolus carbonum. It was recently discovered that another fungus, Alternaria jesenskae, also produces HC-toxin. Results The major genes (collectively known as AjTOX2) involved in the biosynthesis of HC-toxin were identified from A. jesenskae by genomic sequencing. The encoded orthologous proteins share 75-85% amino acid identity, and the genes for HC-toxin biosynthesis are duplicated in...

  13. Identiifcation of Human Hepatocyte Proliferation Related Gene C2orf69

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    Objective To construct the prokaryotic expression vector pET-32a(+)-C2orf69 and induce the expression of recombinant proteins in vitro. Then the possible effects of recombinant protein on cell proliferation was observed and rabbit-anti-C2orf69 protein polyclonal antibodies was obtained. Methods Gene fragment of C2orf69 was ampliifed by PCR and then prokaryotic expression plasmid pET-32a(+)-C2orf69 was constructed. Recombinant protein C2orf69 expression was identiifed by SDS-PAGE and Western blot. The white-ear rabbits were immunized with purified recombinant protein C2orf69, and the potency and speciifcity of polyclonal antibody were evaluated by enzyme-linked immunosorbent assay (ELISA) and Western blot. Also, different liver cells were incubated with recombinant protein C2orf69 in vitro. Results C2orf69 gene fragment was successfully ampliifed, results of gene sequencing were consistent with the sequence in GenBank. Recombinant protein of C2orf69 was successfully induced and expressed. The polyclonal antibody titer was up to 1︰1 280 000 through enzyme-linked immunosorbent assay. Results of cell proliferation showed that the recombinant protein could inhibit the proliferation of different liver cells. Conclusions The recombinant protein C2orf69 could inhibit the proliferation of different liver cells, and we speculated that it may be a widely roled inhibitor of hepatocyte proliferation. Our experiment showed that the proliferation inhibition of cells may be realized by G1 phase extending and S phase shortening.

  14. Toxins and genes isolated from scorpions of the genus Tityus.

    Science.gov (United States)

    Becerril, B; Marangoni, S; Possani, L D

    1997-06-01

    Scorpion venoms contain a variety of low mol. wt peptides toxic to different organisms. These peptides have been intensively studied because they represent excellent models for investigating structure-function relationships and they are also fine probes for studying ionic channel functions. This review deals with the biological and chemical aspects of toxic peptides that affect Na+ or K+ channels and the cloning of the cDNAs and genes encoding the main alpha and beta neurotoxins present in the venom of the three most dangerous species of Brazilian scorpion, Tityus bahiensis, Tityus stigmurus and Tityus serrulatus, and the Venezuelan scorpion Tityus discrepans. At least 16 different peptides specific for Na+ channels and five affecting K+ channels were isolated and characterized from the venom of these scorpions. The isolation of cDNAs and genes encoding four distinct toxins has permitted the elucidation of their nucleotide sequences as well as their genomic organization. Venoms and isolated toxins from scorpions of the genus Tityus were shown to enhance the secretory activity of the pancreas. Antisera obtained against venom of T. serrulatus show cross-reactivity with other species of the Brazilian scorpions. PMID:9241777

  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. Molecular methods to study transcriptional regulation of Clostridium difficile toxin genes.

    Science.gov (United States)

    Antunes, Ana; Dupuy, Bruno

    2010-01-01

    Toxin A (TcdA) and Toxin B (TcdB) are the major virulence factors that contribute to the pathogenesis of Clostridium difficile-associated diarrhoea (CDAD). These enterotoxins act by glucosylation of members of the Rho protein family of small GTP-binding proteins. This leads to the disorganization of the host cell actin cytoskeleton (cytopathic effect) and apoptosis (cytotoxic effect). Due to their glucosyltransferase activity, they are referred as "clostridial glucosylating toxins". The severe form of CDAD has been recently correlated to the levels of toxin production. This reinforces the idea that regulation of toxin production is an important part of the C. difficile infection. Genes encoding TcdA (tcdA) and TcdB (tcdB) are present in a pathogenicity locus (PaLoc) that also includes three accessory genes: tcdR, tcdE and tcdC. TcdR is an alternative RNA polymerase sigma factor that positively regulates toxin gene transcription as well as its own. TcdE has high homologies with bacteriophage holin proteins. TcdC negatively regulates toxin synthesis by interfering with the RNA polymerase formed with TcdR. Therefore, TcdR and TcdC constitute specific regulators of toxin gene transcription thereby tightly regulating toxin synthesis. In addition a variety of environmental signals, such as the presence of carbon sources or amino acids in the growth medium, and temperature also regulate toxin synthesis. PMID:20597005

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

    Directory of Open Access Journals (Sweden)

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

    Science.gov (United States)

    Xie, Bing; Li, Xiaofeng; Lin, Zhilong; Ruan, Zhiqiang; Wang, Min; Liu, Jie; Tong, Ting; Li, Jia; Huang, Yu; Wen, Bo; Sun, Ying; Shi, Qiong

    2016-01-01

    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. PMID:27089325

  19. First intron of nestin gene regulates its expression during C2C12 myoblast ifferentiation

    Institute of Scientific and Technical Information of China (English)

    Hua Zhong; Zhigang Jin; Yongfeng Chen; Ting Zhang; Wei Bian; Xing Cui; Naihe Jing

    2008-01-01

    Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China Nestin is an intermediate filament protein expressed in neural progenitor cells and in developing skeletal muscle. Nestin has been widely used as a neural progenitor cell marker. It is well established that the specific expression of the nestin gene in neural progenitor cells is conferred by the neural-specific enhancer located in the second intron of the nestin gene. However, the transcriptional mechanism of nestin expression in developing muscle is still unclear. In this study, we identified a muscle cell-specific enhancer in the first intron of mouse nestin gene in mouse myoblast C2C12 cells.We localized the core enhancer activity to the 291-661 region of the first intron, and showed that the two E-boxes in the core enhancer region were important for enhancer activity in differentiating C2C12 cells. We also showed that MyoD protein was involved in the regulation of nestin expression in the myogenic differentiation of C2C12 cells.

  20. Transcriptional activity of acetylcholinesterase gene is regulated by DNA methylation during C2C12 myogenesis.

    Science.gov (United States)

    Lau, Kei M; Gong, Amy G W; Xu, Miranda L; Lam, Candy T W; Zhang, Laura M L; Bi, Cathy W C; Cui, D; Cheng, Anthony W M; Dong, Tina T X; Tsim, Karl W K; Lin, Huangquan

    2016-07-01

    The expression of acetylcholinesterase (AChE), an enzyme hydrolyzes neurotransmitter acetylcholine at vertebrate neuromuscular junction, is regulated during myogenesis, indicating the significance of muscle intrinsic factors in controlling the enzyme expression. DNA methylation is essential for temporal control of myogenic gene expression during myogenesis; however, its role in AChE regulation is not known. The promoter of vertebrate ACHE gene carries highly conserved CG-rich regions, implying its likeliness to be methylated for epigenetic regulation. A DNA methyltransferase inhibitor, 5-azacytidine (5-Aza), was applied onto C2C12 cells throughout the myotube formation. When DNA methylation was inhibited, the promoter activity, transcript expression and enzymatic activity of AChE were markedly increased after day 3 of differentiation, which indicated the putative role of DNA methylation. By bisulfite pyrosequencing, the overall methylation rate was found to peak at day 3 during C2C12 cell differentiation; a SP1 site located at -1826bp upstream of mouse ACHE gene was revealed to be heavily methylated. The involvement of transcriptional factor SP1 in epigenetic regulation of AChE was illustrated here: (i) the SP1-driven transcriptional activity was increased in 5-Aza-treated C2C12 culture; (ii) the binding of SP1 onto the SP1 site of ACHE gene was fully blocked by the DNA methylation; and (iii) the sequence flanking SP1 sites of ACHE gene was precipitated by chromatin immuno-precipitation assay. The findings suggested the role of DNA methylation on AChE transcriptional regulation and provided insight in elucidating the DNA methylation-mediated regulatory mechanism on AChE expression during muscle differentiation. PMID:27021952

  1. 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

    Aims: To study the prevalence of seven virulence and toxin genes, and cytolethal distending toxin (CDT) production of Campylobacter jejuni and C. coli isolates from Danish pigs and cattle. Methods and Results: The presence of the cadF, ceuE, virB11, flaA, cdtA, cdtB, cdtC and the cdt gene cluster...

  2. Activating mutations in the NT5C2 nucleotidase gene drive chemotherapy resistance in relapsed ALL

    Science.gov (United States)

    Tzoneva, Gannie; Garcia, Arianne Perez; Carpenter, Zachary; Khiabanian, Hossein; Tosello, Valeria; Allegretta, Maddalena; Paietta, Elisabeth; Racevskis, Janis; Rowe, Jacob M.; Tallman, Martin S.; Paganin, Maddalena; Basso, Giuseppe; Hof, Jana; Kirschner-Schwabe, Renate; Palomero, Teresa; Rabadan, Raul; Ferrando, Adolfo

    2013-01-01

    Acute lymphoblastic leukemia (ALL) is an aggressive hematological tumor resulting from the malignant transformation of lymphoid progenitors. Despite intensive chemotherapy, 20% of pediatric and over 50% of adult ALL patients fail to achieve a complete remission or relapse after intensified chemotherapy, making disease relapse and resistance to therapy the most significant challenge in the treatment of this disease1,2. Using whole exome sequencing, here we identify mutations in the cytosolic 5'-nucleotidase II gene (NT5C2), which encodes a 5'-nucleotidase enzyme responsible for inactivation of nucleoside analog chemotherapy drugs, in 20/103 (19%) relapse T-ALLs and in 1/35 (3%) relapse B-precursor ALLs analyzed. NT5C2 mutant proteins show increased nucleotidase activity in vitro and conferred resistance to chemotherapy with 6-mercaptopurine and 6-thioguanine when expressed in ALL lymphoblasts. These results support a prominent role for activating mutations in NT5C2 and increased nucleoside analog metabolism in disease progression and chemotherapy resistance in ALL. PMID:23377281

  3. 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

    : 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......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...... more comprehensive picture of the prevalence of the Staph. hyicus exfoliative toxins in Danish pig herds. Significance and Impact of the Study: The multiplex PCR can be used in studies on the prevalence of toxigenic Staph. hyicus elucidating the epidemiology of EE in pigs. The multiplex PCR is...

  4. [Electrochemical detection of toxin gene in Listeria monocytogenes].

    Science.gov (United States)

    Wu, Ling-Wei; Liu, Quan-Jun; Wu, Zhong-Wei; Lu, Zu-Hong

    2010-05-01

    Listeria monocytogenes (LM) is a food-borne pathogen inducing listeriosis, an illness characterized by encephalitis, septicaemia, and meningitis. Listeriolysin O (LLO) is absolutely required for virulence by L. monocytogenes, and is found only in virulent strains of the species. One of the best ways to detect and confirm the pathogen is detection of one of the virulence factors, LLO, produced by the microorganism. This paper focused on the electrical method used to detect the LLO toxin gene in food products and organism without labeling the target DNA. The electrochemical sensor was obtained by immobilizing single-stranded oligonucleotides onto the gold electrode with the mercaptan activated by N-hydroxysulfosuccinimide (NHS) and N-(3-dimethylamion)propyl-N'-ethyl carbodiimidehydrochloride (EDC). The hy-bridization reaction that occurred on the electrode surface was evidenced by Cyclic Voltammetry (CV) analysis using [Co(phen)3](ClO4)3 as an indicator. The covalently immobilized single-stranded DNA could selectively hybridize to its complementary DNA in solution to form double-stranded DNA on the gold surface. A significant increase of the peak cur-rent of Cyclic Voltammetry (CV) upon hybridization of immobilized ssDNA with PCR amplification products in the solu-tion was observed. This peak current change was used to monitor the amount of PCR amplification products. Factors deter-mining the sensitivity of the electrochemical assay, such as DNA target concentration and hybridization conditions, were investigated. The coupling of DNA to the electrochemical sensors has the potential of the quantitative evaluation of gene. PMID:20466642

  5. Genotypes and toxin gene profiles of Staphylococcus aureus clinical isolates from China.

    Directory of Open Access Journals (Sweden)

    Yanping Xie

    Full Text Available A total of 108 S. aureus isolates from 16 major hospitals located in 14 different provinces in China were characterized for the profiles of 18 staphylococcal enterotoxin (SE genes, 3 exfoliatin genes (eta, etb and etd, and the toxic shock syndrome toxin gene (tsst by PCR. The genomic diversity of each isolate was also evaluated by pulsed-field gel electrophoresis (PFGE, multilocus sequence typing (MLST, and accessory gene regulator (agr typing. Of these strains, 90.7% (98/108 harbored toxin genes, in which tsst was the most prevalent toxin gene (48.1%, followed by sea (44.4%, sek (42.6% and seq (40.7%. The see and etb genes were not found in any of the isolates tested. Because of high-frequency transfer of toxin gene-containing mobile genetic elements between S. aureus strains, a total of 47 different toxin gene combinations were detected, including a complete egc cluster in 19 isolates, co-occurrence of sea, sek and seq in 38 strains, and sec and sel together in 11 strains. Genetic typing by PFGE grouped all the strains into 25 clusters based on 80% similarity. MLST revealed 25 sequence types (ST which were assigned into 16 clonal complexes (CCs including 2 new singletons. Among these, 11 new and 6 known STs were first reported in the S. aureus strains from China. Overall, the genotyping results showed high genetic diversity of the strains regardless of their geographical distributions, and no strong correlation between genetic background and toxin genotypes of the strains. For genotyping S. aureus, PFGE appears to be more discriminatory than MLST. However, toxin gene typing combined with PFGE or MLST could increase the discriminatory power of genotyping S. aureus strains.

  6. Phylogenetic relationship of equine Actinobacillus species and distribution of RTX toxin genes among clusters

    OpenAIRE

    Kuhnert, Peter; Berthoud, Hélène; Christensen, Henrik; Bisgaard, Magne; Frey, Joachim

    2003-01-01

    Equine Actinobacillus species were analysed phylogenetically by 16S rRNA gene (rrs) sequencing focusing on the species Actinobacillus equuli, which has recently been subdivided into the non-haemolytic A. equuli subsp. equuli and the haemolytic A. equuli subsp. haemolyticus. In parallel we determined the profile for RTX toxin genes of the sample of strains by PCR testing for the presence of the A. equuli haemolysin gene aqx, and the toxin genes apxI, apxII, apxIII and apxIV, which are known in...

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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...... ranged from 816 to 834 bp. The amino acid sequences of these four toxins were homologous to the earlier described exfoliative toxins SHETB from S. hyicus and ETA, ETB, and ETD from Staphylococcus aureus. The homology between the S. hyicus toxins was at the same level as the homology to the exfoliative...... toxins were recognized by monoclonal antibodies raised against native exfoliative toxins....

  9. 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

    : 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......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...... 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...

  10. Detection of Clostridium perfringens alpha toxin gene in lambs by loop mediated isothermal amplification

    Directory of Open Access Journals (Sweden)

    B. Radhika

    2016-01-01

    Full Text Available Aim: The loop mediated isothermal amplification (LAMP was standardized for rapid detection of Clostridium perfringens. Materials and Methods: A total of 120 fecal samples were collected from enterotoxemia suspected lambs were used for screening of C. perfringens cpa gene by LAMP. The specificity of the LAMP amplified products was tested by digesting with restriction enzyme XmnI for alpha toxin gene. Results: Out of 120 samples screened 112 (93.3% samples were positive by both LAMP and polymerase chain reaction (PCR for detection of cpa gene which indicated the equal sensitivity of both the tests. The enzyme produced single cut in 162 base pair amplified product of alpha toxin gene at 81 base pair resulting in a single band in gel electrophoresis. Conclusion: Both LAMP and PCR for detection of cpa gene indicated the equal sensitivity of both the tests. Standardization of LAMP reaction for amplification of epsilon and beta toxin genes will help to identify the C. perfringens toxin types from the clinical samples. The test could be a suitable alternative to the PCR in detection of toxin types without the help of sophisticated machinery like thermal cycler. Considering its simplicity in operation and high sensitivity, there is the potential use of this technique in clinical diagnosis and surveillance of infectious diseases.

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

    OpenAIRE

    2013-01-01

    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 provin...

  12. 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...... different a-toxin sequence types among the 60 strains. Moreover, a type II intron of 834 non-coding nucleotides was identified in the pic gene of three of the investigated strains. The in vitro alpha-toxin production investigated in 45 of the strains, including the three harbouring the intron, revealed no...... correlation between PFGE type, alpha-toxin sequence type, health status of the host chickens and level of a-toxin production. It is therefore concluded that neither pic gene type nor alpha-toxin production level seems to correlate to origin (healthy or diseased chicken) of the C perfringens strains. (C) 2008...

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Detection of Genes for Superantigen Toxins in Methicillin-Resistant Staphylococcus aureus Clinical Isolates in Karachi

    International Nuclear Information System (INIS)

    Objective: To detect genes for enterotoxins, exfoliative and toxic shock syndrome toxins in Staphylococcus aureus (S. aureus) strains isolated from clinical specimens. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Molecular Genetics, Dr. Ziauddin Hospital, Karachi, from January to December 2010. Methodology: Two hundred and ninety eight S. aureus clinical isolates were obtained from various clinical samples received at Dr. Ziauddin Hospital, Karachi. Out of these, 115 were detected as methicillin resistant (MRSA) by cefoxitin disk diffusion test showing a prevalence rate of 38.6%. Detection of individual toxin genes was performed by Polymerase Chain Reaction (PCR) by using only one primer pair for each tube. Uniplex primers were preferred as multiplex primers are longer in base pairs and have the potential for cross reaction due to non-specific binding and increase in optimization time. Results: The possession of a single gene or more than a single gene in MRSA isolates was found in 61.73% of clinical samples; the highest number was found in pus swab, followed by sputum, blood, urethral swab, and urine. The prevalence of toxin genes was higher in MRSA as compared to methicillin sensitive (MSSA) isolates (19.12%). Conclusion: PCR detects strains possessing toxin genes independent of their expression. The possession of genes for super-antigens seems to be a frequent and habitual trait of S. aureus more so in MRSA. (author)

  15. Integration and inheritance stability of foreign Bt toxin gene in the bivalent insectresistant transgenic cotton plants

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Genetic and expressional stability of Bt toxin gene is crucial for the breeding of insect-resistant transgenic cotton varieties and their commercialization. Genomic Southern blot analysis of R3, R4 and R5 generations of bivalent transgenic insect-resistant cotton plants was done in order to determine the integration, the copy number and the inheritance stability of Bt toxin gene in the transgenic cotton plants. The results indicated that there was a 4.7 kb positive band in the Southern blot when the genomic DNA of the bivalent transgenic insect-resistant cotton plants and the positive control (the plasmid) were digested with HindⅢ respectively. This result proved that the Bt toxin gene had been integrated into the genome of the cotton in full length.There is only one Xho I restriction site in the Bt toxin gene.Southern blot analysis indicated that many copies of Bt toxin gene had been integrated into the genome of the cotton when the genomic DNA of transgenic plants was digested with Xho I. Among them, there were four copies (about 17.7, 8,5.5 and 4.7 kb in size) existing in all the tested plants of R3,R4 and R5 generations. The preliminary conclusion was that there were more than four copies of Bt toxin gene integrated into the genome of the cotton, among them, more than one copy can express and inherit steadily. This result provides a scientific basis for the breeding of the bivalent insect-resistant transgenic cotton plants and its commercialization.``

  16. Cytolytic Toxin and Related Genes in Bacillus thuringiensis

    Institute of Scientific and Technical Information of China (English)

    QI Dong-lai; LI Yi-dan; GAO Ji-guo

    2005-01-01

    Bacillus thuringiensis is a ubiquitous gram-positive, spore-forming bacterium that forms parasporal crystal during the stationary phase of its growth cycle. These crystal proteins, including Cry and Cyt protein, are toxic to certain insects. Lately, some problems about Cyt classification, structural characteristic, action mechanism and resistance to Cyt toxin are becoming new hotspots. We review the progress of above problems in several foreign labs.

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

    Directory of Open Access Journals (Sweden)

    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

  19. Real-Time Fluorescence PCR Assays for Detection and Characterization of Shiga Toxin, Intimin, and Enterohemolysin Genes from Shiga Toxin-Producing Escherichia coli

    OpenAIRE

    Reischl, Udo; Youssef, Mohammad T.; Kilwinski, Jochen; Lehn, Norbert; Zhang, Wen Lan; Karch, Helge; Strockbine, Nancy A.

    2002-01-01

    PCR assays have proved useful for detecting and characterizing Shiga toxin-producing Escherichia coli (STEC). Recent advances in PCR technology have facilitated the development of real-time fluorescence PCR assays with greatly reduced amplification times and improved methods for the detection of amplified target sequences. We developed and evaluated two such assays for the LightCycler instrument: one that simultaneously detects the genes for Shiga toxins 1 and 2 (stx1 and stx2) and another th...

  20. Bioenergetics and gene silencing approaches for unraveling nucleotide recognition by the human EIF2C2/Ago2 PAZ domain.

    Directory of Open Access Journals (Sweden)

    Mahmoud Kandeel

    Full Text Available Gene silencing and RNA interference are major cellular processes that control gene expression via the cleavage of target mRNA. Eukaryotic translation initiation factor 2C2 (EIF2C2, Argonaute protein 2, Ago2 is considered to be the major player of RNAi as it is the core component of RISC complexes. While a considerable amount of research has focused on RNA interference and its associated mechanisms, the nature and mechanisms of nucleotide recognition by the PAZ domain of EIF2C2/Ago2 have not yet been characterized. Here, we demonstrate that the EIF2C2/Ago2 PAZ domain has an inherent lack of binding to adenine nucleotides, a feature that highlights the poor binding of 3'-adenylated RNAs with the PAZ domain as well as the selective high trimming of the 3'-ends of miRNA containing adenine nucleotides. We further show that the PAZ domain selectively binds all ribonucleotides (except adenosine, whereas it poorly recognizes deoxyribonucleotides. In this context, the modification of dTMP to its ribonucleotide analogue gave a drastic improvement of binding enthalpy and, hence, binding affinity. Additionally, higher in vivo gene silencing efficacy was correlated with the stronger PAZ domain binders. These findings provide new insights into the nature of the interactions of the EIF2C2/Ago2 PAZ domain.

  1. Effects of myostatin propeptide gene tranfection on glucose metabolism in cultured C2C12 cells

    Institute of Scientific and Technical Information of China (English)

    张莎莎

    2014-01-01

    Objective To investigate the effects of recombinant adeno-associated virus-mediated myostatin propeptide(MPRO)on uptake and oxidation of glucose,and glycogen synthesis in C2C12 myotubes,as well as the associated molecular mechanism.Methods Mature C2C12myotubes were assigned to the following 6 groups:control,insulin,green fluorescent protein(GFP),insulin+

  2. Prevalence of Shiga toxin genes and intimin genes in uropathogenic Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Kobra Abbasi; Elahe Tajbakhsh

    2015-01-01

    Objective:To identifystx1, stx2 andeaeA genes inEscherichia coli (E. coli) strains isolated from urine samples in Shahrekord, Iran. Methods: In this cross study a total of 147 middle urine samples from patients with symptoms of urinary tract infection (UTI), referred to clinical laboratories of Shahrekord were studied. Taken samples were cultured to detect Shigatoxin-producing strains and finally 76E. coli isolates were identified using the standard biochemical tests as well as the selective and differential media. The multiplexPCR method was used to evaluate the presence ofstx1, stx2 andeaeA genes.DNA bacteria extraction was performed by boiling and thenPCR was performed in the presence of specific primers. Results: A total of 147 urine samples were collected from patients with suspectedUTI, and 76 samples (51.70%) were diagnosed withE. coli. Among 76 studied isolations ofE. coli, 3 (3.94%) had a positive reaction to lactose and negative reaction to sorbitol. In the female gender,stx1 gene that shown in the samples was related to 30–39 age group. In the other sample related to 20–29 age group,stx1 andeaeA gene were shown. But in male genderstx1 gene was reported in the sample related to 40–49 age group.stx1, stx2 andeaeA genes were not observed together in any samples. Conclusions: Isolation of Shiga toxin-producingE. coli strains has great importance because of the possibility of clinical complications such as hemolytic-uremic syndrome.

  3. Molecular cloning and expression of gene fragments from corynebacteriophage beta encoding enzymatically active peptides of diphtheria toxin.

    OpenAIRE

    Tweten, R K; Collier, R J

    1983-01-01

    Two restriction fragments from corynebacteriophage beta vir tox+ that encode peptides similar to diphtheria toxin fragment A and the chain termination fragment, CRM45, have been cloned into Escherichia coli in plasmid pBR322. Clones containing the recombinant plasmids produced gene products that were active in catalyzing the ADP ribosylation of elongation factor 2 and were reactive with diphtheria toxin antiserum. Toxin-related peptides were found primarily in the periplasmic compartment and ...

  4. Detection of Clostridium perfringens alpha toxin gene in lambs by loop mediated isothermal amplification

    OpenAIRE

    B. Radhika; N. Vinod Kumar; Sreenivasulu, D.

    2016-01-01

    Aim: The loop mediated isothermal amplification (LAMP) was standardized for rapid detection of Clostridium perfringens. Materials and Methods: A total of 120 fecal samples were collected from enterotoxemia suspected lambs were used for screening of C. perfringens cpa gene by LAMP. The specificity of the LAMP amplified products was tested by digesting with restriction enzyme XmnI for alpha toxin gene. Results: Out of 120 samples screened 112 (93.3%) samples were positive by both LAMP and polym...

  5. Insecticidal toxins from Bacillus thuringiensis subsp. kenyae: gene cloning and characterization and comparison with B. thuringiensis subsp. kurstaki CryIA(c) toxins.

    OpenAIRE

    Von Tersch, M A; Robbins, H L; Jany, C S; Johnson, T B

    1991-01-01

    Genes encoding insecticidal crystal proteins were cloned from three strains of Bacillus thuringiensis subsp. kenyae and two strains of B. thuringiensis subsp. kurstaki. Characterization of the B. thuringiensis subsp. kenyae toxin genes showed that they are most closely related to cryIA(c) from B. thuringiensis subsp. kurstaki. The cloned genes were introduced into Bacillus host strains, and the spectra of insecticidal activities of each Cry protein were determined for six pest lepidopteran in...

  6. 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.

  7. New multiplex PCR method for the detection of Clostridium difficile toxin A (tcdA) and toxin B (tcdB) and the binary toxin (cdtA/cdtB) genes applied to a Danish strain collection.

    Science.gov (United States)

    Persson, S; Torpdahl, M; Olsen, K E P

    2008-11-01

    Isolates of Clostridium difficile from 159 hospitalized Danish patients (2005) were analysed by a new 5-plex PCR method targeting the toxin genes tcdA, tcdB, cdtA and cdtB, and 16S rDNA as an internal positive control. Additionally, the toxin-regulating gene tcdC was partially sequenced by a new sequencing-based method that revealed genetic changes that may render the gene product inactive. Finally tcdA was analysed using a previously published method for the detection of internal deletions. The 5-plex PCR revealed four different toxin gene profiles: 36 tcdA+, tcdB+, cdtA+/cdtB+; one tcdA+, tcdB-, cdtA+/cdtB+; 98 tcdA+, tcdB+, cdtA-/cdtB-; and 24 non-toxigenic tcdA-, tcdB-, cdtA-/cdtB-. Deletion studies revealed that 26 strains contained a c. 700-bp deletion in tcdA, and 39 strains contained at least one possible inactivation feature in tcdC. The prevalence of the binary toxin genes was 23%. All strains with the tcdA+, tcdB+, cdtA+/cdtB+ profile were investigated by PCR ribotyping, and this revealed eight different ribotypes, none of which were 027. The 5-plex PCR method offers a one-step, rapid and specific screening method for C. difficile toxin genes. This toxin gene profiling, together with deletion studies in tcdA and tcdC, may allow an evaluation of the pathogenic potential of C. difficile. PMID:19040478

  8. Botulinum toxin.

    OpenAIRE

    Savardekar Preeti

    1989-01-01

    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, 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...

  9. Detection of Shiga toxin variants, virulence genes and the relationship to cytotoxicity in Shiga toxin-producing Escherichia coli (STEC) from domestic farm animals

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli (STEC) can cause foodborne illnesses ranging from diarrhea to life-threating diseases such as hemorrhagic colitis, and hemolytic uremic syndrome in humans. In this study, we determined virulence genes, stx subtypes and we evaluated the cytotoxicity in STEC stra...

  10. The gene for type A streptococcal exotoxin (erythrogenic toxin) is located in bacteriophage T12.

    OpenAIRE

    Weeks, C R; Ferretti, J J

    1984-01-01

    The infection of Streptococcus pyogenes T25(3) with the temperate bacteriophage T12 results in the conversion of the nontoxigenic strain to type A streptococcal exotoxin (erythrogenic toxin) production. Although previous research has established that integration of the bacteriophage genome into the host chromosome is not essential for exotoxin production, the location of the gene on the bacteriophage or bacterial chromosome had not been determined. In the present investigation, recombinant DN...

  11. Polyketide synthesis genes associated with toxin production in two species of Gambierdiscus (Dinophyceae)

    OpenAIRE

    Kohli, Gurjeet S.; John, Uwe; Figueroa, Rosa I.; Rhodes, Lesley L.; Harwood, D. Tim; Groth, Marco; Bolch, Christopher J. S.; Murray, Shauna A.

    2015-01-01

    Background Marine microbial protists, in particular, dinoflagellates, produce polyketide toxins with ecosystem-wide and human health impacts. Species of Gambierdiscus produce the polyether ladder compounds ciguatoxins and maitotoxins, which can lead to ciguatera fish poisoning, a serious human illness associated with reef fish consumption. Genes associated with the biosynthesis of polyether ladder compounds are yet to be elucidated, however, stable isotope feeding studies of such compounds co...

  12. Toxic peptides and genes encoding toxin gamma of the Brazilian scorpions Tityus bahiensis and Tityus stigmurus.

    Science.gov (United States)

    Becerril, B; Corona, M; Coronas, F I; Zamudio, F; Calderon-Aranda, E S; Fletcher, P L; Martin, B M; Possani, L D

    1996-02-01

    Seven toxic peptides from the venom of Tityus bahiensis and Tityus stigmurus was isolated and sequenced, five of them to completion. The most abundant peptide from each of these two species of scorpion was 95% identical with that of toxin gamma from the venom of Tityus serrulatus. They were consequently named gamma-b and gamma-st respectively. The genes encoding these new gamma-like peptides were cloned and sequenced by utilizing oligonucleotides synthesized according to known cDNA sequences of toxin gamma, and amplified by PCR on templates of DNA purified from both T. bahiensis and T. stigmurus. They contain an intron of approx. 470 bp. Possible mechanisms of processing and expressing these peptides are discussed, in view of the fact that glycine is the first residue of the N-terminal sequence of T. stigmurus, whereas lysine is the residue at position 1 of toxin gamma from T. serrulatus and T. bahiensis. In addition, chemical characterization of the less abundant toxic peptides showed the presence of at least four distinct families of peptides in all three species of the genus Tityus studied. There is a large degree of similarity among peptides from different venoms of the same family. By using specific horse and rabbit antisera, the venoms of T. bahiensis, T. serrulatus and T. stigmurus were compared. They showed an extended degree of cross-reactivity. Thus these three species of scorpion have similar toxic components, the genes of which are similarly organized, processed and expressed. PMID:8611151

  13. Investigation of toxin gene diversity and antimicrobial resistance of Clostridium difficile strains.

    Science.gov (United States)

    Zhu, Shanshan; Zhang, Huaping; Zhang, Xinsheng; Wang, Chao; Fan, Guangming; Zhang, Weifeng; Sun, Gang; Chen, Huihong; Zhang, Liming; Li, Zhaoyun

    2014-09-01

    The incidence of Clostridium difficile infection (CDI) has been previously reported in a number of studies. However, data collected from the Chinese population is limited. In the present study, the diversity of the toxin genes, tcdA and tcdB, of 57 Clostridium difficile (C. difficile) isolates from a Chinese population were investigated by polymerase chain reaction (PCR) (38 A(+)B(+), 14 A(-)B(+) and 5 A(-)B(-)). Quantitative PCR was used to check the expression of these two genes and it was found that the genes were not expressed by all the strains. The absence of tcdA or tcdB expression in certain strains could be due to the lower expression of tcdD and the higher expression of tcdC, which are positive and negative regulators for these two toxin genes, respectively. In addition, the antimicrobial susceptibilities of 57 isolates were investigated. Therefore, these data would aid in the future prevention of CDI outbreaks and improve the understanding of the infection. PMID:25054021

  14. 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...

  15. The lethal toxin from Australian funnel-web spiders is encoded by an intronless gene.

    Directory of Open Access Journals (Sweden)

    Sandy Steffany Pineda

    Full Text Available Australian funnel-web spiders are generally considered the most dangerous spiders in the world, with envenomations from the Sydney funnel-web spider Atrax robustus resulting in at least 14 human fatalities prior to the introduction of an effective anti-venom in 1980. The clinical envenomation syndrome resulting from bites by Australian funnel-web spiders is due to a single 42-residue peptide known as δ-hexatoxin. This peptide delays the inactivation of voltage-gated sodium channels, which results in spontaneous repetitive firing and prolongation of action potentials, thereby causing massive neurotransmitter release from both somatic and autonomic nerve endings. Here we show that δ-hexatoxin from the Australian funnel-web spider Hadronyche versuta is produced from an intronless gene that encodes a prepropeptide that is post-translationally processed to yield the mature toxin. A limited sampling of genes encoding unrelated venom peptides from this spider indicated that they are all intronless. Thus, in distinct contrast to cone snails and scorpions, whose toxin genes contain introns, spiders may have developed a quite different genetic strategy for evolving their venom peptidome.

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

    International Nuclear Information System (INIS)

    Highlights: • AOX1 contributes to the formation of myotube. • Silencing of AOX1 reduces myotube formation. • AOX1 regulates MyoG gene expression. • AOX1 contributes to myogenesis via H2O2. - 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 AOX1kd cells. Expression of myogenin (MYOG), one of the marker genes used to study myogenesis, was also found to be reduced in AOX1kd cells. AOX1 is an enzyme of pharmacological and toxicological importance that metabolizes numerous xenobiotics to their respective carboxylic acids. Hydrogen peroxide (H2O2) 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 H2O2 among AOX1kd cells confirmed production of H2O2 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 H2O2

  17. 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}.

  18. Distribution of Shiga toxin genes subtypes in B phylotypes of Escherichia coli isolated from calves suffering from diarrhea in Tehran suburb using DNA oligonucleotide arrays

    Directory of Open Access Journals (Sweden)

    Hamid Staji

    2015-11-01

    Full Text Available Background and Objectives: Shiga toxin-producing Escherichia coli (STEC have emerged as human pathogens and con- tamination via animal origin has been a major public health concern. We compared the distribution of phylogenetic groups and prevalence of stx gene variants among the pathogenic strains of Escherichia coli isolated from feces of diarrheatic calves in Tehran suburb farms.Materials and Methods: In this study we screened 140 diarrheatic calves (1-15 days old for E. coli strains during a 3 months period of time. The isolated strains were grouped into different phylotypes according to the presence of chuA, yjaA and TSPE4.C2 genes. Then, the prevalence of stx gene subtypes was evaluated in the B  phylotypes.Results: From diarrheatic calves, 51 bacterial isolates were biochemically identified as E. coli and 31 isolates out of 51 were considered B  phylotype using DNA Microarray technology. Of these isolates, 20 contained stx a and stx b and one harbored all mentioned variants of stx genes except stx b.Conclusion: This study showed that in Tehran suburb, the B  phylotype of E. coli is prevalent as a causative agent of diarrhea in calves and the prevalence of stx  gene subtypes is dominant in comparison with other subtypes. Considering the possibility that these stx genes can be spread to other strains, bovine E. coli strains are an important source of stx genes for other strains and further study and surveillance seems to be required for the exact identification of virulence profile of E. coli phylotypes in different hosts.Keywords: Escherichia coli, calf diarrhea, B1 phylotype, shiga-like toxin subtypes, Tehran suburb

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

    Directory of Open Access Journals (Sweden)

    BruceAlanWatkins

    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

  20. The axe-txe complex of Enterococcus faecium presents a multilayered mode of toxin-antitoxin gene expression regulation.

    Directory of Open Access Journals (Sweden)

    Lidia Boss

    Full Text Available Multidrug-resistant variants of human pathogens from the genus Enterococcus represent a significant health threat as leading agents of nosocomial infections. The easy acquisition of plasmid-borne genes is intimately involved in the spread of antibiotic resistance in enterococci. Toxin-antitoxin (TA systems play a major role in both maintenance of mobile genetic elements that specify antibiotic resistance, and in bacterial persistence and virulence. Expression of toxin and antitoxin genes must be in balance as inappropriate levels of toxin can be dangerous to the host. The controlled production of toxin and antitoxin is usually achieved by transcriptional autoregulation of TA operons. One of the most prevalent TA modules in enterococcal species is axe-txe which is detected in a majority of clinical isolates. Here, we demonstrate that the axe-txe cassette presents a complex pattern of gene expression regulation. Axe-Txe cooperatively autorepress expression from a major promoter upstream of the cassette. However, an internal promoter that drives the production of a newly discovered transcript from within axe gene combined with a possible modulation in mRNA stability play important roles in the modulation of Axe:Txe ratio to ensure controlled release of the toxin.

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

    Directory of Open Access Journals (Sweden)

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Effects of a natural toxin on life history and gene expression of Eisenia andrei.

    Science.gov (United States)

    van Ommen Kloeke, A E Elaine; Gong, Ping; Ellers, Jacintha; Roelofs, Dick

    2014-02-01

    Earthworms perform key functions for a healthy soil ecosystem, such as bioturbation. The soil ecosystem can be challenged by natural toxins such as isothiocyanates (ITCs), produced by many commercial crops. Therefore, the effects of 2-phenylethyl ITC were investigated on the earthworm Eisenia andrei using an ecotoxicogenomics approach. Exposure to 2-phenylethyl ITC reduced both survival and reproduction of E. andrei in a dose-dependent manner (median effective concentration [EC50] = 556 nmol/g). Cross-species comparative genomic hybridization validated the applicability of an existing 4 × 44,000 Eisenia fetida microarray to E. andrei. Gene expression profiles revealed the importance of metallothionein (MT) as an early warning signal when E. andrei was exposed to low concentrations of 2-phenylethyl ITC. Alignment of these MT genes with the MT-2 gene of Lumbricus rubellus showed that at least 2 MT gene clusters are present in the Eisenia sp. genome. At high-exposure concentrations, gene expression was mainly affected by inhibiting chitinase activity, inducing an oxidative stress response, and stimulating energy metabolism. Furthermore, analysis by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway implied that the high concentration may have caused impaired light sensitivity, angiogenesis, olfactory perception, learning, and memory. Increased levels of ITCs may be found in the field in the near future. The results presented call for a careful investigation to quantify the risk of such compounds before allowing them to enter the soil on a large scale. PMID:24395740

  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. 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

  6. 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...... 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....... 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....

  7. 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.

  8. Electrochemical DNA sensor for anthrax toxin activator gene atxA-detection of PCR amplicons.

    Science.gov (United States)

    Das, Ritu; Goel, Ajay K; Sharma, Mukesh K; Upadhyay, Sanjay

    2015-12-15

    We report the DNA probe functionalized electrochemical genosensor for the detection of Bacillus anthracis, specific towards the regulatory gene atxA. The DNA sensor is fabricated on electrochemically deposited gold nanoparticle on self assembled layer of (3-Mercaptopropyl) trimethoxysilane (MPTS) on GC electrode. DNA hybridization is monitored by differential pulse voltammogram (DPV). The modified GC electrode is characterized by atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) method. We also quantified the DNA probe density on electrode surface by the chronocoulometric method. The detection is specific and selective for atxA gene by DNA probe on the electrode surface. No report is available for the detection of B. anthracis by using atxA an anthrax toxin activator gene. In the light of real and complex sample, we have studied the PCR amplicons of 303, 361 and 568 base pairs by using symmetric and asymmetric PCR approaches. The DNA probe of atxA gene efficiently hybridizes with different base pairs of PCR amplicons. The detection limit is found to be 1.0 pM (S/N ratio=3). The results indicate that the DNA sensor is able to detect synthetic target as well as PCR amplicons of different base pairs. PMID:26257186

  9. Characterization of foodborne Staphylococcus aureus isolates: association of toxin gene profile with genotype and food commodities in Shanghai, China

    Science.gov (United States)

    Staphylococcus aureus is an important clinical and foodborne pathogen. Zoonotic risk of transmission to humans highlights the need to understand the ecology of S. aureus in various foods. We characterized the genetic diversity and the distribution of 25 toxin genes in 142 foodborne Staphylococcus au...

  10. Usefulness of Adjunctive Fecal Calprotectin and Serum Procalcitonin in Individuals Positive for Clostridium difficile Toxin Gene by PCR Assay

    OpenAIRE

    Kristin Y Popiel; Gheorghe, Romina; Eastmond, Jennifer; Miller, Mark A.

    2015-01-01

    In 54/64 subjects with nosocomial diarrhea, fecal calprotectin levels correlated with the results of stool samples tested for Clostridium difficile toxin gene by PCR. Fecal calprotectin levels can be used as an adjunctive measure to PCR to support the diagnosis of C. difficile infection.

  11. Usefulness of Adjunctive Fecal Calprotectin and Serum Procalcitonin in Individuals Positive for Clostridium difficile Toxin Gene by PCR Assay.

    Science.gov (United States)

    Popiel, Kristin Y; Gheorghe, Romina; Eastmond, Jennifer; Miller, Mark A

    2015-11-01

    In 54/64 subjects with nosocomial diarrhea, fecal calprotectin levels correlated with the results of stool samples tested for Clostridium difficile toxin gene by PCR. Fecal calprotectin levels can be used as an adjunctive measure to PCR to support the diagnosis of C. difficile infection. PMID:26354814

  12. Urease genes in non-O157 Shiga toxin-producing Escherichia coli : mostly silent but valuable markers for pathogenicity

    NARCIS (Netherlands)

    Friedrich, A W; Lukas, R; Mellmann, A; Köck, R; Zhang, W; Mathys, W; Bielaszewska, M; Karch, H

    2006-01-01

    The distribution of ureC was investigated among 294 Escherichia coli isolates, comprising 72 strains from the E. coli standard reference collection (ECOR), 62 strains from the diarrhoeagenic E. coli (DEC) collection, and 160 clinical isolates of Shiga toxin-producing E. coli (STEC). The ureC gene wa

  13. A chloroplast DNA deletion located in RNA polymerase gene rpoC2 in CMS lines of sorghum.

    Science.gov (United States)

    Chen, Z; Muthukrishnan, S; Liang, G H; Schertz, K F; Hart, G E

    1993-01-01

    Fertile lines of sorghum (Sorghum bicolor) were shown to differ from cytoplasmic male sterile (CMS) lines by the presence of a 3.8 kb HindIII chloroplast DNA fragment in the former and a smaller (3.7 kb) fragment in the latter. DNA/DNA hybridization studies showed that these two fragments are homologous. Fertile plants from S. versicolor, S. almum, S. halepense, and Sorghastrum nutans (Yellow Indiangrass) also have the 3.8 kb fragment, and CMS lines studied containing A1, A2 and A3 cytoplasms have the 3.7 kb fragment. The size difference between the two fragments was localized to a 1.0 kb SacI-HindIII fragment by restriction mapping. A 165 bp deletion, which is flanked by a 51 bp tandem repeat, was identified in the CMS lines by sequencing the clones. Comparison of the two sequences with those from maize, rice, tobacco, spinach, pea, and liverwort revealed that the deleted sequence is located in the middle of the RNA polymerase beta" subunit encoded by the gene rpoC2. The amino acid sequence deleted in the CMS lines is in a monocot-specific region which contains two protein motifs that are characteristic of several transcriptional activation factors, namely, a leucine zipper motif and an acidic domain capable of forming an amphipathic alpha-helix. Further studies designed to determine whether or not the deletion is involved in CMS of sorghum are underway. PMID:8437572

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

    OpenAIRE

    Ji-Sun Jung; Young-Ho Ahn; Byung-In Moon; Hee-Sun Kim

    2016-01-01

    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 t...

  15. Development of a Real-Time Fluorescence PCR Assay for Rapid Detection of the Diphtheria Toxin Gene

    OpenAIRE

    Mothershed, Elizabeth A.; Cassiday, Pamela K.; Pierson, Kevin; Mayer, Leonard W.; Popovic, Tanja

    2002-01-01

    We developed and evaluated a real-time fluorescence PCR assay for detecting the A and B subunits of diphtheria toxin (tox) gene. When 23 toxigenic Corynebacterium diphtheriae strains, 9 nontoxigenic C. diphtheriae strains, and 44 strains representing the diversity of pathogens and normal respiratory flora were tested, this real-time PCR assay exhibited 100% sensitivity and specificity. It allowed for the detection of both subunits of the tox gene at 750 times greater sensitivity (2 CFU) than ...

  16. MvirDB—a microbial database of protein toxins, virulence factors and antibiotic resistance genes for bio-defence applications

    OpenAIRE

    Zhou, C. E.; Smith,J; Lam, M.; Zemla, A.; Dyer, M. D.; Slezak, T.

    2006-01-01

    Knowledge of toxins, virulence factors and antibiotic resistance genes is essential for bio-defense applications aimed at identifying ‘functional’ signatures for characterizing emerging or engineered pathogens. Whereas genetic signatures identify a pathogen, functional signatures identify what a pathogen is capable of. To facilitate rapid identification of sequences and characterization of genes for signature discovery, we have collected all publicly available (as of this writing), organized ...

  17. Identification of deoxyribonucleic acid restriction fragments of beta-converting corynebacteriophages that carry the gene for diphtheria toxin.

    OpenAIRE

    Buck, G A; Groman, N B

    1981-01-01

    Deoxyribonucleic acid fragments bearing the gene for diphtheria toxin have been identified in restriction enzyme digests of deoxyribonucleic acids from beta-converting and gamma-nonconverting corynebacteriophages. A combination of physical and genetic evidence has established that the Bam HI band C fragment of beta phage deoxyribonucleic acid, which carries the specific phage attachment site (Buck and Groman, J. Bacteriol. 148:131-142, 1981), also carries most, and probably all, of the gene f...

  18. Variant forms of the binary toxin CDT locus and tcdC gene in Clostridium difficile strains.

    Science.gov (United States)

    Stare, Barbara Geric; Delmée, Michel; Rupnik, Maja

    2007-03-01

    Variability in the genes for toxin A, toxin B and other pathogenicity locus regions is well known and is the basis for the distribution of Clostridium difficile strains into variant toxinotypes. Previous data have indicated that some C. difficile strains have a non-functional truncated form of the binary toxin (CDT) locus. This study analysed variability in the CDT locus and the presence of deleted tcdC genes in C. difficile strains. A total of 146 strains were screened, including known variant toxinotypes and non-variant A+B+ (toxinotype 0) and A-B- C. difficile strains. In all of the strains studied, only two forms of the CDT locus were found: a full-length 4.3 kb fragment encoding the functional binary toxin or a truncated 2.3 kb fragment. Whilst the full-length CDT locus was found almost exclusively in variant toxinotypes, the truncated form was detected in 79% of toxinotype 0 strains. Non-toxinogenic A-B- strains with a truncated version were not found and only rarely possessed the full-length CDT locus (A-B-CDT+ strains). Four different forms of the tcdC gene were found; three represented deleted versions and typically were found in toxinotypes III-VII, XI, XIV-XVI and XXIV. PMID:17314362

  19. Expression of porcine CFL2b gene in C2C12 cells and its effect on the expression of MyHC

    Directory of Open Access Journals (Sweden)

    ZHAO Wei

    2008-12-01

    Full Text Available Porcine CFL2b gene is expressed mainly in skeletal muscle, it affects muscle development and myofibrillar formation. In order to study the relationship between CFL2b gene and muscle fiber trait, stable C2C12 cell clones groups expressing porcine CFL2b gene were obtained by directed cloning and gene transfection technology. The expression of pEGFP-N1–CFL2b were detected using GFP fluorescence and Western Blotting. The expression level of myosin heavy chain (MyHC isoforms (2x.2b and slow in C2C12 were determined using Real-time PCR. Result showed that MyHC 2x gene and MyHC 2b genes were obviously up-regulated, MyHC1/slow gene not significant. The research indicated porcine CFL2b gene correlated to muscle fiber trait. And it was associated with pork quality. Porcine CFL2b gene can possible be regarded as a candidate gene for pork quality [Acta Zoologica Sinica 54(6: 1014–1019, 2008].

  20. 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

    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...

  1. Expression of porcine CFL2b gene in C2C12 cells and its effect on the expression of MyHC

    OpenAIRE

    Zhao, Wei; ZENG Rui-Xia; Su, Yu-Hong; BA Cai-Feng; SU Rong-Jian; Song, Hui-Juan

    2008-01-01

    Porcine CFL2b gene is expressed mainly in skeletal muscle, it affects muscle development and myofibrillar formation. In order to study the relationship between CFL2b gene and muscle fiber trait, stable C2C12 cell clones groups expressing porcine CFL2b gene were obtained by directed cloning and gene transfection technology. The expression of pEGFP-N1–CFL2b were detected using GFP fluorescence and Western Blotting. The expression level of myosin heavy chain (MyHC) isoforms (2x.2b and slow) in C...

  2. Impact of Nitrogen Sources on Gene Expression and Toxin Production in the Diazotroph Cylindrospermopsis raciborskii CS-505 and Non-Diazotroph Raphidiopsis brookii D9

    Directory of Open Access Journals (Sweden)

    Karina Stucken

    2014-06-01

    Full Text Available Different environmental nitrogen sources play selective roles in the development of cyanobacterial blooms and noxious effects are often exacerbated when toxic cyanobacteria are dominant. Cylindrospermopsis raciborskii CS-505 (heterocystous, nitrogen fixing and Raphidiopsis brookii D9 (non-N2 fixing produce the nitrogenous toxins cylindrospermopsin (CYN and paralytic shellfish toxins (PSTs, respectively. These toxin groups are biosynthesized constitutively by two independent putative gene clusters, whose flanking genes are target for nitrogen (N regulation. It is not yet known how or if toxin biosynthetic genes are regulated, particularly by N-source dependency. Here we show that binding boxes for NtcA, the master regulator of N metabolism, are located within both gene clusters as potential regulators of toxin biosynthesis. Quantification of intra- and extracellular toxin content in cultures at early stages of growth under nitrate, ammonium, urea and N-free media showed that N-sources influence neither CYN nor PST production. However, CYN and PST profiles were altered under N-free medium resulting in a decrease in the predicted precursor toxins (doCYN and STX, respectively. Reduced STX amounts were also observed under growth in ammonium. Quantification of toxin biosynthesis and transport gene transcripts revealed a constitutive transcription under all tested N-sources. Our data support the hypothesis that PSTs and CYN are constitutive metabolites whose biosynthesis is correlated to cyanobacterial growth rather than directly to specific environmental conditions. Overall, the constant biosynthesis of toxins and expression of the putative toxin-biosynthesis genes supports the usage of qPCR probes in water quality monitoring of toxic cyanobacteria.

  3. Impact of Nitrogen Sources on Gene Expression and Toxin Production in the Diazotroph Cylindrospermopsis raciborskii CS-505 and Non-Diazotroph Raphidiopsis brookii D9

    Science.gov (United States)

    Stucken, Karina; John, Uwe; Cembella, Allan; Soto-Liebe, Katia; Vásquez, Mónica

    2014-01-01

    Different environmental nitrogen sources play selective roles in the development of cyanobacterial blooms and noxious effects are often exacerbated when toxic cyanobacteria are dominant. Cylindrospermopsis raciborskii CS-505 (heterocystous, nitrogen fixing) and Raphidiopsis brookii D9 (non-N2 fixing) produce the nitrogenous toxins cylindrospermopsin (CYN) and paralytic shellfish toxins (PSTs), respectively. These toxin groups are biosynthesized constitutively by two independent putative gene clusters, whose flanking genes are target for nitrogen (N) regulation. It is not yet known how or if toxin biosynthetic genes are regulated, particularly by N-source dependency. Here we show that binding boxes for NtcA, the master regulator of N metabolism, are located within both gene clusters as potential regulators of toxin biosynthesis. Quantification of intra- and extracellular toxin content in cultures at early stages of growth under nitrate, ammonium, urea and N-free media showed that N-sources influence neither CYN nor PST production. However, CYN and PST profiles were altered under N-free medium resulting in a decrease in the predicted precursor toxins (doCYN and STX, respectively). Reduced STX amounts were also observed under growth in ammonium. Quantification of toxin biosynthesis and transport gene transcripts revealed a constitutive transcription under all tested N-sources. Our data support the hypothesis that PSTs and CYN are constitutive metabolites whose biosynthesis is correlated to cyanobacterial growth rather than directly to specific environmental conditions. Overall, the constant biosynthesis of toxins and expression of the putative toxin-biosynthesis genes supports the usage of qPCR probes in water quality monitoring of toxic cyanobacteria. PMID:24956074

  4. Real-time PCR quantification of the AM-toxin gene and HPLC qualification of toxigenic metabolites from Alternaria species from apples.

    Science.gov (United States)

    Andersen, Birgitte; Smedsgaard, Jørn; Jørring, Ida; Skouboe, Pernille; Pedersen, Lars Hagsholm

    2006-09-01

    Some Alternaria species are able to produce plant pathogenic as well as toxic metabolites. In both agriculture and the food industry it is important know if toxigenic Alternaria are present to rapidly employ the correct corrective actions. The purpose of this work was to establish a real-time PCR method, which can detect and quantify apple pathogenic and toxigenic Alternaria. An AM-toxin I primer set, which could recognize Alternaria DNA only, was designed by using primers complementary to the AM-toxin I gene. The method could detect small amounts of DNA (4 pg) and still obtain a large dynamic range (4 decades) without interference from apple material. Eight Alternaria isolates were analyzed for the presence of AM-toxin I gene and their production of secondary metabolites. Then analyses showed that all eight isolates contained the AM toxin gene and were able to produce the plant pathogenic tentoxin in addition to AM toxin I. The analyses also showed the production of tenuazonic acid, alternariols, Altenuene, altenusin and/or altertoxin I in pure culture. Analyses of inoculated apples showed that both the AM-toxin gene and alternariol monomethyl ether could be detected. Morphological analyses suggested that the eight Alternaria strains, though they all carried the AM toxin genes, probably belong to different but closely related un-described Alternaria taxa in the A. tenuissima species-group based on morphological and chemical differences. PMID:16890318

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

    OpenAIRE

    Johansson K-E; Frey J; Engström BE; Johansson A; Båverud V

    2005-01-01

    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 investig...

  6. Prevalence of Shiga toxin genes and intimin genes in uropathogenic Escherichia coli

    OpenAIRE

    Kobra Abbasi; Elahe Tajbakhsh

    2015-01-01

    Objective: To identify stx1, stx2 and eaeA genes in Escherichia coli (E. coli) strains isolated from urine samples in Shahrekord, Iran. Methods: In this cross study a total of 147 middle urine samples from patients with symptoms of urinary tract infection (UTI), referred to clinical laboratories of Shahrekord were studied. Taken samples were cultured to detect Shigatoxin-producing strains and finally 76 E. coli isolates were identified using the standard biochemical tests as we...

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

    OpenAIRE

    Ostermaier Veronika; Schanz Ferdinand; Köster Oliver; Kurmayer Rainer

    2012-01-01

    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...

  8. The sxt Gene and Paralytic Shellfish Poisoning Toxins as Markers for the Monitoring of Toxic Alexandrium Species Blooms.

    Science.gov (United States)

    Penna, Antonella; Perini, Federico; Dell'Aversano, Carmela; Capellacci, Samuela; Tartaglione, Luciana; Giacobbe, Maria Grazia; Casabianca, Silvia; Fraga, Santiago; Ciminiello, Patrizia; Scardi, Michele

    2015-12-15

    Paralytic shellfish poisoning (PSP) is a serious human illness caused by the ingestion of seafood contaminated with saxitoxin and its derivatives (STXs). These toxins are produced by some species of marine dinoflagellates within the genus Alexandrium. In the Mediterranean Sea, toxic Alexandrium spp. blooms, especially of A. minutum, are frequent and intense with negative impact to coastal ecosystem, aquaculture practices and other economic activities. We conducted a large scale study on the sxt gene and toxin distribution and content in toxic dinoflagellate A. minutum of the Mediterranean Sea using both quantitative PCR (qPCR) and HILIC-HRMS techniques. We developed a new qPCR assay for the estimation of the sxtA1 gene copy number in seawater samples during a bloom event in Syracuse Bay (Mediterranean Sea) with an analytical sensitivity of 2.0 × 10° sxtA1 gene copy number per reaction. The linear correlation between sxtA1 gene copy number and microalgal abundance and between the sxtA1 gene and STX content allowed us to rapidly determine the STX-producing cell concentrations of two Alexandrium species in environmental samples. In these samples, the amount of sxtA1 gene was in the range of 1.38 × 10(5) - 2.55 × 10(8) copies/L and the STX concentrations ranged from 41-201 nmol/L. This study described a potential PSP scenario in the Mediterranean Sea. PMID:26580419

  9. The ipdC, hisC1 and hisC2 genes involved in indole-3-acetic production used as alternative phylogenetic markers in Azospirillum brasilense.

    Science.gov (United States)

    Jijón-Moreno, Saúl; Marcos-Jiménez, Cynthia; Pedraza, Raúl O; Ramírez-Mata, Alberto; de Salamone, I García; Fernández-Scavino, Ana; Vásquez-Hernández, Claudia A; Soto-Urzúa, Lucia; Baca, Beatriz E

    2015-06-01

    Plant growth-promoting bacteria of the genus Azospirillum are present in the rhizosphere and as endophytes of many crops. In this research we studied 40 Azospirillum strains isolated from different plants and geographic regions. They were first characterized by 16S rDNA restriction analysis, and their phylogenetic position was established by sequencing the genes 16S rDNA, ipdC, hisC1, and hisC2. The latter three genes are involved in the indole-3-pyruvic acid (IPyA) biosynthesis pathway of indole-3-acetic acid (IAA). Furthermore, the suitability of the 16S-23S rDNA intergenic spacer sequence (IGS) for the differentiation of closely related Azospirillum taxa and development of PCR protocols allows for specific detection of strains. The IGS-RFLP analysis enabled intraspecies differentiation, particularly of Azospirillum brasilense and Azospirillum lipoferum strains. Results demonstrated that the ipdC, hisC1, and hisC2 genes are highly conserved in all the assessed A. brasilense isolates, suggesting that these genes can be used as an alternative phylogenetic marker. In addition, IAA production determined by HPLC ranged from 0.17 to 98.2 μg mg(-1) protein. Southern hybridization with the A. brasilense ipdC gene probe did not show, a hybridization signal with A. lipoferum, Azospirillum amazonense, Azospirillum halopreferans and Azospirillum irakense genomic DNA. This suggests that these species produce IAA by other pathways. Because IAA is mainly synthesized via the IPyA pathway in A. brasilense strains, a species that is used worldwide in agriculture, the identification of ipdC, hisC1, and hisC2 genes by PCR may be suitable for selecting exploitable strains. PMID:25842039

  10. Quantitative Prevalence and Toxin Gene Profile of Bacillus cereus from Ready-to-Eat Vegetables in South Korea.

    Science.gov (United States)

    Chon, Jung-Whan; Yim, Jin-Hyeok; Kim, Hong-Seok; Kim, Dong-Hyeon; Kim, Hyunsook; Oh, Deog-Hwan; Kim, Soo-Ki; Seo, Kun-Ho

    2015-09-01

    Ready-to-eat (RTE) foods such as prepared vegetables are becoming an increasingly popular food choice. Since RTE vegetables are not commonly sterilized by heat treatment, contamination with foodborne pathogens such as Bacillus cereus (B. cereus) is a major concern. The objective of this study was to assess the quantitative prevalence and toxin gene profiles of B. cereus strains isolated from RTE vegetables. We found that 70 of the 145 (48%) tested retail vegetable salad and sprout samples were positive for B. cereus. The B. cereus isolates harbored at least one enterotoxin gene. The detection rates of nheABC, hblCDA, cytK, and entFM enterotoxin genes among all isolates were 97.1%, 100%, 81.4%, and 98.6%, respectively. No strain carried the emetic toxin genes. Only 4 strains (5.7%) from the 70 isolates were psychrotrophic and were able to grow at 7°C. All of the psychrotrophic isolates possessed at least 1 enterotoxin gene. PMID:26317539

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

    Directory of Open Access Journals (Sweden)

    Restrepo Nora

    1997-01-01

    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

  12. Carbon-dependent control of electron transfer and central carbon pathway genes for methane biosynthesis in the Archaean, Methanosarcina acetivorans strain C2A

    Directory of Open Access Journals (Sweden)

    Gunsalus Robert P

    2010-02-01

    Full Text Available Abstract Background The archaeon, Methanosarcina acetivorans strain C2A forms methane, a potent greenhouse gas, from a variety of one-carbon substrates and acetate. Whereas the biochemical pathways leading to methane formation are well understood, little is known about the expression of the many of the genes that encode proteins needed for carbon flow, electron transfer and/or energy conservation. Quantitative transcript analysis was performed on twenty gene clusters encompassing over one hundred genes in M. acetivorans that encode enzymes/proteins with known or potential roles in substrate conversion to methane. Results The expression of many seemingly "redundant" genes/gene clusters establish substrate dependent control of approximately seventy genes for methane production by the pathways for methanol and acetate utilization. These include genes for soluble-type and membrane-type heterodisulfide reductases (hdr, hydrogenases including genes for a vht-type F420 non-reducing hydrogenase, molybdenum-type (fmd as well as tungsten-type (fwd formylmethanofuran dehydrogenases, genes for rnf and mrp-type electron transfer complexes, for acetate uptake, plus multiple genes for aha- and atp-type ATP synthesis complexes. Analysis of promoters for seven gene clusters reveal UTR leaders of 51-137 nucleotides in length, raising the possibility of both transcriptional and translational levels of control. Conclusions The above findings establish the differential and coordinated expression of two major gene families in M. acetivorans in response to carbon/energy supply. Furthermore, the quantitative mRNA measurements demonstrate the dynamic range for modulating transcript abundance. Since many of these gene clusters in M. acetivorans are also present in other Methanosarcina species including M. mazei, and in M. barkeri, these findings provide a basis for predicting related control in these environmentally significant methanogens.

  13. A critical role for the cccA gene product, cytochrome c2, in diverting electrons from aerobic respiration to denitrification in Neisseria gonorrhoeae.

    Science.gov (United States)

    Hopper, Amanda C; Li, Ying; Cole, Jeffrey A

    2013-06-01

    Neisseria gonorrhoeae is a microaerophile that, when oxygen availability is limited, supplements aerobic respiration with a truncated denitrification pathway, nitrite reduction to nitrous oxide. We demonstrate that the cccA gene of Neisseria gonorrhoeae strain F62 (accession number NG0292) is expressed, but the product, cytochrome c2, accumulates to only low levels. Nevertheless, a cccA mutant reduced nitrite at about half the rate of the parent strain. We previously reported that cytochromes c4 and c5 transfer electrons to cytochrome oxidase cbb3 by two independent pathways and that the CcoP subunit of cytochrome oxidase cbb3 transfers electrons to nitrite. We show that mutants defective in either cytochrome c4 or c5 also reduce nitrite more slowly than the parent. By combining mutations in cccA (Δc2), cycA (Δc4), cycB (Δc5), and ccoP (ccoP-C368A), we demonstrate that cytochrome c2 is required for electron transfer from cytochrome c4 via the third heme group of CcoP to the nitrite reductase, AniA, and that cytochrome c5 transfers electrons to nitrite reductase by an independent pathway. We propose that cytochrome c2 forms a complex with cytochrome oxidase. If so, the redox state of cytochrome c2 might regulate electron transfer to nitrite or oxygen. However, our data are more consistent with a mechanism in which cytochrome c2 and the CcoQ subunit of cytochrome oxidase form alternative complexes that preferentially catalyze nitrite and oxygen reduction, respectively. Comparison with the much simpler electron transfer pathway for nitrite reduction in the meningococcus provides fascinating insights into niche adaptation within the pathogenic neisseriae. PMID:23543713

  14. Autoselection of cytoplasmic yeast virus like elements encoding toxin/antitoxin systems involves a nuclear barrier for immunity gene expression.

    Directory of Open Access Journals (Sweden)

    Alene Kast

    2015-05-01

    Full Text Available Cytoplasmic virus like elements (VLEs from Kluyveromyces lactis (Kl, Pichia acaciae (Pa and Debaryomyces robertsiae (Dr are extremely A/T-rich (>75% and encode toxic anticodon nucleases (ACNases along with specific immunity proteins. Here we show that nuclear, not cytoplasmic expression of either immunity gene (PaORF4, KlORF3 or DrORF5 results in transcript fragmentation and is insufficient to establish immunity to the cognate ACNase. Since rapid amplification of 3' ends (RACE as well as linker ligation of immunity transcripts expressed in the nucleus revealed polyadenylation to occur along with fragmentation, ORF-internal poly(A site cleavage due to the high A/T content is likely to prevent functional expression of the immunity genes. Consistently, lowering the A/T content of PaORF4 to 55% and KlORF3 to 46% by gene synthesis entirely prevented transcript cleavage and permitted functional nuclear expression leading to full immunity against the respective ACNase toxin. Consistent with a specific adaptation of the immunity proteins to the cognate ACNases, cross-immunity to non-cognate ACNases is neither conferred by PaOrf4 nor KlOrf3. Thus, the high A/T content of cytoplasmic VLEs minimizes the potential of functional nuclear recruitment of VLE encoded genes, in particular those involved in autoselection of the VLEs via a toxin/antitoxin principle.

  15. Autoselection of cytoplasmic yeast virus like elements encoding toxin/antitoxin systems involves a nuclear barrier for immunity gene expression.

    Science.gov (United States)

    Kast, Alene; Voges, Raphael; Schroth, Michael; Schaffrath, Raffael; Klassen, Roland; Meinhardt, Friedhelm

    2015-05-01

    Cytoplasmic virus like elements (VLEs) from Kluyveromyces lactis (Kl), Pichia acaciae (Pa) and Debaryomyces robertsiae (Dr) are extremely A/T-rich (>75%) and encode toxic anticodon nucleases (ACNases) along with specific immunity proteins. Here we show that nuclear, not cytoplasmic expression of either immunity gene (PaORF4, KlORF3 or DrORF5) results in transcript fragmentation and is insufficient to establish immunity to the cognate ACNase. Since rapid amplification of 3' ends (RACE) as well as linker ligation of immunity transcripts expressed in the nucleus revealed polyadenylation to occur along with fragmentation, ORF-internal poly(A) site cleavage due to the high A/T content is likely to prevent functional expression of the immunity genes. Consistently, lowering the A/T content of PaORF4 to 55% and KlORF3 to 46% by gene synthesis entirely prevented transcript cleavage and permitted functional nuclear expression leading to full immunity against the respective ACNase toxin. Consistent with a specific adaptation of the immunity proteins to the cognate ACNases, cross-immunity to non-cognate ACNases is neither conferred by PaOrf4 nor KlOrf3. Thus, the high A/T content of cytoplasmic VLEs minimizes the potential of functional nuclear recruitment of VLE encoded genes, in particular those involved in autoselection of the VLEs via a toxin/antitoxin principle. PMID:25973601

  16. Rapid and Simple Method for Detecting the Toxin B Gene of Clostridium difficile in Stool Specimens by Loop-Mediated Isothermal Amplification

    OpenAIRE

    Kato, Haru; Yokoyama, Toshiyuki; Kato, Hideaki; Arakawa, Yoshichika

    2005-01-01

    We applied the loop-mediated isothermal amplification (LAMP) assay to the detection of the toxin B gene (tcdB) of Clostridium difficile for identification of toxin B (TcdB)-positive C. difficile strains and detection of tcdB in stool specimens. tcdB was detected in all toxin A (TcdA)-positive, TcdB-positive (A+B+) and TcdA-negative, TcdB-positive (A−B+) C. difficile strains but not from TcdA-negative, TcdB-negative strains. Of the 74 stool specimens examined, A+B+ or A−B+ C. difficile was rec...

  17. Black Box Chimera Check (B2C2): a Windows-Based Software for Batch Depletion of Chimeras from Bacterial 16S rRNA Gene Datasets.

    Science.gov (United States)

    Gontcharova, Viktoria; Youn, Eunseog; Wolcott, Randall D; Hollister, Emily B; Gentry, Terry J; Dowd, Scot E

    2010-01-01

    The existing chimera detection programs are not specifically designed for "next generation" sequence data. Technologies like Roche 454 FLX and Titanium have been adapted over the past years especially with the introduction of bacterial tag-encoded FLX/Titanium amplicon pyrosequencing methodologies to produce over one million 250-600 bp 16S rRNA gene reads that need to be depleted of chimeras prior to downstream analysis. Meeting the needs of basic scientists who are venturing into high-throughput microbial diversity studies such as those based upon pyrosequencing and specifically providing a solution for Windows users, the B2C2 software is designed to be able to accept files containing large multi-FASTA formatted sequences and screen for possible chimeras in a high throughput fashion. The graphical user interface (GUI) is also able to batch process multiple files. When compared to popular chimera screening software the B2C2 performed as well or better while dramatically decreasing the amount of time required generating and screening results. Even average computer users are able to interact with the Windows .Net GUI-based application and define the stringency to which the analysis should be done. B2C2 may be downloaded from http://www.researchandtesting.com/B2C2. PMID:21339894

  18. 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. PMID:26985584

  19. Use of the espZ Gene Encoded in the Locus of Enterocyte Effacement for Molecular Typing of Shiga Toxin-Producing Escherichia coli

    OpenAIRE

    Gilmour, Matthew W.; Tracz, Dobryan M.; Andrysiak, Ashleigh K.; Clark, Clifford G.; Tyson, Shari; Severini, Alberto; Ng, Lai-King

    2006-01-01

    Infections with Shiga toxin-producing Escherichia coli (STEC) result in frequent cases of sporadic and outbreak-associated enteric bacterial disease in humans. Classification of STEC is by stx genotype (encoding the Shiga toxins), O and H antigen serotype, and seropathotype (subgroupings based upon the clinical relevance and virulence-related genotypes of individual serotypes). The espZ gene is encoded in the locus of enterocyte effacement (LEE) pathogenicity island responsible for the attach...

  20. Multiplex PCR for the Rapid Simultaneous Speciation and Detection of Methicillin-Resistance and Genes Encoding Toxin Production in Staphylococcus aureus.

    Science.gov (United States)

    Jones, M E; Köhrer, K; Schmitz, F J

    2001-01-01

    The use of polymerase chain reaction (PCR) to rapidly amplify target DNA molecules has evolved a place within diagnostic microbiology allowing the sensitive and specific identification of microorganisms concurrent with the detection of specific genes involved in resistance or virulence. This is particularly helpful when dealing with problem pathogens such as Staphylococcus aureus, where the rapid diagnosis and detection of methicillin-resistance can assist in the fast implementation of appropriate treatment and infection control measures (1-4). In addition, the rapid assessment of toxin production can ascertain whether toxin-related symptoms need to be considered (5). The protocol described here enables the simultaneous differentiation between S. aureus (and coagulase negative staphylococci) from other eubacterial organisms. Concomitant with species identification this protocol allows for the detection of specific staphylococcal resistance genes, such as mecA, encoding methicillin resistance, or staphylococcal virulence genes, such as seb, sec1 and tst, encoding enterotoxin B, enterotoxin C, and toxic shock syndrome toxin-1, respectively. In S. aureus the detection of methicillin-resistance using agar diffusion or broth micro-dilution techniques, or toxin production using immunodiffusion, agglutination, or ELISA is often difficult. This is because the mecA gene and the genes involved in toxin production may be poorly expressed and influenced significantly by culture conditions (5-10). Other methods, in particular various hybridization techniques have been used as diagnostic tools. However. PMID:21374410

  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 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.

  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 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.

  3. 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.

  4. Comparison of real-time PCR for detection of the tcdC gene with four toxin immunoassays and culture in diagnosis of Clostridium difficile infection.

    Science.gov (United States)

    Sloan, Lynne M; Duresko, Brian J; Gustafson, Daniel R; Rosenblatt, Jon E

    2008-06-01

    We have developed a rapid real-time PCR method using fluorescence resonance energy transfer probes and the LightCycler (Roche Diagnostics), which will detect the presence of the tcdC gene of Clostridium difficile in stool samples. Our PCR method also will identify the presence of base pair deletions, one of which (18 bp) has been associated with the "epidemic" toxin-hyperproducing strains. We compared the results of this PCR with those of three C. difficile toxin-detecting enzyme immunoassays (EIAs), an EIA for the detection of glutamate dehydrogenase (GDH), and culture of C. difficile. A total of 200 stool specimens were studied by the methods under comparison. C. difficile was isolated from 49 specimens by culture, and 44 of these were confirmed as containing one of the genes associated with toxin production ("toxigenic culture"). Using toxigenic culture as the "gold standard", the sensitivities, specificities, and positive and negative predictive values, respectively, of the assays were 48%, 98%, 88%, and 87% for the Premier toxin A and B test; 48%, 99%, 91%, and 87% for the ImmunoCard toxin A & B test; 48%, 84%, 46%, and 85% for the Xpect C. difficile toxin A/B test; 32%, 100%, 100%, and 84% for the Triage C. difficile panel (for toxin A); and 86%, 97%, 90%, and 96% for the LightCycler PCR. Thus, in comparison to the sensitivity of toxigenic culture, the sensitivities of the toxin immunoassays were unacceptably low, while the LightCycler real-time PCR assay for the detection of the tcdC gene of C. difficile is sensitive and specific. PMID:18434563

  5. Escherichia coli harboring Shiga toxin 2 gene variants : frequency and association with clinical symptoms

    NARCIS (Netherlands)

    Friedrich, Alexander W; Bielaszewska, Martina; Zhang, Wen-Lan; Pulz, Matthias; Kuczius, Thorsten; Ammon, Andrea; Karch, Helge

    2002-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) from patients with hemolytic-uremic syndrome (HUS), patients with diarrhea without HUS, or asymptomatic subjects were genotyped to assess associations between stx2 variants and clinical manifestations of infection. Neither stx2d nor stx2e was found

  6. Phospholipase C Produced by Clostridium botulinum Types C and D:Comparison of Gene, Enzymatic, and Biological Activities with Those of Clostridium perfringens Alpha-toxin

    Directory of Open Access Journals (Sweden)

    Sakurai,Jun

    2013-02-01

    Full Text Available Clostridium botulinum type C and D strains recently have been found to produce PLC on egg yolk agar plates. To characterize the gene, enzymatic and biological activities of C. botulinum PLCs (Cb-PLCs, the cb-plc genes from 8 strains were sequenced, and 1 representative gene was cloned and expressed as a recombinant protein. The enzymatic and hemolytic activities of the recombinant Cb-PLC were measured and compared with those of the Clostridium perfringens alpha-toxin. Each of the eight cb-plc genes encoded a 399 amino acid residue protein preceded by a 27 residue signal peptide. The protein consists of 2 domains, the N- and C-domains, and the overall amino acid sequence identity between Cb-PLC and alpha-toxin was greater than 50%, suggesting that Cb-PLC is homologous to the alpha-toxin. The key residues in the N-domain were conserved, whereas those in the C-domain which are important in membrane interaction were different than in the alpha-toxin. As expected, Cb-PLC could hydrolyze egg yolk phospholipid, p-nitrophenylphosphorylcholine, and sphingomyelin, and also exhibited hemolytic activity;however, its activities were about 4- to over 200-fold lower than those of alpha-toxin. Although Cb-PLC showed weak enzymatic and biological activities, it is speculated that Cb-PLC might play a role in the pathogenicity of botulism or for bacterial survival.

  7. Neutralization of Bacterial YoeBSpn Toxicity and Enhanced Plant Growth in Arabidopsis thaliana via Co-Expression of the Toxin-Antitoxin Genes

    Science.gov (United States)

    Abu Bakar, Fauziah; Yeo, Chew Chieng; Harikrishna, Jennifer Ann

    2016-01-01

    Bacterial toxin-antitoxin (TA) systems have various cellular functions, including as part of the general stress response. The genome of the Gram-positive human pathogen Streptococcus pneumoniae harbors several putative TA systems, including yefM-yoeBSpn, which is one of four systems that had been demonstrated to be biologically functional. Overexpression of the yoeBSpn toxin gene resulted in cell stasis and eventually cell death in its native host, as well as in Escherichia coli. Our previous work showed that induced expression of a yoeBSpn toxin-Green Fluorescent Protein (GFP) fusion gene apparently triggered apoptosis and was lethal in the model plant, Arabidopsis thaliana. In this study, we investigated the effects of co-expression of the yefMSpn antitoxin and yoeBSpn toxin-GFP fusion in transgenic A. thaliana. When co-expressed in Arabidopsis, the YefMSpn antitoxin was found to neutralize the toxicity of YoeBSpn-GFP. Interestingly, the inducible expression of both yefMSpn antitoxin and yoeBSpn toxin-GFP fusion in transgenic hybrid Arabidopsis resulted in larger rosette leaves and taller plants with a higher number of inflorescence stems and increased silique production. To our knowledge, this is the first demonstration of a prokaryotic antitoxin neutralizing its cognate toxin in plant cells. PMID:27104531

  8. Activation of the ustilagic acid biosynthesis gene cluster in Ustilago maydis by the C2H2 zinc finger transcription factor Rua1.

    Science.gov (United States)

    Teichmann, Beate; Liu, Lidan; Schink, Kay Oliver; Bölker, Michael

    2010-04-01

    The phytopathogenic basidiomycetous fungus Ustilago maydis secretes, under conditions of nitrogen starvation, large amounts of the biosurfactant ustilagic acid (UA). This secreted cellobiose glycolipid is toxic for many microorganisms and confers biocontrol activity to U. maydis. Recently, a large gene cluster that is responsible for UA biosynthesis was identified. Here, we show that expression of all cluster genes depends on Rua1, a nuclear protein of the C(2)H(2) zinc finger family, whose gene is located within the gene cluster. While deletion of rua1 results in complete loss of UA production, overexpression of rua1 promotes increased UA synthesis even in the presence of a good nitrogen source. Bioinformatic analysis allowed us to identify a conserved sequence element that is present in the promoters of all structural genes involved in UA biosynthesis. Deletion analysis of several promoters within the cluster revealed that this DNA element serves as an upstream activating sequence (UAS) and mediates Rua1-dependent expression. We used the yeast one-hybrid system to demonstrate specific recognition of this DNA element by Rua1. Introduction of nucleotide exchanges into the consensus sequence interfered with Rua1-dependent activation, suggesting that this sequence element acts as a direct binding site for Rua1. PMID:20173069

  9. Cloning and characterization of a novel human zinc finger gene, hKid3, from a C2H2-ZNF enriched human embryonic cDNA library

    International Nuclear Information System (INIS)

    To investigate the zinc finger genes involved in human embryonic development, we constructed a C2H2-ZNF enriched human embryonic cDNA library, from which a novel human gene named hKid3 was identified. The hKid3 cDNA encodes a 554 amino acid protein with an amino-terminal KRAB domain and 11 carboxyl-terminal C2H2 zinc finger motifs. Northern blot analysis indicates that two hKid3 transcripts of 6 and 8.5 kb express in human fetal brain and kidney. The 6 kb transcript can also be detected in human adult brain, heart, and skeletal muscle while the 8.5 kb transcript appears to be embryo-specific. GFP-fused hKid3 protein is localized to nuclei and the ZF domain is necessary and sufficient for nuclear localization. To explore the DNA-binding specificity of hKid3, an oligonucleotide library was selected by GST fusion protein of hKid3 ZF domain, and the consensus core sequence 5'-CCAC-3' was evaluated by competitive electrophoretic mobility shift assay. Moreover, The KRAB domain of hKid3 exhibits transcription repressor activity when tested in GAL4 fusion protein assay. These results indicate that hKid3 may function as a transcription repressor with regulated expression pattern during human development of brain and kidney

  10. The midgut cadherin-like gene is not associated with resistance to Bacillus thuringiensis toxin Cry1Ac in Plutella xylostella (L.).

    Science.gov (United States)

    Guo, Zhaojiang; Kang, Shi; Zhu, Xun; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhang, Youjun

    2015-03-01

    The Gram-positive bacterium Bacillus thuringiensis (Bt) produces Cry toxins that have been used to control important agricultural pests. Evolution of resistance in target pests threatens the effectiveness of these toxins when used either in sprayed biopesticides or in Bt transgenic crops. Although alterations of the midgut cadherin-like receptor can lead to Bt Cry toxin resistance in many insects, whether the cadherin gene is involved in Cry1Ac resistance of Plutella xylostella (L.) remains unclear. Here, we present experimental evidence that resistance to Cry1Ac or Bt var. kurstaki (Btk) in P. xylostella is not due to alterations of the cadherin gene. The bona fide P. xylostella cadherin cDNA sequence was cloned and analyzed, and comparisons of the cadherin cDNA sequence among susceptible and resistant P. xylostella strains confirmed that Cry1Ac resistance was independent of mutations in this gene. In addition, real-time quantitative PCR (qPCR) indicated that cadherin transcript levels did not significantly differ among susceptible and resistant P. xylostella strains. RNA interference (RNAi)-mediated suppression of cadherin gene expression did not affect larval susceptibility to Cry1Ac toxin. Furthermore, genetic linkage assays using four cadherin gDNA allelic biomarkers confirmed that the cadherin gene is not linked to resistance against Cry1Ac in P. xylostella. Taken together, our findings demonstrate that Cry1Ac resistance of P. xylostella is independent of the cadherin gene. PMID:25595643

  11. 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; McClane, Bruce A

    2013-06-01

    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

  12. POLYMERASE CHAIN REACTION FOR THE DETECTION OF TOXIN A ( TCD A AND TOXIN B ( TCD B GENES OF CLOSTRIDIUM DIFFICILE ISOLATED FROM DIARRHOEAL CASES AND ANALYSIS OF THE CLINICAL SPECTRUM

    Directory of Open Access Journals (Sweden)

    Sherin

    2015-04-01

    Full Text Available BACKGROUND: Molecular methods for detection of toxigenic Clostridium difficile have been established in the developed countries though not very common in our country. AIMS: The study was intended to determine the presence of toxin A and toxin B genes of Clostridium difficile isolates by means of polymerase chain reaction (PCR and a nalysis of clinical picture of the patients. MATERIALS AND METHODS: The prospective study was conducted in a tertiary care teaching hospital, South India from January 2012 to December 2014. Stool samples were collected consecutively from 563 in patients with diarrhoea from various wards. Clostridium difficile was isolated and identified by semi quantitative culture, latex agglutination and biochemical reactions. These isolates were then subjected to PCR for the detection of toxin A and toxin B genes. In addition, enzyme immunoassay was performed on stool samples for the detection of toxins A and B. The clinical spectrum of PCR positive patients was also analyzed. RESULTS: From 563 stool specimens, 113 (20. 07% Clostridium difficile isolates wer e grown by culture and identified by latex agglutination and biochemical reactions. Out of 113 isolates, 94 were subjected to PCR. 50 (53. 19% isolates out of 94 were found to be positive. Three toxigenic types obtained were A + B + , A - B + and A + B - which accou nted for 6. 38%, 42.55% and 4. 26% respectively. A - B - isolates were 46. 81%. 30 (26.55% out of 113 stool samples (which were culture positive was also enzyme immunoassay positive. 32 (64% out of 50 PCR positive patients e xhibited antibiotic usage (p<0. 05 and 39 (78% revealed the presence of underl ying illnesses/conditions (p<0. 01. CONCLUSION: The study highlights the usefulness of PCR for detection of toxigenic Clostridium difficile and for determination of its molecular epidemiology.

  13. Homologs to Cry toxin receptor genes in a de novo transcriptome and their altered expression in resistant Spodoptera litura larvae.

    Science.gov (United States)

    Gong, Liang; Wang, Huidong; Qi, Jiangwei; Han, Lanzhi; Hu, Meiying; Jurat-Fuentes, Juan Luis

    2015-07-01

    Insect resistance threatens sustainability of insecticides based on Cry proteins from the bacterium Bacillus thuringiensis (Bt). Since high levels of resistance to Cry proteins involve alterations in Cry-binding midgut receptors, their identification is needed to develop resistance management strategies. Through Illumina sequencing we generated a transcriptome containing 16,161 annotated unigenes for the Oriental leafworm (Spodoptera litura). Transcriptome mining identified 6 contigs with identity to reported lepidopteran Cry toxin receptors. Using PCR we confirmed their expression during the larval stage and compared their quantitative expression in larvae from susceptible and a field-derived Cry1Ca resistant strain of S. litura. Among reduced transcript levels detected for most tested contigs in the Cry1Ca-resistant S. litura larvae, the most dramatic reduction (up to 99%) was detected for alkaline phosphatase contigs. This study significantly expands S. litura transcriptomic resources and provides preliminary identification of putative receptor genes with altered expression in S. litura resistant to Cry1Ca toxin. PMID:25981133

  14. Characterization of shiga toxin-producing Escherichia coli recovered from domestic animals to determine stx variants, virulence genes, and cytotoxicity in mammalian cells

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli (STEC) can cause foodborne illnesses ranging from diarrhea to severe diseases such as hemorrhagic colitis (HC), and hemolytic uremic syndrome (HUS) in humans. In this study, we determined virulence genes, stx subtypes and we evaluated the cytotoxicity in mammal...

  15. A rapid method for the discrimination of genes encoding classical Shiga toxin (Stx) 1 and its variants, Stx1c and Stx1d, in Escherichia coli

    NARCIS (Netherlands)

    Kuczius, Thorsten; Bielaszewska, Martina; Friedrich, Alexander W; Zhang, Wenlan

    2004-01-01

    Subtyping of Shiga toxin (Stx)-encoding genes by conventional polymerase chain reaction (PCR) is time-consuming. We developed a single step real-time fluorescence PCR with melting curve analysis to distinguish rapidly stx1 from its variants, stx1c and stx1d. Melting temperatures (Tm) of 206 Stx-prod

  16. Fusion of Clostridium perfringens type D and B epsilon and beta toxin genes and it’s cloning in E. coli

    Directory of Open Access Journals (Sweden)

    Goudarzi, H.,

    2011-06-01

    Full Text Available Designing and producing a proper fusion construction is the most important problem of producing large quantities of a properly folded functional protein. This construction should have all necessary components of a real gene. A good designed fusion gene construction could be cloned into a good and suitable host. Clostridium perfringens is an important pathogen of humans and livestock and produces numerous toxins including epsilon and beta which are responsible for severe diseases. In the present study a new construction containing Clostridium perfringens type D epsilon toxin gene and type B beta toxin gene was designed. At the first step two pairs of primers were used for these genes amplification. At the next step epsilon forward and beta reveres primers were used to produce a chimeric gene containing amplified partial cds of etxD and partial cds of cpbB which are linked together by the AEAAAKEAAAKA fragment as a small linker. The method was based on fusion PCR and using of Pfu DNA polymerase, which has a proofreading activity. The fusion gene inserted into pJET1.2blunt and cloned into E.coli strain TOP10. Based on the latest information, this is the first design and cloning of epsilon-beta fusion gene and also this is the first time that PCR fusion strategy is used for Clostriadial gene fusion, which could be used for development of a recombinant epsilon-beta fusion protein vaccine. This construction also could serve as a model for development and production of novel fusion protein for other potential proteins and toxins.

  17. Molecular epidemiology of Vibrio cholerae O1 isolated in Nepal by southern hybridization with a cholera toxin gene probe.

    Science.gov (United States)

    Yamamoto, K; Shrestha, J; Iida, T; Yoh, M; Honda, T

    1995-06-01

    A cholera epidemic broke out in 1992 due to Vibrio cholerae O1 biotype El Tor in the eastern and southern belt of Nepal mainly among the Bhutanese refugees. Restriction fragment profiles (RFP) of DNA fragments of V. cholerae O1 isolates hybridized with an enzyme-labelled oligonucleotide probe for cholera toxin gene (ctx) by Southern Hybridization were compared. The probe hybridized with the 13- and 8-kb fragments of PstI-digested total DNA in all isolates observed in the epidemic. This RFP in the Nepalese strain was not observed in the strains isolated during other epidemics but was observed in the strains isolated from the exported marine products from Taiwan and Thailand. PMID:7594311

  18. Prevalence of virulence genes and cytolethal distending toxin production in Campylobacter jejuni isolates from diarrheal patients in Bangladesh.

    Science.gov (United States)

    Talukder, Kaisar A; Aslam, Mohammad; Islam, Zhahirul; Azmi, Ishrat J; Dutta, Dilip K; Hossain, Sabir; Nur-E-Kamal, Alam; Nair, Gopinath B; Cravioto, Alejandro; Sack, David A; Endtz, Hubert P

    2008-04-01

    From 300 stool samples, 58 Campylobacter strains were isolated by standard microbiological and biochemical methods. Of these, 40 strains were identified as Campylobacter jejuni and 5 as Campylobacter coli. The presence of flaA (100%), cadF (100%), racR (100%), dnaJ (100%), pldA (100%), ciaB (95%), virB11 (0%), ceuE (82.5%), cdtA (97.5%), cdtB (97.5%), cdtC (97.5%), and wlaN (7.5%) genes was detected in C. jejuni by PCR. All C. jejuni strains but one produced cytolethal distending toxin in a HeLa cell assay. PMID:18287317

  19. Abundance in Sewage of Bacteriophages That Infect Escherichia coli O157:H7 and That Carry the Shiga Toxin 2 Gene

    OpenAIRE

    Muniesa, Maite; Jofre, Juan

    1998-01-01

    Shiga toxin-converting bacteriophages are involved in the pathogenicity of some enteric bacteria, such as Escherichia coli O157:H7, but data on the occurrence and distribution of such phages as free particles in nature were not available. An experimental approach has been developed to detect the presence of the Shiga toxin 2 (Stx 2)-encoding bacteriophages in sewage. The Stx 2 gene was amplified by PCR from phages concentrated from 10-ml samples of sewage. Moreover, the phages carrying the St...

  20. Hybridization of 2,659 Clostridium Perfringens Isolates with Gene Probes for Seven Toxins (Alpha, Beta, Epsilon, Iota, Theta, Mu, and Enterotoxin) and for Sialidase

    OpenAIRE

    Daube, Georges; Simon, Patricia; Limbourg, Bernard; Manteca, Christophe; Mainil, Jacques; Kaeckenbeeck, Albert

    1996-01-01

    OBJECTIVE--To genetically characterize Clostridium perfringens isolates for association of pathologic type with various diseases. DESIGN--Prospective study. SAMPLE POPULATION--2,659 C perfringens isolates from various nonhuman animals species, human beings, and foods. PROCEDURE--Colony hybridization with DNA probes for 7 toxin (alpha, beta, epsilon, iota (subunits a and b), theta, mu, and enterotoxin) genes and 1 sialidase gene were performed to group the isolates by pathologic type. RESULTS-...

  1. 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

  2. PolySearch2: a significantly improved text-mining system for discovering associations between human diseases, genes, drugs, metabolites, toxins and more

    OpenAIRE

    Liu, Yifeng; Liang, Yongjie; Wishart, David

    2015-01-01

    PolySearch2 (http://polysearch.ca) is an online text-mining system for identifying relationships between biomedical entities such as human diseases, genes, SNPs, proteins, drugs, metabolites, toxins, metabolic pathways, organs, tissues, subcellular organelles, positive health effects, negative health effects, drug actions, Gene Ontology terms, MeSH terms, ICD-10 medical codes, biological taxonomies and chemical taxonomies. PolySearch2 supports a generalized ‘Given X, find all associated Ys’ q...

  3. Identification of genes implicated in toxin production in the cyanobacterium Cylindrospermopsis raciborskii

    DEFF Research Database (Denmark)

    Schembri, Mark; Neilan, B.A.; Saint, C.P.

    2001-01-01

    strain-specific distribution of the PKS and PS genes in C. raciborskii isolates demonstrated a direct link between the presence of these two genes and the ability to produce cylindrospermopsin. Interestingly, the possession of these two genes was also linked. They were also identified in an Anabaena...

  4. Characterization of pathogenic Escherichia coli isolated from humans in Austria : phenotypes, toxin gene types and epidemiology

    NARCIS (Netherlands)

    Wagner, M; Allerberger, F; Manafi, M; Lindner, G; Friedrich, A W; Sonntag, A-K; Foissy, H

    2004-01-01

    One hundred and ten clinical Escherichia coli isolates of serovar O157 (n = 102) and O26 (n = 8) were characterized for the presence of putative virulence genes by PCR. All but one of these isolates contained the eae gene. The EHEC-hly gene could be detected in all E. coli O157 and in 50% of E. coli

  5. Two mutant alleles of the human cytochrome P-450dbl gene (P450C2D1) associated with genetically deficient metabolism of debrisoquine and other drugs

    International Nuclear Information System (INIS)

    The debrisoquine polymorphism is a clinically important genetic defect of drug metabolism affecting 5-10% of individuals in Caucasian populations. It is inherited as an autosomal recessive trait. A full-length cDNA for human cytochrome P-450db1, the deficient enzyme (also designated P450IID1 for P450 family II subfamily D isozyme 1), has recently been cloned. Leukocyte DNA from extensive metabolizers (EMs) or poor metabolizers (PMs) of debrisoquine was examined by Southern analysis. Two polymorphic restriction fragments were associated with the PM phenotype when DNAs from 24 unrelated PM and 29 unrelated EM individuals were probed with P-450db1 cDNA after digestion with Xba I restriction endonuclease and Southern blotting. Seventy-five percent of PMs had either the 44-kb or the 11.5-kb fragment or both. Segregation of these restriction fragment length polymorphisms in the families of six PM probands demonstrated that each of the two fragments is allelic with the 29-kb fragment present in all EM individuals and suggests that they identify two independent mutated alleles of the P-450db1 gene (designated P450C2D1). The Xba I 44-kb fragment and 11.5-kb fragment were in linkage disequilibrium with restriction fragment length polymorphisms generated by four and five additional restriction endonucleases, respectively, which can be used to identify the same mutant alleles for the P-450db1 gene

  6. Isolation and identification of a marine killer yeast strain YF07b and cloning of the gene encoding killer toxin from the yeast

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It was found that the marine yeast strain YF07b could secrete a large amount of killer toxin against a pathogenic yeast strain WCY which could cause milky disease in Portunus trituberculatus. The marine yeast strain YF07b was identified to be Pichia anomala according to the results of routine yeast identification and 18S rDNA and ITS sequences. The gene encoding killer toxin in the marine yeast strain YF07b was amplified by PCR technology. After sequencing, the results show that an open reading frame, consisting of 1 281 bp, encoded a presumed protein of 427 amino acids. The sequence of the cloned gene was found to have 99% match with that of the gene encoding killer toxin in Pichia anomalas strain K. A signal peptide including 17 amino acids appeared in the N-terminal domain of the killer toxin. Therefore, the mature protein consisted of 410 amino acids, its molecular mass was estimated to be 47.4 ku and its isoelctronic point was 4.5.

  7. 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

    Directory of Open Access Journals (Sweden)

    Fry Bryan G

    2007-09-01

    Full Text Available Abstract 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.

  8. 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.

  9. Characterization of Toxin Plasmids in Clostridium perfringens Type C Isolates▿

    OpenAIRE

    Gurjar, Abhijit; Li, Jihong; McClane, Bruce A.

    2010-01-01

    Clostridium perfringens type C isolates cause enteritis necroticans in humans or necrotizing enteritis and enterotoxemia in domestic animals. Type C isolates always produce alpha toxin and beta toxin but often produce additional toxins, e.g., beta2 toxin or enterotoxin. Since plasmid carriage of toxin-encoding genes has not been systematically investigated for type C isolates, the current study used Southern blot hybridization of pulsed-field gels to test whether several toxin genes are plasm...

  10. C2 Agility

    DEFF Research Database (Denmark)

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

    circumstances. SAS-085 was formed to improve the understanding of C2 Agility and assess its importance to NATO. SAS-085 accomplished these objectives by articulating the principles of C2 Agility, in the form of a C2 Agility Conceptual Model, substantially validating this model and establishing the importance of...

  11. Mutation of an aminopeptidase N gene is associated with Helicoverpa armigera resistance to Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Zhang, Shaoping; Cheng, Hongmei; Gao, Yulin; Wang, Guirong; Liang, Gemei; Wu, Kongming

    2009-07-01

    A Cry1Ac-resistant strain (Bt-R) of Helicoverpa armigera, with 2971-fold resistance, was derived by selection with Cry1Ac toxin for 75 generations. We used cDNA-amplified fragment length polymorphism analysis to identify those genes differentially expressed in the Cry1Ac-resistant and -susceptible strains, which revealed 212 differentially expressed transcripts among 2000 screened cDNAs. Among these transcript-derived fragments (TDFs), 37 showed some homology to known sequences, including Aminopeptidase N (APN), which is expressed in the midgut epithelium and has been implicated as a Cry1A subfamily receptor in several moths, including H. armigera. We confirmed the TDF by RT-PCR and identified a deletion mutation of apn1 in the Bt-R strain. We expressed the TDF in bacteria. The partial HaAPN1-96S wild-type protein, bound to Cry1Ac on ligand blots, whereas HaAPN1-BtR did not. This suggested that HaAPN1 is a receptor for Bt Cry1Ac and that its deletion mutation is associated with Cry1Ac resistance in H. armigera. The absence of one binding site is responsible for its resistance to Cry1Ac. We developed an allele-specific PCR to monitor whether the apn1 gene in an H. armigera field population produced a similar mutation. No deleted mutants were found in 2250 individuals collected from the field in 2006-2007. PMID:19376227

  12. Detection of five Shiga toxin-producing Escherichia coli genes with multiplex PCR.

    Science.gov (United States)

    Son, Insook; Binet, Rachel; Maounounen-Laasri, Anna; Lin, Andrew; Hammack, Thomas S; Kase, Julie A

    2014-06-01

    Escherichia coli serogroup O157 is the pathogen most commonly associated with foodborne disease outbreaks, but epidemiological studies suggest that non-O157 Shiga toxin-producing E. coli (STEC) is a major player as well. The ten most clinically relevant STECs belong to serogroups O26, O103, O111, O145, O157, O91, O113, O128, O45, and O121; but emerging strains, such as O104:H4 that was identified with the 2011 German outbreak, could become more prevalent in the future. A 75-min conventional multiplex PCR assay, IS-5P, targeting the four virulence factors stx1, stx2, eae, and ehxA plus the O157:H7-specific +93 uidA single nucleotide polymorphism was developed to better assess the potential pathogenicity of STEC isolates. All 212 STEC DNAs showed one to five amplification products, while the non-E. coli DNA did not react to this multiplex PCR assay. Enrichment broths obtained from baby spinach, alfalfa sprouts, and cilantro artificially inoculated with O26, O103, and O121 STECs reacted positively to the multiplex assay. Unlike the current FDA BAM 5P PCR, designed for the specific detection of O157:H7, IS-5P will identify potentially harmful O157:H7 and non-O157 STECs so they can be removed from the nation's food supply. PMID:24549195

  13. Campylobacter jejuni, Campylobacter coli, and cytolethal distending toxin (CDT) genes in common teals (Anas crecca)

    OpenAIRE

    Gargiulo, Antonio; Sensale, Mariangela; Marzocco, Laura; Fioretti, Alessandro; Menna, Lucia F.; Dipineto, Ludovico

    2011-01-01

    Abstarct To evaluate the presence of Campylobacter spp. and related cdt genes, cloacal swabs were collected from 70 common teals (Anas crecca) and analyzed by culture methods and polymerase chain reaction. In addition, C. jejuni were examined also for the presence of wlaN gene. This is believed to be the first report of Campylobacter spp. in common teal and our results confirm the very common occurrence of C. jejuni (n=40) and C. coli (n=13) in waterfowls. Furthermore, the cdt gene...

  14. Campylobacter jejuni, Campylobacter coli, and cytolethal distending toxin (CDT) genes in common teals (Anas crecca).

    Science.gov (United States)

    Gargiulo, Antonio; Sensale, Mariangela; Marzocco, Laura; Fioretti, Alessandro; Menna, Lucia F; Dipineto, Ludovico

    2011-06-01

    To evaluate the presence of Campylobacter spp. and related cdt genes, cloacal swabs were collected from 70 common teals (Anas crecca) and analyzed by culture methods and polymerase chain reaction. In addition, C. jejuni were examined also for the presence of wlaN gene. This is believed to be the first report of Campylobacter spp. in common teal and our results confirm the very common occurrence of C. jejuni (n=40) and C. coli (n=13) in waterfowls. Furthermore, the cdt genes were frequently present in both C. jejuni and C. coli isolated. Moreover, seven C. jejuni isolates carried also the wlaN gene which is presumably involved in the expression of ganglioside mimics in Guillain-Barré syndrome. PMID:21450419

  15. Comparative possession of Shiga toxin, intimin, enterohaemolysin and major extended spectrum beta lactamase (ESBL) genes in Escherichia coli isolated from backyard and farmed poultry

    OpenAIRE

    Samanta, I.; Joardar, S. N.; Das, P. K.; Sar, T. K.

    2015-01-01

    The present work was conducted to compare the occurrence of Escherichia coli possessing virulence and ESBL genes in backyard and farmed poultry. Three hundred and sixty samples from the poultry kept in backyard system and 120 samples from the farmed birds were collected from West Bengal, India. Among the E. coli isolates of backyard poultry (O2, O10, O25, O55, O60, O106, UT), none of them possessed any of the Shiga toxin genes and eight E. coli isolates (8/272; 2.9%) harboured eaeA gene alone...

  16. Molecular Characterization of Clostridium perfringens Isolates from Humans with Sporadic Diarrhea: Evidence for Transcriptional Regulation of the Beta2-Toxin-Encoding Gene

    OpenAIRE

    Harrison, Ben; Raju, Deepa; Garmory, Helen S.; Brett, Moira M.; Titball, Richard W.; Sarker, Mahfuzur R.

    2005-01-01

    Clostridium perfringens type A food poisoning is caused by C. perfringens isolates carrying a chromosomal enterotoxin gene (cpe), while non-food-borne gastrointestinal (GI) diseases, such as antibiotic-associated diarrhea (AAD) and sporadic diarrhea (SD), are caused by C. perfringens plasmid cpe isolates. A recent study reported the association of beta2 toxin (CPB2) with human GI diseases, and particularly AAD/SD, by demonstrating that a large percentage of AAD/SD isolates, in contrast to a s...

  17. 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.

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

    Science.gov (United States)

    Reis, Andre L S; Montanhini, Maike T M; Bittencourt, Juliana V M; Destro, Maria T; Bersot, Luciano S

    2013-12-01

    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. PMID:24688511

  19. Paralytic Toxins Accumulation and Tissue Expression of α-Amylase and Lipase Genes in the Pacific Oyster Crassostrea gigas Fed with the Neurotoxic Dinoflagellate Alexandrium catenella

    Directory of Open Access Journals (Sweden)

    Mohamed Laabir

    2012-11-01

    Full Text Available The pacific oyster Crassostrea gigas was experimentally exposed to the neurotoxic Alexandrium catenella and a non-producer of PSTs, Alexandrium tamarense (control algae, at concentrations corresponding to those observed during the blooming period. At fixed time intervals, from 0 to 48 h, we determined the clearance rate, the total filtered cells, the composition of the fecal ribbons, the profile of the PSP toxins and the variation of the expression of two α-amylase and triacylglecerol lipase precursor (TLP genes through semi-quantitative RT-PCR. The results showed a significant decrease of the clearance rate of C. gigas fed with both Alexandrium species. However, from 29 to 48 h, the clearance rate and cell filtration activity increased only in oysters fed with A. tamarense. The toxin concentrations in the digestive gland rose above the sanitary threshold in less than 48 h of exposure and GTX6, a compound absent in A. catenella cells, accumulated. The α-amylase B gene expression level increased significantly in the time interval from 6 to 48 h in the digestive gland of oysters fed with A. tamarense, whereas the TLP gene transcript was significantly up-regulated in the digestive gland of oysters fed with the neurotoxic A. catenella. All together, these results suggest that the digestion capacity could be affected by PSP toxins.

  20. Cryptanalysis of C2

    DEFF Research Database (Denmark)

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

    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 56...... 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....

  1. 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 56...... 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....

  2. 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 ha...

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

    OpenAIRE

    Neilan Brett A; Kellmann Ralf; Mihali Troco K

    2009-01-01

    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 ...

  4. Control of anthocyanin biosynthesis pathway gene expression by eutypine, a toxin from Eutypa lata, in grape cell tissue cultures

    OpenAIRE

    Afifi, Maha; El-Kereamy, Ashraf; Legrand, Valérie; Chervin, Christian; Monje, Marie-Carmen; Nepveu, Françoise; Roustan, Jean-Paul

    2003-01-01

    Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzaldehyde, is a toxin produced by Eutypa lata, the causal agent of Eutypa dieback in grapevine. The effect of the toxin on anthocyanin synthesis has been investigated in Vitis vinifera cv. Gamay cell cultures. At concentrations higher than 200 μmol/L, eutypine reduced anthocyanin accumulation in cells. The reduction in anthocyanin accumulation was proportional to the eutypine concentrations and HPLC analysis showed that eutypine ...

  5. A new pyrosequencing assay for rapid detection and genotyping of Shiga toxin, intimin and O157-specific rfbE genes of Escherichia coli.

    Science.gov (United States)

    Goji, Noriko; Mathews, Amit; Huszczynski, George; Laing, Chad R; Gannon, Victor P J; Graham, Morag R; Amoako, Kingsley K

    2015-02-01

    Shiga toxin (stx)-producing Escherichia coli (STEC) contamination in food and water is one of the most recognized concerns and a major financial burden in human hygiene control worldwide. Rapid and highly reliable methods of detecting and identifying STEC causing gastroenteric illnesses are crucial to prevent foodborne outbreaks. A number of tests have been developed and commercialized to detect STEC using molecular microbiology techniques. Most of these are designed to identify virulence factors such as Shiga toxin and intimin as well as E. coli O and H antigen serotype specific genes. In order to screen pathogenic STEC without relying on O:H serotyping, we developed a rapid detection and genotyping assay for STEC virulence genes using a PCR-pyrosequencing application. We adapted the PyroMark Q24 Pyrosequencing platform for subtyping 4 major virulence genes, Shiga toxin 1 and 2 (stx1 and stx2), intimin (eae) and O157-antigen gene cluster target rfbE, using Single Nucleotide Polymorphism (SNP) analysis. A total of 224 E. coli strains including isolates from Canadian environment, food and clinical cases were examined. Based on the multiple alignment analysis of 30-80 base nucleotide pyrogram reads, three alleles of the Shiga toxin 1a gene (stx1a) (stx1a-I, stx1a-II, stx1a-III) were identified. Results of the stx1, stx2, eae and rfbE genotyping revealed that each group of O:H serotype shares distinctive characteristics that could be associated with the virulence of each genotype. O157:H7/NM carries stx1a-II (94%), stx2a (82%), λ/γ1-eae (100%) and rfbE type-H7/NM (100%). Whereas isolates of the "Top-6" serotypes (O26, O45, O103, O111, O121, O145) had a high incidence of stx1a-I (90%) and stx2a (100%). stx1a-III (60%) was only observed in non Top-7 (Top-6 plus O157) STEC and Shigella spp. The entire assay, from extracting DNA from colonies on a plate to the generation of sequence information, can be completed in 5h. The method of profiling these 4 STEC pathogenic

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

    Science.gov (United States)

    Chu, Weiwei; Wei, Wei; Yu, Shigang; Han, Haiyin; Shi, Xiaoli; Sun, Wenxing; Gao, Ying; Zhang, Lifan; Chen, Jie

    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. PMID:26896766

  7. TNF-α and IFN-s-Dependent Muscle Decay Is Linked to NF-κB- and STAT-1α-Stimulated Atrogin1 and MuRF1 Genes in C2C12 Myotubes

    Directory of Open Access Journals (Sweden)

    Barbara Pijet

    2013-01-01

    Full Text Available TNF-α was shown to stimulate mitogenicity in C2C12 myoblasts. Selected cytokines TNF-α, IFNα, or IFNγ reduced the expression of myosin heavy chain (MyHC IIa when given together. Molecular mechanisms of cytokine activities were controlled by NF-κB and JAK/STAT signaling pathways, as metabolic inhibitors, curcumin and AG490, inhibited some of TNF-α and IFNα/IFNγ effects. Insulin was hardly antagonistic to TNF-α- and IFNα/IFNγ-dependent decrease in MyHC IIa protein expression. Cytokines used individually or together also repressed myogenesis of C2C12 cells. Moreover, TNF-α- and IFNα/IFNγ-dependent effects on C2C12 myotubes were associated with increased activity of Atrogin1 and MuRF1 genes, which code ubiquitin ligases. MyHC IIa gene activity was unaltered by cytokines. Inhibition of NF-κB or JAK/STAT with specific metabolic inhibitors decreased activity of Atrogin1 and MuRF1 but not MyHC IIa gene. Overall, these results suggest cooperation between cytokines in the reduction of MyHC IIa protein expression level via NF-κB/JAK/STAT signaling pathways and activation of Atrogin1 and MuRF1 genes as their molecular targets. Insulin cotreatment or pretreatment does not protect against muscle decay induced by examined proinflammatory cytokines.

  8. Comparative analysis of BI/NAP1/027 hypervirulent strains reveals novel toxin B-encoding gene (tcdB) sequences.

    Science.gov (United States)

    Stabler, Richard A; Dawson, Lisa F; Phua, Leslie T H; Wren, Brendan W

    2008-06-01

    The reported incidence and mortality of Clostridium difficile-associated disease has increased significantly, which in part is likely to be due to the emergence of a new, highly virulent strain in North America and Europe. This epidemic strain, referred to as BI/NAP1/027, has increased virulence, attributed to overexpression of the two toxin-encoding genes, tcdA and tcdB, which may be due to truncation of the negative regulator (tcdC) by a 1 bp deletion. In a previous study of whole-genome comparisons using microarray analysis of 75 C. difficile isolates, it was noted that the 20,027 strains, which formed a hypervirulent clade, possessed a unique hybridization pattern for the 7 toxin B microarray reporters. This unique pattern was conserved in all of these 027 strains. The pattern was different for the 55 non-027 strains tested. These data, along with the knowledge that 027 strains are toxinotype III (i.e. possess a complete tcdB gene of comparable size to toxin reference strain VPI 10463), suggest that the sequence of the N-terminal binding domain of toxin B must be divergent from C. difficile strain 630 (and the other 55 strains tested). Additionally, these 027 strains had comparable hybridization patterns across the whole microarray, as well as for tcdB. Therefore, it was suggested that they share a similar, novel N-terminal binding domain. The aim of this study was to ascertain the sequence variation in tcdB from eight characterized BI/NAP1/027 strains. The study confirmed significant sequence variation of tcdB from the sequenced strain 630 and slight variation in tcdB among the eight 027 strains. These results suggest that toxin B from 027 strains may have a different binding capacity compared with its less-virulent counterparts and may, in addition to the mutated tcdC regulator, be responsible for the increased virulence of 027 strains. PMID:18480336

  9. siRNA表达载体对大鼠心肌H9c2细胞牛磺酸合成限速酶—CSD基因表达的抑制作用%THE INHIBITORY EFFECTS OF siRNA EXPRESSION VECTOR ON THE TAURINE BIOSYNTHETIC RATE-LIMITING ENZYME-CSD GENE OF RAT H9C2 CARDIAC MYOBLASTS

    Institute of Scientific and Technical Information of China (English)

    杨群辉; 杨硕; 冯颖; 吕秋凤; 杨建成; 胡建民

    2012-01-01

    Objective To investigate the inhibitory effects of RNAi (RNA interference) on CSD expression in rat H9c2 cells. Methods Four siRNAs expression vectors and one negative control siRNA expression vector were constructed to be targeted directly at cysteine sulfinate deacrboxylase (CSD) gene (Biomics Biotechonolgies, China). Then the recombinant plasmids siRNA1# siRNA2#, siRNA3#, siRNA4# and siRNA-Neg were transfected into H9c2 cells with liposomes Lipofectamine 2000. After transfection, the transfection efficiency was observed under fluorescent microscopy. CSD mRNA and protein expression were examined using RT-PCR and Western blot. MTT assay was performed to detect the state of cell proliferation. Results The transfection efficiency was about 70%. Recombinant plasmid siRNA 1# significantly decreased the expression of CSD at gene and protein levels (P0.05). Cell proliferation in the transfected cells was inhibited obviously by siRNAl# and siRNA2# plasmid compared with untransfected cells and negative control cells at 48 h, 72 h (P<0.05). Conclusion The siRNA 1# recombinant plasmid could effectively inhibit the expression of CSD in rat H9c2 cells and proliferation of H9c2 cells, which will benefit the further study on the function of CSD and taurine in cardiocytes metabolism.%目的 研究siRNA对大鼠心肌半胱亚磺酸脱羧酶(CSD)的抑制作用.方法 根据已克隆的大鼠心肌CSD基因序列(EU786150)设计并构建了4个siRNAs及1个阴性对照siRNA表达质粒,利用脂质体LipofectamineTM2000将构建好的重组质粒siRNA1#、siRNA2#、siRNA3#、siRNA4#及阴性对照质粒分别转染H9c2细胞,应用荧光显微镜观察转染效率、四唑盐(MTT)法检测H9c2细胞增殖情况、实时荧光定量PCR和Western-blot检测CSD mRNA和蛋白表达.结果 荧光显微镜观察细胞转染效率达70%左右;与阴性对照组、未转染组比较,siRNA1#重组质粒显著抑制了H9c2细胞中CSD mRNA和蛋白的表达(P< 0.05),而siRNA4#质粒

  10. Genetic relatedness of Clostridium difficile isolates from various origins determined by triple-locus sequence analysis based on toxin regulatory genes tcdC, tcdR, and cdtR.

    Science.gov (United States)

    Bouvet, Philippe J M; Popoff, Michel R

    2008-11-01

    A triple-locus nucleotide sequence analysis based on toxin regulatory genes tcdC, tcdR and cdtR was initiated to assess the sequence variability of these genes among Clostridium difficile isolates and to study the genetic relatedness between isolates. A preliminary investigation of the variability of the tcdC gene was done with 57 clinical and veterinary isolates. Twenty-three isolates representing nine main clusters were selected for tcdC, tcdR, and cdtR analysis. The numbers of alleles found for tcdC, tcdR and cdtR were nine, six, and five, respectively. All strains possessed the cdtR gene except toxin A-negative toxin B-positive variants. All but one binary toxin CDT-positive isolate harbored a deletion (>1 bp) in the tcdC gene. The combined analyses of the three genes allowed us to distinguish five lineages correlated with the different types of deletion in tcdC, i.e., 18 bp (associated or not with a deletion at position 117), 36 bp, 39 bp, and 54 bp, and with the wild-type tcdC (no deletion). The tcdR and tcdC genes, though located within the same pathogenicity locus, were found to have evolved separately. Coevolution of the three genes was noted only with strains harboring a 39-bp or a 54-bp deletion in tcdC that formed two homogeneous, separate divergent clusters. Our study supported the existence of the known clones (PCR ribotype 027 isolates and toxin A-negative toxin B-positive C. difficile variants) and evidence for clonality of isolates with a 39-bp deletion (toxinotype V, PCR ribotype 078) that are frequently isolated worldwide from human infections and from food animals. PMID:18832125

  11. MAPK signaling pathway alters expression of midgut ALP and ABCC genes and causes resistance to Bacillus thuringiensis Cry1Ac toxin in diamondback moth.

    Directory of Open Access Journals (Sweden)

    Zhaojiang Guo

    2015-04-01

    Full Text Available Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led to field-evolved resistance in several lepidopteran pests. Resistance to Bt Cry1Ac toxin in the diamondback moth, Plutella xylostella (L., was previously mapped to a multigenic resistance locus (BtR-1. Here, we assembled the 3.15 Mb BtR-1 locus and found high-level resistance to Cry1Ac and Bt biopesticide in four independent P. xylostella strains were all associated with differential expression of a midgut membrane-bound alkaline phosphatase (ALP outside this locus and a suite of ATP-binding cassette transporter subfamily C (ABCC genes inside this locus. The interplay between these resistance genes is controlled by a previously uncharacterized trans-regulatory mechanism via the mitogen-activated protein kinase (MAPK signaling pathway. Molecular, biochemical, and functional analyses have established ALP as a functional Cry1Ac receptor. Phenotypic association experiments revealed that the recessive Cry1Ac resistance was tightly linked to down-regulation of ALP, ABCC2 and ABCC3, whereas it was not linked to up-regulation of ABCC1. Silencing of ABCC2 and ABCC3 in susceptible larvae reduced their susceptibility to Cry1Ac but did not affect the expression of ALP, whereas suppression of MAP4K4, a constitutively transcriptionally-activated MAPK upstream gene within the BtR-1 locus, led to a transient recovery of gene expression thereby restoring the susceptibility in resistant larvae. These results highlight a crucial role for ALP and ABCC genes in field-evolved resistance to Cry1Ac and reveal a novel trans-regulatory signaling mechanism responsible for modulating the expression of these pivotal genes in P. xylostella.

  12. MAPK signaling pathway alters expression of midgut ALP and ABCC genes and causes resistance to Bacillus thuringiensis Cry1Ac toxin in diamondback moth.

    Science.gov (United States)

    Guo, Zhaojiang; Kang, Shi; Chen, Defeng; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhu, Xun; Baxter, Simon W; Zhou, Xuguo; Jurat-Fuentes, Juan Luis; Zhang, Youjun

    2015-04-01

    Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt) are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led to field-evolved resistance in several lepidopteran pests. Resistance to Bt Cry1Ac toxin in the diamondback moth, Plutella xylostella (L.), was previously mapped to a multigenic resistance locus (BtR-1). Here, we assembled the 3.15 Mb BtR-1 locus and found high-level resistance to Cry1Ac and Bt biopesticide in four independent P. xylostella strains were all associated with differential expression of a midgut membrane-bound alkaline phosphatase (ALP) outside this locus and a suite of ATP-binding cassette transporter subfamily C (ABCC) genes inside this locus. The interplay between these resistance genes is controlled by a previously uncharacterized trans-regulatory mechanism via the mitogen-activated protein kinase (MAPK) signaling pathway. Molecular, biochemical, and functional analyses have established ALP as a functional Cry1Ac receptor. Phenotypic association experiments revealed that the recessive Cry1Ac resistance was tightly linked to down-regulation of ALP, ABCC2 and ABCC3, whereas it was not linked to up-regulation of ABCC1. Silencing of ABCC2 and ABCC3 in susceptible larvae reduced their susceptibility to Cry1Ac but did not affect the expression of ALP, whereas suppression of MAP4K4, a constitutively transcriptionally-activated MAPK upstream gene within the BtR-1 locus, led to a transient recovery of gene expression thereby restoring the susceptibility in resistant larvae. These results highlight a crucial role for ALP and ABCC genes in field-evolved resistance to Cry1Ac and reveal a novel trans-regulatory signaling mechanism responsible for modulating the expression of these pivotal genes in P. xylostella. PMID:25875245

  13. Photorhabdus insect-related (Pir) toxin-like genes in a plasmid of Vibrio parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (AHPND) of shrimp.

    Science.gov (United States)

    Han, Jee Eun; Tang, Kathy F J; Tran, Loc H; Lightner, Donald V

    2015-02-10

    The 69 kb plasmid pVPA3-1 was identified in Vibrio parahaemolyticus strain 13‑028/A3 that can cause acute hepatopancreatic necrosis disease (AHPND). This disease is responsible for mass mortalities in farmed penaeid shrimp and is referred to as early mortality syndrome (EMS). The plasmid has a GC content of 45.9% with a copy number of 37 per bacterial cell as determined by comparative quantitative PCR analyses. It consists of 92 open reading frames that encode mobilization proteins, replication enzymes, transposases, virulence-associated proteins, and proteins similar to Photorhabdus insect-related (Pir) toxins. In V. parahaemolyticus, these Pir toxin-like proteins are encoded by 2 genes (pirA- and pirB-like) located within a 3.5 kb fragment flanked with inverted repeats of a transposase-coding sequence (1 kb). The GC content of these 2 genes is only 38.2%, substantially lower than that of the rest of the plasmid, which suggests that these genes were recently acquired. Based on a proteomic analysis, the pirA-like (336 bp) and pirB-like (1317 bp) genes encode for 13 and 50 kDa proteins, respectively. In laboratory cultures of V. parahaemolyticus 13-028/A3, both proteins were secreted into the culture medium. We developed a duplex PCR diagnostic method, with a detection limit of 10(5) CFU ml(-1) and targeting pirA- and pirB-like genes in this strain of V. parahaemolyticus. This PCR protocol can reliably detect AHPND-causing strains of V. parahaemolyticus and does not cross react with non-pathogenic strains or with other species of Vibrio isolated from shrimp ponds. PMID:25667334

  14. 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. PMID:24768765

  15. Safety assessment of the Clostridium butyricum MIYAIRI 588® probiotic strain including evaluation of antimicrobial sensitivity and presence of Clostridium toxin genes in vitro and teratogenicity in vivo.

    Science.gov (United States)

    Isa, K; Oka, K; Beauchamp, N; Sato, M; Wada, K; Ohtani, K; Nakanishi, S; McCartney, E; Tanaka, M; Shimizu, T; Kamiya, S; Kruger, C; Takahashi, M

    2016-08-01

    Probiotics are live microorganisms ingested for the purpose of conferring a health benefit on the host. Development of new probiotics includes the need for safety evaluations that should consider factors such as pathogenicity, infectivity, virulence factors, toxicity, and metabolic activity. Clostridium butyricum MIYAIRI 588(®) (CBM 588(®)), an anaerobic spore-forming bacterium, has been developed as a probiotic for use by humans and food animals. Safety studies of this probiotic strain have been conducted and include assessment of antimicrobial sensitivity, documentation of the lack of Clostridium toxin genes, and evaluation of CBM 588(®) on reproductive and developmental toxicity in a rodent model. With the exception of aminoglycosides, to which anaerobes are intrinsically resistant, CBM 588(®) showed sensitivity to all antibiotic classes important in human and animal therapeutics. In addition, analysis of the CBM 588(®) genome established the absence of genes for encoding for α, β, or ε toxins and botulin neurotoxins types A, B, E, or F. There were no deleterious reproductive and developmental effects observed in mice associated with the administration of CBM 588(®) These data provide further support for the safety of CBM 588(®) for use as a probiotic in animals and humans. PMID:26437792

  16. 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.

  17. Characterisation of IncA/C2 plasmids carrying an In416-like integron with the blaVIM-19 gene from Klebsiella pneumoniae ST383 of Greek origin.

    Science.gov (United States)

    Papagiannitsis, Costas C; Dolejska, Monika; Izdebski, Radosław; Giakkoupi, Panagiota; Skálová, Anna; Chudějová, Kateřina; Dobiasova, Hana; Vatopoulos, Alkiviadis C; Derde, Lennie P G; Bonten, Marc J M; Gniadkowski, Marek; Hrabák, Jaroslav

    2016-02-01

    The complete nucleotide sequences of three multidrug resistance (MDR) IncA/C-like plasmids from Enterobacteriaceae isolates carrying the VIM-type carbapenemase-encoding integrons In4863 (blaVIM-19-aacA7-dfrA1-ΔaadA1-smr2) or In4873 (blaVIM-1-aacA7-dfrA1-ΔaadA1-smr2) were determined, which are the first In416-like elements identified in Greece. Plasmids pKP-Gr642 and pKP-Gr8143 were from Klebsiella pneumoniae ST383 isolates, whereas plasmid pEcl-Gr4873 was from an Enterobacter cloacae ST88 isolate. Sequencing showed that pKP-Gr642 (162787bp) and pKP-Gr8143 (154395bp) consisted of the type 1 IncA/C2 conserved backbone, the blaCMY-2-like gene-containing region, and the ARI-B (with the sul2 gene) and ARI-A (with a class 1 integron) resistance islands, like the plasmid pUMNK88_161 from the USA. The third plasmid, pEcl-Gr4873 (153958bp), exhibited extensive similarity with the type 2 IncA/C2 plasmid pR55 from France. pEcl-Gr4873 carried only one resistance island of a hybrid transposon structure inserted in a different location to ARI-A in type 1 A/C2 plasmids. In all three plasmids, the In416-like integrons In4863 or In4873 were identified within non-identical class II transposon structures. All three In416-like-carrying regions presented significant similarities with the MDR region of the IncA/C2 plasmid pCC416 from Italy, carrying the prototype In416 integron (blaVIM-4-aacA7-dfrA1-ΔaadA1-smr2). These findings provided the basis for speculations regarding the evolution of IncA/C2 plasmids with In416-like integrons, and confirmed the rapid evolution of some IncA/C2 plasmid lineages. Considering the broad host range of IncA/C2 molecules, it seems that pKP-Gr642, pKP-Gr8143 and pEcl-Gr4873 plasmids might support the diffusion of In416-like integrons among Enterobacteriaceae. PMID:26795022

  18. Identification of the newly identified subtilase cytotoxin-encoding gene (subAB2-2) among clinical Shiga toxin-producing Escherichia coli isolates.

    Science.gov (United States)

    Son, Hoang Minh; Duc, Hoang Minh; Honjoh, Ken-Ichi; Miyamoto, Takahisa

    2015-12-01

    Subtilase cytotoxin (SubAB) is an important virulence factor of eae-negative Shiga toxin-producing Escherichia coli (STEC). Three variants of SubAB-encoding genes have been reported in the literature; however, the newly described subAB variant (subAB2-2) was found only in STEC strains from deer meat, sheep, and some wild animals. In this study, subAB variants were detected by PCR and DNA sequencing in 5 out of 12 (41.6%) eae-negative STEC strains isolated from patients. Most subAB-positive STEC strains (80%) harbored the subAB1 gene. The subAB2-2 gene was detected for the first time in the clinical STEC O128:H2 strain. Other virulence genes including stx1a, stx1c, stx2b, ehxA, and tia were also detected in this strain. The DNA sequence analyses of the subAB1 and subAB2-2 genes of the clinical STEC strains showed 99% and 100% identity to those of the reference strains 98NK2 and LM27558stx2, respectively. This is the first report on the detection of the subAB2-2 gene in a clinical STEC isolate. PMID:26588258

  19. Preliminary study on the isolation of Clostridium butyricum strains from natural sources in the UK and screening the isolates for presence of the type E botulinal toxin gene.

    Science.gov (United States)

    Ghoddusi, Hamid B; Sherburn, Richard

    2010-08-15

    Clostridia such as Clostridium tyrobutyricum, C. pasteurianum and C. butyricum may cause spoilage problems in certain types of food, but they are not normally regarded as dangerous. However some strains of C. butyricum have acquired the type E botulinum neurotoxin gene and have caused both infant and classical botulism in Italy (1986), China (1994) and India (1996). This study was carried out to examine a range of samples from fresh vegetables to food and environmental samples in the UK and test their ability to produce type E botulinal neurotoxin (BoNT) by probing for the presence of the toxin gene. Samples were enriched in modified Bhat and Barker (MBB) broth which is a minimal medium with lactate and acetate as a source of carbon and energy. In addition selective antibiotics are present in the medium to favour the growth of C. butyricum. This was followed by plating out onto iron sulphite agar (ISA) for isolation of C. butyricum from food and environmental samples. A total of 978 samples were tested and 302 (31%) yielded presumptive C. butyricum isolates. The highest percentage of positives came from soil, potato skins, Swede skin, yoghurt and cream. No positive isolates were obtained from pate, garlic or spring greens. A sub-sample of isolates was examined for the presence of gene encoding the type E botulinum neurotoxin using PCR. Only one of the many existing PCR methods was successful and therefore used for screening C. butyricum isolates for the presence of the type E toxin gene. None of the 93 tested isolates were found to be toxigenic (type E botulinal neurotoxin). PMID:20633941

  20. 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.

  1. Rapid and simple method for detecting the toxin B gene of Clostridium difficile in stool specimens by loop-mediated isothermal amplification.

    Science.gov (United States)

    Kato, Haru; Yokoyama, Toshiyuki; Kato, Hideaki; Arakawa, Yoshichika

    2005-12-01

    We applied the loop-mediated isothermal amplification (LAMP) assay to the detection of the toxin B gene (tcdB) of Clostridium difficile for identification of toxin B (TcdB)-positive C. difficile strains and detection of tcdB in stool specimens. tcdB was detected in all toxin A (TcdA)-positive, TcdB-positive (A(+)B(+)) and TcdA-negative, TcdB-positive (A(-)B(+)) C. difficile strains but not from TcdA-negative, TcdB-negative strains. Of the 74 stool specimens examined, A(+)B(+) or A(-)B(+) C. difficile was recovered from 39 specimens, of which 38 specimens were LAMP positive and one was negative. Amplification was obtained in 10 specimens that were culture negative, indicating that LAMP is highly sensitive. The LAMP assay was applied to detection of tcdB in DNA extracted by a simple boiling method from 47 of those 74 specimens, which were cultured overnight in cooked-meat medium (CMM). Twenty-two of 24 culture-positive specimens were positive for LAMP on DNA from the culture in CMM. Four specimens were culture negative but positive by LAMP on DNA from CMM cultures. The LAMP assay is a reliable tool for identification of TcdB-positive C. difficile as well as for direct detection of tcdB in stool specimens with high sensitivity. Detection of tcdB by LAMP from overnight cultures in CMM could be an alternative method of diagnostic testing at clinical laboratories without special apparatus. PMID:16333105

  2. Detection of Shiga Toxin-Producing Escherichia coli in Ground Beef Using the GeneDisc Real-Time PCR System

    Directory of Open Access Journals (Sweden)

    Pina eFratamico

    2012-12-01

    Full Text Available Escherichia coli O157:H7 and certain non-O157 Shiga toxin-producing Escherichia coli (STEC serogroups have emerged as important public health threats. The development of methods for rapid and reliable detection of this heterogeneous group of pathogens has been challenging. GeneDisc real-time PCR assays were evaluated for detection of the stx1, stx2, eae, and ehx genes and a gene that identifies the O157 serogroup followed by a second GeneDisc assay targeting serogroup-specific genes of STEC O26, O45, O91, O103, O111, O113, O121, O145, and O157. The ability to detect the STEC serogroups in ground beef samples artificially inoculated at a level of ca. 2-20 CFU/25 g and subjected to enrichment in mTSB or BPW was similar. Following enrichment, all inoculated ground beef samples showed amplification of the correct set of target genes carried by each strain. Samples inoculated with STEC serogroups O26, O45, O103, O111, O121, O145, and O157 were subjected to immunomagnetic separation, and isolation was achieved by plating onto Rainbow agar O157. Colonies were confirmed by PCR assays targeting stx1, stx2, eae, and serogroup-specific genes. Thus, this work demonstrated that GeneDisc assays are rapid, sensitive, and reliable and can be used for screening ground beef and potentially other foods for STEC serogroups that are important food-borne pathogens worldwide.

  3. Diagnosis of Clostridium difficile: real-time PCR detection of toxin genes in faecal samples is more sensitive compared to toxigenic culture.

    Science.gov (United States)

    Jensen, M B F; Olsen, K E P; Nielsen, X C; Hoegh, A M; Dessau, R B; Atlung, T; Engberg, J

    2015-04-01

    The diagnosis of Clostridium difficile infection (CDI) requires the detection of toxigenic C. difficile or its toxins and a clinical assessment. We evaluated the performance of four nucleic acid amplification tests (NAATs) detecting toxigenic C. difficile directly from faeces compared to routine toxigenic culture. In total, 300 faecal samples from Danish hospitalised patients with diarrhoea were included consecutively. Culture was performed in duplicate (routine and 'expanded toxigenic culture': prolonged and/or re-culture) and genotypic toxin profiling by polymerase chain reaction (PCR), PCR ribotyping and toxinotyping (TT) were performed on culture-positive samples. In parallel, the samples were analysed by four NAATs; two targeting tcdA or tcdB (illumigene C. difficile and PCRFast C. difficile A/B) and two multi-target real-time (RT) PCR assays also targeting cdt and tcdC alleles characteristic of epidemic and potentially more virulent PCR ribotypes 027, 066 and 078 (GeneXpert C. difficile/Epi and an 'in-house RT PCR' two-step algorithm). The multi-target assays were significantly more sensitive compared to routine toxigenic culture (p 95%), and in-house PCR displayed 100% correct identification of PCR ribotypes 066 and 078. Furthermore, the presence of the PCR enhancer bovine serum albumin (BSA) was found to be related to high sensitivity and low inhibition rate. Rapid laboratory diagnosis of toxigenic C. difficile by RT PCR was accurate. PMID:25421216

  4. HC toxin (a HDAC inhibitor) enhances IRS1-Akt signalling and metabolism in mouse myotubes.

    Science.gov (United States)

    Tan, Hayden Weng Siong; Sim, Arthur Yi Loong; Huang, Su Ling; Leng, Ying; Long, Yun Chau

    2015-12-01

    Exercise enhances numerous signalling pathways and activates substrate metabolism in skeletal muscle. Small molecule compounds that activate these cellular responses have been shown to recapitulate the metabolic benefits of exercise. In this study, a histone deacetylase (HDAC) inhibitor, HC toxin, was investigated as a small molecule compound that activates exercise-induced adaptations. In C2C12 myotubes, HC toxin treatment activated two exercise-stimulated pathways: AMP-activated protein kinase (AMPK) and Akt pathways. HC toxin increased the protein content and phosphorylation of insulin receptor substrate 1 as well as the activation of downstream Akt signalling. The effects of HC toxin on IRS1-Akt signalling were PI3K-dependent as wortmannin abolishes its effects on IRS1 protein accumulation and Akt phosphorylation. HC toxin-induced Akt activation was sufficient to enhance downstream mTOR complex 1 (mTORC1) signalling including p70S6K and S6, which were consistently abolished by PI3K inhibition. Insulin-stimulated glucose uptake, glycolysis, mitochondrial respiration and fatty acid oxidation were also enhanced in HC toxin-treated myotubes. When myotubes were challenged with serum starvation for the induction of atrophy, HC toxin treatment prevented the induction of genes that are involved in autophagy and proteasomal proteolysis. Conversely, IRS1-Akt signalling was not induced by HC toxin in several hepatoma cell lines, providing evidence for a favourable safety profile of this small molecule. These data highlight the potential of HDAC inhibitors as a novel class of small molecules for the induction of exercise-like signalling pathways and metabolism. PMID:26373795

  5. Evaluation in broilers of the probiotic properties of Pichia pastoris and a recombinant P. pastoris containing the Clostridium perfringens alpha toxin gene.

    Science.gov (United States)

    Gil de los Santos, João Rodrigo; Storch, Otávio Brod; Fernandes, Cristina Gevehr; Gil-Turnes, Carlos

    2012-05-01

    The probiotic properties of Pichia pastoris and of a recombinant P. pastoris containing the Clostridium perfringens alpha toxin gene were evaluated in broilers. One-day-old chicks randomly divided in four groups were fed with commercial feed devoid of antibacterials. The control group (1) received plain food, while the other groups were supplemented with either P. pastoris (2), the recombinant P. pastoris (3) or Bacillus cereus var. Toyoi (4). At day 49, live weights, feed efficiency and seroconversions were higher (P0.05) among the supplemented groups. Adverse reactions were not observed in histopathologic evaluation. We concluded that P. pastoris and the recombinant P. pastoris could be used as probiotics in broilers. PMID:22176763

  6. A standardised challenge model with an enterotoxigenic F4+ Escherichia coli strain in piglets assessing clinical traits and faecal shedding of fae and est-II toxin genes.

    Science.gov (United States)

    Spitzer, Franz; Vahjen, Wilfried; Pieper, Robert; Martinez-Vallespin, Beatriz; Zentek, Jürgen

    2014-12-01

    This study evaluated the effect of five feed additives on post weaning diarrhoea (PWD) in piglets challenged 3 d after weaning with an enterotoxigenic Escherichia coli strain (ETEC). In three experimental runs, a total of 84 piglets was weaned at 21 days of age and randomly assigned to seven treatments. As dietary treatment, piglets were fed a basal diet or diets with addition of bovine colostrum (0.2%), pineapple stem extract containing bromelain (0.2%), an autolysed yeast preparation (Saccharomyces cerevisiae) (0.1%), a combination of organic acids (0.7%) and a phytogenic product with thyme essential oil (0.015%). A porcine ETEC, serotype O149:K91:K88ac was given twice via oral infection on day 3 after weaning at 10(10) colony forming units/animal. One group of piglets was fed the basal diet without ETEC challenge. Traits included clinical sores, body temperature, faecal scoring and determination of faecal dry matter and the shedding of fae and est-II ETEC toxin genes. After weaning, non-challenged control piglets did not show signs of diarrhoea or impaired health, while the majority of infected piglets had a drop in body temperature, signs of diarrhoea and impaired general health. Mortality, the decrease of faecal dry matter and shedding of the toxin genes fae and est-II were not affected by the different additives. In conclusion, the ETEC challenge model induced distinct clinical signs of PWD in piglets, but the tested feed additives had no preventive effect under these conditions. PMID:25313936

  7. Bacterial toxin-antitoxin systems

    OpenAIRE

    Guglielmini, Julien; Van Melderen, Laurence

    2011-01-01

    Toxin-antitoxin (TA) systems are composed of two elements: a toxic protein and an antitoxin which is either an RNA (type I and III) or a protein (type II). Type II systems are abundant in bacterial genomes in which they move via horizontal gene transfer. They are generally composed of two genes organized in an operon, encoding a toxin and a labile antitoxin. When carried by mobile genetic elements, these small modules contribute to their stability by a phenomenon denoted as addiction. Recentl...

  8. 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

  9. Botox (Botulinum Toxin)

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Botox (Botulinum Toxin) A A A BEFORE: Crow's feet before Botox ... wrinkles. One such procedure involves the use of botulinum toxin injections. Botulinum toxin is produced by the fermentation ...

  10. Pichia acaciae Killer System: Genetic Analysis of Toxin Immunity▿

    OpenAIRE

    Paluszynski, John P.; Klassen, Roland; Meinhardt, Friedhelm

    2007-01-01

    The gene responsible for self-protection in the Pichia acaciae killer plasmid system was identified by heterologous expression in Saccharomyces cerevisiae. Resistance profiling and conditional toxin/immunity coexpression analysis revealed dose-independent protection by pPac1-2 ORF4 and intracellular interference with toxin function, suggesting toxin reinternalization in immune killer cells.

  11. Subtilase cytotoxin encoding genes are present in human, sheep and deer intimin-negative, Shiga toxin-producing Escherichia coli O128:H2.

    Science.gov (United States)

    Sánchez, Sergio; Beristain, Xabier; Martínez, Remigio; García, Alfredo; Martín, Carmen; Vidal, Dolors; Díaz-Sánchez, Sandra; Rey, Joaquín; Alonso, Juan M; Herrera-León, Silvia

    2012-10-12

    Shiga toxin-producing Escherichia coli (STEC) O128:H2 is recognised worldwide to be an important non-O157 STEC associated with human illness and in particular with causing haemolytic uraemic syndrome. This serotype is commonly isolated from sheep and is being increasingly isolated from deer. We determined the virulence profile and genetic relationships of one human, six sheep and five deer intimin-negative STEC O128:H2 strains isolated in Spain over a 7-year period. Our goals were to establish the presence of other virulence-associated factors, such as SubAB, in intimin-negative STEC O128:H2 strains involved in human disease and in that case, to determine if sheep and/or deer represent a reservoir of SubAB-positive STEC O128:H2. All the strains lacked the eae gene and carried subtilase cytotoxin (SubAB) encoding genes (subAB) and tia genes, but not saa gene, suggesting the presence of the recently identified new variant of SubAB, encoded on a putative pathogenicity island together with tia. We report for the first time the presence of subtilase cytotoxin encoding genes in intimin-negative STEC O128:H2 strains pathogenic for humans and how this finding might explain their clinical relevance despite neither carrying eae nor stx subtypes associated with severe clinical outcomes, but only stx1c and stx2b. Multilocus sequence typing analysis revealed that STEC O128:H2 strains from sheep and deer belong to the clonal lineage of STEC O128:H2 strains involved in diarrhoeal and haemorrhagic diseases in humans. Our results indicate that sheep and deer represent a reservoir of SubAB-positive STEC O128:H2 strains and thus a potential source of human infection. PMID:22622337

  12. Molecular cloning and expression of the Bacillus anthracis edema factor toxin gene: a calmodulin-dependent adenylate cyclase.

    OpenAIRE

    Tippetts, M T; Robertson, D L

    1988-01-01

    The Bacillus anthracis exotoxin is composed of a lethal factor, a protective antigen, and an edema factor (EF). EF is a calmodulin-dependent adenylate cyclase which elevates cyclic AMP levels within cells. The entire EF gene (cya) has been cloned in Escherichia coli, but EF gene expression by its own B. anthracis promoter could not be detected in E. coli. However, when the EF gene was placed downstream from the lac or the T7 promoter, enzymatically active EF was produced. The EF gene, like th...

  13. 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 < 0.05), but was unrelated to EC and enterococci RWQC. The occurrence of all other STEC markers was unrelated to any FIB RWQC. The eaeA, stx2, and stx1 genes were found in 93.3, 13.3, and in 46.7% of samples meeting FC RWQC and in 91.7, 0.0, and 37.5% of samples meeting the EC RWQC. Although not statistically significant, the percentage of samples positive for each STEC marker except stx1 was lower in samples that met, as opposed to exceeded, FIB RWQC. Viable STEC were common members of the FC communities in river water throughout southern Michigan and northern Indiana, regardless of FIB RWQC. Our study indicates that further information on the occurrence of pathogens in recreational waters, and research on alternative indicators of their occurrence, may help inform water-resource management and public health decision-making. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  14. PolySearch2: a significantly improved text-mining system for discovering associations between human diseases, genes, drugs, metabolites, toxins and more.

    Science.gov (United States)

    Liu, Yifeng; Liang, Yongjie; Wishart, David

    2015-07-01

    PolySearch2 (http://polysearch.ca) is an online text-mining system for identifying relationships between biomedical entities such as human diseases, genes, SNPs, proteins, drugs, metabolites, toxins, metabolic pathways, organs, tissues, subcellular organelles, positive health effects, negative health effects, drug actions, Gene Ontology terms, MeSH terms, ICD-10 medical codes, biological taxonomies and chemical taxonomies. PolySearch2 supports a generalized 'Given X, find all associated Ys' query, where X and Y can be selected from the aforementioned biomedical entities. An example query might be: 'Find all diseases associated with Bisphenol A'. To find its answers, PolySearch2 searches for associations against comprehensive collections of free-text collections, including local versions of MEDLINE abstracts, PubMed Central full-text articles, Wikipedia full-text articles and US Patent application abstracts. PolySearch2 also searches 14 widely used, text-rich biological databases such as UniProt, DrugBank and Human Metabolome Database to improve its accuracy and coverage. PolySearch2 maintains an extensive thesaurus of biological terms and exploits the latest search engine technology to rapidly retrieve relevant articles and databases records. PolySearch2 also generates, ranks and annotates associative candidates and present results with relevancy statistics and highlighted key sentences to facilitate user interpretation. PMID:25925572

  15. 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

    Science.gov (United States)

    2010-01-01

    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 modules partly

  16. 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

  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. PMID:27570736

  18. Target-Driven Evolution of Scorpion Toxins.

    Science.gov (United States)

    Zhang, Shangfei; Gao, Bin; Zhu, Shunyi

    2015-01-01

    It is long known that peptide neurotoxins derived from a diversity of venomous animals evolve by positive selection following gene duplication, yet a force that drives their adaptive evolution remains a mystery. By using maximum-likelihood models of codon substitution, we analyzed molecular adaptation in scorpion sodium channel toxins from a specific species and found ten positively selected sites, six of which are located at the core-domain of scorpion α-toxins, a region known to interact with two adjacent loops in the voltage-sensor domain (DIV) of sodium channels, as validated by our newly constructed computational model of toxin-channel complex. Despite the lack of positive selection signals in these two loops, they accumulated extensive sequence variations by relaxed purifying selection in prey and predators of scorpions. The evolutionary variability in the toxin-bound regions of sodium channels indicates that accelerated substitutions in the multigene family of scorpion toxins is a consequence of dealing with the target diversity. This work presents an example of atypical co-evolution between animal toxins and their molecular targets, in which toxins suffered from more prominent selective pressure from the channels of their competitors. Our discovery helps explain the evolutionary rationality of gene duplication of toxins in a specific venomous species. PMID:26444071

  19. Role of the RS1 sequence of the cholera vibrio in amplification of the segment of plasmid DNA carrying the gene of resistance to tetracycline and the genes of cholera toxin

    International Nuclear Information System (INIS)

    The hybrid plasmid pCO107, representing cointegrate 14(2)-5(2) of two plasmids, an F-derivative (pOX38) and a PBR322-derivative (pCT105) with an RS1 sequence of the cholera vibrio cloned in its makeup, contains two copes of RS1 at the sites of union of the two plasmids. Using a tetracycline resistance marker (TcR) of the plasmid pCT105, clones were isolated which have an elevated level of resistance to tetracycline (an increase of from 4- to 30-fold). Using restriction analysis and the Southern blot method of hybridization it was shown that the increase in the level of resistance of tetracycline is associated with the amplification of pCT105 portion of the cointegrate, and that the process of amplification is governed by the presence of direct repeats of the RS1 sequence at its ends. The increase in the number of copies of the pCT105 segment, which contains in its composition the genes of cholera toxin (vct), is accompanied by an increase in toxin production

  20. The Long-Lived Nature of Clostridium perfringens Iota Toxin in Mammalian Cells Induces Delayed Apoptosis ▿

    OpenAIRE

    Hilger, Hanna; Pust, Sascha; von Figura, Guido; Kaiser, Eva; Stiles, Bradley G.; Popoff, Michel R.; Barth, Holger

    2009-01-01

    Mono-ADP ribosylation of actin by bacterial toxins, such as Clostridium perfringens iota or Clostridium botulinum C2 toxins, results in rapid depolymerization of actin filaments and cell rounding. Here we report that treatment of African green monkey kidney (Vero) cells with iota toxin resulted in delayed caspase-dependent death. Unmodified actin did not reappear in toxin-treated cells, and enzyme-active toxin was detectable in the cytosol for at least 24 h. C2 toxin showed comparable, long-l...

  1. Identification of Novel Clostridium perfringens Type E Strains That Carry an Iota Toxin Plasmid with a Functional Enterotoxin Gene

    OpenAIRE

    Miyamoto, Kazuaki; Yumine, Natsuko; Mimura, Kanako; Nagahama, Masahiro; Li, Jihong; McClane, Bruce A.; Akimoto, Shigeru

    2011-01-01

    Clostridium perfringens enterotoxin (CPE) is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe) can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid) in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened p...

  2. The high affinity selectin glycan ligand C2-O-sLex and mRNA transcripts of the core 2 β-1,6-N-acetylglusaminyltransferase (C2GnT1) gene are highly expressed in human colorectal adenocarcinomas

    International Nuclear Information System (INIS)

    The metastasis of cancer cells and leukocyte extravasation into inflamed tissues share common features. Specialized carbohydrates modified with sialyl Lewis x (sLex) antigens on leukocyte membranes are ligands for selectin adhesion molecules on activated vascular endothelial cells at inflammatory sites. The activity of the enzyme core 2 β1,6 N-acetylglucosaminyltransferase (C2GnT1) in leukocytes greatly increases their ability to bind to endothelial selectins. C2GnT1 is essential for the synthesis of core 2-branched O-linked carbohydrates terminated with sLex (C2-O-sLex). Our goal was to determine the expression profiles of C2-O-sLex in the malignant progression and metastasis of colorectal adenocarcinomas. The well characterized CHO-131 monoclonal antibody (mAb) specifically recognizes C2-O-sLex present in human leukocytes and carcinoma cells. Using CHO-131 mAb, we investigated whether C2-O-sLex was present in 113 human primary colorectal adenocarcinomas, 10 colorectal adenomas, 46 metastatic liver tumors, 28 normal colorectal tissues, and 5 normal liver tissues by immunohistochemistry. We also examined mRNA levels of the enzyme core 2 β1,6-N-acetylglucosaminyltransferase (C2GnT1) in 20 well, 15 moderately, and 2 poorly differentiated colorectal adenocarcinomas, and in 5 normal colorectal tissues by using quantitative real-time polymerase chain reactions (RT-PCR). We observed high reactivity with CHO-131 mAb in approximately 70% of colorectal carcinomas and 87% of metastatic liver tumors but a lack of reactivity in colorectal adenomas and normal colonic and liver tissues. Positive reactivity with CHO-131 mAb was very prominent in neoplastic colorectal glands of well to moderately differentiated adenocarcinomas. The most intense staining with CHO-131 mAb was observed at the advancing edge of tumors with the deepest invasive components. Finally, we analyzed C2GnT1 mRNA levels in 37 colorectal adenocarcinomas and 5 normal colorectal tissues by RT-PCR. Significantly

  3. Biologically active A-chain of the plant toxin ricin expressed from a synthetic gene in Escherichia coli.

    Science.gov (United States)

    Shire, D; Bourrié, B J; Carillon, C; Derocq, J M; Dousset, P; Dumont, X; Jansen, F K; Kaghad, M; Legoux, R; Lelong, P

    1990-09-14

    To assess the biological activity and pharmacokinetic properties of nonglycosylated ricin A-chain (RA), we have obtained the polypeptide following expression of a synthetic 842-bp RA gene in Escherichia coli. Expression of the gene was carried out using the phage T5 PN25 promoter fused to the E. coli lac operator. The RA polypeptide was synthesized in a completely soluble form and was purified in one step by immunoabsorption. It was shown to be as cytotoxic for a human cell line as both native RA and chemically deglycosylated native RA. Reconstituted whole ricin and an immunotoxin containing the recombinant RA were also biologically active. Immunotoxins made with recombinant and deglycosylated RA had similar clearance rates in vivo showing, after a short period of rapid elimination, stabilities far higher than that of an immunotoxin made with native RA. Our results show that the complete elimination of sugar side chains from the RA is not sufficient to entirely eradicate the rapid initial in vivo clearance of RA-based biologicals. PMID:2227433

  4. Sensitivity to Alternaria alternata toxin in citrus because of altered mitochondrial RNA processing

    OpenAIRE

    Ohtani, Kouhei; Yamamoto, Hiroyuki; Akimitsu, Kazuya

    2002-01-01

    Specificity in the interaction between rough lemon (Citrus jambhiri Lush.) and the fungal pathogen Alternaria alternata rough lemon pathotype is determined by a host-selective toxin, ACR-toxin. Mitochondria from rough lemon are sensitive to ACR-toxin whereas mitochondria from resistant plants, including other citrus species, are resistant. We have identified a C. jambhiri mitochondrial DNA sequence, designated ACRS (ACR-toxin sensitivity gene), that confers toxin sensitivity to Escherichia co...

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

    OpenAIRE

    Andre L.S. Reis; Maike T.M. Montanhini; Juliana V.M. Bittencourt; Maria T. Destro; Luciano S. Bersot

    2014-01-01

    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-comp...

  6. *CYANOBACTERIA AND THEIR TOXINS

    Science.gov (United States)

    Cyanobacteria, or blue-green algae, are naturally-occurring contaminants of surface waters worldwide. These photosynthesizing prokaryotes thrive in warm, shallow, nutrient-rich waters. Many produce potent toxins as secondary metabolites. Cyanobacteria toxins have been document...

  7. Botulinum toxin injection - larynx

    Science.gov (United States)

    Injection laryngoplasty; Botox-larynx: spasmodic dysphonia-BTX; Essential voice tremor (EVT)-btx; Glottic insufficiency; Percutaneous electromyography-guided botulinum toxin treatment; Percutaneous indirect laryngoscopy-guided botulinum toxin Treatment; ...

  8. Stool C. difficile toxin

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003590.htm Stool C. difficile toxin To use the sharing features on this page, please enable JavaScript. The stool C. difficile toxin test detects harmful substances produced by ...

  9. Evaluation of 3 automated real-time PCR (Xpert C. difficile assay, BD MAX Cdiff, and IMDx C. difficile for Abbott m2000 assay) for detecting Clostridium difficile toxin gene compared to toxigenic culture in stool specimens.

    Science.gov (United States)

    Yoo, Jaeeun; Lee, Hyeyoung; Park, Kang Gyun; Lee, Gun Dong; Park, Yong Gyu; Park, Yeon-Joon

    2015-09-01

    We evaluated the performance of the 3 automated systems (Cepheid Xpert, BD MAX, and IMDx C. difficile for Abbott m2000) detecting Clostridium difficile toxin gene compared to toxigenic culture. Of the 254 stool specimens tested, 87 (48 slight, 35 moderate, and 4 heavy growth) were toxigenic culture positive. The overall sensitivities and specificities were 82.8% and 98.8% for Xpert, 81.6% and 95.8% for BD MAX, and 62.1% and 99.4% for IMDx, respectively. The specificity was significantly higher in IMDx than BD MAX (P= 0.03). All stool samples underwent toxin A/B enzyme immunoassay testing, and of the 254 samples, only 29 samples were positive and 2 of them were toxigenic culture negative. Considering the rapidity and high specificity of the real-time PCR assays compared to the toxigenic culture, they can be used as the first test method for C. difficile infection/colonization. PMID:26081240

  10. Target-Driven Evolution of Scorpion Toxins

    OpenAIRE

    Shangfei Zhang; Bin Gao; Shunyi Zhu

    2015-01-01

    It is long known that peptide neurotoxins derived from a diversity of venomous animals evolve by positive selection following gene duplication, yet a force that drives their adaptive evolution remains a mystery. By using maximum-likelihood models of codon substitution, we analyzed molecular adaptation in scorpion sodium channel toxins from a specific species and found ten positively selected sites, six of which are located at the core-domain of scorpion α-toxins, a region known to interact wi...

  11. Bordetella protein toxins

    Czech Academy of Sciences Publication Activity Database

    Mašín, Jiří; Šebo, Peter; Locht, C.

    New York : Elsevier, Academic Press, 2006, s. 291-309. ISBN 978-0-12-088445-2 R&D Projects: GA AV ČR IAA5020406; GA MŠk 1M0506 Institutional research plan: CEZ:AV0Z50200510 Keywords : pertussis toxin * adenylate cyclase toxin * dermonecrotic toxin Subject RIV: EE - Microbiology, Virology

  12. Characterization of toxin plasmids in Clostridium perfringens type C isolates.

    Science.gov (United States)

    Gurjar, Abhijit; Li, Jihong; McClane, Bruce A

    2010-11-01

    Clostridium perfringens type C isolates cause enteritis necroticans in humans or necrotizing enteritis and enterotoxemia in domestic animals. Type C isolates always produce alpha toxin and beta toxin but often produce additional toxins, e.g., beta2 toxin or enterotoxin. Since plasmid carriage of toxin-encoding genes has not been systematically investigated for type C isolates, the current study used Southern blot hybridization of pulsed-field gels to test whether several toxin genes are plasmid borne among a collection of type C isolates. Those analyses revealed that the surveyed type C isolates carry their beta toxin-encoding gene (cpb) on plasmids ranging in size from ∼65 to ∼110 kb. When present in these type C isolates, the beta2 toxin gene localized to plasmids distinct from the cpb plasmid. However, some enterotoxin-positive type C isolates appeared to carry their enterotoxin-encoding cpe gene on a cpb plasmid. The tpeL gene encoding the large clostridial cytotoxin was localized to the cpb plasmids of some cpe-negative type C isolates. The cpb plasmids in most surveyed isolates were found to carry both IS1151 sequences and the tcp genes, which can mediate conjugative C. perfringens plasmid transfer. A dcm gene, which is often present near C. perfringens plasmid-borne toxin genes, was identified upstream of the cpb gene in many type C isolates. Overlapping PCR analyses suggested that the toxin-encoding plasmids of the surveyed type C isolates differ from the cpe plasmids of type A isolates. These findings provide new insight into plasmids of proven or potential importance for type C virulence. PMID:20823204

  13. Expression of progesterone metabolizing enzyme genes (AKR1C1, AKR1C2, AKR1C3, SRD5A1, SRD5A2) is altered in human breast carcinoma

    International Nuclear Information System (INIS)

    Recent evidence suggests that progesterone metabolites play important roles in regulating breast cancer. Previous studies have shown that tumorous tissues have higher 5α-reductase (5αR) and lower 3α-hydroxysteroid oxidoreductase (3α-HSO) and 20α-HSO activities. The resulting higher levels of 5α-reduced progesterone metabolites such as 5α-pregnane-3,20-dione (5αP) in tumorous tissue promote cell proliferation and detachment, whereas the 4-pregnene metabolites, 4-pregnen-3α-ol-20-one (3αHP) and 4-pregnen-20α-ol-3-one (20αDHP), more prominent in normal tissue, have the opposite (anti-cancer-like) effects. The aim of this study was to determine if the differences in enzyme activities between tumorous and nontumorous breast tissues are associated with differences in progesterone metabolizing enzyme gene expression. Semi-quantitative RT-PCR was used to compare relative expression (as a ratio of 18S rRNA) of 5αR type 1 (SRD5A1), 5αR type 2 (SRD5A2), 3α-HSO type 2 (AKR1C3), 3α-HSO type 3 (AKR1C2) and 20α-HSO (AKR1C1) mRNAs in paired (tumorous and nontumorous) breast tissues from 11 patients, and unpaired tumor tissues from 17 patients and normal tissues from 10 reduction mammoplasty samples. Expression of 5αR1 and 5αR2 in 11/11 patients was higher (mean of 4.9- and 3.5-fold, respectively; p < 0.001) in the tumor as compared to the paired normal tissues. Conversely, expression of 3α-HSO2, 3α-HSO3 and 20α-HSO was higher (2.8-, 3.9- and 4.4-fold, respectively; p < 0.001) in normal than in tumor sample. The mean tumor:normal expression ratios for 5αR1 and 5αR2 were about 35–85-fold higher than the tumor:normal expression ratios for the HSOs. Similarly, in the unmatched samples, the tumor:normal ratios for 5αR were significantly higher than the ratios for the HSOs. The study shows changes in progesterone metabolizing enzyme gene expression in human breast carcinoma. Expression of SRD5A1 (5αR1) and SRD5A2 (5αR2) is elevated, and expression of AKR1C1

  14. Invariant subvarieties of the 3-tensor space C^2C^2C^2

    OpenAIRE

    AGAOKA, Yoshio

    1994-01-01

    We classify G-invariant subvarieties of the 3-tensor space C^2C^2C^2 that are defined by polynomials with degree≤6,where G=GL(2,C)×GL(2,C)×GL(2,C). We also calculate the character fo S^p(C^2C^2C^2), determine the generators of each irreducible component of S^p(C^2C^2C^2), and obtain some curious identities between them that play a fundamental role in classifying invariant subvarieties.

  15. Role of Toxin Functional Domains in Anthrax Pathogenesis

    OpenAIRE

    Brossier, Fabien; Weber-Levy, Martine; Mock, Michele; SIRARD, Jean-Claude

    2000-01-01

    We investigated the role of the functional domains of anthrax toxins during infection. Three proteins produced by Bacillus anthracis, the protective antigen (PA), the lethal factor (LF), and the edema factor (EF), combine in pairs to produce the lethal (PA+LF) and edema (PA+EF) toxins. A genetic strategy was developed to introduce by allelic exchange specific point mutations or in-frame deletions into B. anthracis toxin genes, thereby impairing either LF metalloprotease or EF adenylate cyclas...

  16. MAPK Signaling Pathway Alters Expression of Midgut ALP and ABCC Genes and Causes Resistance to Bacillus thuringiensis Cry1Ac Toxin in Diamondback Moth

    OpenAIRE

    Zhaojiang Guo; Shi Kang; Defeng Chen; Qingjun Wu; Shaoli Wang; Wen Xie; Xun Zhu; Simon W. Baxter; Xuguo Zhou; Juan Luis Jurat-Fuentes; Youjun Zhang

    2015-01-01

    Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt) are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led to field-evolved resistance in several lepidopteran pests. Resistance to Bt Cry1Ac toxin in the diamondback moth, Plutella xylostella (L.), was previously mapped to a multigenic resistance locus (BtR-1). Here, we assembled the 3.15 Mb BtR-1 locus and found high-level resis...

  17. The effect of feeding a commercial essential oil product on Clostridium perfringens numbers in the intestine of broiler chickens measured by real-time PCR targeting the α-toxin-encoding gene (plc)

    DEFF Research Database (Denmark)

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

    2010-01-01

    Proliferation of Clostridium perfringens type A in the broiler intestinal tract is related to poor growth and litter quality, and can under certain conditions lead to the development of necrotic enteritis (NE), a severe gastrointestinal disease in broilers. The aim of the present study was to inv...... quantification of C. perfringens type A in broilers, a real-time PCR assay, targeting the α-toxin-encoding plc gene, was developed for use in ileal and caecal samples and was shown to be a fast and reliable alternative to conventional plate counting....

  18. Enterotoxigenicity of Mature 45-Kilodalton and Processed 35-Kilodalton Forms of Hemagglutinin Protease Purified from a Cholera Toxin Gene-Negative Vibrio cholerae Non-O1, Non-O139 Strain

    OpenAIRE

    Ghosh, A; Saha, D. R.; Hoque, K. M.; Asakuna, M.; Yamasaki, S.; Koley, H; Das, S. S.; Chakrabarti, M K; Pal, A.

    2006-01-01

    Cholera toxin gene-negative Vibrio cholerae non-O1, non-O139 strain PL-21 is the etiologic agent of cholera-like syndrome. Hemagglutinin protease (HAP) is one of the major secretory proteins of PL-21. The mature 45-kDa and processed 35-kDa forms of HAP were purified in the presence and absence of EDTA from culture supernatants of PL-21. Enterotoxigenicities of both forms of HAP were tested in rabbit ileal loop (RIL), Ussing chamber, and tissue culture assays. The 35-kDa HAP showed hemorrhagic...

  19. C2c2 is a single-component programmable RNA-guided RNA-targeting CRISPR effector.

    Science.gov (United States)

    Abudayyeh, Omar O; Gootenberg, Jonathan S; Konermann, Silvana; Joung, Julia; Slaymaker, Ian M; Cox, David B T; Shmakov, Sergey; Makarova, Kira S; Semenova, Ekaterina; Minakhin, Leonid; Severinov, Konstantin; Regev, Aviv; Lander, Eric S; Koonin, Eugene V; Zhang, Feng

    2016-08-01

    The clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated genes (Cas) adaptive immune system defends microbes against foreign genetic elements via DNA or RNA-DNA interference. We characterize the class 2 type VI CRISPR-Cas effector C2c2 and demonstrate its RNA-guided ribonuclease function. C2c2 from the bacterium Leptotrichia shahii provides interference against RNA phage. In vitro biochemical analysis shows that C2c2 is guided by a single CRISPR RNA and can be programmed to cleave single-stranded RNA targets carrying complementary protospacers. In bacteria, C2c2 can be programmed to knock down specific mRNAs. Cleavage is mediated by catalytic residues in the two conserved Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) domains, mutations of which generate catalytically inactive RNA-binding proteins. These results broaden our understanding of CRISPR-Cas systems and suggest that C2c2 can be used to develop new RNA-targeting tools. PMID:27256883

  20. 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.

  1. 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. PMID:24000752

  2. Cloning and characterization of an apolipoprotein C2 promoter in the mouse central nervous system

    Institute of Scientific and Technical Information of China (English)

    Zhaoyang Li; Bing Du; Shengyang Li; Xiangchuan Lv; Shenglai Zhou; Yang Yu; Wei Wang; Zhihong Zheng

    2013-01-01

    Apolipoprotein C2 is an important member of the apolipoprotein C family, and is a potent activator of lipoprotein lipase. In the central nervous system, apolipoprotein C2 plays an important role in the catabolism of triglyceride-rich lipoproteins. Studies into the exact regulatory mechanism of mouse apolipoprotein C2 expression have not been reported. In this study, seven luciferase expression vectors, which contained potential mouse apolipoprotein C2 gene promoters, were constructed and co-transfected with pRL-TK into HEK293T cells to investigate apolipoprotein C2 promoter activity. Luciferase assays indicated that the apolipoprotein C2 promoter region was mainly located in the +104 bp to +470 bp region. The activity of the different lengths of apolipoprotein C2 promoter region varied. This staggered negative-positive-negative arrangement indicates the complex regulation of apolipoprotein C2 expression and provides important clues for elucidating the regulatory mechanism of apolipoprotein C2 gene transcription.

  3. Ca2(+)-dependent interaction of N-copine, a member of the two C2 domain protein family, with OS-9, the product of a gene frequently amplified in osteosarcoma.

    Science.gov (United States)

    Nakayama, T; Yaoi, T; Kuwajima, G; Yoshie, O; Sakata, T

    1999-06-18

    N-copine is a novel two C2 domain protein that shows Ca2(+)-dependent phospholipid binding and membrane association. By using yeast two-hybrid assays, we identified OS-9 as a protein capable of interacting with N-copine. We further revealed that the second C2 domain of N-copine bound with the carboxy-terminal region of OS-9. Their interaction in vivo was also confirmed by co-immunoprecipitation from 293E cells co-expressing transfected N-copine and OS-9. In vitro binding assays showed that this interaction was Ca2(+)-dependent. By Northern blot analysis, N-copine and OS-9 were co-expressed in the same regions of human brain. These results reveal that OS-9 is a potential target of N-copine. PMID:10403379

  4. Understanding malarial toxins.

    Science.gov (United States)

    Starkl Renar, Katarina; Iskra, Jernej; Križaj, Igor

    2016-09-01

    Recognized since antiquity, malaria is one of the most infamous and widespread infectious diseases in humans and, although the death rate during the last century has been diminishing, it still accounts for more than a half million deaths annually. It is caused by the Plasmodium parasite and typical symptoms include fever, shivering, headache, diaphoresis and nausea, all resulting from an excessive inflammatory response induced by malarial toxins released into the victim's bloodstream. These toxins are hemozoin and glycosylphosphatidylinositols. The former is the final product of the parasite's detoxification of haeme, a by-product of haemoglobin catabolism, while the latter anchor proteins to the Plasmodium cell surface or occur as free molecules. Currently, only two groups of antimalarial toxin drugs exist on the market, quinolines and artemisinins. As we describe, they both target biosynthesis of hemozoin. Other substances, currently in various phases of clinical trials, are directed towards biosynthesis of glycosylphosphatidylinositol, formation of hemozoin, or attenuation of the inflammatory response of the patient. Among the innovative approaches to alleviating the effects of malarial toxins, is the development of antimalarial toxin vaccines. In this review the most important lessons learned from the use of treatments directed against the action of malarial toxins in antimalarial therapy are emphasized and the most relevant and promising directions for future research in obtaining novel antimalarial agents acting on malarial toxins are discussed. PMID:27353131

  5. Role of receptors in Bacillus thuringiensis crystal toxin activity.

    Science.gov (United States)

    Pigott, Craig R; Ellar, David J

    2007-06-01

    Bacillus thuringiensis produces crystalline protein inclusions with insecticidal or nematocidal properties. These crystal (Cry) proteins determine a particular strain's toxicity profile. Transgenic crops expressing one or more recombinant Cry toxins have become agriculturally important. Individual Cry toxins are usually toxic to only a few species within an order, and receptors on midgut epithelial cells have been shown to be critical determinants of Cry specificity. The best characterized of these receptors have been identified for lepidopterans, and two major receptor classes have emerged: the aminopeptidase N (APN) receptors and the cadherin-like receptors. Currently, 38 different APNs have been reported for 12 different lepidopterans. Each APN belongs to one of five groups that have unique structural features and Cry-binding properties. While 17 different APNs have been reported to bind to Cry toxins, only 2 have been shown to mediate toxin susceptibly in vivo. In contrast, several cadherin-like proteins bind to Cry toxins and confer toxin susceptibility in vitro, and disruption of the cadherin gene has been associated with toxin resistance. Nonetheless, only a small subset of the lepidopteran-specific Cry toxins has been shown to interact with cadherin-like proteins. This review analyzes the interactions between Cry toxins and their receptors, focusing on the identification and validation of receptors, the molecular basis for receptor recognition, the role of the receptor in resistant insects, and proposed models to explain the sequence of events at the cell surface by which receptor binding leads to cell death. PMID:17554045

  6. Positive regulation of Clostridium difficile toxins.

    OpenAIRE

    Moncrief, J S; Barroso, L A; Wilkins, T D

    1997-01-01

    The toxigenic element of Clostridium difficile VPI 10463 contains a small open reading frame (ORF) immediately upstream of the toxin B gene (G. A. Hammond and J. L. Johnson, Microb. Pathog. 19:203-213, 1995). The deduced amino acid sequence of the ORF, which we have designated txeR, encodes a 22-kDa protein which contains a helix-turn-helix motif with sequence identity to DNA binding regulatory proteins. We used a DNA fragment containing the C. difficile toxin A repeating units (ARU) as a rep...

  7. Subtype and sequence analysis of the C2-V3 region of env gene among HIV-1 infected homosexual men in Beijing%北京市同性恋HIV-1感染者的包膜基因C2-V3区序列测定和亚型分析

    Institute of Scientific and Technical Information of China (English)

    姚均; 张福杰; 何忠平; 赵红心; 李兴旺; 冯鑫; 徐克沂

    2002-01-01

    目的了解北京市同性恋HIV-1感染者HIV-1的亚型类型及传播来源和流行时间.方法应用套式聚合酶链式反应(PCR)对12份1993~2001年北京市HIV-1阳性同性恋者外周血单个核细胞(PBMC)的核酸样品进行扩增,并对其包膜区的C2-V3段的306个核酸序列进行测定和分析.结果 12份样品全部是B亚型的HIV-1毒株序列,其亚型内的基因离散率为10.35±2.06,与国际A-E亚型共享序列比较后发现其与A、C、D、E亚型的共享序列的基因离散率均大于25%,而与国际B亚型共享序列的基因离散率仅为11.25±3.60.系统树分析显示,12个毒株与B亚型共享序列聚在一起并远离其它国际亚型,并且12个毒株与SF162 紧密相连,而与国际B亚型共享序列和泰国B亚型代表株TH14可以分开.对gp120中最重要的中和抗体决定簇V3环序列进行对比分析发现,12毒株在V3环中变化较大,其中4毒株带有GPGR这一欧美B亚型V3环顶端四肽序列特征,占33.33%,1个毒株带有GLGR,占8.33%,而其它7个毒株为GWGR,占58.34%.结论 HIV-1 在北京市同性恋人群中流行的为B亚型,流行来源为欧美,流行时间10年左右,V3 环顶端四肽序列特征以 GWGR 为主.

  8. 转Bt毒蛋白基因玉米及其抗虫性研究进展%Transgenic Corn with Bt Toxin Protein Gene and Insect-resistance

    Institute of Scientific and Technical Information of China (English)

    杨春英; 宋建成

    2001-01-01

    本文从转Bt毒蛋白基因玉米的培育及商品化,Bt毒蛋白基因在转基因玉米中的遗传分离与整合、对玉米螟及其它害虫的杀虫效果、对天敌种群数量和玉米病害发生程度的影响、玉米螟对转Bt毒蛋白基因玉米产生抗性及解决措施、应用转Bt毒蛋白基因玉米潜在的生态风险性等方面对国内外最新研究进展进行了综述。%This review briefly focused on the progress at home and overseas in the study of transgenic corn transformed with Bt toxic protein gene,including the breeding and commercial production of transgenic corn transformed with Bt toxic protein gene,genetic segregation and combination of Bt toxin protein in transgenic corn,insecticidal effect on corn borer and other pests,influence on natural enemy population amount and corn disease,corn borer tolerance to Bt toxic protein gene and countermeasures,and the potential ecological risk of transgenic corn transformed with Bt toxic protein gene.

  9. Staphylococcus aureus toxins

    OpenAIRE

    Otto, Michael

    2013-01-01

    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 agai...

  10. The transcriptional repressor ZBP-89 and the lack of Sp1/Sp3, c-Jun, and Stat3 are important for the down-regulation of the vimentin gene during C2C12 myogenesis

    OpenAIRE

    Salmon, Morgan; Zehner, Zendra E.

    2009-01-01

    Currently, considerable information is available about how muscle-specific genes are activated during myogenesis, yet little is known about how non-muscle genes are down-regulated. The intermediate filament protein vimentin is known to be “turned off” during myogenesis to be replaced by desmin, the muscle-specific intermediate filament protein. Here, we demonstrate that vimentin down-regulation is the result of the combined effect of several transcription factors. Levels of the positive activ...

  11. A recombinant Bacillus anthracis strain producing the Clostridium perfringens Ib component induces protection against iota toxins.

    OpenAIRE

    Sirard, J C; Weber, M.; Duflot, E; Popoff, M R; Mock, M

    1997-01-01

    The Bacillus anthracis toxinogenic Sterne strain is currently used as a live veterinary vaccine against anthrax. The capacity of a toxin-deficient derivative strain to produce a heterologous antigen by using the strong inducible promoter of the B. anthracis pag gene was investigated. The expression of the foreign gene ibp, encoding the Ib component of iota toxin from Clostridium perfringens, was analyzed. A pag-ibp fusion was introduced by allelic exchange into a toxin-deficient Sterne strain...

  12. UV induction of the LT-Toxin operon with respect to the genes lexA, recA, and umuD

    International Nuclear Information System (INIS)

    UV induction of the elt operon (the LT-toxin operon in Escherichia coli) was demonstrated in experiments using fusion of elt::lac operons with the help of Mud1(Ap lac) phage. UV induction of the elt operon is lexA-dependent; thus, the possibility of SOS regulation of this process may be assumed. However, UV induction of the elt operon turned out to be recA-independent, which makes it impossible to consider this induction as a typical SOS response. UV induction of the elt operon is also observed in Salmonella typhimurium, which differs from E. coli in the product of umuD, which suggests that the UV induction of the elt operon is umuD independent

  13. Characterization of two different toxins of Wickerhamomyces anomalus (Pichia anomala) VKM Y-159.

    Science.gov (United States)

    Farkas, Z; Márki-Zay, J; Kucsera, Judit; Vágvölgyi, Cs; Golubev, W I; Pfeiffer, Ilona

    2012-06-01

    Wickerhamomyces anomalus VKM Y-159 strain produces two types of toxin designated as WAKT a and WAKT b, encoded by chromosomal genes. The WAKT a toxin is heat-labile, pronase sensitive acting in pH range 3-4 affecting on several yeasts including pathogenic Candida species while the WAKT b toxin is protease- and thermo-resistant, acting in pH range 3-7 on two species, Candida alai and Candida norvegica. The rapid decrease of the number of viable cells after toxin treatment demonstrates that both toxins have cytocidic effect. PMID:22695525

  14. Gene and protein expression and cellular localisation of cytochrome P450 enzymes of the 1A, 2A, 2C, 2D and 2E subfamilies in equine intestine and liver

    OpenAIRE

    Tydén, Eva; Tjälve, Hans; Larsson, Pia

    2014-01-01

    Background Among the cytochrome P450 enzymes (CYP), families 1–3 constitute almost half of total CYPs in mammals and play a central role in metabolism of a wide range of pharmaceuticals. This study investigated gene and protein expression and cellular localisation of CYP1A, CYP2A, CYP2C, CYP2D and CYP2E in equine intestine and liver. Real-time polymerase chain reaction (RT-PCR) was used to analyse gene expression, western blot to examine protein expression and immunohistochemical analyses to ...

  15. 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.

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

    Science.gov (United States)

    Licznerska, Katarzyna; Nejman-Faleńczyk, Bożena; Bloch, Sylwia; Dydecka, Aleksandra; Topka, Gracja; Gąsior, Tomasz; Węgrzyn, Alicja; Węgrzyn, Grzegorz

    2016-01-01

    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. PMID:26798420

  17. 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

  18. An arterial-specific enhancer of the human Endothelin-converting enzyme 1 (ECE1) gene is synergistically activated by Sox17, FoxC2, and Etv2

    OpenAIRE

    Robinson, Ashley S.; Materna, Stefan C.; Barnes, Ralston M.; De Val, Sarah; Xu, Shan-Mei; Black, Brian L.

    2014-01-01

    Endothelin-converting enzyme-1 (Ece-1), a crucial component of the Endothelin signaling pathway, is required for embryonic development and is an important regulator of vascular tone, yet the transcriptional regulation of the ECE1 gene has remained largely unknown. Here, we define the activity and regulation of an enhancer from the human ECE1 locus in vivo. The enhancer identified here becomes active in endothelial progenitor cells shortly after their initial specification and is dependent on ...

  19. Differences in the toxin profiles of Alexandrium ostenfeldii (Dinophyceae) strains isolated from different geographic origins: Evidence of paralytic toxin, spirolide, and gymnodimine.

    Science.gov (United States)

    Salgado, Pablo; Riobó, Pilar; Rodríguez, Francisco; Franco, José M; Bravo, Isabel

    2015-09-01

    Among toxin-producing dinoflagellates of the genus Alexandrium, Alexandrium ostenfeldii is the only species able to produce paralytic shellfish poisoning (PSP) toxins, spirolides (SPXs) and gymnodimines (GYMs). In this study we characterized and compared three A. ostenfeldii strains isolated from the Baltic, Mediterranean, and southern Chile Seas with respect to their toxin profiles, morphology, and phylogeny. Toxin analyses by HPLC-FD and LC-HRMS revealed differences in the toxin profiles of the three strains. The PSP toxin profiles of the southern Chile and Baltic strains were largely the same and included gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), although the total PSP toxin content of the Chilean strain (105.83 ± 72.15 pg cell(-1)) was much higher than that of the Baltic strain (4.04 ± 1.93 pg cell(-1)). However, the Baltic strain was the only strain that expressed detectable amounts of analogues of GYM-A and GYM-B/-C (48.27 ± 26.12 pg GYM-A equivalents cell(-1)). The only toxin expressed by the Mediterranean strain was 13-desmethyl SPX-C (13dMeC; 2.85 ± 4.76 pg cell(-1)). Phylogenetic analysis based on the LSU rRNA showed that the studied strains belonged to distinct molecular clades. The toxin profiles determined in this study provide further evidence of the taxonomic complexity of this species. PMID:26093028

  20. Toxins Best Paper Award 2015

    OpenAIRE

    Tesh, Vernon L.

    2015-01-01

    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 Awa...

  1. Pyrenophora bromi, causal agent of brownspot of bromegrass, expresses a gene encoding a protein with homology and similar activity to Ptr ToxB, a host-selective toxin of wheat.

    Science.gov (United States)

    Andrie, Rachael M; Ciuffetti, Lynda M

    2011-03-01

    Ptr ToxB, encoded by ToxB, is one of multiple host-selective toxins (HST) produced by the wheat pathogen Pyrenophora tritici-repentis. Homologs of ToxB are found in several ascomycetes, including sister species Pyrenophora bromi, causal agent of brownspot of bromegrass. Due to the close evolutionary relatedness of P. tritici-repentis and P. bromi and that of their grass hosts, we hypothesized that homologs of ToxB in P. bromi may act as HST in the disease interaction between P. bromi and bromegrass. A representative set of transcriptionally active P. bromi ToxB genes were heterologously expressed in Pichia pastoris and the resultant proteins tested for their ability to act as HST on bromegrass. The tested Pyrenophora bromi ToxB (Pb ToxB) proteins were not toxic to bromegrass; thus, Pb ToxB does not appear to function as an HST in the P. bromi-bromegrass interaction. Instead, we revealed that the Pb ToxB proteins can be toxic to Ptr ToxB-sensitive wheat, at levels similar to Ptr ToxB, and the corresponding P. bromi ToxB genes are expressed in P. bromi-inoculated wheat. Our data suggest that P. bromi possesses the potential to become a wheat pathogen and highlights the importance of investigating the interaction between P. bromi and wheat. PMID:21091157

  2. Botulinum Toxin Therapy

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ... toxin therapy public SPOT Skin Cancer™ Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ...

  3. 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:[...

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

    Science.gov (United States)

    Bakker, Dennis; Smits, Wiep Klaas; Kuijper, Ed J; Corver, Jeroen

    2012-01-01

    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. PMID:22912837

  5. 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.

  6. Resistance of Trichoplusia ni to Bacillus thuringiensis Toxin Cry1Ac Is Independent of Alteration of the Cadherin-Like Receptor for Cry Toxins

    OpenAIRE

    Xin Zhang; Kasorn Tiewsiri; Wendy Kain; Lihua Huang; Ping Wang

    2012-01-01

    Alteration of binding sites for Bacillus thuringiensis (Bt) toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptida...

  7. 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.

  8. Bacillus thuringiensis (Bt) toxin susceptibility and isolation of resistance mutants in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Marroquin, L D; Elyassnia, D; Griffitts, J S; Feitelson, J S; Aroian, R V

    2000-01-01

    The protein toxins produced by Bacillus thuringiensis (Bt) are the most widely used natural insecticides in agriculture. Despite successful and extensive use of these toxins in transgenic crops, little is known about toxicity and resistance pathways in target insects since these organisms are not ideal for molecular genetic studies. To address this limitation and to investigate the potential use of these toxins to control parasitic nematodes, we are studying Bt toxin action and resistance in Caenorhabditis elegans. We demonstrate for the first time that a single Bt toxin can target a nematode. When fed Bt toxin, C. elegans hermaphrodites undergo extensive damage to the gut, a decrease in fertility, and death, consistent with toxin effects in insects. We have screened for and isolated 10 recessive mutants that resist the toxin's effects on the intestine, on fertility, and on viability. These mutants define five genes, indicating that more components are required for Bt toxicity than previously known. We find that a second, unrelated nematicidal Bt toxin may utilize a different toxicity pathway. Our data indicate that C. elegans can be used to undertake detailed molecular genetic analysis of Bt toxin pathways and that Bt toxins hold promise as nematicides. PMID:10924467

  9. Toxins and drug discovery.

    Science.gov (United States)

    Harvey, Alan L

    2014-12-15

    Components from venoms have stimulated many drug discovery projects, with some notable successes. These are briefly reviewed, from captopril to ziconotide. However, there have been many more disappointments on the road from toxin discovery to approval of a new medicine. Drug discovery and development is an inherently risky business, and the main causes of failure during development programmes are outlined in order to highlight steps that might be taken to increase the chances of success with toxin-based drug discovery. These include having a clear focus on unmet therapeutic needs, concentrating on targets that are well-validated in terms of their relevance to the disease in question, making use of phenotypic screening rather than molecular-based assays, and working with development partners with the resources required for the long and expensive development process. PMID:25448391

  10. Tobacco plants expressing the Cry1AbMod toxin suppress tolerance to Cry1Ab toxin of Manduca sexta cadherin-silenced larvae.

    Science.gov (United States)

    Porta, Helena; Jiménez, Gladys; Cordoba, Elizabeth; León, Patricia; Soberón, Mario; Bravo, Alejandra

    2011-07-01

    Cry toxins produced by Bacillus thuringiensis bacteria are insecticidal proteins used worldwide in the control of different insect pests. Alterations in toxin-receptor interaction represent the most common mechanism to induce resistance to Cry toxins in lepidopteran insects. Cry toxins bind with high affinity to the cadherin protein present in the midgut cells and this interaction facilitates the proteolytic removal of helix α-1 and pre-pore oligomer formation. Resistance to Cry toxins has been linked with mutations in the cadherin gene. One strategy effective to overcome larval resistance to Cry1A toxins is the production of Cry1AMod toxins that lack helix α-1. Cry1AMod are able to form oligomeric structures without binding to cadherin receptor and were shown to be toxic to cadherin-silenced Manduca sexta larvae and Pectinophora gossypiella strain with resistance linked to mutations in a cadherin gene. We developed Cry1AbMod tobacco transgenic plants to analyze if Cry1AMod toxins can be expressed in transgenic crops, do not affect plant development and are able to control insect pests. Our results show that production of the Cry1AbMod toxin in transgenic plants does not affect plant development, since these plants exhibited healthy growth, produced abundant seeds, and were virtually undistinguishable from control plants. Most importantly, Cry1AbMod protein produced in tobacco plants retains its functional toxic activity against susceptible and tolerant M. sexta larvae due to the silencing of cadherin receptor by RNAi. These results suggest that CryMod toxins could potentially be expressed in other transgenic crops to protect them against both toxin-susceptible and resistant lepidopteran larvae affected in cadherin gene. PMID:21621616

  11. 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.

  12. 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.

  13. Intense laser induced field ionization of C2H2, C2H4,and C2H6

    Institute of Scientific and Technical Information of China (English)

    GAO Lirong; JI Na; XONG Yijia; TANG Xiaoping; KONG Fan'ao

    2003-01-01

    Using HOMO Field Ionization Model, the tunneling probabilities and the theoretical threshold intensities of the field ionizations of acetylene, ethylene, and ethane in intense laser field are calculated. C2H2, C2H4, and C2H6 were irradiated by 800 nm, 100 fs laser pulses with the intensity range of 1013-1014 W/cm2. A TOF-mass spectrometer was coupled to the laser system and used to experimentally investigate the field ionization of these molecules. The experimental ionization threshold intensities are obtained. The calculating results of the three molecules agree well with the experimental results, indicating that HOMO Field Ionization Model is valid for the ionization of polyatomic molecules in intense laser field.

  14. Clostridium difficile binary toxin CDT

    OpenAIRE

    Gerding, Dale N.; Johnson, Stuart; Rupnik, Maja; Aktories, Klaus

    2013-01-01

    Binary toxin (CDT) is frequently observed in Clostridium difficile strains associated with increased severity of C. difficile infection (CDI). CDT belongs to the family of binary ADP-ribosylating toxins consisting of two separate toxin components: CDTa, the enzymatic ADP-ribosyltransferase which modifies actin, and CDTb which binds to host cells and translocates CDTa into the cytosol. CDTb is activated by serine proteases and binds to lipolysis stimulated lipoprotein receptor. ADP-ribosylatio...

  15. 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.

  16. Identification and Characterization of a Novel Host-Toxin Interaction in the Wheat - Stagonospora Nodorum Pathosystem

    Science.gov (United States)

    Stagonospora nodorum, casual agent of Stagonospora nodorum blotch (SNB) of wheat, produces a number of host-selective toxins (HSTs) known to be important in disease. To date, four HSTs and corresponding host sensitivity genes have been reported, and all four host-toxin interactions are significant f...

  17. Clostridium Perfringens Toxins Involved in Mammalian Veterinary Diseases.

    Science.gov (United States)

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

    2010-01-01

    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

  18. Regulation of toxin production by Bacillus cereus and its food safety implications.

    Science.gov (United States)

    Ceuppens, Siele; Rajkovic, Andreja; Heyndrickx, Marc; Tsilia, Varvara; Van De Wiele, Tom; Boon, Nico; Uyttendaele, Mieke

    2011-08-01

    Toxin expression is of utmost importance for the food-borne pathogen B. cereus, both in food poisoning and non-gastrointestinal host infections as well as in interbacterial competition. Therefore it is no surprise that the toxin gene expression is tightly regulated by various internal and environmental signals. An overview of the current knowledge regarding emetic and diarrheal toxin transcription and expression is presented in this review. The food safety aspects and management tools such as temperature control, food preservatives and modified atmosphere packaging are discussed specifically for B. cereus emetic and diarrheal toxin production. PMID:21417966

  19. Toxin(s), Other Than Cholera Toxin, Produced by Environmental Non O1 Non O139 Vibrio cholerae

    Institute of Scientific and Technical Information of China (English)

    Kohinur Begum; Chowdhury R. Ahsan; Mohammad Ansaruzzaman; Dilip K. Dutta; Qazi S.Ahmad; Kaisar A. Talukder

    2006-01-01

    A total of 39 Vibrio cholerae non O1 non O139 strains were isolated from surface waters of different parts of Dhaka City, Bangladesh. All these strains showed lack of ctx or zot gene, as demonstrated by the PCR analysis.Eighteen representative strains were tested for enterotoxin production using a rabbit ileal loop model, of which live cells of 8 strains and culture filtrates of 6 strains produced fluid accumulation in ileal loops. However, none of them produced heat stable toxin (ST), as detected by suckling mouse assay. On the other hand, 15% of isolates produced cytotoxin as detected by the Chinese Hamster Ovary (CHO) cell assay. Fifty times concentrated culture filtrates of the representative strains did not give any precipitin band against the anti-cholera toxin, suggesting the strains produced an enterotoxin, which is antigenically different from known cholera toxin (CT). Eighty percent of the total isolates were found to be positive for heat labile haemolysin detected by tube method, whereas, 39% were found positive by the Christie-Atkins-Munch-Petersen (CAMP) method. However, 87% of the isolates were positive for haemagglutinin/protease and all of the strains were positive for mannose-sensitive-haemagglutinin assay.

  20. Requirements for anthrax toxin entry into cells

    OpenAIRE

    Ryan, Patricia Lynn

    2010-01-01

    Bacillus anthracis secretes a harmful exotoxin called anthrax toxin. Anthrax toxin has deleterious effects on several host cell types and is a significant contributor to anthrax pathogenesis. Toxin-deleted strains of B. anthracis are highly attenuated and many of the symptoms of anthrax can be replicated with anthrax toxin alone. Anthrax toxin is an AB-type toxin with two catalytic A moieties. PA, the B moiety, is responsible for receptor binding, pore formation and translocation of the catal...

  1. Shiga Toxin Detection Methods : A Short Review

    OpenAIRE

    Guerrero, Y. Castaño; González-Aguilar, G.

    2013-01-01

    The Shiga toxins comprise a family of related protein toxins secreted by certain types of bacteria. Shigella dysenteriae, some strain of Escherichia coli and other bacterias can express toxins which caused serious complication during the infection. Shiga toxin and the closely related Shiga-like toxins represent a group of very similar cytotoxins that may play an important role in diarrheal disease and hemolytic-uremic syndrome. The outbreaks caused by this toxin raised serious public health c...

  2. Infrared intensities and optical constants of crystalline C 2H 4 and C 2D 4

    Science.gov (United States)

    Zhao, G.; Ospina, M. J.; Khanna, R. K.

    Infrared absorption spectra of several thin films of C 2H 4 and C 2D 4 at ˜55 K were investigated at ˜0.6 cm -1 resolution. The integrated band intensities of the infrared active fundamental modes were obtained by a linear fit of the integrated absorbances vs film thickness. An iterative Kramers—Kronig analysis of the absorption data was carried out to obtain the complex refractive indices of crystalline C 2H 4 and C 2D 4 in the regions of absorption bands.

  3. 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. PMID:24787554

  4. New C2 synchondrosal fracture classification system

    International Nuclear Information System (INIS)

    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.)

  5. 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.)

  6. Lymphocyte receptors for pertussis toxin

    International Nuclear Information System (INIS)

    We have investigated human T-lymphocyte receptors for pertussis toxin by affinity isolation and photoaffinity labeling procedures. T lymphocytes were obtained from peripheral human blood, surface iodinated, and solubilized in Triton X-100. The iodinated mixture was then passed through pertussis toxin-agarose, and the fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autoradiography of the fixed, dried gels revealed several bands in the pertussis toxin-bound fraction that were not observed in fractions obtained from histone or fetuin-agarose. Further investigations employed a photoaffinity labeling reagent, sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate, to identify pertussis toxin receptors in freshly isolated peripheral blood monocytic cells, T lymphocytes, and Jurkat cells. In all three cell systems, the pertussis toxin affinity probe specifically labeled a single protein species with an apparent molecular weight of 70,000 that was not observed when the procedure was performed in the presence of excess unmodified pertussis toxin. A protein comparable in molecular weight to the one detected by the photoaffinity labeling technique was also observed among the species that bound to pertussis toxin-agarose. The results suggest that pertussis toxin may bind to a 70,000-Da receptor in human T lymphocytes

  7. Three toxins, two receptors, one mechanism: Mode of action of Cry1A toxins from Bacillus thuringiensis in Heliothis virescens.

    Science.gov (United States)

    Bretschneider, Anne; Heckel, David G; Pauchet, Yannick

    2016-09-01

    Insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) are highly active against Lepidoptera. However, field-evolved resistance to Bt toxins is on the rise. The 12-cadherin domain protein HevCaLP and the ABC transporter HevABCC2 are both genetically linked to Cry toxin resistance in Heliothis virescens. We investigated their interaction using stably expressing non-lytic clonal Sf9 cell lines expressing either protein or both together. Untransfected Sf9 cells are innately sensitive to Cry1Ca toxin, but not to Cry1A toxins; and quantitative PCR revealed negligible expression of genes involved in Cry1A toxicity such as cadherin, ABCC2, alkaline phosphatase (ALP) and aminopeptidase N (APN). Cry1Aa, Cry1Ab or Cry1Ac caused swelling of Sf9 cells expressing HevABCC2, and caused faster swelling, lysis and up to 86% mortality in cells expressing both proteins. No such effect was observed in control Sf9 cells or in cells expressing only HevCaLP. The results of a mixing experiment demonstrated that both proteins need to be expressed within the same cell for high cytotoxicity, and suggest a novel role for HevCaLP. Binding assays showed that the toxin-receptor interaction is specific. Our findings confirm that HevABCC2 is the central target in Cry1A toxin mode of action, and that HevCaLP plays a supporting role in increasing Cry1A toxicity. PMID:27456115

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

    Science.gov (United States)

    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

    2016-08-01

    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 forming basidiomycete using Agrobacterium-mediated transformation. Morphology, cap expansion rate, and total number and biomass of mushrooms were not affected by over-expression of c2h2. However, yield per day of the c2h2 over-expression strains peaked 1 day earlier. These data and expression analysis indicate that C2H2 impacts timing of mushroom formation at an early stage of development, making its encoding gene a target for breeding of commercial mushroom strains. PMID:27207144

  9. Toxin-Based Therapeutic Approaches

    Directory of Open Access Journals (Sweden)

    Itai Benhar

    2010-10-01

    Full Text Available Protein toxins confer a defense against predation/grazing or a superior pathogenic competence upon the producing organism. Such toxins have been perfected through evolution in poisonous animals/plants and pathogenic bacteria. Over the past five decades, a lot of effort has been invested in studying their mechanism of action, the way they contribute to pathogenicity and in the development of antidotes that neutralize their action. In parallel, many research groups turned to explore the pharmaceutical potential of such toxins when they are used to efficiently impair essential cellular processes and/or damage the integrity of their target cells. The following review summarizes major advances in the field of toxin based therapeutics and offers a comprehensive description of the mode of action of each applied toxin.

  10. Suppression subtractive hybridization and comparative expression of a pore-forming toxin and glycosyl hydrolase genes in Rhizoctonia solani during potato sprout infection.

    Science.gov (United States)

    Chamoun, Rony; Samsatly, Jamil; Pakala, Suman B; Cubeta, Marc A; Jabaji, Suha

    2015-06-01

    Rhizoctonia solani is a plant pathogenic fungus that causes black scurf on tubers and stem and stolon canker on underground parts of potato plant. Early in the season, the fungus attacks germinating sprouts underground before they emerge from the soil. Damage at this stage results in delayed emergence of weakened plants with poor and uneven stands. The mechanism underlying this phenomenon has been investigated in this study by coupling a cDNA-suppression subtractive hybridization (SSH) library to differential screening to identify transcripts of R. solani that are down-regulated during infection of potato sprouts. We report on the identification of 33 unique genes with functions related to carbohydrate binding, vitamin synthesis, pathogenicity, translation, ATP and nucleic acid binding and other categories. RACE-PCR was used to clone and characterize the first full-length cDNA clones, RSENDO1 and RSGLYC1 that encode for an eukaryotic delta-endotoxin CytB protein and an intracellular glycosyl hydrolase, respectively. Quantitative real-time PCR revealed the down-regulation of RSENDO1 during infection of potato sprouts and the up-regulation of RSGLYC1 when the fungus was grown on a cellulose-based nutrient medium. In contrast, additional experiments have highlighted the down-regulation of RSENDO1 when R. solani was co-cultured with the mycoparasite Stachybotrys elegans and the bacterial antagonist Bacillus subtilis B26. These results advance our understanding of R. solani-potato interaction in subterranean parts of the plant. Such approaches could be considered in building an efficient integrated potato disease management program. PMID:25472038

  11. Synthesis of 1-C2H3 theophylline and 3-C2H3 theophylline

    International Nuclear Information System (INIS)

    This article describes a three step-selective deuteration method of 1-methyl and 3-methylxanthine, after protection of the N-7 position by chloromethylpivalate and alkylation by trideuteromethyl iodide ; yielding 1-C2H3 and 3-C2H3 theophylline. (author)

  12. Clostridium difficile toxin synthesis is negatively regulated by TcdC.

    Science.gov (United States)

    Dupuy, B; Govind, R; Antunes, A; Matamouros, S

    2008-06-01

    Clostridium difficile toxin synthesis is growth phase-dependent and is regulated by various environmental signals. The toxin genes tcdA and tcdB are located in a pathogenicity locus, which also includes three accessory genes, tcdR, tcdC and tcdE. TcdR has been shown to act as an alternative sigma factor that mediates positive regulation of both the toxin genes and its own gene. The tcdA, tcdB and tcdR genes are transcribed during the stationary growth phase. The tcdC gene, however, is expressed during exponential phase. This expression pattern suggested that TcdC may act as a negative regulator of toxin gene expression. TcdC is a small acidic protein without any conserved DNA-binding motif. It is able to form dimers and its N-terminal region includes a putative transmembrane domain. Genetic and biochemical evidence showed that TcdC negatively regulates C. difficile toxin synthesis by interfering with the ability of TcdR-containing RNA polymerase to recognize the tcdA and tcdB promoters. In addition, the C. difficile NAP1/027 epidemic strains that produce higher levels of toxins have mutations in tcdC. Interestingly, a frameshift mutation at position 117 of the tcdC coding sequence seems to be, at least in part, responsible for the hypertoxigenicity phenotype of these epidemic strains. PMID:18480323

  13. Influence of Environmental Factors on the Paralytic Shellfish Toxin Content and Profile of Alexandrium catenella (Dinophyceae Isolated from the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Véronique Savar

    2013-05-01

    Full Text Available Laboratory experiments were designed to study the toxin content and profile of the Alexandrium catenella strain ACT03 (isolated from Thau Lagoon, French Mediterranean in response to abiotic environmental factors under nutrient-replete conditions. This dinoflagellate can produce various paralytic shellfish toxins with concentrations ranging from 2.9 to 50.3 fmol/cell. The toxin profile was characterized by carbamate toxins (GTX3, GTX4 and GTX5 and N-sulfocarbamoyl toxins (C1, C2, C3 and C4. C2 dominated at 12–18 °C, but only for salinities ranging from 10 to 25 psu, whereas GTX5 became dominant at temperatures ranging from 21 to 30 °C at almost all salinities. There was no significant variation in the cellular toxin amount from 18 °C to 27 °C for salinities ranging between 30 and 40 psu. At salinities of 10 to 25 psu, the toxin concentrations always remained below 20 fmol/cell. Toxin content was stable for irradiance ranging from 10 to 70 μmol photons/m2/s then slightly increased. Overall, the toxin profile was more stable than the toxin content (fmol/cell, except for temperature and/or salinity values different from those recorded during Alexandrium blooms in Thau Lagoon.

  14. 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

    2016-02-01

    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. PMID:26907343

  15. 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.

  16. Clostridium difficile toxin expression is inhibited by the novel regulator TcdC.

    Science.gov (United States)

    Matamouros, Susana; England, Patrick; Dupuy, Bruno

    2007-06-01

    Clostridium difficile, an emerging nosocomial pathogen of increasing clinical significance, produces two large protein toxins that are responsible for the cellular damage associated with the disease. The precise mechanisms by which toxin synthesis is regulated in response to environmental change have yet to be discovered. The toxin genes (tcdA and tcdB) are located in a pathogenicity locus (PaLoc), along with tcdR and tcdC. TcdR is an alternative RNA polymerase sigma factor that directly activates toxin gene expression, while the inverse relationship between expression of tcdR, tcdA and tcdB genes on the one hand and tcdC on the other has led to the suggestion that TcdC somehow interferes with toxin gene expression. This idea is further supported by the finding that many recent C. difficile epidemic strains in which toxin production is increased carry a common tcdC deletion mutation. In this report we demonstrate that TcdC negatively regulates toxin synthesis both in vivo and in vitro. TcdC destabilizes the TcdR-containing holoenzyme before open complex formation, apparently by interaction with TcdR or TcdR-containing RNA polymerase holoenzyme or both. In addition, we show that the hypertoxigenicity phenotype of C. difficile epidemic strains is not due to their common 18 bp in-frame deletion in tcdC. PMID:17542920

  17. Clostridium difficile Toxins A and B: Insights into Pathogenic Properties and Extraintestinal Effects

    Science.gov (United States)

    Di Bella, Stefano; Ascenzi, Paolo; Siarakas, Steven; Petrosillo, Nicola; di Masi, Alessandra

    2016-01-01

    Clostridium difficile infection (CDI) has significant clinical impact especially on the elderly and/or immunocompromised patients. The pathogenicity of Clostridium difficile is mainly mediated by two exotoxins: toxin A (TcdA) and toxin B (TcdB). These toxins primarily disrupt the cytoskeletal structure and the tight junctions of target cells causing cell rounding and ultimately cell death. Detectable C. difficile toxemia is strongly associated with fulminant disease. However, besides the well-known intestinal damage, recent animal and in vitro studies have suggested a more far-reaching role for these toxins activity including cardiac, renal, and neurologic impairment. The creation of C. difficile strains with mutations in the genes encoding toxin A and B indicate that toxin B plays a major role in overall CDI pathogenesis. Novel insights, such as the role of a regulator protein (TcdE) on toxin production and binding interactions between albumin and C. difficile toxins, have recently been discovered and will be described. Our review focuses on the toxin-mediated pathogenic processes of CDI with an emphasis on recent studies. PMID:27153087

  18. Daphnia magna negatively affected by chronic exposure to purified Cry-toxins.

    Science.gov (United States)

    Bøhn, Thomas; Rover, Carina Macagnan; Semenchuk, Philipp Robert

    2016-05-01

    Cry-toxin genes originating from Bacillus thuringiensis are inserted into genetically modified (GM) plants, often called Bt-plants, to provide insect resistance to pests. Significant amounts of Bt-plant residues, and thus Cry-toxins, will be shed to soil and aquatic environments. We exposed Daphnia magna to purified Cry1Ab and Cry2Aa toxins for the full life-span of the animals. We used single toxins in different doses and combinations of toxins and Roundup(®), another potential stressor on the rise in agricultural ecosystems. Animals exposed to 4.5 mg/L (ppm) of Cry1Ab, Cry2Aa and the combination of both showed markedly higher mortality, smaller body size and very low juvenile production compared to controls. Animals exposed to 0.75 mg/L also showed a tendency towards increased mortality but with increased early fecundity compared to the controls. Roundup(®) stimulated animals to strong early reproductive output at the cost of later rapid mortality. We conclude that i) purified Cry-toxins in high concentrations are toxic to D. magna, indicating alternative modes-of-action for these Cry-toxins; ii) Cry-toxins act in combination, indicating that 'stacked events' may have stronger effects on non-target organisms; iii) further studies need to be done on combinatorial effects of multiple Cry-toxins and herbicides that co-occur in the environment. PMID:26993955

  19. 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 of the...

  20. [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. PMID:26449578

  1. Selection of a Clostridium perfringens type D epsilon toxin producer via dot-blot test.

    Science.gov (United States)

    Gonçalves, Luciana A; Lobato, Zélia I P; Silva, Rodrigo O S; Salvarani, Felipe M; Pires, Prhiscylla S; Assis, Ronnie A; Lobato, Francisco C F

    2009-11-01

    Clostridium perfringens type D produces enterotoxemia, an enteric disease in ruminants, also known as pulpy kidney disease. Caused by epsilon toxin, enterotoxemia is a major exotoxin produced by this microorganism. Epsilon toxin is also the main component of vaccines against this enteric disorder. In this study, a standardized dot-blot was used to choose strains of C. perfringens type D that are producers of epsilon toxin. Clones producing epsilon toxin were chosen by limiting dilution; after three passages, lethal minimum dose titers were determined by soroneutralization test in mice. These clones produced epsilon toxin 240 times more concentrated than the original strain. The presence of the epsilon toxin gene (etx) was verified by polymerase chain reaction. All clones were positive, including those determined to be negative by dot-blot tests, suggesting that mechanisms in addition to the presence of the etx gene can influence toxin production. The dot-blot test was efficient for the selection of toxigenic colonies of C. perfringens type D and demonstrated that homogeneous populations selected from toxigenic cultures produce higher titers of epsilon toxin. PMID:19779698

  2. Detection of extracellular toxin(s) produced by Vibrio vulnificus.

    OpenAIRE

    Kreger, A; Lockwood, D.

    1981-01-01

    Conditions are described for the production, in high titers, a heat-labile, antigenic, extracellular toxin(s) by Vibrio vulnificus, a recently recognized human pathogen. Bacteriologically sterile culture filtrate preparations obtained from mid-logarithmic-phase cultures of the bacterium possessed cytolytic activity against mammalian erythrocytes, cytotoxic activity for Chinese hamster ovary cells, vascular permeability factor activity in guinea pig skin, and lethal activity for mice. The spec...

  3. Epsilon toxin: a fascinating pore-forming toxin.

    Science.gov (United States)

    Popoff, Michel R

    2011-12-01

    Epsilon toxin (ETX) is produced by strains of Clostridium perfringens classified as type B or type D. ETX belongs to the heptameric β-pore-forming toxins including aerolysin and Clostridium septicum alpha toxin, which are characterized by the formation of a pore through the plasma membrane of eukaryotic cells consisting in a β-barrel of 14 amphipatic β strands. By contrast to aerolysin and C. septicum alpha toxin, ETX is a much more potent toxin and is responsible for enterotoxemia in animals, mainly sheep. ETX induces perivascular edema in various tissues and accumulates in particular in the kidneys and brain, where it causes edema and necrotic lesions. ETX is able to pass through the blood-brain barrier and stimulate the release of glutamate, which accounts for the symptoms of nervous excitation observed in animal enterotoxemia. At the cellular level, ETX causes rapid swelling followed by cell death involving necrosis. The precise mode of action of ETX remains to be determined. ETX is a powerful toxin, however, it also represents a unique tool with which to vehicle drugs into the central nervous system or target glutamatergic neurons. PMID:21535407

  4. The C2-hydrocarbon link in cometary comae

    Science.gov (United States)

    Weiler, M.; Bockelee-Morvan, D.; Hutsemekers, D.; Jehin, E.; Manfroid, J.; Muinonen, K.; Oszkiewicz, D. A.; Schulz, R.; Stuewe, J.

    2012-09-01

    Comet 8P/Tuttle was the target of an ESO multiwavelength observing campaign in 2008. Observations of the spatial distribution of C2 and C3 were obtained, as well as simultaneous direct detections of the C2 parent species C2H2 and C2H6. We combine these observations to investigate the origin of cometary C2. The observed C2 column densities are inconsistent with a production of C2 from C2H2, C2H6, and C3. Based on a photochemical model, we quantitatively discuss the influence of further potential C2 parent species. The assumption of C4H2 as an additional C2 parent species in comet 8P/Tuttle provides the best explanation for the observed C2 column densities.

  5. Genetic determinants of lactococcal C2viruses for host infection and their role in phage evolution.

    Science.gov (United States)

    Millen, Anne M; Romero, Dennis A

    2016-08-01

    Lactococcus lactis is an industrial starter culture used for the production of fermented dairy products. Pip (phage infection protein) bacteriophage-insensitive mutant (BIM) L. lactis DGCC11032 was isolated following challenge of parental strain DGCC7271 with C2viruses. Over a period of industrial use, phages infecting DGCC11032 were isolated from industrial whey samples and identified as C2viruses. Although Pip is reported to be the receptor for many C2viruses including species type phage c2, a similar cell-membrane-associated protein, YjaE, was recently reported as the receptor for C2virus bIL67. Characterization of DGCC7271 BIMs following challenge with phage capable of infecting DGCC11032 identified mutations in yjaE, confirming YjaE to be necessary for infection. DGCC7271 YjaE mutants remained sensitive to the phages used to generate pip variant DGCC11032, indicating a distinction in host phage determinants. We will refer to C2viruses requiring Pip as c2-type andC2viruses that require YjaE as bIL67-type. Genomic comparisons of two c2-type phages unable to infect pip mutant DGCC11032 and four bIL67-type phages isolated on DGCC11032 confirmed the segregation of each group based on resemblance to prototypical phages c2 and bIL67, respectively. The distinguishing feature is linked to three contiguous late-expressed genes: l14-15-16 (c2) and ORF34-35-36 (bIL67). Phage recombinants in which the c2-like l14-15-16 homologue gene set was exchanged with corresponding bIL67 genes ORF34-35-36 were capable of infecting a pip mutated host. Together, these results correlate the phage genes corresponding to l14-15-16 (c2) and ORF34-35-36 (bIL67) to host lactococcal phage determinants Pip and YjaE, respectively. PMID:27389474

  6. Toxin genotyping of Clostridium perfringens field strains isolated from healthy and diseased chickens

    Directory of Open Access Journals (Sweden)

    Luca Bano

    2010-01-01

    Full Text Available Clostridium perfringens is well known as the aetiological agent of necrotic enteritis in chicken. Type A and type C are considered the C. perfringens toxin types responsible for this disease. The aim of this study was to determine the presence of genes coding for α, β, ε, ι, β2 and enterotoxin in C. perfringens field strains collected from healthy and diseased chickens. Thirty-seven C. perfringens field strains were toxin typed: all strains resulted to be toxin type A and 3 of these tested positive for the presence of the toxin β2 coding gene. Four isolates showed the cpa gene with the insertion of a group II intron. Our findings confirm the most recent results reported from different countries and the data suggest that the role of C. perfringens type C should be revaluated in the etiopathogenesis of necrotic enteritis.

  7. Toxin-Based Therapeutic Approaches

    OpenAIRE

    Itai Benhar; Assaf Shapira

    2010-01-01

    Protein toxins confer a defense against predation/grazing or a superior pathogenic competence upon the producing organism. Such toxins have been perfected through evolution in poisonous animals/plants and pathogenic bacteria. Over the past five decades, a lot of effort has been invested in studying their mechanism of action, the way they contribute to pathogenicity and in the development of antidotes that neutralize their action. In parallel, many research groups turned to explore the pharmac...

  8. Semicarbazone EGA Inhibits Uptake of Diphtheria Toxin into Human Cells and Protects Cells from Intoxication

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Mattarei, Andrea; Tehran, Domenico Azarnia; Montecucco, Cesare; Barth, Holger

    2016-01-01

    Diphtheria toxin is a single-chain protein toxin that invades human cells by receptor-mediated endocytosis. In acidic endosomes, its translocation domain inserts into endosomal membranes and facilitates the transport of the catalytic domain (DTA) from endosomal lumen into the host cell cytosol. Here, DTA ADP-ribosylates elongation factor 2 inhibits protein synthesis and leads to cell death. The compound 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA) has been previously shown to protect cells from various bacterial protein toxins which deliver their enzymatic subunits from acidic endosomes to the cytosol, including Bacillus anthracis lethal toxin and the binary clostridial actin ADP-ribosylating toxins C2, iota and Clostridium difficile binary toxin (CDT). Here, we demonstrate that EGA also protects human cells from diphtheria toxin by inhibiting the pH-dependent translocation of DTA across cell membranes. The results suggest that EGA might serve for treatment and/or prevention of the severe disease diphtheria. PMID:27428999

  9. Semicarbazone EGA Inhibits Uptake of Diphtheria Toxin into Human Cells and Protects Cells Articlefrom Intoxication.

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Mattarei, Andrea; Tehran, Domenico Azarnia; Montecucco, Cesare; Barth, Holger

    2016-01-01

    Diphtheria toxin is a single-chain protein toxin that invades human cells by receptor-mediated endocytosis. In acidic endosomes, its translocation domain inserts into endosomal membranes and facilitates the transport of the catalytic domain (DTA) from endosomal lumen into the host cell cytosol. Here, DTA ADP-ribosylates elongation factor 2 inhibits protein synthesis and leads to cell death. The compound 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA) has been previously shown to protect cells from various bacterial protein toxins which deliver their enzymatic subunits from acidic endosomes to the cytosol, including Bacillus anthracis lethal toxin and the binary clostridial actin ADP-ribosylating toxins C2, iota and Clostridium difficile binary toxin (CDT). Here, we demonstrate that EGA also protects human cells from diphtheria toxin by inhibiting the pH-dependent translocation of DTA across cell membranes. The results suggest that EGA might serve for treatment and/or prevention of the severe disease diphtheria. PMID:27428999

  10. The Regulatory Networks That Control Clostridium difficile Toxin Synthesis

    Science.gov (United States)

    Martin-Verstraete, Isabelle; Peltier, Johann; Dupuy, Bruno

    2016-01-01

    The pathogenic clostridia cause many human and animal diseases, which typically arise as a consequence of the production of potent exotoxins. Among the enterotoxic clostridia, Clostridium difficile is the main causative agent of nosocomial intestinal infections in adults with a compromised gut microbiota caused by antibiotic treatment. The symptoms of C. difficile infection are essentially caused by the production of two exotoxins: TcdA and TcdB. Moreover, for severe forms of disease, the spectrum of diseases caused by C. difficile has also been correlated to the levels of toxins that are produced during host infection. This observation strengthened the idea that the regulation of toxin synthesis is an important part of C. difficile pathogenesis. This review summarizes our current knowledge about the regulators and sigma factors that have been reported to control toxin gene expression in response to several environmental signals and stresses, including the availability of certain carbon sources and amino acids, or to signaling molecules, such as the autoinducing peptides of quorum sensing systems. The overlapping regulation of key metabolic pathways and toxin synthesis strongly suggests that toxin production is a complex response that is triggered by bacteria in response to particular states of nutrient availability during infection. PMID:27187475

  11. Characterizations of Clinical Isolates of Clostridium difficile by Toxin Genotypes and by Susceptibility to 12 Antimicrobial Agents, Including Fidaxomicin (OPT-80) and Rifaximin: a Multicenter Study in Taiwan

    OpenAIRE

    Liao, Chun-Hsing; Ko, Wen-Chien; Lu, Jang-Jih; Hsueh, Po-Ren

    2012-01-01

    A total of 403 nonduplicate isolates of Clostridium difficile were collected at three major teaching hospitals representing northern, central, and southern Taiwan from January 2005 to December 2010. Of these 403 isolates, 170 (42.2%) were presumed to be nontoxigenic due to the absence of genes for toxins A or B or binary toxin. The remaining 233 (57.8%) isolates carried toxin A and B genes, and 39 (16.7%) of these also had binary toxin genes. The MIC90 of all isolates for fidaxomicin and rifa...

  12. Fusarial toxins: secondary metabolites of Fusarium fungi.

    Science.gov (United States)

    Nesic, Ksenija; Ivanovic, Snezana; Nesic, Vladimir

    2014-01-01

    Exposure to mycotoxins occurs worldwide, even though there are geographic and climatic differences in the amounts produced and occurrence of these substances.Mycotoxins are secondary chemical metabolites of different fungi. They are natural contaminants of cereals, so their presence is often inevitable. Among many genera that produce mycotoxins, Fusarium fungi are the most widespread in cereal-growing areas of the planet. Fusarium fungi produce a diversity of mycotoxin types, whose distributions are also diverse. What is produced and where it is produced is influenced primarily by environmental conditions, and crop production and storage methods. The amount of toxin produced depends on physical (viz., moisture, relative humidity, temperature, and mechanical damage), chemical (viz., carbon dioxide,oxygen, composition of substrate, insecticides and fungicides), and biological factors (viz., plant variety, stress, insects, spore load, etc.). Moisture and temperature have a major influence on mold growth rate and mycotoxin production.Among the most toxic and prevalent fusaria) toxins are the following: zearalenone,fumonisins, moniliformin and trichothecenes (T-2/HT-2 toxin, deoxynivalenol,diacetoxyscirpenol, nivalenol). Zearalenone (ZEA; ZON, F-2 toxin) isaphy to estrogenic compound, primarily a field contaminant, which exhibits estrogenic activity and has been implicated in numerous mycotoxicoses of farm animals,especially pigs. Recently, evidence suggests that ZEA has potential to stimulate the growth of human breast cancer cells. Fumonisins are also cancer-promoting metabolites,of which Fumonisin 8 I (FBI) is the most important. Moniliformin (MON) isalso highly toxic to both animals and humans. Trichothecenes are classified as gastrointestinal toxins, dermatotoxins, immunotoxins, hematotoxins, and gene toxins.T-2 and HT-2 toxin, and diacetoxyscirpenol (DAS, anguidine) are the most toxic mycotoxins among the trichothecene group. Deoxynivalenol (DON, vomitoxin) and

  13. Human hypervirulent Clostridium difficile strains exhibit increased sporulation as well as robust toxin production.

    Science.gov (United States)

    Merrigan, Michelle; Venugopal, Anilrudh; Mallozzi, Michael; Roxas, Bryan; Viswanathan, V K; Johnson, Stuart; Gerding, Dale N; Vedantam, Gayatri

    2010-10-01

    Toxigenic Clostridium difficile strains produce two toxins (TcdA and TcdB) during the stationary phase of growth and are the leading cause of antibiotic-associated diarrhea. C. difficile isolates of the molecular type NAP1/027/BI have been associated with severe disease and hospital outbreaks worldwide. It has been suggested that these "hypervirulent" strains produce larger amounts of toxin and that a mutation in a putative negative regulator (TcdC) allows toxin production at all growth phases. To rigorously explore this possibility, we conducted a quantitative examination of the toxin production of multiple hypervirulent and nonhypervirulent C. difficile strains. Toxin gene (tcdA and tcdB) and toxin gene regulator (tcdR and tcdC) expression was also monitored. To obtain additional correlates for the hypervirulence phenotype, sporulation kinetics and efficiency were measured. In the exponential phase, low basal levels of tcdA, tcdB, and tcdR expression were evident in both hypervirulent and nonhypervirulent strains, but contrary to previous assumptions, toxin levels were below the detectable thresholds. While hypervirulent strains displayed robust toxin production during the stationary phase of growth, the amounts were not significantly different from those of the nonhypervirulent strains tested; further, total toxin amounts were directly proportional to tcdA, tcdB, and tcdR gene expression. Interestingly, tcdC expression did not diminish in stationary phase, suggesting that TcdC may have a modulatory rather than a strictly repressive role. Comparative genomic analyses of the closely related nonhypervirulent strains VPI 10463 (the highest toxin producer) and 630 (the lowest toxin producer) revealed polymorphisms in the tcdR ribosome binding site and the tcdR-tcdB intergenic region, suggesting that a mechanistic basis for increased toxin production in VPI 10463 could be increased TcdR translation and read-through transcription of the tcdA and tcdB genes

  14. Análisis del efecto del gen DJ-1 frente a C2-Ceramida, 6-Hidroxidopamina y rotenona y su relación con la vía PI3K/AKT en un modelo de neuronas mesencefálicas / Effect analysis of DJ-1 gene front to C2-Ceramide, 6-Hidroxidopamine and rotenone and its relation with the PI3K/AKT pathway in a model of mesencephalic neurons

    OpenAIRE

    Jaramillo Gómez, Jenny Andrea

    2010-01-01

    La enfermedad de Parkinson (EP) es un desorden neurodegenerativo caracterizado por pérdida progresiva de neuronas dopaminérgicas de la sustancia nigra y acumulación de cuerpos de Lewy. Recientemente, varios genes han sido asociados con esta enfermedad, sin embargo su fisiopatología no es clara y los modelos celulares podrían consolidarse como una herramienta importante para validar la genómica funcional, así como las vías de señalización en las cuales éstos participan y sus efectos en la home...

  15. [Toxins of Clostridium perfringens].

    Science.gov (United States)

    Morris, W E; Fernández-Miyakawa, M E

    2009-01-01

    Clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. It is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. However, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. In human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in Papua-New Guinea tribes. The renewed interest existing nowadays in the study of C. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled science to have deeper knowledge of the biology and pathology of these bacteria. In this review, we discuss and update the principal aspects of C. perfringens intestinal pathology, in terms of the toxins with major medical relevance at present. PMID:20085190

  16. THE C2 OXIDATIVE PHOTOSYNTHETIC CARBON CYCLE.

    Science.gov (United States)

    Tolbert, N. E.

    1997-06-01

    The C2 oxidative photosynthetic carbon cycle plus the C3 reductive photosynthetic carbon cycle coexist. Both are initiated by Rubisco, use about equal amounts of energy, must regenerate RuBP, and result in exchanges of CO2 and O2 to establish rates of net photosynthesis, CO2 and O2 compensation points, and the ratio of CO2 and O2 in the atmosphere. These concepts evolved from research on O2 inhibition, glycolate metabolism, leaf peroxisomes, photorespiration, 18O2/16O2 exchange, CO2 concentrating processes, and a requirement for the oxygenase activity of Rubisco. Nearly 80 years of research on these topics are unified under the one process of photosynthetic carbon metabolism and its self-regulation. PMID:15012254

  17. Targeted Toxins in Brain Tumor Therapy

    Directory of Open Access Journals (Sweden)

    Walter A. Hall

    2010-11-01

    Full Text Available 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.

  18. Scorpion toxins prefer salt solutions.

    Science.gov (United States)

    Nikouee, Azadeh; Khabiri, Morteza; Cwiklik, Lukasz

    2015-11-01

    There is a wide variety of ion channel types with various types of blockers, making research in this field very complicated. To reduce this complexity, it is essential to study ion channels and their blockers independently. Scorpion toxins, a major class of blockers, are charged short peptides with high affinities for potassium channels. Their high selectivity and inhibitory properties make them an important pharmacological tool for treating autoimmune or nervous system disorders. Scorpion toxins typically have highly charged surfaces and-like other proteins-an intrinsic ability to bind ions (Friedman J Phys Chem B 115(29):9213-9223, 1996; Baldwin Biophys J 71(4):2056-2063, 1996; Vrbka et al. Proc Natl Acad Sci USA 103(42):15440-15444, 2006a; Vrbka et al. J Phys Chem B 110(13):7036-43, 2006b). Thus, their effects on potassium channels are usually investigated in various ionic solutions. In this work, computer simulations of protein structures were performed to analyze the structural properties of the key residues (i.e., those that are presumably involved in contact with the surfaces of the ion channels) of 12 scorpion toxins. The presence of the two most physiologically abundant cations, Na(+) and K(+), was considered. The results indicated that the ion-binding properties of the toxin residues vary. Overall, all of the investigated toxins had more stable structures in ionic solutions than in water. We found that both the number and length of elements in the secondary structure varied depending on the ionic solution used (i.e., in the presence of NaCl or KCl). This study revealed that the ionic solution should be chosen carefully before performing experiments on these toxins. Similarly, the influence of these ions should be taken into consideration in the design of toxin-based pharmaceuticals. PMID:26475740

  19. 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.

  20. Botulinum Toxin Injections: A Treatment for Muscle Spasms

    Science.gov (United States)

    ... A Treatment for Muscle Spasms What is botulinum toxin? Botulinum toxin is a protein that helps stop muscle ... won't have any harmful effects from the toxin. Botulinum toxin has been used safely for a number ...

  1. 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.

  2. The European corn borer (Ostrinia nubilalis, Hbn.), its susceptibility to the Bt-toxin Cry1F, its pheromone races and its gene flow in Europe in view of an insect resistance management

    OpenAIRE

    Gaspers, Claudia

    2010-01-01

    One of the most promising and effective method for a control of the maize pest, Ostrinia nubilalis (European corn borer; „ECB“), is the cultivation of Bt-maize, which expresses lepidoteran-specific toxins. For a sustainable use of this technology an insect resistance management (IRM) is required to delay resistance development of the target pest, because in the past insects have developed resistance to all major classes of chemical insecticides. As a consequence of the increasing cultivation ...

  3. Sodium Channel Inhibiting Marine Toxins

    Science.gov (United States)

    Llewellyn, Lyndon E.

    Saxitoxin (STX), tetrodotoxin (TTX) and their many chemical relatives are part of our daily lives. From killing people who eat seafood containing these toxins, to being valuable research tools unveiling the invisible structures of their pharmacological receptor, their global impact is beyond measure. The pharmacological receptor for these toxins is the voltage-gated sodium channel which transports Na ions between the exterior to the interior of cells. The two structurally divergent families of STX and TTX analogues bind at the same location on these Na channels to stop the flow of ions. This can affect nerves, muscles and biological senses of most animals. It is through these and other toxins that we have developed much of our fundamental understanding of the Na channel and its part in generating action potentials in excitable cells.

  4. Entry of Shiga toxin into cells

    DEFF Research Database (Denmark)

    Sandvig, Kirsten; van Deurs, Bo

    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...

  5. Clostridium difficile and C. difficile Toxin Testing

    Science.gov (United States)

    ... be limited. Home Visit Global Sites Search Help? Clostridium difficile and C. difficile Toxin Testing Share this page: ... C. diff; C diff antigen; GDH Formal name: Clostridium difficile Culture; C. difficile Toxin, A and B; C. ...

  6. Proteomics analysis of toxins-producing dinoflagellates and toxins-contaminated marine organisms

    OpenAIRE

    蒋析文; Jiang, Xiwen

    2012-01-01

    Paralytic shellfish poisoning (PSP) and ciguatera fish poisoning (CFP) are the two major contributors to illnesses caused by dinoflagellate toxins. Paralytic shellfish poisoning toxins (PSTs) are produced by dinoflagellates in the genera Alexandrium, Gymnodinium, and Pyrodinium while ciguatera fish poisoning toxins, such as ciguatoxins (CTXs), are originated from benthic toxic dinoflagellates (Gambierdiscus, Prorocentrum, Ostreopsis, and Coolia species). These toxins are responsible for human...

  7. Atmospheric studies of C2 white dwarfs

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, S.R.

    1989-01-01

    Model atmosphere and line formation calculations for the delta nu = + 1 Swan bands of the C2 molecule are presented for seven white dwarfs and are compared to high resolution optical spectra. Limits on the C-12 to C-13 ratio are computed for highly pressure broadened lines and are used to analyze the observed spectra for any sign of absorption by the (C-12)(C-13) molecule. The metal abundances in cool white dwarf atmospheres and the usefulness of the determination of the C-12 to C-13 ratio are discussed. The line center shift and the pressure broadening are used to determine a value for the van der Waals interaction constant, C6. This is done using a detailed line modelling program which explicitly includes approximately 2000 rotational transition lines within the vibrational bands, in conjunction with atmospheric models calculated by the LUCIFER atmosphere modelling program. The isotopic shift of the vibrational and rotational lines is also included in the model to compare the detectability of various C-12 to C-13 ratios. The line models fit the observed spectra with varying degrees of accuracy. One star, WD0548-001, shows an unusually small pressure shift and broadening for the high pressures that the atmospheric model predicts. The results show that only in the hottest stars with the least pressure broadened lines in this study can the isotopic effect be seen. With the data available, the best limit on the C-12 to C-13 ratio is a minimum of 40 for WD0856 + 331. The models show that even for very high signal to noise data, the isotopic shift in the Swan bands in very cool white dwarfs would be difficult to separate from the pressure broadening effects. It is shown that the isotopic ratio is high enough to rule out the possibility that the carbon is a relic from previous CNO burning.

  8. Atmospheric studies of C2 white dwarfs

    International Nuclear Information System (INIS)

    Model atmosphere and line formation calculations for the delta nu = + 1 Swan bands of the C2 molecule are presented for seven white dwarfs and are compared to high resolution optical spectra. Limits on the C-12 to C-13 ratio are computed for highly pressure broadened lines and are used to analyze the observed spectra for any sign of absorption by the (C-12)(C-13) molecule. The metal abundances in cool white dwarf atmospheres and the usefulness of the determination of the C-12 to C-13 ratio are discussed. The line center shift and the pressure broadening are used to determine a value for the van der Waals interaction constant, C6. This is done using a detailed line modelling program which explicitly includes approximately 2000 rotational transition lines within the vibrational bands, in conjunction with atmospheric models calculated by the LUCIFER atmosphere modelling program. The isotopic shift of the vibrational and rotational lines is also included in the model to compare the detectability of various C-12 to C-13 ratios. The line models fit the observed spectra with varying degrees of accuracy. One star, WD0548-001, shows an unusually small pressure shift and broadening for the high pressures that the atmospheric model predicts. The results show that only in the hottest stars with the least pressure broadened lines in this study can the isotopic effect be seen. With the data available, the best limit on the C-12 to C-13 ratio is a minimum of 40 for WD0856 + 331. The models show that even for very high signal to noise data, the isotopic shift in the Swan bands in very cool white dwarfs would be difficult to separate from the pressure broadening effects. It is shown that the isotopic ratio is high enough to rule out the possibility that the carbon is a relic from previous CNO burning

  9. Toxin yet not toxic: Botulinum toxin in dentistry.

    Science.gov (United States)

    Archana, M S

    2016-04-01

    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. PMID:27486290

  10. 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.

  11. Toxin content and cytotoxicity of algal dietary supplements

    International Nuclear Information System (INIS)

    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−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.

  12. Both, toxin A and toxin B, are important in Clostridium difficile infection

    OpenAIRE

    Kuehne, Sarah A; Cartman, Stephen T; Minton, Nigel P.

    2011-01-01

    The bacterium Clostridium difficile is the leading cause of healthcare associated diarrhoea in the developed world and thus presents a major financial burden. The main virulence factors of C. difficile are two large toxins, A and B. Over the years there has been some debate over the respective roles and importance of these two toxins. To address this, we recently constructed stable toxin mutants of C. difficile and found that they were virulent if either toxin A or toxin B was functional. Thi...

  13. Characterization of the Maf family of polymorphic toxins in pathogenic Neisseria species

    Directory of Open Access Journals (Sweden)

    Anne Jamet

    2015-03-01

    Full Text Available In addition to harmless commensal species, Neisseria genus encompasses two pathogenic species, N. meningitidis (the meningococcus and N. gonorrhoeae (the gonococcus, which are responsible for meningitis and genital tract infections, respectively. Since the publication of the first Neisseria genome in 2000, the presence of several genomic islands (GI comprising maf genes has been intriguing. These GIs account for approximately 2% of the genome of the pathogenic Neisseria species and the function of the proteins encoded by maf genes remained unknown. We showed that maf genes encode a functional toxin-immunity system where MafB is a toxin neutralized by an immunity protein named MafI. A strain can harbor several MafB/MafI modules with distinct toxic activities. MafB toxins are polymorphic toxins with a conserved N-terminal region and a variable C-terminal region. MafB N-terminal regions consist of a signal peptide and a domain named DUF1020 that is only found in the genus Neisseria. MafB C-terminal regions are highly polymorphic and encode toxic activities. We evidenced the presence of MafB in the culture supernatant of meningococcal cells and we observed a competitive advantage for a strain overexpressing a MafB toxin. Therefore, we characterized a highly variable family of toxin-immunity modules found in multiple loci in pathogenic Neisseria species.

  14. Overview of Scorpion Species from China and Their Toxins

    OpenAIRE

    Zhijian Cao; Zhiyong Di; Yingliang Wu; Wenxin Li

    2014-01-01

    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 ...

  15. D型产气荚膜梭菌ε毒素基因表达及其免疫保护作用的初步研究%Expression of Epsilon-toxin Gene of Clostridium perfringens Type D and its Primary Immunological Protective Function

    Institute of Scientific and Technical Information of China (English)

    王光华; 蔺国珍; 郑福英; 曹小安; 宫晓炜; 周继章; 邱昌庆

    2012-01-01

    利用PCR技术,从D型产气荚膜梭菌标准株(C60-2)染色体DNA中扩增出ε毒素基因.该基因产物大小为906bp,序列分析结果表明,与GenBank报道的产气荚膜梭菌参考菌株ε毒素基因序列同源性大于99.将扩增的ε毒素基因定向克隆到原核表达载体pET32a中,得到重组质粒pET32a-ETX,将重组质粒转化大肠杆菌BL21 (DE3) plys中,经IPTG诱导后,SDS PAGE分析可见大小为54 ku的特异条带;经Western blotting和ELISA检测结果表明,表达的ε毒素能与抗天然ε毒素抗体发生特异性反应,说明ε毒素蛋白具有较好的反应原性.将表达的ε毒素蛋白用0.4%的甲醛溶液制成类毒素疫苗,免疫小鼠后,具有一定的保护力,这表明该重组菌株有望成为产气荚膜梭菌基因工程类毒素疫苗的候选菌株.%Epsilon-toxin (etoxin) gene was amplified from chromosomal DNA of Clostridium perfringens type D (C60-2) by polymerase chain reaction (PCR) .and a 906 bp epsilon toxin gene fragment was obtained. Sequence analysis indicated that the homology of the nucleotide sequence of the strain to those other reference strains was more than 99%. The expression plas-mid pET32a-ETX was constructed by inserting the epsilon toxin gene into the prokaryotic expression vector pET32a. The plas-mid pET32a-ETX was transformated into E. coli BL21 (DE3) plys and the recombinant strain BL21 (pET32a-ETX) was obtained. Then,the transformants were induced to express with IPTG. The specific 54 ku protein was detected by SDS-PAGE and the immunogenicity of the expressed epsilon toxin was confirmed by Western blotting and ELISA. The obtained recombinant protein was transformed into epsilon toxoid vaccine by adding 0. I% formaldehyde into epsilon toxin. The protective immune response was proved after the mice was immunized with epsilon toxoid vaccine. The results showed that the recombinan-ted strain BL21(pET32a-ETX) could be as a candidate of epsilon toxoid vaccine to provide

  16. 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.

  17. 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.

  18. Food irradiation and bacterial toxins

    International Nuclear Information System (INIS)

    The authors' findings indicate that irradiation confers no advantage over heat processing in respect of bacterial toxins (clostridium botulinum, neurotoxin A and staphylococcal enterotoxin A). It follows that irradiation at doses less than the ACINF recommended upper limit of 10 kGy could not be used to improve the ambient temperature shelf life on non-acid foods. (author)

  19. Double-antibody radioimmunoassay for staphylococcal enterotoxin C2

    International Nuclear Information System (INIS)

    A sensitive double-antibody radioimmunoassay for staphylococcal enterotoxin C2 is described. The assay procedure employs anti-rabbit gamma globulin, prepared in goats, to precipitate the antigen-antibody complex of enterotoxin C2 and anti-enterotoxin C2. The test is sensitive to 100 pg of enterotoxin

  20. Mutations in human C2CD3 cause skeletal dysplasia and provide new insights into phenotypic and cellular consequences of altered C2CD3 function.

    Science.gov (United States)

    Cortés, Claudio R; McInerney-Leo, Aideen M; Vogel, Ida; Rondón Galeano, Maria C; Leo, Paul J; Harris, Jessica E; Anderson, Lisa K; Keith, Patricia A; Brown, Matthew A; Ramsing, Mette; Duncan, Emma L; Zankl, Andreas; Wicking, Carol

    2016-01-01

    Ciliopathies are a group of genetic disorders caused by defective assembly or dysfunction of the primary cilium, a microtubule-based cellular organelle that plays a key role in developmental signalling. Ciliopathies are clinically grouped in a large number of overlapping disorders, including the orofaciodigital syndromes (OFDS), the short rib polydactyly syndromes and Jeune asphyxiating thoracic dystrophy. Recently, mutations in the gene encoding the centriolar protein C2CD3 have been described in two families with a new sub-type of OFDS (OFD14), with microcephaly and cerebral malformations. Here we describe a third family with novel compound heterozygous C2CD3 mutations in two fetuses with a different clinical presentation, dominated by skeletal dysplasia with no microcephaly. Analysis of fibroblast cultures derived from one of these fetuses revealed a reduced ability to form cilia, consistent with previous studies in C2cd3-mutant mouse and chicken cells. More detailed analyses support a role for C2CD3 in basal body maturation; but in contrast to previous mouse studies the normal recruitment of the distal appendage protein CEP164 suggests that this protein is not sufficient for efficient basal body maturation and subsequent axonemal extension in a C2CD3-defective background. PMID:27094867

  1. 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.

  2. 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. PMID:25740779

  3. 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

    OpenAIRE

    Mohammad Kargar; Peyman Dianati; Maryam Homayoon; Houshang Jamali

    2013-01-01

    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 resear...

  4. 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.

  5. A toxin-antitoxin module in Bacillus subtilis can both mitigate and amplify effects of lethal stress.

    Directory of Open Access Journals (Sweden)

    Xiangli Wu

    Full Text Available BACKGROUND: Bacterial type-2 (protein-protein toxin-antitoxin (TA modules are two-gene operons that are thought to participate in the response to stress. Previous work with Escherichia coli has led to a debate in which some investigators conclude that the modules protect from stress, while others argue that they amplify lethal stress and lead to programmed cell death. To avoid ambiguity arising from the presence of multiple TA modules in E. coli, the effect of the sole type-2 toxin-antitoxin module of Bacillus subtilis was examined for several types of lethal stress. METHODOLOGY/PRINCIPAL FINDINGS: Genetic knockout of the toxin gene, ndoA (ydcE, conferred protection to lethal stressors that included kanamycin, moxifloxacin, hydrogen peroxide, and UV irradiation. However, at low doses of UV irradiation the ndoA deficiency increased lethality. Indeed, gradually increasing UV dose with the ndoA mutant revealed a crossover response--from the mutant being more sensitive than wild-type cells to being less sensitive. For high temperature and nutrient starvation, the toxin deficiency rendered cells hypersensitive. The ndoA deficiency also reduced sporulation frequency, indicating a role for toxin-antitoxin modules in this developmental process. In the case of lethal antimicrobial treatment, deletion of the toxin eliminated a surge in hydrogen peroxide accumulation observed in wild-type cells. CONCLUSIONS: A single toxin-antitoxin module can mediate two opposing effects of stress, one that lowers lethality and another that raises it. Protective effects are thought to arise from toxin-mediated inhibition of translation based on published work. The enhanced, stress-mediated killing probably involves toxin-dependent accumulation of reactive oxygen species, since a deficiency in the NdoA toxin suppressed peroxide accumulation following antimicrobial treatment. The type and perhaps the level of stress appear to be important for determining whether this toxin

  6. Molecular composition of the 16S toxin produced by a Clostridium botulinum type D strain, 1873.

    Science.gov (United States)

    Nakajima, H; Inoue, K; Ikeda, T; Fujinaga, Y; Sunagawa, H; Takeshi, K; Ohyama, T; Watanabe, T; Inoue, K; Oguma, K

    1998-01-01

    The 16S toxin was purified from a Clostridium botulinum type D strain 1873 (D-1873). Furthermore, the entire nucleotide sequences of the genes coding for the 16S toxin were determined. It became clear that the purified D-1873 16S toxin consists of neurotoxin, nontoxic nonhemagglutinin (NTNH), and hemagglutinin (HA), and that HA consists of four subcomponents, HA1, HA2, HA3a, and HA3b, the same as type D strain CB16 (D-CB16) 16S toxin. The nucleotide sequences of the nontoxic components of these two strains were also found to be identical except for several bases. However, the culture supernatant and the purified 16S toxin of D-1873 showed little HA activity, unlike D-CB16, though the fractions successively eluted after the D-1873 16S toxin peak from an SP-Toyopearl 650S column showed a low level of HA activity. The main difference between D-1873 and D-CB16 HA molecules was the mobility of the HA1 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Therefore it was presumed that the loss of HA activity of D-1873 16S toxin might be caused by the differences of processing HA after the translation. PMID:9802560

  7. Mutually Unbiasedness between Maximally Entangled Bases and Unextendible Maximally Entangled Systems in C2C^{2k}

    Science.gov (United States)

    Zhang, Jun; Nan, Hua; Tao, Yuan-Hong; Fei, Shao-Ming

    2016-02-01

    The mutually unbiasedness between a maximally entangled basis (MEB) and an unextendible maximally entangled system (UMES) in the bipartite system C2C^{2k} (k>1) are introduced and discussed first in this paper. Then two mutually unbiased pairs of a maximally entangled basis and an unextendible maximally entangled system are constructed; lastly, explicit constructions are obtained for mutually unbiased MEB and UMES in C2⊗ C4 and C2⊗ C8, respectively.

  8. DVB-C2: Ready-PlugFest-Go

    OpenAIRE

    Hasse, Philipp; Schaaf, Christoph

    2013-01-01

    DVB-C2 is the 3rd member of the DVB family of second generation transmission systems. Both the DVB-C2 Technical Specification (EN 302 769) [1] and the DVB-C2 Implementation Guidelines (TS 102 991) [2] have been approved by ETSI in 2011 in its current version. The two major building blocks of DVB-C2 are the LDPC (Low Density Parity Check) FEC (Forward Error Correction) Code and the OFDM (Orthogonal Frequency Division Multiplex) modulation scheme. Using DVB-C2, cable operators will be able to i...

  9. Genetic mapping of Bt-toxin binding proteins in a Cry1A-toxin resistant strain of diamondback moth Plutella xylostella.

    Science.gov (United States)

    Baxter, Simon W; Zhao, Jian-Zhou; Shelton, Anthony M; Vogel, Heiko; Heckel, David G

    2008-02-01

    A major mechanism of resistance to Bacillus thuringiensis (Bt) toxins in Lepidoptera is a reduction of toxin binding to sites in the midgut membrane. Genetic studies of three different species have shown that mutations in a candidate Bt receptor, a 12-cadherin-domain protein, confer Cry1A toxin resistance. Despite a similar resistance profile in a fourth lepidopteran species, Plutella xylostella, we have previously shown that the cadherin orthologue maps to a different linkage group (LG8) than Cry1Ac resistance (LG22). Here we tested the hypothesis that mutations in other genes encoding candidate Bt-binding targets could be responsible for Bt resistance, by mapping eight aminopeptidases, an alkaline phosphatase (ALP), an intestinal mucin, and a P252 glycoprotein with respect to the 29 AFLP marked linkage groups in a P. xylostella cross segregating for Cry1Ac resistance. A homologue of the Caenorhabditis elegans Bt resistance gene bre-2 was also mapped. None of the genes analysed were on the same chromosome containing the Cry1Ac resistance locus, eliminating them as candidate resistance genes in the parental resistant strain SC1. Although this finding excludes cis-acting mutations in these genes as causing resistance in this strain, one or more of the expressed proteins may still bind Cry1Ac toxin, and post-translational modifications could affect this binding and thereby exert a trans-acting effect on resistance. PMID:18207074

  10. Recombinant Actinobacillus actinomycetemcomitans Cytolethal Distending Toxin Proteins Are Required To Interact To Inhibit Human Cell Cycle Progression and To Stimulate Human Leukocyte Cytokine Synthesis

    OpenAIRE

    Akifusa, Sumio; Poole, Stephen; Lewthwaite, Jo; Henderson, Brian; Nair, Sean P

    2001-01-01

    It has recently been discovered that Actinobacillus actinomycetemcomitans, an oral bacterium causing periodontitis, produces cytolethal distending toxin (CDT), a cell cycle-modulating toxin that has three protein subunits: CdtA, CdtB, and CdtC. In this study, we have cloned and expressed each toxin gene from A. actinomycetemcomitans in Escherichia coli and purified the recombinant Cdt proteins to homogeneity. Individual Cdt proteins failed to induce cell cycle arrest of the human epithelial c...

  11. 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.

  12. 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. PMID:22069558

  13. 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.

  14. The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation

    International Nuclear Information System (INIS)

    The crystal structure of C2b has been determined at 1.8 Å resolution, which reveals the arrangement of its three complement control protein (CCP) modules. A model for complement component C2 is presented and its conformational changes during the C3-convertase formation are also discussed. The second component of complement (C2) is a multi-domain serine protease that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The formation of these convertases requires the Mg2+-dependent binding of C2 to C4b and the subsequent cleavage of C2 by C1s or MASP2, respectively. The crystal structure of full-length C2 is not yet available, although the structure of its C-terminal catalytic segment C2a has been determined. The crystal structure of the N-terminal segment C2b of C2 determined to 1.8 Å resolution presented here reveals the arrangement of its three CCP domains. The domains are arranged differently compared with most other CCP-domain assemblies, but their arrangement is similar to that found in the Ba part of the full-length factor B structure. The crystal structures of C2a, C2b and full-length factor B are used to generate a model for C2 and a discussion of the domain association and possible interactions with C4b during formation of the C4b–C2 complex is presented. The results of this study also suggest that upon cleavage by C1s, C2a domains undergo conformational rotation while bound to C4b and the released C2b domains may remain folded together similar to as observed in the intact protein

  15. The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Vengadesan [Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Xu, Yuanyuan [Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Macon, Kevin [Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Volanakis, John E. [Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Narayana, Sthanam V. L., E-mail: narayana@uab.edu [Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)

    2009-03-01

    The crystal structure of C2b has been determined at 1.8 Å resolution, which reveals the arrangement of its three complement control protein (CCP) modules. A model for complement component C2 is presented and its conformational changes during the C3-convertase formation are also discussed. The second component of complement (C2) is a multi-domain serine protease that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The formation of these convertases requires the Mg{sup 2+}-dependent binding of C2 to C4b and the subsequent cleavage of C2 by C1s or MASP2, respectively. The crystal structure of full-length C2 is not yet available, although the structure of its C-terminal catalytic segment C2a has been determined. The crystal structure of the N-terminal segment C2b of C2 determined to 1.8 Å resolution presented here reveals the arrangement of its three CCP domains. The domains are arranged differently compared with most other CCP-domain assemblies, but their arrangement is similar to that found in the Ba part of the full-length factor B structure. The crystal structures of C2a, C2b and full-length factor B are used to generate a model for C2 and a discussion of the domain association and possible interactions with C4b during formation of the C4b–C2 complex is presented. The results of this study also suggest that upon cleavage by C1s, C2a domains undergo conformational rotation while bound to C4b and the released C2b domains may remain folded together similar to as observed in the intact protein.

  16. 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.

  17. Intravital imaging of Bacillus thuringiensis Cry1A toxin binding sites in the midgut of silkworm.

    Science.gov (United States)

    Li, Na; Wang, Jing; Han, Heyou; Huang, Liang; Shao, Feng; Li, Xuepu

    2014-02-15

    Identification of the resistance mechanism of insects against Bacillus thuringiensis Cry1A toxin is becoming an increasingly challenging task. This fact highlights the need for establishing new methods to further explore the molecular interactions of Cry1A toxin with insects and the receptor-binding region of Cry1A toxins for their wider application as biopesticides and a gene source for gene-modified crops. In this contribution, a quantum dot-based near-infrared fluorescence imaging method has been applied for direct dynamic tracking of the specific binding of Cry1A toxins, CrylAa and CrylAc, to the midgut tissue of silkworm. The in vitro fluorescence imaging displayed the higher binding specificity of CrylAa-QD probes compared to CrylAc-QD to the brush border membrane vesicles of midgut from silkworm. The in vivo imaging demonstrated that more CrylAa-QDs binding to silkworm midgut could be effectively and distinctly monitored in living silkworms. Furthermore, frozen section analysis clearly indicated the broader receptor-binding region of Cry1Aa compared to that of Cry1Ac in the midgut part. These observations suggest that the insecticidal activity of Cry toxins may depend on the receptor-binding sites, and this scatheless and visual near-infrared fluorescence imaging could provide a new avenue to study the resistance mechanism to maintain the insecticidal activity of B. thuringiensis toxins. PMID:24252542

  18. Immunological cross-reactivity in the absence of DNA homology between Pseudomonas toxin A and diphtheria toxin.

    OpenAIRE

    Sadoff, J C; Buck, G A; Iglewski, B H; Bjorn, M J; Groman, N B

    1982-01-01

    The immunodominant determinant of Pseudomonas toxin A was shown to cross-react with a normally inaccessible determinant in fragment A of diphtheria toxin. Trypsin-treated diphtheria toxin and fragment A of diphtheria toxin inhibited binding of toxin A antibody to whole toxin A, whereas whole diphtheria toxin did not inhibit this reaction. However, even at the lowest stringency no hybridization was detected between diphtheria tox probe and Pseudomonas aeruginosa DNA.

  19. [Botulinum toxin type A in headache treatment : Established and experimental indications].

    Science.gov (United States)

    Gaul, C; Holle-Lee, D; Straube, A

    2016-08-01

    In recent years botulinum toxin type A has been used increasingly more in the treatment of specific headache disorders. Especially regarding chronic migraine with and without combined medication overuse, convincing randomized studies have proven the efficacy of this treatment option and have led to approval for this indication. Regarding other headache entities, such as episodic migraine, tension-type headache, trigeminal autonomic cephalalgia (TAC), neuralgic, neuropathic and myofascial pain, currently available scientific data on the efficacy of botulinum toxin type A are scarce and often ambiguous. The exact underlying mechanisms of the influence of botulinum toxin type A on the pathophysiology of headache are not completely clear but an influence on the release of calcitonin gene-related peptide (CGRP) seems to play a crucial role. This article summarizes the most important studies as well as experiences of treatment with botulinum toxin type A regarding different headache entities. PMID:27300190

  20. Orphan nuclear receptor Nur77 is required for the differentiation of C6 glioma cells induced by cholera toxin

    Institute of Scientific and Technical Information of China (English)

    Dong XU; Yi-jun HUANG; Yan LI; Wei YIN; Guang-mei YAN

    2009-01-01

    Aim: To investigate a possible regulator gene involved in the cholera toxin-induced differentiation of rat C6 glioma cells. Methods: The global changes in the mRNA expression pattern induced by cholera toxin were analyzed using gene chip microarray. The selected gene was then silenced by RNA interference or overexpressed with an ORF plasmid to determine its necessity in this process. Results: Nur77, a member of the orphan nuclear receptor family (NR4A), was markedly up-regulated during the process of differentiation. Furthermore, RNAi of nur77 attenuated the induction effect of cholera toxin on C6 cells, whereas overexpression of nur77 led to similarly differentiated behavior, including morphologic and biomarker changes, as well as cell cycle arrest. Conclusion: Nur77 participated actively and essentially as an important regulator in the cholera toxin-induced differentiation of C6 cells.

  1. Why do we study animal toxins?

    Science.gov (United States)

    Zhang, Yun

    2015-07-18

    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

  2. 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.

  3. Detection of E. coli O157:H7 and Shigella dysenteriae toxins in clinical samples by PCR-ELISA

    Directory of Open Access Journals (Sweden)

    Jafar Amani

    2015-06-01

    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 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.

  4. Structure-function discrepancy in Clostridium botulinum C3 toxin for its rational prioritization as a subunit vaccine.

    Science.gov (United States)

    Prathiviraj, R; Prisilla, A; Chellapandi, P

    2016-06-01

    Clostridium botulinum is anaerobic pathogenic bacterium causing food-born botulism in human and animals by producing botulinum neurotoxins A-H, C2, and C3 cytotoxins. Physiological group III strains (type C and D) of this bacterium are capable of producing C2 and C3 toxins in cattle and avian. Herein, we have revealed the structure-function disparity of C3 toxins from two different C. botulinum type C phage (CboC) and type D phage (CboD) to design avirulent toxins rationally. Structure-function discrepancy of the both toxins was computationally evaluated from their homology models based on the conservation in sequence-structure-function relationships upon covariation and point mutations. It has shown that 8 avirulent mutants were generated from CboC of 34 mutants while 27 avirulent mutants resulted from CboD mutants. No major changes were found in tertiary structure of these toxins; however, some structural variations appeared in the coiled and loop regions. Correlated mutation on the first residue would disorder or revolutionize the hydrogen bonding pattern of the coevolved pairs. It suggested that the residues coupling in the local structural environments were compensated with coevolved pairs so as to preserve a pseudocatalytic function in the avirulent mutants. Avirulent mutants of C3 toxins have shown a stable structure with a common blue print of folding process and also attained a near-native backrub ensemble. Thus, we concluded that selecting the site-directed mutagenesis sites are very important criteria for designing avirulent toxins, in development of rational subunit vaccines, to cattle and avian, but the vaccine specificity can be determined by the C3 toxins of C. botulinum harboring phages. PMID:26239365

  5. Botulinum toxin: Bioweapon & magic drug

    OpenAIRE

    Dhaked, Ram Kumar; Singh, Manglesh Kumar; Singh, Padma; Gupta, Pallavi

    2010-01-01

    Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal p...

  6. Botulinum Toxin in Pediatric Neurology

    OpenAIRE

    Moawad, Eman M. I.; Abdallah, Enas Abdallah Ali

    2015-01-01

    Botulinum neurotoxins are natural molecules produced by anaerobic spore-forming bacteria called Clostradium boltulinum. The toxin has a peculiar mechanism of action by preventing the release of acetylcholine from the presynaptic membrane. Consequently, it has been used in the treatment of various neurological conditions related to muscle hyperactivity and/or spasticity. Also, it has an impact on the autonomic nervous system by acting on smooth muscle, leading to its use in the management of p...

  7. 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.

  8. Emerging high throughput analyses of cyanobacterial toxins and toxic cyanobacteria.

    Science.gov (United States)

    Sivonen, Kaarina

    2008-01-01

    The common occurrence of toxic cyanobacteria causes problems for health of animals and human beings. More research and good monitoring systems are needed to protect water users. It is important to have rapid, reliable and accurate analysis i.e. high throughput methods to identify the toxins as well as toxin producers in the environment. Excellent methods, such as ELISA already exist to analyse cyanobacterial hepatotoxins and saxitoxins, and PPIA for microcystins and nodularins. The LC/MS method can be fast in identifying the toxicants in the samples. Further development of this area should resolve the problems with sampling and sample preparation, which still are the bottlenecks of rapid analyses. In addition, the availability of reliable reference materials and standards should be resolved. Molecular detection methods are now routine in clinical and criminal laboratories and may also become important in environmental diagnostics. One prerequisite for the development of molecular analysis is that pure cultures of the producer organisms are available for identification of the biosynthetic genes responsible for toxin production and for proper testing of the diagnostic methods. Good methods are already available for the microcystin and nodularin-producing cyanobacteria such as conventional PCR, quantitative real-time PCR and microarrays/DNA chips. The DNA-chip technology offers an attractive monitoring system for toxic and non-toxic cyanobacteria. Only with these new technologies (PCR + DNA-chips) will we be able to study toxic cyanobacteria populations in situ and the effects of environmental factors on the occurrence and proliferation of especially toxic cyanobacteria. This is likely to yield important information for mitigation purposes. Further development of these methods should include all cyanobacterial biodiversity, including all toxin producers and primers/probes to detect producers of neurotoxins, cylindrospermopsins etc. (genes are unknown). The on

  9. Immunotoxins, ligand-toxin conjugates and molecular targeting.

    Science.gov (United States)

    Soria, M

    1989-01-01

    Biotechnology provides tools for therapeutic exploitation following advances in the elucidation of protein-to-cell and cell-to-cell interactions. Molecular targeting of bacterial and plant toxins to the desired district of action can be achieved through effector molecules like monoclonal antibodies or protein ligands. Biochemical conjugation of these effectors to SO-6, a single-chain Ribosome Inactivating Protein from Saponaria officinalis, yielded powerful cytotoxic agents that are attractive candidates for therapeutic evaluation. Cloning of the gene for this plant toxin has been achieved. Technologies for expression of protein ligands, such as apolipoproteins or several growth factors, are available in recombinant microorganisms, providing adequate partners for the assembly of targeted chimaeras. Domain engineering of structural and functional regions in effector proteins is now possible and will be carried out with the available technologies to improve existing therapy. PMID:2698471

  10. 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.

  11. Functional Inactivation of Putative Photosynthetic Electron Acceptor Ferredoxin C2 (FdC2 Induces Delayed Heading Date and Decreased Photosynthetic Rate in Rice.

    Directory of Open Access Journals (Sweden)

    Juan Zhao

    Full Text Available Ferredoxin (Fd protein as unique electron acceptor, involved in a variety of fundamental metabolic and signaling processes, which is indispensable for plant growth. The molecular mechanisms of Fd such as regulation of electron partitioning, impact of photosynthetic rate and involvement in the carbon fixing remain elusive in rice. Here we reported a heading date delay and yellowish leaf 1 (hdy1 mutant derived from Japonica rice cultivar "Nipponbare" subjected to EMS treatment. In the paddy field, the hdy1 mutant appeared at a significantly late heading date and had yellow-green leaves during the whole growth stage. Further investigation indicated that the abnormal phenotype of hdy1 was connected with depressed pigment content and photosynthetic rate. Genetic analysis results showed that the hdy1 mutant phenotype was caused by a single recessive nuclear gene mutation. Map-based cloning revealed that OsHDY1 is located on chromosome 3 and encodes an ortholog of the AtFdC2 gene. Complementation and overexpression, transgenic plants exhibited the mutant phenotype including head date, leaf color and the transcription levels of the FdC2 were completely rescued by transformation with OsHDY1. Real-time PCR revealed that the expression product of OsHDY1 was detected in almost all of the organs except root, whereas highest expression levels were observed in seeding new leaves. The lower expression levels of HDY1 and content of iron were detected in hdy1 than WT's. The FdC2::GFP was detected in the chloroplasts of rice. Real-time PCR results showed that the expression of many photosynthetic electron transfer related genes in hdy1 were higher than WT. Our results suggest that OsFdC2 plays an important role in photosynthetic rate and development of heading date by regulating electron transfer and chlorophyll content in rice.

  12. Functional Inactivation of Putative Photosynthetic Electron Acceptor Ferredoxin C2 (FdC2) Induces Delayed Heading Date and Decreased Photosynthetic Rate in Rice

    Science.gov (United States)

    Ruan, Banpu; Kang, Shujing; He, Lei; Zhang, Sen; Dong, Guojun; Hu, Jiang; Zeng, Dali; Zhang, Guangheng; Gao, Zhenyu; Ren, Deyong; Hu, Xingming; Chen, Guang; Guo, Longbiao; Qian, Qian; Zhu, Li

    2015-01-01

    Ferredoxin (Fd) protein as unique electron acceptor, involved in a variety of fundamental metabolic and signaling processes, which is indispensable for plant growth. The molecular mechanisms of Fd such as regulation of electron partitioning, impact of photosynthetic rate and involvement in the carbon fixing remain elusive in rice. Here we reported a heading date delay and yellowish leaf 1 (hdy1) mutant derived from Japonica rice cultivar “Nipponbare” subjected to EMS treatment. In the paddy field, the hdy1 mutant appeared at a significantly late heading date and had yellow-green leaves during the whole growth stage. Further investigation indicated that the abnormal phenotype of hdy1 was connected with depressed pigment content and photosynthetic rate. Genetic analysis results showed that the hdy1 mutant phenotype was caused by a single recessive nuclear gene mutation. Map-based cloning revealed that OsHDY1 is located on chromosome 3 and encodes an ortholog of the AtFdC2 gene. Complementation and overexpression, transgenic plants exhibited the mutant phenotype including head date, leaf color and the transcription levels of the FdC2 were completely rescued by transformation with OsHDY1. Real-time PCR revealed that the expression product of OsHDY1 was detected in almost all of the organs except root, whereas highest expression levels were observed in seeding new leaves. The lower expression levels of HDY1 and content of iron were detected in hdy1 than WT’s. The FdC2::GFP was detected in the chloroplasts of rice. Real-time PCR results showed that the expression of many photosynthetic electron transfer related genes in hdy1 were higher than WT. Our results suggest that OsFdC2 plays an important role in photosynthetic rate and development of heading date by regulating electron transfer and chlorophyll content in rice. PMID:26598971

  13. New binding site on common molecular scaffold provides HERG channel specificity of scorpion toxin BeKm-1

    DEFF Research Database (Denmark)

    Korolkova, Yuliya V; Bocharov, Eduard V; Angelo, Kamilla;

    2002-01-01

    The scorpion toxin BeKm-1 is unique among a variety of known short scorpion toxins affecting potassium channels in its selective action on ether-a-go-go-related gene (ERG)-type channels. BeKm-1 shares the common molecular scaffold with other short scorpion toxins. The toxin spatial structure...... resolved by NMR consists of a short alpha-helix and a triple-stranded antiparallel beta-sheet. By toxin mutagenesis study we identified the residues that are important for the binding of BeKm-1 to the human ERG K+ (HERG) channel. The most critical residues (Tyr-11, Lys-18, Arg-20, Lys-23) are located in...

  14. Truncation in the tcdC region of the Clostridium difficile PathLoc of clinical isolates does not predict increased biological activity of Toxin B or Toxin A

    Directory of Open Access Journals (Sweden)

    Levett Paul N

    2009-06-01

    Full Text Available Abstract Background The increased severity of disease associated with the NAP1 strain of Clostridium difficile has been attributed to mutations to the tcdC gene which codes for a negative regulator of toxin production. To assess the role of hyper-production of Toxins A and B in clinical isolates of Clostridium difficile, two NAP1-related and five NAP1 non-related strains were compared. Methods Sequencing was performed on tcdC, tcdR, and tcdE to determine if there were differences that might account for hyper-production of Toxin A and Toxin B in NAP1-related strains. Biological activity of Toxin B was evaluated using the HFF cell CPE assay and Toxin A biological activity was assessed using the Caco-2 Trans-membrane resistance assay. Results Our results confirm that Toxin A and Toxin B production in NAP1-related strains and ATCC 43255 occurs earlier in the exponential growth phase compared to most NAP1-nonrelated clinical isolates. Despite the hyper-production observed in ATCC 43255 it had no mutations in tcdC, tcdR or tcdE. Analysis of the other clinical isolates indicated that the kinetics and ultimate final concentration of Toxin A and B did not correlate with the presence or lack of alterations in tcdC, tcdR or tcdE. Conclusion Our data do not support a direct role for alterations in the tcdC gene as a predictor of hyperproduction of Toxin A and B in NAP1-related strains.

  15. Methane Conversion to C2 Hydrocarbons Using Glow Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    HU Miao; CHEN Jierong

    2007-01-01

    The infrared emission spectra of methane, H', CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the time and conditions of methane decomposition and C2 hydrocarbons formation were different. Methane conversion rate increased with the increase in the current and decrease in the amount of methane. Furthermore, an examination of the reaction mechanisms revealed that free radicals played an important role in the chain reaction.

  16. 26 CFR 1.1402(c)-2 - Public office.

    Science.gov (United States)

    2010-04-01

    ... respect to the functions of a public office of a State or a political subdivision thereof in any period in... 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...

  17. Toxin content and cytotoxicity of algal dietary supplements.

    Science.gov (United States)

    Heussner, A H; Mazija, L; Fastner, J; Dietrich, D R

    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(-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. PMID:23064102

  18. [Use of botulinum toxin in strabismus].

    Science.gov (United States)

    Wabbels, B

    2016-07-01

    Botulinum toxin can be a useful tool for treating acute sixth nerve palsy and excessive eye deviations due to unstable Graves' disease, when surgery is not yet possible. The diagnostic injection for estimation of possible postoperative double vision also makes sense. In convergence spasms, periocular botulinum toxin injections can be a therapeutic option. Botulinum toxin is not a first line option in infantile esotropia without binocularity or in adult horizontal strabismus. Side effects include ptosis and vertical deviations. PMID:27369733

  19. Quantitative microtiter cytotoxicity assay for Shigella toxin.

    OpenAIRE

    Gentry, M. K.; Dalrymple, J M

    1980-01-01

    The cytotoxic activity of Shigella dysenteriae 1 was assayed by exposing HeLa cells in microtiter cultures to dilutions of toxin. Exposure to toxin caused either failure of cells in suspension to attach or detachment of cells from established monolayers. Estimates of toxin potency were made by staining residual cells with crystal violet and visually inspecting the stained plates. Quantitation of the cytotoxic effect was made possible by eluting and spectrophotometrically measuring the stain. ...

  20. Application of Botulinum Toxin in Pain Management

    OpenAIRE

    Sim, Woo Seog

    2011-01-01

    Botulinum toxin has been used for the treatment of many clinical disorders by producing temporary skeletal muscle relaxation. In pain management, botulinum toxin has demonstrated an analgesic effect by reducing muscular hyperactivity, but recent studies suggest this neurotoxin could have direct analgesic mechanisms different from its neuromuscular actions. At the moment, botulinum toxin is widely investigated and used in many painful diseases such as myofascial syndrome, headaches, arthritis,...

  1. Cholera toxin-like toxin released by Salmonella species in the presence of mitomycin C.

    OpenAIRE

    Molina, N C; Peterson, J W

    1980-01-01

    Several serotypes of Salmonella were shown to release increased amounts of a cholera toxin-like toxin during culture in vitro with mitomycin C (MTC). Filter-sterilized culture supernatants containing the toxin caused elongation of Chinese hamster ovary cells, which could be blocked by heating the supernatants at 100 degrees C for 15 min or by adding mixed gangliosides or monospecific cholera antitoxin. When MTC was not added to the Salmonella cultures, little or no toxin was detected in crude...

  2. Synthesis and Biology of Cyclic Imine Toxins, An Emerging Class of Potent, Globally Distributed Marine Toxins

    OpenAIRE

    Stivala, Craig E.; Benoit, Evelyne; Araoz, Romulo; Servent, Denis; Novikov, Alexei; Molgó, Jordi; Zakarian, Armen

    2015-01-01

    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 accumulat...

  3. Protein Translocation by Bacterial Toxin Channels: A Comparison of Diphtheria Toxin and Colicin Ia

    OpenAIRE

    Wu, Zhengyan; Jakes, Karen S.; Samelson-Jones, Ben S.; Lai, Bing; Zhao, Gang; London, Erwin; Finkelstein, Alan

    2006-01-01

    Regions of both colicin Ia and diphtheria toxin N-terminal to the channel-forming domains can be translocated across planar phospholipid bilayer membranes. In this article we show that the translocation pathway of diphtheria toxin allows much larger molecules to be translocated than does the translocation pathway of colicin Ia. In particular, the folded A chain of diphtheria toxin is readily translocated by that toxin but is not translocated by colicin Ia. This difference cannot be attributed...

  4. Clostridium perfringens type A and type A and β2 toxin associated with enterotoxemia in a 5-week-old goat

    OpenAIRE

    Dray, Tammy

    2004-01-01

    Postmortem examination of a Boer buck kid that died peracutely revealed diffusely congested, edematous bowel. Clostridium perfringens Type A was isolated. Some isolates carried the gene for β2 toxin, suggesting a role for β2 toxin in caprine enterotoxemia, a common cause of death in growing kids.

  5. Distribution of putative virulence genes and antimicrobial drug resistance in Vibrio harveyi

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Mendez, D.; Anto, C.

    environments for understanding the distribution of putative virulence genes and antimicrobial drug resistance. The putative genes targeted for PCR detection included four reversible toxin (Rtx)/hemolysin genes, a gene encoding homologue of Vibrio cholerae...

  6. Botulinum Toxin; Bioterror and Biomedicinal Agent

    Directory of Open Access Journals (Sweden)

    Jiri Patocka

    2006-04-01

    Full Text Available Botulinum toxin is a group of seven homologous, highly poisonous proteins isolated fromfermentation of the anaerobic bacterium Clostridium botulinum, which naturally occurs in soiland can grow on many meats and vegetables. Botulinum toxin causes neuromuscular disordercalled botulism, which is a potentially lethal disease. There are three types of botulism: Food,wound, and infant botulism. It can lead to death unless appropriate therapy is done. Due to theseverity and potency of botulinum toxin, its importance as a biological weapon is of majorconcern to public health officials. Nevertheless, botulinum toxin is also medicament.

  7. Shiga Toxin (Stx) Classification, Structure, and Function

    OpenAIRE

    Melton-Celsa, Angela R.

    2014-01-01

    Shiga toxin (Stx) is one of the most potent bacterial toxins known. Stx is found in Shigella dysenteriae 1 and in some serogroups of Escherichia coli (called Stx1 in E. coli). In addition to or instead of Stx1, some E. coli strains produce a second type of Stx, Stx2, that has the same mode of action as Stx/Stx1 but that is antigenically distinct. Because subtypes of each toxin have been identified, the prototype toxin for each group is now designated Stx1a or Stx2a. The Stxs consist of two ma...

  8. Characterization of an RTX-Like Toxin and an Alpha-2-Macroglobulin in Pantoea stewartii subsp. stewartii, Causal Agent of Stewart's Wilt of Sweet Corn

    OpenAIRE

    Williams, Kayla Marie

    2014-01-01

    Pantoea stewartii subsp. stewartii DC283, the causal agent of Stewart's wilt, is an important bacterial pathogen of sweet corn. P. stewartii colonizes the apoplastic space and xylem tissue, resulting in characteristic water-soaked (WS) lesions and wilting. A gene encoding a putative RTX-like toxin, rtx2, has been identified in P. stewartii. RTX toxins belong to the pore-forming toxin family and have lytic properties in animal systems. Little is known about the role of RTX toxins in plant path...

  9. 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.

  10. Botulinum toxin: The Midas touch.

    Science.gov (United States)

    Shilpa, P S; Kaul, Rachna; Sultana, Nishat; Bhat, Suraksha

    2014-01-01

    Botulinum Toxin (BT) is a natural molecule produced during growth and autolysis of bacterium called Clostridium botulinum. Use of BT for cosmetic purposes has gained popularity over past two decades, and recently, other therapeutic uses of BT has been extensively studied. BT is considered as a minimally invasive agent that can be used in the treatment of various orofacial disorders and improving the quality of life in such patients. The objective of this article is to review the nature, mechanism of action of BT, and its application in various head and neck diseases. PMID:24678189

  11. 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,...

  12. Clostridial Glucosylating Toxins Enter Cells via Clathrin-Mediated Endocytosis

    OpenAIRE

    Papatheodorou, Panagiotis; Zamboglou, Constantinos; Genisyuerek, Selda; Guttenberg, Gregor; Aktories, Klaus

    2010-01-01

    Clostridium difficile toxin A (TcdA) and toxin B (TcdB), C. sordellii lethal toxin (TcsL) and C. novyi α-toxin (TcnA) are important pathogenicity factors, which represent the family of the clostridial glucosylating toxins (CGTs). Toxin A and B are associated with antibiotic-associated diarrhea and pseudomembraneous colitis. Lethal toxin is involved in toxic shock syndrome after abortion and α-toxin in gas gangrene development. CGTs enter cells via receptor-mediated endocytosis and require an ...

  13. Transcriptional Regulation of Cytosolic Sulfotransferase 1C2 by Vitamin D Receptor in LS180 Human Colorectal Adenocarcinoma Cells.

    Science.gov (United States)

    Barrett, Kathleen G; Fang, Hailin; Kocarek, Thomas A; Runge-Morris, Melissa

    2016-08-01

    The factors that regulate expression of genes in the 1C family of human cytosolic sulfotransferases (SULT1C) are not well understood. In a recent study evaluating the effects of a panel of transcription factor activators on SULT1C family member expression in LS180 human colorectal adenocarcinoma cells, we found that SULT1C2 expression was significantly increased by 1α,25-dihydroxyvitamin D3 (VitD3) treatment. The objective of our current study was to identify the mechanism responsible for VitD3-mediated activation of SULT1C2 transcription. VitD3 treatment of LS180 cells activated transcription of a transfected luciferase reporter plasmid that contained ∼5 kilobase pairs (kbp) of the SULT1C2 gene, which included 402 nucleotides (nt) of the noncoding exon 1, all of intron 1, and 21 nt of exon 2. Although computational analysis of the VitD3-responsive region of the SULT1C2 gene identified a pregnane X receptor (PXR)-binding site within exon 1, the transfected 5 kbp SULT1C2 reporter was not activated by treatment with rifampicin, a prototypical PXR agonist. However, deletion or mutation of the predicted PXR-binding site abolished VitD3-mediated SULT1C2 transcriptional activation, identifying the site as a functional vitamin D response element (VDRE). We further demonstrated that vitamin D receptor (VDR) can interact directly with the SULT1C2 VDRE sequence using an enzyme-linked immunosorbent assay-based transcription factor binding assay. In conclusion, VitD3-inducible SULT1C2 transcription is mediated through a VDRE in exon 1. These results suggest a role for SULT1C2 in VitD3-regulated physiologic processes in human intestine. PMID:27130351

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

    International Nuclear Information System (INIS)

    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 Ca2+ 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 P212121, 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

  15. 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.

  16. 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, ...

  17. The Ins and Outs of Anthrax Toxin.

    Science.gov (United States)

    Friebe, Sarah; van der Goot, F Gisou; Bürgi, Jérôme

    2016-03-01

    Anthrax is a severe, although rather rare, infectious disease that is caused by the Gram-positive, spore-forming bacterium Bacillus anthracis. The infectious form is the spore and the major virulence factors of the bacterium are its poly-γ-D-glutamic acid capsule and the tripartite anthrax toxin. The discovery of the anthrax toxin receptors in the early 2000s has allowed in-depth studies on the mechanisms of anthrax toxin cellular entry and translocation from the endocytic compartment to the cytoplasm. The toxin generally hijacks the endocytic pathway of CMG2 and TEM8, the two anthrax toxin receptors, in order to reach the endosomes. From there, the pore-forming subunit of the toxin inserts into endosomal membranes and enables translocation of the two catalytic subunits. Insertion of the pore-forming unit preferentially occurs in intraluminal vesicles rather than the limiting membrane of the endosome, leading to the translocation of the enzymatic subunits in the lumen of these vesicles. This has important consequences that will be discussed. Ultimately, the toxins reach the cytosol where they act on their respective targets. Target modification has severe consequences on cell behavior, in particular on cells of the immune system, allowing the spread of the bacterium, in severe cases leading to host death. Here we will review the literature on anthrax disease with a focus on the structure of the toxin, how it enters cells and its immunological effects. PMID:26978402

  18. 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...

  19. Precise manipulation of the Clostridium difficile chromosome reveals a lack of association between the tcdC genotype and toxin production.

    Science.gov (United States)

    Cartman, Stephen T; Kelly, Michelle L; Heeg, Daniela; Heap, John T; Minton, Nigel P

    2012-07-01

    Clostridium difficile causes a potentially fatal diarrheal disease through the production of its principal virulence factors, toxin A and toxin B. The tcdC gene is thought to encode a negative regulator of toxin production. Therefore, increased toxin production, and hence increased virulence, is often inferred in strains with an aberrant tcdC genotype. This report describes the first allele exchange system for precise genetic manipulation of C. difficile, using the codA gene of Escherichia coli as a heterologous counterselection marker. It was used to systematically restore the Δ117 frameshift mutation and the 18-nucleotide deletion that occur naturally in the tcdC gene of C. difficile R20291 (PCR ribotype 027). In addition, the naturally intact tcdC gene of C. difficile 630 (PCR ribotype 012) was deleted and then subsequently restored with a silent nucleotide substitution, or "watermark," so the resulting strain was distinguishable from the wild type. Intriguingly, there was no association between the tcdC genotype and toxin production in either C. difficile R20291 or C. difficile 630. Therefore, an aberrant tcdC genotype does not provide a broadly applicable rationale for the perceived notion that PCR ribotype 027 strains are "high-level" toxin producers. This may well explain why several studies have reported that an aberrant tcdC gene does not predict increased toxin production or, indeed, increased virulence. PMID:22522680

  20. Cloning and sequencing of the C-terminal domain gene of Clostridium difficile toxin B%艰难梭菌细胞毒素B功能区的克隆及序列分析

    Institute of Scientific and Technical Information of China (English)

    刘红升; 张清华; 蒋知新

    2007-01-01

    目的 克隆艰难梭菌(Clostridium difficile,C.d)细胞毒素B羧基末端功能区(CDB3)基因,并对其进行测序及生物信息学分析.方法 利用PCR技术扩增CDB3基因,并将其定向插入pET-22b(+)载体中,以DNA自动分析仪进行序列测定,并以生物信息学软件分析其生物学特性.结果 成功克隆了艰难梭菌CDB3基因,经测序表明与GenBank中分布的Clostridium difficile VPI10463的ToxinB3基因序列完全一致.DNAstar软件预测其蛋白质的相对分子量(Mr)约为71.3 kD,并显示出良好的抗原性.结论 研究获得了序列正确的CDB3基因,为其重组表达及其相关研究奠定了良好基础.

  1. Lifetime of C2Cl4- ions produced by nondissociative electron attachment to C2Cl4

    International Nuclear Information System (INIS)

    The lifetimes of long-lived C2Cl4- ions formed by Rydberg electron transfer in K(np)/C2Cl4 collisions are investigated using a Penning ion trap. Measurements at high n, n≥30, show that low-energy electron attachment to C2Cl4 leads to the production of C2Cl4- ions with a broad range of lifetimes that extends up to at least 1 ms. This is attributed to capture by molecules in different initial vibrational states. At low n, internal-to-translational energy transfer in postattachment interactions between the product K+ and C2Cl4- ions becomes important and leads to a substantial increase in ion lifetimes

  2. Application of a Chimeric Protein Construct having Enterotoxin B and Toxic Shock Syndrome Toxin Domains of S. aureus in Immunodiagnostics

    OpenAIRE

    Shylaja, R.; Thakasi, Devi Kalyan Kumar; H.S. Murali; Reddy, K. Prakash Narayana; Batra, H. V.

    2012-01-01

    Staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin-1 are the super antigens responsible for diseases such as staphylococcal food poisoning and toxic shock syndrome. At low serum concentrations, SEB can trigger toxic shock, profound hypotension and multi organ failure and hence is recognized as biowarfare molecule. In this study, a multidomain fusion protein (r-TE) was generated with specificity for SEB and toxic shock syndrome toxin (Tsst-1). The fusion gene comprising the cons...

  3. Brown spider dermonecrotic toxin directly induces nephrotoxicity

    International Nuclear Information System (INIS)

    Brown spider (Loxosceles genus) venom can induce dermonecrotic lesions at the bite site and systemic manifestations including fever, vomiting, convulsions, disseminated intravascular coagulation, hemolytic anemia and acute renal failure. The venom is composed of a mixture of proteins with several molecules biochemically and biologically well characterized. The mechanism by which the venom induces renal damage is unknown. By using mice exposed to Loxosceles intermedia recombinant dermonecrotic toxin (LiRecDT), we showed direct induction of renal injuries. Microscopic analysis of renal biopsies from dermonecrotic toxin-treated mice showed histological alterations including glomerular edema and tubular necrosis. Hyalinization of tubules with deposition of proteinaceous material in the tubule lumen, tubule epithelial cell vacuoles, tubular edema and epithelial cell lysis was also observed. Leukocytic infiltration was neither observed in the glomerulus nor the tubules. Renal vessels showed no sign of inflammatory response. Additionally, biochemical analyses showed such toxin-induced changes in renal function as urine alkalinization, hematuria and azotemia with elevation of blood urea nitrogen levels. Immunofluorescence with dermonecrotic toxin antibodies and confocal microscopy analysis showed deposition and direct binding of this toxin to renal intrinsic structures. By immunoblotting with a hyperimmune dermonecrotic toxin antiserum on renal lysates from toxin-treated mice, we detected a positive signal at the region of 33-35 kDa, which strengthens the idea that renal failure is directly induced by dermonecrotic toxin. Immunofluorescence reaction with dermonecrotic toxin antibodies revealed deposition and binding of this toxin directly in MDCK epithelial cells in culture. Similarly, dermonecrotic toxin treatment caused morphological alterations of MDCK cells including cytoplasmic vacuoles, blebs, evoked impaired spreading and detached cells from each other and from

  4. The toxin component of targeted anti-tumor toxins determines their efficacy increase by saponins.

    Science.gov (United States)

    Weng, Alexander; Thakur, Mayank; Beceren-Braun, Figen; Bachran, Diana; Bachran, Christopher; Riese, Sebastian B; Jenett-Siems, Kristina; Gilabert-Oriol, Roger; Melzig, Matthias F; Fuchs, Hendrik

    2012-06-01

    Tumor-targeting protein toxins are composed of a toxic enzyme coupled to a specific cell binding domain that targets cancer-associated antigens. The anti-tumor treatment by targeted toxins is accompanied by dose-limiting side effects. The future prospects of targeted toxins for therapeutic use in humans will be determined by reduce side effects. Certain plant secondary metabolites (saponins) were shown to increase the efficacy of a particular epidermal growth factor receptor (EGFR)-targeted toxin, paralleled by a tremendous decrease of side effects. This study was conducted in order to investigate the effects of substituting different toxin moieties fused to an EGF ligand binding domain on the augmentative ability of saponins for each against therapeutic potential of the saponin-mediated efficacy increase for different anti-tumor toxins targeting the EGFR. We designed several EGFR-targeted toxins varying in the toxic moiety. Each targeted toxin was used in combination with a purified saponin (SA1641), isolated from the ornamental plant Gypsophila paniculata L. SA1641 was characterized and the SA1641-mediated efficacy increase was investigated on EGFR-transfected NIH-3T3 cells. We observed a high dependency of the SA1641-mediated efficacy increase on the nature of toxin used for the construction of the targeted toxin, indicating high specificity. Structural alignments revealed a high homology between saporin and dianthin-30, the two toxic moieties that benefit most from the combination with SA1641. We further demonstrate that SA1641 did not influence the plasma membrane permeability, indicating an intracellular interaction of SA1641 and the toxin components of targeted toxins. Surface plasmon resonance measurements point to a transient binding of SA1641 to the toxin components of targeted toxins. PMID:22309811

  5. Interplay between toxin transport and flotillin localization

    DEFF Research Database (Denmark)

    Pust, Sascha; Dyve, Anne Berit; Torgersen, Maria L; van Deurs, Bo; Sandvig, Kirsten

    2010-01-01

    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......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...

  6. 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.

  7. 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. PMID:17607049

  8. Bidirectional effect of Wnt signaling antagonist DKK1 on the modulation of anthrax toxin uptake.

    Science.gov (United States)

    Qian, LiLi; Cai, ChangZu; Yuan, PengFei; Jeong, Sun-Young; Yang, XiaoZhou; Dealmeida, Venita; Ernst, James; Costa, Michael; Cohen, Stanley N; Wei, WenSheng

    2014-05-01

    LRP6, a co-receptor for the morphogen Wnt, aids endocytosis of anthrax complexes. Here we report that Dickkopf1 (DKK1) protein, a secreted LRP6 ligand and antagonist, is also a modulator of anthrax toxin sensitivity. shRNA-mediated gene silencing or TALEN-mediated gene knockout of DKK1 reduced sensitivity of cells to PA-dependent hybrid toxins. However, unlike the solely inhibitory effect on Wnt signaling, the effects of DKK1 overexpression on anthrax toxicity were bidirectional, depending on its endogenous expression and cell context. Fluorescence microscopy and biochemical analyses showed that DKK1 facilitates internalization of anthrax toxins and their receptors, an event mediated by DKK1-LRP6-Kremen2 complex. Monoclonal antibodies against DKK1 provided dose-dependent protection to macrophages from killing by anthrax lethal toxin (LT). Our discovery that DKK1 forms ternary structure with LRP6 and Kremen2 in promoting PA-mediated toxin internalization provides a paradigm for bacterial exploitation of mechanisms that host cells use to internalize signaling proteins. PMID:24671437

  9. Recombinant production of bacterial toxins and their derivatives in the methylotrophic yeast Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Gurkan Cemal

    2005-12-01

    Full Text Available Abstract The methylotrophic yeast Pichia pastoris is a popular heterologous expression host for the recombinant production of a variety of prokaryotic and eukaryotic proteins. The rapid emergence of P. pastoris as a robust heterologous expression host was facilitated by the ease with which it can be manipulated and propagated, which is comparable to that of Escherichia coli and Saccharomyces cerevisiae. P. pastoris offers further advantages such as the tightly-regulated alcohol oxidase promoter that is particularly suitable for heterologous expression of foreign genes. While recombinant production of bacterial toxins and their derivatives is highly desirable, attempts at their heterologous expression using the traditional E. coli expression system can be problematic due to the formation of inclusion bodies that often severely limit the final yields of biologically active products. However, recent literature now suggests that P. pastoris may be an attractive alternative host for the heterologous production of bacterial toxins, such as those from the genera Bacillus, Clostridium, and Corynebacterium, as well as their more complex derivatives. Here, we review the recombinant production of bacterial toxins and their derivatives in P. pastoris with special emphasis on their potential clinical applications. Considering that de novo design and construction of synthetic toxin genes have often been necessary to achieve optimal heterologous expression in P. pastoris, we also present general guidelines to this end based on our experience with the P. pastoris expression of the Bacillus thuringiensis Cyt2Aa1 toxin.

  10. Characterization of a novel toxin-antitoxin module, VapBC, encoded by Leptospira interrogans chromosome

    Institute of Scientific and Technical Information of China (English)

    Yi Xuan ZHANG; Xiao Kui GUO; Chuan WU; Bo BI; Shuang Xi REN; Chun Fu WU; Guo Ping ZHAO

    2004-01-01

    Comparative genomic analysis of the coding sequences (CDSs) of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid sequences and operon organizations. Expression of single vapC gene in Escherichia coli resulted in inhibition of bacterial growth,whereas co-expression of vapBC restored the growth effectively. This phenotype is typical for three other characterized toxin-antitoxin systems of bacteria, i.e., mazEF[1], relBE[2] and chpIK[3]. The VapC proteins of bacteria and a thermophilic archeae, Solfolobus tokodaii, form a structurally distinguished group of toxin different from the other known toxins of bacteria. Phylogenetic analysis of both toxins and antitoxins of all categories indicated that although toxins were evolved from divergent sources and may or may not follow their speciation paths (as indicated by their 16s RNA sequences), co-evolution with their antitoxins was obvious.

  11. Characterization of a novel toxin-antitoxin module, VapBC, encoded by Leptospira interrogans chromosome.

    Science.gov (United States)

    Zhang, Yi Xuan; Li, Juan; Guo, Xiao Kui; Wu, Chuan; Bi, Bo; Ren, Shuang Xi; Wu, Chun Fu; Zhao, Guo Ping

    2004-06-01

    Comparative genomic analysis of the coding sequences (CDSs) of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid sequences and operon organizations. Expression of single vapC gene in Escherichia coli resulted in inhibition of bacterial growth, whereas co-expression of vapBC restored the growth effectively. This phenotype is typical for three other characterized toxin-antitoxin systems of bacteria, i.e., mazEF, relBE and chpIK. The VapC proteins of bacteria and a thermophilic archeae, Solfolobus tokodaii, form a structurally distinguished group of toxin different from the other known toxins of bacteria. Phylogenetic analysis of both toxins and antitoxins of all categories indicated that although toxins were evolved from divergent sources and may or may not follow their speciation paths (as indicated by their 16s RNA sequences), co-evolution with their antitoxins was obvious. PMID:15225414

  12. Location of the Bombyx mori aminopeptidase N type 1 binding site on Bacillus thuringiensis Cry1Aa toxin.

    Science.gov (United States)

    Atsumi, Shogo; Mizuno, Eri; Hara, Hirotaka; Nakanishi, Kazuko; Kitami, Madoka; Miura, Nami; Tabunoki, Hiroko; Watanabe, Ayako; Sato, Ryoichi

    2005-07-01

    We analyzed the binding site on Cry1Aa toxin for the Cry1Aa receptor in Bombyx mori, 115-kDa aminopeptidase N type 1 (BmAPN1) (K. Nakanishi, K. Yaoi, Y. Nagino, H. Hara, M. Kitami, S. Atsumi, N. Miura, and R. Sato, FEBS Lett. 519:215-220, 2002), by using monoclonal antibodies (MAbs) that block binding between the binding site and the receptor. First, we produced a series of MAbs against Cry1Aa and obtained two MAbs, MAbs 2C2 and 1B10, that were capable of blocking the binding between Cry1Aa and BmAPN1 (blocking MAbs). The epitope of the Fab fragments of MAb 2C2 overlapped the BmAPN1 binding site, whereas the epitope of the Fab fragments of MAb 1B10 did not overlap but was located close to the binding site. Using three approaches for epitope mapping, we identified two candidate epitopes for the blocking MAbs on Cry1Aa. We constructed two Cry1Aa toxin mutants by substituting a cysteine on the toxin surface at each of the two candidate epitopes, and the small blocking molecule N-(9-acridinyl)maleimide (NAM) was introduced at each cysteine substitution to determine the true epitope. The Cry1Aa mutant with NAM bound to Cys582 did not bind either of the two blocking MAbs, suggesting that the true epitope for each of the blocking MAbs was located at the site containing Val582, which also consisted of 508STLRVN513 and 582VFTLSAHV589. These results indicated that the BmAPN1 binding site overlapped part of the region blocked by MAb 2C2 that was close to but excluded the actual epitope of MAb 2C2 on domain III of Cry1Aa toxin. We also discuss another area on Cry1Aa toxin as a new candidate site for BmAPN1 binding. PMID:16000811

  13. The occurrence of Photorhabdus-like toxin complexes in Bacillus thuringiensis

    Science.gov (United States)

    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 w...

  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. Myostatin Stimulates, Not Inihibits, C2C12 Myoblast Proliferation

    OpenAIRE

    Rodgers, Buel D.; Wiedeback, Benjamin D.; Hoversten, Knut E.; Jackson, Melissa F; Walker, Ryan G.; Thompson, Thomas B.

    2014-01-01

    The immortal C2C12 cell line originates from dystrophic mouse thigh muscle and has been used to study the endocrine control of muscle cell growth, development, and function, including those actions regulated by myostatin. Previous studies suggest that high concentrations of recombinant myostatin generated in bacteria inhibit C2C12 proliferation and differentiation. Recombinant myostatin generated in eukaryotic systems similarly inhibits the proliferation of primary myosatellite cells, but con...

  16. Nonrigid spherical real analytic hypersurfaces in C^2

    OpenAIRE

    Merker, Joel

    2009-01-01

    A Levi nondegenerate real analytic hypersurface M of C^2 represented in local coordinates (z, w) in C^2 by a complex defining equation of the form w = Theta (z, \\bar z, \\bar w) which satisfies an appropriate reality condition, is spherical if and only if its complex graphing function Theta satisfies an explicitly written sixth-order polynomial complex partial differential equation. In the rigid case (known before), this system simplifies considerably, but in the general nonrigid case, its com...

  17. Roles of Anthrax Toxin Receptor 2 in Anthrax Toxin Membrane Insertion and Pore Formation

    Directory of Open Access Journals (Sweden)

    Jianjun Sun

    2016-01-01

    Full Text Available Interaction between bacterial toxins and cellular surface receptors is an important component of the host-pathogen interaction. Anthrax toxin protective antigen (PA binds to the cell surface receptor, enters the cell through receptor-mediated endocytosis, and forms a pore on the endosomal membrane that translocates toxin enzymes into the cytosol of the host cell. As the major receptor for anthrax toxin in vivo, anthrax toxin receptor 2 (ANTXR2 plays an essential role in anthrax toxin action by providing the toxin with a high-affinity binding anchor on the cell membrane and a path of entry into the host cell. ANTXR2 also acts as a molecular clamp by shifting the pH threshold of PA pore formation to a more acidic pH range, which prevents premature pore formation at neutral pH before the toxin reaches the designated intracellular location. Most recent studies have suggested that the disulfide bond in the immunoglobulin (Ig-like domain of ANTXR2 plays an essential role in anthrax toxin action. Here we will review the roles of ANTXR2 in anthrax toxin action, with an emphasis on newly updated knowledge.

  18. Acid-base actuation of [c2]daisy chains.

    Science.gov (United States)

    Fang, Lei; Hmadeh, Mohamad; Wu, Jishan; Olson, Mark A; Spruell, Jason M; Trabolsi, Ali; Yang, Ying-Wei; Elhabiri, Mourad; Albrecht-Gary, Anne-Marie; Stoddart, J Fraser

    2009-05-27

    A versatile synthetic strategy, which was conceived and employed to prepare doubly threaded, bistable [c2]daisy chain compounds, is described. Propargyl and 1-pentenyl groups have been grafted onto the stoppers of [c2]daisy chain molecules obtained using a template-directed synthetic protocol. Such [c2]daisy chain molecules undergo reversible extension and contraction upon treatment with acid and base, respectively. The dialkyne-functionalized [c2]daisy chain (AA) was subjected to an [AA+BB] type polymerization with an appropriate diazide (BB) to afford a linear, mechanically interlocked, main-chain polymer. The macromolecular properties of this polymer were characterized by chronocoulometry, size exclusion chromatography, and static light-scattering analysis. The acid-base switching properties of both the monomers and the polymer have been studied in solution, using (1)H NMR spectroscopy, UV/vis absorption spectroscopy, and cyclic voltammetry. The experimental results demonstrate that the functionalized [c2]daisy chains, along with their polymeric derivatives, undergo quantitative, efficient, and fully reversible switching processes in solution. Kinetics measurements demonstrate that the acid/base-promoted extension/contraction movements of the polymeric [c2]daisy chain are actually faster than those of its monomeric counterpart. These observations open the door to correlated molecular motions and to changes in material properties. PMID:19419175

  19. Characterization of an acute muscle contraction model using cultured C2C12 myotubes.

    Directory of Open Access Journals (Sweden)

    Yasuko Manabe

    Full Text Available A cultured C2C12 myotube contraction system was examined for application as a model for acute contraction-induced phenotypes of skeletal muscle. C2C12 myotubes seeded into 4-well rectangular plates were placed in a contraction system equipped with a carbon electrode at each end. The myotubes were stimulated with electric pulses of 50 V at 1 Hz for 3 ms at 997-ms intervals. Approximately 80% of the myotubes were observed to contract microscopically, and the contractions lasted for at least 3 h with electrical stimulation. Calcium ion (Ca²⁺ transient evoked by the electric pulses was detected fluorescently with Fluo-8. Phosphorylation of protein kinase B/Akt (Akt, 5' AMP-activated protein kinase (AMPK, p38 mitogen-activated protein kinase (p38, and c-Jun NH2-terminal kinase (JNK1/2, which are intracellular signaling proteins typically activated in exercised/contracted skeletal muscle, was observed in the electrically stimulated C2C12 myotubes. The contractions induced by the electric pulses increased glucose uptake and depleted glycogen in the C2C12 myotubes. C2C12 myotubes that differentiated after exogenous gene transfection by a lipofection or an electroporation method retained their normal contractile ability by electrical stimulation. These findings show that our C2C12 cell contraction system reproduces the muscle phenotypes that arise invivo (exercise, in situ (hindlimb muscles in an anesthetized animal, and invitro (dissected muscle tissues in incubation buffer by acute muscle contraction, demonstrating that the system is applicable for the analysis of intracellular events evoked by acute muscle contraction.

  20. Detection and Toxin Typing of Clostridium perfringens in Formalin-Fixed, Paraffin-Embedded Tissue Samples by PCR▿

    OpenAIRE

    Wu, Josephine; Zhang, Wandi; Xie, Boxun; Wu, Maoxin; Tong, Xiaodi; Kalpoe, Jayant; Zhang, David

    2008-01-01

    Since current microbiology methods are not suitable to detect Clostridium perfringens in formalin-fixed, paraffin-embedded tissue samples, we developed a PCR assay to detect toxin-encoding genes and the 16S rRNA gene of C. perfringens. We successfully detected and genotyped C. perfringens in tissue sections from two autopsy cases.

  1. 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

  2. Characterization of neutralizing monoclonal antibodies directed against tetanus toxin fragment C.

    Science.gov (United States)

    Yousefi, Mehdi; Tahmasebi, Fathollah; Younesi, Vahid; Razavi, Alireza; Khoshnoodi, Jalal; Bayat, Ali Ahmad; Abbasi, Ebrahim; Rabbani, Hodjatallah; Jeddi-Tehrani, Mahmood; Shokri, Fazel

    2014-01-01

    Clostridium tetani causes a life-threatening infectious disease by production of tetanus neurotoxin (TeNT), a 150 kDa molecule composed of light (LC) and heavy chain (HC) polypeptides. The TeNT HC contains an N-terminal domain critical for LC translocation and a C-terminal toxin receptor-binding domain known as fragment C. Despite extensive investigations on epitope specificity of anti-TeNT antibodies, the immunodominant neutralizing epitopes of the toxin are poorly defined. This study describes the generation and characterization of four monoclonal antibodies (MAb) specific for TeNT. The characteristics of each MAb were explored in terms of isotype, specificity, affinity, and immuno-globulin heavy chain variable region (IGHV) gene usage using ELISA, Western blotting, and sequencing techniques. The toxin neutralizing activity of the MAbs was also investigated using the in vitro GT1b neutralizing assay. The data demonstrated that all MAbs bind to tetanus toxin and toxoid. Sub-fragments binding analysis showed that two MAbs react with fragment C, one with both fragment C and LC, and one with LC. Only the two fragment C-specific MAbs were able to neutralize the toxin. Sequencing of the expressed VH and VL genes revealed rearrangements of various VH and VL gene segments in all hybridoma clones. Clonality of the hybridomas was also confirmed by a competition assay that showed recognition of distinct epitopes by these MAbs. The results suggest the importance of TeNT fragment C in terms of immunogenicity and toxin neutralization activity. PMID:23369087

  3. C2H observations toward the Orion Bar

    Science.gov (United States)

    Nagy, Z.; Ossenkopf, V.; Van der Tak, F. F. S.; Faure, A.; Makai, Z.; Bergin, E. A.

    2015-06-01

    Context. The ethynyl radical (C2H) is one of the first radicals to be detected in the interstellar medium. Its higher rotational transitions have recently become available with the Herschel Space Observatory. Aims: We aim to constrain the physical parameters of the C2H emitting gas toward the Orion Bar. Methods: We analyze the C2H line intensities measured toward the Orion Bar CO+ Peak and Herschel/HIFI maps of C2H, CH, and HCO+ and a NANTEN map of [Ci]. We interpret the observed C2H emission using the combination of Herschel/HIFI and NANTEN data with radiative transfer and PDR models. Results: Five rotational transitions of C2H (from N = 6-5 up to N = 10-9) have been detected in the HIFI frequency range toward the CO+ peak of the Orion Bar. Based on the five detected C2H transitions, a single component rotational diagram analysis gives a rotation temperature of ~64 K and a beam-averaged C2H column density of 4 × 1013 cm-2. The rotational diagram is also consistent with a two-component fit, resulting in rotation temperatures of 43 ± 0.2 K and 123 ± 21 K and in beam-averaged column densities of ~8.3 × 1013 cm-2 and ~2.3 × 1013 cm-2 for the three lower-N and for the three higher-N transitions, respectively. The measured five rotational transitions cannot be explained by any single parameter model. According to a non-LTE model, most of the C2H column density produces the lower-N C2H transitions and traces a warm (Tkin ~ 100-150 K) and dense (n(H2) ~ 105-106 cm-3) gas. A small fraction of the C2H column density is required to reproduce the intensity of the highest-N transitions (N = 9-8 and N = 10-9) originating in a high-density (n(H2) ~5 × 106 cm-3) hot (Tkin ~ 400 K) gas. The total beam-averaged C2H column density in the model is 1014 cm-2. A comparison of the spatial distribution of C2H to those of CH, HCO+, and [Ci] shows the best correlation with CH. Conclusions: Both the non-LTE radiative transfer model and a simple PDR model representing the Orion Bar

  4. Cyanobacterial toxins: risk management for health protection

    International Nuclear Information System (INIS)

    This paper reviews the occurrence and properties of cyanobacterial toxins, with reference to the recognition and management of the human health risks which they may present. Mass populations of toxin-producing cyanobacteria in natural and controlled waterbodies include blooms and scums of planktonic species, and mats and biofilms of benthic species. Toxic cyanobacterial populations have been reported in freshwaters in over 45 countries, and in numerous brackish, coastal, and marine environments. The principal toxigenic genera are listed. Known sources of the families of cyanobacterial toxins (hepato-, neuro-, and cytotoxins, irritants, and gastrointestinal toxins) are briefly discussed. Key procedures in the risk management of cyanobacterial toxins and cells are reviewed, including derivations (where sufficient data are available) of tolerable daily intakes (TDIs) and guideline values (GVs) with reference to the toxins in drinking water, and guideline levels for toxigenic cyanobacteria in bathing waters. Uncertainties and some gaps in knowledge are also discussed, including the importance of exposure media (animal and plant foods), in addition to potable and recreational waters. Finally, we present an outline of steps to develop and implement risk management strategies for cyanobacterial cells and toxins in waterbodies, with recent applications and the integration of Hazard Assessment Critical Control Point (HACCP) principles

  5. Accumulation, Biotransformation, Histopathology and Paralysis in the Pacific Calico Scallop Argopecten ventricosus by the Paralyzing Toxins of the Dinoflagellate Gymnodinium catenatum

    Science.gov (United States)

    Escobedo-Lozano, Amada Y.; Estrada, Norma; Ascencio, Felipe; Contreras, Gerardo; Alonso-Rodriguez, Rosalba

    2012-01-01

    The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2); after hydrolysis, the carbamate toxins (epimers GTX2/3) were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment. PMID:22822356

  6. Recombinant toxin-coregulated pilus A (TcpA) as a candidate subunit cholera vaccine.

    OpenAIRE

    Somayeh Kiaie; Hamid Abtahi; Ghasem Mosayebi; MohammadYosef Alikhani; Iraj Pakzad

    2014-01-01

    Background and Objectives The toxin co-regulated pilus A (TcpA) has been described as a critical pathogenicity factor of Vibrio cholerae. TcpA is a candidate for making subunit vaccine against cholera. The aim of this study was to produce a candidate vaccine by expressing recombinant TcpA in E. coli. Materials and Methods In this study, the toxin co-regulated pilus A gene from EL-Tor, V. cholerae subspecies, was amplified by PCR and sub-cloned into prokaryotic expression vector pGEX4T1. E. co...

  7. Shiga toxin-producing Escherichia coli in beef retail markets from Argentina

    OpenAIRE

    Brusa, Victoria; Aliverti, Virginia; Aliverti, Florencia; Ortega, Emanuel E.; de la Torre, Julian H.; Linares, Luciano H.; Sanz, Marcelo E; Etcheverría, Analía I.; Padola, Nora L.; Galli, Lucía; Peral García, Pilar; Copes, Julio; Leotta, Gerardo A.

    2013-01-01

    Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that cause mild or serious diseases and can lead to people death. This study reports the prevalence and characteristics of STEC O157 and non-O157 in commercial ground beef and environmental samples, including meat table, knife, meat mincing machine, and manipulator hands (n = 450) obtained from 90 retail markets over a nine-month period. The STEC isolates were serotyped and virulence genes as stx (Shiga toxin), rfb O157] (O...

  8. The Enterotoxicity of Clostridium difficile Toxins

    OpenAIRE

    Hanping Feng; Tor Savidge; Xingmin Sun

    2010-01-01

    The major virulence factors of Clostridium difficile infection (CDI) are two large exotoxins A (TcdA) and B (TcdB). However, our understanding of the specific roles of these toxins in CDI is still evolving. It is now accepted that both toxins are enterotoxic and proinflammatory in the human intestine. Both purified TcdA and TcdB are capable of inducing the pathophysiology of CDI, although most studies have focused on TcdA. C. difficile toxins exert a wide array of biological activities by act...

  9. Molecular cloning and expression of epsilon toxin from Clostridium perfringens type D and tests of animal immunization.

    Science.gov (United States)

    Souza, A M; Reis, J K P; Assis, R A; Horta, C C; Siqueira, F F; Facchin, S; Alvarenga, E R; Castro, C S; Salvarani, F M; Silva, R O S; Pires, P S; Contigli, C; Lobato, F C F; Kalapothakis, E

    2010-01-01

    Epsilon toxin produced by Clostridium perfringens types B and D causes enterotoxemia in sheep, goats and calves. Enterotoxemia can cause acute or superacute disease, with sudden death of the affected animal. It provokes huge economic losses when large numbers of livestock are affected. Therapeutic intervention is challenging, because the disease progresses very rapidly. However, it can be prevented by immunization with specific immunogenic vaccines. We cloned the etx gene, encoding epsilon toxin, into vector pET-11a; recombinant epsilon toxin (rec-epsilon) was expressed in inclusion bodies and was used for animal immunization. Serum protection was evaluated and cross-serum neutralization tests were used to characterize the recombinant toxin. To analyze the potency of the toxin (as an antigen), rabbits were immunized with 50, 100 or 200 microg recombinant toxin, using aluminum hydroxide gel as an adjuvant. Titers of 10, 30 and 40 IU/mL were obtained, respectively. These titers were higher than the minimum level required by the European Pharmacopoeia (5 IU/mL) and by the USA Code of Federal Regulation (2 IU/mL). This rec-epsilon is a good candidate for vaccine production against enterotoxemia caused by epsilon toxin of C. perfringens type D. PMID:20198582

  10. Retrograde transport of protein toxins through the Golgi apparatus

    DEFF Research Database (Denmark)

    Sandvig, Kirsten; Skotland, Tore; van Deurs, Bo; Klokk, Tove Irene

    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...

  11. 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.

  12. Binding and uptake of diphtheria toxin by toxin-resistant Chinese hamster ovary and mouse cells.

    OpenAIRE

    Didsbury, J R; Moehring, J M; Moehring, T. J.

    1983-01-01

    We investigated two phenotypically distinct types of diphtheria toxin-resistant mutants of Chinese hamster cells and compared their resistance with that of naturally resistant mouse cells. All are resistant due to a defect in the process of internalization and delivery of toxin to its target in the cytosol, elongation factor 2. By cell hybridization studies, analysis of cross-resistance, and determination of specific binding sites for 125I-labeled diphtheria toxin, we showed that these cell s...

  13. Release of C2 Radicals after the Deep Impact Event

    Science.gov (United States)

    Schulz, R.; Stüwe, J. A.; Erd, C.; Martin, D.; Smit, H.

    We present the results of investigating the coma of comet 9P/Tempel 1 in C2 and continuum, before and after the Deep Impact event of 4 July 2005. A jet-like coma feature was produced by the impact, and its temporal evolution in morphology and brightness has been compared for the dust and gas coma. It shows that the feature remains visible in the dust coma for several days, whereas in the C2 coma it is visible only on the image taken 15.8 hours after the impact and has vanished when the coma was observed again in the following night. The observational evidence strongly supports that the C2 in the feature observed on 4 July 2005 was produced from fresh dust particles released by the outburst and forming an extended source for the production of the C2 radical. This indicates that the disintegration of C2-bearing dust species can directly be observed during the non-steady state conditions present immediately after outbursts and/or nucleus splitting.

  14. Superconductivity in non-centrosymmetric ThCoC2

    International Nuclear Information System (INIS)

    Superconductivity in compounds whose crystal structure lacks inversion symmetry are known to display intriguing properties that deviate from conventional BCS superconducting behavior. Here we report magnetization, resistivity, and heat capacity measurements on polycrystalline samples of ThCoC2, which has been reported to crystallize in the non-centrosymmetric CeNiC2 prototype structure, and show clear evidence of bulk superconductivity in ThCoC2 with a critical temperature of Tc = 2.65 K. From the specific heat data we find a Sommerfeld coefficient of γ = 8.38 mJ mol−1 K−2 and a Debye temperature of ΘD = 449 K. Interestingly the Hc2 superconducting phase diagram displays positive curvature, and the specific heat at low temperature deviates from conventional exponential temperature dependence, which is suggestive of possible unconventional superconducting behavior in ThCoC2, similar to that seen in the isostructural and isoelectronic non-centrosymmetric superconductor LaNiC2. (paper)

  15. 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...... reaction HOCH2CH2OO+NO→CH2OH+CH2O+NO2, which pushes a complex system of partial equilibria towards products. This is a confirmation of the findings of Doughty et al. [3] for a similar system at atmospheric pressure. Under reducing conditions and temperatures above 700K, a significant fraction of the NOx is...... 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 the...

  16. Transcytosis, Antitumor Activity and Toxicity of Staphylococcal Enterotoxin C2 as an Oral Administration Protein Drug

    Science.gov (United States)

    Zhao, Wenbin; Li, Yangyang; Liu, Wenhui; Ding, Ding; Xu, Yingchun; Pan, Liqiang; Chen, Shuqing

    2016-01-01

    Staphylococcal enterotoxin C2 (SEC2) is a classical superantigen (SAg), which can tremendously activate T lymphocytes at very low dosage, thus exerting its powerful antitumor activity. As an intravenous protein drug and a bacterial toxin, SEC2 has some limitations including poor patient compliance and toxic side effects. In this research, we devoted our attention to studying the antitumor activity and toxicity of SEC2 as a potential oral administration protein drug. We proved that His-tagged SEC2 (SEC2-His) could undergo facilitated transcytosis on human colon adenocarcinoma (Caco-2) cells and SEC2-His was detected in the blood of rats after oral administration. Furthermore, oral SEC2-His caused massive cytokine release and immune cell enrichment around tumor tissue, leading to inhibition of tumor growth in vivo. Meanwhile, although SEC2-His was dosed up to 32 mg/kg in mice, no significant toxicity was observed. These data showed that SEC2 can cross the intestinal epithelium in an immunologically integral form, maintaining antitumor activity but with reduced systemic toxicity. Therefore, these results may have implications for developing SEC2 as an oral administration protein drug. PMID:27322320

  17. [Botulinum toxin in disabling dermatological diseases].

    Science.gov (United States)

    Messikh, R; Atallah, L; Aubin, F; Humbert, P

    2009-05-01

    Botulinum toxin could represent nowadays a new treatment modality especially for cutaneous conditions in course of which conventional treatments remain unsuccessful. Besides palmar and plantar hyperhidrosis, botulinum toxin has demonstrated efficacy in different conditions associated with hyperhidrosis, such as dyshidrosis, multiple eccrine hidrocystomas, hidradenitis suppurativa, Frey syndrome, but also in different conditions worsened by hyperhidrosis such as Hailey-Hailey disease, Darier disease, inversed psoriasis, aquagenic palmoplantar keratoderma, pachyonychia congenital. Moreover, different cutaneous conditions associated with sensitive disorders and/or neurological involvements could benefit from botulinum toxin, for example anal fissures, leg ulcers, lichen simplex, notalgia paresthetica, vestibulitis. Endly, a case of cutis laxa was described where the patient was improved by cutaneous injections of botulinum toxin. PMID:19576479

  18. Hemolytic anemia caused by chemicals and toxins

    Science.gov (United States)

    Anemia - hemolytic - caused by chemicals or toxins ... Possible substances that can cause hemolytic anemia include: Anti-malaria drugs (quinine compounds) Arsenic Dapsone Intravenous water infusion (not half-normal saline or normal saline) Metals (chromium/chromates, ...

  19. 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...

  20. 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...

  1. Anticancer potential of animal venoms and toxins.

    Science.gov (United States)

    Gomes, Antony; Bhattacharjee, Pushpak; Mishra, Roshnara; Biswas, Ajoy K; Dasgupta, Subir Chandra; Giri, Biplab

    2010-02-01

    Anticancer drug development from natural resources are ventured throughout the world. Animal venoms and toxins a potential bio resource and a therapeutic tool were known to man for centuries through folk and traditional knowledge. The biodiversity of venoms and toxins made it a unique source of leads and structural templates from which new therapeutic agents may be developed. Venoms of several animal species (snake, scorpion, toad, frog etc) and their active components (protein and non protein toxins, peptides, enzymes, etc) have shown therapeutic potential against cancer. In the present review, the anticancer potential of venoms and toxins from snakes, scorpions, toads and frogs has been discussed. Some of these molecules are in the clinical trials and may find their way towards anticancer drug development in the near future. The implications of combination therapy of natural products in cancer have been discussed. PMID:20455317

  2. Morphology, toxin composition and LSU rDNA phylogeny of Alexandrium minutum (Dinophyceae) from Denmark, with some morphological observations on other European strains

    DEFF Research Database (Denmark)

    Hansen, Gert; Daugbjerg, Niels; Franco, J.M.

    2003-01-01

    . Cells without a pore also dominated field material from Ireland but a small fraction (6%) did have a pore. Many cells had a heavily areolated theca. In the exponential growth phase, the PSP-toxin profile of the Danish strain of A. minutum was dominated by C1 and C2 (up to 70%), whereas GTX2 and 3 made...

  3. Transition probability data for seven band systems of C2

    Science.gov (United States)

    Coo, D. M.; Nicholls, R. W.

    1976-01-01

    Absolute transition-probability parameters are reported for seven band systems of the C2 molecule. These include all the known C2 band systems in the spectral region between 0.2 and 1.2 microns with the exception of the Messerle-Krauss system. To obtain the data, absolute intensities of selected spectral regions were measured behind the incident shock wave in a combustion-driven shock tube containing 85% Ar and 15% C2H2. These measurements were converted into electronic transition moments by a synthetic spectrum analysis. The electronic transition moments were then used to determine extensive tables of the transition-probability parameters for each of the band systems measured.

  4. 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.

  5. Nanoanalysis of the arthropod neuro-toxins

    OpenAIRE

    Nakajima, Terumi

    2006-01-01

    Many kinds of venomous principles modulate physiological responses of mammalian signal transduction systems, on which they act selectively as enhancers, inhibitors or some other kind of effectors. These toxins become useful tools for physiological research. We have employed and characterized paralyzing toxins from the venom of spiders, insects and scorpions with a limited supply. We have developed rapid and sensitive mass spectrometric technology and applied for the identification of these to...

  6. 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. PMID:26958981

  7. 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.

  8. Botulinum Toxin; Bioterror and Biomedicinal Agent

    OpenAIRE

    Jiri Patocka; Kamil Kuca; Daniel Jun

    2006-01-01

    Botulinum toxin is a group of seven homologous, highly poisonous proteins isolated fromfermentation of the anaerobic bacterium Clostridium botulinum, which naturally occurs in soiland can grow on many meats and vegetables. Botulinum toxin causes neuromuscular disordercalled botulism, which is a potentially lethal disease. There are three types of botulism: Food,wound, and infant botulism. It can lead to death unless appropriate therapy is done. Due to theseverity and potency of botulinum toxi...

  9. Normal and Pathologic Concentrations of Uremic Toxins

    OpenAIRE

    Duranton, Flore; Cohen, Gerald; De Smet, Rita; Rodriguez, Mariano; Jankowski, Joachim; Vanholder, Raymond; Argiles, Angel

    2012-01-01

    An updated review of the existing knowledge regarding uremic toxins facilitates the design of experimental studies. We performed a literature search and found 621 articles about uremic toxicity published after a 2003 review of this topic. Eighty-seven records provided serum or blood measurements of one or more solutes in patients with CKD. These records described 32 previously known uremic toxins and 56 newly reported solutes. The articles most frequently reported concentrations of β2-microgl...

  10. Plant Insecticidal Toxins in Ecological Networks

    OpenAIRE

    Sébastien Ibanez; Christiane Gallet; Laurence Després

    2012-01-01

    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-diversificati...

  11. Antibacterial Activity of Ti3C2Tx MXene.

    Science.gov (United States)

    Rasool, Kashif; Helal, Mohamed; Ali, Adnan; Ren, Chang E; Gogotsi, Yury; Mahmoud, Khaled A

    2016-03-22

    MXenes are a family of atomically thin, two-dimensional (2D) transition metal carbides and carbonitrides with many attractive properties. Two-dimensional Ti3C2Tx (MXene) has been recently explored for applications in water desalination/purification membranes. A major success indicator for any water treatment membrane is the resistance to biofouling. To validate this and to understand better the health and environmental impacts of the new 2D carbides, we investigated the antibacterial properties of single- and few-layer Ti3C2Tx MXene flakes in colloidal solution. The antibacterial properties of Ti3C2Tx were tested against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) by using bacterial growth curves based on optical densities (OD) and colonies growth on agar nutritive plates. Ti3C2Tx shows a higher antibacterial efficiency toward both Gram-negative E. coli and Gram-positive B. subtilis compared with graphene oxide (GO), which has been widely reported as an antibacterial agent. Concentration dependent antibacterial activity was observed and more than 98% bacterial cell viability loss was found at 200 μg/mL Ti3C2Tx for both bacterial cells within 4 h of exposure, as confirmed by colony forming unit (CFU) and regrowth curve. Antibacterial mechanism investigation by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with lactate dehydrogenase (LDH) release assay indicated the damage to the cell membrane, which resulted in release of cytoplasmic materials from the bacterial cells. Reactive oxygen species (ROS) dependent and independent stress induction by Ti3C2Tx was investigated in two separate abiotic assays. MXenes are expected to be resistant to biofouling and offer bactericidal properties. PMID:26909865

  12. Preparation of Calibration Standards of N1-H Paralytic Shellfish Toxin Analogues by Large-Scale Culture of Cyanobacterium Anabaena circinalis (TA04

    Directory of Open Access Journals (Sweden)

    Toshiyuki Suzuki

    2011-03-01

    Full Text Available Mouse bioassay is the official testing method to quantify paralytic shellfish toxins (PSTs in bivalves. A number of alternative analytical methods have been reported. Some methods have been evaluated by a single laboratory validation. Among the different types of methods, chemical analyses are capable of identifying and quantifying the toxins, however a shortage of the necessary calibration standards hampers implementation of the chemical analyses in routine monitoring of PSTs in bivalves. In our present study, we studied preparation of major PST analogues as calibrants by large-scale cultivation of toxic freshwater cyanobacteria Anabaena circinalis TA04. The cells were steadily grown in 10 L bottle for 28 days. The primary N1-H toxins, C1/C2, were produced at a concentration of 1.3 ± 0.1 µmol/L. The intracellular and extracellular toxins occupied 80% and 20%, respectively. Over 220 µmol of the toxins was obtained from approximately 200 L of the culture over six months, demonstrating that it is sufficient to prepare saxitoxin analogues. The toxins were chemically converted to six N1-H analogues. Preparation of the analogues was carried out at relatively high yields (50–90%. The results indicate that our preparation method is useful to produce N1-H toxins. In our present study, detailed conditions for preparation of one of the rare N1-H analogues, gonyautoxin-5, were investigated.

  13. Lethal effects of Clostridium perfringens epsilon toxin are potentiated by alpha and perfringolysin-O toxins in a mouse model

    OpenAIRE

    Fernandez-Miyakawa, Mariano E.; Jost, B. Helen; Billington, Stephen J; Uzal, Francisco A.

    2007-01-01

    Epsilon-toxin (ETX) is the most important virulence factor of Clostridium perfringens type D. Two other important toxins, alpha-toxin (CPA) and perfringolysin-O (PFO), are encoded and potentially produced by most C. perfringens type D isolates. The biological effects of these toxins are dissimilar although they are all lethal. Since the possible interaction of these toxins during infection is unknown, the effects of CPA and PFO on the lethal activity of ETX were studied in a mouse model. Mice...

  14. Characterization of toxin from Verocytotoxigenic Ecscherichia coli (VTEC)strains isolated from neonatal calves in India

    Institute of Scientific and Technical Information of China (English)

    Diganta Pan; Ashok Kumar Bhatia; Bhilegaonkar KN

    2009-01-01

    Objective:The present study has characterized dialyzed toxin from non-O157 VTEC E.coli isolates by vero cell toxicity assay and pathogenecity in mice model.Methods:Toxins from non-O157 verocytotoxic Escherichi-a coli isolated from neonatal calves were characterized.Dialyzed toxin from E.coli O26,O111 and O103 sero-types were prepared and characterized by verocell toxicity assay and pathogenicity in mice model.E.coli O157:H7 considered as positive control for this study.Results:Cytopathic effects in vero cell line first roun-ding of vero cells,followed by clumping of cells and finally disintegrated,blackened,shriveled cell line within 16 to 72 hrs.Phenotypic markers such as hind limb paralysis and reddening of tail were prominent in all the toxicated mice.Extensive histopathological study was conducted for multiple organ involvement.Conclusion:Several methods for toxin assay were developed based on biological,immunological and detection of virulence genes related to toxin production but each test has draw back.Therefore,it is likely that future effort will be focused on the development of assay,which is fast,reliable,specific and sensitive methods based on mice model.

  15. “Non-Toxic” Proteins of the Botulinum Toxin Complex Exert In-vivo Toxicity

    Science.gov (United States)

    Miyashita, Shin-Ichiro; Sagane, Yoshimasa; Suzuki, Tomonori; Matsumoto, Takashi; Niwa, Koichi; Watanabe, Toshihiro

    2016-01-01

    The botulinum neurotoxin (BoNT) causes muscle paralysis and is the most potent toxin in nature. BoNT is associated with a complex of auxiliary “Non-Toxic” proteins, which constitute a large-sized toxin complex (L-TC). However, here we report that the “Non-Toxic” complex of serotype D botulinum L-TC, when administered to rats, exerts in-vivo toxicity on small-intestinal villi. Moreover, Serotype C and D of the “Non-Toxic” complex, but not BoNT, induced vacuole-formation in a rat intestinal epithelial cell line (IEC-6), resulting in cell death. Our results suggest that the vacuole was formed in a manner distinct from the mechanism by which Helicobacter pylori vacuolating toxin (VacA) and Vibrio cholerae haemolysin induce vacuolation. We therefore hypothesise that the serotype C and D botulinum toxin complex is a functional hybrid of the neurotoxin and vacuolating toxin (VT) which arose from horizontal gene transfer from an ancestral BoNT-producing bacterium to a hypothetical VT-producing bacterium. PMID:27507612

  16. "Non-Toxic" Proteins of the Botulinum Toxin Complex Exert In-vivo Toxicity.

    Science.gov (United States)

    Miyashita, Shin-Ichiro; Sagane, Yoshimasa; Suzuki, Tomonori; Matsumoto, Takashi; Niwa, Koichi; Watanabe, Toshihiro

    2016-01-01

    The botulinum neurotoxin (BoNT) causes muscle paralysis and is the most potent toxin in nature. BoNT is associated with a complex of auxiliary "Non-Toxic" proteins, which constitute a large-sized toxin complex (L-TC). However, here we report that the "Non-Toxic" complex of serotype D botulinum L-TC, when administered to rats, exerts in-vivo toxicity on small-intestinal villi. Moreover, Serotype C and D of the "Non-Toxic" complex, but not BoNT, induced vacuole-formation in a rat intestinal epithelial cell line (IEC-6), resulting in cell death. Our results suggest that the vacuole was formed in a manner distinct from the mechanism by which Helicobacter pylori vacuolating toxin (VacA) and Vibrio cholerae haemolysin induce vacuolation. We therefore hypothesise that the serotype C and D botulinum toxin complex is a functional hybrid of the neurotoxin and vacuolating toxin (VT) which arose from horizontal gene transfer from an ancestral BoNT-producing bacterium to a hypothetical VT-producing bacterium. PMID:27507612

  17. Cry toxin mode of action in susceptible and resistant Heliothis virescens larvae.

    Science.gov (United States)

    Jurat-Fuentes, Juan Luis; Adang, Michael J

    2006-07-01

    Many pest insect species are effectively controlled by Bacillus thuringiensis (Bt) Cry toxins delivered in plants and biopesticides. Since the insect midgut epithelium contains receptors and other molecules that determine Bt toxicity, characterization of these molecules is necessary for sustained usage of Bt toxins. Studies of Bt susceptible and resistant strains of Heliothis virescens have provided insights into resistance mechanisms and toxin receptors. For example, the first gene identified as involved in high levels of Cry1Ac resistance in H. virescens encodes a cadherin-like protein, a functional Cry1A receptor in Lepidoptera. This manuscript discusses the most updated information on the mode of action of Cry1A toxins obtained from the characterization of resistant mechanisms in H. virescens strains. Our studies are focused on biochemical and molecular comparison of a susceptible and three resistant H. virescens strains to identify alterations that correlate with toxin resistance. Following this approach we have been able to identify an alkaline phosphatase (HvALP) as a potential receptor and tested the utility of this protein as a marker for resistance to Cry1Ac. Comparison of brush border proteomes from susceptible and resistant larvae has allowed us to identify additional molecules directly involved in the toxicity process. PMID:16797583

  18. Intrinsic geometric structure of c = -2 quantum gravity

    Science.gov (United States)

    Ambjørn, J.; Anagnostopoulos, K. N.; Ichihara, T.; Jensen, L.; Kawamoto, N.; Watabiki, Y.; Yotsuji, K.

    1998-04-01

    We couple c = -2 matter to 2-dimensional gravity within the gramework of dynamical triangulations. We use a very fast algorithm, special to the c = -2 case, in order to test scaling of correlation functions defined in terms of geodesic distance and we determine the fractal dimension dH with high accuracy. We find dH = 3.58(4), consistent with a prediction coming from the study of diffusion in the context of Liouville theory, and that the quantum space-time possesses the same fractal properties at all distance scales similarly to the case of pure gravity.

  19. 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.

  20. Affinity chromatography of tetanus toxin, tetanus toxoid, and botulinum A toxin on synaptosomes, and differentiation of their acceptors

    International Nuclear Information System (INIS)

    125I-labelled tetanus toxin and 125I-labelled botulinum A neurotoxin are known to be specifically bound to brain synaptosomes. In order to discriminate between active toxin and inactive admixtures present in the starting material or arising during iodination, synaptosome columns were prepared using bromacetylcellulose and/or kieselgur (Celite) as carriers. Both types of columns adsorb the toxins from low ionic strength medium and release them if the pH and ionic strength are raised. Botulinum toxin was eluted with lower ionic strength than tetanus toxin, and could be freed from nontoxic admixtures. Analysis by affinity chromatography disclosed partially toxoided tetanus toxin in both labelled and unlabelled toxin samples. High concentrations of formaldehyde (0.5%) destroyed both toxicity and affinity to the synaptosomes of tetanus toxin. Low concentrations of formaldehyde (0.05%) yielded a derivative of low toxicity which was still, however less firmly, bound to synaptosomes. Tetanus and botulinum toxin differ by their acceptors. Whereas unlabelled botulinum toxin is unable to compete with labelled tetanus toxin, unlabelled tetanus toxin slightly competes with botulinum toxin. Both labelled toxins display anomalous binding behaviour in that they cannot be displaced completely even with a large excess of unlabelled toxin. (orig.)

  1. Structure and function of C-terminal catalytic region of pasteurella multocida toxin

    International Nuclear Information System (INIS)

    Pasteurella multocida toxin (PMT) is one of virulence factors responsible for the pathogenesis in some Pasteurellosis. We determined the crystal structure of the C-terminal region of PMT (C-PMT), which carries an intracellularly active moiety. The overall structure of C-PMT displays three different domains designated C1, C2 and C3. We found in the C3 domain the Cys-His-Asp catalytic triad that is organized only when the Cys is released from a disulfide bond. The steric alignment of the triad corresponded well to that of papain or other enzymes carrying the Cys-His-Asp triad. Our results demonstrate that PMT is an enzymatic toxin carrying the cysteine-protease like catalytic triad, which is organized only under reducing conditions. (author)

  2. Trigonelline protects the cardiocyte from hydrogen peroxide induced apoptosis in H9c2 cells

    Institute of Scientific and Technical Information of China (English)

    Soundharrajan Ilavenil; Da Hye Kim; Young-Il Jeong; Mariadhas Valan Arasu; Mayakrishnan Vijayakumar; Ponnuraj Nagendra Prabhu; Srisesharam Srigopalram; Ki Choon Choi

    2015-01-01

    Objective: To elucidate the key parameters associated with hydrogen peroxide induced oxidative stress and investigates the mechanism of trigonelline (TG) for reducing the H2O2 induced toxicity in H9c2 cells. Methods: Cytotoxicity and antioxidant activity of TG was assessed by EZ-CYTOX kit. RNA extraction and cDNA synthesized according to the kit manufacture protocol. Apoptosis was measured by the Flowcytometry, general PCR and qPCR. Results: It was found that the TG significantly rescued the morphology of the H9c2 cells. Treatment of cells with TG attenuated H2O2 induced cell deaths and improved the antioxidant activity. In addition, TG regulated the apoptotic gene caspase-3, caspase-9 and anti-apoptotic gene Bcl-2, Bcl-XL during H2O2 induced oxidative stress in H9c2 cells. These results were comparable with quercetin treatment. For evident, flow cytometer results also confirmed the TG significantly reduced the H2O2 induced necrosis and apoptosis in H9c2 cells. However, further increment of TG concentration against H2O2 could induce the necrosis and apoptosis along with H2O2. Conclusions: It is suggested that less than 125 μM of TG could protect the cells from H2O2 induced cell damage by down regulating the caspases and up regulating the Bcl-2 and Bcl-XL expression. Therefore, we suggest the trigonelline could be useful for treatment of oxidative stress mediated cardiovascular diseases in future.

  3. The toxin and antidote puzzle: new ways to control insect pest populations through manipulating inheritance.

    Science.gov (United States)

    Marshall, John M

    2011-01-01

    Insects carry out essential ecological functions, such as pollination, but also cause extensive damage to agricultural crops, and transmit human diseases such as malaria and dengue fever. Advances in insect transgenesis are making it increasingly feasible to engineer genes conferring desirable phenotypes, and gene drive systems are required to spread these genes into wild populations. Medea provides one solution, being able to spread into a population from very low initial frequencies through the action of a maternally-expressed toxin linked to a zygotically-expressed antidote. Several other toxin-antidote combinations are imaginable that distort the offspring ratio in favor of a desired transgene, or drive the population towards an all-male crash. We explore two such systems--Semele, which is capable of spreading a desired transgene into an isolated population in a confined manner; and Merea, which is capable of inducing a local population crash when located on the Z chromosome of a Lepidopteron pest. PMID:21876382

  4. Tunable C2N Membrane for High Efficient Water Desalination

    Science.gov (United States)

    Yang, Yanmei; Li, Weifeng; Zhou, Hongcai; Zhang, Xiaoming; Zhao, Mingwen

    2016-07-01

    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.

  5. 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

  6. New boundary conditions for the c=-2 ghost system

    International Nuclear Information System (INIS)

    We investigate a novel boundary condition for the bc system with central charge c=-2. Its boundary state is constructed and tested in detail. It appears to give rise to the first example of a local logarithmic boundary sector within a bulk theory whose Virasoro zero modes are diagonalizable. (orig.)

  7. Why is the Bond Multiplicity in C2 so Elusive?

    Czech Academy of Sciences Publication Activity Database

    Cooper, D.L.; Penotti, F.E.; Ponec, Robert

    2015-01-01

    Roč. 1053, SI (2015), s. 189-194. ISSN 2210-271X Institutional support: RVO:67985858 Keywords : bond multiplicity in C2 * spin correlation matrices * full GVB and spin-coupled Subject RIV: CC - Organic Chemistry Impact factor: 1.545, year: 2014

  8. Palladium-catalysed direct C-2 methylation of indoles.

    Science.gov (United States)

    Tu, Daoquan; Cheng, Xiuzhi; Gao, Yadong; Yang, Panpan; Ding, Yousong; Jiang, Chao

    2016-08-21

    A direct C-2 methylation reaction of indoles bearing a readily removable N-2-pyrimidyl moiety as a site-specific directing group has been developed with a palladium catalyst. This reaction relied on the use of KF to promote efficient methylation. A moderate to good yield was achieved in a range of indole substrates. PMID:27424955

  9. THE NUCLEOTIDE RECEPTORS ON MOUSE C2C12 MYOTUBES

    NARCIS (Netherlands)

    HENNING, RH; NELEMANS, A; VANDENAKKER, J; DENHERTOG, A

    1992-01-01

    1 The response of C2C12 mouse myotubes to stimulation with adenosine triphosphate (ATP) and other nucleotides was studied by measuring changes in membrane potential. 2 A transient hyperpolarization followed by a slowly declining depolarization of the cells was observed in the presence of ATP (10-mu-

  10. New boundary conditions for the c=-2 ghost system

    Energy Technology Data Exchange (ETDEWEB)

    Creutzig, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Quella, T. [Amsterdam Univ. (Netherlands). KdV Inst. for Mathematics; Schomerus, V. [Center for Mathematical Physics, Hamburg (Germany)]|[King' s College London (United Kingdom). Dept. of Mathematics

    2006-12-15

    We investigate a novel boundary condition for the bc system with central charge c=-2. Its boundary state is constructed and tested in detail. It appears to give rise to the first example of a local logarithmic boundary sector within a bulk theory whose Virasoro zero modes are diagonalizable. (orig.)

  11. Simulace přenosu DVB-C2

    OpenAIRE

    Chovaneček, Libor

    2011-01-01

    Tématem této diplomové práce je simulace přenosu DVB-C2. V první části se práce zaměřuje především na teorii, kde popisuje rozdíly mezi digitálním a analogovým televizním vysíláním. Jsou zde popsány principy fungování systémů DVB-C a DVB-C2 se zaměřením na kanálové kódování a modulaci. Druhá část práce popisuje program pro přenos dat v systému DVB-C2, který byl vytvořen v programovacím prostředí MATLAB. V závěrečné části práce jsou uvedeny výsledky simulací přenosu systému DVB-C2 a jejich por...

  12. Thermochemical study of the molecule BaC2

    International Nuclear Information System (INIS)

    The enthalpy of the reaction Ba(g)+2C(graph.) = BaC2(g) has been determined by Knudsen effusion mass spectrometry over a barium alloy with noble metals contained in a graphite cell. The value ΔH/sup circle-open/0 = 252.5 +- 11.5kJ mol-1 has been obtained from second- and third-law evaluations of the equilibrium vapor in the temperature range 1778--2286 K. This reaction enthalpy has been combined with ancillary literature data to derive the following thermodynamic properties in kJ mol-1 of gaseous BaC2: the atomization energy, Δ/sub at/H/sup circle-open/0 , 1180.9 +- 12.2; the standard heat of formation, Δ/sub f/H/sup circle-open/298 , 437.1 +- 14.2; the enthalpy of sublimation of BaC2(s), Δ/sub sub/H/sup circle-open/298 , 511.2 +- 17.1; and the bond dissociation energy, D/sup circle-open/0 (Ba--C2), 581.7 +- 14.8. The results are discussed with regard to their possible significance in reactor technology

  13. Prevalence of shiga toxins (stx1,stx2),eaeA andhly genes ofEscherichia coli O157:H7 strains among children with acute gastroenteritis in southern of Iran

    Institute of Scientific and Technical Information of China (English)

    Mohammad Kargar; Maryam Homayoon

    2015-01-01

    Objective:To survey the prevalence severe diarrhea arising from these bacteria in children under5 years old inMarvdasht.Methods:In this study faecal sample from615 children aged <5 years old who were hospitalized for gastroenteritis inFars hospitals inIran were collected and then enriched inEscherichia coli(E. coli) broth and modified tryptone soy broth with novobiocin media.Fermentation of sorbitol, lactose and β-glucoronidase activity of isolated strains was examined byCT-SMAC,VRBA and chromogenic media respectively.Then isolation ofE. coli O157:H7 have been confirmed with the use of specific antisera and with multiplexPCR method presence of virulence genes including: stx1,stx2,eaeA,hly has been analyzed.Results:E. coli O157:H7 was detected in7(1.14%) stool specimens.A significant difference was seen between detection rate of isolated bacteria from age groups18-23 months and other age groups(P=0.004). Out of considered virulence genes, only1 of the isolated strains(0.16%) the stx1 andeaeA genes were seen and also all isolated bacteria had resistance to penicillin, ampicillin and erythromycin antibiotics.Conclusions:We found that children <2 years of age were at highest risk of infection withE. coliO157:H7.Regarding severity ofE. coliO157:H7 pathogenesis, low infectious dose and lack of routine assay for detection of these bacteria in clinical laboratory, further and completed studies on diagnosis and genotyping of thisE. coliO157:H7 strain has been recommended.

  14. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis

    Science.gov (United States)

    Seike, Soshi; Miyamoto, Kazuaki; Kobayashi, Keiko; Takehara, Masaya; Nagahama, Masahiro

    2016-01-01

    Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2). All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis. PMID:26807591

  15. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis.

    Directory of Open Access Journals (Sweden)

    Soshi Seike

    Full Text Available Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2. All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis.

  16. Toxin from skin of frogs of the genus Atelopus: differentiation from Dendrobatid toxins.

    Science.gov (United States)

    Fuhrman, F A; Fuhrman, G J; Mosher, H S

    1969-09-26

    A potent, dialyzable toxin (atelopidtoxin) occurs in the skin of frogs of the genus Atelopus. A concentrate of atelopidtoxin from Atelopus zeteki has an LD(50) in mice of 16 micrograms per kilogram. It differs from batrachotoxin, tetrodotoxin, and saxitoxin, the only known nonprotein substances of greater toxicity, as well as from all toxins previously isolated from amphibia. PMID:5807965

  17. Myostatin stimulates, not inihibits, C2C12 myoblast proliferation.

    Science.gov (United States)

    Rodgers, Buel D; Wiedeback, Benjamin D; Hoversten, Knut E; Jackson, Melissa F; Walker, Ryan G; Thompson, Thomas B

    2014-03-01

    The immortal C2C12 cell line originates from dystrophic mouse thigh muscle and has been used to study the endocrine control of muscle cell growth, development, and function, including those actions regulated by myostatin. Previous studies suggest that high concentrations of recombinant myostatin generated in bacteria inhibit C2C12 proliferation and differentiation. Recombinant myostatin generated in eukaryotic systems similarly inhibits the proliferation of primary myosatellite cells, but consequently initiates, rather than inhibits, their differentiation and is bioactive at far lower concentrations. Our studies indicate that 2 different sources of recombinant myostatin made in eukaryotes stimulate, not inhibit, C2C12 proliferation. This effect occurred at different cell densities and serum concentrations and in the presence of IGF-I, a potent myoblast mitogen. This stimulatory effect was comparable to that obtained with TGFβ1, a related factor that also inhibits primary myosatellite cell proliferation. Attenuating the myostatin/activin (ie, Acvr2b) and TGFβ1 receptor signaling pathways with the Alk4/5 and Alk5 inhibitors, SB431542 and SB505142, respectively, similarly attenuated proliferation induced by serum, myostatin or TGFβ1 and in a dose-dependent manner. In serum-free medium, both myostatin and TGFβ1 stimulated Smad2 phosphorylation, but not that of Smad3, and a Smad3 inhibitor (SIS3) only inhibited proliferation in cells cultured in high serum. Thus, myostatin and TGFβ1 stimulate C2C12 proliferation primarily via Smad2. These results together question the physiological relevance of the C2C12 model and previous studies using recombinant myostatin generated in bacteria. They also support the alternative use of primary myosatellite cells and recombinant myostatin generated in eukaryotes. PMID:24424069

  18. Single amino acid insertions in extracellular loop 2 of Bombyx mori ABCC2 disrupt its receptor function for Bacillus thuringiensis Cry1Ab and Cry1Ac but not Cry1Aa toxins.

    Science.gov (United States)

    Tanaka, Shiho; Miyamoto, Kazuhisa; Noda, Hiroaki; Endo, Haruka; Kikuta, Shingo; Sato, Ryoichi

    2016-04-01

    In a previous report, seven Cry1Ab-resistant strains were identified in the silkworm, Bombyx mori; these strains were shown to have a tyrosine insertion at position 234 in extracellular loop 2 of the ABC transporter C2 (BmABCC2). This insertion was confirmed to destroy the receptor function of BmABCC2 and confer the strains resistance against Cry1Ab and Cry1Ac. However, these strains were susceptible to Cry1Aa. In this report, we examined the mechanisms of the loss of receptor function of the transporter by expressing mutations in Sf9 cells. After replacement of one or two of the five amino acid residues in loop 2 of the susceptible BmABCC2 gene [BmABCC2_S] with alanine, cells still showed susceptibility, retaining the receptor function. Five mutants with single amino acid insertions at position 234 in BmABCC2 were also generated, resulting in loop 2 having six amino acids, which corresponds to replacing the tyrosine insertion in the resistant BmABCC2 gene [BmABCC2_R(+(234)Y)] with another amino acid. All five mutants exhibited loss of function against Cry1Ab and Cry1Ac. These results suggest that the amino acid sequence in loop 2 is less important than the loop size (five vs. six amino acids) or loop structure for Cry1Ab and Cry1Ac activity. Several domain-swapped mutant toxins were then generated among Cry1Aa, Cry1Ab, and Cry1Ac, which are composed of three domains. Swapped mutants containing domain II of Cry1Ab or Cry1Ac did not kill Sf9 cells expressing BmABCC2_R(+(234)Y), suggesting that domain II of the Cry toxin is related to the interaction with the receptor function of BmABCC2. This also suggests that different reactions against Bt-toxins in some B. mori strains, that is, Cry1Ab resistance or Cry1Aa susceptibility, are attributable to structural differences in domain II of Cry1A toxins. PMID:26928903

  19. Phylogenetic diversity and similarity of active sites of Shiga toxin (stx) in Shiga toxin-producing Escherichia coli (STEC) isolates from humans and animals.

    Science.gov (United States)

    Asakura, H; Makino, S; Kobori, H; Watarai, M; Shirahata, T; Ikeda, T; Takeshi, K

    2001-08-01

    Nucleotide sequences of Shiga toxin (Stx) genes in STEC from various origins were determined and characterized by phylogenetic analysis based on Shiga toxin (Stx) with those deposited in GenBank. The phylogenetic trees placed Stx1 and Stx2 into two and five groups respectively, and indicated that Stx1 in sheep-origin STEC were placed into a different group from those in other STEC, and that Stx2 of deer-origin STEC also belonged to the unique group and appeared to be distantly related to human-origin STEC. On the other hand, Stx of STEC isolated from cattle, seagulls and flies were closely related to those of human-origin STEC. Such a diversity of Stx suggested that STEC might be widely disseminated in many animal species, and be dependent on their host species or their habitat. In addition, the active sites in both toxins were compared; the active sites in both subunits of Stx in all the animal-origin STEC were identical to those in human-origin STEC, suggesting that all the toxin of STEC from animals might be also cytotoxic, and therefore, such animal-origin STEC might have potential pathogenicity for humans. PMID:11561972

  20. Phylogenetic diversity and similarity of active sites of Shiga toxin (stx) in Shiga toxin-producing Escherichia coli (STEC) isolates from humans and animals.

    Science.gov (United States)

    Asakura, H.; Makino, S.; Kobori, H.; Watarai, M.; Shirahata, T.; Ikeda, T.; Takeshi, K.

    2001-01-01

    Nucleotide sequences of Shiga toxin (Stx) genes in STEC from various origins were determined and characterized by phylogenetic analysis based on Shiga toxin (Stx) with those deposited in GenBank. The phylogenetic trees placed Stx1 and Stx2 into two and five groups respectively, and indicated that Stx1 in sheep-origin STEC were placed into a different group from those in other STEC, and that Stx2 of deer-origin STEC also belonged to the unique group and appeared to be distantly related to human-origin STEC. On the other hand, Stx of STEC isolated from cattle, seagulls and flies were closely related to those of human-origin STEC. Such a diversity of Stx suggested that STEC might be widely disseminated in many animal species, and be dependent on their host species or their habitat. In addition, the active sites in both toxins were compared; the active sites in both subunits of Stx in all the animal-origin STEC were identical to those in human-origin STEC, suggesting that all the toxin of STEC from animals might be also cytotoxic, and therefore, such animal-origin STEC might have potential pathogenicity for humans. PMID:11561972

  1. Resistance of Trichoplusia ni to Bacillus thuringiensis toxin Cry1Ac is independent of alteration of the cadherin-like receptor for Cry toxins.

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    Full Text Available Alteration of binding sites for Bacillus thuringiensis (Bt toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase N (APN1 gene by a trans-regulatory mechanism and the resistance gene has been mapped to the locus of an ABC transporter (ABCC2 gene. However, whether cadherin is also involved with Cry1Ac-resistance in T. ni requires to be understood. Here we report that the Cry1Ac-resistance in T. ni is independent of alteration of the cadherin. The T. ni cadherin cDNA was cloned and the cadherin sequence showed characteristic features known to cadherins from Lepidoptera. Various T. ni cadherin gene alleles were identified and genetic linkage analysis of the cadherin alleles with Cry1Ac-resistance showed no association of the cadherin gene with the Cry1Ac-resistance in T. ni. Analysis of cadherin transcripts showed no quantitative difference between the susceptible and Cry1Ac-resistant T. ni larvae. Quantitative proteomic analysis of midgut BBMV proteins by iTRAQ-2D-LC-MS/MS determined that there was no quantitative difference in cadherin content between the susceptible and the resistant larvae and the cadherin only accounted for 0.0014% (mol% of the midgut BBMV proteins, which is 1/300 of APN1 in molar ratio. The cadherin from both the susceptible and resistant larvae showed as a 200-kDa Cry1Ac-binding protein by toxin overlay binding analysis, and nano-LC-MS/MS analysis of the 200-kDa cadherin determined that there is no quantitative difference between the susceptible and resistant larvae. Results from this study indicate that the Cry1Ac-resistance in T. ni is

  2. Resistance of Trichoplusia ni to Bacillus thuringiensis toxin Cry1Ac is independent of alteration of the cadherin-like receptor for Cry toxins.

    Science.gov (United States)

    Zhang, Xin; Tiewsiri, Kasorn; Kain, Wendy; Huang, Lihua; Wang, Ping

    2012-01-01

    Alteration of binding sites for Bacillus thuringiensis (Bt) toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase N (APN1) gene by a trans-regulatory mechanism and the resistance gene has been mapped to the locus of an ABC transporter (ABCC2) gene. However, whether cadherin is also involved with Cry1Ac-resistance in T. ni requires to be understood. Here we report that the Cry1Ac-resistance in T. ni is independent of alteration of the cadherin. The T. ni cadherin cDNA was cloned and the cadherin sequence showed characteristic features known to cadherins from Lepidoptera. Various T. ni cadherin gene alleles were identified and genetic linkage analysis of the cadherin alleles with Cry1Ac-resistance showed no association of the cadherin gene with the Cry1Ac-resistance in T. ni. Analysis of cadherin transcripts showed no quantitative difference between the susceptible and Cry1Ac-resistant T. ni larvae. Quantitative proteomic analysis of midgut BBMV proteins by iTRAQ-2D-LC-MS/MS determined that there was no quantitative difference in cadherin content between the susceptible and the resistant larvae and the cadherin only accounted for 0.0014% (mol%) of the midgut BBMV proteins, which is 1/300 of APN1 in molar ratio. The cadherin from both the susceptible and resistant larvae showed as a 200-kDa Cry1Ac-binding protein by toxin overlay binding analysis, and nano-LC-MS/MS analysis of the 200-kDa cadherin determined that there is no quantitative difference between the susceptible and resistant larvae. Results from this study indicate that the Cry1Ac-resistance in T. ni is independent of cadherin

  3. Expression of recombinant Clostridium difficile toxin A and B in Bacillus megaterium

    Directory of Open Access Journals (Sweden)

    Nie Weijia

    2008-11-01

    Full Text Available Abstract Background Major Clostridium difficile virulence factors are the exotoxins TcdA and TcdB. Due to the large size and poor stability of the proteins, the active recombinant TcdA and TcdB have been difficult to produce. Results The toxin genes tcdA and tcdB were amplified by PCR using chromosomal DNA from a toxigenic strain as a template, and cloned into a shuttle vector pHis1522. The sequences of both tcdA and tcdB genes in the vector have been verified by DNA sequencing. The constructs were transformed into B. megaterium protoplasts and the protein expression was controlled under a xylose promoter. The recombinant toxins (rTcdA and rTcdB were purified from bacterial crude extracts. Approximately 5 – 10 mg of highly purified recombinant toxins were obtained from one liter of bacterial culture. The resulting rTcdA and rTcdB had similar molecular masses to the native toxins, and their biological activities were found to be similar to their native counterparts after an extensive examination. Conclusion We have generated the full length and active recombinant TcdA and TcdB in Bacillus megaterium.

  4. Animal Toxins: How is Complexity Represented in Databases?

    Science.gov (United States)

    Jungo, Florence; Estreicher, Anne; Bairoch, Amos; Bougueleret, Lydie; Xenarios, Ioannis

    2010-02-01

    Peptide toxins synthesized by venomous animals have been extensively studied in the last decades. To be useful to the scientific community, this knowledge has been stored, annotated and made easy to retrieve by several databases. The aim of this article is to present what type of information users can access from each database. ArachnoServer and ConoServer focus on spider toxins and cone snail toxins, respectively. UniProtKB, a generalist protein knowledgebase, has an animal toxin-dedicated annotation program that includes toxins from all venomous animals. Finally, the ATDB metadatabase compiles data and annotations from other databases and provides toxin ontology. PMID:22069583

  5. Regulation of toxin synthesis in Clostridium botulinum and Clostridium tetani.

    Science.gov (United States)

    Connan, Chloé; Denève, Cécile; Mazuet, Christelle; Popoff, Michel R

    2013-12-01

    Botulinum and tetanus neurotoxins are structurally and functionally related proteins that are potent inhibitors of neuroexocytosis. Botulinum neurotoxin (BoNT) associates with non-toxic proteins (ANTPs) to form complexes of various sizes, whereas tetanus toxin (TeNT) does not form any complex. The BoNT and ANTP genes are clustered in a DNA segment called the botulinum locus, which has different genomic localization (chromosome, plasmid, phage) in the various Clostridium botulinum types and subtypes. The botulinum locus genes are organized in two polycistronic operons (ntnh-bont and ha/orfX operons) transcribed in opposite orientations. A gene called botR lying between the two operons in C. botulinum type A encodes an alternative sigma factor which regulates positively the synthesis of BoNT and ANTPs at the late exponential growth phase and beginning of the stationary phase. In Clostridium tetani, the gene located immediately upstream of tent encodes a positive regulatory protein, TetR, which is related to BotR. C. botulinum and C. tetani genomes contain several two-component systems and predicted regulatory orphan genes. In C. botulinum type A, four two-component systems have been found that positively or negatively regulate the synthesis of BoNT and ANTPs independently of BotR/A. The synthesis of neurotoxin in Clostridia seems to be under the control of complex network of regulation. PMID:23769754

  6. Search for the isomers of C2H3NO and C2H3NS in the Interstellar Medium

    Science.gov (United States)

    Etim, Emmanuel; Chakrabarti, Sandip Kumar; Das, Ankan; Gorai, Prasanta; Arunan, Elangannan

    2016-07-01

    With about 40% of all the known interstellar and circumstellar molecules having their isomeric analogues as known astromolecules, isomerism remains one of the leading themes in interstellar chemistry. In this regard, the recent detection of methyl isocyanate (with a number of isomeric analogues) in the Sgr B2(N) giant molecular cloud opens a new window for the possible astronomical detection of other C_2H_3NO isomers. The present work looks at the possibility of detecting other isomers of methyl isocyanate by considering different factors such as thermodynamic stability of the different isomers with respect to the Energy, Stability and Abundance (ESA) relationship, effect of interstellar hydrogen bonding with respect to the formation these isomers on the surface of the interstellar dust grains, possible formation routes for these isomers, spectroscopic parameters for potential astromolecules among these isomers, chemical modeling among other studies. The same studies are repeated for the C_2H_3NS isomers which are the isoelectroninc analogues of the C_2H_3NO isomers taking into account the unique chemistry of S and O-containing interstellar molecular species. Among the C_2H_3NS isomers, methyl isothiocyanate remains the most potential candidate for astronomical observation.

  7. Synthesis of triple (13C2, 15N), single (14C), and double (14C2) labeled trimetrexate

    International Nuclear Information System (INIS)

    A method was developed for the synthesis of triple (13C2, 14N) labeled trimetrexate. A method for single carbon-14 labeled synthesis is also described. Modifications of the triple labeled synthesis with carbon-14 produced a doubled carbon-14 labeled trimetrexate. (author)

  8. Accumulation and depuration profiles of PSP toxins in the short-necked clam Tapes japonica fed with the toxic dinoflagellate Alexandrium catenella.

    Science.gov (United States)

    Samsur, Mohamad; Yamaguchi, Yasunaga; Sagara, Takefumi; Takatani, Tomohiro; Arakawa, Osamu; Noguchi, Tamao

    2006-09-01

    A toxic dinoflagellate responsible for paralytic shellfish poisoning (PSP), Alexandrium catenella (Ac) was fed to the short-necked clam Tapes japonica, and the accumulation and depuration profiles of PSP toxins were investigated by means of high-performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD). The short-necked clams ingested more than 99% of the Ac cells (4 x 10(7)cells) supplied once at the beginning of experiment, and accumulated a maximal amount of toxin (185 nmol/10 clams) after 12h. The rate of toxin accumulation at that time was 23%, which rapidly decreased thereafter. Composition of the PSP toxin accumulated in the clams obviously different from that of Ac even 0.5h after the cell supply, the proportion of C1+2 being much higher than in Ac, although the reason remains to be elucidated. In contrast, a higher ratio of gonyautoxin (GTX)1+4 than in Ac was detected in the toxin profiles of clam excrements. The variation in toxin composition derived presumably from the transformation of toxin analogues in clams was observed from 0.5h, such as reversal of the ratio of C1 to C2, and appearance of carbamate (saxitoxin (STX), neoSTX and GTX2, 3) and decarbamoyl (dc) derivatives (dcSTX and dcGTX2, 3), which were undetectable in Ac cells. The total amount of toxin distributed over Ac cells, clams and their excrements gradually declined, and only 1% of supplied toxin was detected at the end of experiment. PMID:16887162

  9. A truncated diphtheria toxin based recombinant porcine CTLA-4 fusion toxin.

    Science.gov (United States)

    Peraino, Jaclyn Stromp; Schenk, Marian; Zhang, Huiping; Li, Guoying; Hermanrud, Christina E; Neville, David M; Sachs, David H; Huang, Christene A; Duran-Struuck, Raimon; Wang, Zhirui

    2013-05-31

    Targeted cell therapies are possible through the generation of recombinant fusion proteins that combine a toxin, such as diphtheria toxin (DT), with an antibody or other molecule that confers specificity. Upon binding of the fusion protein to the cell of interest, the diphtheria toxin is internalized which results in protein synthesis inhibition and subsequent cell death. We have recently expressed and purified the recombinant soluble porcine CTLA-4 both with and without N-glycosylation in yeast Pichia pastoris for in vivo use in our preclinical swine model. The glycosylated and non-N-glycosylated versions of this recombinant protein each bind to a porcine CD80 expressing B-cell lymphoma line (LCL13271) with equal affinity (K(D)=13 nM). In this study we have linked each of the glycosylated and non-N-glycosylated soluble porcine CTLA-4 proteins to the truncated diphtheria toxin DT390 through genetic engineering yielding three versions of the porcine CTLA-4 fusion toxins: 1) monovalent glycosylated soluble porcine CTLA-4 fusion toxin; 2) monovalent non-N-glycosylated soluble porcine CTLA-4 fusion toxin and 3) bivalent non-N-glycosylated soluble porcine CTLA-4 fusion toxin. Protein synthesis inhibition analysis demonstrated that while all three fusion toxins are capable of inhibiting protein synthesis in vitro, the non-N-glycosylated porcine CTLA-4 isoforms function most efficiently. Binding analysis using flow cytometry of the porcine CTLA-4 fusion toxins to LCL13271 cells also demonstrated that the non-N-glycosylated porcine CTLA-4 isoforms bind to these cells with higher affinity compared to the glycosylated fusion toxin. The monovalent non-N-glycosylated porcine CTLA-4 fusion toxin was tested in vivo. NSG (NOD/SCID IL-2 receptor γ(-)/(-)) mice were injected with porcine CD80(+) LCL13271 tumor cells. All animals succumbed to tumors and those treated with the monovalent non-N-glycosylated porcine CTLA-4 fusion toxin survived longer based on a symptomatic scoring

  10. A Novel MIF Signaling Pathway Drives the Malignant Character of Pancreatic Cancer by Targeting NR3C2.

    Science.gov (United States)

    Yang, Shouhui; He, Peijun; Wang, Jian; Schetter, Aaron; Tang, Wei; Funamizu, Naotake; Yanaga, Katsuhiko; Uwagawa, Tadashi; Satoskar, Abhay R; Gaedcke, Jochen; Bernhardt, Markus; Ghadimi, B Michael; Gaida, Matthias M; Bergmann, Frank; Werner, Jens; Ried, Thomas; Hanna, Nader; Alexander, H Richard; Hussain, S Perwez

    2016-07-01

    Pancreatic cancers with aberrant expression of macrophage migration inhibitory factor (MIF) are particularly aggressive. To identify key signaling pathways that drive disease aggressiveness in tumors with high MIF expression, we analyzed the expression of coding and noncoding genes in high and low MIF-expressing tumors in multiple cohorts of pancreatic ductal adenocarcinoma (PDAC) patients. The key genes and pathways identified were linked to patient survival and were mechanistically, functionally, and clinically characterized using cell lines, a genetically engineered mouse model, and PDAC patient cohorts. Here, we report evidence of a novel MIF-driven signaling pathway that inhibits the orphan nuclear receptor NR3C2, a previously undescribed tumor suppressor that impacts aggressiveness and survival in PDAC. Mechanistically, MIF upregulated miR-301b that targeted NR3C2 and suppressed its expression. PDAC tumors expressing high levels of MIF displayed elevated levels of miR-301b and reduced levels of NR3C2. In addition, reduced levels of NR3C2 expression correlated with poorer survival in multiple independent cohorts of PDAC patients. Functional analysis showed that NR3C2 inhibited epithelial-to-mesenchymal transition and enhanced sensitivity to the gemcitabine, a chemotherapeutic drug used in PDAC standard of care. Furthermore, genetic deletion of MIF disrupted a MIF-mir-301b-NR3C2 signaling axis, reducing metastasis and prolonging survival in a genetically engineered mouse model of PDAC. Taken together, our results offer a preclinical proof of principle for candidate therapies to target a newly described MIF-miR-301b-NR3C2 signaling axis for PDAC management. Cancer Res; 76(13); 3838-50. ©2016 AACR. PMID:27197190

  11. C2orf62 and TTC17 are involved in actin organization and ciliogenesis in zebrafish and human.

    Science.gov (United States)

    Bontems, Franck; Fish, Richard J; Borlat, Irene; Lembo, Frédérique; Chocu, Sophie; Chalmel, Frédéric; Borg, Jean-Paul; Pineau, Charles; Neerman-Arbez, Marguerite; Bairoch, Amos; Lane, Lydie

    2014-01-01

    Vertebrate genomes contain around 20,000 protein-encoding genes, of which a large fraction is still not associated with specific functions. A major task in future genomics will thus be to assign physiological roles to all open reading frames revealed by genome sequencing. Here we show that C2orf62, a highly conserved protein with little homology to characterized proteins, is strongly expressed in testis in zebrafish and mammals, and in various types of ciliated cells during zebrafish development. By yeast two hybrid and GST pull-down, C2orf62 was shown to interact with TTC17, another uncharacterized protein. Depletion of either C2orf62 or TTC17 in human ciliated cells interferes with actin polymerization and reduces the number of primary cilia without changing their length. Zebrafish embryos injected with morpholinos against C2orf62 or TTC17, or with mRNA coding for the C2orf62 C-terminal part containing a RII dimerization/docking (R2D2) - like domain show morphological defects consistent with imperfect ciliogenesis. We provide here the first evidence for a C2orf62-TTC17 axis that would regulate actin polymerization and ciliogenesis. PMID:24475127

  12. Online Trading C2C Operators Fight for Number One

    Institute of Scientific and Technical Information of China (English)

    DAVID HENDRICKSON

    2006-01-01

    @@ Whether shopping casually or searching for some obscure, hard to find item, more and more Chinese are logging online and turning to customer-to-customer (C2C) network operators for their trading needs rather than bother with the hassles of conventional buying and selling. Proof is in the numbers. A leading technology, new media, and telecom watchdog, Analysys International reports that China's C2C market users more than doubled in 2005 to 37.87 million, while the sector's total transaction value increased from 4.16 billion yuan in 2004, to 13.9billion yuan (US$1.74 billion). Supplanted by a web surfing pool of 100 million and counting, they are trends that Analysys and other industry groups expect will continue in China for some time, fundamentally transforming how the country's independent traders do business.

  13. A rare Cervical Nerve Root, C2-C3 Schwannoma

    Directory of Open Access Journals (Sweden)

    Nilesh Chordia

    2014-04-01

    Full Text Available Schwannomas, neurilemmomas or neurinomas are benign nerve sheath tumors deriving from Schwann cells that occur in the head and neck region in 25-45% of cases 1 .About 10% of schwannoma that occur in the head and neck region generally originate from the vagus or sympathetic nervous system, those arising from C2 nerve root are extremely rare. 2 Preoperative imaging studies such as magnetic resonance imaging (MRI and computed tomography (CT are used to distinguish its location and origin. The treatment of schwannoma is surgical resection, with several surgical modalities have been introduced to preserve the neurological function. We present a rare case of Cervical nerve (C2-C3 root schwannoma of 70 years old male who presented with lateral neck swelling with no neurological deficit ,swelling which also had intervertebral part was removed successfully through neck incision with no post-operative neurological symptoms

  14. Isotope analysis of carbon by C2 molecule spectrum

    International Nuclear Information System (INIS)

    A study was made on inert gas mixture (He, Ne, Ar) with carbon-containing components (CO, CO2, CH4) under conditions of variation of mixture pressure in discharge tube, of carbon-containing components contents and the rate of gas flow through the discharge tube. The use of C2 molecule spectrum enabled to develope the spectroscopic techniques for determination of carbon isotope ratio. The method is universal with respect to molecular form of carbon-containing substance

  15. Fluorescent vibration-rotation excitation of cometary C2

    OpenAIRE

    Gredel, R.; Dishoeck, van, E.F.; Black, J. H.

    1989-01-01

    The statistical equilibrium equations that determine the population densities of the energy levels in cometary C2 molecules due to fluorescent excitation are examined in detail. The adopted model and molecular parameters are discussed, and a theoretical estimate is made of the two intercombination transition moments. From the theoretical population densities in the various rotational levels, flux ratios and synthetic emission profiles are calculated as functions of the a 3Pi(u) - X 1Sigma(g)+...

  16. Heat-shock-induced refolding entails rapid degradation of bsrG toxin mRNA by RNases Y and J1.

    Science.gov (United States)

    Jahn, Natalie; Brantl, Sabine

    2016-02-01

    Gene regulation accomplished by alternative folding of an mRNA is a widely used mechanism. Classical examples are the various transcriptional attenuation mechanisms that employ, for example, leader peptide translation, or binding of a modified protein, an uncharged tRNA or an antisense RNA to the 5' untranslated region of an mRNA. With the discovery of transcriptional and translational riboswitches, it became clear that small metabolites or even metal ions can also alter RNA secondary structures and, hence, gene expression. In addition, biophysical factors like temperature can affect RNA folding, as exemplified by RNA thermometers. We have investigated in detail the type I toxin-antitoxin system bsrG/SR4 from Bacillus subtilis. The antitoxin SR4 is a cis-encoded regulatory RNA that neutralizes BsrG toxin action. SR4 prevents toxin expression by promoting degradation of the toxin mRNA and inhibiting its translation. In addition, upon temperature shock the amount of toxin mRNA decreases significantly. Here, we demonstrate that heat shock induces a refolding in the central region of the toxin mRNA that makes it more accessible to degradation by RNases Y and J1. Furthermore, we show that BsrG might play a role at the onset of stationary phase, when the antitoxin SR4 can no longer prevent toxin synthesis. PMID:26802042

  17. Is There a Quadruple Bond in C2?

    Science.gov (United States)

    de Sousa, David Wilian Oliveira; Nascimento, Marco Antonio Chaer

    2016-05-10

    The chemical structure of the ground state of C2 has been the subject of intense debate after the suggestion that the molecule could exhibit a "fourth" covalent bond. In this paper, we investigate this problem explicitly avoiding all the points of conflict from the previous papers to show that there is no quadruple bond in C2. The generalized product function energy partitioning (GPF-EP) method has been applied to calculate the interference energy (IE) that accounts for the formation of covalent bonds for each bond of the molecule. The IE analysis shows that for the standard σ and π bonds interference exhibits the expected behavior, while for the "fourth" bond interference is a destabilizing factor. To make sure this could not be attributed to a new kind of bond, we performed an equivalent analysis for the (3)Σ(-) excited state of C3 molecule in which similar "bonding" occurs between the two ending carbon atoms. We also show that the difference in force constants of C2 and acetylene can be rationalized in terms of the amount of charge density in the internuclear region by looking at the changes in the overlaps between orbitals along the bond axis. PMID:27045682

  18. Internal Magnetic Field Measurement on C-2 FRC Plasma

    Science.gov (United States)

    Gota, Hiroshi; Knapp, Kurt; Deng, Bihe; Thompson, Matthew; Tuszewski, Michel; van Drie, Alan

    2010-11-01

    Three-axis internal magnetic probes are being developed to measure simultaneously Bz, Bt and Br of a field-reversed configuration (FRC) plasma from the geometric axis (r=0) to outside of the separatrix in C-2. The probe assembly consists of 30 commercial chip-inductors (10 different radial positions of each field-component with 5 cm apart), OD˜0.25'' stainless-steel tube with 5-mil wall for the vacuum boundary, and interlocking Boron-Nitride jackets as a plasma facing material. In C-2, it is important to understand field-structure of FRC plasma during translation and colliding two-FRCs in the confinement section as well as the equilibrium/quiescent phase. With 6-chord interferometry located in the midplane of C-2, the internal structure of FRC can be compared and discussed by using a rigid-rotor profile model for the field and the density of FRCs. The preliminary result of internal field measurements will be presented at the meeting as well as the detailed probe design.

  19. V18P9C2. A complex phosphide carbide

    International Nuclear Information System (INIS)

    V18P9C2 crystallizes in the orthorhombic space group Pmma with the lattice parameters a = 17.044(3), b = 3.2219(7), and c = 13.030(2) Aa, Z = 2. The crystal structure is composed of 19 symmetry-independent atoms. The crystal structure is considered as a network formed by the transition metal atoms exhibiting cubic, trigonal prismatic, and octahedral voids centered by V, P, and C atoms, respectively. Vice versa, the V and P atoms form a three-dimensional network. The two CV6 octahedra are edge- and corner-connected to chains running parallel to [010]. The five unique P atoms are trigonal prismatically coordinated by V atoms with one to three faces capped again by a V atom. The V atoms have mainly cubic environments formed solely by V or by V and P atoms. V18P9C2 exhibits some structural relations to other compounds of the ternary system V-P-C as well as to other intermetallic phases. Despite the low carbon content, V18P9C2 is considered as a ternary compound rather than an interstitially stabilized (binary) phosphide in view of its special structural features.

  20. Review on Panton Valentine leukocidin toxin carriage among Staphylococcus aureus.

    Science.gov (United States)

    Shrestha, B

    2013-09-01

    Panton Valentine leukocidin is a toxin making pores in the polymorphonuclear cells which is a virulence factor of some strains of Staphylococcus aureus. Initially it was produced by methicillin susceptible Staphylococcus aureus only. Later with the acquisition of mecA gene has lead it to be PVL positive methicillin resistant Staphylococcus aureus. Since MRSA are resistant to many antibiotics and further they produce a toxin the infections by PVL positive MRSA has become a challenge. PVL positive MRSA a virulent strain of drug resistant superbug MRSA that has spread around the world, has claimed many lives in UK, Europe, USA and Australia. Some strains of superbug attack the healthy young people and kill within 24 hrs. PVL positive Staphylococcus aureus has been reported to be associated with skin and soft tissue infections however they also cause invasive infections and necrotizing pneumonia. These microorganisms known to be community associated have spread to hospitals. Hospital acquired infection by such microorganisms lead to an increase in mortality hence should be controlled before they become prevalent in hospitals. PMID:24908537

  1. Over-expression of the transcription factor, ZBP-89, leads to enhancement of the C2C12 myogenic program

    OpenAIRE

    Salmon, Morgan; Owens, Gary K.; Zehner, Zendra E.

    2009-01-01

    Myogenesis involves the complex interplay between the down-regulation of non-muscle genes and the up-regulation of muscle-specific genes. This interplay is controlled by the myogenic regulatory factors Myf5, MRF4, MyoD and myogenin. To trigger the up-regulation of these muscle-specific factors, certain environmental cues, such as the removal of serum, signal C2C12 myoblast cells to withdraw from cell cycle, fuse and activate muscle-specific genes. Here, the level of ZBP-89 (zfp148), a Krüppel...

  2. Further characterization of Mycobacterium ulcerans toxin.

    Science.gov (United States)

    Hockmeyer, W T; Krieg, R E; Reich, M; Johnson, R D

    1978-07-01

    Mycobacterium ulcerans produces an exotoxin in culture which, when inoculated into guinea pig skin, causes inflammation, necrosis, edema, and other histopathological changes resembling those in infections of humans. The toxin was resistant to heat and to alkalies and was moderately acid labile. Toxic activity was destroyed by Pronase, phospholipase, lipase, amylase, and glucosidase but not by trypsin, collagenase, cellulase, lysozyme, hyaluronidase, or neuraminidase. Toxic activity was resistant to treatment with 2-mercaptoethanol, urea, guanidine hydrochloride, p-chloromercuribenzoate, ethylenediaminetetraacetate, and sodium deoxycholate but was destroyed by sodium m-periodate and sodium dodecyl sulfate. The toxin was precipitated by a wide range of ammonium sulfate concentrations. Extraction with chlorofrom-methanol or petroleum ether destroyed its activity. Isopycnic density gradient ultracentrifugation in KBr produced a high-density lipoprotein layer with a 24-fold increase in specific activity. The results indicate that this toxin is a high-molecular-weight phospholipoprotein-polysaccharide complex. PMID:30694

  3. Functional evaluation of human ClC-2 chloride channel mutations associated with idiopathic generalized epilepsies.

    Science.gov (United States)

    Niemeyer, María Isabel; Yusef, Yamil R; Cornejo, Isabel; Flores, Carlos A; Sepúlveda, Francisco V; Cid, L Pablo

    2004-09-16

    The ClC-2 Cl- channel has been postulated to play a role in the inhibitory GABA response in neurons or to participate in astrocyte-dependent extracellular electrolyte homeostasis. Three different mutations in the CLCN2 gene, encoding the voltage-dependent homodimeric ClC-2 channel, have been associated with idiopathic generalized epilepsy (IGE). We study their function in vitro by patch clamp and confocal microscopy in transiently transfected HEK-293 cells. A first mutation predicts a premature stop codon (M200fsX231). An altered splicing, due to an 11-bp deletion in intron 2 (IVS2-14del11), predicts exon 3 skipping (Delta74-117). A third is a missense mutation (G715E). M200fsX231 and Delta74-117 are nonfunctional and do not affect the function of the normal (wild type, WT) channel. Neither M200fsX231 nor Delta74-117 reach the plasma membrane. Concerning the IVS2-14del11 mutation, we find no difference in the proportion of exon-skipped to normally spliced mRNA using a minigene approach and, on this basis, predict no alteration in channel expression in affected individuals. G715E has voltage dependence and intracellular Cl- dependence indistinguishable from WT channels. ClC-2 channels are shown to be sensitive to intracellular replacement of ATP by AMP, which accelerates the opening and closing kinetics. This effect is diminished in the G715E mutant and not significant in WT+G715E coexpression. We do not know whether, in a situation of cellular ATP depletion, this might become pathological in individuals carrying the mutation. We postulate that loss of function mutation M200fsX231 of ClC-2 might contribute to the IGE phenotype through a haploinsufficiency mechanism. PMID:15252188

  4. Atp2c2 Is Transcribed From a Unique Transcriptional Start Site in Mouse Pancreatic Acinar Cells.

    Science.gov (United States)

    Fenech, Melissa A; Sullivan, Caitlin M; Ferreira, Lucimar T; Mehmood, Rashid; MacDonald, William A; Stathopulos, Peter B; Pin, Christopher L

    2016-12-01

    Proper regulation of cytosolic Ca(2+) is critical for pancreatic acinar cell function. Disruptions in normal Ca(2+) concentrations affect numerous cellular functions and are associated with pancreatitis. Membrane pumps and channels regulate cytosolic Ca(2+) homeostasis by promoting rapid Ca(2+) movement. Determining how expression of Ca(2+) modulators is regulated and the cellular alterations that occur upon changes in expression can provide insight into initiating events of pancreatitis. The goal of this study was to delineate the gene structure and regulation of a novel pancreas-specific isoform for Secretory Pathway Ca(2+) ATPase 2 (termed SPCA2C), which is encoded from the Atp2c2 gene. Using Next Generation Sequencing of RNA (RNA-seq), chromatin immunoprecipitation for epigenetic modifications and promoter-reporter assays, a novel transcriptional start site was identified that promotes expression of a transcript containing the last four exons of the Atp2c2 gene (Atp2c2c). This region was enriched for epigenetic marks and pancreatic transcription factors that promote gene activation. Promoter activity for regions upstream of the ATG codon in Atp2c2's 24th exon was observed in vitro but not in in vivo. Translation from this ATG encodes a protein aligned with the carboxy terminal of SPCA2. Functional analysis in HEK 293A cells indicates a unique role for SPCA2C in increasing cytosolic Ca(2+) . RNA analysis indicates that the decreased Atp2c2c expression observed early in experimental pancreatitis reflects a global molecular response of acinar cells to reduce cytosolic Ca(2+) levels. Combined, these results suggest SPCA2C affects Ca(2+) homeostasis in pancreatic acinar cells in a unique fashion relative to other Ca(2+) ATPases. J. Cell. Physiol. 231: 2768-2778, 2016. © 2016 Wiley Periodicals, Inc. PMID:27017909

  5. Recent advances in the medicinal chemistry of polyamine toxins

    DEFF Research Database (Denmark)

    Strømgaard, K; Andersen, K; Krogsgaard-Larsen, P;

    2001-01-01

    This review describes the recent developments in the field of polyamine toxins, with focus on structure activity relationship investigations, including studies of importance of the polyamine moiety for biological activity, photolabeling studies using polyamine toxins as templates, as well as use ...... solid phase methods for the synthesis of polyamine toxins. The review is mainly concerned with effects of polyamine toxins on nicotinic acetylcholine receptors and ionotropic glutamate receptors....

  6. Recent Insights into Clostridium perfringens Beta-Toxin

    OpenAIRE

    Masahiro Nagahama; Sadayuki Ochi; Masataka Oda; Kazuaki Miyamoto; Masaya Takehara; Keiko Kobayashi

    2015-01-01

    Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT) that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. Thes...

  7. Structural interactions of a voltage sensor toxin with lipid membranes

    OpenAIRE

    Mihailescu, Mihaela; Krepkiy, Dmitriy; Milescu, Mirela; Gawrisch, Klaus; Swartz, Kenton J.; White, Stephen

    2014-01-01

    Tarantula venom contains protein toxins that interact with diverse families of ion channels and alter their activity. A number of tarantula toxins are known to interact with membranes and are thought to bind to ion channel proteins within the lipid bilayer. In the present study, we find that tarantula toxins influence the structure and dynamics of the lipid bilayer, and that the toxin orients itself within membranes to facilitate formation of the toxin–channel complexes. Our results have impl...

  8. Natural Toxins for Use in Pest Management

    Directory of Open Access Journals (Sweden)

    Kevin K. Schrader

    2010-07-01

    Full Text Available Natural toxins are a source of new chemical classes of pesticides, as well as environmentally and toxicologically safer molecules than many of the currently used pesticides. Furthermore, they often have molecular target sites that are not exploited by currently marketed pesticides. There are highly successful products based on natural compounds in the major pesticide classes. These include the herbicide glufosinate (synthetic phosphinothricin, the spinosad insecticides, and the strobilurin fungicides. These and other examples of currently marketed natural product-based pesticides, as well as natural toxins that show promise as pesticides from our own research are discussed.

  9. Streptococcal toxins: role in pathogenesis and disease.

    Science.gov (United States)

    Barnett, Timothy C; Cole, Jason N; Rivera-Hernandez, Tania; Henningham, Anna; Paton, James C; Nizet, Victor; Walker, Mark J

    2015-12-01

    Group A Streptococcus (Streptococcus pyogenes), group B Streptococcus (Streptococcus agalactiae) and Streptococcus pneumoniae (pneumococcus) are host-adapted bacterial pathogens among the leading infectious causes of human morbidity and mortality. These microbes and related members of the genus Streptococcus produce an array of toxins that act against human cells or tissues, resulting in impaired immune responses and subversion of host physiological processes to benefit the invading microorganism. This toxin repertoire includes haemolysins, proteases, superantigens and other agents that ultimately enhance colonization and survival within the host and promote dissemination of the pathogen. PMID:26433203

  10. Vapor-hydrate phases equilibrium of (CH4+C2H6)and (CH4+C2H4) systems

    Institute of Scientific and Technical Information of China (English)

    Ma Qinglan; Chen Guangjin; Zhang Lingwei

    2008-01-01

    Separation of the (C1 + C2) hydrocarbon system is of importance in natural gas processing and ethylene production. However it is the bottleneck because of its high refrigeration energy consumption,and needs to be urgently addressed. The technology of separating gas mixtures by forming hydrate could be used to separate (C1 + C2) gas mixtures at around 0 ℃ and has attracted increasing attention worldwide. In this paper, investigation of vapor-hydrate two-phase equilibrium was carried out for (C1+ C2) systems with and without tetrahydrofuran (THF). The compositions of vapor and hydrate phases under phase equilibrium were studied with model algorithm when structure Ⅰ and structure Ⅱ hydrates coexisted for the (methane + ethane) system. The average deviation between the modeled and actual mole fractions of ethane in hydrate and vapor phases was 0.55%, and that of ethylene was 5.7% when THF was not added. The average deviation of the mole fraction of ethane in vapor phase was 11.46% and ethylene was 7.38% when THF was added. The test results showed that the proposed algorithm is practicable.

  11. Characterisation of cholera toxin by liquid chromatography - Electrospray mass spectrometry

    NARCIS (Netherlands)

    Baar, B.L.M. van; Hulst, A.G.; Wils, E.R.J.

    1999-01-01

    Cholera toxin, one of the toxins that may be generated by various strains of the bacterium Vibrio cholerae, can be considered as a substance possibly used in biological warfare. The possibilities of characterising the toxin by liquid chromatography electrospray mass spectrometry (LC-ES-MS) were inve

  12. Effect of treatment with botulinum toxin on spasticity.

    OpenAIRE

    Das, T K; Park, D M

    1989-01-01

    Botulinum toxin, a product of Clostridium botulinum, produces presynaptic neuromuscular block by preventing release of acetylcholine from nerve endings. The toxin was injected directly into the skeletal muscles of six patients with severe spasticity due to stroke-related hemiplegia. It produced both subjective and objective improvement. The toxin injections were well tolerated and no significant side effect was reported.

  13. Identification and molecular characterization of five putative toxins from the venom gland of the snake Philodryas chamissonis (Serpentes: Dipsadidae).

    Science.gov (United States)

    Urra, Félix A; Pulgar, Rodrigo; Gutiérrez, Ricardo; Hodar, Christian; Cambiazo, Verónica; Labra, Antonieta

    2015-12-15

    Philodryas chamissonis is a rear-fanged snake endemic to Chile. Its bite produces mild to moderate symptoms with proteolytic and anti-coagulant effects. Presently, the composition of the venom, as well as, the biochemical and structural characteristics of its toxins, remains unknown. In this study, we cloned and reported the first full-length sequences of five toxin-encoding genes from the venom gland of this species: Type III snake venom metalloprotease (SVMP), snake venom serine protease (SVSP), Cysteine-rich secretory protein (CRISP), α and β subunits of C-type lectin-like protein (CLP) and C-type natriuretic peptide (NP). These genes are highly expressed in the venom gland and their sequences exhibited a putative signal peptide, suggesting that these are components of the venom. These putative toxins had different evolutionary relationships with those reported for some front-fanged snakes, being SVMP, SVSP and CRISP of P. chamissonis closely related to the toxins present in Elapidae species, while NP was more related to those of Viperidae species. In addition, analyses suggest that the α and β subunits of CLP of P. chamissonis might have a α-subunit scaffold in common with Viperidae species, whose highly variable C-terminal region might have allowed the diversification in α and β subunits. Our results provide the first molecular description of the toxins possibly implicated in the envenomation of prey and humans by the bite of P. chamissonis. PMID:26410112

  14. Enterotoxemia associated with beta2 toxin-producing Clostridium perfringens type A in two Asiatic black bears (Selenarctos thibetanus).

    Science.gov (United States)

    Greco, Grazia; Madio, Anna; Martella, Vito; Campolo, Marco; Corrente, Marialaura; Buonavoglia, Domenico; Buonavoglia, Canio

    2005-03-01

    Beta2 (beta2) toxin-producing Clostridium perfringens type A strains were found to be associated with necrotic and hemorrhagic intestinal lesions in 2 Asiatic black bears (Selenarctos thibetanus) that died suddenly. Ten isolates were obtained from the liver, lungs, heart, and small and large intestine of the animals and were examined by multiplex polymerase chain reaction for the genes encoding the 4 lethal toxins (alpha, beta, epsilon, and iota) for classification into toxin types as well as for the genes encoding enterotoxin and the novel beta2-toxin for subclassification. In addition, the cpb2 sequence of the 10 isolates was different from the published sequence of cpb2 of pig type C isolate CWC245, whereas it was highly similar to the cpb2 sequence of the C. perfringens type A strain 13. This finding suggests the existence of 2 cpb2 subtypes. This is the first report of enterotoxemia associated with the presence of C. perfringens producing beta2-toxin in the tissues and intestinal content of Asiatic black bears. PMID:15825503

  15. Identification and characterization of two novel toxins expressed by the lethal honey bee pathogen Paenibacillus larvae, the causative agent of American foulbrood.

    Science.gov (United States)

    Fünfhaus, Anne; Poppinga, Lena; Genersch, Elke

    2013-11-01

    Paenibacillus larvae is a Gram-positive bacterial pathogen causing the epizootic American foulbrood in honey bee larvae. Four so-called enterobacterial repetitive intergenic consensus (ERIC) genotypes of P. larvae exist with P. larvae genotypes ERIC I and ERIC II being responsible for disease outbreaks all over the world. Very few molecular data on the pathogen, on pathogenesis or on virulence factors exist. We now identified two genomic loci in P. larvae ERIC I coding for two binary AB toxins, Plx1 and Plx2. In silico analyses revealed that Plx1 is the third member of an enigmatic family of AB toxins so far only comprising MTX1 of Lysinibacillus sphaericus and pierisin-like toxins expressed by several butterflies. Plx2 is also remarkable because the A-domain is highly similar to C3 exoenzymes, which normally are single domain proteins, while the B-domain is homologous to B-domains of C2-toxins. We constructed P. larvae mutants lacking expression of Plx1, Plx2 or both toxins and demonstrated that these toxins are important virulence factors for P. larvae ERIC I. PMID:23992535

  16. Local symmetries of finite type hypersurfaces in C2

    Institute of Scientific and Technical Information of China (English)

    KOL(AR) Martin

    2006-01-01

    The first part of this paper gives a complete description of local automorphism groups for Levi degenerate hypersurfaces of finite type in C2. It is also proved that, with the exception of hypersurfaces of the form v = |z|k, local automorphisms are always determined by their 1-jets. Using this result, the second part describes special normal forms which by an additional normalization eliminate the nonlinear symmetries of the model and allows to decide effectively about local equivalence of two hypersurfaces given in this normal form.

  17. Polynomials with general C^2-fibers are variables. I

    OpenAIRE

    Kaliman, Shulim

    1999-01-01

    Suppose that X' is a smooth affine algebraic variety of dimension 3 with H_3(X')=0 which is a UFD and whose invertible functions are constants. Suppose that Z is a Zariski open subset of X which has a morphism p : Z -> U into a curve U such that all fibers of p are isomorphic to C^2. We prove that X' is isomorphic to C^3 iff none of irreducible components of X'-Z has non-isolated singularities. Furthermore, if X' is C^3 then p extends to a polynomial on C^3 which is linear in a suitable coord...

  18. Shiga Toxin 1–Producing Shigella sonnei Infections, California, United States, 2014–2015

    OpenAIRE

    Lamba, Katherine; Nelson, Jennifer A.; Kimura, Akiko C.; Poe, Alyssa; Collins, Joan; Kao, Annie S.; Cruz, Laura; Inami, Gregory; Vaishampayan, Julie; Garza, Alvaro; Chaturvedi, Vishnu; Vugia, Duc J.

    2016-01-01

    Shiga toxins (Stx) are primarily associated with Shiga toxin–producing Escherichia coli and Shigella dysenteriae serotype 1. Stx production by other shigellae is uncommon, but in 2014, Stx1-producing S. sonnei infections were detected in California. Surveillance was enhanced to test S. sonnei isolates for the presence and expression of stx genes, perform DNA subtyping, describe clinical and epidemiologic characteristics of case-patients, and investigate for sources of infection. During June 2...

  19. INSECTICIDAL TOXIN FROM BACILLUS THURINGIENSIS IS RELEASED FROM ROOTS OF TRANSGENIC BT CORN IN VITRO AND IN SITU. (R826107)

    Science.gov (United States)

    AbstractThe insecticidal toxin encoded by the cry1Ab gene from Bacillus thuringiensis was released in root exudates from transgenic Bt corn during 40 days of growth in soil amended to 0, 3, 6, 9, or 12% (v/v) with montmorillonite or kaolinite in a...

  20. Staphylococcus hyicus exfoliative toxin: Purification and demonstration of antigenic diversity among toxins from virulent strains

    DEFF Research Database (Denmark)

    Andresen, Lars Ole; Bille-Hansen, Vivi; Wegener, Henrik Caspar

    1997-01-01

    hydrophobic interaction chromatography and successively anion exchange chromatography. The purified toxin was tested in a piglet skin assay. Weak epidermal lesions were macroscopically and microscopically similar to lesions caused by (NH4)(2)SO4-precipitated culture supernatant from the same strain. Addition...... of 0.5 mM CuSO4 to the purified toxin resulted in more intense skin alterations comparable to lesions caused by precipitated culture supernatant diluted 1:10. These results indicated that the activity of the exfoliative toxin was dependent on the presence of Cu2+. Polyclonal and monoclonal antibodies....... hyicus. These results showed antigenic diversity among exfoliative toxins produced by different strains of S. hyicus. (C) 1997 Academic Press Limited....

  1. A Cell-Based Fluorescent Assay to Detect the Activity of Shiga Toxin and Other Toxins That Inhibit Protein Synthesis

    Science.gov (United States)

    Escherichia coli O157:H7, a major cause of food-borne illness, produces Shiga toxins that block protein synthesis by inactivating the ribosome. In this chapter we describe a simple cell-based fluorescent assay to detect Shiga toxins and inhibitors of toxin activity. The assay can also be used to d...

  2. Staphylococcus hyicus exfoliative toxin: Purification and demonstration of antigenic diversity among toxins from virulent strains

    DEFF Research Database (Denmark)

    Andresen, Lars Ole; Bille-Hansen, Vivi; Wegener, Henrik Caspar

    1997-01-01

    The exfoliative toxin produced by Staphylococcus hyicus strain 1289D-88 was purified as a single protein of approximately 30 kDa. Extracellular proteins of S. hyicus grown under small scale fermentation conditions were precipitated with ammonium sulfate. Separation of proteins was performed by....... hyicus. These results showed antigenic diversity among exfoliative toxins produced by different strains of S. hyicus. (C) 1997 Academic Press Limited....

  3. Toxins and antimicrobial peptides: interactions with membranes

    Science.gov (United States)

    Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.

    2009-08-01

    The innate immunity to pathogenic invasion of organisms in the plant and animal kingdoms relies upon cationic antimicrobial peptides (AMPs) as the first line of defense. In addition to these natural peptide antibiotics, similar cationic peptides, such as the bee venom toxin melittin, act as nonspecific toxins. Molecular details of AMP and peptide toxin action are not known, but the universal function of these peptides to disrupt cell membranes of pathogenic bacteria (AMPs) or a diverse set of eukaryotes and prokaryotes (melittin) is widely accepted. Here, we have utilized spectroscopic techniques to elucidate peptide-membrane interactions of alpha-helical human and mouse AMPs of the cathelicidin family as well as the peptide toxin melittin. The activity of these natural peptides and their engineered analogs was studied on eukaryotic and prokaryotic membrane mimics consisting of melittin and human cathelicidin embedded in bilayer vesicles. Collectively, our results provide clues to the functional structures of the engineered and toxic peptides and may impact the design of synthetic antibiotic peptides that can be used against the growing number of antibiotic-resistant pathogens.

  4. Frey syndrome treatment with botulinum toxin.

    Science.gov (United States)

    Dulguerov, P; Quinodoz, D; Cosendai, G; Piletta, P; Lehmann, W

    2000-06-01

    The goal of this work is to present our results of the intradermic infiltration with botulinum toxin in patients with Frey syndrome. Sixteen hemifaces in 15 patients were studied. Gustatory stimulation was evoked by sucking on a slice of lemon while measurements were done on both hemifaces, with the normal side being used as a control. Skin temperature and color (erythema) were measured with a digital surface thermometer and a skin chromameter, respectively. Sweat quantity and surface were measured by using the previously described blotting paper and iodine-sublimated paper histogram methods, respectively. Testing was repeated 2 weeks after skin infiltration with botulinum toxin (dilution of 50 U/mL). The interinjection distances were 1 cm, and 0.1 mL (5 U) was infiltrated at each injection site. Frey syndrome complaints disappeared in all patients. Small residual amounts of sweat were measurable. The difference in sweat quantity before and after botulinum toxin infiltration was significant in every patient (P < 0.001). Skin temperature and color measurement gave inconclusive results. In conclusion, Frey syndrome treatment with botulinum toxin is an efficient and well-tolerated technique. Further work should address the optimal injection parameters. PMID:10828793

  5. Okadaic Acid: More than a Diarrheic Toxin

    Directory of Open Access Journals (Sweden)

    Josefina Méndez

    2013-10-01

    Full Text Available Okadaic acid (OA is one of the most frequent and worldwide distributed marine toxins. It is easily accumulated by shellfish, mainly bivalve mollusks and fish, and, subsequently, can be consumed by humans causing alimentary intoxications. OA is the main representative diarrheic shellfish poisoning (DSP toxin and its ingestion induces gastrointestinal symptoms, although it is not considered lethal. At the molecular level, OA is a specific inhibitor of several types of serine/threonine protein phosphatases and a tumor promoter in animal carcinogenesis experiments. In the last few decades, the potential toxic effects of OA, beyond its role as a DSP toxin, have been investigated in a number of studies. Alterations in DNA and cellular components, as well as effects on immune and nervous system, and even on embryonic development, have been increasingly reported. In this manuscript, results from all these studies are compiled and reviewed to clarify the role of this toxin not only as a DSP inductor but also as cause of alterations at the cellular and molecular levels, and to highlight the relevance of biomonitoring its effects on human health. Despite further investigations are required to elucidate OA mechanisms of action, toxicokinetics, and harmful effects, there are enough evidences illustrating its toxicity, not related to DSP induction, and, consequently, supporting a revision of the current regulation on OA levels in food.

  6. Future Avenues to Decrease Uremic Toxin Concentration.

    Science.gov (United States)

    Vanholder, Raymond C; Eloot, Sunny; Glorieux, Griet L R L

    2016-04-01

    In this article, we review approaches for decreasing uremic solute concentrations in chronic kidney disease and in particular, in end-stage renal disease (ESRD). The rationale to do so is the straightforward relation between concentration and biological (toxic) effect for most toxins. The first section is devoted to extracorporeal strategies (kidney replacement therapy). In the context of high-flux hemodialysis and hemodiafiltration, we discuss increasing dialyzer blood and dialysate flows, frequent and/or extended dialysis, adsorption, bioartificial kidney, and changing physical conditions within the dialyzer (especially for protein-bound toxins). The next section focuses on the intestinal generation of uremic toxins, which in return is stimulated by uremic conditions. Therapeutic options are probiotics, prebiotics, synbiotics, and intestinal sorbents. Current data are conflicting, and these issues need further study before useful therapeutic concepts are developed. The following section is devoted to preservation of (residual) kidney function. Although many therapeutic options may overlap with therapies provided before ESRD, we focus on specific aspects of ESRD treatment, such as the risks of too-strict blood pressure and glycemic regulation and hemodynamic changes during dialysis. Finally, some recommendations are given on how research might be organized with regard to uremic toxins and their effects, removal, and impact on outcomes of uremic patients. PMID:26500179

  7. Treatment of Frontal Hyperhidrosis With Botulinum Toxin

    Directory of Open Access Journals (Sweden)

    Ayşe Esra Koku Aksu

    Full Text Available Focal hyperhidrosis is usually localized to the axillae, palms and soles. Less frequently, hyperhidrosis may be confined to the forehead and may have negative impact on patient’s quality of life. A 34-year-old man presented to our clinic with the complaint of frontal hyperhidrosis. He was treated with botulinum toxin A. Thirty points were marked over the forehead and at each injection point, 0.15 ml (3U botulinum toxin A were injected intracutaneously. Hyperhidrosis was significantly reduced and the effect lasted for 12 months. Skindex-29, a quality-of-life measure for skin disease, was administered to the patient at the beginning and at the end of second week of botulinum toxin A injection. There was a significant improvement on the Skindex-29 scale at the end of the treatment. There was no any side effect detected during and after the treatment. Botulinum toxin A treatment is considered to be effective and safe for frontal hyperhidrosis.

  8. Natural toxins for use in pest management

    Science.gov (United States)

    Natural toxins are a source of new chemical classes of pesticides, as well as environmentally and toxicologically safer molecules than many of the currently used pesticides. Furthermore, they often have molecular target sites that are not exploited by currently marketed pesticides. There are highly ...

  9. Type II Toxin-antitoxin distribution and adaptive aspects on Xanthomonas genomes: focus on Xanthomonas citri

    Directory of Open Access Journals (Sweden)

    Paula Maria Moreira Martins

    2016-05-01

    Full Text Available Prokaryotic toxin-antitoxin (TA systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of ten Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes.

  10. Type II Toxin-Antitoxin Distribution and Adaptive Aspects on Xanthomonas Genomes: Focus on Xanthomonas citri.

    Science.gov (United States)

    Martins, Paula M M; Machado, Marcos A; Silva, Nicholas V; Takita, Marco A; de Souza, Alessandra A

    2016-01-01

    Prokaryotic toxin-antitoxin (TA) systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of 10 Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB, and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB) was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes. PMID:27242687

  11. Evolution of the biochemistry of the photorespiratory C2 cycle.

    Science.gov (United States)

    Hagemann, M; Fernie, A R; Espie, G S; Kern, R; Eisenhut, M; Reumann, S; Bauwe, H; Weber, A P M

    2013-07-01

    Oxygenic photosynthesis would not be possible without photorespiration in the present day O2 -rich atmosphere. It is now generally accepted that cyanobacteria-like prokaryotes first evolved oxygenic photosynthesis, which was later conveyed via endosymbiosis into a eukaryotic host, which then gave rise to the different groups of algae and streptophytes. For photosynthetic CO2 fixation, all these organisms use RubisCO, which catalyses both the carboxylation and the oxygenation of ribulose 1,5-bisphosphate. One of the reaction products of the oxygenase reaction, 2-phosphoglycolate (2PG), represents the starting point of the photorespiratory C2 cycle, which is considered largely responsible for recapturing organic carbon via conversion to the Calvin-Benson cycle (CBC) intermediate 3-phosphoglycerate, thereby detoxifying critical intermediates. Here we discuss possible scenarios for the evolution of this process toward the well-defined 2PG metabolism in extant plants. While the origin of the C2 cycle core enzymes can be clearly dated back towards the different endosymbiotic events, the evolutionary scenario that allowed the compartmentalised high flux photorespiratory cycle is uncertain, but probably occurred early during the algal radiation. The change in atmospheric CO2 /O2 ratios promoting the acquisition of different modes for inorganic carbon concentration mechanisms, as well as the evolutionary specialisation of peroxisomes, clearly had a dramatic impact on further aspects of land plant photorespiration. PMID:23198988

  12. 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.

  13. Expression of C2A domain of synaptotagmin I fusion protein and its imaging in the ischemia-reperfusion rat model

    International Nuclear Information System (INIS)

    Objective: To evaluate myocardial apoptosis with 99Tcm-C2A-GST myocardial imaging using the recombined C2A domain of Synaptotagmin I by gene engineering. Methods: (1) The C2A gene was inserted into the prokaryotic glutathione S-transferate (GST) fusion protein expression plasmid pGEX-6P-1. The recombinant plasmid was transformed into E. coli BL21. C2A-GST fusion protein was purified after BL21 was induced with isopropyl-β-D-1-thiogalactopyranoside (IPTG). (2) The activity of fusion protein was identified by cell binding test with fluorescein-5-isothiocyanate (FITC)-C2A-GST. (3) The C2A-GST fusion protein was labeled with 99Tcm using 2-iminothiophene hydrocoride method. Radiochemical purity was determined with thin layer chromatography. (4) 99Tcm-C2A-GST (7.4 MBq) was injected to ischemia-reperfusion rat models through tail vein. The image was acquired with SPECT at 1 h after injection, and then hearts were removed, rinsed with saline and dyed with triphenyl tetrazolium coride (TTC). The ischemic myocardium was separated from the viable myocardium and was weighted. Its radioactivity was measured by gamma counting. The difference of uptake of radiotracer between ischemic myocardium and normal myocardium was compared using percentage activity of injected dose per gram of tissue (% ID/g) with standard deviation. SPSS 12.0 and t-test were used for data analysis. Results: (1) C2A-GST fusion protein was successfully expressed and its relative molecular weight was 3.8 x 104. (2) FITC-C2A-GST binding to apoptotic cells could be observed by fluorescent microscopy. (3) The radiochemical purity of 99Tcm-C2A-GST was (98.90 ±0.43)%. (4) The imaging studies showed that there was focal uptake of radioactivity in the ischemic myocardium. In vitro uptake of 99Tcm-C2A-GST was (2.41±0.32) % ID/g by the ischemic myocardium, however 99Tcm-C2A-GST-N-hydroxysuccinimide (C2A-GST-NHS) was (0.82±0.24) % ID/g. There was statistically significant difference between those two groups (t=10

  14. Cloning of α-β fusion gene from Clostridium perfringens and its expression

    Institute of Scientific and Technical Information of China (English)

    Jia-Ning Bai; Yan Zhang; Bao-Hua Zhao

    2006-01-01

    AIM: To study the cloning of α-β fusion gene from Clostridium perfringens and the immunogenicity of α-β fusion expression.METHODS: Cloning was accomplished after PCR amplification from strains NCTC64609 and C58-1 of the protective antigen genes of α-toxin and β-toxin. The fragment of the gene was cloned using plasmid pZCPAB. This fragment coded for the gene with the stable expression of α-β fusion gene binding. In order to verify the exact location of the α-β fusion gene, domain plasmids were constructed. The two genes were fused into expression vector pBV221. The expressed α-β fusion protein was identified by ELISA, SDS-PAGE, Western blotting and neutralization assay.RESULTS: The protective α-toxin gene (cpa906) and the β-toxin gene (cpb930) were obtained. The recombinant plasmid pZCPAB carrying α-β fusion gene was constructed and transformed into BL21(DE3). The recombinant strain BL21(DE3)(pZCPAB) was obtained. After the recombinant strain BL21(DE3)(pZCPAB) was induced by 42℃, its expressed product was about 22.14% of total cellular protein at SDS-PAGE and thin-layer gel scanning analysis. Neutralization assay indicated that the antibody induced by immunization with α-β fusion protein could neutralize the toxicity of α-toxin and β-toxin.CONCLUSION: The obtained α-toxin and β-toxin genes are correct. The recombinant strain BL21(DE3)(pZCPAB)could produce α-β fusion protein. This protein can be used for immunization and is immunogenic. The antibody induced by immunization with α-β fusion protein could neutralize the toxicity of α-toxin and β-toxin.

  15. Mutant with diphtheria toxin receptor and acidification function but defective in entry of toxin

    Energy Technology Data Exchange (ETDEWEB)

    Kohno, Kenji (National Institute for Basic Biology, Aichi (Japan)); Hayes, H.; Mekada, Eisuke (Osaka Univ. (Japan)); Uchida, Tsuyoshi (National Institute for Basic Biology, Aichi (Japan) Osaka Univ. (Japan))

    1987-09-01

    A mutant of Chinese hamster ovary cells, GE1, that is highly resistant to diphtheria toxin was isolated. The mutant contains 50% ADP-ribosylatable elongation factor 2, but its protein synthesis was not inhibited by the toxin even at concentrations above 100 {mu}g/ml. {sup 125}I-labeled diphtheria toxin was associated with GE1 cells as well as with the parent cells but did not block protein synthesis of GE1 cells even when the cells were exposed to low pH in the presence or absence of NH{sub 4}Cl. The infections of GE1 cells and the parent cells by vesicular stomatitis virus were similar. GE1 cells were cross-resistant to Pseudomonas aeruginosa exotoxin A and so were about 1,000 times more resistant to this toxin than the parent cells. Hybrids of GE1 cells and the parent cells or mutant cells lacking a functional receptor were more sensitive to diphtheria toxin than GE1 cells. These results suggest that entry of diphtheria toxin into cells requires a cellular factor(s) in addition to those involved in receptor function and acidification of endosomes and that GE1 cells do not express this cellular factor. This character is recessive in GE1 cells.

  16. Clostridium Perfringens Toxins Involved in Mammalian Veterinary Diseases

    OpenAIRE

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

    2010-01-01

    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 r...

  17. Differentially expressed genes in adrenal gland of H22 liver cancer mice with different syndromes and in different stages

    Directory of Open Access Journals (Sweden)

    Zhi-qiang PAN

    2008-08-01

    Full Text Available Objective: To reveal the characteristics of gene expression in adrenal gland of H22 tumor mice with typical syndromes and in different liver cancer stages. Methods: By the quantitative four diagnosis and syndrome differentiation methods and GeneChip Mouse Exon 1.0 ST Array, we observed adrenal gland gene expression in H22 tumor mice with pathogenic factor-toxin predominance syndrome and qi deficiency syndrome in the earlier stage, yang-qi deficiency syndrome in the intermediate stage, and qi-yin-yang deficiency syndrome in the advanced stage. Genes highly expressed and remarkably different were analyzed in this study. Results: A total of seventy-three up-regulated coincident genes and twenty-six down-regulated coincident genes in different stages were investigated in the study. Up-regulated coincident genes included Hp, C3, Anxa1, Procr, C2, Il4ra, Cd14, Ptprc, Cd52, C4b, Eno3, Xdh, Gpx3, and so on. Down-regulated coincident genes included nervous system function-related genes such as Plp1, Mbp, Aldh1a1, Cck, Atn1, genes associated with electrolyte metabolism such as Aldh1a1 and Slc22a17, genes related to signal transduction such as Cxcr4, Spag5 and Stmn3, etc, and genes related to transcriptional control and protein biosynthesis such as Hspa1a, Dnajb1, Thra, Hhex and so on.Conclusion: With the development of the tumorigenesis, the symptoms and signs and differentially expressed genes in adrenal gland of H22 tumor mice can be measured. Up-regulated and down-regulated coincident genes may be the features of H22 tumor mice different from those of normal mice.

  18. Campylobacter spp.isolation, its toxin genes detection and molecular subtyping in diarrhea patients in Shanghai in 2014%上海市2014年腹泻患者弯曲菌分离、毒力基因检测及分子分型结果

    Institute of Scientific and Technical Information of China (English)

    屠丽红; 陈洪友; 陈敏

    2015-01-01

    [目的] 了解上海市2014年腹泻患者中弯曲菌感染现状,并分析弯曲菌的毒力基因及分子分型特征.[方法] 采用膜过滤法对2014年上海市2 235例腹泻患者肛拭标本进行弯曲菌检测,并用常规生化试验和PCR方法鉴定分离菌株. 采用PCR检测弯曲菌分离株的6种毒力相关基因,包括鞭毛蛋白基因flaA,细胞溶涨毒素cdt基因簇cdtA、cdtB、cdtC,pVir质粒virB同源性基因virB11,外膜蛋白基因cadF. 采用脉冲场凝胶电泳(PFGE)法对弯曲菌分离株进行分子分型. [结果] 2 235例腹泻患者的肛拭标本中共检出弯曲菌43株,阳性率为1.9%. 其中空肠弯曲菌占95.3%(41/43),结肠弯曲菌占4.7%(2/43). 毒力相关基因检测显示,100.0%(43/43)的弯曲菌菌株flaA基因和cadF基因阳性,93.0%(40/43)的弯曲菌菌株cdtA基因和cdtB基因阳性,88.4%(38/43)的弯曲菌菌株cdtC基因阳性,只有7.0%(3/43)的弯曲菌菌株virB11基因阳性. 43株弯曲菌经PFGE分型,共分为6个聚类. [结论]上海市腹泻患者中分离的弯曲菌普遍存在flaA和cadF基因,cdtA、cdtB、cdtC基因携带率高,virB11携带率略低. 弯曲菌分子分型呈多样化和复杂化特征,其引起的腹泻以散发为主.%[ Objective] To investigate the status quo of Campylobacter spp.infection in Shanghai and study its molecular characteristics and virulence and toxin genes. [ Methods ] Stool samples collected from diarrheal patients were cultured for bacterial pathogens using membrane filter method.The strains were identified by biochemical tests and PCR.PCR was applied to detect six virulence and toxin genes including flaA,cdtA,cdtB,cdtC,virB11,cadF.Pulsed-field gel electrophoresis ( PFGE) was carried out for subtyping. [Results] A total of 43 Campylobacter spp.(1.9%) were collected from 2 235 stool samples in Shanghai in 2014 including 41 Campylobacter jejuni isolates(95.3%) and 2 Campylobacter coli isolates(4.7%) .The data showed 100.0%(43/43) of the isolates were

  19. Site-directed mutagenesis of the heterotrimeric killer toxin zymocin identifies residues required for early steps in toxin action.

    Science.gov (United States)

    Wemhoff, Sabrina; Klassen, Roland; Meinhardt, Friedhelm

    2014-10-01

    Zymocin is a Kluyveromyces lactis protein toxin composed of αβγ subunits encoded by the cytoplasmic virus-like element k1 and functions by αβ-assisted delivery of the anticodon nuclease (ACNase) γ into target cells. The toxin binds to cells' chitin and exhibits chitinase activity in vitro that might be important during γ import. Saccharomyces cerevisiae strains carrying k1-derived hybrid elements deficient in either αβ (k1ORF2) or γ (k1ORF4) were generated. Loss of either gene abrogates toxicity, and unexpectedly, Orf2 secretion depends on Orf4 cosecretion. Functional zymocin assembly can be restored by nuclear expression of k1ORF2 or k1ORF4, providing an opportunity to conduct site-directed mutagenesis of holozymocin. Complementation required active site residues of α's chitinase domain and the sole cysteine residue of β (Cys250). Since βγ are reportedly disulfide linked, the requirement for the conserved γ C231 was probed. Toxicity of intracellularly expressed γ C231A indicated no major defect in ACNase activity, while complementation of k1ΔORF4 by γ C231A was lost, consistent with a role of β C250 and γ C231 in zymocin assembly. To test the capability of αβ to carry alternative cargos, the heterologous ACNase from Pichia acaciae (P. acaciae Orf2 [PaOrf2]) was expressed, along with its immunity gene, in k1ΔORF4. While efficient secretion of PaOrf2 was detected, suppression of the k1ΔORF4-derived k1Orf2 secretion defect was not observed. Thus, the dependency of k1Orf2 on k1Orf4 cosecretion needs to be overcome prior to studying αβ's capability to deliver other cargo proteins into target cells. PMID:25128337

  20. Cloning and heterologous expression of a novel insecticidal gene (tccC1) from Xenorhabdus nematophilus strain

    International Nuclear Information System (INIS)

    We have identified and cloned a novel toxin gene (tccC1/xptB1) from Xenorhabdus nematophilus strain isolated from Korea-specific entomophagous nematode Steinernema glaseri MK. The DNA sequence of cloned toxin gene (3048 bp) has an open reading frame encoding 1016 amino acids with a predicted molecular mass of 111058 Da. The toxin sequence shares 50-96% identical amino acid residues with the previously reported tccC1 cloned from X. nematophilus (AJ308438), Photorhabdus luminescens W14 (AF346499) P. luminescens TTO1 (BX571873), and Yersinia pestis CO92 (NC003143). The toxin gene was successfully expressed in Escherichia coli, and the recombinant toxin protein caused a rapid cessation in mortality of Galleria mellonella larvae (80% death of larvae within 2 days). Conclusively, the heterologous expression of the novel gene tccC1 cloned into E. coli plasmid vector produced recombinant toxin with high insecticidal activity