Epinephrine auto-injection radically increases risk for clostridial infection and necrotizing fasciitis

Directory of Open Access Journals (Sweden)

Kenneth Larson

2017-04-01

Full Text Available Clostridial perfringens is a bacteria commonly found on skin flora. Due to the optimal growth environment intramuscular epinephrine injections predispose patients to the rapid development of clostridial myonecrosis. There have been only four cases, including this one, reported in the last 60 years of pediatric Clostridium perfringens infections post-epinephrine injection. We detail the successful management of a 16 year old, immunocompetent female who developed gas gangrene and necrotizing fasciitis on her thigh secondary to clostridial infection after utilization of an Epinephrine Auto-Injector and review the pediatric literature of patients with Clostridial perfringens secondary to epinephrine injection. We define common clinical signs and symptoms of clostridial infection from the review of the literature. The relevance of our findings is to raise awareness among emergency physicians when patients present following an injection in order to reduce diagnostic delay that could result in amputation or death.

Clostridial Binary Toxins: Iota and C2 Family Portraits

Science.gov (United States)

Stiles, Bradley G.; Wigelsworth, Darran J.; Popoff, Michel R.; Barth, Holger

2011-01-01

There are many pathogenic Clostridium species with diverse virulence factors that include protein toxins. Some of these bacteria, such as C. botulinum, C. difficile, C. perfringens, and C. spiroforme, cause enteric problems in animals as well as humans. These often fatal diseases can partly be attributed to binary protein toxins that follow a classic AB paradigm. Within a targeted cell, all clostridial binary toxins destroy filamentous actin via mono-ADP-ribosylation of globular actin by the A component. However, much less is known about B component binding to cell-surface receptors. These toxins share sequence homology amongst themselves and with those produced by another Gram-positive, spore-forming bacterium also commonly associated with soil and disease: Bacillus anthracis. This review focuses upon the iota and C2 families of clostridial binary toxins and includes: (1) basics of the bacterial source; (2) toxin biochemistry; (3) sophisticated cellular uptake machinery; and (4) host–cell responses following toxin-mediated disruption of the cytoskeleton. In summary, these protein toxins aid diverse enteric species within the genus Clostridium. PMID:22919577

Independent evolution of neurotoxin and flagellar genetic loci in proteolytic Clostridium botulinum.

Science.gov (United States)

Carter, Andrew T; Paul, Catherine J; Mason, David R; Twine, Susan M; Alston, Mark J; Logan, Susan M; Austin, John W; Peck, Michael W

2009-03-19

Proteolytic Clostridium botulinum is the causative agent of botulism, a severe neuroparalytic illness. Given the severity of botulism, surprisingly little is known of the population structure, biology, phylogeny or evolution of C. botulinum. The recent determination of the genome sequence of C. botulinum has allowed comparative genomic indexing using a DNA microarray. Whole genome microarray analysis revealed that 63% of the coding sequences (CDSs) present in reference strain ATCC 3502 were common to all 61 widely-representative strains of proteolytic C. botulinum and the closely related C. sporogenes tested. This indicates a relatively stable genome. There was, however, evidence for recombination and genetic exchange, in particular within the neurotoxin gene and cluster (including transfer of neurotoxin genes to C. sporogenes), and the flagellar glycosylation island (FGI). These two loci appear to have evolved independently from each other, and from the remainder of the genetic complement. A number of strains were atypical; for example, while 10 out of 14 strains that formed type A1 toxin gave almost identical profiles in whole genome, neurotoxin cluster and FGI analyses, the other four strains showed divergent properties. Furthermore, a new neurotoxin sub-type (A5) has been discovered in strains from heroin-associated wound botulism cases. For the first time, differences in glycosylation profiles of the flagella could be linked to differences in the gene content of the FGI. Proteolytic C. botulinum has a stable genome backbone containing specific regions of genetic heterogeneity. These include the neurotoxin gene cluster and the FGI, each having evolved independently of each other and the remainder of the genetic complement. Analysis of these genetic components provides a high degree of discrimination of strains of proteolytic C. botulinum, and is suitable for clinical and forensic investigations of botulism outbreaks.

Independent evolution of neurotoxin and flagellar genetic loci in proteolytic Clostridium botulinum

Directory of Open Access Journals (Sweden)

Twine Susan M

2009-03-01

Full Text Available Abstract Background Proteolytic Clostridium botulinum is the causative agent of botulism, a severe neuroparalytic illness. Given the severity of botulism, surprisingly little is known of the population structure, biology, phylogeny or evolution of C. botulinum. The recent determination of the genome sequence of C. botulinum has allowed comparative genomic indexing using a DNA microarray. Results Whole genome microarray analysis revealed that 63% of the coding sequences (CDSs present in reference strain ATCC 3502 were common to all 61 widely-representative strains of proteolytic C. botulinum and the closely related C. sporogenes tested. This indicates a relatively stable genome. There was, however, evidence for recombination and genetic exchange, in particular within the neurotoxin gene and cluster (including transfer of neurotoxin genes to C. sporogenes, and the flagellar glycosylation island (FGI. These two loci appear to have evolved independently from each other, and from the remainder of the genetic complement. A number of strains were atypical; for example, while 10 out of 14 strains that formed type A1 toxin gave almost identical profiles in whole genome, neurotoxin cluster and FGI analyses, the other four strains showed divergent properties. Furthermore, a new neurotoxin sub-type (A5 has been discovered in strains from heroin-associated wound botulism cases. For the first time, differences in glycosylation profiles of the flagella could be linked to differences in the gene content of the FGI. Conclusion Proteolytic C. botulinum has a stable genome backbone containing specific regions of genetic heterogeneity. These include the neurotoxin gene cluster and the FGI, each having evolved independently of each other and the remainder of the genetic complement. Analysis of these genetic components provides a high degree of discrimination of strains of proteolytic C. botulinum, and is suitable for clinical and forensic investigations of botulism

Improved n-butanol production via co-expression of membrane-targeted tilapia metallothionein and the clostridial metabolic pathway in Escherichia coli.

Science.gov (United States)

Chin, Wei-Chih; Lin, Kuo-Hsing; Liu, Chun-Chi; Tsuge, Kenji; Huang, Chieh-Chen

2017-04-11

N-Butanol has favorable characteristics for use as either an alternative fuel or platform chemical. Bio-based n-butanol production using microbes is an emerging technology that requires further development. Although bio-industrial microbes such as Escherichia coli have been engineered to produce n-butanol, reactive oxygen species (ROS)-mediated toxicity may limit productivity. Previously, we show that outer-membrane-targeted tilapia metallothionein (OmpC-TMT) is more effective as an ROS scavenger than human and mouse metallothioneins to reduce oxidative stress in the host cell. The host strain (BUT1-DE) containing the clostridial n-butanol pathway displayed a decreased growth rate and limited n-butanol productivity, likely due to ROS accumulation. The clostridial n-butanol pathway was co-engineered with inducible OmpC-TMT in E. coli (BUT3-DE) for simultaneous ROS removal, and its effect on n-butanol productivity was examined. The ROS scavenging ability of cells overexpressing OmpC-TMT was examined and showed an approximately twofold increase in capacity. The modified strain improved n-butanol productivity to 320 mg/L, whereas the control strain produced only 95.1 mg/L. Transcriptomic analysis revealed three major KEGG pathways that were significantly differentially expressed in the BUT3-DE strain compared with their expression in the BUT1-DE strain, including genes involved in oxidative phosphorylation, fructose and mannose metabolism and glycolysis/gluconeogenesis. These results indicate that OmpC-TMT can increase n-butanol production by scavenging ROS. The transcriptomic analysis suggested that n-butanol causes quinone malfunction, resulting in oxidative-phosphorylation-related nuo operon downregulation, which would diminish the ability to convert NADH to NAD + and generate proton motive force. However, fructose and mannose metabolism-related genes (fucA, srlE and srlA) were upregulated, and glycolysis/gluconeogenesis-related genes (pfkB, pgm) were

CD44 Promotes intoxication by the clostridial iota-family toxins.

Science.gov (United States)

Wigelsworth, Darran J; Ruthel, Gordon; Schnell, Leonie; Herrlich, Peter; Blonder, Josip; Veenstra, Timothy D; Carman, Robert J; Wilkins, Tracy D; Van Nhieu, Guy Tran; Pauillac, Serge; Gibert, Maryse; Sauvonnet, Nathalie; Stiles, Bradley G; Popoff, Michel R; Barth, Holger

2012-01-01

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

Metabolomics of Clostridial Biofuel Production

Energy Technology Data Exchange (ETDEWEB)

Rabinowitz, Joshua D [Princeton Univ., NJ (United States); Aristilde, Ludmilla [Cornell Univ., Ithaca, NY (United States); Amador-Noguez, Daniel [Univ. of Wisconsin, Madison, WI (United States)

2015-09-08

Members of the genus Clostridium collectively have the ideal set of the metabolic capabilities for fermentative biofuel production: cellulose degradation, hydrogen production, and solvent excretion. No single organism, however, can effectively convert cellulose into biofuels. Here we developed, using metabolomics and isotope tracers, basic science knowledge of Clostridial metabolism of utility for future efforts to engineer such an organism. In glucose fermentation carried out by the biofuel producer Clostridium acetobutylicum, we observed a remarkably ordered series of metabolite concentration changes as the fermentation progressed from acidogenesis to solventogenesis. In general, high-energy compounds decreased while low-energy species increased during solventogenesis. These changes in metabolite concentrations were accompanied by large changes in intracellular metabolic fluxes, with pyruvate directed towards acetyl-CoA and solvents instead of oxaloacetate and amino acids. Thus, the solventogenic transition involves global remodeling of metabolism to redirect resources from biomass production into solvent production. In contrast to C. acetobutylicum, which is an avid fermenter, C. cellulolyticum metabolizes glucose only slowly. We find that glycolytic intermediate concentrations are radically different from fast fermenting organisms. Associated thermodynamic and isotope tracer analysis revealed that the full glycolytic pathway in C. cellulolyticum is reversible. This arises from changes in cofactor utilization for phosphofructokinase and an alternative pathway from phosphoenolpyruvate to pyruvate. The net effect is to increase the high-energy phosphate bond yield of glycolysis by 150% (from 2 to 5) at the expense of lower net flux. Thus, C. cellulolyticum prioritizes glycolytic energy efficiency over speed. Degradation of cellulose results in other sugars in addition to glucose. Simultaneous feeding of stable isotope-labeled glucose and unlabeled pentose sugars

Toxicology and detection methods of the alkaloid neurotoxin produced by cyanobacteria, anatoxin-a.

Science.gov (United States)

Osswald, Joana; Rellán, Sandra; Gago, Ana; Vasconcelos, Vitor

2007-11-01

Freshwater resources are under stress due to naturally occurring conditions and human impacts. One of the consequences is the proliferation of cyanobacteria, microphytoplankton organisms that are capable to produce toxins called cyanotoxins. Anatoxin-a is one of the main cyanotoxins. It is a very potent neurotoxin that was already responsible for some animal fatalities. In this review we endeavor to divulgate much of the internationally published information about toxicology, occurrence and detection methods of anatoxin-a. Cyanobacteria generalities, anatoxin-a occurrence and production as well as anatoxin-a toxicology and its methods of detection are the aspects focused in this review. Remediation of anatoxin-a occurrence will be addressed with a public health perspective. Final remarks call the attention for some important gaps in the knowledge about this neurotoxin and its implication to public health. Alterations of aquatic ecosystems caused by anatoxin-a is also addressed. Although anatoxin-a is not the more frequent cyanotoxin worldwide, it has to be regarded as a health risk that can be fatal to terrestrial and aquatic organisms because of its high toxicity.

Mechanisms of microbial oil recovery by Clostridium acetobutylicum and Bacillus strain JF-2

Energy Technology Data Exchange (ETDEWEB)

Marsh, T.L.; Zhang, X.; Knapp, R.M.; McInerney, M.J.; Sharma, P.K.; Jackson, B.E.

1995-12-31

Core displacement experiments at elevated pressures were conducted to determine whether microbial processes are effective under conditions that simulate those found in an actual oil reservoir. The in-situ growth of Clostridium acetobutylicum and Bacillus strain JF-2 resulted in the recovery of residual oil. About 21 and 23% of the residual oil was recovered by C. acetobutylicum and Bacillus strain JF-2, respectively. Flooding cores with cell-free culture fluids of C. acetobutylicum with and without the addition of 50 mM acetone and 100 mM butanol did not result in the recovery of residual oil. Mathematical simulations showed that the amount of gas produced by the clostridial fermentation was not showed that the amount of gas produced by the clostridial fermentation was not sufficient to recover residual oil. Oil recovery by Bacillus strain JF-2 was highly correlated to surfactant production. A biosurfactant-deficient mutant of strain JF-2 was not capable of recovering residual oil. These data show that surfactant production is an important mechanism for microbially enhanced oil recovery. The mechanism for oil recovery by C. acetobutylicum is not understood at this time, but the production of acids, solvents, or gases alone cannot explain the observed increases in oil recovery by this organism.

Characterization and Ecology of Carboxymethylcellulase-Producing Anaerobic Bacterial Communities Associated with the Intestinal Tract of the Pinfish, Lagodon rhomboides

OpenAIRE

Stellwag, E. J.; Smith, T. D.; Luczkovich, J. J.

1995-01-01

Carboxymethylcellulase (CMCase)-producing obligate anaerobes were isolated from the intestinal tract contents but not the feeding habitat of seagrass-consuming pinfish. Taxonomic characterization of these CMCase-producing strains revealed four taxonomic clusters; three were clostridial and one was of unknown taxonomic affinity. Our results demonstrated that the CMCase-producing obligate anaerobe community from pinfish differed from functionally similar microbial communities in terrestrial her...

Historical Perspectives and Guidelines for Botulinum Neurotoxin Subtype Nomenclature

Science.gov (United States)

2016-08-26

Each neurotoxin subtype within a serotype cleaves its target substrate at the same single conserved peptide bond, except for BoNT/F5 (Table 2) [55...common for strains of C. botulinum Group III to form a chimeric or hybrid protein that combines elements of BoNT/C and BoNT/D neurotoxin, rather than a...Approved for public release; distribution is unlimited. UNCLASSIFIED 15 reported as BoNT/CD or BoNT/DC chimeric toxins [22]. Two exotoxins

Reutericyclin producing Lactobacillus reuteri modulates development of fecal microbiota in weanling pigs

Directory of Open Access Journals (Sweden)

Yan eYang

2015-07-01

Full Text Available Lactobacillus reuteri is used as probiotic culture in food and feed applications; however, strain specific properties of L. reuteri that mediate probiotic activity remain unknown. This study aimed to determine effects of feed fermentation with exopolysaccharide and reutericyclin producing L. reuteri on the transition of the gut microbiome of piglets after weaning. The reutericyclin and reuteran producing L. reuteri TMW1.656 was compared to the reutericyclin negative and levan producing L. reuteri LTH5794 and unfermented controls. Both strains were fermented at conditions supporting exopolysaccharide formation, or at conditions not supporting exopolysaccharide formation. Fecal microbiota were characterized by partial sequencing of 16S rRNA genes, and by quantitative PCR targeting clostridial toxins. The transition to solid food resulted in a transient increase of Proteobacteria to 12% of total bacteria, and increased bacterial diversity by increasing the abundance of anaerobic fibre fermenting Firmicutes. Three weeks after weaning, Prevotella and Lactobacillus were among the dominant bacterial genera. Feed fermentation with L. reuteri affected the abundance of few bacterial taxa and particularly reduced the abundance of Enterobacteriaceae (P<0.05 when compared to unfermented controls. Reutericyclin producing L. reuteri increased the abundance of Dialister spp. and Mitsuokella spp. (P<0.05 but did not influence the abundance of clostridial toxins in the feces. In conclusion, data on the contribution of specific metabolic activities of L. reuteri to probiotic activity will facilitate the strain selection for probiotic applications in food and feed.

Neuronal Functions Associated with Endo- and Exocytotic Events-cum-Molecular Trafficking May Be Cell Maturation-Dependent: Lessons Learned from Studies on Botulism

Science.gov (United States)

2011-01-01

Clostridium botulinum type A progenitor toxins . Infect Immun 64:1589–1594 Li L, Singh BR (1999) Structure -function relationship of clostridial...experimental design and demonstration of the validity of the targeted neurologic therapeutic delivery approach based on recombinant botulinum toxin ...Endocytosis Exocytosis Molecular trafficking Cell maturation Botulism Targeted therapeutic Background Botulinum neurotoxins (BoNTs) are produced by

Effects of algal-produced neurotoxins on metabolic activity in telencephalon, optic tectum and cerebellum of Atlantic salmon (Salmo salar)

International Nuclear Information System (INIS)

Bakke, Marit Jorgensen; Horsberg, Tor Einar

2007-01-01

Neurotoxins from algal blooms have been reported to cause mortality in a variety of species, including sea birds, sea mammals and fish. Farmed fish cannot escape harmful algal blooms and their potential toxins, thus they are more vulnerable for exposure than wild stocks. Sublethal doses of the toxins are likely to affect fish behaviour and may impair cognitive abilities. In the present study, changes in the metabolic activity in different parts of the Atlantic salmon (Salmo salar) brain involved in central integration and cognition were investigated after exposure to sublethal doses of three algal-produced neurotoxins; saxitoxin (STX), brevetoxin (BTX) and domoic acid (DA). Fish were randomly selected to four groups for i.p. injection of saline (control) or one of the neurotoxins STX (10 μg STX/kg bw), BTX (68 μg BTX/kg bw) or DA (6 mg DA/kg bw). In addition, 14 C-2-deoxyglucose was i.m. injected to measure brain metabolic activity by autoradiography. The three regions investigated were telencephalon (Tel), optic tectum (OT) and cerebellum (Ce). There were no differences in the metabolic activity after STX and BTX exposure compared to the control in these regions. However, a clear increase was observed after DA exposure. When the subregions with the highest metabolic rate were pseudocoloured in the three brain regions, the three toxins caused distinct differences in the respective patterns of metabolic activation. Fish exposed to STX displayed similar patterns as the control fish, whereas fish exposed to BTX and DA showed highest metabolic activity in subregions different from the control group. All three neurotoxins affected subregions that are believed to be involved in cognitive abilities in fish

Construction of a nontoxigenic Clostridium botulinum strain for food challenge studies.

Science.gov (United States)

Bradshaw, Marite; Marshall, Kristin M; Heap, John T; Tepp, William H; Minton, Nigel P; Johnson, Eric A

2010-01-01

Clostridium botulinum produces the most poisonous natural toxin known and is a perennial concern to the food industry and to regulatory agencies due to the potential threat of food-borne botulism. To ensure the botulinal safety of foods, rigorous food challenge testing to validate food-processing conditions and food formulations has been routinely performed. Detection of the botulinum neurotoxin is performed by using a mouse bioassay and/or in vitro assays. There has been considerable interest by the food industry and regulatory agencies in minimizing or even replacing the use of animals in these challenge studies. In addition, due to stringent select-agent regulations, the testing of various foods using toxigenic C. botulinum strains requires facilities and personnel that are certified for work with this organism. For this purpose we propose to generate sets of nontoxigenic C. botulinum strains from proteolytic and nonproteolytic groups that differ from the wild-type strains only by their inability to produce botulinum neurotoxin. In this initial study we describe the generation of a nontoxigenic mutant of C. botulinum strain 62A using the ClosTron mutagenesis system by inserting a group II intron into the botulinum neurotoxin type A gene (bont/A). The mutant clones were nontoxigenic as determined by Western blots and mouse bioassays but showed physiological characteristics, including growth properties and sporulation, that were similar to those of the parent strain in laboratory media. Additional studies will be required to evaluate comparable characteristics in various food matrices. The availability of suitable nontoxigenic C. botulinum strains for food challenge studies will be beneficial for enhancing the botulinal safety of foods as well as increasing the biosafety of workers and may eliminate the use of laboratory animals.

Protein Domain Analysis of C. botulinum Type A Neurotoxin and Its Relationship with Other Botulinum Serotypes

OpenAIRE

Sharma, Shashi K.; Basavanna, Uma; Shukla, Hem D.

2009-01-01

Botulinum neurotoxins (BoNTs) are highly potent poisons produced by seven serotypes of Clostridium botulinum. The mechanism of neurotoxin action is a multistep process which leads to the cleavage of one of three different SNARE proteins essential for synaptic vesicle fusion and transmission of the nerve signals to muscles: synaptobrevin, syntaxin, or SNAP-25. In order to understand the precise mechanism of neurotoxin in a host, the domain structure of the neurotoxin was analyzed among differe...

Antipruritic effects of botulinum neurotoxins

DEFF Research Database (Denmark)

Gazerani, Parisa

2018-01-01

This review explores current evidence to demonstrate that botulinum neurotoxins (BoNTs) exert antipruritic effects. Both experimental and clinical conditions in which botulinum neurotoxins have been applied for pruritus relief will be presented and significant findings will be highlighted. Potent....... Potential mechanisms underlying antipruritic effects will also be discussed and ongoing challenges and unmet needs will be addressed.......This review explores current evidence to demonstrate that botulinum neurotoxins (BoNTs) exert antipruritic effects. Both experimental and clinical conditions in which botulinum neurotoxins have been applied for pruritus relief will be presented and significant findings will be highlighted...

Management of a femoral fracture complicated by clostridial myositis

International Nuclear Information System (INIS)

Thomson, M.J.; Eger, C.E.

1997-01-01

A clinical case of clostridial myositis secondary to a comminuted femoral fracture is described. This case is unusual because, despite the severe degree of obvious muscle necrosis and gas production, the dog had minimal signs of systemic toxicity. Union of the fracture was achieved but six months postoperatively muscular contracture had resulted in permanent stifle extension

Neurotoxins from Marine Dinoflagellates: A Brief Review

Directory of Open Access Journals (Sweden)

Da-Zhi Wang

2008-06-01

Full Text Available Dinoflagellates are not only important marine primary producers and grazers, but also the major causative agents of harmful algal blooms. It has been reported that many dinoflagellate species can produce various natural toxins. These toxins can be extremely toxic and many of them are effective at far lower dosages than conventional chemical agents. Consumption of seafood contaminated by algal toxins results in various seafood poisoning syndromes: paralytic shellfish poisoning (PSP, neurotoxic shellfish poisoning (NSP, amnesic shellfish poisoning (ASP, diarrheic shellfish poisoning (DSP, ciguatera fish poisoning (CFP and azaspiracid shellfish poisoning (ASP. Most of these poisonings are caused by neurotoxins which present themselves with highly specific effects on the nervous system of animals, including humans, by interfering with nerve impulse transmission. Neurotoxins are a varied group of compounds, both chemically and pharmacologically. They vary in both chemical structure and mechanism of action, and produce very distinct biological effects, which provides a potential application of these toxins in pharmacology and toxicology. This review summarizes the origin, structure and clinical symptoms of PSP, NSP, CFP, AZP, yessotoxin and palytoxin produced by marine dinoflagellates, as well as their molecular mechanisms of action on voltage-gated ion channels.

Structural and mutational analyses of the receptor binding domain of botulinum D/C mosaic neurotoxin: Insight into the ganglioside binding mechanism

Energy Technology Data Exchange (ETDEWEB)

Nuemket, Nipawan [Graduate School of Life Sciences, Hokkaido University, Sapporo 060-0810 (Japan); Tanaka, Yoshikazu [Creative Research Institution ' Sousei,' Hokkaido University, Sapporo 001-0021 (Japan); Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810 (Japan); Tsukamoto, Kentaro; Tsuji, Takao [Department of Microbiology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192 (Japan); Nakamura, Keiji; Kozaki, Shunji [Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 598-8531 (Japan); Yao, Min [Graduate School of Life Sciences, Hokkaido University, Sapporo 060-0810 (Japan); Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810 (Japan); Tanaka, Isao, E-mail: tanaka@castor.sci.hokudai.ac.jp [Graduate School of Life Sciences, Hokkaido University, Sapporo 060-0810 (Japan); Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810 (Japan)

2011-07-29

Highlights: {yields} We determined the crystal structure of the receptor binding domain of BoNT in complex with 3'-sialyllactose. {yields} An electron density derived from the 3'-sialyllactose was confirmed at the cleft in the C-terminal subdomain. {yields} Alanine site-directed mutagenesis showed that GBS and GBL are important for ganglioside binding. {yields} A cell binding mechanism, which involves cooperative contribution of two sites, was proposed. -- Abstract: Clostridium botulinum type D strain OFD05, which produces the D/C mosaic neurotoxin, was isolated from cattle killed by the recent botulism outbreak in Japan. The D/C mosaic neurotoxin is the most toxic of the botulinum neurotoxins (BoNT) characterized to date. Here, we determined the crystal structure of the receptor binding domain of BoNT from strain OFD05 in complex with 3'-sialyllactose at a resolution of 3.0 A. In the structure, an electron density derived from the 3'-sialyllactose was confirmed at the cleft in the C-terminal subdomain. Alanine site-directed mutagenesis showed the significant contribution of the residues surrounding the cleft to ganglioside recognition. In addition, a loop adjoining the cleft also plays an important role in ganglioside recognition. In contrast, little effect was observed when the residues located around the surface previously identified as the protein receptor binding site in other BoNTs were substituted. The results of cell binding analysis of the mutants were significantly correlated with the ganglioside binding properties. Based on these observations, a cell binding mechanism of BoNT from strain OFD05 is proposed, which involves cooperative contribution of two ganglioside binding sites.

Peg Precipitation Coupled with Chromatography is a New and Sufficient Method for the Purification of Botulinum Neurotoxin Type B

Science.gov (United States)

Zhao, Yao; Kang, Lin; Gao, Shan; Gao, Xing; Xin, Wenwen; Wang, Jinglin

2012-01-01

Clostridium botulinum neurotoxins are used to treat a variety of neuro-muscular disorders, as well as in cosmetology. The increased demand requires efficient methods for the production and purification of these toxins. In this study, a new purification process was developed for purifying type B neurotoxin. The kinetics of C.botulinum strain growth and neurotoxin production were determined for maximum yield of toxin. The neurotoxin was purified by polyethylene glycol (PEG) precipitation and chromatography. Based on design of full factorial experiment, 20% (w/v) PEG-6000, 4°C, pH 5.0 and 0.3 M NaCl were optimal conditions to obtain a high recovery rate of 87% for the type B neurotoxin complex, as indicated by a purification factor of 61.5 fold. Furthermore, residual bacterial cells, impurity proteins and some nucleic acids were removed by PEG precipitation. The following purification of neurotoxin was accomplished by two chromatography techniques using Sephacryl™ S-100 and phenyl HP columns. The neurotoxin was recovered with an overall yield of 21.5% and the purification factor increased to 216.7 fold. In addition, a mouse bioassay determined the purified neurotoxin complex possessed a specific toxicity (LD50) of 4.095 ng/kg. PMID:22761863

Neurotoxin synthesis is positively regulated by the sporulation transcription factor Spo0A in Clostridium botulinum type E.

Science.gov (United States)

Mascher, Gerald; Mertaoja, Anna; Korkeala, Hannu; Lindström, Miia

2017-10-01

Clostridium botulinum produces the most potent natural toxin, the botulinum neurotoxin (BoNT), probably to create anaerobiosis and nutrients by killing the host, and forms endospores that facilitate survival in harsh conditions and transmission. Peak BoNT production coincides with initiation of sporulation in C. botulinum cultures, which suggests common regulation. Here, we show that Spo0A, the master regulator of sporulation, positively regulates BoNT production. Insertional inactivation of spo0A in C. botulinum type E strain Beluga resulted in significantly reduced BoNT production and in abolished or highly reduced sporulation in relation to wild-type controls. Complementation with spo0A restored BoNT production and sporulation. Recombinant DNA-binding domain of Spo0A directly bound to a putative Spo0A-binding box (CTTCGAA) within the BoNT/E operon promoter, demonstrating direct regulation. Spo0A is the first neurotoxin regulator reported in C. botulinum type E. Unlike other C. botulinum strains that are terrestrial and employ the alternative sigma factor BotR in directing BoNT expression, C. botulinum type E strains are adapted to aquatic ecosystems, possess distinct epidemiology and lack BotR. Our results provide fundamental new knowledge on the genetic control of BoNT production and demonstrate common regulation of BoNT production and sporulation, providing a key intervention point for control. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Tetrodotoxin, an Extremely Potent Marine Neurotoxin: Distribution, Toxicity, Origin and Therapeutical Uses

Directory of Open Access Journals (Sweden)

Jorge Lago

2015-10-01

Full Text Available Tetrodotoxin (TTX is a potent neurotoxin responsible for many human intoxications and fatalities each year. The origin of TTX is unknown, but in the pufferfish, it seems to be produced by endosymbiotic bacteria that often seem to be passed down the food chain. The ingestion of contaminated pufferfish, considered the most delicious fish in Japan, is the usual route of toxicity. This neurotoxin, reported as a threat to human health in Asian countries, has spread to the Pacific and Mediterranean, due to the increase of temperature waters worldwide. TTX, for which there is no known antidote, inhibits sodium channel producing heart failure in many cases and consequently death. In Japan, a regulatory limit of 2 mg eq TTX/kg was established, although the restaurant preparation of “fugu” is strictly controlled by law and only chefs qualified are allowed to prepare the fish. Due to its paralysis effect, this neurotoxin could be used in the medical field as an analgesic to treat some cancer pains.

Botulinum neurotoxin type A injections for vaginismus secondary to vulvar vestibulitis syndrome.

Science.gov (United States)

Bertolasi, Laura; Frasson, Emma; Cappelletti, Jee Yun; Vicentini, Silvana; Bordignon, Monia; Graziottin, Alessandra

2009-11-01

To investigate whether botulinum neurotoxin type A improves vaginismus and study its efficacy with repeated treatments. Outpatients were referred because standard cognitive-behavioral and medical treatment for vaginismus and vulvar vestibular syndrome failed. From this group, we prospectively recruited consecutive women (n=39) whose diagnostic electromyogram (EMG) recordings from the levator ani muscle showed hyperactivity at rest and reduced inhibition during straining. These women were followed for a mean (+/-standard deviation) of 105 (+/-50) weeks. Recruited patients underwent repeated cycles of botulinum neurotoxin type A injected into the levator ani under EMG guidance and EMG monitoring thereafter. At enrollment and 4 weeks after each cycle, women were asked about sexual intercourse; underwent EMG evaluation and examinations to grade vaginal resistance according to Lamont; and completed a visual analog scale (VAS) for pain, the Female Sexual Function Index Scale, a quality-of-life questionnaire (Short-Form 12 Health Survey), and bowel and bladder symptom assessment. At 4 weeks after the first botulinum neurotoxin type A cycle, the primary outcome measures (the possibility of having sexual intercourse, and levator ani EMG hyperactivity) both improved, as did the secondary outcomes, Lamont scores, VAS, Female Sexual Function Index Scales, Short-Form 12 Health Survey, and bowel-bladder symptoms. These benefits persisted through later cycles. When follow-up ended, 63.2% of the patients completely recovered from vaginismus and vulvar vestibular syndrome, 15.4% still needed reinjections (censored), and 15.4% had dropped out. Botulinum neurotoxin type A is an effective treatment option for vaginismus secondary to vulvar vestibular syndrome refractory to standard cognitive-behavioral and medical management. After patients received botulinum neurotoxin type A, their sexual activity improved and reinjections provided sustained benefits. III.

Construction of acetoin high-producing Bacillus subtilis strain

Directory of Open Access Journals (Sweden)

Yanjun Tian

2016-07-01

Full Text Available This paper describes the construction and selection of a high-producing mutant, Bacillus subtilis HB-32, with enhanced acetoin yield and productivity. The mutant was obtained by the protoplast fusion of a Bacillus subtilis mutant TH-49 (Val− producing acetoin and Bacillus licheniformis AD-30 producing α-acetolactate decarboxylase, with the fusogen polyethylene glycol and after the regeneration and selection, etc. of the fusant. The acetoin production reached 49.64 g/L, which is an increase of 61.8% compared to that of B. subtilis strain TH-49. Random amplified polymorphic DNA analysis was performed to determine the mutagenic and protoplast fusion effects and the genomic changes in the acetoin high-producing strain compared to the parent strains at the molecular level. The constructed strain was shown to be promising for large-scale acetoin production. Future studies should focus on the application of the mutant strain in practice.

Reutericyclin producing Lactobacillus reuteri modulates development of fecal microbiota in weanling pigs.

Science.gov (United States)

Yang, Yan; Zhao, Xin; Le, Minh H A; Zijlstra, Ruurd T; Gänzle, Michael G

2015-01-01

Lactobacillus reuteri is used as probiotic culture in food and feed applications; however, strain specific properties of L. reuteri that mediate probiotic activity remain unknown. This study aimed to determine effects of feed fermentation with exopolysaccharide and reutericyclin producing L. reuteri on the transition of the gut microbiome of piglets after weaning. The reutericyclin and reuteran producing L. reuteri TMW1.656 was compared to the reutericyclin negative and levan producing L. reuteri LTH5794 and unfermented controls. Both strains were fermented at conditions supporting exopolysaccharide formation, or at conditions not supporting exopolysaccharide formation. Fecal microbiota were characterized by partial sequencing of 16S rRNA genes, and by quantitative PCR targeting clostridial toxins. The transition to solid food resulted in a transient increase of Proteobacteria to 12% of total bacteria, and increased bacterial diversity by increasing the abundance of anaerobic fiber fermenting Firmicutes. Three weeks after weaning, Prevotella and Lactobacillus were among the dominant bacterial genera. Feed fermentation with L. reuteri affected the abundance of few bacterial taxa and particularly reduced the abundance of Enterobacteriaceae (P reuteri increased the abundance of Dialister spp. and Mitsuokella spp. (P reuteri to probiotic activity will facilitate the strain selection for probiotic applications in food and feed.

Heat shock and prolonged heat stress attenuate neurotoxin and sporulation gene expression in group I Clostridium botulinum strain ATCC 3502.

Science.gov (United States)

Selby, Katja; Mascher, Gerald; Somervuo, Panu; Lindström, Miia; Korkeala, Hannu

2017-01-01

Foodborne pathogenic bacteria are exposed to a number of environmental stresses during food processing, storage, and preparation, and in the human body. In order to improve the safety of food, the understanding of molecular stress response mechanisms foodborne pathogens employ is essential. Many response mechanisms that are activated during heat shock may cross-protect bacteria against other environmental stresses. To better understand the molecular mechanisms Clostridium botulinum, the causative agent of botulism, utilizes during acute heat stress and during adaptation to stressfully high temperature, the C. botulinum Group I strain ATCC 3502 was grown in continuous culture at 39°C and exposed to heat shock at 45°C, followed by prolonged heat stress at 45°C to allow adaptation of the culture to the high temperature. Growth in continuous culture was performed to exclude secondary growth phase effects or other environmental impacts on bacterial gene transcription. Changes in global gene expression profiles were studied using DNA microarray hybridization. During acute heat stress, Class I and III heat shock genes as well as members of the SOS regulon were activated. The neurotoxin gene botA and genes encoding the neurotoxin-associated proteins were suppressed throughout the study. Prolonged heat stress led to suppression of the sporulation machinery whereas genes related to chemotaxis and motility were activated. Induced expression of a large proportion of prophage genes was detected, suggesting an important role of acquired genes in the stress resistance of C. botulinum. Finally, changes in the expression of a large number of genes related to carbohydrate and amino acid metabolism indicated remodeling of the cellular metabolism.

Advanced studies of biological indirect liquefaction of coal: Topical report on Task 1: Culture identification

Energy Technology Data Exchange (ETDEWEB)

None

1989-01-01

Culture identification and characterization studies carried out at the University of Arkansas and under contract to the University of Oklahoma, Department of Botany and Microbiology, have been essentially completed. The studies indicate that the organism is indeed a new clostridial strain, to be named Clostridium ljungdahlii, strain PETC, in honor of Dr. Lars G. Ljungdahl for his work on clostridia and acetogens. C. ljungdahlii is different from other clostridial strains and similar geni in its operating conditions and choice of substrates as sole carbon and energy sources. C. ljungdahlii, strain PETC, produces ethanol as a product only at low pH levels, with acetate the primary product at higher pH levels. 46 refs., 5 figs., 6 tabs.

Methods for determining microcystins (peptide hepatotoxins) and microcystin-producing cyanobacteria.

Science.gov (United States)

Sangolkar, Lalita N; Maske, Sarika S; Chakrabarti, Tapan

2006-11-01

Episodes of cyanobacterial toxic blooms and fatalities to animals and humans due to cyanobacterial toxins (CBT) are known worldwide. The hepatotoxins and neurotoxins (cyanotoxins) produced by bloom-forming cyanobacteria have been the cause of human and animal health hazards and even death. Prevailing concentration of cell bound endotoxin, exotoxin and the toxin variants depend on developmental stages of the bloom and the cyanobacterial (CB) species involved. Toxic and non-toxic strains do not show any predictable morphological difference. The current instrumental, immunological and molecular methods applied for determining microcystins (peptide hepatotoxins) and microcystin-producing cyanobacteria are reviewed.

[New antibiotics produced by Bacillus subtilis strains].

Science.gov (United States)

Malanicheva, I A; Kozlov, D G; Efimenko, T A; Zenkova, V A; Kastrukha, G S; Reznikova, M I; Korolev, A M; Borshchevskaia, L N; Tarasova, O D; Sineokiĭ, S P; Efremenkova, O V

2014-01-01

Two Bacillus subtilis strains isolated from the fruiting body of a basidiomycete fungus Pholiota squarrosa exhibited a broad range of antibacterial activity, including those against methicillin-resistant Staphylococcus aureus INA 00761 (MRSA) and Leuconostoc mes6nteroides VKPM B-4177 resistant to glycopep-> tide antibiotics, as well as antifungal activity. The strains were identified as belonging to the "B. subtilis" com- plex based on their morphological and physiological characteristics, as well as by sequencing of the 16S rRNA gene fragments. Both strains (INA 01085 and INA 01086) produced insignificant amounts of polyene antibiotics (hexaen and pentaen, respectively). Strain INA 01086 produced also a cyclic polypeptide antibiotic containing Asp, Gly, Leu, Pro, Tyr, Thr, Trp, and Phe, while the antibiotic of strain INA 01085 contained, apart from these, two unidentified nonproteinaceous amino acids. Both polypeptide antibiotics were new compounds efficient against gram-positive bacteria and able to override the natural bacterial antibiotic resistance.

Comparative Proteome Analysis between High Lipid-Producing Strain Mucor circinelloides WJ11 and Low Lipid-Producing Strain CBS 277.49.

Science.gov (United States)

Tang, Xin; Chen, Haiqin; Gu, Zhennan; Zhang, Hao; Chen, Yong Q; Song, Yuanda; Chen, Wei

2017-06-21

Mucor circinelloides is one of few oleaginous fungi that produces a useful oil rich in γ-linolenic acid, but it usually only produces <25% total lipid. Nevertheless, we isolated a new strain WJ11 that can produce up to 36% lipid of cell dry weight. In this study, we have systematically analyzed the global changes in protein levels between the high lipid-producing strain WJ11 and the low lipid-producing strain CBS 277.49 (15%, lipid/cell dry weight) at lipid accumulation phase through comparative proteome analysis. Proteome analysis demonstrated that the branched-chain amino acid and lysine metabolism, glycolytic pathway, and pentose phosphate pathway in WJ11 were up-regulated, while the activities of tricarboxylic acid cycle and branch point enzyme for synthesis of isoprenoids were retarded compared with CBS 277.49. The coordinated regulation at proteome level indicate that more acetyl-CoA and NADPH are provided for fatty acid biosynthesis in WJ11 compared with CBS 277.49.

Draft Genome Sequence of a Clostridium botulinum Isolate from Water Used for Cooling at a Plant Producing Low-Acid Canned Foods.

Science.gov (United States)

Basavanna, Uma; Gonzalez-Escalona, Narjol; Timme, Ruth; Datta, Shomik; Schoen, Brianna; Brown, Eric W; Zink, Donald; Sharma, Shashi K

2013-01-01

Clostridium botulinum is a pathogen of concern for low-acid canned foods. Here we report draft genomes of a neurotoxin-producing C. botulinum strain isolated from water samples used for cooling low-acid canned foods at a canning facility. The genome sequence confirmed that this strain belonged to C. botulinum serotype B1, albeit with major differences, including thousands of unique single nucleotide polymorphisms (SNPs) compared to other genomes of the same serotype.

Draft Genome Sequence of a Clostridium botulinum Isolate from Water Used for Cooling at a Plant Producing Low-Acid Canned Foods

OpenAIRE

Basavanna, Uma; Gonzalez-Escalona, Narjol; Timme, Ruth; Datta, Shomik; Schoen, Brianna; Brown, Eric W.; Zink, Donald; Sharma, Shashi K.

2013-01-01

Clostridium botulinum is a pathogen of concern for low-acid canned foods. Here we report draft genomes of a neurotoxin-producing C.?botulinum strain isolated from water samples used for cooling low-acid canned foods at a canning facility. The genome sequence confirmed that this strain belonged to C.?botulinum serotype B1, albeit with major differences, including thousands of unique single nucleotide polymorphisms (SNPs) compared to other genomes of the same serotype.

Antimicrobial properties of Pseudomonas strains producing the antibiotic mupirocin.

Science.gov (United States)

Matthijs, Sandra; Vander Wauven, Corinne; Cornu, Bertrand; Ye, Lumeng; Cornelis, Pierre; Thomas, Christopher M; Ongena, Marc

2014-10-01

Mupirocin is a polyketide antibiotic with broad antibacterial activity. It was isolated and characterized about 40 years ago from Pseudomonas fluorescens NCIMB 10586. To study the phylogenetic distribution of mupirocin producing strains in the genus Pseudomonas a large collection of Pseudomonas strains of worldwide origin, consisting of 117 Pseudomonas type strains and 461 strains isolated from different biological origins, was screened by PCR for the mmpD gene of the mupirocin gene cluster. Five mmpD(+) strains from different geographic and biological origin were identified. They all produced mupirocin and were strongly antagonistic against Staphylococcus aureus. Phylogenetic analysis showed that mupirocin production is limited to a single species. Inactivation of mupirocin production leads to complete loss of in vitro antagonism against S. aureus, except on certain iron-reduced media where the siderophore pyoverdine is responsible for the in vitro antagonism of a mupirocin-negative mutant. In addition to mupirocin some of the strains produced lipopeptides of the massetolide group. These lipopeptides do not play a role in the observed in vitro antagonism of the mupirocin producing strains against S. aureus. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Competitive Dominance by a Bacteriocin-Producing Vibrio harveyi Strain.

Science.gov (United States)

Hoyt, P R; Sizemore, R K

1982-09-01

Vibrio (Beneckea) harveyi, a bioluminescent marine bacterium, has been shown to produce a bacteriocin-like substance the production of which is mediated by a plasmid. This substance is assumed to be proteinaceous because of its sensitivity to certain proteolytic enzymes. It is stable at low temperatures and can be concentrated by ammonium sulfate precipitation or negative-pressure dialysis. The molecular weight of the bacteriocin was determined to be 2.4 x 10 by molecular exclusion chromatography. Competition experiments indicated that bacteriocin-producing strains predominated over cured variants of the same strain in broth culture experiments. We studied several environmental parameters (pH, salinity, temperature, nutrient concentration) to determine their effects on the competitive advantage bestowed on a bacteriocin-producing strain. Under simulated free-living conditions, no competitive advantage attributable to bacteriocin production was observed. In a simulated enteric habitat, a bacteriocin-producing strain showed dramatic (>90%) inhibition of the sensitive strain within 24 h.

Isolation and functional characterization of the novel Clostridium botulinum neurotoxin A8 subtype.

Science.gov (United States)

Kull, Skadi; Schulz, K Melanie; Weisemann, Jasmin; Kirchner, Sebastian; Schreiber, Tanja; Bollenbach, Alexander; Dabrowski, P Wojtek; Nitsche, Andreas; Kalb, Suzanne R; Dorner, Martin B; Barr, John R; Rummel, Andreas; Dorner, Brigitte G

2015-01-01

Botulism is a severe neurological disease caused by the complex family of botulinum neurotoxins (BoNT). Based on the different serotypes known today, a classification of serotype variants termed subtypes has been proposed according to sequence diversity and immunological properties. However, the relevance of BoNT subtypes is currently not well understood. Here we describe the isolation of a novel Clostridium botulinum strain from a food-borne botulism outbreak near Chemnitz, Germany. Comparison of its botulinum neurotoxin gene sequence with published sequences identified it to be a novel subtype within the BoNT/A serotype designated BoNT/A8. The neurotoxin gene is located within an ha-orfX+ cluster and showed highest homology to BoNT/A1, A2, A5, and A6. Unexpectedly, we found an arginine insertion located in the HC domain of the heavy chain, which is unique compared to all other BoNT/A subtypes known so far. Functional characterization revealed that the binding characteristics to its main neuronal protein receptor SV2C seemed unaffected, whereas binding to membrane-incorporated gangliosides was reduced in comparison to BoNT/A1. Moreover, we found significantly lower enzymatic activity of the natural, full-length neurotoxin and the recombinant light chain of BoNT/A8 compared to BoNT/A1 in different endopeptidase assays. Both reduced ganglioside binding and enzymatic activity may contribute to the considerably lower biological activity of BoNT/A8 as measured in a mouse phrenic nerve hemidiaphragm assay. Despite its reduced activity the novel BoNT/A8 subtype caused severe botulism in a 63-year-old male. To our knowledge, this is the first description and a comprehensive characterization of a novel BoNT/A subtype which combines genetic information on the neurotoxin gene cluster with an in-depth functional analysis using different technical approaches. Our results show that subtyping of BoNT is highly relevant and that understanding of the detailed toxin function might

Organic metabolites produced by Vibrio parahaemolyticus strain ...

African Journals Online (AJOL)

Identification and action of several antibacterial metabolites produced by a fish pathogen Vibrio parahaemolyticus strain An3 from marine ecosystem of Goa has been demonstrated. Antibacterial activity of the crude cell extract of the test bacterium has been evaluated against indicator pathogenic bacterial strains such as ...

Protein Receptor(s) of Botulinum Neurotoxin

Science.gov (United States)

2005-01-01

therapeutic agent, which is a more effective drug in this form than the pure BoNT (12). Again, the molecular basis of the superior therapeutic efficacy of...neurotoxin B, Nat Struct Biol 7, 693-699 36. Hanson, M. A. and Stevens, R. C. (2000) Cocrystal structure of synaptobrevin-II bound to botulinum...designing novel drugs , Biochimie 82 (2000) 943-53. 21. L.A. Smith, Development of recombinant vaccines for botulinum neurotoxin, Toxicon 36 (1998) 539

Botulinum Neurotoxin Injections

Science.gov (United States)

... botulinum neurotoxin as much art as it is science. It is in your best interest to locate the most well-trained and experienced doctor you can find. Before making an appointment to receive botulinum neuro toxin injections, ask the office personnel which doctor ...

Within-mat variability in anatoxin-a and homoanatoxin-a production among benthic Phormidium (cyanobacteria) strains.

Science.gov (United States)

Wood, Susanna A; Smith, Francine M J; Heath, Mark W; Palfroy, Thomas; Gaw, Sally; Young, Roger G; Ryan, Ken G

2012-10-01

Benthic Phormidium mats can contain high concentrations of the neurotoxins anatoxin-a and homoanatoxin-a. However, little is known about the co-occurrence of anatoxin-producing and non-anatoxin-producing strains within mats. There is also no data on variation in anatoxin content among toxic genotypes isolated from the same mat. In this study, 30 Phormidium strains were isolated from 1 cm(2) sections of Phormidium-dominated mats collected from three different sites. Strains were grown to stationary phase and their anatoxin-a, homoanatoxin-a, dihydroanatoxin-a and dihydrohomoanatoxin-a concentrations determined using liquid chromatography-mass spectrometry. Each strain was characterized using morphological and molecular (16S rRNA gene sequences) techniques. Eighteen strains produced anatoxin-a, dihydroanatoxin-a or homoanatoxin-a. Strains isolated from each mat either all produced toxins, or were a mixture of anatoxin and non-anatoxin-producing genotypes. Based on morphology these genotypes could not be separated. The 16S rRNA gene sequence comparisons showed a difference of at least 17 nucleotides among anatoxin and non-anatoxin-producing strains and these formed two separate sub-clades during phylogenetic analysis. The total anatoxin concentration among toxic strains varied from 2.21 to 211.88 mg kg(-1) (freeze dried weight), representing a 100 fold variation in toxin content. These data indicate that both the relative abundance of anatoxin and non-anatoxin-producing genotypes, and variations in anatoxin producing capability, can influence the overall toxin concentration of benthic Phormidium mat samples.

DOMESTIC BUTANOL-PRODUCING STRAINS OF THE Clostridium GENUS

Directory of Open Access Journals (Sweden)

O. O. Tigunova

2017-02-01

Full Text Available The aim of the work was to summarize the results of own research concerning obtaining butanol producing strains of Clostridium genus, to identify them by physiological, morphological and genetic methods. Further study of characteristics and biological features of the strains, and various approaches in biotechnological process of butanol production are discussed. The work includes methods to increase butanol accumulation by producer strains. Perspectives of using chemical mutagenesis in Clostridia as a method of increasing butanol production are considered. The feasibility of using non-food raw material as a substrate for fermentation is discussed. Different methods of pretreatment and their impact on the accumulation of butanol in the liquid medium are compared. Butanol accumulation is shown to increase significantly if the synthesis precursors are added as components of enzymatic medium, and the “reverse bard” is used to reduce waste production without affecting the level of butanol synthesis. The problem of conservation of producing strains is given, and protective medium for microorganisms during the freeze-drying is defined.

Fetal exposure to environmental neurotoxins in Taiwan.

Science.gov (United States)

Jiang, Chuen-Bin; Hsi, Hsing-Cheng; Fan, Chun-Hua; Chien, Ling-Chu

2014-01-01

Mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) are recognized neurotoxins in children that particularly affect neurodevelopment and intellectual performance. Based on the hypothesis that the fetal basis of adult disease is fetal toxic exposure that results in adverse outcomes in adulthood, we explored the concentrations of key neurotoxins (i.e., Hg, Pb, Cd, and As) in meconium to identify the risk factors associated with these concentrations. From January 2007 to December 2009, 545 mother-infant pairs were recruited. The geometric mean concentrations of Pb and As in the meconium of babies of foreign-born mothers (22.9 and 38.1 µg/kg dry weight, respectively) were significantly greater than those of babies of Taiwan-born mothers (17.5 and 33.0 µg/kg dry weight, respectively). Maternal age (≥30 y), maternal education, use of traditional Chinese herbs during pregnancy, and fish cutlet consumption (≥3 meals/wk) were risk factors associated with concentrations of key prenatal neurotoxins. The Taiwan government should focus more attention on providing intervention programs for immigrant mothers to help protect the health of unborn babies. Further investigation on how multiple neurotoxins influence prenatal neurodevelopment is warranted.

Fetal exposure to environmental neurotoxins in Taiwan.

Directory of Open Access Journals (Sweden)

Chuen-Bin Jiang

Full Text Available Mercury (Hg, lead (Pb, cadmium (Cd, and arsenic (As are recognized neurotoxins in children that particularly affect neurodevelopment and intellectual performance. Based on the hypothesis that the fetal basis of adult disease is fetal toxic exposure that results in adverse outcomes in adulthood, we explored the concentrations of key neurotoxins (i.e., Hg, Pb, Cd, and As in meconium to identify the risk factors associated with these concentrations. From January 2007 to December 2009, 545 mother-infant pairs were recruited. The geometric mean concentrations of Pb and As in the meconium of babies of foreign-born mothers (22.9 and 38.1 µg/kg dry weight, respectively were significantly greater than those of babies of Taiwan-born mothers (17.5 and 33.0 µg/kg dry weight, respectively. Maternal age (≥30 y, maternal education, use of traditional Chinese herbs during pregnancy, and fish cutlet consumption (≥3 meals/wk were risk factors associated with concentrations of key prenatal neurotoxins. The Taiwan government should focus more attention on providing intervention programs for immigrant mothers to help protect the health of unborn babies. Further investigation on how multiple neurotoxins influence prenatal neurodevelopment is warranted.

Comparison of oral toxicological properties of botulinum neurotoxin

Science.gov (United States)

Botulinum neurotoxins (BoNTs) are among the most potent biological toxins for humans. Of the seven known serotypes (A-G) of BoNT, serotypes A, B and E cause most of the foodborne intoxications in humans. BoNTs in nature are associated with non-toxic accessory proteins known as neurotoxin-associated ...

Innovative mode of action based in vitro assays for detection of marine neurotoxins

NARCIS (Netherlands)

Nicolas, J.A.Y.

2015-01-01

Innovative mode of action based in vitro assays for detection of marine neurotoxins

J. Nicolas, P.J.M. Hendriksen, T.F.H. Bovee, I.M.C.M. Rietjens

Marine biotoxins are naturally occurring compounds produced by particular phytoplankton species. These toxins often accumulate in

Isolation and functional characterization of the novel Clostridium botulinum neurotoxin A8 subtype.

Directory of Open Access Journals (Sweden)

Skadi Kull

Full Text Available Botulism is a severe neurological disease caused by the complex family of botulinum neurotoxins (BoNT. Based on the different serotypes known today, a classification of serotype variants termed subtypes has been proposed according to sequence diversity and immunological properties. However, the relevance of BoNT subtypes is currently not well understood. Here we describe the isolation of a novel Clostridium botulinum strain from a food-borne botulism outbreak near Chemnitz, Germany. Comparison of its botulinum neurotoxin gene sequence with published sequences identified it to be a novel subtype within the BoNT/A serotype designated BoNT/A8. The neurotoxin gene is located within an ha-orfX+ cluster and showed highest homology to BoNT/A1, A2, A5, and A6. Unexpectedly, we found an arginine insertion located in the HC domain of the heavy chain, which is unique compared to all other BoNT/A subtypes known so far. Functional characterization revealed that the binding characteristics to its main neuronal protein receptor SV2C seemed unaffected, whereas binding to membrane-incorporated gangliosides was reduced in comparison to BoNT/A1. Moreover, we found significantly lower enzymatic activity of the natural, full-length neurotoxin and the recombinant light chain of BoNT/A8 compared to BoNT/A1 in different endopeptidase assays. Both reduced ganglioside binding and enzymatic activity may contribute to the considerably lower biological activity of BoNT/A8 as measured in a mouse phrenic nerve hemidiaphragm assay. Despite its reduced activity the novel BoNT/A8 subtype caused severe botulism in a 63-year-old male. To our knowledge, this is the first description and a comprehensive characterization of a novel BoNT/A subtype which combines genetic information on the neurotoxin gene cluster with an in-depth functional analysis using different technical approaches. Our results show that subtyping of BoNT is highly relevant and that understanding of the detailed

Assembly and function of the botulinum neurotoxin progenitor complex.

Science.gov (United States)

Gu, Shenyan; Jin, Rongsheng

2013-01-01

Botulinum neurotoxins (BoNTs) are among the most poisonous substances known to man, but paradoxically, BoNT-containing medicines and cosmetics have been used with great success in the clinic. Accidental BoNT poisoning mainly occurs through oral ingestion of food contaminated with Clostridium botulinum. BoNTs are naturally produced in the form of progenitor toxin complexes (PTCs), which are high molecular weight (up to ~900 kDa) multiprotein complexes composed of BoNT and several non-toxic neurotoxin-associated proteins (NAPs). NAPs protect the inherently fragile BoNTs against the hostile environment of the gastrointestinal (GI) tract and help BoNTs pass through the intestinal epithelial barrier before they are released into the general circulation. These events are essential for ingested BoNTs to gain access to motoneurons, where they inhibit neurotransmitter release and cause muscle paralysis. In this review, we discuss the structural basis for assembly of NAPs and BoNT into the PTC that protects BoNT and facilitate its delivery into the bloodstream.

NEW PRODUCER STRAINS OF BIOBUTANOL. І. ISOLATION AND IDENTIFICATION

Directory of Open Access Journals (Sweden)

O. A. Tigunova

2013-02-01

Full Text Available Getting new, more productive strains of microorganisms that produce butanol is a topical problem. Studing of morphological and physiological characteristics of the isolated strains, improvement of their cultivation conditions, optimization of biobutanol synthesis gives the possibility to organize a cost-effective butanol production technology. The aim of this work was searching new butanol and butyric acid producer strains, their identification and studying the main steps of the selective strains biosynthesis. The objects of this study were microorganisms that had allocated from soils and sludges samples of Kiev’s lakes. Obtained cultures have been screened. Three strains were obtained as promising and identified as C. acetobutylicum, C. tyrobutylicum, C. butylicum. Selective medium have been developed and modified for the microorganisms. Producer’s features were investigated in order to maximize the accumulation of target metabolites.

Fetal Exposure to Environmental Neurotoxins in Taiwan

OpenAIRE

Jiang, Chuen-Bin; Hsi, Hsing-Cheng; Fan, Chun-Hua; Chien, Ling-Chu

2014-01-01

Mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) are recognized neurotoxins in children that particularly affect neurodevelopment and intellectual performance. Based on the hypothesis that the fetal basis of adult disease is fetal toxic exposure that results in adverse outcomes in adulthood, we explored the concentrations of key neurotoxins (i.e., Hg, Pb, Cd, and As) in meconium to identify the risk factors associated with these concentrations. From January 2007 to December 2009, 545 m...

LYOPHILIZATION EFFECT ON PRODUCTIVITY OF BUTANOL-PRODUCING STRAINS

Directory of Open Access Journals (Sweden)

O. O. Tigunova

2016-10-01

Full Text Available Investigation of lyophilization effect on the productivity of butanol-producing strains was the aim of our research. For this purpose we used butanol-producing strains; technical glycerol; biomass of switchgrass Panicum virgatum L. Lyophilization was performed using a lyophilization-drying. The effect of the protective medium on residual moisture of freezedrying cultures suspensions depending on the concentration of glucose and sucrose was studed. It was shown that the lowest residual moisture was attained by using glucose and sucrose in amount of 10% and if the samples of freeze-drying bacteria had been saved for one month at 4 οC the productivity did not decrease. As temperature preservation was increased the productivity of the cultures was gradually decreased and it was greatly reduced at 30 οC. So the protective medium composition was optimized for lyophilization of butanol-producing strains as follows: sucrose 10.0%; gelatin 10.0%; agar 0.02%. It was shown that the preservation of samples of freeze-drying bacteria for six months at a temperature of 4 οC did not affect the productivity of strains. It was found that cultures could use glycerol as a carbon source for butanol accumulation before lyophilization.

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones.

Science.gov (United States)

Moran, Yehu; Genikhovich, Grigory; Gordon, Dalia; Wienkoop, Stefanie; Zenkert, Claudia; Ozbek, Suat; Technau, Ulrich; Gurevitz, Michael

2012-04-07

Jellyfish, hydras, corals and sea anemones (phylum Cnidaria) are known for their venomous stinging cells, nematocytes, used for prey and defence. Here we show, however, that the potent Type I neurotoxin of the sea anemone Nematostella vectensis, Nv1, is confined to ectodermal gland cells rather than nematocytes. We demonstrate massive Nv1 secretion upon encounter with a crustacean prey. Concomitant discharge of nematocysts probably pierces the prey, expediting toxin penetration. Toxin efficiency in sea water is further demonstrated by the rapid paralysis of fish or crustacean larvae upon application of recombinant Nv1 into their medium. Analysis of other anemone species reveals that in Anthopleura elegantissima, Type I neurotoxins also appear in gland cells, whereas in the common species Anemonia viridis, Type I toxins are localized to both nematocytes and ectodermal gland cells. The nematocyte-based and gland cell-based envenomation mechanisms may reflect substantial differences in the ecology and feeding habits of sea anemone species. Overall, the immunolocalization of neurotoxins to gland cells changes the common view in the literature that sea anemone neurotoxins are produced and delivered only by stinging nematocytes, and raises the possibility that this toxin-secretion mechanism is an ancestral evolutionary state of the venom delivery machinery in sea anemones.

Phylogeny of the ammonia-producing ruminal bacteria Peptostreptococcus anaerobius, Clostridium sticklandii, and Clostridium aminophilum sp. nov

Science.gov (United States)

Paster, B. J.; Russell, J. B.; Yang, C. M.; Chow, J. M.; Woese, C. R.; Tanner, R.

1993-01-01

In previous studies, gram-positive bacteria which grew rapidly with peptides or an amino acid as the sole energy source were isolated from bovine rumina. Three isolates, strains C, FT (T = type strain), and SR, were considered to be ecologically important since they produced up to 20-fold more ammonia than other ammonia-producing ruminal bacteria. On the basis of phenotypic criteria, the taxonomic position of these new isolates was uncertain. In this study, the 16S rRNA sequences of these isolates and related bacteria were determined to establish the phylogenetic positions of the organisms. The sequences of strains C, FT, and SR and reference strains of Peptostreptococcus anaerobius, Clostridium sticklandii, Clostridium coccoides, Clostridium aminovalericum, Acetomaculum ruminis, Clostridium leptum, Clostridium lituseburense, Clostridium acidiurici, and Clostridium barkeri were determined by using a modified Sanger dideoxy chain termination method. Strain C, a large coccus purported to belong to the genus Peptostreptococcus, was closely related to P. anaerobius, with a level of sequence similarity of 99.6%. Strain SR, a heat-resistant, short, rod-shaped organism, was closely related to C. sticklandii, with a level of sequence similarity of 99.9%. However, strain FT, a heat-resistant, pleomorphic, rod-shaped organism, was only distantly related to some clostridial species and P. anaerobius. On the basis of the sequence data, it was clear that strain FT warranted designation as a separate species. The closest known relative of strain FT was C. coccoides (level of similarity, only 90.6%). Additional strains that are phenotypically similar to strain FT were isolated in this study.(ABSTRACT TRUNCATED AT 250 WORDS).

Clostridial necrotic enteritis in chicken associated with growth rate depression

Directory of Open Access Journals (Sweden)

Adin Priadi

2008-03-01

Full Text Available Clostridium perfringens (C. perfringens is a normal inhabitant of the intestinal tract of chickens as well as a potential pathogen causing necrotic enteritis. C. perfringens only causes necrotic enteritis when it transforms from non-toxin producing type to toxin producing type. The alpha toxin, (phospholipase C is believed to be a key to the occurrence of Clostridial necrotic enteritis (CNE. The best known predisposing factor is mucosal damage, caused by coccidiosis that damages the intestinal lining, making the gut susceptible to infections including C. perfringens. The purpose of this study was to observe the chicken performance in experimental CNE and field cases of CNE. Diagnosis of CNE were made by latex agglutination test, isolation and identification of the agent. Pathological and histopathological changes were also observed. Experimentally, NE could be reproduced when Eimeria sp and C. perfringens spores are inoculated in chicken. Signs of an NE are wet litter and diarrhea, and an increase in mortality is not often obvious. The depression of growth rate and feed efficiency of chicken become noticeable by week 5 because of damage to the intestine and the subsequent reduction in digestion and absorption of food. Subclinical form of CNE was also frequently found in the field, leading to significant decreases in performance. Chicken gut samples examinations revealed that subclinical form of CNE causes damage to the intestinal mucosa caused by C. perfringens leads to decreased digestion and absorption, increased feed conversion ratio and reduced weight gain. Dual infection with C. perfringens and Eimeria sp. was frequently found in field. The results of these studies provide evidence for C. perfringens as a causative bacteria for growth depression.

Isolation and characterization of lipase-producing Bacillus strains ...

African Journals Online (AJOL)

Bacillus strains (B1 - B5) producing extra cellular lipase were isolated from the soil sample of coconut oil industry. The strains were identified by morphological and biochemical characters. Growth of the organisms and lipase production were measured with varying pH (4 - 9) temperature (27, 37 and 47ºC) and various ...

Mechanisms of Resistance to Neurotoxins

National Research Council Canada - National Science Library

Schubert, David

2002-01-01

The toxicity of chemically reactive oxygen species (ROS) is thought to make a significant contribution to the death of nerve cells caused by many neurotoxins as well as in stroke and Parkinson's disease...

Effect of nitrogen on cellular production and release of the neurotoxin anatoxin-a in a nitrogen-fixing cyanobacterium

Directory of Open Access Journals (Sweden)

Alexis eGagnon

2012-06-01

Full Text Available Anatoxin-a (ANTX is a neurotoxin produced by several freshwater cyanobacteria and implicated in lethal poisonings of domesticated animals and wildlife. The factors leading to its production in nature and in culture are not well understood. Resource availability may influence its cellular production as suggested by the carbon-nutrient hypothesis, which links the amount of secondary metabolites produced by plants or microbes to the relative abundance of nutrients. We tested the effects of nitrogen supply on ANTX production and release in a toxic strain of the cyanobacterium Aphanizomenon issatschenkoi (Nostocales. We hypothesized that nitrogen deficiency might constrain the production of ANTX. However, the total concentration and more significantly the cellular content of anatoxin-a peaked (max. 146 µg/L and 1683 µg•g-1 dry weight at intermediate levels of nitrogen supply when N-deficiency was evident based on phycocyanin to chlorophyll a and carbon to nitrogen ratios. The results suggest that the cellular production of anatoxin-a may be stimulated by moderate nutrient stress as described recently for another cyanotoxin (microcystin.

A monoclonal antibody based capture ELISA for botulinum neurotoxin serotype B: toxin detection in food

Science.gov (United States)

Botulism is a serious foodborne neuroparalyic disease caused by botulinum neurotoxin (BoNT) produced by the anaerobic bacterium Clostridium botulinum. Seven toxin serotypes (A-H) have been described. The majority of human cases of botulism are caused by serotypes A and B followed by E and F. We repo...

Divergence in wine characteristics produced by wild and domesticated strains of Saccharomyces cerevisiae

Science.gov (United States)

Hyma, Katie E; Saerens, Sofie M; Verstrepen, Kevin J; Fay, Justin C

2011-01-01

The budding yeast Saccharomyces cerevisiae is the primary species used by wine makers to convert sugar into alcohol during wine fermentation. Saccharomyces cerevisiae is found in vineyards, but is also found in association with oak trees and other natural sources. Although wild strains of S. cerevisiae as well as other Saccharomyces species are also capable of wine fermentation, a genetically distinct group of S. cerevisiae strains is primarily used to produce wine, consistent with the idea that wine making strains have been domesticated for wine production. In this study, we demonstrate that humans can distinguish between wines produced using wine strains and wild strains of S. cerevisiae as well as its sibling species, Saccharomyces paradoxus. Wine strains produced wine with fruity and floral characteristics, whereas wild strains produced wine with earthy and sulfurous characteristics. The differences that we observe between wine and wild strains provides further evidence that wine strains have evolved phenotypes that are distinct from their wild ancestors and relevant to their use in wine production. PMID:22093681

Volatile compounds of Aspergillus strains with different abilities to produce ochratoxin A.

Science.gov (United States)

Jeleń, Henryk H; Grabarkiewicz-Szczesna, Jadwiga

2005-03-09

Volatile compounds emitted by Aspergillus strains having different abilities to produce ochratoxin A were investigated. Thirteen strains of Aspergillus ochraceus, three belonging to the A. ochraceus group, and eight other species of Aspergillus were examined for their abilities to produce volatile compounds and ochratoxin A on a wheat grain medium. The profiles of volatile compounds, analyzed using SPME, in all A. ochraceus strains, regardless of their toxeginicity, were similar and comprised mainly of 1-octen-3-ol, 3-octanone, 3-octanol, 3-methyl-1-butanol, 1-octene, and limonene. The prevailing compound was always 1-octen-3-ol. Mellein, which forms part of the ochratoxin A molecule, was found in both toxigenic and nontoxigenic strains. Volatile compounds produced by other Aspergillus strains were similar to those of A. ochraceus. Incubation temperatures (20, 24, and 27 degrees C) and water content in the medium (20, 30, and 40%) influenced both volatile compounds formation and ochratoxin A biosynthesis efficiency, although conditions providing the maximum amount of volatiles were different from those providing the maximum amount of ochratoxin A. The pattern of volatiles produced by toxigenic A. ochraceus strains does not facilitate their differentiation from nontoxigenic strains.

Probiotic Properties of Exopolysaccharide-Producing Lactobacillus Strains Isolated from Tempoyak

Directory of Open Access Journals (Sweden)

Eilaf Suliman Khalil

2018-02-01

Full Text Available Tempoyak is a functional Malaysian food (an acid-fermented condiment which is produced from the pulp of the durian (Durio zibethinus fruit. The current study aimed to isolate and identify potential exopolysaccharide (EPS-producing Lactobacillus strains from tempoyak for potential use as probiotics. Seven isolates (DUR2, DUR4, DUR5, DUR8, DUR12, DUR18, and DUR20 out of 44 were able to produce EPS, and exhibited resistance to acid and bile salt compared to the reference strains Lactobacillus rhmnosus (ATCC53103 and L. plantarum (ATCC8014. The seven isolated strains belonged to five different species—L. plantarum, L. fermentum, L. crispatus, L. reuteri, and L. pentosus—which were identified using API 50 CHL and 16S rRNA gene sequences (Polymerase chain reaction, PCR – based. The seven strains displayed different ability to produce EPS (100–850 mg/L. Isolates exhibited a high survivability to acid (pH 3.0, bile salts (0.3%, and gastrointestinal tract model (<70%. Results showed that the auto-aggregation and cell surface hydrophobicity ranged from 39.98% to 60.09% and 50.80% to 80.53%, respectively, whereas, the highest co-aggregation value (66.44% was observed by L. fermentum (DUR8 with Pseudomonas aeruginosa. The isolates showed good inhibitory activity against tested pathogens, high antioxidant activity (32.29% to 73.36%, and good ability to reduce cholesterol (22.55% to 75.15%. Thus, the seven tested strains have value as probiotics.

Molecular Analysis of Neurotoxin-Induced Apoptosis

National Research Council Canada - National Science Library

D'Mello, Santosh R

2006-01-01

Apoptosis is a cell-suicide process that is required for the normal development of the nervous system, but that can be aberrantly activated in neurodegenerative diseases and following exposure to neurotoxins...

Therapeutic applications of botulinum neurotoxins in head and neck disorders

Directory of Open Access Journals (Sweden)

Ahmad Alshadwi

2015-01-01

Conclusion: Botulinum neurotoxin therapy provides viable alternatives to traditional treatment modalities for some conditions affecting the head and neck region that have neurological components. This therapy can overcome some of the morbidities associated with conventional therapy. More research is needed to determine the ideal doses of botulinum neurotoxin to treat different diseases affecting the head and neck regions.

Capturing one of the human gut microbiome’s most wanted: reconstructing the genome of a novel butyrate-producing, clostridial scavenger from metagenomic sequence data

Directory of Open Access Journals (Sweden)

Patricio eJeraldo

2016-05-01

Full Text Available The role of the microbiome in health and disease is attracting great attention, yet we still know little about some of the most prevalent microorganisms inside our bodies. Several years ago, Human Microbiome Project (HMP researchers generated a list of most wanted taxa: bacteria both prevalent among healthy volunteers and distantly related to any sequenced organisms. Unfortunately, the challenge of assembling high-quality genomes from a tangle of metagenomic reads has slowed progress in learning about these uncultured bacteria. Here, we describe how recent advances in sequencing and analysis allowed us to assemble most wanted genomes from metagenomic data collected from four stool samples. Using a combination of both de novo and guided assembly methods, we assembled and binned over 100 genomes from an initial data set of over 1,300 Gbp. One of these genome bins, which met HMP’s criteria for a most wanted taxa, contained three essentially complete genomes belonging to a previously uncultivated species. This species is most closely related to Eubacterium desmolans and the clostridial cluster IV/Clostridium leptum subgroup species Butyricicoccus pullicaecorum (71–76% average nucleotide identity. Gene function analysis indicates that the species is an obligate anaerobe, forms spores, and produces the anti-inflammatory short-chain fatty acids acetate and butyrate. It also appears to take up metabolically costly molecules such as cobalamin, methionine, and branch-chained amino acids from the environment, and to lack virulence genes. Thus, the evidence is consistent with a secondary degrader that occupies a host-dependent, nutrient-scavenging niche within the gut; its ability to produce butyrate, which is thought to play an anti-inflammatory role, makes it intriguing for the study of diseases such as colon cancer and inflammatory bowel disease. In conclusion, we have assembled essentially complete genomes from stool metagenomic data, yielding

Mechanisms of Resistance to Neurotoxins (Addendum)

National Research Council Canada - National Science Library

Schubert, David

2003-01-01

The toxicity of chemically reactive oxygen species (ROS) is thought to make a significant contribution to the death of nerve cells caused by many neurotoxins as well as in stroke and Parkinson's disease...

New rifamycins produced by a recombinant strain of Nocardia mediterranei.

Science.gov (United States)

Schupp, T; Traxler, P; Auden, J A

1981-08-01

A recombinant strain of Nocardia mediterranei was found to produce a number of new rifamycins which are structurally related to rifamycin S, rifamycin W and rifamycin G. This strain was derived from two Nocardia mediterranei mutants by intraspecific recombination.

[Isolation, identification and characterization of acid-producing strains from psychrotolerant biogas fermentation].

Science.gov (United States)

Wan, Yongqing; Zhang, Wei; Mandlaa; Tian, Ruihua; Wang, Ruigang; Duan, Kaihong

2015-11-04

The aim of this study was to screen acid-producing strains from the broth of psychrotolerant biogas fermentation and evaluate the acid-producing character of them. Acid-producing strains were isolated by a medium with methyl red at 4 degrees C in Petri dishes and identified by morphology observation and 16S rRNA sequencing. Moreover, the ability of hydrolysis of starch, fermentation of carbohydrates, liquefaction of gelatin and production of catalase were studied. Two acid-producing strains (FJ-8 and FJ-15) were isolated. The result of the 16S rRNA phylogenetic tree shows that FJ-8 and FJ-15 belong to Pseudomonas sp. and Shewanella sp., respectively. Both FJ-8 and FJ-15 could hydrolyze starch, liquidize gelatin and produce catalase. The optimum temperature for acid-producing of FJ-8 and FJ-15 is 15 degrees C and 20 degrees C, respectively. After 10 days cultivation at 4 degrees C, the concentration of acetic acid was 792 mg/L and 966 mg/L of FJ-8 and FJ-15, respectively. The selected strains, FJ-8 and FJ-15, have the potential to produce acids at low temperature.

Probiotic microorganisms inhibit epithelial cell internalization of botulinum neurotoxin serotype A

Science.gov (United States)

Botulinum neurotoxins (BoNTs) are some of the most poisonous natural toxins known to man and are threats to public health and safety. Previous work from our laboratory showed that BoNT serotype A (BoNT/A) complex (holotoxin with neurotoxin-associated proteins) bind and transit through the intestinal...

Technological and safety properties of newly isolated GABA-producing Lactobacillus futsaii strains.

Science.gov (United States)

Sanchart, C; Rattanaporn, O; Haltrich, D; Phukpattaranont, P; Maneerat, S

2016-09-01

To evaluate the technological and safety properties of Lactobacillus futsaii CS3 and CS5 isolated from Thai fermented shrimp products (Kung-Som) in order to develop a valuable gamma-aminobutyric acid (GABA)-producing starter culture. Both strains showed a high GABA-producing ability (>8 mg ml(-1) ) in MRS broth containing 20 mg ml(-1) monosodium glutamate (MSG) for 120 h. They also exhibited inhibitory activity against foodborne pathogens and spoilage bacteria. Cell surface hydrophobicity and proteolytic activity were observed in both strains. Strain CS3 survived better under simulated gastrointestinal tract conditions with only 1·5 log-units cell decrease over 8 h. Both strains showed the ability to deconjugate taurocholate and taurodeoxycholate acid. Neither virulence genes nor biogenic amine production was detected. Strain CS3 exhibited susceptibility to all tested antibiotics with the exception of vancomycin, while strain CS5 showed resistance to vancomycin, ampicillin and chloramphenicol. Based on the results obtained, Lact. futsaii CS3 is very promising as a GABA-producing and potentially probiotic starter culture strain for applications in functional fermented foods. This study focuses on the technological and safety characteristics of Lact. futsaii CS3 and CS5 including their high GABA-producing capacity for the first time. This provides a way of replacing chemical GABA by natural GABA using a GABA-producing starter culture candidate, at the same time offering the consumer new attractive food products. © 2016 The Society for Applied Microbiology.

Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

NARCIS (Netherlands)

Geel-Schutten, G.H. van; Flesch, F.; Brink, B. ten; Smith, M.R.; Dijkhuizen, L.

1998-01-01

A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identified; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent

Therapeutic tests on methylcholanthrene-induced fibrosarcoma and transplanted fibrosarcoma of the mouse - clostridial oncolysis and its enhancement by high-frequency hyperthermia and X-rays

International Nuclear Information System (INIS)

Pirlet, T.

1982-01-01

Tests aimed at a conditioning of tumours by means of x-ray irradiation and high-frequency hyperthermia. Methyl cholanthrene-induced fibrosarcoma (IMCM) and its transplant version (T-IMCM) produced at the neck of NMRI-mice at a critical localization immediately next to vital organs, served as a test system since it is almost resistant to simple oncolysis. Individual therapy components were compared for their mutual enhancement of efficacy in 16 test groups, and the triple combination (Cl + X-ray + HFH) was tested in relapse application as well. A 2000-R-x-ray irradiation was followed by almost simultaneous 4 min HF heating and i.v. spore administration at 12 h intervals. Assessment criteria were tumour growth, survival rates and times, absence of recidivity and healing, analysis of post-mortem findings and dimension or duration of lyses. In addition, the two tumour types of induction and transplant tumour were compared. The typical course of clostridial oncolysis can be confirmed in principle. Results show that it is possible by means of additional physical methods as were applied, to increase the systemically apathogenic and selective therapy principle of rather negligible oncolysis to over 80% (IMCM) or 97% (T-IMCM). Concerning the MCA fibrosarcoma which is very resistant to clostridial oncolysis in this mouse-tumour model, marked prolongations of survival or healing are possible even in extremely critical localization. In principle, this provides the preconditions for including oncolysis in clinical studies in human medicine. (orig./MG) [de

NEW STRAINS PRODUCER OF BIOBUTANOL. ІІ. RENEWABLE LIGNOCELLULOSE FERMENTATION

Directory of Open Access Journals (Sweden)

Tigunova O. O.

2014-08-01

Full Text Available The purpose of our work was to study generic and specific affinity of domestic strainsproducers, comparative productivity butanol strains-producers screening, fermentation of sugars being a part of renewable lignocelluloses raw materials and to determine the conditions for the butanol yield increasing. The objects of research were strains Clostridium acetobutylicum ІМВ В-7407 (IFBG C6H, IFBG C4B and IFBG C7P from «Collection microorganism’s stains and plants line for food and agriculture biotechnology» of Institute of Food Biotechnology and Genomics of the National Academy of Sciences of Ukraine. It was determined that domestic butanol-producing strains were relatively more productive and might be promising for improvement technology of butanol production.

[Morphological characteristics and physiological properties of aflatoxin B1 producing and non-producing Aspergillus flavus strains].

Science.gov (United States)

Kogbo, W; Lemarinier, S; Boutibonnes, P

1985-09-01

Comparison between about 80 strains of Aspergillus flavus, belonging to the series flavus and oryzae, obtained from international collections but also isolated from French or African substrates revealed the following observations: 1. Cultural and morphological characteristics of toxicogenic and atoxicogenic strains of A. flavus are similar. However, the former produce a diffusible yellow pigment in 83% of isolates. 2. The two groups of conidiospores have the same resistance to UV irradiation (254 nm, 5 and 10 min). All the strains are equally sensitive to 4 antifungal antibiotics: nystatine, ketoconazole, clotrimazole and amphotericine. 3. A difference was seen in the capacity to produce enzymes as alpha-galactosidase, beta-galactosidase and beta-glucosidase, implicated in the glucid metabolism. The specific hydrolytic activity has been confirmed by the characterization of a large amount of beta-galactosidase and by a diauxic growth on glucose medium supplemented by lactose. Possible relationship between these characters and aflatoxin B1 production by A. flavus strains is discussed.

Botulinum neurotoxin B recognizes its protein receptor with high affinity and specificity.

Science.gov (United States)

Jin, Rongsheng; Rummel, Andreas; Binz, Thomas; Brunger, Axel T

2006-12-21

Botulinum neurotoxins (BoNTs) are produced by Clostridium botulinum and cause the neuroparalytic syndrome of botulism. With a lethal dose of 1 ng kg(-1), they pose a biological hazard to humans and a serious potential bioweapon threat. BoNTs bind with high specificity at neuromuscular junctions and they impair exocytosis of synaptic vesicles containing acetylcholine through specific proteolysis of SNAREs (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors), which constitute part of the synaptic vesicle fusion machinery. The molecular details of the toxin-cell recognition have been elusive. Here we report the structure of a BoNT in complex with its protein receptor: the receptor-binding domain of botulinum neurotoxin serotype B (BoNT/B) bound to the luminal domain of synaptotagmin II, determined at 2.15 A resolution. On binding, a helix is induced in the luminal domain which binds to a saddle-shaped crevice on a distal tip of BoNT/B. This crevice is adjacent to the non-overlapping ganglioside-binding site of BoNT/B. Synaptotagmin II interacts with BoNT/B with nanomolar affinity, at both neutral and acidic endosomal pH. Biochemical and neuronal ex vivo studies of structure-based mutations indicate high specificity and affinity of the interaction, and high selectivity of BoNT/B among synaptotagmin I and II isoforms. Synergistic binding of both synaptotagmin and ganglioside imposes geometric restrictions on the initiation of BoNT/B translocation after endocytosis. Our results provide the basis for the rational development of preventive vaccines or inhibitors against these neurotoxins.

Single and combined effects of microcystin- and saxitoxin-producing cyanobacteria on the fitness and antioxidant defenses of cladocerans.

Science.gov (United States)

da S Ferrão-Filho, Aloysio; de Abreu S Silva, Daniel; de Oliveira, Taissa A; de Magalhães, Valéria Freitas; Pflugmacher, Stephan; da Silva, Eduardo Mendes

2017-10-01

Cyanobacteria produce different toxic compounds that affect animal life, among them hepatotoxins and neurotoxins. Because cyanobacteria are able to produce a variety of toxic compounds at the same time, organisms may be, generally, subjected to their combined action. In the present study, we demonstrate the single and combined effects on cladocerans of cyanobacteria that produce microcystins (hepatotoxins) and saxitoxins (neurotoxins). Animals were exposed (either singly or combined) to 2 strains of cyanobacteria isolated from the same environment (Funil Reservoir, Rio de Janeiro, Brazil). The effects on clearance rate, mobility, survivorship, fecundity, population increase rate (r), and the antioxidant enzymes glutathione-S-transferase (GST) and catalase (CAT) were measured. Cladoceran species showed a variety of responses to cyanobacterial exposures, going from no effect to impairment of swimming movement, lower survivorship, fecundity, and general fitness (r). Animals ingested cyanobacteria in all treatments, although at lower rates than good food (green algae). Antioxidant defense responses were in accordance with fitness responses, suggesting that oxidative stress may be related to such effects. The present study emphasizes the need for testing combined actions of different classes of toxins, because this is often, and most likely, the scenario in a more eutrophic world with global climatic changes. Environ Toxicol Chem 2017;36:2689-2697. © 2017 SETAC. © 2017 SETAC.

A rapid colorimetric screening method for vanillic acid and vanillin-producing bacterial strains.

Science.gov (United States)

Zamzuri, N A; Abd-Aziz, S; Rahim, R A; Phang, L Y; Alitheen, N B; Maeda, T

2014-04-01

To isolate a bacterial strain capable of biotransforming ferulic acid, a major component of lignin, into vanillin and vanillic acid by a rapid colorimetric screening method. For the production of vanillin, a natural aroma compound, we attempted to isolate a potential strain using a simple screening method based on pH change resulting from the degradation of ferulic acid. The strain Pseudomonas sp. AZ10 UPM exhibited a significant result because of colour changes observed on the assay plate on day 1 with a high intensity of yellow colour. The biotransformation of ferulic acid into vanillic acid by the AZ10 strain provided the yield (Yp/s ) and productivity (Pr ) of 1·08 mg mg(-1) and 53·1 mg L(-1) h(-1) , respectively. In fact, new investigations regarding lignin degradation revealed that the strain was not able to produce vanillin and vanillic acid directly from lignin; however, partially digested lignin by mixed enzymatic treatment allowed the strain to produce 30·7 mg l(-1) and 1·94 mg l(-1) of vanillic acid and biovanillin, respectively. (i) The rapid colorimetric screening method allowed the isolation of a biovanillin producer using ferulic acid as the sole carbon source. (ii) Enzymatic treatment partially digested lignin, which could then be utilized by the strain to produce biovanillin and vanillic acid. To the best of our knowledge, this is the first study reporting the use of a rapid colorimetric screening method for bacterial strains producing vanillin and vanillic acid from ferulic acid. © 2013 The Society for Applied Microbiology.

Flagellin Diversity in Clostridium botulinum Groups I and II: a New Strategy for Strain Identification▿

Science.gov (United States)

Paul, Catherine J.; Twine, Susan M.; Tam, Kevin J.; Mullen, James A.; Kelly, John F.; Austin, John W.; Logan, Susan M.

2007-01-01

Strains of Clostridium botulinum are traditionally identified by botulinum neurotoxin type; however, identification of an additional target for typing would improve differentiation. Isolation of flagellar filaments and analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that C. botulinum produced multiple flagellin proteins. Nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) analysis of in-gel tryptic digests identified peptides in all flagellin bands that matched two homologous tandem flagellin genes identified in the C. botulinum Hall A genome. Designated flaA1 and flaA2, these open reading frames encode the major structural flagellins of C. botulinum. Colony PCR and sequencing of flaA1/A2 variable regions classified 80 environmental and clinical strains into group I or group II and clustered isolates into 12 flagellar types. Flagellar type was distinct from neurotoxin type, and epidemiologically related isolates clustered together. Sequencing a larger PCR product, obtained during amplification of flaA1/A2 from type E strain Bennett identified a second flagellin gene, flaB. LC-MS analysis confirmed that flaB encoded a large type E-specific flagellin protein, and the predicted molecular mass for FlaB matched that observed by SDS-PAGE. In contrast, the molecular mass of FlaA was 2 to 12 kDa larger than the mass predicted by the flaA1/A2 sequence of a given strain, suggesting that FlaA is posttranslationally modified. While identification of FlaB, and the observation by SDS-PAGE of different masses of the FlaA proteins, showed the flagellin proteins of C. botulinum to be diverse, the presence of the flaA1/A2 gene in all strains examined facilitates single locus sequence typing of C. botulinum using the flagellin variable region. PMID:17351097

Flagellin diversity in Clostridium botulinum groups I and II: a new strategy for strain identification.

Science.gov (United States)

Paul, Catherine J; Twine, Susan M; Tam, Kevin J; Mullen, James A; Kelly, John F; Austin, John W; Logan, Susan M

2007-05-01

Strains of Clostridium botulinum are traditionally identified by botulinum neurotoxin type; however, identification of an additional target for typing would improve differentiation. Isolation of flagellar filaments and analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that C. botulinum produced multiple flagellin proteins. Nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) analysis of in-gel tryptic digests identified peptides in all flagellin bands that matched two homologous tandem flagellin genes identified in the C. botulinum Hall A genome. Designated flaA1 and flaA2, these open reading frames encode the major structural flagellins of C. botulinum. Colony PCR and sequencing of flaA1/A2 variable regions classified 80 environmental and clinical strains into group I or group II and clustered isolates into 12 flagellar types. Flagellar type was distinct from neurotoxin type, and epidemiologically related isolates clustered together. Sequencing a larger PCR product, obtained during amplification of flaA1/A2 from type E strain Bennett identified a second flagellin gene, flaB. LC-MS analysis confirmed that flaB encoded a large type E-specific flagellin protein, and the predicted molecular mass for FlaB matched that observed by SDS-PAGE. In contrast, the molecular mass of FlaA was 2 to 12 kDa larger than the mass predicted by the flaA1/A2 sequence of a given strain, suggesting that FlaA is posttranslationally modified. While identification of FlaB, and the observation by SDS-PAGE of different masses of the FlaA proteins, showed the flagellin proteins of C. botulinum to be diverse, the presence of the flaA1/A2 gene in all strains examined facilitates single locus sequence typing of C. botulinum using the flagellin variable region.

Syntrophic co-culture of aerobic Bacillus and anaerobic Clostridium for bio-fuels and bio-hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Chang, Jui-Jen; Ho, Cheng-Yu.; Chen, Wei-En; Huang, Chieh-Chen [Department of Life Sciences, National Chung Hsing University, Taichung (China); Chou, Chia-Hung; Lay, Jiunn-Jyi [Department of Science and Technology, National Kaohsiung First University, Kaohsiung (China)

2008-10-15

By using brewery yeast waste and microflora from rice straw compost, an anaerobic semi-solid bio-hydrogen-producing system has been established. For the purpose of industrialization, the major players of both aerobic and anaerobic bacterial strains in the system were isolated and their combination for an effective production of bio-hydrogen and other bio-fuels was examined in this study. The phylogenetic analysis found that four anaerobic isolates (Clostridium beijerinckii L9, Clostridium diolis Z2, Clostridium roseum Z5-1, and C. roseum W8) were highly related with each other and belongs to the cluster I clostridia family, the family that many of solvent-producing strains included. On the other hand, one of the aerobic isolates, the Bacillus thermoamylovorans strain I, shown multiple extracellular enzyme activities including lipase, protease, {alpha}-amylase, pectinase and cellulase, was suggested as a good partner for creating an anaerobic environment and pre-saccharification of substrate for those co-cultured solventogenic clostridial strain. Among these clostridial strains, though C. beijerinckii L9 do not show as many extracellular enzyme activities as Bacillus, but it performs the highest hydrogen-producing ability. The original microflora can be updated to a syntrophic bacterial co-culture system contended only with B. thermoamylovorans I and C. beijerinckii L9. The combination of aerobic Bacillus and anaerobic Clostridium may play the key role for developing the industrialized bio-fuels and bio-hydrogen-producing system from biomass. (author)

Diverse taxa of cyanobacteria produce β-N-methylamino-l-alanine, a neurotoxic amino acid

OpenAIRE

Cox, Paul Alan; Banack, Sandra Anne; Murch, Susan J.; Rasmussen, Ulla; Tien, Georgia; Bidigare, Robert Richard; Metcalf, James S.; Morrison, Louise F.; Codd, Geoffrey A.; Bergman, Birgitta

2005-01-01

Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, β-N-methylamino-l-alanine, may be produced by all known groups of cyanobacteria...

Selection of tannase-producing Aspergillus niger strains

OpenAIRE

Pinto,Gustavo A.S.; Leite,Selma G.F.; Terzi,Selma C.; Couri,Sonia

2001-01-01

The aim of this work was to select strains of Aspergillus niger for tannase production. Growth of colonies in plates with tannic acid-containing medium indicated their ability to synthesize tannase. Tannase activity was also measured in solid-state fermentation. A. niger 11T25A5 was the best tannase producer (67.5 U.g-1/72 hours of fermentation).

Phylogeography of cylindrospermopsin and paralytic shellfish toxin-producing nostocales cyanobacteria from mediterranean europe (Spain).

Science.gov (United States)

Cirés, Samuel; Wörmer, Lars; Ballot, Andreas; Agha, Ramsy; Wiedner, Claudia; Velázquez, David; Casero, María Cristina; Quesada, Antonio

2014-02-01

Planktonic Nostocales cyanobacteria represent a challenge for microbiological research because of the wide range of cyanotoxins that they synthesize and their invasive behavior, which is presumably enhanced by global warming. To gain insight into the phylogeography of potentially toxic Nostocales from Mediterranean Europe, 31 strains of Anabaena (Anabaena crassa, A. lemmermannii, A. mendotae, and A. planctonica), Aphanizomenon (Aphanizomenon gracile, A. ovalisporum), and Cylindrospermopsis raciborskii were isolated from 14 freshwater bodies in Spain and polyphasically analyzed for their phylogeography, cyanotoxin production, and the presence of cyanotoxin biosynthesis genes. The potent cytotoxin cylindrospermopsin (CYN) was produced by all 6 Aphanizomenon ovalisporum strains at high levels (5.7 to 9.1 μg CYN mg(-1) [dry weight]) with low variation between strains (1.5 to 3.9-fold) and a marked extracellular release (19 to 41% dissolved CYN) during exponential growth. Paralytic shellfish poisoning (PSP) neurotoxins (saxitoxin, neosaxitoxin, and decarbamoylsaxitoxin) were detected in 2 Aphanizomenon gracile strains, both containing the sxtA gene. This gene was also amplified in non-PSP toxin-producing Aphanizomenon gracile and Aphanizomenon ovalisporum. Phylogenetic analyses supported the species identification and confirmed the high similarity of Spanish Anabaena and Aphanizomenon strains with other European strains. In contrast, Cylindrospermopsis raciborskii from Spain grouped together with American strains and was clearly separate from the rest of the European strains, raising questions about the current assumptions of the phylogeography and spreading routes of C. raciborskii. The present study confirms that the nostocalean genus Aphanizomenon is a major source of CYN and PSP toxins in Europe and demonstrates the presence of the sxtA gene in CYN-producing Aphanizomenon ovalisporum.

Characterisation of the exopolysaccharide (EPS)-producing Lactobacillus paraplantarum BGCG11 and its non-EPS producing derivative strains as potential probiotics.

Science.gov (United States)

Nikolic, Milica; López, Patricia; Strahinic, Ivana; Suárez, Ana; Kojic, Milan; Fernández-García, María; Topisirovic, Ljubisa; Golic, Natasa; Ruas-Madiedo, Patricia

2012-08-17

Traditional fermented foods are the best source for the isolation of strains with specific traits to act as functional starters and to keep the biodiversity of the culture collections. Besides, these strains could be used in the formulation of foods claimed to promote health benefits, i.e. those containing probiotic microorganisms. For the rational selection of strains acting as probiotics, several in vitro tests have been proposed. In the current study, we have characterized the probiotic potential of the strain Lactobacillus paraplantarum BGCG11, isolated from a Serbian soft, white, homemade cheese, which is able to produce a "ropy" exopolysaccharide (EPS). Three novobiocin derivative strains, which have lost the ropy phenotype, were characterized as well in order to determine the putative role of the EPS in the probiotic potential. Under chemically gastrointestinal conditions, all strains were able to survive around 1-2% (10(6)-10(7)cfu/ml cultivable bacteria) only when they were included in a food matrix (1% skimmed milk). The strains were more resistant to acid conditions than to bile salts and gastric or pancreatic enzymes, which could be due to a pre-adaptation of the parental strain to acidic conditions in the cheese habitat. The ropy EPS did not improve the survival of the producing strain. On the contrary, the presence of an EPS layer surrounding the strain BGCG11 hindered its adhesion to the three epithelial intestinal cell lines tested, since the adhesion of the three non-ropy derivatives was higher than the parental one and also than that of the reference strain Lactobacillus rhamnosus GG. Aiming to propose a potential target application of these strains as probiotics, the cytokine production of peripheral blood mononuclear cells (PBMC) was analyzed. The EPS-producing L. paraplantarum BGCG11 strain showed an anti-inflammatory or immunosuppressor profile whereas the non-ropy derivative strains induced higher pro-inflammatory response. In addition, when

Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits.

Science.gov (United States)

Voon, W W Y; Rukayadi, Y; Meor Hussin, A S

2016-05-01

Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively. Biocellulose (BC) is pure extracellular cellulose that is formed by many micro-organisms in the presence of carbon source and acidic condition. It can replace plant-based cellulose in multifarious applications due to its unique characteristics. In this study, three potential biocellulose-producing bacterial strains were obtained from Malaysian acidic fruits and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. This study reports for the first time the new biocellulose-producing bacterial strains isolated from Malaysian acidic fruits. © 2016 The

Egg yolk antibodies for detection and neutralization of Clostridium botulinum type A neurotoxin.

Science.gov (United States)

Trott, D L; Yang, M; Gonzalez, J; Larson, A E; Tepp, W H; Johnson, E A; Cook, M E

2009-05-01

The objective of this research project was to determine the usefulness of an egg antibody platform for producing materials for the detection and neutralization of botulinum type A neurotoxin. Yield estimates for detection and neutralizing antibodies produced using methods described were calculated. Antibody specific to botulinum toxoid A (aToxoid) and toxin A (aBoNT/A) was produced by immunizing hens with botulinum toxoid A (toxoid) followed by increasing amounts of botulinum neurotoxin A (BoNT/A) in Freund incomplete adjuvant. Egg yolks were extracted with polyethylene glycol (PEG) for antibody detection and neutralization experiments. A model aToxoid/toxoid immunoassay using only egg yolk antibody was developed and had a detection limit of 1 pg/ml of toxoid. In an indirect enzyme-linked immunosorbent assay of BoNT/A-specific antibody, the aBoNT/A contained more BoNT/A-specific antibody than did the aToxoid, and aBoNT/A was as effective as commercial rabbit antibody. The aToxoid provided no protection against BoNT/A in a standard mouse neutralization assay; however, 1 mg of PEG-extracted aBoNT/A neutralized 4,000 lethal doses of BoNT/A injected intraperitoneally. Based on these results, we calculated that in 1 month one hen could produce more than 100 liters of antibody detection reagents or enough antibody to neutralize approximately 11.6 million mouse lethal doses of botulinum toxin. Utilization of an egg antibody platform is potentially rapid (28 to 70 days) and scalable to kilogram quantities using current egg production facilities with as few as 1,000 hens.

Lichenysin is produced by most Bacillus licheniformis strains.

Science.gov (United States)

Madslien, E H; Rønning, H T; Lindbäck, T; Hassel, B; Andersson, M A; Granum, P E

2013-10-01

The aim of this study was to elucidate the prevalence of lichenysin production in Bacillus licheniformis and to see whether this feature was restricted to certain genotypes. Secondly, we wanted to see whether cytotoxicity reflected the measured levels of lichenysin. Fifty-three genotyped strains of B. licheniformis, representing a wide variety of sources, were included. lchAA gene fragments were detected in all strains by polymerase chain reaction (PCR). All 53 strains produced lichenysins with four molecular masses as confirmed by LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis. The amounts of lichenysin varied more than two orders of magnitude between strains and were irrespective of genotype. Finally, there was a strong association between lichenysin concentrations and toxicity towards boar spermatozoa, erythrocytes and Vero cells. Lichenysin synthesis was universal among the 53 B. licheniformis strains examined. The quantities varied considerably between strains, but were not specifically associated with genotype. Cytotoxicity was evident at lichenysin concentrations above 10 μg ml(-1) , which is in accordance with previous studies. This study might be of interest to those working on B. licheniformis for commercial use as well as for authorities who make risk assessments of B. licheniformis when used as a food and feed additive. © 2013 The Society for Applied Microbiology.

Botulinum neurotoxin formulations: overcoming the confusion

Directory of Open Access Journals (Sweden)

Samizadeh S

2018-05-01

Full Text Available Souphiyeh Samizadeh,1 Koenraad De Boulle2 1Great British Academy of Aesthetic Medicine, London, UK; 2Aalst Dermatology Clinic, Aalst, Belgium Abstract: Botulinum toxin A is produced by anaerobic spore-forming bacteria and is used for various therapeutic and cosmetic purposes. Botulinum toxin A injections are the most popular nonsurgical procedure worldwide. Despite an increased demand for botulinum toxin A injections, the clinical pharmacology and differences in formulation of commonly available products are poorly understood. The various products available in the market are unique and vary in terms of units, chemical properties, biological activities, and weight, and are therefore not interchangeable. For safe clinical practice and to achieve optimal results, the practitioners need to understand the clinical issues of potency, conversion ratio, and safety issues (toxin spread and immunogenicity. In this paper, the basic clinical pharmacology of botulinum toxin A and differences between onabotulinum toxin A, abobotulinum toxin A, and incobotulinum toxin A are discussed. Keywords: botulinum toxin, botulinum neurotoxin, moiety, protein complexes

A novel neurotoxin from venom of the spider, Brachypelma albopilosum.

Directory of Open Access Journals (Sweden)

Yunhua Zhong

Full Text Available Spiders have evolved highly selective toxins for insects. There are many insecticidal neurotoxins in spider venoms. Although a large amount of work has been done to focus on neurotoxicity of spider components, little information, which is related with effects of spider toxins on tumor cell proliferation and cytotoxicity, is available for Brachypelma albopilosum venom. In this work, a novel spider neurotoxin (brachyin was identified and characterized from venoms of the spider, Brachypelma albopilosum. Brachyin is composed of 41 amino acid residues with the sequence of CLGENVPCDKDRPNCCSRYECLEPTGYGWWYASYYCYKKRS. There are six cysteines in this sequence, which form three disulfided bridges. The serine residue at the C-terminus is amidated. Brachyin showed strong lethal effects on American cockroaches (Periplaneta americana and Tenebrio molitor (common mealbeetle. This neurotoxin also showed significant analgesic effects in mice models including abdominal writhing induced by acetic acid and formalin-induced paw licking tests. It was interesting that brachyin exerted marked inhibition on tumor cell proliferation.

Effects of Cylindrospermopsis raciborskii strains (Woloszynska, 1912 Senayya & Subba Raju on the mobility of Daphnia laevis (Cladocera, Daphniidae

Directory of Open Access Journals (Sweden)

GC Restani

Full Text Available Cylindrospermopsis raciborskii is a cyanobacterium distributed worldwide that is known to produce cyanotoxins. Some of the Brazilian strains can produce saxitoxins (STXs, which are classified as neurotoxins and can paralyze cladocerans .Daphnia laevis is a cladoceran with a wide distribution in the Americas and has been studied as a possible test-organism in toxicity bioassays. The present work tested the acute effect on D laevis mobility when fed a saxitoxin-producing (STX and neoSTX C. raciborskii strain, CYRF-01, and compared the results with the effects of a non-toxic strain (NPCS-1. Neonates (6-24 hours after birth were exposed to concentrations of C. raciborskii varying from 102 to 106 cells·mL–1 of each strain for up to three hours. The cladocerans were then transferred to a medium without toxic filaments for 24 hours. Only the organisms exposed to the STX-producing strain showed signs of the immobilization of swimming movements, confirming the effects of the toxins. There was a linear correlation between the time required to induce stopping the swimming movement, with a shorter time to needed to induce immobilization at a higher the concentration; this correlation was inverse to the time required to recover the swimming movements (longer at higher concentrations, p < 0.1. D. laevis is a tropical and subtropical species with great potential for use in toxicity tests for the detection of STXs, despite being native to and found in a great array of freshwater bodies. This is the first assay testing STX-producing and non-producing C. raciborskii strains on D. laevis, species that are both found in Brazilian ecosystems.

Effects of Cylindrospermopsis raciborskii strains (Woloszynska, 1912) Senayya & Subba Raju on the mobility of Daphnia laevis (Cladocera, Daphniidae).

Science.gov (United States)

Restani, G C; Fonseca, A L

2014-02-01

Cylindrospermopsis raciborskii is a cyanobacterium distributed worldwide that is known to produce cyanotoxins. Some of the Brazilian strains can produce saxitoxins (STXs), which are classified as neurotoxins and can paralyze cladocerans .Daphnia laevis is a cladoceran with a wide distribution in the Americas and has been studied as a possible test-organism in toxicity bioassays. The present work tested the acute effect on D laevis mobility when fed a saxitoxin-producing (STX and neoSTX) C. raciborskii strain, CYRF-01, and compared the results with the effects of a non-toxic strain (NPCS-1). Neonates (6-24 hours after birth) were exposed to concentrations of C. raciborskii varying from 102 to 106 cells·mL-1 of each strain for up to three hours. The cladocerans were then transferred to a medium without toxic filaments for 24 hours. Only the organisms exposed to the STX-producing strain showed signs of the immobilization of swimming movements, confirming the effects of the toxins. There was a linear correlation between the time required to induce stopping the swimming movement, with a shorter time to needed to induce immobilization at a higher the concentration; this correlation was inverse to the time required to recover the swimming movements (longer at higher concentrations, p < 0.1). D. laevis is a tropical and subtropical species with great potential for use in toxicity tests for the detection of STXs, despite being native to and found in a great array of freshwater bodies. This is the first assay testing STX-producing and non-producing C. raciborskii strains on D. laevis, species that are both found in Brazilian ecosystems.

sxtA-based quantitative molecular assay to identify saxitoxin-producing harmful algal blooms in marine waters.

Science.gov (United States)

Murray, Shauna A; Wiese, Maria; Stüken, Anke; Brett, Steve; Kellmann, Ralf; Hallegraeff, Gustaaf; Neilan, Brett A

2011-10-01

The recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the chemical ecology of harmful algal blooms in situ. We present a novel method for detecting and quantifying the potential for STX production in marine environmental samples. Our assay detects a domain of the gene sxtA that encodes a unique enzyme putatively involved in the sxt pathway in marine dinoflagellates, sxtA4. A product of the correct size was recovered from nine strains of four species of STX-producing Alexandrium and Gymnodinium catenatum and was not detected in the non-STX-producing Alexandrium species, other dinoflagellate cultures, or an environmental sample that did not contain known STX-producing species. However, sxtA4 was also detected in the non-STX-producing strain of Alexandrium tamarense, Tasmanian ribotype. We investigated the copy number of sxtA4 in three strains of Alexandrium catenella and found it to be relatively constant among strains. Using our novel method, we detected and quantified sxtA4 in three environmental blooms of Alexandrium catenella that led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine samples and will be useful for biological oceanographic research and harmful algal bloom monitoring.

Researchers unmask secret to long-lasting effects of botulinum neurotoxin A in motor neurons | Center for Cancer Research

Science.gov (United States)

A team of scientists led by the Center for Cancer Research's Allan M. Weissman, M.D., and Yien Che Tsai, Ph.D., has discovered a molecular mechanism that explains the extreme toxicity of botulinum neurotoxin A (BoNT/A), the most potent BoNT strain. The discovery, published June 5 in PNAS, also identifies a molecular target that the researchers hope will eventually lead to improved therapies to treat exposure and severely undermine the potential use of BoNTs as bioweapons.  Read more...  

The neurotoxin BMAA in aquatic systems

NARCIS (Netherlands)

Faassen, E.J.

2016-01-01

Eutrophication is a major water quality issue and in many aquatic systems, it leads to the proliferation of toxic phytoplankton species. The neurotoxin β-N-methylamino-L-alanine (BMAA) is one of the compounds that can be present in phytoplankton. BMAA has been suggested to play a role in

On the translocation of botulinum and tetanus neurotoxins across the membrane of acidic intracellular compartments.

Science.gov (United States)

Pirazzini, Marco; Azarnia Tehran, Domenico; Leka, Oneda; Zanetti, Giulia; Rossetto, Ornella; Montecucco, Cesare

2016-03-01

Tetanus and botulinum neurotoxins are produced by anaerobic bacteria of the genus Clostridium and are the most poisonous toxins known, with 50% mouse lethal dose comprised within the range of 0.1-few nanograms per Kg, depending on the individual toxin. Botulinum neurotoxins are similarly toxic to humans and can therefore be considered for potential use in bioterrorism. At the same time, their neurospecificity and reversibility of action make them excellent therapeutics for a growing and heterogeneous number of human diseases that are characterized by a hyperactivity of peripheral nerve terminals. The complete crystallographic structure is available for some botulinum toxins, and reveals that they consist of four domains functionally related to the four steps of their mechanism of neuron intoxication: 1) binding to specific receptors of the presynaptic membrane; 2) internalization via endocytic vesicles; 3) translocation across the membrane of endocytic vesicles into the neuronal cytosol; 4) catalytic activity of the enzymatic moiety directed towards the SNARE proteins. Despite the many advances in understanding the structure-mechanism relationship of tetanus and botulinum neurotoxins, the molecular events involved in the translocation step have been only partially elucidated. Here we will review recent advances that have provided relevant insights on the process and discuss possible models that can be experimentally tested. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale. Copyright © 2015. Published by Elsevier B.V.

Pharmaceutical, biological, and clinical properties of botulinum neurotoxin type A products.

Science.gov (United States)

Frevert, Jürgen

2015-03-01

Botulinum neurotoxin injections are a valuable treatment modality for many therapeutic indications and have revolutionized the field of aesthetic medicine so that they are the leading cosmetic procedure performed worldwide. Studies show that onabotulinumtoxinA, abobotulinumtoxinA, and incobotulinumtoxinA are comparable in terms of clinical efficacy. Differences between the products relate to the botulinum neurotoxin complexes, specific biological potency, and their immunogenicity. Protein complex size and molecular weight have no effect on biological activity, stability, distribution, or side effect profile. Complexing proteins and inactive toxin (toxoid) content increase the risk of neutralizing antibody formation, which can cause secondary treatment failure, particularly in chronic disorders that require frequent injections and long-term treatment. These attributes could lead to differences in therapeutic outcomes, and, given the widespread aesthetic use of these three neurotoxin products, physicians should be aware of how they differ to ensure their safe and effective use.

Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.

Directory of Open Access Journals (Sweden)

Xin Tang

Full Text Available The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA; however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11 isolated in this laboratory can produce lipid up to 36% (w/w cell dry weight (CDW. We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.

Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.

Science.gov (United States)

Tang, Xin; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

2015-01-01

The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA); however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11) isolated in this laboratory can produce lipid up to 36% (w/w) cell dry weight (CDW). We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w) lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL) to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.

Excitatory amino acid b-N-methylamino-L-alanine is a putative environmental neurotoxin

Directory of Open Access Journals (Sweden)

VLADIMIR NEDELJKOV

2011-04-01

Full Text Available The amino acid b-N-methylamino-L-alanine (L-BMAA has been associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex in three distinct western Pacific populations. The putative neurotoxin is produced by cyanobacteria, which live symbiotically in the roots of cycad trees. L-BMAA was thought to be a threat only to those few populations whose diet and medicines rely heavily on cycad seeds. However, the recent discovery that cyanobacteria from diverse terrestrial, freshwater, and saltwater ecosystems around the world produce the toxin requires a reassessment of whether it poses a larger health threat. Therefore, it is proposed that monitoring L-BMAA levels in cyanobacteria-contaminated water supplies might be prudent.

Pseudomonas cremoricolorata Strain ND07 Produces N-acyl Homoserine Lactones as Quorum Sensing Molecules

Directory of Open Access Journals (Sweden)

Nina Yusrina Muhamad Yunos

2014-06-01

Full Text Available Quorum sensing (QS is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs. We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-l-homoserine lactone (C8-HSL and N-decanoyl-l-homoserine lactone (C10-HSL. To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

[Genetic modification of Methylobacterium extorquens G10 producer strain of polyhydroxybutyrate].

Science.gov (United States)

Fedorov, D N; Zamakhaeva, S A; Ezhov, V A; Doronina, N V; Trotsenko, Iu A

2014-01-01

The effect of the increased copy number of polyhydroxybutyrate (PHB) biosynthesis genes in pink-pigmented methylobacterium Methylobacterium extorquens G10 on properties of the biopolymer was studied. The activity of poly-3-hydroxybutyril-synthase (PHB-synthase) was shown to increase and the molecular weight of synthesized PHB decreases twofold (150 --> 79 kDa) after insertion of extra copies of phaC and phaCAB genes into cells of the producer strain, whereas the physicochemical properties of the plastic changed insignificantly. White mutant M. extorquens G10-W with disrupted synthesis of the carotenoid pigment (defect by the crtI gene, which codes for phytoene desaturase) was established to have the same rate of growth and level of PHB accumulation as the initial strain G10. The G10-W strain is a promising producer of PHB, with decreased expenses for purification and PHB biosynthesis.

Structural and functional characterization of a novel homodimeric three-finger neurotoxin from the venom of Ophiophagus hannah (king cobra).

Science.gov (United States)

Roy, Amrita; Zhou, Xingding; Chong, Ming Zhi; D'hoedt, Dieter; Foo, Chun Shin; Rajagopalan, Nandhakishore; Nirthanan, Selvanayagam; Bertrand, Daniel; Sivaraman, J; Kini, R Manjunatha

2010-03-12

Snake venoms are a mixture of pharmacologically active proteins and polypeptides that have led to the development of molecular probes and therapeutic agents. Here, we describe the structural and functional characterization of a novel neurotoxin, haditoxin, from the venom of Ophiophagus hannah (King cobra). Haditoxin exhibited novel pharmacology with antagonism toward muscle (alphabetagammadelta) and neuronal (alpha(7), alpha(3)beta(2), and alpha(4)beta(2)) nicotinic acetylcholine receptors (nAChRs) with highest affinity for alpha(7)-nAChRs. The high resolution (1.5 A) crystal structure revealed haditoxin to be a homodimer, like kappa-neurotoxins, which target neuronal alpha(3)beta(2)- and alpha(4)beta(2)-nAChRs. Interestingly however, the monomeric subunits of haditoxin were composed of a three-finger protein fold typical of curaremimetic short-chain alpha-neurotoxins. Biochemical studies confirmed that it existed as a non-covalent dimer species in solution. Its structural similarity to short-chain alpha-neurotoxins and kappa-neurotoxins notwithstanding, haditoxin exhibited unique blockade of alpha(7)-nAChRs (IC(50) 180 nm), which is recognized by neither short-chain alpha-neurotoxins nor kappa-neurotoxins. This is the first report of a dimeric short-chain alpha-neurotoxin interacting with neuronal alpha(7)-nAChRs as well as the first homodimeric three-finger toxin to interact with muscle nAChRs.

Injectable neurotoxins and fillers: there is no free lunch.

Science.gov (United States)

Emer, Jason; Waldorf, Heidi

2011-01-01

Injection of neurotoxins and filling agents for the treatment of facial aesthetics has increased dramatically during the past few decades due to an increased interest in noninvasive aesthetic improvements. An aging but still youth-oriented population expects effective treatments with minimal recovery time and limited risk of complications. Injectable neurotoxins and soft tissue stimulators and fillers have filled this niche of "lunch-time" procedures. As demand for these procedures has increased, supply has followed with more noncore cosmetic specialty physicians, as well as unsupervised ancillary staff, becoming providers and advertising them as easy fixes. Despite an excellent record of safety and efficacy demonstrated in scores of published studies, injectable agents do carry risks of complications. These procedures require a physician with in-depth knowledge of facial anatomy and injection techniques to ensure patient safety and satisfaction. In general, adverse events are preventable and technique-dependent. Although most adverse events are minor and temporary, more serious complications can occur. The recognition, management, and treatment of poor outcomes are as important as obtaining the best aesthetic results. This review addresses important considerations regarding the complications of injectable neurotoxins and fillers used for "lunch-time" injectable procedures. Copyright © 2011 Elsevier Inc. All rights reserved.

sxtA-Based Quantitative Molecular Assay To Identify Saxitoxin-Producing Harmful Algal Blooms in Marine Waters ▿ †

Science.gov (United States)

Murray, Shauna A.; Wiese, Maria; Stüken, Anke; Brett, Steve; Kellmann, Ralf; Hallegraeff, Gustaaf; Neilan, Brett A.

2011-01-01

The recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the chemical ecology of harmful algal blooms in situ. We present a novel method for detecting and quantifying the potential for STX production in marine environmental samples. Our assay detects a domain of the gene sxtA that encodes a unique enzyme putatively involved in the sxt pathway in marine dinoflagellates, sxtA4. A product of the correct size was recovered from nine strains of four species of STX-producing Alexandrium and Gymnodinium catenatum and was not detected in the non-STX-producing Alexandrium species, other dinoflagellate cultures, or an environmental sample that did not contain known STX-producing species. However, sxtA4 was also detected in the non-STX-producing strain of Alexandrium tamarense, Tasmanian ribotype. We investigated the copy number of sxtA4 in three strains of Alexandrium catenella and found it to be relatively constant among strains. Using our novel method, we detected and quantified sxtA4 in three environmental blooms of Alexandrium catenella that led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine samples and will be useful for biological oceanographic research and harmful algal bloom monitoring. PMID:21841034

CRISPR/Cas9-Mediated Genomic Deletion of the Beta-1, 4 N-acetylgalactosaminyltransferase 1 Gene in Murine P19 Embryonal Carcinoma Cells Results in Low Sensitivity to Botulinum Neurotoxin Type C.

Directory of Open Access Journals (Sweden)

Kentaro Tsukamoto

Full Text Available Botulinum neurotoxins produced by Clostridium botulinum cause flaccid paralysis by inhibiting neurotransmitter release at peripheral nerve terminals. Previously, we found that neurons derived from the murine P19 embryonal carcinoma cell line exhibited high sensitivity to botulinum neurotoxin type C. In order to prove the utility of P19 cells for the study of the intracellular mechanism of botulinum neurotoxins, ganglioside-knockout neurons were generated by deletion of the gene encoding beta-1,4 N-acetylgalactosaminyltransferase 1 in P19 cells using the clustered regularly interspaced short palindromic repeats combined with Cas9 (CRISPR/Cas9 system. By using this system, knockout cells could be generated more easily than with previous methods. The sensitivity of the generated beta-1,4 N-acetylgalactosaminyltransferase 1-depleted P19 neurons to botulinum neurotoxin type C was decreased considerably, and the exogenous addition of the gangliosides GD1a, GD1b, and GT1b restored the susceptibility of P19 cells to botulinum neurotoxin type C. In particular, addition of a mixture of these three ganglioside more effectively recovered the sensitivity of knockout cells compared to independent addition of GD1a, GD1b, or GT1b. Consequently, the genome-edited P19 cells generated by the CRISPR/Cas9 system were useful for identifying and defining the intracellular molecules involved in the toxic action of botulinum neurotoxins.

Aflatoxin B1 producing potential of Aspergillus flavus strains isolated ...

African Journals Online (AJOL)

STORAGESEVER

2009-07-20

Jul 20, 2009 ... consumption of aflatoxin contaminated food and feed. (Reddy and ..... intervals by artificial inoculation of A. parasiticus on rice grains. ... additive for culture media for rapid identification of aflatoxin producing. Aspergillus strains ...

Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

Directory of Open Access Journals (Sweden)

Abdelahhad Barbour

Full Text Available BACKGROUND: Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS. A new medium for maximum biomass production buffered with 2-(N-morpholinoethanesulfonic acid (MES was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10 and salivaricin G32 (by strain YU10 from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. CONCLUSION: The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for

Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

Science.gov (United States)

Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines w...

Recovery of succinic acid produced by fermentation of a metabolically engineered Mannheimia succiniciproducens strain.

Science.gov (United States)

Song, Hyohak; Huh, Yun Suk; Lee, Sang Yup; Hong, Won Hi; Hong, Yeon Ki

2007-12-01

There have recently been much advances in the production of succinic acid, an important four-carbon dicarboxylic acid for many industrial applications, by fermentation of several natural and engineered bacterial strains. Mannheimia succiniciproducens MBEL55E isolated from bovine rumen is able to produce succinic acid with high efficiency, but also produces acetic, formic and lactic acids just like other anaerobic succinic acid producers. We recently reported the development of an engineered M. succiniciproducens LPK7 strain which produces succinic acid as a major fermentation product while producing much reduced by-products. Having an improved succinic acid producer developed, it is equally important to develop a cost-effective downstream process for the recovery of succinic acid. In this paper, we report the development of a simpler and more efficient method for the recovery of succinic acid. For the recovery of succinic acid from the fermentation broth of LPK7 strain, a simple process composed of a single reactive extraction, vacuum distillation, and crystallization yielded highly purified succinic acid (greater than 99.5% purity, wt%) with a high yield of 67.05wt%. When the same recovery process or even multiple reactive extraction steps were applied to the fermentation broth of MBEL55E, lower purity and yield of succinic acid were obtained. These results suggest that succinic acid can be purified in a cost-effective manner by using the fermentation broth of engineered LPK7 strain, showing the importance of integrating the strain development, fermentation and downstream process for optimizing the whole processes for succinic acid production.

What is the risk of aluminium as a neurotoxin?

Science.gov (United States)

Exley, Christopher

2014-06-01

Aluminium is neurotoxic. Its free ion, Al(3+) (aq), is highly biologically reactive and uniquely equipped to do damage to essential cellular (neuronal) biochemistry. This unequivocal fact must be the starting point in examining the risk posed by aluminium as a neurotoxin in humans. Aluminium is present in the human brain and it accumulates with age. The most recent research demonstrates that a significant proportion of individuals older than 70 years of age have a potentially pathological accumulation of aluminium somewhere in their brain. What are the symptoms of chronic aluminium intoxication in humans? What if neurodegenerative diseases such as Alzheimer's disease are the manifestation of the risk of aluminium as a neurotoxin? How might such an (outrageous) hypothesis be tested?

[GM1-dot-EIA for the detection of toxin-producing Vibrio cholerae strains].

Science.gov (United States)

Markina, O V; Alekseeva, L P; Telesmanich, N R; Chemisova, O S; Akulova, M V; Markin, N V

2011-05-01

A new variant of enzyme immunoassay (EIA) has been developed on the basis of GM1 gangliosides to detect the toxin-producing Vibrio cholerae strains--GM1-dot-EIA. Experiments were run using a nitrocellulose membrane to bind GM1 gangliosides and polyclonal antitoxic serum to detect cholerogen. GM1-dot-EIA testing identified cholera toxin in 11 of 13 supernatants of V. cholerae eltor ctx(+) strains isolated from man and in 3 of 7 supernatants of V. cholerae eltor ctx(+) strains isolated from water. These data agree with those obtained in CM1-EIA. There was no reaction with the supernatants of other microorganisms. The sensitivity of the technique was 10 ng/ml. Thus, the simple and specific GM1-dot-EIA may be recommended to detect toxin-producing V cholerae strains isolated from man and water.

Production and characterisation of a neutralising chimeric antibody against botulinum neurotoxin A.

Directory of Open Access Journals (Sweden)

Julie Prigent

Full Text Available Botulinum neurotoxins, produced by Clostridium botulinum bacteria, are the causative agent of botulism. This disease only affects a few hundred people each year, thus ranking it among the orphan diseases. However, botulinum toxin type A (BoNT/A is the most potent toxin known to man. Due to their potency and ease of production, these toxins were classified by the Centers for Disease Control and Prevention (CDC as Category A biothreat agents. For several biothreat agents, like BoNT/A, passive immunotherapy remains the only possible effective treatment allowing in vivo neutralization, despite possible major side effects. Recently, several mouse monoclonal antibodies directed against a recombinant fragment of BoNT/A were produced in our laboratory and most efficiently neutralised the neurotoxin. In the present work, the most powerful one, TA12, was selected for chimerisation. The variable regions of this antibody were thus cloned and fused with the constant counterparts of human IgG1 (kappa light and gamma 1 heavy chains. Chimeric antibody production was evaluated in mammalian myeloma cells (SP2/0-Ag14 and insect cells (Sf9. After purifying the recombinant antibody by affinity chromatography, the biochemical properties of chimeric and mouse antibody were compared. Both have the same very low affinity constant (close to 10 pM and the chimeric antibody exhibited a similar capacity to its parent counterpart in neutralising the toxin in vivo. Its strong affinity and high neutralising potency make this chimeric antibody interesting for immunotherapy treatment in humans in cases of poisoning, particularly as there is a probable limitation of the immunological side effects observed with classical polyclonal antisera from heterologous species.

CHARACTERIZATION OF EXTENDED-SPECTRUM Β-LACTAMASE-PRODUCING ESCHERICHIA COLI STRAINS ISOLATED FROM DAIRY PRODUCTS

Directory of Open Access Journals (Sweden)

Rahem Khoshbakht

2014-02-01

Full Text Available Extended-spectrum β-lactamases (ESBLs are enzymes that hydrolyze the β-lactam ring, and ESBL-producing E. coli has rapidly spread worldwide with pose a serious hazard for humans. The aim of this study was to determine the prevalence of ESBL producing E. coli and molecular evaluation of four ESBL-associated genes among E. coli strains isolated from milk and cheese in southern Iran. Antibiotic susceptibility test was carried out for a total of 150 isolates of E. coli, previously collected from dairy products. ESBL production was screened using a double-disc synergy test (DDST and presence of four ESBL genes (PER, VEB, TEM and CTX-M was tested using PCR. Among 150 E. coli strains 57 (38% isolates were identified as ESBL-producing strains. All ESBL positive isolates could be typed for one or more genes and the most prevalent ESBL-associated gene was CTX-M (80.7%. The PER gene was not present among isolates. Isolates showed high susceptibility to imipe¬nem and cefoxitin. The results showed the high prevalence of ESBL producing E. coli strains among dairy products and high occurrence of CTX-M-associated ESBL activity among isolates indicating the hazards of increasing the strains with antibiotic resistance which can transfer to human trough the dairy food products.

RNA aptasensor for rapid detection of natively folded type A botulinum neurotoxin.

Science.gov (United States)

Janardhanan, Pavithra; Mello, Charlene M; Singh, Bal Ram; Lou, Jianlong; Marks, James D; Cai, Shuowei

2013-12-15

A surface plasmon resonance based RNA aptasensor for rapid detection of natively folded type A botulinum neurotoxin is reported. Using detoxified recombinant type A botulinum neurotoxin as the surrogate, the aptasensor detects active toxin within 90 min. The detection limit of the aptasensor in phosphate buffered saline, carrot juice, and fat free milk is 5.8 ng/ml, 20.3 ng/ml and 23.4 ng/ml, respectively, while that in 5-fold diluted human serum is 22.5 ng/ml. Recovery of toxin from disparate sample matrices are within 91-116%. Most significant is the ability of this aptasensor to effectively differentiate the natively folded toxin from denatured, inactive toxin, which is important for homeland security surveillance and threat assessment. The aptasensor is stable for more than 30 days and over 400 injections/regeneration cycles. Such an aptasensor holds great promise for rapid detection of active botulinum neurotoxin for field surveillance due to its robustness, stability and reusability. © 2013 Elsevier B.V. All rights reserved.

Diverse taxa of cyanobacteria produce beta-N-methylamino-L-alanine, a neurotoxic amino acid.

Science.gov (United States)

Cox, Paul Alan; Banack, Sandra Anne; Murch, Susan J; Rasmussen, Ulla; Tien, Georgia; Bidigare, Robert Richard; Metcalf, James S; Morrison, Louise F; Codd, Geoffrey A; Bergman, Birgitta

2005-04-05

Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, beta-N-methylamino-L-alanine, may be produced by all known groups of cyanobacteria, including cyanobacterial symbionts and free-living cyanobacteria. The ubiquity of cyanobacteria in terrestrial, as well as freshwater, brackish, and marine environments, suggests a potential for wide-spread human exposure.

Diverse taxa of cyanobacteria produce β-N-methylamino-l-alanine, a neurotoxic amino acid

Science.gov (United States)

Cox, Paul Alan; Banack, Sandra Anne; Murch, Susan J.; Rasmussen, Ulla; Tien, Georgia; Bidigare, Robert Richard; Metcalf, James S.; Morrison, Louise F.; Codd, Geoffrey A.; Bergman, Birgitta

2005-01-01

Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, β-N-methylamino-l-alanine, may be produced by all known groups of cyanobacteria, including cyanobacterial symbionts and free-living cyanobacteria. The ubiquity of cyanobacteria in terrestrial, as well as freshwater, brackish, and marine environments, suggests a potential for wide-spread human exposure. PMID:15809446

Characterization of new exopolysaccharides produced by coculturing of L. kefiranofaciens with yoghurt strains.

Science.gov (United States)

Ahmed, Zaheer; Wang, Yanping; Anjum, Nomana; Ahmad, Hajra; Ahmad, Asif; Raza, Mohsin

2013-08-01

This project was designed to study the coculturing affect of exopolysaccharide (EPS) producing strains Lactobacillus kefiranofaciens (L.k) ZW3, with non EPS producing strains L. bulgaricus (L.b) and Streptococcus thermophilus (S.t) in three different combinations: L.k+L.b, L.k+S.t, and L.k+L.b+S.t. FTIR analysis revealed presence of strong stretch in regions of 3400, 2900 and 1647cm(-1) which is characteristic of a typical polysaccharide. Co-cultured EPSs were composed of glucose, galactose, arabinose and xylose; and their sugar compositions were different from ZW3 polysaccharide that was mainly composed of gluco-galactan. Peak temperature for L.k+L.b, L.k+S.t, L.k+S.t+L.b and ZW3 polymers were 90.59, 87.61, 95.18 and 97.38°C, respectively. Thermal analysis revealed degradation temperature of 326.44, 294.6, 296.7 and 299.62°C for L.k+L.b, L.k+S.t, L.k+S.t+L.b and ZW3 polymers, respectively. SEM and AFM analysis divulged that three cocultured EPSs had different surface morphology than ZW3 polymer. Since co-cultured polymers have different structure than the polymer produced exclusively by EPS producing strain, it can be safely concluded from the study that co-culturing can be one way to change the structure of polymers. Coculturing of L. kefiranofaciens with non-EPS producing strains resulted in yoghurt with increased viscosity and delayed syneresis. Copyright © 2013 Elsevier B.V. All rights reserved.

Safety Evaluation of Enterocin Producer Enterococcus sp. Strains Isolated from Traditional Turkish Cheeses.

Science.gov (United States)

Avcı, Mine; Özden Tuncer, Banu

2017-07-06

The purpose of this study was to determine the antimicrobial activity and occurrence of bacteriocin structural genes in Enterococcus spp. isolated from different cheeses and also investigate some of their virulence factors. Enterococcus strains were isolated from 33 different cheeses. Enterococcus faecium (6 strains) and Enterococcus faecalis (5 strains) enterocin-producing strains were identified by 16S rDNA analyses. Structural genes entA, entB, entP and entX were detected in some isolates. Multiple enterocin structural genes were found in 7 strains. None of the tested enterococci demonstrated anyβ-haemolytic activity and only one strain had gelatinase activity. Six strains showed multiple antibiotic resistance patterns and in addition, vanA and several virulence genes were detected in many strains. Only E. faecalis MBE1-9 showed tyrosine decarboxylase activity and tdc gene was detected only in this strain.

Draft Genome Sequence of Hoeflea sp. Strain BAL378, a Potential Producer of Bioactive Compounds

DEFF Research Database (Denmark)

Bentzon-Tilia, Mikkel; Riemann, Lasse; Gram, Lone

2014-01-01

Some phytoplankton-associated marine bacteria produce bioactive compounds. Members of the genus Hoeflea may be examples of such bacteria; however, data describing their metabolisms are scarce. Here, we report the draft genome sequence of Hoeflea sp. strain BAL378, a putative producer of bacterioc......Some phytoplankton-associated marine bacteria produce bioactive compounds. Members of the genus Hoeflea may be examples of such bacteria; however, data describing their metabolisms are scarce. Here, we report the draft genome sequence of Hoeflea sp. strain BAL378, a putative producer...

Strain diversity of CTX-M-producing Enterobacteriaceae in individual pigs

DEFF Research Database (Denmark)

Hansen, Katrine Hartung; Bortolaia, Valeria; Damborg, Peter Panduro

2014-01-01

of CTX-M-2/97-producing Proteus mirabilis or Providencia rettgeri was observed in two sows and two offspring. At least two genetically unrelated CTX-M-producing E. coli strains were isolated from approximately one fourth of the samples with remarkable differences between isolates obtained by enrichment...

Screening on the high yield validamycin producing strain by implantation with N+ and Ti+ ion source

International Nuclear Information System (INIS)

Yu Long; An Xiao

2007-01-01

In order to compared the mutagenic effects of the validamycin producing the strain (Streptomyces hygroscopicus var. Jingganggensis Yen.) was implanted with two kinds of ion sources. The results showed that when two kinds of ion sources implanted into the strain by turns, more positive mutants and higher yield would be acquired. Using this method, a high-yielding strain B1-3 was obtained, which produce the titer of validamycin A of 21514, and was 54.4% higher than that of the original strain. (authors)

Cerebrovascular Acute Radiation Syndrome : Radiation Neurotoxins, Mechanisms of Toxicity, Neuroimmune Interactions.

Science.gov (United States)

Popov, Dmitri; Maliev, Slava

. Radiation Toxins (SRD-1)had been isolated from Central Lymph of irradiated animals (cows, sheep, pigs). Experiments to study toxicity of Radiation Neurotoxins had been performed. Intravenous (IV) and intramuscular (IM) administration of RT SRD-1 to radiation naive animals had induced acute toxicity which referred to the harmful effects generated by high doses of radiation. In-jection of toxic doses of RT SRD-1 (Toxic doses: 0,1 mg/kg, 0,5mg/kg, 1 mg/kg, 10mg/kg,30 mg/kg, 50mg/kg,70 mg/kg,100 mg/kg, 110mg/kg)were compared to the similar effects caused by high doses of radiation. Results: Injection of SRD-1 ( Neurotoxin Cv ARS)of all ten tested toxic doses had caused a death of radiation naive animals within the first hours after admin-istration of toxins. For all animals in all experiments, a short period of extreme agitation was replaced by deep coma, and suppression of blood circulation and breathing. The results of postmortem section had showed characteristics of intra-cortical hemorrhage. Conclusions: Acute radiation injury induces a disorder of blood supply of the Central Nervous System (CNS). However, administration of SRD-1 Radiation Toxins to radiation naive animals produces crit-ically important inflammatory reactions with hemorrhagic stroke development. Neurotoxicity and Excitotoxicity are two stages of the pathological processes resulted in damaging and killing nerve cells thorough apoptotic necrosis. Excitotoxicity is well known as a pathological process that occurs when important excitatory neurotransmitters (glutamate, serotonin) over-activate the receptors -NMDA, AMPA, 5HT1, 5HT2, 5H3. Radiation Neurotoxins possibly act on the same receptors and activate the cell death mechanisms through direct or indirect excessive activation of same receptors.

Fusion and retrotransposition events in the evolution of the sea anemone Anemonia viridis neurotoxin genes.

Science.gov (United States)

Moran, Yehu; Weinberger, Hagar; Lazarus, Nimrod; Gur, Maya; Kahn, Roy; Gordon, Dalia; Gurevitz, Michael

2009-08-01

Sea anemones are sessile predators that use a variety of toxins to paralyze prey and foe. Among these toxins, Types I, II and III are short peptides that affect voltage-gated sodium channels. Anemonia viridis is the only sea anemone species that produces both Types I and III neurotoxin. Although the two toxin types are unrelated in sequence and three-dimensional structure, cloning and comparative analysis of their loci revealed a highly similar sequence at the 5' region, which encodes a signal peptide. This similarity was likely generated by gene fusion and could be advantageous in transcript stability and intracellular trafficking and secretion. In addition, these analyses identified the processed pseudogenes of the two gene families in the genome of A. viridis, probably resulting from retrotransposition events. As presence of processed pseudogenes in the genome requires transcription in germ-line cells, we analyzed oocyte-rich ovaries and found that indeed they contain Types I and III transcripts. This result raises questions regarding the role of toxin transcripts in these tissues. Overall, the retrotransposition and gene fusion events suggest that the genes of both Types I and III neurotoxins evolved in a similar fashion and share a partial common ancestry.

In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria.

Science.gov (United States)

Motwalli, Olaa; Essack, Magbubah; Jankovic, Boris R; Ji, Boyang; Liu, Xinyao; Ansari, Hifzur Rahman; Hoehndorf, Robert; Gao, Xin; Arold, Stefan T; Mineta, Katsuhiko; Archer, John A C; Gojobori, Takashi; Mijakovic, Ivan; Bajic, Vladimir B

2017-01-05

Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis. To our knowledge FFASC is the first

In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

KAUST Repository

Motwalli, Olaa Amin

2017-01-05

Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Results Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis. Conclusion To

Inhibition of food-related bacteria by antibacterial substances produced by Pseudomonas sp. strains isolated from pasteurized milk

Directory of Open Access Journals (Sweden)

Ana Beatriz Ferreira Rangel

2013-12-01

Full Text Available In this work, the production of antimicrobial substances by strains of Pseudomonas sp. isolated from pasteurized milk and their potential action against food-related bacteria were investigated. Samples of pasteurized milk were purchased from arbitrarily chosen commercial establishments in the city of Rio de Janeiro, Brazil. Of the four samples analyzed, three presented several typical colonies of Pseudomonas. About 100 colonies were chosen and subjected to biochemical tests for confirmation of their identity. Eighteen strains of the Pseudomonas genus were identified and submitted to tests for the production of antimicrobial substances. Twelve strains (66.7% were identified as Pseudomonas fluorescens, four (22.2% as P. aeruginosa, one (5.5% as P. mendocina and one (5.5% as P. pseudoalcaligenes. Only two P. fluorescens strains were unable to produce any antimicrobial substance against any of the indicator strains tested. Most of the strains presented a broad spectrum of action, inhibiting reference and food-related strains such as Proteus vulgaris, Proteus mirabilis, Hafnia alvei, Yersinia enterocolitica, Escherichia coli and Salmonella typhi. Five antimicrobial substance-producing strains, which presented the broadest spectrum of action, were also tested against Staphylococcus aureus reference strains and 26 Staphylococcus sp. strains isolated from foods, some of which were resistant to antibiotics. The producer strains 8.1 and 8.3, both P. aeruginosa, were able to inhibit all the staphylococcal strains tested. The antimicrobial substances produced by strains 8.1 and 8.3 did not seem to be typical bacteriocins, since they were resistant to the three proteolytic enzymes tested. Experiments involving the characterization of these substances are being carried out in order to evaluate their biotechnological application.

Molecular Detection of Aflatoxin Producing Strains of Aspergillus Flavus from Peanut (Arachis Hypogaea

Directory of Open Access Journals (Sweden)

Adeela Hussain

2015-02-01

Full Text Available Aflatoxins are the potential carcinogens produced as secondary metabolites by Aspergillus flavus. They have the ability to contaminate large number of food which ultimately affect the human population. Malt extract agar was selected for the growth of control stains of fungus. The aim of the study was to develop a reliable and quick method for the detection of aflatoxin producing strains in peanuts by using molecular approaches. Total 80 samples of infected peanuts were collected from four different cities of Punjab and checked for their aflatoxin contamination. For aflatoxin detection, three target genes nor1, ver1 and aflR were selected which was involved in the aflatoxin biosynthesis. In all examined cases, 24 out of 80 (30% samples successfully amplified all three genes indicating aflatoxigenic activity. Discrimination between aflatoxigenic and non-aflatoxigenic strains were also determined on the basis of amplification of these three target DNA fragments. In this study, it was also demonstrated that only specific strains were able to produce the aflatoxin contamination in peanuts.

An Investigation of Immunogenicity of Chitosan-Based Botulinum Neurotoxin E Binding Domain Recombinant Candidate Vaccine via Mucosal Route

Directory of Open Access Journals (Sweden)

Mohammad Javad Bagheripour

2017-01-01

Full Text Available Background and Objectives: Botulism syndrome is caused by serotypes A-G of neurotoxins of Clostridium genus. Neurotoxin binding domain is an appropriate vaccine candidate due to its immunogenic activity. In this study, the immunogenicity of chitosan-based botulinum neurotoxin E binding domain recombinant candidate vaccine was investigated via mucosal route of administration. Methods: In this experimental study, chitosan nanoparticles containing rBoNT/E protein were synthesized by ionic gelation method and were administered orally and intranasally to mice. After each administration, IgG antibody titer was measured by ELISA method. Finally, all groups were challenged with active botulinum neurotoxin type E. Data were analyzed using Duncan and repeated ANOVA tests. The significance level was considered as p0.05, even intranasal route reduced the immunogenicity.

Peptide inhibitors of botulinum neurotoxin by mRNA display

International Nuclear Information System (INIS)

Yiadom, Kwabena P.A.B.; Muhie, Seid; Yang, David C.H.

2005-01-01

Botulinum neurotoxins (BoNTs) are extremely toxic. The metalloproteases associated with the toxins cleave proteins essential for neurotransmitter secretion. Inhibitors of the metalloprotease are currently sought to control the toxicity of BoNTs. Toward that goal, we produced a synthetic cDNA for the expression and purification of the metalloprotease of BoNT/A in Escherichia coli as a biotin-ubiquitin fusion protein, and constructed a combinatorial peptide library to screen for BoNT/A light chain inhibitors using mRNA display. A protease assay was developed using immobilized intact SNAP-25 as the substrate. The new peptide inhibitors showed a 10-fold increase in affinity to BoNT/A light chain than the parent peptide. Interestingly, the sequences of the new peptide inhibitors showed abundant hydrophobic residues but few hydrophilic residues. The results suggest that mRNA display may provide a general approach in developing peptide inhibitors of BoNTs

In vitro evaluation of immunological properties of extracellular polysaccharides produced by Lactobacillus delbrueckii strains.

Science.gov (United States)

Kishimoto, Mana; Nomoto, Ryohei; Osawa, Ro

2015-01-01

We investigated the variation in immunological properties of the extracellular polysaccharides (EPSs) produced by different Lactobacillus delbrueckii strains as well as that of their monosaccharide composition. The monosaccharide composition of each EPS produced by L. delbrueckii strains, as determined by thin layer chromatography (TLC), showed an appreciable variation in a strain-dependent manner, which could be broadly assigned to 4 TLC groups. Meanwhile, the immunological properties of the EPSs produced by 10 L. delbrueckii strains were evaluated in a semi-intestinal model using a Transwell co-culture system, which employed human intestinal epithelial Caco-2 cells on the apical side and murine macrophage RAW264.7 cells on the basolateral side. Each EPS was added to the apical side to allow direct contact with Caco-2 cells and incubated for 6 hr. After incubation, the amounts of TNF-α and several cytokines that had been released by either RAW264.7 or Caco-2 cells were then quantified by cytotoxic activity on L929 cells or the RT-PCR method. It was found that the EPS-stimulated RAW264.7 cells express different profiles of cytokine production via Caco-2 cells but that the profile difference could not be related to the above TLC grouping. The evidence suggests that the EPSs of L. delbrueckii strains are diverse not only in their biochemical structure but also in their immunological properties.

CHARACTERIZATION OF A NEW BACILLUS-STEAROTHERMOPHILUS ISOLATE - A HIGHLY THERMOSTABLE ALPHA-AMYLASE-PRODUCING STRAIN

NARCIS (Netherlands)

WIND, RD; BUITELAAR, RM; EGGINK, G; HUIZING, HJ; DIJKHUIZEN, L

A novel strain of Bacillus stearothermophilus was isolated from samples of a potato-processing industry. Compared to known alpha-amylases from other B. stearothermophilus strains, the isolate was found to produce a highly thermostable alpha-amylase. The half-time of inactivation of this

Purification and characterization of a novel subtype a3 botulinum neurotoxin.

Science.gov (United States)

Tepp, William H; Lin, Guangyun; Johnson, Eric A

2012-05-01

Botulinum neurotoxins (BoNTs) produced by Clostridium botulinum are of considerable importance due to their being the cause of human and animal botulism, their potential as bioterrorism agents, and their utility as important pharmaceuticals. Type A is prominent due to its high toxicity and long duration of action. Five subtypes of type A BoNT are currently recognized; BoNT/A1, -/A2, and -/A5 have been purified, and their properties have been studied. BoNT/A3 is intriguing because it is not effectively neutralized by polyclonal anti-BoNT/A1 antibodies, and thus, it may potentially replace BoNT/A1 for patients who have become refractive to treatment with BoNT/A1 due to antibody formation or other modes of resistance. Purification of BoNT/A3 has been challenging because of its low levels of production in culture and the need for innovative purification procedures. In this study, modified Mueller-Miller medium was used in place of traditional toxin production medium (TPM) to culture C. botulinum A3 (CDC strain) and boost toxin production. BoNT/A3 titers were at least 10-fold higher than those produced in TPM. A purification method was developed to obtain greater than 95% pure BoNT/A3. The specific toxicity of BoNT/A3 as determined by mouse bioassay was 5.8 × 10(7) 50% lethal doses (LD(50))/mg. Neutralization of BoNT/A3 toxicity by a polyclonal anti-BoNT/A1 antibody was approximately 10-fold less than the neutralization of BoNT/A1 toxicity. In addition, differences in symptoms were observed between mice that were injected with BoNT/A3 and those that were injected with BoNT/A1. These results indicate that BoNT/A3 has novel biochemical and pharmacological properties compared to those of other subtype A toxins.

Morphological characterization of recombinant strains of Aspergillus oryzae producing alpha-amylase during batch cultivations

DEFF Research Database (Denmark)

Spohr, Anders Bendsen; Carlsen, Morten; Nielsen, Jens Bredal

1997-01-01

Three alpha-amylase producing strains of Aspergillus oryzae used for recombinant protein production have been studied with respect to growth and protein production. By comparing the three strains with respect to morphology and protein production it is shown that a morphological mutant with a more...

Design of homo-organic acid producing strains using multi-objective optimization

DEFF Research Database (Denmark)

Kim, Tae Yong; Park, Jong Myoung; Kim, Hyun Uk

2015-01-01

Production of homo-organic acids without byproducts is an important challenge in bioprocess engineering to minimize operation cost for separation processes. In this study, we used multi-objective optimization to design Escherichia coli strains with the goals of maximally producing target organic ...

Structure-Function Relationship of Hydrophiidae Postsynaptic Neurotoxins

Science.gov (United States)

1992-03-11

Fulde, G. (1987) Clin. Dermatology 5: 118. Tu, A. T. (1985) Detection of the sulfhydryl group in proteins by raman scattering spectroscopic method. J...properties of novel forms lacking tryptophan. J. Biochem. 85: 379-388. Yu, N. T., Lin, T. S., and Tu, A. T. (1975) Laser Raman scattering uf neurotoxins...hardwickii), binds tightly and specifically to the nicotinic acetylcholine receptor (AChR) inhibiting neumuscular transmission and results in muscular

Isolation and Identification of L-asparaginase producing Erwinia strains which isolated from Potato Farms

Directory of Open Access Journals (Sweden)

Arastoo Badoei-Dalfard

2016-09-01

Full Text Available Introduction: L-Asparaginase can be effectively used for the treatment of lymphoblastic leukemia. The rapid growth of cancer cells are needed for L-asparagine abundant storage. L-asparaginase catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. The purpose of this study was to isolate and identify the L-asparaginase producing Erwinia strains from the potato farms of Jiroft. Materials and methods: Pectolytic Erwinia species isolated from crumbling potato in M9 medium. The desired L-asparaginase producing bacteria were isolated based on the color changes. Biochemical-microbial and the plant pathogenicity tests of these strains were also investigated with potato and geranium. The L-asparaginase production and molecular detection of these Erwinia strains were also investigated. Results: In this study, L-asparaginase producing Erwinia was isolated on the CVP and M9 mediums. The inoculation of Erwinia strains on the potato and geranium plants showed that Er8 and Er11 species have the ability to cause plant pathogenicity. Results showed that the maximum pathogenicity of Er8 and Er11 was observed after 48 and 15 h of inoculation in potato and geranium plants, respectively. 16S rDNA sequencing and phylogenetic analyses exhibited that Er8 and Er11 strains were similar to Erwinia chrysanthemi with 98% homology. Discussion and conclusion: Because of several applications of the Erwinia L-asparaginase in various fields, isolated Erwinia and their L-asparaginase can be suitable for applied utilization.

Metabolic engineering of a haploid strain derived from a triploid industrial yeast for producing cellulosic ethanol.

Science.gov (United States)

Kim, Soo Rin; Skerker, Jeffrey M; Kong, In Iok; Kim, Heejin; Maurer, Matthew J; Zhang, Guo-Chang; Peng, Dairong; Wei, Na; Arkin, Adam P; Jin, Yong-Su

2017-03-01

Many desired phenotypes for producing cellulosic biofuels are often observed in industrial Saccharomyces cerevisiae strains. However, many industrial yeast strains are polyploid and have low spore viability, making it difficult to use these strains for metabolic engineering applications. We selected the polyploid industrial strain S. cerevisiae ATCC 4124 exhibiting rapid glucose fermentation capability, high ethanol productivity, strong heat and inhibitor tolerance in order to construct an optimal yeast strain for producing cellulosic ethanol. Here, we focused on developing a general approach and high-throughput screening method to isolate stable haploid segregants derived from a polyploid parent, such as triploid ATCC 4124 with a poor spore viability. Specifically, we deleted the HO genes, performed random sporulation, and screened the resulting segregants based on growth rate, mating type, and ploidy. Only one stable haploid derivative (4124-S60) was isolated, while 14 other segregants with a stable mating type were aneuploid. The 4124-S60 strain inherited only a subset of desirable traits present in the parent strain, same as other aneuploids, suggesting that glucose fermentation and specific ethanol productivity are likely to be genetically complex traits and/or they might depend on ploidy. Nonetheless, the 4124-60 strain did inherit the ability to tolerate fermentation inhibitors. When additional genetic perturbations known to improve xylose fermentation were introduced into the 4124-60 strain, the resulting engineered strain (IIK1) was able to ferment a Miscanthus hydrolysate better than a previously engineered laboratory strain (SR8), built by making the same genetic changes. However, the IIK1 strain showed higher glycerol and xylitol yields than the SR8 strain. In order to decrease glycerol and xylitol production, an NADH-dependent acetate reduction pathway was introduced into the IIK1 strain. By consuming 2.4g/L of acetate, the resulting strain (IIK1A

Effects of some organic pollutants on the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains

International Nuclear Information System (INIS)

Onbasli, Dilsad; Aslim, Belma

2009-01-01

In this study, isolation and characterization of exopolysaccharides produced by Pseudomonas aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 which had been seen to produce exopolymers of potential interest in biotechnological applications were examined. To initiate the observation of the organic pollutants-polymer interactions, the yield and properties of their extracellular polysaccharide were researched. The exopolysaccharide production by these strains during growth in nutrient broth medium (control) was 41-75 mg L -1 . Also, P. aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 had exhibited high production of EPSs in presence of various organic pollutants (2,4-D, benzene, BTX and gasoline, respectively) in mineral salt medium (MSM) as a sole carbon source. EPS production by the 4 strains ranged from 40 mg L -1 to 8 mg L -1 . Monosaccharide composition of EPS produced by these cultures were analyzed by HPLC. Results indicated that EPSs of strains contained neutral sugars and acetylated amino sugars. The neutral sugars in the EPS were mainly composed of glucose, arabinose, glycerol, ribose. The presence of galactronic acid, N-acetyl-D-galactosamin and N-acetyl-D-glucosamine indicated the acidic nature of the polysaccharide. Glycerol was the basic structural unit of EPS produced by the strains except P. stutzeri B11 (MSM with 1% BTX). Strain B1 (in NB medium) was found to be composed of neutral sugars (100%) while strain B1 [in MSM medium with 0.2% (v/v) 2.4-D] contained neutral sugars (70.0%), acetylated amino sugars (30.0%). Also, EPS content of strain B5 (in the NB medium) was neutral sugars (99.8%), acetylated amino sugars (0.2%) while the strain B5 [in MSM medium containing the 1% (v/v) benzene] was found to contain neutral sugars (99.9%), acetylated amino sugars (0.1%). However, EPS monomer composition by strain B11 was detected as neutral sugars (99.77%), acetylated amino sugars (0.23%) in NB medium while the strain B11

Proteome response of Tribolium castaneum larvae to Bacillus thuringiensis toxin producing strains.

Directory of Open Access Journals (Sweden)

Estefanía Contreras

Full Text Available Susceptibility of Tribolium castaneum (Tc larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific Bacillus thuringiensis Cry toxin producing strains and those containing the structurally unrelated Cry3Ba and Cry23Aa/Cry37Aa proteins were found toxic (LC(50 values 13.53 and 6.30 µg spore-crystal mixture/µL flour disc, respectively. Using iTRAQ combined with LC-MS/MS allowed the discovery of seven novel differentially expressed proteins in early response of Tc larvae to the two active spore-crystal mixtures. Proteins showing a statistically significant change in treated larvae compared to non-intoxicated larvae fell into two major categories; up-regulated proteins were involved in host defense (odorant binding protein C12, apolipophorin-III and chemosensory protein 18 and down-regulated proteins were linked to metabolic pathways affecting larval metabolism and development (pyruvate dehydrogenase Eα subunit, cuticular protein, ribosomal protein L13a and apolipoprotein LI-II. Among increased proteins, Odorant binding protein C12 showed the highest change, 4-fold increase in both toxin treatments. The protein displayed amino acid sequence and structural homology to Tenebrio molitor 12 kDa hemolymph protein b precursor, a non-olfactory odorant binding protein. Analysis of mRNA expression and mortality assays in Odorant binding protein C12 silenced larvae were consistent with a general immune defense function of non-olfactory odorant binding proteins. Regarding down-regulated proteins, at the transcriptional level, pyruvate dehydrogenase and cuticular genes were decreased in Tc larvae exposed to the Cry3Ba producing strain compared to the Cry23Aa/Cry37Aa producing strain, which may contribute to the developmental arrest that we observed with larvae fed the Cry3Ba producing strain. Results demonstrated a distinct host transcriptional regulation depending upon the Cry toxin treatment. Knowledge

Efficacy of a potential trivalent vaccine based on Hc fragments of botulinum toxins A, B, and E produced in a cell-free expression system.

Science.gov (United States)

Zichel, R; Mimran, A; Keren, A; Barnea, A; Steinberger-Levy, I; Marcus, D; Turgeman, A; Reuveny, S

2010-05-01

Botulinum toxins produced by the anaerobic bacterium Clostridium botulinum are the most potent biological toxins in nature. Traditionally, people at risk are immunized with a formaldehyde-inactivated toxin complex. Second generation vaccines are based on the recombinant carboxy-terminal heavy-chain (Hc) fragment of the neurotoxin. However, the materialization of this approach is challenging, mainly due to the high AT content of clostridial genes. Herein, we present an alternative strategy in which the native genes encoding Hc proteins of botulinum toxins A, B, and E were used to express the recombinant Hc fragments in a cell-free expression system. We used the unique property of this open system to introduce different combinations of chaperone systems, protein disulfide isomerase (PDI), and reducing/oxidizing environments directly to the expression reaction. Optimized expression conditions led to increased production of soluble Hc protein, which was successfully scaled up using a continuous exchange (CE) cell-free system. Hc proteins were produced at a concentration of more than 1 mg/ml and purified by one-step Ni(+) affinity chromatography. Mice immunized with three injections containing 5 microg of any of the in vitro-expressed, alum-absorbed, Hc vaccines generated a serum enzyme-linked immunosorbent assay (ELISA) titer of 10(5) against the native toxin complex, which enabled protection against a high-dose toxin challenge (10(3) to 10(6) mouse 50% lethal dose [MsLD(50)]). Finally, immunization with a trivalent HcA, HcB, and HcE vaccine protected mice against the corresponding trivalent 10(5) MsLD(50) toxin challenge. Our results together with the latest developments in scalability of the in vitro protein expression systems offer alternative routes for the preparation of botulinum vaccine.

Draft Genome Sequence of the Efficient Bioflocculant-Producing Bacterium Paenibacillus sp. Strain A9

Science.gov (United States)

Liu, Jin-liang; Hu, Xiao-min

2013-01-01

Paenibacillus sp. strain A9 is an important bioflocculant-producing bacterium, isolated from a soil sample, and is pale pink-pigmented, aerobic, and Gram-positive. Here, we report the draft genome sequence and the initial findings from a preliminary analysis of strain A9, which is a novel species of Paenibacillus. PMID:23618713

Prediction of antigenic epitopes and MHC binders of neurotoxin ...

African Journals Online (AJOL)

PRECIOUS

2009-12-01

Dec 1, 2009 ... scorpion chlorotoxin-like short-chain neurotoxins (SCNs). *Corresponding ... Protein sequence analysis. Here we ... MHC/peptide binding is a log-transformed value related to the IC50 values in nM ..... porter. Adducts of MHC and peptide complexes are the ligands for T cell receptors (TCR) (Table-1). MHC.

Biochemistry of snake venom neurotoxins and their application to the study of synapse. [Neurotoxins isolated from venom of the Formosan banded krait

Energy Technology Data Exchange (ETDEWEB)

Hanley, M.R.

1978-11-01

The crude venom of the Formosan banded krait, Bungarus multicinctus, was separated into eleven lethal protein fractions. Nine fractions were purified to final homogeneous toxins, designated ..cap alpha..-bungarotoxin, ..beta..-bungarotoxin, and toxins 7, 8, 9A, 11, 12, 13, and 14. Three of the toxins, ..cap alpha..-bungarotoxin, 7, and 8, were identified as post-synaptic curarimimetic neurotoxins. The remaining toxins were identified as pre-synaptic neurotoxins. ..cap alpha..-Bungarotoxin, toxin 7, and toxin 8 are all highly stable basic polypeptides of approx. 8000 daltons molecular weight. The pre-synaptic toxins fell into two structural groups: toxin 9A and 14 which were single basic chains of approx. 14,000 daltons, and ..beta..-bungarotoxin, and toxins 11 thru 13 which were composed of two chains of approx. 8000 and approx. 13,000 daltons covalently linked by disulfides. All the pre-synaptic neurotoxins were shown to have intrinsic calcium-dependent phospholipase A activities. Under certain conditions, intact synaptic membranes were hydrolyzed more rapidly than protein-free extracted synaptic-lipid liposomes which, in turn, were hydrolyzed more rapidly than any other tested liposomes. It was speculated that cell-surface arrays of phosphatidyl serine/glycolipids created high affinity target sites for ..beta..-bungarotoxin. Single-chain toxins were found to be qualitatively different from the two-chain toxins in their ability to block the functioning of acetylcholine receptors, and were quantitatively different in their enzymatic and membrane disruptive activities. ..beta..-Bungarotoxin was shown to be an extremely potent neuronal lesioning agent. There was no apparent selectivity for cholinergic over non-cholinergic neurons, nor for nerve terminals over cell bodies. It was suggested that ..beta..-bungarotoxin can be considered a useful new histological tool, which may exhibit some regional selectivity.

Alpha toxin specific PCR for detection of toxigenic strains of Clostridium perfringens in Poultry

Directory of Open Access Journals (Sweden)

Malmarugan Shanmugasamy

2012-12-01

Full Text Available Aim : Isolation of clostridium perfirngens from necrotic enteritis cases in poultry and confirmation by alpha toxin specific PCR Materials and methods: Robertson cooked meat medium with Brain Heart Infusion broth was used for isolation of C. perfringens from intestinal contents of necrotic enteritis suspected birds. Positive cultures from perfringens agar were further confirmed by biochemical tests and subjected to alpha toxin specific PCR. Results: Twenty Clostridium perfringens isolates were isolated from intestinal contents of thirty five NE suspected birds. Out of the twenty isolates, fourteen were isolated from commercial broilers of 2 to 6 wk of age and six from commercial layers of 9 to 15 wk of age. Frequency of isolation of C. perfringens was more with Robertson cooked meat medium with BHI broth than thioglycollate broth alone. When positive cultures were streaked on to clostridial agar appreciable luxuriant growths were obtained and the selective streaking of these colonies on perfringens agar with supplements revealed rough and black colonies with sulphate reduction. The isolates produced rough and black colonies with sulphate reduction on perfringens agar, double zone haemolysis on sheep blood agar, stormy clot fermentation on milk medium and opalescence on egg yolk medium. The isolates were found negative for oxidase, catalase, liquefied gelatin, fermented glucose, maltose, lactose and sucrose except mannitol. All the fourteen isolates obtained from commercial broilers proved the alpha toxin producing strains of C. perfringens when they were subjected to alpha toxin specific PCR. Conclusion : This study revealed alpha toxin specific PCR is highly useful for detection of toxigenic strains of Clostridium perfringens in poultry [Vet. World 2012; 5(6.000: 365-368

Nesterenkonia sp. strain F, a halophilic bacterium producing acetone, butanol, and ethanol under aerobic conditions.

Science.gov (United States)

Amiri, Hamid; Azarbaijani, Reza; Parsa Yeganeh, Laleh; Shahzadeh Fazeli, Abolhassan; Tabatabaei, Meisam; Salekdeh, Ghasem Hosseini; Karimi, Keikhosro

2016-01-04

The moderately halophilic bacterium Nesterenkonia sp. strain F, which was isolated from Aran-Bidgol Lake (Iran), has the ability to produce acetone, butanol, and ethanol (ABE) as well as acetic and butyric acids under aerobic and anaerobic conditions. This result is the first report of ABE production with a wild microorganism from a family other than Clostridia and also the first halophilic species shown to produce butanol under aerobic cultivation. The cultivation of Nesterenkonia sp. strain F under anaerobic conditions with 50 g/l of glucose for 72 h resulted in the production of 105 mg/l of butanol, 122 mg/l of acetone, 0.2 g/l of acetic acid, and 2.5 g/l of butyric acid. Furthermore, the strain was cultivated on media with different glucose concentrations (20, 50, and 80 g/l) under aerobic and anaerobic conditions. Through fermentation with a 50 g/l initial glucose concentration under aerobic conditions, 66 mg/l of butanol, 125 mg/l of acetone, 291 mg/l of ethanol, 5.9 g/l of acetic acid, and 1.2 g/l of butyric acid were produced. The enzymes pertaining to the fermentation pathway in the strain were compared with the enzymes of Clostridium spp., and the metabolic pathway of fermentation used by Nesterenkonia sp. strain F was investigated.

Protective vaccination with a recombinant fragment of Clostridium botulinum neurotoxin serotype A expressed from a synthetic gene in Escherichia coli.

OpenAIRE

Clayton, M A; Clayton, J M; Brown, D R; Middlebrook, J L

1995-01-01

A completely synthetic gene encoding fragment C, a approximately 50-kDa fragment, of botulinum neurotoxin serotype A was constructed from oligonucleotides. The gene was expressed in Escherichia coli, and full-sized product was produced as judged by Western blot (immunoblot) analysis. Crude extracts of E. coli expressing the gene were used to vaccinate mice and evaluate their survival against challenge with active toxin. Mice given three subcutaneous vaccinations were protected against an intr...

Clonality and Resistome analysis of KPC-producing Klebsiella pneumoniae strain isolated in Korea using whole genome sequencing.

Science.gov (United States)

Lee, Yangsoon; Kim, Bong-Soo; Chun, Jongsik; Yong, Ji Hyun; Lee, Yeong Seon; Yoo, Jung Sik; Yong, Dongeun; Hong, Seong Geun; D'Souza, Roshan; Thomson, Kenneth S; Lee, Kyungwon; Chong, Yunsop

2014-01-01

We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC-) producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR) K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including bla KPC-2, bla SHV-11, bla TEM-169, and bla OXA-9. MP14 also possessed aac(6'-)Ib, aadA2, and aph(3'-)Ia as aminoglycoside resistance-encoding genes, mph(A) for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains) isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

Clonality and Resistome Analysis of KPC-Producing Klebsiella pneumoniae Strain Isolated in Korea Using Whole Genome Sequencing

Directory of Open Access Journals (Sweden)

Yangsoon Lee

2014-01-01

Full Text Available We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC- producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including blaKPC-2, blaSHV-11, blaTEM-169, and blaOXA-9. MP14 also possessed aac(6′-Ib, aadA2, and aph(3′-Ia as aminoglycoside resistance-encoding genes, mph(A for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

Detection and transmission of extracellular fac-tor producing Streptococcus suis serotype 2 strains in pigs

NARCIS (Netherlands)

Swildens, B.

2009-01-01

DETECTION AND TRANSMISSION OF EXTRACELLULAR FACTOR PRODUCING STREPTOCOCCUS SUIS SEROTYPE 2 STRAINS IN PIGS INTRODUCTION Streptococcus suis (S.suis) has been implicated in the etiology of many diseases among which meningitis in pigs. The virulent extracellular factor-positive strains of S.suis

Lactobacillus plantarum CIDCA 8327: An α-glucan producing-strain isolated from kefir grains.

Science.gov (United States)

Gangoiti, M V; Puertas, A I; Hamet, M F; Peruzzo, P J; Llamas, M G; Medrano, M; Prieto, A; Dueñas, M T; Abraham, A G

2017-08-15

Lactobacillus plantarum CIDCA 8327 is an exopolysaccharide (EPS)-producer strain isolated from kefir with promising properties for the development of functional foods. The aim of the present study was to characterize the structure of the EPS synthesized by this strain grown in skim milk or semidefined medium (SDM). Additionally, genes involved in EPS synthesis were detected by PCR. L. plantarum produces an EPS with a molecular weight of 10 4 Da in both media. When grown in SDM produce an heteropolysaccharide composed mainly of glucose, glucosamine and rhamnose meanwhile the EPS produced in milk was composed exclusively of glucose indicating the influence of the sugar source. FTIR spectra of this EPS showed signals attributable to an α-glucan. Both by 1 H NMR and methylation analysis it was possible to determine that this polysaccharide is a branched α-(1→4)-d-glucan composed of 80% linear α-(1→4)-d-glucopyranosyl units and 19% (1→4)-d-glucopyranosyl units substituted at O-3 by single α-d-glucopyranosil residues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis

Directory of Open Access Journals (Sweden)

Carmel M. Barber

2016-02-01

Full Text Available Taipans (Oxyuranus spp. are elapids with highly potent venoms containing presynaptic (β and postsynaptic (α neurotoxins. O. temporalis (Western Desert taipan, a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da, a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM. α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87% with other taipan short-chain postsynaptic neurotoxins.

The prevalence of ESBL-producing E-coli and Klebsiella strains in the Copenhagen area of Denmark

DEFF Research Database (Denmark)

Kjerulf, A.; Hansen, D.S.; Sandvang, D.

2008-01-01

The main purpose of the study was to investigate the frequency of ESBL-producing E. coli and Klebsiella strains in the Greater Copenhagen area. Four collections of strains were investigated: A) 380 consecutive E. coli and Klebsiella isolates primarily from urine, B) 200 gentamicin-resistant E. coli...... and Klebsiella isolates primarily from urine, C) 210 consecutive E. coli isolates from blood cultures, and D) 68 cefuroxime-resistant E. coli and Klebsiella isolates primarily from urine. Only one strain per patient was included. Strains with a zone diameter for cefpodoxime ...). In conclusion, the frequency of ESBL-producing E. coli and Klebsiella isolates was low in the Copenhagen area of Denmark (0.8 %). The most common ESBL genes found in our study were ctx-m and shv genes Udgivelsesdato: 2008/2...

Improved soluble expression and characterization of the Hc domain of Clostridium botulinum neurotoxin serotype A in Escherichia coli by using a PCR-synthesized gene and a Trx co-expression strain.

Science.gov (United States)

Chen, Rongchang; Shi, Jing; Cai, Kun; Tu, Wei; Hou, Xiaojun; Liu, Hao; Xiao, Le; Wang, Qin; Tang, Yunming; Wang, Hui

2010-05-01

Botulinum neurotoxin serotype A (BoNT/A) is an extremely potent bacterial protein toxin. The Hc fragment of BoNT/A (AHc) was shown to be non-toxic, antigenic, and capable of eliciting a protective immunity in animals challenged with homologous BoNT. In this study, we synthesized AHc gene by using T4 DNA ligase and PCR. The AHc was expressed at a high level in Escherichia coli successfully. Because of using the Trx co-expression strain, the expressed AHc is in a soluble and active form. The yield of the purified AHc was about 70mg/L, and its purity was up to 90% through one-step affinity chromatography. The AHc was positively identified by the antibodies raised against BoNT/A using immunological-dot-blot and Western blot assays. AHc was shown to bind with gangliosides and elicit immunity against BoNT/A, indicating that the expressed and purified AHc protein retains a functionally active conformation. Furthermore, the purified AHc has a strong immunogenicity and can be used as a potential subunit candidate vaccine for botulinum toxin serotype A. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Identification, purification and characterization of laterosporulin, a novel bacteriocin produced by Brevibacillus sp. strain GI-9.

Directory of Open Access Journals (Sweden)

Pradip Kumar Singh

Full Text Available BACKGROUND: Bacteriocins are antimicrobial peptides that are produced by bacteria as a defense mechanism in complex environments. Identification and characterization of novel bacteriocins in novel strains of bacteria is one of the important fields in bacteriology. METHODOLOGY/FINDINGS: The strain GI-9 was identified as Brevibacillus sp. by 16 S rRNA gene sequence analysis. The bacteriocin produced by strain GI-9, namely, laterosporulin was purified from supernatant of the culture grown under optimal conditions using hydrophobic interaction chromatography and reverse-phase HPLC. The bacteriocin was active against a wide range of Gram-positive and Gram-negative bacteria. MALDI-TOF experiments determined the precise molecular mass of the peptide to be of 5.6 kDa and N-terminal sequencing of the thermo-stable peptide revealed low similarity with existing antimicrobial peptides. The putative open reading frame (ORF encoding laterosporulin and its surrounding genomic region was fished out from the draft genome sequence of GI-9. Sequence analysis of the putative bacteriocin gene did not show significant similarity to any reported bacteriocin producing genes in database. CONCLUSIONS: We have identified a bacteriocin producing strain GI-9, belonging to the genus Brevibacillus sp. Biochemical and genomic characterization of laterosporulin suggests it as a novel bacteriocin with broad spectrum antibacterial activity.

Identification, purification and characterization of laterosporulin, a novel bacteriocin produced by Brevibacillus sp. strain GI-9.

Science.gov (United States)

Singh, Pradip Kumar; Chittpurna; Ashish; Sharma, Vikas; Patil, Prabhu B; Korpole, Suresh

2012-01-01

Bacteriocins are antimicrobial peptides that are produced by bacteria as a defense mechanism in complex environments. Identification and characterization of novel bacteriocins in novel strains of bacteria is one of the important fields in bacteriology. The strain GI-9 was identified as Brevibacillus sp. by 16 S rRNA gene sequence analysis. The bacteriocin produced by strain GI-9, namely, laterosporulin was purified from supernatant of the culture grown under optimal conditions using hydrophobic interaction chromatography and reverse-phase HPLC. The bacteriocin was active against a wide range of Gram-positive and Gram-negative bacteria. MALDI-TOF experiments determined the precise molecular mass of the peptide to be of 5.6 kDa and N-terminal sequencing of the thermo-stable peptide revealed low similarity with existing antimicrobial peptides. The putative open reading frame (ORF) encoding laterosporulin and its surrounding genomic region was fished out from the draft genome sequence of GI-9. Sequence analysis of the putative bacteriocin gene did not show significant similarity to any reported bacteriocin producing genes in database. We have identified a bacteriocin producing strain GI-9, belonging to the genus Brevibacillus sp. Biochemical and genomic characterization of laterosporulin suggests it as a novel bacteriocin with broad spectrum antibacterial activity.

Selected wild strains of Agaricus bisporus produce high yields of mushrooms at 25°C.

Science.gov (United States)

Navarro, Pilar; Savoie, Jean-Michel

2015-01-01

To cultivate the button mushroom Agaricus bisporus in warm countries or during summer in temperate countries, while saving energy, is a challenge that could be addressed by using the biological diversity of the species. The objective was to evaluate the yield potential of eight wild strains previously selected in small scale experiments for their ability to produce mature fruiting bodies at 25°C and above. Culture units of 8 kg of compost were used. The yield expressed as weight or number per surface unit and earliness of fruiting were recorded during cultivation in climatic rooms at 17, 25 or 30°C. Only strains of A. bisporus var. burnettii were able to fruit at 30°C. At 25°C they produced the highest yields (27 kg m(-2)) and had best earliness. The yields at 25°C for the strains of A. bisporus var. bisporus ranged from 12 to 16 kg m(-2). The yield ratios 25°C/17°C ranged from 0.8 to 1.2. The variety burnettii originated in the Sonoran Desert in California showed adaptation for quickly producing fruiting bodies at high temperature when humidity conditions were favorable. Strains of the variety bisporus showed interesting potentials for their ability to produce mature fruiting bodies at higher temperature than present cultivars and might be used in breeding programs. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Construction and evaluation of an exopolysaccharide-producing engineered bacterial strain by protoplast fusion for microbial enhanced oil recovery.

Science.gov (United States)

Sun, Shanshan; Luo, Yijing; Cao, Siyuan; Li, Wenhong; Zhang, Zhongzhi; Jiang, Lingxi; Dong, Hanping; Yu, Li; Wu, Wei-Min

2013-09-01

Enterobacter cloacae strain JD, which produces water-insoluble biopolymers at optimal temperature of 30°C, and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at high temperatures by protoplast fusion. The obtained fusant strain ZR3 produced exopolysaccharides at up to 45°C with optimal growth temperature at 35°C. The fusant produced exopolysaccharides of approximately 7.5 g/L or more at pH between 7.0 and 9.0. The feasibility of the enhancement of crude oil recovery with the fusant was tested in a sand-packed column at 40°C. The results demonstrated that bioaugmentation of the fusant was promising approach for MEOR. Mass growth of the fusant was confirmed in fermentor tests. Copyright © 2013 Elsevier Ltd. All rights reserved.

Defining the neurotoxin derived illness chronic ciguatera using markers of chronic systemic inflammatory disturbances: a case/control study.

Science.gov (United States)

Shoemaker, Ritchie C; House, Dennis; Ryan, James C

2010-01-01

Ciguatoxins are extremely potent neurotoxins, produced by tropical marine dinoflagellates, that persistently enter into our food web. Over 100,000 people annually experience acute ciguatera poisoning from consuming toxic fish. Roughly 5% of these victims will develop chronic ciguatera (CC), a widespread, multisymptom, multisystem, chronic illness that can last tens of years. CC is marked by disproportionate disability and non-specific refractory symptoms such as fatigue, cognitive deficits and pain, and is suggestive of other illnesses. Its unknown pathophysiology makes both diagnosis and treatment difficult. We wanted to compare objective parameters of visual contrast sensitivity testing, measures of innate immune response and genetic markers in cases to controls to assess the potential for the presence of persistent inflammatory parameters that are demonstrated in other biotoxin associated illnesses at a single specialty clinic. Using 59 CC cases and 59 controls we present in retrospective review, in all cases, abnormalities in immune responses paralleling the chronic systemic inflammatory response syndrome seen in several other chronic diseases. This study defines a preliminary case definition using medical history, total symptoms, visual contrast sensitivity, HLA DR genotype analysis, reduction of regulatory neuropeptides VIP and MSH, and multiple measures of inflammatory immune response, especially C4a and TGFβ1, thereby providing a basis for identification and targeted therapy. CC provides a model for chronic human illness associated with initiation of inflammatory responses by biologically produced neurotoxins. Copyright © 2010 Elsevier Inc. All rights reserved.

CrdR function in a curdlan-producing Agrobacterium sp. ATCC31749 strain.

Science.gov (United States)

Yu, Xiaoqin; Zhang, Chao; Yang, Liping; Zhao, Lamei; Lin, Chun; Liu, Zhengjie; Mao, Zichao

2015-02-10

Agrobacterium sp. ATCC31749 is an efficient curdlan producer at low pH and under nitrogen starvation. The helix-turn-helix transcriptional regulatory protein (crdR) essential for curdlan production has been analyzed, but whether crdR directly acts to cause expression of the curdlan biosynthesis operon (crdASC) is uncertain. To elucidate the molecular function of crdR in curdlan biosynthesis, we constructed a crdR knockout mutant along with pBQcrdR and pBQNcrdR vectors with crdR expression driven by a T5 promoter and crdR native promoter, respectively. Also, we constructed a pAG with the green fluorescent protein (GFP) gene driven by a curdlan biosynthetic operon promoter (crdP) to measure the effects of crdR expression on curdlan biosynthesis. Compared with wild-type (WT) strain biomass production, the biomass of the crdR knockout mutant was not significantly different in either exponential or stationary phases of growth. Mutant cells were non-capsulated and planktonic and produced significantly less curdlan. WT cells were curdlan-capsulated and aggregated in the stationery phase. pBQcrdR transformed to the WT strain had a 38% greater curdlan yield and pBQcrdR and pBQNcrdR transformed to the crdR mutant strain recovered 18% and 105% curdlan titers of the WT ATCC31749 strain, respectively. Consistent with its function of promoting curdlan biosynthesis, curdlan biosynthetic operon promoter (crdP) controlled GFP expression caused the transgenic strain to have higher GFP relative fluorescence in the WT strain, and no color change was observed with low GFP relative fluorescence in the crdR mutant strain as evidenced by fluorescent microscopy and spectrometric assay. q-RT-PCR revealed that crdR expression in the stationary phase was greater than in the exponential phase, and crdR overexpression in the WT strain increased crdA, crdS, and crdC expression. We also confirmed that purified crdR protein can specifically bind to the crd operon promoter region, and we inferred

Interaction of a dinoflagellate neurotoxin with voltage-activated ion channels in a marine diatom.

Science.gov (United States)

Kitchen, Sheila A; Bourdelais, Andrea J; Taylor, Alison R

2018-01-01

The potent neurotoxins produced by the harmful algal bloom species Karenia brevis are activators of sodium voltage-gated channels (VGC) in animals, resulting in altered channel kinetics and membrane hyperexcitability. Recent biophysical and genomic evidence supports widespread presence of homologous sodium (Na + ) and calcium (Ca 2+ ) permeable VGCs in unicellular algae, including marine phytoplankton. We therefore hypothesized that VGCs of these phytoplankton may be an allelopathic target for waterborne neurotoxins produced by K. brevis blooms that could lead to ion channel dysfunction and disruption of signaling in a similar manner to animal Na + VGCs. We examined the interaction of brevetoxin-3 (PbTx-3), a K. brevis neurotoxin, with the Na + /Ca 2+ VGC of the non-toxic diatom Odontella sinensi s using electrophysiology. Single electrode current- and voltage- clamp recordings from O. sinensis in the presence of PbTx-3 were used to examine the toxin's effect on voltage gated Na + /Ca 2+ currents. In silico analysis was used to identify the putative PbTx binding site in the diatoms. We identified Na + /Ca 2+ VCG homologs from the transcriptomes and genomes of 12 diatoms, including three transcripts from O. sinensis and aligned them with site-5 of Na + VGCs, previously identified as the PbTx binding site in animals. Up to 1 µM PbTx had no effect on diatom resting membrane potential or membrane excitability. The kinetics of fast inward Na + /Ca 2+ currents that underlie diatom action potentials were also unaffected. However, the peak inward current was inhibited by 33%, delayed outward current was inhibited by 25%, and reversal potential of the currents shifted positive, indicating a change in permeability of the underlying channels. Sequence analysis showed a lack of conservation of the PbTx binding site in diatom VGC homologs, many of which share molecular features more similar to single-domain bacterial Na + /Ca 2+ VGCs than the 4-domain eukaryote channels

Clostridium botulinum neurotoxin type B is heat-stable in milk and not inactivated by pasteurization.

Science.gov (United States)

Rasooly, Reuven; Do, Paula M

2010-12-08

Foodborne botulism is caused by the ingestion of foods containing botulinum neurotoxins (BoNTs). To study the heat stability of Clostridium botulinum neurotoxins, we needed to measure and compare the activity of botulinum neurotoxins, serotypes A and B, under various pasteurization conditions. Currently, the only accepted assay to detect active C. botulinum neurotoxin is an in vivo mouse bioassay, which raises ethical concerns with regard to the use of experimental animals. In this study, noninvasive methods were used to simultaneously detect and distinguish between active BoNT serotypes A and B in one reaction and sample. We developed an enzymatic activity assay employing internally quenched fluorogenic peptides corresponding to SNAP-25, for BoNT-A, and VAMP2, for BoNT-B, as an alternative method to the mouse bioassay. Because each peptide is labeled with different fluorophores, we were able to distinguish between these two toxins. We used this method to analyze the heat stability of BoNT-A and BoNT-B. This study reports that conventional milk pasteurization (63 °C, 30 min) inactivated BoNT serotype A; however, serotype B is heat-stable in milk and not inactivated by pasteurization. Using this activity assay, we also showed that the commonly used food processes such as acidity and pasteurization, which are known to inhibit C. botulinum growth and toxin production, are more effective in inactivating BoNT serotype A than serotype B when conventional pasteurization (63 °C, 30 min) is used.

Selection of daunorubicin-producing strain S. Coeruleorubidus by plasma radiation technology

International Nuclear Information System (INIS)

Jiang Shichun; Wu Jianping; Bai Hua

2001-01-01

The authors reported the results of mutagenesis by nitrogen plasma radiation with energy from 65 to 80 keV and dose from 9.6 x 10 9 to 1.5 x 10 11 /cm 2 in antineoplastic antibiotics daunorubicin-producing S. Coeruleorubidus. The relationship between death rate and radiation dose was formulated by computer and the formula. It was fit to a biological single-hit curve. The obtained high-producing mutagenic strain 137 was tested for its production property. The result showed that it could increase the daunorubicin potency by 25.8% in productive tanks of fermentation

Characterization of a novel biosurfactant produced by Staphylococcus sp. strain 1E with potential application on hydrocarbon bioremediation.

Science.gov (United States)

Eddouaouda, Kamel; Mnif, Sami; Badis, Abdelmalek; Younes, Sonia Ben; Cherif, Slim; Ferhat, Samira; Mhiri, Najla; Chamkha, Mohamed; Sayadi, Sami

2012-08-01

A biosurfactant-producing bacterium (Staphylococcus sp. strain 1E) was isolated from an Algerian crude oil contaminated soil. Biosurfactant production was tested with different carbon sources using the surface tension measurement and the oil displacement test. Olive oil produced the highest reduction in surface tension (25.9 dynes cm(-1)). Crude oil presented the best substrate for 1E biosurfactant emulsification activity. The biosurfactant produced by strain 1E reduced the growth medium surface tension below 30 dynes cm(-1). This reduction was also obtained in cell-free filtrates. Biosurfactant produced by strain 1E showed stability in a wide range of pH (from 2 to 12), temperature (from 4 to 55 °C) and salinity (from 0 to 300 g l(-1)) variations. The biosurfactant produced by strain 1E belonged to lipopeptide group and also constituted an antibacterial activity againt the pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. Phenanthrene solubility in water was enhanced by biosurfactant addition. Our results suggest that the 1E biosurfactant has interesting properties for its application in bioremediation of hydrocarbons contaminated sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Examination by Site-Directed Mutagenesis of Putative Key Residues in the Determination of Coenzyme Specificity in Clostridial NAD+-Dependent Glutamate Dehydrogenase

Directory of Open Access Journals (Sweden)

Joanna Griffin

2011-01-01

Full Text Available Sequence and structure comparisons of various glutamate dehydrogenases (GDH and other nicotinamide nucleotide-dependent dehydrogenases have potentially implicated certain residues in coenzyme binding and discrimination. We have mutated key residues in Clostridium symbiosum NAD+-specific GDH to investigate their contribution to specificity and to enhance acceptance of NADPH. Comparisons with E. coli NADPH-dependent GDH prompted design of mutants F238S, P262S, and F238S/P262S, which were purified and assessed at pH 6.0, 7.0, and 8.0. They showed markedly increased catalytic efficiency with NADPH, especially at pH 8.0 (∼170-fold for P262S and F238S/P262S with relatively small changes for NADH. A positive charge introduced through the D263K mutation also greatly increased catalytic efficiency with NADPH (over 100-fold at pH 8 and slightly decreased activity with NADH. At position 242, “P6” of the “core fingerprint,” where NAD+- and NADP+-dependent enzymes normally have Gly or Ala, respectively, clostridial GDH already has Ala. Replacement with Gly produced negligible shift in coenzyme specificity.

Screening of mutant strains producing phytase from A. niger by 60Co γ-ray irradiation

International Nuclear Information System (INIS)

Yang Pingping; Wang Yan; Tao Wenyi

2004-01-01

60 Co γ-ray was used to irradiate Aspergillus niger 447-92 for screening the mutant strain of producing phytase, and the effects of mutation induction were determined and analyzed. A mutant strain A. niger 496-1 with high level of phytase was selected, the phytase properties of A. niger 496-1 were analyzed

Detection and Characterization of Histamine-Producing Strains of Photobacterium damselae subsp. damselae Isolated from Mullets

Directory of Open Access Journals (Sweden)

Marcello Trevisani

2017-06-01

Full Text Available Photobacterium damselae subsp. damselae (Pdd is considered to be an emerging pathogen of marine fish and has also been implicated in cases of histamine food poisoning. In this study, eight strains isolated from mullets of the genera Mugil and Liza captured in the Ligurian Sea were characterized, and a method to detect histamine-producing Pdd from fish samples was developed. The histamine-producing potential of the strains was evaluated in culture media (TSB+ using a histamine biosensor. Subsequently, two strains were used to contaminate mackerel fillets (4 or 40 CFU/g, simulating a cross-contamination on the selling fish stalls. Sample homogenates were enriched in TSB+. The cultures were then inoculated on thiosulfate-citrate-bile salts-sucrose agar (TCBS and the dark green colonies were cultured on Niven agar. The violet isolates were characterized using specific biochemical and PCR based tests. All Pdd strains were histamine producers, yielding concentration varying from 167 and 8977 µg/mL in TSB+ cultures incubated at 30 °C for 24 h. Pdd colonies were detected from the inoculated mackerel samples and their histidine decarboxylase gene was amplified using species-specific primer pairs designed for this study. The results indicate that mullets can be source of Pdd and the fish retailers needs to evaluate the risk posed by cross-contamination on the selling fish stalls.

Isolation, Fermentation Optimization and Performance Studies of a Novel Biosurfactant Producing Strain Bacillus amyloliquefaciens

OpenAIRE

Zhang, W.; Zhang, X.; Cui, H.

2015-01-01

In this research, biosurfactant-producing bacteria were isolated from the outlet sludge of a canteen and one promising strain was identified through 16S rDNA sequence as Bacillus amyloliquefaciens. This strain can utilize water-soluble carbon source and the FT-IR analysis indicated the biosurfactant was probably glycolipids. Further factors (fermentation time, temperature, carbon source, nitrogen source, ion concentration) affecting the biosurfactant production were determined. The optimum fe...

[Mechanism of action of neurotoxins acting on the inactivation of voltage-gated sodium channels].

Science.gov (United States)

Benoit, E

1998-01-01

This review focuses on the mechanism(s) of action of neurotoxins acting on the inactivation of voltage-gated Na channels. Na channels are transmembrane proteins which are fundamental for cellular communication. These proteins form pores in the plasma membrane allowing passive ionic movements to occur. Their opening and closing are controlled by gating systems which depend on both membrane potential and time. Na channels have three functional properties, mainly studied using electrophysiological and biochemical techniques, to ensure their role in the generation and propagation of action potentials: 1) a highly selectivity for Na ions, 2) a rapid opening ("activation"), responsible for the depolarizing phase of the action potential, and 3) a late closing ("inactivation") involved in the repolarizing phase of the action potential. As an essential protein for membrane excitability, the Na channel is the specific target of a number of vegetal and animal toxins which, by binding to the channel, alter its activity by affecting one or more of its properties. At least six toxin receptor sites have been identified on the neuronal Na channel on the basis of binding studies. However, only toxins interacting with four of these sites (sites 2, 3, 5 et 6) produce alterations of channel inactivation. The maximal percentage of Na channels modified by the binding of neurotoxins to sites 2 (batrachotoxin and some alkaloids), 3 (alpha-scorpion and sea anemone toxins), 5 (brevetoxins and ciguatoxins) et 6 (delta-conotoxins) is different according to the site considered. However, in all cases, these channels do not inactivate. Moreover, Na channels modified by toxins which bind to sites 2, 5 and 6 activate at membrane potentials more negative than do unmodified channels. The physiological consequences of Na channel modifications, induced by the binding of neurotoxins to sites 2, 3, 5 and 6, are (i) an inhibition of cellular excitability due to an important membrane depolarization (site

Bacillus amyloliquefaciens SUBSP. plantarum PROBIOTIC STRAINS AS PROTEASE PRODUCERS

Directory of Open Access Journals (Sweden)

E. V. Маtseliukh

2015-04-01

Full Text Available Proteases from probiotic strains of the genus Bacillus, just like the antibiotics, bacteriocins and other hydrolytic enzymes, are one of the main factors that determine their biological activity. The aim of this work was to study the synthesis and biochemical properties of proteases from two strains Bacillus amyloliquefaciens subsp. plantarum UCM B-5139 and UCM B-5140 that included in the probiotic Endosporin. The cultivation of strains was carried out in flasks under rotating for two days. The influence of physico-chemical parameters of the reaction medium on proteolytic activity was studied on partially purified protease preparations. Lytic activity was determined by turbidimetric method. On the second day of cultivation B. amyloliquefaciens subsp. plantarum UCM В-5139 and UCM В-5140 synthesized the metal-dependent peptidase and serine protease, respectively. The optimum conditions of their action were the following: temperature 37–40 °C and pH 6.5–7.0. Isolated proteases are able to lyse the living cells of Staphylococcus aureus and Candida albicans. Thus we demonstrated that B. amyloliquefaciens subsp. plantarum UCM B-5140 and UCM B-5139, included in the probiotic veterinary preparation Endosporin, produced proteolytic enzymes that hydrolyze the native insoluble proteins (elastin, fibrin and collagen. These enzymes belong to the group of neutral metal-dependent and serine proteases. They are active under physiological conditions against gram-positive bacteria and yeasts. The application of these proteases in biotechnology is considered.

Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome

Science.gov (United States)

Michelacci, Valeria; Bondì, Roslen; Gigliucci, Federica; Franz, Eelco; Badouei, Mahdi Askari; Schlager, Sabine; Minelli, Fabio; Tozzoli, Rosangela; Caprioli, Alfredo; Morabito, Stefano

2016-01-01

Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli. PMID:27584691

Screening and identification of lactic acid bacteria strains with high acid-producing from traditional fermented yak yogurt

Directory of Open Access Journals (Sweden)

Chen Xiaoyong

2017-01-01

Full Text Available A total of 57 strains of lactic acid bacteria (LAB were isolated and purified from traditional fermented Yak Yogurt in Hongyuan-Sichuan and Yangbajing-Tibet. The strains with high acid-produced were screened by soluble calcium circle and titratable acidity determination. The five strains, 7-1, 22-1, 28-1, 34-1 and 62-1, possessed the high acid-producing and the value of titratable acidity is 196.2, 191.1, 192.2, 194.8 and 200.2 T respectively. Based on 16S rDNA sequence analysis, 22-1 was identified as Lactococcus lactis subsp. lactis, 28-1 as Lactobacillus casei, 34-1 as Lactobacillus fermentium, 7-1 and 62-1 as Enterococcus durans. This study could provide the evidence for researching fermentation strains to improve yogurt quality.

Isolation and characterization of a biosurfactant producing strain, Brevibacilis brevis HOB1.

Science.gov (United States)

Haddad, Namir I A; Wang, Ji; Mu, Bozhong

2008-12-01

Biosurfactant-producing bacteria were isolated from the production water of an oil field. Isolates were screened for biosurfactant production using surface tension test. The highest reduction of surface tension was achieved with a bacterial strain which was identified by 16S rRNA gene sequencing as Brevibacilis brevis HOB1. It has been investigated using different carbon and nitrogen sources. It showed that the strain was able to grow and reduce the surface tension of the broth to 29 mN/m on commercial sugar and maltose, and to 32 mN/m on glucose after 72 h of growth. The maximum amount of biosurfactant was obtained when nitrate ions were supplied as nitrogen source. Biosurfactant produced by Brevibacilis brevis HOB1 was confirmed as a lipopeptide class of biosurfactant using TLC test and mass spectra. Lipopeptide isoforms were isolated from cell-free supernatants by acid-precipitation followed by one step of chromatographic separation on solid-phase ODS C18 column. The separation was confirmed by HPLC and ESI Q-TOF MS spectroscopy. Comparing the mass data obtained and the mass numbers reported for the lipopeptide complexes from other strains, it can be concluded that the major lipopeptide product of Brevibacilis brevis HOB1 is the surfactin isoform. This lipopeptide showed strong antibacterial and antifungal activity. It is a candidate for the biocontrol of pathogens in agriculture and other industries.

Draft Genome Sequence of the Microbispora sp. Strain ATCC-PTA-5024, Producing the Lantibiotic NAI-107

DEFF Research Database (Denmark)

Sosio, M.; Gallo, G.; Pozzi, R.

2014-01-01

We report the draft genome sequence of Microbispora sp. strain ATCC-PTA-5024, a soil isolate that produces NAI-107, a new lantibiotic with the potential to treat life-threatening infections caused by multidrug-resistant Gram-positive pathogens. The draft genome of strain Microbispora sp. ATCC...

Characterization of Partially Purified Bacteriocin Like Substance (BLIS Produced by Probiotic Lactobacillus Strains

Directory of Open Access Journals (Sweden)

Saeed Ismail Khanian

2014-05-01

Full Text Available Background: There is an increasing interest in search for antimicrobial peptides (bacteriocins and bacteriocin-like compounds produced by lactic acid bacteria (LAB because of their potential to be used as antimicrobial agents for improving the safety of food products. Objectives: The main objective of study was to evaluate the antibacterial potential of locally isolated Lactic Acid bacteria (LAB and determine their bacteriocin producing ability in in-vitro conditions. Materials and Methods: The antibacterial activity of 77 isolated LAB strains was tested against a number of pathogens by well-diffusion method. The isolates demonstrating antimicrobial potential were selected and tested for the production of bacteriocin or bacteriocin like substance. The bacteriocin produced by two of the isolates were partially purified and characterized. Results: The results indicated the neutralized supernatant fluid of two of the isolates identified as L. brevis LB32 and L. pentosus LP05, were active against the growth of Listeria monocytogenes, Salmonella enteritidis, Shigella dysenteriae, Staphylococcus aureus and Streptococcus pneumoniae. Additionally, L. brevis LB32 was able to inhibit the growth of Salmonella typhi and Klebsiella pneumoniae, while, S. pnuemoniae and L. monocytogenes appeared to be the most sensitive strain as apparent by highest zone of inhibition against these pathogens, respectively. The antimicrobial activity in the supernatant fluids of the mentioned strains remained unaffected after treating with enzymes catalase, lipase and lysozyme, while were strongly sensitive to the action of proteolytic enzymes, suggesting the presence of bacteriocin like inhibitory substance (BLIS in the two isolates. The inhibitory substance produced by the two isolates appeared heat resistant and tolerated 100˚C and 121˚C for 55 minutes and 20 minutes, respectively. Partial purification of the concentrated culture supernatant fluids of L. brevis LB32 and L

Characterization of high exopolysaccharide-producing Lactobacillus strains isolated from mustard pickles for potential probiotic applications.

Science.gov (United States)

Huang, Jing-Yao; Kao, Cheng-Yen; Liu, We-Sin; Fang, Tony J

2017-06-01

The aim of this study was to characterize high exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) isolated from mustard pickles in Taiwan for potential probiotic applications. Among 39 collected LAB strains, four most productive EPS-producing strains were selected for further analysis. Comparative analyses of 16S rDNA genes rpoA and pheS sequences demonstrated that these strains were members of Lactobacillus plantarum-group (LPG). NCD 2, NLD 4, SLC 13, and NLD 16 showed survival rates of 95.83% ± 0.49%, 95.07% ± 0.64%, 105.84% ± 0.82%, and 99.65% ± 0.31% under simulated gastrointestinal conditions, respectively. No cytotoxic effects on macrophage RAW 264.7 cells were observed when they were treated with a low dose (1 μg/ml) of stimulants extracted from the tested LAB strains. The production of nitric oxide in RAW 264.7 cells incubated with various LAB stimulants showed a dose-dependent increase. Among the four strains, SLC 13 showed higher inhibitory activity on growth of Enterococcus faecalis (BCRC 12302) and Yersinia enterocolitica (BCRC 10807). NLD 4 showed strong inhibitory activity against Escherichia coli O157:H7 (ATCC 43894) as compared with the other three strains. In summary, our results suggest that Lactobacillus pentosus SLC 13 may be a good candidate for probiotic applications and for development of antibacterial compounds. [Int Microbiol 20(2):75-84 (2017)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Supplementary Material for: In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

KAUST Repository

Motwalli, Olaa Amin

2017-01-01

Abstract Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Results Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis

Characterization of volatile compounds produced by Lactobacillus helveticus strains in a hard cheese model.

Science.gov (United States)

Cuffia, Facundo; Bergamini, Carina V; Wolf, Irma V; Hynes, Erica R; Perotti, María C

2018-01-01

Starter cultures of Lactobacillus helveticus used in hard cooked cheeses play an important role in flavor development. In this work, we studied the capacity of three strains of L. helveticus, two autochthonous (Lh138 and Lh209) and one commercial (LhB02), to grow and to produce volatile compounds in a hard cheese extract. Bacterial counts, pH, profiles of organic acids, carbohydrates, and volatile compounds were analyzed during incubation of extracts for 14 days at 37 ℃. Lactobacilli populations were maintained at 10 6 CFU ml -1 for Lh138, while decreases of approx. 2 log orders were found for LhB02 and Lh209. Both Lh209 and LhB02 slightly increased the acetic acid content whereas mild increase in lactic acid was produced by Lh138. The patterns of volatiles were dependent on the strain which reflect their distinct enzymatic machineries: LhB02 and Lh209 produced a greater diversity of compounds, while Lh138 was the least producer strain. Extracts inoculated with LhB02 and Lh 209 were characterized by ketones, esters, alcohols, aldehydes, and acids, whereas in the extracts with Lh138 the main compounds belonged to aromatic, aldehydes, and ketones groups. Therefore, Lh209 and LhB02 could represent the best cheese starters to improve and intensify the flavor, and even a starter composed by combinations of LhB02 or Lh209 with Lh138 could also be a strategy to diversify cheese flavor.

Genomic mutational analysis of the impact of the classical strain improvement program on β-lactam producing Penicillium chrysogenum

NARCIS (Netherlands)

Salo, Oleksandr V; Ries, Marco; Medema, Marnix H; Lankhorst, Peter P; Vreeken, Rob J; Bovenberg, Roel A L; Driessen, Arnold J M

2015-01-01

BACKGROUND: Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of β-lactams. The high β-lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This

Growth characteristics and enzyme production optimization of lipase Producing Strain

Science.gov (United States)

Zheng, Chaocheng

2018-01-01

55 samples from different regions were selected and screened by Rhodamine B flat transparent circle method to observe lipase producing effect, among which, LHY-1, identified as Serratia sp. has the characteristics of fast growth, high enzyme production and stable ability. The colony of this strain is white, the edge is smooth and tidy, the surface is moist, the cell is straight, rod-shaped, gram negative, 0.1-0.2 μm in diameter and, length 0.3-0.5 μm in length.

Influence of gastrointestinal system conditions on adhesion of exopolysaccharide-producing Lactobacillus delbrueckii subsp. bulgaricus strains to caco-2 cells

Directory of Open Access Journals (Sweden)

Derya Onal Darilmaz

2011-10-01

Full Text Available This study aimed to assess the transit tolerance of potential probiotic dairy Lactobacillus strains in human uppergastrointestinal tract in vitro, and to evaluate the effect of EPS production on the viability and adhesion of these strains. Survival and adhesion of two exopolysaccharide (EPS-producing L. delbrueckii subsp. bulgaricus strains (B3 and B2 and E. coli ATCC11229 were assessed after the exposure of different pH (gastric juice and gastric plus pancreatic juice challenges. In the artificial gastric juice (pH 2, both the viability of the strain B3 and B2 was decreased. Artificial juice treatments significantly reduced the adhesion to caco-2 cells (P< 0.05. High EPS-producing B3 survived better in the adverse gastrointestinal conditions and showed better ability of adhesion to Caco-2 cells when assessed for competition with E. coli ATCC 11229 compared to low EPS-producing B2. This investigation showed that EPS production could be affected or be involved in the viability, adherence and competition of L. delbrueckii subsp. bulgaricus strains and support the potential of B3 strain for development of new probiotic products.

Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients in the Zagreb region

Directory of Open Access Journals (Sweden)

Branka Bedenić,

2010-02-01

Full Text Available Aim To determine the prevalence of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients during a three-year period, to determine their antibiotic susceptibility, investigate the transfer of ESBL genes with cotransfer of resistance and to characterize isolated beta-lactamases. Methods Antimicrobial susceptibility was determined by disk diffusion and broth microdilution methods. The double-disk test was used for ESBL detection. Transfer of resistance was performed by broth mating method and characterization of isolated beta-lactamases by polymerase chain reaction. Results The prevalence of ESBL-producing E. coli was 1.5% and of K. pneumoniae 4.1% with its different distribution according to patients`age and gender. ESBL-producing K. pneumoniae showed high resistance rates to aminoglycosides, cotrimoxazole, nitrofurantoin and quinolones while ESBL-producing E. coli isolates, with exception of high aminoglycoside resistance, showed low resistance rates to other antibiotics. Successful conjugation of ESBL genes was obtained with 25% E. coli and 76.2% K. pneumoniae strains. Comparing to E. coli, K. pneumoniae strains showed higher rates of aminoglycosideand cotrimoxazole resistance cotransfer. Beta-lactamases of investigated strains belonged to TEM, SHV and CTX-M families.Conclusion The existence of multiple-resistant ESBL-producing E. coli and K. pneumoniae strains was confirmed in observed outpatient population. ESBL-producing K. pneumoniae isolates, in contrast toESBL-producing E. coli, showed higher resistance rates to non-beta-lactam antibiotics, probably caused by cotransfer of resistance genes located on the same plasmid as ESBL genes. It is important to monitor the prevalence of such strains and their possible spreading in the outpatient population of the Zagreb region

Genome Sequence of Lactococcus lactis subsp. lactis NCDO 2118, a GABA-Producing Strain

DEFF Research Database (Denmark)

Oliveira, Letícia C; Saraiva, Tessália D L; Soares, Siomar C

2014-01-01

Lactococcus lactis subsp. lactis NCDO 2118 is a nondairy lactic acid bacterium, a xylose fermenter, and a gamma-aminobutyric acid (GABA) producer isolated from frozen peas. Here, we report the complete genome sequence of L. lactis NCDO 2118, a strain with probiotic potential activity....

Inhibiting oral intoxication of botulinum neurotoxin A by carbohydrate receptor mimics

Science.gov (United States)

Botulinum neurotoxins (BoNTs) cause the disease botulism manifested by flaccid paralysis that could be fatal to humans and animals. Oral ingestion of the toxin with contaminated food is one of the most common routes of BoNT intoxication, where BoNT assembles with several auxiliary proteins to surviv...

Isolation and characterization of exopolysaccharide produced by Vibrio harveyi strain VB23.

Science.gov (United States)

Bramhachari, P V; Dubey, S K

2006-11-01

The aim of the study was to isolate and characterize exopolysaccharide (EPS) produced by Vibrio harveyi strain VB23. Growth and EPS production by V. harveyi strain VB23, was studied in mineral salts medium supplemented with NaCl (1.5%) and glucose (0.2%). The rate of EPS production in batch cultures was highest during the late log phase of growth when compared with stationary growth phase. The exopolymer was recovered from the culture supernatant by using a cold ethanol precipitation-dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, proteins and sulfates. The purified EPS revealed prominent functional reactive groups, such as hydroxyl, carboxylic and amides, which correspond to a typical heteropolymeric polysaccharide and the EPS, also possessed good emulsification activity. The gas chromatographic analysis of an alditol acetate-derivatized sample of EPS revealed that it is composed primarily of galactose and glucose. Minor components found were rhamnose, fucose, ribose, arabinose, xylose and mannose. The EPS produced by V. harveyi strain VB23 is a heteropolysaccharide possessing good emulsification activity. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime-like EPS. This is the first report of EPS characterization in luminous V. harveyi bacteria, which describes the isolation and characterization of an EPS expressed by V. harveyi. The results of the study contributes significantly towards an understanding of the chemical composition and applications of the EPS in environmental biotechnology and bioremediation.

Lignocellulose-Adapted Endo-Cellulase Producing Streptomyces Strains for Bioconversion of Cellulose-Based Materials.

Science.gov (United States)

Ventorino, Valeria; Ionata, Elena; Birolo, Leila; Montella, Salvatore; Marcolongo, Loredana; de Chiaro, Addolorata; Espresso, Francesco; Faraco, Vincenza; Pepe, Olimpia

2016-01-01

Twenty-four Actinobacteria strains, isolated from Arundo donax, Eucalyptus camaldulensis and Populus nigra biomass during natural biodegradation and with potential enzymatic activities specific for the degradation of lignocellulosic materials, were identified by a polyphasic approach. All strains belonged to the genus Streptomyces ( S .) and in particular, the most highly represented species was Streptomyces argenteolus representing 50% of strains, while 8 strains were identified as Streptomyces flavogriseus (synonym S. flavovirens ) and Streptomyces fimicarius (synonyms Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies , and Streptomyces flavofuscus ), and the other four strains belonged to the species Streptomyces drozdowiczii, Streptomyces rubrogriseus, Streptomyces albolongus , and Streptomyces ambofaciens . Moreover, all Streptomyces strains, tested for endo and exo-cellulase, cellobiase, xylanase, pectinase, ligninase, peroxidase, and laccase activities using qualitative and semi-quantitative methods on solid growth medium, exhibited multiple enzymatic activities (from three to six). The 24 strains were further screened for endo-cellulase activity in liquid growth medium and the four best endo-cellulase producers ( S. argenteolus AE58P, S. argenteolus AE710A, S. argenteolus AE82P, and S. argenteolus AP51A) were subjected to partial characterization and their enzymatic crude extracts adopted to perform saccharification experiments on A. donax pretreated biomass. The degree of cellulose and xylan hydrolysis was evaluated by determining the kinetics of glucose and xylose release during 72 h incubation at 50°C from the pretreated biomass in the presence of cellulose degrading enzymes (cellulase and β-glucosidase) and xylan related activities (xylanase and β-xylosidase). The experiments were carried out utilizing the endo-cellulase activities from the selected S. argenteolus strains supplemented with commercial β-gucosidase and

Inhibition of the nicotinic acetylcholine receptors by cobra venom α-neurotoxins: is there a perspective in lung cancer treatment?

Directory of Open Access Journals (Sweden)

Angela Alama

Full Text Available Nicotine exerts its oncogenic effects through the binding to nicotinic acetylcholine receptors (nAChRs and the activation of downstream pathways that block apoptosis and promote neo-angiogenesis. The nAChRs of the α7 subtype are present on a wide variety of cancer cells and their inhibition by cobra venom neurotoxins has been proposed in several articles and reviews as a potential innovative lung cancer therapy. However, since part of the published results was recently retracted, we believe that the antitumoral activity of cobra venom neurotoxins needs to be independently re-evaluated.We determined the activity of α-neurotoxins from Naja atra (short-chain neurotoxin, α-cobrotoxin and Naja kaouthia (long-chain neurotoxin, α-cobratoxin in vitro by cytotoxicity measurements in 5 lung cancer cell lines, by colony formation assay with α7nAChRs expressing and non-expressing cell lines and in vivo by assessing tumor growth in an orthotopic Non-Obese Diabetic/Severe Combined Immunodeficient (NOD/SCID mouse model system utilizing different treatment schedules and dosages.No statistically significant reduction in tumor growth was observed in the treatment arms in comparison to the control for both toxins. Paradoxically α-cobrotoxin from Naja atra showed the tendency to enhance tumor growth although, even in this case, the statistical significance was not reached.In conclusion our results show that, in contrast with other reports, the nAChR inhibitors α-cobratoxin from N. kaouthia and α-cobrotoxin from N. atra neither suppressed tumor growth nor prolonged the survival of the treated animals.

[Co-occurence of indol-producing bacterial strains in the vagina of women infected with Chlamydia trachomatis].

Science.gov (United States)

Romanik, Małgorzata; Martirosian, Gayane; Wojciechowska-Wieja, Anna; Cieślik, Katarzyna; Kaźmierczak, Wojciech

2007-08-01

The aim of this study was to determine if cervicitis, caused by Chlamydia trachomatis (C. trachomatis), has an influence on the frequency of occurrence of selected aerobic and anaerobic bacterial strains, connected with etiology of aerobic vaginitis (AV) and bacterial vaginosis (BV). Indole-producing bacteria have received particular attention due to their possibly inductive role in chronic cervicitis caused by C. trachomatis. The swabs from vagina and cervical canal have been obtained from 122 women (aged 18-40). The presence of C. trachomatis antigen had been detected and diagnosed with the help of direct immunofluorescence, BV with Amesl and Nugent criteria, whereas the AV with Donders criteria. The identification of the bacterial strains isolated from vagina has been performed according to classical microbiological diagnostics. Disruption of vaginal microflora (4-10 in Nugent score) was determined in 11,5% of observed women. AV was diagnosed in 4.5% women with chlamydial cervicitis, BV was diagnosed in 10.9% and 5.45% of these women, on the basis of Amsel and Nugent criteria respectively. Indole-producing bacterial strains connected with BV and AV (Peptostreptococcus anaerobius, Propionibacterium acnes, Escherichia coli) have been isolated significantly more often from vagina of women infected with C trachomatis (p = 0.0405, chi2 = 4.20) and these findings confirm co-importance of indole-producing bacterial strains in cervicitis caused by C trachomatis .

Structural identification of lipopeptide biosurfactants produced by Bacillus subtilis strains grown on the media obtained from renewable natural resources.

Science.gov (United States)

Paraszkiewicz, Katarzyna; Bernat, Przemysław; Kuśmierska, Anna; Chojniak, Joanna; Płaza, Grażyna

2018-03-01

The aim of the study was to identify and characterize lipopeptide (LP) biosurfactants produced by two Bacillus subtilis strains (KP7 and I'-1a) grown on various media prepared from renewable natural resources: two different brewery wastewaters (BW#4 and BW#6), 2% beet molasses (M), apple peels extract (APE) supplemented with 0.25% of yeast extract (YE) or 0.25% peptone (P), and similarly supplemented carrot peels extract (CPE). In all used media both strains retained their individual LP production signature characterized by surfactin and iturin overproduction exhibited by KP7 and I'-1a strain, respectively. The production level and the structural diversity of synthesized LPs were dependent on the medium composition. In the CPE+YE medium it was higher than the yield obtained in Luria-Bertani (140.6 and 100.3 mg L -1 , respectively). Surfactins were produced by both strains as a mixture of four homologues (C13-C16) with the domination of variant C14. All other broths prepared from renewable resources strongly stimulated the iturin production by I'-1a strain with the exception of BW media. The highest iturin concentration (428.7 mg L -1 ) obtained in the CPE+P culture of I'-1a strain was about seven-fold higher than in LB. In all cultures only iturin A was identified. Among four iturin homologues (C13-16) produced by I'-1a strain, the highest relative contents of C16 variant (70-80%) were calculated for samples obtained from APE+P and CPE+P media. The obtained data indicate that the waste composition has an influence on both the types and amounts of biosurfactants produced by studied B. subtilis strains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative Genomic and Phylogenetic Analysis of a Shiga Toxin Producing Shigella sonnei (STSS Strain

Directory of Open Access Journals (Sweden)

Domonkos Sváb

2017-05-01

Full Text Available Shigella strains are important agents of bacillary dysentery, and in recent years Shigella sonnei has emerged as the leading cause of shigellosis in industrialized and rapidly developing countries. More recently, several S. sonnei and Shigella flexneri strains producing Shiga toxin (Stx have been reported from sporadic cases and from an outbreak in America. In the present study we aimed to shed light on the evolution of a recently identified Shiga toxin producing S. sonnei (STSS isolated in Europe. Here we report the first completely assembled whole genome sequence of a multidrug resistant (MDR Stx-producing S. sonnei (STSS clinical strain and reveal its phylogenetic relations. STSS 75/02 proved to be resistant to ampicillin, streptomycin, tetracycline, chloramphenicol, thrimetoprim, and sulfomethoxazol. The genome of STSS 75/02 contains a 4,891,717 nt chromosome and seven plasmids including the 214 kb invasion plasmid (pInv harboring type III secretion system genes and associated effectors. The chromosome harbors 23 prophage regions including the Stx1 converting prophage. The genome carries all virulence determinants necessary for an enteroinvasive lifestyle, as well as the Stx1 encoding gene cluster within an earlier described inducible converting prophage. In silico SNP genotyping of the assembled genome as well as 438 complete or draft S. sonnei genomes downloaded from NCBI GenBank revealed that S. sonnei 75/02 belongs to the more recently diverged global MDR lineage (IIIc. Targeted screening of 1131 next-generation sequencing projects taken from NCBI Short Read Archive of confirms that only a few S. sonnei isolates are Stx positive. Our results suggest that the acquisition of Stx phages could have occurred in different environments as independent events and that multiple horizontal transfers are responsible for the appearance of Stx phages in S. sonnei strains.

Selection of bacteriocin producer strains of lactic acid bacteria from a dairy environment.

Science.gov (United States)

Lasagno, M; Beoleito, V; Sesma, F; Raya, R; Font de Valdez, G; Eraso, A

2002-01-01

Two strains showing bacteriocin production were selected from a total of 206 lactic acid bacteria isolated from samples of milk, milk serum, whey and homemade cheeses in Southern Cordoba, Argentina. This property was detected by means of well diffusion assays. The strains were identified as Enterococcus hirae and Enterococcus durans. The protein nature of those substances was proved by showing their sensitivity to type IV and XXV proteases, papaine, trypsin, pepsin and K proteinase. The bacteriocins inhibited the growth of Listeria monocytogenes, Bacillus cereus, Clostridium perfringes and two strains of Staphylococcus aureus, an A-enterotoxin and a B-enterotoxin producers. All of these bacteria are common pathogens usually associated with food borne diseases (ETA). These lactic acid bacteria or their bacteriocins could be suitable candidates for food preservation and specially useful in the our regional dairy industry.

Isolation and amino acid sequence of a short-chain neurotoxin from an Australian elapid snake, Pseudechis australis.

OpenAIRE

Takasaki, C; Tamiya, N

1985-01-01

A short-chain neurotoxin Pseudechis australis a (toxin Pa a) was isolated from the venom of an Australian elapid snake Pseudechis australis (king brown snake) by sequential chromatography on CM-cellulose, Sephadex G-50 and CM-cellulose columns. Toxin Pa a has an LD50 (intravenous) value of 76 micrograms/kg body wt. in mice and consists of 62 amino acid residues. The amino acid sequence of Pa a shows considerable homology with those of short-chain neurotoxins of elapid snakes, especially of tr...

Isolation and characterisation of an enterocin P-producing Enterococcus lactis strain from a fresh shrimp (Penaeus vannamei).

Science.gov (United States)

Ben Braïek, Olfa; Ghomrassi, Hamdi; Cremonesi, Paola; Morandi, Stefano; Fleury, Yannick; Le Chevalier, Patrick; Hani, Khaled; Bel Hadj, Omrane; Ghrairi, Taoufik

2017-06-01

Screening for lactic acid bacteria (LAB) from fresh shrimp samples (Penaeus vannamei) collected from retail seafood markets in the Tunisian's coast, resulted in the isolation of an Enterococcus strain termed Q1. This strain was selected for its antagonistic activity against pathogenic bacteria such as Listeria monocytogenes, Pseudomonas aeruginosa, Lactococcus garvieae and against fungi (Aspergillus niger and Fusarium equiseti). The Q1 strain was characterised using standard morphological and biochemical tests, growth assays at different temperatures, pH and salinity. 16S rRNA, rpoA and pheS gene sequencing, as well as the 16S-23S rRNA intergenic spacer analyses, were combined to identify strain Q1 as a strain of Enterococcus lactis. The bacteriocin produced by E. lactis Q1 is thermostable, active in the pH range from 4.0 to 9.0 and has a bactericidal mode of action. The enterocin P structural gene was detected by specific PCR in strain E. lactis Q1, which is in good agreement with SDS-PAGE data of the purified bacteriocin. A lack of significant antibiotic resistance genes and virulence determinants was confirmed by specific PCRs. This work provides the first description of an enterocin P producer E. lactis strain isolated from a fresh shrimp. Based on its safety properties (absence of haemolytic activity, virulence factors and antibiotic resistance genes), this strain has the potential to be used as a natural additive or adjunct protective culture in food biopreservation and/or probiotic culture.

Formation of Highly Twisted Ribbons in a Carboxymethylcellulase Gene-Disrupted Strain of a Cellulose-Producing Bacterium

Science.gov (United States)

Sugano, Yasushi; Shoda, Makoto; Sakakibara, Hitoshi; Oiwa, Kazuhiro; Tuzi, Satoru; Imai, Tomoya; Sugiyama, Junji; Takeuchi, Miyuki; Yamauchi, Daisuke

2013-01-01

Cellulases are enzymes that normally digest cellulose; however, some are known to play essential roles in cellulose biosynthesis. Although some endogenous cellulases of plants and cellulose-producing bacteria are reportedly involved in cellulose production, their functions in cellulose production are unknown. In this study, we demonstrated that disruption of the cellulase (carboxymethylcellulase) gene causes irregular packing of de novo-synthesized fibrils in Gluconacetobacter xylinus, a cellulose-producing bacterium. Cellulose production was remarkably reduced and small amounts of particulate material were accumulated in the culture of a cmcax-disrupted G. xylinus strain (F2-2). The particulate material was shown to contain cellulose by both solid-state 13C nuclear magnetic resonance analysis and Fourier transform infrared spectroscopy analysis. Electron microscopy revealed that the cellulose fibrils produced by the F2-2 cells were highly twisted compared with those produced by control cells. This hypertwisting of the fibrils may reduce cellulose synthesis in the F2-2 strains. PMID:23243308

Discovering potential Streptomyces hormone producers by using disruptants of essential biosynthetic genes as indicator strains.

Science.gov (United States)

Thao, Nguyen B; Kitani, Shigeru; Nitta, Hiroko; Tomioka, Toshiya; Nihira, Takuya

2017-10-01

Autoregulators are low-molecular-weight signaling compounds that control the production of many secondary metabolites in actinomycetes and have been referred to as 'Streptomyces hormones'. Here, potential producers of Streptomyces hormones were investigated in 40 Streptomyces and 11 endophytic actinomycetes. Production of γ-butyrolactone-type (IM-2, VB) and butenolide-type (avenolide) Streptomyces hormones was screened using Streptomyces lavendulae FRI-5 (ΔfarX), Streptomyces virginiae (ΔbarX) and Streptomyces avermitilis (Δaco), respectively. In these strains, essential biosynthetic genes for Streptomyces hormones were disrupted, enabling them to respond solely to the externally added hormones. The results showed that 20% of each of the investigated strains produced IM-2 and VB, confirming that γ-butyrolactone-type Streptomyces hormones are the most common in actinomycetes. Unlike the γ-butyrolactone type, butenolide-type Streptomyces hormones have been discovered in recent years, but their distribution has been unclear. Our finding that 24% of actinomycetes (12 of 51 strains) showed avenolide activity revealed for the first time that the butenolide-type Streptomyces hormone is also common in actinomycetes.

An application in cheddar cheese manufacture for a strain of Lactococcus lactis producing a novel broad-spectrum bacteriocin, lacticin 3147.

Science.gov (United States)

Ryan, M P; Rea, M C; Hill, C; Ross, R P

1996-01-01

Lactococcus lactis DPC3147, a strain isolated from an Irish kefir grain, produces a bacteriocin with a broad spectrum of inhibition. The bacteriocin produced is heat stable, particularly at a low pH, and inhibits nisin-producing (Nip+) lactococci. On the basis of the observation that the nisin structural gene (nisA) does not hybridize to DPC3147 genomic DNA, the bacteriocin produced was considered novel and designated lacticin 3147. The genetic determinants which encode lacticin 3147 are contained on a 63-kb plasmid, which was conjugally mobilized to a commercial cheese starter, L. lactis subsp. cremoris DPC4268. The resultant transconjugant, DPC4275, both produces and is immune to lacticin 3147. The ability of lacticin 3147-producing lactococci to perform as cheddar cheese starters was subsequently investigated in cheesemaking trials. Bacteriocin-producing starters (which included the transconjugant strain DPC4275) produced acid at rates similar to those of commercial strains. The level of lacticin 3147 produced in cheese remained constant over 6 months of ripening and correlated with a significant reduction in the levels of nonstarter lactic acid bacteria. Such results suggest that these starters provide a means of controlling developing microflora in ripened fermented products. PMID:8593062

Cyanobacterial Neurotoxin β-N-Methylamino-L-alanine (BMAA in Shark Fins

Directory of Open Access Journals (Sweden)

John Pablo

2012-02-01

Full Text Available Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA.

Mass Spectrometric Identification and Differentiation of Botulinum Neurotoxins through Toxin Proteomics.

Science.gov (United States)

Kalb, Suzanne R; Barr, John R

2013-08-01

Botulinum neurotoxins (BoNTs) cause the disease botulism, which can be lethal if untreated. There are seven known serotypes of BoNT, A-G, defined by their response to antisera. Many serotypes are distinguished into differing subtypes based on amino acid sequence and immunogenic properties, and some subtypes are further differentiated into toxin variants. Toxin characterization is important as different types of BoNT can respond differently to medical countermeasures for botulism, and characterization of the toxin can aid in epidemiologic and forensic investigations. Proteomic techniques have been established to determine the serotype, subtype, or toxin variant of BoNT. These techniques involve digestion of the toxin into peptides, tandem mass spectrometric (MS/MS) analysis of the peptides, and database searching to identify the BoNT protein. These techniques demonstrate the capability to detect BoNT and its neurotoxin-associated proteins, and differentiate the toxin from other toxins which are up to 99.9% identical in some cases. This differentiation can be accomplished from toxins present in a complex matrix such as stool, food, or bacterial cultures and no DNA is required.

Draft Genome Sequence of Komagataeibacter intermedius Strain AF2, a Producer of Cellulose, Isolated from Kombucha Tea.

Science.gov (United States)

Dos Santos, Renato Augusto Corrêa; Berretta, Andresa Aparecida; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues; Goldman, Gustavo H; Riaño-Pachón, Diego M

2015-12-03

Here, we present the draft genome sequence of Komagataeibacter intermedius strain AF2, which was isolated from Kombucha tea and is capable of producing cellulose, although at lower levels compared to another bacterium from the same environment, K. rhaeticus strain AF1. Copyright © 2015 dos Santos et al.

Genomic mutational analysis of the impact of the classical strain improvement program on ß–lactam producing Penicillium chrysogenum

NARCIS (Netherlands)

Salo, O.V.; Ries, M.; Medema, M.H.; Lankhorst, P.P.; Vreeken, R.J.; Bovenberg, R.A.L.; Driessen, A.J.M.

2015-01-01

Background Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of ß–lactams. The high ß–lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This involved

Strain-specific transmission in an outbreak of ESBL-producing Enterobacteriaceae in the hemato-oncology care unit: a cohort study.

Science.gov (United States)

Uemura, Makiko; Imataki, Osamu; Uchida, Shumpei; Nakayama-Imaohji, Haruyuki; Ohue, Yukiko; Matsuka, Harumi; Mori, Hatsune; Dobashi, Hiroaki; Kuwahara, Tomomi; Kadowaki, Norimitsu

2017-01-05

Extended-spectrum β-lactamase (ESBL)-producing bacteria are resistant to several types of antibiotics excluding carbapenems. A transmissibility of ESBL-producing Enterobacteriaceae would be depending on each bacterial property, however, that has not been elucidated in clinical setting. In this study, we attempted to identify the source of an outbreak of ESBL-producing bacteria in a medical oncology and immunology care unit. An ESBL-producing Enterobacteriaceae (ESBL-E) outbreak observed between July 2012 and August 2012 in Kagawa University Hospital was surveyed using various molecular microbiology techniques. We used Pulsed-field gel electrophoresis (PFGE), PCR-based ESBL gene typing, and direct sequence of ESBL gene as molecular microbiology typing method to distinguish each strain. The typical prevalence of ESBL-E isolation in the unit was 7.0 per month (1.7 per week). The prevalence of ESBL-E isolation during the target research period was 20.0 per month (5.0 per week). In total, 19 isolates (11 K. pneumoniae and 8 E. coli) were obtained from clinical samples, including four control strains (two each of both bacteria), that were physically different from those obtained from other inpatient units in our hospital. Pulsed-field gel electrophoresis (PFGE) for K. pneumoniae (digested by XbaI) produced similar patterns excluding one control strain. PCR classification of the ESBL gene for K. pneumoniae revealed that all strains other than the control strain carried SHV and CTX-M-9. This result was reconfirmed by direct DNA sequencing. Although the outbreak of K. pneumoniae was considered to be "clonal," PFGE and PCR classification of the ESBL genes for E. coli uncovered at least six different "non-clonal" strains possessing individual ESBL gene patterns. According to the result of an antibiogram, the pattern of antimicrobial susceptibility was more variable for K. pneumoniae than for E. coli. Typing by PFGE and ESBL gene PCR analysis is practical for discriminating

A New Bacillus licheniformis Mutant Strain Producing Serine Protease Efficient for Hvdrolvqis of Sov Meal Proteins.

Science.gov (United States)

Kostyleva, E V; Sereda, A S; Velikoretskaya, I A; Nefedova, L I; Sharikov, A Yu; Tsurikova, N V; Lobanov, N S; Semenova, M V; Sinitsyn, A P

2016-07-01

Induced mutagenesis with y-irradiation of the industrial strain Bacillus licheniformis-60 VKM B-2366,D was used to obtain a new highly active producer of an extracellular serine protease, Bacillus licheni- formis7 145. Samples of dry.concentrated preparations of serine protease produced by the original and mutant strains were obtained, and identity of their protein composition was'established. Alkaline serine protease sub- tilisin DY was the main component of the preparations. The biochemical and physicochemical properties of the Protolkheterm-145 enzyme preparation obtained from the mutant strain were studied. It exhibited pro- teolytic activity (1.5 times higher than the preparation from the initial strain) within broad ranges of pH (5- 11) and temperature (30-70'C).-Efficient hydrolysis of extruded soy meal protein at high concentrations (2 to 50%) in-the reaction mixture was.the main advantage of the Protolikheterm 145 preparation. Compared to,. the preparation obtained using the initial strain, the new preparation with increased proteolytic-activity pro- vided for more complete hydrolysis of the main non-nutritious soy,proteins.(glycinin and 0-conglycinin) with the yield of soluble protein increased by 19-28%, which decreased the cost of bioconversion of the protein- aceous material and indicated promise of the new preparation in resource-saving technologies for processing soy meals and cakes.

Rapid microfluidic assay for the detection of botulinum neurotoxin in animal sera

Science.gov (United States)

The potent botulinum neurotoxins (BoNTs) represent a threat to public health and safety. Botulism is a disease caused by BoNT intoxication that results in muscle paralysis that can be fatal. Sensitive assays capable of detecting BoNTs from different substrates and settings are essential to limit f...

Clostridium botulinum group I strain genotyping by 15-locus multilocus variable-number tandem-repeat analysis

NARCIS (Netherlands)

Fillo, S.; Giordani, F.; Anniballi, F.; Gorgé, O.; Ramisse, V.; Vergnaud, G.; Riehm, J.M.; Scholz, H.C.; Splettstoesser, W.D.; Kieboom, J.; Olsen, J.-S.; Fenicia, L.; Lista, F.

2011-01-01

Clostridium botulinum is a taxonomic designation that encompasses a broad variety of spore-forming, Gram-positive bacteria producing the botulinum neurotoxin (BoNT). C. botulinum is the etiologic agent of botulism, a rare but severe neuroparalytic disease. Fine-resolution genetic characterization of

Annealing Behavior of Nanostructured Aluminum Produced by Cold Rolling to Ultrahigh Strains

DEFF Research Database (Denmark)

Cao, W.Q.; Godfrey, A.; Hansen, Niels

2009-01-01

The isochronal annealing behavior of nanostructured commercial purity aluminum (AA1100 and AA1200) produced by either cold rolling (CR) or accumulative roll bonding (ARB) up to ultrahigh strains of about 99.5 pct reduction in thickness has been studied in the temperature range from 200 degrees C...... to 420 degrees C. Microstructural and texture measurements were made using data from electron backscatter diffraction (EBSD) investigations, and the change in mechanical strength was followed using hardness measurements. A large effect of the rolling strain is observed on recovery at temperatures below...... for analyzing the uniformity of the structural coarsening, based on analysis of the crystallite size distribution with respect to the mode, is described. The analysis demonstrates that annealing leads to locally nonuniform changes in the microstructure, and to a description of the annealing process...

Typing clinical and animal environment Aspergillus fumigatus gliotoxin producer strains isolated from Brazil by PCR-RFLP markers.

Science.gov (United States)

Soleiro, C A; Pena, G A; Cavaglieri, L R; Coelho, I; Keller, L M; Dalcero, A M; Rosa, C A R

2013-12-01

Aspergillus fumigatus, a well-known human and animal pathogen causing aspergillosis, has been historically identified by morphological and microscopic features. However, recent studies have shown that species identification on the basis of morphology alone is problematic. The aim of this work was to confirm the taxonomic state at specie level of a set of clinical (human and animal) and animal environment A. fumigatus strains identified by morphological criteria applying a PCR-RFLP assay by an in silico and in situ analysis with three restriction enzymes. The A. fumigatus gliotoxin-producing ability was also determined. Previous to the in situ PCR-RFLP analysis, an in silico assay with BccI, MspI and Sau3AI restriction enzymes was carried out. After that, these enzymes were used for in situ assay. All A. fumigatus strains isolated from corn silage, human aspergillosis and bovine mastitis and high per cent of the strains isolated from cereals, animal feedstuff and sorghum silage were able to produce high gliotoxin levels. Also, all these strains identified by morphological criteria as A. fumigatus, regardless of its isolation source, had band patterns according to A. fumigatus sensu stricto by PCR-RFLP markers. Aspergillus fumigatus is a well-known human and animal pathogen causing aspergillosis. In this study, clinical (human and animal) and animal environment strains were able to produce high gliotoxin levels and had band profiles according to A. fumigatus sensu stricto by PCR-RFLP markers. The results obtained here suggest that strains involved in human and animal aspergillosis could come from the animal environment in which A. fumigatus is frequently found. Its presence in animal environments could affect animal health and productivity; in addition, there are risks of contamination for rural workers during handling and storage of animal feedstuffs. © 2013 The Society for Applied Microbiology.

Butyricicoccus pullicaecorum, a butyrate producer with probiotic potential, is intrinsically tolerant to stomach and small intestine conditions.

Science.gov (United States)

Geirnaert, Annelies; Steyaert, Alix; Eeckhaut, Venessa; Debruyne, Bo; Arends, Jan B A; Van Immerseel, Filip; Boon, Nico; Van de Wiele, Tom

2014-12-01

Butyrate has several beneficial properties that are essential to maintain gastrointestinal health. Therefore butyrate-producing bacteria are seen as the next generation of probiotics. The butyrate-producing bacterium Butyricicoccus pullicaecorum (a clostridial cluster IV strain) is such a promising probiotic candidate for people suffering from inflammatory bowel disease. To exert its beneficial properties, it is crucial that B. pullicaecorum survives the harsh conditions of the upper gastrointestinal tract to arrive in the colon in a viable and metabolically active state. Before developing a stable formulation of B. pullicaecorum for oral administration, it is important to know its intrinsic acid and bile tolerance. We monitored the survival during and short chain fatty acid production after incubation in conditions simulating the stomach and small intestine using in vitro batch experiments. In case of acid conditions (pH 2 and pH 3), B. pullicaecorum was viable and active but not cultivable. Cultivability was restored during subsequent small intestine conditions. Importantly, bile and pancreatic juice had no lethal effect. Milk, as a suspension medium, only had a protective effect on the cultivability during the first hour at pH 2. B. pullicaecorum was still metabolically active after upper gastrointestinal conditions and produced short chain fatty acids, but a shift from butyrate to acetate production was observed. Although the butyrate-producing anaerobe B. pullicaecorum showed good intrinsic acid and bile tolerance in terms of viability and metabolic activity, colonization efficiency and butyrate production under colon conditions is needed to further evaluate its probiotic potential. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genome Sequence of Lactobacillus saerimneri 30a (Formerly Lactobacillus sp. Strain 30a), a Reference Lactic Acid Bacterium Strain Producing Biogenic Amines

NARCIS (Netherlands)

Romano, Andrea; Trip, Hein; Campbell-Sills, Hugo; Bouchez, Olivier; Sherman, David; Lolkema, Juke S.; Lucas, Patrick M.

2013-01-01

Lactobacillus sp. strain 30a (Lactobacillus saerimneri) produces the biogenic amines histamine, putrescine, and cadaverine by decarboxylating their amino acid precursors. We report its draft genome sequence (1,634,278 bases, 42.6% G+C content) and the principal findings from its annotation, which

KPC and VIM producing Enterobacter cloacae strain from a hospital in northeastern Venezuela.

Science.gov (United States)

Martínez, Dianny; Marcano, Daniel; Rodulfo, Hectorina; Salgado, Nurys; Cuaical, Nirvia; Rodriguez, Lucy; Caña, Luisa; Medina, Belkis; Guzman, Militza; De Donato, Marcos

2015-06-01

An 83-year-old male patient is admitted to the central hospital in Cumana, Venezuela with severe urinary infection, history of hospitalizaions and prolonged antimicrobial treatments. A strain of Enterobacter cloacae was isolated showing resistance to multiple types of antibiotics (only sensitive to gentamicin), with phenotype of serine- and metallo-carbapenemases. Both, bla(VIM-2) and bla(KPC) genes were detected in the isolate. This is the first report of an Enterobacteriaceae species producing both KPC carbapenemase and VIM metallo carbapenemase in Venezuela. This finding has a great clinical and epidemiological impact in the region, because of the feasibility of transferring these genes, through mobile elements to other strains of Enterobacter and to other infection-causing species of bacteria.

Identification of novel linear megaplasmids carrying a ß-lactamase gene in neurotoxigenic Clostridium butyricum type E strains.

Directory of Open Access Journals (Sweden)

Giovanna Franciosa

Full Text Available Since the first isolation of type E botulinum toxin-producing Clostridium butyricum from two infant botulism cases in Italy in 1984, this peculiar microorganism has been implicated in different forms of botulism worldwide. By applying particular pulsed-field gel electrophoresis run conditions, we were able to show for the first time that ten neurotoxigenic C. butyricum type E strains originated from Italy and China have linear megaplasmids in their genomes. At least four different megaplasmid sizes were identified among the ten neurotoxigenic C. butyricum type E strains. Each isolate displayed a single sized megaplasmid that was shown to possess a linear structure by ATP-dependent exonuclease digestion. Some of the neurotoxigenic C. butyricum type E strains possessed additional smaller circular plasmids. In order to investigate the genetic content of the newly identified megaplasmids, selected gene probes were designed and used in Southern hybridization experiments. Our results revealed that the type E botulinum neurotoxin gene was chromosome-located in all neurotoxigenic C. butyricum type E strains. Similar results were obtained with the 16S rRNA, the tetracycline tet(P and the lincomycin resistance protein lmrB gene probes. A specific mobA gene probe only hybridized to the smaller plasmids of the Italian C. butyricum type E strains. Of note, a ß-lactamase gene probe hybridized to the megaplasmids of eight neurotoxigenic C. butyricum type E strains, of which seven from clinical sources and the remaining one from a food implicated in foodborne botulism, whereas this ß-lactam antibiotic resistance gene was absent form the megaplasmids of the two soil strains examined. The widespread occurrence among C. butyricum type E strains associated to human disease of linear megaplasmids harboring an antibiotic resistance gene strongly suggests that the megaplasmids could have played an important role in the emergence of C. butyricum type E as a human

Probiotic Microorganisms Inhibit Epithelial Cell Internalization of Botulinum Neurotoxin Serotype A

Science.gov (United States)

Lam, Tina I.; Tam, Christina C.; Stanker, Larry H.; Cheng, Luisa W.

2016-01-01

Botulinum neurotoxins (BoNTs) are some of the most poisonous natural toxins known to man and are threats to public health and safety. Previous work from our laboratory showed that both BoNT serotype A complex and holotoxin can bind and transit through the intestinal epithelia to disseminate in the blood. The timing of BoNT/A toxin internalization was shown to be comparable in both the Caco-2 in vitro cell culture and in the oral mouse intoxication models. Probiotic microorganisms have been extensively studied for their beneficial effects in not only maintaining the normal gut mucosa but also protection from allergens, pathogens, and toxins. In this study, we evaluate whether probiotic microorganisms will block BoNT/A uptake in the in vitro cell culture system using Caco-2 cells. Several probiotics tested (Saccharomyces boulardii, Lactobacillus acidophilus, Lactobacillus rhamnosus LGG, and Lactobacillus reuteri) blocked BoNT/A uptake in a dose-dependent manner whereas a non-probiotic strain of Escherichia coli did not. We also showed that inhibition of BoNT/A uptake was not due to the degradation of BoNT/A nor by sequestration of toxin via binding to probiotics. These results show for the first time that probiotic treatment can inhibit BoNT/A binding and internalization in vitro and may lead to the development of new therapies. PMID:27999281

Probiotic Microorganisms Inhibit Epithelial Cell Internalization of Botulinum Neurotoxin Serotype A

Directory of Open Access Journals (Sweden)

Tina I. Lam

2016-12-01

Full Text Available Botulinum neurotoxins (BoNTs are some of the most poisonous natural toxins known to man and are threats to public health and safety. Previous work from our laboratory showed that both BoNT serotype A complex and holotoxin can bind and transit through the intestinal epithelia to disseminate in the blood. The timing of BoNT/A toxin internalization was shown to be comparable in both the Caco-2 in vitro cell culture and in the oral mouse intoxication models. Probiotic microorganisms have been extensively studied for their beneficial effects in not only maintaining the normal gut mucosa but also protection from allergens, pathogens, and toxins. In this study, we evaluate whether probiotic microorganisms will block BoNT/A uptake in the in vitro cell culture system using Caco-2 cells. Several probiotics tested (Saccharomyces boulardii, Lactobacillus acidophilus, Lactobacillus rhamnosus LGG, and Lactobacillus reuteri blocked BoNT/A uptake in a dose-dependent manner whereas a non-probiotic strain of Escherichia coli did not. We also showed that inhibition of BoNT/A uptake was not due to the degradation of BoNT/A nor by sequestration of toxin via binding to probiotics. These results show for the first time that probiotic treatment can inhibit BoNT/A binding and internalization in vitro and may lead to the development of new therapies.

Draft genome sequence of a thermostable, alkaliphilic α-amylase and protease producing Bacillus amyloliquefaciens strain KCP2.

Science.gov (United States)

Prajapati, Vimalkumar S; Ray, Sanket; Narayan, Jitendra; Joshi, Chaitanya C; Patel, Kamlesh C; Trivedi, Ujjval B; Patel, R M

2017-12-01

Bacillus amyloliquefaciens strain KCP2 was isolated from municipal food waste samples collected in Vallabh Vidyanagar, Gujarat, India. Strain KCP2 is noteworthy due to its ability to produce a thermostable, alkaliphilic α-amylase and a protease. These enzymes have importance in several industrial processes including bread making, brewing, starch processing, pharmacy, and textile industries. Whole genome sequencing of strain KCP2 showed that the estimated genome size was 3.9 Mb, the G + C content was 46%, and it coded for 4113 genes.

Isolation and identification of biosurfactant-producing strains from the genus Pseudomonas aeruginosa and antibacterial effects of biosurfactant production in vitro

Directory of Open Access Journals (Sweden)

Salman Ahmady-Asbchin

2013-01-01

Full Text Available Introduction: Biosurfactants are amphiphilic biological compounds produced extracellularly or as part of the cell membranes by a variety of microorganisms. Because of their use in various industries, they are of a particular importance. The aim of this study was to identify a strain of bacteria of the genus Pseudomonas aeruginosa biosurfactant producers. Materials and methods: In this study, different samples of oil, water and soil contaminated with oil were prepared. Hemolytic activity, emulsification activity and measurement of surface tension were used and selected strains were identified by biochemical tests. The nature and effect of antibacterial biosurfactant was evaluated for strain selection.Results: In this study, eighty eight bacterial strains were isolated. Twenty four strains were isolated from the isolated strains with hemolytic activity. Among which, 14 strains have emulsification activity more than 70% and at last four strains reached surface tension to be less than 40 mN/m. Selected strain based on biochemical tests was recognized as a Pseudomonas aeruginosa. The nature of biosurfactant was determined by TLC, and proved to be of glycolipid kind. Therefore, the produced biosurfactant of the selected strain had antibacterial activity against six bacterial infectious. Sensitive bacteria to the effects of biosurfactant extract of Pseudomonas aeruginosa83, was Staphylococcus aureus and the most resistant bacteria to these extract, was the Proteus mirabilis. The results of MIC, MBC showed that MIC of the extract in concentration of 63 and 125 mg/ml on Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus respectively. Also, the MBC were extract in concentration of 63 and 125mg/ml on Staphylococcus epidermidis and Staphylococcus aureus respectively.Discussion and conclusion: Pseudomonas aeruginosa had high potential in reducing the surface tension and biosurfactant extracted had high antibacterial effects. Therefore, it

An update on neurotoxin products and administration methods.

Science.gov (United States)

Lanoue, Julien; Dong, Joanna; Do, Timothy; Goldenberg, Gary

2016-09-01

Since onabotulinumtoxinA for nonsurgical aesthetic enhancement of glabellar lines was initially reported, the popularity of botulinum neurotoxin (BoNT) products among both clinicians and consumers has rapidly grown, and we have seen several additional BoNT formulations enter the market. As the demand for minimally invasive cosmetic procedures continues to increase, we will see the introduction of additional formulations of BoNT products as well as new delivery devices and administration techniques. In this article, we provide a brief update on current and upcoming BoNT products and also review the literature on novel administration methods based on recently published studies.

Correction of Malocclusion by Botulinum Neurotoxin Injection into Masticatory Muscles

OpenAIRE

Seok, Hyun; Kim, Seong-Gon

2018-01-01

Botulinum toxin (BTX) is a neurotoxin, and its injection in masticatory muscles induces muscle weakness and paralysis. This paralytic effect of BTX induces growth retardation of the maxillofacial bones, changes in dental eruption and occlusion state, and facial asymmetry. Using masticatory muscle paralysis and its effect via BTX, BTX can be used for the correction of malocclusion after orthognathic surgery and mandible fracture. The paralysis of specific masticatory muscles by BTX injection r...

Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels

Directory of Open Access Journals (Sweden)

Xuefang Guan

Full Text Available ABSTRACT Objective To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. Methods The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. Results The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940 and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v in simulated gastric juice (pH 2.5 for 2 h and in simulated intestinal fluid (pH 8.0 for 3 h. The auto-aggregation rate increased to 87.74% after 24 h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. Conclusion These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health.

Insights from the genome of a high alkaline cellulase producing Aspergillus fumigatus strain obtained from Peruvian Amazon rainforest.

Science.gov (United States)

Paul, Sujay; Zhang, Angel; Ludeña, Yvette; Villena, Gretty K; Yu, Fengan; Sherman, David H; Gutiérrez-Correa, Marcel

2017-06-10

Here, we report the complete genome sequence of a high alkaline cellulase producing Aspergillus fumigatus strain LMB-35Aa isolated from soil of Peruvian Amazon rainforest. The genome is ∼27.5mb in size, comprises of 228 scaffolds with an average GC content of 50%, and is predicted to contain a total of 8660 protein-coding genes. Of which, 6156 are with known function; it codes for 607 putative CAZymes families potentially involved in carbohydrate metabolism. Several important cellulose degrading genes, such as endoglucanase A, endoglucanase B, endoglucanase D and beta-glucosidase, are also identified. The genome of A. fumigatus strain LMB-35Aa represents the first whole sequenced genome of non-clinical, high cellulase producing A. fumigatus strain isolated from forest soil. Copyright © 2017 Elsevier B.V. All rights reserved.

Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

Directory of Open Access Journals (Sweden)

Soares Márcia M.C.N.

1999-01-01

Full Text Available One hundred sixty eight bacterial strains, isolated from soil and samples of vegetable in decomposition, were screened for the use of citrus pectin as the sole carbon source. 102 were positive for pectinase depolymerization in assay plates as evidenced by clear hydrolization halos. Among them, 30% presented considerable pectinolytic activity. The cultivation of these strains by submerged and semi-solid fermentation for polygalacturonase production indicated that five strains of Bacillus sp produced high quantities of the enzyme. The physico-chemical characteristics, such as optimum pH of 6.0 - 7.0, optimum temperatures between 45oC and 55oC, stability at temperatures above 40oC and in neutral and alkaline pH, were determined.

Isolation and characterization of large spectrum and multiple bacteriocin-producing Enterococcus faecium strain from raw bovine milk.

Science.gov (United States)

Gaaloul, N; ben Braiek, O; Hani, K; Volski, A; Chikindas, M L; Ghrairi, T

2015-02-01

To assess the antimicrobial properties of lactic acid bacteria from Tunisian raw bovine milk. A bacteriocin-producing Enterococcus faecium strain was isolated from raw cow milk with activity against Gram-positive and Gram-negative bacteria. Antimicrobial substances produced by this strain were sensitive to proteolytic enzymes and were thermostable and resistant to a broad range of pH (2-10). Mode of action of antimicrobial substances was determined as bactericidal. Maximum activity was reached at the end of the exponential growth phase when checked against Listeria ivanovii BUG 496 (2366.62 AU ml(-1)). However, maximum antimicrobial activity against Pseudomonas aeruginosa 28753 was recorded at the beginning of the exponential growth phase. Enterococcus faecium GGN7 was characterized as free from virulence factors and was susceptible to tested antibiotics. PCR analysis of the micro-organism's genome revealed the presence of genes coding for enterocins A and B. Mass spectrometry analysis of RP-HPLC active fractions showed molecular masses corresponding to enterocins A (4835.77 Da) and B (5471.56 Da), and a peptide with a molecular mass of 3215.5 Da active only against Gram-negative indicator strains. The latter was unique in the databases. Enterococcus faecium GGN7 produces three bacteriocins with different inhibitory spectra. Based on its antimicrobial properties and safety, Ent. faecium GGN7 is potentially useful for food biopreservation. The results suggest the bacteriocins from GGN7 strain could be useful for food biopreservation. © 2014 The Society for Applied Microbiology.

Systematic analysis of snake neurotoxins' functional classification using a data warehousing approach.

Science.gov (United States)

Siew, Joyce Phui Yee; Khan, Asif M; Tan, Paul T J; Koh, Judice L Y; Seah, Seng Hong; Koo, Chuay Yeng; Chai, Siaw Ching; Armugam, Arunmozhiarasi; Brusic, Vladimir; Jeyaseelan, Kandiah

2004-12-12

Sequence annotations, functional and structural data on snake venom neurotoxins (svNTXs) are scattered across multiple databases and literature sources. Sequence annotations and structural data are available in the public molecular databases, while functional data are almost exclusively available in the published articles. There is a need for a specialized svNTXs database that contains NTX entries, which are organized, well annotated and classified in a systematic manner. We have systematically analyzed svNTXs and classified them using structure-function groups based on their structural, functional and phylogenetic properties. Using conserved motifs in each phylogenetic group, we built an intelligent module for the prediction of structural and functional properties of unknown NTXs. We also developed an annotation tool to aid the functional prediction of newly identified NTXs as an additional resource for the venom research community. We created a searchable online database of NTX proteins sequences (http://research.i2r.a-star.edu.sg/Templar/DB/snake_neurotoxin). This database can also be found under Swiss-Prot Toxin Annotation Project website (http://www.expasy.org/sprot/).

Induction of bacteriocin production by coculture is widespread among plantaricin-producing Lactobacillus plantarum strains with different regulatory operons.

Science.gov (United States)

Maldonado-Barragán, Antonio; Caballero-Guerrero, Belén; Lucena-Padrós, Helena; Ruiz-Barba, José Luis

2013-02-01

We describe the bacteriocin-production phenotype in a group of eight singular bacteriocinogenic Lactobacillus plantarum strains with three distinct genotypes regarding the plantaricin locus. Genotyping of these strains revealed the existence of two different plantaricin-production regulatory operons, plNC8-plNC8HK-plnD or plnABCD, involving three-component systems controlled each of them by a specific autoinducer peptide (AIP), i.e. PLNC8IF or PlnA. While all of the strains produced antimicrobial activity when growing on solid medium, most of them halted this production when cultured in broth, thus reflecting the functionality of regulatory mechanisms. Antimicrobial activity in broth cultures was re-established or enhanced when the specific AIP was added to the culture or by coculturing with specific bacterial strains. The latter trait appeared to be widespread in bacteriocinogenic L. plantarum strains independently of the regulatory system used to regulate bacteriocin production or the specific bacteriocins produced. The induction spectrum through coculture, i.e. the pattern of bacterial strains able to induce bacteriocin production, was characteristic of each individual L. plantarum strain. Also, the ability of some bacteria to induce bacteriocin production in L. plantarum by coculture appeared to be strain specific. The fact that induction of bacteriocin production by coculturing appeared to be a common feature in L. plantarum can be exploited accordingly to enhance the viability of this species in food and feed fermentations, as well as to contribute to probiotic functionality when colonising the gastrointestinal tract. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparative pathogenomics of Clostridium tetani.

Directory of Open Access Journals (Sweden)

Jonathan E Cohen

Full Text Available Clostridium tetani and Clostridium botulinum produce two of the most potent neurotoxins known, tetanus neurotoxin and botulinum neurotoxin, respectively. Extensive biochemical and genetic investigation has been devoted to identifying and characterizing various C. botulinum strains. Less effort has been focused on studying C. tetani likely because recently sequenced strains of C. tetani show much less genetic diversity than C. botulinum strains and because widespread vaccination efforts have reduced the public health threat from tetanus. Our aim was to acquire genomic data on the U.S. vaccine strain of C. tetani to better understand its genetic relationship to previously published genomic data from European vaccine strains. We performed high throughput genomic sequence analysis on two wild-type and two vaccine C. tetani strains. Comparative genomic analysis was performed using these and previously published genomic data for seven other C. tetani strains. Our analysis focused on single nucleotide polymorphisms (SNP and four distinct constituents of the mobile genome (mobilome: a hypervariable flagellar glycosylation island region, five conserved bacteriophage insertion regions, variations in three CRISPR (clustered regularly interspaced short palindromic repeats-Cas (CRISPR-associated systems, and a single plasmid. Intact type IA and IB CRISPR/Cas systems were within 10 of 11 strains. A type IIIA CRISPR/Cas system was present in two strains. Phage infection histories derived from CRISPR-Cas sequences indicate C. tetani encounters phages common among commensal gut bacteria and soil-borne organisms consistent with C. tetani distribution in nature. All vaccine strains form a clade distinct from currently sequenced wild type strains when considering variations in these mobile elements. SNP, flagellar glycosylation island, prophage content and CRISPR/Cas phylogenic histories provide tentative evidence suggesting vaccine and wild type strains share a

Comparative pathogenomics of Clostridium tetani.

Science.gov (United States)

Cohen, Jonathan E; Wang, Rong; Shen, Rong-Fong; Wu, Wells W; Keller, James E

2017-01-01

Clostridium tetani and Clostridium botulinum produce two of the most potent neurotoxins known, tetanus neurotoxin and botulinum neurotoxin, respectively. Extensive biochemical and genetic investigation has been devoted to identifying and characterizing various C. botulinum strains. Less effort has been focused on studying C. tetani likely because recently sequenced strains of C. tetani show much less genetic diversity than C. botulinum strains and because widespread vaccination efforts have reduced the public health threat from tetanus. Our aim was to acquire genomic data on the U.S. vaccine strain of C. tetani to better understand its genetic relationship to previously published genomic data from European vaccine strains. We performed high throughput genomic sequence analysis on two wild-type and two vaccine C. tetani strains. Comparative genomic analysis was performed using these and previously published genomic data for seven other C. tetani strains. Our analysis focused on single nucleotide polymorphisms (SNP) and four distinct constituents of the mobile genome (mobilome): a hypervariable flagellar glycosylation island region, five conserved bacteriophage insertion regions, variations in three CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems, and a single plasmid. Intact type IA and IB CRISPR/Cas systems were within 10 of 11 strains. A type IIIA CRISPR/Cas system was present in two strains. Phage infection histories derived from CRISPR-Cas sequences indicate C. tetani encounters phages common among commensal gut bacteria and soil-borne organisms consistent with C. tetani distribution in nature. All vaccine strains form a clade distinct from currently sequenced wild type strains when considering variations in these mobile elements. SNP, flagellar glycosylation island, prophage content and CRISPR/Cas phylogenic histories provide tentative evidence suggesting vaccine and wild type strains share a common ancestor.

Characterisation of inhibitory substances produced by two Pseudoalteromonas species and the cyanobacterial strain Flo1

OpenAIRE

Rau, Jan Erik

2011-01-01

In the present study the inhibitory substances of P. aurantia NCIMB 2052T and P. citrea NCIMB 1889T were investigated with respect to their substantial and functional nature, their inhibitory potential, their stability against various treatments as well as the growth phases and incubation conditions when the substances are produced. In addition, an inhibitory substance produced by strain Flo1 was examined regarding its structure, function, and inhibitory potential. Furthermore, its taxonomic ...

The hydrolytic enzymes produced by fungi strains isolated from the sand and soil of recreational areas

Science.gov (United States)

Kurnatowski, Piotr; Wójcik, Anna; Błaszkowska, Joanna; Góralska, Katarzyna

2016-10-01

The pathogenicity of fungi depends on, inter alia, the secretion of hydrolytic enzymes. The aim of this study was to determine the enzymatic activity of yeasts and yeast-like fungi isolated from children’s recreation areas, and compare the results with literature data of strains obtained from patients with mycoses. The enzymatic activity of 96 strains was assessed using an API ZYM kit (bioMerieux, France) and their biotypes were established. The fungal species were found to produce from 16 to 19 hydrolases: the most active were: leucine arylamidase (e5), acid phosphatase (e10), alkaline phosphatase (e1), naphthol-AS-BI-phosphohydrolase (e11), esterase – C4 (e2), β-galac - tosidase (e13) and β-glucosidase (e16). In addition, 13 biotypes characteristic of particular species of fungi were defined. Most strains could be categorized as biotypes C2 – 39.5% and A – 26%. The examined fungal strains isolated from recreational areas have selected biochemical characteristics i.e. production of hydrolases, which demonstrate their pathogenicity. They produce a number of enzymes which are also present in strains isolated from patients with mycoses, including: leucine arylamidase (e5), acid phosphatase (e10), naphthol-AS-BI-phosphohydrolase (e11) and alkaline phosphatase (e1). The biotypes identified in the course of this study (A, B3, B4, C1, C6 and D3) have been also reported in cases of fungal infection. Therefore, the fungi present in the sand and soil of recreational have pathogenic properties and are possible factors of fungal infection among children.

Cadophora malorum Cs-8-1 as a new fungal strain producing gibberellins isolated from Calystegia soldanella.

Science.gov (United States)

You, Young-Hyun; Yoon, Hyeokjun; Kang, Sang-Mo; Woo, Ju-Ri; Choo, Yeon-Sik; Lee, In-Jung; Shin, Jae-Ho; Kim, Jong-Guk

2013-07-01

Fourteen endophytic fungi with different colony morphologies were isolated from the roots of Calystegia soldanella. Endophytic fungi isolated from C. soldanella were identified by internal transcribed spacer (ITS) region. To verify plant growth promotion (PGP), culture filtrates of isolated endophytic fungi were treated in Waito-c rice (WR) and C. soldanella seedlings. Culture filtrates of Cs-8-1 fungal strain had advanced PGP activity. The presence of physiologically bioactive gibberellins (GA) GA(1) (1.213 ng ml(-1)), GA(3) (1.292 ng ml(-1)), GA(4) (3.6 ng ml(-1)), GA(7) (1.328 ng ml(-1)), other inactive GA(9) (0.796 ng ml(-1)) and GA(12) (0.417 ng ml(-1)), GA(20) (0.302 ng ml(-1)), GA(24) (1.351 ng ml(-1)), GA(34) (0.076 ng ml(-1)), and GA(53) (0.051 ng ml(-1)) in culture filtrates of Cs-8-1 fungal strain was detected. The Cs-8-1 fungal strain was confirmed as a producer of GAs. Molecular analysis of sequences showed high similarity of 99% to Cadophora malorum. Consequentially, the Cs-8-1 fungal strain was identified as a new C. malorum producing GAs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels.

Science.gov (United States)

Guan, Xuefang; Xu, Qingxian; Zheng, Yi; Qian, Lei; Lin, Bin

To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940) and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v) in simulated gastric juice (pH 2.5) for 2h and in simulated intestinal fluid (pH 8.0) for 3h. The auto-aggregation rate increased to 87.74% after 24h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Brevetoxin, the Dinoflagellate Neurotoxin, Localizes to Thylakoid Membranes and Interacts with the Light-Harvesting Complex II (LHCII) of Photosystem II.

Science.gov (United States)

Cassell, Ryan T; Chen, Wei; Thomas, Serge; Liu, Li; Rein, Kathleen S

2015-05-04

The brevetoxins are neurotoxins that are produced by the "Florida red tide" dinoflagellate Karenia brevis. They bind to and activate the voltage-gated sodium channels in higher organisms, specifically the Nav 1.4 and Nav 1.5 channel subtypes. However, the native physiological function that the brevetoxins perform for K. brevis is unknown. By using fluorescent and photoactivatable derivatives, brevetoxin was shown to localize to the chloroplast of K. brevis where it binds to the light-harvesting complex II (LHCII) and thioredoxin. The LHCII is essential to non-photochemical quenching (NPQ), whereas thioredoxins are critical to the maintenance of redox homeostasis within the chloroplast and contribute to the scavenging of reactive oxygen. A culture of K. brevis producing low levels of toxin was shown to be deficient in NPQ and produced reactive oxygen species at twice the rate of the toxic culture, implicating a role in NPQ for the brevetoxins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Clostridial constipation's broad pathology.

Science.gov (United States)

Johnson, S

2001-04-01

Clostridia are normally found in the healthy colon, where their numbers are kept in check by other bacteria. However, when they establish themselves in the ileum they become formidable foes. They produce medium-length fatty acids that increase water absorption, causing hypertension and drying up the feces, causing constipation.Furthermore, they can deconjugate bile (impaired fat absorption), metabolyze tryptophan (the most scarce of the essential amino acids), digest fiber (so that the more fiber the patient takes, the more the constipation is exacerbated), digest lecithin, produce carcinogenic metabolites and copious amounts of extremely foul smelling gas, etc. They can also prevent vitamin B12 absorption in the ileum, causing anemia. The synthetic sugar lactulose, which can only be digested by lactobacilli, can help displace the clostridia and resolve the constipation by causing the lactobacilli to produce short fatty acids that have the opposite effect to that of the medium fatty acids produced by clostridia and their accomplices: they cause water retention in the intestines. Copyright 2001 Harcourt Publishers Ltd.

Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

Directory of Open Access Journals (Sweden)

Oggero Roberto

2011-06-01

Full Text Available Abstract Background Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Results Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76 log10 vs 3.90 (2.50-7.10 CFU/g of faeces (p = 0.015. The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp.delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method, also in liquid co-cultures, thus demonstrating an antagonistic activity. Conclusions This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms

Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants.

Science.gov (United States)

Savino, Francesco; Cordisco, Lisa; Tarasco, Valentina; Locatelli, Emanuela; Di Gioia, Diana; Oggero, Roberto; Matteuzzi, Diego

2011-06-30

Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76) log10 vs 3.90 (2.50-7.10) CFU/g of faeces (p = 0.015). The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp. delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method), also in liquid co-cultures, thus demonstrating an antagonistic activity. This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms isolated from colicky infants. Our findings may stimulate

Comparison of Toxicological Properties of Botulinum Neurotoxin Serotypes A and B in Mice

Science.gov (United States)

Botulinum neurotoxins (BoNTs) are among the most toxic biological toxins for humans. Of the seven known serotypes (A-G) of BoNT, serotypes A, B and E cause most of the human foodborne intoxications. In this study, we compared the toxicological properties of BoNT serotype A and B holotoxins and compl...

Description of two Enterococcus strains isolated from traditional Peruvian artisanal-produced cheeses with a bacteriocin-like inhibitory activity

Directory of Open Access Journals (Sweden)

Aguilar Galvez A.

2009-01-01

Full Text Available The aim of this work was to isolate and to characterize strains of lactic acid bacteria (LAB with bacteriocin-like inhibitory activity from 27 traditional cheeses artisanal-produced obtained from different Peruvian regions. Twenty Gram+ and catalasenegative strains among 2,277 isolates exhibited bacteriocin-like inhibitory activity against Listeria monocytogenes CWBIB2232 as target strain. No change in inhibitory activity was observed after organic acid neutralization and treatment with catalase of the cell-free supernatant (CFS. The proteinic nature of the antimicrobial activity was confirmed for the twenty LAB strains by proteolytic digestion of the CFS. Two strains, CWBI-B1431 and CWBI-B1430, with the best antimicrobial activity were selected for further researches. These strains were taxonomically identified by phenotypic and genotypic analyses as Enterococcus mundtii (CWBI-B1431 and Enterococcus faecium (CWBI-B1430. The two strains were sensitive to vancomycin (MIC 2 μg.ml-1 and showed absence of haemolysis.

The screening of bacillus subtilis strain with high-produced antimicrobial substance using N+ ion implantation

International Nuclear Information System (INIS)

Shen Juan; Bie Xiaomei; Lu Zhaoxin; Lu Fengxia; Zhu Xiaoyu

2006-01-01

N + ion implantation was used to obtain higher-yield antimicrobial substance. Bacillus subtilis fmbJ was mutated by 25 keV N + ion implantation with the dose of 50 x 2.6 x 10 13 , 80 x 2.6 x 10 13 , 100 x 2.6 x 10 13 , 120 x 2.6 x 10 13 and 150 x 2.6 x 10 13 N + /m 2 . Results showed that the optimal N + ion dose was 50 x 2.6 x 10 13 N + /m 2 , and a strain of high-yield antimicrobials was obtained and named as Bacillus subtilis fmbJ224. Its antimicrobial substance yield was increased by 96% than the initial. The fermentation characteristic of the strain was studied, and the mode of producing antimicrobial substance for the selected strain was arrearage synthesis type. (authors)

Screening of biosurfactant-producing Bacillus strains using glycerol from the biodiesel synthesis as main carbon source.

Science.gov (United States)

Sousa, M; Melo, V M M; Rodrigues, S; Sant'ana, H B; Gonçalves, L R B

2012-08-01

Glycerol, a co-product of biodiesel production, was evaluated as carbon source for biosurfactant production. For this reason, seven non-pathogenic biosurfactant-producing Bacillus strains, isolated from the tank of chlorination at the Wastewater Treatment Plant at Federal University of Ceara, were screened. The production of biosurfactant was verified by determining the surface tension value, as well as the emulsifying capacity of the free-cell broth against soy oil, kerosene and N-hexadecane. Best results were achieved when using LAMI005 and LAMI009 strains, whose biosurfactant reduced the surface tension of the broth to 28.8 ± 0.0 and 27.1 ± 0.1 mN m(-1), respectively. Additionally, at 72 h of cultivation, 441.06 and 267.56 mg L(-1) of surfactin were produced by LAMI005 and LAMI009, respectively. The biosurfactants were capable of forming stable emulsions with various hydrocarbons, such as soy oil and kerosene. Analyses carried out with high performance liquid chromatography (HPLC) showed that the biosurfactant produced by Bacillus subtilis LAMI009 and LAMI005 was compatible with the commercially available surfactin standard. The values of minimum surface tension and the CMC of the produced biosurfactant indicated that it is feasible to produce biosurfactants from a residual and renewable and low-cost carbon source, such as glycerol.

Effect of cerulenin on fatty acid composition and gene expression pattern of DHA-producing strain Colwellia psychrerythraea strain 34H.

Science.gov (United States)

Wan, Xia; Peng, Yun-Feng; Zhou, Xue-Rong; Gong, Yang-Min; Huang, Feng-Hong; Moncalián, Gabriel

2016-02-06

Colwellia psychrerythraea 34H is a psychrophilic bacterium able to produce docosahexaenoic acid (DHA). Polyketide synthase pathway is assumed to be responsible for DHA production in marine bacteria. Five pfa genes from strain 34H were confirmed to be responsible for DHA formation by heterogeneous expression in Escherichia coli. The complexity of fatty acid profile of this strain was revealed by GC and GC-MS. Treatment of cells with cerulenin resulted in significantly reduced level of C16 monounsaturated fatty acid (C16:1(Δ9t), C16:1(Δ7)). In contrast, the amount of saturated fatty acids (C10:0, C12:0, C14:0), hydroxyl fatty acids (3-OH C10:0 and 3-OH C12:0), as well as C20:4ω3, C20:5ω3 and C22:6ω3 were increased. RNA sequencing (RNA-Seq) revealed the altered gene expression pattern when C. psychrerythraea cells were treated with cerulenin. Genes involved in polyketide synthase pathway and fatty acid biosynthesis pathway were not obviously affected by cerulenin treatment. In contrast, several genes involved in fatty acid degradation or β-oxidation pathway were dramatically reduced at the transcriptional level. Genes responsible for DHA formation in C. psychrerythraea was first cloned and characterized. We revealed the complexity of fatty acid profile in this DHA-producing strain. Cerulenin could substantially change the fatty acid composition by affecting the fatty acid degradation at transcriptional level. Acyl-CoA dehydrogenase gene family involved in the first step of β-oxidation pathway may be important to the selectivity of degraded fatty acids. In addition, inhibition of FabB protein by cerulenin may lead to the accumulation of malonyl-CoA, which is the substrate for DHA formation.

Using llama derived single domain antibodies to target botulinum neurotoxins

Science.gov (United States)

Swain, Marla D.; Anderson, George P.; Bernstein, Rachael D.; Liu, Jinny L.; Goldman, Ellen R.

2010-04-01

Llama serum contains both conventional IgG as well as unique forms of antibody that contain only heavy chains where antigen binding is mediated through a single variable domain. These variable domains can be expressed recombinantly and are referred to as single domain antibodies (sdAb). SdAb are among the smallest known naturally derived antigen binding fragments, possess good solubility, thermal stability, and can refold after heat and chemical denaturation. Llamas were immunized with either BoNT A or B toxoid and phage display libraries prepared. Single domain antibodies (sdAb) that were able to detect botulinum neurotoxin (BoNT) serotypes A and B were selected from their respective libraries. Here, the binders obtained by panning the BoNT B library on either BoNT B toxoid or BoNT B complex toxoid coated plates or BoNT B toxin coupled microspheres are described. Using these panning methods, we selected for binders that showed specificity for BoNT B. Phage displayed binders were screened, moved to a protein expression vector and soluble sdAb was produced. Using a Luminex flow cytometer binders were evaluated in direct binding assays. We have exploited the unique properties of sdAb and used them as biological recognition elements in immuno-based sensors that can detect BoNT B.

Bacterial Signaling to the Nervous System through Toxins and Metabolites.

Science.gov (United States)

Yang, Nicole J; Chiu, Isaac M

2017-03-10

Mammalian hosts interface intimately with commensal and pathogenic bacteria. It is increasingly clear that molecular interactions between the nervous system and microbes contribute to health and disease. Both commensal and pathogenic bacteria are capable of producing molecules that act on neurons and affect essential aspects of host physiology. Here we highlight several classes of physiologically important molecular interactions that occur between bacteria and the nervous system. First, clostridial neurotoxins block neurotransmission to or from neurons by targeting the SNARE complex, causing the characteristic paralyses of botulism and tetanus during bacterial infection. Second, peripheral sensory neurons-olfactory chemosensory neurons and nociceptor sensory neurons-detect bacterial toxins, formyl peptides, and lipopolysaccharides through distinct molecular mechanisms to elicit smell and pain. Bacteria also damage the central nervous system through toxins that target the brain during infection. Finally, the gut microbiota produces molecules that act on enteric neurons to influence gastrointestinal motility, and metabolites that stimulate the "gut-brain axis" to alter neural circuits, autonomic function, and higher-order brain function and behavior. Furthering the mechanistic and molecular understanding of how bacteria affect the nervous system may uncover potential strategies for modulating neural function and treating neurological diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Strain-Level Discrimination of Shiga Toxin-Producing Escherichia coli in Spinach Using Metagenomic Sequencing.

Directory of Open Access Journals (Sweden)

Susan R Leonard

Full Text Available Consumption of fresh bagged spinach contaminated with Shiga toxin-producing Escherichia coli (STEC has led to severe illness and death; however current culture-based methods to detect foodborne STEC are time consuming. Since not all STEC strains are considered pathogenic to humans, it is crucial to incorporate virulence characterization of STEC in the detection method. In this study, we assess the comprehensiveness of utilizing a shotgun metagenomics approach for detection and strain-level identification by spiking spinach with a variety of genomically disparate STEC strains at a low contamination level of 0.1 CFU/g. Molecular serotyping, virulence gene characterization, microbial community analysis, and E. coli core gene single nucleotide polymorphism (SNP analysis were performed on metagenomic sequence data from enriched samples. It was determined from bacterial community analysis that E. coli, which was classified at the phylogroup level, was a major component of the population in most samples. However, in over half the samples, molecular serotyping revealed the presence of indigenous E. coli which also contributed to the percent abundance of E. coli. Despite the presence of additional E. coli strains, the serotype and virulence genes of the spiked STEC, including correct Shiga toxin subtype, were detected in 94% of the samples with a total number of reads per sample averaging 2.4 million. Variation in STEC abundance and/or detection was observed in replicate spiked samples, indicating an effect from the indigenous microbiota during enrichment. SNP analysis of the metagenomic data correctly placed the spiked STEC in a phylogeny of related strains in cases where the indigenous E. coli did not predominate in the enriched sample. Also, for these samples, our analysis demonstrates that strain-level phylogenetic resolution is possible using shotgun metagenomic data for determining the genomic relatedness of a contaminating STEC strain to other

Maculotoxin: a neurotoxin from the venom glands of the octopus Hapalochlaena maculosa identified as tetrodotoxin.

Science.gov (United States)

Sheumack, D D; Howden, M E; Spence, I; Quinn, R J

1978-01-13

Maculotoxin, a potent neurotoxin isolated from the posterior salivary glands of the blue-ringed octopus. Hapalochlaena maculosa, has now been identified as tetrodotoxin. This is the first reported case in which tetrodotoxin has been found to occur in a venom.

Prevalence and clonal relationship of ESBL-producing Salmonella strains from humans and poultry in northeastern Algeria.

Science.gov (United States)

Djeffal, Samia; Bakour, Sofiane; Mamache, Bakir; Elgroud, Rachid; Agabou, Amir; Chabou, Selma; Hireche, Sana; Bouaziz, Omar; Rahal, Kheira; Rolain, Jean-Marc

2017-05-15

The aims of this study were to investigate Salmonella contamination in broiler chicken farms and slaughterhouses, to assess the antibiotic resistance profile in avian and human Salmonella isolates, and to evaluate the relationship between avian and human Extended Spectrum β-Lactamase (ESBL)-producing isolates. Salmonella was screened in different sample matrices collected at thirty-two chicken farms and five slaughterhouses. The human isolates were recovered from clinical specimens at the University Teaching Hospital of Constantine (UTH). All suspected colonies were confirmed by MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time OF light) and serotyped. Susceptibility testing against 13 antibiotics including, amoxicillin/clavulanic acid, ticarcillin, cefoxitin, cefotaxime, aztreonam, imipenem, ertapenem, gentamicin, amikacin, ciprofloxacin, colistin, trimethoprim/sulfamethoxazole and fosfomycin, was performed using the disk diffusion method on Mueller-Hinton agar. ESBL-production was screened by the double-disk synergy test and confirmed by molecular characterization using PCR (polymerase chain reaction) amplification and sequencing of ESBL encoding genes. Clonality of the avian and human strains was performed using the Multi Locus Sequencing Typing method (MLST). Forty-five isolated avian Salmonella strains and 37 human collected ones were studied. Five S. enterica serotypes were found in avian isolates (mainly Kentucky) and 9 from human ones (essentially Infantis). 51.11% and 26.6% of the avian isolates were resistant to ciprofloxacin and cefotaxime, respectively, whereas human isolates were less resistant to these antibiotics (13.5% to ciprofloxacin and 16.2% to cefotaxime). Eighteen (12 avian and 6 human) strains were found to produce ESBLs, which were identified as bla CTX-M-1 (n = 12), bla CTX-M-15 (n = 5) and bla TEM group (n = 8). Interestingly, seven of the ESBL-producing strains (5 avian and 2 human) were of the same ST (ST15) and

Irradiation studies of local Streptomyces strains for higher antibiotic producing capacity. Part of a coordinated programme on radiation microbiology

International Nuclear Information System (INIS)

Kintanar, Q.L.

1978-06-01

The 14 mutants produced by sequential exposure to gamma and ultraviolet irradiation were found to belong to different fundamental types of variants differing in morphology, stability, and metabolite spectra from the parent strain. The first hour mutants, M-1 to M-4 could be considered as belonging to the first category of mutants. Metabolites produced were the same as the parent but differ only in quantity. One was a morphological mutant, M-4 which differed from the parent strain in the production of a brown pigment and conidia, and lack of aerial mycelium. It was found to be most stable and capable of producing high antibiotic yield. The rest of the mutants, M-5 to M-14 could be grouped in the second category. The synthesis of one or more metabolites of the parent strain has been lost by mutation. Unexpectedly, a mutant, M-9 instead of synthesizing either oxytetracycline or tetracycline produced chlortetracycline. Coconut water was found inhibitory to the production of antibiotics by the parent strain and the high and low producing mutants. Modifying the medium by incorporating phosphate and adjusting the initial pH to 4.75 raised the antibiotic yield of the 10% coconut water supplemented medium of M-4 more than the control. Higher pH than the optimum shortened the lag phase but reduced the antibiotic yield while a lower initial pH prevented the growth of the organism giving negligible yield. A reduction of pH to pH 4.5 for the initial 48 hours lengthened the lag phase with almost no adverse effect on the yield. The incorporation of large amounts of coconut water aggravated the amino acid imbalance of the medium

Techno-functional differentiation of two vitamin B12 producing Lactobacillus plantarum strains: an elucidation for diverse future use.

Science.gov (United States)

Bhushan, Bharat; Tomar, S K; Chauhan, Arun

2017-01-01

An appropriate selection of Lactobacillus strain (probiotic/starter/functional) on the basis of its techno-functional characteristics is required before developing a novel fermented functional food. We compared vitamin B 12 (B 12 , cobalamin) producing Lactobacillus plantarum isolates, BHM10 and BCF20, for functional (vitamin over-production, genomic insight to B 12 structural genes, and probiotic attributes) and technological [milks (skim and soy) fermentation and B 12 bio-fortification] characteristics. Addition of B 12 precursors (5-amonolevulinate and dimethylbenzimidazole) to cobalamin-free fermentation medium increased vitamin production in BHM10, BCF20, and DSM20016 (a positive standard) by 3.4-, 4.4-, and 3.86-folds, respectively. Three important B 12 structural genes were detected in L. plantarum species (strains BHM10 and BCF20) by PCR for the first time. The gene sequences were submitted to NCBI GenBank and found phylogenetically closer to respective sequences in B 12 producing Lactobacillus reuteri strains. During comparative probiotic testing, BCF20 showed significantly higher (p < 0.05 to p < 0.001) gastrointestinal tolerance and cell surface hydrophobicity (p < 0.05) than BHM10. Moreover, only BCF20 was found positive for BSH activity and also exhibited comparatively better antagonistic potential against potent pathogens. Conversely, high acid and bile susceptible strain BHM10 displayed significantly higher soy milk fermentation and resultant B 12 bio-fortification abilities during technological testing. Two B 12 quantification techniques, UFLC and competitive immunoassay, confirmed the in vitro and in situ bio-production of bio-available form of B 12 after BHM10 fermentation. Conclusively, techno-functional differentiation of two B 12 producing strains elucidates their diverse future use; BCF20 either for B 12 over-production (in vitro) or as a probiotic candidate, while BHM10 for cobalamin bio-fortification (in situ) in soy milk.

Neuronal targeting, internalization, and biological activity of a recombinant atoxic derivative of botulinum neurotoxin A

Science.gov (United States)

Botulinum neurotoxins (BoNT) have the unique capacity to cross epithelial barriers, target neuromuscular junctions, and translocate active metalloprotease component to the cytosol of motor neurons. We have taken advantage of the molecular carriers responsible for this trafficking to create a family ...

Biological characterization of lead-enhanced exopolysaccharide produced by a lead resistant Enterobacter cloacae strain P2B.

Science.gov (United States)

Naik, Milind Mohan; Pandey, Anju; Dubey, Santosh Kumar

2012-09-01

A lead resistant bacterial strain isolated from effluent of lead battery manufacturing company of Goa, India has been identified as Enterobacter cloacae strain P2B based on morphological, biochemical characters, FAME profile and 16S rDNA sequence data. This bacterial strain could resist lead nitrate up to 1.6 mM. Significant increase in exopolysaccharide (EPS) production was observed as the production increased from 28 to 108 mg/L dry weight when exposed to 1.6 mM lead nitrate in Tris buffered minimal medium. Fourier-transformed infrared spectroscopy of this EPS revealed presence of several functional groups involved in metal binding viz. carboxyl, hydroxyl and amide groups along with glucuronic acid. Gas chromatography coupled with mass spectrometry analysis of alditol-acetate derivatives of acid hydrolysed EPS produced in presence of 1.6 mM lead nitrate demonstrated presence of several neutral sugars such as rhamnose, arabinose, xylose, mannose, galactose and glucose, which contribute to lead binding hydroxyl groups. Scanning electron microscope coupled with energy dispersive X-ray spectrometric analysis of this lead resistant strain exposed to 1.6 mM lead nitrate interestingly revealed mucous EPS surrounding bacterial cells which sequestered 17 % lead (as weight %) extracellularly and protected the bacterial cells from toxic effects of lead. This lead resistant strain also showed multidrug resistance. Thus these results significantly contribute to better understanding of structure, function and environmental application of lead-enhanced EPSs produced by bacteria. This lead-enhanced biopolymer can play a very important role in bioremediation of several heavy metals including lead.

Co-expression Network Approach to Studying the Effects of Botulinum Neurotoxin-A.

Science.gov (United States)

Mukund, Kavitha; Ward, Samuel R; Lieber, Richard L; Subramaniam, Shankar

2017-10-16

Botulinum Neurotoxin A (BoNT-A) is a potent neurotoxin with several clinical applications.The goal of this study was to utilize co-expression network theory to analyze temporal transcriptional data from skeletal muscle after BoNT-A treatment. Expression data for 2000 genes (extracted using a ranking heuristic) served as the basis for this analysis. Using weighted gene co-expression network analysis (WGCNA), we identified 19 co-expressed modules, further hierarchically clustered into 5 groups. Quantifying average expression and co-expression patterns across these groups revealed temporal aspects of muscle's response to BoNT-A. Functional analysis revealed enrichment of group 1 with metabolism; group 5 with contradictory functions of atrophy and cellular recovery; and groups 2 and 3 with extracellular matrix (ECM) and non-fast fiber isoforms. Topological positioning of two highly ranked, significantly expressed genes- Dclk1 and Ostalpha within group 5 suggested possible mechanistic roles in recovery from BoNT-A induced atrophy. Phenotypic correlations of groups with titin and myosin protein content further emphasized the effect of BoNT-A on the sarcomeric contraction machinery in early phase of chemodenervation. In summary, our approach revealed a hierarchical functional response to BoNT-A induced paralysis with early metabolic and later ECM responses and identified putative biomarkers associated with chemodenervation. Additionally, our results provide an unbiased validation of the response documented in our previous workBotulinum Neurotoxin A (BoNT-A) is a potent neurotoxin with several clinical applications.The goal of this study was to utilize co-expression network theory to analyze temporal transcriptional data from skeletal muscle after BoNT-A treatment. Expression data for 2000 genes (extracted using a ranking heuristic) served as the basis for this analysis. Using weighted gene co-expression network analysis (WGCNA), we identified 19 co-expressed modules

[Antagonism against Beauveria bassiana by lipopeptide metabolites produced by entophyte Bacillus amyloliquefaciens strain SWB16].

Science.gov (United States)

Wang, Jingjie; Zhao, Dongyang; Liu, Yonggui; Ao, Xiang; Fan, Rui; Duan, Zhengqiao; Liu, Yanping; Chen, Qianqian; Jin, Zhixiong; Wan, Yongji

2014-07-04

We screened bacterial strains that have strong antagonism against Beauveria bassiana, an important pathogen of silkworm industry, and detected the antagonistic activity of lipopeptide metabolites. We identified bacterium SWB16 by morphological observation, physiological and biochemical experiments, 16SrRNA, and gyrA gene sequence analysis, tested antagonistic activity of strain SWB16 against Beauveria bassiana by measuring the inhibition zone diameter using filter paper diffusion method (Kirby-Bauer method), obtained lipopeptide metabolites of the strain using methanol extraction and observed the antagonism of strain SWB16 lipopeptide extracts against the conidia and hyphae of Beauveria bassiana, detected main ingredients and genes of lipopeptide metabolites by high-performance liquid chromatography-mass spectrometry and PCR amplification. SWB16 isolated from tissue of plant Dioscorea zingiberensis C. H. Wright belongs to Bacillus amyloliquefaciens and showed high antagonistic activity to Beauveria bassiana, and the lipopeptide extracts of isolate SWB16 exhibited significant inhibition to conidial germination and mycelial growth of Beauveria bassiana. The result of mass spectrometric detection indicated main component of the lipopeptide metabolites were fengcin and iturin, and genes fenB, ituA involved in the synthesis of them were amplified in the genome. Bacillus amyloliquefaciens strain SWB16 could produce lipopeptide antibiotics with strong antagonism to the entomopathogenic fungus Beauveria bassiana, and the results suggested that strain SWB16 has potential application value for controlling white muscardine of economic insects including silkworm.

Isolation of a yeast strain able to produce a polygalacturonase with maceration activity of cassava roots

Directory of Open Access Journals (Sweden)

María Alicia Martos

2013-06-01

Full Text Available The objective of the present study was the isolation of a yeast strain, from citrus fruit peels, able to produce a polygalacturonase by submerged fermentation with maceration activity of raw cassava roots. Among 160 yeast strains isolated from citrus peels, one strain exhibited the strongest pectinolytic activity. This yeast was identified as Wickerhamomyces anomalus by 5.8S-ITS RFLP analysis and confirmed by amplification of the nucleotide sequence. The yeast produced a polygalacturonase (PG in Erlenmeyer shake flasks containing YNB, glucose, and citrus pectin. PG synthesis occurred during exponential growth phase, reaching 51 UE.mL-1 after 8 hours of fermentation. A growth yield (Yx/s of 0.43 gram of cell dry weight per gram of glucose consumed was obtained, and a maximal specific growth rate (µm of 0.346 h-1 was calculated. The microorganism was unable to assimilate sucrose, galacturonic acid, polygalacturonic acid, or citrus pectin, but it required glucose as carbon and energy source and polygalacturonic acid or citrus pectin as inducers of enzyme synthesis. The crude enzymatic extract of Wickerhamomyces anomalus showed macerating activity of raw cassava. This property is very important in the production of dehydrated mashed cassava, a product of regional interest in the province of Misiones, Argentina.

Saxitoxin - neurotoxin produkovaný sinicemi v povrchových vodách České republiky

Czech Academy of Sciences Publication Activity Database

Jančula, Daniel; Babica, Pavel; Straková, Lucie; Sadílek, Jan; Maršálek, Blahoslav

2013-01-01

Roč. 63, č. 12 (2013), s. 406-409 ISSN 1211-0760 Grant - others:European Commission(XE) FP/2007-2013 no.2SGA2858 Institutional support: RVO:67985939 Keywords : cyanobacterial toxins * neurotoxin * hazard Subject RIV: EF - Botanics

Draft Genome Sequence of Lactobacillus delbrueckii subsp. bulgaricus CRL871, a Folate-Producing Strain Isolated from a Northwestern Argentinian Yogurt.

Science.gov (United States)

Laiño, Jonathan Emiliano; Hebert, Elvira María; Savoy de Giori, Graciela; LeBlanc, Jean Guy

2015-06-25

Lactobacillus delbrueckii subsp. bulgaricus CRL871 is the first strain of L. delbrueckii subsp. bulgaricus reported as a folate-producing strain. We report the draft genome sequence of L. delbrueckii subsp. bulgaricus CRL871 (2,063,981 bp, G+C content of 49.1%). This strain is of great biotechnological importance to the dairy industry because it constitutes an alternative to folic acid fortification. Copyright © 2015 Laiño et al.

New Typical Vector of Neurotoxin β-N-Methylamino-l-Alanine (BMAA in the Marine Benthic Ecosystem

Directory of Open Access Journals (Sweden)

Aifeng Li

2016-11-01

Full Text Available The neurotoxin β-N-methylamino-l-alanine (BMAA has been identified as an environmental factor triggering neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS and Alzheimer’s disease (AD. We investigated the possible vectors of BMAA and its isomers 2,4-diaminobutyric acid (DAB and N-2(aminoethylglycine (AEG in marine mollusks collected from the Chinese coast. Sixty-eight samples of marine mollusks were collected along the Chinese coast in 2016, and were analyzed by an HILIC-MS/MS (hydrophilic interaction liquid chromatography with tandem quadrupole mass spectrometer method without derivatization. BMAA was detected in a total of five samples from three species: Neverita didyma, Solen strictus, and Mytilus coruscus. The top three concentrations of free-form BMAA (0.99~3.97 μg·g−1 wet weight were detected in N. didyma. DAB was universally detected in most of the mollusk samples (53/68 with no species-specific or regional differences (0.051~2.65 μg·g−1 wet weight. No AEG was detected in any mollusk samples tested here. The results indicate that the gastropod N. didyma might be an important vector of the neurotoxin BMAA in the Chinese marine ecosystem. The neurotoxin DAB was universally present in marine bivalve and gastropod mollusks. Since N. didyma is consumed by humans, we suggest that the origin and risk of BMAA and DAB toxins in the marine ecosystem should be further investigated in the future.

Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.

Directory of Open Access Journals (Sweden)

Maqshoof Ahmad

2013-12-01

Full Text Available Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

Physicochemical properties and membrane biofouling of extra-cellular polysaccharide produced by a Micrococcus luteus strain.

Science.gov (United States)

Feng, Lei; Li, Xiufen; Song, Ping; Du, Guocheng; Chen, Jian

2014-07-01

The physicochemical properties of the extra-cellular polysaccharide (EPS) produced by a Micrococcus luteus strain, a dominating strain isolated from membrane biofouling layer, were determined in this study. The EPS isolated from this strain was measured to have an average molecular weight of 63,540 Da and some typical polysaccharide absorption peaks in Fourier transform infrared spectrum. Monosaccharide components of the EPS contained rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose in a molar ratio of 0.2074:0.0454:0.0262:0.0446:1.7942:1.2086:0.4578. Pseudo plastic properties were also observed for the EPS through the rheological measurement. The EPS was further characterized for its behavior to cause membrane flux decline. The results showed that both flux declines for polyvinylidenefluoride (PVDF) and polypropylene membranes became more severe as EPS feed concentration increased. A higher irreversible fouling for the PVDF membrane suggested that the EPS had the larger fouling potential to this microfiltration membrane.

Atypical patterns of neural infection produced in mice by drug-resistant strains of herpes simplex virus.

Science.gov (United States)

Field, H J; Anderson, J R; Wildy, P

1982-03-01

Mice inoculated intracerebrally (i.c.) with a mutant strain of HSV were found to develop cataracts 1 to 2 months after inoculation. Cataract formation was subsequently shown to follow an acute retinitis which commenced within 1 week of inoculation. The mutant had been selected for high resistance to the nucleoside analogue acyclovir and has been shown previously to be defective in the induction of thymidine kinase and also to express an altered DNA polymerase. The LD50 for mice inoculated i.c. was greater than 10(5) p.f.u. compared with approx 7 p.f.u. for the parental strain. Studies of virus replication following i.c. inoculation with a sublethal dose of the mutant revealed that only small amounts of infectious virus were produced in the brain, but during a period from 6 to 12 days after inoculation vigorous replication occurred in retinal tissue, producing very high titres of virus.

Structure of an extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83

Energy Technology Data Exchange (ETDEWEB)

Vanhaverbeke, C.; Bosso, C.; Colin-Morel, P.; Gey, C.; Heyraud, A. [Centre de Recherches sur les Macromolecules Vegetales, CNRS and Universite Joseph Fourier, B.P.53, F-38041 Grenoble (France); Gamar-Nourani, L.; Blondeau, K.; Simonet, J.-M. [Institut de Genetique et Microbiologie, Laboratoire de Genetique Moleculaire des Bacteries d' Interet Industriel, CNRS URA 2225, Batiment 360, Universite de Paris Sud, F-91405 Orsay (France)

1998-12-31

The extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83 was found to be composed of d-glucose and d-galactose in a molar ratio of 2:3. The primary structure of the polysaccharide was shown by sugar analysis, methylation analysis, FABMS, partial acid hydrolysis and nuclear magnetic resonance (NMR) spectroscopy to consist of a pentasaccharide repeating unit having the following structure:-3)-{alpha}-d-Glcp-(1-2)-{beta}-d-Galf-(1-6)-{alpha}-d-Galp-(1-6) -{alpha}-d-Glcp-(1-3)-{beta}-d-Galf-(1-. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Structure of an extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83

International Nuclear Information System (INIS)

Vanhaverbeke, C.; Bosso, C.; Colin-Morel, P.; Gey, C.; Heyraud, A.; Gamar-Nourani, L.; Blondeau, K.; Simonet, J.-M.

1998-01-01

The extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83 was found to be composed of d-glucose and d-galactose in a molar ratio of 2:3. The primary structure of the polysaccharide was shown by sugar analysis, methylation analysis, FABMS, partial acid hydrolysis and nuclear magnetic resonance (NMR) spectroscopy to consist of a pentasaccharide repeating unit having the following structure:-3)-α-d-Glcp-(1-2)-β-d-Galf-(1-6)-α-d-Galp-(1-6) -α-d-Glcp-(1-3)-β-d-Galf-(1-. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Botulinum Neurotoxins and Botulism: A Novel Therapeutic Approach

Directory of Open Access Journals (Sweden)

Wanpen Chaicumpa

2011-05-01

Full Text Available Specific treatment is not available for human botulism. Current remedial mainstay is the passive administration of polyclonal antibody to botulinum neurotoxin (BoNT derived from heterologous species (immunized animal or mouse hybridoma together with supportive and symptomatic management. The antibody works extracellularly, probably by blocking the binding of receptor binding (R domain to the neuronal receptors; thus inhibiting cellular entry of the holo-BoNT. The antibody cannot neutralize the intracellular toxin. Moreover, a conventional antibody with relatively large molecular size (150 kDa is not accessible to the enzymatic groove and, thus, cannot directly inhibit the BoNT zinc metalloprotease activity. Recently, a 15–20 kDa single domain antibody (VHH that binds specifically to light chain of BoNT serotype A was produced from a humanized-camel VH/VHH phage display library. The VHH has high sequence homology (>80% to the human VH and could block the enzymatic activity of the BoNT. Molecular docking revealed not only the interface binding between the VHH and the toxin but also an insertion of the VHH CDR3 into the toxin enzymatic pocket. It is envisaged that, by molecular linking the VHH to a cell penetrating peptide (CPP, the CPP-VHH fusion protein would be able to traverse the hydrophobic cell membrane into the cytoplasm and inhibit the intracellular BoNT. This presents a novel and safe immunotherapeutic strategy for botulism by using a cell penetrating, humanized-single domain antibody that inhibits the BoNT by means of a direct blockade of the groove of the menace enzyme.

Ultrasound Guidance for Botulinum Neurotoxin Chemodenervation Procedures

Directory of Open Access Journals (Sweden)

Katharine E. Alter

2017-12-01

Full Text Available Injections of botulinum neurotoxins (BoNTs are prescribed by clinicians for a variety of disorders that cause over-activity of muscles; glands; pain and other structures. Accurately targeting the structure for injection is one of the principle goals when performing BoNTs procedures. Traditionally; injections have been guided by anatomic landmarks; palpation; range of motion; electromyography or electrical stimulation. Ultrasound (US based imaging based guidance overcomes some of the limitations of traditional techniques. US and/or US combined with traditional guidance techniques is utilized and or recommended by many expert clinicians; authors and in practice guidelines by professional academies. This article reviews the advantages and disadvantages of available guidance techniques including US as well as technical aspects of US guidance and a focused literature review related to US guidance for chemodenervation procedures including BoNTs injection.

Isolation and characterization of biosurfactant-producing Alcanivorax strains: hydrocarbon accession strategies and alkane hydroxylase gene analysis.

Science.gov (United States)

Olivera, Nelda L; Nievas, Marina L; Lozada, Mariana; Del Prado, Guillermo; Dionisi, Hebe M; Siñeriz, Faustino

2009-01-01

Biosurfactant-producing bacteria belonging to the genera Alcanivorax, Cobetia and Halomonas were isolated from marine sediments with a history of hydrocarbon exposure (Aristizábal and Gravina Peninsulas, Argentina). Two Alcanivorax isolates were found to form naturally occurring consortia with strains closely related to Pseudomonas putida and Microbacterium esteraromaticum. Alkane hydroxylase gene analysis in these two Alcanivorax strains resulted in the identification of two novel alkB genes, showing 86% and 60% deduced amino acid sequence identity with those of Alcanivorax sp. A-11-3 and Alcanivorax dieselolei P40, respectively. In addition, a gene homologous to alkB2 from Alcanivorax borkumensis was present in one of the strains. The consortium formed by this strain, Alcanivorax sp. PA2 (98.9% 16S rRNA gene sequence identity with A. borkumensis SK2(T)) and P. putida PA1 was characterized in detail. These strains form cell aggregates when growing as mixed culture, though only PA2 was responsible for biosurfactant activity. During exponential growth phase of PA2, cells showed high hydrophobicity and adherence to hydrocarbon droplets. Biosurfactant production was only detectable at late growth and stationary phases, suggesting that it is not involved in initiating oil degradation and that direct interfacial adhesion is the main hydrocarbon accession mode of PA2. This strain could be useful for biotechnological applications due to its biosurfactant production, catabolic and aggregation properties.

Increased levels of SV2A botulinum neurotoxin receptor in clinical sensory disorders and functional effects of botulinum toxins A and E in cultured human sensory neurons

Directory of Open Access Journals (Sweden)

Yiangou Y

2011-10-01

Full Text Available Yiangos Yiangou1 Uma Anand1,2, William R. Otto2, Marco Sinisi3, Michael Fox3, Rolfe Birch3 Keith A. Foster4, Gaurav Mukerji1,5, Ayesha Akbar1,6, Sanjiv K. Agarwal5, Praveen Anand11Department of Clinical Neuroscience, Imperial College London, Hammersmith Hospital, London; 2Histopathology Laboratory, Cancer Research UK, London Research Institute, London; 3Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Stanmore; 4Syntaxin Ltd, Oxford; 5Department of Urology; 6Department of Gastroenterology, Imperial College London, Hammersmith Hospital, London, United Kingdom Background: There is increasing evidence that botulinum neurotoxin A may affect sensory nociceptor fibers, but the expression of its receptors in clinical pain states, and its effects in human sensory neurons, are largely unknown.Methods: We studied synaptic vesicle protein subtype SV2A, a receptor for botulinum neurotoxin A, by immunostaining in a range of clinical tissues, including human dorsal root ganglion sensory neurons, peripheral nerves, the urinary bladder, and the colon. We also determined the effects of botulinum neurotoxins A and E on localization of the capsaicin receptor, TRPV1, and functional sensitivity to capsaicin stimuli in cultured human dorsal root ganglion neurons.Results: Image analysis showed that SV2A immunoreactive nerve fibers were increased in injured nerves proximal to the injury (P = 0.002, and in painful neuromas (P = 0.0027; the ratio of percentage area SV2A to neurofilaments (a structural marker was increased proximal to injury (P = 0.0022 and in neuromas (P = 0.0001, indicating increased SV2A levels in injured nerve fibers. In the urinary bladder, SV2A nerve fibers were found in detrusor muscle and associated with blood vessels, with a significant increase in idiopathic detrusor overactivity (P = 0.002 and painful bladder syndrome (P = 0.0087. Colon biopsies showed numerous SV2A-positive nerve fibers, which were increased in quiescent

Structural basis for recognition of synaptic vesicle protein 2C by botulinum neurotoxin A

NARCIS (Netherlands)

Benoit, Roger M.; Frey, Daniel; Hilbert, Manuel; Kevenaar, Josta T.|info:eu-repo/dai/nl/338771042; Wieser, Mara M.; Stirnimann, Christian U.; McMillan, David; Ceska, Tom; Lebon, Florence; Jaussi, Rolf; Steinmetz, Michel O.; Schertler, Gebhard F X; Hoogenraad, Casper C.|info:eu-repo/dai/nl/227263502; Capitani, Guido; Kammerer, Richard A.

2014-01-01

Botulinum neurotoxin A (BoNT/A) belongs to the most dangerous class of bioweapons. Despite this, BoNT/A is used to treat a wide range of common medical conditions such as migraines and a variety of ocular motility and movement disorders. BoNT/A is probably best known for its use as an antiwrinkle

Intra-operative ultrasound hand-held strain imaging for the visualization of ablations produced in the liver with a toroidal HIFU transducer: first in vivo results

Energy Technology Data Exchange (ETDEWEB)

Chenot, J; Melodelima, D; N' Djin, W A; Souchon, Remi; Rivoire, M; Chapelon, J Y, E-mail: jeremy.chenot@inserm.f [Inserm, U556, Lyon, F-69003 (France)

2010-06-07

The use of hand-held ultrasound strain imaging for the intra-operative real-time visualization of HIFU (high-intensity focused ultrasound) ablations produced in the liver by a toroidal transducer was investigated. A linear 12 MHz ultrasound imaging probe was used to obtain radiofrequency signals. Using a fast cross-correlation algorithm, strain images were calculated and displayed at 60 frames s{sup -1}, allowing the use of hand-held strain imaging intra-operatively. Fourteen HIFU lesions were produced in four pigs. Intra-operative strain imaging of HIFU ablations in the liver was feasible owing to the high frame rate. The correlation between dimensions measured on gross pathology and dimensions measured on B-mode images and on strain images were R = 0.72 and R = 0.94 respectively. The contrast between ablated and non-ablated tissue was significantly higher (p < 0.05) in the strain images (22 dB) than in the B-mode images (9 dB). Strain images allowed equivalent or improved definition of ablated regions when compared with B-mode images. Real-time intra-operative hand-held strain imaging seems to be a promising complement to conventional B-mode imaging for the guidance of HIFU ablations produced in the liver during an open procedure. These results support that hand-held strain imaging outperforms conventional B-mode ultrasound and could potentially be used for the assessment of thermal therapies.

Pathway Construction in Corynebacterium glutamicum and Strain Engineering To Produce Rare Sugars from Glycerol.

Science.gov (United States)

Yang, Jiangang; Zhu, Yueming; Men, Yan; Sun, Shangshang; Zeng, Yan; Zhang, Ying; Sun, Yuanxia; Ma, Yanhe

2016-12-21

Rare sugars are valuable natural products widely used in pharmaceutical and food industries. In this study, we expected to synthesize rare ketoses from abundant glycerol using dihydroxyacetone phosphate (DHAP)-dependent aldolases. First, a new glycerol assimilation pathway was constructed to synthesize DHAP. The enzymes which convert glycerol to 3-hydroxypropionaldehyde and l-glyceraldehyde were selected, and their corresponding aldehyde synthesis pathways were constructed in vivo. Four aldol pathways based on different aldolases and phosphorylase were gathered. Next, three pathways were assembled and the resulting strains synthesized 5-deoxypsicose, 5-deoxysorbose, and 5-deoxyfructose from glucose and glycerol and produce l-fructose, l-tagatose, l-sorbose, and l-psicose with glycerol as the only carbon source. To achieve higher product titer and yield, the recombinant strains were further engineered and fermentation conditions were optimized. Fed-batch culture of engineered strains obtained 38.1 g/L 5-deoxypsicose with a yield of 0.91 ± 0.04 mol product per mol of glycerol and synthesized 20.8 g/L l-fructose, 10.3 g/L l-tagatose, 1.2 g/L l-sorbose, and 0.95 g/L l-psicose.

Explaining human recreational use of 'pesticides': The neurotoxin regulation model of substance use vs. the hijack model and implications for age and sex differences in drug consumption

Directory of Open Access Journals (Sweden)

Edward H Hagen

2013-11-01

Full Text Available Most globally popular drugs are plant neurotoxins or their close chemical analogs. These compounds evolved to deter, not reward or reinforce, consumption. Moreover, they reliably activate virtually all toxin defense mechanisms, and are thus correctly identified by human neurophysiology as toxins. Acute drug toxicity must therefore play a more central role in drug use theory. We accordingly challenge the popular idea that the rewarding and reinforcing properties of drugs "hijack" the brain, and propose instead that the brain evolved to carefully regulate neurotoxin consumption to minimize fitness costs and maximize fitness benefits. This perspective provides a compelling explanation for the dramatic changes in substance use that occur during the transition from childhood to adulthood, and for pervasive sex differences in substance use: because nicotine and many other plant neurotoxins are teratogenic, children, and to a lesser extent women of childbearing age, evolved to avoid ingesting them. However, during the course of human evolution many adolescents and adults reaped net benefits from regulated intake of plant neurotoxins.

A comparative study on three analytical methods for the determination of the neurotoxin BMAA in cyanobacteria

NARCIS (Netherlands)

Faassen, E.J.; Gillissen, F.; Lurling, M.

2012-01-01

The cyanobacterial neurotoxin ß-N-methylamino-L-alanine (BMAA) has been considered a serious health threat because of its putative role in multiple neurodegenerative diseases. First reports on BMAA concentrations in cyanobacteria were alarming: nearly all cyanobacteria were assumed to contain high

Differential role of molten globule and protein folding in distinguishing unique features of botulinum neurotoxin.

Science.gov (United States)

Kumar, Raj; Kukreja, Roshan V; Cai, Shuowei; Singh, Bal R

2014-06-01

Botulinum neurotoxins (BoNTs) are proteins of great interest not only because of their extreme toxicity but also paradoxically for their therapeutic applications. All the known serotypes (A-G) have varying degrees of longevity and potency inside the neuronal cell. Differential chemical modifications such as phosphorylation and ubiquitination have been suggested as possible mechanisms for their longevity, but the molecular basis of the longevity remains unclear. Since the endopeptidase domain (light chain; LC) of toxin apparently survives inside the neuronal cells for months, it is important to examine the structural features of this domain to understand its resistance to intracellular degradation. Published crystal structures (both botulinum neurotoxins and endopeptidase domain) have not provided adequate explanation for the intracellular longevity of the domain. Structural features obtained from spectroscopic analysis of LCA and LCB were similar, and a PRIME (PReImminent Molten Globule Enzyme) conformation appears to be responsible for their optimal enzymatic activity at 37°C. LCE, on the other hand, was although optimally active at 37°C, but its active conformation differed from the PRIME conformation of LCA and LCB. This study establishes and confirms our earlier finding that an optimally active conformation of these proteins in the form of PRIME exists for the most poisonous poison, botulinum neurotoxin. There are substantial variations in the structural and functional characteristics of these active molten globule related structures among the three BoNT endopeptidases examined. These differential conformations of LCs are important in understanding the fundamental structural features of proteins, and their possible connection to intracellular longevity could provide significant clues for devising new countermeasures and effective therapeutics. Copyright © 2014 Elsevier B.V. All rights reserved.

Enzymes produced by halotolerant spore-forming gram-positive bacterial strains isolated from a resting habitat (Restinga de Jurubatiba) in Rio de Janeiro, Brazil: focus on proteases.

Science.gov (United States)

D Santos, Anderson Fragoso; Pacheco, Clarissa Almeida; Valle, Roberta D Santos; Seldin, Lucy; D Santos, André Luis Souza

2014-12-01

The screening for hydrolases-producing, halotolerant, and spore-forming gram-positive bacteria from the root, rhizosphere, and non-rhizosphere soil of Blutaparon portulacoides, a plant found in the Restinga de Jurubatiba located at the northern region of Rio de Janeiro State, Brazil, resulted in the isolation of 22 strains. These strains were identified as Halobacillus blutaparonensis (n = 2), Oceanobacillus picturae (n = 5), and Oceanobacillus iheyensis (n = 15), and all showed the ability to produce different extracellular enzymes. A total of 20 isolates (90.9 %) showed activity for protease, 5 (22.7 %) for phytase, 3 (13.6 %) for cellulase, and 2 (9.1 %) for amylase. Some bacterial strains were capable of producing three (13.6 %) or two (9.1 %) distinct hydrolytic enzymes. However, no bacterial strain with ability to produce esterase and DNase was observed. The isolate designated M9, belonging to the species H. blutaparonensis, was the best producer of protease and also yielded amylase and phytase. This strain was chosen for further studies regarding its protease activity. The M9 strain produced similar amounts of protease when grown either without or with different NaCl concentrations (from 0.5 to 10 %). A simple inspection of the cell-free culture supernatant by gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of three major alkaline proteases of 40, 50, and 70 kDa, which were fully inhibited by phenylmethylsulfonyl fluoride (PMSF) and tosyl-L-phenylalanine chloromethyl ketone (TPCK) (two classical serine protease inhibitors). The secreted proteases were detected in a wide range of temperature (from 4 to 45 °C) and their hydrolytic activities were stimulated by NaCl (up to 10 %). The serine proteases produced by the M9 strain cleaved gelatin, casein, albumin, and hemoglobin, however, in different extensions. Collectively, these results suggest the potential use of the M9 strain in biotechnological

Isolation and screening of strains producing high amounts of rutin degrading enzymes from Fagopyrum tataricum seeds.

Science.gov (United States)

Zheng, Ya-Di; Luo, Qing-Lin; Zhou, Mei-Liang; Wang, De-Zhou; Zhang, Ye-Dong; Shao, Ji-Rong; Zhu, Xue-Mei; Tang, Yu

2013-02-01

The rutin degrading enzyme (RDE) was isolated and purified from tartary buckwheat seeds. The RDE was purified about 11.34-fold and its final yield was 3.5%, which was very low, due to our purification strategy of giving priority to purity over yield. The RDE molecular weight was estimated to be about 60 kDa. When rutin was used as substrate, an optimal enzyme activity was seen at around pH 5.0 and 40 °C. Strains isolation strategy characterized by the use of rutin as sole carbon source in enrichment cultures was used to isolate RDE-producing strains. Then the active strains were identified by morphology characterization and 18s rDNA-ITS (Internal Transcribed Spacer) gene sequencing. Three isolates coded as B3, W2, Y2 were successfully isolated from fusty Fagopyrum tataricum flour cultures. Strain B3 possessed the highest unit activity among these three strains, and its total activity reached up to 171.0 Unit. The active isolate (B3) could be assigned to Penicillium farinosum. When the Penicillium farinosum strains were added to tartary buckwheat flour cultures at pH 5.0, 30 °C after 5 days fermentation, the quercetin production raised up to 1.78 mg/l, almost 5.1 times higher than the fermentation without the above active strains. Hence, a new approach was available to utilize microorganism-aided fermentation for effective quercetin extraction from Fagopyrum tataricum seeds. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Botulinum neurotoxins A and E undergo retrograde axonal transport in primary motor neurons.

Directory of Open Access Journals (Sweden)

Laura Restani

2012-12-01

Full Text Available The striking differences between the clinical symptoms of tetanus and botulism have been ascribed to the different fate of the parental neurotoxins once internalised in motor neurons. Tetanus toxin (TeNT is known to undergo transcytosis into inhibitory interneurons and block the release of inhibitory neurotransmitters in the spinal cord, causing a spastic paralysis. In contrast, botulinum neurotoxins (BoNTs block acetylcholine release at the neuromuscular junction, therefore inducing a flaccid paralysis. Whilst overt experimental evidence supports the sorting of TeNT to the axonal retrograde transport pathway, recent findings challenge the established view that BoNT trafficking is restricted to the neuromuscular junction by highlighting central effects caused by these neurotoxins. These results suggest a more complex scenario whereby BoNTs also engage long-range trafficking mechanisms. However, the intracellular pathways underlying this process remain unclear. We sought to fill this gap by using primary motor neurons either in mass culture or differentiated in microfluidic devices to directly monitor the endocytosis and axonal transport of full length BoNT/A and BoNT/E and their recombinant binding fragments. We show that BoNT/A and BoNT/E are internalised by spinal cord motor neurons and undergo fast axonal retrograde transport. BoNT/A and BoNT/E are internalised in non-acidic axonal carriers that partially overlap with those containing TeNT, following a process that is largely independent of stimulated synaptic vesicle endo-exocytosis. Following intramuscular injection in vivo, BoNT/A and TeNT displayed central effects with a similar time course. Central actions paralleled the peripheral spastic paralysis for TeNT, but lagged behind the onset of flaccid paralysis for BoNT/A. These results suggest that the fast axonal retrograde transport compartment is composed of multifunctional trafficking organelles orchestrating the simultaneous transfer

Draft Genome Sequence of Komagataeibacter rhaeticus Strain AF1, a High Producer of Cellulose, Isolated from Kombucha Tea.

Science.gov (United States)

Dos Santos, Renato Augusto Corrêa; Berretta, Andresa A; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues; Goldman, Gustavo H; Riaño-Pachón, Diego M

2014-07-24

Here, we present the draft genome sequence of Komagatabaeicter rhaeticus strain AF1, which was isolated from Kombucha tea and is capable of producing high levels of cellulose. Copyright © 2014 dos Santos et al.

Helicusin E, Isochromophilone X and Isochromophilone XI: New Chloroazaphilones Produced by the Fungus Bartalinia robillardoides Strain LF550

Directory of Open Access Journals (Sweden)

Johannes F. Imhoff

2013-03-01

Full Text Available Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1 and deacetylsclerotiorin (2, three new chloroazaphilones (helicusin E (3; isochromophilone X (4 and isochromophilone XI (5 and one new pentaketide (bartanolide (6 were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.

Helicusin E, isochromophilone X and isochromophilone XI: new chloroazaphilones produced by the fungus Bartalinia robillardoides strain LF550.

Science.gov (United States)

Jansen, Nils; Ohlendorf, Birgit; Erhard, Arlette; Bruhn, Torsten; Bringmann, Gerhard; Imhoff, Johannes F

2013-03-12

Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1) and deacetylsclerotiorin (2)), three new chloroazaphilones (helicusin E (3); isochromophilone X (4) and isochromophilone XI (5)) and one new pentaketide (bartanolide (6)) were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.

Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002.

Science.gov (United States)

Therien, Jesse B; Zadvornyy, Oleg A; Posewitz, Matthew C; Bryant, Donald A; Peters, John W

2014-01-01

The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. Here we demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC 7002. Optimal growth conditions for co-cultivation of C. reinhardtii with wild-type and mutant strains of Synechococcus sp. 7002 were established. In co-culture, acetate produced by a glycogen synthase knockout mutant of Synechococcus sp. PCC 7002 was able to support the growth of a lipid-accumulating mutant strain of C. reinhardtii defective in starch production. Encapsulation of Synechococcus sp. PCC 7002 using an alginate matrix was successfully employed in co-cultures to limit growth and maintain the stability. The ability of immobilized strains of the cyanobacterium Synechococcus sp. PCC 7002 to produce acetate at a level adequate to support the growth of lipid-accumulating strains of C. reinhartdii offers a potentially practical, photosynthetic alternative to providing exogenous acetate into growth media.

Structural Analysis of Botulinum Neurotoxin Type G Receptor Binding

Energy Technology Data Exchange (ETDEWEB)

Schmitt, John; Karalewitz, Andrew; Benefield, Desire A.; Mushrush, Darren J.; Pruitt, Rory N.; Spiller, Benjamin W.; Barbieri, Joseph T.; Lacy, D. Borden (Vanderbilt); (MCW)

2010-10-19

Botulinum neurotoxin (BoNT) binds peripheral neurons at the neuromuscular junction through a dual-receptor mechanism that includes interactions with ganglioside and protein receptors. The receptor identities vary depending on BoNT serotype (A-G). BoNT/B and BoNT/G bind the luminal domains of synaptotagmin I and II, homologous synaptic vesicle proteins. We observe conditions under which BoNT/B binds both Syt isoforms, but BoNT/G binds only SytI. Both serotypes bind ganglioside G{sub T1b}. The BoNT/G receptor-binding domain crystal structure provides a context for examining these binding interactions and a platform for understanding the physiological relevance of different Syt receptor isoforms in vivo.

Characterization of extracellular vitamin B12 producing Lactobacillus plantarum strains and assessment of the probiotic potentials.

Science.gov (United States)

Li, Ping; Gu, Qing; Yang, Lanlan; Yu, Yue; Wang, Yuejiao

2017-11-01

We investigated extracellular vitamin B 12 -producing Lactobacillus strains and their characteristics in tolerance to environmental stresses, gastric acid and bile salts. Two isolates, Lactobacillus plantarum LZ95 and CY2, showed high extracellular B 12 production, 98±15μg/L and 60±9μg/L respectively. Extracellular B 12 from LZ95 were identified as adenosylcobalamin and methylcobalamin using a combination of solid phase extraction and reverse-phase HPLC, while that from CY2 was adenosylcobalamin. Both strains grew under environmental stresses, and LZ95 exhibited better tolerance to low temperature and high ethanol concentration. LZ95 also showed good viability when exposed to gastric acid (pH 2.0 and 3.0) and bile salts (0.3%) as well as good adhesion to Caco-2 cells. The viability of CY2 was significantly reduced under low pH and exposure to bile salt. Together, extracellular B 12 producer LZ95 with good probiotic properties might be a candidate for in situ B 12 fortification in the food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Update on botulinum neurotoxin use in aesthetic dermatology.

Science.gov (United States)

Ibrahim, Omer; Keller, Emily C; Arndt, Kenneth A

2014-12-01

Botulinum toxins are among the most widely studied and versatile drugs in the medicinal market. Since their extraction from Clostridium botulinum, they have been harnessed and incorporated into different formulations with varied properties and actions. These products have been used to treat countless disorders such as musculoskeletal disorders, headaches, and eye disorders, among many others. In the realm of aesthetic cutaneous medicine, the evolution and creativity in the use of botulinum toxins has been swift and ever changing. Knowledge of the science and innovation behind this toxin enables the user to provide the patient with a variety of treatment options founded in evidence-based medicine. This review will highlight the properties and actions of the newer, more recent neurotoxin preparations, as well as some of the latest and novel therapeutic applications of botulinum toxins.

Current Status and Future Directions of Botulinum Neurotoxins for Targeting Pain Processing

Directory of Open Access Journals (Sweden)

Sabine Pellett

2015-11-01

Full Text Available Current evidence suggests that botulinum neurotoxins (BoNTs A1 and B1, given locally into peripheral tissues such as skin, muscles, and joints, alter nociceptive processing otherwise initiated by inflammation or nerve injury in animal models and humans. Recent data indicate that such locally delivered BoNTs exert not only local action on sensory afferent terminals but undergo transport to central afferent cell bodies (dorsal root ganglia and spinal dorsal horn terminals, where they cleave SNAREs and block transmitter release. Increasing evidence supports the possibility of a trans-synaptic movement to alter postsynaptic function in neuronal and possibly non-neuronal (glial cells. The vast majority of these studies have been conducted on BoNT/A1 and BoNT/B1, the only two pharmaceutically developed variants. However, now over 40 different subtypes of botulinum neurotoxins (BoNTs have been identified. By combining our existing and rapidly growing understanding of BoNT/A1 and /B1 in altering nociceptive processing with explorations of the specific characteristics of the various toxins from this family, we may be able to discover or design novel, effective, and long-lasting pain therapeutics. This review will focus on our current understanding of the molecular mechanisms whereby BoNTs alter pain processing, and future directions in the development of these agents as pain therapeutics.

Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum β-lactamase producing (ESBL) strains of Enterobacteriaceae

International Nuclear Information System (INIS)

Banu, Afreen; Rathod, Vandana; Ranganath, E.

2011-01-01

Highlights: → Silver nanoparticle production by using Rhizopus stolonifer. → Antibacterial activity of silver nanoparticles against extended spectrum β-lactamase producing (ESBL) strains of Enterobacteriaceae. → Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. → Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silver nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.

Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae

Energy Technology Data Exchange (ETDEWEB)

Banu, Afreen [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India); Rathod, Vandana, E-mail: drvandanarathod@rediffmail.com [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India); Ranganath, E. [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India)

2011-09-15

Highlights: {yields} Silver nanoparticle production by using Rhizopus stolonifer. {yields} Antibacterial activity of silver nanoparticles against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae. {yields} Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. {yields} Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silver nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.

Identification and statistical optimization of fermentation conditions for a newly isolated extracellular cholesterol oxidase-producing Streptomyces cavourensis strain NEAE-42

OpenAIRE

El-Naggar, Noura El-Ahmady; El-Shweihy, Nancy M.; El-Ewasy, Sara M.

2016-01-01

Background Due to broad range of clinical and industrial applications of cholesterol oxidase, isolation and screening of bacterial strains producing extracellular form of cholesterol oxidase is of great importance. Results One hundred and thirty actinomycete isolates were screened for their cholesterol oxidase activity. Among them, a potential culture, strain NEAE-42 is displayed the highest extracellular cholesterol oxidase activity. It was selected and identified as Streptomyces cavourensis...

Safety and administration of treatment with botulinum neurotoxin for sialorrhoea in ALS patients: Review of the litterature and a proposal for tailored treatment

DEFF Research Database (Denmark)

Stokholm, Morten; Bisgård, Carsten; Vilholm, Ole Jakob

2013-01-01

Botulinum neurotoxin (BoNT) is a second-line treatment of sialorrhoea in ALS (amyotrophic lateral sclerosis) patients. This article is a review of the published literature concerning safety and administration of this treatment to ALS patients. A PubMed search was performed. All original publicati......Botulinum neurotoxin (BoNT) is a second-line treatment of sialorrhoea in ALS (amyotrophic lateral sclerosis) patients. This article is a review of the published literature concerning safety and administration of this treatment to ALS patients. A PubMed search was performed. All original...

A protein chip membrane-capture assay for botulinum neurotoxin activity

International Nuclear Information System (INIS)

Marconi, Severine; Ferracci, Geraldine; Berthomieu, Maelys; Kozaki, Shunji; Miquelis, Raymond; Boucraut, Jose; Seagar, Michael

2008-01-01

Botulinum neurotoxins A and B (BoNT/A and B) are neuromuscular blocking agents which inhibit neurotransmission by cleaving the intra-cellular presynaptic SNARE proteins SNAP-25 and VAMP2, localized respectively in plasma membrane and synaptic vesicles. These neurotoxins are both dangerous pathogens and powerful therapeutic agents with numerous clinical and cosmetic applications. Consequently there is a need for in vitro assays of their biological activity to screen for potential inhibitors and to replace the widely used in vivo mouse assay. Surface plasmon resonance (SPR) was used to measure membrane vesicle capture by antibodies against SNAP-25 and VAMP2. Substrate cleavage by BoNTs modified capture providing a method to assay toxin activity. Firstly using synaptic vesicles as a substrate, a comparison of the EC 50 s for BoNT/B obtained by SPR, ELISA or flow cytometry indicated similar sensitivity although SPR assays were more rapid. Sonication of brain or neuronal cultures generated plasma membrane fragments with accessible intra-cellular epitopes adapted to measurement of BoNT/A activity. SPR responses were proportional to antigen concentration permitting detection of as little as 4 pM SNAP-25 in crude lysates. BoNT/A activity was assayed using monoclonal antibodies that specifically recognize a SNAP-25 epitope generated by the proteolytic action of the toxin. Incubation of intact primary cultured neurons with BoNT/A yielded an EC 50 of 0.5 pM. The SPR biosensor method was sensitive enough to monitor BoNT/A and B activity in cells cultured in a 96-well format providing an alternative to experimental animals for toxicological assays

Benefits of combinative application of probiotic, enterocin M-producing strain Enterococcus faecium AL41 and Eleutherococcus senticosus in rabbits.

Science.gov (United States)

Lauková, Andrea; Simonová, Monika Pogány; Chrastinová, Ľubica; Plachá, Iveta; Čobanová, Klaudia; Formelová, Zuzana; Chrenková, Mária; Ondruška, Ľubomír; Strompfová, Viola

2016-03-01

This study presents the effects of the probiotic and enterocin M-producing strain Enterococcus faecium AL41 on microbiota, phagocytic activity (PA), oxidative stress, performance and biochemical parameters when applied individually or in combination with Eleutherococcus senticosus in rabbits. The novelty of the study lies in the use of our non-rabbit-derived strain (AL41 = CCM8558) which produces new enterocin M. Ninety-six post-weaned rabbits (Hyplus breed) aged 5 weeks were divided into three experimental groups, 24 in each: E. senticosus (ES, 30 g/100 kg) in feed, E. faecium AL41 (10(9) CFU/mL marked by rifampicin to differentiate it from other enterococci) in water, and ES + AL. AL41 colonized sufficiently in rabbits to reduce coliforms, staphylococci, pseudomonads and clostridia. Slight decrease in bacteria was also found in the caecum and appendix. Phagocytic activity was significantly increased in the experimental groups compared to the control group (CG) (p < 0.001; p < 0.05). Applications did not evoke oxidative stress. Biochemical parameters in blood and caecal organic acids were slightly influenced. Average daily weight gain was slightly higher in ES and AL + ES. Combinative application of E. faecium with E. senticosus can be beneficial in rabbits. AL41 strain alone and in combination with ES produced reduction in spoilage bacteria; the highest stimulation of PA was in the AL41 + ES group.

Botulinum Neurotoxin Detection Methods for Public Health Response and Surveillance

Directory of Open Access Journals (Sweden)

Nagarajan Thirunavukkarasu

2018-06-01

Full Text Available Botulism outbreak due to consumption of food contaminated with botulinum neurotoxins (BoNTs is a public health emergency. The threat of bioterrorism through deliberate distribution in food sources and/or aerosolization of BoNTs raises global public health and security concerns due to the potential for high mortality and morbidity. Rapid and reliable detection methods are necessary to support clinical diagnosis and surveillance for identifying the source of contamination, performing epidemiological analysis of the outbreak, preventing and responding to botulism outbreaks. This review considers the applicability of various BoNT detection methods and examines their fitness-for-purpose in safeguarding the public health and security goals.

Beltless Translocation Domain of Botulinum Neurotoxin A Embodies a Minimum Ion-conductive Channel*

OpenAIRE

Fischer, Audrey; Sambashivan, Shilpa; Brunger, Axel T.; Montal, Mauricio

2011-01-01

Botulinum neurotoxin, the causative agent of the paralytic disease botulism, is an endopeptidase composed of a catalytic domain (or light chain (LC)) and a heavy chain (HC) encompassing the translocation domain (TD) and receptor-binding domain. Upon receptor-mediated endocytosis, the LC and TD are proposed to undergo conformational changes in the acidic endocytic environment resulting in the formation of an LC protein-conducting TD channel. The mechanism of channel formation and the conformat...

Characterization of a bacteriocin-like substance produced from a novel isolated strain of Bacillus subtilis SLYY-3

Science.gov (United States)

Li, Junfeng; Li, Hongfang; Zhang, Yuanyuan; Duan, Xiaohui; Liu, Jie

2014-12-01

In the present research, the strain SLYY-3 was isolated from sediments of Jiaozhou Bay, Qingdao, China. The strain SLYY-3, which produced a bacteriocin-like substance (BLS), was characterized to be a strain of Bacillus subtillis by biochemical profiling and 16S rDNA sequence analysis. It is the first time to report that Bacillus subtilis from Jiaozhou Bay sediments could produce a BLS. The BLS of B. subtillis SLYY-3 exhibited strong inhibitory activity against gram-positive bacteria (including Staphylococcus aureus and B. subtillis) and some fungi (including Penicillium glaucum, Aspergillus niger and Aspergillus flavus). The antimicrobial activity was detected from culture in the exponential growth phase and reached its maximum when culture entered into stationary growth phase. It was thermo-tolerant even when being kept at 100°C for 60 min without losing any activity and stable over a wide pH range from 1.0 to 12.0 while being inactivated by proteolytic enzyme and trypsin, indicating the proteinaceous nature of the BLS. The BLS was purified by precipitation with hydrochloric acid (HCl) and gel filteration (Sephadex G-100). SDS-PAGE analysis of the extracellular peptides of SLYY-3 revealed a bacteriocin-like protein with a molecular mass of 66 kDa. Altogether, these characteristics indicate the potential of the BLS for food industry as a protection against pathogenic and spoilage microorganisms.

Hydrogen production from microbial strains

Science.gov (United States)

Harwood, Caroline S; Rey, Federico E

2012-09-18

The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

Prevalence and Characterization of a Binary Toxin (Actin-Specific ADP-Ribosyltransferase) from Clostridium difficile

Science.gov (United States)

Gonçalves, Carina; Decré, Dominique; Barbut, Frédéric; Burghoffer, Béatrice; Petit, Jean-Claude

2004-01-01

In addition to the two large clostridial cytotoxins (TcdA and TcdB), some strains of Clostridium difficile also produce an actin-specific ADP-ribosyltransferase, called binary toxin CDT. We used a PCR method and Southern blotting for the detection of genes encoding the enzymatic (CDTa) and binding (CDTb) components of the binary toxin in 369 strains isolated from patients with suspected C. difficile-associated diarrhea or colitis. Twenty-two strains (a prevalence of 6%) harbored both genes. When binary toxin production was assessed by Western blotting, 19 of the 22 strains reacted with antisera against the iota toxin of C. perfringens (anti-Ia and anti-Ib). Additionally, binary toxin activity, detected by the ADP-ribosyltransferase assay, was present in only 17 of the 22 strains. Subsequently, all 22 binary toxin-positive strains were tested for the production of toxins TcdA and TcdB, toxinotyped, and characterized by serogrouping, PCR ribotyping, arbitrarily primed PCR, and pulsed-field gel electrophoresis. All binary toxin-positive strains also produced TcdB and/or TcdA. However, they had significant changes in the tcdA and tcdB genes and belonged to variant toxinotypes III, IV, V, VII, IX, and XIII. We could differentiate 16 profiles by using typing methods, indicating that most of the binary toxin-positive strains were unrelated. PMID:15131151

A selective medium for the enumeration and differentiation of Lactobacillus delbrueckii ssp. bulgaricus.

Science.gov (United States)

Nwamaioha, Nwadiuto O; Ibrahim, Salam A

2018-06-01

Modified reinforced clostridial medium (mRCM) was developed and evaluated for the differential enumeration of Lactobacillus delbrueckii ssp. bulgaricus. Lactobacillus bulgaricus, an important species of lactic acid bacteria with health benefits, is used in the production of yogurt and other fermented foods. Our results showed that supplementing reinforced clostridial medium with 0.025% CaCl 2 , 0.01% uracil, and 0.2% Tween 80 (mRCM) significantly enhanced the growth rate of L. bulgaricus RR and ATCC 11842 strains as measured by the optical densities of these strains after 12 h of incubation at 42°C. The bacterial populations (plate count) of the RR and ATCC 11842 strains were 0.76 and 0.77 log cfu/g higher in mRCM than in de Man, Rogosa, and Sharpe and reinforced clostridial medium media, respectively. Conversely, the population counts for other bacterial species (Bifidobacterium, Lactobacillus rhamnosus, and Lactobacillus reuteri) were significantly inhibited in the mRCM medium. The addition of aniline blue dye to mRCM (mRCM-blue) improved the selectivity of L. bulgaricus in mixed lactic bacterial cultures compared with de Man, Rogosa, and Sharpe medium and lactic agar with regard to colony appearance and morphology. The mRCM-blue performed better than the conventional medium in culturing, enumerating, and differentiating L. bulgaricus. Therefore, mRCM-blue could be used as a selective medium to enhance the growth and differentiation of L. bulgaricus in order to meet the increasing demand for this beneficial species of bacteria. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

In-Vivo Neutralization of Botulinum Neurotoxin Serotype E Using Rabbit Polyclonal Antibody Developed against BoNT/E Light Chain.

Science.gov (United States)

Rani, Sarita; Ponmariappan, S; Sharma, Arti; Kamboj, D V; Jain, A K

2017-01-01

Clostridium botulinum is an obligate anaerobic, Gram positive bacterium that secretes extremely toxic substances known as botulinum neurotoxins (BoNTs) that cause serious paralytic illness called botulism. Based upon the serological properties, these neurotoxin have been classified into seven serotypes designated from A to G. Due to extreme toxicity of BoNTs, these neurotoxins have been designated as category A biowarfare agents. There is no commercial neutralizing antibody available for the treatment of botulism. Hence there is an urgent need to develop therapeutic intervention for prevention and cure of botulism within short period. BoNT antiserum injection is still the effective treatment. In the present study, the recombinant light chain of BoNT/E was successfully purified in soluble form. The purified rBoNT/E LC was used for the generation of polyclonal antibody in rabbit. In order to find out the neutralizing capacity of generated antisera, rabbit antiserum was incubated with 20 LD50 of botulinum neurotoxin type E for 1 hour at 37°C and then injected intraperitoneally (IP) into mice. Further in another set of experiments antiserum was administered in different ways that included administration of - antiserum and BoNT/E toxin simultaneously without preincubation, one after another at the same and different time points for its therapeutic ability. To find out cross neutralization capacity, rBoNT/E LC antiserum was pre-incubated with 5 LD50 of BoNT/A, BoNT/B, BoNT/F and then injected (IP) into mice. In all the cases mice were observed continuously for 96 hours. The results clearly indicate that developed polyclonal rabbit antiserum showed serotype specific neutralization of BoNT/E toxin only but not of BoNT/A, BoNT/B and BoNT/F. The developed antibodies will be used for preventive and therapeutic intervention of type 'E' botulism. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Amino acid neurotoxins in feathers of the Lesser Flamingo, Phoeniconaias minor.

Science.gov (United States)

Metcalf, J S; Banack, S A; Kotut, K; Krienitz, L; Codd, G A

2013-01-01

The Lesser Flamingo (Phoeniconaias minor) is known to use cyanobacteria (primarily Arthrospira) as a major food source in the East African Rift Valley lakes. Periodically, mass mortalities have occurred, associated with the cyanobacterial toxins (cyanotoxins), microcystins and anatoxin-a. Deposition of these cyanotoxins into P. minor feathers has been shown to occur, consistent with the presence of cyanotoxins in the livers, stomach and faecal contents after dietary intake. As cyanobacteria have been shown to also produce the neurotoxins β-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB), stored wing feathers, previously recovered from flamingos which had been exposed to microcystins and anatoxin-a and had subsequently died, were analysed for these neurotoxic amino acids. Trace amounts of BMAA were detected in extracts from Lake Nakuru flamingo feathers, with DAB also present at concentrations between 3.5 and 8.5 μg g(-1) dry weight in feathers from both lakes. Toxin recovery by solid-phase extraction of feather digests was tested with spiked deuterated BMAA and showed good recovery when analysed by LC-MS/MS (80-94%). This is the first report of these neurotoxic amino acids in birds. We discuss the origin and significance of DAB, alongside other cyanotoxins of dietary origin, in the feathers of the Lesser Flamingo. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fermentation and genomic analysis of acetone-uncoupled butanol production by Clostridium tetanomorphum.

Science.gov (United States)

Gong, Fuyu; Bao, Guanhui; Zhao, Chunhua; Zhang, Yanping; Li, Yin; Dong, Hongjun

2016-02-01

In typical acetone-butanol-ethanol (ABE) fermentation, acetone is the main by-product (50 % of butanol mass) of butanol production, resulting in a low yield of butanol. It is known that some Clostridium tetanomorphum strains are able to produce butanol without acetone in nature. Here, we described that C. tetanomorphum strain DSM665 can produce 4.16 g/L butanol and 4.98 g/L ethanol at pH 6.0, and 9.81 g/L butanol and 1.01 g/L ethanol when adding 1 mM methyl viologen. Butyrate and acetate could be reassimilated and no acetone was produced. Further analysis indicated that the activity of the acetate/butyrate:acetoacetyl-CoA transferase responsible for acetone production is lost in C. tetanomorphum DSM665. The genome of C. tetanomorphum DSM665 was sequenced and deposited in DDBJ, EMBL, and GenBank under the accession no. APJS00000000. Sequence analysis indicated that there are no typical genes (ctfA/B and adc) that are typically parts of an acetone synthesis pathway in C. tetanomorphum DSM665. This work provides new insights in the mechanism of clostridial butanol production and should prove useful for the design of a high-butanol-producing strain.

Pathogenicity of fumonisin-producing and nonproducing strains of Aspergillus species in section Nigri to maize ears and seedlings

Science.gov (United States)

Species of Aspergillus section Nigri are commonly associated with maize kernels, and some strains can produce fumonisin mycotoxins. However, there is little information about the extent to which these fungi contribute to fumonisin contamination in grain, the damage they cause to maize ears, or their...

Isolation and partial characterization of pigment-like antibiotics produced by a new strain of Streptosporangium isolated from an Algerian soil.

Science.gov (United States)

Boudjella, H; Bouti, K; Zitouni, A; Mathieu, F; Lebrihi, A; Sabaou, N

2007-07-01

Identification of a new actinomycete strain Sg3, belonging to the genus Streptosporangium and partial characterization of the produced antibacterial activities. The strain Sg3 was isolated from an Algerian Saharan soil and identified by morphological, chemotaxonomic and phylogenetic analyses to the genus Streptosporangium. The comparison of its physiological characteristics with those of known species of Streptosporangium showed significant differences with the nearest species Streptosporangium carneum. Analysis of the 16S rDNA sequence of strain Sg3 showed a similarity level ranging between 97% and 98.8% within Streptosporangium species, with S. carneum the most closely related. Strain Sg3 showed a red coloured antibacterial activity against gram-positive bacteria on several culture media. The purification of the red pigment by chromatographic methods led to the isolation of three active products. The (1)H nuclear magnetic resonance (NMR), mass, infrared (IR) and ultraviolet-visible (UV-VIS) data of these molecules strongly suggested that they belonged to the quinone-anthracycline group with three or more rings. Strain Sg3 represents a distinct phyletic line suggesting a new genomic species. It produces antibacterial activities identified as quinone-anthracycline aromatics. The quinone-anthracycline antibiotics are known for their antimicrobial and antineoplastic activities and are used in chemotherapy for the treatment of many cancer diseases. The present work constitutes the first stage of a whole series of studies to be realized on these antibiotics before arriving at a possible application.

Biodegradation of diesel oil by a novel microbial consortium: comparison between co-inoculation with biosurfactant-producing strain and exogenously added biosurfactants.

Science.gov (United States)

Mnif, Inès; Mnif, Sami; Sahnoun, Rihab; Maktouf, Sameh; Ayedi, Younes; Ellouze-Chaabouni, Semia; Ghribi, Dhouha

2015-10-01

Bioremediation, involving the use of microorganisms to detoxify or remove pollutants, is the most interesting strategy for hydrocarbon remediation. In this aim, four hydrocarbon-degrading bacteria were isolated from oil-contaminated soil in Tunisia. They were identified by the 16S rDNA sequence analysis, as Lysinibacillus bronitolerans RI18 (KF964487), Bacillus thuringiensis RI16 (KM111604), Bacillus weihenstephanensis RI12 (KM094930), and Acinetobacter radioresistens RI7 (KJ829530). Moreover, a lipopeptide biosurfactant produced by Bacillus subtilis SPB1, confirmed to increase diesel solubility, was tested to increase diesel biodegradation along with co-inoculation with two biosurfactant-producing strains. Culture studies revealed the enhancement of diesel biodegradation by the selected consortium with the addition of SPB1 lipopeptide and in the cases of co-inoculation by biosurfactant-producing strain. In fact, an improvement of about 38.42 and 49.65 % of diesel degradation was registered in the presence of 0.1 % lipopeptide biosurfactant and when culturing B. subtilis SPB1 strain with the isolated consortium, respectively. Furthermore, the best improvement, evaluated to about 55.4 %, was recorded when using the consortium cultured with B. subtilis SPB1 and A. radioresistens RI7 strains. Gas chromatography analyses were correlated with the gravimetric evaluation of the residual hydrocarbons. Results suggested the potential applicability of the selected consortium along with the ex situ- and in situ-added biosurfactant for the effective bioremediation of diesel-contaminated water and soil.

Draft genome sequence of Paenibacillus algorifonticola sp. nov., an antimicrobial-producing strain

Directory of Open Access Journals (Sweden)

Liying Zhu

2015-09-01

Full Text Available Paenibacillus algorifonticola sp. nov. is isolated from a cold spring sample from Xinjiang Uyghur Autonomous Region (China, a novel strain that can produce antimicrobial substance against human pathogenic bacteria and fungi, including Staphylococcus aureus and Candida albicans. Here we report a 7.60-Mb assembly of its genome sequence and other useful information, including the coding sequences (CDSs responsible for the biosynthesis of antibacterial factors, anaerobic respiration and several immune-associated reactions. Also, prospective studies on P. algorifonticola sp. nov. in the cold spring might offer a potential source for the discovery of bioactive compounds with medical value. The data repository is deposited on the website http://www.ncbi.nlm.nih.gov/nuccore/LAQO00000000 and the accession number is LAQO00000000.

Characterization of hydrocarbon-degrading and biosurfactant-producing Pseudomonas sp. P-1 strain as a potential tool for bioremediation of petroleum-contaminated soil.

Science.gov (United States)

Pacwa-Płociniczak, Magdalena; Płaza, Grażyna Anna; Poliwoda, Anna; Piotrowska-Seget, Zofia

2014-01-01

The Pseudomonas sp. P-1 strain, isolated from heavily petroleum hydrocarbon-contaminated soil, was investigated for its capability to degrade hydrocarbons and produce a biosurfactant. The strain degraded crude oil, fractions A5 and P3 of crude oil, and hexadecane (27, 39, 27 and 13% of hydrocarbons added to culture medium were degraded, respectively) but had no ability to degrade phenanthrene. Additionally, the presence of gene-encoding enzymes responsible for the degradation of alkanes and naphthalene in the genome of the P-1 strain was reported. Positive results of blood agar and methylene blue agar tests, as well as the presence of gene rhl, involved in the biosynthesis of rhamnolipid, confirmed the ability of P-1 for synthesis of glycolipid biosurfactant. 1H and 13C nuclear magnetic resonance, Fourier transform infrared spectrum and mass spectrum analyses indicated that the extracted biosurfactant was affiliated with rhamnolipid. The results of this study indicate that the P-1 and/or biosurfactant produced by this strain have the potential to be used in bioremediation of hydrocarbon-contaminated soils.

Geochemical legacies and the future health of cities: A tale of two neurotoxins in urban soils

Directory of Open Access Journals (Sweden)

Gabriel M. Filippelli

2015-07-01

Full Text Available Abstract The past and future of cities are inextricably linked, a linkage that can be seen clearly in the long-term impacts of urban geochemical legacies. As loci of population as well as the means of employment and industry to support these populations, cities have a long history of co-locating contaminating practices and people, sometimes with negative implications for human health. Working at the intersection between environmental processes, communities, and human health is critical to grapple with environmental legacies and to support healthy, sustainable, and growing urban populations. An emerging area of environmental health research is to understand the impacts of chronic exposures and exposure mixtures—these impacts are poorly studied, yet may pose a significant threat to population health. Acute exposure to lead (Pb, a powerful neurotoxin to which children are particularly susceptible, has largely been eliminated in the U.S. and other countries through policy-based restrictions on leaded gasoline and lead-based paints. But the legacy of these sources remains in the form of surface soil Pb contamination, a common problem in cities and one that has only recently emerged as a widespread chronic exposure mechanism in cities. Some urban soils are also contaminated with another neurotoxin, mercury (Hg. The greatest human exposure to Hg is through fish consumption, so eating fish caught in urban areas presents risks for toxic Hg exposure. The potential double impact of chronic exposure to these two neurotoxins is pronounced in cities. Overall, there is a paradigmatic shift from reaction to and remediation of acute exposures towards a more nuanced understanding of the dynamic cycling of persistent environmental contaminants with resultant widespread and chronic exposure of inner-city dwellers, leading to chronic toxic illness and disability at substantial human and social cost.

Label-Free (XIC) Quantification of Venom Procoagulant and Neurotoxin Expression in Related Australian Elapid Snakes Gives Insight into Venom Toxicity Evolution.

Science.gov (United States)

Skejic, Jure; Steer, David L; Dunstan, Nathan; Hodgson, Wayne C

2015-11-06

This study demonstrates a direct role of venom protein expression alteration in the evolution of snake venom toxicity. Avian skeletal muscle contractile response to exogenously administered acetylcholine is completely inhibited upon exposure to South Australian and largely preserved following exposure to Queensland eastern brown snake Pseudonaja textilis venom, indicating potent postsynaptic neurotoxicity of the former and lack thereof of the latter venom. Label-free quantitative proteomics reveals extremely large differences in the expression of postsynaptic three-finger α-neurotoxins in these venoms, explaining the difference in the muscle contractile response and suggesting that the type of toxicity induced by venom can be modified by altered expression of venom proteins. Furthermore, the onset of neuromuscular paralysis in the rat phrenic nerve-diaphragm preparation occurs sooner upon exposure to the venom (10 μg/mL) with high expression of α-neurotoxins than the venoms containing predominately presynaptic β-neurotoxins. The study also finds that the onset of rat plasma coagulation is faster following exposure to the venoms with higher expression of venom prothrombin activator subunits. This is the first quantitative proteomic study that uses extracted ion chromatogram peak areas (MS1 XIC) of distinct homologous tryptic peptides to directly show the differences in the expression of venom proteins.

Evolution of a recombinant (gucoamylase-producing) strain of Fusarium venenatum A3/5 in chemostat culture.

Science.gov (United States)

Wiebe, M G; Robson, G D; Shuster, J; Trinci, A P

2001-04-20

Fusarium venenatum JeRS 325 is a transformant of strain A3/5 which produces Aspergillus niger glucoamylase (GAM) under the control of a Fusarium oxysporum trypsin-like protease promoter. The evolution of JeRS 325 was studied in glucose-limited chemostat cultures grown on NaNO3 or (NH4)2SO4 as the nitrogen source. Thirteen mutants which were more highly branched and four mutants which were more sparsely branched than the parental strain were isolated from the NaNO3 chemostat. The highly branched mutants detected in this chemostat did not displace the sparsely branched population. The mutants isolated from the NaNO3 chemostat complemented representative strains previously isolated from glucose-limited chemostat cultures of F. venenatum A3/5 grown on (NH4)2SO4, but showed little complementation between themselves. By contrast, a highly branched mutant isolated from the (NH4)2SO4 chemostat culture displaced the sparsely branched mycelial population. None of the mutants isolated from the NaNO3 or (NH4)2SO4 chemostats produced as much GAM as JeRS 325. Southern blot analysis showed that all except one mutant had lost copies of both the glucoamylase and the acetamidase (the selectable marker) genes. However, specific GAM production was not necessarily correlated with the extent of glaA gene loss observed. Further, 10 of the mutants had lost the ability to grow on acetamide as the sole nitrogen source, although they retained copies of the amdS gene. In competition studies, mutants which could not utilize acetamide displaced mutants which could. The presence of foreign DNA in JeRS 325 resulted in a reduced specific growth rate (compared to A3/5), but the presence of the foreign DNA did not prevent the evolution of the strain or the isolation of mutants which had improved growth rates. Copyright 2001 John Wiley & Sons, Inc.

Economic analysis and budget impact of clostridial collagenase ointment compared with medicinal honey for treatment of pressure ulcers in the US

Directory of Open Access Journals (Sweden)

Mearns ES

2017-08-01

Full Text Available Elizabeth S Mearns,1 Michael Liang,1 Brendan L Limone,1 Adrienne M Gilligan,1 Jeffrey D Miller,1 Kathleen D Schaum,2 Curtis R Waycaster2 1Truven Health Analytics, an IBM Company, Cambridge, MA, USA; 2Smith & Nephew, Inc., Fort Worth, TX, USA Objectives: Pressure ulcer (PU treatment poses significant clinical and economic challenges to health-care systems. The aim of this study was to assess the cost-effectiveness and budget impact of enzymatic debridement with clostridial collagenase ointment (CCO compared with autolytic debridement with medicinal honey (MH for PU treatment from a US payer/Medicare perspective in the hospital outpatient department setting.Methods: A cost-effectiveness analysis using a Markov model was developed using a 1-week cycle length across a 1-year time horizon. The three health states were inflammation/senescence, granulation/proliferation (ie, patients achieving 100% granulation, and epithelialization. Data sources included the US Wound Registry, Medicare fee schedules, and other published clinical and cost studies about PU treatment.Results: In the base case analysis over a 1-year time horizon, CCO was the economically dominant strategy (ie, simultaneously conferring greater benefit at less cost. Patients treated with CCO experienced 22.7 quality-adjusted life weeks (QALWs at a cost of $6,161 over 1 year, whereas MH patients experienced 21.9 QALWs at a cost of $7,149. Patients treated with CCO achieved 11.5 granulation weeks and 6.0 epithelization weeks compared with 10.6 and 4.4 weeks for MH, respectively. The number of clinic visits was 40.1 for CCO vs 43.4 for MH, and the number of debridements was 12.3 for CCO compared with 17.6 for MH. Probabilistic sensitivity analyses determined CCO dominant in 72% of 10,000 iterations and cost-effective in 91%, assuming a benchmark willingness-to-pay threshold of $50,000/quality-adjusted life year ($962/QALW. The budget impact analysis showed that for every 1% of patients

Extracellular polymeric substances (EPS) producing bacterial strains of municipal wastewater sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering.

Science.gov (United States)

Bala Subramanian, S; Yan, S; Tyagi, R D; Surampalli, R Y

2010-04-01

Wastewater treatment plants often face the problems of sludge settling mainly due to sludge bulking. Generally, synthetic organic polymer and/or inorganic coagulants (ferric chloride, alum and quick lime) are used for sludge settling. These chemicals are very expensive and further pollute the environment. Whereas, the bioflocculants are environment friendly and may be used to flocculate the sludge. Extracellular polymeric substances (EPS) produced by sludge microorganisms play a definite role in sludge flocculation. In this study, 25 EPS producing strains were isolated from municipal wastewater treatment plant. Microorganisms were selected based on EPS production properties on solid agar medium. Three types of EPS (slime, capsular and bacterial broth mixture of both slime and capsular) were harvested and their characteristics were studied. EPS concentration (dry weight), viscosity and their charge (using a Zetaphoremeter) were also measured. Bioflocculability of obtained EPS was evaluated by measuring the kaolin clay flocculation activity. Six bacterial strains (BS2, BS8, BS9, BS11, BS15 and BS25) were selected based on the kaolin clay flocculation. The slime EPS was better for bioflocculation than capsular EPS and bacterial broth. Therefore, extracted slime EPS (partially purified) from six bacterial strains was studied in terms of sludge settling [sludge volume index (SVI)] and dewatering [capillary suction time (CST)]. Biopolymers produced by individual strains substantially improved dewaterability. The extracted slime EPS from six different strains were partially characterized. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Beltless translocation domain of botulinum neurotoxin A embodies a minimum ion-conductive channel.

Science.gov (United States)

Fischer, Audrey; Sambashivan, Shilpa; Brunger, Axel T; Montal, Mauricio

2012-01-13

Botulinum neurotoxin, the causative agent of the paralytic disease botulism, is an endopeptidase composed of a catalytic domain (or light chain (LC)) and a heavy chain (HC) encompassing the translocation domain (TD) and receptor-binding domain. Upon receptor-mediated endocytosis, the LC and TD are proposed to undergo conformational changes in the acidic endocytic environment resulting in the formation of an LC protein-conducting TD channel. The mechanism of channel formation and the conformational changes in the toxin upon acidification are important but less well understood aspects of botulinum neurotoxin intoxication. Here, we have identified a minimum channel-forming truncation of the TD, the "beltless" TD, that forms transmembrane channels with ion conduction properties similar to those of the full-length TD. At variance with the holotoxin and the HC, channel formation for both the TD and the beltless TD occurs independent of a transmembrane pH gradient. Furthermore, acidification in solution induces moderate secondary structure changes. The subtle nature of the conformational changes evoked by acidification on the TD suggests that, in the context of the holotoxin, larger structural rearrangements and LC unfolding occur preceding or concurrent to channel formation. This notion is consistent with the hypothesis that although each domain of the holotoxin functions individually, each domain serves as a chaperone for the others.

The effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on model bacterial strains and isolates from industrial wastewater.

Science.gov (United States)

Vasileva-Tonkova, Evgenia; Sotirova, Anna; Galabova, Danka

2011-02-01

In this study, the effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on bacterial strains, laboratory strains, and isolates from industrial wastewater was investigated. It was shown that biosurfactant, depending on the concentration, has a neutral or detrimental effect on the growth and protein release of model Gram (+) strain Bacillus subtilis 168. The growth and protein release of model Gram (-) strain Pseudomonas aeruginosa 1390 was not influenced by the presence of biosurfactant in the medium. Rhamnolipid biosurfactant at the used concentrations supported the growth of some slow growing on hexadecane bacterial isolates, members of the microbial community. Changes in cell surface hydrophobicity and permeability of some Gram (+) and Gram (-) isolates in the presence of rhamnolipid biosurfactant were followed in experiments in vitro. It was found that bacterial cells treated with biosurfactant became more or less hydrophobic than untreated cells depending on individual characteristics and abilities of the strains. For all treated strains, an increase in the amount of released protein was observed with increasing the amount of biosurfactant, probably due to increased cell permeability as a result of changes in the organization of cell surface structures. The results obtained could contribute to clarify the relationships between members of the microbial community as well as suggest the efficiency of surface properties of rhamnolipid biosurfactant from Pseudomonas fluorescens making it potentially applicable in bioremediation of hydrocarbon-polluted environments.

Analysis of potential fumonisin-producing Fusarium species in corn products from three main maize-producing areas in eastern China.

Science.gov (United States)

Zhang, Liping; Wang, Jiansheng; Zhang, Chulong; Wang, Qiaomei

2013-02-01

Fusarium species are common fungal contaminants of maize and a number of them can produce mycotoxin fumonisins. China is one of the largest maize producers in the world. This study investigated the contamination of maize samples from three areas in eastern China by Fusarium and fumonisin-producing fungi as well as their fumonisin-producing potential. A total of 22 Fusarium strains were isolated, 19 of which were able to produce fumonisin. Among the 19 strains, 16 belonged to F. verticillioides, two to F. subglutinans and one to F. proliferatum. The majority (17/19) of the fumonisin-forming strains were high FB(1) producers, which is a potential health risk for the population in these areas. Fusarium contamination in samples from the mideastern area was the most serious (11 Fusarium strains, with nine producing fumonisin, isolated from 24 samples), followed by the northeastern area (nine Fusarium strains, with all nine producing fumonisin, isolated from 21 samples) and the southeastern area (two Fusarium strains, with one producing fumonisin, isolated from 19 samples). Although the overall levels of FBs and contamination by fumonisin-producing fungi in corn samples were not serious, the contaminating Fusarium strains possessed fairly strong toxicogenic ability and potential risk for food safety. Copyright © 2012 Society of Chemical Industry.

Modulation of neurotransmitter release in the region of the caudate nucleus by diet and neurotoxins

Energy Technology Data Exchange (ETDEWEB)

Kurstjens, N P

1987-01-01

In this thesis the effects of dietary manipulation, ethanol and neurotoxins on the basal and electrically evoked release of dopamine and acetylcholine from the caudate nucleus of mature animals are presented together with an evaluation of the presynaptic acetylcholine and dopamine receptors controlling acetylcholine and dopamine release. A standardised superfusion technique was used to monitor the effect of apomorphine, in the presence of (R-S)- sulpiride or haloperidol, on the electrically induced release of (/sup 3/ H)-acetylcholine in slices of rat corpus striatum. The effect of ethanol and dietary manipulation on the basal and electrically evoke release of (/sup 3/H)-acetylfholine from rat striatal slices, in the presence of specific agonists and antagonists was evaluated. From this study it is possible to deduce that diet and neurotoxins exerted a measurable effect on the mechanisms controlling release of neurotransmitters in the region of the caudate nucleus. These changes were determined in mature animals previously considered to have cerebral activity, which was not subject to dietary fluctuaations. No changes in the activity of the presynaptic dopamine receptor of the acetylcholine nerve terminals of the striatal slice could be measured.

Structural characterization of bioengineered α-D-glucans produced by mutant glucansucrase GTF180 enzymes of lactobacillus reuteri strain 180

NARCIS (Netherlands)

Leeuwen, S.S. van; Kralj, S.; Eeuwema, W.; Gerwig, G.J.; Dijkhuizen, L.; Kamerling, J.P.

2009-01-01

Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

Structural Characterization of Bioengineered alpha-D-Glucans Produced by Mutant Glucansucrase GTF180 Enzymes of Lactobacillus reuteri Strain 180

NARCIS (Netherlands)

van Leeuwen, Sander S.; Kralj, Slavko; Eeuwema, Wieger; Gerwig, Gerrit J.; Dijkhuizen, Lubbert; Kamerling, Johannis P.

Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

Genetic segregation in a high-yielding streptomycin-producing strain of Streptomyces griseus.

Science.gov (United States)

Roth, M; Schwalenberg, B; Reiche, R; Noack, D; Geuther, R; Eritt, I

1982-01-01

The streptomycin-producing Streptomyces griseus HP spontaneously segregated non-reverting derivatives with altered phenotypes. Clones characterized by increased spore formation and decreased streptomycin production were found. Two other types of derivatives were defective in aerial mycelium and streptomycin formation as well, but differed in the capacity to synthesize a yellow pigment. These derivatives were examined with respect to further properties. The stability of S. griseus HP was investigated in relation to conditions of continuous culture. Both at 26 and 30 degrees C, under glycerol and NH4Cl limitation a rapid segregation and enrichment of streptomycin-non-producing derivatives occurred. At 34 degrees C and glycerol limitation segregation began only after about 35 generations of continuous culture. In NH4Cl-limited chemostats the original strain was stable during 80 generations. In the course of the continuous culture experiments it was shown that the onset of genetic segregation within mycelia can be detected before it becomes obvious in colonies grown from the mycelia. This was achieved by fractionation of the mycelia by protoplast formation and subsequent plating on regeneration medium allowing colony growth and differentiation.

Ophiophagus hannah Venom: Proteome, Components Bound by Naja kaouthia Antivenin and Neutralization by N. kaouthia Neurotoxin-Specific Human ScFv

Directory of Open Access Journals (Sweden)

Witchuda Danpaiboon

2014-05-01

Full Text Available Venomous snakebites are an important health problem in tropical and subtropical countries. King cobra (Ophiophagus hannah is the largest venomous snake found in South and Southeast Asia. In this study, the O. hannah venom proteome and the venom components cross-reactive to N. kaouthia monospecific antivenin were studied. O. hannah venom consisted of 14 different protein families, including three finger toxins, phospholipases, cysteine-rich secretory proteins, cobra venom factor, muscarinic toxin, L-amino acid oxidase, hypothetical proteins, low cysteine protein, phosphodiesterase, proteases, vespryn toxin, Kunitz, growth factor activators and others (coagulation factor, endonuclease, 5’-nucleotidase. N. kaouthia antivenin recognized several functionally different O. hannah venom proteins and mediated paratherapeutic efficacy by rescuing the O. hannah envenomed mice from lethality. An engineered human ScFv specific to N. kaouthia long neurotoxin (NkLN-HuScFv cross-neutralized the O. hannah venom and extricated the O. hannah envenomed mice from death in a dose escalation manner. Homology modeling and molecular docking revealed that NkLN-HuScFv interacted with residues in loops 2 and 3 of the neurotoxins of both snake species, which are important for neuronal acetylcholine receptor binding. The data of this study are useful for snakebite treatment when and where the polyspecific antivenin is not available. Because the supply of horse-derived antivenin is limited and the preparation may cause some adverse effects in recipients, a cocktail of recombinant human ScFvs for various toxic venom components shared by different venomous snakes, exemplified by the in vitro produced NkLN-HuScFv in this study, should contribute to a possible future route for an improved alternative to the antivenins.

Ophiophagus hannah venom: proteome, components bound by Naja kaouthia antivenin and neutralization by N. kaouthia neurotoxin-specific human ScFv.

Science.gov (United States)

Danpaiboon, Witchuda; Reamtong, Onrapak; Sookrung, Nitat; Seesuay, Watee; Sakolvaree, Yuwaporn; Thanongsaksrikul, Jeeraphong; Dong-din-on, Fonthip; Srimanote, Potjanee; Thueng-in, Kanyarat; Chaicumpa, Wanpen

2014-05-13

Venomous snakebites are an important health problem in tropical and subtropical countries. King cobra (Ophiophagus hannah) is the largest venomous snake found in South and Southeast Asia. In this study, the O. hannah venom proteome and the venom components cross-reactive to N. kaouthia monospecific antivenin were studied. O. hannah venom consisted of 14 different protein families, including three finger toxins, phospholipases, cysteine-rich secretory proteins, cobra venom factor, muscarinic toxin, L-amino acid oxidase, hypothetical proteins, low cysteine protein, phosphodiesterase, proteases, vespryn toxin, Kunitz, growth factor activators and others (coagulation factor, endonuclease, 5'-nucleotidase). N. kaouthia antivenin recognized several functionally different O. hannah venom proteins and mediated paratherapeutic efficacy by rescuing the O. hannah envenomed mice from lethality. An engineered human ScFv specific to N. kaouthia long neurotoxin (NkLN-HuScFv) cross-neutralized the O. hannah venom and extricated the O. hannah envenomed mice from death in a dose escalation manner. Homology modeling and molecular docking revealed that NkLN-HuScFv interacted with residues in loops 2 and 3 of the neurotoxins of both snake species, which are important for neuronal acetylcholine receptor binding. The data of this study are useful for snakebite treatment when and where the polyspecific antivenin is not available. Because the supply of horse-derived antivenin is limited and the preparation may cause some adverse effects in recipients, a cocktail of recombinant human ScFvs for various toxic venom components shared by different venomous snakes, exemplified by the in vitro produced NkLN-HuScFv in this study, should contribute to a possible future route for an improved alternative to the antivenins.

Effect of γ-Aminobutyric Acid-producing Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress

Directory of Open Access Journals (Sweden)

Y. Z. Zhu

2015-07-01

Full Text Available Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164 at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i 0 mg/kg, ii 25 mg/kg, iii 50 mg/kg, and iv 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05 by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05 than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009 and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to

Microstructure and Textural Properties of Yoghurts Produced by Exopolysaccharides- Producing Starter Cultures

DEFF Research Database (Denmark)

Zhang, Lanjun

conferred a ropy texture and resulted in yoghurts with decreased water holding capacity and an open microstructure. In addition, one of the LB strains with high amounts of EPS producing capacity improved water retention, when it was combined with an ST strain that produced negligible amounts of EPS...

Structural Basis of the pH-Dependent Assembly of a Botulinum Neurotoxin Complex

OpenAIRE

Matsui, Tsutomu; Gu, Shenyan; Lam, Kwok-ho; Carter, Lester G.; Rummel, Andreas; Mathews, Irimpan I.; Jin, Rongsheng

2014-01-01

Botulinum neurotoxins (BoNTs) are among the most poisonous biological substances known. They assemble with non-toxic non-hemagglutinin (NTNHA) protein to form the minimally functional progenitor toxin complexes (M-PTC), which protects BoNT in the gastrointestinal tract and release it upon entry into the circulation. Here we provide molecular insight into the assembly between BoNT/A and NTNHA-A using small-angle X-ray scattering. We found that the free form BoNT/A maintains a pH-independent co...

Detection and confirmation of Clostridium botulinum in water used for cooling at a plant producing low-acid canned foods.

Science.gov (United States)

Sachdeva, Amita; Defibaugh-Chávez, Stephanie L H; Day, James B; Zink, Donald; Sharma, Shashi K

2010-11-01

Our laboratory tested water samples used for cooling low-acid canned foods at a canning facility under investigation by the U.S. Food and Drug Administration. We used an enzyme-linked immunosorbent assay with digoxigenin-labeled antibodies (DIG-ELISA) and real-time PCR as screening methods and confirmed the presence of neurotoxin-producing Clostridium botulinum in the samples by mouse bioassay.

Detection and Confirmation of Clostridium botulinum in Water Used for Cooling at a Plant Producing Low-Acid Canned Foods▿

OpenAIRE

Sachdeva, Amita; Defibaugh-Chávez, Stephanie L. H.; Day, James B.; Zink, Donald; Sharma, Shashi K.

2010-01-01

Our laboratory tested water samples used for cooling low-acid canned foods at a canning facility under investigation by the U.S. Food and Drug Administration. We used an enzyme-linked immunosorbent assay with digoxigenin-labeled antibodies (DIG-ELISA) and real-time PCR as screening methods and confirmed the presence of neurotoxin-producing Clostridium botulinum in the samples by mouse bioassay.

Pilot cohort study of endoscopic botulinum neurotoxin injection in Parkinson's disease.

Science.gov (United States)

Triadafilopoulos, George; Gandhy, Rita; Barlow, Carrolee

2017-11-01

Gastrointestinal symptoms, such as dysphagia, postprandial bloating, and defecatory straining are common in Parkinson's Disease (PD) and they impact quality of life. Endoscopic botulinum neurotoxin (BoNT) injection has been used in the treatment of dysphagia, gastroparesis and chronic anismus. To examine the feasibility, safety and efficacy of endoscopically delivered BoNT injection to distal esophagus, pylorus or anal canal aiming at relieving regional gastrointestinal symptoms in patients with PD. This is a retrospective open cohort pilot study to assess the clinical response to endoscopic BoNT injection on selected PD patients with symptoms and identifiable abnormalities on high-resolution manometry and wireless motility capsule, to generate early uncontrolled data on feasibility, tolerability, safety and efficacy. Baseline symptoms and response to therapy were assessed by questionnaires. Fourteen PD patients (10 M:4 F), mean age 73 (range: 62-93) were treated. Three patients had esophageal Botox for ineffective esophageal motility (IEM) (n = 1), esophago-gastric junction outlet obstruction (EGJOO) & IEM (n = 1), and diffuse esophageal spasm (DES) (n = 1). Nine patients were treated with pyloric BoNT injection for gastroparesis with mean gastric transit time of 21.2 h; range 5.2-44.2 h. Two patients received anal Botox for defecatory dyssynergia ((Type I) (n = 1) and overlap (slow-transit and dyssynergic) constipation (n = 1). Endoscopic BoNT injection (100-200 units) was well tolerated and there were no significant adverse events. Endoscopic BoNT injection to esophagus, pylorus or anal canal is safe, well-tolerated and leads to symptomatic improvement that lasts up to several months. The procedure can be repeated as needed and combined with other therapies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study on breeding of daptomycin-producing strains by nitrogen ion implantation

International Nuclear Information System (INIS)

Zhou Jian; Liu Ying; Fang Dongsheng; Jiang Hong; Zhang Yin; Gao Wuyan

2008-01-01

Streptomyces roseosporus C20, the bacteria used in production of daptomycin, were implanted with (15-200)x10 13 /cm 2 of 20keV N + ions. Survival rate of the bacteria at different absorbed doses was investigated, and mutagenic effects of the microbe were studied. After breeding under the selection pressure of resistance to streptomycin (the lethal concentration is 1.2μg/mL), several mutant strains with higher yields of daptomycin have been obtained. One of mutant strains, N3-36, can increase up to 126% compared to the original strain. It also shows that the mutant strains have high genetic stability. (authors)

Activities of beta-lactam antibiotics against Escherichia coli strains producing extended-spectrum beta-lactamases.

Science.gov (United States)

Jacoby, G A; Carreras, I

1990-01-01

Seven extended-spectrum beta-lactamases related to TEM and four enzymes derived from SHV-1 were transferred to a common Escherichia coli host so that the activity of a variety of beta-lactams could be tested in a uniform genetic environment. For most derivatives, penicillinase activity was 10% or less than that of strains making TEM-1, TEM-2, or SHV-1 beta-lactamase, suggesting that reduced catalytic efficiency accompanied the broader substrate spectrum. Despite this deficit, resistance to aztreonam, carumonam, cefdinir, cefepime, cefixime, cefmenoxime, cefotaxime, cefotiam, cefpirome, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefuroxime, and E1040 was enhanced. For strains producing TEM-type enzymes, however, MICs of carumonam, cefepime, cefmenoxime, cefotiam, cefpirome, and ceftibuten were 8 micrograms/ml or less. Susceptibilities of cefmetazole, cefotetan, cefoxitin, flomoxef, imipenem, meropenem, moxalactam, temocillin, FCE 22101, and Sch 34343 were unaffected. FCE 22101, imipenem, meropenem, and Sch 34343 were inhibitory for all strains at 1 microgram/ml or less. In E. coli an OmpF- porin mutation in combination with an extended-spectrum beta-lactamase enhanced resistance to many of these agents, but generally by only fourfold. Hyperproduction of chromosomal AmpC beta-lactamase increased resistance to 7-alpha-methoxy beta-lactams but not that to temocillin. When tested at 8 micrograms/ml, clavulanate was more potent than sulbactam or tazobactam in overcoming resistance to ampicillin, while cefoperazone-sulbactam was more active than ticarcillin-clavulanate or piperacillin-tazobactam, especially against TEM-type extended-spectrum beta-lactamases. PMID:2193623

[Distiller Yeasts Producing Antibacterial Peptides].

Science.gov (United States)

Klyachko, E V; Morozkina, E V; Zaitchik, B Ts; Benevolensky, S V

2015-01-01

A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

Selection and protein sds-page identification of a new high-producing polysaccharide strain of Spirulina platensis

International Nuclear Information System (INIS)

Wang Zhiping; Liu Yanhui

2004-01-01

The relationship between anti-radiation capacity and polysaccharide contents of ten Spirulina platensis strains were studied. The results showed that the correlation coefficient between 60 Co γ-ray half-lethal dose (LD 50 ) and polysaccharide contents of the 10 strains was 0.9873. After the single cells or spheroplasts of Sp-08 were treated by 0.6%EMS and 2.4 kGy 60 Co γ-ray irradiation, four morphological mutant named Sp-08A, Sp-08B, Sp-08C and Sp-08D, which could endure about 7.0 kGy γ-ray irradiation, were obtained. The polysaccharide contents of Sp-08A, Sp-08B, Sp-08C and Sp-08D, were 32.8%, 17.3%, 3.4% and 42.3% higher than that of their parent Sp-08, respectively. The results of protein SDS-PAGE analysis showed that the heredity of Sp-08A, Sp-08C and Sp-08D were mutated. Therefore, Sp-08A was a perfect high-producing polysaccharide strain with excellent characteristics of morphology and growth. Now, Sp-08A is applied in mass cultivation and industrialization. (authors)

Enzymic hydrolysis of xylans. I. A high xylanase and beta-xylosidase producing strain of Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Conrad, D.

1981-01-01

Aspergillus niger, strain 110.42 (CBS) was selected as a producer of high xylanolytic activities. The time course of xylanase and beta-xylosidase production as well as the effect of pH and temperature on the activity of these enzymes were studied. High-performance liquid chromatography analysis of the enzymic degradation of arabinoxylan showed a nearly complete conversion to pentose sugars. Aspects of using crude xylanase preparations for enzymic saccharification of xylans are discussed.

Isolation and identification of a thermophilic strain producing trehalose synthase from geothermal water in China.

Science.gov (United States)

Zhu, Yueming; Zhang, Jun; Wei, Dongsheng; Wang, Yufan; Chen, Xiaoyun; Xing, Laijun; Li, Mingchun

2008-08-01

A slightly thermophilic strain, CBS-01, producing trehalose synthase (TreS), was isolated from geothermal water in this study. According to the phenotypic characteristics and phylogenetic analysis of the 16s rRNA gene sequence, it was identified as Meiothermus ruber. The trehalose synthase gene of Meiothermus ruber CBS-01 was cloned by polymerase chain reaction and sequenced. The TreS gene consisted of 2,895 nucleotides, which specified a 964-amino-acid protein. This novel TreS catalyzed reversible interconversion of maltose and trehalose.

Genealogy profiling through strain improvement by using metabolic network analysis: metabolic flux genealogy of several generations of lysine-producing corynebacteria.

Science.gov (United States)

Wittmann, Christoph; Heinzle, Elmar

2002-12-01

A comprehensive approach of metabolite balancing, (13)C tracer studies, gas chromatography-mass spectrometry, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and isotopomer modeling was applied for comparative metabolic network analysis of a genealogy of five successive generations of lysine-producing Corynebacterium glutamicum. The five strains examined (C. glutamicum ATCC 13032, 13287, 21253, 21526, and 21543) were previously obtained by random mutagenesis and selection. Throughout the genealogy, the lysine yield in batch cultures increased markedly from 1.2 to 24.9% relative to the glucose uptake flux. Strain optimization was accompanied by significant changes in intracellular flux distributions. The relative pentose phosphate pathway (PPP) flux successively increased, clearly corresponding to the product yield. Moreover, the anaplerotic net flux increased almost twofold as a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes to cover the increased demand for lysine formation; thus, the overall increase was a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes. The relative flux through isocitrate dehydrogenase dropped from 82.7% in the wild type to 59.9% in the lysine-producing mutants. In contrast to the NADPH demand, which increased from 109 to 172% due to the increasing lysine yield, the overall NADPH supply remained constant between 185 and 196%, resulting in a decrease in the apparent NADPH excess through strain optimization. Extrapolated to industrial lysine producers, the NADPH supply might become a limiting factor. The relative contributions of PPP and the tricarboxylic acid cycle to NADPH generation changed markedly, indicating that C. glutamicum is able to maintain a constant supply of NADPH under completely different flux conditions. Statistical analysis by a Monte Carlo approach revealed high precision for the estimated fluxes, underlining the

Comparison of oral toxicological properties of botulinum neurotoxin serotypes A and B.

Science.gov (United States)

Cheng, Luisa W; Henderson, Thomas D

2011-07-01

Botulinum neurotoxins (BoNTs) are among the most potent biological toxins for humans. Of the seven known serotypes (A-G) of BoNT, serotypes A, B and E cause most of the foodborne intoxications in humans. BoNTs in nature are associated with non-toxic accessory proteins known as neurotoxin-associated proteins (NAPs), forming large complexes that have been shown to play important roles in oral toxicity. Using mouse intraperitoneal and oral models of botulism, we determined the dose response to both BoNT/B holotoxin and complex toxins, and compared the toxicities of BoNT/B and BoNT/A complexes. Although serotype A and B complexes have similar NAP composition, BoNT/B formed larger-sized complexes, and was approximately 90 times more lethal in mouse oral intoxications than BoNT/A complexes. When normalized by mean lethal dose, mice orally treated with high doses of BoNT/B complex showed a delayed time-to-death when compared with mice treated with BoNT/A complex. Furthermore, we determined the effect of various food matrices on oral toxicity of BoNT/A and BoNT/B complexes. BoNT/B complexes showed lower oral bioavailability in liquid egg matrices when compared to BoNT/A complexes. In summary, our studies revealed several factors that can either enhance or reduce the toxicity and oral bioavailability of BoNTs. Dissecting the complexities of the different BoNT serotypes and their roles in foodborne botulism will lead to a better understanding of toxin biology and aid future food risk assessments. Published by Elsevier Ltd.

Characterization of Hemagglutinin Negative Botulinum Progenitor Toxins

Directory of Open Access Journals (Sweden)

Suzanne R. Kalb

2017-06-01

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

[Genetic diversity of extraintestinal Escherichia coli strains producers of beta-lactamases TEM, SHV and CTX-M associated with healthcare].

Science.gov (United States)

Varela, Yasmin; Millán, Beatriz; Araque, María

2017-06-01

There are few reports from Venezuela describing the genetic basis that sustains the pathogenic potential and phylogenetics of Escherichia coli extraintestinal strains isolated in health care units. To establish the genetic diversity of extraintestinal E. coli strains producers of betalactamases TEM, SHV and CTX-M associated with healthcare. We studied a collection of 12 strains of extraintestinal E. coli with diminished sensitivity to broad-spectrum cephalosporins. Antimicrobial susceptibility was determined by minimum inhibitory concentration. We determined the phylogenetic groups, virulence factors and genes encoding antimicrobial resistance using PCR, and clonal characterization by repetitive element palindromic-PCR rep-PCR. All strains showed resistance to cephalosporins and joint resistance to quinolones and aminoglycosides. The phylogenetic distribution showed that the A and B1 groups were the most frequent, followed by D and B2. We found all the virulence factors analyzed in the B2 group, and fimH gene was the most frequent among them. We found blaCTX-M in all strains,with a higher prevalence of blaCTX-M-8; two of these strains showed coproduction of blaCTX-M-9 and were genetically identified as blaCTXM-65 and blaCTX-M-147 by sequencing. The strains under study showed genetic diversity, hosting a variety of virulence genes, as well as antimicrobial resistance with no particular phylogroup prevalence. This is the first report of blaCTX-M alleles in Venezuela and in the world associated to non-genetically related strains isolated in health care units, a situation that deserves attention, as well as the rationalization of antimicrobials use.

Bacillus amyloliquefaciens TSBSO 3.8, a biosurfactant-producing strain with biotechnological potential for microbial enhanced oil recovery.

Science.gov (United States)

Alvarez, Vanessa Marques; Jurelevicius, Diogo; Marques, Joana Montezano; de Souza, Pamella Macedo; de Araújo, Livia Vieira; Barros, Thalita Gonçalves; de Souza, Rodrigo Octavio Mendonça Alves; Freire, Denise Maria Guimarães; Seldin, Lucy

2015-12-01

A screening for biosurfactant-producing bacteria was conducted with 217 strains that were isolated from environmental samples contaminated with crude oil and/or petroleum derivatives. Although 19 promising biosurfactant producers were detected, strain TSBSO 3.8, which was identified by molecular methods as Bacillus amyloliquefaciens, drew attention for its production of a high-activity compound that presented an emulsification activity of 63% and considerably decreased surface (28.5 mN/m) and interfacial (11.4 mN/m) tensions in Trypticase Soy Broth culture medium. TSBSO 3.8 growth and biosurfactant production were tested under different physical and chemical conditions to evaluate its biotechnological potential. Biosurfactant production occurred between 0.5% and 7% NaCl, at pH values varying from 6 to 9 and temperatures ranging from 28 to 50 °C. Moreover, biosurfactant properties remained the same after autoclaving at 121 °C for 15 min. The biosurfactant was also successful in a test to simulate microbial enhanced oil recovery (MEOR). Mass spectrometry analysis showed that the surface active compound was a surfactin, known as a powerful biosurfactant that is commonly produced by Bacillus species. The production of a high-efficiency biosurfactant, under some physical and chemical conditions that resemble those experienced in an oil production reservoir, such as high salinities and temperatures, makes TSBSO 3.8 an excellent candidate and creates good expectations for its application in MEOR. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of γ-Aminobutyric Acid-producing Lactobacillus Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress.

Science.gov (United States)

Zhu, Y Z; Cheng, J L; Ren, M; Yin, L; Piao, X S

2015-07-01

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (pGABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (plevel was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

A hydrogen-producing, hydrogenase-free mutant strain of Nostoc punctiforme ATCC 29133

Energy Technology Data Exchange (ETDEWEB)

Lindberg, P.; Lindblad, P. [Uppsala Univ. (Sweden). Dept. of Physiological Botany; Schuetz, K.; Happe, T. [Universitaet Bonn (Germany). Botanisches Inst.

2002-12-01

The hupL gene, encoding the uptake hydrogenase large subunit, in Nostoc sp. strain ATCC 29133, a strain lacking a bidirectional hydrogenase, was inactivated by insertional mutagenesis. Recombinant strains were isolated and analysed, and one hupL{sup -} strain, NHM5, was selected for further study. Cultures of NHM5 were grown under nitrogen-fixing conditions and H{sub 2} evolution under air was observed using an H{sub 2} electrode. (Author)

Mechanism of action of clostridial glycine reductase: Isolation and characterization of a covalent acetyl enzyme intermediate

International Nuclear Information System (INIS)

Arkowitz, R.A.; Abeles, R.H.

1991-01-01

Clostridial glycine reductase consists of proteins A, B, and C and catalyzes the reaction glycine + P i + 2e - → acetyl phosphate + NH 4 + . Evidence was previously obtained that is consistent with the involvement of an acyl enzyme intermediate in this reaction. The authors now demonstrate that protein C catalyzes exchange of [ 32 P]P i into acetyl phosphate, providing additional support for an acetyl enzyme intermediate on protein C. Furthermore, they have isolated acetyl protein C and shown that it is qualitatively, catalytically competent. Acetyl protein C can be obtained through the forward reaction from protein C and Se-(carboxymethyl)selenocysteine-protein A, which is generated by the reaction of glycine with proteins A and B. Acetyl protein C can also be generated through the reverse reaction by the addition of acetyl phosphate to protein C. Both procedures lead to the same acetyl enzyme. The acetyl enzyme reacts with P i to give acetyl phosphate. When [ 14 C]acetyl protein C is denaturated with TCA and redissolved with urea, radioactivity remained associated with the protein. Treatment with KBH 4 removes all the radioactivity associated with protein C, resulting in the formation of [ 14 C]ethanol. They conclude that a thiol group on protein C is acetylated. Proteins A and C together catalyze the exchange of tritium atoms from [ 3 H]H 2 O into acetyl phosphate. This exchange reaction supports the proposal that an enol of the acetyl enzyme is an intermediate in the reaction sequence

Comparative evaluation of the Ridascreen Verotoxin enzyme immunoassay for detection of Shiga-toxin producing strains of Escherichia coli (STEC) from food and other sources.

Science.gov (United States)

Beutin, L; Steinrück, H; Krause, G; Steege, K; Haby, S; Hultsch, G; Appel, B

2007-03-01

To evaluate the suitability of the commercially distributed Ridascreen Verotoxin enzyme immunoassay (EIA) for detection of known genetic types of the Vero (Shiga) toxins 1 (Stx1) and 2 (Stx2) families and to determine its relative sensitivity and specificity. The Ridascreen-EIA was compared with the Vero cell assay, a P(1)-glycoprotein receptor EIA and with stx gene-specific PCs for detection of Stx with 43 Shiga toxin-producing strains of Escherichia coli (STEC) reference strains and with 241 test strains. The Ridascreen-EIA detects strains producing Stx1 and variants Stx1c and Stx1d, as well as Stx2 and variants Stx2d1, Stx2d2, Stx2e, Stx2d, Stx2-O118 (Stx2d-ount), Stx2-NV206, Stx2f and Stx2g. The assay showed a relative sensitivity of 95.7% and a relative specificity of 98.7%. Some of the Stx2-O118-, Stx2e- and Stx2g-producing STEC were not detected with the Ridascreen-EIA probably because of low amount of toxin produced by these strains. The Ridascreen-EIA is able to detect all known types of Stx and is applicable for routine screening of bacterial isolates owing to its high specificity. It is less applicable for testing samples where low amounts of Stx are expected, such as mixed cultures and certain Stx2 variants. This study presents a first comprehensive evaluation of the Ridascreen-EIA, a rapid standardized STEC screening test for routine diagnostic laboratories. Data are presented on the type of the spectrum of Stx that are detected with this immunoassay and its advantages and limits for practical use.

Identification and Funtional Characterization of Three Postsynaptic Short-chain Neurotoxins from Hydrophiinae, Lapemis hardwickii Gray.

Science.gov (United States)

Zhong, Xiao-Fen; Peng, Li-Sheng; Wu, Wen-Yan; Wei, Jian-Wen; Yang, Hong; Yang, Yan-Zhen; Xu, An-Long

2001-01-01

Three cDNA clones, sn12, sn36 and sn160, encoding isoforms of postsynaptic short-chain neurotoxins, were cloned by screening a cDNA library of the venom from Hydrophiinae, Lapemis hardwickii Gray. The sequences of three cDNA clones encoded proteins consisting of 60 amino acid residues. There was only one amino acid substitution among the three isoforms SN12, SN36 and SN160 at the position 46 of mature proteins, and they were Pro(46), His(46) and Arg(46), respectively. The three molecules were expressed in Escherichia coli and the recombinant proteins were characterized. Different LD(50) were obtained, namely 0.0956 mg/kg, 0.3467 mg/kg and 0.2192 mg/kg, when the SN12, SN36 and SN160 were injected into Kunming mice(i.p.). In analgesic effect assayed by the acetic acid-induced writhing method, SN12 and SN160 showed similar analgesic effect, but SN36 had effects significantly different with the other two. Our studies suggested that the amino acid residues on position 46 could affect the combination between the postsynaptic short-chain neurotoxins and the nicotinic acetylchoine receptor, since different amino acid substitution resulted in different biological activities.

Screening and Evaluation of Polyhydroxybutyrate-Producing Strains from Indigenous Isolate Cupriavidus taiwanensis Strains

Directory of Open Access Journals (Sweden)

Om-Murugan Janarthanan

2011-01-01

Full Text Available Polyhydroxyalkanoate (PHA is a biodegradable material with many potential biomedical applications, including medical implants and drug delivery. This study developed a system for screening production strains in order to optimize PHA production in Cupriavidus taiwanensis 184, 185, 186, 187, 204, 208, 209 and Pseudomona oleovorans ATCC 29347. In this study, Sudan black B staining, Infrared (IR and Gas Chromatography (GC analysis indicated that the best strain for PHA synthesis is C. taiwanensis 184, which obtains polyhydroxybutyrate (PHB. Cultivation of C. taiwanensis 184 under a pH of 7.0, at 30 °C, and at an agitation rate of 200 rpm, obtained a PHB content of 10% and PHB production of 0.14 g/L. The carbon and nitrogen types selected for analysis of PHB production by C. taiwanensis 184 were gluconic acid and NH4Cl, respectively. Optimal carbon/nitrogen ratio for PHB production was also determined. This study demonstrated a PHB content of 58.81% and a PHB production of 2.44 g/L when the carbon/nitrogen ratio of 8/1 was selected for C. taiwanensis 184. A two‑stage fermentation strategy significantly enhanced PHB content and PHB production. Under a two-stage fermentation strategy with nutrient‑limited conditions, C. taiwanensis 184 obtained a PHB content of 72% and a PHB concentration of 7 g/L. Finally, experimental results confirmed that optimizing the growth medium and fermentation conditions for cultivating the indigenous C. taiwanensis 184 strain substantially elevated PHB content from 10% to 72% and PHB production from 0.14 g/L to 7 g/L, respectively.

Different response to acetic acid stress in Saccharomyces cerevisiae wild-type and l-ascorbic acid-producing strains.

Science.gov (United States)

Martani, Francesca; Fossati, Tiziana; Posteri, Riccardo; Signori, Lorenzo; Porro, Danilo; Branduardi, Paola

2013-09-01

Biotechnological processes are of increasing significance for industrial production of fine and bulk chemicals, including biofuels. Unfortunately, under operative conditions microorganisms meet multiple stresses, such as non-optimal pH, temperature, oxygenation and osmotic stress. Moreover, they have to face inhibitory compounds released during the pretreatment of lignocellulosic biomasses, which constitute the preferential substrate for second-generation processes. Inhibitors include furan derivatives, phenolic compounds and weak organic acids, among which acetic acid is one of the most abundant and detrimental for cells. They impair cellular metabolism and growth, reducing the productivity of the process: therefore, the development of robust cell factories with improved production rates and resistance is of crucial importance. Here we show that a yeast strain engineered to endogenously produce vitamin C exhibits an increased tolerance compared to the parental strain when exposed to acetic acid at moderately toxic concentrations, measured as viability on plates. Starting from this evidence, we investigated more deeply: (a) the nature and levels of reactive oxygen species (ROS); (b) the activation of enzymes that act directly as detoxifiers of reactive oxygen species, such as superoxide dismutase (SOD) and catalase, in parental and engineered strains during acetic acid stress. The data indicate that the engineered strain can better recover from stress by limiting ROS accumulation, independently from SOD activation. The engineered yeast can be proposed as a model for further investigating direct and indirect mechanism(s) by which an antioxidant can rescue cells from organic acid damage; moreover, these studies will possibly provide additional targets for further strain improvements. Copyright © 2013 John Wiley & Sons, Ltd.

Integrative Gene Cloning and Expression System for Streptomyces sp. US 24 and Streptomyces sp. TN 58 Bioactive Molecule Producing Strains

Directory of Open Access Journals (Sweden)

Samiha Sioud

2009-01-01

Full Text Available Streptomyces sp. US 24 and Streptomyces sp. TN 58, two strains producing interesting bioactive molecules, were successfully transformed using E. coli ET12567 (pUZ8002, as a conjugal donor, carrying the integrative plasmid pSET152. For the Streptomyces sp. US 24 strain, two copies of this plasmid were tandemly integrated in the chromosome, whereas for Streptomyces sp. TN 58, the integration was in single copy at the attB site. Plasmid pSET152 was inherited every time for all analysed Streptomyces sp. US 24 and Streptomyces sp. TN 58 exconjugants under nonselective conditions. The growth, morphological differentiation, and active molecules production of all studied pSET152 integrated exconjugants were identical to those of wild type strains. Consequently, conjugal transfer using pSET152 integration system is a suitable means of genes transfer and expression for both studied strains. To validate the above gene transfer system, the glucose isomerase gene (xylA from Streptomyces sp. SK was expressed in strain Streptomyces sp. TN 58. Obtained results indicated that heterologous glucose isomerase could be expressed and folded effectively. Glucose isomerase activity of the constructed TN 58 recombinant strain is of about eighteenfold higher than that of the Streptomyces sp. SK strain. Such results are certainly of importance due to the potential use of improved strains in biotechnological process for the production of high-fructose syrup from starch.

Genetic characterization of Shiga toxin-producing Escherichia coli O26:H11 strains isolated from animal, food, and clinical samples

Science.gov (United States)

Krüger, Alejandra; Lucchesi, Paula M. A.; Sanso, A. Mariel; Etcheverría, Analía I.; Bustamante, Ana V.; Burgán, Julia; Fernández, Luciana; Fernández, Daniel; Leotta, Gerardo; Friedrich, Alexander W.; Padola, Nora L.; Rossen, John W. A.

2015-01-01

The Shiga-toxin producing Escherichia coli (STEC) may cause serious illness in human. Here we analyze O26:H11 strains known to be among the most reported STEC strains causing human infections. Genetic characterization of strains isolated from animal, food, and clinical specimens in Argentina showed that most carried either stx1a or stx2a subtypes. Interestingly, stx2a-positive O26:H11 rarely isolated from cattle in other countries showed to be an important proportion of O26:H11 strains circulating in cattle and food in our region. Seventeen percent of the isolates harbored more than one gene associated with antimicrobial resistance. In addition to stx, all strains contained the virulence genes eae-β, tir, efa, iha, espB, cif, espA, espF, espJ, nleA, nleB, nleC, and iss; and all except one contained ehxA, espP, and cba genes. On the other hand, toxB and espI genes were exclusively observed in stx2-positive isolates, whereas katP was only found in stx1a-positive isolates. Our results show that O26:H11 STEC strains circulating in Argentina, including those isolated from humans, cattle, and meat products, present a high pathogenic potential, and evidence that cattle can be a reservoir of O26:H11 strains harboring stx2a. PMID:26539413

Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

Science.gov (United States)

Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

2016-01-01

Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae. Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

Comparison of the virulence of exopolysaccharide-producing Prevotella intermedia to exopolysaccharide non-producing periodontopathic organisms.

Science.gov (United States)

Yamanaka, Takeshi; Yamane, Kazuyoshi; Furukawa, Tomoyo; Matsumoto-Mashimo, Chiho; Sugimori, Chieko; Nambu, Takayuki; Obata, Noboru; Walker, Clay B; Leung, Kai-Poon; Fukushima, Hisanori

2011-08-25

Evidence in the literature suggests that exopolysaccharides (EPS) produced by bacterial cells are essential for the expression of virulence in these organisms. Secreted EPSs form the framework in which microbial biofilms are built. This study evaluates the role of EPS in Prevotella intermedia for the expression of virulence. This evaluation was accomplished by comparing EPS-producing P. intermedia strains 17 and OD1-16 with non-producing P. intermedia ATCC 25611 and Porphyromonas gingivalis strains ATCC 33277, 381 and W83 for their ability to induce abscess formation in mice and evade phagocytosis. EPS-producing P. intermedia strains 17 and OD1-16 induced highly noticeable abscess lesions in mice at 107 colony-forming units (CFU). In comparison, P. intermedia ATCC 25611 and P. gingivalis ATCC 33277, 381 and W83, which all lacked the ability to produce viscous materials, required 100-fold more bacteria (109 CFU) in order to induce detectable abscess lesions in mice. Regarding antiphagocytic activity, P. intermedia strains 17 and OD1-16 were rarely internalized by human polymorphonuclear leukocytes, but other strains were readily engulfed and detected in the phagosomes of these phagocytes. These results demonstrate that the production of EPS by P. intermedia strains 17 and OD1-16 could contribute to the pathogenicity of this organism by conferring their ability to evade the host's innate defence response.

Case of Meningitis in a Neonate Caused by an Extended-Spectrum-Beta-Lactamase-Producing Strain of Hypervirulent Klebsiella pneumoniae

Directory of Open Access Journals (Sweden)

Khalit S. Khaertynov

2017-08-01

Full Text Available Klebsiella pneumoniae is one of the most important infectious agents among neonates. This pathogen has a potential to develop an increased antimicrobial resistance and virulence. The classic non-virulent strain of K. pneumoniae, producing an extended-spectrum beta-lactamases (ESBL, is associated with nosocomial infection mainly in preterm neonates. Hypervirulent K. pneumoniae strains are associated with invasive infection among previously healthy ambulatory patients, and most of them exhibit antimicrobial susceptibility. During the last few years, several cases of diseases caused by hypervirulent K. pneumoniae producing ESBL have been registered in different geographical regions of the world. However, reports of such cases in neonates are rare. Here, we reported that this pathogen can cause pyogenic meningitis in full-term neonate with poor prognosis. A previously healthy, full-term, 12-day-old neonate was admitted to the infectious diseases hospital with suspected meningitis. The clinical symptoms included loss of appetite, irritability, fever, seizures, and a bulging anterior fontanelle. The analysis of the cerebrospinal fluid confirmed the diagnosis of meningitis. Blood and cerebrospinal fluid cultures were positive for K. pneumoniae, producing ESBL. K. pneumoniae isolates were resistant to aminopenicillins, 3rd generation cephalosporins but were sensitive to imipenem and meropenem. The “string test” was positive. The study of the virulence factors of K. pneumoniae by PCR revealed the presence of the rmpA gene. A combination of K. pneumoniae virulence and drug resistance complicated by cerebral oedema led to the death of the neonate. We concluded that both the risk of developing severe forms of infection and the outcome of the disease due to K. pneumonia are associated with the phenotypic features of the pathogen such as its antibiotic susceptibility and virulence factors. Emergence of the ESBL-producing strain of hypervirulent K

Recent advances in botulinum neurotoxin inhibitor development.

Science.gov (United States)

Kiris, Erkan; Burnett, James C; Kane, Christopher D; Bavari, Sina

2014-01-01

Botulinum neurotoxins (BoNTs) are endopeptidases that target motor neurons and block acetylcholine neurotransmitter release. This action results in the muscle paralysis that defines the disease botulism. To date, there are no FDA-approved therapeutics to treat BoNT-mediated paralysis after intoxication of the motor neuron. Importantly, the rationale for pursuing treatments to counter these toxins is driven by their potential misuse. Current drug discovery efforts have mainly focused on small molecules, peptides, and peptidomimetics that can directly and competitively inhibit BoNT light chain proteolytic activity. Although this is a rational approach, direct inhibition of the Zn(2+) metalloprotease activity has been elusive as demonstrated by the dearth of candidates undergoing clinical evaluation. Therefore, broadening the scope of viable targets beyond that of active site protease inhibitors represents an additional strategy that could move the field closer to the clinic. Here we review the rationale, and discuss the outcomes of earlier approaches and highlight potential new targets for BoNT inhibition. These include BoNT uptake and processing inhibitors, enzymatic inhibitors, and modulators of neuronal processes associated with toxin clearance, neurotransmitter potentiation, and other pathways geared towards neuronal recovery and repair.

Botulinum neurotoxin: a marvel of protein design.

Science.gov (United States)

Montal, Mauricio

2010-01-01

Botulinum neurotoxin (BoNT), the causative agent of botulism, is acknowledged to be the most poisonous protein known. BoNT proteases disable synaptic vesicle exocytosis by cleaving their cytosolic SNARE (soluble NSF attachment protein receptor) substrates. BoNT is a modular nanomachine: an N-terminal Zn(2+)-metalloprotease, which cleaves the SNAREs; a central helical protein-conducting channel, which chaperones the protease across endosomes; and a C-terminal receptor-binding module, consisting of two subdomains that determine target specificity by binding to a ganglioside and a protein receptor on the cell surface and triggering endocytosis. For BoNT, functional complexity emerges from its modular design and the tight interplay between its component modules--a partnership with consequences that surpass the simple sum of the individual component's action. BoNTs exploit this design at each step of the intoxication process, thereby achieving an exquisite toxicity. This review summarizes current knowledge on the structure of individual modules and presents mechanistic insights into how this protein machine evolved to this level of sophistication. Understanding the design principles underpinning the function of such a dynamic modular protein remains a challenging task.

Genome Sequence Analysis of the Biogenic Amine-Producing Strain Lactococcus lactis subsp. cremoris CECT 8666 (Formerly GE2-14)

Science.gov (United States)

del Rio, Beatriz; Linares, Daniel M.; Fernandez, Maria; Mayo, Baltasar; Martin, M. Cruz; Alvarez, Miguel A.

2014-01-01

We here report a 2,801,031-bp annotated draft assembly for the Lactococcus lactis subsp. cremoris GE2-14 genome. This dairy strain produces the biogenic amine putrescine. This sequence may help identify the mechanisms regulating putrescine biosynthesis and throw light on ways to reduce its presence in fermented foods. PMID:25342694

Bacteriocin producers from traditional food products

Directory of Open Access Journals (Sweden)

Thonart P.

2007-01-01

Full Text Available A total of 220 strains of LAB isolated from 32 samples of traditional fermented food from Senegal were screened for bacteriocin production. Two bacteriocin producers, Lactococcus lactis subsp. lactis and Enterococcus faecium, were identified from 12 bacteriocin-producing isolates on the basis of phenotypic analyses and 16S rDNA sequence. Both bacteriocins produced by new isolates show antimicrobial activity against Listeria monocytogenes and Bacillus coagulans whereas only that produced by Lactococcus lactis has an activity against Bacillus cereus. Bacteriocin-producing Lactococcus lactis strains were found in a variety of traditional foods indicating a high potential of growth of this strain in variable ecological complex environment. Partial 16S rDNA of the two bacteriocin producers obtained in this study has been registered to Genbank databases under the accession number AY971748 for Lactococcus lactis subsp. lactis (named CWBI-B1410 and AY971749 for Enterococcus faecium (named CWBI-B1411. The new bacteriocin-producing Lactococcus lactis subsp. lactis strain has been selected for identification and application of the bacteriocin to food preservation.

Involvement of Cholinergic and Adrenergic Receptors in Pathogenesis and Inflammatory Response Induced by Alpha-Neurotoxin Bot III of Scorpion Venom.

Science.gov (United States)

Nakib, Imene; Martin-Eauclaire, Marie-France; Laraba-Djebari, Fatima

2016-10-01

Bot III neurotoxin is the most lethal α neurotoxin purified from Buthus occitanus tunetanus scorpion venom. This toxin binds to the voltage-gated sodium channel of excitable cells and blocks its inactivation, inducing an increased release of neurotransmitters (acetylcholine and catecholamines). This study aims to elucidate the involvement of cholinergic and adrenergic receptors in pathogenesis and inflammatory response triggered by this toxin. Injection of Bot III to animals induces an increase of peroxidase activities, an imbalance of oxidative status, tissue damages in lung parenchyma, and myocardium correlated with metabolic disorders. The pretreatment with nicotine (nicotinic receptor agonist) or atropine (muscarinic receptor antagonist) protected the animals from almost all disorders caused by Bot III toxin, especially the immunological alterations. Bisoprolol administration (selective β1 adrenergic receptor antagonist) was also efficient in the protection of animals, mainly on tissue damage. Propranolol (non-selective adrenergic receptor antagonist) showed less effect. These results suggest that both cholinergic and adrenergic receptors are activated in the cardiopulmonary manifestations induced by Bot III. Indeed, the muscarinic receptor appears to be more involved than the nicotinic one, and the β1 adrenergic receptor seems to dominate the β2 receptor. These results showed also that the activation of nicotinic receptor leads to a significant protection of animals against Bot III toxin effect. These findings supply a supplementary data leading to better understanding of the mechanism triggered by scorpionic neurotoxins and suggest the use of drugs targeting these receptors, especially the nicotinic one in order to counteract the inflammatory response observed in scorpion envenomation.

Botulinum Neurotoxins

Science.gov (United States)

2012-03-28

significant threat was realized (Parker, 2002). Wein and Liu published a mathematical model to predict the effects of the deliberate introduction of...12, pp. 794-805, ISSN 1554-8600 Ryan, C.A., Nickels, M.K. & Hargrett, N.T. et al. (1987). Massive outbreak of antimicrobial resistant salmonellosis...200,000 people were infected with an antibiotic- resistant strain of Salmonella caused by an inadvertent contamination at a single northern Illinois dairy

Quantitative analysis of the lactic acid and acetaldehyde produced by Streptococcus thermophilus and Lactobacillus bulgaricus strains isolated from traditional Turkish yogurts using HPLC.

Science.gov (United States)

Gezginc, Y; Topcal, F; Comertpay, S; Akyol, I

2015-03-01

The present study was conducted to evaluate the lactic acid- and acetaldehyde-producing abilities of lactic acid bacterial species isolated from traditionally manufactured Turkish yogurts using HPLC. The lactic acid bacterial species purified from the yogurts were the 2 most widely used species in industrial yogurt production: Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria have the ability to ferment hexose sugars homofermentatively to generate lactic acid and some carbonyl compounds, such as acetaldehyde through pyruvate metabolism. The levels of the compounds produced during fermentation influence the texture and the flavor of the yogurt and are themselves influenced by the chemical composition of the milk, processing conditions, and the metabolic activity of the starter culture. In the study, morphological, biochemical, and molecular characteristics were employed to identify the bacteria obtained from homemade yogurts produced in different regions of Turkey. A collection of 91 Strep. thermophilus and 35 L. bulgaricus strains were investigated for their lactic acid- and acetaldehyde-formation capabilities in various media such as cow milk, LM17 agar, and aerobic-anaerobic SM17 agar or de Man, Rogosa, and Sharpe agar. The amounts of the metabolites generated by each strain in all conditions were quantified by HPLC. The levels were found to vary depending on the species, the strain, and the growth conditions used. Whereas lactic acid production ranged between 0 and 77.9 mg/kg for Strep. thermophilus strains, it ranged from 0 to 103.5 mg/kg for L. bulgaricus. Correspondingly, the ability to generate acetaldehyde ranged from 0 to 105.9 mg/kg in Strep. thermophilus and from 0 to 126.9 mg/kg in L. bulgaricus. Our study constitutes the first attempt to determine characteristics of the wild strains isolated from traditional Turkish yogurts, and the approach presented here, which reveals the differences in metabolite production abilities of the

Characterization of Clostridium Baratii Type F Strains Responsible for an Outbreak of Botulism Linked to Beef Meat Consumption in France.

Science.gov (United States)

Mazuet, Christelle; Legeay, Christine; Sautereau, Jean; Bouchier, Christiane; Criscuolo, Alexis; Bouvet, Philippe; Trehard, Hélène; Jourdan Da Silva, Nathalie; Popoff, Michel

2017-02-01

A second botulism outbreak due to Clostridium baratii occurred in France in August 2015 and included three patients who had their meal in a restaurant the same day. We report the characterization of C. baratii isolates including whole genome sequencing (WGS). Four C. baratii isolates collected in August 2015 from the outbreak 2 were analysed for toxin production and typing as well as for genetic characterization. WGS was done using using the NEBNext Ultra DNA Library Prep kit for Illumina (New England Biolabs) and sequenced on MiSeq machine (Illumina) in paired-end reads of 250 bases. The phylogenetic tree was generated based on the UPGMA method with genetic distances computed by using the Kimura two-parameter model. Evolutionary analyses were conducted in Bionumerics (V.6.6 Applied Maths). Three C. baratii isolates for patient's stools and one isolate from meat produced botulinum neurotoxin (BoNT) type F and retained a bont/F7 gene in OrfX cluster. All isolates were identical according to the WGS. However, phylogeny of the core genome showed that the four C. baratii strains were distantly related to that of the previous C. baratii outbreak in France in 2014 and from the other C. baratii strains reported in databanks. The fact that the strains isolated from the patients and meat samples were genetically identical supports that the meat used for the Bolognese sauce was responsible for this second botulism outbreak in France. These isolates were unrelated to that from the first C. baratii outbreak in France in 2014 indicating a distinct source of contamination. WGS provided robust determination of genetic relatedness and information regarding BoNT typing and toxin gene locus genomic localization.

The first venomous crustacean revealed by transcriptomics and functional morphology: remipede venom glands express a unique toxin cocktail dominated by enzymes and a neurotoxin.

Science.gov (United States)

von Reumont, Björn M; Blanke, Alexander; Richter, Sandy; Alvarez, Fernando; Bleidorn, Christoph; Jenner, Ronald A

2014-01-01

Animal venoms have evolved many times. Venomous species are especially common in three of the four main groups of arthropods (Chelicerata, Myriapoda, and Hexapoda), which together represent tens of thousands of species of venomous spiders, scorpions, centipedes, and hymenopterans. Surprisingly, despite their great diversity of body plans, there is no unambiguous evidence that any crustacean is venomous. We provide the first conclusive evidence that the aquatic, blind, and cave-dwelling remipede crustaceans are venomous and that venoms evolved in all four major arthropod groups. We produced a three-dimensional reconstruction of the venom delivery apparatus of the remipede Speleonectes tulumensis, showing that remipedes can inject venom in a controlled manner. A transcriptomic profile of its venom glands shows that they express a unique cocktail of transcripts coding for known venom toxins, including a diversity of enzymes and a probable paralytic neurotoxin very similar to one described from spider venom. We screened a transcriptomic library obtained from whole animals and identified a nontoxin paralog of the remipede neurotoxin that is not expressed in the venom glands. This allowed us to reconstruct its probable evolutionary origin and underlines the importance of incorporating data derived from nonvenom gland tissue to elucidate the evolution of candidate venom proteins. This first glimpse into the venom of a crustacean and primitively aquatic arthropod reveals conspicuous differences from the venoms of other predatory arthropods such as centipedes, scorpions, and spiders and contributes valuable information for ultimately disentangling the many factors shaping the biology and evolution of venoms and venomous species.

Arabidopsis thaliana defense response to the ochratoxin A-producing strain (Aspergillus ochraceus 3.4412).

Science.gov (United States)

Hao, Junran; Wu, Weihong; Wang, Yan; Yang, Zhuojun; Liu, Yang; Lv, Yangjun; Zhai, Yanan; Yang, Jing; Liang, Zhihong; Huang, Kunlun; Xu, Wentao

2015-05-01

OTA-producing strain Aspergillus ochraceus induced necrotic lesions, ROS accumulation and defense responses in Arabidopsis . Primary metabolic and defense-related proteins changed in proteomics. Ascorbate-glutathione cycle and voltage-dependent anion-selective channel proteins fluctuated. Mycotoxigenic fungi, as widespread contaminants by synthesizing mycotoxins in pre-/post-harvest infected plants and even stored commercial cereals, could usually induce plant-fungi defense responses. Notably, ochratoxin A (OTA) is a nephrotoxic, hepatotoxic, teratogenic, immunotoxic and phytotoxic mycotoxin. Herein, defense responses of model system Arabidopsis thaliana detached leaves to infection of Aspergillus ochraceus 3.4412, an OTA high-producing strain, were studied from physiological, proteomic and transcriptional perspectives. During the first 72 h after inoculation (hai), the newly formed hypersensitive responses-like lesions, decreased chlorophyll content, accumulated reactive oxygen species and upregulated defense genes expressions indicated the defense response was induced in the leaves with the possible earlier motivated jasmonic acid/ethylene signaling pathways and the later salicylic acid-related pathway. Moreover, proteomics using two-dimensional gel electrophoresis 72 hai showed 16 spots with significantly changed abundance and 13 spots corresponding to 12 unique proteins were successfully identified by MALDI-TOF/TOF MS/MS. Of these, six proteins were involved in basic metabolism and four in defense-related processes, which included glutathione-S-transferase F7, voltage-dependent anion-selective channel protein 3 (VDAC-3), osmotin-like protein OSM34 and blue copper-binding protein. Verified from proteomic and/or transcriptional perspectives, it is concluded that the primary metabolic pathways were suppressed with the ascorbate-glutathione cycle fluctuated in response to A. ochraceus and the modulation of VDACs suggested the possibility of structural damage and

Multiagent vaccines vectored by Venezuelan equine encephalitis virus replicon elicits immune responses to Marburg virus and protection against anthrax and botulinum neurotoxin in mice.

Science.gov (United States)

Lee, John S; Groebner, Jennifer L; Hadjipanayis, Angela G; Negley, Diane L; Schmaljohn, Alan L; Welkos, Susan L; Smith, Leonard A; Smith, Jonathan F

2006-11-17

The development of multiagent vaccines offers the advantage of eliciting protection against multiple diseases with minimal inoculations over a shorter time span. We report here the results of using formulations of individual Venezuelan equine encephalitis (VEE) virus replicon-vectored vaccines against a bacterial disease, anthrax; a viral disease, Marburg fever; and against a toxin-mediated disease, botulism. The individual VEE replicon particles (VRP) expressed mature 83-kDa protective antigen (MAT-PA) from Bacillus anthracis, the glycoprotein (GP) from Marburg virus (MBGV), or the H(C) fragment from botulinum neurotoxin (BoNT H(C)). CBA/J mice inoculated with a mixture of VRP expressing BoNT H(C) serotype C (BoNT/C H(C)) and MAT-PA were 80% protected from a B. anthracis (Sterne strain) challenge and then 100% protected from a sequential BoNT/C challenge. Swiss mice inoculated with individual VRP or with mixtures of VRP vaccines expressing BoNT H(C) serotype A (BoNT/A H(C)), MAT-PA, and MBGV-GP produced antibody responses specific to the corresponding replicon-expressed protein. Combination of the different VRP vaccines did not diminish the antibody responses measured for Swiss mice inoculated with formulations of two or three VRP vaccines as compared to mice that received only one VRP vaccine. Swiss mice inoculated with VRP expressing BoNT/A H(C) alone or in combination with VRP expressing MAT-PA and MBGV GP, were completely protected from a BoNT/A challenge. These studies demonstrate the utility of combining individual VRP vaccines into multiagent formulations for eliciting protective immune responses to various types of diseases.

Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

DEFF Research Database (Denmark)

Andersen, Mikael Rørdam; Salazar, Margarita Pena; Schaap, Peter J.

2011-01-01

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme......-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15...

Eosinophil protein X/eosinophil derived neurotoxin (EPX/EDN). Detection by enzyme-linked immunosorbent assay and purification from normal human urine

DEFF Research Database (Denmark)

Reimert, C M; Minuva, U; Kharazmi, A

1991-01-01

Eosinophil protein X/eosinophil derived neurotoxin (EPX/EDN) is one of the cationic proteins found in the granules of the human eosinophilic granulocytes. EPX was purified from extracts of granules isolated from blood buffy coat cells of healthy donors. Polyclonal anti-EPX antibodies were...

Draft genome sequences of Escherichia coli O113:H21 strains recovered from a major produce-production region in California

Science.gov (United States)

Shiga toxin-producing Escherichia coli is a foodborne and waterborne pathogen and is responsible for outbreaks of human gastroenteritis. This report documents the draft genome sequences of seven O113:H21 strains recovered from livestock, wildlife, and soil samples collected in a major agricultural r...

Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains

DEFF Research Database (Denmark)

Frisvad, Jens Christian; Larsen, Thomas Ostenfeld; Thrane, Ulf

2011-01-01

as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were...... examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B(2), B(4), and B(6)) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83......%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also...

Detection and characterization of bacteriocin-producing Lactococcus lactis strains Detecção e caracterização de Lactococcus lactis produtores de bacteriocinas

Directory of Open Access Journals (Sweden)

Izildinha Moreno

1999-04-01

Full Text Available One hundred sixty seven strains of Lactococcus lactis were screened for bacteriocin production by well diffusion assay of GM17 agar. Fourteen (8.4% produced antimicrobial activity other than organic acids, bacteriophages or hydrogen peroxide. The frequency of bacteriocin production ranged from 2% in L. lactis subsp. cremoris up to 12% in L. lactis subsp. lactis. Antimicrobial activities were not observed in any strain of L. lactis subsp. lactis var. diacetylactis. Among thirteen bacteriocin-producing strains and two nisin-producing strains (L. lactis subsp. lactis ATCC 11454 and L. lactis subsp. lactis CNRZ 150, eight (53% were characterized as lactose-positive (Lac+ and proteinase-negative (Prt-. The bacteriocin-producing cultures were also characterized on the basis of plasmid content. All strains had 2 to 7 plasmids with molecular weights varying from 0.5 to 28.1 Mdal. Four strains (ITAL 435, ITAL 436, ITAL 437 and ITAL 438 showed identical profiles and the other were quite distinct.Um total de 167 linhagens de L. lactis foi selecionado para os testes de produção de bacteriocinas pelo método de difusão em poços em agar GM17. Desse total, 14 (8.4% produziram substâncias inibidoras que não foram associadas com ácidos orgânicos, peróxido de hidrogênio e bacteriófagos. A frequência de produção de bacteriocinas variou de 2% em L. lactis subsp. cremoris a 12% em L. lactis subsp. lactis. Nenhuma das linhagens de L. lactis subsp. lactis var. diacetylactis produziu substâncias inibidoras. De 13 linhagens produtoras de bacteriocinas e duas de nisina (L. lactis subsp. lactis ATCC 11454 e L. lactis subsp. lactis CNRZ 150, 8 (53% foram caracterizadas como lactose-positivas (Lac+ e proteinase-negativas (Prt-. As linhagens produtoras de bacteriocinas também foram caracterizadas no seu conteúdo de plasmídios. Elas apresentaram de 2 a 7 plasmídios, com pesos moleculares aproximados de 0.5 a 28.1 Mdal. Quatro linhagens (ITAL 435, ITAL 436

The Structure of the Neurotoxin- Associated Protein HA33/A from Clostridium botulinum Suggests a Reoccurring Beta-Trefoil Fold in the Progenitor Toxin Complex

National Research Council Canada - National Science Library

Arndt, Joseph W; Gu, Jenny; Jaroszewski, Lukasz; Schwarzenbacher, Robert; Hanson, Michael A; Lebeda, Frank L; Stevens, Raymond C

2004-01-01

The hemagglutinating protein HA33 from Clostridium botulinum is associated with the large botulinum neurotoxin secreted complexes and is critical in toxin protection, internalization, and possibly activation...

Binding sites and actions of Tx1, a neurotoxin from the venom of the spider Phoneutria nigriventer, in guinea pig ileum

Directory of Open Access Journals (Sweden)

R.G. Santos

1999-12-01

Full Text Available Tx1, a neurotoxin isolated from the venom of the South American spider Phoneutria nigriventer, produces tail elevation, behavioral excitation and spastic paralysis of the hind limbs after intracerebroventricular injection in mice. Since Tx1 contracts isolated guinea pig ileum, we have investigated the effect of this toxin on acetylcholine release, as well as its binding to myenteric plexus-longitudinal muscle membranes from the guinea pig ileum. [125I]-Tx1 binds specifically and with high affinity (Kd = 0.36 ± 0.02 nM to a single, non-interacting (nH = 1.1, low capacity (Bmax 1.1 pmol/mg protein binding site. In competition experiments using several compounds (including ion channel ligands, only PhTx2 and PhTx3 competed with [125I]-Tx1 for specific binding sites (K0.5 apparent = 7.50 x 10-4 g/l and 1.85 x 10-5 g/l, respectively. PhTx2 and PhTx3, fractions from P. nigriventer venom, contain toxins acting on sodium and calcium channels, respectively. However, the neurotoxin PhTx2-6, one of the isoforms found in the PhTx2 pool, did not affect [125I]-Tx1 binding. Tx1 reduced the [3H]-ACh release evoked by the PhTx2 pool by 33%, but did not affect basal or KCl-induced [3H]-ACh release. Based on these results, as well as on the homology of Tx1 with toxins acting on calcium channels (w-Aga IA and IB and its competition with [125I]-w-Cono GVIA in the central nervous system, we suggest that the target site for Tx1 may be calcium channels.

Clostridial collagenase ointment and medicinal honey utilization for pressure ulcers in US hospitals.

Science.gov (United States)

Dreyfus, Jill; Delhougne, Gary; James, Roberta; Gayle, Julie; Waycaster, Curtis

2018-04-01

To describe the utilization of clostridial collagenase ointment (CCO) and medicinal honey debridement methods in real-world inpatient and outpatient hospital settings among pressure ulcer (PU) patients and compare the frequency of healthcare re-encounters between CCO- and medicinal honey-treated patients. De-identified hospital discharge records for patients receiving CCO or medicinal honey methods of debridement and having an ICD-9 code for PU were extracted from the US Premier Healthcare Database. Multivariable analysis was used to compare the frequency of inpatient and outpatient revisits up to 6 months after an index encounter for CCO- vs medicinal honey-treated PUs. The study identified 48,267 inpatients and 2,599 outpatients with PUs treated with CCO or medicinal honeys. Among study inpatients, n = 44,725 (93%) were treated with CCO, and n = 3,542 (7%) with medicinal honeys. CCO and medicinal honeys accounted for 1,826 (70%) and 773 (30%), respectively, of study outpatients. In adjusted models, those treated with CCO had lower odds for inpatient readmissions (OR = 0.86, 95% CI = 0.80-0.94) after inpatient index visits, and outpatient re-encounters both after inpatient (OR = 0.73, 95% CI = 0.67-0.79) and outpatient (OR = 0.78, 95% CI = 0.64-0.95) index visits in 6 months of follow-up. The study was observational in nature, and did not adjust for reasons why patients were hospitalized initially, or why they returned to the facility. Although the study adjusted for differences in a variety of demographic, clinical, and hospital characteristics between the treatments, we are not able to rule out selection bias. Patients with CCO-treated PUs returned to inpatient and outpatient hospital settings less often compared with medicinal honey-treated PUs. These results from real-world administrative data help to gain a better understanding of the clinical characteristics of patients with PUs treated with these two debridement methods and

Selection of RNA Aptamers Against Botulinum Neurotoxin Type A Light Chain Through a Non-Radioactive Approach.

Science.gov (United States)

Chang, Tzuu-Wang; Janardhanan, Pavithra; Mello, Charlene M; Singh, Bal Ram; Cai, Shuowei

2016-09-01

Botulinum neurotoxin (BoNT), a category A agent, is the most toxic molecule known to mankind. The endopeptidase activity of light chain domain of BoNT is the cause for the inhibition of the neurotransmitter release and the flaccid paralysis that leads to lethality in botulism. Currently, antidotes are not available to reverse the flaccid paralysis caused by BoNT. In the present study, a non-radioactive-based systematic evolution of ligands by exponential enrichment (SELEX) process is developed by utilizing surface plasmon resonance to monitor the binding enrichment. Two RNA aptamers have been identified as strong binders against light chain of botulinum neurotoxin type A. These two aptamers showed strong inhibition activity on LCA, with IC50 in nanomolar range. Inhibition kinetic studies reveal mid nanomolar KI and non-competitive nature of their inhibition, suggesting that they have strong potential as antidotes that can reverse the symptom caused by BoNT/A. More importantly, we observed that the 2'-fluorine-pyrimidine-modified RNA aptamers identified here do not change their binding and biological activities. This observation could lead to a cost-effective way for SELEX, by using regular nucleotide during SELEX, and 2'-fluorine-pyrimidine-modified nucleotide for final application to enhance their RNase-resistance.

In vitro detection of cardiotoxins or neurotoxins affecting ion channels or pumps using beating cardiomyocytes as alternative for animal testing

NARCIS (Netherlands)

Nicolas, J.A.Y.; Hendriksen, P.J.M.; Haan, de L.H.J.; Koning, R.; Rietjens, I.M.C.M.; Bovee, T.F.H.

2015-01-01

The present study investigated if and to what extent murine stem cell-derived beating cardiomyocytes within embryoid bodies can be used as a broad screening in vitro assay for neurotoxicity testing, replacing for example in vivo tests for marine neurotoxins. Effect of nine model compounds, acting on

Genome sequences of three tunicamycin-producing Streptomyces strains; S. chartreusis NRRL 12338, S. chartreusis NRRL 3882, and S. lysosuperificus ATCC 31396

Science.gov (United States)

S. chartreusis strains NRRL 12338 and NRRL 3882, S. clavuligerus NRRL 3585, and S. lysosuperificus ATCC 31396, are known producers of tunicamycins, and also of charteusins, clavulinate, cephalosporins, holomycins, and calcimycin. Here we announce the sequencing of the S. lysosuperificus and the two...

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

OpenAIRE

Moran, Yehu; Genikhovich, Grigory; Gordon, Dalia; Wienkoop, Stefanie; Zenkert, Claudia; Özbek, Suat; Technau, Ulrich; Gurevitz, Michael

2011-01-01

Jellyfish, hydras, corals and sea anemones (phylum Cnidaria) are known for their venomous stinging cells, nematocytes, used for prey and defence. Here we show, however, that the potent Type I neurotoxin of the sea anemone Nematostella vectensis, Nv1, is confined to ectodermal gland cells rather than nematocytes. We demonstrate massive Nv1 secretion upon encounter with a crustacean prey. Concomitant discharge of nematocysts probably pierces the prey, expediting toxin penetration. Toxin efficie...

Unusual Δ7,12,19 C35:3 Alkenone Produced by the Mutant Emiliania huxleyi strain CCMP2758 in Culture

Science.gov (United States)

Zheng, Y.; Huang, Y.; Zhang, Y.; Dillon, J. T.

2015-12-01

Alkenones with chain length ranging from C37 to C40 are highly specific biomarkers for certain haptophyte algae in ocean and lake sediments and have been widely used for paleoclimate studies. Short chain alkenones (e.g., C35 and C36) have been found in environmental and culture samples but the origin and structures of these compounds are not fully understood. The benchmark marine alkenone producer, Emiliania huxleyi CCMP2758 strain (the mutant of strain CCMP1742, NEPCC55a) was reported to make 35:2 alkenone when cultured at 15 °C (Prahl et al., 2006). Here we show, when this strain is cultured at lower temperatures (e.g., 4°C), CCMP2758 produces large amount of 35:3 alkenone with unusual double bond positions of Δ7,12,19. We determined the double bond positions of the C35:3 methyl ketonee based on GC-MS analysis of cyclobutylimine derivatives and dimethyl disulfide derivatives respectively, and provide the first temperature calibrations based on the unsaturation ratios of C35 alkenones. Previous studies have found 35:2 alkenone with three methylene interruption in the Black Sea sediment, but it is the first time that an alkenone with a mixed three and five methylene interruption is found. The discovery of short chain alkenones with unusual double bond positions may shed new light to alkenone biosynthesis.

Screening of physiologically active strain of the filamentous fungi - a producer of a complex of lytic enzymes

International Nuclear Information System (INIS)

Kurbatova, E.I.; Sokolova, E.N.; Borshcheva, Yu.A.; Alsivar, S.K.A.; Rimareva, L.V.

2014-01-01

Filamentous Aspergillus fungi were studied to obtain a producer of a complex of the enzymes specific to biodegradation of polymers of cellular walls of vegetable and microbic biomass. Strains were selected by the increased biosynthetic ability in relation to the beta-glucanase (BG), chitinase (CT), mannanase (MN), proteases and pectinases. It was estimated during deep cultivation in the environment containing wheat bran. The fullest complex of hydrolytic enzymes (glucanase, MN, CT, protease and a polygalacturonase (PG)), and also the level of enzymatic activities was in the culture liquid obtained as a result of biosynthesis of Aspergillus foetidus 37-4 (S 37-4) strain. For its cultivation the medium containing salts like potassium dihydrogen phosphate, magnesium sulfate and ammonium sulfate in optimum concentration, and also dioses (maltose, sucrose) and polysaccharides (starch, chitin, pectin) was chosen. The greatest zones of hydrolysis are traced during planting S 37-4 in agar medium containing maltose and low methoxyl citrus pectin. As the synthesis inductor of hemicellulase, MN and CT malt sprouts were used, and of PG - not clarified beet bin fibers. Cultivation was carried out on a thermostatically controlled shaker at 30 deg. C for 120 h. Increase of activity of synthesizable enzymes when using low methoxyl citrus pectin as a media part equaled for BG 5-19%, for PG - 25%, when using a maltose for CT - 100%, MN - 29%. To increase biosynthetic ability of S 37-4 as a mutagen 3-staged ultra-violet radiation (wavelength is 265 nanometers) was applied. The obtained 379-K-5 strain surpassed in activity level a parental strain BG - by 84.8%, CT - by 45.0%, MN - by 62.9%, PG - by 89.0%. The following (4th) stage of radiation led to death of the strain. In comparison with a parental S 37-4 the colony of a mutant strain possessed the bigger size and plentiful formation of an air mycelium, ability to sporogenesis was less expressed

Genomic and Proteomic Characterization of Bacteriocin-Producing Leuconostoc mesenteroides Strains Isolated from Raw Camel Milk in Two Southwest Algerian Arid Zones

Directory of Open Access Journals (Sweden)

Zineb Benmechernene

2014-01-01

Full Text Available Information on the microbiology of camel milk is very limited. In this work, the genetic characterization and proteomic identification of 13 putative producing bacteriocin Leuconostoc strains exhibiting antilisterial activity and isolated from camel milk were performed. DNA sequencing of the 13 selected strains revealed high homology among the 16S rRNA genes for all strains. In addition, 99% homology with Leuconostoc mesenteroides was observed when these sequences were analysed by the BLAST tool against other sequences from reference strains deposited in the Genbank. Furthermore, the isolates were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS which allowed for the identification of 2 mass peaks 6242 m/z and 5118 m/z that resulted to be specific to the species L. mesenteroides. Remarkably, the phyloproteomic tree provided more intraspecific information of L. mesenteroides than phylogenetic analysis. Accordingly, phyloproteomic analysis grouped L. mesenteroides strains into different subbranches, while all L. mesenteroides isolates were grouped in the same branch according to phylogenetic analysis. This study represents, to our knowledge, the first report on the use of MALDI-TOF MS on the identification of LAB isolated from camel milk.

Genomic and proteomic characterization of bacteriocin-producing Leuconostoc mesenteroides strains isolated from raw camel milk in two southwest Algerian arid zones.

Science.gov (United States)

Benmechernene, Zineb; Fernández-No, Inmaculada; Quintela-Baluja, Marcos; Böhme, Karola; Kihal, Mebrouk; Calo-Mata, Pilar; Barros-Velázquez, Jorge

2014-01-01

Information on the microbiology of camel milk is very limited. In this work, the genetic characterization and proteomic identification of 13 putative producing bacteriocin Leuconostoc strains exhibiting antilisterial activity and isolated from camel milk were performed. DNA sequencing of the 13 selected strains revealed high homology among the 16S rRNA genes for all strains. In addition, 99% homology with Leuconostoc mesenteroides was observed when these sequences were analysed by the BLAST tool against other sequences from reference strains deposited in the Genbank. Furthermore, the isolates were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS) which allowed for the identification of 2 mass peaks 6242 m/z and 5118 m/z that resulted to be specific to the species L. mesenteroides. Remarkably, the phyloproteomic tree provided more intraspecific information of L. mesenteroides than phylogenetic analysis. Accordingly, phyloproteomic analysis grouped L. mesenteroides strains into different subbranches, while all L. mesenteroides isolates were grouped in the same branch according to phylogenetic analysis. This study represents, to our knowledge, the first report on the use of MALDI-TOF MS on the identification of LAB isolated from camel milk.

Anti-bacterial Efficacy of Bacteriocin Produced by Marine Bacillus subtilis Against Clinically Important Extended Spectrum Beta-Lactamase Strains and Methicillin-Resistant Staphylococcus aureus

Directory of Open Access Journals (Sweden)

Suresh Mickymaray

2018-02-01

Full Text Available Objective: To investigate the anti-bacterial efficacy of bacteriocin produced by Bacillus subtilis SM01 (GenBank accession no: KY612347, a Gram-positive marine bacterium, against Extended Spectrum Beta-Lactamase (ESBL producing Gram-negative pathogens Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli, and Gram-positive pathogen Methicillin-Resistant Staphylococcus aureus (MRSA. Methods: A marine bacterium was isolated from mangrove sediment from the Red Sea coast of Jeddah, Kingdom of Saudi Arabia, and identified based on its morphological, biochemical, and molecular characteristics. The bacteriocin production using this isolate was carried out in brain heart infusion broth (BHIB medium. The Anti-bacterial activity of bacteriocin was evaluated against selected ESBL strains and MRSA by the well agar method. The effects of incubation time, pH, and temperature on the Anti-bacterial activity were studied. Results: The bacteriocin Bac-SM01 produced by B. subtilis SM01 demonstrated broad-spectrum Anti-bacterial activity against both Gram-negative and -positive bacteria. The present study is the first report that the bacteriocin Bac-SM01 inhibits the growth of ESBL producing Gram-negative strains A. baumannii, P. aeruginosa, and E. coli, and a Gram-positive MRSA strain. The optimum incubation time, pH, and temperature for the Anti-bacterial activity of Bac-SM01 was 24 h, 7, and 37°C respectively. Conclusion: The overall investigation can conclude that the bacteriocin Bac-SM01 from the marine isolate Bacillus subtilis SM01 could be used as an alternative Anti-bacterial agent in pharmaceutical products.

Scorpion neurotoxin AaIT-expressing Beauveria bassiana enhances the virulence against Aedes albopictus mosquitoes.

Science.gov (United States)

Deng, Sheng-Qun; Cai, Qun-Di; Deng, Ming-Zhi; Huang, Qiang; Peng, Hong-Juan

2017-12-01

To improve the insecticidal efficacy of this entomopathogen Beauveria bassiana, the fungus was genetically modified to express an insect-specific scorpion neurotoxin AaIT. The virulence of the recombinant B. bassiana strain (Bb-AaIT) against Aedes albopictus adults (which occurs via penetration through the cuticle during spore germination or by conidia ingestion), and the larvae (by conidia ingestion) was measured with bioassays. The median lethal concentration (LC 50 ) of Bb-AaIT against A. albopictus larvae was 313.3-fold lower on day 4 and 11.3-fold lower on day 10 than that of the wild type (WT). Through conidia feeding or body contact, Bb-AaIT killed 50% of adult female mosquitoes at 3.9- or 1.9-fold reduced concentrations on day 4 and at 2.1- or 2.4-fold reduced concentrations on day 10. Compared with the results for the WT, the median lethal time (LT 50 ) of Bb-AaIT was reduced by 28.6% at 1 × 10 7 conidia ml -1 and 34.3% at 1 × 10 6 conidia ml -1 in the larvae bioassay by conidia ingestion, while it decreased 32.3% at 1 × 10 7 conidia ml -1 by conidia ingestion and 24.2% at 1 × 10 8 conidia ml -1 by penetrating through the cuticle in the adult bioassay. All the differences were significant. Our findings indicated that Bb-AaIT had higher virulence and faster action than the WT in killing the larval and adult mosquitoes, and therefore, it is valuable for development as a commercial mosquito pesticide.

Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains

Science.gov (United States)

Frisvad, Jens C.; Larsen, Thomas O.; Thrane, Ulf; Meijer, Martin; Varga, Janos; Samson, Robert A.; Nielsen, Kristian F.

2011-01-01

Aspergillus niger is perhaps the most important fungus used in biotechnology, and is also one of the most commonly encountered fungi contaminating foods and feedstuffs, and occurring in soil and indoor environments. Many of its industrial applications have been given GRAS status (generally regarded as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B2, B4, and B6) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also produced fumonisins. Strains optimized through random mutagenesis usually maintained their mycotoxin production capability. Toxigenic strains were also able to produce the toxins on media suggested for citric acid production with most of the toxins found in the biomass, thereby questioning the use of the remaining biomass as animal feed. In conclusion it is recommended to use strains of A. niger with inactive or inactivated gene clusters for fumonisins and ochratoxins, or to choose isolates for biotechnological uses in related non-toxigenic species such as A. tubingensis, A. brasiliensis, A vadensis or A. acidus, which neither produce fumonisins nor ochratoxins. PMID:21853139

In Vivo Toxicity and Immunological Characterization of Detoxified Recombinant Botulinum Neurotoxin Type A.

Science.gov (United States)

Ravichandran, Easwaran; Janardhanan, Pavithra; Patel, Kruti; Riding, Stephen; Cai, Shuowei; Singh, Bal Ram

2016-03-01

A double-mutant E224A/E262A full-length botulinum neurotoxin (BoNT) Type A with structural similarity to native BoNT/A but lacking the endopeptidase activity provides an ideal surrogate for testing pharmacokinetics and immunochemical characteristics of BoNT. We determined lethality (LD50) of deactivated recombinant botulinum neurotoxin (drBoNT/A) to be 24.0 μg by intraperitoneal route (i.p). The polypeptide drBoNT/A labeled with near infra-red dye 800 (NIR 800) was used to examine its distribution to different organs using whole body imaging when administered to mice via intravenous (i.v) or i.p route. Also, drBoNT/A was used to evaluate its immunogenicity in Balb/C mice model. drBoNT/A was found to be highly immunogenic when tested under various in vivo conditions in Balb/C mice model. For the first time we have demonstrated that a full length 150 kDa drBoNT/A, by administering via inhalation route in mice model, has evoked both circulating immunoglobulin levels of IgG and secretory IgA at the mucosal surface. The immunoglobulin levels were sufficient enough to protect against the challenge dose of native BoNT toxin in mice model. Tissue distribution of drBoNT/A seems to be similar to that of native toxin. Based on the characteristics described in this report this nontoxic holotoxin protein will assist us to explore the window of opportunity available for therapeutic treatment in case of unnatural poisoning, and also it can be an effective vaccine candidate.

The Metal Neurotoxins: An Important Role in Current Human Neural Epidemics?

Directory of Open Access Journals (Sweden)

Keith Schofield

2017-12-01

Full Text Available Many published studies have illustrated that several of the present day neurological epidemics (autism, attention deficit disorder, Alzheimer’s cannot be correlated to any single neurotoxicant. However, the present scientific examination of the numerous global blood monitoring databases for adults that include the concentrations of the neurotoxic elements, aluminum (Al, arsenic (As, lead (Pb, manganese (Mn, mercury (Hg, and selenium (Se clearly indicate that, when considered in combination, for some, the human body may become easily over-burdened. This can be explained by changes in modern lifestyles. Similar data, solely for pregnant women, have been examined confirming this. All these elements are seen to be present in the human body and at not insignificant magnitudes. Currently suggested minimum risk levels (MRL for humans are discussed and listed together with averages of the reported distributions, together with their spread and maximum values. One observation is that many distributions for pregnant women are not too dissimilar from those of general populations. Women obviously have their individual baseline of neurotoxin values before pregnancy and any efforts to modify this to any significant degree is not yet clearly apparent. For any element, distribution shapes are reasonably similar showing broad distributions with extended tails with numerous outlier values. There are a certain fraction of people that lie well above the MRL values and may be at risk, especially if genetically susceptible. Additionally, synergistic effects between neurotoxins and with other trace metals are now also being reported. It appears prudent for women of child-bearing age to establish their baseline values well before pregnancy. Those at risk then can be better identified. Adequate instrumental testing now is commercially available for this. In addition, directives are necessary for vaccination programs to use only non-neurotoxic adjuvants, especially for

Growth and Survival of Acid-Resistant and Non-Acid-Resistant Shiga-Toxin-Producing Escherichia coli Strains during the Manufacture and Ripening of Camembert Cheese.

Science.gov (United States)

Montet, M P; Jamet, E; Ganet, S; Dizin, M; Miszczycha, S; Dunière, L; Thevenot, D; Vernozy-Rozand, C

2009-01-01

Growth and survival of acid-resistant (AR) and non-acid-resistant (NAR) Shiga-toxin-producing Escherichia coli (STEC) strains were investigated during the manufacture and ripening of microfiltered milk Camembert cheeses. The induction of acid resistance of the STEC strains in cheeses was also studied. Six different mixtures of AR and/or NAR STEC strains were inoculated separately into microfiltered milk at a level of 10(3) CFU mL(-1). The STEC counts (AR and NAR) initially increased by 1 to 2 log(10) CFU g(-1) during cheese-making. Thereafter, the populations stabilized during salting/drying and then decreased during the early stages of ripening. Exposing the STEC strains in artificially inoculated cheeses to simulated gastric fluid (SGF - pH: 2.0) reduced the number of NAR strains to undetectable levels within 40 minutes, versus 120 minutes for the AR STEC strains. AR and NAR STEC were able to survive during the manufacture and ripening of Camembert cheese prepared from microfiltered milk with no evidence of induced acid tolerance in NAR STEC strains.

Growth and Survival of Acid-Resistant and Non-Acid-Resistant Shiga-Toxin-Producing Escherichia coli Strains during the Manufacture and Ripening of Camembert Cheese

Directory of Open Access Journals (Sweden)

M. P. Montet

2009-01-01

Full Text Available Growth and survival of acid-resistant (AR and non-acid-resistant (NAR Shiga-toxin-producing Escherichia coli (STEC strains were investigated during the manufacture and ripening of microfiltered milk Camembert cheeses. The induction of acid resistance of the STEC strains in cheeses was also studied. Six different mixtures of AR and/or NAR STEC strains were inoculated separately into microfiltered milk at a level of 103 CFU mL−1. The STEC counts (AR and NAR initially increased by 1 to 2 log⁡10 CFU g−1 during cheese-making. Thereafter, the populations stabilized during salting/drying and then decreased during the early stages of ripening. Exposing the STEC strains in artificially inoculated cheeses to simulated gastric fluid (SGF - pH: 2.0 reduced the number of NAR strains to undetectable levels within 40 minutes, versus 120 minutes for the AR STEC strains. AR and NAR STEC were able to survive during the manufacture and ripening of Camembert cheese prepared from microfiltered milk with no evidence of induced acid tolerance in NAR STEC strains.

Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology.

Science.gov (United States)

Pirazzini, Marco; Rossetto, Ornella; Eleopra, Roberto; Montecucco, Cesare

2017-04-01

The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects. Novel BoNTs are being discovered owing to next generation sequencing, but their biologic and pharmacological properties remain largely unknown. The molecular structure of the large protein complexes that the toxin forms with accessory proteins, which are included in some BoNT type A1 and B1 pharmacological preparations, have been determined. By far the largest effort has been dedicated to the testing and validation of BoNTs as therapeutic agents in an ever increasing number of applications, including pain therapy. BoNT type A1 has been also exploited in a variety of cosmetic treatments, alone or in combination with other agents, and this specific market has reached the size of the one dedicated to the treatment of medical syndromes. The pharmacological properties and mode of action of BoNTs have shed light on general principles of neuronal transport and protein-protein interactions and are stimulating basic science studies. Moreover, the wide array of BoNTs discovered and to be discovered and the production of recombinant BoNTs endowed with specific properties suggest novel uses in therapeutics with increasing disease/symptom specifity. These recent developments are reviewed here to provide an updated picture of the biologic mechanism of action of BoNTs, of their increasing use in pharmacology and in cosmetics, and of their toxicology. Copyright © 2017 by The Author(s).

Removal Capacities of Polycyclic Aromatic Hydrocarbons (PAHs by a Newly Isolated Strain from Oilfield Produced Water

Directory of Open Access Journals (Sweden)

Yi-Bin Qi

2017-02-01

Full Text Available The polycyclic aromatic hydrocarbon (PAH-degrading strain Q8 was isolated from oilfield produced water. According to the analysis of a biochemical test, 16S rRNA gene, house-keeping genes and DNA–DNA hybridization, strain Q8 was assigned to a novel species of the genus Gordonia. The strain could not only grow in mineral salt medium (MM and utilize naphthalene and pyrene as its sole carbon source, but also degraded mixed naphthalene, phenanthrene, anthracene and pyrene. The degradation ratio of these four PAHs reached 100%, 95.4%, 73.8% and 53.4% respectively after being degraded by Q8 for seven days. A comparative experiment found that the PAHs degradation efficiency of Q8 is higher than that of Gordonia alkaliphila and Gordonia paraffinivorans, which have the capacities to remove PAHs. Fourier transform infrared spectra, saturate, aromatic, resin and asphaltene (SARA and gas chromatography–mass spectrometry (GC–MS analysis of crude oil degraded by Q8 were also studied. The results showed that Q8 could utilize n-alkanes and PAHs in crude oil. The relative proportions of the naphthalene series, phenanthrene series, thiophene series, fluorene series, chrysene series, C21-triaromatic steroid, pyrene, and benz(apyrene were reduced after being degraded by Q8. Gordonia sp. nov. Q8 had the capacity to remediate water and soil environments contaminated by PAHs or crude oil, and provided a feasible way for the bioremediation of PAHs and oil pollution.

[Isolation of an excellent bio-flocculant-producing strain and its application in the treatment of cold-rolling waste oily water].

Science.gov (United States)

Lei, Guo-Yuan; Ding, Cui-Ping; Yang, Jia-Xuan

2011-09-01

An excellent strain (designated as T-3) which produces bio-flocculants was isolated from soil samples, and identified as Klebsiella sp. species based on the analysis of morphology, physiology and biochemistry and 16S rDNA sequences measurement. The effects of culture conditions such as pH values, temperature, carbon sources and nitrogen sources on bio-flocculants production by T-3 strain were studied. The experiment results show that T-3 strain has better adaptability to carbon sources and nitrogen sources, and higher capacity of bio-flocculants was obtained when the initial pH value of culture and temperature were 9 and 25 degrees C respectively. Based on the colorimetric reactions of proteins and polysaccharide substance, ultraviolet scanning analysis and Fourier Transform Infrared Spectroscopy analysis, it is found that the bio-flocculants produced by T-3 strain contains -OH and -COO(-) groups and belongs to anionic type flocculant. Moreover, the main component is polysaccharides. The treatment of oily cold-rolling wastewater by the bio-flocculant was investigated and the better result was obtained. When the dosages of CaCl2, bio-flocculants and poly aluminium chloride were 4 g x L(-1), 10% (volume fraction) and 1 g x L(-1) respectively, and the pH value was 7.0, the oil concentration, COD and turbidity were decreased to 10 mg x L(-1), 218.4 mg x L(-1) and 1.36 from 4 819 mg x L(-1), 28 456.8 mg x L(-1) and 3 950 with the removal efficiencies of 99.79%, 92.32% and 99.97% respectively. The interaction between flocculant and oily droplets is achieved by the interaction of Van der Waals force, hydrogen bond and the bridged coordination of Ca2+, in which the bridged coordination of Ca2+ is the dominant.

Production and evaluation of a recombinant chimeric vaccine against clostridium botulinum neurotoxin types C and D.

Directory of Open Access Journals (Sweden)

Luciana A F Gil

Full Text Available Bovine botulism is a fatal disease that is caused by botulinum neurotoxins (BoNTs produced by Clostridium botulinum serotypes C and D and that causes great economic losses, with nearly 100% lethality during outbreaks. It has also been considered a potential source of human food-borne illness in many countries. Vaccination has been reported to be the most effective way to control bovine botulism. However, the commercially available toxoid-based vaccines are difficult and hazardous to produce. Neutralizing antibodies targeted against the C-terminal fragment of the BoNT heavy chain (HC are known to confer efficient protection against lethal doses of BoNTs. In this study, a novel recombinant chimera, consisting of Escherichia coli heat-labile enterotoxin B subunit (LTB, a strong adjuvant of the humoral immune response, fused to the HC of BoNT serotypes C and D, was produced in E. coli. Mice vaccinated with the chimera containing LTB and an equivalent molar ratio of the chimera without LTB plus aluminum hydroxide (Al(OH3 developed 2 IU/mL of antitoxins for both serotypes. Guinea pigs immunized with the recombinant chimera with LTB plus Al(OH3 developed a protective immune response against both BoNT/C (5 IU/mL and BoNT/D (10 IU/mL, as determined by a mouse neutralization bioassay with pooled sera. The results achieved with guinea pig sera fulfilled the requirements of commercial vaccines for prevention of botulism, as determined by the Brazilian Ministry of Agriculture, Livestock and Food, Supply. The presence of LTB was essential for the development of a strong humoral immune response, as it acted in synergism with Al(OH3. Thus, the vaccine described in this study is a strong candidate for the control of botulism in cattle.

Direct fermentation of sweet sorghum juice by Clostridium acetobutylicum and Clostridium tetanomorphum to produce bio-butanol and organic acids

Directory of Open Access Journals (Sweden)

B. Ndaba

2015-06-01

Full Text Available Single- and co-culture clostridial fermentation was conducted to obtain organic alcohols and acids from sweet sorghum juice as a low cost feedstock. Different inoculum concentrations of single cultures (3, 5, 10 v/v % as well as different ratios of C. acetobutylicum to C. tetanomorphum (3:10, 10:3, 6.5:6.5, 3:3, and 10:10 v/v %, respectively were utilized for the fermentation. The maximum butanol concentration of 6.49 g/L was obtained after 96 h fermentation with 10 % v/v C. acetobutylicum as a single culture. The fermentation with 10% v/v C. tetanomorphum resulted in more than 5 g/l butyric acid production. Major organic acid concentration (lactic acid of 2.7 g/L was produced when an inoculum ratio of 6.5: 6.5 %v/v C. acetobutylicum to C. tetanomorphum was used.

A rapid enzymatic assay for high-throughput screening of adenosine-producing strains

Science.gov (United States)

Dong, Huina; Zu, Xin; Zheng, Ping; Zhang, Dawei

2015-01-01

Adenosine is a major local regulator of tissue function and industrially useful as precursor for the production of medicinal nucleoside substances. High-throughput screening of adenosine overproducers is important for industrial microorganism breeding. An enzymatic assay of adenosine was developed by combined adenosine deaminase (ADA) with indophenol method. The ADA catalyzes the cleavage of adenosine to inosine and NH3, the latter can be accurately determined by indophenol method. The assay system was optimized to deliver a good performance and could tolerate the addition of inorganic salts and many nutrition components to the assay mixtures. Adenosine could be accurately determined by this assay using 96-well microplates. Spike and recovery tests showed that this assay can accurately and reproducibly determine increases in adenosine in fermentation broth without any pretreatment to remove proteins and potentially interfering low-molecular-weight molecules. This assay was also applied to high-throughput screening for high adenosine-producing strains. The high selectivity and accuracy of the ADA assay provides rapid and high-throughput analysis of adenosine in large numbers of samples. PMID:25580842

Bacillus cereus panophthalmitis associated with intraocular gas bubble.

Science.gov (United States)

al-Hemidan, A; Byrne-Rhodes, K A; Tabbara, K F

1989-01-01

It has become increasingly apparent that Bacillus cereus can cause a severe and devastating form of endophthalmitis following penetrating trauma by a metallic object. B. cereus is an uncommon aetiological agent in non-clostridial gas-forming infections. The patient studied in this single case report showed evidence of intraocular gas mimicking gas gangrene infection. The physiology of non-clostridial bacteria producing gas from anaerobic metabolic conditions is reviewed. Further intraocular and systemic complications which may be avoided by accurate and early diagnosis and the use of recommended treatment with antibiotics such as clindamycin. Images PMID:2493262

Effect of ropy and capsular exopolysaccharides producing strain of ...

African Journals Online (AJOL)

The contribution of selected ropy and capsular Lactobacillus plantarum 162RM on texture of fermented milk as well as on the functionality of kareish cheese was established in this study. The cell suspension of this strain was used in combination with commercial starter cultures MY900 (Lactobacillus delbrueckii ssp.

Epitopic Profiling of Antibody Response against Neurotoxins from the Black Mamba (Dendroaspis polylepis)

DEFF Research Database (Denmark)

Jespersen, Martin Closter; Engmark, Mikael; Laustsen, Andreas Hougaard

The black mamba (Dendroaspis Polylepis) is among the most dangerous snakes in the world, with a venom dominated by three-finger toxins and dendrotoxins. Among the three-finger toxins, the α-neurotoxins (α-NT) are the most important, and these are conserved between snake species. Cross......-reactivity between threefinger toxins is known to occur, and understanding this phenomenon in depth may help guide future design of antivenoms to obtain optimal specificity against medically important toxins from different snake species. Using a bioinformatic approach, we investigated the cross-reactivity be- tween...

Bacteriocin-like inhibitory activities of seven Lactobacillus delbrueckii subsp. bulgaricus strains against antibiotic susceptible and resistant Helicobacter pylori strains.

Science.gov (United States)

Boyanova, L; Gergova, G; Markovska, R; Yordanov, D; Mitov, I

2017-12-01

The aim of the study was to detect anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains by four cell-free supernatant (CFS) types. Activity of non-neutralized and non-heat-treated (CFSs1), non-neutralized and heat-treated (CFSs2), pH neutralized, catalase-treated and non-heat-treated (CFSs3), or neutralized, catalase- and heat-treated (CFSs4) CFSs against 18 H. pylori strains (11 of which with antibiotic resistance) was evaluated. All GLB strains produced bacteriocin-like inhibitory substances (BLISs), the neutralized CFSs of two GLB strains inhibited >81% of test strains and those of four GLB strains were active against >71% of antibiotic resistant strains. Two H. pylori strains were BLIS resistant. The heating did not reduce the CFS activity. Briefly, all GLB strains evaluated produced heat-stable BLISs, although GLB and H. pylori strain susceptibility patterns exhibited differences. Bacteriocin-like inhibitory substance activity can be an advantage for the probiotic choice for H. pylori infection control. In this study, anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains was evaluated by four cell-free supernatant (CFS) types. The GLB strains produced heat-stable bacteriocin-like inhibitory substances (BLISs) with a strong anti-H. pylori activity and some neutralized, catalase- and heat-treated CFSs inhibited >83% of the test strains. Bacteriocin-like inhibitory substance production of GLB strains can render them valuable probiotics in the control of H. pylori infection. © 2017 The Society for Applied Microbiology.

A rapid bioassay for detecting saxitoxins using a Daphnia acute toxicity test

Energy Technology Data Exchange (ETDEWEB)

Ferrao-Filho, Aloysio da S., E-mail: aloysio@ioc.fiocruz.b [Laboratorio de Avaliacao e Promocao da Saude Ambiental, Departamento de Biologia, Instituto Oswaldo Cruz, FIOCRUZ, Av. Brasil 4365, Manguinhos, Rio de Janeiro, RJ 21045-900 (Brazil); Soares, Maria Carolina S., E-mail: mcarolsoares@gmail.co [Departamento de Engenharia Sanitaria e Ambiental Faculdade de Engenharia, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900 (Brazil); Freitas de Magalhaes, Valeria, E-mail: valeria@biof.ufrj.b [Laboratorio de Ecofisiologia e Toxicologia de Cianobacterias, Instituto de Biofisica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Rio de Janeiro, RJ 21949-900 (Brazil); Azevedo, Sandra M.F.O., E-mail: sazevedo@biof.ufrj.b [Laboratorio de Ecofisiologia e Toxicologia de Cianobacterias, Instituto de Biofisica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Rio de Janeiro, RJ 21949-900 (Brazil)

2010-06-15

Bioassays using Daphnia pulex and Moina micrura were designed to detect cyanobacterial neurotoxins in raw water samples. Phytoplankton and cyanotoxins from seston were analyzed during 15 months in a eutrophic reservoir. Effective time to immobilize 50% of the exposed individuals (ET{sub 50}) was adopted as the endpoint. Paralysis of swimming movements was observed between approx0.5-3 h of exposure to lake water containing toxic cyanobacteria, followed by an almost complete recovery of the swimming activity within 24 h after being placed in control water. The same effects were observed in bioassays with a saxitoxin-producer strain of Cylindrospermopsis raciborskii isolated from the reservoir. Regression analysis showed significant relationships between ET{sub 50}vs. cell density, biomass and saxitoxins content, suggesting that the paralysis of Daphnia in lake water samples was caused by saxitoxins found in C. raciborskii. Daphnia bioassay was found to be a sensitive method for detecting fast-acting neurotoxins in natural samples, with important advantages over mouse bioassays. - A new Daphnia bioassay, as an alternative to the mouse bioassay, is able to detect effects of fast-acting, potent neurotoxins in raw water.

A rapid bioassay for detecting saxitoxins using a Daphnia acute toxicity test

International Nuclear Information System (INIS)

Ferrao-Filho, Aloysio da S.; Soares, Maria Carolina S.; Freitas de Magalhaes, Valeria; Azevedo, Sandra M.F.O.

2010-01-01

Bioassays using Daphnia pulex and Moina micrura were designed to detect cyanobacterial neurotoxins in raw water samples. Phytoplankton and cyanotoxins from seston were analyzed during 15 months in a eutrophic reservoir. Effective time to immobilize 50% of the exposed individuals (ET 50 ) was adopted as the endpoint. Paralysis of swimming movements was observed between ∼0.5-3 h of exposure to lake water containing toxic cyanobacteria, followed by an almost complete recovery of the swimming activity within 24 h after being placed in control water. The same effects were observed in bioassays with a saxitoxin-producer strain of Cylindrospermopsis raciborskii isolated from the reservoir. Regression analysis showed significant relationships between ET 50 vs. cell density, biomass and saxitoxins content, suggesting that the paralysis of Daphnia in lake water samples was caused by saxitoxins found in C. raciborskii. Daphnia bioassay was found to be a sensitive method for detecting fast-acting neurotoxins in natural samples, with important advantages over mouse bioassays. - A new Daphnia bioassay, as an alternative to the mouse bioassay, is able to detect effects of fast-acting, potent neurotoxins in raw water.

Strain improvement in Streptomyces galilaeus, a producer of anthracycline antibiotics galirubins

International Nuclear Information System (INIS)

Kralovcova, E.; Blumauerova, M.; Vanek, Z.

1977-01-01

The production of epsilon-pyrromycinone glycosides in Streptomyces galilaeus increased 12-fold, with respect to the wild strain, as a result of a sequential procedure including both natural selection and treatment with mutagens (nitrous acid, UV light and γ irradiation). Nitrous acid exhibited the highest mutagenic effect, both in increasing the productivity and in inducing blocked mutants. A mutant strain blocked in the biosynthesis of glycosides and accumulating free epsilon-pyrromycinone as the principal metabolite was obtained. (author)

A Label Free Colorimetric Assay for the Detection of Active Botulinum Neurotoxin Type A by SNAP-25 Conjugated Colloidal Gold

Directory of Open Access Journals (Sweden)

Christopher Gwenin

2013-08-01

Full Text Available Botulinum neurotoxins are one of the most potent toxins known to man. Current methods of detection involve the quantification of the toxin but do not take into account the percentage of the toxin that is active. At present the assay used for monitoring the activity of the toxin is the mouse bioassay, which is lengthy and has ethical issues due to the use of live animals. This report demonstrates a novel assay that utilises the endopeptidase activity of the toxin to detect Botulinum neurotoxin in a pharmaceutical sample. The cleaving of SNAP-25 is monitored via UV-Visible spectroscopy with a limit of detection of 373 fg/mL and has been further developed into a high throughput method using a microplate reader detecting down to 600 fg/mL of active toxin. The results show clear differences between the toxin product and the placebo, which contains the pharmaceutical excipients human serum albumin and lactose, showing that the assay detects the active form of the toxin.

Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain

International Nuclear Information System (INIS)

Yang, Zhen; Kong, Fanxiang; Shi, Xiaoli; Yu, Yang; Zhang, Min

2015-01-01

Highlights: • UV-B radiation showed higher inhibition to non-toxin producing than toxin-producing strains on growth and photosynthetic activity. • Both intracellular and extracellular MC contents decreased markedly under UV-B radiation. • Higher resistance to UV-B radiation helped toxin-producing M. aeruginosa to predominate in the competition. - Abstract: Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms

Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhen, E-mail: zhyang@niglas.ac.cn; Kong, Fanxiang, E-mail: fxkong@niglas.ac.cn; Shi, Xiaoli; Yu, Yang; Zhang, Min

2015-02-11

Highlights: • UV-B radiation showed higher inhibition to non-toxin producing than toxin-producing strains on growth and photosynthetic activity. • Both intracellular and extracellular MC contents decreased markedly under UV-B radiation. • Higher resistance to UV-B radiation helped toxin-producing M. aeruginosa to predominate in the competition. - Abstract: Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms.

Molecular characterisation of human Shiga toxin-producing Escherichia coli O26 strains: results of an outbreak investigation, Romania, February to August 2016.

Science.gov (United States)

Usein, Codruţa-Romaniţa; Ciontea, Adriana Simona; Militaru, Cornelia Mãdãlina; Condei, Maria; Dinu, Sorin; Oprea, Mihaela; Cristea, Daniela; Michelacci, Valeria; Scavia, Gaia; Zota, Lavinia Cipriana; Zaharia, Alina; Morabito, Stefano

2017-11-01

IntroductionAt the beginning of 2016, an increase in paediatric haemolytic uremic syndrome (HUS) cases was observed in Romania. The microbiological investigations allowed isolation of Shiga toxin-producing Escherichia coli (STEC) O26 as the causative agent from most cases. Methods: An enhanced national surveillance of HUS and severe diarrhoea was established across the country following the identification of the first cases and was carried out until August 2016. A total of 15 strains were isolated from 10 HUS and five diarrhoea cases. Strains were characterised by virulence markers (i.e. stx type/subtype, eae , ehxA genes), phylogroup, genetic relatedness and clonality using PCR-based assays, PFGE and multilocus sequence typing (MLST). The first six strains were further characterised by whole genome sequencing (WGS). Results: Five PCR-defined genotypes were distinguished. All strains from HUS cases harboured stx2a and eae , with or without stx1a , while strains from diarrhoea cases carried exclusively stx1a and eae genes. PFGE resolved strains into multiple pulsotypes, compatible with a certain geographic segregation of the cases, and strains were assigned to phylogroup B1 and sequence type (ST) 21. WGS confirmed the results of conventional molecular methods, brought evidence of O26:H11 serotype, and complemented the virulence profiles. Discussion/conclusion: This first description of STEC O26 strains from cases in Romania showed that the isolates belonged to a diverse population. The virulence content of most strains highlighted a high risk for severe outcome in infected patients. Improving the national surveillance strategy for STEC infections in Romania needs to be further considered.

No evidence of the Shiga toxin-producing E. coli O104:H4 outbreak strain or enteroaggregative E. coli (EAEC found in cattle faeces in northern Germany, the hotspot of the 2011 HUS outbreak area

Directory of Open Access Journals (Sweden)

Wieler Lothar H

2011-11-01

Full Text Available Abstract Background Ruminants, in particular bovines, are the primary reservoir of Shiga toxin-producing E. coli (STEC, but whole genome analyses of the current German ESBL-producing O104:H4 outbreak strain of sequence type (ST 678 showed this strain to be highly similar to enteroaggregative E. coli (EAEC. Strains of the EAEC pathotype are basically adapted to the human host. To clarify whether in contrast to this paradigm, the O104:H4 outbreak strain and/or EAEC may also be able to colonize ruminants, we screened a total of 2.000 colonies from faecal samples of 100 cattle from 34 different farms - all located in the HUS outbreak region of Northern Germany - for genes associated with the O104:H4 HUS outbreak strain (stx2, terD, rfbO104, fliCH4, STEC (stx1, stx2, escV, EAEC (pAA, aggR, astA, and ESBL-production (blaCTX-M, blaTEM, blaSHV. Results The faecal samples contained neither the HUS outbreak strain nor any EAEC. As the current outbreak strain belongs to ST678 and displays an en-teroaggregative and ESBL-producing phenotype, we additionally screened selected strains for ST678 as well as the aggregative adhesion pattern in HEp-2 cells. However, we were unable to find any strains belonging to ST678 or showing an aggregative adhesion pattern. A high percentage of animals (28% shed STEC, corroborating previous knowl-edge and thereby proving the validity of our study. One of the STEC also harboured the LEE pathogenicity island. In addition, eleven animals shed ESBL-producing E. coli. Conclusions While we are aware of the limitations of our survey, our data support the theory, that, in contrast to other Shiga-toxin producing E. coli, cattle are not the reservoir for the O104:H4 outbreak strain or other EAEC, but that the outbreak strain seems to be adapted to humans or might have yet another reservoir, raising new questions about the epidemiology of STEC O104:H4.

Antiviral activity of the exopolysaccharide produced by Serratia sp. strain Gsm01 against Cucumber mosaic virus.

Science.gov (United States)

Ipper, Nagesh S; Cho, Saeyoull; Lee, Seon Hwa; Cho, Jun Mo; Hur, Jang Hyun; Lim, Chun Keun

2008-01-01

The potential of the exopolysaccharide (EPS) from a Serratia sp. strain Gsm01 as an antiviral agent against a yellow strain of Cucumber mosaic virus (CMV-Y) was evaluated in tobacco plants (Nicotiana tabacum cv. Xanthi-nc). The spray treatment of plants using an EPS preparation, 72 before CMV-Y inoculation, protected them against symptom appearance. Fifteen days after challenge inoculation with CMVY, 33.33% of plants showed mosaic symptoms in EPS-treated plants compared with 100% in the control plants. The EPS-treated plants, which showed mosaic symptoms, appeared three days later than the controls. The enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) analyses of the leaves of the protected plants revealed that the EPS treatment affected virus accumulation in those plants. Analysis of phenylalanine ammonia lyase, peroxidase, and phenols in protected plants revealed enhanced accumulation of these substances. The pathogenesis-related (PR) genes expression represented by PR-1b was increased in EPS-treated plants. This is the first report of a systemic induction of protection triggered by EPS produced by Serratia sp. against CMV-Y.

Biosurfactant-producing yeasts widely inhabit various vegetables and fruits.

Science.gov (United States)

Konishi, Masaaki; Maruoka, Naruyuki; Furuta, Yoshifumi; Morita, Tomotake; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

2014-01-01

The isolation of biosurfactant-producing yeasts from food materials was accomplished. By a combination of a new drop collapse method and thin-layer chromatography, 48 strains were selected as glycolipid biosurfactant producers from 347 strains, which were randomly isolated from various vegetables and fruits. Of the producers, 69% were obtained from vegetables of the Brassica family. Of the 48 producers, 15 strains gave relatively high yields of mannosylerythritol lipids (MELs), and were identified as Pseudozyma yeasts. These strains produced MELs from olive oil at yields ranging from 8.5 to 24.3 g/L. The best yield coefficient reached 0.49 g/g as to the carbon sources added. Accordingly, MEL producers were isolated at high efficiency from various vegetables and fruits, indicating that biosurfactant producers are widely present in foods. The present results should facilitate their application in the food and related industries.

Effects of atomoxetine on attention in Wistar rats treated with the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4)

NARCIS (Netherlands)

Hauser, J.; Reissmann, A.; Sontag, T.A.; Tucha, Oliver; Lange, K.W.

2017-01-01

The aim of the present study was to assess the effects of the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4), which allows a depletion of noradrenergic terminals in a dose-dependent manner, on attention in rats as measured using the five-choice serial-reaction time task (5CSRTT). In

Strain of Fusarium oxysporum Isolated From Almond Hulls Produces Styrene and 7-Methyl-1,3,5-Cyclooctatriene as the Principal Volatile Components

Science.gov (United States)

An isolated strain of Fusarium oxysporum from the hulls of Prunus dulcis (sweet almond) was found to produce relatively large quantities of the hydrocarbons styrene and three isomers of 7-methyl-1,3,5-cyclooctatriene (MCOT). Production of styrene and MCOT was reproduced on small scale using potato d...

[EFFICIENCY OF INTRODUCING CAROTENE PRODUCING STRAINS BACILLUS SP. 1.1 AND B. AMYLOLIQUEFACIENS UCM B-5113 INTO THE CHIKENS DIET].

Science.gov (United States)

Nechypurenko, O O; Kharhota M A; Avdeeva, L V

2015-01-01

It was shown the efficiency of carotene producing strains Bacillus sp. 1.1 and B. amyloliquefaciens UCM B-5113 in the diet of chickens. Also it was detected the lowering of the quantitative content of bacterial genera Enterococcus, Staphylococcus, family Enterobacteriaceae in the gut after eating by chickens cross "H&N Brown Nick" fodder with strains Bacillus sp. 1.1 and B. amyloliquefaciens UCM B-5113 alone and in composition in quantities 1 x 10(10) CFU per 1 g of feed. On the 18th day after introduction of cultures Bacillus sp. 1.1, B. amyloliquefaciens UCM B-5113 and their composition in the diet of poultry we revealed the increasing of body weight by 21.6, 7.6 and 22.0%, respectively, comparesing to controls. Also due to Bacillus sp. 1.1 it was detected the restore of intestinal villous structures, tissues of spleen, liver and heart. We found the additive effect of the composition of the investigated strains of bacteria genus Bacillus to the chickens.

A Monoclonal Antibody Based Capture ELISA for Botulinum Neurotoxin Serotype B: Toxin Detection in Food

Directory of Open Access Journals (Sweden)

Larry H. Stanker

2013-11-01

Full Text Available Botulism is a serious foodborne neuroparalytic disease, caused by botulinum neurotoxin (BoNT, produced by the anaerobic bacterium Clostridium botulinum. Seven toxin serotypes (A–H have been described. The majority of human cases of botulism are caused by serotypes A and B followed by E and F. We report here a group of serotype B specific monoclonal antibodies (mAbs capable of binding toxin under physiological conditions. Thus, they serve as capture antibodies for a sandwich (capture ELISA. The antibodies were generated using recombinant peptide fragments corresponding to the receptor-binding domain of the toxin heavy chain as immunogen. Their binding properties suggest that they bind a complex epitope with dissociation constants (KD’s for individual antibodies ranging from 10 to 48 × 10−11 M. Assay performance for all possible combinations of capture-detector antibody pairs was evaluated and the antibody pair resulting in the lowest level of detection (L.O.D., ~20 pg/mL was determined. Toxin was detected in spiked dairy samples with good recoveries at concentrations as low as 0.5 pg/mL and in ground beef samples at levels as low as 2 ng/g. Thus, the sandwich ELISA described here uses mAb for both the capture and detector antibodies (binding different epitopes on the toxin molecule and readily detects toxin in those food samples tested.

A monoclonal antibody based capture ELISA for botulinum neurotoxin serotype B: toxin detection in food.

Science.gov (United States)

Stanker, Larry H; Scotcher, Miles C; Cheng, Luisa; Ching, Kathryn; McGarvey, Jeffery; Hodge, David; Hnasko, Robert

2013-11-18

Botulism is a serious foodborne neuroparalytic disease, caused by botulinum neurotoxin (BoNT), produced by the anaerobic bacterium Clostridium botulinum. Seven toxin serotypes (A-H) have been described. The majority of human cases of botulism are caused by serotypes A and B followed by E and F. We report here a group of serotype B specific monoclonal antibodies (mAbs) capable of binding toxin under physiological conditions. Thus, they serve as capture antibodies for a sandwich (capture) ELISA. The antibodies were generated using recombinant peptide fragments corresponding to the receptor-binding domain of the toxin heavy chain as immunogen. Their binding properties suggest that they bind a complex epitope with dissociation constants (KD's) for individual antibodies ranging from 10 to 48 × 10-11 M. Assay performance for all possible combinations of capture-detector antibody pairs was evaluated and the antibody pair resulting in the lowest level of detection (L.O.D.), ~20 pg/mL was determined. Toxin was detected in spiked dairy samples with good recoveries at concentrations as low as 0.5 pg/mL and in ground beef samples at levels as low as 2 ng/g. Thus, the sandwich ELISA described here uses mAb for both the capture and detector antibodies (binding different epitopes on the toxin molecule) and readily detects toxin in those food samples tested.

Photoresponsive nanocapsulation of cobra neurotoxin and enhancement of its central analgesic effects under red light

Directory of Open Access Journals (Sweden)

Yang Q

2017-05-01

Full Text Available Qian Yang, Chuang Zhao, Jun Zhao, Yong Ye Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, People’s Republic of China Abstract: Cobra neurotoxin (CNT, a peptide isolated from snake venom of Naja naja atra, shows central analgesic effects in our previous research. In order to help CNT pass through blood–brain barrier (BBB and improve its central analgesic effects, a new kind of CNT nanocapsules were prepared by double emulsification with soybean lecithin and cholesterol as the shell, and pheophorbide as the photosensitizer added to make it photoresponsive. The analgesic effects were evaluated by hot plate test and acetic acid-induced writhing in mice. The CNT nanocapsules had an average particle size of 229.55 nm, zeta potential of -53.00 mV, encapsulation efficiency of 84.81% and drug loading of 2.98%, when the pheophorbide content was 1% of lecithin weight. Pheophorbide was mainly distributed in outer layer of the CNT nanocapsules and increased the release of the CNT nanocapsules after 650 nm illumination. The central analgesic effects were improved after intraperitoneal injection of CNT at 25 and 50 µg·kg-1 under 650 nm irradiation for 30 min in the nasal cavity. Activation of pheophorbide by red light generated reactive oxygen species which opened the nanocapsules and BBB and helped the CNT enter the brain. This research provides a new drug delivery for treatment of central pain. Keywords: cobra neurotoxin, nanocapsules, photoresponsive, central analgesic effects, red light, drug delivery, photosensitizer

Comparison of the catalytic properties of the botulinum neurotoxin subtypes A1 and A5.

Science.gov (United States)

Wang, Dongxia; Krilich, Joan; Pellett, Sabine; Baudys, Jakub; Tepp, William H; Barr, John R; Johnson, Eric A; Kalb, Suzanne R

2013-12-01

Clostridium botulinum neurotoxins (BoNTs) cause the life-threatening disease botulism through the inhibition of neurotransmitter release by cleaving essential SNARE proteins. There are seven serologically distinctive types of BoNTs and many subtypes within a serotype have been identified. BoNT/A5 is a recently discovered subtype of type A botulinum neurotoxin which possesses a very high degree of sequence similarity and identity to the well-studied A1 subtype. In the present study, we examined the endopeptidase activity of these two BoNT/A subtypes and our results revealed significant differences in substrate binding and cleavage efficiency between subtype A5 and A1. Distinctive hydrolysis efficiency was observed between the two toxins during cleavage of the native substrate SNAP-25 versus a shortened peptide mimic. N-terminal truncation studies demonstrated that a key region of the SNAP-25, including the amino acid residues at 151 through 154 located in the remote binding region of the substrate, contributed to the differential catalytic properties between A1 and A5. Elevated binding affinity of the peptide substrate resulted from including these important residues and enhanced BoNT/A5's hydrolysis efficiency. In addition, mutations of these amino acid residues affect the proteolytic performance of the two toxins in different ways. This study provides a better understanding of the biological activity of these toxins, their performance characteristics in the Endopep-MS assay to detect BoNT in clinical samples and foods, and is useful for the development of peptide substrates. © 2013. Published by Elsevier B.V. All rights reserved.

Bacteriocin-producing Enterococci from Rabbit Meat

Directory of Open Access Journals (Sweden)

Szabóová, R.

2012-01-01

Full Text Available Aims: Enterococci are lactic acid bacteria belonging to the division Firmicutes. They occur in different ecosystems, rabbits including. Enterococci can possess probiotic properties and produce antimicrobial substances-bacteriocins. Rabbit meat as nutritionally healthy food offers novel source to study bacteriocin-producing and/or probiotic enterococci. Methodology and results: Enterococci were detected from rabbit meat samples (42. Most of the isolates were allotted to the species Enterococcus faecium by PCR method. The isolates have possessed the structural genes for enterocins A, P, B production. The inhibitory substances produced by the isolated enterococci inhibited the growth of 12 indicators. Of 34 isolates, 15 strains have shown the antimicrobial activity against L. monocytogenes CCM 4699, 12 strains against S. aureus 3A3, 10 strains against S. aureus 5A2 as well as Salmonella enterica serovar Enteritidis PT4. Moreover, enterococci have tolerated 5 % bile, low pH; they have produced lactid acid in the amount from 0.740 ± 0.091 to 1.720 ± 0.095 mmol/l. The isolates were mostly sensitive to antibiotics. Conclusion, significance and impact of study: Bacteriocin-producing strain E. faecium M3a has been selected for more detail characterization of its bacteriocin and probiotic properties with the aim for its further application as an additive.

The importance of Bordetella pertussis strains which do not produce virulence factors in the epidemiology of pertussis

Directory of Open Access Journals (Sweden)

Maciej Polak

2017-05-01

Full Text Available Bordetella pertussis strains, which have lost the ability to produce antigens, such as pertactin - Prn, pertussis toxin - Ptx, filamentous haemagglutinin - FHA, fimbriae type 2 and 3 - Fim 2 and 3, tracheal colonization factor - TcfA, have recently been isolated in countries with a high vaccination coverage. The emergence of such isolates might have resulted from B. pertussis natural evolution course or adaptive mechanisms, allowing increased circulation of the pathogen in vaccinated populations. So far, the majority of described mutants were deficient in the Prn production. Prn deficient isolates were found in countries which use acellular pertussis vaccines (aP in routine immunization programmes. The increase of frequency of Prn¯ strains isolation was correlated with the period of routine vaccination with aP vaccines. In most countries, the spread of these isolates has resulted from independent mutations rather than from the expansion of a single clone. Prn¯ isolates were collected from patients showing typical clinical symptoms of pertussis found for Prn+ strains. Results of in vitro and in vivo studies have shown that Prn¯, Ptx¯ and FHA¯ isolates retain cytotoxic properties, and besides Ptx¯ isolates, were lethal in intranasally infected mice. Further explanation of the impact of antigen deficiencies on virulence and transmission of B. pertussis in the context of the continuous increase of pertussis incidence is necessary to develop a new, optimized strategy of pertussis prevention.

Strain comparisons in aquaculture species: a manual

OpenAIRE

Ponzoni, R.W.; James, J.W.; Nguyen, N.H.; Mekkawy, W.; Khaw, H.L.

2013-01-01

When different strains or breeds of a particular species are available, the best choice is seldom immediately obvious for producers. Scientists are also interested in the relative performance of different strains because it provides a basis for recommendations to producers and it often stimulates the conduct of work aimed at unraveling the underlying biological mechanisms involved in the expression of such differences. Hence, strain or breed comparisons of some sort are frequently conducted. ...

Exopolysaccharide-producing Bifidobacterium animalis subsp. lactis strains and their polymers elicit different responses on immune cells from blood and gut associated lymphoid tissue.

Science.gov (United States)

Hidalgo-Cantabrana, Claudio; Nikolic, Milica; López, Patricia; Suárez, Ana; Miljkovic, Marija; Kojic, Milan; Margolles, Abelardo; Golic, Natasa; Ruas-Madiedo, Patricia

2014-04-01

The effect of exopolysaccharide (EPS) producing bifidobacteria, and the EPS derived thereof, on the modulation of immune response was evaluated. Cells isolated from gut associated lymphoid tissue (GALT) and from peripheral blood mononuclear cells (PBMC) of naïve rats were used. The proliferation and cytokine production of these immune cells in the presence of the three isogenic Bifidobacterium animalis subsp. lactis strains (A1, A1dOx and A1dOxR), as well as their purified polymers, were in vitro analysed. The cytokine pattern produced by immune cells isolated from GALT showed that most levels remained stable in the presence of the three strains or their corresponding polymers. However, in PBMC the UV-inactivated bacteria induced higher levels of the ratios IFNγ/IL-17, TNFα/IL-10 and TNFα/TGFβ, and no variation in the ratio IFNγ/IL-4. Thus, B. animalis subsp. lactis strains were able to activate blood monocytes as well as T lymphocytes towards a mild inflammatory Th1 response. Furthermore, only the EPS-A1dOxR was able to stimulate a response in a similar way than its EPS-producing bacterium. Our work supports the notion that some bifidobacterial EPS could play a role in mediating the dialog of these microorganisms with the immune system. In addition, this study emphasizes the effect that the origin of the immune cells has in results obtained; this could explain the great amount of contradiction found in literature about the immunomodulation capability of EPS from probiotic bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biopesticide activity of sugarcane associated rhizobacteria: Ochrobactrum intermedium strain NH-5 and Stenotrophomonas maltophilia strain NH-300 against red rot under field conditions

Directory of Open Access Journals (Sweden)

Muhammad Nadeem HASSAN

2014-09-01

Full Text Available Colletotrichum falcatum is the major fungal pathogen causing sugarcane red rot. Four antagonistic bacterial strains exhibiting biocontrol activity against this pathogen in greenhouse conditions were characterized for production of different antifungal metabolites and biocontrol determinants to elucidate the mechanism of action involved in their antagonistic activity. The strains were also evaluated under field conditions to assess their biocontrol potential. All the strains produced hydrogen cyanide (HCN, and volatile and diffusible antibiotics. In addition, the Ochrobactrum intermedium strain NH-5 produced siderophores and the broad spectrum antibiotic 2, 4-diacetylphloroglucinol (2,4-DAPG; Pseudomonas sp. NH-203 produced siderophores, and Pseudomonas sp. NH-276 produced protease. Two strains, Ochrobactrum intermedium NH-5 and Stenotrophomonas maltophilia NH-300, exhibited good biocontrol activity, suppressing red rot by 44–52% on two sugarcane varieties, SPF-234 and Co-1148, in field experiments. The strains gave consistent results in three consecutive years and showed potential to be used as biopesticides.

Challenges in searching for therapeutics against Botulinum Neurotoxins.

Science.gov (United States)

Pirazzini, Marco; Rossetto, Ornella

2017-05-01

Botulinum neurotoxins (BoNTs) are the most potent toxins known. BoNTs are responsible for botulism, a deadly neuroparalytic syndrome caused by the inactivation of neurotransmitter release at peripheral nerve terminals. Thanks to their specificity and potency, BoNTs are both considered potential bio-weapons and therapeutics of choice for a variety of medical syndromes. Several variants of BoNTs have been identified with individual biological properties and little antigenic relation. This expands greatly the potential of BoNTs as therapeutics but poses a major safety problem, increasing the need for finding appropriate antidotes. Areas covered: The authors describe the multi-step molecular mechanism through which BoNTs enter nerve terminals and discuss the many levels at which the toxins can be inhibited. They review the outcomes of the different strategies adopted to limit neurotoxicity and counter intoxication. Potential new targets arising from the last discoveries of the mechanism of action and the approaches to promote neuromuscular junction recovery are also discussed. Expert opinion: Current drug discovery efforts have mainly focused on BoNT type A and addressed primarily light chain proteolytic activity. Development of pan-BoNT inhibitors acting independently of BoNT immunological properties and targeting a common step of the intoxication process should be encouraged.

Accelerated Intoxication of GABAergic Synapses by Botulinum Neurotoxin A Disinhibits Stem Cell-Derived Neuron Networks Prior to Network Silencing

Science.gov (United States)

2015-04-23

administered BoNT can lead to central nervous system intoxication is currently being debated. Recent findings in vitro and in vivo suggest that BoNT...Literature 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Accelerated intoxication of GABAergic synapses by botulinum neurotoxin A disinhibits 5a...April 2015 Published: 23 April 2015 Citation: Beske PH, Scheeler SM, AdlerM and McNutt PM (2015) Accelerated intoxication of GABAergic synapses by

NEW STRAIN PRODUCERS OF BIOBUTANOL. III. METHODS OF INCREASED BUTANOL ACCUMULATION FROM BIOMASS OF SWITCHGRASS Panicum virgatum L.

Directory of Open Access Journals (Sweden)

Tigunova O. O.

2015-08-01

Full Text Available The aim of this work was to enlarge accumulation of butanol from switchgrass Panicum virgatum L. biomass using strains-producers obtained from grounds and silts of Kyiv lakes. The objects of the study were strains of C. acetobutylicum ІМВ B-7407 (IFBG C6H, Clostridium acetobutylicum IFBG C6H 5М and Clostridium tyrobutyricum IFBG C4B from the "Collections of microbial strains and lines of plants for food and agricultural biotechnology" of the Public Institution "Institute of Food Biotechnology and Genomics" of the National Academy of Sciences of Ukraine. Gas chromatography was used to determine the alcohol concentration at the stage of solvent synthesis. To determine the effect of butanol precursors during cultivation, butyric, lactic and acetic acids were used. Optimization of processing parameters, which was based on the needs of cultures, allowed us to increase the yield by 20 and 50% for the initial and mutant strain respectively. Using synthetic precursors (such as lactic, butyric and acetic acid during cultivation increased total concentration of butanol by 1.7 times. To optimize the process, a study was carried out using acetone- butyl grains. Using of acetone-butyl grains in concentrations up to 60% does not affect the synthesis of butanol by C. acetobutylicum IFBG C6H 5M. Increasing the concentration of grains led to decrease in accumulation of butanol. Almost double increase in accumulation of the target product (butanol was achieved using two-stage fermentation and/or precursors of synthesis. It was shown the possibility of using acetone-butyl grains in fermentation. As a result the mass fraction of the waste was reduced.

Clostridium botulinum serotype D neurotoxin and toxin complex bind to bovine aortic endothelial cells via sialic acid.

Science.gov (United States)

Yoneyama, Tohru; Miyata, Keita; Chikai, Tomoyuki; Mikami, Akifumi; Suzuki, Tomonori; Hasegawa, Kimiko; Ikeda, Toshihiko; Watanabe, Toshihiro; Ohyama, Tohru; Niwa, Koichi

2008-12-01

Botulinum neurotoxin (BoNT) is produced as a large toxin complex (L-TC) associated with nontoxic nonhemagglutinin (NTNHA) and three hemagglutinin subcomponents (HA-70, -33 and -17). The binding properties of BoNT to neurons and L-TC to intestinal epithelial cells are well documented, while those to other tissues are largely unknown. Here, to obtain novel insights into the pathogenesis of foodborne botulism, we examine whether botulinum toxins bind to vascular endothelial cells. BoNT and 750 kDa L-TC (a complex of BoNT, NTNHA and HAs) of Clostridium botulinum serotype D were incubated with bovine aortic endothelial cells (BAECs), and binding to the cells was assessed using sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot. Both BoNT and L-TC bound to BAECs, with L-TC showing stronger binding. Binding of BoNT and L-TC to BAECs was significantly inhibited by N-acetyl neuraminic acid in the cell culture medium or by treatment of the cells with neuraminidase. However, galactose, lactose or N-acetyl galactosamine did not significantly inhibit toxin binding to the cells. This is the first report demonstrating that BoNT and L-TC bind to BAECs via sialic acid, and this mechanism may be important in the trafficking pathway of BoNT in foodborne botulism.

Characterization and properties of biosurfactants produced by a newly isolated strain Bacillus methylotrophicus DCS1 and their applications in enhancing solubility of hydrocarbon.

Science.gov (United States)

Jemil, Nawel; Ben Ayed, Hanen; Hmidet, Noomen; Nasri, Moncef

2016-11-01

Six biosurfactant-producing bacteria were isolated from hydrocarbon contaminated soils in Sfax, Tunisia. Isolates were screened for biosurfactant production by different conventional methods including hemolytic activity, surface tension reduction, drop-collapsing and oil displacement tests. All these screening tests show that all the isolates behave differently. Among the isolated bacteria, DCS1 strain was selected for further studies based on its highest activities and it was identified as Bacillus methylotrophicus DCS1. This strain was found to be a potent producer of biosurfactant when cultivated in mineral-salts medium supplemented with diesel oil (2 %, v/v) as a sole carbon source. Physicochemical properties and stability of biosurfactants synthesized by B. methylotrophicus DCS1 were investigated. The produced biosurfactants DCS1, from Landy medium, possess high surface activity that could lower the surface tension of water to a value of 31 from 72 mN m(-1) and have a critical micelle concentration (CMC) of 100 mg L(-1). Compared with SDS and Tween 80, biosurfactants showed excellent emulsification activities against different hydrocarbon substrates and high solubilization efficiency towards diesel oil. Biosurfactants DCS1 showed good stability in a wide range of temperature, pH and salinity. These results suggested that biosurfactants produced by B. methylotrophicus DCS1 could be an alternative to chemically synthesized surfactants for use in bioremediation processes to enhance the solubility of hydrophobic compounds.

Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

Science.gov (United States)

Andersen, Mikael R.; Salazar, Margarita P.; Schaap, Peter J.; van de Vondervoort, Peter J.I.; Culley, David; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristian F.; Albang, Richard; Albermann, Kaj; Berka, Randy M.; Braus, Gerhard H.; Braus-Stromeyer, Susanna A.; Corrochano, Luis M.; Dai, Ziyu; van Dijck, Piet W.M.; Hofmann, Gerald; Lasure, Linda L.; Magnuson, Jon K.; Menke, Hildegard; Meijer, Martin; Meijer, Susan L.; Nielsen, Jakob B.; Nielsen, Michael L.; van Ooyen, Albert J.J.; Pel, Herman J.; Poulsen, Lars; Samson, Rob A.; Stam, Hein; Tsang, Adrian; van den Brink, Johannes M.; Atkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Grigoriev, Igor V.; Kubicek, Christian P.; Martinez, Diego; van Peij, Noël N.M.E.; Roubos, Johannes A.; Nielsen, Jens; Baker, Scott E.

2011-01-01

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi. PMID:21543515

Intracellular synthesis of glutamic acid in Bacillus methylotrophicus SK19.001, a glutamate-independent poly(γ-glutamic acid)-producing strain.

Science.gov (United States)

Peng, Yingyun; Zhang, Tao; Mu, Wanmeng; Miao, Ming; Jiang, Bo

2016-01-15

Bacillus methylotrophicus SK19.001 is a glutamate-independent strain that produces poly(γ-glutamic acid) (γ-PGA), a polymer of D- and L-glutamic acids that possesses applications in food, the environment, agriculture, etc. This study was undertaken to explore the synthetic pathway of intracellular L- and D-glutamic acid in SK19.001 by investigating the effects of tricarboxylic acid cycle intermediates and different amino acids as metabolic precursors on the production of γ-PGA and analyzing the activities of the enzymes involved in the synthesis of L- and D-glutamate. Tricarboxylic acid cycle intermediates and amino acids could participate in the synthesis of γ-PGA via independent pathways in SK19.001. L-Aspartate aminotransferase, L-glutaminase and L-glutamate synthase were the enzymatic sources of L-glutamate. Glutamate racemase was responsible for the formation of D-glutamate for the synthesis of γ-PGA, and the synthetase had stereoselectivity for glutamate substrate. The enzymatic sources of L-glutamate were investigated for the first time in the glutamate-independent γ-PGA-producing strain, and multiple enzymatic sources of L-glutamate were verified in SK19.001, which will benefit efforts to improve production of γ-PGA with metabolic engineering strategies. © 2015 Society of Chemical Industry.

Isolation and molecular characterization of phytase producing ...

African Journals Online (AJOL)

Isolation and molecular characterization of phytase producing bacteria from Malaysia hot springs. ... The strains were further analyzed in broth culture using sodium phytate as substrate. Among them, strain L3 was selected as the best producer (0.16 U/ml after 72 h of culture). This phytase showed optimal activity at 37 °C ...

Complete genome sequence of N2-fixing model strain Klebsiella sp. nov. M5al, which produces plant cell wall-degrading enzymes and siderophores

Directory of Open Access Journals (Sweden)

Zhili Yu

2018-03-01

Full Text Available The bacterial strain M5al is a model strain for studying the molecular genetics of N2-fixation and molecular engineering of microbial production of platform chemicals 1,3-propanediol and 2,3-butanediol. Here, we present the complete genome sequence of the strain M5al, which belongs to a novel species closely related to Klebsiella michiganensis. M5al secretes plant cell wall-degrading enzymes and colonizes rice roots but does not cause soft rot disease. M5al also produces siderophores and contains the gene clusters for synthesis and transport of yersiniabactin which is a critical virulence factor for Klebsiella pathogens in causing human disease. We propose that the model strain M5al can be genetically modified to study bacterial N2-fixation in association with non-legume plants and production of 1,3-propanediol and 2,3-butanediol through degradation of plant cell wall biomass.

Evidence for paralytic shellfish poisons in the freshwater cyanobacterium Lyngbya wollei (Farlow ex Gomont) comb. nov.

Science.gov (United States)

Carmichael, W W; Evans, W R; Yin, Q Q; Bell, P; Moczydlowski, E

1997-08-01

Lyngbya wollei (Farlow ex Gomont) comb. nov., a perennial mat-forming filamentous cyanobacterium prevalent in lakes and reservoirs of the southeastern United States, was found to produce a potent, acutely lethal neurotoxin when tested in the mouse bioassay. Signs of poisoning were similar to those of paralytic shellfish poisoning. As part of the Tennessee Valley Authority master plan for Guntersville Reservoir, the mat-forming filamentous cyanobacterium L. wollei, a species that had recently invaded from other areas of the southern United States, was studied to determine if it could produce any of the known cyanotoxins. Of the 91 field samples collected at 10 locations at Guntersville Reservoir, Ala., on the Tennessee River, over a 3-year period, 72.5% were toxic. The minimum 100% lethal doses of the toxic samples ranged from 150 to 1,500 mg kg of lyophilized L. wollei cells-1, with the majority of samples being toxic at 500 mg kg-1. Samples bioassayed for paralytic shellfish toxins by the Association of Official Analytical Chemists method exhibited saxitoxin equivalents ranging from 0 to 58 micrograms g (dry weight)-1. Characteristics of the neurotoxic compound(s), such as the lack of adsorption by C18 solid-phase extraction columns, the short retention times on C18 high-performance liquid chromatography (HPLC) columns, the interaction of the neurotoxins with saxiphilin (a soluble saxitoxin-binding protein), and external blockage of voltage-sensitive sodium channels, led to our discovery that this neurotoxin(s) is related to the saxitoxins, the compounds responsible for paralytic shellfish poisonings. The major saxitoxin compounds thus far identified by comparison of HPLC fluorescence retention times are decarbamoyl gonyautoxins 2 and 3. There was no evidence of paralytic shellfish poison C toxins being produced by L. wollei. Fifty field samples were placed in unialgal culture and grown under defined culture conditions. Toxicity and signs of poisoning for these

Technological characterization and survival of the exopolysaccharide-producing strain Lactobacillus delbrueckii subsp. lactis 193 and its bile-resistant derivative 193+ in simulated gastric and intestinal juices.

Science.gov (United States)

Burns, Patricia; Vinderola, Gabriel; Reinheimer, Jorge; Cuesta, Isabel; de Los Reyes-Gavilán, Clara G; Ruas-Madiedo, Patricia

2011-08-01

The capacity of lactic acid bacteria to produce exopolysaccharides (EPS) conferring microorganisms a ropy phenotype could be an interesting feature from a technological point of view. Progressive adaptation to bile salts might render some lactobacilli able to overcome physiological gut barriers but could also modify functional properties of the strain, including the production of EPS. In this work some technological properties and the survival ability in simulated gastrointestinal conditions of Lactobacillus delbrueckii subsp. lactis 193, and Lb. delbrueckii subsp. lactis 193+, a strain with stable bile-resistant phenotype derived thereof, were characterized in milk in order to know whether the acquisition of resistance to bile could modify some characteristics of the microorganism. Both strains were able to grow and acidify milk similarly; however the production of ethanol increased at the expense of the aroma compound acetaldehyde in milk fermented by the strain 193+, with respect to milk fermented by the strain 193. Both microorganisms produced a heteropolysaccharide composed of glucose and galactose, and were able to increase the viscosity of fermented milks. In spite of the higher production yield of EPS by the bile-resistant strain 193+, it displayed a lower ability to increase viscosity than Lb. delbrueckii subsp. lactis 193. Milk increased survival in simulated gastric juice; the presence of bile improved adhesion to the intestinal cell line HT29-MTX in both strains. However, the acquisition of a stable resistance phenotype did not improve survival in simulated gastric and intestinal conditions or the adhesion to the intestinal cell line HT29-MTX. Thus, Lb. delbrueckii subsp. lactis 193 presents suitable technological properties for the manufacture of fermented dairy products; the acquisition of a stable bile-resistant phenotype modified some properties of the microorganism. This suggests that the possible use of bile-resistant derivative strains should be

Isolation and characterisation of obligately anaerobic, lipolytic bacteria from the rumen of red deer.

Science.gov (United States)

Jarvis, G N; Strömpl, C; Moore, E R; Thiele, J H

1998-03-01

Two Gram-positive, obligately anaerobic, lipolytic bacteria, isolates LIP4 and LIP5, were obtained from the rumen contents of juvenile red deer. These mesophilic bacterial strains were capable of hydrolysing the neutral lipids, tallow, tripalmitin and oliver oil, into their constituent free long-chain fatty acid and glycerol moieties. The latter compound was dissimilated by both isolates, with isolate LIP4 producing propionate as the predominant product, while isolate LIP5 produced acetate, ethanol and succinate. The lactate-utilising isolate LIP4 grew on a limited range of saccharide substrates including glucose, fructose and ribose, and exhibited an unusual cell wall structure and morphology. The isolate LIP5 grew upon a wider range of saccharides, but was unable to use lactate as a substrate. Based upon phenotypic and 16S rRNA gene sequence analyses, isolate LIP4 clusters with species in the genus Propionibacterium, while isolate LIP5 is a member of clostridial cluster XIVa.

Genomic analysis of thermophilic Bacillus coagulans strains: efficient producers for platform bio-chemicals.

Science.gov (United States)

Su, Fei; Xu, Ping

2014-01-29

Microbial strains with high substrate efficiency and excellent environmental tolerance are urgently needed for the production of platform bio-chemicals. Bacillus coagulans has these merits; however, little genetic information is available about this species. Here, we determined the genome sequences of five B. coagulans strains, and used a comparative genomic approach to reconstruct the central carbon metabolism of this species to explain their fermentation features. A novel xylose isomerase in the xylose utilization pathway was identified in these strains. Based on a genome-wide positive selection scan, the selection pressure on amino acid metabolism may have played a significant role in the thermal adaptation. We also researched the immune systems of B. coagulans strains, which provide them with acquired resistance to phages and mobile genetic elements. Our genomic analysis provides comprehensive insights into the genetic characteristics of B. coagulans and paves the way for improving and extending the uses of this species.

The use of lactic acid-producing, malic acid-producing, or malic acid-degrading yeast strains for acidity adjustment in the wine industry.

Science.gov (United States)

Su, Jing; Wang, Tao; Wang, Yun; Li, Ying-Ying; Li, Hua

2014-03-01

In an era of economic globalization, the competition among wine businesses is likely to get tougher. Biotechnological innovation permeates the entire world and intensifies the severity of the competition of the wine industry. Moreover, modern consumers preferred individualized, tailored, and healthy and top quality wine products. Consequently, these two facts induce large gaps between wine production and wine consumption. Market-orientated yeast strains are presently being selected or developed for enhancing the core competitiveness of wine enterprises. Reasonable biological acidity is critical to warrant a high-quality wine. Many wild-type acidity adjustment yeast strains have been selected all over the world. Moreover, mutation breeding, metabolic engineering, genetic engineering, and protoplast fusion methods are used to construct new acidity adjustment yeast strains to meet the demands of the market. In this paper, strategies and concepts for strain selection or improvement methods were discussed, and many examples based upon selected studies involving acidity adjustment yeast strains were reviewed. Furthermore, the development of acidity adjustment yeast strains with minimized resource inputs, improved fermentation, and enological capabilities for an environmentally friendly production of healthy, top quality wine is presented.

Genetic recombination in auxotrophic strains of Phanerochaete chrysosporium

International Nuclear Information System (INIS)

Krejci, R.

1987-01-01

Four auxotrophic strains of ligninolytic basidiomycete Phanerochaete chrysosporium were obtained by UV mutagenesis. The heterokaryotic mycelium formed by complementation of different auxotrophic isolates was able to fruit and produce basidiospores. Prototrophic strains and strains with a recombined set of parental nutritional requirements were isolated from the basidiospore progeny of the heterokaryons. Genetic recombination hence takes place in fruit bodies produced by the heterokaryotic mycelium. (author). 3 tabs., 13 refs

Potent New Small-Molecule Inhibitor of Botulinum Neurotoxin Serotype A Endopeptidase Developed by Synthesis-Based Computer-Aided Molecular Design

Science.gov (United States)

2009-11-01

simulations; (4) synthesis and evaluation of the molecules from Step 2 or 3 (e.g., synthesizing and testing AHP). From synthetic chemistry point of view...2000) Synthesis of 6H-indolo [2,3-b][1,6]naphthyridines and related compounds as the 5-Aza analogues of ellipticine alkaloids . J Org Chem 65: 7977–7983...Potent New Small-Molecule Inhibitor of Botulinum Neurotoxin Serotype A Endopeptidase Developed by Synthesis -Based Computer-Aided Molecular Design

Crystal structure of the receptor-binding domain of botulinum neurotoxin type HA, also known as type FA or H

OpenAIRE

Yao, G; Lam, KH; Perry, K; Weisemann, J; Rummel, A; Jin, R

2017-01-01

© 2017 by the authors. Licensee MDPI, Basel, Switzerland. Botulinum neurotoxins (BoNTs), which have been exploited as cosmetics and muscle-disorder treatment medicines for decades, are well known for their extreme neurotoxicity to humans. They pose a potential bioterrorism threat because they cause botulism, a flaccid muscular paralysis-associated disease that requires immediate antitoxin treatment and intensive care over a long period of time. In addition to the existing seven established Bo...

Identification and characterization of the surface proteins of Clostridium difficile

International Nuclear Information System (INIS)

Dailey, D.C.

1988-01-01

Several clostridial proteins were detected on the clostridial cell surface by sensitive radioiodination techniques. Two major proteins and six minor proteins comprised the radioiodinated proteins on the clostridial cell surface. Cellular fractionation of surface radiolabeled C. difficile determined that the radioiodinated proteins were found in the cell wall fraction of C. difficile and surprisingly were also present in the clostridial membrane. Furthermore, an interesting phenomenon of disulfide-crosslinking of the cell surface proteins of C. difficile was observed. Disulfide-linked protein complexes were found in both the membrane and cell wall fractions. In addition, the cell surface proteins of C. difficile were found to be released into the culture medium. In attempts to further characterize the clostridial proteins recombinant DNA techniques were employed. In addition, the role of the clostridial cell surface proteins in the interactions of C. difficile with human PMNs was also investigated

Penicillin production by mutant strains of penicillium chrysogenum

International Nuclear Information System (INIS)

Tawfik, Z.S.; Ashour, M.S.; Shihab, A.