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Turbid plaques produced by phages of strain 6811 (0.1 ml of concentrated phage suspension) on strain A028.
Source publication
Twenty strains of Clostridium botulinum type C, including 12 isolates from avian sources with varying toxigenic properties, were examined by electron microscope for the presence of bacteriophages. All toxigenic strains were infected with one or two types of phages. Three types of phages designated large, small, and intermediate were observed. Most...
Citations
... Botulinum neurotoxin (BoNT) serotypes C and D and their mosaic variants CD and DC cause severe cases of botulism in animal husbandry and wildlife [7]. The neurotoxin genes of C. botulinum type C and D are carried by bacteriophages, which express unstable lysogeny and are frequently lost during cultivation [8,19,20,26]. BoNT is produced as single-chain peptides with a molecular mass of about 150 kDa which are proteolytically activated into a light chain (approximately 50 kDa) and a heavy chain (approximately 100 kDa) linked by a disulfide bond. The heavy chain is further divided into two domains, an amino-terminal (H N ) and a carboxyl-terminal (H C ) domain [15,23]. ...
Clostridium botulinum types C and D are related to animal botulism. The disease has been reported in sheep in western Sudan causing economic losses. However, the BoNTs that cause sheep botulism in Sudan have not yet subjected to genetic characterization. The aim of this study is to perform genetic analysis for sheep botulism-related isolates from recent outbreak between January to May 2013 at western Sudan in order to improve the efficiency of control strategies and vaccine development. In this study isolation of Clostridium botulinum from sheep samples was obtained by culture methods and mouse bioassay. Positive samples were confirmed by PCR and DNA sequencing. PCR was used to amplify the BoNTs gene using three sets of primers to differentiate the gene of the mosaic type from the conserved genes of type C and D. The results of polymerase chain reaction with these primers indicated that sheep botulism-related isolates possess the gene for the mosaic form of the neurotoxin. PCR products were sequenced and subjected to genetic analysis. The results provided evidence for close relationships and genetic variation of the isolates and reference strains published on the GenBank. Multiple sequence alignments showed numerous substitutions occurred in heavy chain in the most homologous regions of BoNT/CD and in the light chain of toxin type C and D, respectively. Following sequencing, isolates were compared phylogenetically with reference strains. The close genetic relationship to the strain 193_09 and strain: OFD16 suggests that neurotoxins produced from sheep botulism is BoNT type DC. The present study provides information on genetic classification of BoNTs related to sheep botulism isolates in Sudan.
... Production of the botulinum toxin may also be controlled by genes localized in the genome of a temperate bacteriophage [109]. Analysis of 20 Clostridium botulinum type C isolates (including 12 avian ones), which varied in toxigenicity, showed that all toxigenic isolates carried phages of one or two types differing in particle morphology. ...
The review considers the involvement of bacteriophages in transferring genes, which determine bacterial pathogenicity, and the increasing role of comparative genomics and genetics of bacteria and bacteriophages in detecting new cases of horizontal gene transfer. Examples of phage participation in this process proved to a different extent are described. Emphasis is placed on the original work carried out in Russia and focused on bacteriophages (temperate transposable phages and giant virulent phi KZ-like phages) of conditional pathogen Pseudomonas aeruginosa. Consideration is given to the possible lines of further research of the role of bacteriophages in the infection process and, in particular, the role of virulent phages, whose products are similar to those of pathogenic bacteria, in modification of clinical signs of infectious diseases and in evolution. An attempt is made to predict the possible direction of pathogen evolution associated with development of new treatment strategies and generation of new specific niches.
... So suspect were these findings that fresh rockfish fillets from a local market were homogenized and inoculated in a second MS and incubated under vacuum at 30 ° C~ yet again growth was not observed. The biology of this phenomena may be related to bacteriocins produce by non-toxigenic strains of C. botulinum (Beerens and Tahon, 1966;Kautter et al., 1966;Ellison and Kautter, 1970;Anastasio et al., 1971;Lau et al. 1974), to toxigenic properties directed by bacteriophages (Hariharan and Mitchell, 1976;Oguma et al., 1976;Eklund and Poysky, 1981;Iida and Oguma, 1981), or other bacteria which are bacterio-or sporostatic (Wentz et al., 1967;Smith, 1975;Moberg and Sugiyama, 1979). ...
Modified atmosphere packaging of fresh fish is used to market high quality products in some European countries. The potential risk of C. botulinum growth in these extended shelf-life foods is still a concern; especially since toxigenesis may precede organoleptic spoilage. This paper will present toxigenic data from rockfish, salmon and sole muscle tissues which were inoculated with a pool of non-proteolytic C. botulinum type E at seven levels (10(-2)-10(4) spores/sample), and stored under vacuum and 100% CO2, at incubation temperatures between 30 and 4 degrees C, for up to 60 days. Factorial experimental design allowed predictive formulae to be developed able to describe the lag time prior to C. botulinum toxigenesis and the probability of one spore to initiate toxigenesis based upon the storage conditions. Accurate characterization of the microbial ecology of C. botulinum in modified atmosphere-packaged fish, will support safe exploitation of these packaging systems in the market place, and identify critical control points for potential product or process abuses.
... So suspect were these findings that fresh rockfish fillets from a local market were homogenized and inoculated in a second MS and incubated under vacuum at 30 ° C~ yet again growth was not observed. The biology of this phenomena may be related to bacteriocins produce by non-toxigenic strains of C. botulinum (Beerens and Tahon, 1966;Kautter et al., 1966;Ellison and Kautter, 1970;Anastasio et al., 1971;Lau et al. 1974), to toxigenic properties directed by bacteriophages (Hariharan and Mitchell, 1976;Oguma et al., 1976;Eklund and Poysky, 1981;Iida and Oguma, 1981), or other bacteria which are bacterio-or sporostatic (Wentz et al., 1967;Smith, 1975;Moberg and Sugiyama, 1979). ...
Modified atmosphere packaging of fresh fish is used to market high quality products in some European countries. The potential risk of C. botulinum growth in these extended shelf-life foods is still a concern; especially since toxigenesis may precede organoleptic spoilage. This paper will present toxigenic data from rockfish, salmon and sole muscle tissues which were inoculated with a pool of non-proteolytic C. botulinum type E at seven levels (10 2-104 spores/sample), and stored under vacuum and 100% CO2, at incubation temperatures between 30 and 4 ° C, for up to 60 days. Factorial experimental design allowed predictive formulae to be developed able to describe the lag time prior to C. botulinum toxigenesis and the probability of one spore to initiate toxigenesis based upon the storage conditions. Accurate characterization of the microbial ecology of C. botulinum in modified atmosphere-packaged fish, will support safe exploitation of these packaging systems in the market place, and identify critical control points for potential product or process abuses.
... Morphologically similar tox+ phages for C1 and D toxins fall into three antigenic groups, whose members productively lysogenize only those strains which have the receptors needed for phage attachment (150). However, other factors play a role since some antigenically dissimilar phages can convert the same cultures (78). tox+ phage can absorb to but not convert certain cultures to toxin production (151). ...
... Converted cultures produce different levels of toxin. Toxigenic cultures recovered from a lysogenizing incubation that results in extensive cell lysis produce less toxin than cultures from treatments resulting in minimum lysis (78). A culture converted by tox+ phage that has been passed repeatedly through its nontoxic indicator culture produces less toxin than a culture converted by phage which has had fewer such passages (147). ...
... Release of Acetylcholine When toxin acts on an NMJ being stimulated indirectly at a constant level, the amplitudes of the endplate potentials and muscle contractions which are evoked become progressively smaller, paralysis occurs when the nerve action potential no longer elicits a significant endplate potential (27,78). The toxin reduces the frequency of miniature endplate potentials (mepp) even before it affects the endplate potential amplitudes and by the time that the full effects of the toxin have developed, mepp are at very low frequency (18,36) or are completely abolished (32,131). ...
Clostridium botulinum, a polyphyletic Gram-positive taxon of bacteria, is classified purely by their ability to produce botulinum neurotoxin (BoNT). BoNT is the primary virulence factor and the causative agent of botulism. A potentially fatal disease, botulism is classically characterized by a symmetrical descending flaccid paralysis, which is left untreated can lead to respiratory failure and death. Botulism cases are classified into three main forms dependent on the nature of intoxication; foodborne, wound and infant. The BoNT, regarded as the most potent biological substance known, is a zinc metalloprotease that specifically cleaves SNARE proteins at neuromuscular junctions, preventing exocytosis of neurotransmitters, leading to muscle paralysis. The BoNT is now used to treat numerous medical conditions caused by overactive or spastic muscles and is extensively used in the cosmetic industry due to its high specificity and the exceedingly small doses needed to exert long-lasting pharmacological effects. Additionally, the ability to form endospores is critical to the pathogenicity of the bacteria. Disease transmission is often facilitated via the metabolically dormant spores that are highly resistant to environment stresses, allowing persistence in the environment in unfavourable conditions. Infant and wound botulism infections are initiated upon germination of the spores into neurotoxin producing vegetative cells, whereas foodborne botulism is attributed to ingestion of preformed BoNT. C. botulinum is a saprophytic bacterium, thought to have evolved its potent neurotoxin to establish a source of nutrients by killing its host.
Bacterial viruses (bacteriophages, phages) of the gut have increasingly become a focus in microbiome studies, with an understanding that they are likely key players in health and disease. However, characterization of the virome remains largely based on bioinformatic approaches, with the impact of these viromes inferred based on a century of knowledge from aerobic phage work. Studying the phages infecting anaerobes is difficult, as they are often technically demanding to isolate and propagate. In this review, we primarily discuss the phages infecting three well-studied anaerobes in the gut: Bifidobacterium, Clostridia and Bacteroides, with a particular focus on the challenges in isolating and characterizing these phages. We contrast the lessons learned from these to other anaerobic work on phages infecting facultative anaerobes of the gut: Enterococcus and Lactobacillus. Phages from the gut do appear to adhere to the lessons learned from aerobic work, but the additional challenges of working on them has required ingenious new approaches to enable their study. This, in turn, has uncovered remarkable biology likely underpinning phage-host relationships in many stable environments.
Abstract Antibiotic resistance genes (ARGs) are ubiquitous among microorganisms living in a wide variety of environments and can be detected by several molecular techniques. Similarly, toxins and genes encoding toxins are also widespread among organisms. Bacteriophages are bacterial viruses found wherever bacteria exist, and their concentration is particularly high in aquatic environments.
The age of the “omics” truly revolutionized this field, establishing the phylogenetic affiliation and function of phages, as well as the role they play in microbial communities and horizontal transfer of bacterial genes. Genomics, transcriptomics, proteomics, and metabolomics have highlighted the role of phages and their interaction with bacterial populations. It is now generally accepted that horizontal gene
transfer regularly occurs between bacteriophages and their hosts, either by generalized or specialized transductions or possibly by controlling certain bacterial populations of donors or recipients. This means that phages not only play a major role driving bacterial evolution but also influence their own evolution. Phage infection can result in the bacterial host quickly acquiring (or loosing) novel genes
and thus biochemical properties, a process otherwise extremely slow that usually requires long periods of time. This chapter will focus on the role of bacteriophages in the transfer of both antibiotic resistance genes and genes encoding novel toxins to new bacterial species. This knowledge is essential not only to understand the current challenges experienced in medicine but also to prevent, or at least lessen, future
clinically relevant threats resulting from gene transfer between microorganisms
Clostridium botulinum types C and D toxin production is governed by the specific bacteriophages. A type C phage, c-st, was isolated from a toxigenic strain of C-Stockholm, and its whole genome sequence was determined. The genome was a linear double-stranded 185, 681 by DNA with a G+C content of 26.2%, and identical 403-bp sequences were found at each end of the genome. From the DNA research, 198 potential protein-coding regions (ORFs) were identified. The genes for type C progenitor toxin and C3 exoenzyme were identified, but no type D toxin gene was found.A number of genes were homologous to those of a Bacillus subtilis bacteriophage, SPβ. On Southern blot analysis between type C and D cell DNAs and the specific probes for H and L chains of C and D neurotoxins, it became clear that type C and D strains posses only one type of toxin gene. From these findings, it is concluded that cross-neutralization observed between toxins (types C and D) and their antiserums can be caused by the common-antigens in C and D toxins.
