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Find video protocols related to scientific articles indexed in Pubmed.
Genetic evidence for the involvement of the S-layer protein gene sap and the sporulation genes spo0A, spo0B, and spo0F in phage AP50c infection of Bacillus anthracis.
J. Bacteriol.
PUBLISHED: 12-20-2013
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In order to better characterize the Bacillus anthracis typing phage AP50c, we designed a genetic screen to identify its bacterial receptor. Mariner transposon insertions or targeted deletions of the structural gene for the S-layer protein Sap and the sporulation genes spo0A, spo0B, and spo0F in B. anthracis Sterne resulted in phage resistance with concomitant defects in phage adsorption and infectivity. Electron microscopy of bacteria incubated with AP50c revealed phage particles associated with the surface of bacilli of the Sterne strain but not with the surfaces of ?sap, ?spo0A, ?spo0B, or ?spo0F mutants. The amount of Sap in the S-layer of each of the spo0 mutant strains was substantially reduced compared to the parent strain, and incubation of AP50c with purified recombinant Sap led to substantial reduction in phage activity. Phylogenetic analysis based on whole genome sequences of B. cereus sensu lato strains revealed several closely-related B. cereus and B. thuringiensis strains that carry sap genes with very high similarities to that of B. anthracis. Complementation of the ?sap mutant in trans with the wild-type B. anthracis sap or the sap gene from either of two different B. cereus strains that are sensitive to AP50c infection restored phage sensitivity, and electron microscopy confirmed attachment of phage particles to the surface of each of the complemented strains. Based on these data, we postulate that Sap is involved in AP50c infectivity, most likely acting as the phage receptor, and that the spo0 genes may regulate synthesis of Sap and/or formation of the S-layer.
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Rapid identification of genetic modifications in Bacillus anthracis using whole genome draft sequences generated by 454 pyrosequencing.
PLoS ONE
PUBLISHED: 05-17-2010
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The anthrax letter attacks of 2001 highlighted the need for rapid identification of biothreat agents not only for epidemiological surveillance of the intentional outbreak but also for implementing appropriate countermeasures, such as antibiotic treatment, in a timely manner to prevent further casualties. It is clear from the 2001 cases that survival may be markedly improved by administration of antimicrobial therapy during the early symptomatic phase of the illness; i.e., within 3 days of appearance of symptoms. Microbiological detection methods are feasible only for organisms that can be cultured in vitro and cannot detect all genetic modifications with the exception of antibiotic resistance. Currently available immuno or nucleic acid-based rapid detection assays utilize known, organism-specific proteins or genomic DNA signatures respectively. Hence, these assays lack the ability to detect novel natural variations or intentional genetic modifications that circumvent the targets of the detection assays or in the case of a biological attack using an antibiotic resistant or virulence enhanced Bacillus anthracis, to advise on therapeutic treatments.
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Genomic comparison of Escherichia coli O104:H4 isolates from 2009 and 2011 reveals plasmid, and prophage heterogeneity, including shiga toxin encoding phage stx2.
PLoS ONE
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In May of 2011, an enteroaggregative Escherichia coli O104:H4 strain that had acquired a Shiga toxin 2-converting phage caused a large outbreak of bloody diarrhea in Europe which was notable for its high prevalence of hemolytic uremic syndrome cases. Several studies have described the genomic inventory and phylogenies of strains associated with the outbreak and a collection of historical E. coli O104:H4 isolates using draft genome assemblies. We present the complete, closed genome sequences of an isolate from the 2011 outbreak (2011C-3493) and two isolates from cases of bloody diarrhea that occurred in the Republic of Georgia in 2009 (2009EL-2050 and 2009EL-2071). Comparative genome analysis indicates that, while the Georgian strains are the nearest neighbors to the 2011 outbreak isolates sequenced to date, structural and nucleotide-level differences are evident in the Stx2 phage genomes, the mer/tet antibiotic resistance island, and in the prophage and plasmid profiles of the strains, including a previously undescribed plasmid with homology to the pMT virulence plasmid of Yersinia pestis. In addition, multiphenotype analysis showed that 2009EL-2071 possessed higher resistance to polymyxin and membrane-disrupting agents. Finally, we show evidence by electron microscopy of the presence of a common phage morphotype among the European and Georgian strains and a second phage morphotype among the Georgian strains. The presence of at least two stx2 phage genotypes in host genetic backgrounds that may derive from a recent common ancestor of the 2011 outbreak isolates indicates that the emergence of stx2 phage-containing E. coli O104:H4 strains probably occurred more than once, or that the current outbreak isolates may be the result of a recent transfer of a new stx2 phage element into a pre-existing stx2-positive genetic background.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.