Bacterial endospores are remarkable examples of biological resilience, representing a dormant and... more Bacterial endospores are remarkable examples of biological resilience, representing a dormant and heavily fortified differentiation form capable of withstanding physical and chemical stressors detrimental to vegetative cells. In pathogenic firmicutes, spores also form an infectious particle and can take up a central role in the environmental persistence and dissemination of disease. A poorly understood aspect of spore-mediated infection is the fibrous structures or ‘endospore appendages’ (ENAs) that have been seen to decorate the spores of pathogenic Bacilli and Clostridia. New methodological approaches are opening an unprecedented window on these long enigmatic structures. Using cryoID, Alphafold modelling and genetic approaches we identify a novel class of ultra-robust ENAs formed byBacillus paranthracis. We demonstrate that L-ENA are encoded by a three-gene cluster (ena3) that contains all components for the self-assembly of ladder-like protein nanofibers of stacked heptameric ri...
Background Enterohemorrhagic Escherichia coli (EHEC) is an emerging health challenge worldwide an... more Background Enterohemorrhagic Escherichia coli (EHEC) is an emerging health challenge worldwide and outbreaks caused by this pathogen poses a serious public health concern. Shiga toxin (Stx) is the major virulence factor of EHEC, and the stx genes are carried by temperate bacteriophages (Stx phages). The switch between lysogenic and lytic life cycle of the phage, which is crucial for Stx production and for severity of the disease, is regulated by the CI repressor which maintain latency by preventing transcription of the replication proteins. Three EHEC phage replication units (Eru1-3) in addition to the classical lambdoid replication region have been described previously, and Stx phages carrying the Eru1 replication region were associated with highly virulent EHEC strains. Results In this study, we have classified the Eru replication region of 419 Stx phages. In addition to the lambdoid replication region and three already described Erus, ten novel Erus (Eru4 to Eru13) were detected....
<p>Immunoblot analysis of whole cell lysates of equal numbers of cells and of equal amounts... more <p>Immunoblot analysis of whole cell lysates of equal numbers of cells and of equal amounts of protein from purified pili. The antibodies used were the PC recognizing TEPC-15 and the PilE peptide specific antibody α-pilin. Strains used were in A) wild-type (N400), <i>pptA</i> (KS9), <i>pilT</i><sub>ind</sub> (12/9/1), <i>pilE</i><sub>ind</sub> (MW24), <i>pilC</i> (KS787), <i>pilC pptA</i> (KS788), <i>pilC pilT</i><sub>ind</sub> (KS789), <i>pilV</i> (KS790), <i>pilV pptA</i> (KS10), <i>pilV pilT</i><sub>ind</sub> (KS791), <i>comP</i> (KS792), <i>comP pptA</i> (KS793), <i>comP pilT</i><sub>ind</sub> (KS794), <i>pilU</i> (KS795), <i>pilU pptA</i> (KS796), <i>pilU pilT</i><sub>ind</sub> (KS798) and in B) wild-type (N400), <i>pilE</i><sub>ind</sub> (KS786), <i>pilH</i> (KS799), <i>pilH pptA</i> (KS800), <i>pilH pilT</i><sub>ind</sub> (KS801), <i>pilI</i> (KS802), <i>pilI pptA</i> (KS803), <i>pilI pilT</i><sub>ind</sub> (KS804), <i>pilJ</i> (KS805), <i>pilJ pptA</i> (KS806), <i>pilJ pilT</i><sub>ind</sub> (KS807), <i>pilK</i> (KS808), <i>pilK pptA</i> (KS809), <i>pilK pilT</i><sub>ind</sub> (KS810), <i>pilL</i> (KS811), <i>pilL pptA</i> (KS812) and <i>pilL pilT</i><sub>ind</sub> (KS813). The faster migrating protein band below pilin is S-pilin (indicated by an arrow), a proteolytic degradation product of PilE that is a correlate of type IV pilus biogenesis defects and which requires <i>pilT</i> expression <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096419#pone.0096419-Wolfgang2" target="_blank">[36]</a>. The strains were grown on standard GC plates without inducer such that the <i>pilT</i><sub>ind</sub> and <i>pilE</i><sub>ind</sub> loci were not expressed. All samples on each blot were run on the same gel and the dotted lines were introduced as guidance facilitating evaluation of the data. Results representative of at least three different experiments are shown.</p
<p>A) Graphical representation of the relative abundance of phospho-form modified PilE comp... more <p>A) Graphical representation of the relative abundance of phospho-form modified PilE compared to total PilE. B) Graphical representation of the relative abundance of various phospho-form- and glycan-modified PilE. The strain used was KS791 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096419#pone.0096419-WintherLarsen1" target="_blank">[35]</a>.</p
Avian pathogenic E. coli (APEC) cause high first week mortality (FWM) in broiler chickens worldwi... more Avian pathogenic E. coli (APEC) cause high first week mortality (FWM) in broiler chickens worldwide. In order to investigate the epidemiologic aspects of colibacillosis in broiler flocks it is important to develop reliable and cost-effective sampling guidelines. In this context, it is particularly important to define the minimum number of samples required to reliably identify the causative APEC clone during outbreaks of colibacillosis. This study describes the diversity of E. coli isolates between and within three flocks with high FWM due to colibacillosis. Each flock was represented by five animals, showing typical lesions of colibacillosis, and spleen, liver and one other organ from each animal was sampled for APEC. A total of 47 E. coli isolates, one per organ, and approximately 15 isolates per flock were whole genome sequenced and compared by multilocus sequence typing (MLST), serotyping and phylogenetic analysis to deduce their relationship. The results revealed that within individual birds there was little or no sequence type (ST) or serotype diversity between APEC isolates from different organs. Based on phylogenetic analysis, isolates belonging to the same ST and serotype showed a low number of single nucleotide polymorphisms (SNPs) across more than 95 % of the genome. Isolates from the liver always represented the major disease-causing APEC in individual birds, even when more than one ST was detected within an individual bird and flock. This study guides us towards an economically efficient way of sampling for future epidemiological studies on colibacillosis, by determining the causative APEC-clone at flock level.
Bacterial endospores are remarkable examples of biological resilience, representing a dormant and... more Bacterial endospores are remarkable examples of biological resilience, representing a dormant and heavily fortified differentiation form capable of withstanding physical and chemical stressors detrimental to vegetative cells. In pathogenic firmicutes, spores also form an infectious particle and can take up a central role in the environmental persistence and dissemination of disease. A poorly understood aspect of spore-mediated infection is the fibrous structures or ‘endospore appendages’ (ENAs) that have been seen to decorate the spores of pathogenic Bacilli and Clostridia. New methodological approaches are opening an unprecedented window on these long enigmatic structures. Using cryoID, Alphafold modelling and genetic approaches we identify a novel class of ultra-robust ENAs formed byBacillus paranthracis. We demonstrate that L-ENA are encoded by a three-gene cluster (ena3) that contains all components for the self-assembly of ladder-like protein nanofibers of stacked heptameric ri...
Background Enterohemorrhagic Escherichia coli (EHEC) is an emerging health challenge worldwide an... more Background Enterohemorrhagic Escherichia coli (EHEC) is an emerging health challenge worldwide and outbreaks caused by this pathogen poses a serious public health concern. Shiga toxin (Stx) is the major virulence factor of EHEC, and the stx genes are carried by temperate bacteriophages (Stx phages). The switch between lysogenic and lytic life cycle of the phage, which is crucial for Stx production and for severity of the disease, is regulated by the CI repressor which maintain latency by preventing transcription of the replication proteins. Three EHEC phage replication units (Eru1-3) in addition to the classical lambdoid replication region have been described previously, and Stx phages carrying the Eru1 replication region were associated with highly virulent EHEC strains. Results In this study, we have classified the Eru replication region of 419 Stx phages. In addition to the lambdoid replication region and three already described Erus, ten novel Erus (Eru4 to Eru13) were detected....
<p>Immunoblot analysis of whole cell lysates of equal numbers of cells and of equal amounts... more <p>Immunoblot analysis of whole cell lysates of equal numbers of cells and of equal amounts of protein from purified pili. The antibodies used were the PC recognizing TEPC-15 and the PilE peptide specific antibody α-pilin. Strains used were in A) wild-type (N400), <i>pptA</i> (KS9), <i>pilT</i><sub>ind</sub> (12/9/1), <i>pilE</i><sub>ind</sub> (MW24), <i>pilC</i> (KS787), <i>pilC pptA</i> (KS788), <i>pilC pilT</i><sub>ind</sub> (KS789), <i>pilV</i> (KS790), <i>pilV pptA</i> (KS10), <i>pilV pilT</i><sub>ind</sub> (KS791), <i>comP</i> (KS792), <i>comP pptA</i> (KS793), <i>comP pilT</i><sub>ind</sub> (KS794), <i>pilU</i> (KS795), <i>pilU pptA</i> (KS796), <i>pilU pilT</i><sub>ind</sub> (KS798) and in B) wild-type (N400), <i>pilE</i><sub>ind</sub> (KS786), <i>pilH</i> (KS799), <i>pilH pptA</i> (KS800), <i>pilH pilT</i><sub>ind</sub> (KS801), <i>pilI</i> (KS802), <i>pilI pptA</i> (KS803), <i>pilI pilT</i><sub>ind</sub> (KS804), <i>pilJ</i> (KS805), <i>pilJ pptA</i> (KS806), <i>pilJ pilT</i><sub>ind</sub> (KS807), <i>pilK</i> (KS808), <i>pilK pptA</i> (KS809), <i>pilK pilT</i><sub>ind</sub> (KS810), <i>pilL</i> (KS811), <i>pilL pptA</i> (KS812) and <i>pilL pilT</i><sub>ind</sub> (KS813). The faster migrating protein band below pilin is S-pilin (indicated by an arrow), a proteolytic degradation product of PilE that is a correlate of type IV pilus biogenesis defects and which requires <i>pilT</i> expression <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096419#pone.0096419-Wolfgang2" target="_blank">[36]</a>. The strains were grown on standard GC plates without inducer such that the <i>pilT</i><sub>ind</sub> and <i>pilE</i><sub>ind</sub> loci were not expressed. All samples on each blot were run on the same gel and the dotted lines were introduced as guidance facilitating evaluation of the data. Results representative of at least three different experiments are shown.</p
<p>A) Graphical representation of the relative abundance of phospho-form modified PilE comp... more <p>A) Graphical representation of the relative abundance of phospho-form modified PilE compared to total PilE. B) Graphical representation of the relative abundance of various phospho-form- and glycan-modified PilE. The strain used was KS791 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096419#pone.0096419-WintherLarsen1" target="_blank">[35]</a>.</p
Avian pathogenic E. coli (APEC) cause high first week mortality (FWM) in broiler chickens worldwi... more Avian pathogenic E. coli (APEC) cause high first week mortality (FWM) in broiler chickens worldwide. In order to investigate the epidemiologic aspects of colibacillosis in broiler flocks it is important to develop reliable and cost-effective sampling guidelines. In this context, it is particularly important to define the minimum number of samples required to reliably identify the causative APEC clone during outbreaks of colibacillosis. This study describes the diversity of E. coli isolates between and within three flocks with high FWM due to colibacillosis. Each flock was represented by five animals, showing typical lesions of colibacillosis, and spleen, liver and one other organ from each animal was sampled for APEC. A total of 47 E. coli isolates, one per organ, and approximately 15 isolates per flock were whole genome sequenced and compared by multilocus sequence typing (MLST), serotyping and phylogenetic analysis to deduce their relationship. The results revealed that within individual birds there was little or no sequence type (ST) or serotype diversity between APEC isolates from different organs. Based on phylogenetic analysis, isolates belonging to the same ST and serotype showed a low number of single nucleotide polymorphisms (SNPs) across more than 95 % of the genome. Isolates from the liver always represented the major disease-causing APEC in individual birds, even when more than one ST was detected within an individual bird and flock. This study guides us towards an economically efficient way of sampling for future epidemiological studies on colibacillosis, by determining the causative APEC-clone at flock level.
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