{"title":"Evolution of YacG to safeguard DNA gyrase from external perturbation","authors":"Priti Biswas , Sugopa Sengupta , Valakunja Nagaraja","doi":"10.1016/j.resmic.2023.104093","DOIUrl":"10.1016/j.resmic.2023.104093","url":null,"abstract":"<div><p>Cells have evolved strategies to safeguard their genome integrity. We describe a mechanism to counter double strand breaks in the chromosome that involves the protection of an essential housekeeping enzyme from external agents. YacG is a DNA gyrase inhibitory protein from <em>Escherichia coli</em><span> that protects the bacterium from the cytotoxic effects of catalytic inhibitors as well as cleavage-complex stabilizers of DNA gyrase. By virtue of blocking the primary DNA binding<span><span> site of the enzyme, YacG prevents the accumulation of double strand breaks induced by gyrase poisons. It also enables the bacterium to resist the growth-inhibitory property of novobiocin. Gyrase poison-induced oxidative stress upregulates YacG production, probably as a cellular response to counter DNA damage. YacG-mediated protection of the genome is specific for gyrase targeting agents as the protection is not observed from the action of general DNA damaging agents. YacG also intensifies the transcription stress induced by rifampicin substantiating the importance of gyrase activity during transcription. Although essential for </span>bacterial survival, DNA gyrase often gets entrapped by external inhibitors and poisons, resulting in cell death. The existence of YacG to specifically protect an essential housekeeping enzyme might be a strategy adopted by bacteria for competitive fitness advantage.</span></span></p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10319890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Myxobacteria: biology and bioactive secondary metabolites","authors":"Sandeep Kaur Saggu , Amar Nath , Shiv Kumar","doi":"10.1016/j.resmic.2023.104079","DOIUrl":"10.1016/j.resmic.2023.104079","url":null,"abstract":"<div><p>Myxobacteria<span> are Gram-negative eubacteria and they thrive in a variety of habitats including soil rich in organic matter, rotting wood, animal dung and marine environment. Myxobacteria are a promising source of new compounds associated with diverse bioactive spectrum and unique mode of action. The genome information of myxobacteria has revealed many orphan biosynthetic pathways indicating that these bacteria can be the source of several novel natural products. In this review, we highlight the biology of myxobacteria with emphasis on their habitat, life cycle, isolation methods and enlist all the bioactive secondary metabolites purified till date and their mode of action.</span></p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10256388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manitosh Pandey , Sakshi Talwar , Rahul Pal , Vaibhav Nain , Sonia Johri , Amit Singhal , Amit Kumar Pandey
{"title":"Transcription factor mce3R modulates antibiotics and disease persistence in Mycobacterium tuberculosis","authors":"Manitosh Pandey , Sakshi Talwar , Rahul Pal , Vaibhav Nain , Sonia Johri , Amit Singhal , Amit Kumar Pandey","doi":"10.1016/j.resmic.2023.104082","DOIUrl":"10.1016/j.resmic.2023.104082","url":null,"abstract":"<div><p>Transcription factors (TFs) of <span><em>Mycobacterium tuberculosis</em></span><span> (Mtb), an etiological agent of tuberculosis, regulate a network of pathways that help prolong the survival of Mtb inside the host. In this study, we have characterized a transcription repressor gene (</span><em>mce3R</em><span>) from the TetR family, that encodes for Mce3R protein in </span><em>Mtb</em>. We demonstrated that the <em>mce3R</em> gene is dispensable for the growth of <em>Mtb</em> on cholesterol. Gene expression analysis suggests that the transcription of genes belonging to the <em>mce3R</em><span> regulon is independent of the carbon source. We found that, in comparison to the wild type, the </span><em>mce3R</em> deleted strain (<em>Δmce3R)</em><span> generated more intracellular ROS and demonstrated reduced susceptibility to oxidative stress. Total lipid analysis suggests that </span><em>mce3R</em> regulon encoded proteins modulate the biosynthesis of cell wall lipids in <em>Mtb</em>. Interestingly, the absence of Mce3R increased the frequency of generation of antibiotic persisters in <em>Mtb</em> and imparted <em>in-vivo</em> growth advantage phenotype in guinea pigs. In conclusion, genes belonging to the <em>mce3R</em> regulon modulate the frequency of generation of persisters in <em>Mtb</em>. Hence, targeting <em>mce3R</em> regulon encoded proteins could potentiate the current regimen by eliminating persisters during <em>Mtb</em> infection.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10269858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruibin Zhang , Yang Luo , Lili Gang , Yanrong Xu , Xin Zhang , Qi Peng , Leyla Slamti , Didier Lereclus , Guirong Wang , Fuping Song
{"title":"Key amino acids residues enhance the ability of CpcR to activate cry gene expression in Bacillus thuringiensis","authors":"Ruibin Zhang , Yang Luo , Lili Gang , Yanrong Xu , Xin Zhang , Qi Peng , Leyla Slamti , Didier Lereclus , Guirong Wang , Fuping Song","doi":"10.1016/j.resmic.2023.104051","DOIUrl":"10.1016/j.resmic.2023.104051","url":null,"abstract":"<div><p>Typical <span><em>Bacillus thuringiensis</em></span><span> (Bt) produces one or more parasporal crystals composed of insecticidal Cry proteins during the sporulation<span>, and the parasporal crystals and spores are produced from the same cell. Strain Bt LM1212 is different from typical Bt strains in that its crystals and spores are produced in different cells. Previous studies have found that the cell differentiation process of Bt LM1212 is related to the transcription factor CpcR which activates the </span></span><em>cry</em>-gene promoters. In addition, CpcR could activate the Bt LM1212 <em>cry35-like</em> gene promoter (P<sub><em>35</em></sub>) when introduced in the heterologous HD73<sup>-</sup> strain. It was shown that P<sub><em>35</em></sub> was only activated in non-sporulating cells. In this study, the peptidic sequences of CpcR homologous proteins found in other strains of the <span><em>Bacillus cereus</em></span> group were used as references to identify two key amino acid sites for CpcR activity. The function of these amino acids was investigated by measuring P<sub><em>35</em></sub> activation by CpcR in strain HD73<sup>-</sup><span>. These results will lay a foundation for the optimization of the insecticidal protein expression system in non-sporulating cells.</span></p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10119045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Linda Huijboom , Marcel Tempelaars , Mingzhen Fan , Yourong Zhu , Sjef Boeren , Erik van der Linden , Tjakko Abee
{"title":"l-tyrosine modulates biofilm formation of Bacillus cereus ATCC 14579","authors":"Linda Huijboom , Marcel Tempelaars , Mingzhen Fan , Yourong Zhu , Sjef Boeren , Erik van der Linden , Tjakko Abee","doi":"10.1016/j.resmic.2023.104072","DOIUrl":"10.1016/j.resmic.2023.104072","url":null,"abstract":"<div><p><em>Bacillus cereus</em> is a food-borne pathogen capable of producing biofilms. Following analysis of biofilm formation by <em>B. cereus</em> ATCC 14579 transposon mutants in defined medium (DM), a deletion mutant of <em>bc2939</em> (Δ<em>bc2939</em>) was constructed that showed decreased crystal violet biofilm staining and biofilm cell counts. In addition, Δ<em>bc2939</em> also produced smaller colony biofilms with lower cell counts and loss of wrinkly morphology. The <em>bc2939</em> gene encodes for Prephenate dehydrogenase, which converts Prephenate to 4-Hydroxy-phenylpyruvate (4-HPPA) in the <span>l</span>-tyrosine branch of the Shikimate pathway. While growth of the mutant and WT in DM was similar, addition of <span>l</span>-tyrosine was required to restore WT-like (colony) biofilm formation. Comparative proteomics showed reduced expression of Tyrosine-protein kinase/phosphatase regulators and extracellular polysaccharide cluster 1 (EPS1) proteins, aerobic electron transfer chain cytochrome <em>aa</em>3/d quinol oxidases, and iso-chorismate synthase involved in menaquinone synthesis in DM grown mutant biofilm cells, while multiple oxidative stress-related catalases and superoxide dismutases were upregulated. Performance in shaking cultures showed a 100-fold lower concentration of menaquinone-7 and reduction in cell counts of DM grown Δ<em>bc2939</em> indicating increased oxygen sensitivity. Combining all results, points to an important role of Tyrosine-modulated EPS1 production and menaquinone-dependent aerobic respiration in <em>B</em>. cereus ATCC 14579 (colony) biofilm formation.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10053628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zoë R. Barandongo , Amélie C. Dolfi , Spencer A. Bruce , Kristyna Rysava , Yen-Hua Huang , Hendrina Joel , Ayesha Hassim , Pauline L. Kamath , Henriette van Heerden , Wendy C. Turner
{"title":"The persistence of time: the lifespan of Bacillus anthracis spores in environmental reservoirs","authors":"Zoë R. Barandongo , Amélie C. Dolfi , Spencer A. Bruce , Kristyna Rysava , Yen-Hua Huang , Hendrina Joel , Ayesha Hassim , Pauline L. Kamath , Henriette van Heerden , Wendy C. Turner","doi":"10.1016/j.resmic.2023.104029","DOIUrl":"10.1016/j.resmic.2023.104029","url":null,"abstract":"<div><p><span>Anthrax is a lethal bacterial zoonosis primarily affecting herbivorous wildlife and livestock. Upon host death </span><span><em>Bacillus anthracis</em></span><span><span> vegetative cells form spores capable of surviving for years in soil. Anthrax transmission requires host exposure to large spore doses. Thus, conditions that facilitate higher spore concentrations or promote spore survival will increase the probability that a pathogen reservoir infects future hosts. We investigated abiotic and pathogen genomic variation in relation to spore concentrations in surface soils (0–1 cm depth) at 40 </span>plains zebra </span><em>(Equus quagga)</em><span> anthrax carcass<span> sites in Namibia. Specifically, how initial spore concentrations and spore survival were affected by seasonality associated with the timing of host mortality, local soil characteristics, and pathogen genomic variation. Zebras dying of anthrax in wet seasons—the peak season for anthrax in Etosha National Park—had soil spore concentrations 1.36 orders of magnitude higher than those that died in dry seasons. No other variables considered affected spore concentrations, and spore survival rates did not differ among sites. Surface soils at these pathogen reservoirs remained culture positive for a range of 3.8–10.4 years after host death. Future research could evaluate if seasonal patterns in spore concentrations are driven by differences in sporulation success or levels of terminal bacteremia.</span></span></p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10060223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alicia Nevers , Markus Kranzler , Stéphane Perchat , Michel Gohar , Alexei Sorokin , Didier Lereclus , Monika Ehling-Schulz , Vincent Sanchis-Borja
{"title":"Plasmid – Chromosome interplay in natural and non-natural hosts: global transcription study of three Bacillus cereus group strains carrying pCER270 plasmid","authors":"Alicia Nevers , Markus Kranzler , Stéphane Perchat , Michel Gohar , Alexei Sorokin , Didier Lereclus , Monika Ehling-Schulz , Vincent Sanchis-Borja","doi":"10.1016/j.resmic.2023.104074","DOIUrl":"10.1016/j.resmic.2023.104074","url":null,"abstract":"<div><p>The <span><em>Bacillus cereus</em></span> group comprises genetically related Gram-positive spore-forming bacteria that colonize a wide range of ecological niches and hosts. Despite their high degree of genome conservation, extrachromosomal genetic material diverges between these species. The discriminating properties of the <em>B. cereus</em><span> group strains are mainly due to plasmid-borne toxins, reflecting the importance of horizontal gene transfers in bacterial evolution and species definition. To investigate how a newly acquired megaplasmid can impact the transcriptome of its host, we transferred the pCER270 from the emetic </span><em>B. cereus</em> strains to phylogenetically distant <em>B. cereus</em><span> group strains. RNA-sequencing experiments allowed us to determine the transcriptional influence of the plasmid on host gene expression and the impact of the host genomic background on the pCER270 gene expression. Our results show a transcriptional cross-regulation between the megaplasmid and the host genome. pCER270 impacted carbohydrate metabolism<span> and sporulation genes expression, with a higher effect in the natural host of the plasmid, suggesting a role of the plasmid in the adaptation of the carrying strain to its environment. In addition, the host genomes also modulated the expression of pCER270 genes. Altogether, these results provide an example of the involvement of megaplasmids in the emergence of new pathogenic strains.</span></span></p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10060815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carine Mouawad , Mireille Kallassy Awad , Samuel Liegeois , Dominique Ferrandon , Vincent Sanchis-Borja , Laure El Chamy
{"title":"The NF-κB factor Relish is essential for the epithelial defenses protecting against δ-endotoxin dependent effects of Bacillus thuringiensis israelensis infection in the Drosophila model","authors":"Carine Mouawad , Mireille Kallassy Awad , Samuel Liegeois , Dominique Ferrandon , Vincent Sanchis-Borja , Laure El Chamy","doi":"10.1016/j.resmic.2023.104089","DOIUrl":"10.1016/j.resmic.2023.104089","url":null,"abstract":"<div><p><span><em>Bacillus thuringiensis israelensis</em></span> is largely regarded as the most selective, safe and ecofriendly biopesticide used for the control of insect vectors of human diseases. <em>Bti</em><span> enthomopathogenicity relies on the Cry and Cyt δ-endotoxins, produced as crystalline inclusions during sporulation. Insecticidal selectivity of </span><em>Bti</em> is mainly ascribed to the binding of the Cry toxins to receptors in the gut of target insects. However, the contribution of epithelial defenses in limiting <em>Bti</em> side effects in non-target species remains largely unexplored. Here, taking advantage of the genetically tractable <span><em>Drosophila melanogaster</em></span> model and its amenability for deciphering highly conserved innate immune defenses, we unravel a central role of the NF-κB factor Relish in the protection against the effects of ingested <em>Bti</em><span> spores in a non-susceptible host. Intriguingly, our data indicate that the </span><em>Bti</em><span>-induced Relish response is independent of its canonical activation downstream of peptidoglycan<span> sensing and does not involve its longstanding role in the regulation of antimicrobial peptides encoding genes. In contrast, our data highlight a novel enterocyte specific function of Relish that is essential for preventing general septicemia following </span></span><em>Bti</em> oral infections strictly when producing δ-endotoxins. Altogether, our data provide novel insights into <em>Bti</em>-hosts interactions of prominent interest for the optimization and sustainability of insects’ biocontrol strategies.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10066795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria Vittoria , Anella Saggese , Giovanni Di Gregorio Barletta , Stefany Castaldi , Rachele Isticato , Loredana Baccigalupi , Ezio Ricca
{"title":"Sporulation efficiency and spore quality in a human intestinal isolate of Bacillus cereus","authors":"Maria Vittoria , Anella Saggese , Giovanni Di Gregorio Barletta , Stefany Castaldi , Rachele Isticato , Loredana Baccigalupi , Ezio Ricca","doi":"10.1016/j.resmic.2023.104030","DOIUrl":"10.1016/j.resmic.2023.104030","url":null,"abstract":"<div><p>Bacteria classified as <em>Bacillus cereus sensu stricto</em> cause two different type of gastrointestinal diseases associated with food poisoning<em>.</em> Outbreaks of this opportunistic pathogen are generally due to the resistance of its spores to heat, pH and desiccation that makes hard their complete inactivation from food products. <em>B. cereus</em> is commonly isolated from a variety of environments, including intestinal samples of infected and healthy people. We report the genomic and physiological characterization of MV19, a human intestinal strain closely related (ANI value of 98.81%) to the reference strain <em>B. cereus</em> ATCC 14579. MV19 cells were able to grow in a range of temperatures between 20 and 44 °C. At the optimal temperature the sporulation process was rapidly induced and mature spores efficiently released, however these appeared structurally and morphologically defective. At the sub-optimal growth temperature of 25 °C sporulation was slow and less efficient but a high total number of fully functional spores was produced. These results indicate that the reduced rapidity and efficiency of sporulation at 25 °C are compensated by a high quality and quantity of released spores, suggesting the relevance of different performances at different growth conditions for the adaptation of this bacterium to diverse environmental niches.</p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10418649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solène Fastenackels , Michèle Mock , Jean-Nicolas Tournier , Pierre L. Goossens
{"title":"Early expression of capsule during Bacillus anthracis germination","authors":"Solène Fastenackels , Michèle Mock , Jean-Nicolas Tournier , Pierre L. Goossens","doi":"10.1016/j.resmic.2023.104054","DOIUrl":"10.1016/j.resmic.2023.104054","url":null,"abstract":"<div><p><span><em>Bacillus anthracis</em></span><span> is a spore-forming bacterium that produces two major virulence factors, a tripartite toxin with two enzymatic toxic activities and a pseudo-proteic capsule. One of the main described functions of the poly-gamma-</span><span>d</span>-glutamate capsule is to enable <em>B. anthracis</em><span> bacilli to escape phagocytosis<span>. Thus, kinetics of expression of the capsule filaments at the surface of the emerging bacillus during germination is an important step for the protection of the nascent bacilli. In this study, through immunofluorescence and electron microscopic approaches, we show the emergence of the capsule through a significant surface of the exosporium in the vast majority of the germinating spores, with co-detection of BclA and capsular material. This suggests that, due to an early capsule expression, the extracellular life of </span></span><em>B. anthracis</em><span> might occur earlier than previously thought, once germination is triggered. This raises the prospect that an anti-capsular vaccine may play a protective role at the initial stage of infection by opsonisation of the nascent encapsulated bacilli before their emergence from the exosporium.</span></p></div>","PeriodicalId":21098,"journal":{"name":"Research in microbiology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10418689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}