Microbiology-Sgm最新文献

{"title":"Modelling host-pathogen interactions: <i>Galleria mellonella</i> as a platform to study <i>Pseudomonas aeruginosa</i> response to host-imposed zinc starvation.","authors":"Emma Michetti, Tulasi Abinya Mandava, Valerio Secli, Francesca Pacello, Andrea Battistoni, Serena Ammendola","doi":"10.1099/mic.0.001524","DOIUrl":"10.1099/mic.0.001524","url":null,"abstract":"<p><p>Nutritional immunity, a key component of the vertebrate innate immune response, involves the modulation of zinc availability to limit the growth of pathogens. <i>Pseudomonas aeruginosa</i> counteracts host-imposed zinc starvation through metabolic adaptations, including reprogramming of gene expression and activating efficient metal uptake systems. To unravel how zinc shortage contributes to the complexity of bacterial adaptation to the host environment, it is critical to use model systems that mimic fundamental features of <i>P. aeruginosa</i>-related diseases in humans. Among available animal models, <i>Galleria mellonella</i> has recently emerged as a promising alternative to mammalian hosts. This study aims to evaluate whether <i>G. mellonella</i> can recapitulate the zinc-related nutritional immunity responses observed in mammalian infections. Our results show that, upon <i>P. aeruginosa</i> infection, the larvae upregulate several zinc transporters, suggesting an active redistribution of the metal in response to the pathogen. Additionally, <i>P. aeruginosa</i> colonizing the larvae induces Zn uptake regulator-controlled genes, consistent with bacterial adaptation to zinc starvation. Disruption of bacterial zinc uptake capability significantly reduces <i>P. aeruginosa</i> virulence, underscoring the importance of zinc acquisition in pathogenesis also within this model host. As a proof of concept, we also demonstrate that this <i>in vivo</i> model can serve as a viable preliminary screening tool to unveil novel players involved in <i>P. aeruginosa</i> response to zinc starvation, offering valuable insights into the host-pathogen battle for micronutrients.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11753293/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143014983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbe Profile: <i>Salmonella</i> Typhimurium: the master of the art of adaptation.","authors":"Blanca M Perez-Sepulveda, Jay C D Hinton","doi":"10.1099/mic.0.001521","DOIUrl":"10.1099/mic.0.001521","url":null,"abstract":"<p><p><i>Salmonella</i> Typhimurium is a major <i>Salmonella</i> serovar that is found globally. It is responsible for outbreaks of self-limiting gastroenteritis that are broadly linked to the industrialization of food production. <i>S</i>. Typhimurium is a pathogen with a broad host range and remarkable metabolic versatility. The ∼5 Mb genome includes the pSLT virulence plasmid and has a characteristic prophage repertoire. The major virulence determinants are encoded by a variety of pathogenicity islands. Emerging multidrug-resistant lineages of epidemics of <i>S</i>. Typhimurium are currently causing bloodstream infections in sub-Saharan Africa. The versatility and adaptability of <i>S</i>. Typhimurium pose an important public health challenge.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142957849","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":"The <i>Pseudomonas aeruginosa sphBC</i> genes are important for growth in the presence of sphingosine by promoting sphingosine metabolism.","authors":"Pauline DiGianivittorio, Lauren A Hinkel, Jacob R Mackinder, Kristin Schutz, Eric A Klein, Matthew J Wargo","doi":"10.1099/mic.0.001520","DOIUrl":"10.1099/mic.0.001520","url":null,"abstract":"<p><p>Sphingoid bases, including sphingosine, are important components of the antimicrobial barrier at epithelial surfaces where they can cause growth inhibition and killing of susceptible bacteria. <i>Pseudomonas aeruginosa</i> is a common opportunistic pathogen that is less susceptible to sphingosine than many Gram-negative bacteria. Here, we determined that the deletion of the <i>sphBCD</i> operon reduced growth in the presence of sphingosine. Using deletion mutants, complementation and growth assays in <i>P. aeruginosa</i> PAO1, we determined that the <i>sphC</i> and <i>sphB</i> genes, encoding a periplasmic oxidase and periplasmic cytochrome c, respectively, were important for growth on sphingosine, while <i>sphD</i> was dispensable under these conditions. Deletion of <i>sphBCD</i> in <i>P. aeruginosa</i> PA14, <i>Pseudomonas protegens</i> Pf-5 and <i>Pseudomonas fluorescens</i> Pf01 also showed reduced growth in the presence of sphingosine. The <i>P. aeruginosa sphBC</i> genes were also important for growth in the presence of two other sphingoid bases, phytosphingosine and sphinganine. In WT <i>P. aeruginosa</i>, sphingosine is metabolized to an unknown non-inhibitory product, as sphingosine concentrations drop in the culture. However, in the absence of <i>sphBC</i>, sphingosine accumulates, pointing to SphC and SphB as having a role in sphingosine metabolism. Finally, the metabolism of sphingosine by WT <i>P. aeruginosa</i> protected susceptible cells from full growth inhibition by sphingosine, pointing to a role for sphingosine metabolism as a public good. This work shows that the metabolism of sphingosine by <i>P. aeruginosa</i> presents a novel pathway by which bacteria can alter host-derived sphingolipids, but it remains an open question whether SphB and SphC act directly on sphingosine.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142957850","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":"Microbial Primer: Microbiome and thermal tolerance - a new frontier in climate resilience?","authors":"Jingdi Li, Kayla King","doi":"10.1099/mic.0.001523","DOIUrl":"10.1099/mic.0.001523","url":null,"abstract":"<p><p>Microbiome-animal host symbioses are ubiquitous in nature. Animal-associated microbiomes can play a crucial role in host physiology, health and resilience to environmental stressors. As climate change drives rising global temperatures and increases the frequency of thermal extremes, microbiomes are emerging as a new frontier in buffering vulnerable animals against temperature fluctuations. In this primer, we briefly introduce key concepts of microbiome-host symbiosis and microbial responses to temperature shifts. We then summarize the current evidence and understanding of how microbes can buffer the thermal stress faced by their hosts. We identify key challenges for future research. Finally, we emphasize the potential of harnessing microbiomes to improve conservation strategies in a rapidly changing climate, offering a concise overview of this evolving field.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"171 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11750044/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143014971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbe Profile: <i>Candida glabrata</i> - a master of deception.","authors":"Maria Granada, Emily Cook, Gavin Sherlock, Frank Rosenzweig","doi":"10.1099/mic.0.001518","DOIUrl":"10.1099/mic.0.001518","url":null,"abstract":"<p><p><i>Candida glabrata</i> is a fungal microbe associated with multiple vertebrate microbiomes and their terrestrial environments. In humans, the species has emerged as an opportunistic pathogen that now ranks as the second-leading cause of candidiasis in Europe and North America (Beardsley <i>et al</i>. <i>Med Mycol</i> 2024, 62). People at highest risk of infection include the elderly, immunocompromised individuals and/or long-term residents of hospital and assisted-living facilities. <i>C. glabrata</i> is intrinsically drug-resistant, metabolically versatile and able to avoid detection by the immune system. Analyses of its 12.3 Mb genome indicate a stable pangenome Marcet-Houben <i>et al</i>. (<i>BMC Biol</i> 2022, 20) and phylogenetic affinity with <i>Saccharomyces cerevisiae</i>. Recent phylogenetic analyses suggest reclassifying <i>C. glabrata</i> as <i>Nakaseomyces glabratus</i> Lakashima and Sugita (<i>Med Mycol J</i> 2022, 63: 119-132).</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 11","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142717595","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":"Fluoride and gallein regulate polyphosphate accumulation in dental caries-associated <i>Lacticaseibacillus</i>.","authors":"Subhrangshu Mandal, Beverly E Flood, Mark Lunzer, Dhiraj Kumar, Jake V Bailey","doi":"10.1099/mic.0.001519","DOIUrl":"10.1099/mic.0.001519","url":null,"abstract":"<p><p>Inorganic polyphosphates (polyPs) are energy-storing biopolymers synthesized by all three domains of life. PolyP accumulation has been well studied with respect to its role in stress response, but its role in dental disease has received less attention. Dental decay can be promoted by changes in pH as well as the chemical activity of ions such as phosphate in oral fluids at the enamel interface. Previous work has shown that the drawdown of phosphate from biofilm fluids can alter the saturation state of oral fluids to thermodynamically favour mineral dissolution. The members of the Lactobacillaceae are known to accumulate polyP and play a role in early-stage and late-stage dental caries. In this study, we examined the effects of potential metabolic inhibitors on polyP accumulation in <i>Lacticaseibacillus rhamnosus</i>. We observed that two inhibitors of the enzyme responsible for polyP synthesis, gallein and fluoride, inhibited polyP accumulation in a balanced medium. However, fluoride and gallein treatments amended with either glucose or lactate were found to enhance polyP accumulation. These results illustrate the potential complexity of polyP metabolism in the oral environment.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 11","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11604172/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142741166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of excess manganese stress response highlights the central role of manganese exporter Mnx for holding manganese homeostasis in the cyanobacterium <i>Synechocystis</i> sp. PCC 6803.","authors":"Mara Reis, Sanja Zenker, Prisca Viehöver, Karsten Niehaus, Andrea Bräutigam, Marion Eisenhut","doi":"10.1099/mic.0.001515","DOIUrl":"10.1099/mic.0.001515","url":null,"abstract":"<p><p>Cellular levels of the essential micronutrient manganese (Mn) need to be carefully balanced within narrow borders. In cyanobacteria, a sufficient Mn supply is critical for ensuring the function of the oxygen-evolving complex as the central part of the photosynthetic machinery. However, Mn accumulation is fatal for the cells. The reason for the observed cytotoxicity is unclear. To understand the causality behind Mn toxicity in cyanobacteria, we investigated the impact of excess Mn on physiology and global gene expression in the model organism <i>Synechocystis</i> sp. PCC 6803. We compared the response of the WT and the knock-out mutant in the <i>Mn</i> e<i>x</i>porter (Mnx), ∆<i>mnx</i>, which is disabled in the export of surplus Mn and thus functions as a model for toxic Mn overaccumulation. While growth and pigment accumulation in ∆<i>mnx</i> were severely impaired 24 h after the addition of tenfold Mn, the WT was not affected and thus mounted an adequate transcriptional response. RNA-seq data analysis revealed that the Mn stress transcriptomes partly resembled an iron limitation transcriptome. However, the expression of iron limitation signature genes <i>isiABDC</i> was not affected by the Mn treatment, indicating that Mn excess is not accompanied by iron limitation in <i>Synechocystis</i>. We suggest that the ferric uptake regulator, Fur, gets partially mismetallated under Mn excess conditions and thus interferes with an iron-dependent transcriptional response. To encounter mismetallation and other Mn-dependent problems on a protein level, the cells invest in transcripts of ribosomes, proteases and chaperones. In the case of the ∆<i>mnx</i> mutant, the consequences of the disability to export excess Mn from the cytosol manifest in additionally impaired energy metabolism and oxidative stress transcriptomes with a fatal outcome. This study emphasizes the central importance of Mn homeostasis and the transporter Mnx's role in restoring and holding it.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 11","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11649195/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142607257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent responses of the native grassland soil microbiome to heavy grazing between spring and fall.","authors":"Newton Z Lupwayi, Xiying Hao, Monika A Gorzelak","doi":"10.1099/mic.0.001517","DOIUrl":"10.1099/mic.0.001517","url":null,"abstract":"<p><p>Grasslands are estimated to cover about 40% of the earth's land area and are primarily used for grazing. Despite their importance globally, there is a paucity of information on long-term grazing effects on the soil microbiome. We used a 68-year-old grazing experiment to determine differences in the soil permanganate-oxidizable C (POXC), microbial biomass C (MBC), the soil prokaryotic (bacterial and archaeal) community composition and enzyme activities between no-grazing, light grazing and heavy grazing, i.e. 0, 1.2 and 2.4 animal unit months (AUM) ha^-1. The grazing effects were determined in spring and fall grazing. Light grazing had little effect on soil MBC and the composition and diversity of prokaryotic communities in either grazing season, but the effects of heavy grazing depended on the grazing season. In spring, heavy grazing increased the relative abundances of copiotrophic phyla <i>Actinomycetota, Bacillota</i> and <i>Nitrososphaerota</i>, along with soil POXC contents but decreased those of oligotrophic phyla <i>Acidobacteriota, Verrucomicrobiota</i> and <i>Nitrospirota</i>. This difference in responses was not observed in fall, when grazing reduced soil POXC, MBC and the relative abundances of most phyla. The <i>β</i>-diversity analysis showed that the prokaryotic community structure under heavy grazing was different from those in the control and light grazing treatments, and <i>α</i>-diversity indices (except the Shannon index) were highest under heavy grazing in both grazing seasons. The activities of P-mobilizing and S-mobilizing soil enzymes decreased with increasing cattle stocking rate in both seasons, but the activities of the enzymes that mediate C and N cycling decreased only in the fall. The genus <i>RB41</i> (phylum <i>Acidobacteriota</i>) was one of two core bacterial genera, and its relative abundance was positively correlated with the activity of the S-mobilizing enzyme. Therefore, light grazing is recommended to reduce negative effects on the grassland soil microbiome and its activity, and the grazing season should be considered when evaluating such grazing effects.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 11","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142717579","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":"Quantifying the fractal complexity of nutrient transport channels in <i>Escherichia coli</i> biofilms under varying cell shape and growth environment.","authors":"Beatrice Bottura, Liam Rooney, Morgan Feeney, Paul A Hoskisson, Gail McConnell","doi":"10.1099/mic.0.001511","DOIUrl":"10.1099/mic.0.001511","url":null,"abstract":"<p><p>Recent mesoscopic characterization of nutrient-transporting channels in <i>Escherichia coli</i> has allowed the identification and measurement of individual channels in whole mature colony biofilms. However, their complexity under different physiological and environmental conditions remains unknown. Analysis of confocal micrographs of colony biofilms formed by cell shape mutants of <i>E. coli</i> shows that channels have high fractal complexity, regardless of cell phenotype or growth medium. In particular, colony biofilms formed by the mutant strain Δ<i>ompR</i>, which has a wide-cell phenotype, have a higher fractal dimension when grown on rich medium than when grown on minimal medium, with channel complexity affected by glucose and agar concentrations in the medium. Osmotic stress leads to a dramatic reduction in the Δ<i>ompR</i> cell size but has a limited effect on channel morphology. This work shows that fractal image analysis is a powerful tool to quantify the effect of phenotypic mutations and growth environment on the morphological complexity of internal <i>E. coli</i> biofilm structures. If applied to a wider range of mutant strains, this approach could help elucidate the genetic determinants of channel formation in <i>E. coli</i> colony biofilms.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 11","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11649193/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142584778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The PrfA regulon of <i>Listeria monocytogenes</i> is induced by growth in low-oxygen microaerophilic conditions.","authors":"Lamis A Alnakhli, Marie Goldrick, Elizabeth Lord, Ian S Roberts","doi":"10.1099/mic.0.001516","DOIUrl":"10.1099/mic.0.001516","url":null,"abstract":"<p><p><i>Listeria monocytogenes</i> is a food-borne pathogen that must adapt to several environments both inside and outside the host. One such environment is the microaerophilic conditions encountered in the host intestine proximal to the mucosal surface. The aim of this study was to investigate the expression of the PrfA regulon in response to microaerophilic growth conditions in the presence of either glucose or glycerol as a carbon source using four transcriptional (P<i>hly</i>, P<i>actA</i>, P<i>/prfA</i> and P<i>/plcA</i>) gene fusions. Further, RNAseq analysis was used to identify global changes in gene expression during growth in microaerophilic conditions. Following microaerophilic growth, there was a PrfA-dependent increase in transcription from the P<i>hly</i>, P<i>actA</i> and P<i>/plcA</i> promoters, indicating that microaerophilic growth induces the PrfA regulon regardless of the carbon source with increased expression of the PrfA, LLO and ActA proteins. A <i>sigB</i> mutation had no effect on the induction of the PrfA regulon under microaerophilic conditions when glucose was used as a carbon source. In contrast, when glycerol was the carbon source, a <i>sigB</i> mutation increased expression from the P<i>hly</i> and P<i>actA</i> promoters regardless of the level of oxygen. The RNAseq analysis showed that 273 genes were specifically regulated by microaerophilic conditions either up or down including the PrfA regulon virulence factors. Overall, these data indicated that <i>L. monocytogenes</i> PrfA regulon is highly responsive to the low-oxygen conditions likely to be encountered in the small intestine and that SigB has an input into the regulation of the PrfA regulon when glycerol is the sole carbon source.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"170 11","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11575702/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142669739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}