Microbial Physiology最新文献

{"title":"Polyhydroxybutyrate: A Useful Product of Chlorotic Cyanobacteria.","authors":"Moritz Koch,&nbsp;Karl Forchhammer","doi":"10.1159/000515617","DOIUrl":"https://doi.org/10.1159/000515617","url":null,"abstract":"<p><p>Polyhydroxybutyrate (PHB) is a carbon polymer with diverse functions, varying greatly on the organism producing it. This microreview describes the current knowledge about PHB metabolism, structure, and different physiological roles with a special focus on cyanobacteria. Despite the physiological function of PHB in the cyanobacterial phylum still being unknown, these organisms provide the unique opportunity to directly convert atmospheric CO2 into bioplastic using a solar-based process. Recent research on PHB metabolism in the cyanobacterial model organism Synechocystis revealed a sophisticated control of PHB granule formation. Novel insights about the metabolic background of PHB synthesis resulted in the engineering of the first cyanobacterial superproducer strain.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 2","pages":"67-77"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000515617","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38904779","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 Multiple Roles of Polyphosphate in Ralstonia eutropha and Other Bacteria.","authors":"Hanna Rosigkeit,&nbsp;Lea Kneißle,&nbsp;Stanislav Obruča,&nbsp;Dieter Jendrossek","doi":"10.1159/000515741","DOIUrl":"https://doi.org/10.1159/000515741","url":null,"abstract":"<p><p>An astonishing variety of functions has been attributed to polyphosphate (polyP) in prokaryotes. Besides being a reservoir of phosphorus, functions in exopolysaccharide formation, motility, virulence and in surviving various forms of stresses such as exposure to heat, extreme pH, oxidative agents, high osmolarity, heavy metals and others have been ascribed to polyP. In this contribution, we will provide a historical overview on polyP, will then describe the key proteins of polyP synthesis, the polyP kinases, before we will critically assess of the underlying data on the multiple functions of polyP and provide evidence that - with the exception of a P-storage-function - most other functions of polyP are not relevant for survival of Ralstonia eutropha, a biotechnologically important beta-proteobacterial species.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 2","pages":"163-177"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000515741","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39015267","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 Formation of Spore-Like Akinetes: A Survival Strategy of Filamentous Cyanobacteria.","authors":"Ritu Garg,&nbsp;Iris Maldener","doi":"10.1159/000517443","DOIUrl":"https://doi.org/10.1159/000517443","url":null,"abstract":"<p><p>Some cyanobacteria of the order Nostocales can form akinetes, spore-like dormant cells resistant to various unfavorable environmental fluctuations. Akinetes are larger than vegetative cells and contain large quantities of reserve products, mainly glycogen and the nitrogen storage polypeptide polymer cyanophycin. Akinetes are enveloped in a thick protective coat containing a multilayered structure and are able to germinate into new vegetative cells under suitable growth conditions. Here, we summarize the significant morphological and physiological changes that occur during akinete differentiation and germination and present our investigation of the physiological function of the storage polymer cyanophycin in these cellular processes. We show that the cyanophycin production is not required for formation and germination of the akinetes in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 3","pages":"296-305"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39383637","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":"Amyloid Proteins in Plant-Associated Microbial Communities.","authors":"Daniel Gómez-Pérez,&nbsp;Vasvi Chaudhry,&nbsp;Ariane Kemen,&nbsp;Eric Kemen","doi":"10.1159/000516014","DOIUrl":"https://doi.org/10.1159/000516014","url":null,"abstract":"<p><p>Amyloids have proven to be a widespread phenomenon rather than an exception. Many proteins presenting the hallmarks of this characteristic beta sheet-rich folding have been described to date. Particularly common are functional amyloids that play an important role in the promotion of survival and pathogenicity in prokaryotes. Here, we describe important developments in amyloid protein research that relate to microbe-microbe and microbe-host interactions in the plant microbiome. Starting with biofilms, which are a broad strategy for bacterial persistence that is extremely important for plant colonization. Microbes rely on amyloid-based mechanisms to adhere and create a protective coating that shelters them from external stresses and promotes cooperation. Another strategy generally carried out by amyloids is the formation of hydrophobic surface layers. Known as hydrophobins, these proteins coat the aerial hyphae and spores of plant pathogenic fungi, as well as certain bacterial biofilms. They contribute to plant virulence through promoting dissemination and infectivity. Furthermore, antimicrobial activity is an interesting outcome of the amyloid structure that has potential application in medicine and agriculture. There are many known antimicrobial amyloids released by animals and plants; however, those produced by bacteria or fungi remain still largely unknown. Finally, we discuss amyloid proteins with a more indirect mode of action in their host interactions. These include virulence-promoting harpins, signaling transduction that functions through amyloid templating, and root nodule bacteria proteins that promote plant-microbe symbiosis. In summary, amyloids are an interesting paradigm for their many functional mechanisms linked to bacterial survival in plant-associated microbial communities.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 2","pages":"88-98"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000516014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39078761","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":"A Novel Enrichment Culture Highlights Core Features of Microbial Networks Contributing to Autotrophic Fe(II) Oxidation Coupled to Nitrate Reduction.","authors":"Yu-Ming Huang,&nbsp;Daniel Straub,&nbsp;Andreas Kappler,&nbsp;Nicole Smith,&nbsp;Nia Blackwell,&nbsp;Sara Kleindienst","doi":"10.1159/000517083","DOIUrl":"https://doi.org/10.1159/000517083","url":null,"abstract":"<p><p>Fe(II) oxidation coupled to nitrate reduction (NRFO) has been described for many environments. Yet very few autotrophic microorganisms catalysing NRFO have been cultivated and their diversity, as well as their mechanisms for NRFO in situ remain unclear. A novel autotrophic NRFO enrichment culture, named culture BP, was obtained from freshwater sediment. After more than 20 transfers, culture BP oxidized 8.22 mM of Fe(II) and reduced 2.42 mM of nitrate within 6.5 days under autotrophic conditions. We applied metagenomic, metatranscriptomic, and metaproteomic analyses to culture BP to identify the microorganisms involved in autotrophic NRFO and to unravel their metabolism. Overall, twelve metagenome-assembled genomes (MAGs) were constructed, including a dominant Gallionellaceae sp. MAG (≥71% relative abundance). Genes and transcripts associated with potential Fe(II) oxidizers in culture BP, identified as a Gallionellaceae sp., Noviherbaspirillum sp., and Thiobacillus sp., were likely involved in metal oxidation (e.g., cyc2, mtoA), denitrification (e.g., nirK/S, norBC), carbon fixation (e.g., rbcL), and oxidative phosphorylation. The putative Fe(II)-oxidizing protein Cyc2 was detected for the Gallionellaceae sp. Overall, a complex network of microbial interactions among several Fe(II) oxidizers and denitrifiers was deciphered in culture BP that might resemble NRFO mechanisms in situ. Furthermore, 16S rRNA gene amplicon sequencing from environmental samples revealed 36 distinct Gallionellaceae taxa, including the key player of NRFO from culture BP (approx. 0.13% relative abundance in situ). Since several of these in situ-detected Gallionellaceae taxa were closely related to the key player in culture BP, this suggests that the diversity of organisms contributing to NRFO might be higher than currently known.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 3","pages":"280-295"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000517083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39066741","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":"Recovery of Unicellular Cyanobacteria from Nitrogen Chlorosis: A Model for Resuscitation of Dormant Bacteria.","authors":"Niels Neumann,&nbsp;Sofia Doello,&nbsp;Karl Forchhammer","doi":"10.1159/000515742","DOIUrl":"https://doi.org/10.1159/000515742","url":null,"abstract":"<p><p>Nitrogen starvation induces developmental transitions in cyanobacteria. Whereas complex multicellular cyanobacteria of the order Nostocales can differentiate specialized cells that perform nitrogen fixation in the presence of oxygenic photosynthesis, non-diazotrophic unicellular strains, such as Synechococcus elongatus or Synechocystis PCC 6803, undergo a transition into a dormant non-growing state. Due to loss of pigments during this acclimation, the process is termed chlorosis. Cells maintain viability in this state for prolonged periods of time, until they encounter a useable nitrogen source, which triggers a highly coordinated awakening process, termed resuscitation. The minimal set of cellular activity that maintains the viability of cells during chlorosis and ensures efficient resuscitation represents the organism's equivalent of the BIOS, the basic input/output system of a computer, that helps \"booting\" the operation system after switching on. This review summarizes the recent research in the resuscitation of cyanobacteria, representing a powerful model for the awakening of dormant bacteria.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 2","pages":"78-87"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000515742","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38893272","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":"Diversity in Starvation Survival Strategies and Outcomes among Heterotrophic Proteobacteria.","authors":"Megan Bergkessel,&nbsp;Laurent Delavaine","doi":"10.1159/000516215","DOIUrl":"https://doi.org/10.1159/000516215","url":null,"abstract":"<p><p>Heterotrophic Proteobacteria are versatile opportunists that have been extensively studied as model organisms in the laboratory, as both pathogens and beneficial symbionts of plants and animals, and as ubiquitous organisms found free-living in many environments. Succeeding in these niches requires an ability to persist for potentially long periods of time in growth-arrested states when essential nutrients become limiting. The tendency of these bacteria to grow in dense biofilm communities frequently leads to the development of steep nutrient gradients and deprivation of interior cells even when the environment is nutrient rich. Surviving within host environments also likely requires tolerating growth arrest due to the host limiting access to nutrients and transitioning between hosts may require a period of survival in a nutrient-poor environment. Interventions to maximise plant-beneficial activities and minimise infections by bacteria will require a better understanding of metabolic and regulatory networks that contribute to starvation survival, and how these networks function in diverse organisms. Here we focus on carbon starvation as a growth-arresting condition that limits availability not only of substrates for biosynthesis but also of energy for ongoing maintenance of the electrochemical gradient across the cell envelope and cellular integrity. We first review models for studying bacterial starvation and known strategies that contribute to starvation survival. We then present the results of a survey of carbon starvation survival strategies and outcomes in ten bacterial strains, including representatives from the orders Enterobacterales and Pseudomonadales (both Gammaproteobacteria) and Burkholderiales (Betaproteobacteria). Finally, we examine differences in gene content between the highest and lowest survivors to identify metabolic and regulatory adaptations that may contribute to differences in starvation survival.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 2","pages":"146-162"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000516215","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38968322","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":"Poly- and Monoamine Metabolism in Streptomyces coelicolor: The New Role of Glutamine Synthetase-Like Enzymes in the Survival under Environmental Stress.","authors":"Sergii Krysenko,&nbsp;Arne Matthews,&nbsp;Tobias Busche,&nbsp;Agnieszka Bera,&nbsp;Wolfgang Wohlleben","doi":"10.1159/000516644","DOIUrl":"https://doi.org/10.1159/000516644","url":null,"abstract":"<p><p>Soil bacteria from the genus Streptomyces, phylum Actinobacteria, feature a complex metabolism and diverse adaptations to environmental stress. These characteristics are consequences of variable nutrition availability in the soil and allow survival under changing nitrogen conditions. Streptomyces coelicolor is a model organism for Actinobacteria and is able to use nitrogen from a variety of sources including unusual compounds originating from the decomposition of dead plant and animal material, such as polyamines or monoamines (like ethanolamine). Assimilation of nitrogen from these sources in S. coelicolor remains largely unstudied. Using microbiological, biochemical and in silico approaches, it was recently possible to postulate polyamine and monoamine (ethanolamine) utilization pathways in S. coelicolor. Glutamine synthetase-like enzymes (GS-like) play a central role in these pathways. Extensive studies have revealed that these enzymes are able to detoxify polyamines or monoamines and allow the survival of S. coelicolor in soil containing an excess of these compounds. On the other hand, at low concentrations, polyamines and monoamines can be utilized as nitrogen and carbon sources. It has been demonstrated that the first step in poly-/monoamine assimilation is catalyzed by GlnA3 (a γ-glutamylpolyamine synthetase) and GlnA4 (a γ-glutamylethanolamide synthetase), respectively. First insights into the regulation of polyamine and ethanolamine metabolism have revealed that the expression of the glnA3 and the glnA4 gene are controlled on the transcriptional level.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 3","pages":"233-247"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000516644","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39039388","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":"Contribution of the Clp Protease to Bacterial Survival and Mitochondrial Homoeostasis.","authors":"Astrid Illigmann,&nbsp;Yvonne Thoma,&nbsp;Stefan Pan,&nbsp;Laura Reinhardt,&nbsp;Heike Brötz-Oesterhelt","doi":"10.1159/000517718","DOIUrl":"https://doi.org/10.1159/000517718","url":null,"abstract":"<p><p>Fast adaptation to environmental changes ensures bacterial survival, and proteolysis represents a key cellular process in adaptation. The Clp protease system is a multi-component machinery responsible for protein homoeostasis, protein quality control, and targeted proteolysis of transcriptional regulators in prokaryotic cells and prokaryote-derived organelles of eukaryotic cells. A functional Clp protease complex consists of the tetradecameric proteolytic core ClpP and a hexameric ATP-consuming Clp-ATPase, several of which can associate with the same proteolytic core. Clp-ATPases confer substrate specificity by recognising specific degradation tags, and further selectivity is conferred by adaptor proteins, together allowing for a fine-tuned degradation process embedded in elaborate regulatory networks. This review focuses on the contribution of the Clp protease system to prokaryotic survival and summarises the current state of knowledge for exemplary bacteria in an increasing degree of interaction with eukaryotic cells. Starting from free-living bacteria as exemplified by a non-pathogenic and a pathogenic member of the Firmicutes, i.e., Bacillus subtilis and Staphylococcus aureus, respectively, we turn our attention to facultative and obligate intracellular bacterial pathogens, i.e., Mycobacterium tuberculosis, Listeria monocytogenes, and Chlamydia trachomatis, and conclude with mitochondria. Under stress conditions, the Clp protease system exerts its pivotal role in the degradation of damaged proteins and controls the timing and extent of the heat-shock response by regulatory proteolysis. Key regulators of developmental programmes like natural competence, motility, and sporulation are also under Clp proteolytic control. In many pathogenic species, the Clp system is required for the expression of virulence factors and essential for colonising the host. In accordance with its evolutionary origin, the human mitochondrial Clp protease strongly resembles its bacterial counterparts, taking a central role in protein quality control and homoeostasis, energy metabolism, and apoptosis in eukaryotic cells, and several cancer cell types depend on it for proliferation.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 3","pages":"260-279"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39347578","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":"Analysis of Kytococcus sedentarius Strain Isolated from a Dehumidifier Operating in a University Lecture Theatre: Systems for Aerobic Respiration, Resisting Osmotic Stress, and Sensing Nitric Oxide.","authors":"Meshari Ahmed Alhadlaq,&nbsp;Jeffrey Green,&nbsp;Bassam K Kudhair","doi":"10.1159/000512751","DOIUrl":"https://doi.org/10.1159/000512751","url":null,"abstract":"<p><p>A strain of Kytococcus sedentarius was isolated from a dehumidifier operating in a university lecture theatre. Genome analysis and phenotypic characterisation showed that this strain, K. sedentarius MBB13, was a moderately halotolerant aerobe with a branched aerobic electron transport chain and genes that could contribute to erythromycin resistance. The major compatible solute was glycine betaine, with ectoine and proline being deployed at higher osmolarities. Actinobacteria possess multiple WhiB-like (Wbl) regulatory proteins, and K. sedentarius MBB13 has four (WhiB1, WhiB2, WhiB3, and WhiB7). Wbls are iron-sulfur proteins that regulate gene expression through interactions with RNA polymerase sigma factors and/or other regulatory proteins. Bacterial two-hybrid analyses suggested that WhiB1 and WhiB2, but not WhiB3 and WhiB7, interact with the C-terminal domain of the major sigma factor, σA; no interaction was detected between any of the Wbl proteins and the only alternative sigma factors, σB, σH, or σJ. The interaction between σA and WhiB1 or WhiB2 was disrupted in a heterologous system under growth conditions that produce nitric oxide and the iron-sulfur clusters of the isolated WhiB1 and WhiB2 proteins reacted with nitric oxide. Thus, K. sedentarius strain exhibits the major phenotypic characteristics of the type strain and a comprehensive examination of the interactions between its four Wbl proteins and four sigma factors suggested that the Wbl proteins all operate through interaction with σA.</p>","PeriodicalId":18457,"journal":{"name":"Microbial Physiology","volume":"31 2","pages":"135-145"},"PeriodicalIF":3.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000512751","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25487960","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}