Microbial Cell最新文献

{"title":"Mechanisms underlying lactic acid tolerance and its influence on lactic acid production in <i>Saccharomyces cerevisiae</i>.","authors":"Arne Peetermans,&nbsp;María R Foulquié-Moreno,&nbsp;Johan M Thevelein","doi":"10.15698/mic2021.06.751","DOIUrl":"https://doi.org/10.15698/mic2021.06.751","url":null,"abstract":"<p><p>One of the major bottlenecks in lactic acid production using microbial fermentation is the detrimental influence lactic acid accumulation poses on the lactic acid producing cells. The accumulation of lactic acid results in many negative effects on the cell such as intracellular acidification, anion accumulation, membrane perturbation, disturbed amino acid trafficking, increased turgor pressure, ATP depletion, ROS accumulation, metabolic dysregulation and metal chelation. In this review, the manner in which <i>Saccharomyces cerevisiae</i> deals with these issues will be discussed extensively not only for lactic acid as a singular stress factor but also in combination with other stresses. In addition, different methods to improve lactic acid tolerance in <i>S. cerevisiae</i> using targeted and non-targeted engineering methods will be discussed.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8144909/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39035092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Means of intracellular communication: touching, kissing, fusing.","authors":"Anne Spang","doi":"10.15698/mic2021.05.747","DOIUrl":"https://doi.org/10.15698/mic2021.05.747","url":null,"abstract":"<p><p>Eukaryotic cells are complicated factories that need ensure productivity and functionality on the cellular level as well as being able to communicate with their environment. In order to do so cells developed intracellular communication systems. For a long time, research focused mainly on the secretory/biosynthetic and endocytic routes for communication, leaving the communication with other organelles apart. In the last decade, this view has changed dramatically and a more holistic view of intracellular communication is emerging. We are still at the tip of the iceberg, but a common theme of touching, kissing, fusing is emerging as general principles of communication.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8080899/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38976003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neuropathogenesis caused by <i>Trypanosoma brucei</i>, still an enigma to be unveiled.","authors":"Katherine Figarella","doi":"10.15698/mic2021.04.745","DOIUrl":"https://doi.org/10.15698/mic2021.04.745","url":null,"abstract":"<p><p><i>Trypanosoma brucei</i> is one of the protozoa parasites that can enter the brain and cause injury associated with toxic effects of parasite-derived molecules or with immune responses against infection. Other protozoa parasites with brain tropism include <i>Toxoplasma, Plasmodium, Amoeba</i>, and, eventually, other <i>Trypanosomatids</i> such as <i>T. cruzi</i> and <i>Leishmania</i>. Together, these parasites affect billions of people worldwide and are responsible for more than 500.000 deaths annually. Factors determining brain tropism, mechanisms of invasion as well as processes ongoing inside the brain are not well understood. But, they depend on the parasite involved. The pathogenesis caused by <i>T. brucei</i> initiates locally in the area of parasite inoculation, soon trypanosomes rich the blood, and the disease enters in the so-called early stage. The pathomechanisms in this phase have been described, even molecules used to combat the disease are effective during this period. Later, the disease evolves towards a late-stage, characterized by the presence of parasites in the central nervous system (CNS), the so-called meningo-encephalitic stage. This phase of the disease has not been sufficiently examined and remains a matter of investigation. Here, I stress the importance of delve into the study of the neuropathogenesis caused by <i>T. brucei</i>, which will enable the identification of pathways that may be targeted to overcome parasites that reached the CNS. Finally, I highlight the impact that the application of tools developed in the last years in the field of neuroscience will have on the study of neglected tropical diseases.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010903/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25559177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aeration mitigates endoplasmic reticulum stress in <i>Saccharomyces cerevisiae</i> even without mitochondrial respiration.","authors":"Huong Thi Phuong,&nbsp;Yuki Ishiwata-Kimata,&nbsp;Yuki Nishi,&nbsp;Norie Oguchi,&nbsp;Hiroshi Takagi,&nbsp;Yukio Kimata","doi":"10.15698/mic2021.04.746","DOIUrl":"https://doi.org/10.15698/mic2021.04.746","url":null,"abstract":"<p><p><i>Saccharomyces cerevisiae</i> is a facultative anaerobic organism that grows well under both aerobic and hypoxic conditions in media containing abundant fermentable nutrients such as glucose. In order to deeply understand the physiological dependence of <i>S. cerevisiae</i> on aeration, we checked endoplasmic reticulum (ER)-stress status by monitoring the splicing of <i>HAC1</i> mRNA, which is promoted by the ER stress-sensor protein, Ire1. <i>HAC1</i>-mRNA splicing that was caused by conventional ER-stressing agents, including low concentrations of dithiothreitol (DTT), was more potent in hypoxic cultures than in aerated cultures. Moreover, growth retardation was observed by adding low-dose DTT into hypoxic cultures of <i>ire1</i>Δ cells. Unexpectedly, aeration mitigated ER stress and DTT-induced impairment of ER oxidative protein folding even when mitochondrial respiration was halted by the ρ^o mutation. An ER-located protein Ero1 is known to directly consume molecular oxygen to initiate the ER protein oxidation cascade, which promotes oxidative protein folding of ER client proteins. Our further study using <i>ero1</i>-mutant strains suggested that, in addition to mitochondrial respiration, this Ero1-medaited reaction contributes to mitigation of ER stress by molecular oxygen. Taken together, here we demonstrate a scenario in which aeration acts beneficially on <i>S. cerevisiae</i> cells even under fermentative conditions.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010904/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25559178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Barcode sequencing and a high-throughput assay for chronological lifespan uncover ageing-associated genes in fission yeast","authors":"Catalina-Andreea Romila, StJohn Townsend, M. Malecki, S. Kamrad, María Rodríguez-López, Olivia Hillson, Cristina Cotobal, M. Ralser, J. Bähler","doi":"10.1101/2021.03.04.433786","DOIUrl":"https://doi.org/10.1101/2021.03.04.433786","url":null,"abstract":"Ageing-related processes are largely conserved, with simple organisms remaining the main platform to discover and dissect new ageing-associated genes. Yeasts provide potent model systems to study cellular ageing owing their amenability to systematic functional assays under controlled conditions. Even with yeast cells, however, ageing assays can be laborious and resource-intensive. Here we present improved experimental and computational methods to study chronological lifespan in Schizosaccharomyces pombe. We decoded the barcodes for 3206 mutants of the latest gene-deletion library, enabling the parallel profiling of ∼700 additional mutants compared to previous screens. We then applied a refined method of barcode sequencing (Bar-seq), addressing technical and statistical issues raised by persisting DNA in dead cells and sampling bottlenecks in aged cultures, to screen for mutants showing altered lifespan during stationary phase. This screen identified 341 long-lived mutants and 1246 short-lived mutants which point to many previously unknown ageing-associated genes, including 51 conserved but entirely uncharacterized genes. The ageing-associated genes showed coherent enrichments in processes also associated with human ageing, particularly with respect to ageing in non-proliferative brain cells. We also developed an automated colony-forming unit assay for chronological lifespan to facilitate medium- to high-throughput ageing studies by saving time and resources compared to the traditional assay. Results from the Bar-seq screen showed good agreement with this new assay, validating 33 genes not previously associated with cellular ageing. This study provides an effective methodological platform and identifies many new ageing-associated genes as a framework for analysing cellular ageing in yeast and beyond.","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47081069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lichens - growing greenhouses <i>en miniature</i>.","authors":"Martin Grube","doi":"10.15698/mic2021.03.743","DOIUrl":"https://doi.org/10.15698/mic2021.03.743","url":null,"abstract":"Beards hanging from trees and colorful patches encrusting rocks are silent success stories of lichens, the fascinating life styles fungi can form with algae (Fig. 1). Lichens were show-cases to introduce the concept of symbiosis (as ‘Symbiotismus’ [1]). The self-support of symbiotic life styles is recognized as gear-shift of evolution and applied to a vast number of examples where continued interactions between species lead to metabolic or phenotypic novelty. Lichen symbioses are still outstanding for the structural longevity and occurrence in environments, some which are unsuitable for most other organisms. Lichens often form major components Arctic tundra, boreal forest floors, but also on lava fields, rock surfaces along coasts or in extremely high altitudes. The perseverance of lichens in such hostile places appears to be in striking contrast to observed ecological specialization and their lack in urban and trafficated places. The symbiosis is indeed very sensitive during physiologically active state but the puzzle of extremotolerance is solved when we consider poikilohydry: because lichens hardly possess structural or functional mechanisms to maintain and/or regulate water content, desiccation rapidly causes shut down of metabolism. Yet, in contrast to many other life forms, lichens cope extremely well with recurrent changes of water availability. Lichens have an outstanding ability to revitalize from dry stages. Lichens can endure extreme desiccation to water contents (below 0.1 g H2O g–1 dry weight (DW)), which causes ‘vitrification’, the transition of their cytoplasm to a ‘glassy’ state and cease of metabolism. To find out what reactions may occur at different levels of desiccation in lichens, Candotto Carniel et al. [2] used dynamic mechanical thermal analysis as for assessment of molecular mobility, while deand re-epoxidation of the xanthophyll cycle pigments served as a proxy to assess enzyme activity. At 20°C vitrification occurred between 0.12–0.08 g H2O g−1 DW and enzymes were active in a ‘rubbery’ state (0.17 g H2O g−1 DW) but not in a glassy state (0.03 g H2O g−1 DW). Therefore, desiccated tissues may appear to be ‘dry’ in the conventional sense, but subtle differences in water content will have substantial consequences on the types of (bio)chemical reactions that can occur, with downstream effects on longevity in the desiccated state. Lichen thalli must be flexible to retain shape integrity under poikilohydric conditions, which involve shrinking and swelling of the symbiotic structures. The photosynthetic partners in the majority of lichens, algae or cyanobacteria, are typically sheltered beneath coherent peripheral layers formed by fungal cells, which are tightly glued together in a common extracellular matrix by their gelatinizing outer cell walls. Spribille et al. [3] compiled current knowledge about the composition of involved polysaccharides and emphasized the important role of acidic polysaccharides in holding lichens toget","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7919387/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25454214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"When the pandemic opts for the lockdown: Secretion system evolution in the cholera bacterium.","authors":"Francis J Santoriello,&nbsp;Stefan Pukatzki","doi":"10.15698/mic2021.03.744","DOIUrl":"https://doi.org/10.15698/mic2021.03.744","url":null,"abstract":"<p><p><i>Vibrio cholerae</i>, the causative agent of the diarrheal disease cholera, is a microbe capable of inhabiting two different ecosystems: chitinous surfaces in brackish, estuarine waters and the epithelial lining of the human gastrointestinal tract. <i>V. cholerae</i> defends against competitive microorganisms with a contact-dependent, contractile killing machine called the type VI secretion system (T6SS) in each of these niches. The T6SS resembles an inverted T4 bacteriophage tail and is used to deliver toxic effector proteins into neighboring cells. Pandemic strains of <i>V. cholerae</i> encode a unique set of T6SS effector proteins, which may play a role in pathogenesis or pandemic spread. In our recent study (Santoriello <i>et al.</i> (2020), Nat Commun, doi: 10.1038/s41467-020-20012-7), using genomic and molecular biology tools, we demonstrated that the T6SS island Auxiliary Cluster 3 (Aux3) is unique to pandemic strains of <i>V. cholerae</i>. We went on to show that Aux3 is related to a phage-like element circulating in environmental <i>V. cholerae</i> strains and that two genetic domestication events formed the pandemic Aux3 cluster during the evolution of the pandemic clone. Our findings support two main conclusions: (1) Aux3 evolution from phage-like element to T6SS cluster offers a snapshot of phage domestication in early T6SS evolution and (2) chromosomal maintenance of Aux3 was advantageous to the common ancestor of <i>V. cholerae</i> pandemic strains.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7919388/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25454215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biofilms by bacterial human pathogens: Clinical relevance - development, composition and regulation - therapeutical strategies.","authors":"Adina Schulze, Fabian Mitterer, Joao P Pombo, Stefan Schild","doi":"10.15698/mic2021.02.741","DOIUrl":"10.15698/mic2021.02.741","url":null,"abstract":"<p><p>Notably, bacterial biofilm formation is increasingly recognized as a passive virulence factor facilitating many infectious disease processes. In this review we will focus on bacterial biofilms formed by human pathogens and highlight their relevance for diverse diseases. Along biofilm composition and regulation emphasis is laid on the intensively studied biofilms of <i>Vibrio cholerae, Pseudomonas aeruginosa</i> and <i>Staphylococcus spp.</i>, which are commonly used as biofilm model organisms and therefore contribute to our general understanding of bacterial biofilm (patho-)physiology. Finally, therapeutical intervention strategies targeting biofilms will be discussed.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7841849/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25342354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel BR-SMAD is required for larval development in barber's pole worm <i>Haemonchus contortus</i>.","authors":"Fangfang Li,&nbsp;Peixi Qin,&nbsp;Lisha Ye,&nbsp;Nishith Gupta,&nbsp;Min Hu","doi":"10.15698/mic2021.02.742","DOIUrl":"https://doi.org/10.15698/mic2021.02.742","url":null,"abstract":"<p><p>SMAD proteins mediate TGF-β signaling and thereby regulate the metazoan development; however, they are poorly defined in <i>Haemonchus contortus</i>-a common blood-sucking parasitic nematode of small ruminants. Here, we characterized an R-SMAD family protein in <i>H. contortus</i> termed <i>Hc</i>SMA2, which is closely related to <i>Caenorhabditis elegans</i> SMA2 (<i>Ce</i>SMA2) involved in the bone morphogenetic protein (BMP) signaling. <i>Hcsma2</i> is transcribed in all developmental stages of <i>H. contortus</i> but highly induced in the adult male worms. The RNA interference with <i>Hcsma2</i> retarded the transition of infective L3 into L4 larvae. Besides, the bimolecular fluorescence complementation revealed the interaction of <i>Hc</i>SMA2 with a TGF-β-activated-R-SMAD (<i>Hc</i>DAF8). Together these results show a BMP-like receptor-regulated SMAD in <i>H. contortus</i> that is required for larval differentiation and underscore an adaptive functional repurposing of BMP-signaling in parasitic worms.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2020-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7841850/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25342912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maintaining phagosome integrity during fungal infection: do or die?","authors":"Mabel Yang,&nbsp;Glenn F W Walpole,&nbsp;Johannes Westman","doi":"10.15698/mic2020.12.738","DOIUrl":"https://doi.org/10.15698/mic2020.12.738","url":null,"abstract":"<p><p>Professional phagocytes represent a critical node in innate immunity and tissue homeostasis through their specialized ability to eat, drink, and digest material from the extracellular milieu. The degradative and microbicidal functions of phagocytes rely on the fusion of lysosomes with endosomal compartments such as phagosomes, resulting in the digestion and recycling of internalized prey and debris. Despite these efforts, several particularly dangerous infections result from a class of tenacious pathogens that resist digestion, often surviving and even proliferating within the confines of the phagosomal membrane. One such example, <i>Candida albicans,</i> is a commensal polymorphic fungus that colonizes ~50% of the population and can cause life-threatening infections in immunocompromised patients. Not only can <i>C. albicans</i> survive within phagosomes, but its ingestion by macropahges triggers a yeast-to-hyphal transition promoting rapid intraphagosomal growth (several microns per hour) while imposing a substantial mechanical burden on the phagosomal membrane surrounding the fungus. Preservation of membrane integrity is essential to maintain the hostile internal environment of the phagosome, a functionality of degradative enzymes and oxidative stress. Yet, biological membranes such as phagosomes have a limited capacity to stretch. Using <i>C. albicans</i> as a model intracellular pathogen, our recent work reveals a mechanism by which phagosomes respond to intraphagosomal growth of pathogens by expanding their surface area, and as a result, maintain the integrity of the phagosomal membrane. We hypothesized that this expansion would be facilitated by the delivery and fusion of membrane from extraneous sources with the phagosome. Consistently, macrophages respond to the yeast-to-hyphal transition through a stretch-induced release of phagosomal calcium, leading to recruitment and insertion of lysosomes that accommodate the expansion of the phagolysosome and preserve its integrity. Below, we discuss this calcium-dependent mechanism of lysosome insertion as a means of avoiding phagosomal rupture. Further, we examine the implications of membrane integrity on the delicate balance between the host and pathogen by focusing on fungal stress responses, nutrient acquisition, inflammasome activation, and cell death.</p>","PeriodicalId":18397,"journal":{"name":"Microbial Cell","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2020-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7713255/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38387172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}