Bacterial Persisters and Infection: Past, Present, and Progressing.
Abstract Persisters are nongrowing, transiently antibiotic-tolerant bacteria within a clonal population of otherwise susceptible cells. Their formation is triggered by environmental cues and involves the main bacterial stress response pathways that allow persisters to survive many harsh conditions, including antibiotic exposure. During infection, bacterial pathogens are exposed to a vast array of stresses in the host and form nongrowing persisters that survive both antibiotics and host immune responses, thereby most likely contributing to the relapse of many infections. While antibiotic persisters have been extens...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Gollan B, Grabe G, Michaux C, Helaine S Tags: Annu Rev Microbiol Source Type: research

Introduction: Remembering Olaf Schneewind.
PMID: 31500533 [PubMed - in process] (Source: Annual Review of Microbiology)
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Gottesman S Tags: Annu Rev Microbiol Source Type: research

The Way It Was.
Abstract Mary Osborn was a native Californian. She was an undergraduate at the University of California, Berkeley, where she worked in the laboratory of I.L. Chaikoff. She received her PhD at the University of Washington, where her work on the role of folic acid coenzymes in one-carbon metabolism revealed the mechanism of action of methotrexate. After postdoctoral training with Bernard Horecker in the Department of Microbiology at New York University (NYU), she embarked on her research career as a faculty member in the NYU Department of Microbiology and in the Department of Molecular Biology at Albert Einstein Col...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Osborn MJ Tags: Annu Rev Microbiol Source Type: research

Diversity, Genomics, and Distribution of Phytoplankton-Cyanobacterium Single-Cell Symbiotic Associations.
Abstract Cyanobacteria are common in symbiotic relationships with diverse multicellular organisms (animals, plants, fungi) in terrestrial environments and with single-celled heterotrophic, mixotrophic, and autotrophic protists in aquatic environments. In the sunlit zones of aquatic environments, diverse cyanobacterial symbioses exist with autotrophic taxa in phytoplankton, including dinoflagellates, diatoms, and haptophytes (prymnesiophytes). Phototrophic unicellular cyanobacteria related to Synechococcus and Prochlorococcus are associated with a number of groups. N2-fixing cyanobacteria are symbiotic with diatoms...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Foster RA, Zehr JP Tags: Annu Rev Microbiol Source Type: research

Multiple Roles of c-di-GMP Signaling in Bacterial Pathogenesis.
Abstract The intracellular signaling molecule cyclic di-GMP (c-di-GMP) regulates the lifestyle of bacteria and controls many key functions and mechanisms. In the case of bacterial pathogens, a wide variety of virulence lifestyle factors have been shown to be regulated by c-di-GMP. Evidence of the importance of this molecule for bacterial pathogenesis has become so great that new antimicrobial agents are tested for their capacity of targeting c-di-GMP signaling. This review summarizes the current knowledge on this topic and reveals its application for the development of new antivirulence intervention strategies. ...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Valentini M, Filloux A Tags: Annu Rev Microbiol Source Type: research

Coordination of the Cell Cycle in Trypanosomes.
Abstract Trypanosomes have complex life cycles within which there are both proliferative and differentiation cell divisions. The coordination of the cell cycle to achieve these different divisions is critical for the parasite to infect both host and vector. From studying the regulation of the proliferative cell cycle of the Trypanosoma brucei procyclic life cycle stage, three subcycles emerge that control the duplication and segregation of (a) the nucleus, (b) the kinetoplast, and (c) a set of cytoskeletal structures. We discuss how the clear dependency relationships within these subcycles, and the potential for c...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Wheeler RJ, Gull K, Sunter JD Tags: Annu Rev Microbiol Source Type: research

Chromatic Acclimation in Cyanobacteria: A Diverse and Widespread Process for Optimizing Photosynthesis.
Abstract Chromatic acclimation (CA) encompasses a diverse set of molecular processes that involve the ability of cyanobacterial cells to sense ambient light colors and use this information to optimize photosynthetic light harvesting. The six known types of CA, which we propose naming CA1 through CA6, use a range of molecular mechanisms that likely evolved independently in distantly related lineages of the Cyanobacteria phylum. Together, these processes sense and respond to the majority of the photosynthetically relevant solar spectrum, suggesting that CA provides fitness advantages across a broad range of light co...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Sanfilippo JE, Garczarek L, Partensky F, Kehoe DM Tags: Annu Rev Microbiol Source Type: research

Signaling Cascades Governing Entry into and Exit from Host Cells by Toxoplasma gondii.
Abstract The Apicomplexa phylum includes a large group of obligate intracellular protozoan parasites responsible for important diseases in humans and animals. Toxoplasma gondii is a widespread parasite with considerable versatility, and it is capable of infecting virtually any warm-blooded animal, including humans. This outstanding success can be attributed at least in part to an efficient and continuous sensing of the environment, with a ready-to-adapt strategy. This review updates the current understanding of the signals governing the lytic cycle of T. gondii, with particular focus on egress from infected cells,...
Source: Annual Review of Microbiology - September 8, 2019 Category: Microbiology Authors: Bisio H, Soldati-Favre D Tags: Annu Rev Microbiol Source Type: research

Paleomicrobiology: Diagnosis and Evolution of Ancient Pathogens.
Krause J Abstract The last century has witnessed progress in the study of ancient infectious disease from purely medical descriptions of past ailments to dynamic interpretations of past population health that draw upon multiple perspectives. The recent adoption of high-throughput DNA sequencing has led to an expanded understanding of pathogen presence, evolution, and ecology across the globe. This genomic revolution has led to the identification of disease-causing microbes in both expected and unexpected contexts, while also providing for the genomic characterization of ancient pathogens previously believed to be...
Source: Annual Review of Microbiology - July 5, 2019 Category: Microbiology Authors: Bos KI, Kühnert D, Herbig A, Esquivel-Gomez LR, Valtueña AA, Barquera R, Giffin K, Kumar Lankapalli A, Nelson EA, Sabin S, Spyrou MA, Krause J Tags: Annu Rev Microbiol Source Type: research

The Metabolic Basis of Pathogenesis and Host Adaptation in Rice Blast.
Abstract The blast disease, caused by the ascomycete Magnaporthe oryzae, poses a great threat to rice production worldwide. Increasing use of fungicides and/or blast-resistant varieties of rice (Oryza sativa) has proved to be ineffective in long-term control of blast disease under field conditions. To develop effective and durable resistance to blast, it is important to understand the cellular mechanisms underlying pathogenic development in M. oryzae. In this review, we summarize the latest research in phototropism, autophagy, nutrient and redox signaling, and intrinsic phytohormone mimics in M. oryzae for cellula...
Source: Annual Review of Microbiology - July 5, 2019 Category: Microbiology Authors: Deng YZ, Naqvi NI Tags: Annu Rev Microbiol Source Type: research

Assembly and Subcellular Localization of Bacterial Type VI Secretion Systems.
Abstract Bacteria need to deliver large molecules out of the cytosol to the extracellular space or even across membranes of neighboring cells to influence their environment, prevent predation, defeat competitors, or communicate. A variety of protein-secretion systems have evolved to make this process highly regulated and efficient. The type VI secretion system (T6SS) is one of the largest dynamic assemblies in gram-negative bacteria and allows for delivery of toxins into both bacterial and eukaryotic cells. The recent progress in structural biology and live-cell imaging shows the T6SS as a long contractile sheath ...
Source: Annual Review of Microbiology - June 21, 2019 Category: Microbiology Authors: Wang J, Brodmann M, Basler M Tags: Annu Rev Microbiol Source Type: research

Human Coronavirus: Host-Pathogen Interaction.
Abstract Human coronavirus (HCoV) infection causes respiratory diseases with mild to severe outcomes. In the last 15 years, we have witnessed the emergence of two zoonotic, highly pathogenic HCoVs: severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). Replication of HCoV is regulated by a diversity of host factors and induces drastic alterations in cellular structure and physiology. Activation of critical signaling pathways during HCoV infection modulates the induction of antiviral immune response and contributes to the pathogenesis of HCoV. Recent st...
Source: Annual Review of Microbiology - June 21, 2019 Category: Microbiology Authors: Fung TS, Liu DX Tags: Annu Rev Microbiol Source Type: research

Small Is Mighty-Chemical Communication Systems in Pseudomonas Aeruginosa.
Abstract Pseudomonas aeruginosa is an opportunistic pathogen that causes a variety of acute and chronic infections. Usually a commensal on the host body, P. aeruginosa is capable of transforming into a virulent pathogen upon sensing favorable changes in the host immune system or stress cues. P. aeruginosa infections are hard to eradicate, because this pathogen has developed strong resistance to most conventional antibiotics; in addition, in chronic infections it commonly forms a biofilm matrix, which provides bacterial cells a protected environment to withstand various stresses including antibiotics. Given its imp...
Source: Annual Review of Microbiology - June 21, 2019 Category: Microbiology Authors: Dela Ahator S, Zhang L Tags: Annu Rev Microbiol Source Type: research

Defense and Counterdefense During Plant-Pathogenic Oomycete Infection.
Abstract Plant pathogenic oomycetes include numerous species that are ongoing threats to agriculture and natural ecosystems. Understanding the molecular dialogs between oomycetes and plants is instrumental for sustaining effective disease control. Plants respond to oomycete infection by multiple defense actions including strengthening of physical barriers, production of antimicrobial molecules, and programmed cell death. These responses are tightly controlled and integrated via a three-layered immune system consisting of a multiplex recognition layer, a resilient signal-integration layer, and a diverse defense-act...
Source: Annual Review of Microbiology - June 21, 2019 Category: Microbiology Authors: Wang Y, Tyler BM, Wang Y Tags: Annu Rev Microbiol Source Type: research

Two-Component Sensing and Regulation: How Do Histidine Kinases Talk with Response Regulators at the Molecular Level?
Abstract Perceiving environmental and internal information and reacting in adaptive ways are essential attributes of living organisms. Two-component systems are relevant protein machineries from prokaryotes and lower eukaryotes that enable cells to sense and process signals. Implicating sensory histidine kinases and response regulator proteins, both components take advantage of protein phosphorylation and flexibility to switch conformations in a signal-dependent way. Dozens of two-component systems act simultaneously in any given cell, challenging our understanding about the means that ensure proper connectivity. ...
Source: Annual Review of Microbiology - June 21, 2019 Category: Microbiology Authors: Buschiazzo A, Trajtenberg F Tags: Annu Rev Microbiol Source Type: research

Bent Bacteria: A Comparison of Cell Shape Mechanisms in Proteobacteria.
Abstract Helical cell shape appears throughout the bacterial phylogenetic tree. Recent exciting work characterizing cell shape mutants in a number of curved and helical Proteobacteria is beginning to suggest possible mechanisms and provide tools to assess functional significance. We focus here on Caulobacter crescentus, Vibrio cholerae, Helicobacter pylori, and Campylobacter jejuni, organisms from three classes of Proteobacteria that live in diverse environments, from freshwater and saltwater to distinct compartments within the gastrointestinal tract of humans and birds. Comparisons among these bacteria reveal com...
Source: Annual Review of Microbiology - June 14, 2019 Category: Microbiology Authors: Taylor JA, Sichel SR, Salama NR Tags: Annu Rev Microbiol Source Type: research

Acinetobacter baumannii: Envelope Determinants That Control Drug Resistance, Virulence, and Surface Variability.
Abstract Acinetobacter baumannii has emerged as an important nosocomial pathogen, particularly for patients in intensive care units and with invasive indwelling devices. The most recent clinical isolates are resistant to several classes of clinically important antibiotics, greatly restricting the ability to effectively treat critically ill patients. The bacterial envelope is an important driver of A. baumannii disease, both at the level of battling against antibiotic therapy and at the level of protecting from host innate immune function. This review provides a comprehensive overview of key features of the envelop...
Source: Annual Review of Microbiology - June 14, 2019 Category: Microbiology Authors: Geisinger E, Huo W, Hernandez-Bird J, Isberg RR Tags: Annu Rev Microbiol Source Type: research

Phage Therapy in the Twenty-First Century: Facing the Decline of The Antibiotic Era; Is it Finally Time for The Age of the Phage?
Abstract Burgeoning problems of antimicrobial resistance dictate that new solutions be developed to combat old foes. Use of lytic bacteriophages (phages) for the treatment of drug-resistant bacterial infections is one approach that has gained significant traction in recent years. Fueled by reports of experimental phage therapy cases with very positive patient outcomes, several early-stage clinical trials of therapeutic phage products have been launched in the United States. Eventual licensure enabling widespread access to phages is the goal; however, new paths to regulatory approval and mass-market distribution, d...
Source: Annual Review of Microbiology - June 11, 2019 Category: Microbiology Authors: Hesse S, Adhya S Tags: Annu Rev Microbiol Source Type: research

Biogeography of the Oral Microbiome: The Site-Specialist Hypothesis.
Abstract Microbial communities are complex and dynamic, composed of hundreds of taxa interacting across multiple spatial scales. Advances in sequencing and imaging technology have led to great strides in understanding both the composition and the spatial organization of these complex communities. In the human mouth, sequencing results indicate that distinct sites host microbial communities that not only are distinguishable but to a meaningful degree are composed of entirely different microbes. Imaging suggests that the spatial organization of these communities is also distinct. Together, the literature supports th...
Source: Annual Review of Microbiology - June 10, 2019 Category: Microbiology Authors: Welch JLM, Dewhirst FE, Borisy GG Tags: Annu Rev Microbiol Source Type: research

Responses of Microorganisms to Osmotic Stress.
r R Abstract The cytoplasm of bacterial cells is a highly crowded cellular compartment that possesses considerable osmotic potential. As a result, and owing to the semipermeable nature of the cytoplasmic membrane and the semielastic properties of the cell wall, osmotically driven water influx will generate turgor, a hydrostatic pressure considered critical for growth and viability. Both increases and decreases in the external osmolarity inevitably trigger water fluxes across the cytoplasmic membrane, thus impinging on the degree of cellular hydration, molecular crowding, magnitude of turgor, and cellular integrity...
Source: Annual Review of Microbiology - June 10, 2019 Category: Microbiology Authors: Bremer E, Krämer R Tags: Annu Rev Microbiol Source Type: research

The Ultimate Guide to Bacterial Swarming: An Experimental Model to Study the Evolution of Cooperative Behavior.
Abstract Cooperation has fascinated biologists since Darwin. How did cooperative behaviors evolve despite the fitness cost to the cooperator? Bacteria have cooperative behaviors that make excellent models to take on this age-old problem from both proximate (molecular) and ultimate (evolutionary) angles. We delve into Pseudomonas aeruginosa swarming, a phenomenon where billions of bacteria move cooperatively across distances of centimeters in a matter of a few hours. Experiments with swarming have unveiled a strategy called metabolic prudence that stabilizes cooperation, have showed the importance of spatial struct...
Source: Annual Review of Microbiology - June 10, 2019 Category: Microbiology Authors: Yan J, Monaco HT, Xavier JB Tags: Annu Rev Microbiol Source Type: research

Algal Sex Determination and the Evolution of Anisogamy.
Abstract Algae are photosynthetic eukaryotes whose taxonomic breadth covers a range of life histories, degrees of cellular and developmental complexity, and diverse patterns of sexual reproduction. These patterns include haploid- and diploid-phase sex determination, and isogamous mating systems, and dimorphic sexes. Despite the ubiquity of sexual reproduction in algae, their mating-type-determination and sex-determination mechanisms have been investigated in only a limited number of representatives. These include volvocine green algae, where sexual cycles and sex-determining mechanisms have shed light on the trans...
Source: Annual Review of Microbiology - May 31, 2019 Category: Microbiology Authors: Umen J, Coelho S Tags: Annu Rev Microbiol Source Type: research

Tc Toxin Complexes: Assembly, Membrane Permeation, and Protein Translocation.
Abstract Tc toxin complexes are virulence factors of many bacteria, including insect and human pathogens. Tc toxins are composed of three subunits that act together to perforate the host membrane, similar to a syringe, and translocate toxic enzymes into the host cell. The reactions of the toxic enzymes lead to deterioration and ultimately death of the host cell. We review recent high-resolution structural and functional data that explain the mechanism of action of this type of bacterial toxin at an unprecedented level of molecular detail. We focus on the steps that are necessary for toxin activation and membrane p...
Source: Annual Review of Microbiology - May 29, 2019 Category: Microbiology Authors: Roderer D, Raunser S Tags: Annu Rev Microbiol Source Type: research

Functional Regulators of Bacterial Flagella.
Abstract Bacteria move by a variety of mechanisms, but the best understood types of motility are powered by flagella (72). Flagella are complex machines embedded in the cell envelope with a long extracellular helical filament and rotates like a propeller to push cells through the environment. The flagellum is one of relatively few biological machines that experience continuous 360° rotation, and it is driven by one of the most powerful motors, relative to its size, on earth. The rotational force (torque) generated at the base of the flagellum is essential for motility, niche colonization, and pathogenesis. Thi...
Source: Annual Review of Microbiology - May 28, 2019 Category: Microbiology Authors: Subramanian S, Kearns DB Tags: Annu Rev Microbiol Source Type: research

Multikinase Networks: Two-Component Signaling Networks Integrating Multiple Stimuli.
Abstract Bacteria depend on two-component systems to detect and respond to threats. Simple pathways comprise a single sensor kinase (SK) that detects a signal and activates a response regulator protein to mediate an appropriate output. These simple pathways with only a single SK are not well suited to making complex decisions where multiple different stimuli need to be evaluated. A recently emerging theme is the existence of multikinase networks (MKNs) where multiple SKs collaborate to detect and integrate numerous different signals to regulate a major lifestyle switch, e.g., between virulence, sporulation, biofil...
Source: Annual Review of Microbiology - May 21, 2019 Category: Microbiology Authors: Francis VI, Porter SL Tags: Annu Rev Microbiol Source Type: research

Posttranscription Initiation Control of Gene Expression Mediated by Bacterial RNA-Binding Proteins.
Abstract RNA-binding proteins play vital roles in regulating gene expression and cellular physiology in all organisms. Bacterial RNA-binding proteins can regulate transcription termination via attenuation or antitermination mechanisms, while others can repress or activate translation initiation by affecting ribosome binding. The RNA targets for these proteins include short repeated sequences, longer single-stranded sequences, RNA secondary or tertiary structure, and a combination of these features. The activity of these proteins can be influenced by binding of metabolites, small RNAs, or other proteins, as well as...
Source: Annual Review of Microbiology - May 17, 2019 Category: Microbiology Authors: Babitzke P, Lai YJ, Renda A, Romeo T Tags: Annu Rev Microbiol Source Type: research

Structural Basis of Response Regulator Function.
This article provides a framework for understanding structural features that enable function of canonical response regulators and a basis for distinguishing noncanonical configurations. Expected final online publication date for the Annual Review of Microbiology Volume 73 is September 9, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates. PMID: 31100988 [PubMed - as supplied by publisher] (Source: Annual Review of Microbiology)
Source: Annual Review of Microbiology - May 17, 2019 Category: Microbiology Authors: Gao R, Bouillet S, Stock AM Tags: Annu Rev Microbiol Source Type: research

Ecology and Evolution of Plant Microbiomes.
rs JM Abstract Microorganisms colonizing plant surfaces and internal tissues provide a number of life-support functions for their host. Despite increasing recognition of the vast functional capabilities of the plant microbiome, our understanding of the ecology and evolution of the taxonomically hyperdiverse microbial communities is limited. Here, we review current knowledge of plant genotypic and phenotypic traits as well as allogenic and autogenic factors that shape microbiome composition and functions. We give specific emphasis to the impact of plant domestication on microbiome assembly and how insights into mic...
Source: Annual Review of Microbiology - May 15, 2019 Category: Microbiology Authors: Cordovez V, Dini-Andreote F, Carrión VJ, Raaijmakers JM Tags: Annu Rev Microbiol Source Type: research

Cellular Functions and Mechanisms of Action of Small Heat Shock Proteins.
Abstract Small heat shock proteins (sHsps) constitute a diverse chaperone family that shares the α-crystallin domain, which is flanked by variable, disordered N- and C-terminal extensions. sHsps act as the first line of cellular defense against protein unfolding stress. They form dynamic, large oligomers that represent inactive storage forms. Stress conditions cause a rapid increase in cellular sHsp levels and trigger conformational rearrangements, resulting in exposure of substrate-binding sites and sHsp activation. sHsps bind to early-unfolding intermediates of misfolding proteins in an ATP-independent man...
Source: Annual Review of Microbiology - May 15, 2019 Category: Microbiology Authors: Mogk A, Ruger-Herreros C, Bukau B Tags: Annu Rev Microbiol Source Type: research

Protein Acetylation in Bacteria.
Abstract Acetylation is a posttranslational modification conserved in all domains of life that is carried out by N-acetyltransferases. While acetylation can occur on Nα-amino groups, this review will focus on Nε-acetylation of lysyl residues and how the posttranslational modification changes the cellular physiology of bacteria. Up until the late 1990s, acetylation was studied in eukaryotes in the context of chromatin maintenance and gene expression. At present, bacterial protein acetylation plays a prominent role in central and secondary metabolism, virulence, transcription, and translation. Given th...
Source: Annual Review of Microbiology - May 15, 2019 Category: Microbiology Authors: VanDrisse CM, Escalante-Semerena JC Tags: Annu Rev Microbiol Source Type: research

Life Cycle of Cryptococcus neoformans.
Abstract Cryptococcus neoformans is a ubiquitous environmental fungus and an opportunistic pathogen that causes fatal cryptococcal meningitis. Advances in genomics, genetics, and cellular and molecular biology of C. neoformans have dramatically improved our understanding of this important pathogen, rendering it a model organism to study eukaryotic biology and microbial pathogenesis. In light of recent progress, we describe in this review the life cycle of C. neoformans with a special emphasis on the regulation of the yeast-to-hypha transition and different modes of sexual reproduction, in addition to the impacts o...
Source: Annual Review of Microbiology - May 13, 2019 Category: Microbiology Authors: Zhao Y, Lin J, Fan Y, Lin X Tags: Annu Rev Microbiol Source Type: research

Introduction.
PMID: 30200847 [PubMed - in process] (Source: Annual Review of Microbiology)
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Gottesman S Tags: Annu Rev Microbiol Source Type: research

Broadening the Definition of Bacterial Small RNAs: Characteristics and Mechanisms of Action.
te; E Abstract The first report of trans-acting RNA-based regulation in bacterial cells dates back to 1984. Subsequent studies in diverse bacteria unraveled shared properties of trans-acting small regulatory RNAs, forming a clear definition of these molecules. These shared characteristics have been used extensively to identify new small RNAs (sRNAs) and their interactomes. Recently however, emerging technologies able to resolve RNA-RNA interactions have identified new types of regulatory RNAs. In this review, we present a broader definition of trans-acting sRNA regulators and discuss their newly discovered intrins...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Carrier MC, Lalaouna D, Massé E Tags: Annu Rev Microbiol Source Type: research

Pneumococcal Vaccines: Host Interactions, Population Dynamics, and Design Principles.
ey SD Abstract Streptococcus pneumoniae (the pneumococcus) is a nasopharyngeal commensal and respiratory pathogen. Most isolates express a capsule, the species-wide diversity of which has been immunologically classified into ∼100 serotypes. Capsule polysaccharides have been combined into multivalent vaccines widely used in adults, but the T cell independence of the antibody response means they are not protective in infants. Polysaccharide conjugate vaccines (PCVs) trigger a T cell-dependent response through attaching a carrier protein to capsular polysaccharides. The immune response stimulated by PCVs in infan...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Croucher NJ, Løchen A, Bentley SD Tags: Annu Rev Microbiol Source Type: research

Antibiotic-Induced Genetic Variation: How It Arises and How It Can Be Prevented.
cute;n J, Matic I Abstract By targeting essential cellular processes, antibiotics provoke metabolic perturbations and induce stress responses and genetic variation in bacteria. Here we review current knowledge of the mechanisms by which these molecules generate genetic instability. They include production of reactive oxygen species, as well as induction of the stress response regulons, which lead to enhancement of mutation and recombination rates and modulation of horizontal gene transfer. All these phenomena influence the evolution and spread of antibiotic resistance. The use of strategies to stop or decrease the...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Blázquez J, Rodríguez-Beltrán J, Matic I Tags: Annu Rev Microbiol Source Type: research

Ebola: Lessons on Vaccine Development.
Abstract The West African Ebola virus (EBOV) epidemic has fast-tracked countermeasures for this rare, emerging zoonotic pathogen. Until 2013-2014, most EBOV vaccine candidates were stalled between the preclinical and clinical milestones on the path to licensure, because of funding problems, lack of interest from pharmaceutical companies, and competing priorities in public health. The unprecedented and devastating epidemic propelled vaccine candidates toward clinical trials that were initiated near the end of the active response to the outbreak. Those trials did not have a major impact on the epidemic but provided ...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Feldmann H, Feldmann F, Marzi A Tags: Annu Rev Microbiol Source Type: research

The Glyoxylate Shunt, 60 Years On.
Abstract 2017 marks the 60th anniversary of Krebs' seminal paper on the glyoxylate shunt (and coincidentally, also the 80th anniversary of his discovery of the citric acid cycle). Sixty years on, we have witnessed substantial developments in our understanding of how flux is partitioned between the glyoxylate shunt and the oxidative decarboxylation steps of the citric acid cycle. The last decade has shown us that the beautifully elegant textbook mechanism that regulates carbon flux through the shunt in E. coli is an oversimplification of the situation in many other bacteria. The aim of this review is to assess how ...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Dolan SK, Welch M Tags: Annu Rev Microbiol Source Type: research

The Outer Membrane Took Center Stage.
Abstract My interest in membranes was piqued during a lecture series given by one of the founders of molecular biology, Max Delbrück, at Caltech, where I spent a postdoctoral year to learn more about protein chemistry. That general interest was further refined to my ultimate research focal point-the outer membrane of Escherichia coli-through the influence of the work of Wolfhard Weidel, who discovered the murein (peptidoglycan) layer and biochemically characterized the first phage receptors of this bacterium. The discovery of lipoprotein bound to murein was completely unexpected and demonstrated that the prot...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Braun V Tags: Annu Rev Microbiol Source Type: research

Detection of Microbial Infections Through Innate Immune Sensing of Nucleic Acids.
Abstract Microbial infections are recognized by the innate immune system through germline-encoded pattern recognition receptors (PRRs). As most microbial pathogens contain DNA and/or RNA during their life cycle, nucleic acid sensing has evolved as an essential strategy for host innate immune defense. Pathogen-derived nucleic acids with distinct features are recognized by specific host PRRs localized in endolysosomes and the cytosol. Activation of these PRRs triggers signaling cascades that culminate in the production of type I interferons and proinflammatory cytokines, leading to induction of an antimicrobial stat...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Tan X, Sun L, Chen J, Chen ZJ Tags: Annu Rev Microbiol Source Type: research

A New Lens for RNA Localization: Liquid-Liquid Phase Separation.
Abstract RNA localization mechanisms have been intensively studied and include localized protection of mRNA from degradation, diffusion-coupled local entrapment of mRNA, and directed transport of mRNAs along the cytoskeleton. While it is well understood how cells utilize these three mechanisms to organize mRNAs within the cytoplasm, a newly appreciated mechanism of RNA localization has emerged in recent years in which mRNAs phase-separate and form liquid-like droplets. mRNAs both contribute to condensation of proteins into liquid-like structures and are themselves regulated by being incorporated into membraneless ...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Langdon EM, Gladfelter AS Tags: Annu Rev Microbiol Source Type: research

The Promise of a Malaria Vaccine-Are We Closer?
Abstract Malaria vaccine development has rapidly advanced in the past decade. The very first phase 3 clinical trial of the RTS,S vaccine was completed with over 15,000 African infants and children, and pilot implementation studies are underway. Next-generation candidate vaccines using novel antigens, platforms, or approaches targeting different and/or multiple stages of the Plasmodium life cycle are being tested. Many candidates, in various stages of development, promise enhanced efficacy of long duration and broad protection against genetically diverse malaria strains, with a few studies under way in target popul...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Laurens MB Tags: Annu Rev Microbiol Source Type: research

Transcriptional Responses to ppGpp and DksA.
Abstract The stringent response to nutrient deprivation is a stress response found throughout the bacterial domain of life. Although first described in proteobacteria for matching ribosome synthesis to the cell's translation status and for preventing formation of defective ribosomal particles, the response is actually much broader, regulating many hundreds of genes-some positively, some negatively. Utilization of the signaling molecules ppGpp and pppGpp for this purpose is ubiquitous in bacterial evolution, although the mechanisms employed vary. In proteobacteria, the signaling molecules typically bind to two site...
Source: Annual Review of Microbiology - September 8, 2018 Category: Microbiology Authors: Gourse RL, Chen AY, Gopalkrishnan S, Sanchez-Vazquez P, Myers A, Ross W Tags: Annu Rev Microbiol Source Type: research

Using Cryo-EM to Investigate Bacterial Secretion Systems.
We describe how such techniques have contributed to knowledge of the mechanism of macromolecule secretion in bacteria and the impact they will have in the future. Expected final online publication date for the Annual Review of Microbiology Volume 72 is September 8, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates. PMID: 30004822 [PubMed - as supplied by publisher] (Source: Annual Review of Microbiology)
Source: Annual Review of Microbiology - July 13, 2018 Category: Microbiology Authors: Rapisarda C, Tassinari M, Gubellini F, Fronzes R Tags: Annu Rev Microbiol Source Type: research

Regulation of Sexual Commitment and Gametocytogenesis in Malaria Parasites.
e;s M Abstract Sexual differentiation of malaria parasites from the asexual blood stage into gametocytes is an essential part of the life cycle, as gametocytes are the form that is taken up by the mosquito host. Because of the essentiality of this process for transmission to the mosquito, gametocytogenesis is an extremely attractive target for therapeutic interventions. The subject of this review is the considerable progress that has been made in recent years in elucidating the molecular mechanisms governing this important differentiation process. In particular, a number of critical transcription factors and epige...
Source: Annual Review of Microbiology - July 5, 2018 Category: Microbiology Authors: Josling GA, Williamson KC, Llinás M Tags: Annu Rev Microbiol Source Type: research

The Epigenome, Cell Cycle, and Development in Toxoplasma.
Abstract Toxoplasma gondii is a common veterinary and human pathogen that persists as latent bradyzoite forms within infected hosts. The ability of the parasite to interconvert between tachyzoite and bradyzoite is key for pathogenesis of toxoplasmosis, particularly in immunocompromised individuals. The transition between tachyzoites and bradyzoites is epigenetically regulated and coupled to the cell cycle. Recent epigenomic studies have begun to elucidate the chromatin states associated with developmental switches in T. gondii. Evidence is also emerging that AP2 transcription factors both activate and repress the ...
Source: Annual Review of Microbiology - June 22, 2018 Category: Microbiology Authors: Kim K Tags: Annu Rev Microbiol Source Type: research

Epigenetic Variation and Regulation in Malaria Parasites.
Abstract Eukaryotic pathogens must survive in different hosts, respond to changing environments, and exploit specialized niches to propagate. Plasmodium parasites cause human malaria during bloodstream infections, where they must persist long enough to be transmitted. Parasites have evolved diverse strategies of variant gene expression that control critical biological processes of blood-stage infections, including antigenic variation, erythrocyte invasion, innate immune evasion, and nutrient acquisition, as well as life-cycle transitions. Epigenetic mechanisms within the parasite are being elucidated, with discove...
Source: Annual Review of Microbiology - June 21, 2018 Category: Microbiology Authors: Duraisingh MT, Skillman KM Tags: Annu Rev Microbiol Source Type: research

Communication Between the Microbiota and Mammalian Immunity.
Abstract Mammalian immune systems evolved within a diverse world dominated by microbes, making interactions between these two life-forms inevitable. Adaptive immunity protects against microbes through antigen-specific responses. In classical studies, these responses were investigated in the context of pathogenicity; however, we now know that they have significant effects on our resident microbes. In turn, microbes employ an arsenal of mechanisms to influence development and specificity of host immunity. Understanding these complex reactions will be necessary to develop microbiota-based strategies to prevent or tre...
Source: Annual Review of Microbiology - June 21, 2018 Category: Microbiology Authors: Ost KS, Round JL Tags: Annu Rev Microbiol Source Type: research

Interspecific Gene Exchange as a Driver of Adaptive Evolution in Fungi.
Abstract Throughout evolutionary history in the kingdom Fungi, taxa have exchanged genetic information among species, as revealed in particular by analyses of genome sequences. In fungi, hybridization can occur by sexual mating or by fusion of vegetative structures giving rise to new species or leaving traces of introgression in the genome. Furthermore, gene exchange can occur by horizontal gene transfer between species and can even include organisms outside the kingdom Fungi. In several cases, interspecific gene exchange has been instrumental in rapid adaptive evolution of fungal species and has notably played a ...
Source: Annual Review of Microbiology - June 21, 2018 Category: Microbiology Authors: Feurtey A, Stukenbrock EH Tags: Annu Rev Microbiol Source Type: research

Spo11-Independent Meiosis in Social Amoebae.
Abstract Sex in social amoebae (or dictyostelids) has a number of striking features. Dictyostelid zygotes do not proliferate but grow to a large size by feeding on other cells of the same species, each zygote ultimately forming a walled structure called a macrocyst. The diploid macrocyst nucleus undergoes meiosis, after which a single meiotic product survives to restart haploid vegetative growth. Meiotic recombination is generally initiated by the Spo11 enzyme, which introduces DNA double-strand breaks. Uniquely, as far as is known among sexual eukaryotes, dictyostelids lack a SPO11 gene. Despite this, recombinati...
Source: Annual Review of Microbiology - June 20, 2018 Category: Microbiology Authors: Bloomfield G Tags: Annu Rev Microbiol Source Type: research

Electron Bifurcation: A Long-Hidden Energy-Coupling Mechanism.
n M Abstract A decade ago, a novel mechanism to drive thermodynamically unfavorable redox reactions was discovered that is used in prokaryotes to drive endergonic electron transfer reactions by a direct coupling to an exergonic redox reaction in one soluble enzyme complex. This process is referred to as flavinbased electron bifurcation, or FBEB. An important function of FBEB is that it allows the generation of reduced low-potential ferredoxin (Fdred) from comparably high-potential electron donors such as NADH or molecular hydrogen (H2). Fdred is then the electron donor for anaerobic respiratory chains leading to t...
Source: Annual Review of Microbiology - June 20, 2018 Category: Microbiology Authors: Müller V, Chowdhury NP, Basen M Tags: Annu Rev Microbiol Source Type: research