Functional roles and metabolic niches in the honey bee gut microbiota.
Abstract Gut microbiota studies on diverse animals facilitate our understanding of the general principles governing microbiota-host interactions. The honey bee adds a relevant study system due to the simplicity and experimental tractability of its gut microbiota, but also because bees are important pollinators that suffer from population declines worldwide. The use of gnotobiotic bees combined with genetic tools, 'omics' analysis, and experimental microbiology has recently provided important insights about the impact of the microbiota on bee health and the general functioning of gut ecosystems. PMID: 29309997...
Source: Current Opinion in Microbiology - January 5, 2018 Category: Microbiology Authors: Bonilla-Rosso G, Engel P Tags: Curr Opin Microbiol Source Type: research

Imaging bacteria inside their host by cryo-focused ion beam milling and electron cryotomography.
r M Abstract Bacterium-host interactions are important for diverse ecological settings including pathogenicity and symbiosis. Electron cryotomography is a powerful method for studying the macromolecular complexes that mediate such interactions in situ. The main limitation of electron cryotomography is its restriction to relatively thin samples such as individual bacterial cells. Cryo-focused ion beam milling was recently proposed as a solution to the thickness limitation. This approach allows the artifact-free thinning of biological specimens for subsequent imaging in the transmission electron microscope. By enabl...
Source: Current Opinion in Microbiology - December 29, 2017 Category: Microbiology Authors: Medeiros JM, Böck D, Pilhofer M Tags: Curr Opin Microbiol Source Type: research

The challenges of integrating two genomes in one cell.
SG Abstract Mutualistic bacteria and mitochondria have small genomes that harbor host-essential genes. A major question is why a distinct bacterial or mitochondrial genome is needed to encode these functions. The dual location of genes demand two sets of information processing systems, coordination of gene expression and elaborate transport systems. A simpler solution would be to harbor all genes in a single genome. Functional gene transfers to the host nuclear genome is uncommon in mutualistic bacteria and lost gene functions are rather rescued by co-symbiotic bacteria. Recent findings suggest that the mitochond...
Source: Current Opinion in Microbiology - December 22, 2017 Category: Microbiology Authors: Hagström E, Andersson SG Tags: Curr Opin Microbiol Source Type: research

Enterohemorrhagic Escherichia coli outwits hosts through sensing small molecules.
Abstract Small molecules help intestinal pathogens navigate the complex human gastrointestinal tract to exploit favorable microhabitats. These small molecules provide spatial landmarks for pathogens to regulate synthesis of virulence caches and are derived from the host, ingested plant and animal material, and the microbiota. Their concentrations and fluxes vary along the length of the gut and provide molecular signatures that are beginning to be explored through metabolomics and genetics. However, while many small molecules have been identified and are reviewed here, there are undoubtedly others that may also pro...
Source: Current Opinion in Microbiology - December 16, 2017 Category: Microbiology Authors: Carlson-Banning KM, Sperandio V Tags: Curr Opin Microbiol Source Type: research

Plasmodium P47: a key gene for malaria transmission by mosquito vectors.
Abstract Malaria is caused by infection with Plasmodium parasites that have a complex life cycle. The parasite protein P47 is critical for disease transmission. P47 mediates mosquito immune evasion in both Plasmodium berghei (Pbs47) and Plasmodium falciparum (Pfs47), and has been shown to be important for optimal female gamete fertility in P. berghei. Pfs47 presents strong geographic structure in natural P. falciparum populations, consistent with natural selection of Pfs47 haplotypes by the mosquito immune system as the parasite adapted to new vector species worldwide. These key functions make Plasmodium P47 an at...
Source: Current Opinion in Microbiology - December 8, 2017 Category: Microbiology Authors: Molina-Cruz A, Canepa GE, Barillas-Mury C Tags: Curr Opin Microbiol Source Type: research

The ultimate picture-the combination of live cell superresolution microscopy and single molecule tracking yields highest spatio-temporal resolution.
Abstract We are witnessing a breathtaking development in light (fluorescence) microscopy, where structures can be resolved down to the size of a ribosome within cells. This has already yielded surprising insight into the subcellular structure of cells, including the smallest cells, bacteria. Moreover, it has become possible to visualize and track single fluorescent protein fusions in real time, and quantify molecule numbers within individual cells. Combined, super resolution and single molecule tracking are pushing the limits of our understanding of the spatio-temporal organization even of the smallest cells to an...
Source: Current Opinion in Microbiology - December 8, 2017 Category: Microbiology Authors: Dersch S, Graumann PL Tags: Curr Opin Microbiol Source Type: research

Evolution of virulence in Enterococcus faecium, a hospital-adapted opportunistic pathogen.
Abstract Enterococci are long-standing members of the human microbiome and they are also widely distributed in nature. However, with the surge of antibiotic-resistance in recent decades, two enterococcal species (Enterococcus faecalis and Enterococcus faecium) have emerged to become significant nosocomial pathogens, acquiring extensive antibiotic resistance. In this review, we summarize what is known about the evolution of virulence in E. faecium, highlighting a specific clone of E. faecium called ST796 that has emerged recently and spread globally. PMID: 29227922 [PubMed - as supplied by publisher] (Source: ...
Source: Current Opinion in Microbiology - December 8, 2017 Category: Microbiology Authors: Gao W, Howden BP, Stinear TP Tags: Curr Opin Microbiol Source Type: research

Tissue-specific cellular immune responses to malaria pre-erythrocytic stages.
Abstract Complete and long-lasting protective immunity against malaria can be achieved through vaccination with invasive live attenuated Plasmodium sporozoites, the motile stage inoculated in the host skin during a mosquito bite. Protective immunity relies primarily on effector CD8+ T cells targeting the parasite in the liver. Understanding the tissue-specific features of the immune response is emerging as a vital requirement for understanding protective immunity. The small parasite inoculum, the scarcity of infected cells and the tolerogenic properties of the liver represent hurdles for the establishment of prote...
Source: Current Opinion in Microbiology - December 4, 2017 Category: Microbiology Authors: Silvie O, Amino R, Hafalla JC Tags: Curr Opin Microbiol Source Type: research

Evolution of virulence in the Mycobacterium tuberculosis complex.
Abstract Mycobacterium tuberculosis, the causative agent of human tuberculosis is one of the most widely spread human pathogens. It has succeeded to infect a quarter of the global human population by developing most sophisticated ways to circumvent innate and adaptive immune defences. This highly specialized, major human pathogen has evolved from a pool of ancestral environmental mycobacteria, whose extant representatives are known under the name of Mycobacterium canettii. Recent whole genome analyses in combination with different phenotypic screens have provided key insights into the evolution of M. tuberculosis ...
Source: Current Opinion in Microbiology - December 4, 2017 Category: Microbiology Authors: Orgeur M, Brosch R Tags: Curr Opin Microbiol Source Type: research

Road MAPs to engineer host microbiomes.
We present the MAPs-first approach, a theoretical and experimental roadmap that involves quantitative profiling of MAPs across genetically variable hosts and subsequent identification of the underlying mechanisms. We outline strategies for developing 'modular microbiomes'-synthetic microbial consortia that are engineered in concert with the host genotype to confer different but mutually compatible MAPs to a single host or host population. By integrating host and microbial traits, these strategies will facilitate targeted engineering of microbiomes to the benefit of agriculture, human/animal health and biotechnology. P...
Source: Current Opinion in Microbiology - December 2, 2017 Category: Microbiology Authors: Oyserman BO, Medema MH, Raaijmakers JM Tags: Curr Opin Microbiol Source Type: research

Regulation of host-pathogen interactions via the post-transcriptional Csr/Rsm system.
Abstract A successful colonization of specific hosts requires a rapid and efficient adaptation of the virulence-relevant gene expression program by bacterial pathogens. An important element in this endeavor is the Csr/Rsm system. This multi-component, post-transcriptional control system forms a central hub within complex regulatory networks and coordinately adjusts virulence properties with metabolic and physiological attributes of the pathogen. A key function is elicited by the RNA-binding protein CsrA/RsmA. CsrA/RsmA interacts with numerous target mRNAs, many of which encode crucial virulence factors, and alters...
Source: Current Opinion in Microbiology - December 2, 2017 Category: Microbiology Authors: Kusmierek M, Dersch P Tags: Curr Opin Microbiol Source Type: research

Colonization, localization, and inflammation: the roles of H. pylori chemotaxis in vivo.
Abstract Helicobacter pylori is a Gram-negative bacterium that infects half of the world's population, causing gastritis, peptic ulcers, and gastric cancer. To establish chronic stomach infection, H. pylori utilizes chemotaxis, driven by a conserved signal transduction system. Chemotaxis allows H. pylori to sense an array of environmental and bacterial signals within the stomach, guiding its motility towards its preferred niche within the gastric mucosa and glands. Fine-tuned localization, regulated by the chemotaxis system, enables robust colonization during the acute stage of infection. During chronic infection,...
Source: Current Opinion in Microbiology - December 1, 2017 Category: Microbiology Authors: Johnson KS, Ottemann KM Tags: Curr Opin Microbiol Source Type: research

Visualizing bacterial DNA replication and repair with molecular resolution.
Abstract Although DNA replication and repair in bacteria have been extensively studied for many decades, in recent years the development of single-molecule microscopy has provided a new perspective on these fundamental processes. Because single-molecule imaging super-resolves the nanometer-scale dynamics of molecules, and because single-molecule imaging is sensitive to heterogeneities within a sample, this nanoscopic microscopy technique measures the motions, localizations, and interactions of proteins in real time without averaging ensemble observations, both in vitro and in vivo. In this Review, we provide an ov...
Source: Current Opinion in Microbiology - November 30, 2017 Category: Microbiology Authors: Li Y, Schroeder JW, Simmons LA, Biteen JS Tags: Curr Opin Microbiol Source Type: research

After the deluge: mining Staphylococcus aureus genomic data for clinical associations and host-pathogen interactions.
Abstract The genome of Staphylococcus aureus has rapidly become one the most frequently sequenced among bacteria, with more than 40000 genome sequences uploaded to public databases. Computational resources required for analysis and quality assessment have lagged behind accumulation of sequence data. Improved analytic pipelines, in combination with the development of customized S. aureus reference databases, can be used to inform S. aureus biology and potentially predict clinical outcome. Here, we review the currently available data about S. aureus genome in public databases, and discuss their potential utility for...
Source: Current Opinion in Microbiology - November 30, 2017 Category: Microbiology Authors: Copin R, Shopsin B, Torres VJ Tags: Curr Opin Microbiol Source Type: research

Bacterial social interactions and the emergence of community-intrinsic properties.
slash;lle M Abstract Bacterial communities are dominated and shaped by social interactions, which facilitate the emergence of properties observed only in the community setting. Such community-intrinsic properties impact not only the phenotypes of cells in a community, but also community composition and function, and are thus likely to affect a potential host. Studying community-intrinsic properties is, therefore, important for furthering our understanding of clinical, applied and environmental microbiology. Here, we provide recent examples of research investigating community-intrinsic properties, focusing mainly o...
Source: Current Opinion in Microbiology - November 30, 2017 Category: Microbiology Authors: Madsen JS, Sørensen SJ, Burmølle M Tags: Curr Opin Microbiol Source Type: research

Legionella quorum sensing and its role in pathogen-host interactions.
Abstract Legionella pneumophila is a water-borne opportunistic pathogen causing a life-threatening pneumonia called 'Legionnaires' disease'. The Legionella quorum sensing (Lqs) system produces and responds to the α-hydroxyketone signaling molecule 3-hydroxypentadecane-4-one (Legionella autoinducer-1, LAI-1). The Lqs system controls the switch between the replicative/non-virulent and the transmissive/virulent phase of L. pneumophila, and it is a major regulator of natural competence, motility and virulence of the pathogen. Yet, beyond gene regulation, LAI-1 also directly affects pathogen-host interactions, si...
Source: Current Opinion in Microbiology - November 27, 2017 Category: Microbiology Authors: Personnic N, Striednig B, Hilbi H Tags: Curr Opin Microbiol Source Type: research

Lipid metabolism and its implication in mycobacteria-host interaction.
Abstract The complex lipids present in the cell wall of Mycobacterium tuberculosis (Mtb) act as major effector molecules that actively interact with the host, modulating its metabolism and stimulating the immune response, which in turn affects the physiology of both, the host cell and the bacilli. Lipids from the host are also nutrient sources for the pathogen and define the fate of the infection by modulating lipid homeostasis. Although new technologies and experimental models of infection have greatly helped understanding the different aspects of the host-pathogen interactions at the lipid level, the impact of t...
Source: Current Opinion in Microbiology - November 27, 2017 Category: Microbiology Authors: Gago G, Diacovich L, Gramajo H Tags: Curr Opin Microbiol Source Type: research

SMC complexes sweeping through the chromosome: going with the flow and against the tide.
Abstract Bacteria transcribe, duplicate and segregate their genomes all at once. Conflicts between DNA replication and active transcription are a major source of DNA damage and jeopardize genome integrity and cell survival. Co-orientation of replication forks and transcription units is thought to reduce the impact of such conflicts. Like transcription and replication, chromosome segregation relies on the translocation of multi-subunit protein complexes along DNA. Here, I highlight recent advances in our understanding of two major classes of structural maintenance of chromosomes (SMC) complexes in bacteria: Smc-Scp...
Source: Current Opinion in Microbiology - November 25, 2017 Category: Microbiology Authors: Gruber S Tags: Curr Opin Microbiol Source Type: research

Host-pathogen systems for early drug discovery against tuberculosis.
Abstract Tuberculosis (TB) is a global disease causing 1.8 million deaths each year. The appearance of drug-resistant strains raised the demand for new anti-mycobacterial drugs and therapies, because previously discovered antibiotics are shown to be inefficient. Moreover, the number of newly discovered drugs is not increasing in proportion to the emergence of drug resistance, which suggests that more optimized methodology and screening procedures are required including the incorporation of in vivo properties of TB infection. A way to improve efficacy of screening approaches is by introducing the use of different h...
Source: Current Opinion in Microbiology - November 24, 2017 Category: Microbiology Authors: Trofimov V, Costa-Gouveia J, Hoffmann E, Brodin P Tags: Curr Opin Microbiol Source Type: research

Discovery of new RNA classes and global RNA-binding proteins.
l J Abstract The identification of new RNA functions and the functional annotation of transcripts in genomes represent exciting yet challenging endeavours of modern biology. Crucial insights into the biological roles of RNA molecules can be gained from the identification of the proteins with which they form specific complexes. Modern interactome techniques permit to profile RNA-protein interactions in a genome-wide manner and identify new RNA classes associated with globally acting RNA-binding proteins. Applied to a variety of organisms, these methods are already revolutionising our understanding of RNA-mediated b...
Source: Current Opinion in Microbiology - November 24, 2017 Category: Microbiology Authors: Smirnov A, Schneider C, Hör J, Vogel J Tags: Curr Opin Microbiol Source Type: research

Metal-homeostasis in the pathobiology of the opportunistic human fungal pathogen Aspergillus fumigatus.
e; JP Abstract In contrast to obligate pathogens opportunistic pathogens such as Aspergillus fumigatus do not need a specific host to propagate or survive. However several characteristics of the saprophytic life-style and the selective pressure encountered in the primary ecological niche contribute to the virulence of A. fumigatus. All fungi depend on metals for growth and proliferation, like iron, copper, zinc, manganese or calcium. In the recent past several studies explored the manifold impact of metals modulating virulence of pathogens. Components which might be scarce in the natural environment but also in th...
Source: Current Opinion in Microbiology - November 24, 2017 Category: Microbiology Authors: Blatzer M, Latgé JP Tags: Curr Opin Microbiol Source Type: research

Omics-based natural product discovery and the lexicon of genome mining.
Abstract Genome sequencing and the application of omic techniques are driving many important advances in the field of microbial natural products research. Despite these gains, there remain aspects of the natural product discovery pipeline where our knowledge remains poor. These include the extent to which biosynthetic gene clusters are transcriptionally active in native microbes, the temporal dynamics of transcription, translation, and natural product assembly, as well as the relationships between small molecule production and detection. Here we touch on a number of these concepts in the context of continuing effo...
Source: Current Opinion in Microbiology - November 23, 2017 Category: Microbiology Authors: Machado H, Tuttle RN, Jensen PR Tags: Curr Opin Microbiol Source Type: research

Host-microbe interactions: commensal fungi in the gut.
Abstract Fungi are ubiquitous microbes that are common in diverse environments including as commensal organisms on the human body. In addition to its obvious role as a digestive organ, the intestines have been further appreciated as important for the development, maintenance, and instruction of the immune system. The gut harbors many types of microorganisms including bacteria, archaea, fungi, and viruses, and many studies over the past couple of decades have documented an important role for intestinal bacteria in immunological function. Recent studies are now suggesting that intestinal fungi (the gut 'mycobiome') ...
Source: Current Opinion in Microbiology - November 22, 2017 Category: Microbiology Authors: Paterson MJ, Oh S, Underhill DM Tags: Curr Opin Microbiol Source Type: research

Molecular mechanisms of deformability of Plasmodium-infected erythrocytes.
Abstract In physiological conditions, normal erythrocytes are highly deformable due to their high surface area to volume ratio, their moderate cytoplasmic viscosity and the elasticity of their membrane skeleton. Infection with the human malaria parasite Plasmodium falciparum induces dramatic changes in cellular deformability and membrane elasticity of their host erythrocyte, in part due to the shape and the volume of the parasite itself, and to the export of parasite proteins that interact with host membrane skeletal proteins. These changes in deformability are tightly regulated by the parasite and may reflect a s...
Source: Current Opinion in Microbiology - November 22, 2017 Category: Microbiology Authors: Lavazec C Tags: Curr Opin Microbiol Source Type: research

Membrane trafficking and remodeling at the host-parasite interface.
Abstract Membrane shape is functionally linked with many cellular processes. The limiting membrane of vacuoles containing Toxoplasma gondii and Plasmodium apicomplexan parasites lies at the host-parasite interface. This membrane comprises intra-vacuolar and extra-vacuolar tubulo-vesicular deformations, which influence host-parasite cross-talk. Here, underscoring specificities and similarities between the T. gondii and Plasmodium contexts, we present recent findings about vacuolar membrane remodeling and its potential roles in parasite fitness and immune recognition. We review in particular the implication of tubul...
Source: Current Opinion in Microbiology - November 22, 2017 Category: Microbiology Authors: Santi-Rocca J, Blanchard N Tags: Curr Opin Microbiol Source Type: research

Monitoring microbial communities using light sheet fluorescence microscopy.
Abstract Microbes often live in dense, dynamic, multi-species communities whose architecture and function are intimately intertwined. Imaging these complex, three-dimensional ensembles presents considerable technical challenges, however. In this review, I describe light sheet fluorescence microscopy, a technique that enables rapid acquisition of three-dimensional images over large fields of view and over long durations, and I highlight recent applications of this method to microbial systems that include artificial closed ecosystems, bacterial biofilms, and gut microbiota. I comment also on the history of light she...
Source: Current Opinion in Microbiology - November 22, 2017 Category: Microbiology Authors: Parthasarathy R Tags: Curr Opin Microbiol Source Type: research

Cyclic di-AMP in host-pathogen interactions.
Abstract Cyclic di-AMP (c-di-AMP) is a bacterial signaling nucleotide synthesized by several human pathogens. This widespread and specific bacterial product is recognized by infected host cells to trigger an innate immune response. Detection of c-di-AMP in the host cytosol leads primarily to the induction of type I interferon via the STING-cGAS signaling axis, while being also entangled in the activation of the NF-κB pathway. During their long-standing interaction, host and pathogens have co-evolved to control c-di-AMP activation of innate immunity. On the bacterial side, the quantity of c-di-AMP released in...
Source: Current Opinion in Microbiology - November 20, 2017 Category: Microbiology Authors: Devaux L, Kaminski PA, Trieu-Cuot P, Firon A Tags: Curr Opin Microbiol Source Type: research

Antimicrobial discovery inspired by ecological interactions.
Abstract Bacteria represent an unparalleled source of antibiotics used to treat infectious diseases. Yet, genome analyses have revealed that their full biosynthetic potential is much larger than expected. Valuable strategies to unearth hidden antibiotics are genome mining, pathway engineering and triggering, as well as co-cultivation approaches. Nevertheless, there is growing understanding that it is often essential to consider the ecological context and that there is a great potential for antimicrobial discovery from bacteria engaged in well-defined interactions with other organisms. Various ecological scenarios ...
Source: Current Opinion in Microbiology - November 20, 2017 Category: Microbiology Authors: Molloy EM, Hertweck C Tags: Curr Opin Microbiol Source Type: research

Systematically investigating the impact of medication on the gut microbiome.
Abstract In the recent years, there is accumulating evidence for a strong impact of medication on the gut microbiota composition. This evidence comes from metagenomics-based associations and extends beyond classical antibacterials to a handful of human-targeted drugs. To answer whether such effects are direct and explore their consequences in human health, we need to develop experimental platforms that will allow for systematic profiling of drug-microbiota interactions. Here, we discuss approaches, considerations, experimental setups and strategies that can be used to tackle this need, but can be also readily tran...
Source: Current Opinion in Microbiology - November 20, 2017 Category: Microbiology Authors: Maier L, Typas A Tags: Curr Opin Microbiol Source Type: research

How bacteria control the CRISPR-Cas arsenal.
Abstract CRISPR-Cas systems are adaptive immune systems that protect their hosts from predation by bacteriophages (phages) and parasitism by other mobile genetic elements (MGEs). Given the potent nuclease activity of CRISPR effectors, these enzymes must be carefully regulated to minimize toxicity and maximize anti-phage immunity. While attention has been given to the transcriptional regulation of these systems (reviewed in [1]), less consideration has been given to the crucial post-translational processes that govern enzyme activation and inactivation. Here, we review recent findings that describe how Cas nuclease...
Source: Current Opinion in Microbiology - November 20, 2017 Category: Microbiology Authors: Leon LM, Mendoza SD, Bondy-Denomy J Tags: Curr Opin Microbiol Source Type: research

C-type lectin receptors in anti-fungal immunity.
Abstract Host immune systems are constantly engaged with fungal pathogens which are common in environments as well as in healthy human skin and mucosa. C-type lectin receptors (CLRs) are expressed in myeloid cells and play central roles in host defenses against fungal infections by coordinating innate and adaptive immune systems. Upon ligand binding, CLRs stimulate cellular responses by inducing the production of cytokines and reactive oxygen species via the Syk/CARD9 signaling pathway, leading to fungal elimination. Due to identification and characterization of the CLRs, the underlying mechanisms of the anti-fung...
Source: Current Opinion in Microbiology - November 20, 2017 Category: Microbiology Authors: Shiokawa M, Yamasaki S, Saijo S Tags: Curr Opin Microbiol Source Type: research

More than a Tad: spatiotemporal control of Caulobacter pili.
Abstract The Type IV pilus (T4P) is a powerful and sophisticated bacterial nanomachine involved in numerous cellular processes, including adhesion, DNA uptake and motility. Aside from the well-described subtype T4aP of the Gram-negative genera, including Myxococcus, Pseudomonas and Neisseria, the Tad (tight adherence) pilus secretion system re-shuffles homologous parts from other secretion systems along with uncharacterized components into a new type of protein translocation apparatus. A representative of the Tad apparatus, the Caulobacter crescentus pilus assembly (Cpa) machine is built exclusively at the newborn...
Source: Current Opinion in Microbiology - November 18, 2017 Category: Microbiology Authors: Mignolet J, Panis G, Viollier PH Tags: Curr Opin Microbiol Source Type: research

Functions of myosin motors tailored for parasitism.
Abstract Myosin motors are one of the largest protein families in eukaryotes that exhibit divergent cellular functions. Their roles in protozoans, a diverse group of anciently diverged, single celled organisms with many prominent members known to be parasitic and to cause diseases in human and livestock, are largely unknown. In the recent years many different approaches, among them whole genome sequencing, phylogenetic analyses and functional studies have increased our understanding on the distribution, protein architecture and function of unconventional myosin motors in protozoan parasites. In Apicomplexa, myosin...
Source: Current Opinion in Microbiology - November 18, 2017 Category: Microbiology Authors: Mueller C, Graindorge A, Soldati-Favre D Tags: Curr Opin Microbiol Source Type: research

Lifestyle transitions and adaptive pathogenesis of Pseudomonas aeruginosa.
Abstract Pseudomonas aeruginosa acute and chronic infections are of great concern to human health, especially in hospital settings. It is currently assumed that P. aeruginosa has two antagonistic pathogenic strategies that parallel two different lifestyles; free-living cells are predominantly cytotoxic and induce an acute inflammatory reaction, while biofilm-forming communities cause refractory chronic infections. Recent findings suggest that the planktonic-to-sessile transition is a complex, reversible and overall dynamic differentiation process. Here, we examine how the Gac/Rsm regulatory cascade, a key player i...
Source: Current Opinion in Microbiology - November 18, 2017 Category: Microbiology Authors: Valentini M, Gonzalez D, Mavridou DA, Filloux A Tags: Curr Opin Microbiol Source Type: research

Candida albicans-epithelial interactions and induction of mucosal innate immunity.
SL Abstract Candida albicans is a human fungal pathogen that causes millions of mucosal and life-threatening infections annually. C. albicans initially interacts with epithelial cells, resulting in fungal recognition and the formation of hyphae. Hypha formation is critical for host cell damage and immune activation, which are both driven by the secretion of Candidalysin, a recently discovered peptide toxin. Epithelial activation leads to the production of inflammatory mediators that recruit innate immune cells including neutrophils, macrophages and innate Type 17 cells, which together work with epithelial cells t...
Source: Current Opinion in Microbiology - November 17, 2017 Category: Microbiology Authors: Naglik JR, König A, Hube B, Gaffen SL Tags: Curr Opin Microbiol Source Type: research

Bacterial microbiota of the nasal passages across the span of human life.
Abstract The human nasal passages host major human pathogens. Recent research suggests that the microbial communities inhabiting the epithelial surfaces of the nasal passages are a key factor in maintaining a healthy microenvironment by affecting both resistance to pathogens and immunological responses. The nasal bacterial microbiota shows distinct changes over the span of human life and disruption by environmental factors might be associated with both short- and long-term health consequences, such as susceptibility to viral and bacterial infections and disturbances of the immunological balance. Because infants an...
Source: Current Opinion in Microbiology - November 17, 2017 Category: Microbiology Authors: Bomar L, Brugger SD, Lemon KP Tags: Curr Opin Microbiol Source Type: research

Survival of microbes in Earth's stratosphere.
Abstract The remarkable survival of microorganisms high above the surface of the Earth is of increasing interest. At stratospheric levels, multiple stressors including ultraviolet and ionizing radiation, low temperatures, hypobaric conditions, extreme desiccation, and nutrient scarcity are all significant challenges. Our understanding of which microorganisms are capable of tolerating such stressful conditions has been addressed by stratospheric sample collection and survival assays, through launching and recovery, and exposure to simulated conditions in the laboratory. Here, we review stratospheric microbiology st...
Source: Current Opinion in Microbiology - November 17, 2017 Category: Microbiology Authors: DasSarma P, DasSarma S Tags: Curr Opin Microbiol Source Type: research

Recent development of computational resources for new antibiotics discovery.
Abstract Understanding a complex working mechanism of biosynthetic gene clusters (BGCs) encoding secondary metabolites is a key to discovery of new antibiotics. Computational resources continue to be developed in order to better process increasing volumes of genome and chemistry data, and thereby better understand BGCs. In this context, this review highlights recent advances in computational resources for secondary metabolites with emphasis on genome mining, compound identification and dereplication as well as databases. We also introduce an updated version of Secondary Metabolite Bioinformatics Portal (SMBP; http...
Source: Current Opinion in Microbiology - November 16, 2017 Category: Microbiology Authors: Kim HU, Blin K, Lee SY, Weber T Tags: Curr Opin Microbiol Source Type: research

Global antimicrobial resistance in Gram-negative pathogens and clinical need.
Abstract Resistance in Gram-negative bacteria has become a serious problem in many regions of the world as it may reduce the treatment options substantially. Carbapenem-resistance is a good marker for such situations and is most prevalent in Acinetobacter, Pseudomonas but also increasingly in Enterobacteriaceae, especially Klebsiella. This review gives a rough global picture highlighting the epicentres of resistance. The medical need for novel treatment options globally is undeniable even if many countries with good stewardship and infection control conditions are not highly affected. Antibiotic pipelines are enco...
Source: Current Opinion in Microbiology - November 15, 2017 Category: Microbiology Authors: Theuretzbacher U Tags: Curr Opin Microbiol Source Type: research

Alternative transcriptional regulation in genome-reduced bacteria.
ano L Abstract Transcription is a core process of bacterial physiology, and as such it must be tightly controlled, so that bacterial cells maintain steady levels of each RNA molecule in homeostasis and modify them in response to perturbations. The major regulators of transcription in bacteria (and in eukaryotes) are transcription factors. However, in genome-reduced bacteria, the limited number of these proteins is insufficient to explain the variety of responses shown upon changes in their environment. Thus, alternative regulators may play a central role in orchestrating RNA levels in these microorganisms. These a...
Source: Current Opinion in Microbiology - November 15, 2017 Category: Microbiology Authors: Miravet-Verde S, Lloréns-Rico V, Serrano L Tags: Curr Opin Microbiol Source Type: research

Inhibitors of metallo- β-lactamases.
Inhibitors of metallo-β-lactamases. Curr Opin Microbiol. 2017 Nov 15;39:96-105 Authors: Rotondo CM, Wright GD Abstract The β-lactams are the most successful class of antibiotic drugs but they are vulnerable to inactivation by a growing cadre of β-lactamases that now number more than a thousand variants. β-Lactamases operate by one of two general chemical mechanisms either catalyzing β-lactam ring hydrolysis via a covalent enzyme intermediate through the aegis of an active site serine residue or through a noncovalent Zn-dependent mechanism. The Ser-β-lactamases are current...
Source: Current Opinion in Microbiology - November 15, 2017 Category: Microbiology Authors: Rotondo CM, Wright GD Tags: Curr Opin Microbiol Source Type: research

The cause and effect of Cryptococcus interactions with the host.
Abstract Upon Cryptococcus neoformans infection of the host lung, the fungus enters a nutrient poor environment and must adapt to a variety of host-specific stress conditions (temperature, nutrient limitation, pH, CO2). Fungal spores enter this milieu with limited nutritional reserves, germinate, and begin proliferating by budding as yeast. Although relatively little is known about the initial stages of infection, recent work has characterized changes that occur upon germination. This program and subsequent yeast-phase proliferation progress in a dynamic environment as host nutrient immunity responds to the infect...
Source: Current Opinion in Microbiology - November 15, 2017 Category: Microbiology Authors: Ballou ER, Johnston SA Tags: Curr Opin Microbiol Source Type: research

Modulating host immune responses to fight invasive fungal infections.
Abstract Modulation of host immunity in invasive fungal infection is an appealing but as yet mostly elusive treatment strategy. Animal studies in invasive candidiasis and aspergillosis have demonstrated beneficial effects of colony stimulating factors, interferon-gamma and monoclonal antibodies. More recent studies transfusing leukocytes pre-loaded with lipophilic anti-fungal drugs, or modulated T-cells, along with novel vaccination strategies show great promise. The translation of immune therapies into clinical studies has been limited to date but this is changing and the results of new Candida vaccine trials are...
Source: Current Opinion in Microbiology - November 15, 2017 Category: Microbiology Authors: Scriven JE, Tenforde MW, Levitz SM, Jarvis JN Tags: Curr Opin Microbiol Source Type: research

Metabolic-flux dependent regulation of microbial physiology.
ann M Abstract According to the most prevalent notion, changes in cellular physiology primarily occur in response to altered environmental conditions. Yet, recent studies have shown that changes in metabolic fluxes can also trigger phenotypic changes even when environmental conditions are unchanged. This suggests that cells have mechanisms in place to assess the magnitude of metabolic fluxes, that is, the rate of metabolic reactions, and use this information to regulate their physiology. In this review, we describe recent evidence for metabolic flux-sensing and flux-dependent regulation. Furthermore, we discuss ho...
Source: Current Opinion in Microbiology - November 15, 2017 Category: Microbiology Authors: Litsios A, Ortega ÁD, Wit EC, Heinemann M Tags: Curr Opin Microbiol Source Type: research

Rationale redesign of type III secretion systems: toward the development of non-pathogenic E. coli for in vivo delivery of therapeutic payloads.
er CF Abstract Transkingdom secretion systems that bacteria use to inject proteins directly into the cytosol of mammalian host cells play an essential role in the virulence of many Gram-negative bacterial pathogens. Current efforts are underway to repurpose these machines as novel therapeutics; type III secretion systems as vectors for the delivery of proteins of therapeutic value including heterologous antigens for vaccine development and type IV secretion systems as vectors for DNA. While initial studies focused on the use of attenuated or replication incompetent pathogens, the recent development of non-pathogen...
Source: Current Opinion in Microbiology - November 12, 2017 Category: Microbiology Authors: González-Prieto C, Lesser CF Tags: Curr Opin Microbiol Source Type: research

Exposing Toxoplasma gondii hiding inside the vacuole: a role for GBPs, autophagy and host cell death.
Abstract The intracellular parasite Toxoplasma gondii resides inside a vacuole, which shields it from the host's intracellular defense mechanisms. The cytokine interferon gamma (IFNγ) upregulates host cell effector pathways that are able to destroy the vacuole, restrict parasite growth and induce host cell death. Interferon-inducible GTPases such as the Guanylate Binding Proteins (GBPs), autophagy proteins and ubiquitin-driven mechanisms play important roles in Toxoplasma control in mice and partly also in humans. The host inflammasome is regulated by GBPs in response to bacterial infection in murine cells a...
Source: Current Opinion in Microbiology - November 12, 2017 Category: Microbiology Authors: Saeij JP, Frickel EM Tags: Curr Opin Microbiol Source Type: research

Host-microbe interactions: Malassezia and human skin.
Abstract The skin is our first line of defense, protecting us from invasion and evaporation. Its variable structure, changing geography, and complex immune repertoire provide a vast interface for our cutaneous microbial community. Skin is inhabited by many thousands of microbes, but this review focuses on the dominant eukaryote, Malassezia, and its host interaction. Malassezia compromises 17 species with variable niche specificities and differing pathogenic potential. It has been known as a skin inhabitant for over 100 years, and is now accepted to be on all warm-blooded animals. Malassezia occupy healthy and dise...
Source: Current Opinion in Microbiology - November 12, 2017 Category: Microbiology Authors: Grice EA, Dawson TL Tags: Curr Opin Microbiol Source Type: research

New advances in understanding the host immune response to Pneumocystis.
Abstract Pneumocystis jirovecii causes clinical pneumonia in immunocompromised hosts. Despite this, the inability to cultivate this organism in vitro has likely hindered the field in ascertaining the true impact of Pneumocystis in human infection. However the recent release of the genome as well as in advances in understanding host genetics, and other risk factors for infection and robust experimental models of disease have shed new light on the impact of this fungal pathogen as to better define populations at risk. This review will highlight these recent advances as well as highlight future needed areas of resear...
Source: Current Opinion in Microbiology - November 11, 2017 Category: Microbiology Authors: Hoving JC, Kolls JK Tags: Curr Opin Microbiol Source Type: research

Fungal interactions with the human host: exploring the spectrum of symbiosis.
Abstract Fungi are ubiquitous transient or persistent human colonisers, and form the mycobiome with shifts in niche specific mycobiomes (dysbiosis) being associated with various diseases. These complex interactions of fungal species with the human host can be viewed as a spectrum of symbiotic relationships (i.e. commensal, parasitic, mutualistic, amensalistic). The host relevant outcome of the relationship is the damage to benefit ratio, elegantly described in the damage response framework. This review focuses on Candida albicans, which is the most well studied human fungal symbiont clinically and experimentally, ...
Source: Current Opinion in Microbiology - November 10, 2017 Category: Microbiology Authors: Hall RA, Noverr MC Tags: Curr Opin Microbiol Source Type: research

Inborn errors of immunity underlying fungal diseases in otherwise healthy individuals.
Abstract It has been estimated that there are at least 1.5 million fungal species, mostly present in the environment, but only a few of these fungi cause human disease. Most fungal diseases are self-healing and benign, but some are chronic or life-threatening. Acquired and inherited defects of immunity, including breaches of mucocutaneous barriers and circulating leukocyte deficiencies, account for most severe modern-day mycoses. Other types of infection typically accompany these fungal infections. More rarely, severe fungal diseases can strike otherwise healthy individuals. Historical reports of fungi causing chr...
Source: Current Opinion in Microbiology - November 9, 2017 Category: Microbiology Authors: Li J, Vinh DC, Casanova JL, Puel A Tags: Curr Opin Microbiol Source Type: research