Iron uptake and virulence in Histoplasma capsulatum.
Abstract Histoplasma capsulatum (Hc) is the causative organism of a spectrum of disease affecting both the immunocompetent and the immunocompromised host. Hc is a dimporhic fungus that converts from conidia to the pathogenic yeast phase after entry into the mammalian host. Despite rapid ingestion by macrophages, it survives intracellularly within the macrophage. The intracellular survival strategy of Hc yeasts focuses on regulating the phagosomal compartment by modulating the intraphagosomal pH to 6.5. As an intracellular pathogen of MΦ, Hc obtains iron from Fe-transferrin, ferritin, or both, via the productio...
Source: Current Opinion in Microbiology - October 1, 2013 Category: Microbiology Authors: Newman SL, Smulian AG Tags: Curr Opin Microbiol Source Type: research

Prokaryotic cell division: flexible and diverse.
Abstract Gram-negative rod-shaped bacteria have different approaches to position the cell division initiating Z-ring at the correct moment in their cell division cycle. The subsequent maturation into a functional division machine occurs in vastly different species in two steps with appreciable time in between these. The function of this time delay is unclear, but may partly be explained by competition for Lipid-II between proteins involved in length growth that interact directly with the Z-ring early in the maturation phase and the proteins involved in septum synthesis. A second possible activity of the early Z-ri...
Source: Current Opinion in Microbiology - September 28, 2013 Category: Microbiology Authors: den Blaauwen T Tags: Curr Opin Microbiol Source Type: research

Iron in eukaryotic microbes: regulation, trafficking and theft.
PMID: 24074556 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - September 25, 2013 Category: Microbiology Authors: Kronstad JW Tags: Curr Opin Microbiol Source Type: research

Cytoskeletal proteins participate in conserved viral strategies across kingdoms of life.
Abstract The discovery of tubulin-like cytoskeletal proteins carried on the genomes of bacteriophages that are actively used for phage propagation during both the lytic and lysogenic cycle have revealed that there at least two ways that viruses can utilize a cytoskeleton; co-opt the host cytoskeleton or bring their own homologues. Either strategy underscores the deep evolutionary relationship between viruses and cytoskeletal proteins and points to a conservation of viral strategies that crosses the kingdoms of life. Here we review some of the most recent discoveries about tubulin cytoskeletal elements encoded by p...
Source: Current Opinion in Microbiology - September 19, 2013 Category: Microbiology Authors: Erb ML, Pogliano J Tags: Curr Opin Microbiol Source Type: research

The role of hydrolases in bacterial cell-wall growth.
Abstract Although hydrolysis is known to be as important as synthesis in the growth and development of the bacterial cell wall, the coupling between these processes is not well understood. Bond cleavage can generate deleterious pores, but may also be required for the incorporation of new material and for the expansion of the wall, highlighting the importance of mechanical forces in interpreting the consequences of hydrolysis in models of growth. Critically, minimal essential subsets of hydrolases have now been identified in several model organisms, enabling the reduction of genetic complexity. Recent studies in Ba...
Source: Current Opinion in Microbiology - September 12, 2013 Category: Microbiology Authors: Lee TK, Huang KC Tags: Curr Opin Microbiol Source Type: research

Establishing polar identity in gram-negative rods.
Abstract In rod shaped bacteria, numerous cellular components are targeted to the cell poles, and such localization is often important for optimal function. In particular, recognition of poles is often linked to division site selection, chromosome segregation, chemotactic signaling, and motility. Recent advances in understanding polarity include identification of a Vibrio cholerae protein that mediates polar localization of a chromosome origin and chemotaxis clusters, as well as a downstream protein that contributes solely to localization of chemotaxis proteins. In Caulobacter crescentus, the molecular mechanisms ...
Source: Current Opinion in Microbiology - September 9, 2013 Category: Microbiology Authors: Davis BM, Waldor MK Tags: Curr Opin Microbiol Source Type: research

The FUN of identifying gene function in bacterial pathogens; insights from Salmonella functional genomics.
JC Abstract The availability of thousands of genome sequences of bacterial pathogens poses a particular challenge because each genome contains hundreds of genes of unknown function (FUN). How can we easily discover which FUN genes encode important virulence factors? One solution is to combine two different functional genomic approaches. First, transcriptomics identifies bacterial FUN genes that show differential expression during the process of mammalian infection. Second, global mutagenesis identifies individual FUN genes that the pathogen requires to cause disease. The intersection of these datasets can reveal ...
Source: Current Opinion in Microbiology - September 7, 2013 Category: Microbiology Authors: Hammarlöf DL, Canals R, Hinton JC Tags: Curr Opin Microbiol Source Type: research

The phenomenon of microbial uncultivability.
Abstract Most of the microbial diversity on our planet cannot be cultivated, and remains inaccessible. To bring the missing species into culture, microbiologists have introduced over the past decade a number of innovations aiming to meet the demands of new microbes and better mimic their natural conditions. This resulted in a significant increase in microbial recovery yet the real reasons why so many microbes do not grow on artificial media remain largely unknown. The recently proposed scout model of microbial life cycle may provide a partial explanation for the phenomenon. It postulates that transition from dorma...
Source: Current Opinion in Microbiology - September 3, 2013 Category: Microbiology Authors: Epstein S Tags: Curr Opin Microbiol Source Type: research

New strategies and compounds for anti-infective treatment.
PMID: 23998895 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - August 30, 2013 Category: Microbiology Authors: Hancock RE, Sahl HG Tags: Curr Opin Microbiol Source Type: research

Coprophilous fungi: antibiotic discovery and functions in an underexplored arena of microbial defensive mutualism.
Abstract Microbial antibiotics can mediate mutualisms and interorganism communications. Herbivorous animal dung offers opportunities for discovery of new antibiotics from microbial communities that compete for a nutrient-rich, ephemeral resource. Distinct lineages form a specialized community of coprophilous (dung-colonizing) fungi. Bacteria, protists, invertebrates, the mammalian digestive system, and other fungi can pose challenges to their fitness in the dung environment. The well-characterized diversity of dung fungi offers accessible systems for dissecting the function of antibiotics and for exploring fungal ...
Source: Current Opinion in Microbiology - August 23, 2013 Category: Microbiology Authors: Bills GF, Gloer JB, An Z Tags: Curr Opin Microbiol Source Type: research

Pathways of iron acquisition and utilization in Leishmania.
Abstract Iron is essential for many metabolic pathways, but is toxic in excess. Recent identification of the ferric iron reductase LFR1, the ferrous iron transporter LIT1, and the heme transporter LHR1 greatly advanced our understanding of how Leishmania parasites acquire iron and regulate its uptake. LFR1 and LIT1 have close orthologs in plants, and are required for Leishmania virulence. Consistent with the lack of heme biosynthesis in trypanosomatids, LHR1 and LABCG5, a protein involved in heme salvage from hemoglobin, seem essential for Leishmania survival. LFR1, LIT1 and LHR1 are upregulated under low iron ava...
Source: Current Opinion in Microbiology - August 17, 2013 Category: Microbiology Authors: Flannery AR, Renberg RL, Andrews NW Tags: Curr Opin Microbiol Source Type: research

Iron sparing and recycling in a compartmentalized cell.
Abstract This review focuses on economizing, prioritizing and recycling iron in Chlamydomonas, a reference organism for discovering mechanisms of acclimation to poor iron nutrition in the plant lineage. The metabolic flexibility of Chlamydomonas offers a unique opportunity to distinguish the impact of iron nutrition on photosynthetic versus respiratory metabolism, and the contribution of subcellular compartments to iron storage and mobilization. Mechanisms of iron sparing include down regulation of protein abundance by transcript reduction or protein degradation. Two well-studied examples of hierarchical iron allo...
Source: Current Opinion in Microbiology - August 17, 2013 Category: Microbiology Authors: Blaby-Haas CE, Merchant SS Tags: Curr Opin Microbiol Source Type: research

Iron sensing and regulation in Saccharomyces cerevisiae: Ironing out the mechanistic details.
Abstract Regulation of iron metabolism in Saccharomyces cerevisiae is achieved at the transcriptional level by low (Aft1 and Aft2) and high iron-sensing (Yap5) transcription factors, and at the post-transcriptional level by mRNA-binding proteins (Cth1 and Cth2). In this review we highlight recent studies unveiling the critical role that iron-sulfur clusters play in control of Aft1/2 and Yap5 activity, as well as the complex relationship between iron homeostasis and thiol redox metabolism. In addition, new insights into the localization and regulation of Cth1/Cth2 have added another layer of complexity to the cell'...
Source: Current Opinion in Microbiology - August 17, 2013 Category: Microbiology Authors: Outten CE, Albetel AN Tags: Curr Opin Microbiol Source Type: research

The crucial role of iron uptake in Aspergillus fumigatus virulence.
Abstract Aspergillus fumigatus is an opportunistic fungal pathogen that causes life-threatening infections in immunocompromised individuals. Siderophore-mediated iron acquisition has been shown to be essential for virulence. New studies have revealed that enzymes involved in siderophore biosynthesis and uptake are compartmentalized in peroxisomes and endosome-like vesicles, respectively. Gene and protein expression studies have revealed coordinated regulation of siderophore and sterol metabolism linked to the common precursor mevalonate. Several A. fumigatus transcription factors have been identified that are unex...
Source: Current Opinion in Microbiology - August 17, 2013 Category: Microbiology Authors: Moore MM Tags: Curr Opin Microbiol Source Type: research

Progress in understanding fungal pathogenesis.
PMID: 23948072 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - August 12, 2013 Category: Microbiology Authors: Casadevall A Tags: Curr Opin Microbiol Source Type: research

Protein interaction networks as starting points to identify novel antimicrobial drug targets.
Abstract Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria. Current bacterial drug targets mainly consist of specific proteins or subsets of proteins without regard for either how these targets are integrated in cellular networks or how they may interact with host proteins. However, proteins rarely act in isolation, and the majority of biological processes are dependent on interactions with other proteins. Consequently, protein-protein interaction (PPI) networks offer a realm of unexplored potential for next-generation drug targets. In this review, we argue that th...
Source: Current Opinion in Microbiology - August 9, 2013 Category: Microbiology Authors: Zoraghi R, Reiner NE Tags: Curr Opin Microbiol Source Type: research

Bacterial cell division as a target for new antibiotics.
t H Abstract Bacterial resistance to currently applied antibiotics complicates the treatment of infections and demands the evaluation of new strategies to counteract multidrug-resistant bacteria. In recent years, the inhibition of the bacterial divisome, mainly by targeting the central cell division mediator FtsZ, has been recognized as a promising strategy for antibiotic attack. New antibiotics were shown to either interfere with the natural dynamics and functions of FtsZ during the cell cycle or to activate a bacterial protease to degrade FtsZ and thus bring about bacterial death in a suicidal manner. Their effi...
Source: Current Opinion in Microbiology - August 8, 2013 Category: Microbiology Authors: Sass P, Brötz-Oesterhelt H Tags: Curr Opin Microbiol Source Type: research

The asexual cycle of apicomplexan parasites: new findings that raise new questions.
PMID: 23932517 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - August 8, 2013 Category: Microbiology Authors: Meissner M Tags: Curr Opin Microbiol Source Type: research

Cryptic organelle homology in apicomplexan parasites: insights from evolutionary cell biology.
Abstract The economic and clinical significance of apicomplexan parasites drives interest in their many evolutionary novelties. Distinctive intracellular organelles play key roles in parasite motility, invasion, metabolism, and replication, and understanding their relationship with the organelles of better-studied eukaryotic systems suggests potential targets for therapeutic intervention. Recent work has demonstrated divergent aspects of canonical eukaryotic components in the Apicomplexa, including Golgi bodies and mitochondria. The apicoplast is a relict plastid of secondary endosymbiotic origin, harboring metabo...
Source: Current Opinion in Microbiology - August 7, 2013 Category: Microbiology Authors: Klinger CM, Nisbet RE, Ouologuem DT, Roos DS, Dacks JB Tags: Curr Opin Microbiol Source Type: research

Iron and heme metabolism in Plasmodium falciparum and the mechanism of action of artemisinins.
Abstract During the asexual blood stage of its lifecycle, the malaria parasite Plasmodium falciparum grows and multiplies in the hemoglobin-rich environment of the human erythrocyte. Although the parasite has evolved unique strategies to survive in this environment, its interaction with iron represents an Achilles' heel that is exploited by many antimalarial drugs. Recent work has shed new light on how the parasite deals with hemoglobin breakdown products and on the role of iron as a mediator of the action of the antimalarial drug, artemisinin. PMID: 23932203 [PubMed - as supplied by publisher] (Source: Curre...
Source: Current Opinion in Microbiology - August 7, 2013 Category: Microbiology Authors: Klonis N, Creek DJ, Tilley L Tags: Curr Opin Microbiol Source Type: research

Organelle transcriptomes: products of a deconstructed genome.
Abstract Genetic drift and mutational pressure have shaped the evolution of mitochondrial and chloroplast genomes, giving rise to mechanisms that regulate their gene expression, which often differ from those in their prokaryotic ancestors. Advances in next generation sequencing technologies have enabled highly detailed characterization of organelle transcriptomes and the discovery of new transcripts and mechanisms for controlling gene expression. Here we discuss the common features of organelle transcriptomes that stem from their prokaryotic origin and some of the new innovations that are unique to organelles of m...
Source: Current Opinion in Microbiology - August 7, 2013 Category: Microbiology Authors: Small ID, Rackham O, Filipovska A Tags: Curr Opin Microbiol Source Type: research

The metabolic roles of the endosymbiotic organelles of Toxoplasma and Plasmodium spp.
Abstract The apicoplast and the mitochondrion of Apicomplexa cooperate in providing essential metabolites. Their co-evolution during the ancestral acquisition of a plastid and subsequent loss of photosynthesis resulted in divergent metabolic pathways compared with mammals and plants. This is most evident in their chimerical haem synthesis pathway. Toxoplasma and Plasmodium mitochondria operate canonical tricarboxylic acid (TCA) cycles and electron transport chains, although the roles differ between Toxoplasma tachyzoites and Plasmodium erythrocytic stages. Glutamine catabolism provides TCA intermediates in both pa...
Source: Current Opinion in Microbiology - August 5, 2013 Category: Microbiology Authors: Sheiner L, Vaidya AB, McFadden GI Tags: Curr Opin Microbiol Source Type: research

Iron acquisition in the human fungal pathogen Cryptococcus neoformans.
Abstract Iron sequestration by the vertebrate host is considered an efficient defense mechanism against pathogenic microbes. However, this mechanism, so called nutritional immunity, is often overcome by the iron acquisition systems that have evolved in microbial pathogens. Numerous studies have been carried out to identify the key components of these systems and to understand their underlying mechanisms, including recent investigations in the basidiomycete fungal pathogen Cryptococcus neoformans. Iron acquisition is essential for the survival and pathogenesis of this fungus within vertebrate hosts. Growing evidenc...
Source: Current Opinion in Microbiology - August 5, 2013 Category: Microbiology Authors: Jung WH, Do E Tags: Curr Opin Microbiol Source Type: research

Virus diversity and evolution.
PMID: 23927896 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - August 5, 2013 Category: Microbiology Authors: Arias CF Tags: Curr Opin Microbiol Source Type: research

Iron uptake and regulation in Schizosaccharomyces pombe.
es JF Abstract Schizosaccharomyces pombe is a useful model system for understanding many aspects of eukaryotic cell growth. Studies of S. pombe have identified novel genes that function in the regulation of iron homeostasis. In response to high levels of iron, Fep1 represses the expression of several genes involved in the acquisition of iron. When iron levels are limited, optimization of cellular iron utilization is coordinated by Php4, which represses genes encoding iron-using proteins. Results from studies in yeast have shed new light on the role of monothiol glutaredoxins (Grxs) in iron homeostasis. In S. pombe...
Source: Current Opinion in Microbiology - August 2, 2013 Category: Microbiology Authors: Labbé S, Khan MG, Jacques JF Tags: Curr Opin Microbiol Source Type: research

Teichoic acid biosynthesis as an antibiotic target.
Abstract The relentless spread of antibiotic-resistant pathogens makes it imperative to develop new chemotherapeutic strategies to overcome infection. The bacterial cell wall has served as a rich source for both validated and unexploited pathways that are essential for virulence and survival. Lipoteichoic acids (LTAs) and wall teichoic acids (WTAs) are cell wall polymers that play fundamental roles in Gram-positive bacterial physiology and pathogenesis, and both have been proposed as novel antibacterial targets. Here we describe recent progress toward the discovery of teichoic acid biosynthesis inhibitors and thei...
Source: Current Opinion in Microbiology - July 31, 2013 Category: Microbiology Authors: Pasquina LW, Santa Maria JP, Walker S Tags: Curr Opin Microbiol Source Type: research

Ecology and industrial microbiology.
PMID: 23910626 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - July 30, 2013 Category: Microbiology Authors: Wells JM, Langella P Tags: Curr Opin Microbiol Source Type: research

Auxiliary factors: a chink in the armor of MRSA resistance to β-lactam antibiotics.
Auxiliary factors: a chink in the armor of MRSA resistance to β-lactam antibiotics. Curr Opin Microbiol. 2013 Jul 26; Authors: Roemer T, Schneider T, Pinho MG Abstract Combination agents provide an important orthogonal approach to treat infectious diseases, particularly those caused by drug resistant pathogens. Indeed, applying a biologically 'rational' and systems-level paradigm to discover potent, selective, and synergistic agents would augment current (and arguably overly relied upon) empirical and serendipitous approaches to such discovery efforts. Here, we review the cellular mechanisms of β...
Source: Current Opinion in Microbiology - July 26, 2013 Category: Microbiology Authors: Roemer T, Schneider T, Pinho MG Tags: Curr Opin Microbiol Source Type: research

Key molecular events during host cell invasion by Apicomplexan pathogens.
Abstract The ability of Apicomplexan parasites to invade host cells is key to their survival and pathogenesis. Plasmodium and Toxoplasma parasites share common mechanisms for invasion of host cells. Secretion of microneme and rhoptry proteins, tight junction formation and assembly of an acto-myosin motor are key steps for successful invasion by both parasites. Here, we review our understanding of the molecular basis for these steps. PMID: 23895827 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - July 26, 2013 Category: Microbiology Authors: Sharma P, Chitnis CE Tags: Curr Opin Microbiol Source Type: research

Omics approaches to study host-microbiota interactions.
Abstract The intestinal microbiota has profound effects on our physiology and immune system and disturbances in the equilibrium between microbiota and host have been observed in many disorders. Here we discuss the possibilities to further our understanding of how microbiota impacts on human health and disease through the use of large-scale quantifiable tools such as transcriptomics, metagenomics and metabolomics. Reductionist models, including gnotobiotic mouse models have their place in testing hypotheses and elucidating mechanisms by which specific communities or individual species impact on host biology. Networ...
Source: Current Opinion in Microbiology - July 23, 2013 Category: Microbiology Authors: van Baarlen P, Kleerebezem M, Wells JM Tags: Curr Opin Microbiol Source Type: research

Colonic bacterial metabolites and human health.
Abstract The influence of the microbial-mammalian metabolic axis is becoming increasingly important for human health. Bacterial fermentation of carbohydrates (CHOs) and proteins produces short-chain fatty acids (SCFA) and a range of other metabolites including those from aromatic amino acid (AAA) fermentation. SCFA influence host health as energy sources and via multiple signalling mechanisms. Bacterial transformation of fibre-related phytochemicals is associated with a reduced incidence of several chronic diseases. The 'gut-liver axis' is an emerging area of study. Microbial deconjugation of xenobiotics and relea...
Source: Current Opinion in Microbiology - July 20, 2013 Category: Microbiology Authors: Russell WR, Hoyles L, Flint HJ, Dumas ME Tags: Curr Opin Microbiol Source Type: research

Bacterial biofilm development as a multicellular adaptation: antibiotic resistance and new therapeutic strategies.
dez L, Hancock RE Abstract Bacteria have evolved the ability to form multicellular, surface-adherent communities called biofilms that allow survival in hostile environments. In clinical settings, bacteria are exposed to various sources of stress, including antibiotics, nutrient limitation, anaerobiosis, heat shock, etc., which in turn trigger adaptive responses in bacterial cells. The combination of this and other defense mechanisms results in the formation of highly (adaptively) resistant multicellular structures that are recalcitrant to host immune clearance mechanisms and very difficult to eradicate with the cu...
Source: Current Opinion in Microbiology - July 20, 2013 Category: Microbiology Authors: de la Fuente-Núñez C, Reffuveille F, Fernández L, Hancock RE Tags: Curr Opin Microbiol Source Type: research

Innate immunity, the constant gardener of antimicrobial defense.
PMID: 23880137 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - July 20, 2013 Category: Microbiology Authors: Schroder K, Deretic V Tags: Curr Opin Microbiol Source Type: research

PK/PD models in antibacterial development.
Abstract There is an urgent need for novel antibiotics to treat life-threatening infections caused by bacterial 'superbugs'. Validated in vitro pharmacokinetic/pharmacodynamic (PK/PD) and animal infection models have been employed to identify the most predictive PK/PD indices and serve as key tools in the antibiotic development process. The results obtained can be utilized for optimizing study designs in order to minimize the cost and duration of clinical trials. This review outlines the key in vitro PK/PD and animal infection models which have been extensively used in antibiotic discovery and development. These m...
Source: Current Opinion in Microbiology - July 18, 2013 Category: Microbiology Authors: Velkov T, Bergen PJ, Lora-Tamayo J, Landersdorfer CB, Li J Tags: Curr Opin Microbiol Source Type: research

Immunomodulatory approaches for prevention and treatment of infectious diseases.
Abstract With increasing pathogen resistance to antibiotics, population ageing, and threat of pandemics there is a strong interest in the development of new approaches for the treatment of infectious diseases. Immunomodulatory therapies are defined as interventions that target the host rather than the pathogen, modulating the immune response with the aim of disease prevention or treatment. Our growing understanding of the immune system continues to offer novel drug targets and approaches for immunomodulatory interventions. In this review we will cover prominent examples of immunomodulatory therapies already in cli...
Source: Current Opinion in Microbiology - July 17, 2013 Category: Microbiology Authors: Nijnik A Tags: Curr Opin Microbiol Source Type: research

Human intestinal metagenomics: state of the art and future.
ré J Abstract Over the last few years our understanding of human biology has undergone profound transformation. The key role of the 'world inside us', namely the gut microbiota, once considered a forgotten organ, has been revealed, with strong impact on our health and well-being. The present review highlights the most important recent findings on the role of gut microbiota and its impact on the host and raises crucial questions to be considered in future studies. PMID: 23870802 [PubMed - as supplied by publisher] (Source: Current Opinion in Microbiology)
Source: Current Opinion in Microbiology - July 16, 2013 Category: Microbiology Authors: Blottière HM, de Vos WM, Ehrlich SD, Doré J Tags: Curr Opin Microbiol Source Type: research

Probiotics from research to market: the possibilities, risks and challenges.
Pot B Abstract Probiotic foods can affect large parts of the population, while therapeutic applications have a less wide scope. While commercialization routes and regulatory requirements differ for both applications, both will need good scientific support. Today, probiotics are mainly used for gastrointestinal applications, their use can easily be extended to skin, oral and vaginal health. While most probiotics currently belong to food-grade species, the future may offer new functional microorganisms in food and pharma. This review discusses the crosstalk between probiotic producers, regulatory people, medical car...
Source: Current Opinion in Microbiology - July 15, 2013 Category: Microbiology Authors: Foligné B, Daniel C, Pot B Tags: Curr Opin Microbiol Source Type: research

Bacteriotherapy for the treatment of intestinal dysbiosis caused by Clostridium difficile infection.
Abstract Faecal microbiota transplantation (FMT) has been used for more than five decades to treat a variety of intestinal diseases associated with pathological imbalances within the resident microbiota, termed dysbiosis. FMT has been particularly effective for treating patients with recurrent Clostridium difficile infection who are left with few clinical options other than continued antibiotic therapy. Our increasing knowledge of the structure and function of the human intestinal microbiota and C. difficile pathogenesis has led to the understanding that FMT promotes intestinal ecological restoration and highlight...
Source: Current Opinion in Microbiology - July 15, 2013 Category: Microbiology Authors: Adamu BO, Lawley TD Tags: Curr Opin Microbiol Source Type: research

Engineering lactococci and lactobacilli for human health.
Langella P Abstract Food-grade lactic acid bacteria (LAB) are good candidates for the development of oral vectors, and are attractive alternatives to attenuated pathogens, for mucosal delivery strategies. In this review, we summarize recent results on the use of LAB as mucosal delivery vectors for therapeutic proteins and DNA vaccines. Most of this work has been based on the model LAB, Lactococcus lactis, which is suitable for the heterologous expression of therapeutic proteins. Recombinant lactococci and lactobacilli strains expressing antiproteases and antioxidant enzymes have been tested successfully for their...
Source: Current Opinion in Microbiology - July 11, 2013 Category: Microbiology Authors: Bermúdez-Humarán LG, Aubry C, Motta JP, Deraison C, Steidler L, Vergnolle N, Chatel JM, Langella P Tags: Curr Opin Microbiol Source Type: research

Virus discovery and recent insights into virus diversity in arthropods.
Abstract Recent studies on virus discovery have focused mainly on mammalian and avian viruses. Arbovirology with its long tradition of ecologically oriented investigation is now catching up, with important novel insights into the diversity of arthropod-associated viruses. Recent discoveries include taxonomically outlying viruses within the families Flaviviridae, Togaviridae, and Bunyaviridae, and even novel virus families within the order Nidovirales. However, the current focusing of studies on blood-feeding arthropods has restricted the range of arthropod hosts analyzed for viruses so far. Future investigations s...
Source: Current Opinion in Microbiology - July 11, 2013 Category: Microbiology Authors: Junglen S, Drosten C Tags: Curr Opin Microbiol Source Type: research

The adoptive transfer of behavioral phenotype via the intestinal microbiota: experimental evidence and clinical implications.
Abstract There is growing interest in the ability of the intestinal microbiome to influence host function within and beyond the gastrointestinal tract. Here we review evidence of microbiome-brain interactions in mice and focus on the ability to transfer behavioral traits between mouse strains using fecal microbiota transplantation (FMT). Transplantation alters brain chemistry and behavior in recipient ex-germ free mice, raising the possibility of using FMT for disorders of the central nervous system, and prompting caution in the selection of FMT donors for conditions that may include refractory Clostridium diffici...
Source: Current Opinion in Microbiology - July 8, 2013 Category: Microbiology Authors: Collins SM, Kassam Z, Bercik P Tags: Curr Opin Microbiol Source Type: research

Faecalibacterium prausnitzii and human intestinal health.
lls J, Langella P Abstract Faecalibacterium prausnitzii is the most abundant bacterium in the human intestinal microbiota of healthy adults, representing more than 5% of the total bacterial population. Over the past five years, an increasing number of studies have clearly described the importance of this highly metabolically active commensal bacterium as a component of the healthy human microbiota. Changes in the abundance of F. prausnitzii have been linked to dysbiosis in several human disorders. Administration of F. prausnitzii strain A2-165 and its culture supernatant have been shown to protect against 2,4,6-tr...
Source: Current Opinion in Microbiology - July 3, 2013 Category: Microbiology Authors: Miquel S, Martín R, Rossi O, Bermúdez-Humarán L, Chatel J, Sokol H, Thomas M, Wells J, Langella P Tags: Curr Opin Microbiol Source Type: research

Cell surface-associated compounds of probiotic lactobacilli sustain the strain-specificity dogma.
Abstract Probiotic lactobacilli can positively impact on the health status of targeted (diseased) populations but efficacy depends strongly on the strain employed and the molecular basis for this phenomenon is poorly understood. This review discusses the current state-of-the-art in the field of molecular probiotic-host interactions, focusing on subtle strain-specific differences in the biochemical characteristics of cell surface-associated probiotic ligands and the consequences thereof for the immune responses elicited. This research is bound to enhance our understanding of strain-specificity in relation to probio...
Source: Current Opinion in Microbiology - June 28, 2013 Category: Microbiology Authors: Bron PA, Tomita S, Mercenier A, Kleerebezem M Tags: Curr Opin Microbiol Source Type: research

A life history view of mutualistic viral symbioses: quantity or quality for cooperation?
Abstract Mutualistic symbioses between viruses and their hosts do not employ a straightforward rule by viral genome characteristics, transmission mechanisms or host genotypes. In this review we propose that reproduction rates and environmental carrying capacity of hosts may play a major role in maintaining the mutualism. Depending on how host life history shifts following establishment of the symbiosis, a symbiosis can be classified as quality-selected mutualism or quantity-selected mutualism. Quality-selected mutualism is described with modified Lotka-Volterra models. Both our models and previous empirical exampl...
Source: Current Opinion in Microbiology - June 21, 2013 Category: Microbiology Authors: Bao X, Roossinck MJ Tags: Curr Opin Microbiol Source Type: research

Autophagy as an immune effector against tuberculosis.
Abstract The now well-accepted innate immunity paradigm that autophagy acts as a cell-autonomous defense against intracellular bacteria has its key origins in studies with Mycobacterium tuberculosis, an important human pathogen and a model microorganism infecting macrophages. A number of different factors have been identified that play into the anti-mycobacterial functions of autophagy, and recent in vivo studies in the mouse model of tuberculosis have uncovered additional anti-inflammatory and tissue-sparing functions of autophagy. Complementing these observations, genome wide association studies indicate a consi...
Source: Current Opinion in Microbiology - June 18, 2013 Category: Microbiology Authors: Bradfute SB, Castillo EF, Arko-Mensah J, Chauhan S, Jiang S, Mandell M, Deretic V Tags: Curr Opin Microbiol Source Type: research

Mitochondria: sensors and mediators of innate immune receptor signaling.
Abstract By integrating stress signals with inputs from other cellular organelles, eukaryotic mitochondria are dynamic sensing systems that can confer substantial impact on innate immune signaling in both health and disease. This review highlights recently discovered elements of innate immune receptor signaling (TLR, RLR, NLR, and CLR) associated with mitochondrial function and discusses the role of mitochondria in the initiation and/or manifestation of inflammatory diseases and disorders. We also highlight the role of mitochondria as therapeutic targets for inflammatory disease. PMID: 23757367 [PubMed - as s...
Source: Current Opinion in Microbiology - June 8, 2013 Category: Microbiology Authors: Cloonan SM, Choi AM Tags: Curr Opin Microbiol Source Type: research

Inhibition of human immunodeficiency virus type-1 through autophagy.
Abstract As an obligatory intracellular pathogen, human immunodeficiency virus type-1 (HIV) is dependent upon its ability to exploit host cell machinery for replication and dissemination, and to circumvent cellular processes that prevent its growth. One such intracellular process is autophagy, a component of the host defense against HIV with roles in innate immune signaling, adaptive immunity and intracellular degradation of HIV. During permissive infection, HIV down-modulates autophagy, promoting its own replication. Inducers of autophagy can overcome this suppression and inhibit HIV. This review summarizes recen...
Source: Current Opinion in Microbiology - June 5, 2013 Category: Microbiology Authors: Campbell GR, Spector SA Tags: Curr Opin Microbiol Source Type: research

Striking a balance: fungal commensalism versus pathogenesis.
Abstract The environment is suffused with nearly countless types of fungi, and our immune systems must be tuned to cope with constant exposure to them. In addition, it is becoming increasingly clear that many surfaces of our bodies are colonized with complex populations of fungi (the mycobiome) in the same way that they are colonized with complex populations of bacteria. The immune system must tolerate colonization with commensal fungi but defend against fungal invasion. Truly life-threatening fungal infections are common only when this balance is disrupted through, for example, profound immunosuppression or genet...
Source: Current Opinion in Microbiology - June 4, 2013 Category: Microbiology Authors: Iliev ID, Underhill DM Tags: Curr Opin Microbiol Source Type: research

Invasion factors of apicomplexan parasites: essential or redundant?
Abstract Apicomplexa are obligate intracellular parasites that cause several human and veterinary diseases worldwide. In contrast to most intracellular pathogens these protozoans are believed to invade a rather passive host cell in a process, that is, tightly linked to the ability of the parasites to move by gliding motility. Indeed specific inhibitors against components of the gliding machinery and the analysis of knockdown mutants demonstrate a linkage of gliding motility and invasion. Intriguingly, new data show that it is possible to block gliding motility, while host cell invasion still occurs. This suggests ...
Source: Current Opinion in Microbiology - May 30, 2013 Category: Microbiology Authors: Meissner M, Ferguson DJ, Frischknecht F Tags: Curr Opin Microbiol Source Type: research

Bacteriophage-host interaction: from splendid isolation into a messy reality.
w H Abstract In the reductionist era T-type coliphage research became one of the foundations for molecular biology. The technological progress in systems biology makes it now possible to study T-type phage-Escherichia coli interaction in the natural ecological niche, the gut of warm blooded animals. This development gives a second chance to phages as anti-microbial agents ('phage therapy'). Bacteria growing in biofilms are difficult to treat with antibiotics while many phages express naturally depolymerases which attack the polysaccharide matrix that enmesh bacteria in biofilms. Phages were already used successful...
Source: Current Opinion in Microbiology - May 28, 2013 Category: Microbiology Authors: Brüssow H Tags: Curr Opin Microbiol Source Type: research