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Microbial symbiosis of marine sessile hosts - Diversity and function

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196814 Year: Pages: 108 DOI: 10.3389/978-2-88919-681-4 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2016-04-07 11:22:02
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Modern molecular -omics tools (metagenomics, metaproteomics etc.) have greatly contributed to the rapid advancement of our understanding of microbial diversity and function in the world’s oceans. These tools are now increasingly applied to host-associated environments to describe the symbiotic microbiome and obtain a holistic view of marine host-microbial interactions. Whilst all eukaryotic hosts are likely to benefit from their microbial associates, marine sessile eukaryotes, including macroalgae, seagrasses and various invertebrates (sponges, acidians, corals, hydroids etc), rely in particular on the function of their microbiome. For example, marine sessile eukaryotes are under constant grazing, colonization and fouling pressure from the millions of micro- and macroorganisms in the surrounding seawater. Host-associated microorganisms have been shown to produce secondary metabolites as defense molecules against unwanted colonization or pathogens, thus having an important function in host health and survival. Similarly microbial symbionts of sessile eukaryotes are often essential players in local nutrient cycling thus benefiting both the host and the surrounding ecosystem. Various research fields have contributed to generating knowledge of host-associated systems, including microbiology, biotechnology, molecular biology, ecology, evolution and biotechnology. Through a focus on model marine sessile host systems we believe that new insight into the interactions between host and microbial symbionts will be obtained and important areas of future research will be identified. This research topic includes original research, review and opinion articles that bring together the knowledge from different aspects of biology and highlight advances in our understanding of the diversity and function of the microbiomes on marine sessile hosts.

Microbial responses to environmental changes

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197231 Year: Pages: 261 DOI: 10.3389/978-2-88919-723-1 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2016-04-07 11:22:02
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Advances in next generation sequencing technologies, omics, and bioinformatics are revealing a tremendous and unsuspected diversity of microbes, both at a compositional and functional level. Moreover, the expansion of ecological concepts into microbial ecology has greatly advanced our comprehension of the role microbes play in the functioning of ecosystems across a wide range of biomes. Super-imposed on this new information about microbes, their functions and how they are organized, environmental gradients are changing rapidly, largely driven by direct and indirect human activities. In the context of global change, understanding the mechanisms that shape microbial communities is pivotal to predict microbial responses to novel selective forces and their implications at the local as well as global scale. One of the main features of microbial communities is their ability to react to changes in the environment. Thus, many studies have reported changes in the performance and composition of communities along environmental gradients. However, the mechanisms underlying these responses remain unclear. It is assumed that the response of microbes to changes in the environment is mediated by a complex combination of shifts in the physiological properties, single-cell activities, or composition of communities: it may occur by means of physiological adjustments of the taxa present in a community or selecting towards more tolerant/better adapted phylotypes. Knowing whether certain factors trigger one, many, or all mechanisms would greatly increase confidence in predictions of future microbial composition and processes. This Research Topic brings together studies that applied the latest molecular techniques for studying microbial composition and functioning and integrated ecological, biogeochemical and/or modeling approaches to provide a comprehensive and mechanistic perspective of the responses of micro-organisms to environmental changes. This Research Topic presents new findings on environmental parameters influencing microbial communities, the type and magnitude of response and differences in the response among microbial groups, and which collectively deepen our current understanding and knowledge of the underlying mechanisms of microbial structural and functional responses to environmental changes and gradients in both aquatic and terrestrial ecosystems. The body of work has, furthermore, identified many challenges and questions that yet remain to be addressed and new perspectives to follow up on.

Microbiota of Grapes: Positive and Negative Role on Wine Quality

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451210 Year: Pages: 231 DOI: 10.3389/978-2-88945-121-0 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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During spontaneous food/beverage fermentations, the microbiota associated with the raw material has a considerable importance: this microbial consortium evolves in reason of the nutrient content and of the physical, chemical, and biological determinants present in the food matrix, shaping fermentation dynamics with significant impacts on the ‘qualities’ of final productions. The selection from the indigenous micro-biodiversity of ‘virtuous’ ecotypes that coupled pro-technological and biotechnological aptitudes provide the basis for the formulation of ‘tailored’ starter cultures. In the fermenting food and beverage arena, the wine sector is generally characterized by the generation of a high added value. Together with a pronounced seasonality, this feature strongly contributes to the selection of a large group of starter cultures. In the last years, several studies contributed to describe the complexity of grapevine-associated microbiota using both culture-dependent and culture-independent approaches. The grape-associated microbial communities continuously change during the wine-making process, with different dominances that correspond to the main biotechnological steps that take place in wine. In order to simplify, following a time trend, four major dominances can be mainly considered: non-Saccharomyces, Saccharomyces, lactic acid bacteria (LAB), and spoilage microbes. The first two dominances come in succession during the alcoholic fermentation: the impact of Saccharomyces (that are responsible of key enological step of ethanol production) can be complemented/integrated by the contributions of compatible non-Saccharomyces strains. Lactic acid bacteria constitute the malolactic consortium responsible of malolactic fermentation, a microbial bioconversion often desired in wine (especially in red wine production). Finally, the fourth dominance, the undesired microbiota, represents a panel of microorganisms that, coupling spoilage potential to the resistance to the harsh conditions typical of wine environment, can cause important economic losses. In each of these four dominances a complex microbial biodiversity has been described. The studies on the enological significance of the micro-biodiversity connected with each of the four dominances highlighted the presence of a dichotomy: in each consortia there are species/strains that, in reason of their metabolisms, are able to improve wine ‘qualities’ (resource of interest in starter cultures design), and species/strains that with their metabolism are responsible of depreciation of wine. Articles describing new oenological impacts of yeasts and bacteria belonging to the four main categories above mentioned (non-Saccharomyces, Saccharomycetes, lactic acid bacteria, and spoilage microbes) are welcome. Moreover, in this Research Topic, we encourage mini-review submissions on topics of immediate interest in wine microbiology that link microbial biodiversity with positive/negative effects in wine.

Molecular Ecology and Genetic Diversity of the Roseobacter Clade

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455386 Year: Pages: 138 DOI: 10.3389/978-2-88945-538-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology
Added to DOAB on : 2019-01-23 14:53:42
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Marine bacteria and archaea are key players in the biogeochemical cycling of nitrogen, carbon, and other elements. One important lineage of marine bacteria is the Roseobacter group. Members of this clade are the most abundant bacteria in marine ecosystems constituting up to 25% of the marine bacterioplankton. They have been detected in various marine habitats from coastal regions to deep-sea sediments and from polar regions to tropical latitudes. These bacteria are physiologically and genetically very versatile. Utilization of several organic and inorganic compounds, sulfur oxidation, aerobic anoxygenic photosynthesis, carbon monoxide oxidation, DMSP demethylation, and production of secondary metabolites are some of the important functional traits found in this clade. Moreover, several isolates are available allowing in-depth analysis of physiological and genetic characteristics. Although the Roseobacter group has been intensively studied in recent years, our understanding of its ecological contributions and the evolutionary processes shaping the genomes of this clade is still rather limited.

Effects of Mycotoxins on the Intestine

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ISBN: 9783038977827 9783038977834 Year: Pages: 262 DOI: 10.3390/books978-3-03897-783-4 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Public Health
Added to DOAB on : 2019-05-09 17:16:14
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Mycotoxins are secondary metabolites produced by several fungal species. They can contaminate human food and animal feed, and have been a threat for thousands of years. The gastrointestinal tract is the first target when ingesting mycotoxin-contaminated food or feed. As unlikely as it sounds, the investigations concerning the effects of mycotoxins on the intestine are still in their early stages. This book gathers the most recent advances related to the characterization of the intestinal toxicity of mycotoxins. Substantial data assembled on the damage caused to a number of histological structures and functions of the intestine remove any remaining doubt about this organ being a primary target for the toxicity of mycotoxins. An interesting overview of the detrimental effects of mycotoxins on the gut-hosted microbiota—now regarded as a fully-fledged organ associated with the gut—is also given. Finally, outstanding contributions in this book address questions relating to the suitability of current regulations to protect against alterations of the intestine, and to the efficacy assessment of new detoxification strategies using the intestinal toxicity of mycotoxins as a relevant endpoint.

Keywords

mice --- aflatoxin B1 --- intestinal bacterial flora --- response --- Clostridium sp. WJ06 --- deoxynivalenol --- pig --- intestinal morphology --- microbial diversity --- aflatoxin M1 --- ochratoxin A --- intestinal epithelial cells --- tight junction --- permeability --- ileum --- jejunum --- deoxynivalenol --- piglet --- contaminated feed --- tight junction --- aflatoxin B1 --- small intestine --- histopathological lesions --- ultrastructural changes --- toll-like receptors --- T-2 toxin --- enteric nervous system --- pig --- vasoactive intestinal polypeptide --- mycotoxins --- zearalenone --- deoxynivalenol --- histology --- ultrastructure --- large intestine --- pig --- Claviceps --- liver --- digestive tract --- mycotoxin --- sclerotia --- ergot alkaloids --- toxicity --- deoxynivalenol --- Saccharomyces cerevisiae boulardii CNCM I-1079 --- intestine --- transcriptome --- inflammation --- oxidative stress --- lipid metabolism --- fumonisin --- microbiota --- pigs --- MiSeq 16S rDNA sequencing --- intestinal microbiota --- hydrogen-rich water --- lactulose --- Fusarium mycotoxins --- piglets --- functional oligosaccharides --- mycotoxins --- swine --- explant technique --- intestinal morphology --- goblet cells --- deoxynivalenol --- zearalenone --- pig --- colon microbiota --- Lactobacillus --- detoxification --- zearalenone --- doses --- caecal water --- genotoxicity --- pre-pubertal gilts --- atlantic salmon --- deoxynivalenol --- feed --- intestine --- PCR --- proliferating cell nuclear antigen --- suppressor of cytokine signaling --- tight junctions --- Zearalenone --- N-acetylcysteine --- SIEC02 cells --- Mitochondrial apoptosis --- n/a

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