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Metabolic Interactions Between Bacteria and Phytoplankton

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454952 Year: Pages: 227 DOI: 10.3389/978-2-88945-495-2 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology --- Oceanography
Added to DOAB on : 2019-01-23 14:53:42
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The cycling of energy and elements in aquatic environments is controlled by the interaction of autotrophic and heterotrophic processes. In surface waters of lakes, rivers, and oceans, photosynthetic microalgae and cyanobacteria fix carbon dioxide into organic matter that is then metabolized by heterotrophic bacteria (and perhaps archaea). Nutrients are remineralized by heterotrophic processes and subsequently enable phototrophs to grow. The organisms that comprise these two major ecological guilds are numerous in both numbers and in their genetic diversity, leading to a vast array of physiological and chemical responses to their environment and to each other. Interactions between bacteria and phytoplankton range from obligate to facultative, as well as from mutualistic to parasitic, and can be mediated by cell-to-cell attachment or through the release of chemicals. The contributions to this Research Topic investigate direct or indirect interactions between bacteria and phytoplankton using chemical, physiological, and/or genetic approaches. Topics include nutrient and vitamin acquisition, algal pathogenesis, microbial community structure during algal blooms or in algal aquaculture ponds, cell-cell interactions, chemical exudation, signaling molecules, and nitrogen exchange. These studies span true symbiosis where the interaction is evolutionarily derived, as well as those of indirect interactions such as bacterial incorporation of phytoplankton-produced organic matter and man-made synthetic symbiosis/synthetic mutualism.

Keywords

bacteria --- algae --- algicidal --- mutualism

LuxR Solos are Becoming Major Players in Cell-Cell Communication in Bacteria

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199174 Year: Pages: 122 DOI: 10.3389/978-2-88919-917-4 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Biology
Added to DOAB on : 2016-01-19 14:05:46
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The most common quorum sensing (QS) system in Gram-negative bacteria occurs via N-acyl homoserine lactone (AHLs) signals. An archetypical system consists of a LuxI-family protein synthesizing the AHL signal which binds at quorum concentrations to the cognate LuxR-family transcription factors which then control gene expression by binding to specific sequences in target gene promoters. QS LuxR-family proteins are approximately 250 amino acids long and made up of two domains; at the N-terminus there is an autoinducer-binding domain whereas the C-terminus contains a DNA-binding helix-turn-helix (HTH) domain. QS LuxRs display surprisingly low similarities (18-25%) even if they respond to structurally similar AHLs. 95% of LuxRs share 9 highly conserved amino acid residues; six of these are hydrophobic or aromatic and form the cavity of the AHL-binding domain and the remaining three are in the HTH domain. With only very few exceptions, the luxI/R cognate genes of AHL QS systems are located adjacent to each other. The sequencing of many bacterial genomes has revealed that many proteobacteria also possess LuxRs that do not have a cognate LuxI protein associated with them. These LuxRs have been called orphans and more recently solos. LuxR solos are widespread in proteobacterial species that possess a canonical complete AHL QS system as well as in species that do not. In many cases more than one LuxR solo is present in a bacterial genome. Scientists are beginning to investigate these solos. Are solos responding to AHL signals? If present in a bacterium which possesses a canonical AHL QS system are solos an integral part of the regulatory circuit? Are LuxR solos eavesdropping on AHLs produced by neighboring bacteria? Have they evolved to respond to different signals instead of AHLs, and are these signals endogenously produced or exogenously provided? Are they involved in interkingdom signaling by responding to eukaryotic signals? Recent studies have revealed that LuxR solos are involved in several mechanisms of cell-cell communication in bacteria implicating them in bacterial intraspecies and interspecies communication as well as in interkingdom signaling by responding to molecules produced by eukaryotes. LuxR solos are likely to become major players in signaling since they are widespread among proteobacterial genomes and because initial studies highlight their different roles in bacterial communication. This Research Topic allows scientists studying or interested in LuxR solos to report their data and/or express their hypotheses and thoughts on this important and currently understudied family of signaling proteins.

Keywords

AHL --- LuxR solos --- Quorum Sensing --- signaling --- Bacteria

Surgical Infections

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454983 Year: Pages: 47 DOI: 10.3389/978-2-88945-498-3 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Surgery
Added to DOAB on : 2019-01-23 14:53:42
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Surgical infections are caused by the breakdown of the equilibrium existing between organisms and the host. This may occur after a breach in a protective surface, as occurs after surgical trauma, changes in host resistance, or particular characteristics of the organism. The possible outcomes are abscess formation, local spread with/without tissue death, distant spread or resolution. A surgical infection is an infection requiring operative treatment (excision or drainage), and occupies an unvascularized space in tissue, or may occur in an operated site. Common examples of the former group are furuncles and carbuncles, hollow viscus inflammations, such as appendicitis, cholecystitis, and most abscesses. The latter group comprises all surgical site infections.This Research Topic provides comprehensive information on the biology, mechanisms, prevention and treatment of surgery-related infections.

Use of Saliva in Diagnosis of Periodontitis: Cumulative Use of Bacterial and Host-Derived Biomarkers

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451241 Year: Pages: 105 DOI: 10.3389/978-2-88945-124-1 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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Periodontitis is an infection-induced inflammatory disease of the tooth supporting tissues. Treatment of periodontal diseases and regeneration of the effected tissues can be possible only in the early diagnosis of the disease. If left undiagnosed or untreated, periodontitis leads to irreversible soft and hard tissue destruction and finally to tooth loss. Saliva is known to contain inflammatory mediators, host tissue and cell degradation products as well as microbial metabolites and enzymes, reflecting the health status of the oral cavity. In this topic, in collaboration with the well-known scientists working on the field of salivary diagnostics, we demonstrate evidence on monitoring periodontitis by salivary analysis.

Microbial and Environmental Factors in Autoimmune and Inflammatory Diseases

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451555 Year: Pages: 193 DOI: 10.3389/978-2-88945-155-5 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General) --- Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2017-08-28 14:01:09
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In recent years there has been a substantial increase in the number of diseases with the inflammatory component such as such as allergy, asthma, rheumatoid arthritis, inflammatory bowl disease (IBD, which includes ulcerative colitis and Crohn's disease), chronic sinusitis, and many other conditions. The majority of these diseases are multifactorial, with the contribution of genetic and environmental factors. Among the latter, the role of certain microorganisms and viruses in triggering or sustaining the inflammatory process is most controversial. In rheumatoid arthritis, for example, the following bacteria and viruses have been implicated in triggering the disease: Mycoplasma spp., Proteus mirabilis, Escherichia coli, Staphylococcus spp., Bordetella spp., Acinetobacter spp., the parvoviruses, Epstein-Barr virus, and retroviruses. The list of putative microbial triggers of rheumatoid arthritis is still growing, and it becomes essentially impossible to make a causation link between certain infectious agents and the disease. In the light of these disappointing results there are calls for even larger studies with the use of more advanced and large-scale technologies. The primary function of the immune system is the maintenance of body homeostasis and protection against any threats to it via several lines of elaborate and complex immune defense. Given even higher complexity that involves the microbiota and the corresponding host-microbe interaction, the conditions for this equilibrium become even more challenging. In the absence of a defined pathogen, for example, the spectrum of microorganisms involved in triggering inappropriate immune responses may include polymicrobial communities or the cumulative effect of several microbial/viral factors. Under the normal circumstances there is a fine-tuned balance between commensal microbiota and the host’s immune responses. However, when this balance is compromised, for example in IBD, a massive immune response is launched against commensal microbiota resulting in chronic inflammation. Besides the microbial/viral factors, the balance of the immune system can be compromised by other causes. Given, for example, the close and inclusive interaction of the immune, nervous and endocrine systems, the list of these provoking factors can expand even more. For instance, it has been demonstrated that even mild sleep deprivation may increase the production of interleukin-6 and C-reactive protein. Understanding the complex role of microbial and environmental factors in inflammatory and autoimmune diseases, therefore, is the main subject of this topic.

Microbial Food Safety Along The Dairy Chain

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453122 Year: Pages: 148 DOI: 10.3389/978-2-88945-312-2 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology --- Medicine (General) --- Nutrition and Food Sciences
Added to DOAB on : 2018-02-27 16:16:45
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The dairy chain is an integral part of global food supply, with dairy food products a staple component of recommended healthy diets. The dairy food chain from production through to the consumer is complex, with various opportunities for microbial contamination of ingredients or food product, and as such interventions are key to preventing or controlling such contamination. Dairy foods often include a microbial control step in their production such as pasteurization, but in some cases may not, as with raw milk cheeses. Microbial contamination may lead to a deterioration in food quality due to spoilage organisms, or may become a health risk to consumers should the contaminant be a pathogenic microorganism. As such food safety and food production are intrinsically linked. This Research Topic eBook includes submissions on issues relating to the microbiological integrity of the dairy food chain, such as the ecology of pathogenic and spoilage organisms through the dairy farm to fork paradigm, their significance to dairy foods and health, and genomic analysis of these microorganisms.

Plant Microbe Interaction 2017

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ISBN: 9783038973287 9783038973294 Year: Pages: 262 DOI: 10.3390/books978-3-03897-329-4 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology --- Plant Sciences
Added to DOAB on : 2018-11-14 11:21:52
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ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms.[Plants interact with microbes in many different ways and on many different levels. The most obvious interaction results in plant disease, which can be a severe threat to the global food supply. Therefore, research strives to uncover the mechanisms of host plant invasion, learn about the weapons used by pathogenic microbes, and understand the defense strategies of the affected plants. On the other hand, many interactions with the plant are indeed beneficial for the plant, increasing its ability to recruit limiting nutrients from the soil, preventing the growth of more detrimental microbes, or making the plant more resistant to abiotic stresses. Plants also serve as habitats for microbes that may colonize apoplastic spaces within leaves, may live on plant surfaces, or may prosper in the immediate vicinity of plant organs (e.g., in the rhizosoil). In this book, one editorial, two review articles, and twelve original research articles highlight the newest research endeavors on plants interacting with beneficial microbes, having to cope with detrimental microbes, or hosting complete microbiomes. Together, these articles contribute to the knowledge essential for the development of strategies that will prepare our plants to withstand the increasingly harsh conditions they will be exposed to in the coming years of climate change.]

Coupled 3D hydrodynamic models for submarine outfalls. Denvironmental hydraulic design and control of multiport diffusers

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Book Series: Dissertationsreihe am Institut für Hydromechanik der Universität Karlsruhe ISSN: 14394111 ISBN: 9783866441606 Year: Volume: 2006,3 Pages: 219 p. DOI: 10.5445/KSP/1000006668 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: General and Civil Engineering
Added to DOAB on : 2019-07-30 20:01:59
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The book describes the hydraulic design and environmental impact prediction technologies for such installations. Focus are the hydrodynamics approached by computer models. First, a multiport diffuser design program was developed. Second, two model systems for discharge analysis, CORMIX for the near-field and intermediate-field and Delft3D for the far-field were coupled, and third a regulatory procedure is proposed to license and monitor outfall installations.

Gram-positive phages: From isolation to application

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194933 Year: Pages: 120 DOI: 10.3389/978-2-88919-493-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology
Added to DOAB on : 2015-11-16 15:44:59
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Phage biology is one of the most significant and fundamental aspects of biological research and is often used as a platform for model studies relating to more complex biological entities. For this reason, phage biology has enjoyed focused attention and significant advances have been made in the areas of phage genomics, transcriptomics and the development and characterisation of phage-resistance mechanisms. In recent years, considerable research has been performed to increase our understanding of the interactions of these phages with their hosts using genomic, biochemical and structural approaches. Such multidisciplinary approaches are core to developing a full understanding of the processes that govern phage infection, information that may be harnessed to develop anti-phage strategies that may be applied in food fermentations or applied in a positive sense in phage therapy applications. The co-evolutionary processes of these phages and their hosts have also been a considerable focus of research in recent years. Such data has promoted a deeper understanding of the means by which these phages attach to and infect their hosts and permitted the development of effective anti-phage strategies. Furthermore, the presence and activity of host-encoded phage-resistance systems that operate at various stages of the phage cycle and the potential for the application of such systems consolidates the value of research in this area. Conversely, phages and their components have been applied as therapeutic agents against a number of pathogens including, among others, Clostridium difficile, Lactococcus garviae, Mycobacterium spp., Listeria spp. and the possibilities and limitations of these systems will be explored in this topic. Additionally, phage therapeutic approaches have been applied to the prevention of development of food spoilage organisms in the brewing and beverage sectors and exhonorate the positive applications of phages in the industrial setting. This research topic is aimed to address the most current issues as well as the most recent advances in the research of phages infecting Gram-positive bacteria covering areas such as phages in food fermentations, their impact in industry, phage ecology, genomics, evolution, structural analysis, phage-host interactions and the application of phages and components thereof as therapeutic agents against human and animal pathogens.

Intracellular biomineralization in bacteria

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192724 Year: Pages: 135 DOI: 10.3389/978-2-88919-272-4 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Oceanography --- Science (General)
Added to DOAB on : 2015-12-03 13:02:24
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Bacteria can sequester metals and other ions intracellularly in various forms ranging from poorly ordered deposits to well- ordered mineral crystals. Magnetotactic bacteria provide one example of such intracellular deposits. They synthesize intracellular magnetic minerals of magnetite (Fe3O4) and/or greigite (Fe3S4) magnetosomes which are generally less than 150 nm and organized into one or multiple chain structures. The magnetosome chain(s) act like a compass needle to facilitate the navigation of magnetotactic bacteria by using the Earth's magnetic field. Due to their ubiquitous distribution in aquatic and sedimentary environments, magnetotactic bacteria play important roles in global iron cycling. Other intracellular mineral phases have been evidenced in bacteria such as As2S3, CaCO3, CdS, Se(0) or various metal phosphates which may play as well a significant role in the geochemical cycle of these elements. However, in contrast to magnetotactic bacteria, the biological and environmental function of these particles remains a matter of debate. In recent years, such intracellularly biomineralizaing bacteria have become an attractive model system for investigating the molecular mechanisms of organelle-like structure formation in prokaryotic cells. The geological significance of intracellular biomineralization is important; spectacular examples are fossil magnetosomes that may significantly contribute to the bulk magnetization of sediments and act as potential archives of paleoenvironmental changes. In addition, intracellular mineral deposits formed by bacteria have potentially versatile applications in biotechnological and biomedical fields. After more than four decades of research, the knowledge on intracellularly biomineralizing bacteria has greatly improved. The aim of this Research Topic is to highlight recent advances in our understanding of intracellular biomineralization by bacteria. Magnetotactic bacteria are a system of choice for that topic but other intracellularly biomineralizing bacteria may bring a unique perspective on that process. Research papers, reviews, perspectives, and opinion papers on (i) the diversity and ecology of intracellularly biomineralizing bacteria, (ii) the molecular mechanisms of intracellular biomineralization, (iii) the chemo- and magneto-taxis behaviors of magnetotactic bacteria, (iv) the involvement of intracellularly biomineralizing bacteria in local or global biogeochemical cycling, (v) the paleoenvironmental reconstructions and paleomagnetic signals based on fossil magnetosomes, (vi) and the applications of intracellular minerals in biomaterial and biotechnology were welcomed.

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