Search results for "Bacteria"

Transformation of Construction Cement to a Self-Healing Hybrid Binder

2019

A new biomimetic strategy to im prove the self-healing properties of Portland cement is presented that is based on the application of the biogenic inorganic polymer polyphosphate (polyP), which is used as a cement admixture. The data show that synthetic linear polyp, with an average chain length of 40, as well as natural long-chain polyP isolated from soil bacteria, has the ability to support self-healing of this construction material. Furthermore, polyP, used as a water-soluble Na-salt, is subject to Na+/Ca2+ exchange by the Ca2+ from the cement, resulting in the formation of a water-rich coacervate when added to the cement surface, especially to the surface of bacteria-containing cement/c…

Happens in the best of subfamilies: establishment and repeated replacements of co-obligate secondary endosymbionts within Lachninae aphids.

2016

SummaryVirtually all aphids maintain an obligate mutualistic symbiosis with bacteria from theBuchneragenus, which produce essential nutrients for their aphid hosts. Most aphids from the Lachninae subfamily have been consistently found to house additional endosymbionts, mainlySerratia symbiotica. This apparent dependence on secondary endosymbionts was proposed to have been triggered by the loss of the riboflavin biosynthetic capability byBuchnerain the Lachninae last common ancestor. However, an integral large-scale analysis of secondary endosymbionts in the Lachninae is still missing, hampering the interpretation of the evolutionary and genomic analyses of these endosymbionts. Here, we anal…

Biodeterioration

2017

The biodeterioration of organic and inorganic materials, as well as polymers, is a complex of alteration processes induced by the growing and metabolic activ- ity of organisms. It can be recognized on monuments, wall paintings, stone, wood, paper, vegetal/animal fibers, and parchment artworks. As defined by Hueck (1968), biodeterioration is “any undesirable change in the properties of a material caused by the vital activities of organisms”; this definition is accepted as the meaning of the phenomenon. Both macroorganisms (such as animals, plants and mosses) and microorganisms (such as autotrophic or het- erotrophic bacteria, microfungi, cyanobacteria, algae and lichens) represent the trigge…

Zelloberflächenstrukturen der Bacteria und Archaea

2016

Evaluation of Antibacterial Efficacy of Photodynamic Therapy vs. 2.5% NaOCl against E. faecalis-infected Root Canals Using Real-time PCR Technique

2017

Background Bacteria like E. faecalis can produce intra- and extra-radicular biofilms. Theoretically, the adjustable penetration ability of lasers enables better access to root canal system. Therefore the aim of the present study was to compare the ability of photoactivated laser and 2.5% NaOCl irrigation solution to eliminate E. faecalis from the root canals by real-time PCR technique. Material and methods Sixty extracted human upper central incisors were selected and sterilized in an autoclave. The root canals were infected with E. faecalis (PTCC 1237, Persian Type Culture Collection, Iran) and then incubated for 24 hours. The samples were randomly divided into 3 groups. No intervention wa…

Roles for RpoS in survival of Escherichia coli during protozoan predation and in reduced moisture conditions highlight its importance in soil environ…

2017

The soil is a complex ecosystem where interactions between biotic and abiotic factors determine the survival and fate of microbial inhabitants of the system. Having previously shown that Escherichia coli requires the general stress response regulator, RpoS, to survive long term in soil, it was important to determine what specific conditions in this environment necessitate a functional RpoS. This study investigated the susceptibility of soil-persistent E. coli to predation by the single-celled eukaryotes Acanthamoeba polyphaga and Tetrahymena pyriformis, and the role RpoS plays in resisting this predation. Strain-specific differences were observed in the predation of E. coli strains, with so…

Dysbiosis in marine aquaculture revealed through microbiome analysis: reverse ecology for environmental sustainability

2020

AbstractThe increasing demand for products for human consumption is leading to the fast-growing expansion of numerous food sectors such as marine aquaculture (mariculture). However, excessive input of nutrients and pollutants modifies marine ecosystems. Here, we applied a metagenomic approach to investigate these perturbations in samples from marine farms of gilthead seabream cultures. Results revealed dysbiosis and functional imbalance within the net cage with a unique structure, with little interference with samples from the fish microbiota or those collected far away from the coast. Remarkably, below the cage the prokaryotic community was highly similar to the marine microbiome of photic…

Anti-Listeria activity of lactic acid bacteria in two traditional Sicilian cheeses

2017

<em>Listeria monocytogenes</em> is a pathogen frequently found in dairy products, and its growth is difficult to control. Bacteriocinlike inhibitory substances (BLIS), produced by lactic acid bacteria (LAB), having proven <em>in vitro</em> anti-<em>Listeria</em> activity, could provide an innovative approach to control <em>L. monocytogenes</em>; however, this application needs to be evaluated <em>in vivo</em>. In this study, twenty LAB strains isolated from different Sicilian dairy environments were tested for control of growth of <em>L. monocytogenes</em> in three different experimental trials. First, raw and UHT milk …

Cellular Concentrations of the Transporters DctA and DcuB and the Sensor DcuS of Escherichia coli and the Contributions of Free and Complexed DcuS to…

2017

ABSTRACT In Escherichia coli , the catabolism of C 4 -dicarboxylates is regulated by the DcuS-DcuR two-component system. The functional state of the sensor kinase DcuS is controlled by C 4 -dicarboxylates (like fumarate) and complexation with the C 4 -dicarboxylate transporters DctA and DcuB, respectively. Free DcuS (DcuS F ) is known to be constantly active even in the absence of fumarate, whereas the DcuB-DcuS and DctA-DcuS complexes require fumarate for activation. To elucidate the impact of the transporters on the functional state of DcuS and the concentrations of DcuS F and DcuB-DcuS (or DctA-DcuS), the absolute levels of DcuS, DcuB, and DctA were determined in aerobically or anaerobic…

Bioprospecting challenges in unusual environments

2017

Editorial: The microbiome as a source of new enterprises and job creation.