Search results for "bacteri"
showing 10 items of 5466 documents
Dynamic of the genetic structure of bacterial and fungal communities at different developmental stages of Medicago truncatula Gaertn. cv. Jemalong li…
2006
International audience; The genetic structure of bacterial and fungal communities was characterized in the rhizosphere of Medicago truncatula Gaertn. cv. Jemalong line J5 at five developmental stages (three vegetative and two reproductive stages), and in three compartments (bulk soil, rhizosphere soil and root tissues). The genetic structure of microbial communities was determined by cultivation-independent methods using directly extracted DNA that was characterized by automated ribosomal intergenic spacer analysis (ARISA). Principal component analyses (PCA) indicate that, for all developmental stages, the genetic structure of microbial communities differed significantly by compartment, wit…
Similarities and singularities of three DnaK proteins from the cyanobacterium Synechocystis sp. PCC 6803.
2010
In the genome of completely sequenced mesophilic cyanobacterium Synechocystis sp. PCC 6803 three DnaK proteins are encoded, which share a high degree of sequence identity in their N-terminal ATPase region as well as in the adjacent peptide-binding domain. However, as typical for DnaK proteins, the C-termini of the three Synechocystis proteins are highly diverse. To study the functions of the three Synechocystis DnaK proteins in more detail, we have analyzed the abundance of the individual proteins in Synechocystis cells as well as dnaK expression under various stress conditions. The presented results show that all three Synechocystis DnaK proteins interact with the same GrpE nucleotide exch…
Chemical Composition Analysis, Antimicrobial Activity and Cytotoxicity Screening of Moss Extracts (Moss Phytochemistry)
2015
Mosses have been neglected as a study subject for a long time. Recent research shows that mosses contain remarkable and unique substances with high biological activity. The aim of this study, accordingly, was to analyze the composition of mosses and to screen their antimicrobial and anticancer activity. The total concentration of polyphenols and carbohydrates, the amount of dry residue and the radical scavenging activity were determined for a preliminary evaluation of the chemical composition of moss extracts. In order to analyze and identify the substances present in mosses, two types of extrahents (chloroform, ethanol) and the GC/MS and LC-TOF-MS methods were used. The antimicrobial activ…
A model for the effect of pH on the growth of chalk yeasts.
2013
Hyphopichia burtonii, Pichia anomala, and Saccharomycopsis fibuligera were isolated from spoiled packaged sliced bread. These chalk yeasts were characterized by a wide range of pH for which growth was almost optimum. Thus, the curve growth vs pH exhibited plateau and sharp profiles close to the minimum and the maximum pH. This study described a chalk yeast model (CYM) for the effect of pH derived from a new germination model for fungi (Dantigny, P., Nanguy, S., P.-M., Judet-Correia, D., and Bensoussan, M. 2011, International Journal of Food Microbiology, 146, 176-181). The CYM is asymmetric, versatile, based on parameters with biological significance, and compatible with the gamma concept. …
Bifunctional dentifrice: Amorphous polyphosphate a regeneratively active sealant with potent anti- Streptococcus mutans activity
2017
Abstract Objective In this study we demonstrate that inorganic polyphosphate (polyP) exhibits a dual protective effect on teeth: it elicits a strong antibacterial effect against the cariogenic bacterium Streptococcus mutans and, in form of amorphous calcium polyP microparticles (size of 100–400 nm), it efficiently reseals cracks/fissures in the tooth enamel and dentin. Methods Three different formulations of amorphous polyP microparticles (Ca-polyP, Zn-polyP and Sr-polyP) were prepared. Results Among the different polyP microparticles tested, the Ca-polyP microparticles, as a component of a newly developed formulation of a dentifrice, turned out to be most effective in inhibiting growth of …
Hygienic characteristics of radishes grown in soil contaminated with Stenotrophomonas maltophilia
2015
Background: Stenotrophomonas maltophilia is a plant growth-promoter. This bacterium is also implicated in human diseases. Thus, after the use of this bacterium in agriculture, the safety of the final products has to be verified. Due to the ubiquitous presence of S. maltophilia in soil, in this study a massive contamination was simulated to evaluate the growth and safety of Raphanus sativus L.. Results: Different inoculums and soil treatment conditions were tested. Soils were analysed weekly and the radishes at harvest for their microbial loads and presence/persistence of S. maltophilia LMG 6606. The concentration of the bacterium added in the different trials decreased during the first week…
The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea
2019
Selenium (Se) is an essential micronutrient but toxic when taken in excessive amounts. Therefore, understanding the metabolic processes related to selenium uptake and bacteria-plant interactions coupled with selenium metabolism are of high importance. We cultivated Brassica oleracea with the previously isolated heterotrophic aerobic Se(IV)-reducing Pseudomonas sp. T5-6-I strain to better understand the phenomena of bacteria-mediated Se(IV) reduction on selenium availability to the plants. B. oleracea grown on Murashige and Skoog medium (MS-salt agar) with and without of Pseudomonas sp. were amended with Se(IV)/75Se(IV), and selenium transfer into plants was studied using autoradiography and…
Molecular and agronomic responses to plant-growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi in durum wheat
2013
Plant-growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi contribute to plant nutrient uptake by increasing the availability of nutrients and the root adsorbing surface (Garg et al., 2006; Asghar et al. 2002). The first objective of this study was to determine the effects of these associations on plant total biomass and grain yield in durum wheat (cv. Anco Marzio). Secondly, we aimed to analyze the root transcriptomic and metabolomic changes in response to mychorrizal infections and the expression pattern of key genes involved in nutrient uptake and stress responses. Field analysis were carried out in inner Sicily, a typical Mediterranean area. Four types of biotic a…
Isolation and purification of plasmids from Bacteroides fragilis using rubidium trichloroacetate density gradient centrifugation.
1983
A rapid and easy final purification method is described for the isolation of plasmids from B. fragilis. Using RbTCA density gradient centrifugation in an airfuge ultracentrifuge ccc plasmid DNA can be separated from RNA, residual chromosomal DNA, linear and oc plasmid DNA. Pure ccc plasmid DNA is obtained from cultures of between 1 ml and 2 l in less than one day.
Multi-plasmid clash in a bacterial community: plasmid viability depends on the ecological setting of hosts
2021
AbstractPlasmids are genetic elements that disperse horizontally between different strains and species of bacteria and a major factor in the dissemination of virulence factors and antibiotic resistance. Understanding the ecology of plasmids has a notable anthropocentric value and therefore the interactions between bacterial hosts and individual plasmids have been studied in detail. However, bacterial systems often carry multiple genetically distinct plasmids, but dynamics of these multiplasmid “clashes” has remained unstudied. Here, we set to investigate the survival of 11 mobilizable or conjugative plasmids in five different ecological settings. The key incentive was to determine whether p…