Search results for "bacteri"
showing 10 items of 5466 documents
Influence of land-use intensity on the spatial distribution of N-cycling microorganisms in grassland soils
2011
A geostatistical approach using replicated grassland sites (10 m × 10 m) was applied to investigate the influence of grassland management, i.e. unfertilized pastures and fertilized mown meadows representing low and high land-use intensity (LUI), on soil biogeochemical properties and spatial distributions of ammonia-oxidizing and denitrifying microorganisms in soil. Spatial autocorrelations of the different N-cycling communities ranged between 1.4 and 7.6 m for ammonia oxidizers and from 0.3 m for nosZ-type denitrifiers to scales >14 m for nirK-type denitrifiers. The spatial heterogeneity of ammonia oxidizers and nirS-type denitrifiers increased in high LUI, but decreased for biogeochemical …
The effect of a temperature-sensitive prophage on the evolution of virulence in an opportunistic bacterial pathogen
2019
AbstractViruses are key actors of ecosystems and have major impacts on global biogeochemical cycles. Prophages deserve particular attention as they are ubiquitous in bacterial genomes and can enter a lytic cycle when triggered by environmental conditions. We explored how temperature affects the interactions between prophages and other biological levels by using an opportunistic pathogen, the bacterium Serratia marcescens, that harbours several prophages and that had undergone an evolution experiment under several temperature regimes. We found that the release of one of the prophages was temperature-sensitive and malleable to evolutionary changes. We further discovered that the virulence of …
Prevalence of genetically similarFlavobacterium columnarephages across aquaculture environments reveals a strong potential for pathogen control
2020
SummaryIntensive aquaculture conditions expose fish to bacterial infections, leading to significant financial losses, extensive antibiotic use and risk of antibiotic resistance in target bacteria.Flavobacterium columnarecauses columnaris disease in aquaculture worldwide. To develop a bacteriophage-based control of columnaris disease, we isolated and characterized 126F. columnarestrains and 63 phages againstF. columnarefrom Finland and Sweden. Bacterial isolates were virulent on rainbow trout (Oncorhynchus mykiss) and fell into four previously described genetic groups A, C, E and G, with genetic groups C and E being the most virulent. Phage host range studied against a collection of 228 bact…
Versatile and Dynamic Symbioses Between Insects and Burkholderia Bacteria
2020
Symbiotic associations with microorganisms represent major sources of ecological and evolutionary innovations in insects. Multiple insect taxa engage in symbioses with bacteria of the genus Burkholderia, a diverse group that is widespread across different environments and whose members can be mutualistic or pathogenic to plants, fungi, and animals. Burkholderia symbionts provide nutritional benefits and resistance against insecticides to stinkbugs, defend Lagria beetle eggs against pathogenic fungi, and may be involved in nitrogen metabolism in ants. In contrast to many other insect symbioses, the known associations with Burkholderia are characterized by environmental symbiont acquisition …
Use Of Plants To Remediate Soil Polluted With Oil
2015
In the present investigation the growing and development ability of various annual and perennial plants to grow on model peat substrate artificially polluted with oil products in the range of concentrations from 1 to 5% was evaluated. The highest tolerance towards peat contamination by oil products has been demonstrated by three annual crops (maize, oat and lupine). These plants were tested for phytoremediation of polluted black soil from the area of oil refinery plant (Mazeikiai, Lithuania), which was treated by association of oil oxidizing bacteria up to residual concentration of the oil products of 4.5 %. The maize plants revealed the highest remediation ability: oil content in the soil …
Métabolisme sucre-citrate chez Leuconostoc mesenteroides
2001
Sugar citrate cometabolism in Leuconostoc mesenteroides. Bacteria from the genus Leuconostocplay roles in the dairy industry. The most important functions of this bacteria are their ability to produce CO 2 and flavour compounds through lactose heterofermentation and citrate uti- lization. Although the biotechnological role of the citrate metabolism is very important and widely appreciated, little is known about the genetic properties of Leuconostoc spp. In our laboratory, we cloned the genes responsible for citrate metabolism ( clyR mae citCDEFGOPcluster), for D-lactate dehydrogenase (ldhD) and for phosphotransacetylase ( pta). In addition we have planned to con- struct new vectors and we h…
Partial purification and characterization of an NAD-dependent 3 beta-hydroxysteroid dehydrogenase from Clostridium innocuum
1989
In nine strains of Clostridium innocuum, 3 beta-hydroxysteroid-dehydrogenating activities were detected. 3 beta, 7 alpha, 12 alpha-Trihydroxy- and 3 beta-hydroxy-12-keto-5 beta-cholanoic acids were identified as reduction products of the respective 3-keto bile acids by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry. One strain was shown to contain a NAD-dependent 3 beta-hydroxysteroid dehydrogenase. Enzyme production was constitutive in the absence of added bile acids. The specific enzyme activity was significantly reduced by growth medium supplementation with 3-keto bile acids, with trisubstituted acids being more effective than disubstituted ones. A pH optimum o…
Synthesis of New 2-{[(Phenoxy or Phenyl)acetyl]amino}benzoic Acid Derivatives as 3α-Hydroxysteroid Dehydrogenase Inhibitors and Potential Antiinflamm…
1995
A number of 2-([(phenoxy or phenyl)acetyl]amino)benzoic acid derivatives were prepared in about 50% yield from (phenoxy or phenyl)acetyl chloride and anthranilic acid derivatives. All the compounds were tested as in vitro inhibitors of 3 alpha-hydroxysteroid dehydrogenase, since enzyme inhibition predicts potential antiinflammatory activity in vivo. The most active compounds 3 l, m, s are about 3.5 times more active than acetylsalicylic acid (ASA). Activity is influenced by electronic as well as steric effects.
Evaluation of the antibacterial power and biocompatibility of zinc oxide nanorods decorated graphene nanoplatelets: New perspectives for antibiodeter…
2017
Background Nanotechnologies are currently revolutionizing the world around us, improving the quality of our lives thanks to a multitude of applications in several areas including the environmental preservation, with the biodeterioration phenomenon representing one of the major concerns. Results In this study, an innovative nanomaterial consisting of graphene nanoplatelets decorated by zinc oxide nanorods (ZNGs) was tested for the ability to inhibit two different pathogens belonging to bacterial genera frequently associated with nosocomial infections as well as biodeterioration phenomenon: the Gram-positive Staphylococcus aureus and the Gram-negative Pseudomonas aeruginosa. A time- and dose-…
Nanodesign of new self-assembling core-shell gellan-transfersomes loading baicalin and in vivo evaluation of repair response in skin
2017
Gellan nanohydrogel and phospholipid vesicles were combined to incorporate baicalin in new self-assembling core-shell gellan-transfersomes obtained by an easy, scalable method. The vesicles were small in size (~107 nm) and monodispersed (P.I. ≤ 0.24), forming a viscous system (~24 mPa/s) as compared to transfersomes (~1.6 mPa/s), as confirmed by rheological studies. Gellan was anchored to the bilayer domains through cholesterol, and the polymer chains were distributed onto the outer surface of the bilayer, thus forming a core-shell structure, as suggested by SAXS analyses. The optimal carrier ability of core-shell gellan-transfersomes was established by the high deposition of baicalin in th…