Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger Quorum Sensing (QS) response, which activates expression genes involved in a series alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production public goods, or pathogenicity factors, among others). Contrary most autoinduce...

Microaerophilic Fe(II)-oxidizing bacteria are often chemolithoautotrophs, and the Fe(III) (oxyhydr)oxides they form could immobilize arsenic (As). If such microbes active in karstic paddy soils, their activity would help increase soil organic carbon mitigate As contamination. We therefore used gel-stabilized gradient systems to cultivate microaerophilic from investigate capacity for Fe(II) oxid...

We explored N2 fixation and alkaline phosphatase activity (APA) in periphyton from a N-limited stream ecosystem by coupling measurements of these processes with nutrient diffusion substrata (NDS) experiments. We measured periphyton biomass accumulation (as ash-free dry mass [AFDM] and chlorophyll a [CHLA]), N2 fixation, and APA to evaluate the relative importance of N2 fixation as an N source t...

In Brazil, the common bean is a crop with significant social and economic importance. The prospecting of N2 fixing bacteria crucial since biological nitrogen fixation (BNF) an eco-friendly technique. This work aimed to obtain characterize rhizobium isolates based on morpho-physiological, molecular, symbiotic efficiency parameters, using strains SEMIA 4077, 4080, 4088 as references. characterist...

Although most organisms, including all eucaryotes, cannot assimilate atmospheric dinitrogen (N2), a group of evolutionarily divergent procaryotes are able to reduce N2 directly to ammonia (nitrogen fixation) under a variety of physiological conditions. The molecular genetics of nitrogen fixation has been studied primarily in Klebsiella pneumoniae because of its close taxonomic relation to Esche...

We measured N2 fixation rates from oceanic zones that have traditionally been ignored as sources of biological N2 fixation; the aphotic, fully oxygenated, nitrate (NO(-) 3)-rich, waters of the oligotrophic Levantine Basin (LB) and the Gulf of Aqaba (GA). N2 fixation rates measured from pelagic aphotic waters to depths up to 720 m, during the mixed and stratified periods, ranged from 0.01 nmol N...

Anthropogenic nitrogen (N) input is known to alter the soil microbiome, but how N enrichment influences abundance, alpha-diversity and community structure of N-cycling functional microbial communities in grasslands remains poorly understood. Here, we collected soils from plant subjected up 9 years annual N-addition (10 g m−2 per year using urea as a N-source) unfertilized plots (control) 30 wor...

The metallic corrosion is a spontaneous process that causes damage in almost all sectors of human activity. Among the most affected structures stand out the pipes for oil transportation. The biocorrosion occurs due to the fixation of bacteria, release of metabolites and formation of biofilms that induce or accelerate the corrosion process. Among the groups of bacteria involved in the corrosion ...