نتایج جستجو برای: sinorhizobium
تعداد نتایج: 1682 فیلتر نتایج به سال:
Resting cell assay and soil microcosms were set up to investigate the biodegradation capability and metabolic intermediate of polychlorinated biphenyls (PCBs) by a rhizobial strain Sinorhizobium meliloti. Biodegradation was observed immediately after 2,4,4'-TCB was supplied as a sole source of carbon and energy in liquid cultures. After 6 days, the percent biodegradation of 2,4,4'-TCB was 77.4%...
The nodulation genes of Mesorhizobium sp. (Astragalus sinicus) strain 7653R were cloned by functional complementation of Sinorhizobium meliloti nod mutants. The common nod genes, nodD, nodA, and nodBC, were identified by heterologous hybridization and sequence analysis. The nodA gene was found to be separated from nodBC by approximately 22 kb and was divergently transcribed. The 2. 0-kb nodDBC ...
Seventeen arginine auxotrophic mutants of Sinorhizobium meliloti Rmd201 were isolated by random transposon Tn5 mutagenesis using Tn5 delivery vector pGS9. Based on intermediate feeding studies, these mutants were designated as argA/argB/argC/argD/argE (ornithine auxotrophs), argF/argI, argG and argH mutants. The ornithine auxotrophs induced ineffective nodules whereas all other arginine auxotro...
The scarcity of usable nitrogen frequently limits plant growth. A tight metabolic association with rhizobial bacteria allows legumes to obtain nitrogen compounds by bacterial reduction of dinitrogen (N2) to ammonium (NH4+). We present here the annotated DNA sequence of the alpha-proteobacterium Sinorhizobium meliloti, the symbiont of alfalfa. The tripartite 6.7-megabase (Mb) genome comprises a ...
Whole-genome transcriptional profiling was used to identify genes in Sinorhizobium meliloti 1021 that are differentially expressed during exposure to elevated concentrations of cadmium and zinc. Mutant strains with insertions in metal-regulated genes and in genes encoding putative metal efflux pumps were analyzed for their metal sensitivities, revealing a crucial role for the SMc04128-encoded P...
The origins of replication of many different bacteria have been shown to reside at specific subcellular locations, but the mechanisms underlying their positioning and segregation are still being elucidated. In particular, little is known about the replication of multipartite genomes in bacteria. We determined the cellular positions of the origins of the replicons in the alpha proteobacteria Agr...
Twenty three pyrimidine auxotrophs of Sinorhizobium meliloti Rmd201 were generated by random mutagenesis with transposon Tn5. On the basis of biochemical characters these auxotrophic mutants were classified into car, pyrC and pyrE/pyrF categories. All auxotrophs induced white nodules which were ineffective in nitrogen fixation. Light and electron microscopic studies revealed that the nodules in...
Rhizobial nodulation (Nod) factors activate both nodule morphogenesis and infection thread development during legume nodulation. Nod factors induce two different calcium responses: intra-nuclear calcium oscillations and a calcium influx at the root hair tip. Calcium oscillations activate nodule development; we wanted to test if the calcium influx is associated with infection. Sinorhizobium meli...
UNLABELLED The mechanisms and organisms involved in the natural formation of volatile organohalogen compounds (VOX) are largely unknown. We provide evidence that the common and widespread soil bacterium Sinorhizobium meliloti strain 1021 is capable of producing up to 3338·6 ± 327·8 ng l(-1) headspace volume of chloroform (CHCl3 ) and 807·8 ± 13·5 ng l(-1) headspace volume of tetrachloroethene ...
Soil bacteria, such as Sinorhizobium meliloti, are subject to variation in environmental conditions, including carbon- and nitrogen-deprivation. The ability of bacteria to sense changes in their environment and respond accordingly is of vital importance to their survival and persistence in the soil and rhizosphere. A derivative of Tn5 which creates transcriptional fusions to the promoterless lu...
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