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Nowadays, genetically modified plants are cultivated in many countries and it is important to consider their safety for surrounding environment. So, the environmental risk assessments of genetically modified plants are evaluated. This assessment consists of an objective evaluation of risk and involves generating; collecting and assessing of information on a GM plant with the aim to determine its impact on human or animal health and the environment relative to non-genetically modified organisms. One of the numerous methods used to investigate the impact of GM plants on the environment is the Terminal Restriction Fragment Length Polymorphism. This method was used for comparison of genetic variation in populations of bacteria isolated from rhizosphere of genetically modified maize MON810 carrying the gene cry1Ab and genetically non-modified maize. Rhizosphere samples were collected in Slovakia during two years (2008, 2009) in July and September and 16S rRNA gene was amplified from metagenomic DNA using universal eubacterial primers. Differences in the number of terminal restriction fragments between control and GM maize hybrids were not detected. Additionally, variation within bacterial communities composition from rhizosphere of MON810 and non-GM hybrids was not observed, nevertheless negligible differences in composition of bacterial community were observed between two sampling periods (July and September). These changes were observed in non-GM as well as in GM maize hybrids and reflected effects of environment and conditions, no influence of genetic modification. The 16S rDNA clone library creation from rhizosphere sample of MON810 maize followed by DNA sequencing revealed that the Proteobacteria were major group of bacteria and Actinobacteria, Firmicutes, and Chloroflexi were less represented. This study did not confirm any changes in the soil ecosystem, which would have been larger than normal variations caused by external conditions.
Molecular diversity studies of 19 rhizobia isolates from chickpea were conducted using simple sequence repeats (SSR) and 16S rDNA-RFLP markers. Phenotypic characterization with special reference to salinity and pH tolerance was performed. These isolates were identified as different strains of Mesorhizobium, Rhizobium, Bradyrhizobium, and Agrobacterium. Twenty SSR loci of Mesorhizobium ciceri, distributed across the other rhizobial genome, clearly differentiated 19 rhizobial isolates. Analogous clustering supported the results of 16S rDNA sequence-based phylogeny. Analysis of the 16S rDNA sequences from M. ciceri strains revealed that nucleotide variables (signature sites) were located at 20 different positions; most of them were present in the first 820 bp region from 5’ terminal. Interestingly, 14 signature sites were located in two main regions, the variable region V1 (nt 527–584), and variable region V2 (nt 754–813). The secondary structure and minimal free energy were determined in these two regions. These results will be useful in characterizing the micro-evolutionary mechanisms of species formation and increase understanding of the symbiotic relationship.
Males, females, and larvae of Carios fonsecai sp. nov. are described from free-living ticks collected in a cave at Bonito, state of Mato Grosso do Sul, Brazil. The presence of cheeks and legs with micromammillate cuticle makes adults of C. fonsecai morphologically related to a group of argasid species (mostly bat-associated) formerly classified into the subgenus Alectorobius, genus Ornithodoros. Examination of larvae indicates that C. fonsecai is clearly distinct from most of the previously described Carios species formerly classified into the subgenus Alectorobius, based primarily on its larger body size, dorsal setae number, dorsal plate shape, and hypostomal morphology. On the other hand, the larva of C. fonsecai is most similar to Carios peropteryx, and Carios peruvianus, from which differences in dorsal plate length and width, tarsal setae, and hypostome characteristics are useful for morphological differentiation. The mitochondrial 16S rDNA sequence of C. fonsecai showed to be closest (85–88% identity) to several corresponding sequences of different Carios species available in GenBank. Bats identified as Peropteryx macrotis and Desmodus rotundus were found infested by C. fonsecai larvae in the same cave where the type series was collected. C. fonsecai showed to be aggressive to humans in the laboratory.
The haloarchaeal diversity of a salt mine, a natural cave in central Anatolia, was investigated using convential microbiological and molecular biology methods. Eight halophilic archaeal isolates selected based on their colony morphology and whole cell protein profiles were taxonomically classified on the basis of their morphological, physiological, biochemical properties, polar lipid and protein profiles and 16S rDNA sequences. From the 16S rDNA sequences comparisons it was established that the isolates CH2, CH3 and CHC resembled Halorubrum saccharovorum by 98.8%, 98.9% and 99.5%, respectively. There was a 99.7% similarity between the isolate CH11 and Halobacterium noricense and 99.2% between the isolate CHA1 and Haloarcula argentinensis. The isolate CH8K and CH8B revealed a similarity rate of 99.8% and 99.3% to Halococcus dombrowskii, respectively. It was concluded that the isolates named CH2, CH3 and CHC were clustered in the genus Halorubrum and that CHA1 and CH7 in the genus Haloarcula, CH8K and CH8B in the genus Halococcus and CH11 in the genus Halobacterium.
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