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Protozoa of the genus Acanthamoeba are organisms that can be generally found in the environment. The focus of this study is the detection of the presence of
Acanthamoeba in different water sources and samples taken from airconditioning units. The identification of Acanthamoeba isolates was based on the morphology of cysts and trophozoites as well as PCR amplification with a genus specific primer
pair JDP1 and JDP2. Growth characteristics and temperature tolerance were monitored. The pathogenic potential was tested in
vitro on Vero cell cultures. Genotype identification was based on the sequencing of the GTSA.B1 PCR amplimer of 18S ribosomal
DNA. The data obtained revealed that the isolates belong to T3 and T4 genotypes. One T3 and one T4 isolate contain a group
I intron. The 933 base pair intron found in a genotype T4 isolate is considerably larger compared to formerly described introns
of Acanthamoeba griffini (genotype T3) and A. Lenticulata (genotype T5). This is the first report detailing the environmental distribution of the Acanthamoeba genotypes in the region of Bratislava, Slovakia. 相似文献
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The repressor gene c
II of the L phage was cloned into plasmid pHC624 and expressed in E. coli. Two separate binding affinities for L phage DNA were identified during fractionation of protein extract of that strain. The activity that salts out in low concentration of ammonium sulphate belonged to the repressor, the activity that salts out in high concentrations of (NH4)2SO4 was proved to be of E. coli origin. Binding sites for the two proteins are located on different fragments of the L phage genome. 相似文献
205.
Roberto de la Fuente Marcia Manterola Alberto Viera María Teresa Parra Manfred Alsheimer Julio S. Rufas Jesús Page 《Genetics》2014,197(4):1137-1151
Telomeric DNA repeats are key features of chromosomes that allow the maintenance of integrity and stability in the telomeres. However, interstitial telomere sites (ITSs) can also be found along the chromosomes, especially near the centromere, where they may appear following chromosomal rearrangements like Robertsonian translocations. There is no defined role for ITSs, but they are linked to DNA damage-prone sites. We were interested in studying the structural organization of ITSs during meiosis, a kind of cell division in which programmed DNA damage events and noticeable chromatin reorganizations occur. Here we describe the presence of highly amplified ITSs in the pericentromeric region of Mongolian gerbil (Meriones unguiculatus) chromosomes. During meiosis, ITSs show a different chromatin conformation than DNA repeats at telomeres, appearing more extended and accumulating heterochromatin markers. Interestingly, ITSs also recruit the telomeric proteins RAP1 and TRF1, but in a stage-dependent manner, appearing mainly at late prophase I stages. We did not find a specific accumulation of DNA repair factors to the ITSs, such as γH2AX or RAD51 at these stages, but we could detect the presence of MLH1, a marker for reciprocal recombination. However, contrary to previous reports, we did not find a specific accumulation of crossovers at ITSs. Intriguingly, some centromeric regions of metacentric chromosomes may bind the nuclear envelope through the association to SUN1 protein, a feature usually performed by telomeres. Therefore, ITSs present a particular and dynamic chromatin configuration in meiosis, which could be involved in maintaining their genetic stability, but they additionally retain some features of distal telomeres, provided by their capability to associate to telomere-binding proteins. 相似文献
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