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Chinese Strains (chinese + strain)
Selected AbstractsMicrosatellite markers application on domesticated silkworm and wild silkwormINSECT SCIENCE, Issue 6 2005LIE ZHANG Abstract Twenty-seven sets of simple sequence repeat (SSR) primers were developed through hybridizing of (CA)n, (CT)n and (GT)n and sequencing the positive clones in libraries constructed by using p50 silkworm strain. Of those primer pairs, 26 sets of SSR primers amplified well in two regional wild silkworm strains. Ten domesticated silkworm strains and two regional wild silkworm strains were used for comparing the polymorphisms and for constructing a phylogenetic tree employing the UPGAM method. The result showed that the genetic distances within Japanese strains are closer than those of Chinese strains. And this result also implies that Japanese strains diverged from domesticated silkworm later than Chinese strains. According to the clustering result, the domesticated silkworm is firstly clustered in one class, but could be classified into two groups. Within a strain, the individual polymorphism of wild silkworm was significantly higher in abundance than those of domesticated silkworm. The S SR primers of domesticated silkworm could be used in genetic studies for wild silkworm. [source] Structural characteristics of the cag pathogenicity island and its significance in the classification of Chinese strains of Helicobacter pyloriJOURNAL OF DIGESTIVE DISEASES, Issue 2 2002Jiong LIU OBJECTIVE: To investigate the structural characteristics of the cag pathogenicity island (PAI) and its significance in the classification in Chinese strains of Helicobacter pylori. METHODS: In 107 H. pylori strains isolated from Chinese patients, cagA, cagI, cagII, the cagI,cagII junction and IS605 were studied by using the polymerase chain reaction. RESULTS: The positive rates in Chinese H. pylori strains were 95.3% for cag PAI, 92.5% for cagA, 86.9% for cagI and 66.4% for cagII. There was no statistical difference among H. pylori strains from chronic gastritis, peptic ulcers or gastric carcinoma in the detectable rate of cag PAI, cagA, cagI or cagII (P > 0.05). Of the cag PAI-negative strains, four came from cases of chronic gastritis and one from a patient with cardiac cancer. The products of the cagI,cagII junction were found in only five strains. The continuous cag PAI was much more common in duodenal ulcers than in chronic gastritis (P < 0.01). The positive rates of cagI and cagII were markedly different in chronic gastritis (P < 0.05). One strain of H. pylori tested positive for cagA but negative for other regions of the cag PAI. IS605 was less common in duodenal ulcers than in chronic gastritis (P < 0.05). The amplified fragment of IS605 in one strain from a gastric carcinoma was approximately 1580 bp in size, which was much longer than that in other strains. CONCLUSION: Our results indicate that the cag PAI is very common in Chinese strains of H. pylori. The structural variety of the cag PAI might be related to the virulence of H. pylori. It is suggested that H. pylori may be classified into different virulence groups according to differences in the structure of the cag PAI. [source] Genetic Diversity: Geographical Distribution and Toxin Profiles of Microcystis Strains (Cyanobacteria) in ChinaJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 3 2007Zhong-Xing Wu Abstract Twenty strains of Microcystis Kütz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of cpcBA-IGS nucleotide sequence, the derived neighbor-joining (NJ) and maximum parsimony (MP) trees indicate that these strains of Microcystis can be divided into four clusters. The strains from south, middle and north region of China formed distinct lineages, suggesting high diversity and a geographical distribution from south to north locations. Moreover, the results being indicating high variable genotypes of the strains of the Microcystis strains from the same lake show that there is high diversity of Microcystis within a water bloom population. Comparing the results of the present study with those reported for compared with 43 strains of Microcystis from other locations, also reveals Chinese strains have high similarity with those from regions in the North Hemispherical. This suggests that the Microcystis strains in the world might have a geographical distribution. Analysis of 30 strains using the primers MCF/TER and TOX2P/TOX2M showed that there was no correlation between the gene of cpcBA-IGS and the presence of mcy. Toxic strains were founded to be predominant in different water bodies throughout China. [source] | ||||||||||