Mitochondrial genome sequence characteristics and phylogenetic analysis of Schizothorax argentatus / 生物工程学报

Schizothorax argentatus that only distributes in the Ili River basin in Xinjiang is one of the rare and endangered species of schizothorax in China, thus has high scientific and economic values. In this study, the complete mitochondrial genome sequence of S. argenteus with a length of 16 580 bp was obtained by high-throughput sequencing. The gene compositions and arrangement were similar to those of typical vertebrates. It contained 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding region (D-loop). The nucleotide compositions were A (30.25%), G (17.28%), C (27.20%), and T (25.27%), respectively, showing obvious AT bias and anti-G bias. Among the tRNA genes, only tRNA-Ser(GCU) could not form a typical cloverleaf structure due to the lack of dihydrouracil arm. The AT-skew and GC-skew values of the ND6 gene were fluctuating the most, suggesting that the gene may experience different selection and mutation pressures from other genes. The mitochondrial control region of S. argenteus contained three different domains, i.e., termination sequence region (ETAS), central conserved region (CSB-F, CSB-E, CSB-D, and CSB-B), and conserved sequence region (CSB1, CSB2, and CSB3). The conserved sequence fragment TT (AT) nGTG, which was ubiquitous in Cypriniformes, was identified at about 50 bp downstream CSB3. Phylogenetic relationships based on the complete mitochondrial genome sequence of 28 Schizothorax species showed that S. argenteus had differentiated earlier and had a distant relationship with other species, which may be closely related to the geographical location and the hydrological environment where it lives.

Seed quality test methods of Oldenlandia diffusa / 中国中药杂志

<p><b>OBJECTIVE</b>To optimize the testing methods for seed quality, and provide basis for establishing seed testing rules and seed quality standard of Oldenlandia diffusa.</p><p><b>METHOD</b>According to the related seed testing regulations, the seed quality of O. diffusa from different producing areas was measured.</p><p><b>RESULT AND CONCLUSION</b>The testing methods for seed of O. diffusa was established, including sampling, purity analysis, weight per 1 000 seeds, seed moisture content, seed viability and percentage germination.</p>

Quality classification criteria of Oldenlandia diffusa seeds / 中国中药杂志

<p><b>OBJECTIVE</b>To establish the quality classification criteria of Oldenlandia diffusa seeds.</p><p><b>METHOD</b>Thirty batches of O. diffusa seeds from different provenances with different collecting time were selected. And the seed germination percentage, seed purity, weight per 1 000 grains, moisture content and seed viability were determined and analyzed through SPSS 11.0 software.</p><p><b>RESULT AND CONCLUSION</b>Seed germination percentage was selected as the main index for classification, while seed purity, weight per 1 000 grains and moisture content could be used as references. The quality classification criteria of O. diffusa seeds have been initially established.</p>