Universal two-dimensional labelled probe-mediated melting curve analysis based on multiplex PCR for rapid typing of Plasmodium in a single closed tube

Currently, malaria is still one of the major public health problems commonly caused by the four Plasmodium species. The similar symptoms of malaria and the COVID-19 epidemic of fever or fatigue lead to frequent misdiagnosis. The disadvantages of existing detection methods, such as time-consuming, costly, complicated operation, need for experienced technicians, and indistinguishable typing, lead to difficulties in meeting the clinical requirements of rapid, easy, and accurate typing of common Plasmodium species. In this study, we developed and optimized a universal two-dimensional labelled probe-mediated melting curve analysis (UP-MCA) assay based on multiplex and asymmetric PCR for rapid and accurate typing of five Plasmodium species, including novel human Plasmodium, Plasmodium knowlesi (Pk), in a single closed tube following genome extraction. The assay showed a limit of detection (LOD) of 10 copies per reaction and could accurately distinguish Plasmodium species from intra-plasmodium and other pathogens. Additionally, we proposed and validated different methods of fluorescence quenching and tag design for probes that are suitable for UP-MCA assays. Moreover, the clinical performance of the Plasmodium UP-MCA assay using a base-quenched universal probe was evaluated using 226 samples and showed a sensitivity of 100% (164/164) and specificity of 100% (62/62) at a 99% confidence interval, with the microscopy method as the gold standard. In summary, the UP-MCA assay showed excellent sensitivity, specificity, and accuracy for genotyping Plasmodium species spp. Additionally, it facilitates convenient and rapid Plasmodium detection in routine clinical practice and has great potential for clinical translation.     

Genomic analyses reveal natural selection on reproduction related genes between two closely related Populus (Salicaceae) species

Identifying the factors that cause reproductive isolation and their relative importance in species divergence is crucial to our understanding of speciation processes. In most species, natural selection is commonly considered to play a large role in driving speciation. Based on whole genome re-sequencing data from 27 Populus alba and 28 Populus adenopoda individuals, we explored the factors related to reproductive isolation of these two closely related species. The results showed that the two species diverged ~5–10 million years ago (Ma), when the Qinghai–Tibet Plateau reached a certain height and the inland climate of the Asian continent became arid. In highly differentiated genomic regions, the relative divergence (F_ST) and absolute divergence (d_xy) were significantly higher than the genomic background, θπ and shared polymorphisms decreased whereas fixed differences increased, which indicated that natural selection played a key role in the reproductive isolation of the two species. In addition, we found several genes that were related to reproduction that may be involved in explaining the reproductive isolation. Using phylogenetic trees resolved from haplotype data of Populus tomentosa and P. adenopoda, the maternal origin of P. tomentosa from P. adenopoda was likely to be located in Hubei and Chongqing Provinces.     

SEQUENCES OF LLANDOVERIAN CHITINOZOANS IN YANGZl REGION

This paper is dedicated as a token of homage and gratitude to Prof. Mu. En-zhi, the nestor in the field of graptolite studies, who introduced us chitinozoan studies with constant supports in many ways, and who died on 8th April, 1987. The Palaeontological Society of China has decided to publish a specieal volume in memory of this outstanding scientist.     

生长特性差别的胃癌MGC803细胞亚系间细胞骨架、细胞通讯与癌基因表达的比较研究

肿瘤细胞表型差异是临床药物敏感性、抗原性、转移性、潜伏性和进展速度等差异的主要原因。为了弄清恶性表型差别的表现、相关性及调节机理、我们从胃癌MGC 803系分离了单细胞亚系,各亚系按克隆过程的时间差别归纳分组,选快组M 17、中组M 6和慢组M 3进行比较。软琼脂生长实验表明三者的恶性程度有显著差别;M17恶性度最高,M3最低,M6居中。与其它表型联系比较,证明细胞生长速度、细胞微丝、微管骨架破坏及细胞通讯功能抑制都与锚着不依赖性生长的恶性特征有平行相关性。同时,M 17和M 3原癌基因表达有明显差别。     

超氧化物歧化酶模拟化合物的生物活性研究

根据天然超氧化物歧化酶(SOD)活性部位结构合成了含苯并咪唑的5种配体及其32种分别含Cu（Ⅱ）、Fe（Ⅲ）、Mn（Ⅱ）、Co（Ⅱ）的模拟化合物.经光谱、电化学测试证明这些化合物具有拟S3D活性,其50％抑制率浓度（IC50）为10-6～10-8mol·L-1,催化超氧离子自由基（O-·2）歧化的反应速率常数kq为106～108mol-1·L·s-1.同时观察到几种模拟化合物有抗肿瘤活性或增强水稻抗寒性.     

邻二氮菲－Fe2＋氧化法检测H2O2／Fe2＋产生的羟自由基

报告检测H₂O₂/Fe^2＋所产生羟自由基的新方法. 羟自由基氧化反应后, 邻二氮菲-Fe^2＋的A₅₃₆明显下降, 且△A₅₃₆与邻二氮菲, FeSO₄及H₂O₂呈量效关系, 随反应时间延长, △A₅₃₆依幂函数规律上升. 此法试验结果表明, 甘露醇, 抗坏血酸及硫肥清除羟自由基作用呈明显的量效关系.