Molecular phylogenetic relationships of China Seas groupers based on cytochrome <Emphasis Type="Italic">b</Emphasis> gene fragment sequences

The classification and evolutionary relationships are important issues in the study of the groupers. Cytochrome b gene fragment of twenty-eight grouper species within six genera of subfamily Epinephelinae was amplified using PCR techniques and the sequences were analyzed to derive the phylogenetic relationships of the groupers from the China Seas. Genetic information indexes, including Kimura-2 parameter genetic distance and T _S/T _V ratios, were generated by using a variety of biology softwares. With Niphon spinosus, Pagrus major and Pagrus auriga as the designated outgroups, phylogenetic trees, which invoke additional homologous sequences of other Epinephelus fishes from GenBank, were constructed based on the neighbor-joining (NJ), maximum-parsimony (MP), maximum-likelihood (ML) and minimum-evolution (ME) methods. Several conclusions were drawn from the DNA sequences analysis: (1) genus Plectropomus, which was early diverged, is the most primitive group in the subfamily Epinephelinae; (2) genus Variola is more closely related to genus Cephalopolis than the other four genera; (3) genus Cephalopolis is a monophyletic group and more primitive than genus Epinephelus; (4) Promicrops lanceolatus and Cromileptes altivelis should be included in genus Epinephelus; (5) there exist two sister groups in genus Epinephelus.     

乳腺癌易感蛋白2的结构和功能

乳腺癌易感蛋白2是由乳腺癌易感基因2编码的一种在维持哺乳动物细胞染色体的稳定及DNA损伤生物应答中发挥重要作用的蛋白质。文章通过介绍近几年来对乳腺癌易感蛋白2的结构研究,阐述其在双链DNA损伤修复中的作用模型及其在肿瘤抑制中的功能。     

奶牛和肉牛6个STR基因座遗传多态性研究

利用PCR技术和复合电泳银染技术检测奶牛和肉牛BM2113、BM1862、BMc701、BM2934、TGLA122、BM720等6个STR基因座的多态性分布,并计算该6个基因座的基因频率(P_i)、个体鉴别力(DP)、杂合度(H)、多态信息含量(PIC)、和非父排除概率(PE)。结果显示:6个STR基因座的基因型分布符合Hardy-Weinberg平衡,奶牛中6个STR基因座中BM2113基因座的DP、H和PIC最高,TGLA122基因座的PE最高。6个STR基因座的累积个体鉴别力(CDP)为0.99997,累积非父排除能力(CPE)为0.98827。肉牛中6个STR基因座中BM1862基因座的DP、H、PIC、PE都是最高,6个STR基因座的累积个体鉴别力(CDP)为0.99999,累积非父排除能力(CPE)为0.99578。结果表明,6个STR基因座可用于牛的遗传连锁分析、个体识别和亲子鉴定等研究领域。     

热带林下人工种植阳春砂仁的生长与果实产量动态

调查了西双版纳不同海拔热带沟谷雨林和次生林下的阳春砂仁生长和果实产量动态．结果表明,西双版纳热带林下阳春砂仁自身年龄增长、林下光照不足和旱季水分胁迫影响阳春砂仁果实产量。随种植期增加,阳春砂仁果实产量和成熟植株密度降低．当林下光照水平在全日照的35％以下时,阳春砂仁果实产量随林下日照水平变化呈线性增加(P<0．05)。沟谷下方阳春砂仁果实产量显著高于上方(P<0.05)。海拔600～1000m,由于阳春砂仁的主花期从干热季3～4月推迟到雨季5月,果实产量显著增加,沟谷雨林和次生林下阳春砂仁果实产量差异不显著。因此,在海拔800～1000m沟谷中轮歇地次生林下有计划种植阳春砂仁,代替在沟谷雨林下种植阳春砂仁,既能解决沟谷雨林下光照和当地旱季水分不足对阳春砂仁果实产量的影响,又有利于热带沟谷雨林的保护。     

Ammonia-induced structural changes of the oxygen-evolving complex in photosystem II as revealed by light-induced FTIR difference spectroscopy

Light-induced Fourier transform infrared difference spectroscopy has been applied to studies of ammonia effects on the oxygen-evolving complex (OEC) of photosystem II (PSII). We found that NH(3) induced characteristic spectral changes in the region of the symmetric carboxylate stretching modes (1450-1300 cm(-1)) of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra of PSII. The S(2) state carboxylate mode at 1365 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectrum of the controlled samples was very likely upshifted to 1379 cm(-1) in that of NH(3)-treated samples; however, the frequency of the corresponding S(1) carboxylate mode at 1402 cm(-1) in the same spectrum was not significantly affected. These two carboxylate modes have been assigned to a Mn-ligating carboxylate whose coordination mode changes from bridging or chelating to unidentate ligation during the S(1) to S(2) transition [Noguchi, T., Ono, T., and Inoue, Y. (1995) Biochim. Biophys. Acta 1228, 189-200; Kimura, Y., and Ono, T.-A. (2001) Biochemistry 40, 14061-14068]. Therefore, our results show that NH(3) induced significant structural changes of the OEC in the S(2) state. In addition, our results also indicated that the NH(3)-induced spectral changes of the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are dependent on the temperature of the FTIR measurement. Among the temperatures we measured, the strongest effect was seen at 250 K, a lesser effect was seen at 225 K, and little or no effect was seen at 200 K. Furthermore, our results also showed that the NH(3) effects on the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are dependent on the concentrations of NH(4)Cl. The NH(3)-induced upshift of the 1365 cm(-1) mode is apparent at 5 mM NH(4)Cl and is completely saturated at 100 mM NH(4)Cl concentration. Finally, we found that CH(3)NH(2) has a small but clear effect on the spectral change of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum of PSII. The effects of amines on the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra (NH(3) > CH(3)NH(2) > AEPD and Tris) are inverse proportional to their size (Tris approximately AEPD > CH(3)NH(2) > NH(3)). Therefore, our results showed that the effects of amines on the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII are sterically selective for small amines. On the basis of the correlations between the conditions (dependences on the excitation temperature and NH(3) concentration and the steric requirement for the amine effects) that give rise to the NH(3)-induced upshift of the 1365 cm(-)(1) mode in the S(2)Q(A)(-)/S(1)Q(A) spectrum of PSII and the conditions that give rise to the altered S(2) state multiline EPR signal, we propose that the NH(3)-induced upshift of the 1365 cm(-1) mode is caused by the binding of NH(3) to the site on the Mn cluster that gives rise to the altered S(2) state multiline EPR signal. In addition, we found no significant NH(3)-induced change in the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum at 200 K. Under this condition, the OEC gives rise to the NH(3)-stabilized g = 4.1 EPR signal and a suppressed g = 2 multiline EPR signal. Our results suggest that the structural difference of the OEC between the normal g = 2 multiline form and the NH(3)-stabilized g = 4.1 form is small.     

中国种子植物区系定量化研究——Ⅰ区域性种子植物区系研究实用程序工作原理(QX—系列程序)

本文根据吴征镒教授对中国种子植物属分市区类型研究结果,研制出定量化研究区域性种子植物区系的电子计算机程序,应用本程序可完成某区系的分布区类型统计分析,科属组成分析和与其它地区以共有属关系构建的相似性系数的谁知盘中计算,同时可大量节省研究人员的劳动强度和时间,对提高研究水平有一定的效果。     

棉株上烟粉虱若虫种群的垂直分布与统计方法研究

对烟粉虱Bemisiatabaci在棉花植株上的垂直分布调查发现 ,烟粉虱在棉株各部位均有分布 ,且分布极不均匀 ,统计分析表明棉株各部位间烟粉虱的种群数量存在显著的差异。棉花顶部烟粉虱的若虫数量约占全棉株若虫总量的 1 6%,通过对棉株各部位烟粉虱的若虫数量与整株若虫总量的回归分析 ,建立了相应的回归方程式