Rafetus swinhoei名称的历史考证与中文名更改为“黄斑巨鳖”的建议

Rafetusswinhoei是近年来才引起科学和保护界关注的极危物种,关于此物种的分类和命名,长期存在分歧和混淆。简要回顾了对R．swinhoei的科学认识过程,并对古籍进行考证后认为,中国古代所说的“鼋”,本应指此种而非Pdochelyscantorii。鉴于R．swinhoei已有的诸多中文名各自存在一定缺陷．建议采用中文名“黄斑巨鳖”。     

植物细胞多倍体诱导实验方法的改进

从植物多倍体诱导实验材料处理的方法上,介绍了改进植物多倍体诱导实验的技术,提高了多倍体细胞的分裂指数。实验用0．1％和0．01％浓度的秋水仙素溶液分别处理大蒜根尖24h、36h、48h、72h,进行多倍体诱导,再在清水中分别培养0h、12h、24h、36h,结果表明经清水培养的多倍体细胞分裂指数高于对照：0．01％浓度的秋水仙素处理的多倍体细胞分裂指数高于0．1％多倍体细胞分裂指数。     

An Iris-Like Mechanism of Pore Dilation in the CorA Magnesium Transport System

Magnesium translocation across cell membranes is essential for numerous physiological processes. Three recently reported crystal structures of the CorA magnesium transport system revealed a surprising architecture, with a bundle of giant α-helices forming a 60-Å-long pore that extends beyond the membrane before widening into a funnel-shaped cytosolic domain. The presence of divalent cations in putative intracellular regulation sites suggests that these structures correspond to the closed conformation of CorA. To examine the nature of the conduction pathway, we performed 110-ns molecular-dynamics simulations of two of these structures in a lipid bilayer with and without regulatory ions. The results show that a 15-Å-long hydrophobic constriction straddling the membrane-cytosol interface constitutes a steric bottleneck whose location coincides with an electrostatic barrier opposing cation translocation. In one of the simulations, structural relaxation after the removal of regulatory ions led to concerted changes in the tilt of the pore helices, resulting in iris-like dilation and spontaneous hydration of the hydrophobic neck. This simple and robust mechanism is consistent with the regulation of pore opening by intracellular magnesium concentration, and explains the unusual architecture of CorA.     

Pairwise Variable Selection for High‐Dimensional Model‐Based Clustering

Summary Variable selection for clustering is an important and challenging problem in high‐dimensional data analysis. Existing variable selection methods for model‐based clustering select informative variables in a “one‐in‐all‐out” manner; that is, a variable is selected if at least one pair of clusters is separable by this variable and removed if it cannot separate any of the clusters. In many applications, however, it is of interest to further establish exactly which clusters are separable by each informative variable. To address this question, we propose a pairwise variable selection method for high‐dimensional model‐based clustering. The method is based on a new pairwise penalty. Results on simulated and real data show that the new method performs better than alternative approaches that use ?₁ and ?_∞ penalties and offers better interpretation.     

Liquid-liquid phase separation of a monoclonal antibody and nonmonotonic influence of Hofmeister anions

Liquid-liquid phase separation was studied for a monoclonal antibody in the monovalent salt solutions of KF, KCl, and KSCN under different pH conditions. A modified Carnahan-Starling hard-sphere model was utilized to fit the experimental data, establish the liquid-liquid coexistence curve, and determine antibody-antibody interactions in the form of T_c (critical temperature) under the different solution conditions. The liquid-liquid phase separation revealed the complex relationships between antibody-antibody interactions and different solution conditions, such as pH, ionic strength, and the type of anion. At pH 7.1, close to the pI of the antibody, a decrease of T_c versus ionic strength was observed at low salt conditions, suggesting that the protein-protein interactions became less attractive. At a pH value below the pI of the antibody, a nonmonotonic relationship of T_c versus ionic strength was apparent: initially as the ionic strength increased, protein-protein interactions became more attractive with the effectiveness of the anions following the inverse Hofmeister series; then the interactions became less attractive following the direct Hofmeister series. This nonmonotonic relationship may be explained by combining the charge neutralization by the anions, perhaps with the ion-correlation force for polarizable anions, and their preferential interactions with the antibody.     

四川省遂宁地区吸烟人群的城乡对比

目的:了解四川省遂宁地区城乡自然人群中吸烟者的分布特征,比较城市及农村的吸烟人群在吸烟状况等方面的差异,为今后在该地区的不同人群中开展戒烟干预活动提供基础数据。方法:采用访谈和问卷调查相结合的形式,对四川省遂宁市下辖的五区城乡常住人口进行随机抽样。被调查者年龄范围为18岁至65岁。调查项目包括:一般情况、吸烟率、吸烟量、戒烟意愿和戒烟原因等。结果:从总体上看,男性吸烟率高于女性,文化程度越高在吸烟者中所占比例越小。城乡之间有统计学显著意义的差异如下:1.农村人群的吸烟率高于城市人群(男性:农村64.7%,城市45.7%;女性:农村4.6%,城市3.1%);2.农村吸烟群体的文化程度明显低于城市;3.农村吸烟者的日平均吸烟量高于城市吸烟者;4.农村吸烟者的烟龄比城市吸烟者烟龄长;5.城乡之间的戒烟原因各自不同。结论:城乡之间的吸烟者有着各自不同的特征和吸烟情况,在开展戒烟或控烟等宣称防治工作时应针对不同群体有不同的工作策略与方法。     

中医药外治法在腰椎管狭窄症中的应用

腰椎管狭窄症是由于腰椎的骨与软组织因某种原因而发生形态与组织结构方面的变化,造成椎管容积变小,导致脊神经根受到机械性压迫而出现特有的临床症状的一种疾病。本文拟通过对近年来腰椎管狭窄症的研究文献的分析、总结,从针刺、推拿、注射、牵引等对腰椎管狭窄症的中医药外治现状进行总结,旨在指导临床治疗。     

Activation of gibberellin 2-oxidase 6 decreases active gibberellin levels and creates a dominant semi-dwarf phenotype in rice （Oryza sativa L.）

Gibberellin (GA) 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs (GA3 or GA4) can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs (GA12 and/or GA53) as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding.     

Efficient production of omega-3 fatty acid desaturase (sFat-1)-transgenic pigs by somatic cell nuclear transfer

Omega-3(ω-3) fatty acid desaturase transgenic pigs may improve carcass fatty acid composition. The use of transgenic pigs is also an excellent large animal model for studying the role of ω-3 fatty acids in the prevention and treatment of coronary heart disease and cancer. Transgenic pigs carrying synthesized fatty acid desaturase-1 gene (sFat-1) from Caenorhabditis briggsae by somatic cell nuclear transfer (SCNT) were produced for the first time in China. Porcine fetal fibroblast cells were transfected with a sFat-1 expression cassette by the liposome-mediated method. Transgenic embryos were reconstructed by nuclear transfer of positive cells into enucleated in vitro matured oocytes. A total of 1889 reconstructed embryos were transferred into 10 naturally cycling gilts. Nine early pregnancies were established, 7 of which went to term. Twenty-one piglets were born. The cloning efficiency was 1.1% (born piglets/transferred embryos). The integration of the sFat-1 gene was confirmed in 15 live cloned piglets by PCR and Southern blot except for 2 piglets. Expression of the sFat-1 gene in 12 of 13 piglets was detected with RT-PCR. The data demonstrates that an efficient system for sFat-1 transgenic cloned pigs was developed, which led to the successful production of piglets expressing the sFat-1 gene.     

Extrapolating non-target risk of Bt crops from laboratory to field

The tiered approach to assessing ecological risk of insect-resistant transgenic crops assumes that lower tier laboratory studies, which expose surrogate non-target organisms to high doses of insecticidal proteins, can detect harmful effects that might be manifested in the field. To test this assumption, we performed meta-analyses comparing results for non-target invertebrates exposed to Bacillus thuringiensis (Bt) Cry proteins in laboratory studies with results derived from independent field studies examining effects on the abundance of non-target invertebrates. For Lepidopteran-active Cry proteins, laboratory studies correctly predicted the reduced field abundance of non-target Lepidoptera. However, laboratory studies incorporating tri-trophic interactions of Bt plants, herbivores and parasitoids were better correlated with the decreased field abundance of parasitoids than were direct-exposure assays. For predators, laboratory tri-trophic studies predicted reduced abundances that were not realized in field studies and thus overestimated ecological risk. Exposure to Coleopteran-active Cry proteins did not significantly reduce the laboratory survival or field abundance of any functional group examined. Our findings support the assumption that laboratory studies of transgenic insecticidal crops show effects that are either consistent with, or more conservative than, those found in field studies, with the important caveat that laboratory studies should explore all ecologically relevant routes of exposure.