Vegetation and Climate Variations at Taibai, Qinling Mountains in Central China for the Last 3 500 cal BP

Pollen records of two swamp sections, located at Taibai Mountain, the highest peak in the Qinling Mountains of central China, show variations of vegetation and climate for the last 3 500 cal BP. The pollen assemblage at the Foyechi and Sanqingchi sections and the surface soil pollen allowed us to reconstruct a high-altitude vegetation history at Taibai Mountain for the first time. The data indicated that there was a cold-dry climate interval between 3 500 and 3 080 cal BP and a relatively warm and wet period compared with the present from 3 080 to 1 860 cal BP. The warmest period in the late Holocene on Taibai Mountain was from 1 430 to 730 cal BP, with an approximate 2℃ increase in mean annual temperature compared with today.There was a relatively cool-dry climate interval from 730 to 310 cal BP. After 310 cal BP, a mountain tundra vegetation developed again and the position of the modern tree line was established.     

哺乳动物DMRT1基因调控区分析

dmrt1基因是迄今为止发现的第一个在种属间具有进化保守性的性别分化基因。该基因在哺乳动物的性别分化过程中发挥着重要作用。通过对哺乳动物dmrt1基因5’端和3’端调控区的分析,发现它们分别存在3个和7个同源性较高（＞ 60％）的保守区。PCR扩增得到该基因的启动子、3’端调控区及编码区,并构入表达载体转染COS-7和ST细胞,结果显示,克隆的5’端和3’端调控区都能有效引导报告基因gfp以及dmrt1基因的表达,但表达效率在不同细胞中存在较大差异,表明dmrt1的表达存在着细胞特异性及复杂的调控机制。     

Species, population and age diversity in cell resistance to adhesion of Neisseria meningitidis serogroups A, B and C

The variation of cell adherence of meningococci serogroups A, B and C and influenza viruses was investigated in 11 animal species and in humans of different age groups (1st, 2nd, 3rd and 4th weeks; 2nd-3rd months; 4th-12th months, 2nd-3rd years; and 18th-60th years of life) as well as in women during pregnancy (17th-36th weeks) and childbirth. Red blood cells of all animals tested as well as of human newborns were absolutely resistant to attachment of meningococci. In neonatal and the later periods the human cells become far differently sensitive individually to meningococcal adhesion. In contrast, the viral adhesion was characterized by different individual cell sensitivity in all age groups tested. Pregnancy and childbirth did not influence the women's cell sensitivity to adhesion of Neisseria meningitidis. Different receptors are involved in interactions of human cells with influenza viruses and meningococci. The function of meningococcal receptors on human cells develops during postnatal ontogenesis. The variations express both specific (genetic) and ontogenetic (individual) differences in natural resistance to meningococcal infection.     

中华蜜蜂上颚腺的组织结构及其胚后发育

【目的】上颚腺（mandibular gland）是昆虫重要的外分泌腺,它产生的化学物质在昆虫的种内信息交流中起重要的作用。本研究目的在于了解中华蜜蜂Apis cerana cerana上颚腺的组织结构以及胚后发育特点。【方法】本研究通过组织形态学、BrdU免疫组织化学等技术,对中华蜜蜂上颚腺的结构和发育过程进行了比较研究。【结果】中华蜜蜂的上颚腺在不同级型间差异显著,蜂王的面积最大,工蜂较小,而雄蜂退化。上颚腺出现在末龄幼虫到预蛹阶段,细胞分裂活动的高峰期发生在蛹发育的第1天,随后分裂细胞数减少,并一直持续到蛹发育的第6天结束。在上颚腺发育早期,由分泌细胞分化的内膜就已经出现,并一直保持到成虫。【结论】本研究为昆虫上颚腺的发育和功能研究提供了理论基础。     

Micronucleus induction in mouse polychromatic erythrocytes by an X-ray contrast agent containing iodine

In this article, the authors report the results of in vivo studies on bone marrow polychromatic erythrocytes (PCE) from mice treated with Urografina?292 (a mixture of sodium amidotrizoate and meglumine amidotrizoate) and with purified sodium amidotrizoate and meglumine amidotrizoate separately or in combination at the same ratio and concentration as that of the highest dose of Urografina?292 used in the experiment. The results showed that Urografina?292 significantly increased the frequencies of micronucleated polychromatic erythrocytes (MNPCEs) in both male (p=0.0082 and p=0.0062) and female (p=0.0350 and p=0.0101) mice treated with doses of 14.3 and 20.0 ml/kg body weight, respectively. When lower doses were used (5.7 and 8.6 ml/kg body weight), the treated mice did not show any significant increase in the frequencies of MNPCEs compared with the negative control group. The same result was observed for both male and female animals treated with purified sodium amidotrizoate and meglumine amidotrizoate separately or in combination. In addition, there was a significant positive correlation between the Urografina?292 doses used and the frequency of micronuclei. These results supported the hypothesis that small amounts of aryl amines present in all X-ray contrast agents containing diatrizoate and closely related triiodobenzoates were responsible for genotoxicity. The frequencies of PCEs in treated animals were determined to estimate the toxicity of Urografina?292, sodium amidotrizoate, and meglumine amidotrizoate to bone marrow, and the results indicated that they did not show any significant difference compared with the negative control group. The fact that mutagenic agents are also generally carcinogenic contributes to the concern with regard to the possible long-term risks of these agents in case of patients who are exposed to iodine-containing X-ray contrast agents during radiodiagnostic procedures.