峨眉山藏猕猴雄—婴社会行为的补充观察

藏猕猴 (Macaca thibetana) 雄—婴行为的补充数据收集于1997年1～9月、覆盖了整个出生季节和半个交配季节. 分别用1分钟点取样和5分钟事件取样收集雄婴照料(怀抱+接近)和雄—婴—雄三边作用 (triad) 的数据. 焦点动物为两个猴群中的8个婴儿. 数据处理结果表明: ①雄—婴照料集中在4.5～18周龄, 而20周龄内的婴儿平均有7.9％的时间受到雄性照料(雄9.6％, 雌5.6％); ②雄性婴儿较雌性接受的照料偏多, 但同性个体间无差异; ③雄性照料的强度随行为者社会等级的升高而增大;④婴儿介入 triad的频次与其接受照料的强度正相关. 考虑到藏猕猴繁殖单位中非优势雄猴的效配机会极少, 结果③、④支持了先前关于性/新选择介入了藏猕猴猴雄—婴行为进化的结论. 然而, 因为结果②不支持严格的“父—子”照料假设, 这种介入只具有模糊的统计学意义。

翻译速率与蛋白质二级结构的关系

统计分析了人的119种蛋白质和大肠杆菌的92种蛋白质密码子翻译速率和蛋白质二级结构的关系。据 二密码子片段在不同二级结构中的频数分布，我们发现人和大肠杆菌中翻译速率与蛋白质二级结构之间有一定 关系:高翻译速率时倾向编码。螺旋、不倾向编码线团(coil);低翻译速率时倾向编码线团、不倾向编码。螺旋;R 折叠结构则随翻译速率表现出明显的振荡。同时，密码子的使用在不同片段内一般也是不均匀的:在。螺旋片段 内，结构尾部偏向使用高翻译速率密码子;中部倾向使用中翻译速率密码子;而头部使用的密码子翻译速率偏 低。这样的倾向性不大可能归结为随机起伏的影响。

RESERPINE IMPAIRS SPATIAL WORKING-MEMORY PERFORMANCE IN MONKEYS - REVERSAL BY THE ALPHA-2-ADRENERGIC AGONIST CLONIDINE

Repeated daily treatment with the catecholamine-depleting agent, reserpine, dramatically reduced performance on the delayed response task, a test of spatial working memory that depends upon the integrity of the prefrontal cortex. Delayed response performance fell from an average of 27.2/30 trials correct before reserpine treatment to an average of 20.4/30 trials correct after repeated reserpine administration. Injection of the alpha2-adrenergic agonist, clonidine (0.0001-0.05 mg/kg), to chronic reserpine-treated monkeys significantly restored performance on the delayed response task; performance after an optimal dose averaged 27.8/30 trials correct. Clonidine's beneficial effects on delayed response performance were longlasting; monkeys remained improved for more than 24 h after a single clonidine injection. The finding that clonidine is efficacious in reserpinized animals supports the hypothesis that alpha2-adrenergic agonists improve cognitive function through actions at postsynaptic, alpha2-adrenergic receptors on non-adrenergic cells. In contrast to the delayed response task, reserpine had little effect on performance of a visual discrimination task, a reference memory task which does not depend on the prefrontal cortex. These results emphasize the importance of postsynaptic alpha2-adrenergic mechanisms in the regulation of working memory,

High prevalence of HIV-1 and hepatitis C virus coinfection among injection drug users in the southeastern region of Yunnan, China

The southeastern region of Yunnan province is a key site for drug trafficking and HIV-1 infection spread from the west of Yunnan and Laos to southeastern China. To investigate the prevalence of HIV-1 infection and hepatitis C virus (HCV) coinfection among injection drug users (IDUs) in southeastern Yunnan, three cohorts of 285 addicts, including 242 IDUs and 43 oral drug users, living in the cities of Gejiu and Kaiyuan and the county of Yanshan were studied. HIV-1 and HCV infections were detected by enzyme-linked immunosorbent assay and/or polymerase chain reaction. Data on the age, sex, risk behavior, drug use history, employment, ethnic background, and marriage status were obtained by interview. The overall prevalence of HIV-1 infection was 71.9%. The rate of HCV coinfection among 138 HIV-1-infected IDUs was 99.3%. Most HIV-infected IDUs were 20 to 35 years old (86.7%) and were ethnic Han (75.9%), suggesting that the epidemic in Yunnan is no longer confined to non-Han ethnic minorities, HIV prevalence in female IDUs (81.2%) was significantly higher than in male IDUs (68.2%) (p <.05). The prevalence of HIV infection reached 68.4% after 1 year of injection drug use. Needle/syringe sharing is the major high risk factor for the spread of HIV-1 and HCV infections. Large-scale educational campaigns are urgently needed to reduce the spread of HIV and HCV infection in these regions.

The relation between translation speed and protein secondary structure

Based on the statistical analysis of 119 human and 92 E. coli proteins it was found that for both human and E. coli, the mRNA sequences consisting of tri-codon and tetra-codon with high translation speed preferably code for alpha helices more than for coils. For beta strand, the preference/ avoidance oscillates with the translation speed. Moreover, the non-homogeneous usages of tri-codon and tetra-codon with different translation speeds in a given secondary structure have also been found. These results cannot be simply explained by the effect of stochastic fluctuation.

Mass rearing of Aphidius gifuensis (Hymenoptera : Aphidiidae) for biological control of Myzus persicae (Homoptera : Aphididae)

The green peach aphid, Myzus persicae, is a major pest of tobacco, Nicotiana tabacum, in Yunnan province, China, where its control still depends on the use of insecticides. In recent years, the local government and farmers have sought to improve the biological control of this tobacco pest. In this paper, we present methods for mass rearing Aphidius gifuensis, a dominant endoparasitoid of M. persicae on tobacco plants in this region. The tobacco cultivar K326 (N. tabacum) was used as the host plant and M. persicae as the host insect. In the greenhouse, we collected tobacco seedlings for about 35 days (i.e., until the six-true-leaf stage), transferred them to 7.5-cm diameter pots, and kept these plants in the greenhouse for another 18 days. These pots were then transferred to an insectary-greenhouse, where the tobacco seedlings were inoculated with five to seven wingless adult M. persicae per pot. After 3 days, the infested seedlings were moved to a second greenhouse to allow the aphid population to increase, and after an additional 4 +/- 1 days when 182 +/- 4.25 aphid adults and nymphs were produced per pot, they were inoculated with A. gifuensis. With this rearing system, we were able to produce 256 +/- 8.8 aphid mummies per pot, with an emergence rate of 95.6 +/- 2.45%; 69% were females. The daily cost of parasite production (recurring costs only) was US$ 0.06 per 1000 aphid mummies. With this technique, we released 109 800 parasitoids in 1998, 196 000 in 1999, 780 000 in 2000, and 5 600 000 in 2001 during a 2-month period each year This production method is discussed with respect to countrywide usage in biological control and integrated control of M. persicae.

延迟投饵对厚颌鲂仔鱼的影响

在室内养殖条件下,研究厚颌鲂仔鱼的摄食、耐饥饿和恢复生长能力。试验结果表明:(1)仔鱼在孵出后2～3d开口摄食,卵黄囊在之后的2d耗尽,饥饿仔鱼在12～13日龄达到不可逆点(PNR);(2)饥饿仔鱼的初次摄食率在卵黄囊耗尽时达到最高,保持在80%以上的时间为7d;(3)仔鱼在PNR后死亡率急剧增加,PNR后第3d仔鱼全部死亡;(4)经恢复生长试验,延迟3d投饵对仔鱼的存活率影响不大,延迟3～6d投饵对仔鱼全长生长影响不大。