七姊妹山自然保护区蕨类植物区系地理及资源开发研究

运用植物区系地理分析方法对七姊妹山自然保护区的蕨类植物区系特征进行研究。科的地理区系分析表明,热带、亚热带成分高达58.3%,占主导地位。属的地理区系分析也表明了类似的趋势。种的地理区系分析表明,除了热带、亚热带成分占有较高比例外,温带分布的种也具有较高的比例,占非世界广布种的1.2%。特别是世界温带分布的种占较高比例,达24.2%,这反映了温带成分的重要地位。七姊妹山蕨类植物资源丰富,可区分为药用、观赏、食用、指示类植物等几大类。各种蕨类植物资源显示了广阔的利用前景。     

NO对盐胁迫下长春花种子萌发和幼苗生理代谢的影响

为探讨NO对盐胁迫下长春花（Catharanthus roseus）种子萌发及幼苗生长的缓解作用,在50 mmol·L^-1 NaCl胁迫下,研究了不同浓度外源NO供体硝普钠（SNP）处理对长春花种子萌发及幼苗生理代谢的影响。研究表明：盐胁迫抑制长春花种子萌发,0.1 mmol·L^-1 SNP缓解盐胁迫对长春花种子萌发和幼苗生长效果最好,显著提高种子发芽率、发芽指数、活力指数和叶片中脯氨酸（Pro）含量,降低了丙二醛（MDA）含量,0.1~0.5 mmol·L^-1 SNP下硝酸还原酶（NR）活性增强,大于0.5 mmol·L^-1 SNP加重盐胁迫伤害。适当浓度的NO可有效缓解盐胁迫对长春花种子和幼苗的伤害。     

Studies of esterase 6 in Drosophila melanogaster. XVIII. Biochemical differences between the slow and fast allozymes

Most natural populations of Drosophila melanogaster are polymorphic for two major electrophoretic variants at the esterase-6 locus. The frequency of the EST 6F allozyme is greatest in populations in warmer latitudes, whereas the EST 6S allozyme is predominant in colder latitudes. Latitudinal clines in electromorph frequencies are found on three continents. Purified preparations of the allozymes have been characterized for their pH optimum, substrate specificity, organophosphate inhibition, alcohol activation, thermal stability, and kinetic parameters. These and previous analyses of the EST 6 allozymes reveal that the two variants have differences in their physical and kinetic properties that may provide a basis for the selective maintenance of the polymorphisms and an explanation of the clinal variation observed in natural populations.      

Effect of Biotic Factors on the Spatial Distribution of Stingless Bees (Hymenoptera: Apidae, Meliponini) in Fragmented Neotropical Habitats

We recorded stingless bee colony abundance and nesting habits in three sites with different anthropogenic activities in the Soconusco region of Chiapas, Mexico: (1) agroforestry (7 hacacao crop), (2) grassland (12?ha), and (3) urban area (3?ha). A total of 67 nests were found, representing five stingless bee species, Tetragonisca angustula angustula (Lepeletier), Trigona fulviventris (Guérin), Scaptotrigona mexicana (Guérin), Scaptotrigona pectoralis (Dalla Torre), and Oxytrigona mediorufa (Cockerell). The most abundant stingless bee in each site was T. angustula angustula (>50%). The primary tree species used by the bees were Ficus spp. (Moraceae, 37.8%) and Cordia alliodora (Boraginaceae, 13.5%). The nest entrance height of T. angustula angustula (96?±?19?cm) was different than the other species, and this bee was the only one that used all different nesting sites. Volatiles analyzed by gas chromatography from pollen collected by the stingless bees differed between bee species, but were highly similar in respect to the fragrances of the pollen collected by the same species at any site. Our data indicate that T. angustula angustula experienced low heterospecific and high intraspecific foraging overlap especially in the urban site. We observed cluster spatial distribution in grassland and in agroforestry sites. In the urban site, T. angustula angustula presented random distribution tended to disperse. Trigona fulviventris was the only overdispersed and solitary species.     

贲门癌中染色体8p21-p23杂合性丢失的研究

目的 研究贲门癌中染色体8p21-p23杂合性丢失的情况。方法 采用激光捕获显微切割技术获得均质的肿瘤细胞及正常的胃粘膜细胞,多重置换扩增技术扩增捕获细胞的基因组DNA。PCR结合硝酸银染色方法分析19例贲门癌染色体8p21-p23的杂合性丢失。结果 在贲门癌中染色体8p21-p23的缺失频率非常高（63.2%）,我们确定了一个最小丢失区域. 结论 进一步明确此最小丢失区域内的抑癌基因将有助于贲门癌发生机制的阐明。     

Higher number of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> CagA EPIYA C phosphorylation sites increases the risk of gastric cancer,but not duodenal ulcer

Background  

Helicobacter pylori infection is one of the most common infections worldwide and is associated with gastric cancer and peptic ulcer. Bacterial virulence factors such as CagA have been shown to increase the risk of both diseases. Studies have suggested a causal role for CagA EPIYA polymorphisms in gastric carcinogenesis, and it has been shown to be geographically diverse. We studied associations between H. pylori CagA EPIYA patterns and gastric cancer and duodenal ulcer, in an ethnically admixed Western population from Brazil. CagA EPIYA was determined by PCR and confirmed by sequencing. A total of 436 patients were included, being 188 with gastric cancer, 112 with duodenal ulcer and 136 with gastritis.     

大豆生理生态特性与产量的关系

比较研究了1970s、1980s和1990s期间不同大豆 ( Glycine max (L.) Merr.)品种的生理生态特性:光合作用、蒸腾作用、气孔导度、水分利用效率、胞间CO2浓度和叶片水势,分析了各生理生态特性之间以及与产量在不同生育期的关系.研究表明光合速率和产量之间存在显著的相关关系,高产大豆同时具有高的气孔导度和水势,胞间CO2浓度则很低,特别是在鼓粒期关系更为显著.高产大豆的光合作用在鼓粒期达到最高值,光合作用日变化呈双峰曲线.在鼓粒期高产大豆的光合产物大量运往籽粒中,对于高产品种和高光效-"源"固然重要,而"流"-光合产物的合理运转和分配对产量则更为重要.     

Renal Carcinogenesis After Uninephrectomy

Nephrectomized rats have widely been used to study chronic renal failure. Interestingly, renal cell carcinoma occurred in the remnant kidney after uninephrectomy (UNX). In this study, we probed insulin-like growth factor (IGF)-1 signaling pathway in UNX-induced renal cancer. Adult male Sprague-Dawley rats were randomized into two groups: UNX rats (n = 22) and sham-operated rats (n = 12). Rats were killed at 3, 7, and 10 months. After 7 months after nephrectomy, the UNX rats developed renal cell carcinoma with increased expression of proliferating cell nuclear antigen, and 68.2% (15/22) of the animals exhibited invasive carcinoma. Western blot demonstrated significant down-regulation of IGF binding protein 3 contrasting with the up-regulation of protein kinase Cζ and Akt/protein kinase B in the renal cancer tissues. These findings indicate a unique rat model of UNX-induced renal cancer associated with enhanced IGF-1 signaling pathway.