保护地桃花芽分化观察

2000年6月到10月对保护地桃品种早醒艳桃的花芽进行取材,采用扫描电镜技术和制作石蜡切片系统地研究了保护地桃花芽分化的过程。结果表明:保护地桃花芽分化时间从7月中旬到9月下旬,7月末到9月中旬是早醒艳桃花芽集中分化期。研究发现花芽分化与温度、不同类型枝条、同一枝条不同节位以及营养物质积累有密切关系。     

蜜蜂(Apis mellifera)腺苷酸转移载体基因cDNA的电子克隆

 以果蝇腺苷酸转移载体基因cDNA序列为信息探针,对蜜蜂EST数据库进行同源检索筛选,克隆了蜜蜂腺苷酸转移载体基因(Am　ant)的cDNA序列(GenBank登记号为AY332626),该基因全长1 251bp。经RT-PCR克隆、序列分析验证,结果表明与电子克隆序列完全一致;该基因具有完整的开放阅读框架(ORF),编码蛋白为300个氨基酸,通过对人、果蝇、家蚕及烟草天蛾的腺苷酸转移载体蛋白序列比较,发现该基因具有高度的保守性;说明根据物种间同源基因序列,进行跨物种EST数据库的同源检索筛选、拼接,是基因克     

Analysis of differential protein expression during the early stage of in vitro tuberization in taro

Tuberization is a complex and multilevel developmental process. Many important metabolic changes in the early stage of tuberization are crucial to the tuber differentiation and development. In this study, we attempted to identify proteins differentially expressed in the early stage of in vitro tuberization in taro (Colocasia esculenta var. antiquorum) by two-dimensional polyacrylamide gel electrophoresis (2-DE) and mass spectrometry (MS). Protein samples from shoot tips cultured in 8% sucrose media at 0, 2, 4, 6 and 8 d were separated with 2-DE. A total of 13 differentially expressed proteins were analyzed with MS. Four proteins via, glyceraldehyde-3-phosphate dehydrogenase, alcohol dehydrogenase, chloroplast protein synthesis elongation factor (EF-Tu), and ankyrin repeat protein HBP1 were successfully identified during in vitro tuberization of taro. This implies that important metabolic changes, including sucrose metabolism, signal transduction and cell defense, occurred in the early stage of in vitro tuberization in taro.     

笼养孟加拉成年虎与亚成虎白昼行为的差异研究

2005年12月至2006年8月,采用瞬时扫描取样法和全事件取样法,对云南野生动物园内7只孟加拉虎行为进行了初步观察。结果表明,在观察期内,笼养孟加拉虎白昼行为时间分配上成年虎与亚成年虎之间存在一定差异,即成年虎的睡眠多于亚成年虎的睡眠;成年虎的卧息、走动、摄食和其他行为少于亚成年虎的卧息、走动、摄食和其他行为。活动节律上有一定的相似性,但也存在差异,不同年龄之间卧息和走动出现两个高峰,睡眠出现一个高峰,但亚成年虎的睡眠较为集中。     

珠美海棠叶片离体培养与植株再生

将珠美海棠试管苗叶片接种于附加NAA0.3 mg·L-1和不同体积分数的6-BA(1.0～6.0 mg·L-1)的MS培养基中进行离体培养,结果表明,6-BA为1.0～3.0 mg·L-1的处理芽再生率为6.7%～31.8%,而根的再生率为26.7%～28.3%.6-BA为4.5和6.0 mg·L-1处理芽再生率分别高...     

Subacute chlorpyrifos-induced oxidative stress in rat erythrocytes and the protective effects of catechin and quercetin

This study examined the effects of chlorpyrifos in the rat erythrocyte antioxidant system and evaluated the ameliorating effects of catechin and quercetin on the oxidative damage induced by chlorpyrifos. Sexually mature male Wistar rats were given chlorpyrifos (5.4 mg/kg, 1/25 of the oral LD₅₀), catechin (20 mg/kg), quercetin (20 mg/kg), catechin plus chlorpyrifos, and quercetin plus chlorpyrifos daily via gavage for four weeks. No statistical differences were found in the catechin-only and quercetin-only groups compared with the control group. By the end of the fourth week, chlorpyrifos alone increased the levels of malondialdehyde (MDA) and decreased superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities compared with the control group in rat erythrocytes. In the catechin-plus-chlorpyrifos and quercetin-plus-chlorpyrifos groups, there were statistically significantly decreased MDA levels and increased SOD, CAT, and GPx activities compared with the chlorpyrifos-only group. Thus, it appears that catechin and quercetin ameliorate chlorpyrifos-induced oxidative stress in rat erythrocytes in vivo.     

Mycorrhiza induced resistance in potato plantlets challenged by Phytophthora infestans

Biological control of soil-borne pathogens by arbuscular mycorrhizal (AM) fungi has been repeatedly demonstrated. However, their role in the control of above-ground hemibiotrophic pathogens is less conclusive. Here, we investigated in vitro the impact of an AM fungus on Phytophthora infestans in potato plants. The leaf infection index was decreased in mycorrhizal potato plants. Real-Time Quantitative PCR revealed the induction of two pathogenesis related genes (PR1 and PR2) in the leaves of mycorrhizal plants shortly after infection with P. infestans. These results suggested a systemic resistance in mycorrhizal plants, related to the priming of the two PR genes in potato.     

Rice genetic diversity at farm and village levels and genetic structure of local varieties reveal need for in situ conservation

Rice genetic diversity partitioning between farms, varieties and, within-variety diversity, were analysed in two villages of Maritime Guinea with contrasted agroecological conditions. One thousand and two hundred individual plants belonging to 45 accessions collected in eight farms were genotyped using 10 SSR markers. The molecular variance was evenly shared between and within accessions, while the farm effect was almost nil. Local varieties had a multi-line genetic structure. The number of multilocus genotypes was proportional to the utilisation rate of the variety in the village. The F _ST values between different accessions of each variety were significant which indicated low genetic consistency in the variety names. This varietal structure could mainly be explained by the migration phenomenon and the high varietal turnover. Compared to allelic diversity, multilocus genotypic diversity seemed to be the most suitable indicator of the quantitative distribution of diversity at different management scales (accession, farm and village). The within- and between-farm F _ST values were in the same order of magnitude. The within-farm diversity was not farm-specific but quantitatively high, i.e. up to 50% of the total genotypic diversity of a given village. Given the relative importance of the within-variety diversity, the in situ approach stands out as the most effective solution. As farms do not host specific diversity the in situ approach could be implemented by working with a small number of farms.     

microRNA-let-7家族在约克夏猪甲状腺生长发育过程中的表达分析

miR-let-7广泛参与动物组织器官发育调控,是研究猪甲状腺发育的重要候选miRNAs。为了研究miR-let-7家族在约克夏猪(Sus scrofa)甲状腺生长发育过程中的作用,本实验一方面通过对不同发育阶段(胚龄105,出生后60、90、150日龄)的猪甲状腺组织切片进行苏木精-伊红染色(hematoxylin-eosin staining,HE),研究甲状腺发育形态学的变化;另一方面,采用原位杂交(in situ hybridization,ISH)和荧光定量PCR技术鉴定miR-let-7家族在不同生长阶段(胚龄105,出生后60、90、150日龄)约克夏猪甲状腺中的表达。HE染色结果发现,甲状腺滤泡随着日龄的增加逐渐增大。原位杂交结果显示,miR-let-7主要位于甲状腺的滤泡上皮细胞中,并且let-7的表达在出生后有先减少后增加的态势。通过荧光定量PCR结果发现,在生长期随着日龄的增加,let-7d-5p、let-7f和let-7g的相对表达量逐渐上升,let-7c、let-7d-3p、let-7e和let-7i的表达先升后降。研究结果提示,约克夏猪甲状腺miR-let-7的表达直接或间接影响甲状腺激素水平的变化,在甲状腺生长发育中发挥了重要的作用,为深入研究猪的生长发育提供了一个新的思路。     

邻菲咯啉浓度对瘤胃微生物体外发酵的影响

邻菲咯啉是一种二肽酶抑制剂。本试验用体外法测定了不同浓度邻菲咯啉对瘤胃微生物发酵产气量、氨氮浓度、真蛋白含量及饲料干物质降解率的影响。结果表明 ,邻菲咯啉浓度与产气量呈直线负相关(Y=-16.75X +29.52 ,r=0.7976,P<0.05);与发酵液氨氮浓度呈直线负相关(Y= -0.5757X +3.3036,r=0.8384,P<0.05) ;与发酵管内容物真蛋白含量呈直线正相关(Y=1.35X +11.45,r=0.8423,P<0.05) ;与内容物饲料干物质降解率呈直线负相关(Y= -10.14X +55.08,r=0.9275,P<0.01)。