广西“恭城模式”探讨

探讨广西“恭城模式”,总结其模式特点,指出了面临的问题,并提出了一步发展的思路,对我国西部地区特别是山区实现农业的可持续发展提供借鉴作用。     

The isolation of early nuclear endosperm of <Emphasis Type="Italic">Oryza sativa</Emphasis> to facilitate gene expression analysis and screening imprinted genes

Background

Since the quality and yield of rice production depends on endosperm development, previous studies have focused on the molecular mechanism that regulates this developmental process. Recently, how this process is epigenetically regulated has become an important topic. However, the gene expression analysis and screening imprinted genes during early endosperm development remain challenging since the isolation of early endosperm has not been possible. Here, we report a procedure for the isolation of endosperm at 24 or 48 HAP (hours after pollination) during the free nuclear stage of endosperm development.

Results

This technique allows for rapid and convenient collection of pure free nuclear endosperm. Early endosperm RNA can then be extracted from the isolated endosperm cells using dynabeads. Our results showed that the quality of RNA is satisfactory for gene expression analysis and screening the parental-of-origin specific genes in early endosperm.

Conclusions

Thus, we offer a reliable method to overcome one of the major obstacles in the investigation of the molecular mechanisms of early endosperm development. Our approach can be used for accurate gene expression analysis and screening of imprinted genes, and facilitates the confirmation of endosperm-specific gene expression at the very early stages of endosperm development. This method could also be used in other species to collect early free nuclear endosperm.

     

Growth,digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp Ctenopharyngodonidella fed graded levels of dietary threonine

Background

This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp (Ctenopharyngodonidella).

Results

Weight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine (P < 0.05). Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation (P < 0.05). Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine (P < 0.05).

Conclusions

Dietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp (441.9-1,013.4 g) based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.     

Enhanced upper tropical tropospheric COS: impact on the stratospheric aerosol layer

Carbonyl sulfide (COS) is considered to be a major source of the stratospheric sulfate aerosol during periods of volcanic quiescence. We measured COS at the tropical tropopause and find mixing ratios to be 20 to 50% larger than are assumed in models. The enhanced COS levels are correlated with high concentrations of biomass-burning pollutants like carbon monoxide (CO) and hydrogen cyanide (HCN). The analysis of backward trajectories and global maps of fire statistics suggest that biomass-burning emissions transported upward by deep convection are the source of the enhanced COS in the upper tropical troposphere.     

绵羊空肠和回肠综合肌电的活动规律

空肠和回肠肌电是以峰电周期性活动为特征的综合肌电，都有３个时相。回肠的３个时相均由空肠末端移行而来     

优质香型杂交水稻宜香9303高产制种技术

宜香9303是重庆市涪陵区农科所与四川宜宾市农科所联合选育的优质香型高产杂交中籼组合,2004年3月通过重庆市审定.在重庆涪陵区大面积制种平均单产达3.4 t/hm2,高产田块达4 t/hm2.总结了其亲本特性及主要高产制种技术.     

优质高产杂交水稻新组合泸香615

泸香615是四川省农科院水稻高粱研究所用自育恢复系泸恢615与自育不育系泸香91A配组育成的迟熟杂交中籼新组合,表现米质优,产量高,抗病性较强和适应性较广。2004年通过四川省品种审定委员会审定。     

红藻分子系统学研究进展

红藻分子系统学研究进展匡梅，王素娟，曾呈奎（上海水产大学，２０００９０）（中国科学院海洋研究所，青岛２６６０７１）关键词红藻，分子系统学ＡＤＶＡＮＣＥＳＩＮＴＨＥＳＴＵＤＹＯＦＭＯＬＥＣＵＬＡＲＳＹＳＴＥＭＡＴＩＣＳＩＮＲＨＯＤＯＰＨＹＴＡ￥Ｋｕａｎ...     

超声辅助提取槟榔核多酚工艺优化及降糖活性研究

研究提取条件对槟榔核提取物中多酚含量及其体外降糖活性的影响.以槟榔核为原料,乙醇溶液为提取溶剂,利用福林-酚比色法测定槟榔核中多酚的含量,分析槟榔核提取物对α-葡萄糖苷酶和α-淀粉酶的影响,并进行工艺优化.结果 表明:超声辅助提取槟榔核多酚最佳条件为:乙醇体积分数40％,料液比1∶60(g/mL),提取温度80℃,提取...     

Vascular Endothelial (VEGF) and Epithelial Growth Factor (EGF) as Well as Platelet‐Activating Factor (PAF) and Receptors are Expressed in the Early Pregnant Canine Uterus

The aim of this study was to investigate the course of expression of platelet‐activating factor (PAF), PAF‐receptor (PAF‐R), epidermal growth factor (EGF), EGF‐R, vascular endothelial growth factor (VEGF), VEGF‐R1 and VEGF‐R2 in uterine tissue during canine pregnancy. For this purpose, 20 bitches were ovariohysterectomized at days 10–12 (n = 10), 18–25 (n = 5) and 28–45 (n = 5) days after mating, respectively. The pre‐implantation group was proven pregnant by embryo flushing of the uterus after the operation, the others by sonography. Five embryo negative, that is, non‐pregnant, bitches in diestrus (day 10–12) served as controls. Tissue samples from the uterus (placentation sites and horn width, respectively) were excised and snap‐frozen in liquid nitrogen after embedding in Tissue Tec^®. Extraction of mRNA for RT‐PCR was performed with Tri‐Reagent. In the embryos, mRNA from all factors except VEGF was detected. In the course of pregnancy, significantly higher expression of PAF and PAFR as well as VEGF and VEGFR2 during the pre‐implantation stage than in all other stages and a strong upregulation of EGF during implantation were characteristic. The course of EGF was in diametrical opposition to the course of the receptor. These results point towards an increased demand for VEGF, EGF and PAF during the earliest stages of canine pregnancy.