从甜瓜子叶中提取总DNA

用分子标记方法检测甜瓜杂交种子纯度,如果从真叶中提取DNA,检测周期至少需要15d。为了缩短检测周期,我们分别以甜瓜的成熟干种子、吸胀水后“露白”种子、3d龄刚转绿子叶、6d龄子叶、9d龄子叶和12d龄子叶为材料,进行了提取总DNA的研究。结果表明:除了干种子和吸胀水后“露白”种子外,其他的材料都可以提取到DNA,但是DNA的质量因子叶日龄不同而存在很大的差异。不同日龄的子叶中,以3d龄子叶提取的DNA质量好。子叶6d龄时,提取的DNA质量次于3d龄,少量DNA开始出现降解,以后随着子叶日龄的增加,DNA降解加重。另外,与以真叶为材料提取的DNA样品相比较,子叶DNA样品中的蛋白质等杂质含量高,应增加氯仿抽提纯化次数。     

西瓜中类胡萝卜素的高效液相色谱法分析

通过高效液相色谱法对西瓜中的类胡萝卜素进行分析,采用Vydac201TP54C18色谱柱,比较2种不同流动相的检测结果,表明乙腈:甲醇:二氯甲烷=75:20:5(V:V:V)的分离效果较好;初步定性分析确定西瓜中含有7种以上类胡萝卜素。     

苜蓿育种几个问题的探讨

在对主要苜蓿遗传资源与遗传特性进行陈述的同时, 重点对苜蓿遗传特性与育种进程的关系、目前常见的育种方法以及苜蓿育种的发展现状进行了阐述,并就近年来我国在苜蓿育种领域内存在的主要问题进行了分析,旨在为今后的苜蓿育种工作提供参考依据。     

山区农业面源污染的防治途径及对策

结合重庆市地形地貌特点和山区农业面源污染发生的因子，提出山区农业面源污染的防治对策。一方面必需结合当地的自然环境条件和经济发展水平提出农业面源污染的防治规划；另一方面必需结合生态农业建设这一主线，使物质、能量在生态系统内良性循环。紧紧抓住产生农业面源污染源的因子——化肥、农药、农田秸杆、畜禽粪便、农村生活废物等，提出科学的防治和减少途径。     

兔舍内气载需氧菌和气载葡萄球菌的检测

本研究采用A ndersen-6级空气微生物样品收集器,选用血-葡萄糖-琼脂培养基为采样介质,对两个不同种兔舍环境空气中需氧菌总数和葡萄球菌总数进行了检测,并对葡萄球菌的菌群组成进行了分析。结果表明,两个兔舍内需氧菌含量分别为1.73~85.8×103CFU/m3、2.71~9.66×103CFU/m3空气,葡萄球菌含量分别为0.94~7.84×103CFU/m3、1.02~6.54×103CFU/m3空气。兔舍空气中葡萄球菌主要包括金黄色葡萄球菌、腐生葡萄球菌、表皮葡萄球菌、科氏葡萄球菌、头状葡萄球菌和马胃葡萄球菌,其中金黄色葡萄球菌的含量占葡萄球菌总数的26.3%~29.6%,其次是腐生葡萄球菌和表皮葡萄球菌。另外,还对需氧菌和金黄色葡萄球菌在A ndersen-6级收集器不同层级上的分布情况进行了统计分析,结果表明,约有56.4%的需氧菌和49%金黄色葡萄球菌分布在3~6层上,空气动力学直径(A erody-nam ic d iam eter,D ae)在6~0.2μm,它们能进入人、畜的气管、支气管,甚至细支气管,对饲养员和动物的呼吸道构成严重危害。     

The basic mechanism of increased microvascular permeability

The increased microvascular permeability appears mainly in venule during inflammation, shock, and burns. Endothelial cells play an important role in venule permeability enhancement. There are two kinds of pathway for macromolecule extravasation. One is paracellular pathway and another is transcellular pathway, which are related to the formation of endothelial gap or transcellular openings seperately. The alteration of intercellular related protein, such as occludin, claudin, zona occludens (ZO), junctional adhesion molecule (JAM), VE cadherin, catenin, integrin, etc, and the alteration of endothelial cytoskeleton, such as rearrangement of actin filament, formation of stress fiber and focal adhesion, etc, involve in the pathogenesis of increased microvascular permeability.     

中国风水侵蚀交错区分布特征分析

风水侵蚀交错带的研究 ,对景观、土地覆盖 /土地利用、全球变化等研究具有重要意义。论文以GIS技术为支撑 ,定量计算出我国风水侵蚀带。在分布特征上 ,主要分布我国北方地区 ,其中以西部沙漠 ,北部山脉沿线为重 ,这种分布与气候、地貌分界有明显联系。 49.6 %风水侵蚀复合带的降水量小于 2 0 0mm。风水侵蚀复合带的土地利用主要以草地为主 ,占 41.8% ,其次为耕地。两种类型的分布 ,草地以与其它土地利用类型交错分布为主 ;而耕地是有重心的分散分布。风水侵蚀复合带的总体侵蚀要强于全国水平。     

不同地下水位植物蒸腾耗水特性研究

在甘肃省民勤治沙站利用非称量测渗仪研究了梭梭、柠条等 10种沙区植物的蒸腾耗水特征。结果表明 ,各种植物 5a的总蒸腾量由大到小排列为 :沙枣、花棒、沙木蓼、柠条、梭梭、白皮沙拐枣 ;随植物年龄增长 ,蒸腾系数有上升的趋势 ,而蒸散系数有下降的趋势 ;在民勤沙区 6～ 9月是主要蒸腾季节 ,该时段的蒸腾量占全年蒸腾量的80 %～ 90 % ;植物的蒸腾量随年龄的增长而迅速增加 ,但增长幅度随物种不同而异。一般生长快的植物增长快 ,生长慢的植物增长慢。     

Inhibitory effects of LDL-ACM complex on subcutaneous implanted tumors in nude mice()

AIM: In order to evaluate the applicable value of LDL as a targeted vehicle for chemotherapeutic agents, we investigated and compared the inhibitory effects of LDL-ACM complex and free ACM on nude mice's subcutaneous implanted tumors derived from gastric cancer cell lines, SGC-7901 and NKM-45. METHODS: LDL-ACM complex was prepared and the tumor model of nude mice was established by subcutaneous implantation of SGC-7901 and NKM-45. Then, the groups of nude mice developed subcutaneous implanted tumors were received either LDL-ACM complex or free ACM. Subsequently, the tumor size, weight and leukemia cell counts were measured and the rates of tumor-inhibition and the survival were compared among the groups. RESULTS: The inhibitory effects of LDL-ACM complex on the tumors, especially on SGC-7901 implanted tumors were much more obvious than that of free ACM. It was also indicated that the action of LDL-ACM complex was mediated by LDL receptor. CONCLUSION: These results showed that LDL-ACM complex had significant inhibitory effects on the implanted tumors and the effect might be mediated by LDL receptor.     

Effect of cocaine on caspase-3 in myocardiac cells of male rats in different age

AIM: To study the effect of cocaine on caspase-3 in myocardiac cells of male rats in different age. METHODS: Three-week-old(n=16), six-week-old(n=16) and twelve-week-old (n=16) male Sprague-Dawley rats were all divided into control groups and experiment groups randomly, each group had eight animals, experiment groups were given cocaine hydrochloride (15 mg·kg^-1 body weight) subcutaneously daily for four weeks. The ratio of heart weight to body weight (HW/BW, mg/g) were measured. DNA fragmentation of myocardia cells was determined by gel electrophoresis, and caspase-3 activity in myocardia cells was tested by flow cytometry (FCM). RESULTS: In three experiment groups, the DNA isolated from myocardial cells displayed clear ladder pattern. The HW/BW and the caspase-3 activity were increased significantly than those of control groups (P<0.01). CONCLUSIONS: Cocaine induced apoptosis in rat myocardial cells. The increase in caspase-3 activity may be the one of important pathways related to the induction of apoptosis.