纽氏钝绥螨、尼氏钝绥螨及其猎物—桔全爪螨生态学特性的比较研究

本文从天敌与猎物的种群内禀增长力,天敌对猎物不同密度的功能反应及数值反应三个方面来评价和比较纽氏钝绥螨、尼氏钝绥螨时其猎物——枯全爪螨的控制作用。在五种温度下,两种捕食螨的种群内禀增长力都大于桔全爪螨。它们对猎物的功能反应属HollingⅡ型。尼氏钝绥螨的捕食量大于纽氏钝绥螨,在25℃时两种捕食螨捕食量最大,应用Rogers的模型能较好地对试验结果进行模拟。尼氏钝绥螨对桔全爪不同虫态的取食不存在选择效应,纽氏钝绥螨则嗜食若螨和幼螨。两种捕食螨对桔全爪螨的数值反应表明,仅供给桔全爪螨雌成螨作为食物,对两种捕食螨都不利,尤其对尼氏钝绥螨更为明显。综上所述,两种捕食螨能比较有效地控制桔全爪螨种群,当猎物密度较高时,尼氏钝绥螨控制效果优于纽氏钝绥螨,但纽氏钝绥螨控制效果优于纽氏钝绥螨,但纽氏钝绥螨田间种群数量比尼氏钝绥螨稳定。柑桔园中存在其它补充食物时对这两种捕食敌有利。     

陕南茶树栽培区域生态与地方品种分布

陕南秦巴山区是亚热带北缘地区。由于生态环境复杂,地区差异性大,茶树栽培与引种受到一定限制。大致以汉江谷地粮作区为界,南部大巴山北麓低山丘陵区为适栽区;北部秦岭南麓低山丘陵区则为次适栽区。地方茶树群体品种有7个,约由28个地方品种组成,呈斑、块状分布。     

H Efflux and Hexose Transport under Imposed Energy Status in Maize Root Tips

The relationship between changes in H⁺ flux and sugar transport in maize Zea mays L. DEA root tips have been investigated using two methods for controlling the cellular nucleotide level: (a) incubation in the presence of a glucose analog, the 2-deoxyglucose, which decreased the ATP level to less than 15% of its initial value within 60 minutes without changing the ADP and AMP levels; (b) an hypoxic treatment which also decreased the ATP level but with a concomitant rise in ADP and AMP. In both cases the rate of hexose transport was not modified until ATP had dropped to 70% of its initial value; then it decreased with the cellular ATP level. The residual uptake rate at very low ATP concentrations still represented 50% of the maximum rate with the dGlc treatment but only the diffusion rate in anoxia. H⁺ efflux was abolished in anoxia but not by the 2-deoxyglucose treatment, in spite of a lower cellular ATP concentration. Our results are consistent with an inhibition of H⁺-ATPase activity in anoxia by the high levels of cellular ADP and AMP, and provide in vivo evidence that sugar uptake is dependent upon the proton motive force rather than cellular ATP concentration. The absence of stimulation of H⁺ extrusion by ferricyanide in either normoxic or hypoxic conditions suggests that a redox system does not appear to contribute to H⁺ secretion under the conditions of this investigation.     

Acetylcholine in the posterior hypothalamic nucleus is involved in the elevated blood pressure in the spontaneously hypertensive rat

Intravenous injection of physostigmine, 40 and 80 ug/kg, in unanesthetized normotensive rats increased systolic blood pressure (SBP) by 21 +/- 3 and 42 +/- 7 mmHg. This pressor response was 80% inhibited by intracerebroventricular (icv) injection of hemicholinium-3 (HC-3), 20 ug. Simultaneous icv injection of HC-3 and choline (365 ug) prevented the inhibition of the pressor response by HC-3. In spontaneously hypertensive rats, injection of HC-3 either icv (20 ug) or bilaterally into the posterior hypothalamic nuclei (1 ug) decreased SBP by about 40 mmHg. The effect of intrahypothalamic HC-3 was completely blocked by simultaneous injection of choline (24.3 ug) into the same site. The hypotensive effect of icv HC-3 was completely blocked by icv choline (243 ug) and was inhibited up to 60% by injections of choline (24.3 ug) into the posterior hypothalamic nuclei.     

Intervention trial with selenium for the prevention of lung cancer among tin miners in Yunnan,China

This pilot study evaluated the feasibility and effectiveness of conducting a double-blind clinical trial for the prevention of lung cancer with selenium (Se) in Yunnan Tin Corporation, the People's Republic of China, where the incidence rates of lung cancer are extraordinarily high among the miners. Forty healthy miners were randomized to either 300 μg of Se in high Se malt cakes or an identical placebo of malt cakes daily for one year. Subjects consumed their usual daily diet. The low Se concentrations in plasma (0.05±0.008 μg/mL) and hair (0.442±0.085 μg/g) reflected their low dietary Se intake in the control subjects. In Se-supplemented group, the Se status was increased by 178% for serum and 194.8% for hair. The serum GSHpx activity was increased by 155.7%, whereas the lipid peroxide level was reduced by 74.5% compared to the placebo. The results of UDS assay indicated that the lymphocyte DNA damage induced by ultraviolet irradiation and carcinogen 3,4-benzpyrene could be protected by Se supplementation. Se-supplementation did not affect the liver function test (SGPT), as well as the concentrations of hemoglobin, albumin, and cholesterol. Thus, daily intake of 300 μg Se in form of Se-malt as a chemopreventive measure is safe and effective to humans with low Se status.     

PIXE determination of essential trace elements in some traditional Chinese medicines

Biological Trace Element Research - The essential trace elements in 30 traditional Chinese medicines, (24 tonics and 6 nontonics) were determined by proton-induced X-ray emission. The...     

安徽省达到芒属植物资源及其开发利用

安徽省芒属植物有3种量变种:五节芒(Miscanthus floridulus)、芒(M.sinensis var. sinensis)、紫芒(M. sinensis var. purpurascens)和荻(M. saccharifl-orus);其中紫芒为本省地理分布新记录。它们的资源量大;如全省仅连片五节芒草地即达260多万亩,一般亩产鲜草1000—2500公斤。芒属植物是利用价值很高的资源禾草:饲用价值“良等”;保持水土能力强;纤维品质优良,为制浆造纸及编织的上等原料;并可药用。最后,提出了开发利用芒属植物资源的几点建议。     

木里柠檬种子油的脂肪酸组成和果实主要营养成分的研究

本文报道,采用气相色谱(GC)分析新发现的野生木里柠檬,和栽培的尤力克柠檬种子油的8种脂肪酸成分,和用常规化学方法对比测定两种柠檬果实中的糖,有机酸和维生素C的含量。研究结果表明,木里柠檬的脂肪酸及其它营养成分与尤力克柠檬相近。     

中草药“一口钟”的原植物鉴定及其精油的化学成分

云南,四川等省市售的中草药“一口钟”为蓝桉(Eucalyptus globulus Labill.)的果实.用气相色谱-质谱-计算机联用技术、标准品迭加和毛细管保留指数定性法,对其精油的化学成分进行分析.从分离的65个成分中,鉴定出36个成分,其含量占总组成的93.80％,主要成分是别香树烯(23.37％),1.8-桉叶油素(20.81％)、金合欢醇(9.95％)、α-水芹烯(8.30％)、δ-愈创木烯(5.95％)、δ-蒎烯(4.09％)、β-水芹烯(3.43％)、α-愈创木烯(3.15％)等.     

用人DNA介导的基因转移修复中国仓鼠细胞的HPRT缺陷

 中国仓鼠卵巢细胞(CHO-K1)经N-甲基-N'-硝基-N-亚硝基胍(MNNG)诱变和6-巯基鸟嘌呤(6-TG)选择,得到稳定的次黄嘌呤磷酸核糖转移酶(HPRT)缺陷细胞株,酶活性仅为野生型的6.5％。用磷酸钙共沉淀法和电脉冲法向HPRT-细胞转移人宫颈癌细胞(HeLaS_3)基因组DNA,纠正了CHO细胞的HPRT缺陷。酶活性提高了6.9倍,达到野生型的45％。用Alu序列探针进行分子杂交,证实经过基因转移并连续传代15次以上的受体细胞中含人DNA序列。表明人的有关基因已稳定地整合到CHO细胞的染色体中。