略论骆驼的耐干渴能力

荒漠水源奇缺,常有干渴威协。骆驼长期在这种自然选择下,造就出一种十分惊人的耐干渴能力,十日不饮可照常供使役,30～40日内缺水不致有生命危险。据研究认为,骆驼高度耐渴的机理主要在于:一次能饮入60～80升甚至更多的水;能饮用含盐量相当高的水;血液和体液中保存水的能力很强;能节约散热、呼吸、排尿、排粪过程中的水份消耗;有较高排泄浓缩尿的能力;可有效利用体内的代谢水;即使高度失水(达体重的30%)也能短期耐受过去。正因其耐渴能力强,所以才使人类开发利用荒漠成为可能;使大面积缺水草埸和其它家畜所不能利用的灌木类植物得到合理利用;还能在缺水条件下持续分泌稀薄的低脂肪驼乳,为沙漠旅行者提供上等饮料。     

嗜金微生物研究概况

在广泛文献检索基础上,对嗜金微生物的种属、富集黄金的机理、工业应用价值及潜力进行了概述,为进一步对其开发利用提供科学资料。     

Traditional fallows in Latin America

Traditional fallow systems of Latin America have not been extensively studied from either a socioeconomic or biophysical viewpoint. Only in the past decade have some of these systems — modified shifting cultivation in the Amazon, the bracatinga (Mimosa scabrella) fallow of southeastern Brazil, the babassu (Attalea spp.) system of the Amazon margins, and short bush fallows mostly for Phaseolus bean (the so-called frijol tapado) — received any attention. Over the past century, traditional cultivators have adopted several legumes such as Mucuna spp., Lathyrus nigrivalis, Canavalia spp., and Senna guatemalensis as green manures or managed fallows in food crop production systems, which have recently been the object of studies by social and biological scientists. Longer, monospecific fallows involving woody legumes have been studied to varying degrees. The legumes include Senna guatemalensis, Mimosa tenuiflora, and Gliricidia sepium. Systems in which crop production is alternated with animal grazing of secondary vegetation include the caatinga of Northeast Brazil, the espinales of Chile, the matorrales of northern Mexico, and the chaco of Argentina, Paraguay, and Bolivia. A classification is proposed depending on the nature of the species (woody or nonwoody) and their composition (mono- or multispecies) and land management (burned or not). Much work is still needed in more complete characterization, determination of economic importance and potential, understanding the relationships among components, studies of nutrient cycling, and verification of the effects of shorter fallow periods of these systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

Turnover of Se in adequately fed chickens using Se‐75 as a tracer

Inorganic selenium (Se) in the form of selenite is applied to livestock to avoid Se deficiency. Selenite is, however, an artificial Se source in diets of unsupplemented chickens. It is therefore hypothesized that organic Se sources, such as Se‐enriched yeast and wheat, could be a more suitable Se supply in animal nutrition, although information on the transition of Se from organic Se sources in fast‐growing chickens is scarce. In this work, chickens were fed a low Se diet (0.27 ± 0.01 mg Se/kg, Se‐enriched yeast) until 20 days of age, after which the Se concentration was increased to maximum concentration allowed by the poultry industry in Europe (0.5 p.p.m. Se). At the same time, a daily contribution of carrier‐free ⁷⁵Se tracer from labelled wheat was administered from day 20 to 27. The chickens showed S and Se homeostasis, as the concentration of S and Se in liver, blood or kidney remained about constant, and steady state of S and Se in the other organs was reached 1 day after the diet shift. The uptake of ⁷⁵Se was readily seen in all organs. After 1 week, the depuration of the ⁷⁵Se tracer was followed, and biological half‐lives and retention in individual organs were determined. The shortest biological half‐lives were observed in major metabolic organs, the liver, kidney and pancreas with half‐lives close to 4 days. There was a significant (p < 0.05) uptake in lung, brain and muscle that reached steady state when the administration of ⁷⁵Se was terminated. The half‐life of ⁷⁵Se in heart was 9 days and 7 days in blood. The longest half‐lives were observed in muscle (12 days), brain and lungs (13 days). All half‐lives were shorter than in Se deplete animals.     

曼氏无针乌贼微卫星DNA富集文库构建与鉴定

曼氏无针乌贼是我国四大海产之一,开发其微卫星标记具有重要的科研与应用价值。本研究采用FIASCO法（Fast Isolation by AFLP Sequences Containing repeats）构建了曼氏无针乌贼的（CA）n微卫星富集文库,通过PCR检测出640个阳性克隆,占所有克隆的87%,从阳性克隆中随机选取118个进行测序,序列分析发现,103个克隆含有7次以上的重复序列,其中完全的为67（65%）个,不完全的23个（22.3%）,复合的为13（12.7%）个,重复次数范围为7~59次,平均为38次。在103个序列中共42条可以设计引物,所筛选出的引物可以用于评估曼氏无针乌贼种质资源遗传多样性、遗传结构、亲子鉴定以及放流效果评估等。     

小麦富硒生产技术研究

通过国家发明专利产品——富硒增产素（ZL96107830.8）在小麦上的应用，生产出人类理想的天然富硒小麦，进而加工成品种多样的天然富硒保健食品，使硒进入食物链，实现安全、方便、经济地给人体补硒，将从根本上解决人畜缺硒状况，从而提高中华民族的健康水平，造福人类，实属一项绿色保健型农业新技术。为了生产富硒小麦，笔者以叶面喷施的方式在小麦拔节期、灌浆初期和灌浆中期喷施硒液肥，探索硒液肥对小麦籽粒硒含量的影响，结果表明：小麦籽粒中硒含量高于对照3倍左右。     

卤虫卵与空壳的分离技术

本文主要对卤虫卵加工中采用淡水比重法分离虫卵和空壳的方法进行了较为详细的论述．对近几年有关这方面的试验研究及存在的一些问题进行了概括和总结．     

富硒麦芽对链尿佐菌素诱发糖尿病大鼠糖脂代谢的影响

健康SD大鼠 72只随机分成 3组 ,正常对照组 (Ⅰ组 )和试验对照组 (Ⅱ组 )的饲料硒含量均为 0 1mg·kg-1;补富硒麦芽组 (Ⅲ组 )的饲料硒含量 0 3mg·kg-1。饲喂 5周后 ,Ⅱ、Ⅲ组用链尿佐菌素 (streptozotocin ,STZ)按每千克体重 6 0mg的剂量腹腔注射诱发糖尿病 ,Ⅰ组仅注射等剂量的缓冲液。继续饲喂 4周后观察各组大鼠抗氧化功能及糖、脂代谢变化。试验结果表明 ,补饲富硒麦芽能显著提高糖尿病大鼠胰岛素水平 ,降低血糖浓度 ;显著提高正常大鼠全血谷胱甘肽过氧化物酶 (GSH Px)活性 ,延缓糖尿病大鼠GSH Px和血浆超氧化物歧化酶活性下降趋势 ,降低血清胆固醇和甘油三酯浓度。提示补充适量的富硒麦芽 ,可增强STZ致糖尿病大鼠的抗氧化能力 ,降低血糖 ,降低脂质过氧化作用 ,改善糖、脂的代谢状态     

L-肉碱强化卤虫对鲤鱼开口苗脂肪酸组成和C/N比率的影响

【目的】研究L-肉碱强化卤虫对鲤鱼开口苗脂肪酸组成和C/N比率的影响,为鲤鱼开口苗的饲养提供参考。【方法】分别用质量浓度为0(对照),1,100,1 000 mg/L的L-肉碱强化卤虫无节幼体(Artemiasp.)12和24h,然后投喂给鲤鱼(Cyprinus carpio)开口苗,21 d后测定鱼苗的脂肪酸组成和C/N比率。【结果】投喂L-肉碱强化12 h的卤虫时,1 mg/L L-肉碱处理组鲤鱼开口苗的∑C14-24脂肪酸含量、饱和脂肪酸含量和单不饱和脂肪酸含量较对照组显著降低(P<0.05);1 000 mg/L L-肉碱处理组鲤鱼开口苗的单不饱和脂肪酸含量较对照组显著升高(P<0.05);L-肉碱对鲤鱼开口苗的多不饱和脂肪酸含量、∑n-3+∑n-6和∑DHA+EPA含量均无显著影响(P>0.05);1 000mg/L L-肉碱处理组鲤鱼开口苗的C/N比率显著低于对照组和1 mg/L L-肉碱处理组(P<0.05)。投喂L-肉碱强化24 h的卤虫时,1和100 mg/L L-肉碱处理组鲤鱼开口苗的∑C14-24脂肪酸和饱和脂肪酸含量较对照组显著降低(P<0.05),但2组之间差异不显著(P>0.05);1 000 mg/L L-肉碱处理组鲤鱼开口苗的∑C14-24脂肪酸和饱和脂肪酸含量较对照组显著升高(P<0.05);1 mg/L L-肉碱处理组鲤鱼开口苗的单不饱和脂肪酸含量较其他3组显著降低(P<0.05),多不饱和脂肪酸、∑n-3+∑n-6和∑DHA+EPA含量与对照组差异不显著(P>0.05);100 mg/L和1 000 mg/L L-肉碱处理组鲤鱼开口苗的多不饱和脂肪酸、∑n-3+∑n-6和∑DHA+EP A含量较对照组显著升高(P<0.05),且2组之间差异显著(P<0.05);1,100 mg/L L-肉碱处理组鲤鱼开口苗的C/N比率较对照组和1 000 mg/L L-肉碱处理组显著降低(P<0.05)。【结论】本试验条件下,以质量浓度100 mg/L L-肉碱强化卤虫24 h后再投喂鲤鱼开口苗,可显著改善鲤鱼开口苗的脂肪酸组成和C/N比率。     

一种做为遗传学教学的实验材料——卤虫

卤虫做为一种经济动物已广泛应用于水产养殖业中,但是做为一种遗传学教学的实验材料尚无人报道过。通过多次实验,本文作者提出了一种改进后的观察卤虫染色体形态和数目的实验方法。同时,作者还例举了各种事实表明卤虫是一种很好的遗传学教学的实验材料。