中国学术文献总库(CNKI)的主要功能和使用技巧

结合在线咨询服务和用户培训中积累的经验,就升级后新版的CNKI的主要功能和使用技巧进行了整理和总结.     

不同栽培密度对秋大棚黄瓜生育期及产量的影响

试验以黄瓜为材料,采用随机区组设计,研究了不同栽培密度对秋大棚黄瓜生育期及产量的影响。结果表明,当栽培密度为4000株/667m2时,产量和产值都达到最高。     

绵羊瘤胃微生物胞外蛋白酶性质的研究

本试验测定了pH、温度和EDTA对纯化的绵羊的瘤胃微生物胞外蛋白酶活性的影响,并用一已知氨基酸排列顺序的肽段(由15个氨基酸组成)作为底物,进一步测定了蛋白酶的酶切位点。结果表明,(1)纯化蛋白酶的最适pH在6.0～6.5之间,最适温度为40℃左右。(2)不同浓度的EDTA(浓度分别为1,10,25,50,75和100mM)对蛋白酶活性没有影响,因而该酶属于丝氨酸蛋白酶类。(3)纯化蛋白酶是一种内肽酶,其酶切位点在组氨酸—酪氨酸(?)、天冬氨酸—丙氨酸(?)、亮氨酸—赖氨酸(?)和(或)缬氨酸—赖氨酸(?)相连的肽键。(4)胰蛋白酶和纯化的蛋白酶虽同属丝氨酸蛋白酶类,但前者对底物具有高度的专一性,后者对底物的专一性不强,这是瘤胃内饲料蛋白质强烈降解的主要原因之     

分泌抗鸡Ig单抗杂交瘤细胞系的建立与单抗生物学特性的鉴定

从传染性法氏囊病病毒（ＩＢＤＶ）单克隆抗体（ＭｃＡｂ）杂交瘤细胞系１Ｄ１０、１Ｇ１中得到了３株能稳定分泌抗鸡免疫球蛋白（Ｉｇ）ＭｃＡｂ的杂交瘤细胞系１Ｂ７、１Ｄ７、３Ｇ６。其抗体类和亚类均属ＩｇＧ２ｂ，腹水的ＥＬＩＳＡ效价≥１∶２５６００，琼扩效价为１∶８～１∶１６。３株ＭｃＡｂ能与鸡血清中的Ｉｇ出现沉淀反应，琼扩在２４ｈ以内出现清晰的沉淀线，而不能和鸭、鸽、鹌鹑等禽类及异种动物血清出现沉淀线。纯化的鸡ＩｇＧ、ＩｇＭ经ＳＤＳ－ＰＡＧＥ后，分别用纯化并经辣根过氧化物酶（ＨＰＲ）标记的１Ｂ７、１Ｄ７、３Ｇ６单抗酶结合物进行免疫印迹试验证明，３株单抗识别的均为ＩｇＧ、ＩｇＭ分子的轻链     

阿尔泰山森林重点火险区综合治理工程效益分析

介绍了阿尔泰山实施森林重点火险区综合治理工程项目后所带来的社会、经济、生态效益,并评述了该项目对阿尔泰山的影响。     

田间小棚繁殖烟蚜茧蜂的繁蜂效果研究

研究了田间小棚繁殖烟蚜茧蜂的繁蜂效果,比较了在不同接蜂量和蚜量范围条件下的僵蚜数量及其羽化情况。接蜂量和接蜂时的蚜量是影响僵蚜数量的2个重要因素,以接蜂时的蚜量对繁蜂效果的影响更为明显。在接蜂量为蜂(♀)蚜比1∶100、蚜量范围2 000~3 000头/株的条件下,可获得较好的繁蜂效果,僵蚜的数量可达到8 000个/株以上。在繁蜂前期僵蚜的质量较高,僵蚜的羽化率可保持在90%以上,在繁蜂后期受重寄生蜂的影响,僵蚜的质量明显下降。应用田间小棚繁殖烟蚜茧蜂时,重寄生蜂是影响后期繁蜂质量的重要因素。     

4株酸奶噬菌体的分离

从上海光明乳业股份有限公司车间发酵罐中分离出4株酸奶噬菌体。1号噬菌体头部呈六角形，平均直径为95.1nm，头部剖面平均面积为8184．8nm^2，尾部的平均直径为18．3nm，平均长度为403．4nm；2号噬菌体头部呈六角形，平均直径为85．4nm，头部剖面平均面积为8046．2nm^2，尾部的平均直径为23．3nm，平均长度为549．4nm；3号噬菌体头部呈六角形，平均直径为95．5nm，头部剖面平均面积为9792．3nm^2，尾部的平均直径为19．8nm，平均长度为450．5nm；4号噬菌体头部呈六角形，平均直径为119．3nm．头部剖面平均面积为12586．1nm^2，尾部的平均直径为23．6nm，平均长度为520．5nm。     

Investigation of Cervical Patency and Uterine Appearance in Domestic Cats by Fluoroscopy and Scintigraphy

The cervical patency of six domestic female cats was monitored under sedation by infusion of contrast medium (Omnipaque) into the cranial vagina during early oestrus, mid‐oestrus, late oestrus and interoestrus or a radiopharmaceutical (^99mTc‐HSA) during mid‐ and interoestrus in a non‐ovulatory oestrous cycle. The transport of the contrast medium or the radiopharmaceutical through the cervix and within the uterine horns was observed under fluoroscopy and with the aid of scintigraphy. In three of the queens, transcervical transport of contrast medium was demonstrated in all stages of oestrus, in one queen during mid‐oestrus, late oestrus and 1 day after oestrus, and in two queens only during late oestrus. The relations between the cervical patency to the contrast medium and the oestrous behaviour, cornification of the vaginal cells and the serum oestradiol‐17β concentration were evaluated, and a relationship was found between the cervical patency and the degree of vaginal cornification. Transcervical transport of the radiopharmaceutical was observed in three queens during mid‐oestrus. When the cervix was open, hysterography under a fluoroscope and hysteroscintigraphy were performed. The fluoroscopic and scintigraphic recordings revealed the patterns of the uterine contractions during oestrus in both ascending and descending directions, and the movement of the uterine contents back and forth between the uterine horns. The hysterograms were classified according to the shape of the uterine horns and the appearance of the endometrial lining. Spiral‐shaped uterine horns with a smooth inner contour were observed in two queens, and a corkscrew appearance with irregular filling defects in the uterine lumen was shown in two queens that had developed subclinical cystic endometrial hyperplasia. These findings demonstrated that fluids or particles deposited in the cranial vagina of the cat can be transported into the uterus during some stages of the oestrous cycle. The fluoroscopic and scintigraphic techniques developed in this study may be further modified to permit more detailed studies of uterine contractile patterns and sperm transport in the feline female reproductive tract. Hysterography proved useful to diagnose uterine disease. The information on cervical patency is of value also for the development of techniques for artificial insemination in this species, and should be studied also in the ovulatory cycle.     

Reproductive roles predict sexual dimorphism in internal and external morphology of lake whitefish,Coregonus clupeaformis

Abstract – The different reproductive roles of the sexes can predict the direction and magnitude of sexual dimorphism of external and internal morphology. Males should have enlarged structures that enhance the acquisition of mating opportunities, whereas females are predicted to have enlarged organs that are associated with the production of eggs. We tested these predictions in male and female lake whitefish, a species in which both sexes have similar overall body size and shape. After controlling for body size, male lake whitefish had significantly longer jaws and pectoral and pelvic fins, larger hearts, and more muscle than females. Sexual dimorphism in relative muscle mass may be one of the most fundamental morphological differences between males and females. Females had relatively heavier livers than males. Because the liver is important for the breakdown of fats and vitellogenesis, selection should favour an enlarged liver in females for the processing of energy and the production of large numbers of eggs.