宁夏荒漠草原5种乡土植物适应性评价

开展乡土植物的适应性评价对退化草地生态修复具有重要意义。以宁夏荒漠草原的乡土植物牛枝子（Lespedeza potaninii）、草木樨状黄耆（Astragalus melilotoides）、野生沙芦草（Agropyron mongolicum）、人工繁育沙芦草和新品系沙芦草为研究对象,从农艺性状、光合特性和营养价值3个方面16项指标进行适应性评价。结果表明：牛枝子的生长速度、叶茎比、干草产量显著高于其他4种植物（P <0.05）,越冬率达到100%;3种禾本科植物的净光合速率显著高于两种豆科植物（P <0.05）,胞间CO₂浓度反之;5种植物间气孔导度与蒸腾速率差异不显著（P> 0.05）;草木樨状黄耆的粗蛋白含量显著高于其他种植物（P <0.05）,且中性洗涤纤维、酸性洗涤纤维含量较低,相对饲喂价值高。灰色关联方法综合评价发现,5种乡土植物适应性在等权关联度下呈现草木樨状黄耆>牛枝子>人工繁育沙芦草>野生沙芦草>新品系沙芦草;在加权关联度下呈现草木樨状黄耆>人工繁育沙芦草>牛枝子>野生沙芦草&...     

水牛MFSD2A基因多态性及其与产奶性状的关联分析

【目的】研究水牛主要促进因子超家族成员2a(major facilitator superfamily domain containing 2a, MFSD2A)基因多态性,并筛选与水牛产奶性状相关联的SNP。【方法】采集383头健康水牛血液DNA,利用PCR扩增和Sequenom MassARRAY飞行时间质谱技术对SNP位点进行筛选及基因型检测,并进行遗传多样性、连锁不平衡(LD)和单倍型分析,以及对不同基因型和单倍型与水牛产奶性状进行关联分析。【结果】在水牛MFSD2A基因中检出7个SNPs位点,多态信息含量(PIC)均在0.25～0.40之间,属于中度多态,除g.8290 T>C位点外,其余位点均处于Hardy-Weinberg平衡状态(P>0.05);关联分析结果表明,这7个SNPs位点与305 d产奶量均显著关联(P<0.05),且突变杂合子基因型的305 d产奶量是3种基因型中最低的,g.568 C>G和g.701 A>G位点与乳脂率显著关联(P<0.05),乳脂率从大到小依次为突变纯合子>野生纯合子>突变杂合子,g.568...     

青海省部分地区藏獒及草地鼠类弓形虫抗体间接血凝试验检测

应用间接血凝试验(IHA),对青海省部分地区的藏獒、喜马拉雅旱獭、高原鼠兔及中华鼢鼠的311份血清样品,进行弓形虫特异性抗体的检测。结果检出33份阳性血清,阳性率为10.61%。     

OSTEOCHONDROSIS IN THE LATERAL FEMORAL CONDYLES OF A HORSE

Osteochondrosis of the lateral femoral condyles was diagnosed radiographically in an 8-month-old, female Arabian horse, which had been presented with a hindlimb lameness. The diagnosis was confirmed by gross and microscopic pathology. The location of the lesions was considered unusual for osteochondrosis in the horse.     

高非蛋白氮利用能力酵母菌的筛选与诱变

蛋白质饲料资源短缺一直是制约着中国饲料工业健康平稳发展的瓶颈问题之一。单细胞蛋白（single cell protein,SCP）在解决世界粮食与蛋白饲料短缺问题存在较大潜质。经多年研究,单细胞蛋白在菌种选育、生产工艺、发酵原料等方面均取得了较大进展,但单细胞蛋白饲料成本仍居高不下,在饲料工业中一直未得到大量应用。提高生产单细胞蛋白生产菌株非蛋白氮（non-protein nitrogen,简称NPN）利用效率和生长速度,是降低单细胞蛋白生产成本的关键。本试验从多株酵母菌中筛选出NPN利用能力较强的菌株,并对其进行紫外照射诱变,以期获得菌体蛋白产量高的突变菌株。通过对14株酵母菌对不同碳、氮源利用的研究,确定其最适碳、氮源,并依据14株酵母的生长潜力、菌体蛋白产量、NPN利用能力等进行排名,筛选出综合性能较优的酿酒酵母菌M（Saccharomyces cerevisiae strain YI59）和N2（Saccharomyces cerevisiae isolate AA2）。将酵母菌M和N2作为出发菌,进行紫外照射诱变。以葡萄糖、硫酸铵为碳、氮源,依平板菌落大小与液体发酵菌体蛋白产量进行初筛和复筛,最终获得菌落较大的3株突变菌MU23、MU3和MU5。经液体发酵复筛发现,MU3和MU5菌体蛋白含量较原出发菌M有显著提高,分别提高12.93%和11.82%（P<0.05）,但菌体蛋白产量与出发菌相比无显著差异（P>0.05）;菌株MU23菌体蛋白含量与出发菌M无显著差异（P>0.05）,但菌体蛋白产量较原出发菌M有较大幅度提升,为0.26 g/L,提高13.04%（P>0.05）。综合上述试验结果,使用紫外照射诱变可以达到提高酵母菌NPN利用能力和菌体蛋白产量的目的。     

Intracerebroventricular Infusion of Leptin into Mature Merino Rams of Different Metabolic Status: Effects on Blood Concentrations of Glucose and Reproductive and Metabolic Hormones

In mature Merino rams, nutrition is one of the external cues that most strongly affects the reproductive centres of the preoptic-hypothalamic continuum. The signalling pathways that link dietary status and the activity of the neurones that produce gonadotrophin-releasing hormone signals are thought to be partly hormonal in nature to reflect the amount of body reserves. Among the hormones thought to be involved are insulin and leptin. This study tested whether recombinant bovine leptin infused (0.4 microg/h) into the third cerebral ventricle would stimulate pulsatile luteinizing hormone (LH) secretion in mature Merino rams when their energy status was low or decreasing, during both chronic (fasting) and acute reductions of energy balance. Leptin may interact with other hormones that depend on energy availability, so we also monitored changes in circulating concentrations of insulin, thyroid hormones, growth hormone, prolactin and adrenocorticotrophin. Overall, our data do not support this hypothesis. The dietary regimes induced clear responses in the metabolic profiles of the animals but there was no clear effect of central leptin administration on LH pulse frequency. The relationships between the hormonal systems measured in the present study add weight to the contention that leptin plays only a permissive role in the nutritional control of the reproductive axis and that other hormonal signals (particularly insulin) or pathways are acting in concert with leptin to stimulate the reproductive axis.     

波尔山羊FSHR5’端序列的SNP多态性及超排效果分析

为探索波尔山羊超排个体排卵数差异与个体遗传特性的相关性,对波尔山羊的FSHR基因(950 bp),分成四段分别设计引物进行PCR-SSCP多态性分析,结果发现一个SNP位点,导致5-’1出现两种基因型。序列分析显示该突变位点位于转录起始点上游-739bp处,属于远端转录启动调控区。统计分析表明AA型个体的平均排卵数与AB型个体的平均排卵数差异极显著(P<0.01),平均胚胎可利用率差异显著(P<0.05),这说明个体的超排潜力可能与其本身的FSHR基因的遗传特性有关。     

放牧强度对混播草地群落数量特征的影响(简报)

放牧强度对人工草地群落数量特征的影响,国内外学者已有报道^[1~2],而有关青藏高原的研究则很少^[3]。Reategui^[4]认为,载畜量增大将使丛生禾草向矮生禾草演替,而导致草地退化。另外,放牧强度对植物群落组成和生物多样性也有很大影响,随着放牧强度的增加,一些适口性高、再生性强、不耐牧的种类减少,而适口性差、耐牧的种类增多^[5]。本试验研究放牧强度对垂穗披碱草(Elymus nutans)/星星草(Puccinellia tenuflora)混播草地群落数量特征的影响,旨在为人工草地的放牧利用提供科学依据。     

凋亡素基因真核表达载体的构建及在人肿瘤细胞中的表达

为探讨凋亡素对肿瘤的基因治疗效果,构建了凋亡素基因的真核表达载体。将凋亡素基因重组入 ｐｃ Ｄ Ｎ Ａ３ 载体,并通过脂质体介导凋亡素在人喉癌、人肺癌细胞系中表达;通过 Ｒ Ｔ Ｐ Ｃ Ｒ 在转染细胞中检测到了凋亡素的 ｍ Ｒ Ｎ Ａ,这为应用凋亡素进行肿瘤的基因治疗奠定了基础。     

A Prospective Study Of Intravenous Catheter Contamination

A one year prospective study was conducted to determine the association between intravenous catheter contamination and increased dwell time, and to identify any related risk factors. Intravenous catheters obtained from 23 cats and 98 dogs in the Intensive Care Unit at the Ontario Veterinary College with dwell times > 72 hours for the test group (n=58) and < 72 hours for a corresponding control group (n=63) were cultured between April 1991 and March 1992. One hundred and twenty one catheters were cultured, 16 jugular, 99 cephalic, and 6 saphenous. The overall contamination rate was 13 out of 121 catheters cultured (10.7%); 9/63 (14.3%) control and 4/58 (6.9%) test catheters. The bacteria isolated were E.aerogenes, S.aureus (3), P.aeruginosa, P.multocida, and Bacillus sp (7). The Bacillus sp positive catheters (5 control and 2 test) were placed during a five day period, and contaminated gauze squares were identified as the source of infection in these catheters. After these were removed from the study, the group infection rate was 6.9% control and 3.6% test. There was no significant difference between groups and no associated risk factors were identified. We conclude that intravenous dwell time need not be restricted to <72 hours.