蜜蜂畸翅病毒SYBR GreenⅠ荧光定量RT-PCR检测方法的建立

为建立蜜蜂畸翅病毒SYBR GreenⅠ荧光定量RT-PCR检测方法,通过构建蜜蜂畸翅病毒(DWV)RDRP基因部分序列的标准质粒作为模板,进行了标准曲线的建立,并对所建立方法进行了特异性和灵敏度测试。结果表明:所建立的荧光定量RT-PCR扩增效率E=100%,R2=0.999,最低检出量为100个拷贝;该方法仅能检出DWV病毒,而不能检测出蜜蜂黑王台病毒、囊状幼虫病毒,具有很好的特异性。表明已成功建立了特异灵敏的DWV实时荧光定量RT-PCR检测方法。采用所建方法对昆明部分蜂场进行了DWV感染状况调查,结果表明昆明地区东方蜜蜂带毒率为54%,提示DWV病毒在昆明地区东方蜜蜂中存在流行。     

TTC法测定嵩草种子生活力的适宜条件研究

在不同温度（２０℃,２５℃,３０℃,３５℃,４０℃,４５℃）,不同ＴＴＣ浓度（０．１％,０．２％,０．３％,０．４％,０．５％,０．６％）下,在０～１２ｈ内测定了线叶嵩草种子生活力的适宜条件。结果表明：在３５℃的温度、０．１％的ＴＴＣ浓度和３ｈ的染色时间下,可获得最佳染色效果,可作为线叶嵩草种子生活力测定的适宜条件。     

新蚕品种“野三元”原原种试繁初报

通过对强健性多丝量新蚕品种"野三元"原原种野A、野B、784、84Y2的试繁,初步了解和掌握了各品系的特征、发育特性、制种特点,对于进一步搞好原原种、原种、一代杂交种繁育,为蚕种场、蚕农提供优质蚕种奠定了良好基础。     

A REVIEW OF NONCONVENTIONAL ULTRASOUND TECHNIQUES AND CONTRAST-ENHANCED ULTRASONOGRAPHY OF NONCARDIAC CANINE DISORDERS

Modern ultrasound contrast media are gas-containing stabilized microbubbles that remain intact in the circulating blood for several minutes after intravenous injection and increase the intensity of the backscattered ultrasound. When the microbubbles disappear from the blood, they can be detected in the parenchyma of the liver and the spleen for about 30 more minutes (late liver- and spleen-specific phase). The insonated microbubbles produce second harmonic ultrasound frequencies, whose detection requires nonconventional ultrasound modalities such as pulsed inversion imaging. Nonconventional ultrasound techniques can also be used without microbubbles because second harmonics can be generated by ultrasound in tissues as well. The physical principles and advantages of nonconventional ultrasound techniques are described. The circulating microbubbles can be used not only to enhance weak Doppler signals, but also to perform dynamic contrast studies. Contrast-enhanced dynamic ultrasound studies--similar to contrast-enhanced CT and MRI examinations--have been used in humans to characterize lesions noninvasively (i.e., without biopsies) found during conventional ultrasound examinations. To map the distribution of contrast medium in a nodule or in an organ, specific scanning techniques such as stimulated acoustic emission have been developed. Stimulated acoustic emission occurs when high acoustic pressure ultrasonic waves disrupt the stationary or slowly moving microbubbles. This results in the release of a large amount of harmonic ultrasound frequencies. When the stimulated acoustic emission technique is used for dynamic studies, scanning must be interrupted several times to allow the microvasculature of the lesion to refill with microbubbles (interval delay imaging). The contrast patterns of malignant and benign hepatic nodules in humans have been the most intensively studied. Another type of dynamic study in humans measures the transit time of the contrast medium; that is, how fast the peripherally injected microbubbles reach the hepatic veins. Hepatic cirrhosis can be differentiated from other diffuse parenchymal liver diseases by a shorter transit time. Introducing nonconventional ultrasound techniques and ultrasound contrast media in veterinary diagnostic imaging may have potential value; however, intensive research should be carried out before ultrasound contrast agents can routinely be used in clinical practice.     

Effect of delaying the time of insemination with sex-sorted semen on pregnancy rate in Holstein heifers

The objective of the study was to evaluate the interval from onset of oestrus to time of artificial insemination (AI) to obtain the optimum pregnancy rate with sex-sorted semen in Holstein heifers. Heifers in oestrus were detected and inseminated only by using heat–rumination neck collar comprised electronic identification tag at the age of 13–14 months. Heifers (n = 283) were randomly assigned to one of three groups according to the timing of insemination at 12–16 hr (G1, n = 97), at 16.1–20 hr (G2, n = 94) and at 20.1–24 hr (G3, n = 92) after reaching the activity threshold. The mean duration of oestrus was 18.6 ± 0.1 hr, and mean peak activity was found at 7.5 ± 0.1 hr after activity threshold. The mean interval from activity threshold to ovulation was 29.4 ± 0.4 hr. The overall pregnancy per AI (P/AI) was 53.0% at 29–35 days and 50.9% at 60–66 days after AI. There was a significant reduction between G1 (13.8 ± 1.4 hr) and G3 (7.9 ± 1.4 hr) related to the intervals from AI to ovulation time. Sex-sorted semen resulted in significantly higher P/AI at 29–35 days when heifers inseminated in G3 (60.9%) after oestrus than those inseminated in G1 (49.5%) and G2 (48.9%). In terms of fertility, when the temperature–humidity index (THI) was below the threshold value (THI ≤65) at the time of AI, there was a tendency (≤65; 57.2% vs. > 65; 47.1%) for high pregnancy rate. There was no effect of sire on P/AI. In addition, the interaction of the technician with the time of AI was found significant, and three-way interaction of technician, sire and time of AI was tended to be significant on pregnancy rate. Thus, in addition to delaying the time of insemination (between 20.1 and 24 hr) after oestrous detection, THI and experienced technician were also found to be critical factors in increasing fertility with the use of sex-sorted semen in Holstein heifers.     

SD雄鼠3种不同新蛋白构型GnRH去势抗原免疫学及生物学效果对比研究

旨在对比研究SD雄鼠3种不同新蛋白构型GnRH抗原的免疫学及生物学效果。本研究新蛋白构型GnRH抗原设计采用增加GnRH拷贝数和增大抗原分子量方法。以化学合成法合成G6K-GnRH并列体(G6K-GnRH-tandem,G6KT)作为新蛋白GnRH抗原制备的基本单元。将G6KT二聚化,形成抗原Ⅰ(G6KTD),将G6KT和G6KTD分别与卵清蛋白(OVA)偶联,分别形成抗原П(G6KT-OVA)及抗原Ⅲ(G6KTD-OVA)。试验分5组:完整对照组(不做任何处理,intact control)、外科阉割去势组(surgical castrates)及3种新蛋白构型GnRH免疫组(G6KTD、G6KT-OVA及G6KTD-OVA免疫组)。将(G6KTD、G6KT-OVA、G6KTD-OVA)3种不同新蛋白构型GnRH抗原配于Specol佐剂,分别免疫SD雄鼠,6周龄时初免,腿部肌肉注射1 mL乳化抗原(含相应新构型GnRH蛋白100μg),8周后加免,注射剂量与方法同初次免疫,每试验组12只雄鼠。放免法及酶联免疫法测定血清抗体及生殖激素浓度变化,qPCR检测垂体-睾丸生殖相关基因mRNA表达变化。结果显示:1)SD雄鼠主动免疫3种不同新蛋白构型GnRH抗原后均能产生良好的抗体反应。2)G6KT-OVA及G6KTD-OVA免疫组仅初免就能诱发较高水平的抗体产生,并显著降低雄鼠血清LH、FSH、睾酮(T)及抑制素B (INHB)浓度(P<0.05);试验结束时,该两种抗原免疫组雄鼠睾丸重量及体积均降低,精子发生完全被终止,垂体GnRHR、LHβ、FSHβ及睾丸LHR、FSHR、INHα、INβA及INHβB mRNA表达显著下调(P<0.05)。3)G6KTD免疫组12只雄鼠中,9只(75%)在加免后血清LH、FSH、T及INHB浓度显著降低(P<0.05),试验结束时睾丸重量及体积均显著降低(P<0.05),精子发生受到明显抑制(P<0.05)。综上表明:新蛋白构型G6KT-OVA和G6KTD-OVA具有极强的免疫原性,初次免疫就能达到抑制生殖激素分泌的目的,在作为单剂量GnRH疫苗方面具良好的开发前景;同时G6KTD也具有较强的免疫原性,可不与载体蛋白偶联单独作为GnRH去势抗原,继而避开GnRH分子与载体蛋白偶联所面临的GnRH抗原损失严重及与载体蛋白偶联的后续纯化等问题。本研究结果为研发高效GnRH去势疫苗及其大规模应用提供了理论参考。     

草原蝗虫空间格局及其抽样技术的研究

根据改进的m*=α′ β′m γm2模型和聚集度指标,研究了草原混合种群的空间分布.结果表明,蝻期蝗虫呈聚集分布,在聚集的个体群内,个体间是相互排斥的.成虫期分布的基本成分是个体群,个体间相互吸引,而个体群的分布是均匀的.以聚集度(m*/m)的时序动态表明,蝗蝻初期呈均匀分布,盛期呈聚集分布,成虫期为均匀分布.在测报和防治中,混合种群的理论抽样数为20～40个样点.     

优质牦牛肉肉质的综合评价

2000-2002年对大通牛场40头6月龄不同性别的全哺乳牦牛的肉质进行了综合评价。对供试牦牛肌肉pH、嫩度、肌纤维细度、系水率、肉的贮存损失、肉的煮熟时间、熟肉率和烹饪损失率及肉色等进行了评价，分析了肌肉的化学成分，氨基酸及微量元素含量。结果表明该牦牛肉系水率强，肉的煮熟时间短，肉的贮存损失及烹饪损失较小，肌纤维较细，肉色深红。并具有蛋白质含量高，脂肪含量低及富含各种氨基酸的特点。     

Effect of time delay and storage temperature on blood gas and acid-base values of bovine venous blood

The aim of this study was to investigate possible changes in the gas composition and acid-base values of bovine venous blood samples stored at different temperatures (+4, 22 and 37 degrees C) for up to 48 h. Five healthy cattle were used in the study. A total of 15 blood samples collected from the animals were allocated into three groups, which were, respectively, then stored in a refrigerator adjusted to +4 degrees C (Group I, n=5), at a room temperature of about 22 degrees C (Group II, n=5) and in an incubator adjusted to 37 degrees C (Group III; n=5) for up to 48 h. Blood gas and acid-base values were analysed at 0 (baseline), 1, 2, 3, 4, 5, 6, 12, 24, 36 and 48 h of storage. A significant decrease (p<0.001) was found, in the pH of the refrigerated blood after 5 h and its maximum decrease was recorded at 48 h as 0.04 unit. There were also significant alterations (p<0.001) in the blood pH of the samples stored at room temperature and in the incubator after 2 and 3 h, respectively. The maximum mean alteration in pCO(2) value for Group I was -0.72 kPa during the assessment, while for groups II and III, maximum alterations in pCO(2) were detected as +2.68 and +4.16 kPa, respectively. Mean pO(2) values increased significantly (p<0.001) for Group I after 24 h and for Group II after 6 h, while a significant decrease was recorded for Group III after 24 h (p<0.001). Base excess (BE) and bicarbonate (HCO(3)) fractions decreased significantly for all the groups during the study, compared to their baseline values. In conclusion, acid-base values of the samples stored at 22 and +4 degrees C were found to be within normal range and could be used for clinical purposes for up to 12 and 48 h, respectively, although there were small statistically significant alterations.     

应用RT—PCR方法检测鸭病毒性肝炎新型和I型病毒

鸭病毒性肝炎病毒是危害养鸭业的重要病毒性传染病,主要感染低日龄雏鸭,临床上分离到的病原主要为鸭病毒性肝炎I型病毒和鸭病毒性肝炎新型病毒,为了加快本病的检测速度,尽快确诊病原,根据GeneBank上两种毒株的基因组序列,选择两种毒株的差异基因序列分别设计了一对特异性的检测引物,将两对引物放在一个PCR反应体系中,两种毒株分别进行特异性扩增,根据扩增片段的大小进行鉴别,建立了可以同时检测鸭病毒性肝炎病毒I型和新型毒株的复合RT—PCR方法,该检测方法快速,特异性强,灵敏性高,可以用于鸭病毒性肝炎病毒的分型鉴别检测。