中华羊茅的优良特性以及利用内生真菌进行育种潜力浅析

中华羊茅(Festuca sinensis)是分布于我国高寒地区的常见野生牧草,抗寒耐旱,耐盐碱,适应性强,品质良好,具有良好的饲用价值,对高寒牧区草地建设、退耕还草、生态治理和畜牧业生产的发展具有十分显著的经济价值。为更深入利用中华羊茅这一种质资源,加快对野生中华羊茅驯化选育的步伐,本文从中华羊茅的植物特性和生物学特性及利用价值3个方面综述并分析了中华羊茅与内生真菌的关系,为利用内生真菌进行中华羊茅育种提供参考。     

水貂育种核心群选育研究

在水貂育种核心群选育中,组建核心群,经过初选、复选、精选、同质选配等措施,培育出体型较大,繁殖力高,生长发育快,毛绒品质好,遗传性能稳定的左家黑色标准水貂优良品种。结果表明:三个世代的选育,母貂的胎产仔数达到了5.58±1.72只,成活数5.33±1.81只;公貂的受配率为91.3%。公貂体重为(2.29±0.18)kg,母貂体重为(1.28±0.14)kg;公貂体长为(44.6±2.17)cm,母貂体长为(38.21±1.32)cm。毛绒品质也得到了提高。结论:水貂体重,体长,繁殖性能,毛绒品质均有所提高,基本达到预期目标。     

平淡中见奇巧,简洁中蕴繁复--论卞之琳诗歌的言语形式

卞之琳诗歌的言语形式不仅是独特的,而且是重要的,甚至可看作卞诗的内核.它使卞诗跨越了许多语言的障碍,获得了自由灵动的表达空间,从某种角度上说,也成就了卞诗的智性与理趣.卞之琳的言语操作技巧细腻多变,如充分调动文言词汇的文化积淀,使语词获得双重影像性;巧妙变通主语,使主语具备极强的诗化功能;通过对句子间逻辑关系的解构与破格,制造"言语道断"等等.     

Analysis of genetic diversity and conservation priorities for six north Ethiopian cattle breeds

Genetic diversity and conservation potential of six indigenous cattle breeds of north Ethiopia was analysed based on 20 microsatellite markers using core set methods. Expected future diversity (assuming assigned extinction probabilities are valid for the next 20-50 years) were 0.988+/-0.011 and 0.980+/-0.010 with expected loss of diversity estimated at 0.02% and 0.74% of current level for the Maximum Variance Total (MVT) and Maximum Variance Offspring (MVO) core sets, respectively. Even though all breeds have contributed to current diversity levels, the Afar and Abergelle breeds only contributed 51% and 62% to the MVT and MVO core sets, respectively, while the Raya breed contributed only 6% and 1.5% to the MVT and MVO core set diversities, respectively. Moreover, prioritizing the six north Ethiopian cattle breeds using the conservation potential obtained from the MVT core set method seems reasonable considering the origin and migration histories of the breeds. Our results suggest that the total current genetic diversity of these breeds can be sufficiently maintained by designing a conservation strategy based on conservation potential of each breed from the MVT core set so that priority is given to lowering the extinction probabilities of breeds with high conservation potential to zero.     

特异乳酸菌对麻羽肉鸡部分消化道生理指标的影响

试验选用温氏麻鸡1日龄母雏3200羽,随机分成4组,每组5个重复,每个重复160只鸡。试验Ⅰ组采用基础日粮(不含有抗生素和乳酸菌);试验Ⅱ组为基础日粮 0.0125%黄霉素;试验Ⅲ组采用基础日粮 1.5%乳酸菌制剂饮水;试验Ⅳ组为基础日粮 1.5%乳酸菌制剂拌料后发酵6h。试验期为72d,分为3阶段:前期(1～4周)、中期(5～8周)、后期(9～11周)。结果表明:发酵组可明显改善盲肠微生物菌群结构和氨浓度、降低盲肠pH值、提高十二指肠和空肠淀粉酶活性(P<0.05)。在添加方式上,饮水组效果不如发酵组。从三个生长阶段看,添加乳酸菌对麻羽肉鸡早期作用好于中后期。     

鹅呼肠孤病毒GRV1株分离鉴定及其σC基因特征性分析

从患运动障碍的雏鹅肝脏和脾脏分离到一株鹅源呼肠孤病毒,该病毒经琼脂扩试验可与番鸭呼肠孤病毒(MuscovyDuckReovirus,MDRV)的抗血清发生交叉反应,推测其为呼肠孤病毒,命名为GRV1。参考GenBank禽呼肠孤病毒(AvianReovirus,ARV)和番鸭呼肠孤病毒小外壳蛋白(minorcoreprotein)σC蛋白基因序列设计合成了一对引物,病毒RNA经RT-PCR扩增,产物为810bp,与预期的目的片断大小一致,测序结果表明σC基因在280～1089区间是一个开放性阅读框架,编码269个氨基酸的蛋白,GC含量为49.88%,等电点为6.497,分子量为29.4Ku。核苷酸序列经DNAStar(6.0)软件分析,与法国番鸭呼肠孤病毒89026株核苷酸同源率为93.0%,与鸡呼肠孤病毒σC基因同源率仅为21%～25%,同源性分析表明鹅呼肠孤病毒与番鸭呼肠孤病毒可能来自同一祖先,建议将鹅呼肠孤病毒连同番鸭呼肠孤病毒归属为正呼肠孤病毒属第二个亚群中不同于禽和内尔森贝海湾呼肠病毒的独立基因群。由蛋白质分析软件Anthepro5.0和MultiCoil软件分析表明,抗原区多位于N末端,没有跨膜区,σC为三股螺旋结构,这是我国第一次在鹅体内分离到呼肠孤病毒,同时也是第一次在数据库中提供σC的序列。     

鸡痘病毒基因探针检测方法的建立及初步应用

利用PCR方法成功克隆了鸡痘病毒（Fowl poxvirus，FPV）4b核心蛋白基因549bp片段，序列分析表明，该序列与模板DNA（AF198100）碱基序列的同源性为99．45％，只有3个碱基差异，第215位由C→T，第386位由T→A，第388位由G→A。回收FPV4b核心蛋白基因549bp片段，以其为模板制备了地高辛标记的DNA探针。对新标记的探针进行标记效率检测，结果显示其标记效率为100mg／L；敏感性检测表明，该探针对同源DNA的检出限量为10Pg；特异性检测结果表明，用本试验所标记的探针对提取的FPV282E4和FPV儿株DNA、重组质粒pMD 18-T-4b进行检测结果均呈阳性，而鸡马立克氏病病毒、鸡传染性喉气管炎病毒、CEF的核酸提取物均成阴性，说明该探针具有较强的特异性。初步应用表明，本试验所建立的FPV的基因探针检测法可用于FPV的检测。     

Linear model vs. survival analysis for genetic evaluation of sires for longevity in Chianina beef cattle

The objective of this study was to compare sire EBVs for longevity in Chianina beef cattle estimated with linear models and survival analysis. Two datasets were created, one considered all data (SURVall), the other only uncensored records (SURVun). The linear models were used to analyze longevity measured as three correlated dichotomous (yes/no) measures of survival in the first three parities (LIN-S3) and as an overall measure of lifespan in months (LIN-LPL). Correlation between sire EBVs from the two survival analyses were 0.85. For LIN-S3 the correlations of EBVs across parities were between 0.69 to 0.93. Medium correlations (from 0.50 to 0.62) were found when only uncensored data (SURVun) were compared to the linear model (LIN-S3). Higher correlations (from 0.71 to 0.93) were found when EBV based on both censored and uncensored data (SURVall) were compared to LIN-S3. Heritability was estimated at 0.11, 0.09 and 0.08 for SURVall, SURVun and LIN-LPL, respectively; and 0.05, 0.02 and 0.02, respectively, for survival in the first three parities according to LIN-S3. Linear and non-linear models differed in many aspects; the most precise EBV were obtained when all data was used in the evaluation.     

Floppy kid syndrome caused by D-lactic acidosis in goat kids

BACKGROUND: Goat kids with floppy kid syndrome have metabolic acidosis, muscle weakness, and depression but no dehydration. HYPOTHESIS: D-Lactate is the major component of acidemia in goat kids with floppy kid syndrome. ANIMALS: Fifty-five goat kids with floppy kid syndrome (group F) and 35 clinically healthy goat kids (group C). METHODS: Clinical, biochemical, microbiologic, virologic, parasitologic, and pathologic examinations. RESULTS: The animals in group F had a blood pH of 7.13 +/- 0.11 and a base excess of -17.8 +/- 3.8 mM, which were both lower than the values in the control animals (pH, 7.32 +/- 0.31; base excess, -0.1 +/- 2.7 mM; P < .001). Floppy kids had a significantly larger anion gap than healthy kids (31.2 +/- 3.7 versus 21.5 +/- 8.5 mM; P < .001). The concentration of L-lactate was lower in floppy kids than in healthy kids (0.67 +/- 0.49 versus 1.60 +/- 1.02 mM), but the concentration of D-lactate was higher in floppy kids (7.43 +/- 2.71 versus 0.26 +/- 0.24 mM; P < .001). Intravenous and oral administration of sodium bicarbonate in floppy kids resulted in a significant increase in blood pH and base excess and a decrease in the anion gap (P < .001). In addition, the concentration of L-lactate increased (P = .039). CONCLUSIONS AND CLINICAL IMPORTANCE: Metabolic acidosis in goat kids with floppy kid syndrome is caused by an increase in the plasma concentration of D-lactate.     

Screening,identifying and sequencing of human single-chain variable fragment specific to hepatitis B virus core protein

AIM:To Screen and identify human single-chain variable fragment (ScFv) specific to hepatitis B virus core protein and determine its gene sequence.METHODS:The recombinant phages were panned by HBcAg coated in a 96-pore plate and 48 clones were identified specific to HBc after three rounds of panning. The specificity of ScFv from the positive clone was determined by ELISA. Then, the soluble ScFv was expressed in E.coli.HB2151 and secreted in the supernatant. Subsequently, SDS-PAGE and dot blot were performed to identify the ScFv in the supernatant and cell lysate. The gene of ScFv specific to hepatitis B virus core protein was sequenced.RESULTS:The ScFv screened from phage antibodies has a specific combination character with hepatitis B virus core antigen. Soluble ScFv was confirmed to express in E.coli.HB2151 and secrete in the supernatant. The sequence of ScFv gene conformed to that of heavy chain and kappa chain of human immunoglubulin. CONCLUSION:Human ScFv specific to hepatitis B virus core protein has been identified by means of the phage display technology, and its gene sequence has been determined.