5龄蚕立体条桑育研究

研究了5龄立体饲育架制作，条桑收获及饲养技术，明确了全年采用立体条桑育对蚕茧产质量及桑树秋末生长的关系，条桑收获及饲育是一项省工高效的养蚕技术。     

2015―2020年国家西北内陆棉区棉花品种区域试验参试品种(系)枯黄萎病抗性评述

对2015-2020年参加西北内陆棉区区域试验的192个棉花品种(系)枯萎病、黄萎病的抗性分析,为棉花抗病育种及品种推广提供依据.结果表明,参试棉花品种(系)未出现对枯萎病和黄萎病免疫的品种;参试棉花品种(系)对枯萎病的抗性水平较高,除2018年高抗和抗病品种(系)占比为88.2％外,其他年份均在92％以上;参试的品种...     

Comparison of Physicochemical and Structural Properties of Acid-Soluble and Pepsin-Soluble Collagens from Blacktip Reef Shark Skin

Fish collagen has been widely used in tissue engineering (TE) applications as an implant, which is generally transplanted into target tissue with stem cells for better regeneration ability. In this case, the success rate of this research depends on the fundamental components of fish collagen such as amino acid composition, structural and rheological properties. Therefore, researchers have been trying to find an innovative raw material from marine origins for tissue engineering applications. Based on this concept, collagens such as acid-soluble (ASC) and pepsin-soluble (PSC) were extracted from a new type of cartilaginous fish, the blacktip reef shark, for the first time, and were further investigated for physicochemical, protein pattern, microstructural and peptide mapping. The study results confirmed that the extracted collagens resemble the protein pattern of type-I collagen comprising the α₁, α₂, β and γ chains. The hydrophobic amino acids were dominant in both collagens with glycine and hydroxyproline as major amino acids. From the FTIR spectra, α helix (27.72 and 26.32%), β-sheet (22.24 and 23.35%), β-turn (21.34 and 22.08%), triple helix (14.11 and 14.13%) and random coil (14.59 and 14.12%) structures of ASC and PSC were confirmed, respectively. Collagens retained their triple helical and secondary structure well. Both collagens had maximum solubility at 3% NaCl and pH 4, and had absorbance maxima at 234 nm, respectively. The peptide mapping was almost similar for ASC and PSC at pH 2, generating peptides ranging from 15 to 200 kDa, with 23 kDa as a major peptide fragment. The microstructural analysis confirmed the homogenous fibrillar nature of collagens with more interconnected networks. Overall, the preset study concluded that collagen can be extracted more efficiently without disturbing the secondary structure by pepsin treatment. Therefore, the blacktip reef shark skin could serve as a potential source for collagen extraction for the pharmaceutical and biomedical applications.     

菜豆锈菌侵染过程的显微和超微观察

 本文报道了通过微分干涉衬显微镜、荧光显微镜及扫描电镜和透射电镜所观察到的菜豆锈菌的侵入和扩展过程。菜豆锈菌夏孢子萌发多产生1个芽管,偶尔也产生双芽管。芽管以气孔侵入为主,也可从表皮直接侵入。侵入前形成或不形成明显的附着胞。气孔侵入的芽管首先在气孔腔内形成气孔下囊,再进一步分化出圆形的膨大体,由膨大体产生1~2支初生菌丝。初生菌丝与叶肉细胞壁接触后分化出吸器母细胞,吸器母细胞进入叶肉细胞内部形成吸器。初生侵染菌丝在产生吸器母细胞的部位的后部产生分枝,形成次生侵染菌丝在叶肉细胞间蔓延。     

温湿度调控对番茄灰霉病菌产生的细胞壁降解酶的影响

 番茄灰霉病菌在致病过程中能够产生4种细胞壁降解酶,以PMG酶活性最高,其次是β-葡萄糖苷酶和PG酶,Cx最少。灰霉病菌在不同温度下侵染番茄叶片时产生的致病酶活性不同,4种酶在20℃时表现了最高的活性,15℃次之,当温度达到25℃时,各种酶的活性都急剧下降,随着温度的再升高,酶活更低。随着湿度的增高,病菌产生的细胞壁降解酶的活性也增加,当相对湿度达到90%以上时,4种酶的活性也达到最高。温湿度对番茄灰霉病菌产生细胞壁降解酶的影响趋势,与其对发病的影响趋势是一致的。     

一步法实时定量RT-PCR检测小反刍兽疫病毒方法的建立

建立了检测小反刍兽疫病毒的快速、特异的基于Taqman的一步法实时定量RT-PCR方法。通过对GenBank已公布的小反刍兽疫病毒N基因序列进行序列比较分析,设计了一对特异性引物和一条Taqman探针。利用这对引物和探针对来自不同疫源地的小反刍兽疫病毒RNA样本进行检测,都获得了特异性扩增,但是,不与牛瘟病毒、海豚麻疹病毒等其他种的麻疹病毒属病毒发生交叉反应。本方法具有高度灵敏性,最低可检测到810拷贝的RNA模板。在模板浓度为8.1×102到8.1×108拷贝范围内,都呈现良好的线性关系,而且无论是组内和或组间重复的变异系数都很低。     

松辽黑猪胰岛素样生长因子Ⅱ基因PCR-SSCP多态性分析

采用PCR-SSCP技术检测胰岛素样生长因子Ⅱ(IGF-Ⅱ)基因外显子3和外显子4在松辽黑猪中的单核苷酸多态性,同时研究该基因对松辽黑猪部分重要生长、胴体性状的影响。结果表明:3对引物中,只有p3的扩增片段存在多态性。p3的扩增片段在松辽黑猪中检测到AA、AB和BB 3种基因型;测序分析发现BB型与AA型相比在IGF-Ⅱ基因(AY044828)第21585 bp处有G→C突变,松辽黑猪AA、AB和BB基因型频率分别为0.6956、0.2609和0.0435。AA基因型对瘦肉率(P<0.05)、日增重(P<0.05),BB基因型对平均背膘厚(P<0.01)有正遗传效应,对其他性状差异不明显。     

乳牛体型性状线性评定数学模型的指导和应用

本文说明了乳牛体型性状线性评定的常规方法,在此基础上推导出了该评定方法的数学模型。该模型的提出,极大地简化了常规评定方法的繁琐计算,值得在乳牛业生产实践中推广使用。     

应用滤波方法提高高山松地上生物量遥感估测精度的研究

基于1987年、1992年、1997年、2002年、2007年、2012年分布在香格里拉市的34个高山松固定样地数据,以及Landsat时间序列数据集,利用谷歌地球引擎和Python,通过3种滤波算法对时间序列数据进行重构,应用随机森林算法对森林地上生物量进行估测,根据模型评价指标对重构前后时间序列数据的估测效果进行分析。结果表明：采用3种不同滤波方法重构的时间序列数据训练的非参数模型,其拟合精度和预测精度均高于滤波前时间序列的预测精度,整体均方根误差和相对均方根误差指标均优于滤波前数据,其中ARMIA方法最佳。应用滤波方法在一定程度消除了影像自身所携带的大量噪声和不确定性,有效地提高了数据质量,提高了高山松地上生物量遥感估测的精度。     

Green tea polyphenols supplementation alters immunometabolism and oxidative stress in dairy cows with hyperketonemia

Peripartal cows often experience negative energy balance, and are therefore prone to suffering from metabolic diseases such as hyperketonemia, which causes financial losses in dairy farms. This study aimed to investigate the effect of green tea polyphenol (GTP) supplementation during the periparturient period on production performance, oxidative stress and immunometabolism in dairy cows with hyperketonemia. One hundred Holstein cows were assigned to GTP (0.2 g/kg DM; n = 50) or control (without GTP; n = 50) group based on body weight, previous milk yield, and parity on d 15 before expected parturition. Subsequently, 10 cows with hyperketonemia were selected from each group, according to blood β-hydroxybutyric acid (BHBA) concentration between 1.2 and 2.9 mmol/L from 2 to 3 d postpartum. All cows were fed a close-up diet and a lactation diet with or without GTP supply from 15 d prepartum until 30 d postpartum. Milk and blood samples were obtained from 20 cows selected with hyperketonemia on 10, 20, and 30 d postpartum. Compared with control cows, greater milk yield and lower somatic cell count were observed in GTP cows. The GTP group had lower concentrations of BHBA, free fatty acids, cholesterol, triglyceride, reactive oxygen species, malondialdehyde, and hydrogen peroxide, greater concentrations of glucose, lower activities of aspartate aminotransferase, alanine aminotransferase, and glutamyl transpeptidase, alongside greater activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity. Additionally, GTP supplementation up-regulated concentrations of interleukin-6 and interleukin-10, but down-regulated concentrations of tumor necrosis factor-α, interleukin-1β, interleukin-2, interleukin-8, and interferon-γ in plasma. Greater concentrations of plasma immunoglobulin G were also detected in the GTP group. Overall, the data suggested that GTP supplementation from 15 d prepartum to 30 d postpartum improved the milk yield and health status in cows with hyperketonemia during early lactation.