原子吸收分光光度法测定人发痕量镉的研究

以硝酸—高氯酸为消化液,消解人发试样,采用碘化钾—甲基异丁酮萃取发样中的镉,采用原子吸收分光光度法,将有机相喷雾测定。并且对直接法、标准加入法和原子吸收分光光度法进行了比较。本测定方法 C? V小于 3.1%,标准加入回收率在 95.6%～103.2%之间,结果可靠,适用于人发中痕量镉的测定。     

调控动物性状相关长链非编码RNA的研究进展

长链非编码RNA(long non-coding RNA,lncRNA)是基因转录过程中产生的一类长度大于200个核苷酸(nt)的非编码RNA(non-coding RNA,ncRNA)。lncRNA的表达水平通常低于mRNA,且无高度保守序列,缺少开放阅读框,但它们具有更强的组织特异性表达模式。lncRNA可以通过与DNA、RNA(mRNA,miRNA,环状RNA)和蛋白质进行相互作用来发挥其功能,因此可作为信号分子、诱导物等来调节复杂的基因表达网络。作为一种新的调节分子,lncRNA正在成为基因表达调控中新的重要参与者,且近年研究表明,其与家畜动物性状调控密切相连。本文对lncRNA在动物肌肉生长分化、脂肪沉积、毛囊发育和繁殖方面进行了综述,旨在为lncRNA在家畜遗传育种上的应用提供依据。     

云南半细毛羊毛囊干细胞表面标记物的鉴定

设计8对引物（CK14、CK15、CK19、CD34、CD271、CD200、nestin和β1）,分别扩增云南半细毛羊成纤维细胞和毛囊干细胞表面标记物.结果表明：在成纤维细胞中CK19和β1表现为阳性,而在毛囊干细胞中CK14、CK19和β1表现为阳性,其他标记物的表达都为阴性.因此,CK14可以作为鉴定云南半细毛羊毛囊干细胞的表面标记物之一.     

Hair cortisol concentration in pre‐ and postpartum dairy cows,and its association with body condition,hock health,and reproductive status

The objective of this study was to investigate the profiles of hair cortisol concentrations as an index of chronic stress in dairy cows in association with their health, nutrition, and reproductive parameters. For 25 Holstein dairy cows, hair was collected from the tail switch ?19.2 ± 11.4, 44.8 ± 11.9, 103.0 ± 9.9, and 168.0 ± 9.7 days postpartum (L0, L1, L2, and L3, respectively). Body condition scores were negatively correlated with hair cortisol concentrations (r = ?0.255), and hock health scores were positively correlated with hair cortisol concentrations (r = 0.236, p < 0.05). Hair cortisol concentrations during the postpartum period showed different patterns according to the time of first artificial insemination (AI) and fertility. Cows that were submitted to first AI by 86 days postpartum showed a peak hair cortisol concentration at L1, whereas cows with delayed first AI had a peak at L2. The hair cortisol concentrations of subfertile (≥168 days) cows were significantly higher at L1 and L2 compared with L0, whereas hair cortisol concentrations of fertile cows (<168 days) were not different among the sampling times. These results indicate that cows with health problems appear to experience greater chronic stress, which may impair their reproductive function.     

褪黑激素对长毛兔产毛性能及兔毛品质的影响

试验旨在研究褪黑激素(Melatonin,MT)对长毛兔夏季产毛的影响。选择1.5岁左右的皖系长毛兔60只,其中公兔40只,母兔20只,随机分为4组,分别皮下埋植0、25、40、55 mg的褪黑激素,经过70 d的养毛期后测定各组产毛量及粗毛和细毛的长度变化差异,分析褪黑激素对长毛兔产毛性能的影响。结果显示:公兔40 mg埋植组产毛量显著高于埋植前产毛量(P<0.05),55 mg埋植组产毛量显著高于对照组产毛量(P<0.05);母兔对照组试验后剪毛量显著低于试验前剪毛量(331.0 g vs 284.8 g,P<0.05),而3个褪黑激素埋植组试验后产毛量下降幅度并不显著(P>0.05)。皮下埋植40 mg或55 mg褪黑激素能够增加皖系长毛兔公兔或母兔的粗毛长度,但对细毛长度和兔毛细度均无显著影响(P>0.05)。说明长毛兔皮下埋植40 mg和55 mg褪黑激素能够提高公兔夏季产毛量且抑制母兔夏季产毛量的降低,同时增加公、母兔粗毛长度。研究结果可为褪黑激素的合理利用提供参考,并为揭示其对促进长毛兔夏季兔毛生长的作用机制奠定基础。     

Phenylbutazone induces equine glandular gastric disease without decreasing prostaglandin E2 concentrations

In equids, phenylbutazone at high doses induces gastric disease, primarily in the glandular portion of the stomach. However, the mechanism of nonsteroidal anti‐inflammatory drug (NSAID)‐induced gastric disease in horses has yet to be determined. While phenylbutazone‐associated ulceration is often attributed to a decrease in basal gastric prostaglandins, this has not been demonstrated in the horse. Twelve horses were randomly assigned to treatment (n  = 6; 4.4 mg/kg phenylbutazone PO in 20 ml molasses q 12 hr for 7 days) or placebo (n  = 6; 20 ml molasses PO q 12 hr for 7 days) groups. Before treatment and 3 and 7 days after initiation of treatment, gastroscopy was performed and glandular gastric biopsies were collected and frozen at ?80°C. Glandular disease was assessed on a scale of 0–4. Prostaglandin E₂ concentrations in biopsies were measured using a commercially available enzyme‐linked immunosorbent assay. All phenylbutazone‐treated horses developed grade ≥2 glandular disease. Prostaglandin concentrations increased over time (p  = .0017), but there was no effect of treatment (p  = .49). These findings indicate that despite induction of glandular disease grade ≥2, phenylbutazone did not decrease basal glandular gastric prostaglandin E₂ concentration.     

细毛羊皮肤毛囊miR-1298-5p的靶基因预测及验证

为探讨miR-1298-5p及其靶基因与细毛羊毛囊生长发育的关系,本实验以乾华肉用美利奴羊不同发育时期皮肤毛囊组织为材料,通过生物信息学方法预测miR-1298-5p的靶基因,采用RT-PCR和Western Blot对miR-1298-5p及其靶基因进行定量检测;扩增靶基因3'UTR区,构建野生型和突变型靶基因表达载体后与miR-1298-5p mimics共同转染到HEK293T/17细胞中,利用双荧光素酶报告基因实验验证miR-1298-5p与靶基因的靶向关系。结果表明:FGF_2基因3'UTR区含有miR-1298-5p结合位点,FGF_2为miR-1298-5p潜在靶基因,通过核酸水平和蛋白水平定量表达规律发现miR-1298-5p与靶基因FGF_2呈负相关,初步确定FGF_2为miR-1298-5p的靶基因。双荧光素酶报告基因实验显示,miR-1298-5p mimics能够抑制野生型FGF_2的靶位点报告载体的荧光素酶活性;但当靶基因结合位点突变后,FGF_2被抑制的荧光素酶活性能够得到恢复。综上,miR-1298-5p与FGF_2有靶向关系,miR-1298-5p能通过负调控FGF_2的表达调控羊毛囊发育。     

环境胁迫及相关植物激素在水稻根毛发育过程中的作用

根毛作为根系吸收水分和养分的重要结构,其生长发育同时受到外界环境与遗传因子的调控,也在植物应对逆境胁迫时发挥着重要的作用。本文对元素缺乏等环境胁迫、遗传因子及脱落酸、乙烯和生长素为核心的激素调控网络在水稻根毛发育中的作用及相互关系进行了总结,并就目前该研究领域内尚未解决的问题及相关研究提出了展望。     

高效降解猪毛角蛋白菌群构建及其降解效果研究

为丰富猪毛角蛋白降解菌微生物资源库及开发猪毛角蛋白高效降解产品，采用富集、驯化培养的方法，以猪毛为唯一碳氮源从土壤中筛选猪毛角蛋白高效降解菌株，通过不同菌株组合培养的方法，构建了组合菌群。结果表明，经驯化筛选，共获得3株对猪毛降解效果较好的菌株，与对照相比，其猪毛降解率（10 d）为58.0%~65.3%，且3株菌株对鸡毛、鹅毛和羊毛也表现出良好的降解效果，是一类广谱角蛋白降解菌。3株高效猪毛降解菌株（菌株编号为E-2-2、E-1-4和E-3-2）分别鉴定为地衣芽孢杆菌（Bacillus licheniformis）、蕈状芽孢杆菌（Bacillus mycoides）和链霉菌（Streptomyces koyangensis）。通过单一菌株及不同组合菌群降解效果的对比分析，成功获得最优菌群组合，其猪毛降解率（10 d）高达81.8%，比单一菌株的猪毛降解率（10 d）最多提高了23.8个百分点。在降解过程中产生了大量可溶性蛋白质，二硫键中的硫也随之转化为以硫酸盐为主要形式的含硫化合物。研究表明，通过不同菌株间协同增效可大幅提高猪毛降解效果，在氨基酸饲料生产中具有潜在的应用价值。