填饲对朗德鹅SCD5、SREBP2和ELOVL6甲基化和mRNA表达的影响

DNA甲基化是表观遗传学的研究热点之一.为了探索填饲是否能够引起朗德鹅Anser anser)肝脏脂类代谢中DNA甲基化水平以及基因表达量的变化和DNA甲基化修饰作用和基因表达之间的关系.本研究运用焦磷酸测序技术分析鹅肝脏硬脂酞辅酶A去饱和酶5基因(stearovl-CoA desaturase 5,SCD5)、固醇调节元件结合蛋白2基因(sterol regulatory element-binding protein 2,SREBP2)和超长链脂肪酸延伸酶6基因(elongase of very long chain fatty acids 6,ELOVL6)的甲基化水平,再运用qRT-PCR技术进行定量验证.结果显示,SCD5、SREBP2和ELOVL6各2个片段的甲基化水平均在20％以上,均属于高甲基化状态;对照组3个基因各2个片段的甲基化水平均高于填饲组,填饲组与对照组的SCD5-1S和SREBP2-1S片段甲基化差异显著(P＜0.05),SREBP2-2S片段甲基化差异极显著(P＜0.01),SCD5-2S、ELOVL6-1S和ELOLV6-2S片段甲基化差异不显著(P＞0.05);填饲组SCD5和ELOVL6的mRNA表达量均高于对照组,而SREBP2在填饲组的mRNA表达量显著低于对照组(P＜0.05).综合各项指标,填饲引起鹅肝脏组织SCD5、SREBP2和ELOVL6甲基化水平降低,SCD5和ELOVL6 mRNA表达量上升,SREBP2的mRNA表达量降低,表明SCD5和ELOVL6的甲基化修饰对mRNA的表达起反向调控的作用.本实验结果为表观遗传学上DNA甲基化研究方法提供参考,为选育鹅肥肝高产高质系提供重要的分子遗传学依据,也为人类肥胖症和脂肪肝等代谢疾病的研究提供理论依据.     

小菜蛾Btk抗性品系对四种Bt杀虫晶体蛋白抗性发展的研究

使用苏云金芽胞杆菌库斯塔克亚种（Btk）可湿性粉剂对小菜蛾进行继代汰选获得F80代和F100代抗性品系。通过分别测定Cry1Ab、Cry1Ac、Cry1Ah和Cry1Ca四种杀虫晶体蛋白对小菜蛾Btk抗性品系F80代和F100代的室内毒力,明确了小菜蛾Btk抗性品系对四种Bt杀虫晶体蛋白抗性发展规律。研究结果表明,汰选至F80代时,Cry1Ca对小菜蛾的毒力最高,LC50约12.1mg/L,其次为Cry1Ac,LC50约47.7mg/L;而汰选至F100代时,仍以Cry1Ca对小菜蛾的毒力最高,LC50约21.4 mg/L,其次为Cry1Ab,LC50约72.2 mg/L。与相对敏感品系相比,小菜蛾抗性品系对Cry1Ac的抗性发展较快（抗性倍数高达67.3～106.8倍）,对Cry1Ab的次之（抗性倍数高达60.0～66.1倍）,而对Cry1Ca和Cry1Ah的抗性发展较慢（抗性倍数分别为3.4～6.0倍和1.6～2.5倍）。以上结果说明,在主效杀虫基因为Cry1Ac的Btk药剂选择压力下,小菜蛾对四种Bt杀虫晶体蛋白的抗性发展速度差异较大,且Cry1Ac和Cry1Ab存在交互抗性风险...     

灌喂必需氨基酸模式溶液对草鱼全鱼_省略_肌肉_肝胰脏蛋白质合成代谢的影响

采用大剂量食道灌喂DL－[4-^3H]-Phe，研究不同EAA模式下，20－30g体重草鱼种的全鱼和肌肉，肝胰脏的蛋白质合成代谢，结果表明：（1）分别缺乏Lys,Met,Trp Arg的4种极端不平衡EAA模式，同草鱼肌肉EAA模式即相对平衡的基础模式相比，肌肉，肝胰脏及全鱼的蛋白质合成速率（FSR）均显著降低，其降低程度高低依次为Met,Lys,Arg,Trp;(2)肝胰脏，肌肉人的蛋白质合成代谢与整体蛋白质合成代谢对EAA模式的改变产生相同的变化趋势，并且三者蛋白质合成代谢速率为肝胰脏＞全鱼＞肌肉；（3）EAA模式的Lys,Met,Trp,Arg4因素中，对肌肉，肝胰脏蛋白质合成速率影响最大的是Met,其余依次为Lys,Arg,Trp。     

3种蛋白水平饲料对克氏螯虾生长和虾肉品质的影响

采用40%、33%、27%3种蛋白水平的配合饲料和纯菜粕(对照组)分别投喂克氏螯虾(Procambarus clar-kii)98 d,研究不同蛋白水平的饲料对克氏螯虾生长和肉质的影响。结果显示:克氏螯虾增重以27%组最高,其次是40%组、33%组,对照组最低;克氏螯虾体长增长以27%蛋白组最高,其次是33%、40%组,对照组最低;饲料系数以33%组最低,其次是27%组、40%组,对照组最高。随着饲料蛋白质含量升高,蛋白质效率呈下降的趋势。27%组出肉率、虾黄率含量最高;滴水损失40%组显著高于27%组(P<0.05);蒸煮损失27%组(P<0.01)、33%组(P<0.05)组均显著低于对照组;不同蛋白水平组间的虾肉水分含量、肉样pH值(pH1和pH2)、熟肉率、嫩度没有显著差异。试验表明克氏螯虾饲料中蛋白质水平以27%和33%比较适合。     

镉胁迫下2种杨树可溶性蛋白含量的变化研究

对速生杨107和速生杨118进行不同浓度镉处理,研究其对叶和根的可溶性蛋白含量的影响。结果表明,2种杨树叶片中可溶性蛋白含量随着镉浓度的增加而增加。处理20 d,镉处理组叶片中的可溶性蛋白含量明显增加(除了杨树118的50μmoL/L镉处理组)。在高浓度镉(500μmoL/L)条件下处理30 d,其含量急剧下降。在50μmoL/L镉处理条件下,2种杨树根的可溶性蛋白含量呈现持续上升的趋势。在100μmoL/L镉处理组中,速生杨107根的可溶性蛋白含量在前30 d呈上升趋势,速生杨118根的可溶性蛋白含量在整个处理期中一直较高。高浓度镉(500μmoL/L)处理20 d后2种杨树根部可溶性蛋白含量均急剧下降。     

鸡堆型艾美尔球虫3-1E抗原表位的生物信息学预测

应用生物信息学分析和预测鸡堆型艾美尔球虫3-1E蛋白二级结构和抗原表位,为确定和筛选优势表位,研制安全、高效表位疫苗奠定基础。以克隆获得的鸡堆型艾美尔球虫3-1E蛋白氨基酸一级结构为基础,采用DNAStar软件和生物信息学在线分析程序Prot Param、SOSUI、IEDB、SYFPEITHI等预测3-1E蛋白理化性质和二级结构,并分析其序列跨膜区、可溶性、亲水性、可及性、柔韧性参数以及抗原指数,预测B细胞表位和T细胞表位的可能区域。3-1E蛋白由170个氨基酸组成,分子式C818H1257N213O272S3,分子质量18.5234 ku,理论等电点为4.25,半衰期为10 h;无跨膜区均为膜外区,是一种可溶性蛋白。其二级结构中α螺旋占31.76%,β转角为12.35%。B细胞表位预测区域:44-49、65-67、86-87、111-116;分值较高的T细胞表位区域:52-60、94-102、97-105、154-162、157-165。运用生物信息学方法确定3-1E存在多个抗原表位,对进一步研究3-1E的抗原性和研发优势表位疫苗具有重要意义。     

信阳茶区不同嫩度茶鲜叶灰分 蛋白质含量与品质的关系

茶叶中含有的灰分和大量蛋白质对茶叶的品质具有重要作用。灰分除了在制茶过程中会有少量掺入外,大部分都来自鲜叶中,且鲜叶经过加工其含量不发生显著变化。大量的蛋白质也来自鲜叶。鲜叶是制茶的原料,其老嫩程度决定着茶叶质量的优劣。本实验分析了不同嫩度鲜叶中总灰分、水溶性灰分、粗蛋白的含量差异,目的在于为新梢采摘,提高信阳毛尖茶的品质,提高茶叶安全卫生质量提供参考依据。     

Expression of Wnt1 and LGR5 in gastric mucosa with stress ulcer after TBI in rats

AIM To investigate the expression of Wnt1 and LGR5 in gastric mucosa with stress ulcer after traumatic brain injury （TBI） in rats, and to study the relationship between Wnt1/LGR5 expression and stress ulcer after TBI. METHODS Healthy 7-week-old male SD rats （n=30） were randomly divided into 3 groups： sham operation （sham） group, mild TBI （mTBI） group, and severe TBI （sTBI） group. The mTBI and sTBI were induced by electronic cortical contusion impactor. Neurological severity score （NSS） was calculated 24 and 48 h after modeling. Mucosal blood flow in gastric fundus, greater curvature, pylorus and cardia of anesthetized rats 48 h after injury was measured by Doppler flowmeter. All rats were sacrificed, and their gastric tissues were harvested after 48 h and then stained with hematoxylin and eosin. The protein expression of Wnt1 and LGR5 was analyzed by Western blot and immunohistochemistry. RESULTS Compared with sham group, the NSS in mTBI group and sTBI group was significantly increased （P<0.01）. Compared with sham group, the gastric mucosal blood flow of the rats after TBI was significantly decreased （P<0.01）, and the decrease in sTBI group was more significant than that in mTBI group （P<0.05）. The protein expression of Wnt1 and LGR5 in mTBI group was significantly higher than that in sham group （P<0.05）, and that in sTBI group was significantly higher than that in mTBI group （P<0.05）. Normal glandular gastric tissue was observed, and no abnormal change was found in sham group, while the infiltration of inflammatory cells in gastric lamina propria, mucosa and submucosa was obvious in mTBI group and sTBI group. CONCLUSION Traumatic brain injury activates Wnt1 and LGR5 expression to induce inflammatory changes in gastric mucosa, and then induces stress ulcer. This results provides experimental basis for the pathogenesis and treatment of stress ulcer after trauma.     

Corticosterone inhibits LPS-induced expression of NLRP3 in mouse macrophages and its relation with XO

AIM: To investigate the inhibitory effect of corticosterone (CORT) on lipopolysaccharide (LPS)-induced expression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) and its relation with xanthine oxidase (XO). METHODS: An inflammatory model of mouse macrophage RAW 264.7 was established by stimulating with LPS. Total cellular protein was extracted after the macrophages were treated with CORT at different concentrations (0~900 μg/L). The protein levels of NLRP3 and caspase-1 were determined by Western blot. According to the treatments, the macrophages were divided into control group, LPS group, LPS+CORT group and LPS+allopurinol group. Cell components were extracted at 0, 0.5, 1, 1.5 and 2 h. The protein levels of NLRP3 and XO were determined by Western blot,and the mRNA expression of NLRP3 and XO was detected by real-time PCR. RESULTS: CORT at 700 μg/L and above significantly inhibited the expression of NLRP3 and the activation of caspase-1 in the macrophages induced by LPS (P<0.05). Compared with LPS group, the expression of NLRP3 and XO in LPS+CORT group was inhibited (P<0.05), and the expression of NLRP3 in LPS+allopurinol group was also reduced (P<0.05).CONCLUSION: High concentration of CORT inhibits the expression of NLRP3 in LPS-induced mouse macrophages, which is associated with XO. The inhibitory effect of CORT may be related to the reduction of XO expression.     

鲢鱼肉肌原纤维乳糖蛋白的制备及其溶解性

研究了乳糖与鲢鱼肉肌原纤维蛋白(Mf)在不同反应条件下通过美拉德反应制备的肌原纤维乳糖蛋白的功能特性。测定了其在0．1mol／L Nacl溶液中的溶解性，并对其进行了SDS聚丙烯酰胺凝胶电泳分析。乳糖与Mf以1：1、2：1、4：1和6：1的质量比混合，冷冻干燥后，在50和55℃，相对湿度为65％的条件下反应0～48h制备的肌原纤维乳糖蛋白。其溶解性较Mf有不同程度的提高。乳糖与Mf质量比为1：1，50℃反应48h后，肌原纤维乳糖蛋白在0．1m01／L NaCl溶液中的溶解性从反应前的18％提高到63％；55℃反应24h，其溶解性达到89％。结果表明．乳糖与鲢鱼肉Mf发生美拉德反应后生成的肌原纤维乳糖蛋白在低离子强度溶液中的溶解性得到了有效提高，乳糖能有选择性地与肌球蛋白重链相结合。