PRRSV山西株ORF5和Nsp2基因序列分析

采用RT-PCR方法对2009—2011年山西省分离的5株猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus,PRRSV）的ORF5和Nsp2（2503～3269nt）基因进行克隆和测序,并对其基因序列和推导的氨基酸序列与国内外毒株进行了同源性分析。序列分析结果显示,5株分离株Nsp2基因与国内分离的PRRSV变异株（JXA1、HuN、HUN4、HUB1）的序列同源性最高,为96．8％～98．2％,且缺失位置一致,均存在2个位点30个氨基酸缺失;ORF5基因大小为603bp,编码200个氨基酸,第13、151位均为具有强毒特性的精氨酸（R）,137位为丝氨酸（S）,表明这5株均为野毒株,与国内分离的PRRSV变异株（JXA1、HuN、HUN4、HUB1）毒株的序列同源性最高,为96．5％～98．0％。结果表明,山西省内目前流行的PRRSV为Nsp2缺失30个氨基酸的变异毒株。     

Effect of dietary Schizochytrium microalga oil and fish oil on plasma cholesterol level in rats

The purpose of the study was to test the hypothesis that the dietary oils with different content of n‐3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) affect plasma lipid level in rats in a different degree. The diets with 6% of fish oil (FO) and Schizochytrium microalga oil (SchO; EPA+DHA content in the diets 9.5 + 12.3 and 2.6 + 29.5% of the sum of total fatty acids, respectively) were used; the diet with 6% of safflower oil (high content of n‐6 PUFA linoleic acid, 65.5%; EPA+DHA content 0.7 + 0.9%) was used as a control. The difference between FO and SchO was established only in the case of plasma triacylglycerol (TAG) level: plasma TAG of the FO‐fed rats did not differ from the control rats (p > 0.05), while SchO decreased (p < 0.05) plasma TAG to 46% of the control. On the other hand, FO and SchO decreased (p < 0.05) total plasma cholesterol (TC) in rats in the same extent, to 73% of the control. Regarding the underlying mechanisms for the TC decrease, both SchO and FO up‐regulated hepatic Insig‐1 gene (181 and 133% of the control; p < 0.05), which tended (p = 0.15 and p = 0.19 respectively) to decrease the amount of hepatic nSREBP‐2 protein (61 and 66% of the control). However, neither SchO nor FO influenced hepatic 3‐hydroxy‐3‐methyl‐glutaryl‐CoA reductase gene expression (p > 0.05); SchO (but not FO) increased (p < 0.05) low‐density lipoprotein receptor mRNA in the liver. It was concluded that the decrease of total plasma cholesterol might be caused by an increased cholesterol uptake from plasma into the cells (in the case of SchO), but also by other (in the present study not tested) mechanisms.     

益生菌大肠杆菌Nissle 1917抗逆性能、猪肠上皮细胞黏附率及抑菌效果研究

本试验旨在研究益生菌大肠杆菌Nissle 1917(Ec N)抗逆性能、猪肠上皮细胞黏附率及抑菌效果。采用体外法对Ec N进行生长曲线绘制和耐酸、耐胆盐、耐热性能的测定;以猪肠上皮细胞IPEC-J2细胞为体外细胞模型,考察了Ec N对该细胞的黏附率以及对致病菌大肠杆菌K88的黏附抑制率;同时通过蛋白质印迹法检测了Ec N对IPEC-J2细胞β-防御素-2和Toll样受体4的水平的影响。结果表明:1)Ec N对高酸、高胆盐和高温环境具有一定耐受能力。2)Ec N对IPEC-J2细胞的黏附作用以对数期最佳,黏附率达33.96%,显著高于迟缓期、稳定期和衰亡期(P0.05)。3)Ec N对致病菌大肠杆菌K88具有良好的抑制效果,黏附抑制率达87.84%。4)Ec N还能上调IPEC-J2细胞β-防御素-2和Toll样受体4水平。结果提示,益生菌Ec N具有较好的抗逆性能,能够良好地黏附猪肠上皮细胞,对致病菌大肠杆菌K88具有良好的抑制作用。     

影响降解菌W2修复异噁草酮污染土壤的三种因子的优化

［目的］ 确定降解菌W2对土壤中异噁草酮的最优生物修复条件。［方法］ 采用3因素5水平正交旋转组合设计,室外盆栽生物测定方法,研究降解菌W2接种量、土壤含水量和肥料添加量3种田间可控因子对降解菌W2修复异噁草酮污染土壤效果的影响。［结果］ 确定修复条件的优化数学回归模型为:y=62.363 9+5.872 8×C1-4.494 1×C2C3-1.262 1×C21-4.076 7×C22,不同因子对土壤修复影响大小顺序依次为土壤含水量、肥料添加量、降解菌W2接种量。［结论］ 降解菌W2对土壤中异噁草酮的最优生物修复条件为：降解菌W2接种量8.19～11.81 mL/kg（A650=0.4）,土壤含水量18.6%～20.84%,肥料添加量1.83～2.52 g/kg。在此范围内降解菌W2对异噁草酮有效成分浓度为500 μg/kg的风干土壤30 d后的降解率可达60%以上,可接近该修复天数的理论极值65.56%。     

猪圆环病毒2型山东分离株全基因组的克隆与序列分析

根据猪圆环病毒2型(PCV-2)全基因组序列,设计一对特异性引物,从疑似断奶仔猪多系统衰竭综合征(PMWS)病料中扩增出PCV-2基因组DNA,将基因片段克隆于pMD18-T载体,筛选获得含有相应片段的阳性重组质粒pMD18-T-PCV-2。对筛选出的阳性质粒进行测序。结果表明,PCV山东株的全基因组为1 767 bp,与国内外毒株核苷酸同源性高达99.6%。     

上海市猪圆环病毒2型全基因组的克隆与序列分析

参照国外发表的猪圆环病毒2型(Porcine circovirus type 2,PCV-2)全基因组序列,设计合成了1对特异性引物,从上海市临床病料中提取PCV-2基因组DNA,进行PCR全基因扩增。回收PCR产物,将其插入pMD18-T载体,并对筛选出的阳性质粒进行测序。应用DNAStar序列分析软件,对所测PCV-2序列与GenBank中登录的国内外PCV-2毒株进行同源性比较。结果显示,PCV-2上海株与国内外毒株的核苷酸同源性高达95.0%～100%。进化树分析结果显示,其中9株PCV-2病毒属于PCV-2b亚型,3株PCV-2病毒属于PCV-2a亚型,且9株PCV-2b亚型毒株部分核苷酸位点显示其属于强毒力毒株。研究表明,上海市PCV-2感染以PCV-2b亚型为主,且氨基酸位点表明其具有较高的毒力。     

Effects of the sodium‐glucose cotransporter 2 (SGLT2) inhibitor velagliflozin,a new drug with therapeutic potential to treat diabetes in cats

Sodium‐glucose cotransporter 2 (SGLT2) inhibitors are used in the treatment of human diabetics. They increase glucose excretion and correct hyperglycemia. We examined the investigational SGLT2 inhibitor velagliflozin in two groups of six neutered adult obese cats (equal gender distribution). Placebo (Pl) or drug (D; 1 mg/kg) was administered for 35 days. Routine blood examinations, fructosamine, beta‐hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), glucagon, adiponectin, and leptin were measured before and after treatment, also water intake, and urinary electrolytes, glucose, and volume. Indirect calorimetry, an intravenous glucose tolerance test (IVGTT; 0.8 g/kg) and insulin tolerance test (IVITT) were conducted. All cats tolerated treatment well. Significant changes with D included a decrease in the respiratory exchange ratio, an increase in cholesterol, a small increase in albumin, and a rise in BHB and NEFA. Glucose clearance was unaltered, although less insulin was secreted during the IVGTT (p = .056) suggesting improved insulin sensitivity. IVITT was unchanged. Treatment did not affect glucagon, leptin, or adiponectin. Water intake, urine output, urinary glucose excretion, and the glucose/creatinine ratio but not urinary electrolytes were significantly higher post‐D. We conclude that velagliflozin is a promising drug, which increases urinary glucose excretion in cats and could thereby be beneficial for the treatment of hyperglycemia.     

无籽西瓜嫁接稀植配套新品种兴科无籽2号的选育

兴科无籽2号是安徽省无子西瓜研究所1998年以MR四倍体为母本、XR8二倍体为父本杂交,1999 年育成的无籽西瓜新品种。该品种中晚熟,果实黑皮红瓤,中心可溶性固形物含量11％-12％,耐重茬,耐湿、耐贮运。生长势和分枝力强,1株多果和连续坐果习性好。667m2栽植200-300株,单株结果3-5个,单果重5-7kg,产量 4000-5000kg／667m2,是较理想的嫁接稀植技术配套品种。适合华南、长江流域和淮河流域栽培。     

黄河源区“黑土滩”退化草地CO2排放研究

采用静态箱-气相色谱法,对黄河源区“黑土滩”退化草地CO2释放特征的研究结果表明：“黑土滩”3种不同处理：“黑土滩”植被-土壤系统呼吸（BC）,土壤呼吸（BJ）和土壤微生物呼吸（BL）的CO2释放速率日变化具有相似性,均呈现出明显的单峰型特点,且白天大于夜间;CO2释放速率季节动态变化明显,且3者的变化趋势基本一致;“黑土滩”植被-土壤系统呼吸与地表温度及5cm地温呈极显著的正相关性（P〈0．01）;而土壤微生物呼吸与0～10cm土壤水分含量相关显著（P〈0．05）。