PCR在安祖花和白鹤芋属间杂交种早期鉴定中的应用

采用以PCR技术为基础的tRNALeuCAA基因内序列细胞核标记和内部改写空间2(ITS2)序列2种方法对7个安祖花属的红鹤芋(Anthurium andraeanum)和白鹤芋属的矮小苞叶芋(Spathiphyllum wallissii)的属间杂交种进行鉴定.使用tRNALeuCAA基因内序列细胞标记共扩增出13个位点,供试杂种中均无父本特异性谱带出现,仅在1个杂种中出现新的谱带,表明该杂种为真正的属间杂种.ITS2序列法扩增出28个位点,杂种谱带表现3种类型:无父本特异性谱带出现;出现新谱带;既出现父本特异性谱带又出现新谱带.应用ITS2序列法有6个假定杂交种均被鉴定为真正的属间杂交种.试验结果表明,tRNALeuCAA基因内序列细胞核标记和内部改写空间2(ITS2)序列2种方法可以用于属间杂种的鉴定.     

Prevention of colibacillosis in neonatal swine with a 4-pilus E coli bacterin

Of 12 pregnant swine (vaccinates) given a 4-pilus enterotoxigenic E coli (ETEC) bacterin (K88, K99, 987P, F41), all developed comparable or significantly higher serum and colostral antibody levels than those of 8 pregnant swine (controls) given a 3-pilus ETEC bacterin (K88, K99, 987P). When piglets were challenged with an ETEC strain bearing the F41 antigen, those from vaccinates had significantly lower mortality, less scours, less severe clinical signs and better weight gain than those from controls.     

棉胚珠继代培养纤维体系的建立

针对传统的棉胚珠培养方法因纤维在发育中途夭亡而不能用于研究次生壁增厚和强度形成的机理,本文建立了棉胚珠继代培养纤维体系,即根据花铃的形态特征选取Ⅱ类发育状态的胚珠作外植体,以14d为周期连续3次继代,在继代培养基中添加5g*L-1活性碳,并根据纤维发育不同阶段的特点调整植物生长物质的种类和浓度.结果使纤维重现了植株     

Folates Stability in Two Types of Rye Breads During Processing and Frozen Storage

High-performance liquid chromatography was used to study the stability of folate vitamers in two types of rye breads after baking and 16 weeks of frozen storage. Bread made using sourdough seeds contained less total folate (74.6 μg/100 g dry basis, expressed as folic acid) than the whole rye flour (79.8 μg/100 g dry basis) and bread leavened only with baker’s yeast (82.8 μg/100 g dry basis). Most importantly, it was generated by a significant decrease in 5-CH₃-H₄folate form. The baking process caused some changes in folate distribution. Storage of breads at -18°C for 2 weeks did not have a significant effect (p < 0.05) on total folates compared to the content directly after baking. After a 5-weeks storage period, a significant decrease (p < 0.05) in the content of total folates was recorded and it dropped on average by 14% for both type of breads. After a longer period of storage (16 weeks), a 25% loss of folates in the bread made with baker’s yeast and a 38% loss in the bread fermented with sourdough seeds was found. Retention of 5-CH₃-H₄folate and 10-HCO-H₂folate forms were much lower in the bread made with a sourdough addition than with baker’s yeast only.     

波兰樱桃产业发展概况

介绍了波兰的樱桃产量、面积和分布,主要品种和栽培模式,为中国的樱桃产业发展提供了系统的产业信息。     

Imidazenil,a new drug for the management of convulsions in organophosphate intoxication in rodents

The summary deals with the anti-convulsant and antilethal effects of a new benzodiazepine receptor partial agonist, imidazenil, in DFP intoxication. It has been demonstrated that imidazenil (2–5 mg kg⁻¹) significantly decreases convulsion intensity, rapidly inhibits seizure patterns in brain bioelectrical activity and significantly increases the anti-lethal efficacy of atropine plus obidoxime therapy. These effects are comparable to diazepam at 5 mg kg⁻¹. However, diazepam exhibits myorelaxant activity at therapeutic doses, which are only observed at 5–10 times the therapeutic doses of imidazenil.     

Hypolipidemic effects and absorption of citrus polymethoxylated flavones in hamsters with diet-induced hypercholesterolemia

Formulations containing citrus polymethoxylated flavones (PMFs), mainly tangeretin, or citrus flavanone glucosides, hesperidin and naringin, were evaluated for cholesterol-lowering potential in hamsters with diet-induced hypercholesterolemia. PMF metabolites were also investigated. Diets containing 1% PMFs significantly reduced serum total and very low-density lipoprotein (VLDL) + LDL cholesterol (by 19-27 and 32-40%, respectively) and either reduced or tended to reduce serum triacylglycerols. Comparable reductions were achieved by feeding a 3% mixture of hesperidin and naringin (1:1, w/w), implying lower hypolipidemic potency of the hesperidin/naringin vs PMFs. HPLC-MS analysis identified high serum, liver, and urine concentrations of tangeretin metabolites including dihydroxytrimethoxyflavone and monohydroxytetramethoxyflavone glucuronides and aglycones. Total liver concentrations of tangeretin derivatives corresponded to hypolipidemic concentrations of intact tangeretin in earlier experiments in vitro. This suggests that PMFs are novel flavonoids with cholesterol- and triacylglycerol-lowering potential and that elevated levels of PMF metabolites in the liver might be directly responsible for their hypolipidemic effects in vivo.     

Escherichia coli induces DNA double-strand breaks in eukaryotic cells

Transient infection of eukaryotic cells with commensal and extraintestinal pathogenic Escherichia coli of phylogenetic group B2 blocks mitosis and induces megalocytosis. This trait is linked to a widely spread genomic island that encodes giant modular nonribosomal peptide and polyketide synthases. Contact with E. coli expressing this gene cluster causes DNA double-strand breaks and activation of the DNA damage checkpoint pathway, leading to cell cycle arrest and eventually to cell death. Discovery of hybrid peptide-polyketide genotoxins in E. coli will change our view on pathogenesis and commensalism and open new biotechnological applications.     

读MBA到底有什么用？

一批评者：学会管理要靠实践．而不能靠课程有批评者认为：学会管理要靠实践,而不能靠课堂学习。MBA课程培养出来的是脱离实战的“皇太子”,虽然理论高深,但他们对将要经营的公司却一无所知。社会上真正需要的是靠实践成长起来的企业家,而不是靠书本理论培养出来的专业经理人。那么,MBA专业的目的到底是什么？