Utilization of β-carotene fromSpirulina platensis by rats

The availability of -carotene from Spirulina as compared to standard all trans -carotene was studied by the liver and kidney vitamin A storage method. After 21 days of vitamin A depletion, the rats were repleted with -carotene from Spirulina and a standard source at two dietary levels (60 and 120 µg/day) for a 10 day period. At lower levels, the liver storage levels of vitamin A and the percent of -carotene absorption were comparable to those of the standard. At higher levels both these parameters of the Spirulina fed group were significantly (P<0.01) inferior to the standard source fed group. However, the Spirulina fed group showed better (P<0.05) growth than the standard fed group did at both low and high levels of feeding.     

大学生社团服务新农村建设研究初探

大学生社团组织学生参与新农村建设,是大学生走出校园、服务地方、锻炼能力的有效途径.文章分析了大学生社团服务社会主义新农村建设的必要性和优势,最后从形成和强化多方受益机制、建立和加强制度保障机制、建立和健全激励机制等三个方面阐明建立大学生社团服务新农村建设的长效机制的途径.     

（m，l）秩幂等矩阵和（m，l）幂等矩阵的特性研究

如果存在自然数m,l（m〉l）使r（A^m）=r（A^l）,称A为（m,l）秩幂等矩阵;当A^m=A^l时,称A为（m,l）幂等矩阵依据矩阵的幂等性与秩幂等性不随数域的改变而改变这一基本事实,应用Jordan标准形的性质,得到了这两类既有区别又有密切联系的矩阵类的特性刻画．     

温室甜瓜膜下滴灌初花期适宜蒸发皿系数研究

在日光温室膜下滴灌条件下,采用E20蒸发皿的水面蒸发量控制灌溉,研究了不同蒸发皿系数(Kcp=0.45,0.6,0.75,0.9)对初花期甜瓜生长、生理特性的影响. 结果表明:(1)水分处理对温室膜下滴灌甜瓜15 cm处地温产生了显著影响,其中T2(0.6) 与T3(0.75)处理的地温对甜瓜生长较为有利;(2)水分处理对甜瓜叶片扩展和叶面积大小影响较大,以2 d为灌溉周期,蒸发皿系数(Kcp)采用0.6有利于甜瓜叶片扩展,而且植株叶面积最大;(3)从甜瓜株高、茎粗/株高、总生物量与根冠比、叶片水分状况、叶片光合生理指标等综合分析,蒸发皿系数Kcp采用0.6(T2)都要优于其它水分处理.     

考虑剪切变形影响的桩基m法计算理论

考虑桩基的剪切变形影响,利用单广义位移深梁理论,建立了桩基m法的计算方法,导出了水平位移、转角、弯矩和剪力的初参数表达式和无量纲参数函数的统一表达式,根据桩底边界条件建立了初参数解的计算公式;给出了无量纲参数函数随换算深度和弯剪刚度比的变化图形。研究表明,换算深度小于3.0时,弯剪刚度比对无量纲参数函数影响较小,换算深度大于4.0时,弯剪刚度比对无量纲参数函数影响的趋势非常明显,桩基剪切变形的影响程度与桩的边界条件有关。算例结果表明,桩身的剪切变形有增大桩顶水平位移、提高弯矩零点位置、改变弯矩分布特征、扩大桩侧土压力大小等影响。     

渗透胁迫下邻羟基苯甲酸对1年生杉木幼苗叶绿素含量的影响

为研究渗透胁迫下杉木自毒物质邻羟基苯甲酸（SA）对杉木幼苗的毒害作用,用不同浓度的聚乙二醇模拟干旱处理,通过水培方法研究在渗透胁迫下不同浓度（50,100,200 mg/L）杉木自毒物质SA对1年生杉木幼苗叶绿素含量的影响.结果表明：在轻度（-0.3 MPa）、中度（-0.5MPa）、重度（-0.7MPa）渗透胁迫下,杉木幼苗叶绿素含量总体呈下降趋势,且随着渗透胁迫程度的增加,叶绿素含量下降加速.在渗透胁迫下,当自毒物质浓度达200 mg/L时,与对照相比,在第7,14,21 d时,其叶绿素含量分别下降15.39%,25.78%,41.89%.     

m6A甲基化酶相关基因在牛骨骼肌生成中的表达

【目的】近年来,RNA m⁶A甲基化修饰在肌肉发育中的作用不断被发现,通过探究m⁶A甲基化酶相关基因,包括METTL3,METTL14,WTAP,FTO和ALKBH5,在牛肌肉组织以及骨骼肌卫星细胞(skeletal muscle satellite cells, SMSCs)增殖和分化过程中的表达,同时分析体外成肌分化过程中m⁶A甲基化水平的变化,为阐明m⁶A修饰在骨骼肌发育中的作用及机制提供参考。【方法】使用实时荧光定量PCR(RT-qPCR)技术检测m⁶A甲基化酶相关基因在新生和成年牛不同部位骨骼肌中的表达。随后在秦川牛肉用新品系背最长肌中分离SMSCs,通过生长曲线、免疫荧光和RT-qPCR技术验证SMSCs的增殖和成肌分化功能,使用RT-qPCR检测m⁶A甲基化酶相关基因在SMSCs增殖期24、36、48、60、72 h和分化第0、2、4、6、8天中的时序表达谱。最后利用LC-MS/MS和Dot blot技术检测SMSCs分化过程中m^6...     

肠炎沙门氏菌鞭毛蛋白基因快速克隆和鉴定

以提纯的肠炎沙门氏菌染色体ＤＮＡ为材料,在一对含有ＣＵＡＣＵＡＣＵＡＣＵＡ的特殊引物引导下,应用ＰＣＲ扩增出鞭毛蛋白基因ｆｌｉＣｇ,ｍ,约１．８ｋｂ左右大小,然后以ＵＤＧ法快速克隆到质粒ｐＡＭＰ１０中,转化第１宿主大肠杆菌ＴＧ１或大肠杆菌ＤＨ５α,在氨苄青霉素平板上筛选转化子,小量制备重组质粒ＤＮＡ,再转入第２宿主大肠杆菌ＬＣ－２ａ（ｈａｇ－,ｒｅｃＡ－）,所有转化子均出现动力。其中的一个克隆ｐＡＭＰ·ＧＭ经动力和动力抑制试验、血清学试验、鞭毛电镜观察及部分序列测定,均证实ｐＡＭＰ·ＧＭ中载有肠炎沙门氏菌鞭毛蛋白基因ｆｌｉＣｇ,ｍ。ｆｉｌＣｇ,ｍ克隆成功为寻求肠炎沙门氏菌防制新方法奠定了基础,研究中建立的快速克隆策略为广泛、深入地开展ｆｌｉＣ研究提供了便捷的新途径。     

Oil and protein quality of groundnut mutants

Variability in oil quality was observed in four groundnut mutants (TG-1, TG-3, TG-14, TG-16) induced by -irradiation. The fatty acid composition of the mutants differed from their parent Spanish Improved. All the mutants had lower linoleic and higher oleic acid than the parent Spanish Improved. TG-3 and TG-14 had substantially higher linoleic acid and lower oleic acid as compared with TG-1 and TG-16. Other fatty acids also showed minor variation amongst mutants and Spanish Improved. The ratio of oleic to linoleic acid, which is an index of oil stability, was 2.7 and 3.3 fold respectively in TG-16 and TG-1 as compared with Spanish Improved.Protein percent in TG-1, TG-14 and TG-16 was higher than in Spanish Improved. Amino acid analysis of protein from mutants indicated decreases in methionine and cystine and an increase in tryptophan as compared with Spanish Improved. Other amino acids did not show any major variation between the mutants and Spanish Improved. In all varieties except TG-16, lysine was the first limiting amino acid; threonine was second limiting in all mutants. The essential amino acid content per kernel was higher in mutants than in Spanish Improved.