质膜H~＋－ATP酶在玉米叶片渗透调节中的作用

干早胁迫下,玉米幼叶生长部位质膜Ｈ＋－ＡＴＰ酶活性显著上升,游离脯氨酸、可溶性糖和无机离子亦同时在玉米叶片生长部位大量积累,二者之间呈明显的正相关．质膜Ｈ＋－ＡＴＰ酶的专一性抑制剂Ｎａ３ＶＯ４在干旱胁迫下强烈抑制游离脯氨酸的积累,说明ＰＭＨ＋－ＡＴＰａｓｅ参与了玉米叶片的渗透调节过程．     

钙对生长素诱导的玉米胚芽鞘切段延长生长的影响

１０μｇ／ｇ的ＩＡＡ溶液强烈地促进玉米胚芽鞘切段的延长生长和质子分泌,但这两种效应的启动时间有别．Ｃａ２＋在高浓度下（２—５ｍｍｏｌ／Ｌ）强烈抑制ＩＡＡ诱导的延长生长,但在低浓度下（０．５ｍｍｏｌ／Ｌ）则有轻微的促进作用．ＩＡＡ增大质膜相对透性,而Ｃａ２＋则有稳定膜的作用,且适宜的浓度较低（０．５ｍｍｏｌ／Ｌ）．     

菜蚜二项式抽样设计及其精度分析

１９９０～１９９２年间对杭州市郊区青菜上桃蚜（Ｍｙｚｕｓｐｅｒｓｉｃａｅ）、萝卜蚜（Ｌｉｐａｐｈｉｓｅｒｙｓｉｍｉ）及其混合种群的田间近１００组调查数据,利用每样方（株）虫口不超过数阈值Ｔ（分别为０、１、５、１０、２０、３０、４０）头蚜虫的植株比例（ＰＴ）与种群密度（ｍ,头·株－１）的关系,通过拟合经验公式ｌｎ（ｍ）＝ａ＋ｂｌｎ［－ｌｎ（ＰＴ）］而设计的二项式抽样．通过对三者不同数阈值（Ｔ）的回归决定系数（ｒ２）、种群密度的回归估计方差（Ｖａｒ（ｍ））、抽样精度（以ｄ表示）和实际应用等的比较,结果表明当桃蚜种群处于较高密度即ｍ≥１０时,其理想的Ｔ值为３０;当萝卜蚜种群处于较高密度即ｍ≥５时,其理想的Ｔ值为１０;而它们的混合种群未得到其理想的Ｔ值．数阈值Ｔ为３０和１０可分别用于桃蚜和萝卜蚜的二项式抽样设计．而传统的二项式抽样即０～１抽样由于应用于小白菜上菜蚜的抽样设计时产生很大的误差,不宜采用．     

铽离子与RNA的荧光反应及RNA测定的研究

核糖核酸（ＲＮＡ）与稀土铽离子在ｐＨ５．０～６．５条件下能形成具有较强荧光的络合物,其激发峰在２８８ｎｍ处,发射峰为４９４ｎｍ及５４５ｎｍ处．ＲＮＡ在０．１～１０ｍｇ／Ｌ范围内与其荧光强度呈线性关系,其检出限为６．０×１０￣（－８）ｍｏｌ／Ｌ．腺苷酸,尿苷酸,胞苷酸对ＲＮＡ的干扰比较小,因此可在其存在下选择性地测定ＲＮＡ．     

Cell signaling and heat shock protein expression

Exposure of cells and organs to heat shock is associated with numerous changes in various cellular metabolic parameters and overexpression of proteins collectively known as heat shock proteins (HSP). In this communication we review the cell-signaling events that are altered in response to heat shock as they relate to the subsequent induction of HSP 70 kd (HSP-70) expression. We also review the mechanisms by which HSP-70 is involved in conferring cytoprotective effects. The possibility of altering HSP expression through manipulations of the cell-signal process has clinical importance.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army or Department of Defense.     

The role of context on alpha-helix stabilization: host-guest analysis in a mixed background peptide model.

The helix content of a series of peptides containing single substitutions of the 20 natural amino acids in a new designed host sequence, succinyl-YSEEEEKAKKAXAEEAEKKKK-NH2, has been determined using CD spectroscopy. This host is related to one previously studied, in which triple amino acid substitutions were introduced into a background of Glu-Lys blocks completely lacking alanine. The resulting free energies show that only Ala and Glu- prove to be helix stabilizing, while all other side chains are neutral or destabilizing. This agrees with results from studies of alanine-rich peptide modela, but not the previous Glu-Lys block oligomers in which Leu and Met also stabilize helix. The helix propensity scale derived from the previous block oligomers correlated well with the frequencies of occurrence of different side chains in helical sequences of proteins, whereas the values from the present series do not. The role of context in determining scales of helix propensity values is discussed, and the ability of algorithms designed to predict helix structure from sequence is compared.     

滇藏常绿杜鹃亚属的修订

常绿杜鹃亚属Subgenus Hymenanthes是由K.Koch（1872）根据Blume（1826）建立的Genus Hymenanthes改级组合而成。但长期以来人们一直沿用了Maximowicz（1870）所建立的、后由Koehne（1893）修订过的Subgenus Eurhododendron这一亚属名称,直到最近D.F.Chamberlain（1978,1979,1982）对该亚属的名称才作了正式订正。     

Production of Ethanol from d-Xylose by Using d-Xylose Isomerase and Yeasts

d-Xylulose, an intermediate of d-xylose catabolism, was observed to be fermentable to ethanol and carbon dioxide in a yield of greater than 80% by yeasts (including industrial bakers' yeast) under fermentative conditions. This conversion appears to be carried out by many yeasts known for d-glucose fermentation. In some yeasts, xylitol, in addition to ethanol, was produced from d-xylulose. Fermenting yeasts are also able to produce ethanol from d-xylose when d-xylose isomerizing enzyme is present. The results indicate that ethanol could be produced from d-xylose in a yield of greater than 80% by a two-step process. First, d-xylose is converted to d-xylulose by xylose isomerase. d-Xylulose is then fermented to ethanol by yeasts.     

温度对桃蚜、萝卜蚜体重及种群参数的影响

桃蚜Myrus perslcae、萝卜蚜Lipaphis crystml在能正常产仔的整个恒温范围内,成蚜和新产仔蚜体重随温度的变化都符合二次抛物线,但体重最高值出现较低的温度下．即体重变化主要表现为随温度升高而下降的趋势．在组建蚜虫的生命生殖力表时,以新产仔蚜体重对其在各温度下的生殖事进行校正。并未对计算所得的内禀增长能力rm值及其随温度的变化情况产生明显的影响,不仅没有提供新的信息。相反。这一方法使计算所得rm的值含义模糊。故建议不予采用。