辽西半干旱地区春小麦农田水分循环特征的研究

一、研究地区的生态条件概述辽西属暖温带半干旱低山丘陵区,自然条件差,干旱少雨,干燥度为1.2左右,年均降水量为480.1mm,可能蒸散量为551.7mm,水分亏缺严重,而且70—75%的雨水降子6—8月份,春季偏少。舂季气温回升快,风速大,土壤水分蒸发损失严重,因此春旱频繁,并经常     

On the mechanism of activation of protein kinase FA (an activating factor of ATP·Mg-dependent protein phosphatase) in brain myelin

Protein kinase F_A (an activating factor of ATP·Mg-dependent protein phosphatase) has been characterized to exist in two forms in the purified brain myelin. One form of kinase F_A is spontaneously active and trypsin-labile, whereas the other form of kinase F_A is inactive and trypsin-resistant, suggesting a different membrane topography with active F_A exposed on the outer face of the myelin membrane and inactivu F_Q buried within the myelin membrane. When myelin was solubilized in 1% Triton X-100, all kinase F_A became active and trypsin-labile. Phospholipid reconstitution studies further indicated that when kinase F_A was reconstituted in acidic phospholipids, such as phosphatidylinositol and phosphatidylserine, the enzyme activity was inhibited in a dose-dependent manner, suggesting that kinase F_A interacts with acidic phospholipids which inhibit its activity. Furthermore, when myelin was incubated with exogenous phospholipase C, the inactive/trypsin-resistant F_A could be converted to the active/trypsin-labile F_A in a time- and dose-dependent manner. Taken together, it is concluded that membrane phospholipids play an important role in modulating the activity of kinase F_A in the brain myelin. It is suggested that phospholipase C may mediate the activation-sequestration of inactive/trypsin-resistant kinase F_A in the brain myelin through the phospholipase C-katalyzed degradation of acidic membrane phospholipids. The activation-sequestration of protein Kinase F_A may represent one mode of control modulating the activity of kinase F_A in the central nervous system myelin.     

Epitopes and hemagglutination binding domain on subgenus B:2 adenovirus fibers.

The adenovirus fiber serves as a ligand between the virus and the host cell receptor and manifests hemagglutination (HA) activity and antigenic domains. We have screened both the antigenic and immunogenic epitopes on the adenovirus fibers of subgenus B:2 by using recombinant fiber proteins (rfibers) expressed in Escherichia coli, synthesized peptides (P1 to P8), and the corresponding antisera. The results indicated that P4 (amino acids [aa] 201 to 220), P5 (aa 231 to 250), and P7 (aa 275 to 295) presented both antigenic and immunogenic epitopes in adenovirus type 11 prototype (Ad11p), Ad34a, and Ad11a fibers. P6 (aa 251 to 270) presented both epitopes in Ad11a fiber but only an antigenic epitope in other fibers. The C-terminal 20 amino acids of the fiber, corresponding to P8, manifested an epitope of low-level immunogenicity. P5, localized at the N-terminal aa 231 to 250, displayed an epitope that reacted with fibers of all the members of subgenus B analyzed. The rfibers of Ad11p and Ad34a displayed HA activity with monkey erythrocytes, though those of Ad11a did not. Mutagenesis of the rfibers revealed that neither the fragment replacements, 11p20211a, llp26011a,and 11a28011p, nor the Ad11p rfiber with the substitutions of Tyr-260-->H (Tyr260H)and Arg279Q displayed HA activity. The Ad11a fiber knob was sensitive to proteolytic digestion, whereas that of Ad11p was resistant. The results demonstrated that the decisive HA binding domain was presented at aa 260 to 280 and was conformation dependent. Nearby amino acids, aa 283 and 284, may also affect the HA function.     

以异源四倍体体细胞杂种为父本杂交培育三倍体柑桔植株的研究

以 3个柑桔原生质体融合而来的四倍体体细胞杂种为父本 ,与二倍体单胚性种柚子 (Citrusgrandis)以及单多胚混合型品种“华农本地早”桔 (C.reticulata)有性杂交 ,授粉后 90 d,发现种子干瘪 ,大部分种子的胚败育。将干瘪种子在 MT附加 1mg/L GA3 或 50 0 mg/L麦芽浸出物的培养基中 ,经培养抢救 ,有 2 5.6%的种子萌发成苗或继续进行胚的生长 ,后者进一步诱导能形成丛芽 ,经试管嫁接或诱导生根形成完整植株。共获得 6个组合 73棵完整植株 ,染色体数检查表明 ,2 0株为三倍体 (2 n=3x=2 7) ,32株为二倍体 (2 n=2 x=18) ,8株为非整倍体 ,其它 13株还有待于进一步检查。     

新疆亚鳞木（比较种）角质层特征

报道了产自江苏宜兴晚泥盆世五通组新疆亚鳞木（比较种）Ｓｕｂｌｅｐｉｄｏｄｅｎｄｒｏｎ ｃｆ． ｘｉｎｊｉａｎｇｅｎｓｅＳｕｎ）的表皮角质层用荧光分析显示的特征．该种茎干表皮角质层覆于叶座及叶座间隔带,其中间隔带角质层厚于叶座．表皮细胞在间隔带与叶座表现特征不同．间隔带中部,表皮细胞呈纵长的多边形,其纵长方向与茎干延伸方向相同,细胞壁略有弯曲．间隔带靠近叶座之表皮细胞,细胞壁直,形状类似于前者;但大小仅为前者的１／２左右,且其纵长方向逐渐向叶座边缘偏转．叶座表皮细胞呈近等多边形,有胞间隙．该种茎表皮无气孔     

RFLP mapping of QTLs for yield and related characters in rice (Oryza sativa L.)

Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F₂ populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143–RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7–11.5 g. QTL mapping in two populations with a common male parent is compared and discussed.     

A stochastic model for the sigmoidal behaviour of cooperative biological systems

A stochastic model for cooperative transitions in biological systems based on a Markov chain is proposed. This model requires only two parameters, the mean probability, p, and the coupling capacity, Deltap, which measure the probability of forming a new weak bond depending on the number of similar bonds already formed and it is also responsible for the transition. In this paper we show how the model works for a large number of identical molecules and how it can be useful for studying the noise around the centre of the transition where, increasing the degree of cooperativity, i.e. the number n in the well-known Hill equation, the width of the noise increases along with its fractal dimension. A simple relationship between the degree of cooperativity and the parameter Deltap is proposed, suggesting that the cooperativity of real biological transitions is related to the coupling capacity Deltap of the present model.     

苏云金芽孢杆菌δ-内毒素基因穿梭质粒的构建

在农业生产中长期使用化学农药已对环境和生态平衡造成一定破坏作用,同时有不少害虫也逐渐产生抗药性从而引起某些害虫的大流行,给农业生产带来巨大损失。应用苏云金杆菌杀虫蛋白基因(Bt基因)可构建具有抗虫作用的抗虫工程菌,这样通过拌种或植物叶面喷雾可达到快速、经济、有效的防治虫害的目的。国际上抗虫工程菌研究应用很快,如美国将BI基因转入到一种正常情况下定居在植物组织中的棒杆菌,将这种工程菌拌玉米种子,这样随植物生长该菌在植物体内大量繁殖,当玉米螟在茎和叶取食时,即因食用表达苏云金杆菌毒蛋白的工程菌而死亡。 田颖川等已克隆了苏云金芽孢杆菌内毒素基因CryIA(b)和CryIA(c)。本文将Bt基因CryIA(c)插入到大肠-枯草穿梭载体pBE-2中构建成Bt毒蛋白基因穿梭质粒pAMY,利用电穿孔法转人大肠杆菌DH5a,枯草芽孢杆菌B.subtilis BR151,IA511,野生型蜡状芽孢杆菌B.cereusa-47,短芽孢杆菌B.brevis A-5和枯草芽孢杆菌90-8,获得了具有较高杀虫活性的工程菌克隆。     

促葡萄糖转运蛋白基因家族的分子进化研究

葡萄糖转运蛋白是一个在结构上相似功能上不同的多基因家族（ＧＬＵＴ１－ＧＬＵＴ５）。由于这一组蛋白和体内的葡萄糖利用有关,因此被认为是糖尿病胰岛素抵抗（抗性）的一个候选基因。本文比较了不同种生物这一基因家族的氨基酸和核苷酸顺序;推测了亲水性和疏水性分布;计算了蛋白质和核苷酸的进化距离,并在此基础上构建了分子进化树。研究表明：这一基因家族具有高度的同源性、极为相似的亲水性和疏水性分布以及结构的对称性。提示这一基因家族起源于一个共同的祖先并可能通过基因的重复而形成。这一进化机制可能有利于氨基酸结构的稳定及抵抗突变的作用。由于邻元法构建的进化树其分支长度存在差异,提示在这一基因家族的进化过程中,各分支上的进化速率并不相同。蛋白质进化距离和核苷酸进化距离所构建进化树的差异提示了在基因组中可能存在隐匿替换。两种方法构建的进化树都提示了ＧＬＵＴ１、３、４在结构和功能上要更为保守。