锗对水稻萌芽期的生理效应

将水稻（ＯｒｙｚａｓａｔｉｖａＬ．）种子浸于从０到３ｍｇ·Ｌ－１不同浓度梯度的ＧｅＯ２溶液中,测量其生理指标：呼吸强度,可溶性糖含量,淀粉酶活性等。发现在浸种的前期,ＧｅＯ２对以上各项生理指标均有促进作用,而随着浸种时间的延长,促进逐渐减弱并转为抑制,淀粉酶同功酶电泳则表明,植物体内复杂多样的同功酶系统在一定范围内对ＧｅＯ２的毒害作用有某种程度的适应与调节能力     

秋水仙碱诱导重瓣大岩桐(Sinningia speciosa)多倍体的研究

以重瓣大岩桐叶片为外植体,经秋水仙碱处理得到大量的多倍体植株。在培养基中加入秋水仙碱２０ｍｇ Ｌ＾－１处理一周,可使重瓣大岩桐的诱变率达到６２．５％,对再生植株进行形态学观察表明,多倍体植株比二倍体的茎粗壮,叶片增大,加厚。细胞学鉴定四倍体染色体数为２ｎ＝４ｘ＝５２,而二倍体的染色体数为２ｎ＝２６。     

Methods for the identification and analysis of l-altrose in bacterial polysaccharides

Abstract The two genes ( cfxP ) for phosphoribulokinase (PRK) in Alcaligenes eutrophus H16 are simultaneously expressed, resulting in the formation of PRK isoenzymes. The isoenzymes are structurally and immunoligically closely related. Their subunits differ only slightly in size. M _rs of 33 000 and 32 500 were determined for the chromosomally and megaplasmid pHF1-encoded subunits, respectively. The pHG1-encoded gene, cfxP , was cloned in Eschirichia coli and expressed under the cloned in Escherichia coli and expressed under the control of the lac promoter of pUC9 vectors. Native PRK with subunits of M _r 32 500 was formed, confirming the identity and functionality of cfxP _p . However, the recombinant PRK had a significantly lower specific activity than the authentic enzyme.     

Gene Diversity and Genetic Differentiation in Natural Populations of Picea koraiensis

Vertical slab polyacrylamide gel electrophoresis was used to examine inheritance of four isoenzymes in megagametophytes of Picea koraiensis. Gene diversity and genetic differentiation in four natural populations of P. koraiensis in Northeastern China were analyzed at six loci coding for four enzyme systems. The proportion of loci polymorphism in population was 0.5. The average expected heterozygosity of all samples was 0. 314, and the average observed heterozygosity of all samples was 0. 316. The average number of alleles detected per locus was 2.50. The effective number of alleles per locus was 1. 71. Measurement of gene diversity for the six loci showed a 0. 0059 significance of interpopulation differentiation. More than ninety-nine percent of the total gene diversity resided within population. The mean genetic distance over all pairs of P. koraiensis was 0. 0110.     

过氧化物同工酶在樟子松种源区划上的应用

采用电脉的方法得到樟子松过氧化物同工酶谱带,对其谱带进行方差分析、主成分分析和聚类分析,根据分析结果可将樟子松十个种源划为两个大的种源区,4个小的种源区。大的种源区为阿尔山、罕达盖为代表的沙土种源和以金山、塔河为代表的山地种源。小的种源区是分别以漠河、图强、红花尔基和卡伦山为代表的各自独立的种源区。区划结果与地理气象因子区划结果基本一致。     

高原鼠兔乳酸脱氢酶同工酶对低氧环境的应答

用聚丙酰胺凝胶薄层电泳和紫外光谱法,研究与分析高原鼠兔(Ochotona curzoniae)在天然及模拟低氧条件下,心脏、肝脏、肾脏及骨骼肌4种组织的乳酸脱氢酶(LDH)同工酶的酶谱和其酶活力的变化。     

Role of Protein Kinase C (PKC) in Agonist-Induced α-Opioid Receptor Down-Regulation

Abstract : Phosphorylation of specific amino acid residues is believed to be crucial for the agonist-induced regulation of several G protein-coupled receptors. This is especially true for the three types of opioid receptors (μ, δ, and α), which contain consensus sites for phosphorylation by numerous protein kinases. Protein kinase C (PKC) has been shown to catalyze the in vitro phosphorylation of μ- and δ-opioid receptors and to potentiate agonist-induced receptor desensitization. In this series of experiments, we continue our investigation of how opioid-activated PKC contributes to homologous receptor down-regulation and then expand our focus to include the exploration of the mechanism(s) by which μ-opioids produce PKC translocation in SH-SY5Y neuroblastoma cells. [d Ala²,N-Me-Phe⁴,Gly-ol]enkephalin (DAMGO)-induced PKC translocation follows a time-dependent and biphasic pattern beginning 2 h after opioid addition, when a pronounced translocation of PKC to the plasma membrane occurs. When opioid exposure is lengthened to >12 h, both cytosolic and particulate PKC levels drop significantly below those of control-treated cells in a process we termed “reverse translocation.” The opioid receptor antagonist naloxone, the PKC inhibitor chelerythrine, and the L-type calcium channel antagonist nimodipine attenuated opioid-mediated effects on PKC and μ-receptor down-regulation, suggesting that this is a process partially regulated by Ca²⁺-dependent PKC isoforms. However, chronic exposure to phorbol ester, which depletes the cells of diacylglycerol (DAG) and Ca²⁺-sensitive PKC isoforms, before DAMGO exposure, had no effect on opioid receptor down-regulation. In addition to expressing conventional (PKC-α) and novel (PKC-ε) isoforms, SH-SY5Y cells also contain a DAG-and Ca²⁺-independent, atypical PKC isozyme (PKC-ξ), which does not decrease in expression after prolonged DAMGO or phorbol ester treatment. This led us to investigate whether PKC-ξ is similarly sensitive to activation by μ-opioids. PKC-ξ translocates from the cytosol to the membrane with kinetics similar to those of PKC-α and ε in response to DAMGO but does not undergo reverse translocation after longer exposure times. Our evidence suggests that direct PKC activation by μ-opioid agonists is involved in the processes that result in μ-receptor down-regulation in human neuroblastoma cells and that conventional, novel, and atypical PKC isozymes are involved.     

Inhibitory effect of proteinaceous seed extract of three Iranian wheat cultivars on Eurygaster integriceps (Sunn pest) digestive enzymes

Abstract

To investigate interaction between proteinaceous extracts of three Iranian wheat cultivars and digestive enzymes of Sunn pest, a population of adult insects was collected in summer from a wheat field located in Borkhar Region, Isfahan, Iran. Seed proteins were extracted by 0.15?M NaCl solution and partially purified using ammonium sulphate. Spectrophotometric assays were implemented to determine enzyme activities. Results indicated cultivar- and dose-dependent efficacy of seed protein extracts. Inhibition percentages of α-amylase, α-glucosidase, β-glucosidase and proteolytic activities at concentration of 32?μg/mL and saturation percentage of 70% ammonium sulphate were 54, 37, 25 and 59% by Hamoon, 16, 28, 18 and 19% by Karkheh and 15, 16, 15 and 23% by Dena, respectively. Zymography also confirmed the effect of inhibitors on α-amylase activity. Among wheat cultivars, Hamoon has the highest biological activity against Sunn pest major digestive enzymes and could contribute towards the development of new insect pest control strategies.     

Proteolytic profile in the larval midgut of Chilo suppressalis Walker (Lepidoptera: Crambidae)

Chilo suppressalis is a key constraint on production of rice. The current research was conducted to study the types of digestive proteases in the larval midgut of C. suppressalis. It was found that activity of total digestive proteases increased from the first to the fifth larval instars, which showed different nutritional requirements. Four types of proteinases and two types of exopeptidase were identified so that their activities from the highest to the lowest activities is trypsin‐like, chymotrypsin‐like and elastase for proteinases, and amino and carboxypeptidases for exopeptidases. Meanwhile, just one type of cysteine protease, cathepsin D, was determined in the fourth and fifth instar larvae. The optimal pH for activity of total protease was found to be pH 9–10 and optimal temperature was observed to be 35–40°C, where there was the highest proteolytic activity. Some specific inhibitors of proteases including PMSF, TLCK, TPCK, DTT, E‐64, cystatin, phenanthroline and EDTA were used to confirm the types of proteases in the midgut of C. suppressalis.