姜黄属植物过氧化物酶同工酶的研究

用聚丙烯酰胺凝胶电泳分析姜黄属14种(28个样品)植物的过氧化物酶同工酶。结果表明属内种间有明显的酶谱差异,各种都有特征酶谱。根据酶谱特征及酶谱距离,结合根茎颜色,可把14个种分成三群:第一群,根茎黄色至深红色,有姜黄、毛姜黄、郁金、印尼莪术、C.petiolata和C.sP.(2);第二群,根茎灰白色,有广西莪术、大莪术和温郁金;第三群,根茎浅黄而间淡蓝色或深蓝色,有莪术、顶花莪术、细莪术、C.aeruginosa及C.zedoaria。研究结果还表明:1.国产莪术的酶谱与从美国引入的C.zedoaria和C.aeruginosa均不相同,而与引自新加坡的C.Phaeocaulis一致;2.不同形态的广西莪术具有完全一致的酶谱;3.温郁金与郁金的酶谱有差异。     

L615白血病鼠胸腺和脾脏淋巴细胞脱氢酶同工酶的研究

应用聚丙烯酰胺凝胶电泳法对比研究了纯系６１５鼠和Ｌ６１５可移植性淋巴细胞型白血病鼠胸腺和脾脏淋巴细胞的葡萄糖－６－磷酸脱氢酶同工酶（ＥＣｌ．１．１．４９,Ｄ－葡萄糖－６－磷酸：ＮＡＤＰ氧化还原酶,Ｇ６ＰＤ）和乳酸脱氢酶同工酶（ＥＣｌ．１．１．２７,Ｌ－乳酸：ＮＡＤ氧化还原酶,ＬＤＨ）。并应用定量细胞化学法对ＬＤＨ和６ＰＤ全酶活性进行了测定。结果：在Ｌ６１５白血病鼠胸腺淋巴细胞中（白血病细胞占４０％）,Ｇ６ＰＤ同工酶谱显示异常,全酶活性明显增高、ＬＤＨ同工酶谱及全酶活性未发生明显变化。Ｌ６１５白血病鼠脾脏淋巴细胞中（白血病细胞占８４％）,Ｇ６ＰＤ和ＬＤＨ同工酶谱均显示异常,同时全酶活性也明显增强。提示：Ｇ６ＰＤ对白血病细胞的恶性增殖和浸润似乎更为敏感。     

湛江红橙准分子激光处理的诱变效应研究

准分子激光对湛江红橙无性繁殖材料（枝条）辐照的结果表明：在适当剂量辐照下,可以产生少核或无核的变异,并且可改善橙果的风味品质。同工酶的分析也显示出,准分子激光已能引起湛江红橙的遗传变异。     

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。     

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.     

The occurrence of chloroplastic and cytosolic isoenzymes of phosphoglycerate kinase in a range of plant species

The chloroplastic and cytosolic isoenzymes of phosphoglycerate kinase (PGK; EC 2.7.2.3) of leaves from 18 of a broad range of 21 vascular plant species were separated by either standard or modified anion-exchange Chromatographic procedures. Immunoprecipitation of the isoenzymes with antisera raised against barley chloroplastic and cytosolic PGK isoenzymes showed that the chloroplastic isoenzymes resemble the chloroplastic isoenzymes of other species more closely than the cytosolic isoenzyme of the same species and vice versa for the cytosolic isoenzymes. Each of the two cyanobacterial species tested, yielded only a single PGK fraction on anion-exchange chromatography and gave no reaction with antisera raised against the barley isoenzymes. The cyanobacteria are presumed to contain only a single PGK which is not closely related to either of the barley PGK isoenzymes. In all of the investigated leaf extracts the catalytic activity of the cytosolic PGK was exceeded by that of the chloroplastic PGK with the ratio for many of the C₃ plants falling within the range 595 to 1585 (cytosolic: chloroplastic). The relative amounts of cytosolic PGK activity appeared to be greater in older leaves, in C₄ and CAM plants and in ferns.Abbreviations CAM crassulacean acid metabolism - pgk phosphoglycerate kinase This work was supported by the Science and Engineering Research Council (grant no. GR/E54504) and also the King's College London Research Strategy Fund.     

Leishmania (Kinetoplastida): species typing with isoenzyme and PCR-RFLP from cutaneous leishmaniasis patients in Ethiopia

Cutaneous leishmaniasis (CL) is an increasing public health problem in Ethiopia. There is a concern that it is spreading with increased incidence. In this study, we used isoenzyme electrophoresis and internal transcribed spacer one (ITS1) PCR-RFLP techniques to identify Leishmania species from CL patients in Ethiopia. We obtained isolates from 55 localized cutaneous leishmaniasis (LCL), 3 diffused cutaneous leishmaniasis (DCL) and 36 biopsy samples from 34 LCL and 2 DCL cases from All Africa Leprosy and Tuberculosis Rehabilitation and Training Center (ALERT) and clinically diagnosed CL cases from Ochollo village. Both isoenzyme and ITS1 PCR-RFLP techniques showed that Leishmania aethiopica (L. aethiopica) was the aetiologic agent in all cases. Our study also showed that ITS1 PCR-RFLP could identify Leishmania species from biopsy samples and suggests the method could be used for epidemiological surveillance of leishmaniasis in Ethiopia and for species-specific diagnosis.     

Multiple forms of alkaline phosphatase isoenzymes of Serratia marcescens

Alkaline phosphatase (APase) isoenzymes produced by different strains of Serratia marcescens were examined. Variation of isoenzyme patterns with respect to number and their mobilities in starch gels after electrophoresis were observed. Ten strains gave a 1-isoenzyme pattern with 5 different mobilities; 7 strains gave a 2-isoenzyme pattern with 3 different mobilities; 9 strains gave a 3-isoenzyme pattern with 5 different mobilities; and 3 strains gave a 4-isoenzyme pattern. Three strains synthesized two electrophoretically distinct APases in low phosphate medium. A high concentration of inorganic phosphate induced the synthesis of one of these APase isoenzymes.