Expression of the mutant gene for L-gulono-γ-lactone oxidase in scurvy-prone rats

A mutant strain of Wistar rats with L-gulono--lactone oxidase deficiency has recently been established. To investigate this deficiency by DNA and RNA blot hybridization analyses, a fragment of a previously cloned cDNA encoding rat L-gulono--lactone oxidase was used as a probe. When genomic DNA of the mutant rat was digested with several restriction enzymes, the probe hybridized to fragments of the same sizes as those produced from DNA of normal rats. Poly(A)⁺RNA from the liver of the mutant rat was found to contain an L-gulono--lactone oxidase-specific mRNA of a normal size at a comparable level to that of normal rats. An in vitro translation experiment revealed that the mRNA programmed the synthesis of an enzyme protein which had the same molecular weight as that of the translational product of the normal mRNA, although the amount synthesized was markedly reduced as compared with that synthesized with the normal mRNA. In accordance with this observation, a very low but definite degree of L-gulono--lactone oxidase activity was detected in the microsomes of the mutant rat by a newly developed, highly sensitive method.Acknowledgments. The authors thank Dr Susumu Makino, Shionogi Research Laboratories, Shionogi & Co., Ltd, Japan, for his kind donation of normal (ODS- +/+) and ODS (ODS-od/od) rats. This work was supported in part by Grant-in-Aid (59570103) for Scientific Research from the Ministry of Education, Science and Culture of Japan.     

药用甘薯组织培养中酶谱的变化初报

药用甘薯—西蒙1号的离体茎、叶及块根外植体,在含有不同配比的植物生长调节剂的MS培养基中可脱分化形成愈伤组织.改变植物生长调节剂的配比,可使其再分化形成根.如切取茎尖或带腋芽的茎段,则可直接形成小植株.西蒙1号茎、叶及块根脱分化形成的愈伤组织及再分化形成的根,其过氧化物酶及淀粉酶同工酶活性,以及谱带数均有所不同,这些变化与其分化状态有关.     

薏苡与几种主要玉米类型同工酶比较分析

通过对薏苡与５种主要类型的玉米酯酶、过氧化物酶、可溶性蛋白的比较发现：随发育进程提高，同工酶谱带更复杂；由过氧化物酶同工酶结果看出，薏苡与硬粒型玉米亲缘关系更接近，而通过酯酶、可溶性蛋白比较，不能看出薏苡与哪一种玉米类型亲缘关系更接近；玉米各类型间的同工酶也互不相同，各自有特异酶带。     

水稻乙醇酸氧化酶的纯化和特性分析

从水稻绿叶分离纯化得到一种单来基的乙醇酸氧化酶，其全酶分子量约为２６０ＫＤ，电泳特性表明该酶的ｐＩ〈８．３我们用改进的８％ＰＡＧＥ，结合Ｗｅｓｔｅｒｎ ｂｌｏｔ，测定水稻绍叶中还存在一种ｐＩ〉８．３的全酶Ｍｒ〉６６９ＫＤ的乙醇酸氧化酶。     

荔枝种子脱水敏感性与组织褐变的关系

荔枝种子在贮藏过程中对脱水高度敏感,随着种子含水量下降,种子的发芽率、活力指数和总酚含量下降;多酚氧化酶活性先上升然后迅速下降。其脱水敏感性的原因可能是荔枝种子膜的完整性受到损伤,酚类物质和多酚氧化酶的细胞内分室作用丧失,酚类被氧化成醌,从而毒害细胞,加速种子的劣变和死亡。     

激光照射对大豆幼苗生物学效应的初步研究

激光照射后的大豆幼苗的生长，叶和根的生长均有促进作用，照射次数赵多，照射时间越长，效应越强，激光照射后12天的大豆幼苗子叶，上胚轴，下胚轴和根的过氧化物同工酶谱均发生了变化，并讨论了激光对大豆幼苗的生物学效应。     

Respiratory burst in peritoneal exudate cells in response to a modified tuftsin

Intraperitoneal administration of tuftsin-M [Thr–Lys–Pro–Arg–NH–(CH₂)₂–NH–CO–C₁₅H₃₁] to Balb/C mice has been shown to induce a respiratory burst in the peritoneal exudate cells. The macrophages exhibited enhanced levels of O₂ ^–, H₂O₂, NADPH oxidase and myeloperoxidase, but the activities of superoxide dismutase, catalase and glutathione peroxidase remained virtually unchanged. The magnitude of the oxidative burst depended directly on the dose of tuftsin-M; higher activity was observed at higher doses of the peptide. Tuftsin-M enhanced the generation of both O ₂ ^– and H₂O₂ under in vitro conditions, as did phorbol myristate acetate. These results suggest that tuftsin-M could enhance non-specific defence against infections by activating the macrophages.     

懒猴和树的乳酸脱氢酶同工酶的研究

用聚丙烯酰胺凝胶园盘电泳和光电扫描仪对懒猴和树的心、肌、肝,肾、肠、脾、肺、血的乳酸脱氢酶同工酶进行了分析,结果表明,除懒猴肝脏仅显示3条酶带和树血液显示4条酶带以外,两种动物所有被测的其它器官组织均有5条酶带;不同种的同一器官组织,同一物种的不同器官组织,各酶带的相对百分含量绝大多数都显著不同.表现了种属特异性和组织特异性.同时,计算了血清乳酸脱氢酶同工酶A、B亚基的相对百分含量,并与人、猴、小白鼠已知血清参数进行了比较,发现A亚基的百分比值:小白鼠>树(>懒猴>猴>人,表明亚基的百分含量与动物的进化有关.     

薏苡(Coix.L)正常幼苗与白化苗的同工酶分析

比较薏苡正常幼苗与其白化苗的过氧化物酶及酯酶的同工酶的结果表明,正常绿苗的过氧化物酶酶带有8条,白化苗有10条(多出A_5、A_7);正常绿苗的酯酶同工酶带有4条,白化苗有3条,白化苗缺少B_2带,并且B_(1-1)与B_1带相近似。结果表明白化与过氧化物酶及酯酶同工酶的表达有关系。