Enhancement of CO2 tolerance of Chlorella vulgaris by gradual increase of CO2 concentration

Summary Chlorella vulgaris UTEX259 was cultivated using two different methods of gas supply. In one method the CO₂ concentration in bubbled gas was held constant and in the other method it was increased gradually. Algal growth was almost linear after a short period of lag phase in both methods. With the constant CO₂ concentration, the CO₂ fixation rate in the linear growth phase decreased over 10%(v/v) CO₂, while the rate increased up to 6% CO₂. However, the rate was enhanced by using the latter incremental increase method, especially under a higher concentration of CO₂. The maximum rate of CO₂ fixation was 52 mg CO₂/l·h at 20% CO₂ during the gradual increase of CO₂ concentration.     

萌发花生种子子叶肽链内切酶的纯化和性质

萌发花生种子子叶的肽链内切酶经硫酸铵沉淀,ＳｅｐｈａｄｅｘＧ－１００凝胶层析,ＤＥＡＥ－纤维素２３阴离子交换层析和ＤＥＡＥ－ＳｅｐｈａｄｅｘＡ５０层析,得到纯化的酶,该酶有两条同工酶,分子量分别为５８和５５ＫＤ,Ｋｍ为９．９μｍｏｌ／Ｌ,是半胱氨型肽链内切酶（ＥＣ３．４．２２）,对未萌发花生种子的贮藏蛋白没有明显降解作用．     

海南坡鹿对生境的选择

１９８７～１９９４年,在海南省大田自然保护区及其外围地带对坡鹿的生境选择性进行了调查,发现坡鹿对自然生境有较强的选择性。对不同的生境的选择频率为：落叶季雨林生境４７．９３％;灌木草地生境３９．１４％;有刺灌丛生境１０．７２％;人工林生境２．２１％。还对各种生境进行了评价;并提出了保护生境的对策     

Prostaglandin H Synthetase-Mediated Metabolism of Dopamine: Implication for Parkinson's Disease

Abstract: Differences in prostaglandin H synthetase (PHS) activity in the substantia nigra of age- and post-mortem interval-matched parkinsonian, Alzheimer's, and normal control brain tissue were assessed. Prostaglandin E₂ (PGE₂, an index of PHS activity) was higher in substantia nigra of parkinsonian brain tissue than Alzheimer's or control tissue. Incubation of substantia nigra slices with arachidonic acid (AA) increased PGE₂ synthesis. Dopamine stimulated PHS synthesis of PGE₂. [³H]Dopamine was activated by PHS to electrophilic intermediate(s) that covalently bound to DNA, microtubulin protein, bovine serum albumin, and sulfhydryl reagents. When AA was replaced by hydrogen peroxide, PHS/H₂O₂-supported binding proceeded at rates similar to those observed with PHS/AA. Indomethacin and aspirin inhibited AA-mediated cooxidation of dopamine but not H₂O₂-mediated metabolism. PHS-mediated metabolism of dopamine was not affected by monoamine oxidase inhibitors. Substrate requirements and effects of specific inhibitors suggest cooxidation of dopamine is mediated by the hydroperoxidase activity of PHS. ³²P-postlabeling was used to detect dopamine-DNA adducts. PHS/AA activation of dopamine in the presence of DNA resulted in the formation of five dopamine-DNA adducts, i.e., 23, 43, 114, 70, and 270 amol/µg DNA. DNA adduct formation was PHS, AA, and dopamine dependent. PHS catalyzed cooxidation of dopamine in dopaminergic neuronal degeneration is discussed.     

高必需氨基酸转基因马铃薯的研究

８０年代以来,马铃薯遗传转化系统日趋成熟,转基因工程植株已被广泛应用于基础科学研究［１］。作为食物蛋白和能量主要来源的马铃薯,提高其蛋白质含量及质量的遗传工程研究正受到人们的普遍关注［２］。Ｙａｎｇ等［２］将旨在改善氨基酸平衡的ＣＡＴ－ＨＥＡＡＥ（氯酶素乙酰转移酶－高含量人体必需氨基酸）融合基因导入马铃薯,获得了Ｓｏｕｔｈｅｒｎｂｌｏｔ、Ｎｏｒｔｈｅｒｎｂｌｏｔ、Ｗｅｓｔｅｒｎｂｌｏｔ的证据,但尚缺少氨基酸分析的资料。玉米醇溶蛋白（ｚｅｉｎ）［３］是一个富含甲硫氨酸的贮存蛋白,它和人工合成的ＨＥ…     

Mechanism for the increase in plasma renin activity by pentobarbital anesthesia

The mechanism by which pentobarbital anesthesia causes increases in plasma renin activity (PRA) was examined in dogs infused with either propranolol or indomethacin, an inhibitor of prostaglandin synthetase. Infusion of propranolol at 1 mg/kg, (I.V.) followed by 0.6–0.7 mg/kg/hr decreased PRA from 6.98±2.49 ng/m1/hr during control periods to 1.58±0.79 ng/m1/hr 30 minutes after the injection of propranolol (P<0.025). Subsequent induction of anesthesia with sodium pentobarbital caused PRA to rise to 3.87±0.93 ng/m1/hr in 30 minutes. (P<0.01). Plasma potassium concentration decreased from 4.6±0.2 mEq/L to reach 4.0±0.1 mEq/L 30 minutes after induction of anesthesia (P<0.005). Infusion of indomethacin at 5 mg/kg, (I.V.) followed by 1.5 ? 3.1 mg/kg/hr into conscious dogs did not decrease PRA. In contrast to the report by Montgomery et al (Fed. Proc. 36: 989, 1977), we found that the increase in PRA after pentobarbital anesthesia could not be blocked by indomethacin. PRA was 5.3±1.2 ng/m1/hr(M ± SEM) during control periods and was 4.7±1.4 ng/m1/hr 30 minutes after the infusion of indomethacin (P<0.1). PRA increased to 10.9±2.3 ng/m1/hr, 9.2±2.2 ng/m1/hr, and 7.7±1.7 ng/m1/hr at 5, 15 and 30 minutes, respectively, after the administration of pentobarbital (P<0.005, P<0.025, P<0.05). PRA declined to 4.2±1.3 ng/m1/hr 60 minutes after pentobarbital anesthesia (P<0.1). It is concluded that the mechanism by which pentobarbital causes increases in PRA is independent of prostaglandins.     

线性规划法在植物生态学数学模型参数估计中的应用初探

本文提出了一种植物生态学数学模型参数估计的新方法——线性规划法,并结合最小二乘法对模型参数的估计进行了实例分析。认为某种程度上前者更优于后者。是一种值得进一步研究的方法。     

Karyotypes of Pneumocystis carinii from Korean rats.

Molecular karyotyping was applied to Pneumocystis carinii(Pc) from two strains of experimental rats, Sprague Dawley(SD) and Fisher(F), in Korea. Field inversion gel electrophoresis and contour clamped homogeneous electric field electrophoresis resolved 15 chromosomal bands from the Pc. The size of the bands was estimated 270kb to 684kb from SD rats, and 273kb to 713 kb from F rats. The bands of 283 kb from SD rats and of 273 kb from F rats stained more brightly suggesting duplicated bands. Total number of chromosomes was at least 16, and total genomic size was estimated 7 x 10(6) bp. All of the bands from F rats hybridized to the probe of repeated DNA sequences of Pc and the band of 448 kb size was proved to contain rDNA sequences, but Pc. chromosome bands from SD rats showed no reactions to the probes. The 2 different karyotypes of P. carinii from 2 strains of rats were maintained consistently for 2 years.     

Expression of glucoamylase gene usingSUC2 promoter inSaccharomyces cerevisiae

Summary The cloning of glucoamylase geneSTA using theSUC2 promoter intoSaccharomyces cerevisiae was performed. The signal sequence ofSTA gene was used for the secretion of glucoamylase protein. The plasmid constructed in this way was named YEpSUCSTA and its expression was identified. The expression of YEpSUCSTA was repressed in the presence of glucose in growth medium, but derepressed when glucose became depleted. YEpSUCSTA showed the similar efficiency of glucoamylase secretion as YEpSTA-F which has the entireSTA gene. Glucoamylase activity in starch-glucose medium was largely increased because cell mass and plasmid stability were high in biosynthesis phase compared to extracellular glucoamylase activities in media which starch or glucose was the only carbon source.