斯氏并殖吸虫乳酸脱氢酶,苹果酸脱氢酶及酯酶同工酶的研究

本文采用Disc-PAGE电泳,首次对我国独有的斯氏并殖吸虫(Paragonimus skrjabini Chen,1959)成虫、童虫、囊蚴的乳酸脱氢酶(以下简称LDH)、苹果酸脱氢酶(以下简称MDH)和酯酶(以下简称EST)同工酶进行了研究。 在成虫、童虫、囊蚴间,LDH、MDH、EST同工酶在酶带数、排列型式、Rf值、相对活性和优势酶带的位置都存在差异。 根据虫体和宿主组织同工酶谱的不同,可以认为是本虫本身所具有。 同工酶作为其分类指标时,不仅要比较不同虫种成虫稳定的同工酶谱,也要比较同工酶在个体发育型式间的差异。     

人型结核杆菌全染色体DNA探针鉴别结核杆菌和其安分枝杆菌

The dot-blots containing DNA isolated from nonmycobacterial and mycobacterial microorganisms were hybridized with 32P-labeled M. tuberculosis whole chromosomal DNA at the various temperatures. The probe did not cross-hybridize to DNA of nonmycobacterial microorganisms (E. coli, Plasmid pUC19, Nocardia asteriodes), nor with DNA from all mycobacteria tested except M. bovis BCG under the higher temperature conditions. Microorganisms could also be directly spotted and lysed on nitrocellulose filters and used for hybridization thus making this technique suitable for clinical diagnosis.     

The genetic defect in multiple endocrine neoplasia type 2A maps next to the centromere of chromosome 10

Multiple endocrine neoplasia type 2A (MEN2A) is a rare cancer syndrome that is inherited in an apparently autosomal dominant fashion. Previous linkage studies had assigned the MEN2A locus to chromosome 10 in the pericentromeric region. We recently have described several new easily scorable RFLPs for the chromosome 10-specific alpha satellite DNA (the D10Z1) locus that is known, on the basis of previous in situ hybridization experiments, to lie at the centromere. We report here tight linkage between MEN2A and D10Z1, as demonstrated by a maximum lod score of 12.02 at the recombination frequency of zero (1-lod-unit support interval 0-4 cM), indicating that the genetic defect in MEN2A lies in the immediate vicinity of the centromere. By means of a set of ordered polymorphic DNA markers from the pericentromeric region, multipoint as well as pairwise linkage analyses place the MEN2A locus at the middle of a small region (approximately 11 cM) bracketing the centromere with FNRB (at 10p11.2) and RBP3 (at 10q11.2) on either side, providing further support for the centromeric location of the MEN2A locus. Marked sex difference in recombination frequencies exists in this pericentromeric region: significantly (P less than .01) more female than male crossovers were observed across all of the adjacent intervals D10S24-FNRB, FNRB-D10Z1, and D10Z1-RBP3. However, a sex difference was not seen in the 7-cM interval from RBP3 to D10S5, suggesting that large variation in the sex difference in recombination can occur over small chromosomal regions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Microbial transformations of 7,2-dimethylbenz[a]anthracene.

Microbial transformations of 7,12-dimethylbenz[a]anthracene, a carcinogenic polycyclic aromatic hydrocarbon, in cultures of Pseudomonas aeruginosa and Penicillium notatum were studied by high performance liquid chromatographic separation of metabolic fractions followed by gas chromatographic-mass spectrometric analysis of the metabolites. Two methyl-hydroxylated metabolites were identified in each of the incubations. The metabolic activation of the polycyclic aromatic hydrocarbon suggests a possible involvement of microorganisms in environmental carcinogenesis.     

高寒草甸土壤昆虫的数量与生物量及其影响因素

昆虫数量变动包括“数”和“量”两方面,“数”即密度,人们早已惯用;“量”即生物量和能量,尚很少应用。因为相同数目的个体不一定具有相同的生物量或能量,所以从群落的食物链索关系或生态系统的能量流来看,单纯的个体数不足以表示所起的作用。因此,如何从“数”的概念过渡到“量”的概念,从更切实的基础上了解这种动态的实质是非常重要的。本文仅就土壤昆虫的数量与生物量作一初步探讨,以便结合其它有关研究最终阐明草甸生态系统的结构和功能,从而把草甸的生产和管理建立在合理的基础之上。     

温度对干旱、盐胁迫下两种黄芪属种子萌发和幼苗生长的影响

为探讨温度对干旱、盐胁迫下黄芪属种子萌发和幼苗生长特性的影响,以黄芪属蒙古黄芪和扁茎黄芪2种种子为研究对象,纯净水处理为对照组,NaCl、PEG处理为实验组,设置4个渗透势水平(0、-0.1、-0.3、-0.5 MPa),置于5种不同的温度(10、15、20、25、30 ℃)下,每日观察并记录两种种子萌发和幼苗生长情况。结果表明：旱盐胁迫下蒙古黄芪和扁茎黄芪种子萌发最适宜的温度分别为25和20 ℃左右;蒙古黄芪耐高温不耐低温,而扁茎黄芪恰恰相反;但25和20 ℃均适宜两种幼苗生长,包括胚根、胚轴和子叶的生长。蒙古黄芪各处理组(除未发芽的种子)的平均发芽时间都比扁茎黄芪长;NaCl胁迫程度的增加使得两种种子的最终发芽率降低,但蒙古黄芪的耐盐性高于扁茎黄芪;随着PEG胁迫程度的增加,二者的发芽均受到抑制,甚至会出现完全不萌发,但扁茎黄芪的耐旱性高于蒙古黄芪;在相同的渗透势时,尤其是-0.5 MPa,PEG比NaCl对两种种子的影响大;交互胁迫作用下,随着渗透势的增加两种幼苗的鲜重、干重以及胚根、胚轴、子叶的长和宽变化较大;利用Design Expert软件预测发现：温度25 ℃、NaCl渗透势为-0.1 MPa,温度24 ℃、PEG渗透势为-0.04 MPa的处理是蒙古黄芪种子萌发和幼苗生长达到最优化的组合;而扁茎黄芪最优化的组合则为23 ℃下NaCl渗透势为-0.07 MPa的处理,20 ℃下PEG渗透势为-0.13 MPa的处理。     

草原生态学研究方法学术讨论会在成都召开

中国植物学会于1981年11月21日至27日在四川省成都市召开了有61名代表参加的草原生态学研究方法学术讨论会。大会收到包括植物群落结构调查研究、第一性生产力测定、第二性生产力测定、光合作用测定、物质与水分循环、热值测定、数学生态等有关内容的研究方法论文和报告34篇。其中有18篇论文在大会上作了报告。在小组讨论中,代表们就第一性生产力测定、水分与物质循环、光合作用测定     

Sensitivity of cultured pancreatic carcinoma cells toAcinetobacter glutaminase-asparaginase

Summary Cultured human pancreatic carcinoma cells (MIA PaCa-2) have been shown previously to be very sensitive toE. coli l-asparaginase (EC II). The present studies have demonstrated that another enzyme,Acinetobacter glutaminase-asparaginase (AGA) is much more effective in inhibiting cell growth. At the concentration of 0.0025 U/ml of AGA activity the enzyme totally inhibited cell growth, whereas the EC II with the same concentration did not show any effect. The inhibition of cell growth correlated well with inhibition of protein and glycoprotein synthesis. The addition ofl-glutamine at the concentration of 1 mM completely reversed the inhibition of protein synthesis. Similarly, the addition ofl-glutamine at the concentration of 3 mM daily on 3 successive days after adding AGA resulted in significant reversal of growth inhibition. The results of this study indicate that the action of AGA on MIA PaCa-2 is, to a great extent, exerted through itsl-glutaminase activity. This work was supported in part by USPHS Grant CA 19182. Dr. Wu is recipient of Research Career Development Award Grant CA00686 and Dr. Yunis is a Howard Hughes Investigator.     

Induced release and metabolism of arachidonic acid from myeloid cells by purified colony-stimulating factor

The in vitro incubation of cells from turpentine-induced rat myeloid hyperplastic marrow and peritoneal monocyte/macrophage with 14C-arachidonic acid resulted in the incorporation of the radiolabel into the particulate phospholipids. Challenge of the radiolabeled cells with a highly purified type I CSF (CSF I) from human pancreatic carcinoma cells in continuous culture resulted in the hydrolysis and release of the 14C-arachidonic acid from the cellular phospholipids. The simultaneous challenge of the prelabeled cells with CSF-I and its specific antibody (anti-CSF-I antibody) inhibited the CSF-I induced hydrolysis of 14C-arachidonic acid from the cells. These results confer a specificity on the CSF-I induced release of arachidonic acid from the cellular phospholipids. Our data also demonstrated that the 14C-arachidonic acid released from the cellular phospholipids was further transformed into products of the cyclooxygenation and lipoxygenation pathways by cellular enzyme systems in both populations of cells. Interestingly, our data also indicate that the challenge of the granulocytic hyperplastic marrow cells and the monocyte/macrophage cells with purified CSF-I resulted in a higher generation of lipoxygenase products in the predominantly granulocytic cell population than in the population rich in monocyte/macrophage cells. The biological significance of this observation remains to be further explored. Thus, the CSF-I induced release of cellular arachidonic acid explains, at least in part, the presence of prostaglandins and other metabolites of arachidonic acid that are found in the media of hemopoietic cells incubated with a variety of CSF preparations.     

Induction of mitotic gene conversion by browning reaction products and its modulation by naturally occurring agents

Mitotic gene conversion in the D7 strain of Saccharomyces cerevisiae was significantly enhanced by exposure to non-enzymatic browning reaction products. These products were formed during the heating of sugar (caramelization reaction) or sugar-amino acid mixtures (Maillard reaction) at temperatures normally used during the cooking of food. Several modulating factors of this convertogenic activity were identified. These factors included two main groups: (1) trace metals which are widely distributed in the environment; and (2) several cellular enzymatic systems. The convertogenic activities of a heated glucose-lysine mixture and a commercial caramel powder were completely suppresses when yeast were concurrently exposed to these products and to either FeIII or CuII. Equimolar concentrations of MnII or sodium selenite had no effect on the convertogenic activity of the products of either model system. Horse-radish peroxidase, beef liver catalase and rat liver S9 preparations each decreased the frequency of gene conversion induced by the caramel powder and the heated glucose-lysine products. This modulating activity of the enzymes was lost if they were heat-inactivated. These studies indicate the presence of a variety of protective mechanisms which can modify genotoxic components in complex food mixtures.