Production and characterization of antibody against aflatoxin Q1.

Antibodies against aflatoxin Q1 (AFQ1) were obtained from rabbits after immunization of either AFQ1-hemisuccinate or AFQ2a conjugated to bovine serum albumin. Both radioimmunoassay and enzyme-linked immunosorbent assaY (ELISA) were used for the determination of antibody titers and specificities. Antibodies obtained from rabbits after immunization with AFQ1-hemisuccinate-bovine serum albumin had the highest affinity to aflatoxin B1, whereas antibodies obtained from rabbits after immunization with AFQ2a-bovine serum albumin bound most effectively with AFQ2a. AFQ2a antibody was selected for the subsequent direct and indirect ELISA for the detection of AFQ1 in biological fluids. When AFQ2a-peroxidase and AFQ2a antibody were used, direct ELISA was able to detect as low as 2 ppb (ng/ml) of AFQ1 spiked in the urine samples that had been subjected to a Sep-Pak cleanup treatment. In indirect ELISA in which the antigen (AFQ2a-bovine serum albumin) was coated to the solid phase followed by reaction with rabbit antibody and goat anti-rabbit immunoglobulin G-peroxidase conjugate, 50-fold less antibody was used without sacrificing sensitivity. Recoveries of AFQ1 added to urine samples (2 to 40 ppb) were 46.3 to 73% and 65.8 to 85.8% for direct and indirect ELISA, respectively.     

Glyoxylate transamination in intact leaf peroxisomes

Intact spinach (Spinacia oleracea L.) leaf peroxisomes were supplied with glycolate and one to three of the amino acids serine, glutamate, and alanine, and the amount of the respective α-keto acids formed in glyoxylate transamination was assayed. At 1 millimolar glycolate and 1 millimolar each of the three amino acids in combination, the transamination reaction reached saturation; reduction of either glycolate or amino acid concentration decreased the activity. The relative serine, glutamate, and alanine transamination at equal amino acid concentrations was roughly 40, 30, and 30%, respectively. The three amino acids exhibited mutual inhibition to one another in transamination due to the competition for the supply of glyoxylate. In addition to this competition for glyoxylate, competitive inhibition at the active site of enzymes occurred between glutamate and alanine, but not between serine and glutamate or alanine. Alteration of the relative concentrations of the three amino acids changed their relative transamination. Similar work was performed with intact oat (Avena sativa L.) leaf peroxisomes. At 1 millimolar of each of the three amino acids in combination, the relative serine, glutamate, and alanine transamination was roughly 60, 23, and 17%, respectively. Similarly, alteration of the relative concentration of the three amino acids changed their relative transamination. The contents of the three amino acids in leaf extracts were analyzed, and the relative contribution of the three amino acids in glycine production in photorespiration was assessed and discussed.     

Phytophthora spp. from rubbertree plantations in Yunnan Province of China

Phytophthora spp. associated with leaf fall, stem canker and black stripe of rubbertree (Hevea brasiliensis Muell.-Arg.) in Xishuangbanna of Yunnan Province were isolated from leaves, bark, fruit and soil in the plantations. Of a total of 50 isolates, 42 were designated as P. citrophthora (R. E. Sm. & E. H. Sm.) Leonian, while the others were identified as P. palmivora (Butl.) Butl., P. colocasiae Rac. and P. cactorum (Leb. & Conn) Schroet. This appears to be the first report of P. citrophthora on Hevea brasiliensis.     

PI LBEI and PI JHOU: two new alpha-1-antitrypsin alleles

Summary Two new variants of alpha-1-antitrypsin were found in a Chinese population by isoelectric focusing in polyacrylamide gel. They have been named Lbeijing (PI^*LBEI) and Jhouyao (PI^*JHOU) respectively. With the samples reduced and alkylated, both the variants were anodal to M1 and cathodal to L. Omitting the alkylation step, however, the relative mobilities of L and Jhouyao were altered. Under this condition, a characteristic of Jhouyao was revealed by isoelectric focusing in immobilized pH gradient 4.4–4.9, i.e., while its band 6 became anodal to L, band 4 was still cathodal to L.     

中国蚜科新纪录,4

在调查云南森林昆虫中发现下述种类为我国首次纪录。 大尾小长管蚜Macrosiphoniella grandicauda Takahashi et Kuwana, 1963,中国新纪录。采自云南丽江(林科所1980.V.23),各型孤雌蚜。寄主为艾蒿,盖满3—4寸嫩梢。活体叶绿色,体稍扁。不易从植物上坠落。国外分布于朝鲜、日本和印度。     

鄂东南早白垩世灵乡群孢粉组合

本文根据从大冶灵乡-陈重山剖面的中部、灵乡狮子山东侧采坑和鄂城太和1孔的相当层位中所获得的孢粉组合(共67属120余种,其中新种9个,新联合2个),认为灵乡群孢粉组合属于 Classopollis、Psophosphaera-Cicatricosisporites、Schizaeoisporites-没有或极个别的出现被子植物花粉的组合类型,其地质时代应为早白垩世早期-中期(凡兰吟期-巴列姆期)。并推测鄂东南地区当时的气候属于偏干旱的热带-亚热带型。     

新型有原始肢突胴甲鱼的发现及胴甲鱼早期演化的初步探讨

本文记述的曲靖始突鱼(Procondylolepis qujingensis gen.et sp.nov.)是近几年在云南曲靖早泥盆世地层中发现的有肢突胴甲鱼一原始类型。它和已知胴甲鱼(包括早泥盆世无肢突的和中、晚泥盆世有“盔”状肢突的)不同的最大特点是在其肩带与胸鳍相接的肩关节处有原始的肢突和简单的关节窝;胸鳍甲近端的关节区很小。它展现出胴甲鱼类这一高度特化、长期使人迷惑不解的肢突,在胴甲鱼演化史上发展变化的梗概,填补了肢突从无到有中间的缺环,使人了解到胸鳍的具体结构。文中主要根据肢突的有无和特化程度等,对胴甲鱼早期演化史作了初步探讨,将胴甲鱼分为无肢突超目(Abrachicondylia)和有肢突超目(Brachicondylia)两大部分。始突鱼则代表有肢突超目一早期成员。     

Murine leukemia cell hybrids: The quantity of TL antigens expressed by parental and hybrid cells fails to correlate with their sensitivity to TL antibody and complement

The quantity of thymus-leukemia (TL) antigens expressed by murine leukemia cells is significantly greater than that expressed by somatic hybrids of such cells. Based upon the results of ¹²⁵I-lactoperoxidase labeling and antibody absorption procedures, and corrected for size differences between the two cell types, the quantity of TL antigens expressed by RADA-1 cells, a radiation-induced murine leukemia cell line of strain A/J mice, is approximately 5.0 times greater than that of somatic hybrids of RADA-1 and LM(TK)^? cells. LM(TK)^? cells are a thymidine kinase-deficient TL(-) mouse fibroblast cell line. The quantity of TL antigens expressed is related only in part to their susceptibility to lysis by TL antibodies and guinea pig complement (GPC). RADA-1 cells resist lysis. The quantity of TL antigens expressed by RADA-1 cells is analogous to that formed by nonneoplastic thymocytes obtained from F₁ hybrids of two strains of TL(+) and TL(-) mice; cells from both strains are sensitive to TL antiserum and GPC. ASL-1 cells, a spontaneously occurring leukemia cell line of A/J mice, express TL antigens in significantly higher quantities than any of the cell types examined. Exposed to TL antisera, the quantity of TL antigens of ASL-1 cells, but not that of hybrid cells, gradually diminishes. ASL-1 cells convert over a 6-h period of exposure to antibody and guinea pig complement (GPC) resistance; hybrid cells remain sensitive. However, ASL-1 cells converted to TL antibody and GPC resistance continue for a time to express TL antigens in quantities similar to that of sensitive F₁ thymocytes and resistant RADA-1 cells. RADA-1 X LM(TK)^? hybrid cells, which are sensitive to TL antibodies and GPC, express the lowest quantities of TL antigens of any of the cell types examined. It is likely that differences in the quantities of TL antigens expressed by different cell lines reflect genetic mechanisms controlling TL antigen expression. The failure of TL antisera to affect the quantities of TL antigens expressed by hybrid cells is taken as an indication that genetic controls governing antigen expression may be distinguished from those involved in regulating responsiveness to specific antiserum.     

应用植物学的研究动向

在一九八一年八月二十一日至二十九日于澳大利亚悉尼召开的“第十三届国际植物学会议”上,应用植物学作为一个学科组共有下列十三项中心议题:1.植物生产力的改进——生理学界线的探讨;2.植物育种的新领域;3.在植物生物学中的细胞培养和体细胞遗传;4.杂草的性质及其起源;5.有利于人类幸福的民族植物学;6.改善旱地作物的水分利用;7.生态系统中的氮素迁移;8.树木营养;9.人工气候室