Cleavage of territrems by alkaline hydrogen peroxide: Isolation and characterization of the aromatic moiety of territrems

The chemical reaction of cleavaging territrem B to give 3,4,5-trimethoxy benzoic acid by alkaline hydrogen peroxide was investigated. The method was applied for confirmation of the chemical structure of the aromatic moiety of territrem A, A’, B, and B’. The physicochemical properties of the aromatic cleavage product of territrem Aindicated the structure as 3,4-methylendioxy, 5-methoxy benzoic acid (or 4-methoxy, 6-carboxy, 1, 3-benzodioxole). The experiment also gave the evidences that territrem A and A’, on the other hand territrem B and B’ have the identical aromatic moieties on their structures.     

beta-Oxidation and Glyoxylate Cycle Coupled to NADH: Cytochrome c and Ferricyanide Reductases in Glyoxysomes

Glyoxysomes isolated from castor bean (Ricinus communis L., var Hale) endosperm had NADH:ferricyanide reductase and NADH:cytochrome c reductase activities averaging 720 and 140 nanomole electrons/per minute per milligram glyoxysomal protein, respectively. These redox activities were greater than could be attributed to contamination of the glyoxysomal fractions in which 1.4% of the protein was mitochondrial and 5% endoplasmic reticulum. The NADH:ferricyanide reductase activity in the glyoxysomes was greater than the palmitoyl-coenzyme A (CoA) oxidation activity which generated NADH at a rate of 340 nanomole electrons per minute per milligram glyoxysomal protein. Palmitoyl-CoA oxidation could be coupled to ferricyanide or cytochrome c reduction. Complete oxidation of palmitoyl-CoA, yielding 14 nanomole electrons/per nanomole palmitoyl-CoA, was demonstrated with the acceptors, NAL, cytochrome c, and ferricyanide. Malate was also oxidized by glyoxysomes, if acetyl-CoA, ferricyanide, or cytochrome c was present. Glyoxysomal NADH:ferricyanide reductase activity has the capacity to support the combined rates of NADH generation by β-oxidation and the glyoxylate cycle.     

The effect of light and phytochrome on 1-aminocyclopropane-1-carboxylic Acid metabolism in etiolated wheat seedling leaves

While light-grown wheat leaves produced ethylene at a low rate of <0.1 nanomoles per gram per hour and contained 1-aminocyclopropane-1-carboxylic acid (ACC) at low levels of <2.5 nanomoles per gram, etiolated wheat leaves produced ethylene at a rate of 2 nanomoles per gram per hour and accumulated concentrations of ACC at levels of 40 nanomoles per gram. Upon illumination of 8-day-old etiolated wheat seedlings with white light, the ethylene production rate increased initially, due to the activation of ethylene-forming activity, but subsequently declined to a low level (0.1 nanomoles per gram per hour) at the end of the 6-hour illumination. This light-induced decline in ethylene production rate resulted from a decline (more than 35 nanomoles per gram) in ACC level, which was accompanied by a corresponding increase in 1-(malonylamino)cyclopropane-1-carboxylic acid content. These data indicate that illumination promoted ACC malonylation, resulting in reduced ACC level and consequently reduced ethylene production. However, light did not cause any significant increase in the extractable ACC-malonyltransferase activity. The effect of continuous white light on promotion of ACC malonylation was also observed in intermittent white light or red light. A far-red light treatment following red light partially reversed the red light effect, indicating that phytochrome participates in the promotion of ACC malonylation.     

心不甘中甾体皂甙元的分离和结构鉴定(2)

自心不甘(Tupistra aurantiaca Wall et Backer)根的醋酸乙酯萃取物经硅胶柱层析分离除可得到1β、2β、3β、4β、5β、7α-hexahydroxyspirost-25(27)-en-6-one外,还得到7个游离的甾体皂甙元A—G,其中A及B分别为3-epiruscogenin及3-epi-neoruscogenin,F为△~(25(27))-pentrogenin(6)、C、D和E系新化合物,经IR、MS、~1H NMR及~(13)C NMR谱鉴定分别推定为ranmogenin A(3)、B(4)和C(5)(兰茂甙元甲、乙和丙)。     

心不甘中甾体皂甙元的分离和结构鉴定(3)

本文报告心不甘(Tupistra aurantiaca Wall et Backer)根的粗甙经盐酸水解后的总甙元中分离的甙元E和F的结构鉴定。甙元F经鉴定为△~(25(27))-pentrogenin(2)。甙元E(ranmo-genin D)为新化合物,其结构经IR、MS、~1H NMR和~(13)C NMR谱分析推定如(1)所示。     

大鼠发育过程中肝、肺r-GT酶活性和定位

用生物化学和组织化学方法研究正常发育中大鼠肝、肺r-GT活性和定位。结果表明:肝r-GT活性自胚龄17天开始升高,21天达高峰,出生第一天明显降低,第六天降至接近成年低水平。在胚胎期肝r-GT主要位于肝细胞内,出生后则主要位于胆小管。该结果提示胚胎期肝r-GT主要参与肝细胞膜上氨基酸的转运。出生后可能主要参与解毒功能,大鼠肺r-GT活性随发育逐步升高,主要分布于肺支气管上皮细胞。提示肺r-GT可能参与解毒功能。     

Identification of cellular mechanisms operational in vivo during the regression of established pulmonary metastases by the systemic administration of high-dose recombinant interleukin 2

The systemic administration of high-dose recombinant IL 2 mediated significant reductions of established 3-day pulmonary micrometastases from both weakly immunogenic and nonimmunogenic sarcomas. However, when treatment with IL 2 was delayed for 10 days after the injection of tumor cells in an attempt to treat grossly visible pulmonary macrometastases, only those established from weakly immunogenic sarcomas remained susceptible. Established 10-day pulmonary nodules from the nonimmunogenic sarcomas became refractory to IL 2 therapy. We utilized selective depletion of lymphocyte subsets in vivo by the systemic administration of specific monoclonal antibodies to cells bearing either the L3T4 or Lyt-2 marker or a heteroantiserum to cells bearing the ASGM-1 glycosphingolipid to identify lymphocytes involved in IL 2-induced tumor regression. Cells with potent lymphokine-activated killer (LAK) activity against fresh tumor targets in vitro were identified in the lungs of IL 2-treated mice. By flow cytometry analysis, the majority of these effector cells were Thy-1+, L3T4-, Lyt-2-, ASGM-1+. Depletion in vivo of ASGM-1+ cells before the onset of IL 2 administration eliminated the successful therapy of 3-day pulmonary metastases from nonimmunogenic sarcomas, with concurrent elimination of LAK cell activity in the lungs. In mice with 3-day pulmonary metastases from weakly immunogenic sarcomas, both Lyt-2+ cells and ASGM-1+ cells were involved in IL 2-mediated tumor regression, but Lyt-2+ cells appeared to be the more potent mediator in the response. Lyt-2+ cells were also involved in the elimination of grossly visible 10-day macrometastases from these weakly immunogenic tumors. Depletion of L3T4+ cells had no effect on tumor regression. Thus, although LAK effectors derived from ASGM-1+ precursors can eliminate pulmonary micrometastases regardless of tumor immunogenicity, Lyt-2+ cells are predominant effectors in the elimination of both pulmonary micro- and macrometastases from weakly immunogenic sarcomas.     

Formation of lymphocyte colonies under serum-free culture conditions in normal individuals and patients with chronic lymphocytic leukemia

This paper describes a culture system which supports the formation of B cell and some T cell colonies under serum-free conditions in peripheral blood samples of normal individuals and patients with chronic lymphocytic leukemia (CLL) of B cell type. In this system, serum is replaced by bovine serum albumin, transferrin, cholesterol, insulin and catalase or horseradish peroxidase. In addition, it is necessary to add staphylococcus protein A, mitomycin-treated T cells as feeders and phytohemagglutinin leukocyte-conditioned medium as a source of growth factors. The plating efficiency is greatly enhanced when normal cells are incubated with galactose oxidase prior to plating and when CLL cells are exposed sequentially to neuraminidase and galactose oxidase.     

Size and composition of lymph chylomicrons following feeding corn oil or its fatty acid methyl esters

Male rats with thoracic duct cannulae were intubated with corn oil or fatty acid methyl esters and the lymph was collected over the next 2-72 h. The apoprotein (apo) composition of the chylomicrons, isolated by conventional ultracentrifugation, was determined by sodium dodecyl sulfate - polyacrylamide - glycerol gel electrophoresis and isoelectric focusing. The lipid content and composition was assessed by gas--liquid chromatography. The particle size was obtained by calculation and confirmed by electron microscopy. The study demonstrates that both the monoacylglycerol (corn oil feeding) and the phosphatidic acid (methyl ester feeding) pathways of triacylglycerol biosynthesis yield chylomicrons with closely similar apoprotein profiles representing apo B-48, apo A-IV, apo E, apo A-I, and the apo C components. A protein band corresponding to apo B-100 was occasionally observed as a minor component of the chylomicrons from both groups of animals. The chylomicrons from corn oil feeding had about two times larger diameters than those from methyl ester feeding. There were no significant differences in the composition of the apoproteins, although the smaller particles had two times higher apoprotein/triacylglycerol ratios. It was calculated that the amount of apo B per lipid particle for the ester fed rats ranged from one to eight molecules and was closely correlated with the particle size. The corn oil fed rats yielded about three molecules apo B per lipid particle regardless of the particle size. It is concluded that the pathway of intestinal triacylglycerol biosynthesis has a significant effect on the apoprotein mass and to a lesser extent on the apoprotein and lipid composition of the chylomicrons. The phosphatidic acid pathway produces smaller particles and transfers to the bloodstream twice as much apoprotein per gram of fat than the monoacylglycerol pathway, which yields the larger particles. Possible variations in the site and rate of biosynthesis of the triacylglycerols could not be entirely excluded as contributing factors.     

Stereochemical course of intestinal absorption and transport of mustard-seed oil triacylglycerols in the rat

Male rats with thoracic duct cannulae were intubated with mustard-seed oil or the corresponding fatty acid methyl esters and the lymph was collected over 0-24 h. The chylomicron and very low density lipoprotein fractions were obtained by conventional ultracentrifugation. The triacylglycerols and glycerophospholipids were isolated and the positional distribution and molecular association of fatty acids were determined by stereospecific and chromatographic methods. The oleic, linoleic, and linolenic acids were recovered in the lymph in the proportion in which they occurred in the fat fed, while eicosenoic, erucic, and lignoceric acids were rejected to about the same extent by the two pathways of intestinal triacylglycerol biosynthesis. It is shown that the lymph triacylglycerols arising via the monoacylglycerol or the phosphatidic acid pathway possess structures that are closely similar to each other and to that of the original mustard-seed oil. It is proposed that this is a result of comparable fatty acid and positional specificity of the acyltransferases associated with the acylglycerol synthesis in the animal and plant tissues and the wide range of fatty acid chain lengths in the mustard-seed oil.