康定虫草主要寄主斜脉蝠蛾的研究

冬虫夏草是一味名贵的中药材.四川康定虫草的主要寄主斜脉蝠蛾翅面色斑多变异,可区分成“黑白斑”和“黄毛斑”两大色斑型.经交配试验和成虫形态特征(触角、口器、翅脉、前足、雌雄外生殖器和鳞片的超微结构等)的观察,证明为同一种,经鉴定是斜脉蝠蛾(Hepialus oblifurcus Chu et Wang)^**.     

柴达木盆地荒漠土壤蓝藻群落的初步研究

本文分析了柴达木盆地东部和中部具有代表性地区的丘陵、戈壁和沙丘的蓝藻种类组成、生物量及主要的土壤化学成分;采用了模糊聚类、系统聚类及多元线性回归等方法分析藻类的群落及其与环境因子的关系。共鉴定出21种蓝藻,其中6种为国内首次报道。研究表明:土壤含磷量、总盐量及与粘性和湿度有关的土壤结构是决定柴达木盆地蓝藻群落组成的重要因素。     

鹅掌楸种子和胚胎发育的研究

应用控制授粉、软 X-射线法、常规石蜡制片法和荧光检测等手段,研究了鹅掌楸(Lirio-dendron chinense(Hemsl.)Sarg.胚胎发育和控制授粉与结籽率的相关性。控制授粉后2小时花粉萌发,6小时萌发率最高,柱头可授期持续30小时左右。花粉管借助于柱头毛之间的分泌物进入柱头沟,经花柱沟、珠孔塞和珠心冠原进入胚囊,行珠孔受精。授粉后2周,胚乳为2至3细胞厚的狭组织;第6周,胚乳充满胚囊腔,珠心随之解体殆尽;第7到8周,球形胚、心形胚发生;第14到16周,子叶形成;第22周种子或熟,胚乳丰富。单株自然授粉结籽率不足1%。控制授粉后,单个聚合果的最高结籽率可达39%,9个聚合果的平均结籽率为17.7%。     

Isolation and culture of protoplasts of pigeonpea (Cajanus cajan L.)

Summary High yields of protoplasts were obtained from leaves of aseptically grown plants and calli originated from different explants, in several cultivars of Cajanus cajan L. The protoplasts divided to form cell clusters in modified KM 8p medium and developed to protocolonies after dilution with liquid Caboche's medium within three to four weeks of culture. The protocolonies proliferated to form green calli on solid Caboche's medium. No shoots or plants were obtained.Abbreviations BAP 6-benzylaminopurine - NAA -napthaleneacetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - Kin kinetin - Zea zeatin - Adn S adenine sulphate - GA ₃ gibberellic acid     

Pericellular substrates of human mast cell tryptase: 72,000 dalton gelatinase and fibronectin.

Migrating cells degrade pericellular matrices and basement membranes. For these purposes cells produce a number of proteolytic enzymes. Mast cells produce two major proteinases, chymase and tryptase, whose physiological functions are poorly known. In the present study we have analyzed the ability of purified human mast cell tryptase to digest pericellular matrices of human fibroblasts. Isolated matrices of human fibroblasts and fibroblast conditioned medium were treated with tryptase, and alterations in the radiolabeled polypeptides were observed in autoradiograms of sodium dodecyl sulphate polyacrylamide gels. It was found that an M(r) 72,000 protein was digested to an M(r) 62,000 form by human mast cell tryptase while the plasminogen activator inhibitor, PAI-1, was not affected. Cleavage of the M(r) 72,000 protein could be partially inhibited by known inhibitors of tryptase but not by aprotinin, soybean trypsin inhibitor, or EDTA. Fibroblastic cells secreted the M(r) 72,000 protein into their medium and it bound to gelatin as shown by analysis of the medium by affinity chromatography over gelatin-Sepharose. The soluble form of the M(r) 72,000 protein was also susceptible to cleavage by tryptase. Analysis using gelatin containing polyacrylamide gels showed that both the intact M(r) 72,000 and the M(r) 62,000 degraded form of the protein possess gelatinolytic activity after activation by sodium dodecyl sulphate. Immunoblotting analysis of the matrices revealed the cleavage of an immunoreactive protein of M(r) 72,000 indicating that the protein is related to type IV collagenase. Further analysis of the pericellular matrices indicated that the protease sensitive extracellular matrix protein fibronectin was removed from the matrix by tryptase in a dose-dependent manner. Fibronectin was also susceptible to proteolytic degradation by tryptase. The data suggest a role for mast cell tryptase in the degradation of pericellular matrices.     

The disposition of venlafaxine enantiomers in dogs, rats, and humans receiving venlafaxine.

A stereospecific high-performance liquid chromatographic (HPLC) method was developed for the quantitation of the enantiomers of venlafaxine, an antidepressant, in dog, rat, and human plasma. The procedure involves derivatization of venlafaxine with the chiral reagent, (+)-S-naproxen chloride, and a postderivatization procedure. The method was linear in the range of 50 to 5,000 ng of each enantiomer per ml of plasma. No interference by endogenous substances or known metabolites of venlafaxine occurred. Studies to characterize the disposition of the enantiomers of venlafaxine were conducted in dog, rat, and human, following oral administration of venlafaxine. The Cmax, area under the curve (AUC) and (S)/(R) concentration ratios of the (R)- and (S)-enantiomers were compared. In rats, the mean plasma ratio of (S)-venlafaxine to that of (R)-venlafaxine over 0.5 to 6.0 h varied from 2.97 to 8.50 with a mean value of 5.51 +/- 2.45. The Cmax, AUC0-infinity, and t 1/2 values of the (R)- and (S)-enantiomers in dogs were not significantly different from one another (P greater than 0.1). The mean ratios [(S)/(R)] of enantiomers of venlafaxine in human over a 2 to 6 h interval ranged from 1.33 to 1.35 with an overall ratio of 1.34 +/- 0.26 (n = 12). These ratios of the enantiomers [(S)/(R)] were not statistically different from unity (P greater than 0.1) indicating that the disposition of venlafaxine enantiomers in humans is not stereoselective and is more similar to that in dogs than that in rats.     

Cytochrome P-455 nm complex formation in the metabolism of phenylalkylamines. XII. Enantioselectivity and temperature dependence in microsomes and reconstituted cytochrome P-450 systems from rat liver.

Formation of metabolic intermediate (MI) complexes was studied with the enantiomers of amphetamine, 1-phenyl-2-pentanamine, N-hydroxyamphetamine, and 2-nitroso-1-phenylpropane (the C-nitroso analogue of amphetamine). Three different enzyme systems were used; liver microsomes from phenobarbital pretreated rats and two reconstituted systems containing the P450 2B1 and P450 2C11 forms of cytochrome P-450. Enantioselective complex formation in microsomes was shown for the amines and the nitroso compound, but not for the hydroxylamine. The highly purified P450 2B1 system formed the MI complex with all substrates tested, and the enantioselectivity observed with the microsomal system was reproduced. In the P450 2C11 system the nitroso compounds were completely inactive, whereas the enantiomers of N-hydroxyamphetamine still produced the complex at a high rate. Changes in temperature were shown to affect (R)-2-nitroso-1-phenylpropane more than its enantiomer. Both enantiomers showed biphasic Arrhenius plots for MI complex formation in microsomes (breaks around 22 degrees C), but the activation energies of the (R)-isomer were about five times higher than those of the (S)-isomer. A theory is presented which suggests different modes of interaction with the active site of P-450 to account for the different behaviour of the various substrates.     

Antitumor effect of RBS (rice bran saccharide) on ENNG-induced carcinogenesis

We examined whether orally administered RBS (rice bran saccharide), prepared from rice bran by hot water extraction, increases immunocompetence, inhibits gastrointestinal carcinogenesis with N-ethyl-N-nitro-N-nitrosoguanidine (ENNG) or shows an antitumor effect. After the administration of RBS, phytohemagglutinin (PHA)- and pokeweed mitogen (PWM)-stimulated blastogenesis of lymphocytes derived from the mesenteric lymph nodes and peripheral blood was enhanced, and the helper/ suppressor T-cell ratio was elevated, and migration activity of peritoneal macrophages was also increased in rats treated continuously with ENNG. ENNG-induced gastrointestinal carcinomas were observed in 43% of those administered RBS (ENNG-RBS) as compared with 88% in the control (ENNG) and 94% in the prednisolone (PRD) group (ENNG-PRD). The 12-month survival rate of rats bearing gastrointestinal cancer was 58% in the ENNG-RBS group as compared with 25% in the ENNG group and 15% in the ENNG-PRD group. RBS prevented the reduction in immunocompetence in the course of carcinogenesis, suppressed carcinogenesis, and prolonged the survival of rats with gastrointestinal cancer. Antitumor activities of RBS are thought to be a kind of host mediated action. The growth inhibition ratio of transplantable ENNG-induced cancer in Wistar rats was 42.1% in the RBS and 51.8% in the 5-FU group. Since little is known about the potent antitumor activity of -glucan, it would be interesting to consider the relationship between the structure and the biological activities of polysaccharides.     

Effect of pyridoxine on tumor necrosis factor activitiesin vitro

Clinical trials with tumor necrosis factor (TNF) as an antitumor agent have so far given rather disappointing results. In this study we show that the naturally occuring vitamin B₆ compound, pyridoxine, enhances TNF-induced cytolysis of three subclones of a mouse fibrosarcoma cell line (WEHI 164). The degree of pyridoxine-induced enhancement of TNF cytotoxicity seems to be dependent on the cells sensitivity to TNF, as the enhancement was much more pronounced in the relatively TNF resistant subclone act-R(cl.12)-WEHI 164, than in the very TNF sensitive subclone WEHI 164 clone 13. Furthermore, our study shows that pyridoxine, in contrast to its enhancing effect on TNF-induced cytotoxicity, rather inhibits TNF-induced growth of human FS-4 fibroblasts. Pyridoxine also enhances lymphotoxin (LT)-induced tumor cell killing and inhibits LT-induced fibroblast growth. Pyridoxine is a relatively non-toxic agentin vivo. Our results suggest that a combination of TNF and pyridoxine may be more efficient than TNF alone, in the treatment of cancer patients.