Effects of subacute treatment with cocaine on activities of N-demethylase, UDP-glucuronyltransferase and sulfotransferase in WKY and SHR rat liver--sex and strain differences

The effects of subacute treatment with cocaine on activities of cocaine N-demethylase, UDP-glucuronyltransferase (GT) toward 4-nitrophenol and phenolphthalein and sulfotransferase (ST) toward androsterone and 4-nitrophenol in livers from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were investigated. Hepatic metabolism of cocaine was different between the sexes (with males having higher N-demethylase activity) and the strains (with WKY rats having higher activity). The effects of subacute cocaine administration on the activity of cocaine N-demethylase were also sex- and strain-related. Whereas cocaine administration increased activity of hepatic N-demethylase in both female strains, it decreased activity in male WKY and had no effect on activity in male SHR. Sex and strain-related as well as cocaine-induced differences were also found in activities of hepatic GT toward 4-nitrophenol and phenolphthalein as well as in activity of hepatic ST towards andersterone and 4-nitrophenol. These results suggest that some of the individual variation in the effects of cocaine may be due to sex and genetic differences in the hepatic metabolism of cocaine and/or in sexually and/or/genetically-determined differences in how cocaine affects hepatic metabolism of other xenobiotics.     

Formation of Ascorbate Oxidase in Cultured Pumpkin Cells

Ascorbate oxidase activity rapidly increased during callus formationfrom pumpkin fruit tissue. The activity reached a maximum at5 days after transfer and then declined. In callus which hadbeen subcultured at about 4-week intervals for more than oneyear, the activity also increased after transfer to fresh mediumand reached a maximum in the early logarithmic phase of growth.Light had little effect on the appearance of ascorbate oxidaseactivity in pumpkin callus. In the callus grown in the presenceof 10µM CuSO₄, the activity was about 10 times that inthe presence of 0.1 µM CuSO₄, suggesting that the formatonof ascorbate oxidase in pumpkin callus is stimulated by copper,a prosthetic metal of the enzyme. From 45 to 75% of the totalascorbate oxidase activity in pumpkin cell suspension cultureswas found in the medium. Ascorbate oxidase activity in the medium,as well as that in the cells, increased soon after transferto fresh medium, and reached a maximum at about 5 days. (Received July 2, 1987; Accepted November 21, 1987)     

Defective production of and response to IL-2 in acute human falciparum malaria

Patients with acute Plasmodium falciparum malaria have defective cell-mediated immune responses to malaria-specific Ag (MA). This immunologic defect may partially explain the difficulty with which natural immunity to falciparum malaria develops and may have important implications for the efficacy of potential malaria vaccines in endemic areas. To investigate the basis of this immune defect, we have examined the capacity of PBMC from patients with acute falciparum malaria to produce IL-2 and to express I1-2R in response to Ag stimulation. The effect of exogenous IL-1 and IL-2 on lymphocyte proliferation was studied. Soluble IL-2R levels were measured in acute and convalescent sera. Our results showed that no detectable IL-2 was produced and no IL-2R were expressed by PBMC in response to MA during the acute infection. IL-2 production and IL-2R expression were also depressed when PBMC were exposed to streptococcal Ag. The specific immune defect was not reconstituted by the addition of graded doses of purified human IL-1 or IL-2 and could not be attributed to suppressor adherent cells. In contrast to the absence of IL-2 and cell-bound IL-2R, circulating soluble IL-2R was elevated in acute sera. These findings suggest that the lack of IL-2, through either a defect in its production or inhibition of its activity, may be the basis of the Ag-specific immune unresponsiveness in acute P. falciparum malaria.     

Hormonal regulation of gene expression in barley aleurone layers

As part of our investigation of the mode of action of plant hormones in barley (Hordeum vulgare L.) aleurone layers, we have studied the expression of five identified and three unidentified mRNA species in the presence of exogenous gibberellic acid (GA₃) and abscisic acid. Three of the mRNAs are GA₃-inducible, three are suppressed by GA₃, and two are constitutive. The extent of the GA₃ effect differs considerably for both inducible and suppressible mRNAs. For example, a ten-fold higher concentration of GA₃ (10^-8 M) is required for full induction of the high-pl group -amylase mRNA than is required for the low-pI -amylase mRNA (10^-9 M). Temporal regulation of mRNA abundance also varies between the two -amylase isoenzyme groups. The three GA₃-suppressible mRNA species studied, alcohol dehydrogenase (ADH1), a probable amylase and protease inhibitor, and an unidentified barley mRNA species also varied in response to GA₃. The ADH1 mRNA decreased drastically within 8 h of GA₃ treatment, whereas the other two began to decrease in abundance only after 12–16 h of GA₃ treatment. Abscisic-acid treatment counteracted the GA₃ effects for both the inducible and suppressible mRNA species. Comparison of -amylase-mRNA levels and -amylase-synthesis rates showed a strong correlation between the two parameters, the only exception being a lack of -amylase synthesis in the presence of -amylase mRNA at low GA₃ concentrations. Therefore, the expression of -amylase seems to be regulated primarily by its mRNA levels.Abbreviations ABA abscisic acid - ADH1 alcohol dehydrogenase 1 - cDNA copy DNA - GA₃ gibberellic acid - PAPI probable amylase/protease inhibitor     

三个与agropine合成相关的基因在大肠杆菌微细胞中的表达

pTiAch 5 TR区与在植物中积累agropine相关的三个基因片段已导入pINIIA或pACYC184,在大肠杆菌微细胞中表达出杂合蛋白。三个基因片段的pINIIA重组质粒的表达得到稳定蛋白、不稳定蛋白和在两个相表达出相似蛋白的三种结果。基因2'HindⅢ片段上的UGAA序列是在两个相表达相似蛋白的原因。从产生的杂合蛋白分子量和读码方式看,pTiAch 5中基因2'和基因1'的结构与pTi 15955近似,但由基因0'片段产生的杂合蛋白分子量比根据pTi15955 DNA序列数据推测的稍大。从表达强度和微细胞操作看,这个系统还不适应从大肠杆菌中方便地纯化杂合蛋白的需要。     

Selective failure of androgens to regulate follicle stimulating hormone beta messenger ribonucleic acid levels in the male rat

FSH beta, as well as LH beta, and alpha-subunit mRNA levels were examined in the pituitary glands of male rats after sex steroid replacement at various times (7, 28, or 90 days) after orchiectomy. Testosterone propionate, dihydrotestosterone propionate, or 17 beta-estradiol benzoate (E) were administered daily for 7 days before killing, to assess the role of different gonadal steroids on gonadotropin subunit mRNA levels. Subunit mRNAs were determined by blot hybridization using rat FSH beta genomic DNA, and alpha and LH beta cDNAs. At all time points, alpha and LH beta mRNAs increased after gonadectomy and fell toward normal levels with either androgen or estrogen replacement. FSH beta mRNA levels increased variably postcastration: 4-fold at 7 days, 2-fold at 28 days, and 4- to 5-fold at 90 days. Although E replacement uniformly suppressed FSH beta mRNAs, neither testosterone propionate nor dihydrotestosterone propionate administration suppressed FSH beta mRNA levels at any time point after orchiectomy. These data demonstrate that there is a relative lack of negative regulation of FSH beta mRNA levels by androgens in a paradigm in which E administration results in marked negative regulation of FSH beta mRNA levels. Thus, in the male rat, estrogens negatively regulate all three gonadotropin subunit mRNA levels while androgens negative regulate LH beta and alpha-subunit but fail to suppress FSH beta mRNAs.     

青天葵野生变家栽的探讨——Ⅰ.生物学特性的观察

青天葵是广西特产药材,过去一直处于野生状态,药源日渐枯竭.供不应求。作者通过调查和研究,掌握了它的生态条件和生物学特性。实践证明,青天葵由野生变为人工栽培是可能的。     

Phosphorylation of proteins in Xanthomonas campestris pv. oryzae

Protein phosphorylation was studied in Xanthomonas campestris pv. oryzae in vivo and in vitro. In vitro labelling showed that the protein kinases in this bacterium used both ATP and GTP as nucleotide substrates at nearly the same efficiency. At least 6 proteins were phosphorylated in vitro, including abundant species of p81, p44, and p32 with M _r of 81000, 44000, and 32000, respectively. Three types of phosphate-protein linkage were found in this bacterium: O-phosphate, N-phosphate and probably acyl phosphate. The p81 and p32 were phosphorylated at histidine. The p44 had mainly phosphoserine and a small part of phosphohistidine. The phosphorylation profile was variable depending on the growth conditions. Furthermore, by a virulent phage Xp10 infection the quantity of phosphorylation increased: for phosphohistinine more than 10-fold, and for phosphoserine about 3-fold. Thus, in this bacterium phosphorylation may be linked with a physiological regulation system and with Xp10 phage development.