Various aspects of lipid metabolism in the rat testicle after sulpiride treatment]

Testicular lipids were extracted from 20 rats which had received 40 mg sulpiride per kg per day for 20 days as well as from 20 controls. The extracts were weighed and chromatographed on thin layer in order to analyse them for the main fatty constituants : phospholipids and neutral fats. In addition total cholesterol, triglycerides and lipid phosphorus were determined. The total testicular lipid content and the phospholipids were unaltered. The distribution of phospholipids wasn't influenced either. Among the neutral fats the precursors of steroid hormones such as cholesterol and its esters didn't show any modification. The triglycerides on the other hand suffered a significant decrease which was partly compensated in situ by the increase of free fatty acids. Since plasma electrophoresis didn't reveal a parallel increase of the complex albumin--free fatty acids, the hypothesis of an in situ lipolysis is proposed. But it is not possible yet to attribute to sulpiride the role of a direct activation on a testicular triglyceride lipase nor that of an indirect activator by way of prolactine for example.     

Various methodological aspects of biochemistry

Certain methodological problems of present-day biochemistry are considered. Comprehension of the mechanisms of biochemical processes is shown to be possible on the basis of the structural and functional analysis at the molecular level. Ways of development and use of structural and functional approach to studies of supermolecular structures, cells and organisms on the whole are discussed.     

Various aspects of protoplast production in Streptococcus lactis

The authors studied the effect of some factors, including the conditions of preincubation, the action of 2-mercaptoethanol, EDTA, alpha-amylase, on protoplast production in four strains of Streptococcus lactis caused by lysozyme. The strains differed in the nisin-producing activity and in the structure of the cell walls that were not affected with lysozyme without either preincubation in 2-mercaptoethanol or in a salt medium with minimal inhibitory concentrations of DL-threonine. EDTA and alpha-amylase increased the lysozyme effect. Among seven buffer systems studied the most favourable for protoplast production in S. lactis is the ammonia-citric buffer with EDTA, and the best regeneration medium is the agar salt medium to which, depending on the strain, either glucose or sucrose should be added as a stabilizer.     

Various aspects of transplacental blastomogenesis in rabbits]

Transplacental blastomogenic action of different carcinogenic agents (ethylnitrosourea--ENU), methylnitrosourea--MNU, dimethylbenzanthracene--DMBA, and benz(a)pyrene--BP) was studied in rabbits. As revealed, ENU had the greatest blastomogenic activity and an expressed neurotropic action. Relative tropism to different tissues characteristic of some carcinogenic agents during their action on adult organism was not always expressed in transplacental blastomogenesis, Study of the influence of different modifying factors (organospecific immunization, chronic irritation of the peripheral nerve, injection of the MNU) on the realization of transplacental blastomogenesis showed that their postnatal use stimulated mostly the appearance of the peripheral nerve timours in the offspring rabbits (MNU inhibited the development of tumours).     

Measurement of sulfur-containing compounds involved in the metabolism and transport of cysteamine and cystamine. Regional differences in cerebral metabolism

An HPLC method with coulometric detection is presented for the quantitation of cysteamine, cystamine, thialysine, glutathione, glutathione disulfide and an oxidized metabolite of thialysine [S-(2-aminoethyl)-l-cysteine ketimine decarboxylated dimer (AECK-DD)]. The advantage of coulometric detection is that derivatization is unnecessary if the analyte is redox sensitive. The method was used to quantitate several sulfur-containing compounds in plasma and brain following gavage feeding of cysteamine to rats. Cysteamine, cystamine, thialysine and AECK-DD were detected in the brains of these animals. Interestingly, cysteamine treatment resulted in greatly elevated levels of cerebral methionine, despite the fact that cysteamine is not a precursor of methionine.     

Various aspects of topogenesis of foreign proteins

The paper considers some aspects of the processing of precursors of foreign proteins, their interaction with the secretory system, directed changes of protein compartmentalization, and protection of foreign proteins from proteolysis.