Short-term inhibition of carnitine palmitoyltransferase I activity in rat hepatocytes incubated with ethanol

Ethanol decreased the activity of carnitine palmitoyltransferase I and the rate of fatty acid oxidation in rat hepatocytes in short-term incubations. These effects were mimicked by acetaldehyde, the product of hepatic ethanol metabolism, and were absent when ethanol oxidation was prevented by 4-methylpyrazole. Ethanol was also able to increase intracellular malonyl-CoA levels. The results suggest that inhibition of fatty acid translocation into mitochondria may play an important role in the ethanol-induced inhibition of hepatic fatty acid oxidation.     

Age-related changes in the translocation of phosphatidate phosphohydrolase from the cytosol to microsomal membranes in rat liver

The effects of oleate, spermine and chlorpromazine were assayed in the presence or absence of 0.15 M KCl on the translocation of phosphatidate phosphohydrolase activity from cytosol to endoplasmic reticulum membranes in liver homogenates obtained from rats aged 1, 30, 60, 180 and 360 days. Marked age-associated decreases in phosphatidate phosphohydrolase distribution onto the membranes were demonstrated under nearly all conditions. In liver homogenates taken from 1-day-old rats and incubated with 0.15 M KCl, most of the enzyme was active (associated with the membranes). Physiological salt concentration (0.15 M KCl) produced a 2-fold increase of oleate-induced translocation of phosphatidate phosphohydrolase activity in liver homogenates from 1-day-old rats; it had no effect on those from 60-day-old rats, and produced a notable decline in liver homogenates obtained from 180- and 360-day-old rats. The promoting effect of spermine on oleate-induced translocation of this enzyme activity was higher in younger rats when incubated in the absence of 0.15 M KCl. Chlorpromazine did not show its usual antagonizing effect on oleate-induced translocation of phosphatidate phosphohydrolase when added to homogenates taken from 1-day-old rats. The antagonizing effect was slightly apparent in liver homogenates from 30-day-old rats and was more pronounced in those from 60-day-old rats in which the values diminished to one-half and to one-third either in the presence or absence of 0.15 M KCl.     

Maintenance of aPaecilomyces variotii culture in the frozen and Freeze-dried state and in distilled water

The highest number of viable.elements ofPaecilomyces variotii, forming colonies after a 1-year maintenance, was detected in frozen sample. Decreased viability of the frozen culture and culture maintained in distilled water was usually statistically significant after 1 year and decreased further with increasing age of the culture used for sample preparation. Freeze-drying also significantly decreased the strain viability, depending on culture age. In the freeze-dried culture stored in a refrigerator the relative number of viable elements was substantially higher than after storage at room temperature. After a 3-year storage of freeze-dried P.variotii in a refrigerator 14-44% of culture elements survived, as compared with the number detected immediately after freeze-drying.     

Saprophytic production of Clavine alkaloids and activity of Hydroxymethylglutaryl-CoA reductase

In submerged Claviceps cultures the activity of hydroxymethylglutaryl-CoA reductase preceded the increase of alkaloid production and of sterol content. During the first alkaloid phase, cell mevalonate was involved in the biosynthesis of both alkaloids and steroids. In the second production phase, it was predominantly used for alkaloid synthesis. Hydroxymethylglutaryl-CoA reductase appears to be a suitable target for physiological manipulation to increase clavine alkaloid yields.     

The adhesin structures involved in the adherence of group B streptococci to human vaginal cells

The adherence of group B streptococci (GBS) of serotypes Ia, II and III to human vaginal cells was studied in vitro. The adherence was not dependent on the viability of bacteria; killing of GBS by UV irradiation or glutaraldehyde treatment did not inhibit the adherence. Killing of GBS by heating to 56 degrees C for 1 h led to a pronounced decrease of adherence, demonstrating the thermosensitivity of the GBS structures involved. The protein nature of these structures was proved by a significant reduction of adherence after pretreatment of GBS with trypsin or pepsin. Pretreatment of GBS with sialidase had no influence on the adherence. Such a pretreatment of vaginal cells caused an increase of adherence showing that the receptors on epithelial cells may be partly masked by sialic acid.     

Trifluoperazine inhibits thyrotropin-releasing hormone-stimulated TSH secretion

In previous work changes of the thyrotropic secretion after administration of some substances affecting the calcium content in the cytosol were demonstrated. The object of the present investigation was to assess the hormonal response to the administration of trifluoperazine, a psychopharmaceutical preparation, the main mechanism of its action being the inactivation of the cytosol receptor for the calcium signal - calmodulin. The poor utilization of intracellular calcium of the secretory cell is then the factor which inhibits secretion proper. The thyrotropic secretory reserve (delta TSH) was assessed in the same subjects before and after trifluoperazine administration by the TRH test as the difference of values at rest and TRH-stimulated TSH levels during the 20th, 30th, 40th and 60th minute following intravenous administration of 200 micrograms TRH. It was revealed that this calmodulin antagonist administered for one week in amounts of 6-12 mg per day by mouth significantly inhibits the secretory response of TSH to TRH in healthy subjects during the 20th and 40th min. (P less than 0.05). The reproducibility of the TRH test repeated in a group of subjects not treated with trifluoperazine, however, under equal conditions and after the same time intervals as in the experiment with trifluoperazine was very satisfactory and thus physiological inhibition caused by repeated TRH administration could be ruled out. The inhibition of the secretory TSH response to TRH can be therefore considered the consequence of the direct effect of trifluoperazine on the thyrotropic secretory mechanism. Trifluoperazine significantly reduced serum calcium levels and raised phosphate levels, while it did not affect the blood levels of magnesium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of amphetamine-induced changes in the behavior of adult "aunts" on development and long term behavioral patterns of rats

Infant rats of the Wistar strain were kept either with their mother or with both the mother and the "aunt"--an adult virgin female during the suckling period. One group of aunts was injected regularly with amphetamine in the dose of 3 mg/kg b.w. (the AA group), another group with saline (the SA group). Control (CO) pups were reared by their mother only. Both acute and long term consequences of aunt-rearing on behavioral development and growth rate were observed. On Days 25 and 28 the SA pups displayed an increased exploratory activity level and more contacts with the litter-mate in the test of paired interactions when compared with both the AA and CO groups. The lowest frequency of exploratory, of manipulatory and social activities were recorded for the AA pups. In adulthood, both the aunt-reared groups of male rats exhibited higher activity level in a novel environment than the CO males. However, while in the CO and the SA males the activity level tended to habituate over the repeated tests, in the AA it persisted on a high level. The difference among females was not significant. Growth rate was retarded in the AA male and female rats.