Transformation of microcrystalline hydrocortisone by free and immobilized cells of Arthrobacter simplex.

The transformation of microcrystalline hydrocortisone by free and immobilized cells of Arthrobacter simplex resulted in formation of prednisolone. The effect of medium composition, non-ionogenic surfactants and exogenous electron acceptors on the delta 1-dehydrogenase activity of free and immobilized cells is described.

Studies on the mechanism of the changes in serum and liver gamma-glutamyl transpeptidase activity. II. Experimental hexachlorobenzene porphyria in rabbits.

The mechanism responsible for the changes in serum and liver gamma-glutamyl transpeptidase (gamma-GT) activity was studied in a model of experimental hexachlorobenzene porphyria in rabbits. Porphyria followed the administration of hexachlorobenzene in doses of 280 mumol - kg-1 body weight, which were given daily through a gastric tube over a 20-day period. Serum gamma-GT activity and the activities of the lysosomal enzymes beta-N-acetylglucosaminidase and alpha-mannosidase were increased, whereas L-aspartate: 2-oxoglutarate aminotransferase and L-alanine: 2-oxoglutarate aminotransferase and L-alanine: 2-oxoglutarate aminotransferase remained unaltered. There was a considerable increase in liver microsomal protein, gamma-GT, cytochrome P-450, anilinehydroxylase, aminopyrine-demethylase and delta-aminolevulinic acid synthase. In the liver gamma-GT was detected in the microsomes as well as in the cytoplasm where enzymatic activity was higher. The high correlation coefficient between liver gamma-GT, cytochrome P-450 and delta-aminolevulinic acid synthase witnesses a hexachlorobenzene-induced gamma-GT formation in the liver. A statistically significant correlation between serum and liver gamma-GT activity was also found. These data strongly suggest that the increase in serum gamma-GT activity may result from the induction of the enzyme in the liver.

[Histological, histoenzymatic and biochemical study of the liver and small intestine of rats during short periods of starvation]. / Gistologicheskoe, gistoénzimaticheskoe i biokhimicheskoe issledovanie pecheni i tonkogo kishechnika krys pri neprodolzhitel'nom golodanii

The structure and the activity of acid phosphatase, beta-glucuronidase, alkaline phosphatase and ATP-ase in the liver and small intestine of rats receiving for 20 days a one-time, fixed at a certain time (2 o'clock) feeding was studied morphologically in dynamics in 2, 6, 24 and 48 hours after the last feeding. Furthermore, parallel with this the activity of acid phosphatase, beta-glucuronidase, alpha-glucosidase and beta-acetylglucosaminidase was determined in homogenates by biochemical methods. Alongside the total activity free activity of beta-acetylglucosaminidase and the activity of this enzyme in the blood plasma was defined. It is shown that during fasting, especially by the 48th hour, there takes place a significant activation of lysosomal enzymes both in the liver and in the small intestine (in the cells of the cylindrical epithelium). A significantly increased permeability of lysosomal membranes (mounting free activity of beta-acetylglucosaminidase) in the liver and of plasmic hepatocytes membranes (higher activity of the enzyme in the blood plasma) was also ascertained. The activation of the lysosomal enzymes is considered to be an adaptive reaction of the organism in fasting.

[Effect of short-term fasting on liver lysosomes in rats, biochemical studies (preliminary report)]. / Vliianie na kratkotrainoto gladuvane vurkhu lizozomite na cherniia drob u plukhove--biokhimichni izsledvaniia (predvaritelno suobshtenie).

The total activity of four lysosome enzymes--acid phosphatase, beta-glucuronidase, alpha-glucosidase and beta-N-acetylglucosaminidase--is studied in liver homogenate at 2, 6, 24 and 48 hours after the last meal in rats, previously sustained on a single-daily-feeding regimen. In addition, the free activity (percentage of the total) of the latter enzyme and its activity in the serum as well are investigated. A rise of the total activity of the first three enzymes is recorded within 48 hours after the beginning of starvation. The free activity of beta-N-acetylglucosaminidase shows an increase at 48 hours, while its activity in the serum--as early as 24 hours. The changes described above are interpreted as an expression of lysosome membrane permeability enhancement under fasting conditions.

[Changes in lysosome enzymatic activity during fasting following a regimen of once-a-day or all-day feeding]. / Promeni v aktivnostta na niakoi lizozomni enzimi pri gladuvane sled rezhim na ednokratno ili tselodnevno khranene.

The influence of fasting for 24-96 hours is studied in rats, subjected in advance to a regimen of all day long access to food, to a single feeding in 24 hours. Total activity of beta-N-acetylglucosaminidase (beta-N-AcG1), acid phosphatase (AP) and beta-glucuronidase, as well as the free activity of the first two enzymes are studied in liver homogenate. The activity of beta-N-AcG1 is determined in blood serum also. A rise of total beta-N-AcG1 activity is recorded in liver homogenate, increasing parallel to prolongation of the fasting period. The changes in free activity of AP and beta-N-AcG1, and in the plasma activity of the latter enzyme are similar. The above described changes are more strongly pronounced in the groups subjected in advance to a single feeding regimen. These changes are interpreted as an expression of the active participation of lysosomes and their enzymes in the transition to endogenic nutrition. The lysosome membrane proves to be more vulnerable to damage by starvation among the animals previously maintained on a single feeding regimen.

[Changes in protein metabolism in white rats with limited feeding and a varying physical load]. / Promeni v beltuchniia obmen na beli plukhove pri ogranicheno khranene i razlichno fizichesko natovarvane.

Changes in some protein metabolism indicators are studied in white rats at different levels of the energy balance. It is established that the level of the so-called labile protein in the organism is closely related to the level of energy metabolism and also, that it is not invariably directly dependent on protein concentration within the organism. The inference is reached that adaptivity of protein metabolism is manifested not merely through changes in the value of proteins, which might be employed in the capacity of reserve, but also through changes in the degree of their lability, resp. in the ability of the organism to mobilize them. The amount of protein reserves depends rather more on the increased protein intake with the while food, while the degree of reserve protein lability is related to a higher degree to the muscular activity of the organism. Restricted motor activity combined with a high protein intake, against the background of an even minimum hypercaloric feeding, leads to a considerable reduction of protein reserves. Deficient feeding combined with restricted motor activity leads to reduction both of the amount and lability of reserve proteins. Physical exertions have a favourable effect on the ability of organism both to increase its protein reserves and to mobilize them, with the latter being rather pronounced under conditions of limited feeding. It is stressed that excretion of nitrogen, urea and creatinine in the urine in conditions of protein poor diet is in a position to afford essential information on the adaptability of protein metabolism within the organism.

[Changes in the serum activity of lysosome enzymes in rats after application of the insecticide propoxur (Baygon)]. / Promeni v serumnata aktivnost na niakoi lizozomni enzimi u plukhove sled prilaganeto na insektitsida propoksur (baigon).

The effect of repeated peroral introduction (4 times) of 1/4 and 1/20 LD50 of monomethylcarbamate insecticide Propoxur (Baygon) on the activity of two lysosomal enzymes (beta-N-acetylglucosaminidase and alpha-mannosidase) is studied in the serum of white male rats with starting weight 300 g. Upon using the higher dose, a statistically significant rise (p less than 0.02) of the activity of either of the enzymes is established. The results obtained are interpreted as a sign of impaired permeability of the lysosomal and cell membrane.