The effect of the acidity of the medium on the magnitude of the light-dependent antibacterial activity of chlorophyllides]

The influence of medium acidity on the intensity of light-dependent antibacterial activity of chlorophyllides isolated from biomass of microscopic green alga Westella botryoides has been studied. This light-dependent antibacterial activity has been shown to be maximum at low pH values. The ability to suppress the bacterial growth under the action of light decreases in neutral and alkaline media. It has been concluded that the reason of increase of light-dependent antibacterial activity of chlorophyllides at low pH values is formation of pheophorbides out of them     

Enzyme histochemistry and hormones of the developing gastrointestinal tract of the chick embryo

Summary In this investigation glueagon has been histochemically demonstrated by the fluorescent antibody technique in the developing gastrointestinal tract of the chick embryo. The levels of monoamine oxidase activity at various stages during the development of the gastrointestinal tract has been studied. Both monoamine oxidase activity and argentaffin positive cells have been demonstrated histochemically in the epithelial cells of the embryonic stomach-complex and intestine. This similarity in the localisation suggests that monoamine oxidase activity may be related with the seratonin producing cells.     

Hypotrypsinemia as a possible factor in the activation of motor function of the duodenum in pancreatic atrophy in rats]

The effect of pancreas atrophy on myoelectrical activity of the duodenum and serum trypsin, trypsin inhibitor, amylase, lipase activity has been described. The activation of the duodenum motor activity has been established. The changes in the motor activity were connected with trypsin and trypsin inhibitor activity of serum. The motor activity changes were compensated by trypsin therapy.     

The characteristics of protein hydrolysis on the digestive-transport surfaces of the cestode Eubothrium rugosum and of the intestines of its host--the burbot]

The functioning of different proteinases hydrolysing proteins in a wide pH range, most of which display activity in the alkaline zone of pH, on the digestive-absorptive surfaces of the parasite and host has been investigated. The dynamics of desorption of these proteinases from the intestine of fishes and tegument of cestodes has been studied. It has been shown that the worms possess less proteolytic activity and less capacity for adsorption of proteinases as compared to the intestines of their hosts. The dependence of proteolytic activity of desorbed fractions on the incubation medium temperature has been noted: with the increase in temperature the enzymes, bound closely with the membranes, increase their capacity to hydrolyse proteins. The predominance in cestodes, as compared to the intestine, of easily desorbed fractions D1 and D2 (in the percent ratio of the total proteolytic activity of all fractions) has been detected.     

Changes in the activity of the brain renin-angiotensin system and in the functional state of the pituitary-adrenal system of rats under the influence of captopril]

While studying the effect of peroral captopril injections on the activity of renin-angiotensin system (RAS), the activity of angiotensin-converting enzyme (ACE) and angiotensin II content from anterior and mediobasal hypothalamus, medulla and adenohypophysis of intact rats has been established to decrease. Captopril administration decreases ACE activity which increases after hydrocortisone injection in rat medulla and striatum. Captopril results in no potentiation of hormonal effect in hypothalamus and in adenohypophysis where ACE activity decreases following hydrocortisone injection. A decrease in the RAS activity of brain structures and adenohypophysis induced by captopril administration to rats is accompanied by the inhibition of the activity in the pituitary-adrenal system. A decrease in ACTH level and in 11-hydroxycorticosteroids of the rat blood plasma has been determined after single captopril injection in the dosage of 10 and 50 mg/kg of body weight. Duration of the effect depends on the captopril dosage.     

Diurnal variation of the acid phosphatase activity in the leaves of Cowpea

Summary The activity of acid phosphatases (glycerophosphatase, phenylphosphatase and pyrophosphatase) in Cowpea (Vigna catjang) leaves has been studied at different hours of the day and a marked diurnal variation has been observed. The phosphatase activity in leaves collected between 10 A.M. to 2 P.M. was always higher than in leaves collected earlier in the morning and late at evening. Pyrophosphatase activity exhibited greater variation than phenylphosphatase and glycerophosphatase activity. The significance of the increased phosphatase activity is discussed in relation to the production of carbohydrates from organic acids in light.     

State of the system of antioxidant defense in tissues of the black sea turbot during the spawning

The system of antioxidant (AO) defense and processes of lipid peroxidation (LP) of the Black Sea turbot Psetta (Scophtalmus) maxima maeotica (L., 1758) have been investigated during the spawning season. The activity of glutathione peroxidase (GP), glutathione reductase (GR), catalase and content of reduced glutathione (GSH) and TBA-reactive products have been determined in gonads, gills, liver, red and white muscles of males and females at different stages of gonad's maturity (V and VI stages). The peculiarities of AO complex and LP depended on tissue specificity and sexual distinctions of the turbot have been found. The turbot females at VI stage were found to have the most significant changes. In gonads and liver the level of TBA-reactive products decreased. In gonads the activities of GP and GR decreased, but the level of GSH increased. In gills of these females the activity of GP and the level of GSH increased, while in the red muscles the activity of catalase raised. In white muscles the activity of GR dropped. In the males' tissues of the turbot at VI stage the growth of the activity of GP in gills and GSH content in white muscles have been found. In all tissues of males the decrease of the TBA-reactive products content has been observed.     

Size of the fibrillar centres of the nucleoli in the supraoptic nucleus of the rat taking the Swiss cheese effect into account

The size of the fibrillar centres (FC) in nucleoli was investigated taking the Swiss cheese effect into account. Electron microscopy was performed on the neurons of the rat supraoptic nucleus after the secretion of vasopressin had been fully suppressed by water load, after the secretion had been stimulated by water deprival and in normal rats with water ad libitum. When the secretory activity was suppressed from a normal level to approximately no activity, the size of the individual FC was doubled. Moreover, with increasing secretory activity the number of FC per cell increased.     

The action of the venom of the spider Eresus niger on the neuromuscular synapses of the frog

The effect of Eresus niger spider venom on frog neuromuscular preparations has been studied using the intracellular microelectrodes. The spider venom has been found to block both spontaneous and elicited transmitter release and possesses the phospholipase activity. It has been suggested that the venom blocking synaptic transmission results from its phospholipase activity by analogy with the action of snake presynaptic neurotoxins.     

Amelioration by menadione of the experimental chronic immune arthritis in the rabbit

The immunological induction of arthritis in the knee of the rabbit is well established as a model for human rheumatoid arthritis. It has the special advantage of allowing the development of the condition, and the effect of disease-modifying agents, to be followed. Attention has been focussed on the activity of glucose 6-phosphate dehydrogenase in the synovial lining cells since the fourfold elevation of this activity was shown to be fundamental in the human condition. An equal elevation of this activity has now been demonstrated in the rabbit model. Furthermore, it has been shown that the oral administration of menadione decreases this activity towards normality with a concomitant decrease in the degree of inflammation.     

Iron-containing proteins and the proteolytic activity in the blood serum in hyperbaric oxygenation and the protective action of urea

The number and composition of ferro-containing proteins, the total number of iron, summary peroxidase activity and peptide-hydrolase activity have been determined under different hyperbaro-oxygenation (HBO) in blood serum. It has been established that under HBO the concentration of ferro-containing proteins increases, the fraction composition of serum and erythrocyte haemoglobin changes, the activity of acid peptide-hydrolases increases and the protamine-splitting peptide-hydrolase activity lowers. The administration of urea before HBO-experiments leads to the normalization of the most biochemical indicators of blood serum. The tests of oxygen intoxication depth assessment have been suggested.     

Effect of Green and White Flashes on the Activity of the Enzyme Ribulose-diphonphate Carboxylase in Darkgrown Barley Plants

The effect of short impulses of white and green light on the activity of ribulosediphosphate carboxylase in dark-grown barley leaves has been studied Intermittent white light induces an increase in the activity of the enzyme. After 90 flashes a 30% increase in the activity is observed. Intermittent green light has no effect on the activity of the enzyme. A correlation between the increase in the activity of the enzyme and the accumulation of chlorophyll under the effect of intermittent white light has been observed.     

Dependence of the specific activity of antitetanus immunoglobulin on the degree of its fragmentation

Antitetanus immunoglobulin preparations with the increasing content of Fab-fragments (15, 30, 53%) have been obtained under specific experimental conditions. Tests for specific activity have revealed an insignificant decrease (13%) in this activity in the preparation containing 15% of Fab-fragments and its sharp drop in the preparations containing 30-50% of Fab-fragments. The specific activity of antitetanus immunoglobulin has been found to be related to the degree of its fragmentation.     

The beta-adrenergic regulation of the Na, K-ATPase activity in the sarcolemma of the heart muscle

Using a sensitive potentiometric method the effect of isoproterenol upon the activity of Na, K-ATPase in cardiomyocytes has been studied. The activity of the enzyme in rat sarcolemma at isoproterenol-induced myocarditis decreases by 42%. A direct action of isoproterenol on the Na, K-ATPase activity in sarcolemma in vitro has been investigated. In the concentration range 10(-9)-10(-3) M (from receptor-binding up to cardiotoxic) a gradual decrease of the activity reaching the complete inhibition at 10(-3) M is revealed. Antagonist of beta-adrenoreceptors propranolol in concentrations required for displacing the agonist (10(-9) M) provides for the recovery of the Na, K-ATPase activity up to 76% of its normal activity. This action transforms into nonspecific inhibition at rising concentration of the antagonist. Possible mechanisms of the beta-adrenergic regulation effect in cardiomyocytes on Na, K-ATPase of the sarcolemma are discussed.     

Lysosomal proteinase activity and the the lysosomes of the small intestine in postnatal ontogeny

It has been shown that in postnatal animals, the activity of lysosomal proteinases in the distal part of the small intestine was considerably higher than in the proximal one. With transition from milk to definitive nutrition, the activity of lysosomal proteinases gets equalized in the proximal and distal parts of the small intestine. The data concerning the proximo-distal gradient of distribution of the activity of lysosomal proteinases have been supported. Transition from milk to definitive nutrition has given rise to ultrastructural alterations in the lysosomal apparatus.     

Effect of vasopressin and enkephalin analogs on the chemoreactive properties of the sensorimotor cortex neurons in rats

On immobile rats it has been shown that subcuteneous injection of two different neuropeptides causes different distribution of activating, inhibiting and areactive cells resulting from microionoforetically administrated acetylcholine and noradrenaline without altering the mean frequency of the background unit activity sensorimotor cortical neurons. At the same time the alteration in the pattern of neurons impulse activity has been revealed, which acquires the character of packet activity with a specific packet length of 2-3, 4-6, 7-10 impulses. Depending on the injected neuropeptide reliable but almost contrary effects of the packet activity alterations have been observed. These effects have been suggested to result from the alteration of the chemoreactive properties of the neuron membranes and the corresponding reorganisations of interneuron attitudes.     

Dependence of the blood plasma activity of the diabetogenic factor in animals on the functional depression of the anticoagulating system induced by an atherogenic diet

It has been found that in blood plasma of rats keeping on an atherogenic diet for a long time the diabetogenic factor activity appears. The direct dependence between the level of the diabetogenic factor activity and the degree of the anticoagulating system depression caused by long keeping of the animals on the atherogenic diet has been revealed.     

Effect of acetylcholine on the cerebral microsomal Na, K-ATPase of rats of different ages

Na, K- and Mg-ATPase activity of the cerebral cortex microsomal fraction has been studied and compared in adult and old rats. The activity of Na, K-ATPase decreases while that of Mg-ATPase increases with age. The total ATPase activity remains unchanged. The effect of acetylcholine on ATPase activity has been found to be age-dependent.     

The role of the antilysozyme activity of Shigella flexneri as a factor controlling the degree of its resistance to the lytic action of bacteriophages

The level of the antilysozyme activity of S. flexneri in ensuring the high level of their phage resistance has been studied. The realization of the phage protective effect of antilysozyme activity has been noted to occur due to disturbances in the lysis of infected bacteria by phage-synthetized lysozyme-like enzyme. The direct relationship between the level of the lysozyme production of bacteriophages and their capacity for overcoming the antilysozyme protection of the host bacterium has been shown.     

Effect of light in the control of growth by auxin and its inhibitor(s) in the sunflower

Diffusates from the hypocotyl and leaves of sunflower seedlings ( Helianthus annuus L. cv. Mammoth) contain both auxin and inhibitor(s) of auxin-induced growth. The auxin activity has been evaluated with the conventional Avena coleoptile bioassay employing negative curvature, The inhibitor activity has been determined with a newly developed bioassay, measuring the positive curvature response of the Avena coleoptile. This bioassay has been standardized by the response to 2,3,5-triiodo-benzoic acid. Diffusates from plants in darkness have higher auxin activity and lower inhibitor activity than diffusates from plants in light. Irradiation at 730 nm promotes auxin synthesis in leaves, and! irradiation at 660 nm promotes synthesis of the inhibitor.