Action of various surface-active substances on the genetic transmission of R-plasmids in E. coli]

The effect of 4 groups of surface active-substances (SAS) on conjugation and transduction transfer of plasmid RIdrd from the donor of E. coli J 5-3 to the recipient of E. coli C600 was studied. It was shown that the anionic SAS (8 compounds) had the highest inhibitory effect. They completely inhibited both the conjugation and the transduction transfer of R-plasmids. The amphoteric SAS, i. e. tego-51 and ampholan had the same effect only on the transduction R-transfer. The conjugation R-transfer was inhibited by the above compounds to a significant extent but not completely, i. e. by 70.8 and 361.9 times respectively. The effect of the non-ionogenic preparations, i. e. sintanol DT-7 was even less (the inhibition coefficients of 54.8 and 22.8 on conjuction and transduction respectively). The cationic SAS, i. e. catamine AB and HIPC-200 had no effect on the genetic R-transfer. It was shown that the anionic SAS had a phagocytic effect on phage Plks. It is of interest to note that the anionic SAS, i. e. sintanol NP-3 effectively suppressed the conjugation transfer even in a concentration of 100 gamma/ml which was 1000 times lower than the subbacteriostatic one. The effectiveness of the anionic SAS did not depend on the length of the dydrocarbon chain and was the same in separate homologues and their mixtures. The high inhibitory activity of most of the SAS and especially the anionic ones with respect to both the conjugation and the transduction R-transfer was of interest.     

The influence of glucocorticoids and catecholamines on the neuromuscular transmission

The review surveys the impact of “stress hormones”–glucocorticoids and catecholamines–on the functioning of the neuromuscular synapse. The review brings together the data on the influence of the main agents of stress–cortisol and norepinephrine–on the intensity and timing of the acetylcholine release, as well as signaling effect of its co-mediator ATP.     

Increase in tetracycline activity by using surface-active substances]

The antimicrobial effect of cationic and anionic surface-active substances, i.e. catamine AB and sulphonol NP-3 respectively was studied in vitro with respect to gramnegative bacteria. In non-bactericidal concentrations catamine AB significantly increased the efficacy of tetracyclines, while the anionic compound had no such effect. The increase in the tetracycline activity was due to the antibiotic increased absorption (14C-oxytetracycline as an example) on the treatment of gramnegative bacteria with catamine AB and staphylococci with catamine AB and sulphonol NP-3, which was mainly associated with impairement of the cell membrane permeability by the surface-active substances.     

An evaluation of the genotoxicity of nonionogenic surface-active substances]

The mutagenic activity of 16 industrial nonionic surfactant samples has been investigated in Ames-test without metabolic activation and with the use of mouse liver microsomal fraction in vitro. The genotoxical estimation of their possible biodegradation products is given. The mutagenicity of a number of high molecular polyethylene glycoles related to nonionic surfactants is shown.     

Effect of inhalation of surface-active substances on the surfactant system of the lung]

Surface activity, biochemical composition and morphology of the rat lungs were studied in norm, under effect of acute hypoxia and after infusion of obsidan (1 mg/100g). The data permit suggesting that under the influence of obsidan and hypoxia a stability index of surfactants and quantity of phospholipids decreased, while the quantity of lysophosphatidylcholine and lysophosphatidylethanolamine increased. Morphology studies show that after hypoxia and obsidan infusion oedema and cell destruction developed in the lung. The inhalation of exogenous surfactant increased stability index and quantity of phospholipids, decreased the quantity of lysophospholipids but did not eliminate morphological disorders in the lung induced by hypoxia and obsidan infusion.     

Presynaptic mechanisms of zinc effects on the neuromuscular transmission]

The effect of zinc ions on presynaptic currents and transmitter release was studied at the neuromuscular junction of the frog cutaneous pectoris muscle preparation with using an extracellular microelectrode. It has been shown that zinc (100 mkM) amplified MEPP frequency at first, but suppressed it later. Zinc affected the presynaptic spike waveform and transmitter release in a concentration-dependent manner. Depending on concentration and time of exposure zinc increased or suppressed transmitter release. Increase of transmitter release was shown to be resulted by blockade voltage gated and calcium activated potassium channels in nerve ending, leading to broad of both presynaptic spike and action potential. Strong change of presynaptic spike waveform after high concentration zinc treatment supposed that under this condition zinc depressed voltage gated calcium and sodium channel leading to decrease of transmitter release. It was concluded that the final and irreversible depression of acetylcholine release by zinc was due to alteration of whole ion conductances in nerve ending and to change of configuration of proteins included in structure of ion channels. It is discussed possible mechanisms of various effects of zinc ions at the neuromuscular synapse.     

The effect of neutotropic substances on motor excitation in dogs induced by amizil]

The motor activity of dogs was quantitatively recorded before and after the intramuscular injection of amizyl (2 mg/kg). Amizyl was found to induce hyperactivity for 2-3 hours. Galanthamine (3 mg/kg) blocked the effect of amizyl. Etaperazine was the most active substance of the neuroleptic tranquillizers tested. Chlorpromazine and diazepam deranged the dogs' state. Diazepam and haloperidol potentiated the effect of amizyl. Motor hyperactivity induced by amizyl is supposed to be connected with anticholinergic mechanisms; no neuroleptics with cholinolytic properties should be used for the treatment of amizyl intoxication.     

Effect of leucine-enkephalin on the interneuronal transmission of excitation]

In the experiments on non-anesthetized flaxedil-immobilized cats it has been shown that the injection of leucin-enkephalin (1 mg) into the lateral ventricle of the brain is followed by the inhibition of evoked potentials in the ventrolateral columns of the spinal cord and of segmental interneuronal transmission in the spinal cord as well as by the reduction of the amplitude of potentials in the S I zone of the brain cortex induced by the sciatic nerve stimulation. Naloxone (1 mg/kg, i.v.) prevented the effects of leucin-enkephalin. Methysergide pretreatment (2.5 mg/kg, i.p.) led to a decrease of leucin-enkephalin effect on the interneuronal transmission in the spinal cord. Leucin-enkephalin failed to change the amplitude of polysynaptic potentials of glosso-mandibular reflex integrated at the brain stem level.     

Effect of surface-active substances on bioluminescence intensity of bacteria

The study of sensitivity of luminous bacteria isolated from the Black and Azov seas to surfactants from various classes was carried out. It was shown that cationic surfactants had a strong inhibition effect on bacterial luminescence in contrast to anionic and in particular nonionic surfactants. To increase the luminous bacteria sensitivity to the action of OP-10 (nonionic surfactant) and ABS (anionic surfactant), which are widely used in industry, several approaches have been developed. They include modulation of bacterial sensitivity by the additives of cationic substances, use of luminous bacteria at a logarithmic stage of growth, realization of biotesting at low pH = 5.5. The use of these approaches allows to lower effective concentrations of OP-10 and ABS, which caused a decrease of bioluminescence by 50%, 3-200 times and opens perspectives for the use of the bioluminescent method to study these surfactants toxicity on the principle of biosensorics.     

The effects of heptaminol chlorhydrate on neuromuscular transmission

6-Amino-2-methyl-2-heptanol chlorhydrate, heptaminol chlorhydrate, blocks the response to indirect stimulation of the mouse diaphragm in vitro. This effect is due to a dose-dependent pre- and post-synaptic block of neuromuscular transmission starting at 1 mM heptaminol (HEPT). The complete block of neuromuscular transmission occurs at 10 mM. At 2 mM, the decrease in quantal size is more significant in the presence of d-tubocurarine than when the extracellular calcium is lowered. At this concentration, heptaminol also prolongs the depolarization time of the motor end plate potential. Slightly higher concentrations of heptaminol produce a decrease in quantal content. This latter effect is associated with an increase in synaptic delay.     

Directed screening of bacteria--destructive agents of surface-active substances

A procedure for detection of bacteria destructing cationic surface active substances (CSAS) was developed. The procedure is based on changing colour of pyrocatechin violet, an organic dye from geen-blue in the presence of a CSAS to red-brown in its absence. After application of pyrocatechin violet to bacterial macrocolonies grown on a synthetic medium with a CSAS as the only source of C red-brown zones developed around the colonies which was probably indicative of the CSAS biodestruction. 55 strains of bacteria destructing undecylpyridinium bromide, a CSAS were isolated from water of sewage purification plants. The study of their spectrum with respect to CSASs of different chemical structure revealed 6 bacterial strains capable of destructing all the nine test preparations. It was shown that biodestruction of the CSASs was associated with the long carbon chain and depended on the presence of the substitute in the aromatic ring and branching in the side chain. Therefore, the procedure provides screening of microbes destructing CSASs and may be used for rapid determination of biodestruction of CSASs with different chemical structures.     

Effect of psychotropic substances on conditioned reflexes in cats after emotional excitation]

Emotional rage and fear were found to destroy the differential inhibition and the short-term memory in cats. Stelazine, haloperidol, amitriptyline, imizine, chlordiazepoxide, diazepan and benactyzine prevented these disturbances. Chlorpromazine, as well as stelazine and haloperidol in high doses, enhanced these disturbances. The tranquillizers and the antidepressants normalized the higher nervous activity at a greater dose range than neuroleptics and were more preferable for the elimination of the negative consequences of the strong emotional reactions.     

Mutagenic and carcinogenic action of antimicrobial surface-active substances

The study on the mutagenic activity of commercial synthetic cationic, anionic, amphoteric and nonionogenic surface active substances with antimicrobial properties demonstrated that they had no mutagenic effect on the microbial test systems, i.e. the histidine-deficient strains of Salmonella typhimurium on direct contact and under conditions of metabolic activation in vitro and in vivo. The cationoactive preparation B Kh-14 with the benzyl radical adjoining the nitrogen atom and linear hydrophobic C13H27 with the amide group having a pronounced antimicrobial effect on gram-positive and gram-negative bacteria and fungi showed no carcinogenic activity in the experiments with its long-term action on the urinary bladder mucosa and skin of rats, guinea-pigs and dogs.     

Microorganisms destroying a number of nonionogenic surface-active substances

Microorganisms destroying nonionogenic surfactants (NS) were selected. The isolated cultures were assigned to the genera Pseudomonas and Bacillus. Biodestruction of 19 NS was studied in Erlenmeyer flasks with shaking and in the course of continuous cultivation. The rate of destruction was shown to depend on the chemical structure of a substance: block-copolymers of ethylene and propylene oxides were more resistant to the action of microorganisms. The results indicate that sewage waters containing NS (at an initial concentration of 50 to 500 mg/l) can be purified on local installations using microbial cultures or their complexes.