[Effect of moxonidine on the cardiac chronotropic regulation in hypertensive rats SHR-SP]. / Vliianie moksonidina na kardiokhronotropnye mekhanizmy reguliatsii u gipertenzivnykh krys SHR-SP.

The administration of moxonidine for two weeks in a daily dose of 2 or 10 mg/kg (p.o.) reduced the cardiac sympathetic tone in stroke-prone spontaneously hypertensive rats (SHR-SP) by 24.3 +/- 7.3 and 32.2 +/- 10.2%, respectively. In addition, the treatment influenced the cardiac baroreflex by decreasing the bradycardic plateau and increasing both bradycardic and tachycardic range. The baroreflex gain increased in a dose-dependent manner by 41.6 +/- 12.1 and 103.0 +/- 3.9%, respectively. These data indicate that moxonidine can modulate the cardiac autonomic (tonic and reflex) chronotropic control.

[Effects of chronic administration of moxonidine in hypertensive rats SHR-SP]. / Effekty khronicheskogo vvedeniia moksonidina u gipertenzivnykh krys SHR-SP.

Study of the hemodynamic response (arterial pressure and heart rate) by radio- and telemetric techniques in stroke-prone hypertensive rats (SHR-SP) aged 6-7 months showed that a chronic oral administration of moxonidine at a daily dose of 2 and 10 mg/kg) leads to hypotension (7 +/- 3 and 21 +/- 5%, respectively) and bradycardia (5 +/- 1 and 14 +/- 5%, respectively). The moxonidine administration at a greater dose violated the circadian heart rate profile, reduced the motor activity of rats by 34 +/- 15%, and showed a drug dependence syndrome in the heart rate (but not in the arterial pressure). It is concluded that moxonidine administration at large doses may give rise to side effects.

[Effect of preservation conditions on the viability and activity of Streptomyces griseus--producer of the antibiotic grizin]. / Vliianie uslovii khraneniia na zhiznesposobnost' i aktivnost' Streptomyces griseus--produtsenta antibiotika grizina.

Strain AURIGenetics- 1552 of Str. griseus producing grisin used as a feed additive was obtained in the course of stepped selection. It is deposited at the Central Collection of Industrial Microorganisms of the USSR and designated as strain S-248. The strain was stored under varying conditions and their effect on its viability, morphological variation and antibiotic potency was studied. Investigation of the strain variation with respect to the cultural and morphological properties and the antibiotic production revealed definite correlation between the morphological properties of the culture and its capacity for the synthesis of the antibiotic. The medium G-1 containing KNO3 as the only source of nitrogen was found to be advantageous for maintaining the strain potency on storage with the method of subcultures or under a layer of mineral oil. It was shown that the strain can be successfully stored by lyophilization. This method in combination with selection of active variants from populations of lyophilized cells provided not only maintenance of the culture potency at the required level but also its increase.

[Spontaneous L-transformation in actinomycetes]. / O spontannoi L-transformatsii u aktinomitsetov.

Spontaneous L-transformation was described in Actinomadura and Nocardiopsis. Cultures growing for two days were found to contain polymorphous cells (0.5 to 1.5 mum) lacking a cell wall. A considerable portion of the cell is occupied with a nucleoid while the cytoplasm is forced toward the periphery of the cell. Membranous structures formed by five-layer membranes can be seen in the cytoplasm. Budding has been observed. The above features are typical of bacterial L-forms and has not been found in cells with an intact cell wall.

[Utilization of a method of growing microorganisms on millipore filters in order to study their structure with a scanning electron microscope]. / Primenenie metoda vyrashchivaniia mikroorganizmov na milliporovykh fil'trakh dlia izucheniia ikh struktury so skaniruiushchim élektronnym mikroskopom.

A comparative study of bacteria and their L-forms Actinomyces and blue-green algae, taken from centrifugates and grown on Millipore filters, was made with the use of scanning electron microscopy. The study revealed that only in the second case the location of the cells inside the colony was preserved and the architectonics of the colony remained unchanged. The anastomoses between the cells and slime on the cell surface, destroyed when other methods of making the preparations were used, could be easily detected.