Biology bulletin of the Academy of Sciences of the USSR最新文献

Inhibition of adenine nucleotide transport was studied in mitochondria of winter rye (Secale cereale) seedlings. It has been shown that plant mitochondria have a translocase similar to the adenine-nucleotide translocase of animal mitochondria, since atractyloside, at a concentration of 40 micro M, inhibits Chance's State 3 respiration 100%. It has been demonstrated that palmitoyl-CoA--formed by a mitochondrial system for activation of fatty acids--lowers the rate of State 3 respiration during succinate oxidation, if palmitate, CoA and ATP are introduced into the incubation medium simultaneously. This can be explained by an inhibition of transport of adenine nucleotides through the internal mitochondrial membrane. The inhibition in question is counteracted by addition of carnitine.

Sixty subjects participated in 454 experiments, 94 of which involved a centrifuge and an overload of 2 units. The studies showed that otolithic stimulation (the 2 unit overload) either activated nystagmus or had no substantial effect on the magnitude of this property. The paper advances a new, supplementary method for individual evaluation of the functional state of the vestibular analyzer of a pilot, in complicated cases of vestibulometry in clinical examinations, by comparative evaluation of the intensity of the nystagmic response under normal and hyperbaric conditions. Patients in whom the nystagmic slow phase speed (SPS) during hyperbaria (2 units) exceeds its usual value are designated as vestibulo-resistant; persons in whom the SPS of the nystagmus does not change substantially during hyperbaria are designated as vestibulo-susceptible.

The dynamics of sleep was studied in seven healthy subjects in two schedules, differing in the magnitude of the sleep intervals and their distribution over the 24 hour period. The first series provided for the use of two four-hour sleep intervals, the second six- and two-hour intervals. The investigations showed that the transition to a new schedule was accompanied by substantial qualitative and quantitative sleep disturbances, followed by a restoration of sleep as the subjects adapted. Less pronounced sleep disorders and more rapid restoration were observed in the schedule with nonuniform distribution of the intervals; more pronounced sleep disorders and a slowed restoration of sleep were observed on the schedule with two four-hour intervals.

Antifungal activity was tested in 49 pentacyclic triterpenoids and their glycosides, of plant and semisynthetic origin. Several of these compounds inhibited the multiplication of the yeast Saccharomyces carlsbergensis. The highest antifungal activity was found in the triterpene glycosides oleanolic acid and hederagenin, which have a free carboxyl group at C 28(27). Triterpenes of the meristotropic acid, macedonic acid, and lupan types had no fungistatic activity at concentrations up to 100 microgram/ml.

For classifying life forms of plants a proposal was made to use the principle of parallel divergence based on the hypothesis that life forms diverging to any degree preserve further the potential of evolving in a similar way, that is, in parallel series. Life forms of plants are divided into thirteen types corresponding to the nature of their basic metameres. Further, every type is divided into subtypes and sections according to the character of these metameres and then into smaller grades (classification units of the system of living forms corresponding to one trait and its evolutionary level) according to categories of traits: ramification, vegetative flexibility, rate of changes of metameres, types of habitat and environment. On the basis of the principle of parallel divergence scales of traits were constructed for each category. Corresponding to 26 paires of alternative traits 26 degrees of hierarchic classification were devised and within the limits of every type of life form there were 2(26) grades at the lowest rank. Separate systems were developed for single-celled and colonial forms.

To discover the possible mechanisms determining the level of energy metabolism during changes in the body size of animals, the content of mitochondrial protein was studied in planarians during starvation and feeding. In the course of starvation, the relative content of mitochondrial protein decreases, whereas during feeding it increases. Comparison of the experimental results with previous observations on respiration of planarians under similar conditions shows that changes in the level of respiration during starvation and feeding correlate with the content of mitochondrial protein. However, the degree of the functional load on the mitochondria must be taken into account under these circumstances.

the effect of desiccation on the green alga Zygnema, a typical aquatic form of the order Conjugatae, family Zygnemaceae, is investigated. The vegetative reproduction of Zygnema occurs with the separation of the filaments in two different ways. It is shown that changes take place in cell morphology during desiccation. After division most of the cells acquire the shape of a square. These are usually half as large as the vegetative cells prior to division. Also, the form and color of the chromatophores change; they become green-brown, i.e., Zygnema falls into a state of rest, since no cell division is observed. During this state of rest the filaments suffer the unfavorable conditions of summer drought. In the fall, at the end of August, with the shortening of the day and reduction of temperature, the alga develops parthenospores for overwintering.

Over the past two decades there has arisen a new branch of biology--space biology. This short review is devoted to a discussion of its achievements. It considers the results of research in the area of gravitation biology, and an account is made of studies in those areas of radiobiology which have relevance to the study of the cosmos. There is a brief summary of the results of the search for the upper and lower limits of the biosphere, and information is presented regarding the measures employed to maintain planetary quarantine. A great deal of attention has been given to the search for extraterrestrial life, one of the most important of problems. The results obtained with the aid of the American Viking probes on Mars are given special attention. The review presents experimental data based both upon data obtained in experiments on biological specimens during space flights of satellites and space vehicles, and also upon the results of laboratory research.