Survival strategy of Bdellovibrio

The effects of cadmium and diuron, typical environmental pollutants, on the survival of predatory bacteria of the genus Bdellovibrio were studied. The adhesion and cohesion of bdellovibrios were shown to enhance cell resistance to xenobiotics. The viability of Bdellovibrio cells was shown to be higher at the stage of bdelloplasts. The obtained results confirm the concept of the surface-associated existence of Bdellovibrio in the natural environment and serve as a basis for the employment of predatory bacteria to solve the problems of human population health, biological protection of ecosystems, and bioterrorism protection.     

Carbonic Anhydrase of the Alkaliphilic Cyanobacterium Microcoleus chthonoplastes

The activity of carbonic anhydrase (CA) was studied in different cell fractions of the alkaliphilic cyanobacterium Microcoleus chthonoplastes. The activity of this enzyme was found in the soluble and membrane protein fractions, as well as in intact cells and in a thick glycocalyx layer enclosing the cyanobacterium cells. The localization of CA in glycocalyx of M. chthonoplastes was shown by western blot analysis and by immunoelectron microscopy studies with antibodies to the thylakoid CA from Chlamydomonas reinhardtii (Cah3). At least one of the CA forms occurring in M. chthonoplastes CA was shown to be an -type enzyme. A possible mechanism of the involvement of the glycocalyx CA in calcification of cyanobacteria is discussed.     

The thylakoid carbonic anhydrase associated with photosystem II is the component of inorganic carbon accumulating system in cells of halo- and alkaliphilic cyanobacterium Rhabdoderma lineare

The organization of carbonic anhydrase (CA) system in halo- and alkaliphilic cyanobacterium Rhabdoderma lineare was studied by Western blot analysis and immunocytochemical electron microscopy. The presence of putative extracellular alpha-CA of 60 kDa in the glycocalyx, forming a tight sheath around the cell, and of two intracellular beta-CA is reported. We show for the first time that the beta-CA of 60 kDa is expressed constitutively and associated with polypeptides of photosystem II (beta-CA-PS II). Another soluble beta-CA of 25 kDa was induced in low-bicarbonate medium. Induction of synthesis of the latter beta-CA was accompanied by an increase in the intracellular pool of inorganic carbon, which suggests an important role of this enzyme in the functioning of a CO(2)-concentrating mechanism.     

External forcing factor reflected in the common signals of δ18O-tree-ring series of Larix sibirica Ledeb. in the Lake Baikal region

A set of δ¹⁸O-tree-ring series obtained from larch trees growing in three different ecotopes near Lake Baikal are analysed together with the relevant meteorological data. It has recently been proposed that the external forcing factor, as a characteristic of the total investigated territory, must cause a certain similarity of the essential properties of the simple processes induced by this forcing. The similarity is the main point of this investigation and is the basis for a constructive definition of the intersection of the sets of these induced processes as data sets. We specify the elements of the intersection of the sets as the “common signals” for each process (set). The common signals are computed by a new algorithm of “co-filtering”, which is based on the trigonometric Fourier transform. We call the output of this algorithm the “co-filtered common signals” (CCS).We discovered that the CCS gave substantial contributions to the variances of the initial isotope series, which are more weakly correlated than their CCS. Next, we found that synchronous variations of the CCS of the temperature and precipitation for April–May and June–August induce synchronous variations in the CCS of the δ¹⁸O-tree-ring series. Furthermore, the characteristics of such synchronism vary with time.We concluded that the CCS of the δ¹⁸O-tree-ring series clearly express the external forcing factor even when there are significant differences in the vegetation conditions.     

Effect of individual chromosomes on sex behavior of Drosophila

Dependence of intensity of Drosophila virilis male sexual behaviour on age-related differences was studied. Most active proved to be those age periods which correlated with the time of S-esterase elevated activity. Courtship displays were compared in strains 101 and 160, interstrain differences correlating with the S-esterase activity level. As S-esterase plays an important role in fertilization, this relationship seems to be non-random. It is quite possible that the level of S-esterase activity regulates male sexual activity in natural populations. Some variations in male courtship display in interspecies hybrids (D. virilis x D. littoralis) were demonstrated which depended on the gene dose of respective species. It may well be that in the bk and dt gene regions those genes are localized which are responsible for courtship behaviour. The analysis of sexual behaviour in interstrain and interspecies hybrids proved to be successful approach to elucidating possible role of separate chromosomes in sexual behaviour determination.     

Mechanisms of the different effect of sucrose on the quantity of lipids in the blood and liver of experimental animals]

Experiments on rats showed that inclusion of sucrose into the composition of diets with increased or normal carbohydrate content accelerated the synthesis in the liver of apoproteins of pre-beta-lipoproteins and their loading with endogenously formed lipids, promoted a more intensive secretion of lipoproteins of very low density into the blood and an increase in it of the triglyceride level. However, the rate of the lipid compensation with the protein of pre-beta-lipoproteins in the liver depends also on the qualitative ratio of the carbohydrate and fat components in the diet. In using the diet with sucrose with the physiological ratio of carbohydrates and fats (2:1) there was noted a lower load of apoproteins of pre-beta-lipoproteins with lipids, this leading to an increase of the latter in the liver.