The effect of biota on global climate

A model consisting of two blocks (equations) was proposed for the analytical study of the biosphere-climate system over great periods of time. The first equation describes the balance of carbon dioxide in the atmosphere and represents the biological block of the model. The second equation is the equation of the energy balance or the physical block of the system. The model is based on the most general conceptions of living matter and the evolution process. A possible interpretation of some events and phenomena in the earth history in terms of the model is given.     

Slowing of proton transport processes in the structure of bacterial reaction centers and bacteriorhodopsin in the presence of dipyridamole

Dipyridamole, 2,6-bis(diethanolamino)-4,8-dipiperidinopyrimido(5, 4-d)pyrimidine, is employed in clinical practice as a vasodilator. It can also inhibit a specific membrane protein (glycoprotein P) which pumps anticancer drugs out of tumor cells. Dipyridamole (10-4 M) markedly slows down the kinetics of the electrogenic phase of the photoelectric response in Rhodobacter sphaeroides chromatophores. This phase is due to proton transfer from the external medium to the secondary quinone acceptor in the reaction center. In purple membranes of bacterium Halobacterium salinarium containing bacteriorhodopsin dipyridamole (in its charged state) significantly slowed the kinetics of proton transfer from the primary donor, Asp-96 (in membranes from bacteria of wild type), or from the external medium (in D96N mutant) to the Schiff base. It is suggested that dipyridamole can influence the structural-dynamic state of membrane proteins including modification of the structure of their hydrogen bonds involved in proton-transport processes.     

Catalytic antibodies (abzymes) induced by stable transition-state analogs

This review deals with recent advances in the generation of catalytic antibodies by the immunization of animals with stable transition-state analogs. Characteristic features in the functioning of such abzymes are considered in comparison with traditional enzymes.     

Effect of age and radiation exposure on the frequency of translocations and dicentrics detected by FISH method in human lymphocytes

The frequencies of translocations and dicentrics detected by "chromosome painting" in lymphocytes were estimated in 115 healthy donors and in 273 people exposed to uncontrolled irradiation at low doses 1-4 years ago. Age responses of both types of exchanges at the age range from 3 to 85 years fit to quadratic model. The frequency of translocations grew faster with age than the frequency of dicentrics. The yields of stable exchanges in exposed people was significantly higher than those in control donors of corresponding ages.     

Measurement of visual acuity and crowding effect in 3–9-year-old children

Visual acuity was measured in 140 3–9-year-old children using Landolt’s rins with a gap in one of four orientations. The influence of surrounding additional contours on the detection of orientation of rings of a minimal visible size was studied in the same children, depending on the distance between the rings and the surrounding. The latter consisted of four bands, located symmetrically with reference to the ring. Visual acuity increased with age, reaching the adult level by approximately seven years. A deterioration of the orientation recognition was detected in all children when the surrounding was close to a ring. The distance that caused a perception deterioration decreased with age, reaching the adult level by nine years. The obtained data are discussed from the viewpoint of a possible influence of individual visual areas formed during ontogeny on task performance.     

Characteristics of bunyavirus- and togavirus-induced nonspecific suppressors inhibiting delayed hypersensitivity

Some properties and mechanisms of action of nonspecific suppressor cells, inhibiting delayed hypersensitivity to sheep red blood cells and activated in vivo in experimental tick-borne encephalitis and Tahyna virus infections in mice, have been studied. These nonspecific suppressor cells have been identified as T-lymphocytes in experiments with the use of antisera to T- and B-lymphocytes. The function of the suppressor cells can be realized without their proliferation and is mediated by a soluble factor whose formation requires the synthesis of protein. In respect to hydrocortisone, the above-mentioned suppressor cells are subdivided into 2 subpopulations: hydrocortisone-resistant in the thymus and hydrocortisone-sensitive in the spleen.     

Geographic mode of speciation in a mountain specialist Avian family endemic to the Palearctic

Mountains host greater avian diversity than lowlands at the same latitude due to their greater diversity of habitats stratified along an elevation gradient. Here we test whether this greater ecological heterogeneity promotes sympatric speciation. We selected accentors (Prunellidae), an avian family associated with mountains of the Palearctic, as a model system. Accentors differ in their habitat/elevation preferences and south‐central Siberia and Himalayan regions each host 6 of the 13 species in the family. We used sequences of the mtDNA ND2 gene and the intron 9 of the Z chromosome specific ACO1 gene to reconstruct a complete species‐level phylogeny of Prunellidae. The tree based on joint analysis of both loci was used to reconstruct the family's biogeographic history and to date the diversification events. We also analyzed the relationship between the node age and sympatry, to determine the geographic mode of speciation in Prunellidae. Our data suggest a Miocene origin of Prunellidae in the Himalayan region. The major division between alpine species (subgenus Laiscopus) and species associated with shrubs (subgenus Prunella) and initial diversification events within the latter happened within the Himalayan region in the Miocene and Pliocene. Accentors colonized other parts of the Palearctic during the Pliocene‐Pleistocene transition. This spread across the Palearctic resulted in rapid diversification of accentors. With only a single exception dating to 0.91 Ma, lineages younger than 1.5 Ma are allopatric. In contrast, sympatry values for older nodes are >0. There was no relationship between node age and range symmetry. Allopatric speciation (not to include peripatric) is the predominant geographic mode of speciation in Prunellidae despite the favorable conditions for ecological diversification in the mountains and range overlaps among species.     

Method for determining kallikrein of tissue origin in blood plasma and its clinical significance

Based on a study of the kininogenase activity of the total plasma kallikrein in the presence of 3 concentrations of the soybean inhibitor trypsin (0.5, 1.0, 10.0 micrograms/ml) one can measure at a time the activity of tissue kallikrein (without specifying the source) and the activity of 3 forms of plasma kallikrein, including its adsorption on kaolin that characterizes the conformational structure of the enzyme. Examination of 10 healthy subjects and 136 patients revealed a 10 to 20-fold increase in the content of tissue kallikrein in plasma of 70% of diabetes mellitus patients and a 2.5 to 3-fold elevation in 50% of patients with chronic occupational bronchitis, and in 30% of patients suffering from chronic hepatitis. The method suggested makes it possible to have a better insight into the physiological and pathogenetic role of the kinin system and may be used for laboratory control over the treatment efficacy.