Regional graft vs host reaction to H-Y antigen (immunological mechanisms)

Structural changes in the regional popliteal lymph nodes have been studied in C57Bl/6 male mice at the peak of the reaction "graft-versus-host" to H-Y antigen. Morphological and morphometrical investigations have been carried out in three groups of males (10 animals in each group). The first group includes intact animals (the first control group). To the males of the second group (the second control group) lymphoid cells are inoculated from intact C57Bl/6 females. To the males of the third group (experimental group) lymphoid cells are inoculated from H-Y antigen immunized C57Bl/6 females (anti-H-Y effector lymphocytes). The popliteal lymph nodes of the male mice from the third group twice increase in their size comparing to those in the control (the first and the second groups). Miotic activity increases in them 4.5 times, amount of cellular blast forms in medullary cords--4 times and 10 times--in the light zone of the cortical substance. Ratio of macrophages and eosinophils in structural components of the lymph nodes studied changes; this is, evidently, connected with massive destructive progresses, that take place in the lymph nodes of the animals from the third group. The results of the morphological investigations are in agreement with the hypothesis suggested, explaining the mechanism of development of the regional reaction "graft-versus-host" to H-Y antigen, basing on idiotype-antiidiotype interaction (the idiotypic network in the immune system).     

SOS-induction of the RP4 plasmid tet-determinant

Induction of the tetracycline-resistance genes function by the inducer of the DNA-repair and mutability SOS-system, UV-light, has been tested. Activity of the tet-genes residing on the plasmid RP4 in Escherichia coli cells has been shown to be inducible by the low doses of tetracycline as well as by the mutagenic doses of UV-light. The induction was quantitatively registered by measuring the activity of beta-galactosidase of bacteriophage Mud1 (Ap, Lac) inserted into the tet-genes of the plasmid RP4. The bacteriophage integration inactivates the tet-genes function of the constructed plasmid fusing the lac-operon to a promoter of inactivated genes. Precise excision of bacteriophage restores the activity of the tet-genes proving together with the plasmid DNA-restriction analysis the fusion of tet-promoter with Iac-operon. The tet-genes of RP4 are concluded to be a part of the SOS-regulon, a set of genes inducible by the conditions harming the bacterial cell. Preliminary data on the mutagenic activity of tetracycline obtained in the bacterial test-system of mutagens are discussed.     

Effects of plasmid pKM101 on the expression of Escherichia coli and Salmonella typhimurium genes under ultraviolet irradiation

The study focused on plasmid pKM101, which is a necessary component of the short-term test of Eim's system (Salmonella-microsome test), to detect the potential carcinogens through their mutagen activity. We found a previously unknown feature of the plasmid to enhance the expression of certain plasmid and chromosome genes. The purpose of the present study was to examine and specify the role of operon mucAB responsible for the mutation properties of the plasmid in activating the expression of bacterial genes. An ultraviolet-induction examination of bacterial genes, with the mutants of plasmid pKM101 affecting operon mucAB being used, showed that the function of genes mucAB did activate, but, on the contrary, suppressed the induction of genes elt (i.e. of genes controlling the formation of LT-toxin of Escherichia coli) and of sfiA (SOS-regulated gen E. col controlling the cell division.     

Principles of organization of polistinae (Hymenoptera,Vespidae) population

The paper describes some invariant relations of the Polistinae population structure, including resistance to abiotic and biotic factors that occurs against the background of the hierarchy of biological systems and increasing autonomy of their functioning. A decrease in the dependence on the hostile environment is shown to be due to the activity of foundresses and workers adjusting to external rhythms, developing specialized responses to predators and parasites (predictable external noise of biotic nature), and creating new information. The population organization of Polistinae wasps is considered in the framework of Anokhin’s theory of functional systems and systemogenesis. There are specific processes in the population that unite individual colonies and their reproduction; they are accompanied by the formation of an advanced feedback and functional systems. Systemic processes can be simultaneously regarded as “adaptation” (reflecting the organization of environmental elements) and as “adaptiveness” (reflecting the organization of the activity of intra-colony processes and the organization of reproduction). The organization of the colony activity and reproduction in functional systems reflects the future survival rather than the preceding phenomena and events. The behavior of individuals in a colony is determined not only by the effects of abiotic and biotic factors (via transformation of cues into behavioral programs), but also by previous adaptations (stored in the “memory” as images of still absent events). General progress, limited or partial progress, and narrow specialization in the organization of polistine colonies and populations are considered using the examples of morphofunctional, environmental, energy and information criteria. The emphasis on invariant relations makes it possible to more fully describe biological systems in terms of such general categories as isomorphism, homeostasis or self-organization, and also enables us to use more effectively the theory of general functional systems in studying social insects.     

Antioxidant activity of vegetable oils with different omega-6/omega-3 fatty acids ratio

The antioxidant activity and the oxidative stability of flax, sesame, silybum oils and seed blend oils with different ω-6/ω-3 fatty acid ratios have been investigated. The antioxidant content (AO) in crude oils and their reactivity towards peroxyl radicals were studied using the kinetic method based on oil addition to the model reaction of cumene oxidation. There were correlations between the ratio polyunsaturated fatty acids (PUFA)/ω-9 and thermal stability (50°C); between the effect of γ-tocopherol content and oil resistance to oxidative changes during long-term storage at (10 ± 2)°C.     

Cytological structure of the lymph nodes after administration of foreign protein]

Changes in the cellular compositon of popliteal lymphatic nodes of albino rats were studied in normality and after injection of a foreign protein. Allergic inflammation was caused by injection of 0,25 ml of the horse serum. Observations were made on the 1, 3, 8, 19 and 30 days after the beginning of experiment. The cellular composition was counted in 30 visual fileds in the cortical plateu, follicles and myelinated cords. The average percentage of cellular elements has been determined. It has been shown that the reticular cells have less changes as compared with other cells in response to antigen stimulation. An inverse correlative relationship was noted between small and medium-sized lymphocytes. The greatest percentage of plasmic cells was noted in myelinated cords; in the follicles they are found as solitary units. In the primary immunization the cellular composition of follicles was little changed as compared with the cellular composition of the cortical and medullary substance. The cellular reaction was most pronounced in myelinated cords. Thus, the investigation of the cellular composition of different structure components of the rat's lymphatic nodes after injection of the foreign protein has revealed a different degree of their reaction.     

Mating system in a population of the wasp <Emphasis Type="Italic">Polistes dominulus</Emphasis> (Christ) (Hymenoptera,Vespidae)

The specific features of mating females and males of different morphs collected from a population of the wasp P. dominulus in Southern Ukraine were studied. Data analysis of mating individuals in experiments indicated a random mate choice by size and assortative mating by coloration. The most actively copulating males in the experiments had light-colored mesopleuron, sternite, and fore and middle coxae. They were similar in the color pattern and size to resident males, which defend their territories in the habitat. Most P. dominulus females mated only once. In their coloration, those females represented the majority of the individuals in the population. The color variability of the foundresses was shown to change in a cyclic pattern. The possibility that such variability may result from selective or assortative mating is discussed. The color and pattern traits of P. dominulus females and males could serve as markers of their reproductive strategies and their reproductive success on the whole.     

Exogenous treatment with salicylic acid attenuates cadmium toxicity in pea seedlings

The present study investigated the possible mediatory role of salicylic acid (SA) in protecting plants from cadmium (Cd) toxicity. The exposure of pea plants to increasing Cd concentrations (0.5, 1.0, 2.0 and 5.0 μM) during early stages of their establishment, caused a gradual decrease in shoot and root fresh weight accumulation, the rate of CO₂ fixation and the activity of ribulose-1,5-bisphosphate carboxylase (RuBPC, E.C. 4.1.1.39), the effect being most expressed at higher Cd concentrations. In vivo the excess of Cd-induced alterations in the redox cycling of oxygen-evolving centers and the assimilatory capacity of the pea leaves as revealed by changes in thermoluminescence emission after flash illumination. The levels of some important parameters associated with oxidative stress, namely lipid peroxidation, electrolyte leakage and proline production were increased. Seed pretreatment with SA alleviated the negative effect of Cd on growth, photosynthesis, carboxylation reactions, thermoluminescence characteristics and chlorophyll content, and led to decrease in oxidative injuries caused by Cd. The data suggest that the beneficial effect of SA during an earlier growth period could be related to avoidance of cumulative damage upon exposure to cadmium thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. In addition, the observed high endogenous levels of SA after treatment with Cd suggests that SA may act directly as an antioxidant to scavenge the reactive oxygen species and/or indirectly modulate redox balance through activation of antioxidant responses.Taken together these evidences could explain at some extend the protective role of SA on photochemical activity of chloroplast membranes and photosynthetic carboxylation reactions in Cd-stressed pea plants.     

Salicylic acid and photosynthesis: signalling and effects

Salicylic acid (SA) is a well-known signalling molecule playing a role in local and systemic acquired resistance against pathogens as well as in acclimation to certain abiotic stressors. As a stress-related signalling compound, it may directly or indirectly affect various physiological processes, including photosynthesis. The effects of exogenously applied SA on plant physiological processes under optimal environmental conditions are controversial. Several studies suggest that SA may have a positive effect on germination or plant growth in various plant species. However, SA may also act as a stress factor, having a negative influence on various physiological processes. Its mode of action depends greatly on several factors, such as the plant species, the environmental conditions (light, temperature, etc.) and the concentration. Exogenous SA may also alleviate the damaging effects of various stress factors, and this protection may also be manifested as higher photosynthetic capacity. Unfavourable environmental conditions have also been shown to increase the endogenous SA level in plants. Recent results strongly suggest that controlled SA levels are important in plants for optimal photosynthetic performance and for acclimation to changing environmental stimuli. The present review discusses the effects of exogenous and endogenous SA on the photosynthetic processes under optimal and stress conditions.