Zhurnal evoliutsionnoi biokhimii i fiziologii最新文献

A comparative investigation of humoral and cellular immune response in larvae of Colorado potato beetle Leptinotarsa decemlineata was conducted under development of mycoses caused by entomopatho- genic fungi Metarhizium robertsii, M. brunneum and M. pemphigi. The larvae were found highly suscep- tible to M. robertsii, M. brunneum and less susceptible to M. pemphigi. The susceptibility to the fungi was not correlated with the rate of conidia germination in epicuticular extracts of larvae. A non-specific for Colorado beetle pathogen M. pemphigi did not cause significant changes in the immune response and did not result in colonization of larvae hemocoel. Infection with M. robertsi and M. brunneum led to an increase in total hemocyte count at the initial stages of mycoses (day 2) followed by a sharp decrease on day 3. The strongest decrease was observed for the immunocompetent cells - plasmatocytes and granu- locytes. Enhanced phenoloxidase activity in hemolymph and cuticle was found on days 2 and 3 after in- fection. These changes in immune reactions correlated with the level of virulence of the strains. Thus, the immune response in Colorado potato beetle larvae is an important factor determining differences in the development of mycoses caused by different Metarhizium species.

The morphometric characteristics of immature erythroid cells in circulating blood of the round goby (Neogobius melanostomus P) were studied: late basophilic normoblasts (BN), polychromatic normoblasts (PN), normocytes (mature erythrocytes). The linear sizes of the blood cells were assessed on photographs in the computer program ImageJ 1.44p. The sizes of the longitudinal and transverse axes of the cell and of its nucleus were determined. Using the appropriate algorithm, the following parameters were calculated: form index (MS), volume (Vc), area (Sc), thickness (h) and the specific surface area (SSc) of cells and nuc- lei as well as the nuclear-plasma ratio (NCR). The major changes occurred at the stage: PN - normocy- tes. They were aimed at improving the respiratory characteristics of cells. Besides accumulating hemoglobin in the cytoplasm and suppressing the functional activity of the nucleus, a significant increase in the diffusion surface of blood corpuscles was noted. As compared to BNs, S, and SS, of normocytes increased by 40 and 17 %, respectively, and the cells became ellipse-shaped. The processes underlying the formati- on of mature erythrocyte cytoskeleton are discussed.

The brain leptin signaling system has a key role in regulation of feeding behavior, peripheral metabo- lism, functions of the nervous and endocrine systems, and disturbances in this system lead to metabolic disorders, including metabolic syndrome (MS) and type 2 diabetes mellitus (DM2). This system is activa- ted by leptin produced by adipocytes and then penetrates into brain through the blood-brain barrier, where leptin binds to leptin receptors OBRb. This leads to activation of tyrosine kinase JAK2, which phosphory- lates tyrosine-containing sites located in the cytoplasmic domain of the receptor, resulting in stimulation of activity of phosphatidylinositol-3-kinase, the transcription factors STAT3 and STAT5, phosphatase SHP2, and mitogen-activated protein kinase. Decrease in number of functionally active leptin receptors and disturbances in the downstream components of leptin cascades in neuronal cells lead to development of leptin resistance. Since the leptin system in hypothalamic neurons is closely linked to the insulin, mela- nocortin, dopaminergic and other signaling systems, leptin resistance induces a lot of functional disorders in the CNS and on the periphery. The restoration of the brain leptin system functions is one of the promi- sing approaches to treatment and prevention of metabolic disorders, including MS and DM2. The review analyzes data on structural and functional organization of the leptin signaling system, its functional, interaction with other brain signaling systems, the causes and effects of central leptin resistance, as well as the approaches to restore the functions of the hypothalamic leptin system in MS and DM2. Key words: leptin, leptin resistance, hypothalamus, JAK2-kinase, leptin receptor, diabetes mellitus, metabolic syndrome, melanocortin system, phosphatase inhibitor.

The aim of the present study was to compare effects of glucagon-like peptide-1 (GLP-1) mimetic exenatide on glucose and water-salt homeostasis in animals with different level of renal tubular proximal reabsorption - rats (Rattus norvegicus) and frogs (Rana temporaria). Following glucose tolerance test, in rats exenatide promoted rapid recovery of normoglycemia, whereas in frogs delayed this process. In water-loaded rats exenatide essentially augmented solute-free water clearance and enhanced natriuresis in furosemide-treated rats.-In frogs exenatide did not alter urinary flow rate, urinary sodium excretion and solute-free water clearance under water diuresis and furosemide treatment. It is suggested that the invol- vement of GLP- 1 in regulation of water-salt homeostasis in mammals should be preceded by key evoluti- onary transformation - increase in glomerular filtration rate and proximal tubular reabsorption.

To verify if the peptide preparation <> can be used to treat pathological processes in CNS during perinatal ontogenesis, registration and analysis of a series of physiological indicators (EMG, ECG, respiration, vagosympathetic balance) were carried out in control infant rats and in a perinatal hypoxic-is- chemic (HI) brain injury rat model. Ischemic brain injury was induced in 7-day-old rats by ligation of the left general carotid artery (under ether anesthesia) followed by keeping the animals in hypoxic gas cham- ber containing 8 % of oxygen and 92 % of nitrogen (day 1 of the experiment). One hour after the exposure to hypoxic conditions the rats of the experimental group were treated with intraperitoneal injections of cortexin at a dose of 1 mg/kg. The drug was injected daily for 10 days. Both control and non-treated ani- mals (with HI brain injury induced) were given the physiological solution. Examinations carried out on days 10 and 30 after operation revealed a lag in the body weight gain in non-treated rats as compared to control animals as well as statistically significant differences in intensity and spectral structure of EMGs between these groups. EMG of the rats.treated with cortexin showed a transient improvement of its spect- ral structure but not of the amplitude on day 10. On day 30 the positive effect of cortexin, as observed earlier, was not revealed. Respiration rate in both treated and non-treated rats was higher than in the control. Heart beat rate in operated rats was not altered, but non-treated animals on day 30 had a tendency towards its depression. The analysis of heart rate variability (HRV) showed that 10 days after trauma both treated and non-treated rats had a statistically significant shift of vagosympathetic balance towards the prevalence of parasympathetic influences. On day 30 cortexin treatment gave a positive effect whereas in non-tre- ated rats a shift of vagosympathetic balance occurred towards the prevalence of humoral, metabolic, and sympathetic influences. Administration of cortexin to intact infant rats leads to appreciable disturban- ces of vagosympathetic balance, heart rhythm, and, to a lesser extent, respiration rhythm and may cause steady disturbances of somatic and autonomic nervous system activity.

The last contractile responses (LCRN), where N is the number of individual contractile responses within tetanus, were separated from the integral tetanic responses of fast, m. Extensor digitorum longus (m. EDL), and slow, m. Soleus, rat muscles using a computer-graphic technique. The average amplitude of LCR5 in m. Soleus at a 20 Hz stimulation rate decreased to 64 ± 9 % re the amplitude of a single contraction. As N was increasing, a restoration of LCRN was observed with their subsequent rise to values almost twofold exceeding the initial single contractile responses of that muscle (up to 211 ± 10 % for LCR50). Simultaneously, against the background of rise of individual contractile responses of these muscles, a considerable shortening of their half-life time (to ≈ 50%) and formation of a stationary plateau within LCRN were observed. In m. EDL at a 50 Hz stimulation rate only single-phase rise of LCRN was observed (up to 165 ± 18% for LCR50) without change of their half-life time and plateau formation. After the end of tetanic responses in muscles of both types a prolonged (up to 30 s) "hyper-relaxation effect was shown to develop manifested as a decrease of muscle tension with its subsequent restoration to the initial values. Possible mechanisms of these effects are discussed. It is supposed that transformation of individual contractile responses in skeletal muscles may be executed at the expense of specialized microdomains in muscle fibers regulating accumulation and extrusion levels of Ca2+ ions during tetanic activity. The possible involvement of an additional, Ca(2+)-induced Ca2+ release (CICR), in the basic, depolarization-induced Ca2+ release (DICR), is analyzed.

The expression of the serotonin transport membrane protein (5-NTT) in the dorsal raphe nucleus (DNR) was investigated in laboratory Wistar rats during the early postnatal period. The results of the immunocytochemical study using primary antibodies--anti-Serotonin transporter antibody (AbCam, UK)--showed that during the first 3 postnatal weeks the intensity of 5-NTT expression in DNR of control animals changes. At the earliest postnatal times the main part of subnuclear neurons (dorsal, ventral and lateral ones) of the dorsal raphe nucleus (DNR-d, DNR-v, DNR-lat) was shown to intensely express 5-NTT. Sites of 5-NTT localization are found on the membrane surface of neuron bodies and processes in neuropile. The reduction in the number of neurons expressing 5-NTT and of its binding sites was observed on P10. At this time a redistribution of 5-NTT localization sites occurs: they are very few on neuron bodies and dendrites but are located rather densely on the plasma membrane of axons. The number of neurons expressing 5-NTT gradually increases with age and in neuropile the density of 5-NTT localization sites rises. It is shown that during the prenatal development the reduction of serotonin level in all parts of the DNR leads to a reduction in both the number of neurons expressing 5-NTT and sites of its localization in the early postnatal period, this trend continuing with age.