Том 54, № 4 (2018)

Type 1 and type 2 diabetes mellitus (DM) are known to increase the incidence of thyroid gland (TG) dysfunctions. The review addresses the literature data and our experimental results on the molecular mechanisms that underlie thyroid disorders under DM. Most important of these mechanisms are the attenuation of thyrocyte adenylyl cyclase signaling system sensitivity to thyroid-stimulating hormone, the decrease in the number of thyroid hormone receptors in peripheral tissues, and the decline in activity as well as changes in the ratio of different deiodinase forms in these tissues. Decreased activity of D2 deiodinases, which convert thyroxine into the active form of triiodothyronine, is associated with the development of insulin resistance, while decreased activity of D3 deiodinases, which catalyze inactivation of triiodothyronine in pancreatic β cells, suppresses insulin secretion and leads to insulin deficiency. Thus, both the excess and the deficiency of thyroid hormones can entail diabetic pathology. Identification of thyroid disorders is of utmost importance for elaborating novel approaches to treat and prevent thyroid diseases associated with type 1 and type 2 DM.

We report here the outcomes of studies on the total carotenoid composition in tissues of sexually mature and immature bivalves A. kagoshimensis. Gonadal maturation was found to be accompanied by a redistribution of total carotenoids across the body. In the prespawn period, a highest level of total carotenoids (TC) was detected in the gonads (3.97 ± 1.25 mg/100 g wet weight), however, allowing for mass-dimensional tissues characteristics, the molluscan foot still accounted for a major portion of TC (26 ± 3.9%). The spectra and concentrations of gonadal and total nongonadal carotenoids were analyzed. In all molluscan tissues, the dominant carotenoid fractions were those of pectenolon and alloxanthin, with the latter being quantitatively inferior to pectenolon in generative tissue.

We analyze here for the first time the plasma free amino acid profile in pond bats (Myotis dasycneme Boie, 1825) living in the boreal Ural region and exposed experimentally to low positive and near-zero temperatures during their preparation for hibernation. Pond bats were caught in their mass habitation territory in the Middle Ural near the Smolinsky cave (N 56°28’, E 61°37’) in the third decade of September 2015. Qualitatively, blood plasma in pond bats contains 21 amino acids. In a model experiment carried out on pre-hibernating animals at a regular hibernation temperature (0–2°C), the total plasma pool of free amino acids increased significantly by 42% (irrespective of sex) and reached 1561.4 ± 112.6 μmol/L (p = 0.01). Under these experimental conditions, the fraction of glucogenic amino acids rose by 34% (p = 0.01) and that of essential ones by 80% (p = 0.001). Both in control and experimentally cooled pre-hibernating animals, the plasma was found to lack tryptophan, suggesting its utilization as a substrate in the synthesis of serotonin, a biogenic amine directly involved in the maintenance of hypothermia and hypometabolism in these chiropterans.

Phytophagous insects and host plants have a complex of microsymbionts and make up a united co-evolving system with them. Microsymbiotic complexes are actively involved in stress responses of macrosymbionts. We established that a treatment of potato plants with endophytic bacterial strains Bacillus thuringiensis var. thuringiensis-5689, B. th. var. kurstaki-5351, and Bacillus subtilis 26D decreased the survival rate of the plant feeder, Colorado potato beetle Leptinotarsa decemlineata Say. The B. th. strains suppressed phenoloxidase and acetylcholinesterase activities in the beetle hemolymph. An antagonistic relationship was found between endophytic bacteria B. subtilis 26D and beetle symbiotic bacteria from the genera Acinetobacter and Enterobacter, with the former being able to suppress the growth of endophytic colonies. The recombinant B. subtilis strain 26D Cry, containing the B. th. var. kurstaki δ-endotoxin cry1Ia gene, combined the ability of the original B. subtilis 26D strain to suppress the development of beetle symbionts and immune responses with a production of the Cry toxin, thus leading to a high mortality of the phytophage.

The peculiarities of carbohydrate metabolism were studied in seven rat strains under conditions maximally approximating natural ones. The glucose absorption level in the small intestine was evaluated using a method based on ad libitum drinking of concentrated glucose solutions by prefasted (18–20 h) rats. It was shown that in the steady-state regime the volume-normalized uptake rate of glucose solution (mL/min) was constant and inversely proportional to the glucose concentration in the solution, while the uptake rate of glucose itself (μmol/min) was independent of the substrate concentration in quite a wide range, being mainly determined by the absorptive capacity of the small intestine. A significant difference was revealed between the tested rat strains in terms of the rate of glucose absorption from its solution (200 g/L). In the daytime (10 AM–4 PM), the highest rates were observed in Sprague Dawley rats (116.7 ± 3.1 μmol/min) while the lowest—in Wistar Kyoto rats (35.6 ± 1.1 μmol/min). In the evening (4–10 PM), rates of glucose absorption in different rat strains were 1.3–2.2 times higher than in the daytime. Apparently, the increased absorptive capacity of the small intestine in the evening is due to enhanced SGLT1-mediated active glucose transport and reflects the peculiarities of carbohydrate metabolism regulation in different rat strains.

Reactivity of the nociceptive system, psychoemotional behavior and cognitive abilities in female and male rats born to mothers that were exposed to chronic injection of fluoxetine, a serotonin reuptake inhibitor, on days 9–20 of pregnancy were studied in a battery of behavioral tests during the prepubertal period. It was found that chronic injection of physiological saline to pregnant females evoked enhanced nociceptive responses in their offspring of both sexes while fluoxetine injection neutralized the effects of such an invasive intervention, demonstrating thereby the antinociceptive effect of this agent. Negative effects of maternal fluoxetine included a weight loss in the neonate offspring of both sexes and 25-day-old males, as well as the increased anxiety level in females only as detected in the elevated plus maze test. Fluoxetine had no effect on the level of depressive-like behavior in the forced swim test in rats of both sexes. The positive prenatal effect of fluoxetine manifested itself in males as an improved spatial learning ability in the Morris water maze; the anti-nociceptive effect of chronic fluoxetine injection, as compared to the pro-nociceptive effect of chronic saline injection, can also be considered as a positive effect of fluoxetine. Sex differences in the prenatal effect of fluoxetine were revealed in the anxiety level with more anxiety behavior in females.