


Vol 54, No 2 (2018)
- Year: 2018
- Articles: 9
- URL: https://journal-vniispk.ru/0022-0930/issue/view/9688
Comparative and Ontogenic Biochemistry
The Effect of Hypothermia on Phospholipid and Fatty Acid Composition of Synaptic Membranes in the Rat Brain
Abstract
The effect of moderate and deeper hypothermia on the phospholipid (PL) and fatty acid (FA) composition of synaptic membranes (synaptosomes) in the rat brain was investigated. As hypothermia deepened, phosphatidylcholine (PC) and phosphatidylserine (PS) levels decreased while those of phosphatidylethanolamine (PEA) remained intact. We attribute the differences both to a peculiar localization of these PL in the synaptic membrane and to a specificity of their function. Under hypothermal exposure, the saturated FA (SFA) level in the FA repertoire of total synaptosomal PL slightly decreased (by 9%) while that of polyunsaturated FA (PUFA) considerably increased, leading to a rise in the lipid unsaturation index (LUI) (by 47%) and promoting the maintenance of synaptic membrane fluidity. For three basic PL (PC, PS and PEA), the tendency was opposite: the SFA level increased while that of PUFA decreased, leading to a fall in the LUI and promoting a higher packing order of PL within the synaptic membrane. In the FA repertoire of the plasmalogen form of PEA (p-PEA), enforced hypothermia led to elevated levels both of SFA and PUFA as well as to a particularly high LUI, typical for this PL. These changes are supposed to be aimed at maintaining optimal membrane fluidity. We consider all the observed changes in lipid characteristics as adaptive, allowing the synaptic function in homeotherms to be supported as body temperature falls.



Physiological Functions and Metabolism of Endogenous Ethanol and Acetaldehyde in the Reindeer
Abstract
This study addresses for the first time the seasonal (winter–summer) dynamics of endogenous ethanol (EE) and acetaldehyde (EA) blood levels as well as of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities and catalytic properties in the liver of the reindeer. EE blood level was 1.89 ± 0.11 mM in summer and 1.41 ± 0.10 mM (i.e. 1.34 times lower) in winter (p< 0.05). Seasonal dynamics of EA blood levels was opposite: 3.06 ± 0.28 μM in summer and 12.62 ± 0.76 μM (i.e. 4.12 times higher) in winter (p< 0.05). In winter, there was a decrease in activities of ADHII in the acetaldehyde reduction reaction (4.0 times) and ALDH (3.3 times) in the liver (p< 0.05). This led to an increased winter blood level of EA in cold-adapted animals. Our results suggest that EE and EA, as interrelated metabolites, make up one of the systems that regulate the metabolic rate and eventually reduce the intensity of energy metabolism in the reindeer. This consi derably extends the possibilities for northern species to exist under extreme environmental conditions of cold regions. Apparently, a major ph ysiological function of the system that includes EE, EA and relevant enzymes is to increase cold tolerance of an organism due to the inhibitory effect of EA on mitochondrial terminal oxidation which reduces the intensity of aerobic processes.



Phospholipid and Fatty Acid Composition of Phosphatidylcholine and Phosphatidylethanolamine in the Black Plaice Pleuronectes obscura during Thermoadaptation
Abstract
The phospholipid (PL) and fatty acid (FA) composition of major membrane lipid constituents, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), as well as the cholesterol/phospholipid (CL/PL) ratio were assayed in the muscles, gills and liver of the black plaice Pleuronectes (Liopsetta) obscura at different ambient temperatures (18, 9 and 0°C). PL and CL were shown to be actively involved in adaptation of the fish to changes in the seawater temperature. As temperature declines, the monounsaturated FA (MUFA) level increases while the polyunsaturated FA (PUFA) fraction in gills and liver PC and PE, on the contrary, decreases, resulting in diminished functional activity of the fish. However, in muscles this correlation is lacking. The PC and PE composition was shown to be organ- and ambient temperature-dependent. Major PC forms are saturated FA (SFA)/PUFA and MUFA/PUFA composed of a relatively small number of major molecular species. A temperature drop results in an increased SFA/PUFA level and decreased MUFA/PUFA and PUFA/PUFA levels in muscles and gills, and this may promote a drop in the viscosity of the outer lipid monolayer of membranes and in their functional activity. In contrast to PC, the PE composition in all organs tested is characterized by a decrease in the SFA/ PUFA level and an increase in MUFA/PUFA and PUFA/PUFA levels. Such changes promote the retention of functional activity of the inner lipid monolayer of membranes and are not synchronized with rearrangements in their outer monolayer. Due to intermolecular transfer of acyl radicals at a constancy of their composition, functional rearrangement of the lipid matrix appears to be achieved through changes in the membrane viscosity. Our data support the idea that different adaptation strategies in fish are driven by certain sets of PL molecular species.



Alpha-Fetoprotein in Retina and Lens of the Human Eye at Early Stages of Prenatal Development
Abstract
The presence of alpha-fetoprotein (AFP) was shown in the retina and lens of the human fetal eye at different stages of prenatal development. PCR analysis revealed AFP mRNA neither in the retina nor in the lens, whereas in the fetal liver (control) AFP mRNA was found to be expressed. The data obtained indicate that AFP is not synthesized in retinal and lens cells of the human fetal eye but is imported from elsewhere to be taken up by these cells. The presence of AFP in the retina and lens implies its involvement in early morphogenesis and differentiation of these ocular tissues during prenatal human development.



Comparative and Ontogenic Physiology
Gender-Specific Features of Behavior and Lipid Spectrum in Rats at a Remote Period after Exposure to Vibrational Noise
Abstract
Changes in rat behavior and blood lipid spectrum were detected 3 weeks after exposure of animals to vibrational (construction) noise. Males demonstrated anxious, simplified or agitated behaviors, while females–anxious or depression-like behaviors. Most evident changes in the lipid spectrum were observed in males with simplified and females with depression-like behaviors. In anxious behavior, the high-density lipoprotein level was elevated in males and reduced in females versus control.



Antioxidant Status in Adolescents of Small Siberian Ethnoses
Abstract
The components of the antioxidant defense (AOD) system were analyzed in 74 male and female adolescents representing small ethnic groups that inhabit the territory of Eastern Siberia. Our findings indicate a dependence of the antioxidant status indicators on gender and ethnic identity of test subjects. More adaptive variants of the AOD system’s functioning were found in Tofalar boys (elevated levels of fat-soluble vitamins, increased glutathione system activity), whereas Evenk boys were characterized by a decreased activity of antioxidant factors (low α-tocopherol and retinol supply, glutathione system imbalance), as compared both to girls and Tofalar boys. The changes revealed in this group were also supported by increased values of the oxidative stress index.



Involvement of Mechanosensory Complex Structures of the Cricket Gryllus bimaculatus Larvae (Orthoptera, Gryllidae) in Triggering of Motor Responses to Sound
Abstract
Using an ethological approach, we studied the possibility of sound perception as well as probable contribution of diverse mechanosensory systems composing the mechanosensory complex to triggering of motor responses to sound stimulation in the cricket Gryllus bimaculatus larvae. It was shown that larvae can perceive sounds and respond to them by a locomotor reaction in a relatively broad frequency range, which becomes narrower as sound intensity decreases [0.1–6.6 kHz (111 ± 3 dB SPL), 0.1–1.4 kHz (101 ± 3 dB SPL), 0.1–0.8 kHz (91 ± 3 dB SPL]. Sound perception and triggering of motor responses appear to involve the cercal organs (CO), subgenual organs (SO) and, probably, other distant mechanosensory organs (DMO). Normal functioning of CO is essential for triggering locomotor responses to sound within the ranges of 1–1.4 kHz (101 ± 3 dB SPL) and 0.1–0.8 kHz (91 ± 3 dB SPL). CO are not necessary for triggering of motor responses to cues with an intensity of 111 ± 3 dB. SO and, probably, other DMO provide locomotor responses to sound within the ranges of 0.1–6.6 kHz (111 ± 3 dB SPL), 0.1–0.9 kHz (101 ± 3 dB SPL), and 0.1–0.3 kHz (91 ± 3 dB SPL). Thus, last instar larvae of G. bimaculatus lacking the tympanal organs can perceive sounds using CO, SO and, probably, other DMO, which (as in cricket imagoes) are likely to compose an integrated mechanosensory complex providing adequate acoustic behavior of this cricket species. Performance efficiency and sensitivity of the mechanosensory complex (specifically, CO) rely on the thoroughness of grooming. After self-cleaning of CO, the level of larval motor activity in response to cue presentation returned to the baseline and sometimes even increased. We assume that under normal conditions the mechanosensory complex, which triggers motor responses to a sound, is involved in the defensive escape response aimed at rescuing from predators.



Short Communications
Probability of Underwater Target Detection in the Bottlenose Dolphin Tursiops truncatus Depending on Target Spatial Coordinates



Effect of Electrical Stimulation of the Optic Nerve on Electroretinogram in the Pond Snail Lymnaea stagnalis


