The immunomorphologic analysis of innervation of chromaffin paraganglian cells of the mammalian arteries and heart

Innervation of chromaffin cells of paraganglia of the wall of mammalian large arterial vessels and heart (in rat, cat, and human) was studied by neuromorphological and immunohistochemical methods. There is established similarity in structure of specialized, "basket"-type nerve endings of the chromaffin cells (ChC) with pericellular nerve apparatuses of sympathetic and parasympathetic autonomic neurons. It is proposed to use immunohistochemical reaction for synaptophysin as method of selective detection of ChC of paraganglia and adrenal medulla. The conclusion is made that synaptophysin-positive terminals (SPPT) found on bodies of ChC and postganglionic neurons represent efferent, rather than afferent, synapses formed by myelinated axons of preganglionic fibers. It is suggested that ChC of paraganglia alongside with their characteristic endocrine function participate in complex mechanisms of chemoreceptor regulation of tissue homeostasis of mammalian blood vessels and heart.     

Cortical slow negative potentials during eye fixation and preparing of visually triggered saccades in a man

In 10 right-handed healthy subjects EEGs preceding saccades with mean latent periods were selectively averaged. Two standard schemes of visual stimulation were used: with immediate presentation of a peripheral target stimuli after the central fixation stimulus (a single step paradigm) and with the interval between the stimuli in 200 ms (GAP paradigm). Two waves of slow premotor negativity (early PMN1 and late PMN2) that appeared 930 +/- 79 and 609 +/- 82 ms, respectively, prior to a saccade onset were observed. The PMN2 was followed by the negative potentials N-3, N-2, and N-1 (saccadic initiation potential). It was found that in GAP stimulation condition the PMN1 was less pronounces and N-1 was increased as compared to the single step. These findings suggest that disengage of attention from the central point during the GAP period clears the saccadic system for decision making and initiation of a saccade. Under such conditions, the expectation of a visual target does not require a high level of nonspecific activation and motor attention.     

Abnormal condensation of meiotic chromosomes caused by the mei8 mutation in rye Secale cereale L

Inheritance of two spontaneous meiosis-specific mutations with similar cytologic phenotype was studied. Both mutations were independently obtained from two rye populations (Vyatka variety and weedy rye). Both mutations are recessive, allelic, and monogenically inherited; the corresponding gene is designated mei8. The mutant alleles of the gene cause abnormal meiotic chromosome structure expressed as irregular compaction along the chromosome length, chromatin stickiness at all stages of meiosis, and chromosome fragmentation in anaphase I.     

The hybridization of tetraploid wheat with the octoploid wheat-wild rye amphiploid Elytricum fertile and the chromosome behavior in meiotic MI

The hybridization and chromosome behaviour regularities at meiotic MI of reciprocal F1 hybrids of tetraploid wheats T. durum and T. turgidum with 56-chromosome incomplete wheat-Elymus amphiploid (IWEA) Elytricum fertile, were investigated. Variation of main indices of the hybridization has been revealed to be determined by variance of such factors as cross direction, genotype peculiarities of wheat strains and their interaction. Elymus sibiricus genome, contained in IWEA karyotype, carries several genes, that can suppress wheat diploidization system. Reduction of homologous chromosome synapsis is not determined by these genes, but is connected with influence of other Elymus sibiricus chromosome factors.     

Paradoxical vagal effects on the cardiac rhythm in cats

In anaesthetised cats, an increase in the vagal burst rate resulted in a paradoxical decrease of vagal bradycardia. This seems to be due to a shift of the vagal stimulus position towards early phase of cardiac cycle. The mechanism of this paradoxical effect depends on the magnitude of vagal chronotropic effect upon the time of vagal stimulus delivery within cardiac cycle.     

Detection of carotenoids in the vitreous body of the human eye during prenatal development

Carotenoids were found for the first time in the vitreous body of human eye during the fetal period from week 15 until week 28. Their maximum content was timed to week 16-22. No carotenoids were found the vitreous body of 31-week fetuses, as well as adult humans, which corresponds to the published data. It was shown using HPLC that chromatographic characteristics of these carotenoids correspond to those of lutein and zeaxanthin, characteristic pigments of the retinal yellow macula.     

The synthesis and antiviral activity of glycyrrhizic acid conjugates with alpha-D-glucosamine and some glycosylamines

Glycyrrhizic acid and its 30-methyl ester were conjugated with 2-amino-1,3,4,6-tetra-O-acetyl-2-deoxy-alpha-D-glucopyranose, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl amine, 2,3,4-tri-O-acetyl-apha-L-arabinopyranosyl amine, 2-acetamido-2-deoxy-beta-D-glucopyranosyl amine, and beta-D-galactopyranosyl amine using N,N'-dicyclohexylcarbodiimide and its mixtures with N-hydroxybenzotriazole. Structures of the conjugates were confirmed by IR, UV, 1H, and 13C NMR spectroscopy. The glycoconjugate with the residues of 2-acetamido-2-deoxy-beta-D-glucopyranosyl amine in the carbohydrate part of its molecule exhibited antiviral activity (ID50 4 microg/ml) toward the herpes simplex type 1 virus (HSV-1) in the VERO cell culture. Two compounds demonstrated anti-HIV-1 activity (50-70% inhibition of p24) in a culture of MT-4 cells at concentrations of 0.5-20 microg/ml. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.     

Local disinhibition with bicuculline does not break the trained relationship between afferent input and efferent output in cat motor cortex

Neurons of the cat motor cortex related to the lifting-withdrawal phase of forepaw placing reaction are preferentially activated by tactile stimulation of the dorsal surface of the forepaw. The placing reaction was altered in such a way that the innate "dorsal placing" was subjected to extinction and was substituted for the newly acquired conditioned reaction in response to the ventral side stimulation. This alteration of placing reaction led to the inversion of the innate input-output relationship in the motor cortex. The neurons related to forepaw lifting-withdrawal began to be activated by tactile stimulation of the ventral rather than dorsal forepaw surface. Local cortical disinhibition by bicuculline application at the recording site qualitatively changed neither normal input-output relationships nor inverse relationships after placing reaction alteration. This suggests that alteration of the sensorimotor coordination in cat motor cortex is underlain by changes in excitatory rather than inhibitory connections.     

Aerobic methanotrophic communities in the bottom sediments of Lake Baikal

The results of the first methodical investigation into the aerobic methanotrophic communities inhabiting the bottom sediments of Lake Baikal are reported. Use of the radioisotopic method revealed methane consumption in 12 10- to 50-cm-long sediment cores. The maximum methane consumption rates (495-737 microl/(dm3 day) were recorded in sediments in the regions of hydrothermal vents and oil and gas occurrence. Methane consumption was most active in the surface layers of the sediments (0-4 cm); it decreased with the sediment depth and became negligible or absent at depths below 20 cm. The number of methanotrophic bacteria usually ranged from 100 to 1000 cells/cm3 of sediment and reached 1 million cells/cm3 in the regions of oil and gas occurrence. The 17 enrichment cultures obtained were represented mainly by morphotype II methanotrophs. Phylogenetic analysis of the enrichment cultures in terms of the amino acid sequence of the alpha subunit of the membrane-bound methane monooxygenase revealed the predominance of methanotrophs of the genus Methylocystis. The results obtained suggest the presence of an active aerobic methanotrophic community in Lake Baikal.