Up-regulation of GABAB Receptor Signaling by Constitutive Assembly with the K+ Channel Tetramerization Domain-containing Protein 12 (KCTD12)

GABA_B receptors are the G-protein coupled receptors (GPCRs) for GABA, the main inhibitory neurotransmitter in the central nervous system. Native GABA_B receptors comprise principle and auxiliary subunits that regulate receptor properties in distinct ways. The principle subunits GABA_B1a, GABA_B1b, and GABA_B2 form fully functional heteromeric GABA_B(1a,2) and GABA_B(1b,2) receptors. Principal subunits regulate forward trafficking of the receptors from the endoplasmic reticulum to the plasma membrane and control receptor distribution to axons and dendrites. The auxiliary subunits KCTD8, -12, -12b, and -16 are cytosolic proteins that influence agonist potency and G-protein signaling of GABA_B(1a,2) and GABA_B(1b,2) receptors. Here, we used transfected cells to study assembly, surface trafficking, and internalization of GABA_B receptors in the presence of the KCTD12 subunit. Using bimolecular fluorescence complementation and metabolic labeling, we show that GABA_B receptors associate with KCTD12 while they reside in the endoplasmic reticulum. Glycosylation experiments support that association with KCTD12 does not influence maturation of the receptor complex. Immunoprecipitation and bioluminescence resonance energy transfer experiments demonstrate that KCTD12 remains associated with the receptor during receptor activity and receptor internalization from the cell surface. We further show that KCTD12 reduces constitutive receptor internalization and thereby increases the magnitude of receptor signaling at the cell surface. Accordingly, knock-out or knockdown of KCTD12 in cultured hippocampal neurons reduces the magnitude of the GABA_B receptor-mediated K⁺ current response. In summary, our experiments support that the up-regulation of functional GABA_B receptors at the neuronal plasma membrane is an additional physiological role of the auxiliary subunit KCTD12.     

Blood lactate dehydrogenase activity in newborn children

Arterial and venous blood samples from babies' umbilical cord vessels before lung breath beginning were used to measure arterial-venous difference between lactate dehydrogenase activity, pH and oxygen blood saturation (sO2). Enzyme activity was 735.4 +/- 90.8 U/L in venous blood and 672.0 +/- 108.1 U/L in arterial one, pH 7.21 +/- 0.06 and 7.32 +/- 0.06, sO2 32.9 +/- 12.7 and 56.5 +/- 18.3%, respectively. Reverse correlation between enzyme activity, pH and sO2 was found.     

Effect of chemical defoaming agents on the mass exchange rate in the oxytetracycline biosynthesis process

The effect of chemical foam suppressors of various classes on the intensity of Streptomyces rimosus respiration, concentrations of dissolved oxygen and carbon dioxide and gas levels in the fermentation broth of oxytetracycline was studied. Its was shown that addition of the foam suppressors, as a rule, resulted in a decreased rate of the oxygen mass transfer due to the decreased surface of the phase contact gas-liquid. This decrease was not so significant as that in case of uninhibited intensity of the fermentation broth foaming. A different character of the effect of different foam suppressors on the biosynthetic process was noted. The effect of the foam suppressors was decreased by their regular addition in low amounts.     

Bioresorption of Porous 3D Matrices Based on Collagen in Liver and Muscular Tissue

Highly porous cylinder-shaped 3D matrices with diameters of 1.3 and 3 mm were obtained by lyophilization of collagen solution. A study in vivo of the mechanism and rate of resorption of the resulting material showed that complete resorption of the matrix occurred 6 weeks after their implantation into liver tissue and 3 weeks after implantation into muscle tissue of animals. Surrounding tissues were not altered or damaged. Histological analysis revealed that, simultaneously with the resorption of matrix collagen, connective tissue and blood vessels were formed. This allows us to recommend the developed porous material based on collagen for use as matrices for tissue engineering and cellular transplantation.     

Reversal of sides in the blackfin flounder Glyptocephalus stelleri and variability of body pigmentation and shape in pleuronectid flatfishes

A specimen of the blackfin flounder Glyptocephalus stelleri showing a reversal of the body sides was found for the first time. Records of flounders of the genus Pseudopleuronectes with abnormal body coloration are given. The occurrence of pigmentation on both sides of the body and the reversal of sides are indicative of the manifestation of atavism in flatfishes. The high variability of phenotypic characters, which is common to some species of flatfish with clinal variations, is illustrated using the example of the marbled flounder.     

Interpopulation morphological variability of the viviparous pipefish Syngnathus acusimilis Günther, 1873 (Teleostei: Syngnathidae)

In viviparous fish, as is illustrated by the example of the pipefish Syngnathus acusimilis (Syngnathidae), unlike fish that spawn their eggs into the environment, there are virtually no differences between populations in meristic characters, which are formed during the embryonic and larval development. The absence of these differences is due to the stability of conditions, specifically temperature, during the egg incubation in the parental organism. The insignificant differences in the external morphology of the pipefish can also be associated with the presence of the bony plates that completely cover the fish body. The peculiarities of the structure and reproductive biology are not conducive to the ecological and geographical intraspecific differentiation of this fish.     

Ecological subspecies and locally temporal populations of anadromous fish

Intraspecific organization and structure of anadromous fish populations (in terms of species of the Oncorhynchus, Salvelinus, and Tribolodon genuses) were investigated. It was shown that the ecological, genetic, and morpho-physiological differences in ecology-temporal (seasonal) races of these fish reached the rank of ecological subspecies. The expediency of more careful and detailed study of intraspecific organization, ecological and locally temporal differentiation of fish, and consideration of the results of these researches was shown in the development of a polymorphic species concept as well as optimization of fish industry—the sustainable organization of fishing, artificial fish breeding, and introduction of fish.