Identification of Aerobic Methane-Oxidizing Bacteria in Coastal Sediments of the Crimean Peninsula

Microbiology - Methane oxidation rates and diversity of methane-oxidizing microorganisms in the upper sediment layers of the Crimean Peninsula coastal regions (Black Sea) were investigated....     

Metabolomic Analysis of Cerebrospinal Fluid Indicates Iron Deficiency Compromises Cerebral Energy Metabolism in the Infant Monkey

Iron deficiency anemia affects many pregnant women and young infants worldwide. The health impact is significant, given iron’s known role in many body functions, including oxidative and lipid metabolism, protein synthesis and brain neurochemistry. The following research determined if ¹H NMR spectroscopy-based metabolomic analysis of cerebrospinal fluid (CSF) could detect the adverse influence of early life iron deficiency on the central nervous system. Using a controlled dietary model in 43 infant primates, distinct differences were found in spectra acquired at 600 MHz from the CSF of anemic monkeys. Three metabolite ratios, citrate/pyruvate, citrate/lactate and pyruvate/glutamine ratios, differed significantly in the iron deficient infant and then normalized following the consumption of dietary iron and improvement of clinical indices of anemia in the heme compartment. This distinctive metabolomic profile associated with anemia in the young infant indicates that CSF can be employed to track the neurological effects of iron deficiency and benefits of iron supplementation.     

Structural studies of S-7, another exocellular polysaccharide containing 2-deoxy-arabino-hexuronic acid

The exocellular polysaccharide S-7, a heteropolysaccharide from Azotobacter indicus var. myxogenes has been studied using methylation analysis, Smith degradation, partial acid hydrolysis, NMR spectroscopy and mass spectrometry as the principal methods. It is concluded that the repeating unit has the following structure: [structure: see text] The absolute configuration of the deoxyhexuronic acid was deduced from 1H NMR chemical shifts and is most likely D. Approximately two O-acetyl groups per repeating unit are present, one of which is presumably on the Rha residue. The structure bears great resemblance to another polysaccharide, recently studied, produced by Sphingomonas paucimobilis I-886.     

Geochemical Peculiarities of the Carbonate Constructions Formed during Microbial Oxidation of Methane under Anaerobic Conditions

The aragonite constructions of the Black Sea are formed in a stable anaerobic zone and are a perfect object to study the natural mechanism of anaerobic methane oxidation. The most probable pathway of methane oxidation is its methanogen-mediated reaction with bicarbonates, dissolved in seawater, with the formation of water and acetate, which is then consumed by other components of the anaerobic community. Comparison of the ¹³C values of carbonate minerals and organic matter once more demonstrated that the formation of the organic matter of biomass is accompanied by intense fractionation of carbon isotopes, as a result of which the total organic matter of biomass acquires an extremely light isotopic composition, characterized by ¹³C values as low as –83.8.     

Solution structure and backbone dynamics of the KH-QUA2 region of the Xenopus STAR/GSG quaking protein

The Quaking protein belongs to the family of STAR/GSG domain RNA-binding proteins and is involved in multiple cell signalling and developmental processes in vertebrates, including the formation of myelin. Heteronuclear NMR methods were used to determine the solution structure of a 134 residue fragment spanning the KH and QUA2 homology regions of the Quaking protein from Xenopus laevis (pXqua) in the absence of RNA. The protein is shown to adopt an extended type I KH domain fold that is connected to a structured alpha-helix in the C-terminal QUA2 region by means of a highly flexible linker. A comparison with the solution structure of the related protein splicing factor 1 (SF1) indicates that most aspects of the RNA-binding interface are conserved in pXqua, although the "variable loop" region that follows the second beta-strand possesses two additional alpha-helices. The structure of pXqua provides an appropriate template for building models of important homologues, such as GLD-1 and Sam68. Measurements of the (15)N relaxation parameters of pXqua confirm that the polypeptide backbone of the QUA2 region is more dynamic than that of the KH portion, and that the C-terminal helix is partially structured in the absence of RNA. By comparison with a random coil reference state, the nascent structure in the QUA2 region is estimated to contribute 15.5kJmol(-1) to the change in conformational free energy that occurs on forming a complex with RNA. Since STAR/GSG proteins may regulate alternative splicing by competing with SF1 in the nucleus for specific branch-point sequences that signal intronic RNA, the formation of secondary structure in the QUA2 region in the unbound state of pXqua has important functional consequences.     

ATP-Mediated Compositional Change in Peripheral Myelin Membranes: A Comparative Raman Spectroscopy and Time-Of-Flight Secondary Ion Mass Spectrometry Study

In the present paper we addressed a mechanism of the myelin reorganization initiated by extracellular ATP and adenosine in sciatic nerves of the frog Rana temporaria. In combination with Raman microspectroscopy, allowing noninvasive live-cell measurements, we employed time-of-flight secondary ion mass spectrometry (TOF-SIMS) to follow the underlying changes in chemical composition of myelin membranes triggered by the purinergic agents. The simultaneous increase in lipid ordering degree, decrease in membrane fluidity and the degree of fatty acid unsaturation were induced by both ATP and adenosine. Mass spectrometry measurements revealed that ATP administration also led to the marked elevation of membrane cholesterol and decrease of phosphotidylcholine amounts. Vesicular lipid transport pathways are considered as possible mechanisms of compositional and structural changes of myelin.     

Inhibitory effect of angiostatins on activity of the plasminogen/plasminogen activator system

Angiostatins, kringle-containing fragments of plasminogen, are potent inhibitors of angiogenesis. Effects of three angiostatin forms, K1–3, K1–4, and K1-4.5 (0–2 μM), on the rate of native Glu-plasminogen activation by its physiological activators in the absence or presence of soluble fibrin were investigated in vitro. Angiostatins did not affect the intrinsic amidolytic activities of plasmin and plasminogen activators of tissue type (tPA) and urokinase type (single-chain scuPA and two-chain tcuPA), but inhibited conversion of plasminogen to plasmin in a dose-dependent manner. All three angiostatins suppressed Glu-plasminogen activation by tcuPA independently of the presence of fibrin, and the inhibitory effect increased in the order: K1-3 < K1-4 < K1-4.5. The inhibitory effects of angiostatins on the scuPA activator activity were lower and further decreased in the presence of fibrin. Angiostatin K1-3 (up to 2 μM) had no effect, while 2 μM angiostatins K1-4 and K1-4.5 inhibited the fibrin-stimulated Glu-plasminogen activation by tPA by 50 and 100%, respectively. The difference in effects of the three angiostatins on the Glu-plasminogen activation by scuPA, tcuPA, and tPA in the absence or presence of fibrin is due to the differences in angiostatin structures, mechanisms of action, and fibrin-specificity of plasminogen activators, as well as due to the influence of fibrin on the Glu-plasminogen conformation. Angiostatins in vivo, which mimic plasminogen-binding activity, can inhibit plasminogen activation stimulated by various proteins (including fibrin) of extracellular matrix, thereby blocking cell migration and angiogenesis. The data of this work indicate that the inhibition of Glu-plasminogen activation under the action of physiological plasminogen activators by angiostatins can be implicated in the complex mechanism of their antiangiogenic and antitumor action.     

The adaptations in muscle architecture following whole body vibration training

Objective:This study aims to investigate the effect of 8-week whole-body vibration (WBV) added to conventional training on muscular architecture, dynamic muscle strength and physical performance compared to controls in young basketball players.Methods:Sixteen young basketball players between the ages of 14-16 years were randomly assigned to whole body vibration group (VG) or control group (CG). Both groups were trained with a conventional program. Pennation angle (PeA), fascicle length and muscle thickness of Rectus Femoris (RF) and Vastus lateralis were measured by ultrasonography. Isokinetic dynamic muscle testing at 180 °/s and 60°/s, squat jump (SJ) and flexibility were evaluated before and after 8 weeks of training programs. Primary outcome measure was the fascicle length.Results:Fascicle length of RF, SJ height and flexibility increased significantly within VG compared to pretraining (p<0.05). SJ height increased in VG compared to CG significantly following training (p<0.05). PeA, fascicle length, muscle thicknesses, strength and flexibility did not differ between groups.Conclusion:Eight weeks of WBV training improved fascicle length of RF, SJ height, and flexibility compared to pre-training. Addition of WBV to conventional training did not cause improvement in muscle architecture, strength and flexibility compared to conventional training alone.     

Streptokinase-polyethylene glycol conjugates with increased stability and reduced side effects

Covalent SK-PEG2 and SK-PEG5 conjugates with various degrees of modification of the protein amino groups were obtained by variation of the duration of streptokinase (SK) incubation with activated polyethylene glycol (M 2 and 5 kDa, PEG2 and PEG5); their properties were studied in comparison with the properties of unmodified SK in vitro. SK-PEG2 and SK-PEG5 conjugates with the highest stability in plasma retaining 80% of initial fibrinolytic activity were formed at modification degrees of 54 and 52%, respectively. Interaction of the conjugates with equimolar plasminogen resulted in the formation of plasmin (Pm) activator complexes Pm·SK-PEG2 and Pm·SK-PEG5 with the maximum amidase activity being the same as that of Pm complex with native SK. Catalytic efficiency of plasminogen activation (k _Pg/K _Pg) was found to be slightly higher (2.84 min^?1 μM^?1) in case of Pm·SK-PEG2 complex and slightly lower, in case of the Pm·SK-PEG5 complex (1.17 min^?1 μM^?1), if compared to that of the unmodified complex Pm·SK (2.1 min^?1 μM^?1). Investigation of lysis kinetics of human plasma clot and depletion of plasminogen and fibrinogen plasma levels under the effect of equal doses of SK in free and conjugated forms demonstrated that SK-PEG2 and SK-PEG5 conjugates possess high thrombolytic activity (89 and 72% to the activity of free SK, respectively) and cause 3.5–4-fold lower side effects than free SK. The SK-PEG2 and SK-PEG5 conjugates with increased stability in plasma and reduced side effects may be used in therapy of thrombotic disorders.     

Carbonic Anhydrase and Urease Inhibitory Potential of Various Plant Phenolics Using in vitro and in silico Methods

Plant phenolics are known to display many pharmacological activities. In the current study, eight phenolic compounds, e.g., luteolin 5‐O‐β‐glucoside ( 1 ), methyl rosmarinate ( 2 ), apigenin ( 3 ), vicenin 2 ( 4 ), lithospermic acid ( 5 ), soyasaponin II ( 6 ), rubiadin 3‐O‐β‐primeveroside ( 7 ), and 4‐(β‐d ‐glucopyranosyloxy)benzyl 3,4‐dihydroxybenzoate ( 8 ), isolated from various plant species were tested at 0.2 mm against carbonic anhydrase‐II (CA‐II) and urease using microtiter assays. Urease inhibition rate for compounds 1  –  8 ranged between 5.0 – 41.7%, while only compounds 1 , 2 , and 4 showed a considerable inhibition over 50% against CA‐II with the IC₅₀ values of 73.5 ± 1.05, 39.5 ± 1.14, and 104.5 ± 2.50 μm , respectively, where IC₅₀ of the reference (acetazolamide) was 21.0 ± 0.12 μm . In silico experiments were also performed through two docking softwares (Autodock Vina and i‐GEMDOCK) in order to find out interactions between the compounds and CA‐II. Actually, compounds 6 (30.0%) and 7 (42.0%) possessed a better binding capability toward the active site of CA‐II. According to our results obtained in this study, among the phenolic compounds screened, particularly 1 , 2 , and 4 appear to be the promising inhibitors of CA‐II and may be further investigated as possible leads for diuretic, anti‐glaucoma, and antiepileptic agents.