Determination of minimal concentrations of biocorrosion inhibitors by a bioluminescence method in relation to bacteria, participating in biocorrosion

By using a bioluminescence ATP assay, we have determined the minimal concentrations of some biocorrosion inhibitors (Katon, Khazar, VFIKS-82, Nitro-1, Kaspii-2, and Kaspii-4) suppressing most common microbial corrosion agents: Desulfovibrio desulfuricans, Desulfovibrio vulgaris, Pseudomonas putida, Pseudomonas fluorescens, and Acidithiobacillus ferrooxidans. The cell titers determined by the bioluminescence method, including not only dividing cells but also their dormant living counterparts, are two- to sixfold greater than the values determined microbiologically. It is shown that the bioluminescence method can be applied to determination of cell titers in samples of oil-field waters in the presence of iron ions (up to 260 mM) and iron sulfide (to 186 mg/l) and in the absence or presence of biocidal corrosion inhibitors.     

Receptor binding on whole cells can oscillate.

The study of the kinetics of binding of the opiate receptor agonist [3H]DADLE with NG108-15 cell suspensions has revealed a new periodic biological phenomenon, i.e., oscillations of the cellular receptor activity. The absence of oscillations for binding of the receptor antagonist shows that oscillations occur as a result of the transformation of the receptor signal only.     

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.     

Prostaglandin-like inhibitors of prostaglandin-H-synthase

The effect of none prostaglandin-like cyclopentanone derivatives on the prostaglandin H synthase activity was studied. Seven substances proved to be inhibitors of the enzyme, some of the being similar to the well-known nonsteroid antiinflammatory drugs with respect to their inhibitory activity.     

Mass-transfer and kinetics of microencapsulated alpha-chymotrypsin action]

A theoretical model for transient and steady-state kinetics of microencapsulated enzymes action has been developed. The model is meant to overcome the diffusional limitations, caused by a microcapsulated membrane. The effects of various parameters (enzymatic reaction rate constants, enzyme concentration in microcapsules, membrane permeability, substrate concentration, and bulk pH values) on the overall apparent reaction rate have been analyzed using esters hydrolysis catalyzed by alpha-chymotrypsin encapsulated into polycarbonate membranes as an example.     

Comparison of anti-aggregatory activities of 5-phenyl-3-(3-pyridyl)isoxazole and 5-phenyl-3-(3-pyridyl)-1,2,4-oxadiazole

Two bioisosteric analogs, 5-phenyl-3-(3-pyridyl)isoxazole and 5-phenyl-3-(3-pyridyl)-1,2,4-oxadiazole, were synthesized so as to compare their antiaggregatory activities, to determine a pharmacologically active fragment in molecules of this type, and to explore the mechanisms of action of potential antiag-gregatory compounds belonging to the class of 3,5-substituted isoxazoles. Antiaggregatory activities of these compounds were studied in vitro using three aggregation inducers, such as arachidonic acid, adenosine diphosphate, and adrenaline. It was shown that 5-phenyl-3-(3-pyridyl)-1,2,4-oxadiazole and 5-phenyl-3-(3-pyridyl)isoxazole completely suppressed platelet aggregation induced by arachidonic acid and the second wave of platelet aggregation induced by adrenaline or adenosine diphosphate. The antiaggregatory activity of substituted isoxasole was 1.1–1.5 times higher than that of substituted oxadiazole. In contrast to the isoxazole analog, 5-phenyl-3-(3-pyridyl)-1,2,4-oxadiazole in concentrations of 300–400 μM partially suppressed the first wave of aggregation induced by adenosine diphosphate. It was demonstrated that both compounds were not thrombin inhibitors in vitro at concentrations up to 250 μM. Thus, introduction of a nitrogen atom into the C4-position of the isoxazole ring changes the molecule properties. It suggests that the pharmacophoric fragment of the molecule should be the whole isoxazole or 1,2,4-oxadiazole ring but not a part of the ring as was supposed previously.     

Avian biodiversity in the coastal wetlands of the Okahukura Peninsula

The Tapora Landcare Group, operating on the Okahukura Peninsula, has the long-term goal of making this region predator fenced. The aim of this study was to obtain information on the current status of avian biodiversity and the bird community across the band of coastal wetlands on the Okahukura Peninsula. Bird counts were conducted and playback lures used to detect three cryptic wetland species: fernbirds (Bowdleria punctata); spotless crakes (Porzana tabuensis); and banded rails (Gallirallus philippensis). Fernbirds and banded rails were detected at seven of the eight wetland sites sampled whereas spotless crakes were detected at two sites. The native species with the highest relative abundance across the eight sites were silvereyes (Zosterops lateralis) and South Island pied oystercatchers (Haematopus finschi). Changes in avian biodiversity over time in the region can now be monitored, and comprehensive long-term data on the status of avian biodiversity over time obtained.     

OTUB1 modulates c‐IAP1 stability to regulate signalling pathways

The cellular inhibitor of apoptosis (c‐IAP) proteins are E3 ubiquitin ligases that are critical regulators of tumour necrosis factor (TNF) receptor (TNFR)‐mediated signalling. Through their E3 ligase activity c‐IAP proteins promote ubiquitination of receptor‐interaction protein 1 (RIP1), NF‐κB‐inducing kinase (NIK) and themselves, and regulate the assembly of TNFR signalling complexes. Consequently, in the absence of c‐IAP proteins, TNFR‐mediated activation of NF‐κB and MAPK pathways and the induction of gene expression are severely reduced. Here, we describe the identification of OTUB1 as a c‐IAP‐associated deubiquitinating enzyme that regulates c‐IAP1 stability. OTUB1 disassembles K48‐linked polyubiquitin chains from c‐IAP1 in vitro and in vivo within the TWEAK receptor‐signalling complex. Downregulation of OTUB1 promotes TWEAK‐ and IAP antagonist‐stimulated caspase activation and cell death, and enhances c‐IAP1 degradation. Furthermore, knockdown of OTUB1 reduces TWEAK‐induced activation of canonical NF‐κB and MAPK signalling pathways and modulates TWEAK‐induced gene expression. Finally, suppression of OTUB1 expression in zebrafish destabilizes c‐IAP (Birc2) protein levels and disrupts fish vasculature. These results suggest that OTUB1 regulates NF‐κB and MAPK signalling pathways and TNF‐dependent cell death by modulating c‐IAP1 stability.     

First Globus-M2 Results

Plasma Physics Reports - Globus-M2—a new 1-Tesla spherical tokamak—was recently launched. The main features and research directions of this machine in scope of fusion–fission...     

Metabolic dysfunction and relationship in human frontoparietal cortex in severe traumatic brain injury: Single-voxel <Superscript>1</Superscript>H magnetic resonance spectroscopy study

¹H-magnetic resonance spectroscopy revealed that apparently normal (from the data of magnetic resonance imaging) human brain frontoparietal cortex in the subacute stage of traumatic brain injury is characterized by decreased level of N-acetylaspartate (NAA) and increase in levels of myoinositol, choline-containing compounds (Cho), and creatine/phosphocreatine (Cr). Correlations between Cr, Cho, and NAA were established. We propose a scheme of neuronal metabolic processes that joins these substances.