European checkerspots (Melitaeini: Lepidoptera,Nymphalidae) are not aposematic – the point of view of great tits (Parus major)

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Transition metal complexes bearing atropisomeric saturated NHC ligands

From achiral imidazolinium salts, chiral transition metal complexes containing an N-heterocyclic carbene (NHC) ligand were prepared (metal = palladium, copper, silver, gold, rhodium). Axial chirality in these complexes results from the formation of the metal-carbene bond leading to the restriction of rotation of dissymmetric N-aryl substituents about the C–N bond. When these complexes exhibited a sufficient configurational stability, a resolution by chiral high-performance liquid chromatography (HPLC) on preparative scale enabled isolation of enantiomers with excellent enantiopurities (>99% ee) and good yields. A study of the enantiomerization barriers revealed the effect of the backbone nature as well as the type of transition metal on its values. Nevertheless, the evaluation of palladium-based complexes in asymmetric intramolecular α-arylation of amides demonstrated that the ability to induce an enantioselectivity cannot be correlated to the configurational stability of the precatalysts.     

Plasminogen activator from Agkistrodon halys halys venom

Plasminogen activator "Ahh-32" from Agkistrodon halys halys venom has been isolated and purified using affinity and ion-exchange chromatography. The purified enzyme consists of the single peptide-chain with molecular weigth of 32 kDa. It can convert free plasminogen into active form--plasmin. "Ahh-32" was inhibited by DFP and benzamidine. Besides, the enzyme influences significantly the activation of plasminogen by streptokinase without having effect on analogical process in case of usage of tissue tipe plasminogen activator. The obtained protein can be used as an instrument under investigation of protein-protein interactions in haemostasis system.     

ONTOGENETIC NICHE SHIFT IN THE BRACHIOPOD TEREBRATALIA TRANSVERSA: RELATIONSHIP BETWEEN THE LOSS OF ROTATION ABILITY AND ALLOMETRIC GROWTH

Abstract: Many articulated brachiopods experience marked life habit variations during ontogeny because they experience their fluid environment at successively higher Reynolds numbers, and they can change the configuration of their inhalant and exhalant flows as body size increases. We show that the extant brachiopod Terebratalia transversa undergoes a substantial ontogenetic change in reorientation governed by rotation around the pedicle. T. transversa′s reorientation angle (maximum ability to rotate on the pedicle) decreases during ontogeny, from 180 degrees in juveniles to 10–20 degrees in individuals exceeding 5 mm, to complete cessation of rotation in individuals larger than 10 mm. Rotation ability is substantially reduced after T. transversa achieves the adult lophophore configuration and preferred orientation with respect to ambient water currents at a length of 2.5–5 mm. We hypothesize that the rotation angle of T. transversa is determined mainly by the position of ventral and dorsal points of attachment of dorsal pedicle muscles relative to the pedicle. T. transversa shows a close correlation between the ontogenetic change in reorientation angle and ontogeny of morphological traits that are related to points of attachment of dorsal pedicle muscles, although other morphological features can also limit rotation in the adult stage. The major morphological change in cardinalia shape and the observed reduction of rotation affect individuals 2.5–10 mm in length. The position of ventral insertions of dorsal pedicle muscles remains constant, but contraction of dorsal pedicle muscles is functionally handicapped because dorsal insertions shift away from the valve midline, rise above the dorsal valve floor, and become limited by a wide cardinal process early in ontogeny (<5 mm). The rate of increase of cardinal process width and of distance between dorsal pedicle muscle scars substantially decreases in the subadult stage (5–10 mm), and most of the cardinalia shell traits grow nearly isometrically in the adult stage (>10 mm). T. transversa attains smaller shell length in crevices than on exposed substrates. The proportion of small‐sized individuals and population density is lower on exposed substrates than in crevices, indicating higher juvenile mortality on substrates prone to grazing and physical disturbance. The loss of reorientation ability can be a consequence of morphological changes that strengthen substrate attachment and maximize protection against biotic or physical disturbance (1) by minimizing torques around the pedicle axis and/or (2) by shifting energy investments into attachment strength at the expense of the cost involved in reorientation.     

Response of eutrophication in the eastern Gulf of Finland to nutrient load reduction scenarios

The trophic status of the eastern Gulf of Finland, where the largest Baltic metropolis St. Petersburg sits at the mouth of the largest Baltic river Neva, is elevated but existing recommendations on water protection measures are controversial. In this study, the effects of nutrient load reductions on this ecosystem were estimated with the aid of a three-dimensional coupled hydrodynamic-biogeochemical model. As a reference, the contemporary seasonal dynamics were simulated with nutrient inputs corresponding to the recent estimates of point and riverine sources. In order to eliminate the effects of natural inter-annual variations, the computations were run under recurrent annual forcing for 3 years, until quasi steady-state seasonal dynamics were reached. Reasonable comparability of simulated concentrations and biogeochemical fluxes to available field estimates provides credibility to scenario simulations. These simulations show that substantial reductions of nutrient point sources in St. Petersburg would affect only the Neva Bay as the immediate receptor of treated sewage waters, where primary production could decrease by up to 20%. Eutrophication in the other parts of the Neva Estuary and in the entire eastern Gulf of Finland would change insignificantly owing to increased nutrient import from the offshore waters. Therefore, more significant changes can occur only via a reduction in nutrient pools in the open Gulf of Finland and the Baltic Proper, which would require a longer time. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark     

Method for endogenous formaldehyde evaluation in animal organism

A method for endogenous formaldehyde (FA) level evaluation has been worked out. The method involves the administration of dimedone, which forms the stable complex with FA, and the determination of formaldimedone concentration in biological samples by the fluorescence approach. The method was tested on rat's models of FA metabolism modulation. Animals received FA (10 mg/kg); or methylamine - substrate of FA-generating enzyme SSAO, (250 mg/kg); or semicarbazide - SSAO inhibitor, (200 mg/kg). Concentration of FA bound with dimedone in the liver tissue were, correspondingly: 7.5 +/- 1.5 mkg/kg; 5.4 +/- 0.9 mkg/kg; 2.4 +/- 0.7 mkg/kg; control - 4.2 +/- 1.4 mkg/kg. Obtained data indicate, that the elaborated method gives reliable information about FA level.     

Characterization of platelets aggregation inhibitor from Agkistrodon blomhoffii ussuriensis snake venom

Platelet aggregation inhibitor--"Blomus-B" from Agkistrodon blomhoffii ussuriensis venom has been isolated by affinity and ion-exchange chromatography. The purified inhibitor is a novel non-enzymatic single-chain protein with molecular weigth of 13 kDa. "Blomus-B" causes a change of platelets shape and takes effect on ADP- and adrenalin-induced platelet aggregation.     

Process of complexation of prothrombine and fibrin E-fragment

The study is devoted to research of the blood coagulation key proenzyme complexation process. It is prothrombin, and the E-fragment of fibrin can be a component in blood circulation. It is shown, that non-enzyme activation of prothrombin by the E-fragment proceeds as a result of formation of stable non-covalent prothrombin-E fragment complex. The cringle structures of prothrombin and the N-terminal site of beta-chain of E-fragment of fibrin are important for formation of the given complex. It has been defined, that other fragments of fibrin (D and DD) are not capable to induce amydolytic activity of prothrombin.     

The comparison of levels of anxiety and stress response in mice selected for low and high brain weight

Emotionality, anxiety and stress reactivity were studied in mice selected for large (LW) and small (SW) brain weight. The open-field test, startle reaction, cross-maze, tail suspension and slippery funnel tests were used. It was shown that the SW mice are more active in the open field, more anxious and predisposed to the stereotyped behavior and passive reactions in stress situations. The relationship between the studied traits and brain weight and their influence on cognitive behavior are discussed.