Wip1 phosphatase positively modulates dendritic spine morphology and memory processes through the p38MAPK signaling pathway

Dendritic spine morphology is modulated by protein kinase p38, a mitogen-activated protein (MAPK), in the hippocampus. Protein p38MAPK is a substrate of wip1, a protein phosphatase. The role of wip1 in the central nervous system (CNS) has never been explored. Here, we report a novel function of wip1 in dendritic spine morphology and memory processes. Wip1 deficiency decreases dendritic spine size and density in pyramidal neurons of the hippocampal CA1 region. Simultaneously, impairments in object recognition tasks and contextual memory occur in wip1 deficient mice, but are reversed in wip1/p38 double mutant mice. Thus, our findings demonstrate that wip1 modulates dendritic morphology and memory processes through the p38MAPK signaling pathway. In addition to the well-characterized role of the wip1/p38MAPK in cell death and differentiation, we revealed the novel contribution of wip1 to cognition and dendritic spine morphology, which may suggest new approaches to treating neurodegenerative disorders.     

Two new species of Pseudohadena Alphéraky, 1889 from Kazakhstan (Lepidoptera, Noctuidae, Xyleninae)

Two new species of Pseudohadena, Pseudohadena anatinesp. n. and Pseudohadena gorbunovisp. n. (Lepidoptera, Noctuidae) are described from Ustyurt, Kazakhstan. Illustrations of adults and the genitalia of both sexes are provided. Microstructures of vesicae are described and illustrated. A diagnostic comparison is made with Pseudohadena evanida psammoxantha Ronkay, Varga & Fábián, 1995, Pseudohadena magnitudinis Hacker & Ebert, 2002 and Pseudohadena pseudamoena (Boursin, 1943).     

Heterooligomeric complexes of human small heat shock proteins

Oligomeric association of human small heat shock proteins HspB1, HspB5, HspB6 and HspB8 was analyzed by means of size-exclusion chromatography, analytical ultracentrifugation and chemical cross-linking. Wild-type HspB1 and Cys mutants of HspB5, HspB6 and HspB8 containing a single Cys residue in position homologous to that of Cys137 of human HspB1 were able to generate heterodimers cross-linked by disulfide bond. Cross-linked heterodimers between HspB1/HspB5, HspB1/HspB6 and HspB5/HspB6 were easily produced upon mixing, whereas formation of any heterodimers with participation of HspB8 was significantly less efficient. The size of heterooligomers formed by HspB1/HspB6 and HspB5/HspB6 was different from the size of the corresponding homooligomers. Disulfide cross-linked homodimers of small heat shock proteins were unable to participate in heterooligomer formation. Thus, monomers can be involved in subunit exchange leading to heterooligomer formation and restriction of flexibility induced by disulfide cross-linking prevents subunit exchange.     

Phosphorylation of troponin in the heart and skeletal muscle by Ca2+-phospholipid-dependent protein kinase

The phosphorylation of the whole troponin complex and of the cardiac and skeletal troponin components by Ca2+-phospholipid-dependent protein kinase was studied. The activity of enzyme isolated from rat brain by ion-exchange chromatography on DEAE-Sephadex and by affinity chromatography on phosphatidylserine immobilized on polyacrylamide gel was shown to be completely dependent on Ca2+ and phospholipids and was equal to 0.4-0.6 mumol of phosphate/min.mg protein with histone H1 as substrate. The resulting preparation of Ca2+-phospholipid-dependent protein kinase was able to phosphorylate the isolated troponin I; the amount of phosphate transferred per mol of cardiac and skeletal troponin I was equal to 1.1 and 0.4, respectively. The maximal degree of phosphorylation of isolated troponin T by Ca2+-phospholipid-dependent protein kinase was 0.6 mol of phosphate per mol of troponin T both for skeletal and cardiac proteins. The rate and degree of phosphorylation were independent of the initial level of troponin T phosphorylation. Ca2+-phospholipid-dependent protein kinase did not phosphorylate the first serine residue of troponin T, i.e., the site which was phosphorylated in the highest degree after isolation of troponin T from skeletal muscles. The data obtained and the fact that the rate and degree of phosphorylation of troponins I and T within the whole troponin complex are 10-20 times less than those for isolated components provide little evidence for the participation of protein kinase C in troponin phosphorylation in vivo.     

Identification of digitonin binding sites on the plasma membrane of the rabbit aorta endotheliocytes

Specific reagents comprising digitonin bound to latex spheres were used as visual markers for the detection of cholesterol sites on the endothelial cell surface by scanning electron microscopy. The distribution of latex markers in the plasmolemma of the endothelial cells was investigated. These markers have strong bonds with the ligands. This interaction guarantees high specificity of binding between labeled markers and cellular membrane cholesterol.     

On the definition of active transport

A reappraisal of recently proposed definitions and criteria of active transport in terms of experimentally accessible parameters leads to the conclusion that it is in principle impossible to give a rigorous quantitative defintion of the active component of the flux of a specific molecular species across a membrane without prior knowledge of the mechanism. The attempted distinctions between various types of “non-passive” transport (coupled, forced, facilitated, etc.) are thus of necessity operationally ambiguous. The essential equivalence of formulations based on classical thermodynamics and on thermodynamics of irreversible processes is pointed out, and the significance of Curie’s theorem to any theoretical formulation is discussed.     

A model for optimal processing of multisensory information in the system for maintaining body orientation in the human

Considered is the optimal processing of multisensory information to maintain body orientation in the human. It is supposed that the orientation is performed by a system of angular stabilization with only small deviations from the equilibrium believed to be coincided with the local vertical. The linear transformation is determined which minimizes the square loss function for the stabilization error. This transformation comprises two successive steps. One of them is the averaging procedure on the the sensory inputs and the other is the optimal Kalman filtering in time domain. It is shown that the presence of two interacting channels for angular position and angular velocity in the structure of the optimal filter ensures sufficient accuracy of stabilization in both channels for the stabilization system as a whole in spite of the substantial unreliability in transmission in the channel of the angular position.     

The first results of meiobenthos study in the Cái River (Central Vietnam)

The first data on the composition and quantitative development of meiobenthos in the small tropical Cái River (Central Vietnam) at the end of the “small rainy season” (early June) have been obtained. In the community composition, 101 taxa out of 15 systematic groups have been documented. Specimens which are new for science (Acari), new for the fauna of Vietnam (Nematoda, etc.), and rare representatives of surface waters (Syncarida) are found. The largest part of taxonomic diversity is formed by Nematoda (38 taxa), Annelida (18), and Chironomidae (22). The same groups dominated in abundance. The taxonomic richness, abundance, and biomass of the community varied within 4–45 taxa, 3.8–161.9 thousand ind/m², and 0.05–2.2 g/m². In general, the type of changes of all parameters along the river profile was classical: the values increased from the upper mountain sections to the lower plain parts. The revealed pattern testifies to the important role that hydrodynamics play in the macroscale distribution of meiobenthos in the river during the period under study. The dependence that the community characteristics have on the local features of biotopes (microdistribution) is not as definite and requires an additional study of more extensive material.     

Mechanisms of ≡C---H bond activation in oxidative carbonylations of alkynes catalyzed by palladium complexes

Three types of catalytic system based on palladium complexes were studied in the synthesis of alkynylcarboxylic acid esters by oxidative carbonylation of monosubstituted alkynes. Three mechanisms were proposed for activation of the ≡C---H bond in alkynes and the formation of RC≡C[Pd]X, a key intermediate: (i) electrophilic substitution of H⁺ by Cu(I), (ii) electrophilic substitution of H⁺ by I⁺, and (iii) oxidative addition of the C---H bond in alkynes to palladium.