Corticoliberin fragment CRF4-6 modifies rat behavior in opposite ways under stressing and non-stressing conditions

The effects of tripeptide corticoliberin fragment CRF4-6 (icv; 6, 30, and 150 nmol/head) on behaviour of rats were investigated under non-stressing and stressing conditions. CRF4-6 activated rat behaviour under non-stressing conditions (home cage): the duration of locomotion and exploratory behaviour was increased whereas the duration of passive behaviour and sleep was decreased. On the other hand, CRF4-6 suppressed the rat exploratory behaviour under stressing conditions (elevated plus-maze): the duration of non-exploratory behaviour was increased; numbers of rearings and leanings out to open arms were reduced. All observed effects of the tripeptide CRF4-6 were dose-dependent. Behavioural effects of the tripeptide were similar to the well-known action of the whole corticoliberin molecule. Therefore we suggest that CRF4-6 is located in the active part of CRF or it can be a physiologically active corticoliberin derivative.     

Peculiarities of metabolism and functions of high-molecular inorganic polyphosphates in yeasts as representatives of lower eukaryotes

The review presents the recent data demonstrating the important role high-molecular inorganic polyphosphates in regulatory processes in a yeast cell. It has been shown that polyphosphates are localized in different cell compartments, where they are metabolized by a special set of enzymes. The review presents the evidence in favor of the concept of multiple functions of these biopolymers in a cell, as well as the data on the pleiotropic effects of mutations in the genes encoding the enzymes of polyphosphate metabolism.     

Structurally conserved interaction of Lgl family with SNAREs is critical to their cellular function

The Lethal giant larvae (Lgl) tumor suppressor family is conserved from yeast to mammals and plays a critical yet controversial role in cell polarity. Studies on Drosophila Lgl suggest that its function in polarity is through regulation of the acto-myosin cytoskeleton. In contrast, studies on the yeast Lgl homologs, Sro7/Sro77, suggest a function in exocytosis through interaction with the t-SNARE Sec9. Using yeast/mammalian Lgl chimeras, we demonstrate that the overall architecture of Lgl proteins is highly conserved and that the C-terminal domain is the major site of SNARE interaction within both yeast and mammalian homologs. Importantly, we find that the ability of Lgl chimeras to function as the only source of Lgl in yeast correlates precisely with the ability to interact with the yeast t-SNARE. We report a novel interaction between Sro7 and the yeast myosin V, Myo2. However, we find that interactions with either Myo2 or Myo1 (myosin II) cannot account for the dramatic functional differences observed for these chimeras in yeast. These results provide the first demonstration that the interaction of an Lgl family member with a specific effector is critical to its function in vivo. These data support the model that the Lgl family functions in cell polarity, at least in part, by regulating SNARE-mediated membrane delivery events at the cell surface.     

Purification and cytotoxic properties of Bacillus cereus hemolysin II

The hemolysin II from Bacillus cereus, HlyII, is a member of the beta-barrel pore-forming toxin family of secreted microbial proteins that includes the Staphylococcus aureus alpha-toxin. Compared with other proteins of the family, hemolysin II has 90 extra amino acids at its C-terminus. To examine more closely the cytotoxic and pore-forming properties of the protein, we have cloned and expressed it in Escherichia coli. We developed a purification procedure for the matured HlyII protein from both culture media and cell extracts using a combination of cation exchange and affinity chromatography together with gel-filtration. In both cases, the fully processed HlyII protein was purified as confirmed by N-terminal sequence analysis. The HlyII protein exhibits cytolytic activity of different extent on erythrocytes from various kinds of mammals. The results presented here show for the first time that two types of human cells are sensitive to HlyII action. In view of its broad cytotoxic activity as well as the ability to interact with artificial membranes, we assume that HlyII needs no specific receptor to bind to cell membranes.     

Evenly tritium-labeled peptides and their in vivo and in vitro biodegradation

Biologically active peptides evenly labeled with tritium were used for studying the in vitro and in vivo biodegradation of the peptides. Tritium-labeled peptides with a specific radioactivity of 50-150 Ci/mmol were obtained by high temperature solid phase catalytic isotope exchange (HSCIE) with spillover tritium. The distribution of the isotope label among all amino acid residues of these peptides allows the simultaneous determination of practically all possible products of their enzymatic hydrolysis. The developed analytical method includes extraction of tritium-labeled peptides from organism tissues and chromatographic isolation of individual labeled peptides from the mixture of degradation products. The concentrations of a peptide under study and the products of its biodegradation were calculated from the results of liquid scintillation counting. This approach was used for studying the pathways of biodegradation of the heptapeptide TKPRPGP (Selank) and the tripeptide PGP in blood plasma. The pharmacokinetics of Selank, an anxiolytic peptide, was also studied in brain tissues using the intranasal in vivo administration of this peptide. The concentrations of labeled peptides were determined, and the pentapeptide TKPRP, tripeptide TKP, and dipeptides RP and GP were shown to be the major products of Selank biodegradation. The study of the biodegradation of the heptapeptide MEHFPGP (Semax) in the presence of nerve cells showed that the major products of its biodegradation are the pentapeptide HFPGP and tripeptide PGP. The enkephalinase activity of blood plasma was studied with the use of evenly tritium-labeled [Leu]enkephalin. A high inhibitory effect of Semax on blood plasma enkephalinases was shown to arise from its action on aminopeptidases. The method, based on the use of evenly tritium-labeled peptides, allows the determination of peptide concentrations and the activity of enzymes involved in their degradation on a tg scale of biological samples both in vitro and in vivo.     

Cross-Sectional and Longitudinal Associations of Different Sedentary Behaviors with Cognitive Performance in Older Adults

Background

The deleterious health effects of sedentary behaviors, independent of physical activity, are increasingly being recognized. However, associations with cognitive performance are not known.

Purpose

To estimate the associations between different sedentary behaviors and cognitive performance in healthy older adults.

Methods

Computer use, time spent watching television (TV), time spent reading and habitual physical activity levels were self-reported twice (in 2001 and 2007) by participants in the SUpplémentation en Vitamines et MinérauX (SU.VI.MAX and SU.VI.MAX2) study. Cognitive performance was assessed at follow-up (in 2007–2009) via a battery of 6 neuropsychological tests used to derive verbal memory and executive functioning scores. Analyses (ANCOVA) were performed among 1425 men and 1154 women aged 65.6±4.5 at the time of the neuropsychological evaluation. We estimated mean differences with 95% confidence intervals (95%CI) in cognitive performance across categories of each type of sedentary behavior.

Results

In multivariable cross-sectional models, compared to non-users, participants using the computer for >1 h/day displayed better verbal memory (mean difference = 1.86; 95%CI: 0.95, 2.77) and executive functioning (mean difference = 2.15; 95%CI: 1.22, 3.08). A negative association was also observed between TV viewing and executive functioning. Additionally, participants who increased their computer use by more than 30 min between 2001 and 2007 showed better performance on both verbal memory (mean difference = 1.41; 95%CI: 0.55, 2.27) and executive functioning (mean difference = 1.41; 95%CI: 0.53, 2.28) compared to those who decreased their computer use during that period.

Conclusion

Specific sedentary behaviors are differentially associated with cognitive performance. In contrast to TV viewing, regular computer use may help maintain cognitive function during the aging process.

Clinical Trial Registration

clinicaltrial.gov (number {"type":"clinical-trial","attrs":{"text":"NCT00272428","term_id":"NCT00272428"}}NCT00272428).     

The summation properties of the somatosensory system demonstrated via a study of the tactile sensations evoked by an electrical current and by focused ultrasound

Sensational thresholds of the skin of fingers, palm and forearm have been determined in 5 healthy subjects ageing from 20 to 49 years. About 100 summation curves were obtained. Critical duration of the electrical stimuli remained constant in various areas. Critical duration of ultrasonic stimulation increased from fingers to forearm. The data obtained together with those found in literature suggest that critical duration of the stimulus is associated with the diameter of nonmyelin nervous fibers which are affected by the stimulus increasing with the increase in fiber diameter.     

Immunochemical properties of erythrocyte-specific histone H5 in salmonid fishes

Comparative studies have been made on the immunochemical properties of histone H5 in Salmonidae species. High degree of homology between these histones and H5 histone from Oncorhynchus tschawytscha was demonstrated by microcomplement fixation. Properties of H5 histones in fish and birds are discussed.     

New data on the type of structural changes in DNA of simian adenovirus SA7 microinjected into mouse zygotes

The structure of the transgene has been analysed in a new series of experiments on the transfer of adenovirus SA7 DNA into the mice zygotes by microinjection technique. The previous data on SA7 DNA elimination from the genomes of different organs (sceletal muscles, heart, tail) have been confirmed and detailed for the F0 and F1 generations of transgenic animals. The left end of adenoviral genome has been shown to be predominantly transfered after microinjections of SA7 DNA into the mice zygotes.