Acute exercise increases expression of extracellular superoxide dismutase in skeletal muscle and the aorta

Exercise dramatically increases oxygen consumption and causes oxidative stress. Superoxide dismutase (SOD) is important in the first-line defence mechanisms against oxidative stress. To investigate the effect of acute exercise on the expression of SOD, we examined the expression of mRNA for three SOD isozymes, in mice run on a treadmill to exhaustion. Six hours after exercise, the expression of extracellular SOD (EC-SOD) mRNA increased significantly in skeletal muscle and persisted for 24 h, whereas no change was observed for cytoplasmic and mitochondrial SOD mRNA. Moreover, acute exercise also induced EC-SOD mRNA in the aorta. These results suggest that a single bout of exercise is enough to augment the expression EC-SOD mRNA in skeletal muscle and the aorta, and may partly explain the beneficial effect of exercise.     

High-performance liquid chromatographic determination of short-chain aliphatic aldehydes using 4-(N,N-dimethylaminosulphonyl)-7-hydrazino-2,1,3-benzoxadiazole as a fluorescence reagent

High-performance liquid chromatographic determination of four short-chain aliphatic aldehydes using fluorescence detection was carried out with 4-(N,N-dimethylaminosulphonyl)-7-hydrazino-2,1,3-benzoxadiazole (DBD-H). DBD-H derivatives with three aliphatic aldehydes — formaldehyde, acetaldehyde and propionaldehyde — were synthesized and their fluorescence properties were examined. Relative fluorescence intensities of these compounds in acetonitrile were ca. ten-fold larger than those in aqueous acetonitrile. DBD-hydrazones could be separated by reversed-phase chromatography using aqueous acetonitrile as eluent and detection at 560 nm with excitation at 445 nm. Submicromolar levels of formaldehyde, acetaldehyde, propionaldehyde and butylaldehyde could be determined. The HPLC procedure using propionaldehyde as internal standard was applied to the measurement of acetaldehyde levels in normal human plasma before and 30 min after ingestion of ethanol.     

BACE1 modulates filopodia-like protrusions induced by sodium channel beta4 subunit

Processing of APP by BACE1 plays a crucial role in the pathogenesis of Alzheimer disease (AD). Recently, the voltage-gated sodium channel (Na_v) β4 subunit (β4), an auxiliary subunit of Na_v that is supposed to serve as a cell adhesion molecule, has been identified as a substrate for BACE1. However, the biological consequence of BACE1 processing of β4 remains illusive. Here, we report the biological effects of β4 processing by BACE1. Overexpression of β4 in Neuro2a cells promoted neurite extension and increased the number of F-actin rich filopodia-like protrusions. While coexpression of BACE1 together with β4 further accelerated neurite extension, the number of filopodia-like protrusions was reduced. Overexpression of C-terminal fragment of β4 that was generated by BACE1 (β4-CTF) partially recapitulated the results obtained with BACE1 overexpression. These results suggest that the processing of β4 by BACE1 regulates neurite length and filopodia-like protrusion density in neurons.     

Synthesis of 6-Sulfur Analogues of Oxanosine and Closely Related Derivatives Thereof

Abstract

Novel β-D-ribofuranosides having a 5-substituted imidazo [4,5-d] [1,3]thiazine ring, including the S⁶-congener 3 of oxanosine 2, were synthesized for screening their anticancer and antiviral activities.     

Development and characterization of 21 polymorphic microsatellite loci in the aphidophagous gall midge, <Emphasis Type="Italic">Aphidoletes aphidimyza</Emphasis> (Diptera: Cecidomyiidae)

We have developed and characterized 21 microsatellite markers in the aphidophagous gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). All 21 loci tested were polymorphic: the number of alleles ranged from 2 to 17. Allelic richness and observed heterozygosities were higher in females than in males. Several loci had no heterozygosity in males, suggesting that the loci were located on sex chromosomes or E-chromosomes, common to cecidomyiids. The high polymorphism detected in this study suggests the markers will be of value in analyzing genetic structure of field populations.     

Hydrophobic Components in Delipidated Granule of Egg Yolk

Dimethyl sulfide (DMS) is volatile compound important as one of the characteristic flavor compounds of marine food products. The precursor of DMS in marine products is dimethyl-β- propiothetin (DMPT), which is abundunt in green algae. DMPT was effectively extracted by the use of hydrophilic solvents from dried hitoegusa (Monostroma nitidum), a green alga. At around pH 4 and at over pH 9, the extracted DMPT was rapidly degraded to DMS; at around pH 7.5, this degradation was much slower. The DMS obtained volatilized immediately from aqueous solution. However, when the DMPT was formed into a powder with dextrin and heated to release the DMS, 40 — 60% of the DMS remained in the powder. The amount of DMS remaining was 80 % when cyclodextrin was used to form the powder.     

Kinetic Memory Based on the Enzyme-Limited Competition

Cellular memory, which allows cells to retain information from their environment, is important for a variety of cellular functions, such as adaptation to external stimuli, cell differentiation, and synaptic plasticity. Although posttranslational modifications have received much attention as a source of cellular memory, the mechanisms directing such alterations have not been fully uncovered. It may be possible to embed memory in multiple stable states in dynamical systems governing modifications. However, several experiments on modifications of proteins suggest long-term relaxation depending on experienced external conditions, without explicit switches over multi-stable states. As an alternative to a multistability memory scheme, we propose “kinetic memory” for epigenetic cellular memory, in which memory is stored as a slow-relaxation process far from a stable fixed state. Information from previous environmental exposure is retained as the long-term maintenance of a cellular state, rather than switches over fixed states. To demonstrate this kinetic memory, we study several models in which multimeric proteins undergo catalytic modifications (e.g., phosphorylation and methylation), and find that a slow relaxation process of the modification state, logarithmic in time, appears when the concentration of a catalyst (enzyme) involved in the modification reactions is lower than that of the substrates. Sharp transitions from a normal fast-relaxation phase into this slow-relaxation phase are revealed, and explained by enzyme-limited competition among modification reactions. The slow-relaxation process is confirmed by simulations of several models of catalytic reactions of protein modifications, and it enables the memorization of external stimuli, as its time course depends crucially on the history of the stimuli. This kinetic memory provides novel insight into a broad class of cellular memory and functions. In particular, applications for long-term potentiation are discussed, including dynamic modifications of calcium-calmodulin kinase II and cAMP-response element-binding protein essential for synaptic plasticity.     

High-dose zolpidem abuse in a patient with insomnia comorbid with major depressive disorder

Sleep and Biological Rhythms - A 39-year-old married woman was referred to a psychiatry outpatient clinic for treatment of major depressive disorder (MDD). The dose of zolpidem she had been taking...