Mitochondrial phospholipid hydroperoxide glutathione peroxidase suppresses apoptosis mediated by a mitochondrial death pathway.

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a key enzyme in the protection of biomembranes exposed to oxidative stress. We investigated the role of mitochondrial PHGPx in apoptosis using RBL2H3 cells that overexpressed mitochondrial PHGPx (M15 cells), cells that overexpressed non-mitochondrial PHGPx (L9 cells), and control cells (S1 cells). The morphological changes and fragmentation of DNA associated with apoptosis occurred within 15 h in S1 and L9 cells upon exposure of cells to 2-deoxyglucose (2DG). The release of cytochrome c from mitochondria was observed in S1 cells after 4 h and was followed by the activation of caspase-3 within 6 h. Overexpression of mitochondrial PHGPx prevented the release of cytochrome c, the activation of caspase-3, and apoptosis, but non-mitochondrial PHGPx lacked the ability to prevent the induction of apoptosis by 2DG. An ability to protect cells from 2DG-induced apoptosis was abolished when the PHGPx activity of M15 cells was inhibited by diethylmalate, indicating that the resistance of M15 cells to apoptosis was indeed due to the overexpression of PHGPx in the mitochondria. The expression of members of the Bcl-2 family of proteins, such as Bcl-2, Bcl-xL, Bax, and Bad, was unchanged by the overexpression of PHGPx in cells. The levels of hydroperoxides, including hydrogen and lipid peroxide, in mitochondria isolated from S1 and L9 cells were significantly increased after the exposure to 2DG for 2 h, while the level of hydroperoxide in mitochondria isolated from M15 cells was lower than that in S1 and L9 cells. M15 cells were also resistant to apoptosis induced by etoposide, staurosporine, UV irradiation, cycloheximide, and actinomycin D, but not to apoptosis induced by Fas-specific antibodies, which induces apoptosis via a pathway distinct from the pathway initiated by 2DG. Our results suggest that hydroperoxide, produced in mitochondria, is a major factor in apoptosis and that mitochondrial PHGPx might play a critical role as an anti-apoptotic agent in mitochondrial death pathways.     

Changes in plasma thyroid hormones, luteinizing hormone (LH), estradiol, progesterone and corticosterone of laying hens during a forced molt

1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather.     

Evaluation of the antimicrobial activity of methylglyoxal bis(guanylhydrazone) analogues, the inhibitors for polyamine biosynthetic pathway

Metabolic and antiproliferative effects of methylglyoxal bis(butylamidinohydrazone) (MGBB) and methylglyoxal bis(cyclopentylamidinohydrazone) (MGBCP), inhibitors for polyamine biosynthetic pathway, on Escherichia coli, Shigella sonnei, Aeromonas sobria, Aeromonas hydrophila and Vibrio cholerae were investigated. MGBB at the concentration of 100 mumol/l depleted intracellular putrescine and spermidine concentrations of E. coli to 25 and 20% of the controls, respectively, while MGBCP depressed their concentrations to 38 and 24%, respectively. In these polyamine-depleted E. coli cells the syntheses of RNA, DNA and protein decreased to 13, 54 and 29% of the control, respectively, with MGBB and to 23, 71 and 55%, respectively, with MGBCP. The minimum inhibitory concentrations (MIC) of MGBB for the growth of A. sobria, E. coli, A. hydrophila, V. cholerae and Sh. sonnei were estimated to be 50, 160, 240, 285 and 320 mumol/l, respectively, whereas those of MGBCP were slightly higher for respective bacteria.     

A macrophage receptor for liver lysosomal beta-glucosidase

beta-Glucosidase was purified from lysosomal membranes isolated from rat liver. Binding and uptake of the purified beta-glucosidase were mediated via an apparently single binding site on rat peritoneal macrophages. The number of sites and the Kd were 4.20 X 10(4)/cell and 1.00 X 10(-7) M, respectively. Neither of the processes was inhibited by ligands for mannose/fucose receptors, mannose 6-phosphate receptors, or scavenger receptors, or by other glycoproteins and sugar compounds. A portion of the beta-glucosidase taken up into the macrophages was degraded rapidly. These results suggested that liver lysosomal beta-glucosidase was endocytosed via a receptor not previously described.     

Alcohol dehydrogenase isozymes in the mouse: Genetic regulation, allelic variation among inbred strains and sex differences of liver and kidney A2 isozyme activity

Genetic analysis of a proposed cis-acting temporal locus ( Adh-3t ), which regulates alcohol dehydrogenase C₂ (ADH-C₂) acitivity in mouse epididymis extracts, among F₁ (ddN × BALB/c) × ddN male backcross progeny provided evidence for genetic distinctness between the structural ( Adh-3 ) and temporal ( Adh-3t ) loci on chromosome 3. Genetic analysis also confirmed the close, linkage of Adh-1 (encoding liver and kidney ADH-A₂) and Adh-3 (encoding stomach ADH-C₂) to within 0.3 centimorgans on the mouse genome. Evidence is presented for a proposed closely linked cis-acting temporal locus (designated Adh-1t ) for the A₂ isozyme (encoded by Adh-1 ) controlling the activity of this enzyme in mouse kidney extracts, but having no apparent affect on liver and intestine ADH-A₂ activities. An extensive survey of the distribution of Adh-1, Adh-3 and Adh-3t alleles among 65 strains of mice is reported — with the exception of two Japanese strains (ddN and KF), linkage disequilibrium between Adh-3 and Adh-3t was observed. Sex differences in mouse liver and kidney ADH-A₂ activities were observed, with male/female ratios of approximately 0.6 and 3 respectively for these tissue extracts.     

Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort

ABSTRACT

Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients.