Responses of Isolated Plant Mitochondria to Photosynthesis Inhibiting Acylanilides

During experiments to elucidate the mode of action of photosynthesis inhibiting acylanilide type herbicides, the effects of various acylanilides on respiration and oxidative phosphorylation of isolated plant mitochondria were studied. The results showed that some acylanilides acted as uncouplers of oxidative phosphorylation: 1) Some stimulated the ADP-limited state 4 respiration of isolated mitochondria depriving them of their respiratory control ability during succinate oxidation. 2) Those which stimulated state 4 respiration interfered with oxidative phosphorylation to degenerate the P/O ratio.

The following relationships between chemical structure of acylanilides and their biological activities were demonstrated: 3) Among various ring-chlorinated propionanilides, the activity of 3′,4′-DCPA was especially prominent. 4) Almost all the side chain-substituted 3′,4′-dichloroacylanilides tested were effective. 5) Both chlorination of the 3 and 4 positions of the aniline moiety and acylanilide bonding were simultaneously required for an acylanilide to produce uncoupling activity. 6) DCMU was less effective than was 3′,4′-DCPA, both in stimulating state 4 and in degenerating the P/O ratio.     

Reduction of glucose uptake through inhibition of hexose transporters and enhancement of their endocytosis by methylglyoxal in Saccharomyces cerevisiae

Diabetes mellitus is characterized by an impairment of glucose uptake even though blood glucose levels are increased. Methylglyoxal is derived from glycolysis and has been implicated in the development of diabetes mellitus, because methylglyoxal levels in blood and tissues are higher in diabetic patients than in healthy individuals. However, it remains to be elucidated whether such factors are a cause, or consequence, of diabetes. Here, we show that methylglyoxal inhibits the activity of mammalian glucose transporters using recombinant Saccharomyces cerevisiae cells genetically lacking all hexose transporters but carrying cDNA for human GLUT1 or rat GLUT4. We found that methylglyoxal inhibits yeast hexose transporters also. Glucose uptake was reduced in a stepwise manner following treatment with methylglyoxal, i.e. a rapid reduction within 5 min, followed by a slow and gradual reduction. The rapid reduction was due to the inhibitory effect of methylglyoxal on hexose transporters, whereas the slow and gradual reduction seemed due to endocytosis, which leads to a decrease in the amount of hexose transporters on the plasma membrane. We found that Rsp5, a HECT-type ubiquitin ligase, is responsible for the ubiquitination of hexose transporters. Intriguingly, Plc1 (phospholipase C) negatively regulated the endocytosis of hexose transporters in an Rsp5-dependent manner, although the methylglyoxal-induced endocytosis of hexose transporters occurred irrespective of Plc1. Meanwhile, the internalization of hexose transporters following treatment with methylglyoxal was delayed in a mutant defective in protein kinase C.     

Cloning of a rat glia maturation factor-gamma (rGMFG) cDNA and expression of its mRNA and protein in rat organs

We isolated a rat glia maturation factor-gamma(rGMFG) cDNA and examined the tissue distribution of GMFG in rat by Northern and Western blot analyses. Sequence analysis of the entire cDNA revealed an open reading frame of 426 nucleotides with a deduced protein of 142 amino acid residues. The deduced amino acid sequence of the putative product is highly homologous (78.9%) to rat glia maturation factor-beta (rGMFB). Northern blot analysis indicated that a 0.9-kb mRNA is predominantly expressed in rat thymus, testis, and spleen. GMFG showed a different tissue distribution from GMFB, being present predominantly in proliferative and differentiative organs.     

The Effect of Cork Pieces on Pseudohypericin Production in Cells ofHypericum perforatumShoots

The stimulating effect of cork pieces on hypericin and pseudohypericin biosyntheses was studied in cells of shoots regenerated from the callus cultures of St. John's wort (Hypericum perforatumL.). The addition of the cork matrix slightly stimulated shoot growth and enhanced pseudohypericin biosynthesis about threefold (to 0.4 mg/g dry wt). Pseudohypericin production increased proportionally with the amount of cork material added (from 1 to 4 mg/ml of growth medium). Further increase in the amount of cork pieces inhibited both pseudohypericin production and shoot growth. Organic and aqueous extracts of cork pieces did not affect the production of these substances.     

Role of C-terminal region of HA-33 component of botulinum toxin in hemagglutination.

Using SDS-PAGE, we found that one subcomponent, hemagglutinin (HA-33), from the Clostridium botulinum progenitor toxin of type D strain 1873 and type C strain Yoichi had slightly smaller molecular sizes than those of type C and D reference strains, but other components did not. Based on N- and C-terminal sequence analyses of HA-33, a deletion of 31 amino acid residues from the C-terminus at a specific site was observed in the HA-33 proteins of both strains. The progenitor toxins from both strains showed poor hemagglutination activities, titers of 2(1) or less, which were much lower than titers from the reference strains (2(6)), and did not bind to erythrocytes. These results suggest strongly that the short C-terminal region of the HA-33 plays an essential role in the hemagglutination activity of the botulinum progenitor toxin. Additionally, a sequence motif search predicted that the C-terminal region of HA-33 has a carbohydrate-recognition subdomain.     

Hepatic stellate cells contain the functional estrogen receptor beta but not the estrogen receptor alpha in male and female rats

In an earlier study, we showed that estradiol (E2) inhibits proliferation and transformation in cultured rat hepatic stellate cells (HSCs) and that the actions of E2 are mediated through estrogen receptors (ERs). This study reports on an investigation of the cellular localization of ER subtypes ERalpha and ERbeta using immunohistochemistry in experimental fibrotic liver rats and of each ER subtype expression in cultured rat HSCs by evaluating the produced mRNA and protein. The results indicate that high levels of ERbeta expression and low or no levels of ERalpha expression were observed in normal and fibrotic livers and in quiescent and activated HSCs from both males and females. The specificity of E2-mediated antiapoptotic induction through the ERbeta was shown by dose-dependent inhibition by the pure ER antagonist ICI 182,780 in HSCs which were undergoing early apoptosis. These findings demonstrate for the first time that rat HSCs possess functional Erbeta, but not Eralpha, to respond directly to E2 exposure.     

Efficacy of liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, on body weight, eating behavior, and glycemic control, in Japanese obese type 2 diabetes

ABSTRACT: BACKGROUND: We recently reported that short-term treatment with liraglutide (20.0 +/- 6.4 days) reduced body weight and improved some scales of eating behavior in Japanese type 2 diabetes inpatients. However, it remained uncertain whether such liraglutide-induced improvement is maintained after discharge from the hospital. The aim of the present study was to determine the long-term effects of liraglutide on body weight, glycemic control, and eating behavior in Japanese obese type 2 diabetics. METHODS: Patients with obesity (body mass index (BMI) >25 kg/m2) and type 2 diabetes were hospitalized at Osaka University Hospital between November 2010 and December 2011. BMI and glycated hemoglobin (HbA1c) were examined on admission, at discharge and at 1, 3, and 6 months after discharge. For the liraglutide group (BMI; 31.3 +/- 5.3 kg/m2, n = 29), patients were introduced to liraglutide after correction of hyperglycemic by insulin or oral glucose-lowering drugs and maintained on liraglutide after discharge. Eating behavior was assessed in patients treated with liraglutide using The Guideline For Obesity questionnaire issued by the Japan Society for the Study of Obesity, at admission, discharge, 3 and 6 months after discharge. For the insulin group (BMI; 29.1 +/- 3.0 kg/m2, n = 28), each patient was treated with insulin during hospitalization and glycemic control maintained by insulin after discharge. RESULTS: Liraglutide induced significant and persistent weight loss from admission up to 6 months after discharge, while no change in body weight after discharge was noted in the insulin group. Liraglutide produced significant improvements in all major scores of eating behavior questionnaire items and such effect was maintained at 6 months after discharge. Weight loss correlated significantly with the decrease in scores for recognition of weight and constitution, sense of hunger, and eating style. CONCLUSION: Liraglutide produced meaningful long-term weight loss and significantly improved eating behavior in obese Japanese patients with type 2 diabetes.     

Hydrogen production by termite gut protists: characterization of iron hydrogenases of Parabasalian symbionts of the termite Coptotermes formosanus

Cellulolytic flagellated protists in the guts of termites produce molecular hydrogen (H(2)) that is emitted by the termites; however, little is known about the physiology and biochemistry of H(2) production from cellulose in the gut symbiotic protists due to their formidable unculturability. In order to understand the molecular basis for H(2) production, we here identified two genes encoding proteins homologous to iron-only hydrogenases (Fe hydrogenases) in Pseudotrichonympha grassii, a large cellulolytic symbiont in the phylum Parabasalia, in the gut of the termite Coptotermes formosanus. The two Fe hydrogenases were phylogenetically distinct and had different N-terminal accessory domains. The long-form protein represented a phylogenetic lineage unique among eukaryotic Fe hydrogenases, whereas the short form was monophyletic with those of other parabasalids. Active recombinant enzyme forms of these two Fe hydrogenases were successfully obtained without the specific auxiliary maturases. Although they differed in their extent of specific activity and optimal pH, both enzymes preferentially catalyzed H(2) evolution rather than H(2) uptake. H(2) evolution, at least that associated with the short-form enzyme, was still active even under high hydrogen partial pressure. H(2) evolution activity was detected in the hydrogenosomal fraction of P. grassii cells; however, the vigorous H(2) uptake activity of the endosymbiotic bacteria compensated for the strong H(2) evolution activity of the host protists. The results suggest that termite gut symbionts are a rich reservoir of novel Fe hydrogenases whose properties are adapted to the gut environment and that the potential of H(2) production in termite guts has been largely underestimated.