Selective extraction of astaxanthin and chlorophyll from the green alga Haematococcus pluvialis

As astaxanthin could not be extracted with various organic solvents from intact thick-walled cyst cells of Haematococcus pluvialis, cells were held in 40% (v/v) acetone for 2 min at 80°C, followed by lyophilization or treatment of cells with specific lytic enzymes. By these treatments, 70% of the astaxanthin was extracted from the cells. Furthermore, the heat-acetone treatment was useful to remove chlorophyll specifically from the cells, contrary to saponification.     

An antioxidant treatment potentially protects myocardial energy metabolism by regulating uncoupling protein 2 expression in a chronic beta-adrenergic stimulation rat model

Excessive beta-adrenergic stimulation causes cardiac toxicity, which also contributes to cardiac oxidative stress. Although uncoupling protein 2 (UCP2), a member of the mitochondrial inner membrane carrier family, can regulate energy efficiency and oxidative stress in mitochondria, little data exist regarding interactions between UCP2 expression and beta-adrenergic stimulation induced cardiac oxidative damage. We investigated whether chronic beta-adrenergic stimulation induces myocardial energy metabolism abnormality via oxidative stress, including any role of UCP2. We also examined whether 3-methyl-1-phenyl-2-pyrazolin-5-one (MIC-186; edaravone), a potent free radical scavenger, has cardioprotective effects against beta-adrenergic stimulation. Male Sprague-Dawley rats received isoproterenol (1.2 mg/kg/day) subcutaneously or/and edaravone (30 mg/kg/day) orally. Isoproterenol increased the heart/body weight ratio, accompanied by an increase in the level of myocardial thiobarbituric acid reactive substances (TBARS) and a decreased phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. Isoproterenol also markedly increased expressions of UCP2 mRNA (1.74 fold vs. non-isoproterenol) and protein (1.93 fold vs. non-isoproterenol). Edaravone had no apparent effect in hypertrophic responses, but significantly prevented both increases in TBARS and decreases in the PCr/ATP ratio. Edaravone also prevented increases in UCP2 mRNA (0.76 fold vs. isoproterenol) and protein (0.62 fold vs. isoproterenol) expressions against isoproterenol administration. Our results suggest that chronic beta-adrenergic stimulation induces myocardial energy inefficiency via excessive oxidative stress. The antioxidant effect of edaravone has potential to improve energy metabolism abnormalities against beta-adrenergic stimulation. Adequate regulation of UCP2 expression through artificial reduction of oxidative stress may play an important role in protection of the myocardial energy metabolism.     

Change of subunit composition of mitochondrial complex II (succinate-ubiquinone reductase/quinol-fumarate reductase) in Ascaris suum during the migration in the experimental host

The mitochondrial metabolic pathway of the parasitic nematode Ascaris suum changes dramatically during its life cycle, to adapt to changes in the environmental oxygen concentration. We previously showed that A. suum mitochondria express stage-specific isoforms of complex II (succinate-ubiquinone reductase: SQR/quinol-fumarate reductase: QFR). The flavoprotein (Fp) and small subunit of cytochrome b (CybS) in adult complex II differ from those of infective third stage larval (L3) complex II. However, there is no difference in the iron-sulfur cluster (Ip) or the large subunit of cytochrome b (CybL) between adult and L3 isoforms of complex II. In the present study, to clarify the changes that occur in the respiratory chain of A. suum larvae during their migration in the host, we examined enzymatic activity, quinone content and complex II subunit composition in mitochondria of lung stage L3 (LL3) A. suum larvae. LL3 mitochondria showed higher QFR activity ( approximately 160 nmol/min/mg) than mitochondria of A. suum at other stages (L3: approximately 80 nmol/min/mg; adult: approximately 70 nmol/min/mg). Ubiquinone content in LL3 mitochondria was more abundant than rhodoquinone ( approximately 1.8 nmol/mg versus approximately 0.9 nmol/mg). Interestingly, the results of two-dimensional bule-native/sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses showed that LL3 mitochondria contained larval Fp (Fp(L)) and adult Fp (Fp(A)) at a ratio of 1:0.56, and that most LL3 CybS subunits were of the adult form (CybS(A)). This clearly indicates that the rearrangement of complex II begins with a change in the isoform of the anchor CybS subunit, followed by a similar change in the Fp subunit.     

Mechanism of Benzyladenine-Induced Stimulation of the Synthesis of 5-Aminolevulinic Acid in Greening Cucumber Cotyledons: Benzyladenine Increases Levels of Plastid tRNAGlu

The mechanism of the stimulatory effect of a cytokinin, namely,benzyladenine (BA), on the synthesis of 5-aminolevulinic acid(ALA) in cucumber cotyledons was studied. The rate of synthesisof ALA by plastids isolated from BA-treated cotyledons was twicethat by plastids from untreated controls. Western blot analysisof stromal proteins showed that BA did not affect the levelof glutamyl-tRNA synthetase or of glutamate l-semialdehyde (GSA)aminotransferase. Analysis of free amino acids revealed thatBA did not increase the level of glutamate in the stroma. However,the amount of total plastidic RNA was doubled in BA-treatedcotyledons. Northern blot analysis showed that the level ofplastid tRNA^Glu was increased by treatment with BA to the sameextent as that of another plastid tRNA, reflecting an increasein total plastidic RNA. The rate of formation of glutamyl-tRNAwas also doubled in plastids from BA-treated cotyledons. Theresults indicate that stimulation of the synthesis of ALA byBA is due to an increased level of tRNA^Glu in plastids. (Received June 6, 1993; Accepted November 26, 1993)     

Pigment epithelium-derived factor (PEDF) prevents advanced glycation end products (AGEs)-elicited endothelial nitric oxide synthase (eNOS) reduction through its anti-oxidative properties

PEDF is an effective inhibitor of angiogenesis in the eye with neuronal differentiating activity. Here, we show that PEDF prevents the AGEs-elicited eNOS reduction through its anti-oxidative properties. Our present study suggests that PEDF may also play a protective role against atherosclerosis.     

Action spectrum for light-induced formation of adventitious shoots in hairy roots of horseradish

An action spectrum was determined for lightinduced formation of adventitious shoots in hairy roots of horseradish (Armoracia rusticana Gaert., Mey. et Scherb.) cultured in vitro. Near ultraviolet (350–400 nm), blue (440–460 nm) and red light (600–680 nm) were most effective in inducing formation of adventitious buds. Farred light (730 nm) inhibited the promotive effect of all three wavelength regions. These results are consistent with induction by phytochrome(s) of adventitious shoots in hairy roots of horseradish.     

Growth Competition between W Mutant and Wild-type Cells in Mouse Aggregation Chimeras

The dominant spotting (W) locus of the mouse has been demonstrated to be identical with the c-kit proto-oncogene. The c-kit is strongly expressed in hematopoietic organs and the brain of mice. In homozygotes and double heterozygotes of the W mutant alleles (hereafter W mutant), development of erythrocytes, mast cells, melanocytes and germ cells is deficient. The deficiency of erythrocytes, mast cells and melanocytes is attributed to a defect of precursor cells, but the cause of the germ cell deficiency is not clear. We investigated the effect of the W mutation on proliferative potential of cells composing various organs by examining aggregation chimeras between W mutant and wild-type (+/+) embryos. Proportions of +/+ components were significantly greater in the male germ cells and hematopoietic cells. In contrast, the average proportions of +/+ components were comparable to those of W mutant components in other organs including the brain. The present result suggests that the W (c-kit ) gene plays an important role in development of the male germ cells and hematopoietic cells and that it does not promote the proliferation of major cell population in the brain, in spite of the strong expression of the W (c-kit ) gene in the brain.