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61.
Bennoun P 《Photosynthesis research》2002,73(1-3):273-277
The present model of chlororespiration deals with the dark reduction and oxidation of plastoquinone. Both stages are reviewed
here for algae and higher plants. Recent data confirm the presence of a plastoquinone:oxygen oxidoreductase with features
different from those of the mitochondrial oxidases. The possible involvement of the chloroplast oxidase in the pathway of
carotenoid biosynthesis is discussed in view of various experimental data and on energetics considerations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
62.
Xanthophylls are oxygenated carotenoids that perform critical roles in plants. -carotene hydroxylases (-hydroxylases) add hydroxyl groups to the -rings of carotenes and have been cloned from several bacteria and plants, including Arabidopsis. The lut1 mutation of Arabidopsis disrupts -ring hydroxylation and has been suggested to identify a related carotene hydroxylase that functions specifically on -ring structures. We have used library screening and genomics-based approaches to isolate a second -hydroxylase genomic clone and its corresponding cDNA from Arabidopsis. The encoded protein is 70% identical to the previously reported Arabidopsis -hydroxylase 1. Phylogenetic analysis indicates a common origin for the two proteins, however, their different chromosomal locations, intron positions and intron sizes suggest their duplication is not recent. Although both hydroxylases are expressed in all Arabidopsis tissues analyzed, -hydroxylase 1 mRNA is always present at higher levels. Both cDNAs encode proteins that efficiently hydroxylate the C-3 position of -ring containing carotenes and are only weakly active towards -ring containing carotenes. Neither -hydroxylase cDNA maps to the LUT1 locus, and the genomic region encompassing the LUT1 locus does not contain a third related hydroxylase. These data indicate that the LUT1 locus encodes a protein necessary for -ring hydroxylation but unrelated to -hydroxylases at the level of amino acid sequence. 相似文献
63.
Merete Grung Frances M. L. D'Souza Michael Borowitzka Synnøve Liaaen-Jensen 《Journal of applied phycology》1992,4(2):165-171
Aplanospores ofHaematococcus pluvialis MUR 145 contained 0.7% carotenoids (dry wt. basis) consisting of β,β-carotene (5% of total carotenoid), echinenone (4%),
canthaxanthin (4%), (3S,3′S)-astaxanthin diester (34%), (3S,3′S)-astaxanthin monoester (46%), (3S,3′S)-astaxanthin (1%) and (3R,3′R,6′R)-lutein (6%).
The astaxanthin esters were examined by TLC and HPLC and VIS,1H NMR and mass spectra recorded. Their chirality was determined by the camphanate method (Vecchi & Müller, 1979) after anaerobic
hydrolysis.
The tough cell wall of the aplanospores required enzymatic treatment prior to pigment extraction. The potential use of this
microalga as a feed ingredient in aquaculture is discussed briefly. 相似文献
64.
In the current study, the improved oral bioavailability of a synthetic astaxanthin derivative (CardaxTM; disodium disuccinate astaxanthin) was utilized to evaluate its potential effects as a cardioprotective agent after 7-day
subchronic oral administration as a feed supplement to Sprague-Dawley rats. Animals received one of two concentrations of
CardaxTM in feed (0.1 and 0.4%; ∼125 and 500 mg/kg/day, respectively) or control feed without drug for 7 days prior to the infarct
study carried out on day 8. Thirty minutes of occlusion of the left anterior descending (LAD) coronary artery was followed
by 2 h of reperfusion prior to sacrifice, a regimen which resulted in a mean infarct size (IS) as a percentage (%) of the
area at risk (AAR; IS/AAR,%) of 61 ± 1.8%. The AAR was quantified by Patent blue dye injection, and IS was determined by triphenyltetrazolium
chloride (TTC) staining. CardaxTM at 0.1 and 0.4% in feed for 7 days resulted in a significant mean reduction in IS/AAR,% to 45 ± 2.0% (26% salvage) and 39
± 1.5% (36% salvage), respectively. Myocardial levels of free astaxanthin achieved after 7-day supplementation at each of
the two concentrations (400 ± 65 nM and 1634 ± 90 nM, respectively) demonstrated excellent solid-tissue target organ loading
after oral supplementation. Parallel trends in reduction of plasma levels of multiple lipid peroxidation products with disodium
disuccinate astaxanthin supplementation were observed, consistent with the documented in vitro antioxidant mechanism of action. These results extend the potential utility of this compound for cardioprotection to the
elective human cardiovascular patient population, for which 7-day oral pre-treatment (as with statins) provides significant
reductions in induced periprocedural infarct size. 相似文献
65.
Kerfeld CA 《Photosynthesis research》2004,81(3):215-225
The orange carotenoid protein (OCP) and its derivative, the red carotenoid protein (RCP), appear to play important photoprotective roles in cyanobacteria. Structural and functional characterization is gradually elucidating the specific details of how carotenoid-protein interactions, including the role of six methionine residues oriented toward the pigment, contribute to the spectral and functional properties of these proteins. 相似文献
66.
A green mutant was obtained among the chemically induced mutants of Rhodobacter sphaeroides 601 (RS601) and named GM309. A blue shift of 20 nm of the carotenoid absorption spectrum was found in the light-harvesting
complex II (LH2) of GM309. Different from LH2 of RS601, it was found that the carotenoids in GM309-LH2 changed to be neurosporene
by mutation. Neurosporene lacks a conjugate double bond, compared with the spheroidene in RS601-LH2 which has ten conjugate
double bonds. As shown by absorption and circular dichroism spectroscopy, the overall structure of GM309-LH2 is little affected
by this change. From fluorescence emission spectra, it is found that GM309-LH2 can transfer energy from carotenoids to Bchl-B850
without any change in efficiency. But the efficiency of energy transfer from B800 to B850 in GM309-LH2 is decreased to be
42% of that of the native. This work would provide a novel method to investigate the mechanism of excitation energy transfer
in LH2. 相似文献
67.
Jin-Hong?KimEmail author Myung-Hwa?Baek Byung?Yeoup?Chung Seung?Gon?Wi Jae-Sung?Kim 《Journal of Plant Biology》2004,47(4):314-321
To characterize the stimulatory effects of low-dose gamma radiation on early plant growth, we investigated alterations in
the photosynthesis and antioxidant capacity of red pepper (Capsicum annuum L.) seedlings produced from gamma-irradiated seeds. For two cultivars (Yeomyung and Joheung), three irradiation groups (2,
4, and 8 Gy, but not 16 Gy) showed enhanced development, although Fv/Fm, the maximum photochemical efficiency of Photosystem
II (PSII), did not differ significantly among any of the four groups. In contrast, values for 1/Fo — 1/Fm, i.e., a measure
of functional PSII content, decreased in the irradiated groups of ‘Yeomyung’ but increased in those of ‘Joheung’. Pigment
analyses and enzyme activity assays revealed that irradiation altered the compositions of photosynthetic pigments (chlorophylls
and carotenoids) as well as the activities of antioxidant enzymes (superoxide dismutase and glutathione reductase). However,
these shifts were not directly related to the increase in early growth, although they were cultivar-and developmental stage-dependent
In addition, the effects of irradiation on the enzymatic activities measured here were at opposition between the two cultivars. 相似文献
68.
Sodium chloride induced changes in leaf growth, and pigment and protein contents in two rice cultivars 总被引:2,自引:0,他引:2
A.N. Misra S.M. Sahu M. Misra P. Singh I. Meera N. Das M. Kar P. Sahu 《Biologia Plantarum》1997,39(2):257-262
Rice (Oryza sativa L.) seedlings were grown under NaCl stress. The leaf growth of resistant cv. Damodar was less affected
than that of the susceptible cv. Jaya. The leaf protein content showed no distinct cultivar or age dependent differences under
NaCl salinity. There was a significant increase in chlorophyll (Chl) and carotenoid (Car) contents of 25-d-oldseedlings of
both cv. Jaya and cv. Damodar. However, Chl and Car content of 15-d-old seedlings of cv. Jaya decreased and that of cv. Damodar
increased, under NaCl stress.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
69.
The factors controlling biomass production and the synthesis of astaxanthin esters in the microalga Haematococcus pluvialis (CCAP 34/7) have been investigated using a statistical approach employing response surface methodology (RSM). The culture
conditions required for optimal growth and carotenogenesis in this alga are very different. Of particular importance is the
photon flux density: for growth the optimum is 50–60 μmol m−2 s−1 whereas the optimum for astaxanthin synthesis is much higher at ∼-1600 μmol m−2 s−1. The addition of low levels of NaCl to the medium also stimulates to a small extent synthesis of astaxanthin, but photon
flux density remains the overriding factor. The optimal temperature for this strain is quite low at 14–15 °C. RSM has been
shown to be a rapid and effective technique leading to the optimisation of algal culture conditions. This statistical approach
can be applied readily to the majority of microalgae and their products. 相似文献
70.
HPLC-analysis of algal pigments: comparison of columns,column properties and eluents 总被引:1,自引:0,他引:1
The effects of columns (Nucleosil C18ODS, MZ-PAH, YMC-PACK C30), column properties (inner diameters of 4 mm, 3 mm and 2 mm, pore-width 10 nm and 30 nm) and eluents (methanol, acetonitrile,
acetone, water) were tested on the separation of algal pigments. The length of columns was 250 mm and particle size was 5
μm. Flow rates and gradients were adjusted to optimize peak separation; remaining chromatographic conditions were kept constant.
The resolution of chromatographic systems was tested with pigment standards and various algal cultures. Total flow rate and
retention times decreased with decreasing inner diameter, whereas pressure, sensitivity and peak-width increased. Pore width
had negligible effects on the chromatographic separation of pigments under the test conditions. Only with acetonitrile as
eluent were all the taxonomically important pigments resolved adequately: zeaxanthin (Cyanophyceae), lutein (Chlorophyceae),
fucoxanthin (Bacillariopyceae), alloxanthin (Cryptophyceae), peridinin (Dinophyceae). 相似文献