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1.
The amphibious leafless sedge Eleocharis retroflexa ssp. chaetaria expresses C4-like biochemical characteristics in both the terrestrial and submerged forms. Culms of the terrestrial form have Kranz anatomy, whereas those of the submerged form have Kranz-like anatomy combined with anatomical features of aquatic plant leaves. We examined the immunolocalization of C3 and C4 enzymes in culms of the two forms. In both forms, phosphoenolpyruvate carboxylase; pyruvate, Pi dikinase; and NAD-malic enzyme were compartmentalized between the mesophyll (M) and Kranz cells, but their levels were somewhat reduced in the submerged form. In the terrestrial form, ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) occurred mainly in the Kranz cells, and weakly in the M chloroplasts. In the submerged form, the rubisco occurred at higher levels in the M cells than in the terrestrial form. In both forms, the C4 pattern of enzyme expression was clearer in the M cells adjacent to Kranz cells than in distant M cells. During the transition from terrestrial to submerged conditions, the enzyme expression pattern changed in submerged mature culms that had been formed in air before submergence, and matched that in culms newly developed underwater. It seems that effects of both environmental and developmental factors overlap in the C4 pattern expression in this plant. 相似文献
2.
Increase in both atmospheric CO2 concentration [CO2] and associated warming are likely to alter Earths’ carbon balance and photosynthetic carbon fixation of dominant plant species
in a given biome. An experiment was conducted in sunlit, controlled environment chambers to determine effects of atmospheric
[CO2] and temperature on net photosynthetic rate (P
N) and fluorescence (F) in response to internal CO2 concentration (C
i) and photosynthetically active radiation (PAR) of the C4 species, big bluestem (Andropogon gerardii Vitman). Ten treatments were comprised of two [CO2] of 360 (ambient, AC) and 720 (elevated, EC) μmol mol−1 and five day/night temperature of 20/12, 25/17, 30/22, 35/27 and 40/32 °C. Treatments were imposed from 15 d after sowing
(DAS) through 130 DAS. Both F-P
N/C
i and F-P
N/PAR response curves were measured on top most fully expanded leaves between 55 and 75 DAS. Plants grown in EC exhibited significantly
higher CO2-saturated net photosynthesis (P
sat), phosphoenolpyruvate carboxylase (PEPC) efficiency, and electron transport rate (ETR). At a given [CO2], increase in temperature increased P
sat, PEPC efficiency, and ETR. Plants grown at EC did not differ for dark respiration rate (R
D), but had significantly higher maximum photosynthesis (P
max) than plants grown in AC. Increase in temperature increased Pmax, R
D, and ETR, irrespective of the [CO2]. The ability of PEPC, ribulose-1,5-bisphosphate carboxylase/oxygenase, and photosystem components, derived from response
curves to tolerate higher temperatures (>35 °C), particularly under EC, indicates the ability of C4 species to sustain photosynthetic capacity in future climates. 相似文献
3.
Clusia minor L. is a C3-CAM species in which Crassulacean acid Metabolism (CAM) is induced, among other factors, by water deficit. We propose that
CAM induction by natural drought in C. minor shifts the sap flow pattern from daytime to a night-time one, and that the decreased osmotic potential due to increased malate
content in droughted plants aids in the increase in nocturnal sap flow. In order to test these hypotheses, we followed for
2 years the seasonal changes in parameters of water relationships and sap flow velocity in one single, freestanding tree growing
in Caracas. Leaf water and osmotic potential were measured psychrometrically, nocturnal proton accumulation by titration of
aqueous leaf extracts and sap flow density with thermal dissipation probes. Leaf water, osmotic and turgor potential remained
relatively high throughout the seasons. Nocturnal proton accumulation was nil under extreme drought or after frequent and
heavy rains, and high after moderate rainfall. Estimated malate and citrate concentrations contributed up to 80 and 60%, respectively,
of the value of osmotic potential. The shape of the daily courses of sap flow velocity varied seasonally, from mostly diurnal
during the dry season to mostly nocturnal after a short dry spell during the rainy season, when nocturnal acid accumulation
attained high values. There was a strong positive relationship between the proportion of the integrated sap flow courses corresponding
to the night and dawn [H+] (r
2 = 0.88). Increased nocturnal sap flow in the CAM stage of the tree of C. minor may be explained by a lower osmotic potential due to an increased acid concentration, together with increased stomatal aperture,
as suggested by increased nocturnal acid accumulation probably due to nocturnal CO2 fixation. 相似文献
4.
In comparison with its wild type (WT), the transgenic (TG) rice with silenced OsBP-73 gene had significantly lower plant height, grain number per panicle, and leaf net photosynthetic rate (P
N). Also, the TG rice showed significantly lower chlorophyll (Chl), ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO),
RuBPCO activase, and RuBP contents, photosystem 2 (PS2) photochemical efficiency (Fv/Fm and ΔF/Fm′), apparent quantum yield of carbon assimilation (Φc), carboxylation efficiency (CE), photosynthetic electron transport and photophosphorylation rates as well as sucrose phosphate
synthase activity, but higher intercellular CO2 concentration, sucrose, fructose, and glycerate 3-phosphate contents, and non-photochemical quenching of Chl fluorescence
(NPQ). Thus the decreased P
N in the TG rice leaves is related to both RuBP carboxylation and RuBP regeneration limitations, and the latter is a predominant
limitation to photosynthesis. 相似文献
5.
Activities of some enzymes related to carbon metabolism were studied in different ecotypes of Rumex nepalensis growing at 1 300, 2 250, and 3 250 m above mean sea level. Activities of ribulose-1,5-bisphosphate carboxylase/oxygenase,
phosphoenolpyruvate carboxylase, aspartate aminotransferase, and glutamine synthetase increased with altitude, whereas activities of
malate dehydrogenase, NAD-malic enzyme, and citrate synthase did not show a significant difference with change in altitude. 相似文献
6.
Many bacteria adapt to microoxic conditions by synthesizing a particular cytochrome c oxidase (cbb
3) complex with a high affinity for O2, encoded by the ccoNOQP operon. A survey of genome databases indicates that ccoNOQP sequences are widespread in all sub-branches of Proteobacteria but otherwise are found only in bacteria of the CFB group (Cytophaga, Flexibacter, Bacteroides). Our analysis of available genome sequences suggests four major strategies of regulating ccoNOQP expression in response to O2. The most widespread strategy involves direct regulation by the O2-responsive protein Fnr. The second strategy involves an O2-insensitive paralogue of Fnr, FixK, whose expression is regulated by the O2-responding FixLJ two-component system. A third strategy of mixed regulation operates in bacteria carrying both fnr and fixLJ-fixK genes. Another, not yet identified, strategy is likely to operate in the -Proteobacteria Helicobacter pylori and Campylobacter jejuni which lack fnr and fixLJ-fixK genes. The FixLJ strategy appears specific for the -subclass of Proteobacteria but is not restricted to rhizobia in which it was originally discovered. 相似文献
7.
The kinetics of the ubiquinol-cytochrome c reductase reaction was examined using membrane fragments and purified bc(1) complexes derived from a wild-type (WT) and a newly constructed mutant (MUT) strains of Paracoccus denitrificans. The cytochrome c(1) of the WT samples possessed an additional stretch of acidic amino acids, which was lacking in the mutant. The reaction was followed with positively charged mitochondrial and negatively charged bacterial cytochromes c, and specific activities, apparent k(cat) values, and first-order rate constant values were compared. These values were distinctly lower for the MUT fractions using mitochondrial cytochrome c but differed only slightly with the bacterial species. The MUT preparations were less sensitive to changes of ionic strength of the reaction media and showed pure first-order kinetics with both samples of cytochrome c. The reaction of the WT enzyme was first order only with bacterial cytochrome c but proceeded with a non-linear profile with mitochondrial cytochrome c. The analysis of the reaction pattern revealed a rapid onset of the reaction with a successively declining rate. Experiments performed in the absence of an electron donor indicated that electrostatic attraction could directly participate in cytochrome c reduction. 相似文献
8.
Summary Coconut (Cocos nucifera L.) plantlets grown in vitro often grow slowly when transferred to the field possibly, due to a limited photosynthetic capacity of in vitro-cultured plantlets, apparently caused by the sucrose added to growth medium causing negative feedback for photosynthesis.
In this paper, we tested the hypothesis that high exogenous sucrose will decrease ribulose 1,5-bisphosphate carboxylase (Rubisco)
activity and photosynthesis resulting in limited ex vitro growth. Plantlets grown with high exogenous sucrose (90 gl−1) had reduced photosynthetic activity that resulted in a poor photosynthetic response to high levels of light and CO2. These plantlets also had low amounts of Rubisco protein, low Rubisco activity, and reduced growth despite showing high survival
when transferred to the field. Decreasing the medium’s sucrose concentration from 90 to 22.5 gl−1 or 0 gl−1 resulted in increased photosynthetic response to light and CO2 along with increased Rubisco and phosphoenolpyruvate carboxylase (PEPC) activities and proteins. However, plantlets grown
in vitro without exogenous sucrose died when transferred ex vitro, whereas those grown with intermediate exogenous sucrose showed intermediate photosynthetic response, high survival, fast
growth, and ex vitro photosynthesis. Thus, exogenous sucrose at moderate concentration decreased photosynthesis but increased survival, suggesting
that both in vitro photosynthesis and exogenous sucrose reserves contribute to field establisment and growth of coconut plantlets cultured in vitro. 相似文献
9.
Bienertia sinuspersici Akhani has an unusual mechanism of C4 photosynthesis which occurs within individual chlorenchyma cells. To perform C4, the mature cells have two cytoplasmic compartments consisting of a central (CCC) and a peripheral (PCC) domain containing
dimorphic chloroplasts which are interconnected by cytoplasmic channels. Based on leaf development studies, young chlorenchyma
cells have not developed the two cytoplasmic compartments and dimorphic chloroplasts. Fluorescent dyes which are targeted
to membranes or to specific organelles were used to follow changes in cell structure and organelle distribution during formation
of C4-type chlorenchyma. Chlorenchyma cell development was divided into four stages: 1—the nucleus and chloroplasts occupy much
of the cytoplasmic space and only small vacuoles are formed; 2—development of larger vacuoles, formation of a pre-CCC with
some scattered chloroplasts; 3—the vacuole expands, cells have directional growth; 4—mature stage, cells have become elongated,
with a distinctive CCC and PCC joined by interconnecting cytoplasmic channels. By staining vacuoles with a fluorescent dye
and constructing 3D images of chloroplasts, and by microinjecting a fluorescence dye into the vacuole of living cells, it
was demonstrated that the mature cell has only one vacuole, which is traversed by cytoplasmic channels connecting the CCC
with the PCC. Immunofluorescent studies on isolated chlorenchyma cells treated with cytoskeleton disrupting drugs suspended
in different levels of osmoticum showed that both microtubules and actin filaments are important in maintaining the cytoplasmic
domains. With prolonged exposure of plants to dim light, the cytoskeleton undergoes changes and there is a dramatic shift
of the CCC from the center toward the distal end of the cell. 相似文献
10.
Wenjuan Yao Xiaozhao Deng Hui Zhong Miao Liu Pu Zheng Zhihao Sun Yun Zhang 《Journal of industrial microbiology & biotechnology》2009,36(7):911-921
Corynebacterium glutamicum strains are used for the fermentative production of l-glutamate. Five C. glutamicum deletion mutants were isolated by two rounds of selection for homologous recombination and identified by Southern blot analysis.
The growth, glucose consumption and glutamate production of the mutants were analyzed and compared with the wild-type ATCC
13032 strain. Double disruption of dtsR1 (encoding a subunit of acetyl-CoA carboxylase complex) and pyc (encoding pyruvate carboxylase) caused efficient overproduction of l-glutamate in C. glutamicum; production was much higher than that of the wild-type strain and ΔdtsR1 strain under glutamate-inducing conditions. In the absence of any inducing conditions, the amount of glutamate produced by
the double-deletion strain ΔdtsR1Δpyc was more than that of the mutant ΔdtsR1. The activity of phosphoenolpyruvate carboxylase (PEPC) was found to be higher in the ΔdtsR1Δpyc strain than in the ΔdtsR1 strain and the wild-type strain. Therefore, PEPC appears to be an important anaplerotic enzyme for glutamate synthesis in
ΔdtsR1 derivatives. Moreover, this conclusion was confirmed by overexpression of ppc and pyc in the two double-deletion strains (ΔdtsR1Δppc and ΔdtsR1Δpyc), respectively. Based on the data generated in this investigation, we suggest a new method that will improve glutamate production
strains and provide a better understanding of the interaction(s) between the anaplerotic pathway and fatty acid synthesis. 相似文献
11.
Phosphoenolpyruvate carboxylase (EC 4.1.1.31) from Synechococcus vulcanus (SvPEPC) is a unique enzyme, being almost insensitive to feedback inhibition at neutral pH. In order to assess its usefulness in metabolic engineering of plants, SvPEPC was expressed in Arabidopsis thaliana (L.) Heynh. under the control of the cauliflower mosaic virus 35S promoter. About one-third of the transformants of the T1 generation showed severe visible phenotypes such as leaf bleaching and were infertile when grown on soil. However, no such phenotype was observed with Arabidopsis transformed with Zea mays L. PEPC (ZmPEPC) for C4 photosynthesis, which is normally sensitive to a feedback inhibitor, l-malate. For the SvPEPC transformants of the T2 generation, which had been derived from fertile T1 transformants, three kinds of phenotype were observed when plants were grown on an agar medium containing sucrose: Type-I plants showed poor growth and a block in true leaf development; Type-II plants produced a few true leaves, which were partially bleached; Type-III plants were apparently normal. In Type-I plants, total PEPC activity was increased about 2-fold over the control plant but there was no such increase in Type-III plants. The phenotypes of Type-I plants were rescued when the sucrose-containing agar medium was supplemented with aromatic amino acids. Measurement of the free amino acid content in whole seedlings of Type-I transformants revealed that the levels of the aromatic amino acids Phe and Tyr were lowered significantly as compared with the control plants. In contrast, the levels of several amino acids of the aspartic and glutamic families, such as Asn, Gln and Arg, were markedly enhanced (4- to 8-fold per plant fresh weight). However, when the medium was supplemented with aromatic amino acids, the levels of Asn, Gln, and Arg decreased to levels slightly higher than those of control plants, accompanied by growth recovery. Taken together, it can be envisaged that SvPEPC is capable of efficiently exerting its activity in the plant cell environment so as to cause imbalance between aromatic and non-aromatic amino acid syntheses. The growth inhibition of Type-I plants was presumed to be primarily due to a decreased availability of phosphoenolpyruvate, one of the precursors for the shikimate pathway for the synthesis of aromatic amino acids and phenylpropanoids. The possible usefulness of SvPEPC as one of the key components for installing the C4-like pathway is proposed.Abbreviations CaMV Cauliflower mosaic virus - GUS -Glucuronidase - Kan Kanamycin - 2-ME 2-Mercaptoethanol - MS/G medium 1/2 Murashige–Skoog and 1/2 Gamborg mixed medium - PEP Phosphoenolpyruvate - PEPC Phosphoenolpyruvate carboxylase - Sv Synechococcus vulcanus - ZmPEPC Maize PEPC involved in C4 photosynthesis 相似文献
12.
Hartung de Capriles C Mata-Essayag S Pérez C Colella MT Roselló A Olaizola C Abate SM 《Mycopathologia》2005,160(3):227-234
Over the past decades there has been a significant increase in fungal infections caused by Candida species, and continues to be common in immunocompromised individuals infected with the human immunodeficiency virus (HIV).
Although Candida albicans remains the fungal species most frequently isolated as an opportunistic oral pathogen, other non-albicans are often identified in this cohort of patients, including C. dubliniensis. This yeast is closely related to and shares many phenotypic characteristics with C. albicans. Colonies of these two species appear morphologically identical when not grown on special media. The shared phenotypic characteristics
of C. dubliniensis and C. albicans suggest that many C. dubliniensis isolates may have been misidentified as C. albicans in the past. The present studies aim is to recover and identify C. dubliniensis, and presumptive clinical C. albicans, from the oral cavities of HIV-seropositive individuals, comparing conventional media to obtain a simple, low-cost and reliable
identification system for C. dubliniensis. A total of 16 isolates (3,98%) had been obtained from 402 HIV infected individuals with recurrent oropharyngitis and were
identified as C. dubliniensis. Out of these C. dubliniensis isolates 19% were resistant, with MICs above 64 μg/ml to fluconazole. This constitutes, to the authors knowledge the first
recovery of this organism in Venezuela. 相似文献
13.
Maize (Zea mays L.) seedlings were grown in nutrient solution culture containing 0, 5, and 20 μM cadmium (Cd) and the effects on various
aspects of photosynthesis were investigated after 24, 48, 96 and 168 h of Cd treatments. Photosynthetic rate (P
N) decreased after 48 h of 20 μM Cd and 96 h of 5μM Cd addition, respectively. Chl a and total Chl content in leaves declined under 48 h of Cd exposure. Chl b content decreased on extending the period of Cd exposure to 96 h. The maximum quantum efficiency and potential photosynthetic
capacity of PSII, indicated by Fv/Fm and Fv/Fo, respectively, were depressed after 96 h onset of Cd exposure. After 48 h of 5μM Cd and 24 h of 20 μM Cd treatments, the
activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.39) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) in the leaves started to decrease, respectively. We found that the limitation of
photosynthetic capacity in Cd stressed maize leaves was associated with Cd toxicity on the light and the dark stages. However,
Cd stress initially reduced the activities of Rubisco and PEPC and subsequently affected the PSII electron transfer, suggesting
that the Calvin cycle reactions in maize plants are the primary target of the Cd toxic effect rather than PSII. 相似文献
14.
L-Lactate cytochrome c oxidoreductase (flavocytochrome b 2, FC b 2) from the thermotolerant methylotrophic yeast Hansenula polymorpha (Pichia angusta) is, unlike the enzyme form baker’s yeast, a thermostable enzyme potentially important for bioanalytical technologies for highly selective assays of L-lactate in biological fluids and foods. This paper describes the construction of flavocytochrome b 2 producers with over-expression of the H. polymorpha CYB2 gene, encoding FC b 2. The HpCYB2 gene under the control of the strong H. polymorpha alcohol oxidase promoter in a plasmid for multicopy integration was transformed into the recipient strain H. polymorpha C-105 (grc1 catX), impaired in glucose repression and devoid of catalase activity. A method was developed for preliminary screening of the transformants with increased FC b 2 activity in permeabilized yeast cells. The optimal cultivation conditions providing for the maximal yield of the target enzyme were found. The constructed strain is a promising FC b 2 producer characterized by a sixfold increased (to 3 μmol min?1 mg?1 protein in cell-free extract) activity of the enzyme. 相似文献
15.
A pure, active cytochrome b
6
f was isolated from the chloroplasts of the marine green alga, Bryopsis
corticulans. To investigate and characterize this cytochrome b
6
f complex, sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), absorption spectra measurement and HPLC were employed. It was shown that this purified complex contained four large subunits with apparent molecular masses of 34.8, 24, 18.7 and 16.7 kD. The ratio of Cyt b
6 to Cytf was 2.01 : 1. The cytochromeb
6
f was shown to catalyze the transfer of 73 electrons from decylplastoquinol to plastocyanin–ferricyanide per Cyt f per second. α-Carotene, one kind of carotenoid that has not been found to present in cytochrome b
6
f complex, was discovered in this preparation by reversed phase HPLC. It was different from β-carotene usually found in cytochrome b
6
f complex. The configuration of the major α-carotene component was assigned to be 9-cis by resonance Raman spectroscopy. Different from the previous reports, the configuration of this α-carotene in dissociated state was determined to be all-trans. Besides this carotene, chlorophyll a was also found in this complex. It was shown that the molecular ratios of chlorophylla, cis and all-trans-α-carotene to Cyt f in this complex were 1.2, 0.7 and 0.2, respectively. 相似文献
16.
We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan. 相似文献
17.
Kum Suk Kang In Deok Kim Ryun Hee Kwon Bae Jin Ha 《Biotechnology and Bioprocess Engineering》2008,13(2):168-173
This study was performed to elucidate the effects of Undaria pinnatifida fucoidan extract (UPFE) in preventing CCl4-induced oxidative stress. UPFE (100 mg/kg) was intraperitoneally administered to rats for 14 days. On day 15, CCl4 dissolved in olive oil (50% CCl4) was injected 12 h before they were anesthetized and dissected. To measure UPFE-mediated antioxidation, we examined the levels
of glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), alkaline phosphatase (ALP), and lactate
dehydrogenase (LDH) in serum, as well as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione
peroxidase (GPx) in liver homogenates. CCl4 treatment markedly increased the levels of GOT, GPT, ALP, LDH, and MDA and significantly decreased levels of SOD, CAT, and
GPx. UPFE pretreatment decreased levels of GOT, GPT, ALP, LDH, and MDA, by 62.8, 68.5, 41.9, 72.7, and 122%, respectively
and increased those of SOD, CAT, and GPx by 111.1, 15.9, and 52.6%, respectively. These results showed that UPFE has antioxidant
effects against CCl4-induced oxidative stress. 相似文献
18.
Summary
Ananas comosus (L.) Merr. var. Smooth Cayenne plants when grown in vitro under different temperature regimes developed as CAM or as C3 plants. The plants used in this study were developed from the lateral buds of the nodal etiolated stem explants cultured
on Murashige and Skoog medium for 3 mo. The cultures were maintained under a 16-h photoperiod for different thermoperiods.
With 28°C light/15°C dark thermoperiod, as compared with constant 28°C light and dark, pineapple plants had a succulence index
two times greater, and also a greater nocturnal titratable acidity and phosphoenolpyruvate carboxylase (PEPCase) activity,
indicating CAM-type photosynthesis. The highest abscisic acid (ABA) level occurred during the light period, 8 h prior to maximum
PEPCase activity, while the indole-3-acetic acid (IAA) peak was found during the dark period, coinciding with the time of
highest PEPCase activity. These plants were also smaller with thicker leaves and fewer roots, but had greater dry weight.
Their leaves showed histological characteristics of CAM plants, such as the presence of greater quantities of chlorenchyma
and hypoderm. In addition, their vascular system was more conspicuous. In contrast, under constant temperature (28°C light/dark)
plants showed little succulence in the leaves. There was no significant acid oscillation and diurnal variation in PEPCase
activity in these plants, suggesting the occurrence of C3 photosynthesis. Also, no diurnal variation in ABA and IAA contents was observed. The results of this study clearly indicate
a role for temperature in determining the type of carbon fixation pathway in in vitro grown pineapple. Evidence that ABA and IAA participate in CAM signaling is provided. 相似文献
19.
Xuesong Zhao Juan Wang Jie Li Ling Fu Juan Gao Xiuli Du Hongtao Bi Yifa Zhou Guihua Tai 《Journal of industrial microbiology & biotechnology》2009,36(5):721-726
Fourteen phytopathogenic fungi were tested for their ability to transform the major ginsenosides to the active minor ginsenoside
Rd. The transformation products were identified by TLC and HPLC, and their structures were assigned by NMR analysis. Cladosporium fulvum, a tomato pathogen, was found to transform major ginsenoside Rb1 to Rd as the sole product. The following optimum conditions for transforming Rd by C. fulvum were determined: the time of substrate addition, 24 h; substrate concentration, 0.25 mg ml−1; temperature, 37°C; pH 5.0; and biotransformation period, 8 days. At these optimum conditions, the maximum yield was 86%
(molar ratio). Further, a preparative scale transformation with C. fulvum was performed at a dose of 100 mg of Rb1 by a yield of 80%. This fungus has potential to be applied on the preparation for Rd in pharmaceutical industry. 相似文献
20.