共查询到20条相似文献,搜索用时 31 毫秒
1.
Synthesis, aggregation behavior and in vitro cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid, EPCA) are reported. The synthesis of this unnatural epimer of pythocholic acid (3α,12α,16α-trihydroxy-5β-cholan-24-oic acid, PCA) involves a series of simple and selective chemical transformations with an overall yield of 21% starting from readily available cholic acid (CA). The critical micellar concentration (CMC) of 16-epi-pythocholate in aqueous media was determined using pyrene as a fluorescent probe. In vitro cholesterol solubilization ability was evaluated using anhydrous cholesterol and results were compared with those of other natural di- and trihydroxy bile acids. These studies showed that 16-epi-pythocholic acid (16β-hydroxy-deoxycholic acid) behaves similar to cholic acid (CA) and avicholic acid (3α,7α,16α-trihydroxy-5β-cholan-24-oic acid, ACA) in its aggregation behavior and cholesterol dissolution properties. 相似文献
2.
Svetlana V. Nikiforova Natalia N. Pozdnyakova Olga V. Turkovskaya 《Current microbiology》2009,58(6):554-558
For the first time the production of an emulsifying agent during phthalic, 2,2′-diphenic and α-hydroxy-β-naphthoic acids,
phenanthrene, anthracene, fluorene, pyrene, fluoranthene, and chrysene degradation by white rot fungus Pleurotus ostreatus was found. The emulsifying activity of the cultivation medium after degradation of these compounds was assessed. Maximal
activities were found in the presence of chrysene (48.4%) and α-hydroxy-β-naphthoic acid (52.2%). Emulsifying activity inversely
dependent on the water solubility of the compounds used. Versatile peroxidase was produced concurrently with the emulsifying
agent. 相似文献
3.
A cell line designated as ADG was established from an abalone digestive gland using ERDF medium supplemented with 8% fetal
bovine serum (FBS), 8% abalone hemolymph, and high concentrations of NaCl, KCl, MgCl2, MgSO4, and CaCl2. ADG cells proliferated better in protein-free medium than in FBS-supplemented medium. Among 9 kinds of media examined, ERDF
medium was shown to be optimal for cell growth. ADG cells secreted 13 different kinds of glycosidases in protein-free medium:
α-L-fucosidase, β-L-fucosidase, α-D-galactosidase, β-D-galactosidase, N-acetyl-α-D-galactosaminidase, N-acetyl-β-D-galactosaminidase,
α-D-glucosidase, β-D-glucosidase, N-acetyl-α-D-glucosaminidase, N-acetyl-β-D-glucosaminidase, α-D-mannosidase, β-D-mannosidase,
β-D-xylosidase, and 1-3 xylanase. When ADG cells were cultured in Grace’s insect cell medium, the activity of some secreted
glycosidases increased 25-fold to 65-fold per cell as compared with control cells cultured in ERDF medium. ADG - abalone digestive
gland; ERDF - enriched RDF; FBS - fetal bovine serum; L-15 - Leibovitz’s L-15 media; DME - Dulbecco’s modified Eagle medium;
F-12 - nutrient mixture (Ham); LDF - L-15; DME: F-12 = 10 : 7 : 3; MEM - minimum essential medium; RPMI - RPMI medium 1640;
199 - media 199; GIC - Grace’s insect cell medium; pNP -p -nitrophenol.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
5.
Regio- and Stereo-selective Hydroxylation of Abietic Acid Derivatives by Mucor circinelloides and Mortierella isabellina 总被引:4,自引:0,他引:4
Mucor circinelloides and Mortierella isabellina hydroxylated dehydroabietic acid (DehA). DehA was converted regio- and stereo-selectively by whole cells of Mr. circinelloides to give 2α-hydroxydehydroabietic acid in a 75% molar conversion yield (11 mM from 14.7 mM DehA) after 72 h in the cultivation medium containing 3% (v/v) Tween 80. With cells of Ma. isabellina, under the same conditions, 20.5 mM (6.5 g l−1) 2–hydroxydehydroabietic acid (α/β=81/19) was formed from 26.4 mM DehA. 相似文献
6.
Łukasz Kuźma Zuzanna Skrzypek Halina Wysokińska 《Plant Cell, Tissue and Organ Culture》2006,84(2):100152-100160
Hairy root culture of Salvia sclarea L. was established following infection with Agrobacterium rhizogenes LBA 9402. The culture was grown in growth regulator-free half-strength B5 Gamborg medium with 30 g l−1 sucrose and was investigated with respect to its capability of producing diterpenoids and triterpenoids. Four diterpenoids
(ferruginol, salvipisone, aethiopinone and 1-oxoaethiopinone) and two ursene-type triterpenoids (2α,3α-dihydroxy-urs-12-en-28-oic acid and 2α,3α,24-trihydroxy-urs-12-en-28-oic acid) were isolated from the hairy roots. The presence of three sterols (β-sitosterol, stigmasterol and campesterol), as well as oleanolic and ursolic acids was also shown by GC–MS analysis. The quantitative
and qualitative differences in diterpenoid and triterpenoid production patterns between hairy roots grown in the light and
in the dark were described. 相似文献
7.
Laura Mazzaferro Lucrecia Piñuel Marisol Minig Javier D. Breccia 《Archives of microbiology》2010,192(5):383-393
We screened for microorganisms able to use flavonoids as a carbon source; and one isolate, nominated Stilbella fimetaria SES201, was found to possess a disaccharide-specific hydrolase. It was a cell-bound ectoenzyme that was released to the medium
during conidiogenesis. The enzyme was shown to cleave the flavonoid hesperidin (hesperetin 7-O-α-rhamnopyranosyl-β-glucopyranoside)
into rutinose (α-rhamnopyranosyl-β-glucopyranose) and hesperetin. Since only intracellular traces of monoglycosidase activities
(β-glucosidase, α-rhamnosidase) were produced, the disaccharidase α-rhamnosyl-β-glucosidase was the main system utilized by
the microorganism for hesperidin hydrolysis. The enzyme was a glycoprotein with a molecular weight of 42224 Da and isoelectric
point of 5.7. Even when maximum activity was found at 70°C, it was active at temperatures as low as 5°C, consistent with the
psychrotolerant character of S. fimetaria. Substrate preference studies indicated that the enzyme exhibits high specificity toward 7-O-linked flavonoid β-rutinosides.
It did not act on flavonoid 3-O-β-rutinoside and 7-O-β-neohesperidosides, neither monoglycosylated substrates. In an aqueous
medium, the α-rhamnosyl-β-glucosidase was also able to transfer rutinose to other acceptors besides water, indicating its
potential as biocatalyst for organic synthesis. The monoenzyme strategy of S. fimetaria SES201, as well as the enzyme substrate preference for 7-O-β-flavonoid rutinosides, is unique characteristics among the microbial
flavonoid deglycosylation systems reported. 相似文献
8.
Wang J Zhang Q Huang H Yuan Z Ding D Yang S Jiang W 《Applied microbiology and biotechnology》2007,74(5):1023-1030
Site-directed mutagenesis based on predicted modeled structure of pencillin G acylase from Bacillus megaterium (BmPGA) was followed to increase its performance in the kinetically controlled synthesis of cephalexin with high reactant
concentrations of 133 mM 7-amino-desaceto-xycephalosporanic acid (7-ADCA) and 267 mM d-phenylglycine amide (D-PGA). We directed changes in amino acid residues to positions close to the active site that were expected
to affect the catalytic performance of penicillin acylase: alpha Y144, alpha F145, and beta V24. Alpha F145 was mutated into
tyrosine, alanine, and leucine. Alpha Y144 and beta V24 were mutated into arginine and phenylalanine, respectively. The S/H
ratios of three mutants, BmPGAα144R, BmPGAβ24F, and BmPGAβ24F+α144R, were up to 1.3–3.0 times higher values. Compared to the
wild-type BmPGA, BmPGAβ24F+α144R showed superior potential of the synthetic performance, allowing the accumulation of up to
twofold more cephalexin at significantly higher conversion rates.
Jingang Wang and Qing Zhang contributed equally to this paper. 相似文献
9.
Janice Yang Chou Patricia E. Hugunin Toshiaki Mano 《In vitro cellular & developmental biology. Plant》1983,19(7):571-575
Summary The synthesis of human chorionic gonadotropin (HCG), the subunit of HCG (HCGα), and pregnancy-specific β1-glycoprotein (PSβG) was studied in temperature senstive (ts), simian virus 40 (SV40)tsA mutant-transformed human first trimenster placental (SPA255-26) cells. Retinoic acid increased the production of HCG and PSβG but inhibited the production of HCGα in these cells. Passage
ofSPA255-26 placental cells in medium containing retinoic acid induced a stable altered phenotype characterized by elevated levels of
HCG and PSβG and a reduced level of HCGα. The retinoic acid induced phenotypic changes in these placental cells were reversible;
removal of retinoic acid immediately decreased the production of HCG and PSβG while increasing the production of HCGα. The
ratio of HCG to HCGα in controlSPA255-26 cells was approximately 0.1; this ratio in creased to 4.8 in cells maintained in medium containing retinoic acid. Similarly,
the HCG-to-HCGα ratio increased in choriocarcinoma cells maintained in retinoic acid containing medium. Our data suggest that
retinoic acid may be needed to maintain a blanced production of HCG, HCGα, and PSβG in placental cells in vitro. Retinoic
acid may also play a role in modulating placental protein production during pregnancy. 相似文献
10.
T. V. Malyarenko A. A. Kicha N. V. Ivanchina A. I. Kalinovsky P. S. Dmitrenok A. V. Smirnov 《Russian Journal of Bioorganic Chemistry》2010,36(6):755-761
Thirteen steroidal compounds including three new polyhydroxysteroids, (24R,25S)-24-methyl-5α-cholestane-3β,6α,8,15β,16β,26-hexaol, (22E,24R,25S)-24-methyl-5α-cholest-22-ene-3β,6α,8,15β,16β,26-hexaol, and (22E,24R,25S)-24-methyl-5α-cholest-22-ene-3β,4β,6α,8,15β,16β,26-heptaol, have been isolated along with ten previously known polyhydroxysteroids
from the tropical starfish Asteropsis carinifera collected near the coast of Vietnam. The structures of the new compounds were elucidated by spectroscopic methods (mainly
2D NMR and ESI mass spectrometry). 相似文献
11.
During cultivation in a minimal medium with glucoseAlternaria tenuissima andAspergillus vesicolor produce constitutively α- and β-glucanases. Fractions of β-1,3-glucanases exhibiting affinity for laminarin were separated
by means of gel filtration chromatography. Two neutral β-1,3-glucanases with affinity for yeast glucan were isolated by affinity
chromatography and further characterized. 相似文献
12.
The branched alkanoic acid, 3-methylvaleric acid (3-MVA), was used to test the effect of a β-methyl branch on short chain
alkanoic acid biodegradability by various bacteria. Most of the bacteria tested were able to usen-valeric acid as sole carbon source but were unable to assimilate 3-MVA. Three bacterial strains capable of growth on 3-MVA
are described here because they exemplify metabolism of the branched compound via different strategies.Pseudomonas citronellolis used a β-methyl activation sequence involving CO2 fixation, analogous to that seen in the isovalerate pathway. AMycobacterium sp. used an α-oxidation sequence to convert 3-MVA to 2-methyl-butyrate, which was then assimilated via part of the isoleucine
pathway. AnArthrobacter sp. metabolized 3-MVA via ω-oxidation to produce 3-methylglutarate that was degraded through the 3-hydroxy-3-methylglutarate
pathway. 相似文献
13.
Kemarajt Kemavongse Poonsuk Prasertsan Apichat Upaichit Pawadee Methacanon 《World journal of microbiology & biotechnology》2008,24(10):2073-2085
Medium optimization for production of poly-β-hydroxyalkanoate (PHA) from Rhodobacter sphaeroides U7 cultivated in glutamate–acetate (GA) medium supplemented with 40 mM valeric acid as co-substrate under aerobic-dark condition
was investigated. Studies on effect of nitrogen source and cultivation temperature by conventional and statistical methods
illustrated that (NH4)2SO4 (0.2 g/l) had no effect and the optimal temperature was at 30°C. The optimum environmental conditions were found to be anaerobic-light
(3000 lux) cultivation with aeration rate of 1.0 vvm and agitation speed of 200 rpm for PHA production (2.5 g/l) with the
highest PHA content (65.15%) at 0.5 vvm, and 200 rpm. Under this optimized medium and condition, PHA production from R. sphaeroides U7 increased 3.86-folds (from 0.69 to 2.66 g/l) (PHA content increased 1.5-folds). The biopolymer was purified and characterized
by using 13C NMR, FTIR, DSC, X-ray diffraction and intrinsic viscosity techniques to be a copolymer poly(β-hydroxybutyrate-co-β-hydroxyvalerate)
(PHBV) consisting of 84.8 mol% β-hydroxybutyric acid (HB) and 15.2 mol% β-hydroxyvaleric acid (HV). 相似文献
14.
Molecular characterization based on 16s rDNA gene sequence analysis of bacterial colonies isolated from endosulfan contaminated
soil showed the presence of Ochrobacterum sp, Burkholderia sp, Pseudomonas alcaligenes, Pseudomonas sp and Arthrobacter sp which degraded 57–90% of α-endosulfan and 74–94% of β-endosulfan after 7days. Whole cells of Pseudomonas sp and Pseudomonas alcaligenes showed 94 and 89% uptake of α-isomer and 86 and 89% of β-endosulfan respectively in 120 min. In Pseudomonas sp, endosulfan sulfate was the major metabolite detected during the degradation of α-isomer, with minor amount of endosulfan
diol while in Pseudomonas alcaligenes endosulfan diol was the only product during α-endosulfan degradation. Whole cells of Pseudomonas sp also utilized 83% of endosulfan sulfate in 120 min. In situ applications of the defined consortium consisting of Pseudomonas alcaligenes and Pseudomonas sp (1:1) in plots contaminated with endosulfan showed that 80% of α-endosulfan and 65% of β-endosulfan was degraded after
12 weeks of incubation. Endosulfan sulfate formed during endosulfan degradation was subsequently degraded to unknown metabolites.
ERIC-PCR analysis indicated 80% survival of introduced population of Pseudomonas alcaligenes and Pseudomonas sp in treated plots. 相似文献
15.
16.
Salam A. Ibrahim Awfa Y. Alazzeh Saddam S. Awaisheh Danfeng Song Abolghasem Shahbazi Amer A. AbuGhazaleh 《Biological trace element research》2010,136(1):106-116
The hydrolysis of oligosaccharides and lactose is of great importance to the food industry. Normally, oligosaccharides like
raffinose, stachyose, and verbascose which are rich in different plants like soy bean are considered indigestible by the human
gut. Moreover, many humans suffer from lactose intolerance due to the absence of effective enzyme that can digest lactose.
α-Galactosidase can digest oligosaccharides like raffinose, while β-galactosidases can hydrolyze lactose. Therefore, selection
of microorganisms safe for human use and capable of producing high levels of enzymes becomes an attractive task. The objective
of this study was to investigate the enhancement of α- and β-galactosidase activity in Lactobacillus reuteri by different metal ions. Ten millimolar of Na+, K+, Fe2+, and Mg2+ and 1 mM of Mn2+ were added separately to the growth culture of six strains of L. reuteri (CF2-7F, DSM20016, MF14-C, MM2-3, MM7, and SD2112). Results showed that L. reuteri CF2-7F had the highest α- and β-galactosidase activity when grown in the medium with added Mn2+ ions (22.7 and 19.3 Gal U/ml, respectively). 0.0274% of Mn2+ ions lead to 27, 18% enhancement of α- and β-galactosidase activity over the control group, and therefore, it could be added
to the growth culture of CF2-7F to produce enhanced levels of α- and β-galactosidase activity. The addition of Fe2+ led to a significant (P < 0.01) decrease in the activity of both enzymes for most strains. This study shows that modified culture medium with that
0.0274% Mn2+ can be used to promote the production for α- and β-galactosidase in L. reuteri CF2-7F, which may lead to enhancement of α- and β-galactosidase activity and have a good potential to be used in the food
industry. 相似文献
17.
G. A. D. Haslewood 《The Biochemical journal》1971,123(1):15-18
1. The bile of germ-free domestic fowl contains taurine conjugates of 3α,7α-dihydroxy-5β-cholan-24-oic acid (chenodeoxycholic acid), 3α,7α,12α-trihydroxy-5β-cholan-24-oic acid (cholic acid) and its 5α-epimer (allocholic acid): that of germ-free pigs contains glycine and taurine conjugates of chenodeoxycholic acid, 3α,6α-dihydroxy-5β-cholan-24-oic acid (hyodeoxycholic acid), 3α,6α,7α-trihydroxy-5β-cholan-24-oic acid (hyocholic acid) and (probably) cholic acid. Keto acids were not found. 2. Allocholic acid and hyodeoxycholic acid are thus proved to be primary bile acids in intact animals. 3. The evolutionary and biochemical implications of these findings are briefly considered. 相似文献
18.
A. Trejgell A. Wójciak A. Tretyn 《In vitro cellular & developmental biology. Plant》2002,38(6):564-568
Summary Flower buds and anthers of the short-day plant Pharbitis nil were treated either with thermic shock (7 or 35°C) or osmotic/trophic shock (12% sucrose) for 24 h. Explants were transferred
either to Murashige and Skoog medium (MS) with addition of 6-benzylaminopurine (BA; 4.4μM) and 6% sucrose or to the same growth medium containing 22 μM BA and 3% sucrose. Both media were supplemented with α-naphthaleneacetic acid (NAA; 0.55 μM). Osmotic/trophic shock stimulated the occurrence of shoots on flower buds grown on medium containing 22 μM BA. Thermic shock (7 and 35°C) inhibited this process on both types of explants. Regenerated plantlets were transferred to
MS medium supplemented with 6% sucrose, gibberellic acid (GA3; 1.44μM), NAA (0.55 μM) and Ca2+ (0.66 mgl−1). After 3–4 wk they were able to produce flowers without photoperiodic induction. 相似文献
19.
PA28 subunits of the mouse proteasome: primary structures and chromosomal localization of the genes 总被引:2,自引:0,他引:2
The 20S proteasome is a multi-subunit protease responsible for the production of peptides presented by major histocompatibility
complex (MHC) class I molecules. Recent evidence indicates that an interferon-γ (IFN-γ)-inducible PA28 activator complex enhances
the generation of class I binding peptides by altering the cleavage pattern of the proteasome. In the present study, we determined
the primary structures of the mouse PA28 α- and β-subunits. The deduced amino acid sequences of the α- and β-subunits were
49% identical. We also determined the primary structure of the mouse PA28 γ-subunit (Ki antigen), a protein of unknown function
structurally related to the α- and β-subunits. The amino acid sequence identity of the γ-subunit to the α- and β-subunits
was 40% and 32%, respectively. Interspecific backcross mapping showed that the mouse genes coding for the α- and β-subunits
(designated Psme1 and Psme2, respectively) are tightly linked and map close to the Atp5g1 locus on chromosome 14. Thus, unlike the LMP2 and LMP7 subunits, the IFN-γ-inducible subunits of PA28 are encoded outside
the MHC. The gene coding for the γ-subunit (designated Psme3) was mapped to the vicinity of the Brca1 locus on chromosome 11. A computer search of the DNA databases identified a γ-subunit-like protein in ticks and Caenorhabditis elegans, the organisms with no adaptive immune system. It appears that the IFN-γ-inducible α- and β-subunits emerged by gene duplication
from a γ-subunit-like precursor.
Received: 11 March 1997 相似文献
20.
Strains of fungi imperfecti of generaAspergillus andRhizopus were tested for the ability to produce α-mannosidases. The most suitable α-mannosidase producer of a total of 20 strains
under study wasAspergillus Ravus Link 69. The parameters studied during the cultivation included the growth rate expressed as cell dry weight, α-mannosidase
activity of the extracellular medium withp-nitrophenyl α-D-mannopyranoside as substrate, and utilization ofSaccharomyces cerevisiae mannanvia its disappearance from the cultivation medium. 相似文献