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1.
Summary. The paper describes two methods of the synthesis of ethyl (3R,4S)- and (3S,4S)-4-[(benzyloxycarbonyl)amino]-5-[(tert-butyloxycarbonyl)amino]-3-hydroxypentanoates, useful for the syntheses of edeine analogs. Differently N-protected (S)-2,3-diaminopropanoic acid was used as a substrate in both procedures. The absolute configuration of newly generated asymmetric
carbon atoms C-3 in β-hydroxy-γ,δ-diamino products was assigned by means of 1H NMR spectroscopy after their transformation into corresponding piperidin-2-ones.
Received May 24, 2002 Accepted October 10, 2002 Published online December 18, 2002
Acknowledgment The authors are indebted to the Faculty of Chemistry, Technical University of Gdańsk for financial support.
Authors' address: Zbigniew Czajgucki, M. Sc., Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Technical University
of Gdańsk, 11/12 Narutowicza St., 80-952 Gdańsk, Poland, Fax +48 58 347 11 44, E-mail: zmczaj@wp.pl 相似文献
2.
We investigated the relevance of the relationship between the compactness of β-galactosidase inclusion bodies (β-gal IBs)
and their enhanced enzymatic activity with or without the addition of D-fucose (inducer analog) or methyl α-D-glucopyranoside
(α-MG, catabolite repressor) after induction in the araBAD promoter system of Escherichia coli. Experiments conducted to evaluate the solubilization of β-gal IBs in guanidine hydrochloride as well as their trypsin degradation
and temperature stability revealed that β-gal IBs expressed in response to the addition of D-fucose or α-MG had a looser structure.
Additionally, β-gal IBs expressed when D-fucose or α-MG was added were more quickly solubilized in guanidine hydrochloride
or degraded by trypsin-treatment than those produced when these compounds were not added. Moreover, the activity of β-gal
IBs expressed when D-fucose or α-MG were added was less stable at various temperatures. Consequently, we deduced that the
looser structure of β-gal IBs resulted in enhanced enzymatic activity of β-gal IBs upon addition of D-fucose or α-MG after
induction. 相似文献
3.
Esterases are known for their involvement in several physiological processes and high degree of polymorphism, in many organisms.
Such polymorphism has been used to characterize species and species groups and to study genetic changes occurred in their
evolutionary history. In the present study, the esterase patterns of 19 strains from 10 species representative of the five
subgroups of the saltans species group were analyzed using polyacrylamide gel electrophoresis and α- and β- naphthyl acetates as substrates. Fifty-one
esterase bands were detected and classified as 31 α-esterases, 18 β-esterases and two α/β-esterases. On the basis of the inhibition
patterns using Malathion and eserine sulfate, 34 bands were classified as carboxylesterases, 14 as acethylesterases and three
as cholinesterases. Ten gene loci were tentatively established on the basis of data on band position in the gel, substrate
preference and inhibition pattern. Twenty bands were species-specific, the remaining being shared by species from the same
or different subgroups. Bands detected exclusively in males and bands with a different frequency or degree of expression between
sexes were also detected. In the gels prepared for analysis of gene expression in the body parts (head, thorax and abdomen),
the degree of expression of the β-esterases was higher in the thorax, while the α-esterases were expressed predominantly in
the abdomen and thorax. A global view of the data available at present on the esterases of the species from the saltans group and their degree of polymorphism are presented, as well as the possibility of using some β-esterases, because of their
characteristics in the gels, as markers for species identification. 相似文献
4.
5.
Presence and stability of an unusual phycoerythrin (PE) characteristically similar to R-PE are described in a terrestrial,
desiccation-tolerant cyanobacterium, Lyngbya arboricola. Extraction and purification of the PE by using acetone precipitation, gel filtration and ion-exchange chromatography resulted
in achieving a purity index (A560/A280) of up to 5.2. SDS-PAGE of the PE showed presence of 18 kDa, 20 kDa and 32 kDa bands corresponding to α, β and γ subunits
of R-PE without any other contaminating phycobiliproteins (PBPs). The absorption spectrum of the PE was distinguished by two
major peaks at 499 and 559 nm. The maximum fluorescence emission at room temperature was 578 nm. Spectroscopic and electrophoresis
characteristics of PE in the dry mats on storage at 25 ± 1°C over silica gel for 2 years remained almost unaffected. Quantitatively,
storage stability of the PE was in the order of dry mats > lyophilized > liquid state and the impact of temperature on loss
of PE was in the order of 25°C > −20°C > 4°C. The relevance of L. arboricola for production of stable unusual PE is discussed. 相似文献
6.
A putative β-glucosidase gene from the genome of Bacillus halodurans C-125 was expressed in E. coli under the regulation of T7lac promoter. On induction with isopropyl-β-D-1-thiogalactopyranoside, the enzyme expressed at ∼40% of the cell protein producing
238 mg/liter culture. With increase in culture cell density to A
600 12 in auto-inducing M9NG medium, β-glucosidase production increased 3-fold. Approximately 70% of the expressed enzyme was
in a soluble form, while the rest was in an insoluble fraction of the cell lysate. The soluble and active form of the expressed
enzyme was purified by ammonium sulfate precipitation followed by ion-exchange chromatography to a purity >98%. The mass of
the enzyme as determined by MALDI-TOF mass spectrometry was 51,601 Da, which is nearly the same as the calculated value. Phylogenetic
analysis of the β-glucosidase of B. halodurans was found to cluster with members of the genus Bacillus. Temperature and pH optima of the enzyme were found to be 45°C and 8.0, respectively, under the assay conditions. K
m and k
cat against p-nitrophenyl-β-D-glucopyranoside were 4 mM and 0.75 sec−1, respectively. To our knowledge, this is the first report of high-level expression and characterization of a β-glucosidase
from B. halodurans. 相似文献
7.
B. Cukrowska I. Rosiak E. Klewicka I. Motyl M. Schwarzer Z. Libudzisz H. Kozakova 《Folia microbiologica》2010,55(3):277-280
Heat-inactivated Lactobacillus casei LOCK 0900, L. casei LOCK 0908 and Lactobacillus paracasei LOCK 0919 strains, applied to blood cell cultures obtained from children with atopic dermatitis induced production of anti-allergic
TH1 cytokines (interleukin-12, interleukin-18, interferon-γ, tumor necrosis factor-α) and regulatory transforming growth factor-β1), but did not stimulate pro-allergic interleukin-5. The lactobacilli-mixture remarkably enhanced the TH1 response compared to single strains. This synergistic effect was not observed for transforming growth factor-β1. In contrast, the amount of interleukin-10 was found to be considerably lower when cells were stimulated with lactobacilli-mixture
compared to single strains. The mixture of Lactobacillus strains represents a probiotic bacterial preparation modulating in vitro cytokine profile of allergic children towards anti-allergic TH1 response. 相似文献
8.
Joha W. Grobbelaar Z. Wilhelm de Beer Paulette Bloomer Michael J. Wingfield Xu Dong Zhou Brenda D. Wingfield 《Mycoscience》2011,52(2):111-118
Ophiostoma species such as O. quercus are the most frequent causal agents of sapstain of freshly felled hardwood timber and pulpwood. Many species are regarded
as economically important agents of wood degradation. The aim of this study was to identify a collection of Ophiostoma isolates, resembling O. quercus, found on stained Eucalyptus pulpwood chips in China. DNA sequences of the internal transcribed spacer regions, including the 5.8S region, of the ribosomal
DNA, and parts of the β-tubulin and elongation factor-1α genes, revealed that the isolates were not O. quercus. Surprisingly, they represented O. tsotsi, a wound-infesting fungus recently described from hardwoods in Africa. In addition, sequence data from an isolate from agarwood
in Vietnam, identified in a previous study as belonging to an unknown Pesotum species, were also shown to represent O. tsotsi. A high level of genetic variability was observed among isolates of both O. quercus and O. tsotsi. This was unexpected and suggests that both species have been present in Asia for a significant amount of time. 相似文献
9.
Jian-Feng Niu Zhang-Fan Chen Guang-Ce Wang Bai-Cheng Zhou 《Journal of applied phycology》2010,22(1):25-31
R-phycoerythrin was purified by means of phenyl-sepharose expanded bed absorption and DEAE-sepharose ion-exchange chromatography
from Porphyra yezoensis, one of the largest and important aquaculture species in China. Final R-phycoerythrin preparation was characterized by purity
ratio above 4 and the homogeneity in native PAGE, respectively. The results of absorption spectrum, fluorescence spectrum
and SDS-PAGE were in agreement with previous reports on R-PE. The yield of R-phycoerythrin was 0.82 mg g−1 wet leafy gametophyte of P. yezoensis. This method is a high-protein recovery technology while reducing processing time, and is suitable for the large batch production
of R-phycoerythrin, which will enhance the value of P. yezoensis in China, especially the inferior P. yezoensis which can not be used for flake processing. 相似文献
10.
The composition of the essential oil from the wormwood sage (Artemisia frigida Willd., Asteraceae) of populations growing in the Altai Territory, the Altai Republic, the Khakass Republic, the Tuva Republic,
and the East-Kazakhstan region of the Republic of Kazakhstan and the representative species of the silver-leaved wormwood
Artemisia argyrophylla Ledeb. growing in the Republic Altai has been studied by chromato-mass spectrometry. An analysis of 15 samples of the essential
oil from A. frigida obtained over a period from 1999 to 2007 indicates that samples from different populations have similar sets of the main
components: α-pinene (0.2–7.8%), camphene (1.9–5.8%), 1,8-cineole (8.9–33.8%), camphor (6.7–40.0%), borneol (3.9–12.3%), terpine-4-ol
(1.5–6.5%), bornyl acetate (1.4–22.0%), and germacrene D (1.4–14.6%). Some samples contain substantial amounts of α- and β-thujones
(in total up to 19.1%), which are completely absent in other samples. Some samples contain santolina alcohol (up to 13.8%)
and its acetate (up to 4.8%). As differentiated from A. frigida, the essential oil of A. argyrophylla contains yomogi alcohol (1.2%), artemisia ketone (12.9%), artemisia alcohol (3.1%), artemisia alcohol acetate (3.9%), and
small amounts of camphor (3.2%), borneol (0.3%), and bornyl acetate (0.2%). 相似文献
11.
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
12.
Jung Sun Kim Yeon Hee Kim Young Wan Seo Sunghoon Park 《Biotechnology and Bioprocess Engineering》2007,12(3):308-311
Three new acylhomoserine lactone (AHL) inhibitors have been isolated from the Korean red alga.Ahnfeltiopsis flabelliformis, via bioactivity-guided fractionation using the recombinantAgrobacterium tumefaciens liquid culture bioassay. Unlike the majority of AHL inhibitors reported to date, these compounds were α-d-galactopyranosyl-(1→2)-glycerol (floridoside) (1), betonicine (2), and isethionic acid (3), all of which are structurally
unrelated to AHLs. 相似文献
13.
A new phycoerythrin, SCH-phycoerythrin, was purified from Synechococcus sp. ECS-18 by DEAE-Sephacel anion exchange chromatography and Sephacryl S-300 gel filtration. The protein pigment had an
absorbance maximum at 542 nm and a fluorescence maximum at 565 nm. The native molecular mass was approximately 219 kDa as
determined by gel filtration, and sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated the presence of two
subunits, with molecular mass of 19 and 17.9 kDa. These observations are consistent with the (αβ)6 subunit composition that is characteristic of phycoerythrins. The α- and β-subunits showed immunological identity by Ouchterlony
double immunodiffusion with an anti-phycoerythrin antiserum. The DNA sequence of the SCH-phycoerythrin gene was determined
by PCR amplification using primers based on the conserved N-terminal amino acid sequence of the α- and β-subunits of phycoerythrins. 相似文献
14.
V-type Na+-ATPase from Entercoccus hirae consists of nine kinds of subunits (NtpA3, B3, C1, D1, E1−3, F1−3, G1, I1, and K10) which are encoded by the ntp operon. The amino acid sequences of the major subunits, A, B, and K (proteolipid), were highly similar to those of A, B,
and c subunits of eukaryotic V-ATPases, and those of β, α, and c subunits of F-ATPases. We modeled the A and B subunits by
homology modeling using the structure of β and α subunits of F-ATPase, and obtained an atomic structure of NtpK ring by X-ray
crystallography. Here we briefly summarize our current models of the whole structure and mechanism of the E. hirae V-ATPase. 相似文献
15.
16.
Cho HY Seo MJ Park JU Kang BW Kim GY Joo WH Lee YC Cho YS Jeong YK 《Journal of microbiology (Seoul, Korea)》2011,49(6):1018-1021
A fibrinolytic enzyme was found in a Gram-negative bacterium, Aeromonas sp. JH1. SDS-PAGE and fibrinzymography showed that it was a 36 kDa, monomeric protein. Of note, the enzyme was highly specific
for fibrinogen molecules and the hydrolysis rate of fibrinogen subunits was highest for α, β, and γ chains in that order.
The first 15 amino acids of N-terminal sequence were X-D-A-T-G-P-G-G-N-V-X-T-G-K-Y, which was distinguishable from other fibrinolytic
enzymes. The optimum pH and temperature of the enzyme were approximately 8.0 and 40°C, respectively. Therefore, these results
provide a fibrinolytic enzyme with potent thrombolytic activity from the Aeromonas genus. 相似文献
17.
A fungus strain ECU2002, capable of enantioselectively hydrolyzing chiral lactones to optically pure hydroxy acids, was newly
isolated from soil samples through two steps of screening and identified as Fusarium proliferatum (Matsushima) Nirenberg. From the crude extract of F. proliferatum ECU2002, a novel levo-lactonase was purified to homogeneity, with a purification factor of 460-folds and an overall yield of 9.7%, by ultrafiltration,
acetone precipitation, and chromatographic separation through DEAE-Toyopearl, Butyl-Toyopearl, Hydroxyapatite, Toyoscreen-Super
Q, and TSK-gel columns. The purified enzyme is a monomer; with a molecular mass of ca 68 kDa and a pI of 5.7 as determined by two-dimensional electrophoresis. The catalytic performance of the partially purified levo-lactonase was investigated, giving temperature and pH optima at 50°C and 7.5, respectively, for γ-butyrolactone hydrolysis.
The substrate specificity of the partially purified lactonase was also examined using several useful lactones, among which
α-hydroxy-γ-butyrolactone was the best substrate, with 448-fold higher lactonase activity as compared to γ-butyrolactone.
The F. proliferatum lactonase preferentially hydrolyzed the levo enantiomer of butyrolactones, including β-butyrolactone, α-hydroxy-γ-butyrolactone, α-hydroxy-β,β-dimethyl-γ-butyrolactone
(pantolactone), and β-hydroxy-γ-butyrolactone, affording (+)-hydroxy acids in high (94.8∼98.2%) enantiomeric excesses (ee) and good conversions (38.2∼44.2%). A simple immobilization of the crude lactonase with glutaraldehyde cross-linking led
to a stable and easy-to-handle biocatalyst for catalytic resolution of chiral lactones. The immobilized lactonase also performed
quite well in repeated batch resolution of dl-pantolactone at a concentration of 35% (w/v), retaining 67% of initial activity after ten cycles of reaction (corresponding to a half life of 20 cycles) and affording
the product in 94∼97% ee, which can be easily enhanced to >99% ee after the d-hydroxy acid was chemically converted into l-lactone and crystallized. 相似文献
18.
Elena P. Ivanova I. Yu. Bakunina Olga I. Nedashkovskaya Nataliya M. Gorshkova Yulia V. Alexeeva Elena A. Zelepuga T.N. Zvaygintseva Dan V. Nicolau V.V. Mikhailov 《Current microbiology》2003,46(1):0006-0010
The ecophysiological variabilities in the ectohydrolytic enzyme profiles of the three species of Pseudoalteromonas, P. citrea, P. issachenkonii, and P. nigrifaciens, have been investigated. Forty-one bacteria isolated from several invertebrates, macroalgae, sea grass, and the surrounding
water exhibited different patterns of hydrolytic enzyme activities measured as the hydrolysis of either native biopolymers
or fluorogenic substrates. The activities of the following enzymes were assayed: proteinase, tyrosinase, lipase, amylase,
chitinase, agarase, fucoidan hydrolase, laminaranase, alginase, pustulanase, cellulase, β-glucosidase, α- and β-galactosidases,
β-N-acetylglucosaminidase, β-glucosaminidase, β-xylosidase, and α-mannosidase. The occurrence and cell-specific activities
of all enzymes varied over a broad range (from 0 to 44 μmol EU per hour) and depended not only on taxonomic affiliation of
the strain, but also on the source/place of its isolation. This suggests ‘specialization’ of different species for different
types of polymeric substrates as, for example, all strains of P. citrea and P. issachenkonii hydrolyzed alginate and laminaran, while strains of P. nigrifaciens were lacking the ability to hydrolyze most of the algal polysaccharides. The incidence of certain enzymes such as fucoidan
hydrolases, alginate lyases, agarases, and α-galactosidases might be strain specific and reflect its particular ecological
habitat.
Received: 15 February 2002 / Accepted: 27 March 2002 相似文献
19.
C. T. Miyamoto J. Rocha De Sant’anna C. C. Da Silva Franco M. M. Cunico O. G. Miguel L. C. Côcco C. I. Yamamoto C. CorrêaJr M. A. A. De Castro-Prado 《Folia microbiologica》2009,54(6):493-498
Eucalyptus globulus essential oil was evaluated for its genotoxic potential using a somatic segregation assay and a diploid strain of the fungus
Aspergillus nidulans, heterozygous for nutritional and conidia color markers. The main compounds of the current essential oil sample were eucalyptol
(49.0 %), α-pinene (8.9), β-pinene (1.5), globulol (6.9), α-eudesmol (1.12), spathulenol (1.42), γ-cadinene (1.45), trans-β-elemenone (1.23) and aromandendrene (2.3), totaling 74 % of oil. Oil at 0.12 and 0.25 μL/mL was found to increase the mitotic
instability of the original diploid strain and the number of diploid mitotic recombinants of A. nidulans. The genotoxicity of the oil was associated with the induction of mitotic crossing-over or with oil-broken chromosomes. 相似文献
20.
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