共查询到20条相似文献,搜索用时 0 毫秒
1.
To develop a gene expression system for Leuconostoc genus, construction of expression vector and expression of a heterologus protein in Leuconostoc was performed. α-Amylase gene from Lactobacillus amylovorus was cloned into a Leuconostoc cloning vector, pLeuCM, with its own signal peptide. pLeuCMamy was introduced into Leuconostoc citreum CB2567 and a successful expression of α-amy gene was confirmed by enzyme activity assays. About 90% of α-amylase activity was detected in the culture broth, revealing
most of expressed α-amylase was secreted out cells. The signal sequence of α-amy gene is a good candidate for the secretion of heterologous protein by using Leuconostoc host-vector system. 相似文献
2.
Twenty Aspergillus strains were evaluated for production of extracellular cellulolytic and xylanolytic activities. Aspergillus brasiliensis, A. niger and A. japonicus produced the highest xylanase activities with the A. brasiliensis and A. niger strains producing thermostable β-xylosidases. The β-xylosidase activities of the A. brasiliensis and A. niger strains had similar temperature and pH optima at 75°C and pH 5 and retained 62% and 99%, respectively, of these activities
over 1 h at 60°C. At 75°C, these values were 38 and 44%, respectively. Whereas A. niger is a well known enzyme producer, this is the first report of xylanase and thermostable β-xylosidase production from the newly
identified, non-ochratoxin-producing species A. brasiliensis. 相似文献
3.
F. -M. Zhu B. Du H. -S. Gao C. -J. Liu J. Li 《Applied Biochemistry and Microbiology》2010,46(6):626-632
Protoplasts of Aspergillus oryzae 3.481 and Aspergillus niger 3.316 were prepared using cellulose and snail enzyme with 0.6 M NaCl as osmotic stabilizer. Protoplast fusion has been performed
using 35% polyethylene glycol 4,000 with 0.01 mM CaCl2. The fused protoplasts have been regenerated on regeneration medium and fusants were selected for further studies. An intracellular
(β-glucosidase (EC 3.2.1.21) was purified from the protoplast fusant of Aspergillus oryzae 3.481 and Aspergillus niger 3.316 and characterized. The enzyme was purified 138.85-fold by ammonium sulphate precipitation, DE-22 ion exchange and Sephadex
G-150 gel filtration chromatography with a specific activity of 297.14 U/mg of protein. The molecular mass of the purified
enzyme was determined to be about 125 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme
had an optimum pH of 5.4 and temperature of 65°C, respectively. This enzyme showed relatively high stability against pH and
temperature and was stable in the pH range of 3.0–6.6. Na+, K+, Ca2+, Mg2+ and EDTA completely inhibited the enzyme activity at a concentration of 10 mM. The enzyme activity was accelerated by Fe3+. The enzyme activity was strongly inhibited by glucose, the end product of glucoside hydrolysis. The K
m and V
max values against salicin as substrate were 0.035 mM and 1.7215 μmol min−1, respectively. 相似文献
4.
Ayla Sant’Ana da Silva Javier Freddy Molina Ricardo Sposina Sobral Teixeira Luis G. Valdivieso Gelves Elba P. S. Bon Viridiana S. Ferreira-Leitão 《Biotechnology letters》2017,39(11):1717-1723
Objective
Glucose conversion into disaccharides was performed with β-glucosidases from Prunus dulcis (β-Pd), Aspergillus niger (β-An) and A. awamori (β-Aa), in reactions containing initial glucose of 700 and 900 g l?1.Results
The reactions’ time courses were followed regarding glucose and product concentrations. In all cases, there was a predominant formation of gentiobiose over cellobiose and also of oligosaccharides with a higher molecular mass. For reactions containing 700 g glucose l?1, the final substrate conversions were 33, 38, and 23.5% for β-An, β-Aa, and β-Pd, respectively. The use of β-An yielded 103 g gentiobiose l?1 (15.5% yield), which is the highest reported for a fungal β-glucosidase. The increase in glucose concentration to 900 g l?1 resulted in a significant increase in disaccharide synthesis by β-Pd, reaching 128 g gentiobiose l?1 (15% yield), while for β-An and β-Aa, there was a shift toward the synthesis of higher oligosaccharides.Conclusion
β-Pd and the fungal β-An and β-Aa β-glucosidases present quite dissimilar kinetics and selective properties regarding the synthesis of disaccharides; while β-Pd showed the highest productivity for gentiobiose synthesis, β-An presented the highest specificity.5.
Petrus J. van Zyl V. Moodley S. H. Rose R. L. Roth W. H. van Zyl 《Journal of industrial microbiology & biotechnology》2009,36(4):611-617
The β-mannanase gene (man1) from Aspergillus aculeatus MRC11624 (Izuka) was patented for application in the coffee industry. For production of the enzyme, the gene was originally
cloned and expressed in Saccharomyces cerevisiae. However the level of production was found to be economically unfeasible. Here we report a 13-fold increase in enzyme production
through the successful expression of β-mannanase of Aspergillus aculeatus MRC11624 in Aspergillus niger under control of the A. niger glyceraldehyde-3-phosphate dehydrogenase promoter (gpd
P) and the A. awamori glucoamylase terminator (glaAT). The effect of medium composition on mannanase production was evaluated, and it was found that the glucose concentration
and the organic nitrogen source had an effect on both the volumetric enzyme activity and the specific enzyme activity. The
highest mannanase activity levels of 16,596 nkat ml−1 and 574 nkat mg−1 dcw were obtained for A. niger D15[man1] when cultivated in a process-viable medium containing corn steep liquor as the organic nitrogen source and high glucose
concentrations. 相似文献
6.
The lipase Lip2 of the edible basidiomycete, Pleurotus sapidus, is an extracellular enzyme capable of hydrolysing xanthophyll esters with high efficiency. The gene encoding Lip2 was expressed
in Escherichia coli TOP10 using the gene III signal sequence to accumulate proteins in the periplasmatic space. The heterologous expression under
control of the araBAD promoter led to the high level production of recombinant protein, mainly as inclusion bodies, but partially
in a soluble and active form. A fusion with a C-terminal His tag was used for purification and immunochemical detection of
the target protein. This is the first example of a heterologous expression and periplasmatic accumulation of a catalytically
active lipase from a basidiomycete fungus. 相似文献
7.
8.
Molecular genetic analysis of melibiose-fermenting Saccharomyces strains isolated from fermentative processes and natural sources in different world regions was conducted to deduce the evolutionary
diversity of Saccharomyces yeasts and find new α-galactosidase MEL genes. The species S. bayanus, S. mikatae, and S. paradoxus were shown to have a single copy of MEL and not accumulate polymeric genes, unlike some S. cerevisiae populations. The polymeric genes MELp1 and MELp2 were identified in S. paradoxus for the first time. Genes identical by 98.7% are located on the chromosomes X and VI, respectively. Phylogenetic analysis
indicates that MEL genes of the Saccharomyces yeasts are species-specific. 相似文献
9.
Hui Ni Huinong Cai Anfeng Xiao Feng Chen Qi You Yaqi Wang 《World journal of microbiology & biotechnology》2011,27(11):2539-2544
To achieve an efficient separation and purification of α-L-rhamnosidase (Rha) from naringinase (Nar) that was prepared from
a fermented broth of Aspergillus niger, improved experimental methods were developed with aid of a chemical dithiothreitol (DTT) and a novel HPLC method. The addition
of DTT did not negatively affect the purification of Rha and Nar, but greatly simplified the purification steps due to its
strong capability of separating the Rha from Nar. The novel HPLC method enabled simultaneous measurement and differentiation
of the Rha and the Nar with the naringin as the substrate. These improvements resulted in an efficient purification of the
homogenous Rha with an estimated molecular weight of 87 kDa. Otherwise, Rha could not be extracted with enough purity even
by the combination of sulphate precipitation, ion exchange chromatography and gel filtration chromatography. The modified
methods have ensured efficient purification of the Rha from A. niger naringinase. This study provides a powerful and simple procedure to separate and purify the Rha of Nar, which will facilitate
further more in-depth studies of these enzymes, as well as their industrial applications. 相似文献
10.
Dana Bernátová 《Biologia》2008,63(2):175-176
The paper brings information on an isolated occurrence and morphological characters of Carex × involuta and C. juncella populations in the Vel’ká Fatra Mts. Their presence has been known neither from the territory of Slovakia nor from the whole
Western Carpathians till now. 相似文献
11.
12.
Archana Kumari Gaurav Sharma Sumangala Bhat Ramesh S. Bhat P. U. Krishnaraj M. S. Kuruvinashetti 《Plant Cell, Tissue and Organ Culture》2011,107(2):215-224
An α-amylase signal peptide from rice was synthesized and fused with endochitinase (ech42) gene cloned from Trichoderma virens. The chimeric gene was designated as PSPα-amyech42, and this was transferred to a plant transformation vector, referred to as pMASGK. Leaf explants of tobacco cv White Burley
were co-cultivated with Agrobacterium tumefaciens strain LBA4404 carrying ech42 with its own signal peptide(ech42SP) and PSPα-amyech42(pMASGK) separately. Putative transformants were selected on Murashige and Skoog (MS) medium, supplemented with 1 mg/l bezyladenine
(BA), 0.5 mg/l naphthalene acetic acid(NAA), and containing 200 mg/l kanamycin and 200 mg/l cefotaxime. Transformation was
further confirmed by PCR with specific primers and Southern blot hybridization. Endochitinase secretion was quantified in
1-week-old cell suspension cultures obtained from 3-week-old callus cultures of transformants carrying PSPα-amyech42, transformants with ech42 and of control (untransformed) plant. Callus cultures of PSPα-amyech42 showed higher endochitinase activity (9–12 times) than those carrying ech42SP (7–8 times) in both medium and cell extracts. Media collected (200 μg of total protein) from PSPα-amyech42 suspension cultures in Potato Dextrose Agar plates showed growth inhibition of 73 and 53% against Sclerotium rolfsii and Rhizoctonia bataticola, respectively, whereas media collected (200 μg of total protein) from ech42SP suspension culture showed inhibition of 14 and 24% against Sclerotium rolfsii and Rhizoctonia bataticola, respectively. 相似文献
13.
Yali Xu Amrita Yasin Thomas Wucherpfennig C. Perry Chou 《World journal of microbiology & biotechnology》2008,24(12):2827-2835
Functional expression of heterologous Pseudozyma antarctica lipase B (PalB) in the periplasm of Escherichia coli was explored using four fusion tags, i.e. DsbC, DsbA, maltose-binding protein (MBP), and FLAG in the sequence of increasing
expression efficacy. Amongst these fusion tags, FLAG and MBP appear to be the most effective ones in terms of boosting enzyme
activity and enhancing solubility of PalB, respectively. Overexpression of these PalB fusions often resulted in concomitant
formation of insoluble inclusion bodies. Coexpression of a selection of periplasmic folding factors, including DegP (and its
mutant variant of DegPS210A), FkpA, DsbA, DsbC, and a cocktail of SurA, FkpA, DsbA, and DsbC, could improve the expression performance. Coexpression
of DsbA appeared to be the most effective in reducing the formation of inclusion bodies for all the four PalB fusions, implying
that functional expression of PalB could be limited by initial bridging of disulfide bonds. Culture performance was optimized
by overexpressing FLAG-PalB with DsbA coexpression, resulting in a high volumetric PalB activity of 360 U/L. 相似文献
14.
Amaro-Reyes A García-Almendárez BE Vázquez-Mandujano DG Amaya-Llano S Castaño-Tostado E Guevara-González RG Loera O Regalado C 《Journal of industrial microbiology & biotechnology》2011,38(9):1311-1319
Xylan constitutes the second most abundant source of renewable organic carbon on earth and is located in the cell walls of
hardwood and softwood plants in the form of hemicellulose. Based on its availability, there is a growing interest in production
of xylanolytic enzymes for industrial applications. β-1,4-xylan xylosidase (EC 3.2.1.37) hydrolyses from the nonreducing end
of xylooligosaccharides arising from endo-1,4-β-xylanase activity. This work reports the partial characterization of a purified
β-xylosidase from the native strain Aspergillus niger GS1 expressed by means of a fungal system. A gene encoding β-xylosidase, xlnD, was successfully cloned from a native A. niger GS1 strain. The recombinant enzyme was expressed in A. niger AB4.1 under control of A. nidulans
gpdA promoter and trpC terminator. β-xylosidase was purified by affinity chromatography, with an apparent molecular weight of 90 kDa, and showed
a maximum activity of 4,280 U mg protein−1 at 70°C, pH 3.6. Half-life was 74 min at 70°C, activation energy was 58.9 kJ mol−1, and at 50°C optimum stability was shown at pH 4.0–5.0. β-xylosidase kept residual activity >83% in the presence of dithiothreitol
(DTT), β-mercaptoethanol, sodium dodecyl sulfate (SDS), ethylenediaminetetraacetate (EDTA), and Zn2+. Production of a hemicellulolytic free xylosidase showed some advantages in applications, such as animal feed, enzymatic
synthesis, and the fruit-juice industry where the presence of certain compounds, high temperatures, and acid media is unavoidable
in the juice-making process. 相似文献
15.
Hubert J Dolecková-Maresová L Hýblová J Kudlíková I Stejskal V Mares M 《Experimental & applied acarology》2005,35(4):281-291
The stored-product mites are the most abundant and frequent group of pests living on the stored food products in Europe. They endanger public health since they produce allergens and transmit mycotoxin-producing fungi. Novel acaricidal compounds with inhibitory effects on the digestive enzymes of arthropods are a safe alternative to the traditional neurotoxic pesticides used for control of the stored-product pests. In this work, we explored the properties of acarbose, the low molecular weight inhibitor of -amylases (AI), as a novel acaricide candidate for protection of the stored products from infestation by Acarus siro (Acari: Acaridae). In vitro analysis revealed that AI blocked efficiently the enzymatic activity of digestive amylases of A. siro, and decreased the physiological capacity of mites gut in utilizing a starch component of grain flour. In vivo experiments showed that AI suppressed the population growth of A. siro. The mites were kept for three weeks on experimental diet enriched by AI in concentration range of 0.005 to 0.25%. Population growth of A. siro was negatively correlated with the content of AI in the treated diet with a half-population dose of 0.125%. The suppressive effect of AIs on stored-product mites is discussed in the context of their potential application in GMO crops 相似文献
16.
From the N-terminal amino acid sequence of the lipase from Aspergillus niger F044, a potential homologous gene A84689 to the lipanl (the gene encoding the lipase from Aspergillus niger F044) was identified. A pair of primers were designed according to the nucleotide sequence of A84689, and the lipanl was cloned by PCR. Nucleotide sequencing revealed that the lipanl has an ORF of 1,044 bp, containing three introns. The deduced amino acid sequence corresponds to 297 amino acid residues.
The cloned cDNA fragment encoding the mature lipase from Aspergillus niger F044 was over-expressed in Escherichia coli BL21(De3) and the recombinant protein was refolded in vitro by dilution followed by DEAE Sepharose Fast Flow chromatography. 相似文献
17.
Suyeon Kim Dae-Seok Lee In Seong Choi Sung-Ju Ahn Yong-Hwan Kim Hyeun-Jong Bae 《Transgenic research》2010,19(3):489-497
Over the past decade various approaches have been used to increase the expression level of recombinant proteins in plants.
One successful approach has been to target proteins to specific subcellular sites/compartments of plant cells, such as the
chloroplast. In the study reported here, hyperthermostable endoglucanase Cel5A was targeted into the chloroplasts of tobacco plants via the N-terminal transit peptide of nuclear-encoded plastid proteins.
The expression levels of Cel5A transgenic lines were then determined using three distinct transit peptides, namely, the light-harvesting
chlorophyll a/b-binding protein (CAB), Rubisco small subunit (RS), and Rubisco activase (RA). RS:Cel5A transgenic lines produced highly stable
active enzymes, and the protein accumulation of these transgenic lines was up to 5.2% of the total soluble protein in the
crude leaf extract, remaining stable throughout the life cycle of the tobacco plant. Transmission election microscopy analysis
showed that efficient targeting of Cel5A protein was under the control of the transit peptide. 相似文献
18.
Transgenic apple (Malus × domestica Borkh.) Florina plants were obtained by Agrobacterium-mediated transformation. The efficiency of gene transfer was 7.9%, calculated as a number of explants producing at least one transgenic shoot, after co-cultivation of leaf explants from in vitro-grown shoots in a thin layer of the A. tumefaciens C58C1 strain with the binary vector pCMB-B:GUS. Polymerase chain reaction revealed that all the clones contained the nptII and rolB genes, while four of them did not contain the gus gene. Southern blot analysis confirmed the integration of the nptII and rolB genes, with one to three copies per genome being present. All independent rolB-transgenic lines were able to produce roots in vitro on the hormone free medium, while the plants, transformed with the vector pIB16.1, or untransformed control plants did not root, and only half of shoots of MM106 rootstock rooted on this medium. The average root number in the rolB-transgenic clones ranged from 4 to 7.7. Pretreatment with indole-3-butyric acid caused root formation in all transgenic and control plants and significantly increased root number in the rolB-transgenic lines, compared to untransformed plants. RolB-transgenic plants, grown in vivo in greenhouse for 2 years, did not differ phenotypically from the wild type line with the exception of root parts. All rolB-transformed plants produced altered root systems containing more fine roots leading to significantly increased fresh root weight in five plant lines. 相似文献
19.
Background
The presence of β-lactamases in Y. enterocolitica has been reported to vary with serovars, biovars and geographical origin of the isolates. An understanding of the β-lactamases in other related species is important for an overall perception of antibiotic resistance in yersiniae. The objective of this work was to study the characteristics of β-lactamases and their genes in strains of Y. intermedia and Y. frederiksenii, isolated from clinical and non-clinical sources in India. 相似文献20.
Two chimeric genes, XynA-Bs-Glu-1 and XynA-Bs-Glu-2, encoding Aspergillus sulphureus β-xylanase (XynA, 26 kDa) and Bacillus subtilis β-1,3-1,4-glucanase (Bs-Glu, 30 kDa), were constructed via in-fusion by different linkers and expressed successfully in Pichia pastoris. The fusion protein (50 kDa) exhibited both β-xylanase and β-1,3-1,4-glucanase activities. Compared with parental enzymes, the moiety activities were decreased in fermentation supernatants. Parental XynA and Bs-Glu were superior to corresponding moieties in each fusion enzymes because of lower Kn higher kcat. Despite some variations, common optima were generally 50°C and pH 3.4 for the XynA moiety and parent, and 40°C and pH 6.4 for the Bs-Glu counterparts. Thus, the fusion enzyme XynA-Bs-Glu-1 and XynA-Bs-Glu-2 were bifunctional. 相似文献