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1.
Gopinath V Meiswinkel TM Wendisch VF Nampoothiri KM 《Applied microbiology and biotechnology》2011,92(5):985-996
Corynebacterium glutamicum wild type lacks the ability to utilize the pentose fractions of lignocellulosic hydrolysates, but it is known that recombinants
expressing the araBAD operon and/or the xylA gene from Escherichia coli are able to grow with the pentoses xylose and arabinose as sole carbon sources. Recombinant pentose-utilizing strains derived
from C. glutamicum wild type or from the l-lysine-producing C. glutamicum strain DM1729 utilized arabinose and/or xylose when these were added as pure chemicals to glucose-based minimal medium or
when they were present in acid hydrolysates of rice straw or wheat bran. The recombinants grew to higher biomass concentrations
and produced more l-glutamate and l-lysine, respectively, than the empty vector control strains, which utilized the glucose fraction. Typically, arabinose and
xylose were co-utilized by the recombinant strains along with glucose either when acid rice straw and wheat bran hydrolysates
were used or when blends of pure arabinose, xylose, and glucose were used. With acid hydrolysates growth, amino acid production
and sugar consumption were delayed and slower as compared to media with blends of pure arabinose, xylose, and glucose. The
ethambutol-triggered production of up to 93 ± 4 mM l-glutamate by the wild type-derived pentose-utilizing recombinant and the production of up to 42 ± 2 mM l-lysine by the recombinant pentose-utilizing lysine producer on media containing acid rice straw or wheat bran hydrolysate
as carbon and energy source revealed that acid hydrolysates of agricultural waste materials may provide an alternative feedstock
for large-scale amino acid production. 相似文献
2.
Xu D Pan L Zhao H Zhao M Sun J Liu D 《Journal of industrial microbiology & biotechnology》2011,38(9):1255-1265
Acid protease is essential for degradation of proteins during soy sauce fermentation. To breed more suitable koji molds with
high activity of acid protease, interspecific genome recombination between A. oryzae and A. niger was performed. Through stabilization with d-camphor and haploidization with benomyl, several stable fusants with higher activity of acid protease were obtained, showing
different degrees of improvement in acid protease activity compared with the parental strain A. oryzae. In addition, analyses of mycelial morphology, expression profiles of extracellular proteins, esterase isoenzyme profiles,
and random amplified polymorphic DNA (RAPD) were applied to identify the fusants through their phenotypic and genetic relationships.
Morphology analysis of the mycelial shape of fusants indicated a phenotype intermediate between A. oryzae and A. niger. The profiles of extracellular proteins and esterase isoenzyme electrophoresis showed the occurrence of genome recombination
during or after protoplast fusion. The dendrogram constructed from RAPD data revealed great heterogeneity, and genetic dissimilarity
indices showed there were considerable differences between the fusants and their parental strains. This investigation suggests
that genome recombination is a powerful tool for improvement of food-grade industrial strains. Furthermore, the presented
strain improvement procedure will be applicable for widespread use for other industrial strains. 相似文献
3.
Moo Woong Kim Su-Min Ko Jeong-Yoon Kim Jung-Hoon Sohn Eui-Sung Choi Hyun Ah Kang Sang-Ki Rhee 《Biotechnology and Bioprocess Engineering》2000,5(4):234-241
TheSaccharomyces cerevisiae PMR1 gene encodes a Ca2+-ATPase localized in the Golgi. We have investigated the effects ofPMR1 disruption inS. cerevisiae on the glycosylation and secretion of three heterologous glycoproteins, human α1-antitrypsin (α1-AT), human antithrombin III (ATHIII), andAspergillus niger glucose oxidase (GOD). Thepmr1 null mutant strain secreted larger amounts of ATHIII and GOD proteins per a unit cell mass than the wild type strain. Despite
a lower growth rate of thepmr1 mutant, two-fold higher level of human ATHIII was detected in the culture supernatant from thepmr1 mutant compared to that of the wild-type strain. Thepmr1 mutant strain secreted α1-AT and the GOD proteins mostly as core-glycosylated forms, in contrast to the hyperglycosylated proteins secreted in the
wild-type strain. Furthermore, the core-glycosylated forms secreted in thepmr1 mutant migrated slightly faster on SDS-PAGE than those secreted in themnn9 deletion mutant and the wild type strains. Analysis of the recombinant GOD with anti-α1,3-mannose antibody revealed that
GOD secreted in thepmr1 mutant did not have terminal α1,3-linked mannoses unlike those secreted in themnn9 mutant and the wild type strains. The present results indicate that thepmr1 mutant, with the super-secretion phenotype, is useful as a host system to produce recombinant glycoproteins lacking high-mannose
outer chains. 相似文献
4.
S. Fancelli M. Castaldini M. T. Ceccherini C. Di Serio R. Fani E. Gallori M. Marangolo N. Miclaus M. Bazzicalupo 《Applied microbiology and biotechnology》1998,49(2):221-225
Probes for the detection of Azospirillum strains were obtained from DNA fragments generated by random amplification of polymorphic DNA (RAPD) and tested to assess
their specificity towards DNA extracted from pure cultures. The most specific probe, referred to as α4, produced a hybridization
signal only with amplified DNA of A. lipoferum ATCC29731. This strain was inoculated, together with two other Azospirillum strains, in soil microcosms of different complexity and its presence tested with the probe α4. This probe confirmed its high
specificity with amplified DNA extracted from the soil microcosm and in the presence of other A. lipoferum strains, indicating that the strategy for bacterial detection, based on RAPD markers, is useful for monitoring the presence
of a particular strain under environment-like conditions. Other RAPD-derived probes, when tested on soil samples, did not
show the same level of specificity as that shown on DNA from pure cultures. This result suggests that some precautions are
necessary in the choice of a really specific RAPD marker. In a further development of this strategy, the α4 probe was sequenced
and two pairs of “nested” primers were designed, which enabled a diagnostic polymerase chain reaction from soil samples that
was specific for the A. lipoferum species.
Received: 7 July 1997 / Accepted: 14 October 1997 相似文献
5.
Genome shuffling is a recent development in microbiology. The advantage of this technique is that genetic changes can be made
in a microorganism without knowing its genetic background. Genome shuffling was applied to the marine derived bacterium Nocardia sp. ALAA 2000 to achieve rapid improvement of ayamycin production. The initial mutant population was generated by treatment
with ethyl methane sulfonate (EMS) combined with UV irradiation of the spores, resulting in an improved population (AL/11,
AL/136, AL/213 and AL/277) producing tenfold (150 μg/ml) more ayamycin than the original strain. These mutants were used as
the starting strains for three rounds of genome shuffling and after each round improved strains were screened and selected
based on their ayamycin productivity. The population after three rounds of genome shuffling exhibited an improved ayamycin
yield. Strain F3/22 yielded 285 μg/ml of ayamycin, which was 19-fold higher than that of the initial strain and 1.9-fold higher
than the mutants used as the starting point for genome shuffling. We evaluated the genetic effect of UV + EMS-mutagenesis
and three rounds of genome shuffling on the nucleotide sequence by random amplified polymorphic DNA (RAPD) analysis. Many
differences were noticed in mutant and recombinant strains compared to the wild type strain. These differences in RAPD profiles
confirmed the presence of genetic variations in the Nocardia genome after mutagenesis and genome shuffling. 相似文献
6.
Muhammad Ibrahim Rajoka Muhammad Siddique Awan Mahjabeen Saleem Najma Ayub 《World journal of microbiology & biotechnology》2009,25(2):171-178
The aim of the present investigation was to comparatively evaluate the behaviour of A. niger and its derepressed mutant in production of α-galactosidase in submerged (SmF) and solid state fermentation (SSF) using basal
Vogel’s medium or corn steep liquor as nitrogen source and observe the response of latter source under both cultural techniques
under different temperature regimes, and determine if SSF can be exploited in a wide range of temperature expected to vary
in this fermentation system. All studies were performed in both systems under pre-optimized cultural conditions. Higher melting
temperature and negative values of entropy of activation in SSF indicated that the genetic system of both organisms was thermodynamically
resistant in the presence of corn steep liquor but sensitive to inactivation in the presence of Vogel’s nitrogen sources in
submerged fermentation. This was reflected as the organisms demanded higher magnitudes of energy for product formation in
the presence of ammonium salts. Studies on influence of corn steep liquor revealed that it had stabilizing effect too in both
fermentation systems but the mutant strain was more stable in both fermentation systems. Because of these properties, the
mutant organism may be exploited for bulk production of α-galactosidase in SSF under condition where temperature may fluctuate
during fermentation. 相似文献
7.
Consensus amino acid sequences of FADH2-dependent bacterial halogenases were used to design PCR primers amplifying a halogenase gene fragment from the chloramphenicol
producer Streptomyces venezuelae ISP5230. The sequence-specific degenerate primers (MPF1 and MPR2) were used with a touchdown PCR procedure in the first PCR-assisted
cloning of a halogenase gene fragment. In the region of the 290-bp PCR product containing the reverse primer, the deduced
amino acid sequence exhibited characteristics of a β–α–β fold present in FAD-binding sites of certain monooxygenases. When
used to probe Southern blots of restriction-enzyme-digested DNA, the [α-32P]dCTP-labeled PCR product hybridized specifically with DNA fragments from genomic DNA of S. venezuelae ISP5230. Primers MPF1 and MPR2 also allowed amplification by PCR of approximately 290-bp DNA fragments from several other
streptomycetes. The fragments from Streptomyces aureofaciens NRRL2209 and Streptomyces coelicolor A3(2) showed sequence identity with halogenase genes from these species. Thus, the PCR primers are of potential value for
amplification and subsequent isolation of actinomycete halogenase genes. Journal of Industrial Microbiology & Biotechnology (2002) 29, 1–5 doi:10.1038/sj.jim.7000263
Received 25 June 2001/ Accepted in revised form 02 April 2002 相似文献
8.
Genetic variation among European strains of Saccharomyces paradoxus: results from DNA fingerprinting
We used microsatellite fingerprinting and RAPD analysis to characterize 28 wild European strains of Saccharomyces paradoxus. In contrast to our results from a previous allozyme survey [Naumov et al. Int. J. Syst. Bacteriol. 47: 341-344 (1997a)], these methods revealed extensive genetic variation. The RAPD primers 5'AATCGGGCTG and 5'GGGTAACGCC and the microsatellite primer (GTG)5 yielded reproducible amplification patterns of sufficient clarity and variability to distinguish individual strains from the wild. UPGMA analysis tended to group the strains according to climatic and geographic origin. A comparative study of Ty1 sequence having multiple chromosomal location was also done. Each wild S. paradoxus isolate shows a unique hybridization pattern allowing discrimination to the strain level. 相似文献
9.
Kozoderović G Velhner M Jelesić Z Stojanov I Petrović T Stojanović D Golić N 《Folia microbiologica》2011,56(1):66-71
Molecular typing and resistotyping coupled with gyrA single nucleotide polymorphism (SNP) of 60 Salmonella Enteritidis (SE) isolates originated from poultry, food, and humans in Serbia is described. Molecular fingerprinting was
performed by randomly amplified polymorphic DNA (RAPD) using four primers, and the diversity index (D) was 0.688. In combination with resistotyping and gyrA SNP, D increased to 0.828. A total of 23 genetic groups were obtained. When four RAPD primers were combined, epidemic isolates from
a fast-food restaurant outbreak were clustered in a distinctive genetic group. Among 60 SE strains, three had multiple resistances
to three or more antibiotics. Nine strains were resistant to nalidixic acid (NAL; a non-fluorinated quinolone). The mutations
in quinolone resistance-determining region (QRDR) found in NAL-resistant strains were attributed to Asp87 → Asn in six strains, Asp87 → Gly in one strain, and Ser83 → Phe in one strain. One NAL-resistant strain had no mutations in QRDR, suggesting another mechanism of resistance. 相似文献
10.
Lucia Paciello Elisabetta de Alteriis Cristina Mazzoni Vanessa Palermo Jesus Zueco Palma Parascandola 《Microbial cell factories》2009,8(1):70
Background
Saccharomyces cerevisiae BY4741 is an auxotrophic commonly used strain. In this work it has been used as host for the expression and secretion of human interleukin-1β (IL1β), using the cell wall protein Pir4 as fusion partner. To achieve high cell density and, consequently, high product yield, BY4741 [PIR4-IL1β] was cultured in an aerated fed-batch reactor, using a defined mineral medium supplemented with casamino acids as ACA (auxotrophy-complementing amino acid) source. Also the S. cerevisiae mutant BY4741 Δyca1 [PIR4-IL1β], carrying the deletion of the YCA1 gene coding for a caspase-like protein involved in the apoptotic response, was cultured in aerated fed-batch reactor and compared to the parental strain, to test the effect of this mutation on strain robustness. Viability of the producer strains was examined during the runs and a mathematical model, which took into consideration the viable biomass present in the reactor and the glucose consumption for both growth and maintenance, was developed to describe and explain the time-course evolution of the process for both, the BY4741 parental and the BY4741 Δyca1 mutant strain. 相似文献11.
A number of substrates were tested for the cultivation of microorganisms to produce a host of enzymes. The effect of different
substrates (wheat and rice straw, sugar cane waste, wood waste), incubation temperatures (20–40°C), initial pH levels (3.5–9.0),
incubation periods (0–72 hours) and nitrogen sources (ammonium sulfate, urea, peptone, yeast extract, sodium nitrate) on growth
and α-amylase activity was studied for the native and mutant strains. Maximum enzyme activity was observed at 1.5% wheat straw
for Aspergillus niger FCBP-198 and An-Ch-4.7 and at 2% wheat straw for An-UV-5.6, with sodium nitrate as a principle nitrogen source. The optimum
temperature for maximum enzyme activity was 30°C for the parental strain, while An-UV-5.6 and An-Ch-4.7 thrived well at 32.5°C.
The best conditions of pH and incubation duration were 4.5 and 48 hours, respectively, for all the strains. Mass production
under preoptimized growth conditions demonstrated the suitability of wheat straw for swift mycelial colonization and viability. 相似文献
12.
A rifampin-resistant mutant ofCellulomonas biazotea secreted elevated levels of cellulasesin vivo. The cellulase production in the mutant was not inhibited in the presence of 5% glucose, cellobiose or glycerol in the solid
medium. The mutant exhibited approximately two- to three-fold enhanced product yields and productivity of cellular β-glucosidase
over the wild parent in shake-flask culture studies when grown on either cellulosic or lignocellulosic substrates. Extracellular
production of filter paper cellulase (FPase) and endo-glucanase (CMCase) were also significantly (p≤0.05) altered. During growth of the mutant on α-cellulose, the maximum volumetric productivities for CMCase, FPase and β-glucosidase
were 52, 23.3, and 15.2 IUL−1 h−1,i.e 118, 121, and 229% their respective values for the parental strain. Some enzyme properties of the mutant cellulases were
altered. Mutant-derived cellulases produced higher yields of glucose arising by degradation of bagasse, wheat straw, and α-cellulose
(1.53-, 1.57-, and 1.75-fold, respectively). 相似文献
13.
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
14.
M. I. Rajoka Tayyaba Huma A. M. Khalid F. Latif 《World journal of microbiology & biotechnology》2005,21(6-7):869-876
Summary Industrial byproducts namely canola meal, rice bran, sunflower meal, and wheat straw were used as substrates for endo-xylanase
production by Humicola lanuginosemutant TH1 through solid substrate fermentation. The enzyme was secreted extracellularly by both wild and mutant cultures.
Rice bran supported the maximum production of endo-xylanase followed by wheat straw, canola meal and sunflower meal. The highest
activity was achieved after 72 h of culture and the highest yields from the above substrates were 842, 840, 610 and 608 IU
per g substrate consumed respectively. The highest productivity (281 IU flask−1 h−1 corresponding to 5620 l−1 h-1) of endo-xylanase by the mutant of H. lanuginosa was 1.6-fold more than that produced by the parental organism in solid-state fermentation of rice bran at 45 °C. Maximum
specific activity (180 IU mg−1 protein) and substrate consumption rates were significantly more than those reported by previous researchers on Humicola sp. The mutant possessed markedly low accompanying cellulase activity. Thermodynamic studies revealed that the mutant required
significantly lower activation energy for enzyme production and higher for thermal inactivation which signified that the endogenous
metabolic machinery of mutant cells exerted more protection against thermal inactivation during product formation than that
needed by its parental cultures. 相似文献
15.
S. Parvez M. I. Rajoka M. N. Ahmed F. Latif R. Shahid K. A. Malik 《Folia microbiologica》1998,43(1):59-62
Citric acid production from sugar cane molasses byAspergillus niger NIAB 280 was studied in a batch cultivation process. A maximum of 90 g/L total sugar was utilized in citric acid production
medium. From the parental strainA. niger, mutant strains showing resistance to 2-deoxyglucose in Vogal's medium containing molasses as a carbon source were induced
by γ-irradiation. Among the new series of mutant strains, strain RP7 produced 120 g/L while the parental strain produced 80
g/L citric acid (1.5-fold improvement) from 150 g/L of molasses sugars. The period of citric acid production was shortened
from 10 d for the wild-type strain to 6–7 d for the mutant strain. The efficiency of substrate uptake rate with respect to
total volume substrate consumption rate,Q
s (g per L per h) and specific substrate consumption rate,q
s (g substrate per g cells per h) revealed that the mutant grew faster than its parent. This indicated that the selected mutant
is insensitive to catabolite repression by higher concentrations of sugars for citric acid production. With respect to the
product yield coefficient (Y
p/x), volume productivity (Q
p) and specific product yields (q
p), the mutant strain is significantly (p≤0.05) improved over the parental strain. 相似文献
16.
Przetakiewicz J Nadolska-Orczyk A Kuć D Orczyk W 《Cellular & molecular biology letters》2007,12(2):253-267
Intraspecific somatic hybrids between 16 different diploid breeding lines of Solanum tuberosum L. were produced by PEG-induced fusion. Manually selected heterokaryons were cultured in a Millicells-CM using a post-fusion
protoplast mixture. Plants were regenerated from calli derived from heterokaryons obtained from 10 out of 38 combinations
of diploid lines. Of the tested putative somatic hybrids, 14.2% were diploid, 72.8% were tetraploid and 13% pentaploid. The
DNA amplification pattern obtained with RAPD or semi-random primers confirmed that 6 fusion combinations were hybrids. In
most cases, the morphological traits were intermediate to those of the diploid fusion partners. About 23.0% of the tested
somatic hybrids showed variation in their morphology. Of the tested somatic hybrids, 78.0% flowered and 86.0% tuberized. The
cytoplasm of 9 diploid lines and 6 somatic hybrid combinations was analysed. Two of the diploid lines had W/S chloroplasts
and α or ε mitochondria; the remainder contained T chloroplasts and β mitochondria. All the analysed somatic hybrids carried
T chloroplasts and β mitochondria. 相似文献
17.
H. S. Suh Y. I. Sato H. Morishima 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):316-321
Weedy rice (Oryza sativa L.) is an important resource for breeding and for studying the evolution of rice. The present study was carried out to identify
the genetic basis of the weedy rices distributed in various countries of the world. One hundred and fifty two strains of weedy
rice collected from Bangladesh, Brazil, Bhutan, China, India, Japan, Korea, Nepal, Thailand and the USA were tested for variations
in six morpho-physiological characteristics and in 14 isozyme loci. Twenty six weedy strains selected from the above materials
were assayed for the Est-10 locus, six RAPD loci of the nuclear genome, and one chloroplast locus. From the results of multivariate analysis based on
the morpho-physiological characteristics and the isozymes, weedy rice strains were classified into indica and japonica types, and each type was further divided into forms resembling cultivated and wild rice. Thus, four groups designated as
I, II, III and IV were identified. Weedy strains of group I (indica-type similar to cultivars) were distributed mostly in temperate countries, group II (indica-type similar to wild rice) in tropical countries, group III (japonica-type similar to cultivars) in Bhutan and Korea, group IV ( japonica-type similar to wild rice) in China and Korea. In group I, classified as indica, several strains showed japonica-specific RAPD markers, while some others had japonica cytoplasm with indica-specific RAPD markers in a heterozygous state at several loci. One weedy strain belonging to group II showed a wild rice-specific
allele at the Est-10 locus. However, in groups III and IV, no variation was ound either for the markers on Est-10 or for the RAPD loci tested. Judging from this study, weedy rice of group I might have originated at least partly from gene
flow between indica and japonica, whereas that of group II most probably originated from gene flow between wild and cultivated indica rice. Weedy rice of group III is thought to have originated from old rice cultivars which had reverted to a weedy form, and
that of group IV from gene flow between japonica cultivars and wild rice having japonica backgrounds.
Received: 2 May 1996 / Accepted: 30 August 1996 相似文献
18.
19.
Zhi-Hua Feng Yuan-Shan Wang Yu-Guo Zheng 《Biotechnology and Bioprocess Engineering》2011,16(5):894-900
Alpha-amylase inhibitors are widely used by the pharmaceutical and agricultural industries, such as the treatment of diabetes
and obesity and insect controller. Here, we developed a colorimetric method to screen for α-amylase inhibitor producing strains or mutants with higher α-amylase inhibitor productivity. This method relies on absorbance changes at 402 nm that are due to the inhibition of α-amylase catalyzed hydrolysis of 2-Chloro-4-nitrophenyl-4-O-β-D-galactopyranosyl-maltoside by α-amylase inhibitors. The assay can be performed on a microtiter plate, making it simple and convenient. Using this method,
α-amylase inhibitor producing strains and mutants with higher α-amylase inhibitor productivity can be rapidly screened. One strain, ZJB-08196, with the highest α-amylase inhibition was isolated and identified as Actinoplanes utahensis, and one mutant with higher acarbose production was obtained by screening 3,000 variants using this method. 相似文献
20.
vanKuyk PA Benen JA Wösten HA Visser J de Vries RP 《Applied microbiology and biotechnology》2012,93(1):285-293
AmyR is commonly considered a regulator of starch degradation whose activity is induced by the presence of maltose, the disaccharide
building block of starch. In this study, we demonstrate that the role of AmyR extends beyond starch degradation. Enzyme activity
assays, genes expression analysis and growth profiling on d-glucose- and d-galactose-containing oligo- and polysaccharides showed that AmyR regulates the expression of some of the Aspergillus niger genes encoding α- and β-glucosidases, α- and β- galactosidases, as well as genes encoding α-amlyases and glucoamylases. In
addition, we provide evidence that d-glucose or a metabolic product thereof may be the inducer of the AmyR system in A. niger and not maltose, as is commonly assumed. 相似文献