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1.
Wild-type Streptomyces sp. strains, able to utilise both naturally occurring and synthetic organophosphonates, were isolated. High levels of inorganic
phosphate were necessary for their growth in complete medium as well as in medium, supplemented with phosphonates as the sole
carbon or nitrogen source. Isolate StA expressed detectable enzymatic activity against 2-aminoethylphosphonate in vivo. Streptomycete
StC had a surprising ability to degrade N-phosphonomethylglycine (glyphosate) in a phosphate-independent manner via C–P bond cleavage accompanied by sarcosine formation.
Received: 5 January 1999 / Received revision: 8 March 1999 / Accepted: 14 March 1999 相似文献
2.
Andreas Tinschert Andreas Kiener Klaus Heinzmann A. Tschech 《Archives of microbiology》1997,168(5):355-361
2-Hydroxynicotinic acid is an important building block for herbicides and pharmaceuticals. Enrichment strategies to increase
the chances of finding microorganisms capable of hydroxylating at the C2 position and to avoid the degradation of nicotinic
acid via the usual intermediate, 6-hydroxynicotinic acid, were used. Three bacterial strains (Mena 23/3–3c, Mena 25/4–1, and
Mena 25/ 4–3) were isolated from enrichment cultures with 6-methylnicotinic acid as the sole source of carbon and energy.
Partial characterization of these strains indicated that they represent new bacterial species. All three strains completely
degraded 6-methylnicotinic acid, and evidence is presented that the first step in the degradation pathway of strain Mena 23/3–3c
is hydroxylation at the C2 position. Resting cells of this strain grown on 6-methylnicotinic acid also hydroxylated nicotinic
acid at the C2 position, but did not further degrade the product. Strain Mena 23/ 3–3c showed the highest degree of 16S rRNA
sequence similarity to members of the genera Ralstonia and Burkholderia.
Received: 4 April 1997 / Accepted: 10 June 1997 相似文献
3.
Codon Usage Bias and tRNA Abundance in Drosophila 总被引:5,自引:0,他引:5
Codon usage bias of 1,117 Drosophila melanogaster genes, as well as fewer D. pseudoobscura and D. virilis genes, was examined from the perspective of relative abundance of isoaccepting tRNAs and their changes during development.
We found that each amino acid contributes about equally and highly significantly to overall codon usage bias, with the exception
of Asp which had very low contribution to overall bias. Asp was also the only amino acid that did not show a clear preference
for one of its synonymous codons. Synonymous codon usage in Drosophila was consistent with ``optimal' codons deduced from the isoaccepting tRNA availability. Interestingly, amino acids whose
major isoaccepting tRNAs change during development did not show as strong bias as those with developmentally unchanged tRNA
pools. Asp is the only amino acid for which the major isoaccepting tRNAs change between larval and adult stages. We conclude
that synonymous codon usage in Drosophila is well explained by tRNA availability and is probably influenced by developmental changes in relative abundance.
Received: 5 December 1996 / Accepted: 14 June 1997 相似文献
4.
Gui-ming Fu Ru-yi Li Kai-min Li Ming Hu Xiao-qiang Yuan Bin Li 《Preparative biochemistry & biotechnology》2016,46(8):780-787
This study aimed to obtain strains with high glyphosate-degrading ability and improve the ability of glyphosate degradation enzyme by the optimization of fermentation conditions. Spore from Aspergillus oryzae A-F02 was subjected to ultraviolet mutagenesis. Single-factor experiment and response surface methodology were used to optimize glyphosate degradation enzyme production from mutant strain by liquid-state fermentation. Four mutant strains were obtained and named as FUJX 001, FUJX 002, FUJX 003, and FUJX 004, in which FUJX 001 gave the highest total enzyme activity. Starch concentration at 0.56%, GP concentration at 1,370?mg/l, initial pH at 6.8, and temperature at 30°C were the optimum conditions for the improved glyphosate degradation endoenzyme production of A. oryzae FUJX 001. Under these conditions, the experimental endoenzyme activity was 784.15?U/100?ml fermentation liquor. The result (784.15?U/100?ml fermentation liquor) was approximately 14-fold higher than that of the original strain. The result highlights the potential of glyphosate degradation enzyme to degrade glyphosate. 相似文献
5.
6.
A. E. Filonov W. A. Duetz A. V. Karpov R. R. Gaiazov I. A. Kosheleva A. M. Breure I. F. Filonova J. G. van Andel A. M. Boronin 《Applied microbiology and biotechnology》1997,48(4):493-498
Plasmid-carrying Pseudomonas putida strains degrade naphthalene through different biochemical pathways. The influence of various combinations of host bacteria
and plasmids on growth characteristics and competitiveness of P. putida strains was studied in chemostat culture at a low dilution rate (D=0.05 h−1) with naphthalene as the sole source of carbon and energy. Under naphthalene limitation, the plasmid-bearing strains degrading
naphthalene that use catechol 1,2-dioxygenase for catechol oxidation (ortho pathway), were the most competitive. The strains bearing plasmids that control naphthalene catabolism via catechol 2,3-dioxygenase
(meta pathway), were less competitive. Under these conditions the strain carrying plasmid pBS4, which encodes for naphthalene catabolism
via gentisic acid, was the least competitive.
Received: 24 February 1997 / Received revision: 22 May 1997 / Accepted: 25 May 1997 相似文献
7.
G. Giddings L. Mytton M. Griffiths A. McCarthy C. Morgan L. Skøt 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(7):1062-1068
By introducing Bacillus thuringiensis subspecies tenebrionisδ-endotoxin genes (cryIIIA) into Rhizobium leguminosarum we have produced strains for the biological control of Sitona larvae. Comparisons between a transgenic and the parent strain show that transformation has induced changes not associated
with the intended function of the transgene. Although growth rates in laboratory cultures are similar for both strains, the
ability to compete for nodule occupancy is greater in the transgenic than in the non-transformed parent strain. This result
demonstrates the importance of studying ecological and agronomic characters of transgenic micro-organisms that could have
a bearing on the safety and success of their release into the environment, even if they are not thought to be connected with
the transgenes introduced.
Received: 20 April 1997 / Accepted: 2 June 1997 相似文献
8.
M. Megharaj S. Hartmans K.-H. Engesser J. H. Thiele 《Applied microbiology and biotechnology》1998,49(3):337-342
1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) is the peri-chlorinated derivative of 1,1-diphenylethylene (DPE). Biodegradation of DDE and DPE
by bacteria has so far not been shown. Pure cultures of aerobic bacteria involved in biodegradation of styrene and polychlorinated
biphenyls (PCB) were therefore screened for their ability to degrade or cometabolize DPE and DDE. Styrene-metabolizing bacteria
(Rhodococcus strains S5 and VLB150) grew with DPE as their sole source of carbon and energy. Polychlorinated-biphenyl-degrading bacteria
(Pseudomonas fluorescens and Rhodococcus globerulus) were unable to degrade DPE even in the presence of an easily utilizable cosubstrate, biphenyl. This is the first report
of the utilization of DPE as sole carbon and energy source by bacteria. All the tested bacteria failed to degrade DDE when
it was provided as the sole carbon source or in the presence of the respective degradable cosubstrates. DPE transformation
could also be detected in cell-free extracts of Rhodococcus S5 and VLB150, but DDE was not transformed, indicating that cell wall and membrane diffusion barriers were not limiting biodegradation.
The results of the present study show that, at least for some bacteria, the chlorination of DDE is the main reason for its
resistance to biodegradation by styrene and DPE-degrading bacteria.
Received: 28 May 1997 / Received revision: 28 October 1997 / Accepted: 31 October 1997 相似文献
9.
Overexpression of a cytosolic hydroxymethylglutaryl-CoA reductase leads to squalene accumulation in yeast 总被引:4,自引:0,他引:4
The enzyme 3-hydroxy-3-methylglutaryl-coenzyme-A (HMG-CoA) reductase is known as the rate-limiting enzyme in early sterol
biosynthesis in eukaryotic cells. To eliminate this regulation in the yeast Saccharomyces cerevisiae, a truncated HMG1 gene, producing a form of the enzyme that lacks the membrane-binding region (i.e. amino acids 1–552), was constructed and
overexpressed in this yeast. The transformed strains accumulated large amounts of the sterol precursor squalene, while the
levels of ergosterol and a number of other sterol compounds were only slightly elevated. These findings suggest that HMG-CoA
reductase is not the only rate-limiting step in sterol synthesis and its overexpression cannot significantly influence this
pathway beyond the sterol precursor squalene.
Received: 9 June 1997 / Received revision: 1 September 1997 / Accepted: 19 September 1997 相似文献
10.
H. Nishihara Toshiaki Yaguchi Seon Yong Chung Ken-ichiro Suzuki M. Yanagi K. Yamasato T. Kodama Y. Igarashi 《Archives of microbiology》1998,169(4):364-368
Two form ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) genes from the obligately autotrophic, marine hydrogen
oxidizer Hydrogenovibrio marinus were sequenced. The deduced amino acid sequences of both RuBisCOs revealed that they are similar to those of sulfur oxidizers
(Thiobacillus) and a purple sulfur bacterium (Chromatium vinosum). According to the 16S rRNA gene sequences, H. marinus is also affiliated with these microorganisms, members of Thiomicrospira being the closest relatives. Sequence similarities of the 16S rRNA genes and of the RuBisCO genes among these γ-Proteobacteria
suggest a common autotrophic ancestry. An ancestor of purple sulfur bacteria might be a common root of H. marinus and related sulfur oxidizers.
Received: 17 June 1997 / Accepted: 14 November 1997 相似文献
11.
Isolation and characterization of a marine bacterium capable of utilizing 2-methylphenanthrene 总被引:3,自引:0,他引:3
M. Gilewicz Ni'matuzahroh T. Nadalig H. Budzinski P. Doumenq V. Michotey J. C. Bertrand 《Applied microbiology and biotechnology》1997,48(4):528-533
A marine bacterium isolated from a coastal hydrocarbon-polluted sediment has been described and attributed on the basis of
its phenotypic and genotypic characteristics to the genus Sphingomonas sp. This strain was capable of using an alkylated phenanthrene 2-methylphenanthrene, as sole source of carbon and energy.
In experiments, 2-methylphenanthrene (0.2 g/l) was added as crystals to the culture medium. After 5 days of aerobic growth
at 30 °C, 70% was degraded and the complete dissipation occurred after 20 days. Furthermore, the strain could degrade various
kinds of polyaromatic compounds, but failed to grow on aliphatic hydrocarbons.
Received: 27 December 1996 / Received last revision: 10 June 1997 / Accepted: 14 June 1997 相似文献
12.
A series of ts mutations in the GSP1 gene of Saccharomyces cerevisiae was isolated by error-prone PCR. A total of 25 ts gsp1 strains was obtained. Each of these mutants showed between one and seven different amino acid alterations. In several of
these ts gsp1 strains, the same amino acid residues in Gsp1p were repeatedly mutated, indicating that our screen for ts gsp1 mutations was saturating. All of the ts gsp1 strains isolated had a defect in nuclear protein import, but only 16 of the 25 ts gsp1 strains had a defect in mRNA export. Thus, Gsp1p is suggested to be directly involved in nuclear protein import, but not
in mRNA export. Following release from α-factor arrest, 11 of the ts gsp1 mutants arrested in G1; the remainder did not show any specific cell-cycle arrest, at 37° C, the nonpermissive temperature.
While the mutants that are defective in both mRNA export and protein import have a tendency to arrest in G1, there was no
clear correlation between the cell cycle phenotype and the defects in mRNA export and nuclear protein import. Based on this,
we assume that Ran/Gsp1p GTPase regulates the cell cycle and the nucleus/cytosol exchange of macromolecules through interactions
with effectors that were independent of each other, and are differentially affected by mutation.
Received: 30 June 1997 / Accepted: 23 October 1997 相似文献
13.
Y. Pagot A. Le Clainche J.-M. Nicaud Y. Wache J.-M. Belin 《Applied microbiology and biotechnology》1998,49(3):295-300
γ-Decalactone is a peachy aroma compound resulting from the peroxisomal β-oxidation of ricinoleic acid by yeasts. The expression
levels of acyl-CoA oxidase (gene deletion) and 3-ketoacyl-CoA thiolase activities (gene amplification on replicative plasmids)
were modified in the yeast Yarrowia lipolytica. The effects of these modifications on β-oxidation were measured. Overexpression of thiolase activity did not have any effect
on the overall β-oxidation activity. The disruption of one of the acyl-CoA oxidase genes resulted in an enhanced activity.
The enhancement led to an increase of overall β-oxidation activity but reduced the γ-decalactone production rates. This seemed
to indicate a non-rate-limiting role for β-oxidation in the biotransformation of ricinoleic acid to γ-decalactone by the yeast
Yarrowia lipolytica. All strains produced and then consumed γ-decalactone. We checked the ability of the different strains to consume γ-decalactone
in a medium containing the lactone as sole carbon source. The consumption of the strain overexpressing acyl-CoA oxidase activity
was higher than that of the wild-type strain. We␣concluded that peroxisomal β-oxidation is certainly involved in γ-decalactone
catabolism by the yeast Y.␣lipolytica. The observed production rates probably depend on an equilibrium between production and consumption of the lactone.
Received: 13 June 1997 / Received revision: 2 October 1997 / Accepted: 14 October 1997 相似文献
14.
The spiralin genes from two phytopathogenic spiroplasmas, Spiroplasma phoeniceum and Spiroplasma kunkelii, were amplified by PCR, cloned, and sequenced. Comparison of the amino acid sequences of the five spiralins analyzed to date
confirm that the spiralins have a general amphiphilic character and possess a conserved lipoprotein signal peptide. It also
shows that a conserved central region and an amino acid repetition, including a VTKXE consensus sequence, are present in all
spiralins analyzed.
Received: 11 March 1997 / Accepted: 14 April 1997 相似文献
15.
Eighteen fungal strains, known for their ability to degrade lignocellulosic material or lignin derivatives, were screened
for their potential to decolorize commercially used reactive textile dyes. Three azo dyes, Reactive Orange 96, Reactive Violet
5 and Reactive Black 5, and two phthalocyanine dyes, Reactive Blue 15 and Reactive Blue 38, were chosen as representatives
of commercially used reactive dyes. From the 18 tested fungal strains only Bjerkandera adusta, Trametes versicolor and Phanerochaete chrysosporium were able to decolorize all the dyes tested. During degradation of the nickel-phthalocyanine complex, Reactive Blue 38, by B. adusta and T. versicolor respectively, the toxicity of this dye to Vibrio fischeri was significantly reduced. In the case of Reactive Violet 5, a far-reaching detoxification was achieved by treatment with
B. adusta. Reactive Blue 38 and Reactive Violet 5 were decolorized by crude exoenzyme preparations from T. versicolor and B. adusta in a H2O2-dependent reaction. Specific activities of the exoenzyme preparations with the dyes were determined and compared to oxidation
rates by commercial horseradish peroxidase.
Received: 3 February 1997 / Received revision: 9 April 1997 / Accepted: 13 April 1997 相似文献
16.
Naphthalene and phenanthrene have long been used as model compounds to investigate the ability of bacteria to degrade polycyclic
aromatic hydrocarbons. The catabolic pathways have been determined, several of the enzymes have been purified to homogeneity,
and genes have been cloned and sequenced. However, the majority of this work has been performed with fast growing Pseudomonas strains related to the archetypal naphthalene-degrading P. putida strains G7 and NCIB 9816-4. Recently Comamonas testosteroni strains able to degrade naphthalene and phenanthrene have been isolated and shown to possess genes for polycyclic aromatic
hydrocarbon degradation that are different from the canonical genes found in Pseudomonas species. For instance, C. testosteroni GZ39 has genes for naphthalene and phenanthrene degradation which are not only different from those found in Pseudomonas species but are also arranged in a different configuration. C. testosteroni GZ42, on the other hand, has genes for naphthalene and phenanthrene degradation which are arranged almost the same as those
found in Pseudomonas species but show significant divergence in their sequences.
Received 10 August 1997/ Accepted in revised form 15 August 1997 相似文献
17.
Polymorphism of chicken CD8-alpha, but not CD8-beta 总被引:5,自引:0,他引:5
We report here the structural basis of CD8 polymorphism in the chicken. Three chicken strains (RPRL Line 7, H.B15.H7, and H.B15.H12) have 14 nucleotide differences
in the CD8A cDNA sequence causing eight amino acid replacements in the extracellular part of the molecule. Only two amino acid replacements
and four silent mutations were observed in the CD8B cDNA sequence in one (H7) of the strains. Substitutions in CD8α were solely responsible for the binding of CD8-specific monoclonal
antibodies, as detected by cDNA expression in COS cells. The majority of the amino acid substitutions are located in the immunoglobulin
V-like domain and three of the changes (residues 30, 34, and 58) are situated in the putative major histocompatibility complex
class I binding CDR1 and CDR2 regions of the chicken CD8α. CD8A polymorphism has not been reported in other species and this suggests that CD8A and CD8B have evolved under different selective pressures in the chicken.
Received: 28 February 1997 / Revised: 19 April 1997 相似文献
18.
A novel pathway for 2-aminophenol metabolism by Pseudomonas sp. AP-3 is proposed. The proposed pathway is similar to that known for meta-cleavage of catechol except that one of the hydroxyl groups on the metabolites is replaced by an amino group. During the
degradation of 2-aminophenol, 2-amino-2,4-pentadienoic acid is the last metabolite containing an amino group. We, therefore,
propose a modified meta-cleavage pathway for the 2-aminophenol metabolism.
Received: 27 November 1997 / Accepted: 14 May 1998 相似文献
19.
A. Arai S. Masuda A. Matsuyama S. Murakami M. Nakajima 《Applied microbiology and biotechnology》1998,49(3):272-276
The gene for the thermostable pyruvate kinase of Microbispora thermodiastatica IFO 14046, a moderate thermophilic actinomycete, was cloned in Escherichia coli. This gene consists of an open reading frame of 1422 nucleotides and encodes a protein of 474 amino acids with molecular
mass of 50 805 Da. The open reading frame was confirmed as the pyruvate kinase gene by comparison with the N-terminal amino
acid sequence of the purified pyruvate kinase from M. thermodiastatica.
Received: 19 May 1997 / Received last revision: 22 September 1997 / Accepted: 14 October 1997 相似文献
20.
Paecilomyces carneus carboxypeptidase sequentially liberated amino acids from the carboxy-terminus of neurotensin, angiotensin I, bradykinin,
and delta sleep-inducing peptide, indicating that the sequential hydrolysis of peptides was limited by the occurrence of intermediates
with the structure of -Gly-X (X = L-amino acid), -Pro-X, -X-Gly, and -X-Pro. The enzyme had carboxyamidase and/or amidase
activities for the carboxy-terminally amidated peptides. The enzyme essentially acted as a carboxyamidase for the long carboxy-terminally
amidated peptides; an amidase became dominant for the substrates in the presence of bulky amino acids such as Arg, Met, Leu,
and Phe in the penultimate (P1) and P2 positions, corresponding with the S1 and S2 sites of the enzyme, and the P3 position of carboxy-terminally amidated peptides played a significant role in the action as a carboxyamidase or a amidase.
Received: 10 June 1997 / Accepted: 14 July 1997 相似文献