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1.
Cephalosporin production by Streptomyces clavuligerus is known to be negatively regulated by carbon sources, e.g., glycerol and starch, and by phosphate at high concentrations.
Formation of lysine ɛ-aminotransferase (LAT) activity, the first enzyme of the biosynthetic pathway, was affected by a high
concentration of carbon source. Whereas 3% starch more than doubled LAT activity production as compared to 1% starch, 3% glycerol
repressed LAT activity formation by 20%–30%. LAT activity production was not affected by 100 mM K2HPO4. Our results thus show that the negative effects of 2% glycerol and 3% starch and 100 mM phosphate on cephalosporin production
are not due to an effect on production of LAT activity. However, repression of LAT activity by 3% glycerol would be expected
to play a negative role in antibiotic production.
Received: 13 June 1997 / Received revision: 20 August 1997 / Accepted: 25 August 1997 相似文献
2.
Sabine Lutz-Wahl Peter Fischer Claudia Schmidt-Dannert Wolfgang Wohlleben Bernhard Hauer Rolf D. Schmid 《Applied and environmental microbiology》1998,64(10):3878-3881
A total of 215 Streptomyces strains were screened for their capacity to regio- and stereoselectively hydroxylate β- and/or α-ionone to the respective 3-hydroxy derivatives. With β-ionone as the substrate, 15 strains showed little conversion to 4-hydroxy- and none showed conversion to the 3-hydroxy product as desired. Among these 15 Streptomyces strains, S. fradiae Tü 27, S. arenae Tü 495, S. griseus ATCC 13273, S. violaceoniger Tü 38, and S. antibioticus Tü 4 and Tü 46 converted α-ionone to 3-hydroxy-α-ionone with significantly higher hydroxylation activity compared to that of β-ionone. Hydroxylation of racemic α-ionone [(6R)-(−)/(6S)-(+)] resulted in the exclusive formation of only the two enantiomers (3R,6R)- and (3S,6S)-hydroxy-α-ionone. Thus, the enzymatic hydroxylation of α-ionone by the Streptomyces strains tested proceeds with both high regio- and stereoselectivity.Ionones and their derivatives are important intermediates in the metabolism of terpenoids, e.g., in carotenoid biosynthesis, and have been isolated from many sources (1a, 11). Compounds with a trimethylcyclohexane building block constitute essential aroma elements in many plant oils and thus have attracted the attention of the flavor and fragrance industry (3). Further, ionone derivatives, e.g., 3-hydroxy-β-ionone, could prove valuable intermediates for the chemoenzymatic synthesis of carotenoids, e.g., for astaxanthin and zeaxanthin (5).Microbial transformation of α- and/or β-ionone to a number of hydroxy and oxo derivatives has been reported for several fungal strains (2, 4, 8, 9, 18), mainly of the genus Aspergillus, but not for bacterial strains. 3-Hydroxy-α-ionone was observed, among other metabolites, when Cunninghamella blakesleeana ATCC 8688 (2) or Aspergillus niger JTS 191 (18) was used.Many species of the order Actinomycetes are known to catalyze a broad spectrum of xenobiotic transformations. Several cytochrome P-450-dependent monooxygenases from Streptomyces strains, which catalyze the hydroxylation of a wide range of substrates, have been investigated on the molecular level (12) and thus provide an interesting potential as biocatalysts for specific hydroxylation reactions by recombinant techniques.As a first step in this direction, we now report the screening of 215 Streptomyces strains for their capacity to hydroxylate β- and/or α-ionone to the respective 3-hydroxy derivatives in a regio- and stereoselective manner. The structure and stereochemistry of the main biotransformation product were characterized unequivocally by nuclear magnetic resonance (NMR) spectroscopy. 相似文献
3.
Manuel J. López-Nieto Filomena R. Ramos José M. Luengo Juan F. Martín 《Applied microbiology and biotechnology》1985,22(5):343-351
Summary The parameters affecting the formation in vivo of -aminoadipyl-cysteinyl-valine (ACV), an intermediate in penicillin biosynthesis, have been established in low- and high-penicillin producing strains ofPenicillium chrysogenum. ACV was found both in cell extracts and in the culture broth filtrates. (14C)valine, -(14C)aminoadipic acid and (14C)cysteine were efficiently incorporated into ACV. Formation of ACV was stimulated by phenylacetic acid when added during the growth of the culture. ACV biosynthesis was enhanced when protein synthesis was blocked with cycloheximide or anisomicin. The ACV-synthesising activity of the culture increased between 24 and 48 h of the culture preceeding penicillin biosynthesis, and remained constant thereafter. A decay of ACV-forming activity was observed when de novo protein synthesis was inhibited with cycloheximide. The apparent half-life of the ACV-synthesising enzyme system was 2.5 h. 相似文献
4.
David Garciadiego-Cázares Hilda I. Aguirre-Sánchez René F. Abarca-Buis Juan B. Kouri Cristina Velasquillo Clemente Ibarra 《PloS one》2015,10(5)
The Integrin β1 family is the major receptors of the Extracellular matrix (ECM), and the synthesis and degradation balance of ECM is seriously disrupted during Osteoarthritis (OA). In this scenario, integrins modify their pattern expression and regulate chondrocyte differen-tiation in the articular cartilage. Members of the Transforming growth factor beta (Tgf-β) Su-perfamily, such as Growth differentiation factor 5 (Gdf-5) and Bone morphogenetic protein 7 (Bmp-7), play a key role in joint formation and could regulate the integrin expression during chondrocyte differentiation and osteoarthritis progression in an experimental OA rat model. Decrease of α5 integrin expression in articular cartilage was related with chondrocyte dedif-ferentiation during OA progression, while increase of α1, α2, and α3 integrin expression was related with fibrous areas in articular cartilage during OA. Hypertrophic chondrocytes expressedαV integrin and was increased in the articular cartilage of rats with OA. Integrin expression during chondrocyte differentiation was also analyzed in a micromass culture system of mouse embryo mesenchymal cells, micromass cultures was treated with Gdf-5 or Bmp-7 for 4 and 6 days, respectively. Gdf-5 induced the expression of theα5 sub-unit, while Bmp-7 induced the expression of the αV sub-unit. This suggests a switch in signaling for prehypertrophic chondrocyte differentiation towards hypertrophy, where Gdf-5 could maintain the articular chondrocyte phenotype and Bmp-7 would induce hypertrophy. Decrease of Ihh expression during late stages of OA in rat model suggest that the ossification in OA rat knees and endochondral ossification could be activated by Bmp-7 and αV integrin in absence of Ihh. Thus, chondrocyte phenotype in articular cartilage is similar to prehypetrophic chondrocyte in growth plate, and is preserved due to the presence of Indian hedgehog (Ihh), Gdf-5 and α5 integrin to maintain articular cartilage and prevent hy-pertrophy. 相似文献
5.
Kwang Soo Kim Ji-Young Park Ilo Jou Sang Myun Park 《The Journal of biological chemistry》2010,285(28):21416-21425
α-Synuclein is a small presynaptic protein implicated in the pathogenesis of Parkinson disease. Nevertheless, its physiological roles and mechanisms remain incompletely understood. α-Synuclein is not only expressed in neurons but also in the vascular endothelium, which contains intracellular granules called Weibel-Palade bodies (WPBs) that contain a number of chemokines, adhesive molecules, and inflammatory cytokines. This study explored whether the exocytosis of WPB is regulated by α-synuclein. Phorbol 12-myristate 13-acetate-, thrombin-, or forskolin-induced von Willebrand factor release or translocation of P-selectin from endothelial cells were inhibited by α- and β-synuclein but not γ-synuclein. Three point mutants (A30P, A53T, and E46K) found in familial Parkinson disease also inhibited WPB exocytosis similar to that of wild-type α-synuclein. Furthermore, the negative regulation of WPB exocytosis required the N terminus or the nonamyloid β-component of Alzheimer disease amyloid region of α-synuclein, but not the C-terminal acidic tail, and α-synuclein affected WPB exocytosis through interference with RalA activation by enhancing the interaction of RalGDS-β-arrestin complexes. Immuno-EM analysis revealed that α-synuclein was localized close to WPBs. These findings imply that α-synuclein plays as a negative regulator in WPB exocytosis in endothelial cells. 相似文献
6.
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8.
William J Page 《Applied microbiology and biotechnology》1992,38(1):117-121
Summary Vigorously aerated batch cultures of Azotobacter vinelandii UWD formed < 1 g poly--hydroxybutyrate (PHB)/l in media containing pure sugars and 3 g PHB/l in media containing cane molasses, corn syrup or malt extract. However, > 7 g PHB/l was formed when the medium contained 5% beet molasses. Increased yields of PHB were promoted in the media containing pure or unrefined sugars by the addition of complex nitrogen sources. The greatest effect was obtained with 0.05–0.2% fish peptone (FP), proteose peptone no. 3 or yeast extract. Peptones caused a 1.6-fold increase in residual non-PHB biomass and up to a 25-fold increase in PHB content. Hence the increased PHB formation was not simply due to stimulation of culture growth. The amount of PHB per cell protein formed by UWD in media containing FP was greatest in glucose = corn syrup > malt extract > sucrose = fructose = cane molasses > maltose, as carbon sources. The addition of FP to medium containing beet molasses did not stimulate PHB yield. The peptone effect was most significant in well-aerated cultures, which were fixed nitrogen and consuming glucose at a high rate. An explanation for the peptone effect on PHB yield stimulation is proposed. 相似文献
9.
10.
Roberto De Giorgio Maurizio Mazzoni Claudia Vallorani Rocco Latorre Cristiano Bombardi Maria Laura Bacci Monica Forni Mirella Falconi Catia Sternini Paolo Clavenzani 《PloS one》2016,11(2)
BackgroundThe expression of taste receptors (TASRs) and their signalling molecules in the gastrointestinal (GI) epithelial cells, including enteroendocrine cells (EECs), suggests they participate in chemosensing mechanisms influencing GI physiology via the release of endocrine messengers. TASRs mediate gustatory signalling by interacting with different transducers, including α-gustducin (Gαgust) and α-transducin (Gαtran) G protein subunits. This study tested whether Gαtran and Gαgust immunoreactive (-IR) cells are affected by a short-term (3 days) and long-term (30 days) high protein (Hp) diet in the pig GI tract.ResultIn the stomach, Gαgust and Gαtran-IR cells contained serotonin (5-HT) and ghrelin (GHR), while in the small and large intestine, Gαgust and Gαtran-IR colocalized with 5-HT-, cholecystokinin (CCK)- and peptide YY (PYY)-IR. There was a significant increase in the density of Gαtran-IR cells in the pyloric mucosa in both short- and long-term Hp diet groups (Hp3 and Hp30) vs. the control group (Ctr) (P<0.05), while the increase of Gαgust-IR cells in the pyloric mucosa was significant in Hp30 group vs. Ctr and vs. Hp3 (P<0.05); these cells included Gαtran / 5HT-IR and Gαtran / GHR-IR cells (P<0.05 and P<0.001 vs. Ctr, respectively) as well as Gαgust /5-HT-IR or Gαgust / GHR-IR cells (P<0.05 and P<0.01 vs. Ctr, respectively). In the small intestine, we recorded a significant increase in Gαtran-IR cells in the duodenal crypts and a significant increase of Gαgust-IR cells in the jejunal crypts in Hp3 group compared to HP30 (P<0.05). With regard to the number of Gαtran-Gαgust IR cells colocalized with CCK or 5-HT, there was only a significant increase of Gαtran / CCK-IR cells in Hp3 group compared to Ctr (P = 0.01).ConclusionThis study showed an upregulation of selected subpopulations of Gαgust / Gαtran-IR cells in distinct regions of the pig GI tract by short- and long-term Hp diet lending support to TASR-mediated effects in metabolic homeostasis and satiety mechanisms. 相似文献
11.
Hiroshi Sata Hajime Taniguchi Yoshiharu Maruyama 《Bioscience, biotechnology, and biochemistry》2013,77(12):3275-3280
Bacillus circulans F-2 requires a special carbon source or cultural conditions for amylase production. The α-glucosidase production of this bacterium was studied in various cultural conditions with measured glucose concèntrations. High amylase production was always accompanied by low α-glucosidase production and the absence of glucose in culture broth. Usually higher α-glucosidase production was observed in cultural conditions where little amylase was produced. In the presence of 1-deoxynojirimycin, an inhibitor of α-glucosidase activity, the bacterium produced significant amounts of amylase even in conditions giving high α-glucosidase production. It was concluded that the special requirement of this bacterium to produce amylase is effected by its high sensitivity to glucose repression and by the production of α-glucosidase which leads to the formation of glucose. Production of α-glucosidase was, like that of amylase, induced by maltooligosaccharides and repressed by glucose, but both its induction and repression are less sensitive to glucose than those of amylase. 相似文献
12.
Methyl jasmonate (JA-Me) at 10–3
Minhibited Amaranthus caudatus seed germination anddecreased -amylase activity. Exogenous gibberellin A3(GA3) and ethylene, but not benzyladenine (BA), increased activity ofthe enzyme in the presence of JA-Me, with ethylene being the most effective. Theinhibitor of ethylene action, 2,5-norbornadiene (NBD) inhibited seed germinationand decreased -amylase activity. The inhibitory action of JA-Me onAmaranthus caudatus seed germination is associated with theinhibition of -amylase activity. Exogenous GA3 and ethylenecontrol both -amylase activity and seed germination in the presence of JA-Me. 相似文献
13.
《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1988,949(3):288-296
Genes encoding extracellular β-lactamases (EC 3.5.2.6) of Gram-positive Streptomyces badius, Streptomyces cacaoi and Streptomyces fradiae have been cloned into Streptomyces lividans. The β-lactamase gene of S. badius was initially isolated on a 7 kb BamHI fragment and further located on a 1300 bp DNA segment. An 11 kb BamHI fragment was isolated encompassing the S. cacaoi β-lactamase gene, which was subcloned to a 1250 bp DNA fragment. The β-lactamase gene of S. fradiae was cloned on an 8 kb BamHI fragment and mapped to a 4 kb DNA segment. Each of the three BamHI fragments encompassing the β-lactamase genes hybridized to a BamHI fragment of the corresponding size in chromosomal DNA from the respective strain used for cloning. The activities of the three β-lactamases were predominantly found to be extracellular in the S. lividans recombinants. The S. badius and S. cacaoi β-lactamases exhibited a 10–100-times lower activity in S. lividans, whereas the S. fradiae β-lactamase showed an approximately 10-fold higher activity in the cloned state, compared with the activities found in the original strains. 相似文献
14.
The glucoregulatory hormones insulin and glucagon are released from the β- and α-cells of the pancreatic islets. In both cell types, secretion is secondary to firing of action potentials, Ca(2+)-influx via voltage-gated Ca(2+)-channels, elevation of [Ca(2+)](i) and initiation of Ca(2+)-dependent exocytosis. Here we discuss the mechanisms that underlie the reciprocal regulation of insulin and glucagon secretion by changes in plasma glucose, the roles played by different types of voltage-gated Ca(2+)-channel present in α- and β-cells and the modulation of hormone secretion by Ca(2+)-dependent and -independent processes. We also consider how subtle changes in Ca(2+)-signalling may have profound impact on β-cell performance and increase risk of developing type-2 diabetes. 相似文献
15.
α-Amylase was found to be the main protein secreted byBacillus subtilis, corresponding to 90, 87 and 60% of total extracellular proteins at 30, 40 and 45°C, respectively. A change in temperature
can affect the pattern of proteins secreted as detected by gel electrophoresis.14C-Leucine incorporation into extracellular proteins and their proportion at the end of the growth phase was higher at 30°C
than that at 40 or 45°C. The effect of temperature on α-amylase synthesis as determined by its enzymic activity and on the
extracellular protein synthesis followed a similar pattern. 相似文献
16.
Summary Biosynthesis of 1-acetyl--carboline, an enzyme inhibitor, in S. kasugaensis SK-619 was regulated by quality of the carbon source and by addition of organic acids into medium. Variation in phosphate concentration also affected production of this carboline. 相似文献
17.
Summary Glucose and glycerol at concentrations of 2 % negatively affected amylase synthesis in plate and submerged Streptomyces kanamyceticus cultures. This microorganism was insensitive to growth inhibition by glucose analogs and deregulated mutants were identified by a clearing zone around colonies grown on starch and glycerol or glucose, and selected. Three kinds of mutants were obtained: one insensitive to glucose (Mutant 41), another insensitive to glycerol repression (Mutant E) and the last (Mutant 29) an amylase-hyperproducing mutant, albeit regulated by glucose or glycerol like the wild type. The levels of glucokinase, an enzyme involved in catabolite regulation of Enterobacteria, were determined and results showed no differences between the parental strain and the mutants. 相似文献
18.
Ferrochelatase and δ-aminolaevulate synthetase in brain, heart, kidney and liver of normal and porphyric rats. The induction of δ-aminolaevulate synthetase in kidney cytosol and mitochondria by allylisopropylacetamide
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1. delta-Aminolaevulate synthetase was detected in liver and kidney mitochondria prepared from normal rats. 2. The administration of allylisopropylacetamide induced an increase in delta-aminolaevulate synthetase in both liver and kidney mitochondria and the enzyme also appeared in the cytosol fraction of both tissues. Comparison with the distribution of glutamate dehydrogenase indicated that this soluble kidney delta-aminolaevulate synthetase was truly of cytosol origin and did not arise from disrupted mitochondria. The kidney cytosol enzyme was inhibited by 50% by 50mum-protohaem. 3. delta-Aminolaevulate synthetase could not be detected in mitochondria or cytosol from heart or brain from normal or porphyric rats. 4. The administration of allylisopropylacetamide caused little or no increase in ferrochelatase or cytochrome content of liver, kidney, heart or brain mitochondria. 相似文献
19.
J Romero J F Martín P Liras A L Demain N Rius 《Journal of industrial microbiology & biotechnology》1997,18(4):241-246
The L-lysine ɛ-aminotransferase (LAT) of Streptomyces clavuligerus was partially purified and characterized. The 51.3-kDa enzyme exhibited optimal activity at pH 7.0–7.5 and 30°C. It catalyzed
transfer of the terminal amino group of L-lysine or L-ornithine to α -ketoglutarate. Oxalacetate and pyruvate were also used as acceptors of the amino group but with very low efficiency. Increasing
ammonium concentrations added to chemically-defined medium MM enhanced the formation of LAT and decreased production of cephalosporins
by S. clavuligerus. In cultures grown in the absence of lysine, greater enhancement of LAT formation by ammonium and less repression of cephalosporin
biosynthesis were observed. In the chemically-defined GSPG medium, ammonium ions decreased cephalosporin production without
showing an effect on LAT formation.
Received 20 August 1996/ Accepted in revised form 15 November 1996 相似文献
20.
Sang-Min Jung Young-Wook Chin Ye-Gi Lee Jin-Ho Seo 《Biotechnology and bioengineering》2019,116(9):2412-2417
2′-Fucosyllactose (2-FL), one of the most abundant oligosaccharides in human milk, has been spotlighted for its neutraceutical and pharmaceutical potentials. Microbial production of 2-FL is promising since it is efficient as compared to other production methods. In 2-FL microbial production via the salvage pathway for biosynthesis of guanosine 5′-diphosphate (GDP)-l -fucose from fucose, the conversion yield from fucose is important because of the high price of fucose. In this study, deletion of the genes (araA and rhaA) coding for arabinose isomerase (AraA) and rhamnose isomerase (RhaA) was attempted in engineered Escherichia coli for improving 2-FL production by using fucose, lactose, and glycerol. The engineered E. coli constructed previously is able to express fucokinase/GDP-l -fucose pyrophosphorylase (Fkp) from Bacteroides fragilis and the α-1,2-fucosyltransferase (FucT2) from Helicobacter pylori and deficient in β-galactosidase (LacZ), fucose isomerase (FucI), and fuculose kinase (FucK). The additional double-deletion of the araA and rhaA genes in the engineered E. coli enhanced the product yield of 2-FL to 0.52 mole 2-FL/mole fucose, and hence the concentration of 2-FL reached to 47.0 g/L, which are 44% and two-fold higher than those (23.1 g/L and 0.36 mole 2-FL/mole fucose) of the control strain in fed-batch fermentation. Elimination of sugar isomerases exhibiting promiscuous activities with fucose might be critical in the microbial production of 2-FL through the salvage pathway of GDP-l -fucose. 相似文献