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1.
Xin Li Hui-Ying Yu Yi-Feng Lin Hong-Mei Teng Lei Du Guo-Gang Ma 《Biotechnology letters》2010,32(10):1487-1495
The morphological effects of CF66I, an antifungal compound produced by Burkholderia cepacia, on growing hyphae of Fusarium oxysporum were studied by fluorescence microscopy (FM) and transmission electron microscopy (TEM). At 20 μg/ml, CF66I strongly inhibited
growth and induced significant changes of the hyphal morphology. These changes included swelling of hyphae with considerable
thickening cell wall and abnormal chitin deposition, which was indicative of the alterations in cell wall structure. Furthermore,
fluorescein diacetate (FDA) staining indicated the loss of intracellular esterase activity. CF66I probably inhibits fungal
growth by interfering with the cell metabolic pathways. At 120 μg/ml, CF66I killed F. oxysporum (accompanied by propidium iodide permeation, intracellular cytoplasm leakage and crushing of hyphal tips), probably by direct
damage to the cell membrane. Thus, there are two different antifungal mechanisms of CF66I, depending on its concentration,
and further studies on this compound might be useful for us to develop a new class of antifungal agents. 相似文献
2.
洋葱伯克霍尔德菌CF_66抗菌物质的分离纯化及性质的研究 总被引:15,自引:0,他引:15
洋葱伯克霍尔德菌CF-66能够抑制立枯丝核菌等若干植物病原菌和其它一些真菌的生长。CF-66菌发酵液的粗提液通过Sephadex-75pg、Sephacryl S-100柱层析分离纯化,获得抗菌物质CF66I。此抗菌物质耐热性强,耐碱,但在强酸性条件下不稳定。低浓度有机溶剂的存在有利于抑菌活性的提高。对其结构的研究表明CF66I是以(CH2CH2O)n为主要单元结构并带有酰氨键的化合物。 相似文献
3.
Xin Li Chun-Shan Quan Hui-Ying Yu Jian-Hua Wang Sheng-Di Fan 《World journal of microbiology & biotechnology》2009,25(1):151-154
A novel compound CF66I produced by Burkholeria cepacia was investigated for its antifungal effects against Fusarium solani by three different fluorescent dyes. Dual staining with propidium iodide (PI) and fluorescein diacetate (FDA) demonstrated
high doses of CF66I (120.0 μg ml−1) killed the fungi by acting primarily on the cell membrane. However, at fungistatic concentration (20.0 μg ml−1) of this compound, microscopic observations revealed swelling hyphae with abnormal chitin deposition, as determined by Calcofluor
white (CFW) staining, which was indicative of the alterations in cell wall structure. In addition, inhibition of intracellular
esterases activity was observed. These results led us to conclude that low doses of CF66I probably inhibited the fungal growth
by interfering with the cell metabolic pathways. 相似文献
4.
A novel compound (named CF66I) produced by Burkholeria cepacia CF-66 strain was investigated for its antifungal activity against Candida albicans. This compound exhibited excellent antifungal activity in a dose- and time-dependent manner. Uptake analysis revealed that the compound preferentially acted against the fungal cell wall, and was also able to enter the cells. Transmission electron microscopy indicated that this compound caused loosening of the cell wall and a significant increase in the cell wall thickness was noted; however, no alterations were observed in the contents of the cell wall components. CF66I probably affected the normal assembly and integration of fungal cell wall components by interrupting the weak interactions between them, such as hydrogen and hydrophobic bonds. Propidium iodide (PI) staining indicated that on exposure to CF66I C. albicans cells became permeable to PI. Marked alterations in lipid and sterol contents were observed, and the major changes were a depletion of total lipids and ergosterol, concomitant with an increase in lanosterol content. These observations suggested that the novel compound CF66I may have considerable potential for development of a new class of antifungal agents. 相似文献
5.
Sung-Pin Tseng Wan-Chi Tsai Chih-Yuan Liang Yin-Shiou Lin Jun-Wei Huang Chung-Yu Chang Yu-Chang Tyan Po-Liang Lu 《PloS one》2014,9(8)
Due to the limited information of the contribution of various antibiotic resistance mechanisms in clinical Burkholderia cepacia complex isolates, Antibiotic resistance mechanisms, including integron analysis, identification of quinolone resistance-determining region mutations, measurement of efflux pump activity, and sequence analysis of efflux pump regulators, were investigated in 66 clinical B. cepacia complex isolates. Species were identified via recA-RFLP and MALDI-TOF. Four genomovars were identified by recA-RFLP. B. cenocepacia (genomovar III) was the most prevalent genomovar (90.1%). Most isolates (60/66, 90.9%) were correctly identified by MALDI-TOF analysis. Clonal relatedness determined by PFGE analysis revealed 30 pulsotypes, including two major pulsotypes that comprised 22.7% and 18.2% of the isolates, respectively. Seventeen (25.8%) isolates harboured class 1 integron with various combinations of resistance genes. Among six levofloxacin-resistant isolates, five had single-base substitutions in the gyrA gene and three demonstrated efflux pump activities. Among the 42 isolates exhibiting resistance to at least one antimicrobial agent, 94.4% ceftazidime-resistant isolates (17/18) and 72.7% chloramphenicol-resistant isolates (16/22) demonstrated efflux pump activity. Quantitation of efflux pump RNA level and sequence analysis revealed that over-expression of the RND-3 efflux pump was attributable to specific mutations in the RND-3 efflux pump regulator gene. In conclusion, high-level expression of efflux pumps is prevalent in B. cepacia complex isolates. Mutations in the RND-3 efflux pump regulator gene are the major cause of efflux pump activity, resulting in the resistance to antibiotics in clinical B. cepacia complex isolates. 相似文献
6.
Jacques Balandreau Veronique Viallard Benoit Cournoyer Tom Coenye Severine Laevens Peter Vandamme 《Applied microbiology》2001,67(2):982-985
A polyphasic taxonomic study involving DNA-DNA hybridization, whole-cell protein electrophoresis, and 16S ribosomal DNA sequence analysis revealed that a group of Burkholderia cepacia-like organisms isolated from the rhizosphere or tissues of maize, wheat, and lupine belong to B. cepacia genomovar III, a genomic species associated with “cepacia syndrome” in cystic fibrosis patients. The present study also revealed considerable protein electrophoretic heterogeneity within this species and demonstrated that the B. cepacia complex consists of two independent phylogenetic lineages. 相似文献
7.
Previous studies have identified specific Burkholderia cepacia complex strains that are common to multiple persons with cystic fibrosis (CF). Such so-called epidemic strains have an apparent enhanced capacity for inter-patient spread and reside primarily in Burkholderia cenocepacia (formerly B. cepacia complex genomovar III). We sought to identify strains from B. cepacia complex species other than B. cenocepacia that are similarly shared by multiple CF patients. We performed genotype analysis of 360 recent sputum culture isolates from 360 persons residing in 29 cities by using repetitive extragenic palendromic polymerase chain reaction (rep-PCR) and pulsed field gel electrophoresis. The results indicate that sharing of a common Burkholderia multivorans strain occurs relatively infrequently; however, several small clusters of patients infected with the same strain were identified. A cluster of seven patients infected with the same B. cepacia (genomovar I) strain was found. We also identified a large group of 28 patients receiving care in the same treatment center and infected with the same Burkholderia dolosa strain. These observations suggest that B. cepacia complex strains in species other than B. cenocepacia may be spread among CF patients. 相似文献
8.
O Kilani-Feki I Zouari G Culioli A Ortalo-Magné N Zouari Y Blache S Jaoua 《World journal of microbiology & biotechnology》2012,28(1):275-281
Twenty epiphytic and rhizospheric bacterial strains harbouring strong antifungal activities were isolated from the Tunisian
environment. This group of bacteria was identified as Burkholderia cepacia genomovar I using 16S rDNA and recA fragment gene sequence analyses for two selected strains and RFLP technique for the eighteen other ones. This identification
did not show variability between isolates despite the significant differences in the antifungal activities of their culture
supernatant and the organic crude extract against Aspergillus niger and other phytopathogenic fungi. Chromatographic and mass spectrometric analyses of these extracts allowed us to confirm
the difference between strains of the group. Their metabolic production showed differences in term of contents and quantities
of secreted molecules, particularly those which were identified to be involved in the antifungal activities. Two metabolites,
named Bc-255 and Bc-257 secreted by the entire group at different amounts, have been purified and tested separately against
A. niger. Bc-255 showed an activity twice as high as those shown by Bc-257. The structural characterization of these two compounds
by mass spectrometry and nuclear magnetic resonance spectroscopy allowed their identification as two analogous 2-alkylquinolones
with only one difference at the alkyl chain. 相似文献
9.
Aims: To determine the composition of polar glycopeptidolipids (pGPLs) of Mycobacterium simiae and, particularly, those of ‘habana’ strains, in a search for specific markers given the immunogenic potential of ‘habana’ TMC 5135 in experimental tuberculosis. Methods and Results: pGPLs were determined in free lipid extracts using electrospray ionization‐ion trap‐mass spectrometry (ESI‐IT‐MS), working in both negative‐ and positive‐ion mode. In the case of TMC 5135, the presence of the previously characterized GPL‐II (containing 2,4‐di‐O‐CH3 glucuronic acid as distal sugar in the oligosaccharide antigenic moiety) and GPL‐III (containing 4‐O‐CH3 glucuronic acid as distal sugar) was confirmed using MS/MS and MS/MS/MS approaches. Interestingly, some ‘habana’ strains presented variants of GPL‐II, designated GPL‐II′‐A and GPL‐II′‐B. A di‐O‐CH3‐deoxy‐hexose (tentatively, 2,3‐di‐O‐CH3‐fucose) was identified as the penultimate sugar in the oligosaccharide moiety of GPL‐II′‐A, whereas in GPL‐II′‐B the penultimate sugar was fucose (tentative identification). On the contrary, the distal sugar of the oligosaccharide chain of pGPLs of Myco. simiae ATCC 25275T was identified as tri‐O‐CH3‐glucuronic acid (designated GPL‐simT‐I, with two variants: GPL‐simT‐I‐A and GPL‐simT‐I‐B), O‐CH3‐glucuronic acid (designated GPL‐simT‐II) and di‐O‐CH3‐glucuronic acid (GPL‐II′‐A and GPL‐II′‐B). The penultimate sugar of the oligosaccharide chain of GPL‐simT‐I‐A and GPL‐simT‐II was identified as di‐O‐CH3‐deoxy‐hexose (tentatively, 2,3‐di‐O‐CH3 fucose), and that of GPL‐simT‐I‐B as deoxy‐hexose (tentatively, fucose). In all strains studied, each [M‐H]? and [M+Na]+ ion was revealed as a mixture of homologous compounds varying in the number of –O‐CH3 groups present in the oligosaccharide moiety and in the length of the fatty acyl linked to the peptide. Conclusions: The present work indicates that, within a similar general pattern of pGPLs, different strains of Myco. simiae present some variations, so that new compounds (GPL‐II′‐A, GPL‐II′‐B, GPL‐simT‐I‐A, GPL‐simT‐I‐B and GPL‐simT‐II) were defined. Noteworthy was the fact that the ‘habana’ strains clearly differed from the type strain of Myco. simiae. Significance and Impact of the Study: The data obtained can be used in the delineation of the ‘habana’ group of Myco. simiae, including the quality control of the immunogenic strain ‘habana’ TMC 5135. 相似文献
10.
AIMS: To investigate antifungal activity of a novel compound (named as CF66I provisionally) against plant pathogenic fungi, mainly including Fusarium sp., Colletotrichum lindemuthianum, Rhizoctonia solani, etc. METHODS AND RESULTS: Minimal inhibition concentrations (MIC) and minimal fungicidal concentrations (MFC) of CF66I for each fungi were determined using serial broth dilution method. The data demonstrated MIC ranged from 2.5 to 20.0 microg ml(-1) and MFC were shown at levels of < or =7.5 microg ml(-1) except Fusarium sp. With reverse microscopy, profound morphological alterations of fungal cells were observed after exposure to CF66I. Conidiospores were completely inhibited, and protoplasm aggregated to form chalamydospores because of the changes of cell permeability. Some chalamydospores were broken, suggesting the compound probably possessed strong ability of damaging the cell wall. In addition, CF66I was investigated for its antifungal stability against Curvularia lunata. The results showed CF66I kept strong fungi-static activity over-wide pH range (pH 4-9) and temperature range (from -70 to 120 degrees C). CONCLUSIONS: The compound CF66I exhibited strong and stable broad-spectrum antifungal activity, and had a significant fungicidal effect on fungal cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Results from prebiocontrol evaluations performed to date are probably useful in the search for alternative approaches to controlling serious plant pathogens. 相似文献
11.
Douglas R. Dewey 《American journal of botany》1963,50(10):1028-1034
Dewey, Douglas R. (Utah State U., Logan.) Morphology and (cytology of synthetic hybrids of Agropyron trichophorum X Agropyron cristatum. Amer. Jour. Bot. 50(10): 1028–1034. Illus 1963.—Three hybrids were obtained from controlled crosses of pubescent wheatgrass, A. trichophorum (2n = 42), and hexaploid crested wheatgrass, A. cristatum (211 = 42). The hybrids were intermediate between the parent plants for all vegetative and spike characteristics observed. Under open pollination, 2 of the hybrids set 2 seeds each, and the other hybrid produced 60 seeds. Meiosis in the parent plants was basically regular. Average motaphase-I chromosome associations were 0.09 I, 20.56 II, 0.05 III, and 0.16 IV per cell in the A. trichophorum parent, which was described as a segmental autoallohexaploid. The hexaploid A. cristatum parent averaged 0.18 I, 7.44 II, 0.81 III, 2.86 IV, 0.08 V, and 2.11 VI per cell at diakinesis and was described as an autohexaploid. Chromosome pairing in the hexaploid hybrid averaged 5.08 I, 8.94 II, 4.33 III, 1.11 IV, 0.27 V, and 0.05 VI per cell. On the basis of chromosome pairing in the parent species and their hybrids, it was concluded that 1 of the A. trichophorum genomes was partially homologous with the 3 genomes of hexaploid A. cristatum. Genome formulae for hexaploid A. cristatum, A. trichophorum, and their hybrids were represented as AAAAAA, A1A1B1B1B2B2, and AAAA1B1B2 respectively. 相似文献
12.
Burkholderia cepacia complex: distribution of genomovars among isolates from the maize rhizosphere in Italy 总被引:4,自引:2,他引:2
Fiore A Laevens S Bevivino A Dalmastri C Tabacchioni S Vandamme P Chiarini L 《Environmental microbiology》2001,3(2):137-143
Burkholderia cepacia is a 'complex' in which seven genomic species or genomovars have so far been identified. It appears that all seven B. cepacia genomovars are capable of causing infections in vulnerable persons; in particular, the importance of Burkholderia multivorans (genomovar II) and B. cepacia genomovar III among cystic fibrosis isolates, especially epidemic ones, has been emphasized. In order to acquire a better comprehension of the genomovar composition of environmental populations of B. cepacia, 120 strains were isolated from the rhizosphere of maize plants cultivated in fields located in northern, central and southern Italy. The identification of the different genomovars was accomplished by a combination of molecular polymerase chain reaction (PCR)-based techniques, such as restriction fragment length polymorphism (RFLP) analysis of 16S rDNA (ARDRA), genomovar-specific PCR tests and RFLP analyses based on polymorphisms in the recA gene whole-cell protein electrophoresis. ARDRA analysis allowed us to distinguish between all B. cepacia genomovars except B. cepacia genomovar I, B. cepacia genomovar III and Burkholderia ambifaria (genomovar VII). The latter genomovars were differentiated by means of recA PCR tests and RFLP analyses. Among the rhizospheric isolates of B. cepacia, we found only B. cepacia genomovar I, B. cepacia genomovar III, Burkholderia vietnamiensis (genomovar V) and B. ambifaria. B. cepacia genomovars I and III and B. ambifaria were recovered from all three fields, whereas B. vietnamiensis was detected only in the population isolated from the field located in central Italy. Among strains isolated from northern and southern Italy, the most abundant genomovars were B. ambifaria and B. cepacia genomovar III respectively; in contrast, the population isolated in central Italy showed an even distribution of strains among genomovars. These results indicate that it is not possible to differentiate clinical and environmental strains, or pathogenic and non-pathogenic strains, of the B. cepacia complex simply on the basis of genomovar status, and that the environment may serve as a reservoir for B. cepacia genomovar III infections in vulnerable humans. 相似文献
13.
Ryozo Nakai Sueharu Horinouchi Takeshi Uozumi Teruhiko Beppu 《Bioscience, biotechnology, and biochemistry》2013,77(11):3061-3065
An alkalophilic Streptomyces strain, KSM-9, producing extracellular cellulases was isolated from soil. Three kinds of cellulases that preferentially hydrolyzed carboxymethylcellulose (CMC) were purified from the strain and designated as CMCase I, II and III. The optimum pH of CMCase I (Mr, 32,000) is 8.5 while those of CMCase II (Mr, 32,500) and III (Mr, 92,000) are at around pH 6.0. CMCase I hydrolyzed CMC in a more random fashion than the other two enzymes. 相似文献
14.
Ren Jia Hong Ye Jian Ren Liu Hui Xu Xu Ling Wu Xiao Qin 《World journal of microbiology & biotechnology》2011,27(9):2203-2215
Poplar canker is a kind of serious disease of poplar branches in China and all over the world. In China, the poplar canker
is mainly caused by three pathogens of Cytospora chrysosperma, Phomopsis macrospora and Fusicoccum aesculi, which is hard to control. A collection of 1,013 bacterial isolates obtained from the poplar stems in 9 regions of China.
Of all the strains tested, 13 bacterial isolates inhibiting three pathogens (C. chrysosperma, P. macrospora and F. aesculi) growth were selected, whose inhibition zone width were more than 15 mm. Strain JK-SH007 exhibited the most obvious antagonistic
activity. Besides, this strain also produced extracellular hydrolytic enzymes (β-1, 3-glucanases, proteases and chitinases).
This bacterium had no pathogenicity and was identified as Burkholderia cepacia complex (Bcc) genomovar IX: B. pyrrocinia by the Biolog identification system combined with 16S rDNA and recA gene sequence analysis and morphological, physiological and biochemical methods characteristics. B. pyrrocinia JK-SH007 exhibited the highest biocontrol and colonization capabilities. After 3 months, plant height and ground diameter
in poplar seedlings inoculated with JK-SH007 were significantly (P < 0.05) higher than in control (non-inoculated) plants. The selected B. cepacia isolate colonized poplar stems and leaves endophytically, promoting plant growth and suppressing pathogenic activities of
C. chrysosperma, P. macrospora and F. aesculi on seedling of poplar. This is one of the few reports dealing with isolation and characterization of B. cepacia strains with biocontrol activity against the poplar canker. The endophytic isolate also has the potential to perform as plant
growth promoter. 相似文献
15.
Shi D Guo S Liao S Su R Guo M Liu N Li P Tang Z 《Biological trace element research》2012,145(3):312-317
To investigate the protection of selenium on hepatic mitochondrial functions, 90 7-day-old ducklings were randomly divided
into three groups (groups I–III). Group I was used as a blank control. Group II was administered with aflatoxin B1 (0.1 mg/kg body weight). Group III was administered with aflatoxin B1 (0.1 mg/kg body weight) plus selenium (sodium selenite, 1 mg/kg body weight). All treatments were given once daily for 21 days.
The results showed that the activities of hepatic mitochondrial complexes I–IV in group II ducklings significantly decreased
when compared with group I (P < 0.01). Furthermore, the activities of hepatic mitochondrial complexes I–IV in group III significantly increased when compared
with group II (P < 0.05). The hepatic mitochondrial respiratory control ratio (RCR) in group II ducklings significantly decreased when compared
with group I (P < 0.01). In addition, the hepatic mitochondrial RCR in group III significantly increased when compared with group II (P < 0.05). These results revealed that the aflatoxin B1 significantly induced hepatic mitochondrial dysfunction in the activities of hepatic mitochondrial respiratory chain complexes
I–IV and the RCR in ducklings. However, sodium selenite could significantly ameliorate the negative effect induced by aflatoxin
B1. 相似文献
16.
M. del C. Molina C. A. Naranjo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,73(4):542-550
Summary New cytological evidence supporting x = 5 as the basic chromosome number of the genus Zea has been obtained as a consequence of our analysis of the meiotic configurations of Zea mays ssp. mays, Z. diploperennis, Z. perennis and of four F1 artificial interspecific hybrids. Z. mays ssp. mays (2n = 20) presents regular meiosis with 10 bivalents (II) and is considered here as a typical allotetraploid (A2A2B2B2). In Z. diploperennis (2n = 20) 10II are formed in the majority of the cells, but the formation of 1III + 8II + 1I or 1III + 711 + 3I in 4% of the cells would indicate its segmental allotetraploid nature (A1A1B1B1). Z. perennis (2n = 40) had 5IV + 10II in 55% of the cells and would be considered as an auto-allooctoploid (A1A1A'1A'1C1C1C2C2). Z. diploperennis x Z. mays ssp. mays (2n = 20) presents 10II in ca. 70% of the cells and no multivalents are formed. In the two 2n = 30 hybrids (Z. mays ssp. mays x Z. perennis and Z. diploperennis x Z. perennis) the most frequent meiotic configuration was 5III + 5II + 5I and in 2n = 40 hybrid (Z. diploperennis x Z. perennis) was 5IV + 10II. Moreover, secondary association was observed in the three abovementioned tetraploid taxa (2n = 20) where one to five groups of two bivalents each at diakinesis-metaphase I was formed showing the affinities between homoeologous genomes. The results, as a whole, can be interpreed by assuming a basic x = 5 in this polyploid complex. The main previous contributions that support this working hypothesis are reviewed and its phylogenetic implications studied are discussed. 相似文献
17.
L. S. L'vova I. B. Sedova O. I. Kizlenko V. A. Tutel'yan 《Applied Biochemistry and Microbiology》2003,39(2):197-201
Fusarium moniliforme is the predominant fusarium species in the grain mycoflora of corn grown in the northern Caucasus, accounting for 95% of fusarium isolates. Eighty-five Fusarium moniliforme strains were grown on a grain substrate and checked for the presence of fumonisins (B1 + B2 + B3) by indirect solid-phase enzyme immunoassay. All strains were capable of producing fumonisins (0.95 to 32 500 mg/kg). Strains sampled in Krasnodar krai produced the highest fumonisin levels (averaging 5490 mg/kg). Fusarium moniliforme strains were subdivided into three morphological types. The types differed significantly in the rate of fumonisin production. Strains belonging to the mycelial type (I) produced the greatest amount of the toxin, and those of the pionnotal type (III) were the least active. Strains of the sporodochial type (II) had an intermediate activity. The mean levels of fumonisin accumulation (mg per kg) for each type were I, 7460; II, 1150; and III, 227. 相似文献
18.
The synthesis and electrochemistry of half-sandwich type of Co(III) complexes [(C5Me5)Co(bidentate)(CH3CN)](BF4)2 {bidentate = dppe (1,2-bis(diphenylphosphino)ethane), dppp (1,3-bis(diphenylphosphino)propane), bpy (2,2′-bipyridine), en (ethylenediamine)) are reported. Cyclic voltammograms of [(C5Me5)Co(bidentate)(CH3CN)](BF4)2 in CH3CN s showed two redox couples assignable to Co(II)/Co(III) and Co(I)/Co(II). The Co(I) complex having C5Me5 and dppe was also prepared. Two redox couples of this Co(I) complex, (C5Me5)Co(dppe), in CH3CN coincided with those of [(C5Me5)Co(dppe)(CH3CN)](BF4)2 in spite of the structural change around the metal center. 相似文献
19.
This study aimed at increasing the pyruvate productivity of a multi-vitamin auxotrophic yeast Torulopsis glabrata by redirecting NADH oxidation from adenosine triphosphate (ATP)-production pathway (oxidative phosphorylation pathway) to non-ATP production pathway (fermentative pathway). Two respiratory-deficient mutants, RD-17 and RD-18, were screened and selected after ethidium bromide (EtBr) mutagenesis of the parent strain T. glabrata CCTCC M202019. Compared with the parent strain, cytochrome aa
3 and b in electron transfer chain (ETC) of RD-18 and cytochrome b in RD-17 were disrupted. As a consequence, the activities of key ETC enzymes of the mutant RD-18, including F0F1-ATP synthase, complex I, complex I + III, complex II + III, and complex IV, decreased by 22.2, 41.6, 53.1, 23.6, and 84.7%, respectively. With the deficiency of cytochromes in ETC, a large amount of excessive cytosolic NADH was accumulated, which hampered the further increase of the glycolytic flux. An exogenous electron acceptor, acetaldehyde, was added to the strain RD-18 culture to oxidize the excessive NADH. Compared with the parent strain, the concentration of pyruvate and the glucose consumption rate of strain RD-18 were increased by 26.5 and 17.6%, respectively, upon addition of 2.1 mM of acetaldehyde. The strategy for increasing the glycolytic flux in T. glabrata by redirecting the NADH oxidation pathway may provide an alternative approach to enhance the glycolytic flux in yeast. 相似文献
20.
The catalytic methyl-transfer reaction from methyl tosylate to 1-octanethiol was carried out in the presence of a simple vitamin B12 model complex, [Co(III){(C2C3)(DO)(DOH)pn}Br2], with zinc powder as the reducing reagent at 50 °C. Such a catalytic reaction proceeded via the formation and dissociation of a cobalt-carbon bond in the simple vitamin B12 model complex under non-enzymatic conditions. The mechanism for the methyl-transfer reaction was investigated by electronic and mass spectroscopies. The Co(I) species, which is generated from the reduction of the catalyst by the zinc powder, and its methylated CH3-Co complex were found to be indispensable intermediates. 相似文献