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N. Sriubolmas W. Panbangred S. Sriurairatana V. Meevootisom 《Applied microbiology and biotechnology》1997,47(4):373-378
Various concentrations of isopropyl β-d-thiogalactopyranoside (IPTG) were used to induce production of the enzyme penicillin G acylase by recom binant Escherichia coli harboring plasmid pQEA11. The plasmid pQEA11 carries a wild-type pga gene, which is under the control of the tac promoter and lacI q. At low IPTG concentrations (0.025 – 0.1 mM), enzyme activity increased with increasing IPTG concentrations. At higher IPTG
concentrations (0.2 and 0.5 mM), enzyme activity declined progressively. Examination of induced recombinant E. coli cells by transmission electron microscopy showed the presence of only periplasmic inclusion bodies at low IPTG concentrations
(up to 0.1 mM) and both periplasmic and cytoplasmic inclusion bodies at high IPTG concentrations (0.2 mM and 0.5 mM). Results
from sodium dodecyl sulfate/polyacrylamide gel electrophoresis and immunoblots of whole-cell proteins, membrane proteins and
inclusion body proteins in these cells indicated that cytoplasmic inclusion bodies constituted an accumulation of preproenzyme
(i.e., precursor polypeptide containing a signal peptide) and that periplasmic inclusion bodies constituted an accumulation
of proenzyme (i.e., precursor polypeptide lacking a signal peptide).
Received: 27 March 1996 / Received revision: 2 July 1996 / Accepted: 10 November 1996 相似文献
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Prajoubklang A Sirithunyalug B Charoenchai P Suvannakad R Sriubolmas N Piyamongkol S Kongsaeree P Kittakoop P 《化学与生物多样性》2005,2(10):1358-1367
Deoxypreussomerin derivatives, palmarumycins JC1 (1) and JC2 (2), and two dimeric naphthoquinones, isodiospyrin (3) and its new derivative isodiospyrol A (4), were isolated from dried fruits of Diospyros ehretioides. Structures of the isolated compounds were elucidated by spectroscopic analyses. Palmarumycins were not found in the extract of freshly collected fruits; however, they were present in dried fruit extract. The absence of palmarumycins in fresh fruits of D. ehretioides, together with the chemotaxonomic point of view, we proposed that palmarumycins JC1 (1) and JC2 (2) are more likely to be fungal metabolites, i.e., endophytes or epiphytes. The isolation of palmarumycins 1 and 2 from dried D. ehretioides fruits could be reproducible; both plant samples collected in the years 2002 and 2004 provided the same result, and, therefore, symbiont fungal strains should be specific to the plant host, D. ehretioides, and they can grow on the fruits during drying the sample. Palmarumycin JC1 (1) did not exhibit antimalarial, antifungal, antimycobacterial, and cytotoxic activities. Palmarumycin JC2 (2) exhibited antimalarial (IC50 4.5 microg/ml), antifungal (IC50 12.5 microg/ml), antimycobacterial (MIC 6.25 microg/ml), and cytotoxic (IC50 11.0 microg/ml for NCI-H187 cell line) activities. In our bioassay systems, isodiospyrin (3) did not exhibit antimycobacterial, antifungal, antimalarial, and cytotoxic activities. Isodiospyrol A (4) exhibited antimalarial (IC50 2.7 microg/ml) and antimycobacterial (MIC 50 microg/ml) activities, but was inactive towards Candida albicans. Compound 4 also exhibited cytotoxicity against BC cells (IC50 12.3 microg/ml), but not towards KB and Vero cell lines. 相似文献
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Narukjaporn Thammajaruk Nongluksna Sriubolmas Duangnate Israngkul Vithaya Meevootisom Suthep Wiyakrutta 《Journal of industrial microbiology & biotechnology》2011,38(6):679-685
Culture media and fermentation conditions for cultivation of an endophytic fungus Phomopsis sp. Hant25 were investigated in order to improve the yield of mycoepoxydiene, a novel fungal metabolite having potent cytotoxic
activity against many cancer cell lines. Mycoepoxydiene accumulated in the culture broth during the stationary phase of fungal
growth. Modified M1D medium was superior to malt Czapek, and Czapek yeast autolysate broths in supporting mycoepoxydiene production.
Pellet growth was the morphological form that favored biosynthesis of mycoepoxydiene. This could be achieved by incubating
the culture statically for 6 days before shaking at 120 rpm. Incorporation of a cellulose paper disc into the culture flask
promoted fungal growth at the liquid surface, which accelerated mycoepoxydiene production and maximized the final yield to
a level of 354 mg l−1, though fungal attachment to the solid support was not required. Since the peak concentration of mycoepoxydiene in the culture
broth was followed by a steeply declining phase, the harvest time had to be precisely determined for maximum product yield.
Understanding the factor(s) involved in rapid degradation of mycoepoxydiene could lead to improved final yields. 相似文献
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Wiyakrutta Suthep Sriubolmas Nongluksna Panphut Wattana Thongon Nuntawan Danwisetkanjana Kannawat Ruangrungsi Nijsiri Meevootisom Vithaya 《World journal of microbiology & biotechnology》2004,20(3):265-272
A total of 81 Thai medicinal plant species collected from forests in four geographical regions of Thailand were examined for
the presence of endophytic fungi with biological activity. Of 582 pure isolates obtained, 360 morphologically distinct fungi
were selected for cultivation on malt Czapek broth and yeast extract sucrose broth, from which extracts were tested for biological
activity. Extracts of 92 isolates could inhibit Mycobacterium tuberculosis (MIC 0.0625–200 μg ml−1) when tested by the microplate Alamar blue assay, while extracts of six inhibited Plasmodium falciparum (IC50 of 1.2–9.1 μg ml−1) as determined by the [3H]hypoxanthine incorporation method. Strong anti-viral activity against Herpes simplex virus type 1 was observed in 40 isolates
(IC50 of 0.28–50 μg ml−1). The sulphorhodamine B assay for activity against cancer cell lines revealed that 60 were active against human oral epidermoid
carcinoma cells (EC50 0.42–20 μg ml−1) and 48 against breast cancer cells (EC50 0.18–20 μg ml−1). Bioactivity profile was affected by the type of culture medium. Given the high incidence of bioactive extracts and the
fact that most of the isolated fungi could not be identified due to lack of spore formation, the results suggested that Thai
medicinal plants can provide a wide variety of endophytes that might be a potential source of novel bioactive compounds.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Jatuporn Phaopongthai Suthep Wiyakrutta Duangdeun Meksuriyen Nongluksna Sriubolmas Khanit Suwanborirux 《Journal of microbiology (Seoul, Korea)》2013,51(6):821-828
In this study, a tropical endophytic fungus, Alternaria alternata Tche-153 was isolated from a Thai medicinal plant Terminalia chebula Rezt. The ethyl acetate extract prepared from the fermentation broth exhibited significant ketoconazole-synergistic activity against Candida albicans. Bioassay-directed fractionation of the ethyl acetate extract led to the isolation of altenusin (1), isoochracinic acid (2), and altenuic acid (3) together with 2,5-dimethyl-7-hydroxychromone (4). Using the disc diffusion method and the microdilution chequerboard technique, only altenusin (1) in combination with each of three azole drugs, ketoconazole, fluconazole or itraconazole at their low sub-inhibitory concentrations exhibited potent synergistic activity against C. albicans with the fractional inhibitory concentration index range of 0.078 to 0.188. This first discovery of altenusin (1) as a new azole-synergistic prototype possessing a biphenyl structure is of significance for further development of new azole-synergists to treat invasive candidiasis. 相似文献
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