Rao S K, Achar P N
Department of Biochemistry, University of the Western Cape, Bellville, Cape Town, South Africa.
Indian J Exp Biol. 2001 Dec;39(12):1243-8.
Stenocarpella maydis from different maize growing regions in South Africa were collected and screened for the presence of diplodiatoxin. The presence of diplodiatoxin in these isolates was detected by thin layer chromatography and further confirmed by atomic pressure chemical ionization mass spectrometry. Samples containing diplodiatoxin showed a strong positive ion at m/z=307. MC34, MC35, MC43 and MC50 isolates of Potchefstroom region produced high amount of diplodiatoxin, whereas some of the isolates from Potchefstroom (D72, D74, D78, D79 and D80) and Cedara (CH3 and U3H) regions did not contain diplodiatoxin. Experiments were conducted to optimize in vitro production of diplodiatoxin using the isolate MC 43. A varied range of pH (3.0 to 5.0) and various culture media viz., PDB, CME, CLM and MSM were tested. Growth of mycelium and production of diplodiatoxin was maximum in PDB media at pH 4.5 and it was observed that diplodiatoxin was produced in detectable quantity in the cultures older than 6 weeks in this media. Further, diplodiatoxin was isolated and purified from 8-weeks-old cultures of MC43 isolate and confirmed by nuclear mass resolution. The standard and the compound purified showed similar NMR spectrum. Sixty-gram (fresh weight) mycelium yielded 19.52 mg of diplodiatoxin. Effect of diplodiatoxin on the growth of various bacterial strains in agar-gelled LB media was studied. They showed different range of tolerance to diplodiatoxin. The increasing order of tolerance to diplodiatoxin was Stenocarpella maydis < B. cereus < B. subtulus < P. fluorescense < E. coli. Further, the effect of different concentrations (4.88-49.70 microg/mL) of diplodiatoxin on the growth of S. aureus in LB liquid media was studied. Presence of diplodiatoxin in the media reduced cell growth as compared to the control thus, confirming anti-bacterial activity of diplodiatoxin.
从南非不同玉米种植区采集了玉米窄叶斑病菌，并对其进行了双二乙嗪毒素检测。通过薄层色谱法检测这些分离菌株中双二乙嗪毒素的存在，并通过原子压力化学电离质谱法进一步确认。含有双二乙嗪毒素的样品在m/z=307处显示出强正离子。波切夫斯特鲁姆地区的MC34、MC35、MC43和MC50分离株产生大量双二乙嗪毒素，而波切夫斯特鲁姆地区（D72、D74、D78、D79和D80）和塞达拉地区（CH3和U3H）的一些分离株不含有双二乙嗪毒素。进行了实验以优化使用分离株MC 43体外生产双二乙嗪毒素的条件。测试了不同范围的pH值（3.0至5.0）和各种培养基，即马铃薯葡萄糖肉汤（PDB）、玉米粉提取物（CME）、酪蛋白水解物培养基（CLM）和麦芽汁培养基（MSM）。在pH 4.5的PDB培养基中，菌丝体生长和双二乙嗪毒素产量最高，并且观察到在该培养基中培养6周以上的培养物中可检测到双二乙嗪毒素。此外，从MC43分离株8周龄的培养物中分离并纯化了双二乙嗪毒素，并通过核磁共振质量分辨率进行了确认。标准品和纯化的化合物显示出相似的核磁共振谱。60克（鲜重）菌丝体产生了19.52毫克双二乙嗪毒素。研究了双二乙嗪毒素对琼脂凝胶化LB培养基中各种细菌菌株生长的影响。它们对双二乙嗪毒素表现出不同程度的耐受性。对双二乙嗪毒素耐受性的递增顺序为玉米窄叶斑病菌＜蜡样芽孢杆菌＜枯草芽孢杆菌＜荧光假单胞菌＜大肠杆菌。此外，研究了不同浓度（4.88 - 49.70微克/毫升）的双二乙嗪毒素对LB液体培养基中金黄色葡萄球菌生长的影响。与对照相比，培养基中双二乙嗪毒素的存在降低了细胞生长，从而证实了双二乙嗪毒素的抗菌活性。
