中华皮肤科杂志 ›› 2008, Vol. 41 ›› Issue (8): 515-518.

• 论著 • 上一篇    下一篇

土壤中暗色真菌分离方法的研究

胡晓艳 席丽艳 鲁长明 董琛 鲁莎   

  1. 中山大学附属第五医院 广州市中山大学附属第二医院皮肤科 广州中山大学附属第二医院皮肤科 太原市山西医科大学第二医院皮肤性病科
  • 收稿日期:2007-08-29 修回日期:2007-12-18 发布日期:2008-08-15
  • 通讯作者: 胡晓艳 E-mail:xiaoyanhu5@yahoo.com.cn

Evaluation of methods for isolation of dematiaceous fungi from soil

HU Xiao-Yan   

  • Received:2007-08-29 Revised:2007-12-18 Published:2008-08-15
  • Contact: HU Xiao-Yan E-mail:xiaoyanhu5@yahoo.com.cn

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摘要： 目的 寻找经济有效的土壤中暗色真菌的分离方法。方法 将一份含有暗色真菌的土壤样品悬液10倍比稀释成4个浓度，并配成含抗生素和不含抗生素2组，8支样品液分别接种于沙氏葡萄糖蛋白胨培养基（SDA）、马铃薯葡萄糖琼脂培养基（PDA）、孟加拉红培养基，各培养基含有0，100，200，300，500 mg/L 5个浓度的放线菌酮和100万U/L青霉素，50 mg/L氯霉素，200 mg/L链霉素，分别采用涂布法与倾注法培养，每种培养基共接种80个平皿。结果 三种培养基的分离效率分别为：PDA 70%，孟加拉红67.5%，SDA 3.75%。土壤液稀释100倍和培养基中放线菌酮质量浓度为200 mg/L时的分离效率最高，土壤液原液和稀释100倍时分离效率在PDA分别为50%和85%，两组比较，P ＜ 0.05；在孟加拉红培养基分别为45%和85%，两组比较，P ＜ 0.05。各培养基中无放线菌酮和放线菌酮质量浓度为200 mg/L时分离率分别为PDA 31.25%和87.5%，两组比较，P ＜ 0.05；孟加拉红培养基分别为37.5%和81.25%，两组比较，P ＜ 0.05。样本液中加抗生素和不加抗生素分离率比较，差异无统计学意义。各培养基涂布法与倾注法比较，总的分离率差异无统计学意义，但样品液中不加放线菌酮等抗生素时，倾注法比涂布法分离效率高，PDA分别为80%和40%，孟加拉红分别为80%和30%，各自比较差异均有统计学意义（P ＜ 0.05）。结论 改良的马铃薯、孟加拉红培养基是适合土壤中暗色真菌分离的培养基，培养基中放线菌酮浓度为200 mg/L为最适浓度，采用倾注平板法时方便、经济、有效。

关键词: 土壤, 暗色真菌, 分离

Abstract: Objective To seek a cost-effective method for isolation of dematiaceous fungi from soil. Methods Four concentrations of soil suspension samples were prepared by ten-fold serial dilution （1, 1 ∶ 10, 1 ∶ 100, 1 ∶ 1000）. Then, each concentration of sample was divided into two parts: one part supplemented with antibiotics, including chloramphenicol, cycloheximide, penicilin and streptomycin, and the other free of antibiotics. Three culture media were prepared: Sabouraud′s dextrose agar（SDA）, potato dextrose agar（PDA） and rose bengal medium （RBM）. Various concentrations （0, 100, 200, 300, 500 mg/L） of cycloheximide were added into each culture medium along with defined concentration of penicillin （1000 u/mL） and streptomycin （0.2 g/L）. In addition, chloramphenicol （50 mg/L） was added to PDA. The prepared soil samples were inoculated into these media by spread plate and pour plate, respectively. Results The total isolation rate of dematiaceous fungi was 70% （56/80） for PDA, 67.5% （54/80) for RBM and 3.75% （3/80） for SDA. PDA and RBM were more efficient than SDA （both P < 0.05）. Significant difference was observed in the isolation rate of dematiaceous fungi between the original and 1:100 diluted soil suspension samples in PDA （50% vs 85%, P < 0.05） and RBM （45% vs 85%, P < 0.05）. An increased isolation rate was achieved in PDA （87.50% vs 31.25%） and RBM （81.25% vs 37.5%） with cycloheximide at 200 mg/L compared with those free of cycloheximide. No difference was found in the isolation rate between antibiotic-supplemented and antibiotic-free soil samples. Although there was no difference in the total isolation rate between spead plate and pour plate, a higher isolation rate was observed by pour plate from antibiotic-free soil samples in PDA （80% vs 40%, P < 0.05） and RBM （80% vs 30%, P < 0.05） compared with spread plate. Conclusions The modified PDA and RBM are suitable for the isolation of dematiaceous fungi from soil with the optimal concentration of cycloheximide being 200 mg/L in the medium. Pour plate is more convenient and cost-effective than spread plate for the isolation of dematiaceous fungi from soil.

Key words: Soil, Dematiaceae fungi, Isolation