皮炎外瓶霉的核糖体基因研究

Population studies of Exophiala dermatitidis by PCR-RFLP and sequence analysis in the ribosomal DNA

目的 :探讨不同来源、不同致病性的皮炎外瓶霉在基因学上是否具有差异性。方法 :试验菌株包括皮炎外瓶霉 1 6株 (模式株、标准株、临床及自然分离株 ) ,甄氏外瓶霉 1株 (标准株 ) ,丛梗孢外瓶霉 1株 (临床株 )。煮沸冷冻法提取DNA ,常规PCR扩增核糖体基因及其转录间隔区 ,应用限制性片段长度多态性、DNA多序列分析方法等进行研究。结果 :皮炎外瓶霉核糖体基因及其转录间隔区较为保守 ,PCR RFLP对于该菌种的鉴定具有较大意义 ;DNA序列分析显示 ,不同来源、不同致病性的皮炎外瓶霉分属于不同的生物群落 ,提示不同群落致病性的差异存在一定的遗传学基础。结论 :皮炎外瓶霉核糖体基因及其转录间隔区序列保守 。

SUMMARY Objective: To detect the gene discrepancy of E. dermatitidis strains and other species from diverse sources. Methods: Tested strains included 16 isolates of E. dermatitidis (type culture, reference culture, clinical and environmental isolates), 1 isolate of E. jeanselmei (reference strain) and E. moniliae (clinical isolate) respectively. DNA was isolated with boiled water method. Ribosomal DNA and its internal transcribed spacer regions were amplified and analyzed with restricted fragment length polymorphism and sequencing. Results: The ribosomal genes of E. dermatitidis were quite conservative. E. dermatitidis was successfully identified by means of restricted fragment length polymorphism method. Multiple sequence analysis showed that E. dermatitidis isolates from different sources remained with respective populations, which revealed their genetic discrepancies to some extent. Conclusion: The ribosomal RNA genes and their internal transcript sequences are quite conservative, which is meaningful in the taxonomy of this kind of species.