Revealing The Diversity And Quantity Of Peritirch Ciliates In Environmental Samples Using Specific Primer

Peritrichs are a diverse, ecologically important ciliate group usually with acomplex life cycle. To date, the community of the peritrichs has been investigated byusing morphology-based methods such as living observation and silver staining. Herewe show a molecular approach for characterizing the diversity and quantity offree-living peritrichs in environmental samples.We designed four new peritrich-specific primers targeting18S rRNA genes thatallow clone library construction, screening and analysis. A quantitative real-time PCR(qPCR) assay was developed to quantify peritrichs in the environmental samples byusing rDNA copy numbers as an indicator. DNA extracted from four water samplesfrom sites of contrasting environmental gradients was analysed. The results showeddifferentiated peritrich community among samples, and decreased diversity with theincrease of water salinity. The qPCR results are consistent with the library sequenceanalysis in terms of quantity variations from sample to sample.The development of peritrich-specific primers, for the first time, for conventionalPCR and qPCR assays, provides useful molecular tools for revealing the diversity andquantity of peritrich ciliates in environmental samples. Also, our study illustrates thepotential of these molecular tools to ecological studies of other ciliate groups indiverse environments.