Garcés G, Effenberger M, Najdrowski M, Wackwitz C, Gronauer A, Wilderer P A, Lebuhn M
Institute for Water Quality Control, Technical University of Munich, Am Coulombwall, 85748 Garching, Germany.
Water Sci Technol. 2006;53(8):195-202. doi: 10.2166/wst.2006.250.
The survival of Cryptosporidium parvum oocysts in anaerobic digesters treating manure was investigated for mesophilic, thermophilic, and a combined treatment (mesophilic-thermophilic-mesophilic) under different retention times of oocysts in the reactors. C. parvum DNA was extracted with an optimised protocol, and its amount determined by quantitative real-time PCR (qPCR). Results indicated noteworthy differences in DNA content after the different treatments. DNA was not degraded during the process. However, excystation and infectivity tests showed a reduction of viable oocyst numbers of > or = 2 and > or = 5 log units after the thermophilic treatment in two different experiments. Thus qPCR-targeting DNA can overestimate the number of oocysts that survive and remain viable after anaerobic digestion. However, targeting DNA is suitable to indicate the presence or absence of oocysts. Reverse transcription qPCR (RT-qPCR) targeting C. parvum hsp70 mRNA successfully indicated the presence of viable fraction of oocysts.
研究了在不同的隐孢子虫卵囊在反应器中的停留时间下，厌氧消化器处理粪便时微小隐孢子虫卵囊的存活情况，实验设置了中温、高温以及联合处理（中温-高温-中温）三种条件。采用优化方案提取微小隐孢子虫DNA，并通过定量实时PCR（qPCR）测定其含量。结果表明不同处理后DNA含量存在显著差异，且在此过程中DNA未被降解。然而，脱囊和感染性试验表明，在两个不同实验的高温处理后，存活卵囊数量减少了≥2个对数单位和≥5个对数单位。因此，靶向DNA的qPCR可能高估厌氧消化后存活且仍具活力的卵囊数量。不过，靶向DNA适用于指示卵囊的存在与否。靶向微小隐孢子虫hsp70 mRNA的逆转录qPCR（RT-qPCR）成功地指示了存活卵囊部分的存在。
