[PDF][PDF] A threshold selection method from gray-level histograms

N Otsu - Automatica, 1975 - dspace.tul.cz
N Otsu
Automatica, 1975dspace.tul.cz
Summary 16S rRNA-targeted oligonucleotide probes for eubacteria (EUB338), ammonium-
oxidizing bacteria (Nsm156) and nitrite-oxidizing bacteria (Nb1000) were used for the rapid
detection of nitrifying bacteria in the activated sludge of a pilot nitrifying reactor by whole-
cell, fluorescent in situ hybridization (FISH). Emission scanning and synchronous scanning
fluorescence spectrometry were used to measure the hybridization. The binding of the
probes at a temperature significantly lower than the melting temperature of the hybrids was …
Summary
16S rRNA-targeted oligonucleotide probes for eubacteria (EUB338), ammonium-oxidizing bacteria (Nsm156) and nitrite-oxidizing bacteria (Nb1000) were used for the rapid detection of nitrifying bacteria in the activated sludge of a pilot nitrifying reactor by whole-cell, fluorescent in situ hybridization (FISH). Emission scanning and synchronous scanning fluorescence spectrometry were used to measure the hybridization. The binding of the probes at a temperature significantly lower than the melting temperature of the hybrids was conventionally considered as nonspecific. Total binding of the probes at a temperature significantly higher than the melting temperature of the hybrids was conventionally considered as the sum of non-specific and specific binding (hybridization). Non-specific binding of the oligonucleotide probes with a biomass of activated sludge was 37% of the total binding of the EUB338 probe, 54% of the total binding of the Nsm156 probe, and 69% of the total binding of the Nb1000 probe. The ratio of the specific binding of the Nsm156 and Nb1000 probes was 2.3: 1. The ratio of the numbers of ammonium-oxidizing bacteria to nitrite-oxidizing bacteria, determined by microbiological methods, was 2.4: 1. Measuring fluorescent in situ hybridization by fluorescence spectrometry appears to be a practical tool for monitoring the microbial communities that contain nitrifying bacteria. However, a method that accounts for the non-specific binding of the probes more easily and reliably should be developed for practical application.
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