Identification and real‐time qPCR quantification of a nitrite‐N degrading bacterial strain in aquatic water |
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| Authors: | Zhenzhen Su Yun Li Luqing Pan Jiashun Zhang |
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| Affiliation: | The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China |
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| Abstract: | Biological nitrogen removal technology using microbe is an efficient process for nitrogen removal from aquatic water. To determine the key of efficient application on how the effect of probiotics lasting, a nitrite nitrogen (nitrite‐N) degrading 8DO17 strain Pseudomonas was screened and a method for quantification was explored. Real‐time qPCR assays based on the 16S rRNA genes (16S rDNA) were used to quantify the probiotics. The results showed that (i) the nitrite‐N degradation rate of the 8DO17 strain was 99%; (ii) a wide spectrum of pH (7.0–9.0) and concentration of nitrite‐N (0.5–10 mg L?1) and the highest rate of nitrite‐N degradation near to 100% under optimum conditions (35°C, salinity 30, pH 7.5) was explored; (iii) no significant differences were found in the survival, total haemocyte count, antibacterial activities and bacteriolytic activity of the shrimp between the treatments and the control (P > 0.05); (iv) for the use of real‐time PCR based on 16S rDNA test, detection limit is 103 DNA copies and an excellent correlation coefficients (R² = 0.999) was obtained; and (v) in the application of real‐time PCR assay in four nitrite‐N degrading samples, highly significant positive correlation relation (P < 0.01) was found between log copy number of 16S rDNA and the rate of nitrite‐N degradation. The results suggest the real‐time PCR is a very rapid and sensitive technique for monitoring the dynamic changes and assessing the effect in practical application of the 8DO17 strain in aquatic water. |
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| Keywords: | real‐time qPCR quantification Pseudomonas probiotic nitrite‐N |
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