Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium （NH4^＋-N）. In order to further understand its remo...Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium （NH4^＋-N）. In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at different carbon to nitrogen （C/N） mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions （C/N 10, 30℃, 120 r/min）, YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine （NHzOH）, nitrite （NO2^-） and nitrate （NO3^-） as well as the denitrification product, nitrogen gas （N2）, were detected under completely aerobic conditions.展开更多
Tri(2-chloropropyl)phosphate(TCPP)was an emerging contaminant of global concern because of its frequent occurrence,potential toxic effects,and persistence in the environment.Microbial degradation might be an efficient...Tri(2-chloropropyl)phosphate(TCPP)was an emerging contaminant of global concern because of its frequent occurrence,potential toxic effects,and persistence in the environment.Microbial degradation might be an efficient and safe removal method,but limited information was available.In this study,Providencia rettgeri was isolated from contaminated sediment and showed it could use TCPP as unique phosphorus source to promote growth,and decompose 34.7%of TCPP(1 mg/L)within 5 days.The microbial inoculation and the initial concentration of TCPP could affect the biodegradation efficient.Further study results indicated that TCPP decomposition by Providencia rettgeri was mainly via phosphoester bond hydrolysis,evidenced by the production of bis(2-chloropropyl)phosphate(C_(6)H_(13)Cl_(2)PO_(4))and mono-chloropropyl phosphate(C_(3)H_(8)ClPO_(4)).Both intracellular and extracellular enzymes could degrade TCPP,but intracellular degradation was dominant in the later reaction stage,and the presence of Cu^(2+) ions had a promoting effect.These findings developed novel insights into the potential mechanism of TCPP microbial degradation.展开更多
利用PCR和分子克隆技术从雷氏普罗威登斯菌(Providencia rettgeri)(ATCC29944)的基因组DNA中获得一个青霉素G酰化酶(penicillin G acylase,PGA)基因并将其装入表达质粒pET24a。携带有重组质粒pETPGA的Escherichia coli基因工程菌BL21(DE...利用PCR和分子克隆技术从雷氏普罗威登斯菌(Providencia rettgeri)(ATCC29944)的基因组DNA中获得一个青霉素G酰化酶(penicillin G acylase,PGA)基因并将其装入表达质粒pET24a。携带有重组质粒pETPGA的Escherichia coli基因工程菌BL21(DE3)/pETPGA实现了PGA的高效表达。对发酵条件的研究表明基因工程菌在24℃、添加5g/L甘油条件下以1.0mmol/L IPTG诱导1.5h酶活力即达到993.4U/L,比野生菌酶活力(15U/L)提高了66倍。展开更多
为了分离鉴定海南某养殖场黑山羊流鼻液、打喷嚏这一临床症状可能的致病菌,试验通过对病羊鼻拭子的无菌采集、病原菌分离培养后,利用革兰氏染色、细菌生化反应、细菌16S r RNA通用引物进行PCR反应等方法对分离得到的菌株进行鉴定。结果...为了分离鉴定海南某养殖场黑山羊流鼻液、打喷嚏这一临床症状可能的致病菌,试验通过对病羊鼻拭子的无菌采集、病原菌分离培养后,利用革兰氏染色、细菌生化反应、细菌16S r RNA通用引物进行PCR反应等方法对分离得到的菌株进行鉴定。结果表明:对病羊鼻拭子培养后,得到的菌落形态一致;通过染色发现该菌为短杆状革兰氏阴性菌,进一步鉴定该菌为雷氏普罗威登斯菌。可引起海南黑山羊呼吸道疾病,为相应疾病的诊断和治疗奠基了一定的基础。展开更多
基金supported by the National Natural Science Foundation of China (No 20676078)
文摘Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium （NH4^＋-N）. In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at different carbon to nitrogen （C/N） mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions （C/N 10, 30℃, 120 r/min）, YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine （NHzOH）, nitrite （NO2^-） and nitrate （NO3^-） as well as the denitrification product, nitrogen gas （N2）, were detected under completely aerobic conditions.
基金This work was supported by the Natural Science Foundation of Guangdong Province(No.2023A1515030284)the Key Realm Research and Development Program of Guangdong Province(No.2020B0202080001)+1 种基金the Guangdong Laboratory for Lingnan Modern Agriculture Project(No.NT2021010)the Science and Technology Planning Project of Guangdong Province(No.2021B1212040008).
文摘Tri(2-chloropropyl)phosphate(TCPP)was an emerging contaminant of global concern because of its frequent occurrence,potential toxic effects,and persistence in the environment.Microbial degradation might be an efficient and safe removal method,but limited information was available.In this study,Providencia rettgeri was isolated from contaminated sediment and showed it could use TCPP as unique phosphorus source to promote growth,and decompose 34.7%of TCPP(1 mg/L)within 5 days.The microbial inoculation and the initial concentration of TCPP could affect the biodegradation efficient.Further study results indicated that TCPP decomposition by Providencia rettgeri was mainly via phosphoester bond hydrolysis,evidenced by the production of bis(2-chloropropyl)phosphate(C_(6)H_(13)Cl_(2)PO_(4))and mono-chloropropyl phosphate(C_(3)H_(8)ClPO_(4)).Both intracellular and extracellular enzymes could degrade TCPP,but intracellular degradation was dominant in the later reaction stage,and the presence of Cu^(2+) ions had a promoting effect.These findings developed novel insights into the potential mechanism of TCPP microbial degradation.
文摘为了分离鉴定海南某养殖场黑山羊流鼻液、打喷嚏这一临床症状可能的致病菌,试验通过对病羊鼻拭子的无菌采集、病原菌分离培养后,利用革兰氏染色、细菌生化反应、细菌16S r RNA通用引物进行PCR反应等方法对分离得到的菌株进行鉴定。结果表明:对病羊鼻拭子培养后,得到的菌落形态一致;通过染色发现该菌为短杆状革兰氏阴性菌,进一步鉴定该菌为雷氏普罗威登斯菌。可引起海南黑山羊呼吸道疾病,为相应疾病的诊断和治疗奠基了一定的基础。
