Denitrifying phosphate accumulating organisms and its mechanism of nitrogen and phosphorus removal / 生物工程学报

Water eutrophication poses great threats to protection of water environment. Microbial remediation of water eutrophication has shown high efficiency, low consumption and no secondary pollution, thus becoming an important approach for ecological remediation. In recent years, researches on denitrifying phosphate accumulating organisms and their application in wastewater treatment processes have received increasing attention. Different from the traditional nitrogen and phosphorus removal process conducted by denitrifying bacteria and phosphate accumulating organisms, the denitrifying phosphate accumulating organisms can simultaneously remove nitrogen and phosphorus under alternated anaerobic and anoxic/aerobic conditions. It is worth noting that microorganisms capable of simultaneously removing nitrogen and phosphorus absolutely under aerobic conditions have been reported in recent years, but the mechanisms remain unclear. This review summarizes the species and characteristics of denitrifying phosphate accumulating organisms and the microorganisms capable of performing simultaneous nitrification-denitrification and phosphorous removal. Moreover, this review analyzes the relationship between nitrogen removal and phosphorus removal and the underlying mechanisms, discusses the challenges of denitrifying phosphorus removal, and prospects future research directions, with the aim to facilitate process improvement of denitrifying phosphate accumulating organisms.

Effect of electroacupuncture on 1-bromopropane-induced peripheral nerve damage in rats / 中国职业医学

OBJECTIVE: To investigate the therapeutic effect of electroacupuncture on peripheral nerve damage induced by 1-bromopropane( 1-BP) exposure.METHODS: A total of 25 specific pathogen free healthy adult male Wistar rats were randomly divided into blank control group( n = 5),model control group( n = 10),and electroacupuncture treatment( EA) group( n = 10).Rats in the blank control group were not exposed to 1-BP and treated with electroacupuncture.The rats in model control group and EA group were placed in a dynamic inhalation exposure cabinet with 1-BP at concentration of 5 000 mg/m~3.The rats were continuously exposed to 1-BP 8 hours per day,5 days a week,for 4 weeks.At the 3 rd day after the end of the exposure,the EA group was treated with electroacupuncture on“Zu sanli”and“Huantiao”points for 4 courses.Each course included 20 minutes each time,once per day for 7 consecutive days.The body weight,the motor nerve conduction velocity( MCV) and sense nerve conduction velocity( SCV) of sciatic nerves on both posterior limbs of the rats were measured.RESULTS: During the course of 1-BP exposure,the rats in the EA and model control group showed reduction of eating,drinking and activities,limited autonomic activities and their hind limbs dragged.The MCV and SCV of posterior limb sciatic nerve of rats in the model control group were slower than that of the control group at the 4 th,6th and 8th week and the 0 week of the same group( P < 0.05).The MCV and SCV of posterior limb sciatic nerve of rats in the EA group improved with the increase of treatment time( P < 0.05),and those at the 6th and 8th weeks of the experiment( corresponding to the 2nd and 4th week after treatment) were faster than that of the model control group at the same time( P < 0.05).The SCV of the posterior limb sciatic nerve in the EA group recovered to normal level 4 weeks after treatment compared with the blank control group( P < 0.05).CONCLUSION: Electroacupuncture treatment can promote the recovery of peripheral nerve damage in rats with 1-BP poisoning.