[Universality and Potential Application of Mn(â ¡) Oxidation Triggered by Microbial Interspecies Interactions].

Mn(Ⅱ)-oxidizing microorganisms can catalytically increase the oxidation rate of divalent manganese by several orders of magnitude, and affect the valence state and fate of elemental manganese. In addition to Mn(Ⅱ)-oxidization by a single microbial strain, our previous studies revealed that interspecies interactions between two bacterial strains (Sphingopyxis sp. QXT-31 and Arthrobacter sp. QXT-31) could trigger the Mn(Ⅱ)-oxidizing activities of Arthrobacter sp. QXT-31. In order to further explore its universality, mechanism, and potential engineering applications, research was conducted on three other Sphingopyxis strains using culture-dependent experiments, comparative genomic analysis, and transcriptome analysis. The results showed that one Sphingopyxis strain could also trigger the Mn(Ⅱ)-oxidizing activity of Arthrobacter sp. QXT-31, which could be regarded as a hint for the prevalence of Mn(Ⅱ) oxidation triggered by microbial interspecies interactions in the natural environment. Furthermore, the upregulation of the antibiotic synthesis pathway in Sphingopyxis was observed just before the Mn(Ⅱ)-oxidizing activity of Arthrobacter sp. QXT-31 was triggered, thus suggesting its possible involvement in stimulating the Mn(Ⅱ)-oxidizing activity of Arthrobacter sp. QXT-31. Finally, we demonstrated that using microbial interspecies interactions to enhance the oxidative removal of Mn(Ⅱ) in a manganese removal reactor is potentially feasible.

[Removal of Organic Matter from Water by Chemical Preoxidation Coupled with Biogenic Manganese Oxidation].

In the process of drinking water treatment, potassium permanganate and iron-manganese oxides are typical pre-oxidation methods that can not only effectively remove organic matters in drinking water, but also reduce the production of disinfection by-products (DBPs). However these two pre-oxidation methods will produce Mn2+ that is genotoxic. In order to solve this problem, a concept was proposed to connect biogenic-manganese oxidation technology after chemical oxidation. The manganese-oxidizing microbe may convert Mn2+ into the bio-manganese oxide, which can further remove the pollutants by its strong oxidative and adsorption capacity to improve water purification. In the simulated contaminated water composed of natural organic tyrosine (Tyr) and synthetic organic 2-Hydroxy-4-Methoxybenzophenone-5-Sulfonic Acid (BP-4), we verified the proposed the concept. Pre-oxidation by potassium permanganate or iron-manganese oxides efficiently removed Tyr, but had negligible effect on BP-4. During this, Mn2+ was generated. In the subsequent biological system, the manganese-oxidizing bacteria Pseudomonas sp. QJX-1 could utilize the Tyr for growth and oxidize Mn2+ to Mn4+ oxide. The generated manganese oxides could then effectively remove BP-4. In comparison, the moderate potassium permanganate preoxidation coupled with bio-manganese oxidation had a desirable treatment effect, with 100%, 50%, and 98.9% removals for Tyr, BP-4, and Mn2+, respectively. Importantly, the study provides a new method for drinking water treatment.

[Competitive Microbial Oxidation and Reduction of Arsenic].

Filters are widely applied in drinking water treatment plants. Our previous study, which explored the asenic redox in a filter of drinking water plant treating underground water, found that As3+ could be oxidized to As5+ by biogenic manganese oxides, while As5+ could be reduced to As3+ by some microbial arsenic reductases in the biofilter system. This microbial competition could influence the system stability and treatment efficiency. To explore its mechanism, this study selected a manganese-oxidizing bacterial strain (Pseudomonas sp. QJX-1) and a arsenic-reducing strain (Brevibacterium sp. LSJ-9) to investigate their competitive relationship in nutrient acquisition and arsenic redox in the presence of Mn2+, As3+ or As5+ The results revealed that the concentration and valence of Mn and As varied with different reaction time; biological manganese oxides dominated the arsenic redox by rapidly oxidizing the As3+ in the existing system and the As3+ generated by arsenic reductase into As. PCR and RT-PCR results indicated that the arsenic reductase (arsC) was inhibited by the manganese oxidase (cumA). The expression of 16S rRNA in QJX-1 was two orders of magnitude higher than that in LSJ-9, which implied QJX-1 was dominant in the bacterial growth. Our data revealed that hydraulic retention time was critical to the valence of arsenic in the effluent of filter in drinking water treatment plant.

[Application of FCM-qPCR to Quantify the Common Water Pathogens].

In the past, fecal E. coli was always regarded as the indicator organism for estimation of pathogens in water. However, a weak relation between fecal E. coli and water viruses or bacterial pathogens has been demonstrated by previous studies. Therefore, for water pathogen study, it is essential to select and quantify typical pathogens. In this study, a combination of quantitative PCR ( qPCR) with flow cytometry (FCM) was established to detect the concentrations of viruses, bacteria and several typical pathogens (e.g., E. coli, Legionnella, HAdV, Giardia, Cryptosporidium) in water. The method was applied to measure the pathogen concentrations in the influent and effluent of a wastewater treatment plant (WWTP), as well as its receiving river. The results revealed that the WWTP treated the pathogens with high removal efficiency ( > 93%); the effluent of WWTP did not show a negative effect on pathogen concentration of the receiving river. The study provides a technical support for the evaluation of WWTP treatment effect and the ecological impact of WWTP effluent on receiving river.

[Application of FISH-NanoSIMS technique in environmental microbial ecology study].

With the development of microbial ecology techniques, it is possible to analyze the distribution and function of microorganisms simultaneously in complex ecosystems. To explore the application of FISH-NanoSIMS in environmental microbial ecology study, our study used the stable isotope labeled compounds 13C-C6H12O6, and 15N-NH4Cl as C and N sources for cultivating the pure culture (manganese oxidizing bacteria, Pseudomonas sp. QJX-1) and environmental samples (the shallow soil and anaerobic sludge). FISH-NanoSIMS was used to detect the distribution of microorganisms and relatively quantify secondary ions (12C-, 13C-, 12C(14)N-, 12C15N-) in cultivated samples, in order to explore the utilization of C and N isotopes sources by the pure culture and microorganisms in environment samples. The results showed that the contents of 13C and 5N in the area of bacteria were significantly greater than the natural abundance in all samples. It indicated that Pseudomonas sp. QJX-1 and some specific bacteria in environmental samples could metabolize 13C-C6H12O6 and 15N-NH4C1. Furthermore, this study revealed that for Pseudomonas sp. QJX-1, the manganese oxidation only occurred when the carbon and nitrogen were consumed to a low level. For environmental samples, the bacterial nitrification and denitrification were both observed in the shallow soil and anaerobic sludge. In a word, our study demonstrated that the combination of FISH and NanoSIMS could simultaneously examine microbial distribution and microbial metabolic activity in environmental samples, which will help us to obtain the eco-physiology information of microbial community.

[Characterization of manganese oxidation by Pseudomonas sp. QJX-1].

A manganese-oxidizing bacteria (QJX-1) was isolated from the soil of a manganese mine. It was identified as Pseudomonas sp. QJX-1 by 16S rDNA sequencing. Experimental results showed that the Pseudomonas sp. QJX-1 has a multi-copper oxidase gene CumA, which is an essential component for manganese oxidation by Pseudomonas sp. Under the condition of low initial inoculum level (D600, 0.020), 5.05 mg x L(-1 Mn2+ could be oxidized by QJX-1 within 48 h with a conversion rate of as high as 99.4%. In comparison with the eutrophic conditions, the oligotrophic condition dramatically increased the biological manganese oxidation rate. Biofilm formation by employing the quartz sand could further improve the oxidation rate of Mn2+. Based on these results, it is speculated that biological manganese oxidation in underground water treatment is comparatively high.

[Effects of warm needle moxibustion on bone mass density and biochemical indexes of bone metabolism in patients of postmenopausal osteoporosis].

OBJECTIVE: To compare therapeutic effects of warm needle moxibustion and medication on osteoporosis and to study the mechanism. METHODS: Forty cases were randomly divided into an acupuncture group and a medication group, 20 cases in each group. The acupuncture group was treated by warm needle moxibustion at Dazhu (BL 11), Ganshu (BL 18), Shenshu (BL 23), Zusanli (ST 36), Yanglingquan (GB 34) etc. once other day, for 3 months; and the medication group was treated by oral administration of tablet Caltrate with Vit D2 for 3 months. The changes of bone mass density (BMD), estradiol (E2), osteocalcin (bone growth protein, BGP), urine calcium/creatinine (Ca/Cr) in the two groups before and after treatment and therapeutic effects were investigated. RESULTS: After treatment, BMD significantly increased (P<0.05, P<0.01) in the acupuncture group and did not signifi cantly changed in the medication group (P>0.05) with a significant difference between the two groups (P<0.05). After treatment E2 level significantly increased as compared with before treatment in both of groups (P<0.01); after treatment BGP significantly decreased as compared with before treatment in both of groups (P<0.01); after treatment Ca/Cr significantly decreased as compared with before treatment in the acupuncture group (P<0.05) ; af ter treatment, there were significant differences in BGP and Ca/Cr between the two groups (P<0.05 or P<0.01). The clinically controlled rate in the acupuncture group and in the medication group were 35.0%, 5.0%, respectively, the therapeutic effect of the acupuncture group being better than that of the medication group (P<0.01). CONCLUSION: The therapeutic effect of warm needle moxibustion on osteoporosis is better than that of oral administration of tablet Caltrate with Vit D2 and it can increase levels of hormones and delay bone loss. It is an effective method for preventing and treating postmenopausal osteoporosis.