Dynamic characteristics of microbial community and soluble microbial products in partial nitrification biofilm system developed from marine sediments treating high salinity wastewater.

High salinity wastewater generally resulted in microorganism death and low treatment efficiency of nutrient in conventional activity sludge system. Marine sediments, containing a huge amount of natural salt-tolerant microorganisms, provide a feasible option for the rapid construction of halophilic biological treatment system. However, the dynamic of native microorganisms and the fate of soluble microbial products (SMP) in halophilic biofilm system developed from marine sediments needs to be further studied. In this study, a partial nitrification system was successfully established by inoculation of marine sediments in sequential batch biofilm reactor. Satisfactory chemical oxygen demand (COD) and NH4+-N removal efficiency (95% and 99%) and nitrite accumulation rate (NAR) (>90%) was achieved for treatment of synthetic seawater blackwater. High cell surface hydrophobicity (CSH) and proteins to polysaccharide ratio of extracellular polymeric substance (EPS) were beneficial to the initial biofilm formation. High-throughput sequencing results revealed Nitrosomonas halophila was the sole ammonia oxidizing bacteria (AOB). Thauera and Paracoccus were the main denitrifying bacteria in three biofilm samples. Excitation emission matrix (EEM) spectroscopy coupled with parallel factor analysis (PARAFAC) clarified that proteins were significantly degraded than the other two components (humic-like and fulvic acid-like substance). This study will provide a feasible approach for developing halophilic biological treatment system and present an in-depth insight of the dynamic characteristics of SMP in partial nitrification biofilm system.

Multidrug resistance and tumor-initiating capacity of oral cancer stem cells.

PURPOSE: Recent studies in several tumors showed that presence of cancer stem like side population (SP) cells are responsible for chemotherapeutic drugs resistance and tumor relapse. In our present study, we have analyzed the role of SP cells in oral squamous cell carcinoma cell (OSCC) line OSCC-77. METHODS: The oral cancer cell line OSCC-77 was analyzed for the presence of SP cells by FACS using Hoechst 33342 dye exclusion method. Further the FACS-sorted SP and non-SP cells were subjected to drug resistance and sphere formation assays. RESULTS: We identified that the presence of SP cells in OSCC-77 cell line was 3.4%, which was reduced to 0.6% in the presence of verapamil, an inhibitor of ABC transporter. Furthermore, we showed that these SP cells were highly drug-resistant, had increased survival and were highly potent for self-renewal. Also, the clone formation efficiency of SP cells was significantly higher compared to non-SP cells (p<0.01). CONCLUSION: Our data suggest that cancer stem-like SP cells of OSCC-77 cell line contribute to multidrug resistance and are highly involved in tumor relapse. However, further characterization of SP cells at gene expression level and their signaling pathways might provide new insights into the development of novel anticancer drugs.

Microbial community succession, species interactions and metabolic pathways of sulfur-based autotrophic denitrification system in organic-limited nitrate wastewater.

Elemental sulfur (S0) introduction could achieve the co-existence of heterotrophic denitrification (HDN) and autotrophic denitrification (ADN) in practical organic-limited nitrate wastewater treatment. Until now, changes in key functional species, metabolic pathways and microbial products in the succession process of microbialcommunities based on different of pollutant concentration and trophic conditions are still unclear. In present study, high-efficiency of total nitrogen (TN) removal achieved in S0-based ADN bioreactor at influent nitrate of 30-240 mg/L. Content of proteins and polysaccharides in extracellular polymeric substances (EPS) declined with nitrate loads increased. The key functional heterotrophic denitrifiers (Hyphomicrobium, Trichococcus, Rivibacter) and autotrophic biotope (Thiobacillus, Thiomonas, Ferritrophicum, Flavobacterium, Stenotrophomonas, Cloacibacterium and Pseudoxanthomonas) jointly contributed to high nitrogen removal efficiency at different nitrate loads. Furthermore, network analysis verified that symbiotic relationships accounted for the major proportion (88.3%) of the microbial network. The enhanced of nitrogen and sulfur metabolism improved nitrogen removal and S0-based autotrophic denitrification capacity.