Orange-spotted grouper Epinephelus coioides that have encountered low salinity stress have decreased cellular and humoral immune reactions and increased susceptibility to Vibrio alginolyticus.

Orange-spotted grouper Epinephelus coioides reared at 34‰ and 27 °C were abruptly transferred to 6‰, 20‰ and 34‰ (control) and examined for innate cellular and humoral parameters after 3-96 h. Total leucocyte count (TLC), respiratory burst (RB), phagocytic activity (PA), alternative complement pathway (ACP) and lysozyme activity were significantly decreased 3-6 h, 3-6 h, 3-96 h, 3-96 h and 3-96 h, respectively after transferal into 6‰ salinity. TLC, RB and PA significantly increased after 3-48 h, 3-96 h and 3-24 h, respectively, with recovery of TLC and PA after 96 h and 48-96 h, whereas ACP and lysozyme activity significantly decreased 3-96 h after being transferred to 20‰. In another experiment, grouper reared at 34‰ and 27 °C were injected with Vibrio alginolyticus grown in tryptic soy broth (TSB) at 2.3 × 109 colony-forming units (cfu) fish-1 and then transferred to 6‰, 20‰ and 34‰ (control). The cumulative mortalities of V. alginolyticus-injected fish held in 6‰ were significantly higher than in injected fish held at 20‰ and 34‰. It was concluded that grouper E. coioides encountering a 34‰-6‰ salinity drop stress exhibited a depression in immunity as evidenced by decreased cellular and humoral parameters and increased susceptibility to V. alginolyticus. Grouper encountering a salinity stress drop from 34‰ to 20‰, however, exhibited decreased humoral immune parameters but also increased TLC and cellular immune parameters, indicating immunomodulation.

Effects of temperature change on the innate cellular and humoral immune responses of orange-spotted grouper Epinephelus coioides and its susceptibility to Vibrio alginolyticus.

Orange-spotted grouper Epinephelus coioides held at 27 degrees C were then further cultured at 19, 27 (control), and 35 degrees C, and were examined for innate cellular and humoral responses after 3-96 h. The total leucocyte count, respiratory burst, and phagocytic activity significantly decreased 3, 48, and 96 h after fish were transferred to 19 and 35 degrees C. Both the alternative complement pathway (ACH(50)) and the lysozyme activity significantly decreased at 3-96 h after fish were transferred to 19 and 35 degrees C. In another experiment, groupers reared at 27 degrees C at 34 per thousand salinity were injected with Vibrio alginolyticus grown in tryptic soy broth (TSB) at a dose of 2.3 x 10(9) colony-forming units (cfu) fish(-1), and then further reared in water temperatures of 19, 27 (control), and 35 degrees C. The cumulative mortalities of V. alginolyticus-injected fish held in 19 and 35 degrees C were significantly higher than that of injected fish held in 27 degrees C. Resistance had decreased after 12 h for the challenged grouper held at 35 degrees C. All injected fish held in 19 degrees C had died after 72 h. It was concluded that at 12 h after transfer of grouper from 27 to 19 and 35 degrees C, immunity was suppressed and resistance against V. alginolyticus had decreased.

[Effects of Anode Materials on Electricity Generation and Organic Wastewater Treatment of 6 L Microbial Fuel Cells].

Anode material is one of the most important factors on the application of microbial fuel cells for wastewater treatment due to its key role in forming exoelectrogenic biofilm and transferring electrons along with the high investment cost. In this study, carbon brush (CB), carbon cloth (CC) and graphite felt (GF) were investigated as alternative anode materials for 6 L single-chamber dual air-cathode microbial fuel cells (MFCs) in terms of starting-up rate and electricity production with artificial wastewater and slaughter wastewater. The cost effectiveness of anode materials was also evaluated. The results showed that anode materials had no obvious effect on the start-up of MFC. All MFCs finished their started-up on day 24. Using artificial wastewater[acetate 1 g·L-1 in 50 mmol·L-1 phosphate buffer (PBS)] as substrate, the maximum power densities for the CB, CC and GF-MFCs were (56.3±1.8) W·m-3, (46.0±1.7) W·m-3, and (40.8±1.5) W·m-3, while with slaughter wastewater MFCs could produce (19.5±0.8) W·m-3, (16.9±0.6) W·m-3, and (11.9±0.5) W·m-3, respectively. COD removals of all the MFCs were approximately 90% with both artificial wastewater and slaughter wastewater. The CB-MFCs had a cost of (3.44±0.08) mW·yuan-1 with the artificial wastewater and (0.97±0.05) mW·yuan-1 with slaughter wastewater, which were 18.6%, 12.8% higher than that of CC-MFCs and 38.7%, 80% higher than that of GF-MFCs, respectively. These results demonstrate that carbon brush is the most suitable material used in large-scale MFC.

Optimizing electron spin resonance detection of hydroxyl radical in water.

The parameters affecting the electron spin resonance (ESR) detection of hydroxyl free radical in water are studied and optimized. The hydroxyl radical is generated by the Fenton reaction with iron (II) ammonium sulfate and hydrogen peroxide reacting in a phosphate buffer using N-tert-butyl-alpha-phenylnitron as the spin trap. The concentrations of Fe(2+), H(2)O(2), and phosphate buffer are the parameters studied. The Taguchi method and the orthogonal experiment design were used to evaluate the effects of these parameters on the ESR signal intensity. By the analysis of the signal-to-noise ratio and the analysis of variance, the order of importance of the various parameters on the hydroxyl radical formation is determined for optimal ESR detection of hydroxyl radical. The results will help the development of water purification technologies using hydroxyl free radical as a green oxidant.

Increasing efficiencies of microbial fuel cells for collaborative treatment of copper and organic wastewater by designing reactor and selecting operating parameters.

Organic matters and copper ions can be collaboratively removed from wastewater using a microbial fuel cell (MFC). High collaborative efficiencies for both organic matter and copper ions removal have not been achieved yet in previous studies. We demonstrate here that high collaborative efficiencies can be achieved by designing reactor construction and selecting operational parameters based on the results of linear sweep voltammetry (LSV). When the MFC was constructed as 1:2 volume ratio of anode to cathode chamber and operated at optimal conditions, 83% COD removal and 87% copper ion removal were obtained at the same time. In addition, the Cu-MFC also performed a high coulombic efficiency (CE) of 89% for organic treatment, a cathodic efficiency of 80% for copper ion removal, and a maximum power density of 2.0 W/m(2).