m.r. kalbassi

Antibacterial activity of silver-impregnated vermiculite and silver removal capability of acid-treated vermiculite (Verm-A) were assessed through 4-stage water filtration systems. The antibacterial vermiculite was prepared through cation exchange process in silver nitrate solutions of 0, 500, 1000, and 2000 mgl-1 , named Verm-B0, Verm-B500, Verm-B1000, and Verm-B2000, respectively. The Verm-A was only treated with 1 M HCl to increase its negative zeta potential. Bacterium Aeromonas hydrophila was inoculated into the filtration systems and then total colony forming units in water samples was enumerated for 96 h. Flame atomic absorption spectrometer showed the maximum silver adsorption (49.17 mg/g) by Verm-B2000. Scanning electron microscopy micrographs illustrated silver with nano dimension crystallites with the average sizes of 274.808, 194, 162.258 nm on the surface of Verm-B2000, Verm-B500, and Verm-B1000, respectively. All the Verm-B products were approved to possess a strong antibacterial activity, with reducing the bacterial growth over 95% in all of the filtration systems containing Verm-B500-2000. The highest log reduction value of 3.47 CFU mL-1 at 96 h was observed for the filtration system containing Verm-B1000. The percentage of silver released from the total Ag in Verm-B500 was 32.36%, Verm-B1000 27.87%, and VermB2000 17.24%; of these amounts, 90.9%, 81.8%, and 75.7% were reabsorbed respectively, by Verm-A. The observed bactericidal efficiency could open an avenue to use silver-impregnated vermiculite in water treatment. Moreover, acid treated vermiculite could be introduced as an affordable absorbent for removal of silver from water filtration system, industrial wastewater and reduce metallic environmental contaminant

The present study demonstrated the effects of nonylphenol (xenoestrogen) on Persian sturgeon (Acipenser persicus) vitellogenin (VTG) protein changes and production. Identification, purification and changes of vitellogenin protein in sera of fish treated by 17-beta estradiol and different concentration of nonylphenol, were performed. Gel filtration of this protein demonstrated the actual size of vitelogenin is 420KD in the native form, but vitellogenin in denaturated polyacrylamide gel had the form of dimmer protein. Purified cleavage vitelloginin (lipovitelin), which obtained from protein of Persian sturgeon oocyte, injected to rabbit for polyclonal antibody production and polyclonal antibody tested with treated sera for vitellogenin production as a biomarker of xenoestrogen using Wester blotting and ELISA method. All groups treated with 10 and 100mg/kg concentration of nonylphenol had significant effect on VTG protein production (p< 0. 05) but the group received the lowest dose of nonylphenol (1mg/kg) showed no significant change in VTG protein production. These results further support the negative effect of xenoestrogen on Persian sturgeon, indicating that this index can be used as a biomarker of xenoestrogen in aquatic ecosystems.

In order to reduce the adverse effects of sexual maturation on growth and survival of rainbow trout, production possibility of all-female triploid was investigated by means of early heat shock on eggs fertilized by masculinized male’s sperm. Fish ploidy level was determined by erythrocyte size measurement and confirmed by gill nucleolus (NORs) counting as well as chromosome number. Sexual ratios and gonad development were determined by histological studies. Final results showed that progenies produced by mating sex-reversed (masculinized) males and normal females were totally female (100 %). Also, applying early heat shocks (26.5° C lasting 20 min, 20 min after egg fertilization) induced about 80 % triploidy in fishes. All-female triploid, all-female diploid and mixed-sex diploid fishes did not show any significant difference in incubation stages (eyed-stage egg rate, hatching, survival from hatching to active feeding), (P>0.05). Eyed-stage eggs rate, and hatching rate of eyed eggs in mixed-sex triploids were significantly lower than in other treatments (P<0.05). Testes development in diploid males was similar to that of triploid and was in early stages of spermatogenesis in 8 month old fish. Also, diploid ovaries were packed with oocytes at previtellogenic or perinucleolus stages. Although they showed distinct lamellar structure of an ovary, triploid ovaries contained no oocytes