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Musa creek is one of the most important and valuable ecosystems in south-west of Iran. It is a suitable place for spawning of many fish species and other organisms meanwhile it has drawn attentions due to exist of various industries around this part of Persian Gulf. Previous studies confirm marine fishes have collected high amounts of pollutants in this area. In the present study, pathological alterations of liver is used as an indicator for evaluating of contaminants effects on two fish species including yellowfin seabream and abu mullet in Musa creek. In this regard, 50 yellowfin seabreams and 50 abu mullets were collected in 2010 from different sampling sites in Mussa creeks including Petrochemical, Jaafari, Majidieh oil pier, Ghazaleh and Zangi. The livers of fish were passed from routine histological process, and five-micrometer thick sections were stained in hematoxylin-eosin for examination by light microscopy. The commonest pathological changes in the liver of yellowfin seabreams and abu mullets were including vacuolation of hepatocytes, hemorragia, melanomacrophages aggregates, nuclear hypertrophy, focal necrosis and enlargement of sinusoid. Histopathological alteration index was determined on the basis of frequency of pathological changes in liver of two species. The most amount of HAI for liver of both species was observed at the Petrochemical station (p<0.05). It is probably due to extensive various petrochemical industries which surround this part of creek and a great deal of contaminants such as chemical and heavy metals daily discharged into it. The least amount of HAI in both species was related to Zangi station.

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The present study aimed to study the histological structure of body wall of sea cucumbers collected from the coasts of Persian Gulf in Hormozgan. In this regard, sampling was done from three regions in Hormozgan including Bandar Lengeh, Qeshm and Hormoz during 2010. 7 species including Holothuriaparva, Holothuriaaraenicola, Holothuriaatra, Holothuriahilla, Holothurialeucospilota, Thyonedura, Protankyrapseudodigita were indentified from the sampling sites. The histological structure of body wall was studied in all of collected species to evaluate the possible different among them. Firstly, all samples were anesthetized using magnesium chloride to prevent from visceral rejection and then fixed in 10% formalin. The samples were taken from body wall and then were processed through routine paraffin embedding technique, cut at 6 µm and stained with Hematoxylin and Eosin to study using light microscope. The results showed that the body wall consists of an epidermis, a dermal connective tissue layer, a layer of circular musculature and a mesothelium. Five pairs of longitudinal muscles are also observed in Holothuroids.

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Biosorption is an effective technology for optimal removal of pollutants such as heavy metals from marine ecosystems. In the present study, the microorganism, resisted to zinc, was isolated from Persian Gulf sediments and indentified via biochemical tests. Then, the growth ability of indentified microorganism was investigated in different concentrations of zinc. Also, the effect of salinity on the growth of microorganism was studied and the optimal conditions for its growth were determined. Pseudomonas sp. was isolated as a zinc-resistant bacterium and identified using biochemical tests and bacteriologic references. The mentioned bacterium was able to grow up to a high concentration of zinc (320 mg/l) and the increase in zinc concentration in environment caused the bacterium growth to decrease. The maximum bacterium growth in 20 mg/L of this metal was measured to be 0.87. With the increase in concentration of this metal to 320 mg/L in environment, the bacterium growth decreased to 0.4 which shows the significant difference with the maximum bacterium growth in 20 mg/L concentration of zinc metal (p≤0.05). The optimum temperature was 25 °C for this bacterium and its maximum growth was significantly different in 15 °C and 45 °C (P ≤ 0.05). The results of halophile test also showed that this bacterium is halotolerant. Bacterial growth increased by increasing salt concentration from 0 to 4%, but when salt concentration reaches to 6, 8 and 10%, it decreased significantly.