Isolation of moderately halophilic pseudoalteromonas producing extracellular hydrolytic enzymes from persian gulf.

Extracellular hydrolytic enzymes such as amylases, proteases, lipases and DNases have quite diverse potential usages in different areas such as food industry, biomedical sciences and chemical industries, also it would be of great importance to have available enzymes showing optimal activities at different values of salt concentrations and temperature. Halophiles are the most likely source of such enzymes, because not only their enzymes are salt-tolerant, but many are also thermotolerant. The purpose of this study was isolation of hydrolytic extracellular enzyme producing halophilic bacteria from water and sediment of the Persian Gulf. Isolated bacteria from water and sediment were inoculated in media with concentration of 0-20% NaCl to determine the optimum salt concentration for growth, isolates were also inoculated in 4 types of solid medium containing substrates of 3 extracellular hydrolytic enzymes including amylase, Protease and Lipase, to determine the quantitative detection of enzyme production, selected strains after more accurate physiological and biochemical studies were identified regarding phylogeny and molecular characteristics using 16S rRNA technique. Isolated enzyme producing bacteria belong to Pseudoalteromonas genera.

mtDNA variation of the critically endangered hawksbill turtle (Eretmochelys imbricata) nesting on Iranian islands of the Persian Gulf.

Genetic diversity of sea turtles (hawksbill turtle) was studied using sequencing of mitochondrial DNA (mtDNA, D-loop region). Thirty dead embryos were collected from the Kish and Qeshm Islands in the Persian Gulf. Analysis of sequence variation over 890 bp of the mtDNA control region revealed five haplotypes among 30 individuals. This is the first time that Iranian haplotypes have been recorded. Nucleotide and haplotype diversity was 0.77 and 0.001 for Qeshm Island and 0.64 and 0.002 for Kish Island, respectively. Total haplotype diversity was calculated as 0.69, which demonstrates low genetic diversity in this area. The data also indicated very high rates of migration between the populations of these two islands. A comparison of our data with data from previous studies downloaded from a gene bank showed that turtles of the Persian Gulf migrated from the Pacific and the Sea of Oman into this area. On the other hand, evidence of migration from populations to the West was not found.

Evaluation of metallothionein expression as a biomarker of mercury exposure in Scatophagus argus.

The effect of mercury exposure to total Metallothionein (MT) response and bioaccumulation under control and acute mercury exposure were investigated in scats (Scatophagus argus). Scats were exposed to different mercury concentrations (10, 20 and 30 microg Hg L(-1)) for 24, 48 and 72 h. Total MT levels were determined by Enzyme-Linked Immunosorbent Assay (ELISA) method. Mercury contents were determined through cold Vapour atomic Absorption spectrometry. Induction of MT during exposure was tissue specific, displaying different response pattern in gill and liver. Mercury accumulated much stronger in liver than gill and the latter also showed lower MT level. MT biosynthesis in liver showed a significant increase after exposure to different mercury concentration during different times. This increase was significantly correlated with mercury bioaccumulation. In contrast, presence of different mercury concentration during different times did not significantly modify total MT except for 72 h exposure at 30 microg L(-1) in gills. The results suggest that this form of MT existing in S. argus was Hg-inducible and could be extended the as a biomarker of mercury pollution in ecosystems.