Risk estimation of heavy metals from consumption of silver pomfret and tiger tooth croaker in Hormozagan Province

In the present study, accumulation of manganese, cadmium, zinc, iron and copper in the commercially fish species (silver pomfret and tiger tooth croaker) caught from Bandarabbas coasts at 2010 was measured and the risk of daily intake of them in Hormozagan urban population was estimated. The average concentrations (µ/g dry weight) of manganese, cadmium, zinc, iron, and copper in the muscle tissue of silver pomfret were 1.248, 0.217, 14.444, 2.397 and 3.300, respectively, while the concentration of them in tiger tooth croaker were 1.009, 0.403, 12.564, 4.467 and 2.366, respectively. According to fish consumption rate, urban populations of the province were divided into four groups; low, medium, high and very high. The target hazard quotient (THQ) in each group calculated separately. The THQ of all groups were much lower than 1 in the two fish. The results showed that urban populations of the province have not any risk due to accumulation of the studied heavy metals

Determination of heavy metal (lead and cadmium) concentrations in liver and muscle tissue of Indian mackerel (Rastrelliiger kanagurta) in Persian Gulf

This study was conducted to compare heavy metal concentrations including lead and cadmium in liver and muscle tissues of Indian mackerel (Rastrelliiger Kanagurta) in Bandar Lengeh, Hormoz island, Hengam island and Kolahi regions. In current research, the influence of season, sex and size (length and weight) on Pb and Cd concentrations in Indian mackerel was investigated in these areas. Then Lead and cadmium concentrations in muscle tissues were compared with international standards for human consumption. Sampling was performed in summer and winter. Metal concentrations of organs were assessed by dry digestion method and atomic absorption spectrometer (AAS). Results showed that there are statistically significant differences between concentrations of lead and cadmium in liver and tissues of the fish in these regions (Bandar Lengeh, Hormoz, Hengam and Kolahi) (p0.05). In addition, there is no correlation between lead and cadmium concentrations in muscle and liver of Indian mackerel with size (length and weight) (p>0.05)

Fault & Fracture Development in Foreland Fold and Thrust Belts - Insight from the Lurestan Province, Zagros Mountains, Iran

Second Arabian Plate Geology Workshop Abu Dhabi, UAE, 24 - 27 January 2010The Simply Folded Belt of the Zagros Mountains, Iran, represents one of the best examples of foreland fold and thrust belt. A regional fault and fracture analysis of the Cenomanian ¿ Coniacian Ilam and Sarvak formations, exposed in southern Lurestan Province, is presented as a case study for fault and fracture development in folded belts. The area is characterised by the occurrence of gentle to tight anticlines and synclines whose NW-SE axial traces are parallel to the general trend of the belt. Fold style is intimately related to both vertical and lateral facies distribution. The two formations belong to the Bangestan Group and, in this area, they represent the oldest strata exposed in the core of most anticlines outcropping at surface. Distribution, kinematics and timing of faults and fractures have been characterised through extensive fieldwork and interpretation of orthorectified QuickBird imagery and 3-D virtual outcrop models based on LiDAR technology. Data have been collected from 10 anticlines covering an area of approximately 150 x 150 km. Key outcrops for fracture and fault kinematics interpretations are presented. Field observations and interpretation of QuickBird and 3-D photorealistic models suggest a complex fault and fracture geometry and timing relationship. Both fractures and faults record pre-folding to uplift-related deformations. Pre-folding structures are typically represented by small-scale, flat-ramp-flat geometry thrusts, systematic veins and stylolites, which are superimposed on inherited syn-sedimentary normal faults. Folding-related structures generally reactivated pre-existing fracture and fault planes. Strike-slip faulting is typically recorded as the last faulting event and is probably related to late stage of fold tightening. All structures are geometrically and kinematically consistent with the trend of the Arabian passive margin and its subsequent tectonic inversion. Uplift and stress release induced opening and propagation of through-going fractures. Faults and fracture orientations generally change accordingly with local fold trend. Symmetry between fracture and fold orientation, although commonly interpreted as evidence for folding-related fracture development, is here interpreted as evidence of syn- to post-folding local vertical axis passive rotation

Structure Analysis of a New Psychrophilic Marine Protease

A new psychrophilic marine protease was found from a marine bacterium Flavobacterium YS-80 in the Chinese Yellow Sea. The protease is about 49 kD with an isoelectric point about 4.5. It consists of 480 amino acids and is homologous to a psychrophilic alkaline protease (PAP) from an Antarctic Pseudomonas species. The protein was purified from the natural bacterium fermented and crystallized. Its crystal structure (PDB ID 3U1R) was solved at 2.0 Å by Molecular Replacement using a model based on PAP, and was refined to a crystallographic Rwork of 0.16 and an Rfree of 0.21. The marine protease consists of a two domain structure with an N-terminal domain including residues 37–264 and a C-terminal domain including residues 265–480. Similar to PAP, the N-terminal domain is responsible for proteolysis and the C-terminal is for stability. His186, His190, His196 and Tyr226 are ligands for the Zn2+ ion in the catalytic center. The enzyme's Tyr226 is closer to the Zn2+ ion than in PAP and it shows a stronger Zn2+―Tyr-OH bond. There are eight calcium ions in the marine protease molecule and they have significantly shorter bond distances to their ligands compared to their counterparts in all three crystal forms of PAP. On the other hand, the loops in the marine protease are more compact than in PAP. This makes the total structure stable and less flexible, resulting in higher thermo stability. These properties are consistent with the respective environments of the proteases. The structural analysis of this new marine protease provides new information for the study of psychrophilic proteases and is helpful for elucidating the structure-environment adaptation of these enzymes

Molecular Dynamics of Mesophilic-Like Mutants of a Cold-Adapted Enzyme: Insights into Distal Effects Induced by the Mutations

Networks and clusters of intramolecular interactions, as well as their “communication” across the three-dimensional architecture have a prominent role in determining protein stability and function. Special attention has been dedicated to their role in thermal adaptation. In the present contribution, seven previously experimentally characterized mutants of a cold-adapted α-amylase, featuring mesophilic-like behavior, have been investigated by multiple molecular dynamics simulations, essential dynamics and analyses of correlated motions and electrostatic interactions. Our data elucidate the molecular mechanisms underlying the ability of single and multiple mutations to globally modulate dynamic properties of the cold-adapted α-amylase, including both local and complex unpredictable distal effects. Our investigation also shows, in agreement with the experimental data, that the conversion of the cold-adapted enzyme in a warm-adapted variant cannot be completely achieved by the introduction of few mutations, also providing the rationale behind these effects. Moreover, pivotal residues, which are likely to mediate the effects induced by the mutations, have been identified from our analyses, as well as a group of suitable candidates for protein engineering. In fact, a subset of residues here identified (as an isoleucine, or networks of mesophilic-like salt bridges in the proximity of the catalytic site) should be considered, in experimental studies, to get a more efficient modification of the features of the cold-adapted enzyme

Cold-adapted RTX lipase from antarctic Pseudomonas sp. strain AMS8: isolation, molecular modeling and heterologous expression

A new strain of psychrophilic bacteria (designated strain AMS8) from Antarctic soil was screened for extracellular lipolytic activity and further analyzed using molecular approach. Analysis of 16S rDNA showed that strain AMS8 was similar to Pseudomonas sp. A lipase gene named lipAMS8 was successfully isolated from strain AMS8, cloned, sequenced and overexpressed in Escherichia coli. Sequence analysis revealed that lipAMS8 consist of 1,431 bp nucleotides that encoded a polypeptide consisting of 476 amino acids. It lacked an N-terminal signal peptide and contained a glycine- and aspartate-rich nonapeptide sequence at the C-terminus, which are known to be the characteristics of repeats-in-toxin bacterial lipases. Furthermore, the substrate binding site of lipAMS8 was identified as S207, D 255 and H313, based on homology modeling and multiple sequence alignment. Crude lipase exhibited maximum activity at 20 C and retained almost 50 % of its activity at 10 C. The molecular weight of lipAMS8 was estimated to be 50 kDa via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal expression level was attained using the recombinant plasmid pET32b/BL21(DE3) expressed at 15 C for 8 h, induced by 0.1 mM isopropyl β-D thiogalactoside (IPTG) at E. coli growth optimal density of 0.5