Genetic population structure of Hawksbill turtle [Eretmochelys imbricta] using microsatellite analysis

Information on the genetic structure of marine species is essential for stock improvement programs. In order to analyses the genetic diversity of the Hawksbill turtle [Eretmochelys imbricte] by the microsatellite genetic method, 64 samples were caught from the beaches located in Kish and Qeshm islands. Polymerase chain reactions [PCR] of genomic DNA extracted from the samples were carried out using 5 pairs of microsatellite primers. The results of this study indicated that all 5 pairs of primers were polymorphic. Average numbers of real allele and effective allele were 4.90 and 2.99, respectively. Average rate of observed heterozygosity was 0.570 and that for expected heterozygosity was 0.616. Study of the Hardy-Weinberg equilibrium was shown the entire locus had not equilibrium except Cm3 and Ei8 locus in Kish area. Fst [0.166] and Rst [0.634] calculated by the Analysis of Molecular Variance [AMOVA] test illustrated that there are separate populations of Hawksbill turtle in this part of the Persian Gulf [Kish and Qeshm islands]. It seems that Kish's turtles live under better conditions in contrast to their Qeshm counterparts. Diminution of genetic variation within examined population decreases its adaptation to environmental alterations. We identified two different E. imbricte populations from north of the Persian Gulf

[Serratia marcescens B4A chitinase product optimization using Taguchi approach]

Chitinase production by newly isolated Serratia marcescens B4A was optimized following Taguchi's array methods. Twenty-three bacterial isolates were screened from shrimp culture ponds in the South of Iran. A chitinase-producing bacterium was isolated based on it's ability to utilize chitin as the sole carbon source. The isolate designated as B4A, was identified as Serratia marcescens based on its 16S rRNA sequence and key morphological, physiological and biochemical characteristics. The cultivation of Serratia marcescens B4A in the appropriate liquid medium resulted in production of high levels of chitinase. The malt extract and colloidal chitin represented the best nitrogen and carbon sources, respectively. Chitinase production by Serratia marcescens B4A was optimized following the Taguchi orthogonal array [OA] for the design of experiments [DOE]. Statistical experimental design via the Taguchi method was applied to determine the optimal levels of physical parameters and key media components in the medium, such as temperature, pH, NaCl and chitin concentrations. The results of this study showed that temperature of 30§C, pH 7.9, NaCl 0.1% [w/v] and chitin 1% [w/v] are optimal conditions for this protocol

Detection of plasmids in heavy metal resistance bacteria isolated from the Persian Gulf and enclosed industrial areas

Several heavy metal resistant bacterial strains were isolated from sediment and water samples collected from the Persian Gulf and enclosed industrial areas. All the isolated bacteria were identified by 16S rRNA gene sequencing. Isolated bacteria were tested for the presence of plasmids using the modified alkaline lysate method. The method was effective for identification and characterization of plasmids of different sizes without the use of highly toxic chemicals. The study revealed that the frequency of the occurrence of plasmids in heavy metal resistant bacteria was more than that in the common bacteria. The study also demonstrated that about 66% of isolated bacteria carried large [38-62kb] and/or small sized [4 >/= 2 kb] plasmids. The highest plasmid incidence [84.6%] was detected from industrial wastewater bacteria. A slightly higher incidence of plasmids occurred in bacteria isolated from marine sediments [55.5%] compared to that of the marine water [53.8%]. The findings suggested that plasmids are highly ubiquitous and predominant in most heavy metal resistant bacteria. Removal of lead and cadmium from solution by some of these bacteria was very efficient, approximately 120 mg/g dry weight-as high as 90%. The isolates tested, presented distinct uptake capacities and the best results were obtained for Delftia tsuruhatensis and Pseudomonas AU3411 respectively