فهرست مطالب عطیه عطائی

Using efficient and environment-friendly techniques for the remediation of potentially toxic and harmful metals in contaminated soils plays a vital role in public health. The present study was conducted to assess the efficiency of the biosurfactant produced by the tolerant bacteria to cadmium (Cd) for the removal of Cd from contaminated soil as a completely randomized design with three replications.

Three native strains of bacteria including Bacillus pumilus, Alcanivorax dieselolei, Marinobacter hydrocarbonoclasticus were studied in terms of resistance to different levels of Cd contamination. In order to evaluate the production capacity of biosurfactants in the superior strain, 4 tests of emulsification measurement, oil spreading, drop collapsing, and hemolytic activity were used. Then, to investigate the amount of Cd removal from the contaminated soil, three treatments including the superior strain, the biosurfactant produced by it, and the control soil (i.e., without the strain and biosurfactant) were added to the contaminated soil.

By applying Marinobacter hydrocarbonoclasticus as the superior strain and the biosurfactant produced by it to the Cd contaminated soil, it was observed that the biosurfactant treatment significantly had more ability on Cd removal from the soil compared to other treatments. Also, there was no significant difference between the Marinobacter hydrocarbonoclasticus and the control treatment.

In general, it is concluded that after local calibration and also repeating and performing the experiment in natural conditions, the biosurfactant produced by Marinobacter hydrocarbonoclasticus can be more reliably used as a conditioner for the soils contaminated with Cd.

5 α-Reductase type 2 deficiency, caused by mutations in the SRD5A2 gene, leads to an autosomal recessive disorder of sex differentiation (DSD) in 46, XY persons.  A 2 years old female with ambiguous genitalia was referred to Genetic Foundation of Khorasan Razavi (GFKR), IRAN. Her secondary sex characteristics, level of sex hormones, the development of reproductive system and karyotype were assessed. Whole-exome sequencing (WES) was preformed to find the pathogenic genetic variations associated with ambiguous genitalia. Also, Sanger sequencing was used to verify the WES results in the patient. Segregation analysis was performed to confirm mutation in the parents and other relatives. Physical examination and ultrasonography data demonstrated that the patient have testis in the left labium majus and right groin but does not have a uterus or ovaries. Sex hormone examination revealed that hormone therapy was successful and the level of FSH, LH, testosterone, and dihydrotestostron (DHT) was 2.8 mlu/ml, 2.4 mlu/ml, 15ng/dl, 21pg/ml, respectively. Cytogenetic study showed 46XY compatible to normal male karyotype. According to WES result and Sanger sequencing a homozygote loss of function mutation (c.16C>T; p.Gln6Ter) in SRD5A2 has been detected. Segregation analysis confirmed the mutation in the family. Homozygote mutation in SRD5A2 is the main cause of disorders of sex development in this family.

In this research, the effect of chitin binding domain was investigated on the enhancement of chitinase activity Chit42 enzyme tested on the last instar larvae of Ephestia kuehniella Zell. Chimeric chitinase containing chitin binding domain from Trichoderma atroviride 18-10 chitinase and Chit42 were cloned in pET 26b(+) and over expressed in Escherichia coli. The expressed protein was observed and verified by SDS-PAGE method. Hydrolytic activity of the chimeric and native enzymes was measured on the dry powder of 10 last instar larvae of E. kuehniella. The effect of 3 different concentrations of each enzyme including 30, 45 and 60μg/ml was evaluated on the mortality of 30 E. kuehneilla last instar larvae (each 10 larvae as 1 replication) at 28ºC, 50% RH and 16:8h L:D. Larvae were treated by protein solution lacking enzymes in control. After 24h, the number of dead larvae was counted in treatments and control. Mortality was calculated by Abbott’s formula. The chimeric chitinase and native enzymes activity on the larval chitin (substrate) was calculated to be 15.47 and 9.16U/ml, respectively. Bioassay tests demonstrated that the chimeric chitinase and Chit42 enzymes imposed 65 and 47% mortality to E. kuehniella larvae, respectively. Finally, microscopic observation demonstrated higher amount of chitin degradation in treated larvae with chimeric chitinase compared with those treated by native Chit42.