This study examines histometrical changes induced by sodium arsenite (SA), as an environmental pollutant, and investigates the protective effect of α-tocopherol on ovaries of SA-treated rats during the prenatal stage until sexual maturity. Rats were classified into groups: control, SA (8 ppm/day), α-tocopherol (100 ppm/day), and SA+α-tocopherol. Treatment was performed from pregnancy until maturation when the rats and ovaries were weighed. The Cavalieri method was used to estimate volume of the ovaries, cortex, medulla, and corpus luteum. The mean diameter of oocytes, granulosa cells, and nuclei were measured and volume was estimated using the Nucleator method. The number of oocytes and thickness of the zona pellucida (ZP) were determined using an optical dissector and orthogonal intercept method, respectively. SA reduced the body and ovary weight, the number of secondary, antral and Graafian oocytes, volume of the ovaries, cortex, medulla and corpus luteum, mean diameter and volume of oocytes in primordial and primary follicles, mean diameter and volume of oocyte nuclei in all types of follicles, and mean thickness of the ZP in secondary and antral follicles. Also, the mean diameter and volume of granulosa cells and their nuclei in antral and Graafian follicles decreased significantly. Vacuolization and vascular congestion in the corpus luteum and an increase in the number of atretic oocytes were seen in the SA group. Most of these parameters were unchanged from the control level in the SA+α-tocopherol group. It was concluded that α-tocopherol supplementation reduced the toxic effects of SA exposure on ovarian tissue in rats.
The periplasmic proteome of recombinant E. coli cells expressing human interferon-α2b (INF-α2b) was analysed by 2D-gel electrophoresis to find the most altered proteins. Of some unique up- and down-regulated proteins in the proteome, ten were identified by MS. The majority of the proteins belonged to the ABC transporter protein family. Other affected proteins were ones involved in the regulation of transcription such as DNA-binding response regulator, stress-related proteins and ecotin. Thus, the production of INF-α2b acts as a stress on the cells and results in the induction of various transporters and stress related proteins.
This study was carried out to express human epidermal growth factor (hEGF) in Pichia pastoris GS115. For this aim, the hEGF gene was cloned into the pPIC9K expression vector, and then integrated into P. pastoris by electroporation. ELISA-based assay showed that the amount of hEGF secreted into the medium can be affected by the fermentation conditions especially by culture medium, pH and temperature. The best medium for the optimal hEGF production was BMMY buffered at a pH range of 6.0 and 7.0. The highest amount of hEGF with an average yield of 2.27μg/mL was obtained through an induction of the culture with 0.5% (v/v) methanol for 60h. The artificial neural network (ANN) analysis revealed that changes in both pH and temperature significantly affected the hEGF production with the pH change had slightly higher impact on hEGF production than variations in the temperature.