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Showing 2 results for H. Sajedi
Salim Alhafyan, Zeynab Rezaei, S.s. Shahangian, Reza H. Sajedi,
Volume 14, Issue 2 (5-2023)
Abstract
Angiogenesis is involved in many physiological and pathological processes, including tumor growth, and VEGF is considered as the most important factor in this process. Nowadays, the production of single-domain antibodies (VHH) with the characteristic of inhibiting growth factors in cancer tumors is one of the new strategies for cancer treatment. In the previous research, it was found that camel VHHs isolated from phage display against VEGF play an essential role in inhibiting it. Here, the VHH that had the highest affinity for the VEGF was selected. Ice nucleation protein (INP) was used as anchoring motif for surface expression of E. coli, owing to the efficiency of its N terminal domain, this system is used to express the VHH. Accordingly, a construct harboring the first 537 nucleotide of InaK gene and nucleotide fragments of TEV protease recognition site and VEvhh10 was designed to express this protein in the surface display of E. coli cells. The results showed that the INP anchor is a suitable candidate for promoting the surface expression of VEvhh10 in E. coli. After expression of VEvhh10, isolation and purification were performed using centrifugation and washing, and its binding to VEGF was investigated. The results showed that VEvhh10 successful bind to VEGF and it can be used for therapeutic applications and clinical diagnosis of patients in the future.
Volume 16, Issue 2 (3-2014)
Abstract
The toxicity of chlorpyrifos to three Iranian populations of two-spotted spider mite, collected from Isfahan (ISR), Yazd (Yz) and Guilan (GUS2) Provinces were surveyed using the residual contact vial bioassay. The bioassay results showed that resistance ratios of ISR and Yz populations were 176.90 and 9.78 fold compared to the GUS2 population, respectively. Determination of esterase and glutathione-S-transferase activity and their kinetic parameters showed that ISR population had the highest specific activity and specificity constant among the studied populations. Besides, the content of mixed function oxidases in ISR population was the highest. However, synergistic effects of Piperonyl Butoxide, Diethyl Maleate and Triphenyl Phosphate showed that metabolic enzymes did not play an important role in resistance to chlorpyrifos in ISR and Yz populations and enhanced activity of esterase, glutathione-S-transferase and content of mixed function oxidases in these populations were probably due to resistance to some other acaricides. To determine the role of acetylcholinesterase insensitivity in resistance mechanisms, kinetic parameters and inhibitory effect of chlorpyrifos-oxon on this enzyme were investigated. The Km value of acetylcholinesterase was determined as 0.036, 0.04, and 0.050 mM using acetylthiocholine iodide for GUS2, Yz, and ISR populations, respectively. In addition, the insensitivity ratios of chlorpyrifos-oxon on acetylcholinesterase activity were estimated at 23.30 and 2.96 for ISR and Yz populations, respectively. These results confirmed amino acid substitutions in active site of this enzyme and also indicated that resistant population possed qualitatively altered AChE.
