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The potato tuber moth (PTM), Phthorimaea operculella (Zeller), is a major pest of potato, both in the field and storehouses. In this study, we have evaluated the lethal effects and persistence of Zingiber officinale (Roscoe) pure (PEO) and nano-formulated essential oil (NFO) on different developmental stages (egg, male and female adults) of PTM. Essential oil was extracted by hydro-distillation using a Clevenger-type apparatus. The essential oil was analyzed by gas chromatography/mass spectrometry (GC/MS). Nanofibers were produced by electrospinning technique. The morphology of nanofibers was investigated by SEM. Fourier transform infrared (FTIR) was used to identify the characteristic functional groups in the PEO, nanofiber and PEO/NFO scaffold. Bioassays were performed in 250 ml glass jars. The essential oil consisted of α-Zingiberene as the most abundant component (14.21%), followed by Ar-curcumene (12.58%), β-sesquiphellandrene (12.48%) and cis-α-bisabolene (10.29%). The results of FTIR spectra showed the establishment of the functional groups of PEO on the structure of the nanofiber. The images of SEM also demonstrated the establishment of PEO in the structure of the nanofiber. LC50 values of PEO and NFO were estimated 75.44 and 30.24µl/l air for eggs, 19.08 and 10.28µl/l air for female adults, and 17.76 and 9.56µl/l air for male adults, respectively. Persistence data showed that nano-formulated essential oil (49 days) in comparison with pure essential oil (15 day) had longer persistence. The results demonstrated that Z. officinale PEO and its nano-formulation could play an important role as natural pesticides for the management of PTM.

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Animal chymosin due to the high quality of cheese texture and flavor is the most effective enzyme for cheese production. Due to the increasing demand for this enzyme, in addition to the plant and microbial sources, recombinant sources should be considered for chymosin production. In this study, in order to produce recombinant chymosin, as well as improving the expression of bovine chymosin gene in yeast, the sequence of the chymosin A gene was optimized and synthesized based on the codon usage of the Pichia pastoris and was cloned in an appropriate expression vector. The codon adaptation index (CAI) increased from 0.59 to 0.72 after codon optimization. There were 41 yeast rare codons (with frequency of less than 10%) in the bovine chymosin A gene, whereas no rare codons in the codon optimized sequence. In order to transfer the resynthesized chymosin A gene to the yeast expression vector pPIC9, this gene was proliferated using the specific primers and was cloned in the PTG-19 vector. Recombinant (PTG19-chymA) colonies were selected by the screening of white-blue colonies method. The resynthesized chymosin A gene was then cut from PTG19-chymA vector using the restriction enzymes Not I and EcoR I, cloned into the pPIC9 vector and was transformed into DH5α strain of E. coli. Colonies containing recombinant vector (pPIC9-chymA) were identified and selected using colony-PCR technique. The recombinant nature and correct insertion of resynthesized chymosin A gene in the yeast expression vector pPIC9 were confirmed by plasmid extraction and its digestion with BamH I enzyme.