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Alpha-amylases are the most important amylases used in industry. Among them, thermophilic alpha-amylases are of particular importance, which is due to their activity and stability in high temperatures. These enzymes produced by thermophile micro-organisms including bacteria. These thermophilic alpha-amylases are used in various industries such as processing of starch as well as production of detergents and biofuels. In this research, the bacteria which produce the thermophilic alpha-amylases were isolated and characterized in hot springs of Gorooh village in Kerman province. According to the results of screening on the specific liquid and solid media, AT59 was selected as the best strain. Morphological and biochemical characterization of the isolated strain indicated that it belonged to Bacillus sp. and was gram-positive, catalase positive, casein hydrolyzing and acid producing from lactose and sucrose. The results obtained from the optimization of the enzyme production medium showed that among the carbon, nitrogen and ion sources investigated, starch (1 gr/l), gelatin (2 g/l) and magnesium sulfate (1 g/l) had the most increasing effect on the production of AT59 alpha-amylase. Moreover, the highest enzyme production was obtained at pH 5. This enzyme also demonstrated the highest degree of activity and stability in 80 and 70 ℃, respectively. These findings suggested that this enzyme has a considerable potential for use in starch industry.
 

 
 

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Sex steroid hormones play important roles in many physiological processes, particularly in the reproduction of teleostei. Therefore, study of steroid hormones in fish is one of the important indicators of reproductive biology. In the present research, serum steroid hormones such as testosterone (T), 17β-estradiol (E2) and progesterone (P) in Esox lucius brood stocks, during one year, from autumn 2010 to summer 2011, in five periods (autumn, first half of winter, second half of winter, spring and summer) with three longitudinal classes: 300-360, 360-420 and 420-480 millimeters were studied. The results showed significant difference between levels of steroid hormones in three longitudinal classes and showed an increasing trend by increased length (P<0.05). In addition, there was significant different between levels of gonadal steroid hormones and different seasons (P<0.05). The highest level of 17-β estradiol was observed in autumn season. In the case of testosterone and progesterone hormones, higher levels were recorded in first and second half of winter, respectively.
 

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Nerve growth factor (NGF) is a neurotrophic factor that is functional in the survival, maintenance and differentiation of nervous system cells. This protein has three subunits, of which the beta subunit has the main activity. Its structure consists of a cysteine knot motif made up of beta strands linked by disulfide bonds. It can be used as a therapeutic agent in the treatment of many diseases. As NGF extracted from natural sources is unsuitable for therapeutic goals, many studies have attempted to produce recombinant β-NGF. In this study, Trigger Factor (TF) chaperone was expressed simultaneously with β-NGF in E. coli in order to obtain increased yield of soluble recombinant human β-NGF.  For this purpose, pET39b (+)::β-NGF and chaperone plasmid pTf16 were transferred to E.coli (DE3 strain). After the induction of each promoter, the total proteins and periplasmic proteins were extracted. To confirm the effects of TF on total protein and soluble β-NGF expression level, Bradford and Dot blot techniques and ImageJ software were used. Then, β-NGF was purified using affinity chromatography column (Ni⁺²-NTA). Also, the PC12 cells were treated with the protein for one week in order to study the function of purified NGF. Our data indicated that co-expression of TF could increase the soluble and periplasmic production of β-NGF but not total proteins. Also, the treatment of PC12 cell line with purified β-NGF, co-expressed with TF chaperone, showed differentiation of these cells to nerve cells. This indicated that the purified NGF is fully functional. Our data suggest that the co-expression of cytoplasmic chaperone (TF) with recombinant nerve growth factor might be an efficient approach to produce a proper quantity of soluble and active rhNGF.

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Lipase is used in the production of foods, flavor enhancers, detergents, cosmetics and pharmaceuticals. A common impediment to the production of commercial enzymes is their low-stability aqueous solutions. In this study, the downstream process was investigated to obtain a stable spray-dried lipase powder of Yarrowia lipolytica. The enzyme solution samples were supplemented with different concentrations of Arabic gum and milk powder to spray-drying. Samples were dried in a pilot spray dryer at inlet and outlet temperatures of 175 and 85 °C, respectively, at a flow rate of 15 liters per hour. The best lipase powder obtained from spray-drying with 3% of Arabic gum and 9% of milk powder formulation as compared with other formulations. Results showed that spray-dried lipase powders of Y. lipolytica had a good yield suitable for various applications.
 
 

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In order to investigate the differences in the shape of the big-head and two morphotypes of Phytophagous fish by geometric morphometric technique, 30 samples of each group, with a mean standard length of 25 ± 3 cm, were prepared. After fish were anesthetized by 1% Clove powder extract and stabilized in formalin buffer 4%, 6-megapixel digital images of the left profile of the specimens were prepared. A total of 17 morphological landmarks were digitized by tpsDig2 software and the tps files were prepared. All non-shaped data were removed from landmark coordinates by generalized procrustes analysis. After the approval of regression between shape space and tangent space, data were analyzed using Principal Component (PCA), Canonical Variation (CVA) and Cluster Analyzes (CA) methods in PAST and TPS series. According to the results, the head length and height, the size of dorsal fin, the length of pre ventral distance, the height of caudal peduncle and the degree of posterior position of the pectoral fin in bighead carp, are some of the distinctive morphological features among species, mainly related to their ecological niche (specially feeding strategies). In the case of silver carp variants, the posterior position of pectoral fin base in silver carp-R that is close to bighead carp, may be due to hybridization between bighead carp and silver carps.