Introduction: Human T cell Lymphotropic l.irus type I is responsible for Adult T cell Leukemia/Lymphoma and HTLV-I associated myelopathy. The aim of this study was constructing two reporter plasmids to enable us to evaluate the effects of HTLV-I Tax protein upon intra cellular signalling pathways which recruit CREB and NFkB proteins. Material and Methods: A complete coding region of bacterial betagalactosidase gene was subcloned into pUC18 , followed by inserting a poly adenylation signal downstream to it. Promoter regions of HTLV-I long terminal repeat and Interlukin 2 receptor alpha (which were stimulated by CREB and NFkB respectively) were amplified by PCR and separately inserted upstream to betagalactosidase gene, leading to construction of two reporter plasmids. The effect of cotransfection of a Tax expressing plasmid with each of these plasmids was evaluated by X-gal staining, beta galactosidase ELlSA or beta galactosidase activity assay with CPRG substrate. Results: Results clearly showed that both reporter plasmids responded well to stimulation of their promoters by Tax and the produced beta galactosidase could successfully be detected by all three methods. Results of ELlSA and assay tests for betagalactosidase showed a high correlation (r=0.949). Conclusion: Both reporter plasmids constructed in this study are able to produce considerably more betagalactosidase after stimulation by HTLV-I Tax. Advantages and disadvantages of three evaluating method for detection of betagalactosidase are studied and discussed.

In this study, twenty-five whey samples collected from dairy industries in the city of Isfahan. The samples were cultured on malt extract broth (MEB) and yeast extract glucose chloramphenicol agar (YGCA) media. Eleven yeast strains (designated M1 to M11) were isolated from the culture. The strains were identified by their morphological and physiological properties. Betagalactosidase activity in the yeast strains showed that a strain of K. lactis designated as M2 had highest enzyme activity (up to 8103 EU/ml). The isolated yeast strains were examined for their ability in reduction of the biological oxygen demand (BOD). The results demonstrated a high level of reduction in the M2 strain. This strain was also found to have highest level of single cell protein (SCP), production (up to 11.79 g/l dry mass cell). The co-culture of the isolated yeast strains with Saccharomyces cerevisiae resulted in the highest biomass yield up to 22.38 g/l dry mass cell and significant reduction in initial BOD. Together, the data showed that the isolated yeast strain could be of valuable application in bioconversion of whey.

Crude Enzyme (beta-galactosidase) Extract (CEE) was produced by Lactobacillus ssp. bulgaricus CHR Hansen Lb-12 and was applied in sterile milk which had been processed through Ultra High Temperature method (UHT milk), for hydrolyzing lactose. Lactosehydrolyzed milk was also produced by a pure and commercially available betagalactosidase (Maxilact). Optimum quantities of CEE and Maxilact enzyme, for producing lactose-hydrolyzed milk, during 6 hours of processing, were 0.418 and 0.512 U ml-1, respectively. Using more than 0.418 U ml-1 CEE resulted in unacceptable acidity. Acidity of lactose-hydrolyzed milk produced through 0.418 U ml-1 of CEE was significantly increased from 15 to 17oD, while enhancement of acidity in lactosehydrolyzed milk produced through Maxilact enzyme was not significant. Total count of lactose-hydrolyzed milk by 0.418 U ml-1 CEE, after 6 hours of processing was significantly increased from 5 to 30 CFU (Colony Forming Unit). Sensory evaluation of lactosehydrolyzed milk and ordinary UHT milk (as control) did not show any significant differences with respect to acceptability of sweetness, taste, aftertaste and color.

Proper conditions for producing crude beta-galactosidase from waste materials were determined. This enzyme is to be used in the production of lactose-hydrolyzed milk. Whey permeate was used as a basic medium. Twenty seven treatments were developed by 3 varying factors of: yeast extract (1, 2, and 3%), wheat steep liquor (1, 2, and 3%), and whey powder (0.5, 1, and 1.5%). Crude enzyme extract was obtained by sonication of the cells collected from cultivation of Lactobacillus delbrueckii ssp. bulgaricus in various media at 43oC. The beta-galactosidase activity was assessed using Ortho-Nitro-Phenyl-beta-Dgalactopyranoside (ONPG). Yeast extract and whey powder had both significant effects (P<0.01), while wheat steep liquor proved to be ineffective. Yeast extract had the most pronounced effect on the production of beta-galactosidase. The effect of the interactions of yeast extract-whey powder and wheat steep liquor-whey powder were significant at 5% level (P<0.05), while the effect of the interaction of yeast extract-wheat steep liquor was significant at 1% level (P<0.01). Interaction effect of the 3 factors on the production of betagalactosidae was significant (P<0.01). The best combination for production of betagalactosidase (4.924 U ml-1) was 3% yeast extract, 1.5% whey powder and 2% wheat steep liquor.