The present study aimed to production of purified L-asparaginase from Vignaunguiculata. Different physiological parameters, such as pH, temperature and incubation period, were optimized for growth and maximum L-asparaginase production. The optimum parameters were 37°C, 30 min and pH 8.5. Maximum L-asparaginase was 886.4U/ml with a specific activity of 1140.7 U/ml (31 fold purification with 28 %yield) were obtained at optimum conditions. The purified L-asparaginase produced from Vignaunguiculata was used for characterization and general properties. The effect of pH and temperature on L-asparaginase activity as well as stability at different pH and temperature were determined. The optimum pH 8.5 and 37ºC temperature on L-asparaginase showed 100% residual activity. Stability of pH around 8.5 and temperature 70ºC showed 90 and 78 % residual activity at 30 and 60 min respectively. The Lasparaginase showed high stability at alkaline pH (pH 8.5) when incubated for up to 60h.The molecular weight of the produced L-asparaginase was close to 68.5 kDa. Cytotoxic activity of Lasparaginase was examined in vitro using four carcinoma cell lines. L-aspargenase has higher effective in growth inhibition against HEPG2 and HCT-116 but lower against HELLA and MCF7 carcinoma cell lines. The data show that L-aspargenase has a higher cytotoxic activity against HEPG2 and HCT116, revealed higher percentage of cell death, indicating antitumor properties, and demonstrate direct effect on cancer cell proliferation of HEPG2 and HCT116. Therefore, Vignaunguiculata was considered to be a suitable source for production of Lasparaginase has higher activity and good stability. Purified L-asparaginase obtained from Vignaunguiculata could be employed in drug chemotherapy and treatment of cancer.

No abstract

In order to induce colon cancer, the rats were given a weekly subcutaneous injection of 1,2-Dimethylhydrazine (DMH) at a dose of 20 mg/kg b.w. for five weeks. Afterwards, some of the rats ingested fish oil for either 4 weeks (DMH-FO4 group), or 17 weeks (DMH-FO17 group). The remaining rats continued without any supplementation for the same 4 weeks (DMH4 group), or 17 weeks (DMH17 group). Another two groups of rats did not receive the DMH and were given fish oil (FO17 group) or a normal diet only and considered as the control group (CN group). At the end of the experiment, the rats were sacrificed; and were subsequently subjected to biochemical and molecular biological analyses as well as histopathological examinations. The results showed increased levels of lactate dehydrogenase (LDH), malondialdehyde (MDA) and alkaline phoshatase (ALP) activities in the DMH rats compared to the control. The liver and colonic changes that were induced by DMH were significantly improved through fish oil supplementation in the DMH-FO17 group. The molecular analysis revealed that DMH treatment induced the expression alterations of genes p53, p27 and p21 and increased DNA band patterns related to cancer, while both FO17 and DMH-FO17 groups showed much better results. A histopathological examination of the DMH17 group revealed colon adenocarcinoma and several lesions in rat liver tissues. An improvement in the histopathological picture was seen in the livers and colons of groups DMH-FO17. In conclusion, the present results demonstrated the anti-carciongenic effect of herring fish oil against DMH induced colon carcinogenesis in rats. The inhibitory effect of FO was due to the modulation of elevated biochemical parameters, DNA damage, gene expression and histopathological lesions caused by DMH. KEY-WORDS: Colorectal cancer -DMH -Fish oil -Gene expression -Rats. INTRODUCTIONAmong the factors that contribute to the appearance of cancer, diet plays a fundamental role. Fats are the main component related to the increase in the incidence of cancerous diseases, particularly breast, prostate and colorectal cancer. Colon cancer is one of the leading causes of death in both men and women in Western countries (Parker et al., 1995;and Jemal et al., 2003) and it became the number six leading cause of cancer deaths in Egypt (WHO report, 2006). Several RESUMEN Efecto del aceite de pescado de la dieta en cáncer de colon inducido por dimetilhidrazina en ratas.Este estudio fue realizado para examinar la eficacia de la suplementación de aceite de pescado en la carcinogéne-sis de colon en ratas wistar machos. Para la inducción del cáncer de colon, las ratas fueron tratadas semanalmente con una inyección subcutánea de 1,2-dimethyl hydrazine (DMH) a una dosis de 20 mg/kg de peso durante cinco semana. A continuación, algunas ratas tomaron aceite de pescado durante 4 semanas, o durante 17 semanas (grupo DMH-FO17). Las ratas restantes continuaron sin ningún tipo de suplementación durante las mismas 4 semanas (grupo DMH4), o 17 semanas (grupo DMH17). Otros dos...

No abstract

Pichia pinus was found to be capable of growing on mango wastes, producing pectinase (pectin lyase, EC-4.2.2.10) and lactase (beta-galactosidase, EC-3.2.1.23) enzymes. The two enzymes were successively purified by precipitation with ammonium sulfate followed by chromatography on Sephadex G-120. The purification procedure provided 1,846 and 929 fold purification with 20.6 and 24% yield recovery of pectinase and lactase, respectively. the km value of pectinase was 0.33% for pectin at pH 4.5 and that for lactase was 0.166% for lactose at pH 7.0. The purified enzymes, pectinase and lactase are stable up to 50 degrees C for 60 and 45 min, respectively, with 20 and 35% loss of their activity. Gel filtration on Sephadex G-200 indicated that the molecular weights of the purified pectinase was 90 x 10(3) Dalton and of lactase 115 x 10(3) Dalton. On the basis of the evaluation tests done, the enzymes were considered to have a potential technological interest as treating mango pastes (residues left after mango juice preparation) with the two prepared enzymes resulted in an increase of the colour intensity, total carbohydrate content and juice yield. Treating milk with the purified lactase also showed an increase in the total carbohydrate and reducing sugar produced.