Objective: The P19 murine embryonal carcinoma (EC) cell line is a valuable in vitro model cell that can be differentiated into neurons by cellular aggregation in presence of the differentiating agent retinoic acid (RA).Materials and Methods: Total RNA from P19 cells was extracted and cDNA was synthesized. Using specific primers, respective cDNAs were amplified and were analyzed by semi-quantitative RT-PCR.Results: In this project, a peroxisomal gene such as CATALASE has been selected and the profile of its expression has been investigated in P19 cells. Expression of peroxisomal gene like CATALASE, as peroxisomal matrix protein in comparison with pluripotency markers such as Oct4 and Nanog, neural markers such as Pax6, Ngn-1, Map2 and a house keeping gene such as b-tubulin have been investigated by RT-PCR.Conclusion: Data indicated that during neural differentiation, expression of pluripotency markers have been down regulated while, expression of neural markers was significantly increased. However incase of CATALASE gene expression, there was an increase in CATALASE gene expression upon Retinoic acid treatment, during neural differentiation, which was observed at the final steps of neurogenesis.

CATALASE is the one of the most important antioxidant enzymes that is found abundantly in liver and kidney. The alteration in activity and function this latter enzyme are widely investigated in various types of cancer to understand the cancer mechanism and its treatment. The changes in the CATALASE activity levels in a variety of cancer cells is as a specific property of tumor tissues due to the reducting CATALASE activity at mRNA level. In this review, various reports that examined the alterations in CATALASE activity and resistance to chemotherapy and its complications in the literature are summarized and discussed. Due to the important role of hydrogen peroxide in various stages of cancer process, CATALASE alters this process by detoxification of hydrogen peroxide. Chemotherapy increase free radicals to destroy the tumor cells, then, CATALASE activity reduced their impact on cancer cells. On the other hand, it might be concluded that production of drug resistance in chemotherapy is resulted due to increasing CATALASE activity. Therefor it seems CATALASE has contradictory influence on the treatment and development of cancer.

Background and Objectives: CATALASEs are a good scavenger of H O which degrades hydrogen peroxide into water and 2 2 oxygen. They are considered as a virulence factor that are present in both spores and hypha of fungi. There is limited data regarding CATALASE activity in Aspergillus species. This study aimed to assess the mycelial CATALASE activity of clinical and environmental isolates of Aspergillus niger, A. tubingensis, A. flavus, A. luchuensis, A. piperis and A. terreus. Materials and Methods: Briefly, clinical and environmental Aspergillus species were used in the current study. CATALASE ac-tivity was assessed for both groups of isolates including 13 A. flavus (12 clinical, 1 environmental), 13 A. terreus (8 clinical, 5 environmental), 26 A. tubingensis (13 clinical, 13 environmental), and 44 A. niger (25 environmental, 19 clinical) species. Fungal balls of mycelia were separated from the liquid culture and were crushed using homogenizer. The supernatants were collected and used for a CATALASE activity assay. Results: Totally, in our study 98 Aspergillus including 45 environmental and 53 clinical isolates were assessed for CATALASE activity. High CATALASE activity was detected among environmental Aspergillus species (Mean= 1. 62 mU/ml) and the mean of mycelial CATALASE activity among clinical A. terreus isolates was higher than environmental strains. Conclusion: In summary, mycelial CATALASE activity varied among species and environmental isolates demonstrated higher CATALASE activity. Totally a significant difference was found between clinical and environmental Aspergillus isolates.

We report a CATALASE-negative Staphylococcus aureus isolated from a 56-year-old male diabetic patient with foot ulcer who attended our surgery ward. Species identification was confirmed by Gram staining, standard biochemical tests and PCR amplification of the nuc and fem genes. Antibiotic susceptibility showed that the strain was sensitive to imepenem, chloramphenicol, amoxicillin, vancomycin and resistant to oxacillin, penicillin, ceftriaxone, erythromycin, clindamycin, and amikacin. Clinicians and microbiologists must be encouraged to identify and report these atypical strains and the infections associated with them in order to establish their role in pathogenesis.

Background: CATALASE enzyme plays an important role in the anti-oxidation defense of body so it is important to measure its activity. Nowadays CATALASE activity measurement is performed by expensive imported kits in various scientific fields. The purpose of this study was to design a sensitive fluorimetry method for measuring CATALASE activity with improved sensitivity, accuracy and speed.Materials and Methods: In this study, the reaction of hydrogen peroxide with peroxidase (as a reaction accelerator) was used in fluorimetry for CATALASE activity measuring in serum samples in order to increase the sensitivity of the assay. The sensitivity and intra- and inter-assay accuracy, verification test, recovery and parallelism tests, comparison method and correlation and coherence investigation methods were also performed. In order to increase the accuracy and speed of reading, the assay was performed in microplates and reading was done in fluorimetry plates.Results: The percentage of intra- and inter-assay variation coefficients were measured 3.8-6.6 % and 4.1-7.3%, respectively. Comparison of the results of mentioned method for 50 serum samples with common colorimetric method showed a good correlation (0.917). In assessing the accuracy, the recovery percent was obtained 91% to 107%. The test sensitivity was measured 0.02 IU/ml.Conclusion: The fluorimetry method by microplate reading has a sufficient precision, accuracy and efficiency for CATALASE activity measuring as well as speed of measurement.Thus it can be an alternative method to conventional imported colorimetric methods.