Strongyloidiasis is a public health concern in northern regions of Iran, caused by Strongyloides stercoralis. Auto-infection cycle can be resulted in high parasitic load, especially in immunocompromised hosts. Because of low sensitivity of stool culture and stool-based microscopy techniques, detection of antibodies in patient's sera can be an alternative diagnostic technique for detection of the nematode. In the present study, as the first step of the development of an ELISA kit for the detection of antibodies against the nematode, IgG4 immunoreactive protein (NIE) was expressed in Escherichia coli expression system, purified and verified.The NIE gene sequence was retrieved from the GenBank. This sequence was codon-optimized for the expression in E. coli BL21 (DE3). The sequence was inserted into the expression vector pET-30b (+). The recombinant vector was then transferred into competent E. coli BL21 (DE3). Transformed colonies were selected and verified by colony PCR. NIE gene expression was induced with IPTG induction. The protein production was evaluated by SDS-PAGE and verified using Western blotting.The codon-optimized NIE gene had required parameters for expression in E. coli. NIE protein was proved and verified by SDS-PAGE and Western blotting.NIE recombinant protein was successfully expressed in E. coli expression system in appropriate amounts. The recombinant protein can be used for developing ELISA kit in diagnosis of S. stercoralis.
Background: Mycobacterium marinum is a ubiquitous, slow-growing nontuberclosis Mycobacterium (NTM), it can causes disseminated granulomatous infections in fish. Outbreaks in fisheries can be financially devastating and can also increase the chance of human exposure. Objectives: The aim of this work was evaluating the effects of some environmental stresses on M. marinum CCUG 20998. Methods: In this descriptive-analytic study M. marinum CCUG 20998 was subjected to different conditions of environmental stresses such as pH, oxidative, osmotic pressure, and temperatures. The effects of stresses were studied on growth, biofilm formation, and cell division and biochemical characteristics of M. marinum CCUG 20998.The growth data were analyzed by measuring colony forming unit (CFU) using SPSS software version 19. Results: The results showed that sodium chloride and hydrogen peroxide at %10 and 9600 ppm concentrations inhibit. Marinum CCUG 20998 growths, respectively. Tolerance to pH = 11 and temperature at 82.5°C was detectable. Also, environmental stresses could affects on some biochemical characteristics of M. marinum CCUG 20998. Biofilm formation reduced upon using all stress conditions. Conclusions: Bacteria are able to adapt to dramatically different environments, In the case of mycobacteria, there is direct correlation between stress and pathogenicity. The results obtained from this study provided useful information on survival and tolerance of M. marinum CCUG 20998 to different environmental conditions. Survival under stress conditions might not reflect the in vivo situation where host factors also contribute to establishment of the organism during infection.