Evaluation of immune response to recombinant Bacillus anthracis LFD1-PA4 chimeric protein.

BACKGROUND: Anthrax is a particularly dangerous infectious disease that affects humans and livestock. Efficacious vaccines that can rapidly induce a long-term immune response are required to prevent anthrax infection in humans. Domains 4 and 1 of the protective antigen (PA) and lethal factor (LF), respectively, have very high antigenic properties. AIMS: In this experimental study, the pET28a-lfD1-pa4 expression vector was designed, constructed and transferred into E. coli BL21 (DE3) plysS. METHODS: For this purpose, pa4 gene was amplified by polymerase chain reaction (PCR) and cloned in a pGEM T-easy vector. The pGEM-pa4 and pGEM-lfD1 were digested by XbaI and HindIII enzymes. The ligation reaction was performed by ligase T4 enzyme and the gene cassette, lfD1-pa4, was subcloned in pET28a and transferred to E. coli BL21 (DE3) PlysS. Expression and purification of chimeric proteins were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting techniques. The chimera LFD1-PA4 and mixed LFD1+PA4 proteins were injected four times into mice and antibody production was relativity evaluated by enzyme-linked immunosorbent assay (ELISA) test. RESULTS: The results showed that both chimeric and mixed proteins are immunogenic, but LFD1-PA4 has a higher potential to stimulate mice immune system. CONCLUSION: LFD1-PA4 chimeric protein induced a higher immune response than LFD1+PA4 mixed protein and elicited antibody responses to LF and edema factor (EF), therefore, it holds promise to be a more effective trivalent vaccine candidate to use in anthrax prevention.

Water quality trend analysis for the Karoon River in Iran.

The Karoon River basin, with a basin area of 67,000 km(2), is located in the southern part of Iran. Monthly measurements of the discharge and the water quality variables have been monitored at the Gatvand and Khorramshahr stations of the Karoon River on a monthly basis for the period 1967-2005 and 1969-2005 for Gatvand and Khorramshahr stations, respectively. In this paper the time series of monthly values of water quality parameters and the discharge were analyzed using statistical methods and the existence of trends and the evaluation of the best fitted models were performed. The Kolmogorov-Smirnov test was used to select the theoretical distribution which best fitted the data. Simple regression was used to examine the concentration-time relationships. The concentration-time relationships showed better correlation in Khorramshahr station than that of Gatvand station. The exponential model expresses better concentration - time relationships in Khorramshahr station, but in Gatvand station the logarithmic model is more fitted. The correlation coefficients are positive for all of the variables in Khorramshahr station also in Gatvand station all of the variables are positive except magnesium (Mg2+), bicarbonates (HCO3-) and temporary hardness which shows a decreasing relationship. The logarithmic and the exponential models describe better the concentration-time relationships for two stations.