Physiological study for extracted surface layer from Aeromonas hydrophila isolated from diarrhea

Abstract

A total of 349 stool samples were collected from the patients with diarrhea during the period from December 2014 to May 2015,the results show that there were 11(3.15%) positive isolates of Aeromonas hydrophila, these isolates were identified by cultural method ,biochemical tests and confirmed by API 20E and Vitek 2 system.Tryptose soy agar that contained Congo red stain was used to detect A.hydrophila isolates that produced surface layer protein (S-layer) ,eight (8) isolates was given positive result on this media. The S-layer protein was extracted by two methods, Sodium Dodecyl Sulphate (SDS 0.05%) solution was given significantly higher protein concentration in compared with LiCl 5M solution. Then it was precipitated by two methods also, ammonium per sulfate 80% was given significantly higher protein concentration in compared with acetone Con.95%. The molecular weight of S-layer protein was determined by SDS-PAGE and the result reveal that it was 52 KDa. The physiological factors that affecting on the production of S-layer protein from A.hydrophila was investigated by incubate the inoculated production media at different degree of temperature, pH, incubation period ,at the ordinary and shacking incubator, and by add (Glycine, Tyrosine ,Lysine ,Alanine) in two Con. 0.5mg/L and 1mg/L. The result show that all these factor affecting on the production of S-layer protein and the highest protein concentration was obtained at temperature 37 oc, pH 7, after incubation period 24 hrs., at shacking incubator, by add1mg/L of glycine.