تولید و تخلیص آنتروتوکسین مقاوم به حرارت یرسینیا آنتروکلی تیکا

Since the heat-stable enterotoxin (ST) produced by yersinia enterocolitica is similar to enterotoxin production by E. coli, it is probably classified among toxinogenic bacteria. The culture filtrate of ST-producing strains of Y. enterocolitica is able to activate Guanylate cyclase and to increase fluid accumulation action of cylic Guanosin 3', 5' - monophosphate (cGMP) in sucking mouse intestine. For production of enterotoxin (ST), three strains of Y. enterocolitica (4052-6809-6810) were selected from the Institute Pasteur culture collection. All were serotype 3, biotype 4 and had been isolated from patients with diarrhea. After obtaining a suitable amount of enterotoxin (ST), the crude toxin was fractionated by various methods including: Ultrafiltration, gel filtration, high performance liquid chromatography (H.P.L.C) and isoelectric focusing. The results showed that the purified (ST) has a molocular weight of about 5000 to 10000 dalton. Moreover, isolectric focusing of the (ST) in a gradient pH of 6.3 to 2.5 indicated that the toxin has two fractions, designated ST1 and ST2, with isoelectric points of Pi = 3.1 and Pi 2.9, respectively. Further study revealed that both fractions had similar toxin effect in the gut of sucking mice