Effect of artificial gastrointestinal fluids on the excystation and metacystic development of Entamoeba invadens

Abstract

The effect of artificial gastric fluid (AGF), containing 0.5% pepsin and 0.6% hydrochloric acid, pH 1.8, in distilled water, on the excystation and metacystic development of Entamoeba invadens was examined. Excystation, which was assessed by counting the number of metacystic amoebae after inducing excystation, was enhanced by pretreatment of cysts with AGF for 30 to 60 min at 37 degrees C but not 26 degrees C. Longer exposure of cysts to AGF significantly reduced their viability. Significant enhancement of excystation was observed by pretreatment of cysts with distilled water only at 37 degrees C. In addition, 0.6% hydrochloric acid had a comparable enhancing effect on excystation to AGF. Metacystic development, when determined by the number of nuclei in amoeba, was slightly enhanced by pretreatment with AGF. An artificial intestinal fluid (AIF), containing 1% pancreatin, 1% sodium bicarbonate, and 5% ox bile, pH 8.0, in distilled water, had a significant toxic effect on cysts, where 1% pancreatin had neither an enhancing effect on excystation nor a toxic effect on cysts, whereas 5% ox bile had a toxic effect on cysts. Pretreatment of cysts with AGF followed by AIF had a similar toxic effect on cysts to that by AIF only. These results suggest that gastric fluid but not intestinal fluid at 37 degrees C contributes to enhancing excystation for Entamoeba infection.

Compounds of the upper gastrointestinal tract induce rapid and efficient excystation of Entamoeba invadens

“…Another report previously described the use of compounds found in the upper GI tract on E. invadens excystment (Makioka, 2006). In that study excystment was increased in response to exposure to combinations of compounds that are different from those described here, and the resulting rates of excystment were considerably slower than those obtained with the water/bicarbonate/bile treatment described here.…”

Microbial Phosphorylation Product of Hesperetin by Bacillus subtilis BCRC 80517 Improves Oral Bioavailability in Rats

“…Stability Assay of HstPs and Hst in Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF). SGF and SIF were prepared as described in the United States Pharmacopeia and by Makioka et al 26 SGF consisted of 5 g of pepsin in 1000 mL of deionized water with hydrochloric acid at pH 1.8. SIF contained 6.8 g of monopotassium phosphate and 10 g of pancreatin in 1000 mL of deionized water at pH 6.8.…”

Obesity prevention of synthetic polysaccharides in high-fat diet fed C57BL/6 mice

“…Digestibility of polysaccharides was carried out based on the method previously reported (Makioka, Kumagai, Kobayashi, & Takeuchi, 2006). Artificial gastric juice (AGJ) contained pepsin (1%, w/v) and hydrochloric acid, pH 1.5.…”