TY - JOUR
T1 - Effect of artificial gastrointestinal fluids on the excystation and metacystic development of Entamoeba invadens
AU - Makioka, Asao
AU - Kumagai, Masahiro
AU - Kobayashi, Seiki
AU - Takeuchi, Tsutomu
N1 - Funding Information:
Acknowledgements We thank Dr. N. Watanabe for valuable discussion, Dr. L.S. Diamond for supplying the E. invadens, and T. Tadano for technical assistance. This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports and Technology of Japan and by a Health Science Research Grant for Research on Emerging and Re-emerging Infectious Diseases from the Ministry of Health, Labor and Welfare of Japan.
PY - 2006/4
Y1 - 2006/4
N2 - 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°C but not 26°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°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°C contributes to enhancing excystation for Entamoeba infection.
AB - 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°C but not 26°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°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°C contributes to enhancing excystation for Entamoeba infection.
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U2 - 10.1007/s00436-005-0025-7
DO - 10.1007/s00436-005-0025-7
M3 - Article
C2 - 16416121
AN - SCOPUS:33645241769
SN - 0044-3255
VL - 98
SP - 443
EP - 446
JO - Zeitschrift fur Parasitenkunde
JF - Zeitschrift fur Parasitenkunde
IS - 5
ER -
