조직내 및 배양기내 자유생활 아메바의 전자현미경적 비교 연구

Abstract

[한글]

Limax 아메바에서 생활사의 각 단계에 따라 미세구조의 차이가 있으며 (Vickerman, 1960, 1962: Schuster 1963 a, b: Bewer & Korn, 1968, 1969), 또 같은 영양형일지라도 환경에 따라 미세구조가 달라진다고 보고되어 있다. Maitra등(1974a, b)은 Hartmanella culbertsoni 영양형이 무균배양기, monobacterial 배양기 및 실험적으로 감면시킨 마우스 뇌조직의 각각에서 mitochondria, 골기체, spongiome, 식포 등에 있어 차이가 있음을 관찰하였고 Naegleria serobia도 배양기와 실험적으로 감염시킨 마우스 뇌조직에서의 영양형에서 mitochondria 및 ribosome에 있어 차이가 있음을 관찰하였다. 고로 본 연구에서는 자유생활아메바가 같은 영양형일지라도 환경에 따라 신진대사가 다를 것으로 생각되어 환경에 따른 아메바의 미세구조의 변화를 관찰하였다.

본 실험에서 사용한 N. fowleri 0359 strain은 무균 액체배지인 CGVS 배지에서 7년이상 배양한 것이고 마우스에의 감염은 복강내로 secobarbital을 넣어 마취시킨후 1×10**5개의 아메바를 코를 통해 감염시켜 7일후 감염된 뇌조직을 전자현미경을 이용하여 비교관찰한 결과 다음과 같은 성적을 얻었다.

1. 마우스 뇌조직내의 아메바는 다소 둥근모양인데 반해 배양기내의 영양형은 다소 불규칙한 모양을 보였다.

2. 배양기내 아메바의 mitochondria는 난원형, 구형, 원통형등 형태가 다양한데 비하여 마우스 뇌조직내 아메바에는 이외에 아령모양이 특이하게 있었고 배양기내 아메바의 mitochondria는 진하게 보였으나 마우스 뇌조직내의 아메바에서는 진한 것과 흐린 것이 다있었다.

3. 조면세포질내세망(rER)의 형태에 있어 마우스 뇌조직내 아메바에서는 세관(microtubule)모양으로 있는데 비해 배양기내 아메바에는 세관모양 이외에 소낭(vesicle) 모양이관찰되었다. Ribosome은 배양기내에서는 free ribosome이 많은 반면 마우스 뇌조직내 아메바에서는 polysome이 많았다.

4. 배양기 아메바에서는 내용물이 없는 액포(vaculoe)가 많았고 마우스 뇌조직내 아메바에는 식포(food vacuole)가 많고 그안에 미엘린양 구조가 존재함을 보았다. 이것으로아메바는 마우스 뇌조직에서 강한 식작용이 있는 것으로 생각된다.

5. N. fowleri에 감염된 마우스 뇌조직은 손상되었고 염증세포로는 다핵백혈구가 많었고 아메바는 혈관주위에 많았다.

Ultrastructural observation of Naegleria fowleri trophozoite in Mouse brain and

axenic culture

Jae Sook Ryu

Department of Medical Science The Graduate School, Yonsei University

(Directed by Prof. Chin-Thack Soh, M.D.)

Present study was undertaken to elucidate the changes of the ultrastructure of

Naegleria fowleri trophozoite in brain tissue of mice and culture medium. Naegleria

fowleri, 0359 strain, which used in this study was cultured in axenic liquid

medium, CGVS medium. Each mouse was inoculated with 1×10**5 amoebas intranasally

under secobarbital anesthesia, and sacrificed on 7th day after the infection.

Comparative observation of the ultrastructure of the amoebas in axenic culture and

experimentally infected mice brain was done with transmission electron microscope.

The results are summarized as follows;

1. The amoebas in mouse brain tissue were round in outline, whereas those of the

amoebas from axenic culture showed irregular appearance.

2. Mitochondria in the amoebas from axenic culture was oval, round and

cylindrical shape and darkly stained. whereas those of the amoebas from mouse brain

tissue showed dumbbell shape together with above forms. The stain was not unique,

but light or/and dark.

3. Rough endoplasmic reticulum of amoebas in brain tissue was tubular, but from

culture it was vesicular or tubular in shape.

4. Empty vacuoles were demonstrated in amoebas from culture, while food vacuoles

with myelinated structures were abundant in those from tissue, suggesting a strong

phagocytic activity.

5. Mouse brain tissue infected were extensively destroyed, and polymorphonuclear

leukocytes were infiltrated predominantly with inflammatory lesion. Amoebas were

observed in the vicinity of the capillary.

[영문]

Present study was undertaken to elucidate the changes of the ultrastructure of Naegleria fowleri trophozoite in brain tissue of mice and culture medium. Naegleria fowleri, 0359 strain, which used in this study was cultured in axenic liquid medium, CGVS medium. Each mouse was inoculated with 1×10**5 amoebas intranasally under secobarbital anesthesia, and sacrificed on 7th day after the infection.

Comparative observation of the ultrastructure of the amoebas in axenic culture and experimentally infected mice brain was done with transmission electron microscope.

The results are summarized as follows;

1. The amoebas in mouse brain tissue were round in outline, whereas those of the amoebas from axenic culture showed irregular appearance.

2. Mitochondria in the amoebas from axenic culture was oval, round and cylindrical shape and darkly stained. whereas those of the amoebas from mouse brain tissue showed dumbbell shape together with above forms. The stain was not unique, but light or/and dark.

3. Rough endoplasmic reticulum of amoebas in brain tissue was tubular, but from culture it was vesicular or tubular in shape.

4. Empty vacuoles were demonstrated in amoebas from culture, while food vacuoles with myelinated structures were abundant in those from tissue, suggesting a strong phagocytic activity.

5. Mouse brain tissue infected were extensively destroyed, and polymorphonuclear leukocytes were infiltrated predominantly with inflammatory lesion. Amoebas were observed in the vicinity of the capillary.