アメーバの細胞質に存在する微小顆粒と結晶の形態と元素組成の比較

type:P(論文)

アメーバのA. proteusとp. dubiumの二種と餌生物のP. bursaliaの細胞内に見られる微小顆粒と結晶を光顕,TEMとSEMを用いて形態観察を行うとともに,走査型X線マイクロアナライザーを用いて元素分析を行い,それらの形態と元素組成の比較を行った.光顕とSEMによる観察で,A. proteusでは多数の小さな微小顆粒とバイピラミッド型の結晶が,P. dubiumでは多数の微小顆粒と大きさの異なる矩形層板状型の結晶が,そしてP. bursaliaでは微小顆粒と大きさの異なる不規則な形の結晶が観察された.アメーバの結晶をトルイジンブルー染色した厚切り樹脂切片を観察すると,A. proteusでは結晶の全体が,P. dubiumでは結晶の表層部が濃青色に染色された.走査型X線マイクロアナライザーで微小顆粒と結晶の元素分析を行った結果,微小顆粒と結晶の元素組成はA. proteusとP. dubiumの間に違いが認められず,結晶の元素組成はC, N, Oであり,微小顆粒ではC, N, O, Mg, P, Caであった.P. bursaliaでは微小顆粒と結晶の元素組成に違いが認められなかった.アメーバとP. bursaliaの間では無機成分にわずかな違いが認められた.これらの結果から,アメーバの微小顆粒と結晶は餌生物のP. bursaliaの微小顆粒や結晶に由来するのではなく,各アメーバ自身が合成したものと考えられる.また,アメーバの結晶は元素組成からNを含む有機物の貯蔵に,微小顆粒は無機物の貯蔵や細胞内のイオン濃度の維持に関与していると考えられる.

In order to compare the difference of crystals and microgranules among Amoeba proteus, Polychaos dubium and the food organism chlorella free Paramecium bursalia collected from a natural freshwater pond, a study was performed using a light microscope (LM), transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray microanalyser. LM and SEM observation of the cytoplasm of A. proteus revealed numerous microgranules and small crystals of bipyramidal form, that of P. dubium revealed numerous microgranules and large crystals of platelike rectangular form, and that of P. bursalia revealed numerous microgranules and irregular shaped crystals. By using LM observation of a toluidine blue stained thick resin section, the outer layer of each crystal in P. dubium and the whole of each crystal in A. proteus was dyed dense ultramarine. The results of X-ray microanalysis showed as follows: The elemental composition of microgranules and crystals did not differ between the two species of A. proteus and P. dubium, and the elemental composition of both crystals consisted mainly of carbon, nitrogen and oxygen, and that of microgranules consisted of the same elements as crystals, plus the inorganic components magnesium, phosphorus, potassium, chlorine, and calcium. In P. bursalia no difference of the elemental composition between microgranules and crystals was observed. The inorganic component of the elemental composition of the microgranules and crystals was slightly different between amoebae and P. bursalia. These results indicate that the crystals and microgranules of amoebae were not derived from the food organism P. bursalia but were originally synthesized in each cell, that the crystals of amoebae could be deposits or reservoirs of organic materials containing nitrogen, and that microgranules of amoebae could be deposits and reservoirs of certain ions and could be involved in the regulation of ion levels in the cell.