Sohal R S, Peters P D, Hall T A
Tissue Cell. 1976;8(3):447-58. doi: 10.1016/0040-8166(76)90005-7.
The epithelium and the lumen of the Malpighian tubules of the housefly contains mineralized dense bodies called concretions. The morphological characteristics, mode of origin, nature of the sequestered elements and the age-associated changes in the distribution of concretions are reported. There are three types of concretions in the cytoplasm, which have been designated as type A, type B, and type C. Type A concretions are membrane-bound spherical structures which may arise by the gradual intravacuolar accumulation of dense material. Type B concretions appear to be related to multivesicular bodies. Type C concretions are heteromorphic and morphologically resemble the residual bodies. They show a positive localization of acid phosphatase reaction product. X-ray microanalysis of intracytoplasmic and intraluminal concretions revealed the presence of phosphorus, sulphur, chlorine, calcium, iron, zinc and copper. There was no evidence suggesting the extrusion of the intracytoplasmic concretions into the lumen of the Malpighian tubules. There is an age-associated increase in the distribution of type C concretions. It is hypothesized that the sequestration of metal ions within the concretions may provide a means for the effective excretion of these elements.
家蝇马氏管的上皮和管腔含有矿化的致密体，称为结石。本文报道了结石的形态特征、起源方式、所含元素的性质以及与年龄相关的分布变化。细胞质中有三种类型的结石，分别被指定为A型、B型和C型。A型结石是膜结合的球形结构，可能由致密物质在液泡内逐渐积累形成。B型结石似乎与多泡体有关。C型结石形态各异，在形态上类似于残余体。它们显示出酸性磷酸酶反应产物的阳性定位。对细胞质内和管腔内结石的X射线微分析显示存在磷、硫、氯、钙、铁、锌和铜。没有证据表明细胞质内的结石会排入马氏管腔。C型结石的分布随年龄增长而增加。据推测，结石内金属离子的隔离可能为有效排泄这些元素提供一种方式。
