由粘菌变形虫产生和分泌的多脂体的命运。

The fate of multilamellar bodies produced and secreted by Dictyostelium discoideum amoebae.

机构信息

Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada; Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Hôpital Laval, Quebec City, QC, Canada; Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, QC, Canada.

出版信息

Eur J Cell Biol. 2017 Dec;96(8):767-773. doi: 10.1016/j.ejcb.2017.10.002. Epub 2017 Oct 14.

DOI:10.1016/j.ejcb.2017.10.002

PMID:29107380

Abstract

The amoeba Dictyostelium discoideum produces and secretes multilamellar bodies (MLBs) mainly composed of amoebal membranes upon digestion of bacteria. After their secretion, the fate of these MLBs remains unknown. The aim of this study was to determine if protozoa can internalize and digest secreted D. discoideum MLBs. Our results showed that MLBs were ingested by naive axenic D. discoideum cells (i. e. cells not exposed to bacteria and consequently not producing MLBs). Only a small fraction of the ingested MLBs were found in cells' post-lysosomes compared to undigestible beads suggesting that naive amoebae digest them. D. discoideum MLBs were also ingested by the ciliates Tetrahymena pyriformis and Tetrahymena thermophila. MLBs internalized by the ciliates were compacted into pellets and expelled in the extracellular medium without obvious signs of degradation. The results of this study provide new insights on the biological function of MLBs and, considering that MLBs are also involved in bacteria packaging, suggest additional layers of complexity in microbial interactions.

摘要

变形虫 D. discoideum 在消化细菌时会产生并分泌主要由变形虫膜组成的多层体（MLBs）。这些 MLBs 分泌后其命运仍不清楚。本研究旨在确定原生动物是否可以内化和消化分泌的 D. discoideum MLB。我们的结果表明，MLBs 被未接触细菌（因此不产生 MLB）的原始无菌 D. discoideum 细胞内化。与不可消化的珠子相比，只有一小部分被内化的 MLB 存在于细胞的溶酶体后体中，这表明原始变形虫可以消化它们。纤毛虫 Tetrahymena pyriformis 和 Tetrahymena thermophila 也可以摄取 D. discoideum MLB。被纤毛虫内化的 MLB 被压缩成小球，并在没有明显降解迹象的情况下被排出到细胞外介质中。本研究的结果为 MLB 的生物学功能提供了新的见解，并且考虑到 MLB 也参与了细菌包装，这表明微生物相互作用具有更多的复杂性。