Viroplasm

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Immunofluoreszenzaufnahme replication complexes of BVDV ( bovine viral diarrhea virus , red) in MDBK cells ( english Madin-Darby bovine kidney , cell cultures of epithelial cells from bovine kidney). The cell nuclei are stained blue with DAPI .

As Viroplasm ( English Viroplasm ) refers to that place within a virus-infected cell, where the actual production of viral components takes place ( English virus factory, factory virion , VF). In most cases, the viroplasm can be recognized or assumed by morphological changes compared to a non-infected cell under the electron microscope ; in many cases, however, there is no direct evidence. An example of this is the so-called recently described "membranous network" ( English membranous web ) in cells with a replicon of the Hepatitis C virus transfected were. Here the viroplasm appeared as an agglomeration of membrane complexes within the cytoplasm .

Viroplasma (green) in cells infected by rotavirus (top), uninfected cells (bottom). (Immunofluorescence images)

In the case of some viruses, the viroplasm can already be recognized under the light microscope, either using certain staining methods or through clear cytological changes. These changes were already in the early days of cellular pathology as " inclusion bodies (" English body inclusion, X-body ) described and later attributed to the virus propagation. Some of these are deposits of viral proteins or virus particles, but mostly particularly extensive and modified regions of the endoplasmic reticulum or the Golgi apparatus , which are used for virus replication. An example of these cytoplasmic inclusion bodies are the Negri bodies (named after their discoverer, the pathologist Adelchi Negri ) in cells that reproduce the rabies virus .

The viroplasm can be located in the cytoplasm as well as in the cell nucleus ( caryoplasm ). As a nuclear viroplasm, it is only found in the cell nucleus in viruses that require cellular DNA or RNA polymerases to multiply (e.g. polyomaviruses and herpes viruses ).

swell

  • Reyes R. Novoa, Gloria Calderita, et al. : Virus factories: associations of cell organelles for viral replication and morphogenesis . Biology of the Cell (2005) 97: pp. 147-172, PMID 15656780

Individual evidence

  1. Graziel Oliveira, Bernard La Scola, Jônatas Abrahão: Giant virus vs amoeba: fight for supremacy , in: Virol J 16, 126, November 4, 2019, doi: 10.1186 / s12985-019-1244-3 , PDF