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Electron microscopy of salivary gland viruses
Abstract:
A human and a mouse strain of the salivary gland virus have been examined by electron microscopy. The human strain was transmitted, prior to examination, to tissue cultures derived from human myometrial cells, while the mouse strain was examined in mice inoculated intraperitoneally. The nuclear forms associated with both strains of virus were morphologically similar. Nuclear inclusions, composed of particles interspersed with dense clumped chromatin, were a striking feature of infected cells. The cytoplasmic forms were of 2 types-one a 300 to 500 mmicro homogeneous dense spherical form, and the other a target-like form composed of a central dense dot in a pale zone surrounded by a dense shell-the entire configuration measuring 100 to 180 mmicro. The target-like particle appeared to be identical in both strains. The spherical cytoplasmic forms in cells infected with the human strain appeared to be solid, while in cells infected with the mouse strain there was evidence of formation of target-like forms within the spheres. Possible mechanisms by which infection of the cell may occur, as well as possible mechanisms and sites of multiplication of virus, are discussed.
Insights
Electron microscopy revealed similar nuclear forms in human and mouse salivary gland virus strains. Cytoplasmic forms differed, with human strains showing solid spheres and mouse strains exhibiting target-like structures within spheres.
Area of Science:
- Virology
- Cell Biology
- Microscopy
Background:
- Salivary gland viruses (SGVs) are significant pathogens in both humans and mice.
- Understanding the ultrastructural morphology of SGVs is crucial for elucidating viral replication and pathogenesis.
- Comparative analysis of different viral strains can reveal conserved and divergent features.
Purpose of the Study:
- To compare the ultrastructural morphology of human and mouse salivary gland virus strains using electron microscopy.
- To identify similarities and differences in viral forms within infected host cells.
- To discuss potential mechanisms of viral infection and replication based on observed morphology.
Main Methods:
- Human salivary gland virus strain examined in human myometrial cell cultures.
- Mouse salivary gland virus strain examined in intraperitoneally inoculated mice.
- Transmission electron microscopy used for ultrastructural analysis of infected cells.
Main Results:
- Morphologically similar nuclear viral forms observed in both human and mouse SGV strains.
- Distinct cytoplasmic viral forms identified: homogeneous dense spheres (300-500 nm) and target-like particles (100-180 nm).
- Target-like particles were identical in both strains; human strain showed solid spheres, while mouse strain exhibited sphere-to-target transformation.
Conclusions:
- Nuclear morphology of human and mouse SGV strains is conserved.
- Cytoplasmic viral morphogenesis shows strain-specific differences, particularly in the formation of target-like structures.
- The findings provide insights into potential viral entry and replication strategies for salivary gland viruses.
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