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Visualization of Golgi apparatus in methacrylate embedded conifer embryo tissue using the monoclonal antibody JIM 84
D E Evans1, P J Clay, S Attree
1Department of Biology, University of Saskatchewan, Saskatoon, Canada.
Abstract:
Methacrylate embedding followed by resin removal has been used for the first time to visualize a membrane-associated antigen at the tissue level. Monoclonal antibody JIM 84 was used to stain the Golgi apparatus of gymnosperm (conifer) embryos by light microscope immunocytochemistry. Specificity of labelling was confirmed by electron microscope immunocytochemistry using LR-white resin. GA staining was evident in all stages of white spruce somatic embryo development from immature to mature. Some regions of the somatic embryos (e.g. root cap/suspensor region) stained more vigorously than other regions (hypocotyl/cotyledon end). GA also stained in roots of Monterey pine and Douglas fir. Unlike the situation in most angiosperms, JIM 84 antigen appears to be absent from the conifer plasma membrane. However, it appears to be present in representatives of both major classes of higher plants.
Insights
This study visualizes a membrane-associated antigen in conifer embryos using novel methacrylate embedding techniques. The Golgi apparatus (GA) stained prominently, revealing its presence across gymnosperm development.
Area of Science:
- Plant biology
- Immunocytochemistry
- Cell biology
Background:
- Membrane-associated antigens are crucial for understanding plant cell structure and function.
- Previous visualization methods have limitations in tissue-level analysis.
- The Golgi apparatus (GA) plays a vital role in plant development.
Purpose of the Study:
- To develop and apply a novel technique for visualizing membrane-associated antigens in gymnosperm embryos.
- To investigate the distribution and presence of the JIM 84 antigen in conifer somatic embryos.
- To compare antigen localization in gymnosperms with angiosperms.
Main Methods:
- Methacrylate embedding followed by resin removal for tissue-level antigen visualization.
- Light and electron microscope immunocytochemistry using monoclonal antibody JIM 84.
- Staining of white spruce, Monterey pine, and Douglas fir embryos and roots.
Main Results:
- Successful visualization of a membrane-associated antigen at the tissue level in gymnosperm embryos.
- Golgi apparatus (GA) staining was observed in all developmental stages of white spruce somatic embryos.
- Differential staining intensity was noted in various embryo regions, with stronger staining in root cap/suspensor regions.
- The JIM 84 antigen was detected in conifer roots but appeared absent from the plasma membrane, unlike in angiosperms.
Conclusions:
- Methacrylate embedding is an effective technique for visualizing tissue-level antigens in plant embryos.
- The JIM 84 antigen is present in the Golgi apparatus of gymnosperms, indicating its conserved role in higher plants.
- The absence of the JIM 84 antigen from the conifer plasma membrane suggests distinct plasma membrane compositions between gymnosperms and angiosperms.