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Biomedical subjects

G A De Zoeten

Publications and source records attributed to G A De Zoeten.

14 recordsLinked to original sources
PubMed1989

The expression, localization, and effect of a human interferon in plants.

The ORF II of Cauliflower mosaic virus (CaMV) DNA was replaced with the human IFN alpha D coding sequence to yield a stable CaMV strain designated Ca524i. Inoculation of turnip (Brassica rapa cv "Just Right") with strain Ca524i DNA excised from plasmid pCa524i resulted in the production of biologically active IFN alpha D in infected plants. This was also true for its mutant (Ca562i) where one of the CYS codons was deleted. IFN alpha D produced in planta did not hamper superinfection with a single-stranded (+) sense RNA plant virus, turnip yellow mosaic virus (TYMV). Antibody gold labeling techniques and electron microscopy of infected plants showed that IFN was localized in the CaMV inclusion bodies.

Cell Compartmentation↗
PubMed1970

The effects of tentoxin on chlorophyll synthesis and plastid structure in cucumber and cabbage.

To determine if chlorosis caused by tentoxin, a toxin produced by Alternaria tenuis Nees., is due to interference with chlorophyll synthesis directly or to disruption of normal chloroplast development, the effects of the toxin on these processes in cucumber (Cucumis sativus L.) and cabbage (Brassica oleracea L., var. capitata) were studied. Cucumber cotyledons are highly sensitive to the toxin but exhibited no interference with the conversion of protochlorophyll(ide) to chlorophyll(ide) or with the general time course pattern of chlorophyll synthesis, although there was a 90% reduction in chlorophyll concentration. In cabbage, which shows no chlorosis in the presence of the toxin, there was a slight stimulation of chlorophyll synthesis in the presence of the toxin. Electron microscopy revealed that in cucumber, toxin treatment interferes with development of prolamellar bodies and lamellae, and results in deformed plastids. No such effects were noted in toxin-treated cabbage tissues. Plastids in toxin-treated cotyledons of both cucumber and cabbage contained more starch than plastids in nontreated tissues. It was concluded that tentoxin acts through disruption of normal plastid development, rather than through direct interference with chlorophyll synthesis.

Chlorophyll↗
PubMed1969

Possibilities for inter- and intracellular translocation of some icosahedral plant viruses.

Southern bean mosaic virus (SBMV) and Tomato ringspot virus (TomRV) were compared with regard to possible ways of inter- and intracellular translocation. The pore complexes in the nuclear membranes of nuclei in leaf palisade and mesophyll cells of several plant species commonly used in plant virus research were studied. The pore structure resembled that earlier described. The diameter of the pores was great enough to allow icosahedral plant viruses between 25 and 30 mmicro wide to move through. SBMV occurred in noncrystalline form in nuclei of infected cells. Although this virus forms paracrystalline structures when partially purified, no virus crystals were seen in the cytoplasm of cells containing high concentrations of SBMV. It was established that this virus could move through nuclear pores. TomRV was found in infected leaf tissue in low concentrations. This virus showed a tendency to crystallize even when present in low concentrations. TomRV was observed only in the cytoplasm, not in nuclei. This virus was present in plasmodesmata, indicating the possibility of cell to cell translocation of whole particles through these structures.

Cytopathogenic Effect, Viral↗