Joost M. Leunissen

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In order to localize the information within PhoE protein of Escherichia coli K-12 required for export of the protein to the outer membrane, we have generated deletions throughout the phoE gene. Immunocytochemical labelling on ultrathin cryosections revealed that the polypeptides encoded by the mutant alleles are transported to, and accumulate in, the(More)
This study describes the ultrastructural localization in rat hippocampal tissue in situ and in isolated synaptosomes of the brain-specific phosphoprotein B-50, using affinity purified anti-B-50 immunoglobulins (IgGs). Evidence is presented for the presynaptic localization of B-50 in rat brain. Given this specific localization a model is presented outlining(More)
Pre-embedding double immunogold-silver labeling using two ultrasmall gold conjugates has not been attempted previously because a means of distinguishing labels by conjugates of identical sizes was lacking. This study investigated the feasibility of creating a particle size segregation between two ultrasmall gold conjugates through sequential immunogold(More)
A new method is reported for the preparation of colloidal gold particles with diameters ranging between 5 and 12 nm. The initial gold particle population, with an average diameter of 5.6 +/- 0.9 nm, is prepared by reduction of chloroauric acid with white phosphorous. An increase in particle diameter by growth is obtained by reduction of chloroauric acid(More)
A method is described for the cryofixation of biological specimens for ultrastructural analysis and immunocytochemical detection studies. The method employs plunge freezing of specimens in a sealed capillary tube into a cryogen such as liquid propane or liquid nitrogen. Using this method a number of single-cell test specimens were well preserved. Also(More)
In this paper we describe immunocytochemical detection of PhoE pore protein in the outer membrane of E. coli K-12 cells in dependence of a variety of labelling approaches. Immuno-gold labelling on ultrathin cryosections showed a uniform, dense labelling of the outer membrane of all cells. However, using immunofluorescence, whole-mount or freeze-etch(More)
An antibody against the non-specific lipid transfer protein from rat liver was purified by immunoabsorbent affinity chromatography. This antibody in conjunction with protein A-colloidal gold was used to localize the transfer protein in rat liver by electron microscopy. Labeling by this immunocytochemical technique was found to be mainly restricted to the(More)
A phoE-lacZ hybrid gene encoding the N-terminal 300 amino acid residues of pre-PhoE protein, fused to an almost complete beta-galactosidase molecule was constructed in vitro. Cell fractionation experiments suggested that the hybrid gene product is transported to the outer membrane. However, by using immuno-cytochemical labelling on ultra-thin cryosections(More)
Cryo-ultramicrotomy in combination with immuno-gold labeling has been demonstrated to present a powerful tool in the visualization of extra- and intracellular located antigens. We have applied this method to localize epidermal growth factor (EGF) receptor in cultured A431 human epidermoid carcinoma cells. However, both the labeling efficiency, maintenance(More)
The localization of S-antigen, the soluble, uveitogenic, 51 kDa protein of the retina has been studied. Highly specific rabbit anti-bovine S-antigen antiserum reacted predominantly with the outer segment layer of the photoreceptor cells of rat retina in the indirect immunofluorescence technique, provided that the tissue was fixed by perfusion of the light(More)