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B Bartos

Publications and source records attributed to B Bartos.

3 recordsLinked to original sources

Intracellular distribution of photosensitizing porphyrins measured by video-enhanced fluorescence microscopy.

The intracellular distribution of photosensitizing porphyrins with different amounts of aggregates was measured in a fluorescence microscope using video-intensified detection and image processing. Porphyrin fluorescence was localized in the plasma membrane, cytoplasm, nuclear membrane and nucleoli. The fluorescence intensity in the plasma membrane decreased with increasing aggregation of the photosensitizers. In addition, a redistribution of the porphyrin molecules from the plasma membrane to the nuclear membrane and adjacent intracellular sites was observed with increasing incubation time. Photobleaching of porphyrin fluorescence was most pronounced in the plasma membrane and least efficient within the nucleoli.

Chromatography, High Pressure Liquid

Carboxyl-terminal sequence of entactin deduced from a cDNA clone.

Entactin is a widely distributed basement membrane sulfated glycoprotein of approximately equal to 150 kDa. The entactin gene is expressed early in mouse embryogenesis. Two cDNA clones complementary to rat entactin mRNA were isolated by antibody screening of an oligo(dT)-primed cDNA library constructed in the lambda gt11 expression vector. One of the clones, lambda 1E, was subcloned into plasmid pBR322 and further characterized. The clone contained sequences complementary to an mRNA species 6 kilobases in length. This mRNA was translated in rabbit reticulocyte lysates to yield a polypeptide of 143 kDa that was precipitated with anti-entactin antiserum. The cDNA insert, 1328 base pairs long, was sequenced and found to contain an open reading frame of 729 base pairs that coded for 243 amino acids at the carboxyl terminus of entactin. Analysis of the peptide revealed no extended alpha-helical or beta-sheet secondary structures. Radiolabeled probes prepared by nicktranslation of p lambda 1E were used to monitor the steady-state levels of entactin mRNA in F9 embryonal carcinoma cells that were induced to differentiate by exposure to retinoic acid and dibutyryl cyclic AMP. The increase in steady-state levels of entactin mRNA lagged behind the increase in mRNA for the B2 chain of laminin, suggesting that laminin and entactin are independently rather than coordinately regulated.

Amino Acid Sequence