Biomedical subjects

Joanna Niedbach

Publications and source records attributed to Joanna Niedbach.

3 recordsLinked to original sources

PubMed2005

The action of photosensitizers and serum in a bactericidal process. II. The effects of dyes: hypericin, eosin Y and saphranine O.

The aim of the present work was to recognize the reasons for differences in the photodynamic action of dyes against various bacterial strains. It is expected that a better understanding of this problem may help in design of new photosensitizers. The sensitivity of 6 various bacterial strains to the photodynamic action of 5 photosensitizers was determined. The hydrophobicity of cell surface and susceptibility of bacteria to the natural defense mechanism of human serum, were estimated. The differences in the photodynamic efficiency of dyes could be contributed to various affinities of cell membrane to dyes, to known details of membrane architecture as well as to different mechanisms of photosensitization.

Anthracenes↗

PubMed2003

The factor C3 conversion in human complement by smooth Shigella flexneri lipopolysaccharides.

Shigella flexneri rods play an important role in human intestinal infections. In the presented studies we have shown that O-acetyl and glucose residues, substituted in main GalNAc-Rha chains of lipopolysaccharide (LPS) are important for the bactericidal effect of human serum. By dot-blot, immunoblotting and ELISA with immobilized LPS we have shown correlation of C3 fragments deposition and serum resistance. LPSs isolated from a serum-sensitive strain deposited more C3 fragments than LPSs from serum-resistant Shigella flexneri strains.

Blood Bactericidal Activity↗

PubMed2003

rep-PCR fingerptinting as a tool for the analysis of genomic diversity in Escherichia coli strains isolated from an aqueous/freshwater environment.

The rep-PCR fingerprinting method, with the support of ERIC and REP primers, was used to analyse the genomic diversity of 93 E. coli strains isolated from lake water samples drawn at two different depths. The applied UPGMA for DNA analysis did not reveale any genomic similarities between the 48 E. coli strains derived from the subsurface-zone water and the 43 of the bottom-zone water. The considerable genomic diversity of the E. coli of the surface zone was expressed as a dendrogram in the form of 8 similarity groups comprising strains isolated from samples drawn over one month. The bottom-zone strains, which display a lesser degree of genomic diversity (5 similarity groups), showed distinct common features in their DNA fingerprints. In the similarity dendrogram for the bottom-zone, strains derived in different months of sampling were segregated into the same similarity groups. Applying REP primers in rep-PCR generates more complex fingerprints increasing the discriminatory power of the analysis, whereas the ERIC primer generates less complex fingerprint patterns, and is thus clearer to interpret.

DNA Fingerprinting↗