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Biomedical subjects

A Zamir

Publications and source records attributed to A Zamir.

At least 73 records · Page 4Linked to original sources
PubMed1974

Active insolubilized antibiotics based on cellulose-metal chelates.

Cellulose was converted into a more reactive form by chelation with the transition metals titanium(III), iron(III), tin(IV), vanadium(III), and zirconium(IV). The remaining unsubstituted ligands of the transition metal ions were found to be amenable to replacement by electron-donating groups of antibiotic molecules. Ampicillin, gentamicin, kanamycin, neomycin, paromomycin, polymyxin B, and streptomycin were used as antibacterial antibiotics, and amphotericin B and natamycin were used as antifungal antibiotics. Antibacterial activity of the products was tested against two gram-positive and two gram-negative bacteria, and antifungal activity was tested against four fungi. That the antibacterial antibiotics had complexed with the cellulose-metal chelates was demonstrated in that the product cellulose-metal-antibiotic chelates exhibited antibiotic activities whereas the metal chelates of cellulose themselves were inactive. Of 140 tests conducted, cellulose-metal-antibiotic chelates were active in 102 cases. Since the antibiotic derivatives were water insoluble and in fact retain some of the antibacterial activities of the parent compounds, the chelation method provides a facile way of rendering cellulose surfaces, etc., resistant to microbial attack over and above that degree of protection afforded by noncovalent adsorption of the antibiotic to cellulose itself. The underlying principles of the chelation reactions involved are discussed in detail.

Anti-Bacterial Agents↗
PubMed1973

Mapping of Escherichia coli ribosomal components involved in peptidyl transferase activity.

The method of affinity labeling has been used to identify protein components of 50S ribosomal subunits involved in peptidyl transferase activity. E. coli 50S ribosomal subunits were mapped by reaction with the N-bromoacetyl analog of chloramphenicol, an antibiotic known to interact specifically with the active center of the enzyme. The synthetic analog competes with chloramphenicol in binding to 50S ribosomal subunits and inhibits peptidyl transferase activity. It attaches covalently to the ribosome under appropriate conditions and causes an irreversible loss in peptidyl transferase activity. The reagent specifically alkylates cysteine residues of proteins L2 and L27.

Acetamides↗