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Biomedical subjects

F Mayer

Publications and source records attributed to F Mayer.

At least 235 records · Page 13Linked to original sources
PubMed1975

In situ preformed auto-alloplastic replacement in the treatment of femoropopliteal vascular obstruction.

A method of in situ preformed auto-alloplastic replacement for the treatment of long femoro-poplitela vascular obstructions is described on the basis of highly promising experimental results. A macropouous tube made of aplastic net and obturated with a silicone rubber mandril was implanted next to the obstructed vascular section. The two ends of the live auto-alloplastic tube formed in situ around the mandril were joined in a second operation to the femoral and popliteal arteries. Early experience is described on grounds of four cases, together with the current and possible future indications of the operation.

Adult↗
PubMed1974

Plain and complex flagella of Pseudomonas rhodos: analysis of fine structure and composition.

Cells of Pseudomonas rhodos 9-6 produce two morphologically distinct flagella termed plain and complex, respectively. Fine structure analyses by electron microscopy and optical diffraction showed that plain flagellar filaments are cylinders of 13-nm diameter composed of globular subunits like normal bacterial flagella. The structure comprises nine large-scale helical rows of subunits intersecting four small-scale helices of pitch angle 25 degrees . Complex filaments have a conspicuous helical sheath, 18-nm wide, of three close-fitting helical bands, each about 4.7-nm wide, separated by axial intervals, 4.7 nm wide, running at an angle of 27 degrees . The internal core has similar but not identical substructure to plain filaments. Unlike plain flagella, the complex species is fragile and does not aggregate in bundles. Mutants bearing only one of two types of flagellum were isolated. Cells with plain flagella showed normal translational motion, and cells with complex flagella showed rapid spinning. Isolated plain flagella consist of a 37,000-dalton subunit separable into two isoproteins. Complex filaments consist of a 55,000-dalton protein; a second 43,000-dalton protein was assigned to complex flagellar hooks. The results indicate that plain and complex flagella are entirely different in structure and composition and that the complex type represents a novel flagellar species. Its possible mode of action is discussed.

Bacterial Proteins↗
PubMed1973

Electron microscopy study of length and partial denaturation of Rhizobium bacteriophage DNA.

By electron microscopy and melting of the DNA of some bacteriophages from the soil bacterium Rhizobium lupini, it was found that molecular weights range between 27 and 50 Mdaltons and GC contents between 53 and 62%. All DNAs studied are linear; one has exposed single-stranded terminals. Partial heat denaturation of two phage DNA permitted mapping of AT-rich sites within unique nucleotide sequences. The maps are asymmetric with respect to the midpoints of the DNA.

Bacteriophages↗
PubMed1972

Isolation and characterization of a bacteriophage tail-like bacteriocin from a strain of Rhizobium.

Bacterial strain 16-3 spontaneously produces a bacteriocin which inhibits the growth of closely related strain 16-2. Both strains were newly isolated from root nodules of lupines and probably belong to the species Rhizobium lupini. Production of infectious progeny of newly isolated virulent phage 16-2-4 in strain 16-2 is inhibited completely if complexes are bacteriocin-treated during the first half of the latent period. Treatment begun during the second half leads to premature lysis of complexes and inactivates only those progeny phages which were not yet fully matured at the moment of the particle-induced lysis. Examination by electron microscope of the bacteriocin enrichment revealed the presence of particles 123 nm in length which resemble the tails of T-even bacteriophages. Since the particles sediment together with the bactericidal activity in the sucrose gradient and adsorb specifically to bacteriocin-sensitive cells, it is concluded that they are identical with the bactericidal agent. The particles are not found attached to phage heads and cannot self-propagate; they are regarded as incomplete and are named INCO particles. INCO particles consist of a core enveloped by a contractile sheath. One end of the sheath is connected to a baseplate to which six fibers, each 32 nm in length, are attached. These connect the baseplate of an adsorbing particle to the cell surface. Since INCo cores are probably empty, it is concluded that specific adsorption of the particles to the bacterial surface is sufficient to inactive sensitive cells irreversibly.

Acetates↗