PubMed Health⌕ Search

Biomedical subjects

Z Holan

Publications and source records attributed to Z Holan.

8 recordsLinked to original sources

Tumor necrosis factor and its induction by bacterial endotoxins.

Using suitable immunomodulators (Corynebacterium parvum vaccine, Zymosan or muramyl dipeptide), lipopolysaccharides (LPS) from various members of the family Enterobacteriaceae (Escherichia, Salmonella, Serratia, Shigella) were tested on rabbits in relation to the production of tumor necrosis factor (TNF). TNF was determined by means of the serum titration of L-929 cell cultures in the presence of Actinomycin D, this with resulting titres of 3.2 x 10(3) to 5.1 x 10(4) IU TNF/ml. Analogous titres were noted after the action of denatured LPS (ie LPS subjected to alkaline hydrolysis or H2O2).

Adjuvants, Immunologic↗

Preparation of zymosan from yeast cell walls.

Cell walls of the yeast Saccharomyces cerevisiae after disintegration and protoplasm removal by centrifugation and repeated washing were suspended in 0.5 M Na2HPO4, pH 7.8-8.0, as a 5% or 10% suspension, depending on the mode of heating. The suspension was boiled for 3 h, purified by repeated washing with water and ethanol and dried. The yield was approximately 1.8% of the starting amount of pressed commercial baker's yeast.

Cell Wall↗

Cytological and chemical changes in cell walls of Rhodotorula gracilis. III. Characteristics and life cycle of the yeast.

The phenotype and genotype of six strains of the genus Rhodotorula Harrison and of one strain of the genus Cryptococcus Phaff et Fell, with anomalous thickening of cell walls were investigated. The present studies showed that the strains investigated represent different stages of the life cycles of the genus Rhodosporidium Banno. The anomalous thickening of the cell walls can be explained by extreme conditions resulting in the formation of surviving forms (teliospores, chlamydospores).

Bacterial Proteins↗

The chitin-glucan complex of Saccharomyces cerevisiae. III. Electron-microscopic study of the prebudding stage.

Differentiation of the cell wall of Saccharomyces cerevisiae at the site of the future bud was followed. A lentil-like structure originates on the inner side of the cell wall during the first phase. At the same time, an electron-dense layer occurs at the boundary between the inner layer of the cell wall and the lentil-like structure. During the second phase granular material is accumulated at the lower side of the lentil-like structure. During the third phase the lentil-like structure is split apart due to proliferation of the granular material resulting in formation of the base of the encircling region. The marked electron-dense layer observed from the first phase is attached to the surface of the encircling region during differentiation of the latter. During the budding proper the outer layers of the cell wall protrude and the end of the encircling region, together with the adjacent electron-dense layer, acquire their definitive appearance of rings, observed as marked electron-transparent and electron-dense tears on ultrathin sections.

Cell Division↗