Following damage by pore forming toxins (PFTs) host cells engage repair processes and display profound cytoskeletal remodeling and concomitant plasma membrane (PM) blebbing. We have recently demonstrated that host cells utilize similar mechanisms to control cytoskeletal dynamics in response to PFTs and during cell migration. This involves assembly of cortical actomyosin bundles, reorganisation ...

An obligate intracellular rickettsial organism isolated from an aborted bovine fetus was studied in bovine turbinate and mouse macrophage cell cultures with light and electron microscopy. Development of the organism was similar in both cell types. The organism replicated within cytoplasmic vacuoles in a developmental cycle that resembled that of both the ehrlichiae and chlamydiae. The inoculum ...

Prolonged administration of cycloheximide, an inhibitor of ribosomal protein synthesis, induces degeneration of rabbit taste bud cells: the degenerative changes resemble early changes in denervated taste buds. Our observations show that the pattern of degeneration is quite different in the three cell types of the taste buds. The earliest changes in type II and III cells are an increase in cytop...

Macromomycin is shown to inhibit the biosynthesis of RNA, DNA, and protein in cultured cells of KB, HBL-100, SW-613, MCF-7, and A1Ab. There was no substantial increase in cell numbers in cultures containing macromomycin (5 microgram/ml), but after 24 to 48 hr the cells were two to three times the diameter of control cells with concomitant increase in cell protein. The ultrastructural changes in...

The Neurospora crassa cot-1 gene encodes a Ser/Thr protein kinase, which is involved in hyphal elongation. Many vacuoles, abnormally shaped mitochondria, and nuclei, along with differences in the structure of the cell wall and hyphal septa, were observed in hyphae of the cot-1 mutant shortly after a shift to the restrictive temperature. Immunolocalization experiments indicated that COT1 was ass...

Sections of hydra studied with the electron microscope show various structures which have been identified by referring to control histological sections and to previous descriptions. Certain features have also been examined in frozen-dried sections under the light microscope. In the ectoderm, epithelio-muscular cells contain various organelles, and also smooth longitudinal muscle-fibres with whi...

The effect of ultrasound on the growth of M. aeruginosa confirmed to contain gas vacuoles and on a laboratory culture with no gas vacuoles was investigated. Both cultures were treated continuously for 9 d with an ultrasonic flow device. To evaluate the influence of ultrasound during the treatment, the chlorophyll-a concentration was measured daily. Furthermore, changes in culture characteristic...

The general histological organization of Hydra is reviewed and electron microscopic observations are presented which bear upon the nature of the mesoglea, the mode of attachment of the contractile processes of the musculo-epithelial cells, and the cytomorphosis of the cnidoblasts. Particular attention is devoted to the changes in form and distribution of the cytoplasmic organelles in the course...

The most common form of neutrophil death, under both physiological and inflammatory conditions, is apoptosis. In this study, we report a novel form of programmed necrotic cell death, associated with cytoplasmic organelle fusion events, that occurs in neutrophils exposed to GM-CSF and other inflammatory cytokines upon ligation of CD44. Strikingly, this type of neutrophil death requires PI3K acti...

The process of expulsion of the nucleus during the transformation of the late erythroblast to reticulocyte is described. Erythroid clones taken from the spleen of lethally irradiated mice transplanted with syngeneic bone marrow were used. 10-12-day old isolated clones were fixed in glutaraldehyde, then in osmium tetroxide. Ultra-thin sections were stained with uranyl acetate and/or lead citrate...