Side effects of Ricinus lectin (RCA 120) on nucleic acid synthesis in chick embryo fibroblasts

When fibroblasts from chick embryos were treated with Ricinus lectin, the effects observed depended on the stage of development of the embryo from which the cells were prepared. Thus, in 16-day fibroblasts, which have a weak proliferative capacity, nucleic acid synthesis was less sensitive to the effect of this lectin than that in 8-day fibroblasts, whose proliferative capacity is high.     

Purification of the vascular plasminogen activator]

We have isolated a purified preparation of the vascular plasminogen activator. Plasma obtained from post occlusion venous blood has been chromatographed with low and high ionic strength buffers. The purified protein has a relative molecular weight of 71,000.     

Electron microscopic study of secretion of chylomicrons in the rat by enterocytes in lymphatic capillary lumen]

Rats were fed on a 20% fat diet; 30 min. or 2 hrs later intestinal jejunal cells were fixed in situ; samples were taken and processed for subsequent study by electron microscopy. Chylomicron secretion was followed from the enterocyte to the lymphatic capillary lumen. Chylomicrons entered the lamina propria through breaks in the basal membrane at intercellular space level. Their penetration into the lymphatic capillary lumen occurred through the open junctions of the endothelial cells normally kept closed by desmosomal formations.     

Comparison of the effects of concanavalin A on cell growth and the transport of 3-O-methylglucose in chick embryo fibroblasts

The proliferative capacity of Chick embryo fibroblasts was modified by Con A treatment. Con A decreased the growth of fibroblasts from young embryos (8 days), whereas the lectin stimulated the growth of fibroblasts from older embryos (16 days). This differential effect of Con A did not result from changes in cellular permeability to thymidine, but rather from Con A induced modifications of hexose transport. Changes in hexose transport would cause, as a response, parallel modifications in glycolysis and hence energy charge, which would alter proliferative capacity.     

Soil algae of cryptogamic crusts from the Uintah Basin, Utah, U.S.A.

The algal flora of selected soils in the Uintah Basin, Uintah County, Utah, was studied. A total of 45 species was identified from the top soils of three different vascular plant habitats. The soil algal flora was dominated in biomass by filamentous Cyanophyta, including Microcoleus vaginatus, Phormidium minnesotense, and three species of Nostoc . These algae formed the algal matrix of the soil within which other Cyanophyta as well as Chlorophyta, Bacillariophyta, and Euglenophyta occurred.