3.25 in. x 4 in. Lantern Slides, Original Magnification: x13,750, and The authors took advantage of the fact that rats gavage-fed a large bolus of ethanol (single malt I hope) were observed to have their Golgi cisternae loaded with LDL particles. Since LDL particles are lighter than most other intracellular organelles, following homogenization of ethanol-fed rats, the Golgi fractions "floated" to the top of denser sucrose gradients during centrifugation. This allowed investigators to analyze the membrane properties of "pure" Golgi fractions and set the stage for development of fusion assays that led to an understanding of factors regulating the specificity of membrane fusion - the SNARE hypothesis.
3.25 in. x 4 in. Lantern Slides, Original Magnification: x54,000, and Rough microsomes, the cell fractionation equivalent of the rough ER in intact cells, were extensively used to determine the mechanism of translocation of newly synthesized exportable proteins across the ER membrane. The culmination of these studies on rough microsomes was the elucidation of the "Signal Hypothesis".
3.25 in. x 4 in. Lantern Slides, Cell fractionation confirmed that newly synthesized acinar cell secretory proteins moved from the RER to the periphery of the Golgi in the lumen of a smooth-surfaced membrane bounded compartment. This paper also describes the pancreatic slice system and the pulse-chase protocol used to label newly synthesized secretory proteins with radioactive leucine. The micrograph shows smooth microsomes obtained from the top band in the photograph of sucrose density gradient., and Original Magnification: x10,000
3.25 in. x 4 in. Lantern Slides, Dr. V. T. Marchesi from Yale and colleagues took advantage of the high purity of red cell ghosts obtained by hypotonic lysis to analyze the properties of membrane proteins. They identified spectrin (from the Latin specere, to look at - or ghost) as a major red cell membrane cytoskeletal protein responsible for maintaining the biconcave shape of red cells. In hereditary spherocytosis, spectrin is mutated resulting in anemias due to greater fragility of red cells which cannot assume a biconcave shape., and Original Magnification: x25,000
