Speculations Based on the Morphology of the Golgi Systems in Several Types of Protein-Secreting Cells

Abstract

Electron microscopical observations on the relationship of the Golgi region to other intracellular organelles in certain protein-secreting cells have substantiated and extended existing hypotheses. In micrographs of several cell types, the juxtanuclear Golgi regions were observed to be closely associated with nuclear "pores." The "transition elements" of the ergastoplasmic membranes possess "blebs" which may represent a transport process facilitating the movement of intracisternal contents into the Golgi zone. A "blebbing" process of this nature may be one source of the small variety of Golgi vesicles. Zymogen granules of different densities were observed and their significance was postulated. Light Golgi vacuoles were observed. It is suggested that these vacuoles represent accumulations of relatively fluid material segregated from the secretory product in these cell types. These hypotheses from inferential evidence are discussed and extended.

Cyclic Changes of the Golgi Body during Microsporogenesis in <i>Tradescantia paluclosa</i>

“…These Golgi bodies are composed of decreased number of cisternae, suggesting that the degenera tion of the organelle is brought about by pinching-off of vesicles from the cisternae. Although we could not find any connection of the Golgi-cisternae with the endoplasmic reticulum in the present observation, substances may be transmitted by some way to the Golgi body from the endoplasmic reticulum (Essner and Novikoff 1962, Zeigel and Dalton 1962, Kajikawa 1963. It has been demonstrated that these vesicles which are pinched off from the Golgi cisternae contain the substances accumulated by this organelle (Mollenhauer et al 1961, Sano 1962, Whaley and Mollenhauer 1963, Mollenhauer and Whaley 1963.…”

Behavior of Membrane System in the Cell during Cell Divisions of Microsporogenesis in <i>Tradescantia paludosa</i>

“…. It is assumed that vesicles of the endoplasmic reticulum are absorbed into the cisternae of the Golgi body with their surrounding membranes , Zeigel and Dalton 1962. As discussed in the preceding pages, the Golgi body seems to arise from the vesicles that are present in the cytoplasm of microspore immediately after meiosis.…”

Intracellular membrane flow: reconstitution of transition vesicle formation and function in a cell-free system.

“…Transfer of membrane materials from endoplasmic reticulum to Golgi apparatus long has been considered from morphological evidence to be mediated by transition vesicles that bleb off specialized, part-rough, part-smooth regions of the endoplasmic reticulum (1,2). These vesicles, covered by a nap-like coat material not containing clathrin (3)(4)(5), are thought to coalesce to form new Golgi apparatus cisternae or to fuse with existing Golgi apparatus membranes to effect delivery to the Golgi apparatus of materials derived from the endoplasmic reticulum (6).…”

“…1A). These vesicles have been postulated to migrate to the Golgi apparatus and there to coalesce to form new Golgi apparatus cisternae (1,2). The transition vesicles are distinguished from the more familiar clathrin-coated vesicles of the trans Golgi apparatus face by the nap-like rather than "spiny" appearance of their surfaces (Fig.…”