Amoeboid

Cobbold, P. H. (1980). Cytoplasmic free calcium and amoeboid movement. Nature 285 441 146. 

HOlsmann, N., Haberey, M. (1973). Phenomena of amoeboid movement. Behavior of the cell surface in Hyalodiscus simplex. (Wohifarth-Bottermann). Acta Protozoologica 7, 71-82. 

Komnick, H., Stockem, W., Wohlfarth-Botterman, K.E. (1973). Cell motility Mechanisms in protoplasmic streaming and amoeboid movement. Int. Rev. Cytol. 34, 169-249. 

Maciver, S.K, (1987). Cytoskeletal Organization in Amoeboid Locomotion. Ph.D thesis. University College, London. 

My hypothesis otherwise remains what it was in 1993 - the epithelial component originated from an epithelial animal and the amoeboid component originated from an amoeboid animal equipped with a protocnidocysts, and possibly already living as an intracellular parasite on the epithelial animal during some stage of its life cycle. One or another device for cell fusion would have to be invoked to explain how an amoeba and an epithelium... 

This hypothesis would seem testable in a number of ways, one of which I am working on currently. Basically, since epithelial tissue and muscle fibers are present in Placozoa and in the epithelial component of Cnidaria, the specific proteins of epithelia and muscle should show more similarities to each other than to nerve which is absent in Placozoa and derived from amoeboid cells in Cnidaria. My students and I are attempting to test this hypothesis on a broad scale (not confined to Cnidaria) by looking at similarities among tissue-specific proteins in general. The question is Do sequences in proteins identified with epithelia and muscle show more similarities with each other than they do with sequences of specific proteins for other tissues . 

Ling, E. A. and Wong, W. C. The origin and nature of ramified and amoeboid microglia an historical review and current concepts. Glia 7 84-92,1993. 

Most amoeboid protozoa assimilate particles by invagination of the plasma membrane in an actin-based phagocytotic process and digest them in food... 

Protists Eukaryotic microorganisms that are neither animal, fungi, plant, or archaean. Unicellular forms include the amoeboid protozoans and algae, such as the foraminferans and radiolarians, and dinoflagellates and diatoms, respectively. Some algae are either multicellular or colonial, such as the red algae and freshwater Volvox, respectively. 

Radiolaria A group of amoeboid protozoans that deposit siliceous tests. 

All eucaryotic cells contain various proteins in their cytoplasm that interact to form mechanically stabilizing structures. The amounts of these proteins differ with cell type, and the structural elements - collectively referred to as the cytoskeleton -can be very labile. Labile transformations of cytoskeletal networks are involved in such essential biological phenomena as chromosome movement and cell division, intracellular material transport, shape changes relating to tissue development, and amoeboid-like locomotion (1-3). A great deal of work in recent years has led to the biochemical characterization of numerous cytoskeletal proteins(A) and the elucidation of their spatial localization within a cell(2). However, few quantifiable models yet exist that are appropriate for incorporating that information into notions of shape transformation and cell movement(5-8). 

Mesenchymal-amoeboid transition in motiHty with MMPi treatment... 

Wolf K, Mazo I, Leung H et al (2003) Compensation mechanism in tumor cell migration mesenchymal-amoeboid transition after blocking of pericellular proteolysis. J Cell Biol 160 267-277... 

The amoeboid descriptor for amoeboid olivine aggregates refers to their irregular shapes. AOAs tend to be fine-grained and porous, and have comparable sizes to CAIs in the same meteorite. They consist mostly of forsterite and lesser amounts of iron-nickel metal, with a refractory component composed of anorthite, spinel, aluminum-rich diopside, and rarely melilite. The refractory component is sometimes recognizable as a CAI embedded within the AOA. The AOAs show no evidence of having been melted, but some contain CAIs that have melted. 

Sugiura, N. and Krot, A.N. (2007) 26Al-26Mg systematics of Ca-Al-rich inclusions, amoeboid olivine aggregates and chondrules form the ungrouped carbonaceous chondrite Acfer 094. Meteoritics and Planetary Science, 42, 1183-1195. 

The 1980 view assumed that the prokaryote-to-eukaryote transition occurred via gradualist mechanisms such as point mutation and hence did not involve symbiosis at all (van Valen and Maiorana 1980 Doolittle 1980) and culminated with a cell that possessed a nucleus, but lacked mitochondria. This is what Doolittle (1998) has called the standard model . In this view, mitochondria are interpreted as a small tack-on to, and mechanistically unrelated to, the process that made eukaryotic cells nucleated and complex (Cavalier-Smith 2002). In the standard model, mitochondria (and chloro-plasts) are descended from endosymbionts, but the nuts-and-bolts of the prokaryote-to-eukaryote transition (the origin of eukaryote-specific traits) was seen as having occurred independently from, and prior to, the origin of mitochondria. The paper by van Valen and Maiorana (1980) expresses this view in clear physiological terms the host was assumed to be an amoeboid, anaerobic, fermenting cell related to archaebacteria, the advantage of the mitochondrial endosymbiont was to supply ATP. 

Tan TC, Suresh KG (2006) Amoeboid form of Blastocystis hominis—a detailed ultrastruc-tural insight. Parasitol Res 99 737-742... 

In many cells that respond to extracellular signals, Ca2+ serves as a second messenger that triggers intracellular responses, such as exocytosis in neurons and endocrine cells, contraction in muscle, and cytoslceletal rearrangement during amoeboid movement. Normally, cytosolic [Ca2+] is kept very low (<10-7 m) by the action of Ca2+ pumps in the ER, mitochondria, and plasma membrane. Hormonal, neural, or other stimuli cause either an influx of Ca2+ into the cell through specific... 

Unicellular saprophytic plants without chlorophyll, having a plasmodium stage of fused cells, mostly amoeboid in... 

Cells naked at maturity, i.e. cells not producing cell walls upon entering the host cell zoospores amoeboid or with an anterior flagellum. 

Holocarpic thallus at first naked and amoeboid microscopic fungi parasitic on water and land plants.Order Myxochytridiales (Chytridiales)... 

A Mostly freshwater forms without central capsule reproduction either by equal division or by biflagellate spores one or more nuclei contractile vacuole in freshwater forms with little power of amoeboid movement, either with or without silicious skeleton... 

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