Biomaterial Database

Response of Dictyostelium plasma membranes to adenosine 3':5'-cyclic monophosphate. 1973

J H Gregg, and M G Nesom

Myxamoebae of the cellular slime mold Dicytostelium discoideum aggregate in response to a chemotactic substance identified as adenosine 3':5'-cyclic monophosphate. Upon aggregation cell division is suppressed, the cells become adhesive, and differentiation is initiated. Freeze-fracture studies of myxamoebae were conducted to determine the effect of cyclic AMP and calcium on plasma membrane ultrastructure. The inner surfaces of the plasma membranes exhibited particulate structures whose sizes (43-187 A) and frequency distribution were determined. Cyclic AMP and calcium induced within 2 hr the formation of particles having average diameters 1.7-times and 1.5-times greater, respectively, than those of the vegetative myxamoebae controls. These data suggest that cyclic AMP mobilizes the intracellular calcium which may be effective in changing plasma membrane structure.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009235	Myxomycetes	A division of organisms that exist vegetatively as complex mobile plasmodia, reproduce by means of spores, and have complex life cycles. They are now classed as protozoa but formerly were considered fungi.	Myxomycota,Protosteliomycetes,Slime Molds, Plasmodial,Slime Molds, True,Mold, Plasmodial Slime,Mold, True Slime,Molds, Plasmodial Slime,Molds, True Slime,Myxomycete,Myxomycotas,Plasmodial Slime Mold,Plasmodial Slime Molds,Protosteliomycete,Slime Mold, Plasmodial,Slime Mold, True,True Slime Mold,True Slime Molds
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D005613	Freeze Etching	A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.	Etching, Freeze
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor