The presence and location of sporopollenin in fruiting bodies of the cellular slime moulds

1984 ◽  
Vol 66 (1) ◽  
pp. 297-308
Author(s):  
Y. Maeda
Keyword(s):  
Cell Membrane ◽  
Biological Significance ◽  
Spore Wall ◽  
Fruiting Bodies ◽  
Fruiting Body Formation ◽  
Body Formation ◽  
Slime Moulds ◽  
Inner Surface ◽  
Cellular Slime ◽  
Cellular Slime Moulds

The presence of an acetolysis-resistant polymer (sporopollenin) in the cellular slime moulds is demonstrated. This polymer is located on the stalk sheath of fruiting bodies as a bundle of fine fibrils (4-5 nm diameter). The location and structure of sporopollenin in spores are shown to vary considerably, depending upon the species. In Polysphondylium violaceum spores, sporopollenin is composed of fine spicules (4-5 nm in diameter, 25–50 nm long) that cover both the outermost layer of spore wall and the inner surface of the cell membrane. The sporopollenin of Dictyostelium discoideum spores is located preferentially close to the inner surface of the cell membrane, forming a mass of electron-opaque fine granules (4-5 nm in diameter). D. mucoroides spores, however, appear not to possess a tight network of sporopollenin, since they were less resistant to acetolysis than those of the other species. The biological significance of the results is discussed with special reference to fruiting body formation.

Participation of the cell surfaces in determining the developmental courses in the cellular slime mould Dictyostelium purpureum

Development ◽  
1978 ◽  
Vol 48 (1) ◽  
pp. 153-160
Author(s):  
M. Saito ◽  
K. Yanagisawa
Keyword(s):  
Fruiting Body ◽  
Developmental Courses ◽  
Fruiting Bodies ◽  
Cell Surfaces ◽  
Fruiting Body Formation ◽  
Con A ◽  
Body Formation ◽  
Dictyostelium Purpureum ◽  
Cellular Slime ◽  
Type Strains

Dictyostelium purpureum S5 and S6, mating type strains, form fruiting-bodies in a monoclonal culture, but produce macrocysts in a mix culture. The effects of Concanavalin A (Con A) on both fruiting-body formation and macrocyst formation, and changes of Con Amediated cell agglutinability during development were studied. It was found that Con A inhibits macrocyst formation but not fruiting-body formation, and that macrocyst-forming cells are much more susceptible to Con A agglutination than are fruiting-body-forming cells during the aggregation stages. When fruiting-body-forming cells are treated with either trypsin or α-chymotrypsin, their Con A agglutinability is enhanced to the same extent as that of macrocyst-forming cells. It was also found that when S6 cells are treated with proteases they sometimes produce normal macrocysts even in a monoclonal culture. The results obtained in these experiments showed that the surface properties of fruitingbody- forming cells and macrocyst-forming cells are different, and that the cell surface might play an important role in determining the two developmental courses.

Cell differentiation during fruiting body formation in polysphondylium pallidum

1979 ◽  
Vol 35 (1) ◽  
pp. 203-215
Author(s):  
D.H. O'Day
Keyword(s):  
Cell Differentiation ◽  
Fruiting Body ◽  
Neutral Red ◽  
Immunofluorescent Staining ◽  
Stalk Cell ◽  
Fruiting Body Formation ◽  
Body Formation ◽  
Polysphondylium Pallidum ◽  
Slime Moulds ◽  
Cellular Slime

The spatial pattern of cellular differentiation was studied during fruiting body formation in Polysphondylium pallidum using 3 different staining methods: Calcofluor fluorescence (cellulose accumulation), neutral red (prestalk cells) and immunofluorescence (prespore cells). Neutral-red staining revealed the existence of a clear prestalk region which becomes evident during aggregation and continues throughout culmination. Immunofluorescent staining demonstrated that cells in the prestalk region gradually lose their presporeness (fluorescence) as they are transformed into differentiated stalk cells. Calcofluor staining revealed that stalk cell differentiation begins during the mid-aggregation phase and that the mode of formation of the main stalk and the side branches differs slightly in morphology. Calcofluor staining also demonstrated the development, during aggregation, of a thick cellulosic girdle with lateral tubular extensions which surround the aggregation streams. The above results are discussed in terms of our present knowledge about differentiation and morphogenesis in cellular slime moulds.

Acrasin, the Chemotactic Agent in Cellular Slime Moulds

1956 ◽  
Vol 33 (4) ◽  
pp. 645-657
Author(s):  
B. M. SHAFFER
Keyword(s):  
Room Temperature ◽  
Dialysis Membrane ◽  
Relay System ◽  
Highly Active ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Set Up ◽  
Cellular Slime Moulds ◽  
Extracellular Slime ◽  
Do So

1. A study has been made of acrasin, the agent inducing chemotaxis in the amoebae of cellular slime moulds. 2. A method has been developed for subjecting sensitive amoebae to a fluctuating gradient set up by an artificial source that can be renewed at intervals of as little as a few seconds with fresh test solution. 3. Amoebae orient to a gradient maintained with the cell-free liquid freshly obtained from the immediate surroundings of a natural source. 4. Acrasin solution as secreted loses its activity very rapidly at room temperature. 5. A highly active stable solid is obtained by drying methanolic culture extracts; it resists boiling and exposure to acids and alkalis. Its solubility decreases rapidly in passing up the alcohol series. 6. The original instability has been shown to be due to the presence of another extracellular slime-mould product, possibly an enzyme; it, unlike acrasin, cannot pass rapidly across a dialysis membrane, is heat labile, and can be precipitated by ammonium sulphate. 7. The advantages of the organism's itself inactivating acrasin are considered. 8. Some of the advantages of a source's releasing acrasin in pulses are discussed; but it is not essential for orientation for it to do so. 9. Sensitive amoebae not only are oriented by an acrasin solution but are caused to secrete acrasin: this is the basis of a chemotactic relay system.

scholarly journals Multicellular Development in Myxococcus xanthus Is Stimulated by Predator-Prey Interactions

2007 ◽  
Vol 189 (15) ◽  
pp. 5675-5682 ◽  
Author(s):  
James E. Berleman ◽  
John R. Kirby
Keyword(s):  
Fruiting Body ◽  
Prey Availability ◽  
Process Analysis ◽  
Myxococcus Xanthus ◽  
Stringent Response ◽  
Fruiting Bodies ◽  
Fruiting Body Formation ◽  
Multicellular Development ◽  
Body Formation ◽  
Body Development

ABSTRACT Myxococcus xanthus is a predatory bacterium that exhibits complex social behavior. The most pronounced behavior is the aggregation of cells into raised fruiting body structures in which cells differentiate into stress-resistant spores. In the laboratory, monocultures of M. xanthus at a very high density will reproducibly induce hundreds of randomly localized fruiting bodies when exposed to low nutrient availability and a solid surface. In this report, we analyze how M. xanthus fruiting body development proceeds in a coculture with suitable prey. Our analysis indicates that when prey bacteria are provided as a nutrient source, fruiting body aggregation is more organized, such that fruiting bodies form specifically after a step-down or loss of prey availability, whereas a step-up in prey availability inhibits fruiting body formation. This localization of aggregates occurs independently of the basal nutrient levels tested, indicating that starvation is not required for this process. Analysis of early developmental signaling relA and asgD mutants indicates that they are capable of forming fruiting body aggregates in the presence of prey, demonstrating that the stringent response and A-signal production are surprisingly not required for the initiation of fruiting behavior. However, these strains are still defective in differentiating to spores. We conclude that fruiting body formation does not occur exclusively in response to starvation and propose an alternative model in which multicellular development is driven by the interactions between M. xanthus cells and their cognate prey.

Vertebrates as vectors of cellular slime moulds in temperate forests

1992 ◽  
Vol 96 (8) ◽  
pp. 670-672 ◽  
Author(s):  
Steven L. Stephenson ◽  
John C. Landolt
Keyword(s):  
Temperate Forests ◽  
Slime Moulds ◽  
Cellular Slime ◽  
Cellular Slime Moulds

Implications of enzyme kinetics

2003 ◽  
Vol 31 (3) ◽  
pp. 719-722 ◽  
Author(s):  
A.G. McDonald
Keyword(s):  
Calcium Concentration ◽  
Calcium Oscillations ◽  
Rate Laws ◽  
Sustained Oscillations ◽  
Slime Moulds ◽  
Cellular Slime ◽  
The Many ◽  
Oxidase Reaction ◽  
Signalling Systems ◽  
Cellular Slime Moulds

Of the many examples of oscillatory kinetic behaviour known, several are briefly reviewed, including those of glycolysis, the peroxidase–oxidase reaction and oscillations in cellular calcium concentration. It is shown that simple mathematical models employing allosteric rate laws are sufficient to explain the instability of the steady state and the appearance of sustained oscillations. The cAMP-signalling systems of cellular slime moulds and the dynamics of intracellular calcium oscillations illustrate the importance of such oscillophores to inter- and intra-cellular communication and differentiation.

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