Cellular differentiation and pattern formation in the absence of morphogenesis in the cellular slime mould Polysphondylium pallidum: evidence for a biochemical tip (organizer) in submerged aggregates

1981 ◽  
Vol 27 (9) ◽  
pp. 924-936 ◽  
Author(s):  
Gary D. Paterno ◽  
Danton H. O'Day

When amoebae of Polysphondylium pallidum WS320 are placed in nonnutrient buffer in roller tube culture they form spherical or ellipsoidal aggregates. At first the aggregates demonstrate a "loose" morphology but by 12 h, with the formation of a cellulose-containing, peripheral sheath, they become "tight" aggregates. At this time stalk differentiation begins. Using various methods for the resolution of prespore (ultrastructure, spore antigen immunofluorescence, periodic acid – Schiff staining) and prestalk (ultrastructure, alkaline phosphatase histochemistry, neutral red staining, Calcofluor fluorescence) cell localization, the pattern of cell differentiation in submerged aggregates was shown to be essentially identical to that of normal pseudoplasmodia. Furthermore, using a cAMP bioassay it was revealed that the submerged aggregates, while devoid of a morphological tip, do possess a biochemical tip which is correlated with sites of neutral red staining and stalk cell differentiation. As a result of these studies, an earlier argument that the tip of the pseudoplasmodium is not essential for the establishment of pattern or in the "organization" of cellular differentiation during slime mould development is contradicted.

1979 ◽  
Vol 35 (1) ◽  
pp. 203-215
Author(s):  
D.H. O'Day

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.


Development ◽  
1978 ◽  
Vol 47 (1) ◽  
pp. 195-206
Author(s):  
Danton H. O'Day ◽  
Antony J. Durston

Colchicine is shown to have several effects on the development of the pseudoplasmodia of the cellular slime mould Dictyostelium discoideum At concentrations of 0·01 M and above culmination was prevented, while differentiation of cells into stalk cells occurred at the rear of cell masses. Essentially all cells transformed into stalk cells when slugs were left on colchicine agar for a long time. At concentrations of 0·01 M normal slug architecture was maintained while above 0·025 M pseudoplasmodia reorganized into multiple mounds. Each of these mounds developed an apparently normal discrete tip which was devoid of prespore cells as shown by immunofluorescent staining. The same effects were observed in growing cultures and in regulating slugs treated with colchicine. The data are consistent with the ideas that microtubules are involved in the maintenance of slug architecture and in the differentiation of stalk cells. The modes by which these intracellular structures may operate in these functions are discussed.


1982 ◽  
Vol 28 (10) ◽  
pp. 1143-1149
Author(s):  
Gary D. Paterno ◽  
Danton H. O'Day

Submerged cultures of wild-type Polysphondylium pallidum (WS320) undergo a developmental sequence in which cells agglutinate and form tight aggregates within which extensive stalk and some spore differentiation occurs. Development of submerged cultures of P. pallidum bears many similarities to fruiting body cultures except that differentiation occurs in the absence of morphogenesis. Here we extend the results of an earlier study of submerged cultures of P. pallidum WS320 (Paterno and O'Day. 1981. Can. J. Microbiol. 27: 924–936) by showing that these cultures respond to several exogenous agents (cyclic AMP, lithium chloride, ammonium chloride, colchicine, and concanavalin A) in the same way as slime mould fruiting body cultures. However, two mutants abnormal in cyclic AMP production which complement to form fruiting bodies on agar plates could not form normal submerged culture aggregates when mixed together. Complementation tests with mutant and wild-type cells also failed. The inability of the mutants (PN507 and PN518) to complement in submerged cultures suggests that their fruiting complementarity may be based on a morphogenetic event. A low molecular weight fraction from wild-type cells could enhance development and stalk cell differentiation in WS320 and one mutant, PN507, but not in PN518. Together these data reveal that submerged cultures can be utilized to test the effects of extracellular factors on development and used as a source for the isolation of factors that regulate cellular differentiation.


1988 ◽  
Vol 249 (3) ◽  
pp. 903-906 ◽  
Author(s):  
H R Morris ◽  
M S Masento ◽  
G W Taylor ◽  
K A Jermyn ◽  
R R Kay

Two endogenous differentiation-inducing factors (DIF-2 and DIF-3), which induce stalk-cell differentiation in the cellular slime mould Dictyostelium discoideum, have been identified as the pentan-1-one and monochloro analogues respectively of (1-[(3,5-dichloro-2,6-dihydroxy-4-methoxy)phenyl]hexan-1-one). These compounds represent a new chemical class of effector molecules.


1970 ◽  
Vol 119 (2) ◽  
pp. 171-174 ◽  
Author(s):  
D. J. Watts ◽  
J. M. Ashworth

1. A simple axenic medium suitable for the growth of the myxamoebae of a strain of the cellular slime mould Dictyostelium discoideum is described. 2. Procedures suitable for the growth of this strain in liquid and on solid media are described. 3. Conditions suitable for initiating the cell differentiation of myxamoebae grown axenically are described.


1984 ◽  
Vol 69 (1) ◽  
pp. 159-165
Author(s):  
M. Maeda

The effects of low temperature on morphogenesis and cellular differentiation of Dictyostelium discoideum were examined. During incubation at 5 degrees C, the vegetative and preaggregation cells never developed, but cell masses at the aggregation or slug stage developed to form hemispherical, or dumbbell-shaped multicellular structures. By staining with FITC-antispore IgG, the structures formed after 10 days of incubation of tipped aggregates at 5 degrees C were found to be composed of 90% spores, 5% prespore cells and 5% non-stained cells. Since only 20% of the total cells constituting the tipped aggregate had been prespore cells at the beginning of incubation, this showed that spore differentiation proceeded even at low temperature, while stalk differentiation was completely inhibited. Similar results were obtained when the cells were incubated at 3 degrees C. However, at 0 degree C, morphogenesis and cellular differentiation did not occur, although most of the prespore cells at the late culmination stage differentiated incompletely into spores. Possible reasons for the high proportion of spores being induced by low temperature are discussed.


Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 323-333
Author(s):  
J.G. McNally ◽  
E.C. Cox

Whorls of the cellular slime mould Polysphondylium pallidum originate as spherical cell masses that during normal morphogenesis produce tips only at equidistant positions around their equator. We have observed a series of new patterns in whorls that differ from normal whorls only in that they are larger or more elongated. Among the novel patterns found were arrays of tips distributed fairly regularly over the whole whorl surface, as well as striped patterns detected at earlier stages with a tip-specific antigen. These altered patterns demonstrate that a whorl's size and shape are by themselves important factors in pattern determination. We have compared the range of observed patterns to those predicted by a variety of different theories. We find that while no one theory can account in detail for all of our observations, predictions based on Turing's scheme of pattern formation come the closest.


1987 ◽  
Vol 65 (6) ◽  
pp. 1445-1453 ◽  
Author(s):  
M. Samuel Cannon ◽  
H. W. Sampson ◽  
E. D. Kapes

Blood leukocytes of Bufo marinus were studied by light and phase-contrast microscopy and histochemical techniques for the localization of glycogen, lipids, several basic proteins, and a number of hydrolytic and oxidative enzymes. The hydrolytic enzymes occurred in varying amounts in neutrophils, eosinophils, lymphocytes, and monocytes; neutrophils were the only leukocytes to demonstrate alkaline phosphatase activity, while β-glucuronidase was only seen in lymphocytes, and aryl-sulfatase was not observed in any leukocytes. Periodic acid – Schiff (PAS) positive granules also occurred in varying amounts in leukocytes. Slight lipid activity was only seen in neutrophils, while arginine, and (or) lysine, and tyrosine reactivity was only observed in eosinophils. The appearance and histochemical reactivity of acid phosphatase granules in neutrophils corresponded closely with the appearance and number of specific neutrophilic granules seen in Wright–Giemsa preparations and with the PAS-positive granules. Small lymphocytes were myeloperoxidase (peroxidase) negative; β-glucuronidase, acid phosphatase, and PAS-positive granules corresponded to neutral red granules seen in supravital films. The oxidative enzymes also occurred in differing amounts in leukocytes, but strongly suggested that the leukocytes of Bufo marinus are capable of some degree of aerobic and anaerobic metabolism.


1972 ◽  
Vol 126 (3) ◽  
pp. 609-615 ◽  
Author(s):  
J. Quance ◽  
J. M. Ashworth

1. Myxamoebae of the cellular slime mould Dictyostelium discoideum Ax-2 were grown on different media, and were harvested either in the stationary or exponential phases of the growth cycle to yield samples of myxamoebae differing in enzymic composition. 2. Morphogenesis and cell differentiation phenomena in D. discoideum appear to be similar in myxamoebae grown and harvested under different conditions. 3. The specific activity of the enzymes β-N-acetylglucosaminidase, acid phosphatase, α-mannosidase, β-glucosidase and alkaline phosphatase have been determined during cell differentiation of myxamoebae grown and harvested under different conditions. 4. The pattern of synthesis of these enzymes, all of which have been claimed to be part of the ‘developmental programme’, either remains unaffected despite the origin of the myxamoebae (alkaline phosphatase) or is qualitatively similar but quantitatively affected (acid phosphatase, β-glucosidase) or is both qualitatively and quantitatively affected by changes in the myxamoebae (α-mannosidase, β-N-acetylglucosaminidase). 5. The implications of these results for the concept of a ‘developmental programme‘ are discussed.


Sign in / Sign up

Export Citation Format

Share Document