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The Dictyostelids

The Dictyostelids

With the collaboration of Ann Worley Rahn
Copyright Date: 1984
Pages: 466
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  • Book Info
    The Dictyostelids
    Book Description:

    Kenneth Raper tells how dictyostelids are isolated, cultivated, and conserved in the laboratory; how myxamoebae aggregate to form multicellular pseudoplasmodia; how fructifications arise by transformation of amoeboid cells into stalk cells and spores; and how similar cells can, under certain conditions, enter a sexual phase. For each known dictyostelid Professor Raper includes a complete description and photographic illustrations; one new species is described.

    Originally published in 1984.

    ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

    eISBN: 978-1-4008-5656-5
    Subjects: Biological Sciences

Table of Contents

  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-vi)
    (pp. vii-x)
    Kenneth B. Raper
    (pp. xi-xii)
  5. Part I. Growth and Morphogenesis

    • CHAPTER 1 Historical Background
      (pp. 3-16)

      Slime molds of the dictyostelid type have been known since Oskar Brefeld isolated and describedDictyostelium mucoroidesin 1869. While examining the fungus flora of horse dung he observed spores of the same form but much smaller than those ofMucor mucedo. Unable at first to trace their origin, he fortunately, and soon thereafter, obtained on rabbit dung in relatively clean culture abundant fruiting structures bearing similar spores. Superficially these structures resembled the sporangia and sporangiophores of aMucor, hence the specific name. Several unique features, however, refuted any probable relationship: the “sporangia” had no enveloping walls and the spores...

    • CHAPTER 2 Occurrence and Isolation
      (pp. 17-29)

      The dictyostelid slime molds were long considered to be primarily coprophilous, for it was from the dungs of animals, commonly herbivores, that the early investigators obtained most of their cultures (Brefeld, 1869 and 1884; Nadson, 1889; Olive, 1901 and 1902; Potts, 1902; Pinoy, 1903; and others). Even then it was recognized that other habitats could be involved as well. Van Tieghem foundAcrasis granulatagrowing on a paste of beer yeast (1880),Coenonia denticulataon decaying beans partially covered by water (1884), andDictyostelium lacteumon decomposing agarics (1880). Some decades later, Oehler (1922) recorded compost and forest soil, along...

    • CHAPTER 3 Ecology
      (pp. 30-47)

      It is now well established that the dictyostelids represent a normal component of the microflora of most soils. It is also generally accepted that the numbers and types of dictyostelids present in any particular soil are strongly influenced, if not actually determined, by a variety of environmental and nutritional factors. Of these, ambient temperature, soil moisture, pH, plant cover and available decomposing organic matter, and the amount and character of its bacterial content are very important.

      As early as 1947, B. N. Singh demonstrated in dramatic fashion the interrelationship of two of these factors upon the presence and growth of...

    • CHAPTER 4 Cultivation
      (pp. 48-76)

      Dictyostelids occur naturally in soil and in organic residues undergoing aerobic decomposition, where they grow and survive by feeding upon the bacteria that are present. This would suggest, and laboratory experiments have shown (Raper, 1937; Singh, 1947b), that myxamoebae ofDictyosteliumcan utilize a wide variety of bacteria as food. Experiments have shown also that some types of bacteria are consumed more rapidly and more completely than others. Additionally, the same bacterium on one substrate is often better nutrient for the myxamoebae than when it grows on a different substrate. Taken together, these observations clearly indicate that in the routine...

    • CHAPTER 5 Culture Maintenance
      (pp. 77-86)

      Insofar as is known, all species of the Dictyostelidae can be maintained indefinitely in laboratory culture by periodic transfer onto appropriate agar media with suitable bacterial associates. Such stocks, whether in plates or tubes, should be renewed every 4-6 months, and following growth and fructification should be stored at 3-5°C to reduce evaporation and extend viability. Low-nutrient substrates are generally preferable, and media such as numbers 1, 3, and 4 listed in Chapter 4 are recommended. In our experience hay infusion agar, with or without 0.05 or 0.1% added peptone, has been used most commonly. In recultivating dictyostelid stocks one...

    • CHAPTER 6 Vegetative Stage
      (pp. 87-103)

      The vegetative phase of all cellular slime molds consists of amoeboid cells that feed upon microorganisms smaller than themselves, grow, and by repeated division build up large populations of free-living cells prior to fructification. Among these myxamoebae are cells of different patterns, and in substantial part it is upon such differences that the three subclasses of the Acrasiomycetes are recognized, namely: the Protostelidae, wherein the myxamoebe (and small Plasmodia) have nuclei with compact, centrally positioned nucleoli and filose pseudopodia; the Acrasidae, with nuclei of similar pattern but with broad, lobose pseudopodia; and the Dictyostelidae, characterized by nuclei with peripherally lobed...

    • CHAPTER 7 Cell Aggregation
      (pp. 104-133)

      Of the several features that distinguish the Acrasiomycetes none is more singular or more striking than the phenomenon of cell aggregation that marks the transition from a vegetative stage of independent myxamoebal growth to a fruiting stage of cellular interdependence and divergent differentiation. It is a phenomenon that fascinated Brefeld (1869) despite his early misinterpretation of its significance, and it is the phenomenon that captivated van Tieghem and led him (1880) to select the nameAcrasis¹ for the assemblage of collaborating cells in his culture vessels. That the cells retained their individuality but still built multicellular fructifications of predictable pattern...

    • CHAPTER 8 Fructification
      (pp. 134-177)

      Singular as is the phenomenon of cell aggregation in the dictyostelids, it is but a prelude to the even more remarkable process of fructification, wherein the increasingly interdependent myxamoebae construct multicellular sorocarps and produce the spores necessary for survival. While it is convenient to consider aggregation and fructification as separate developmental stages, as is done here, the reader should remember that they actually represent successive steps in a continuing progression. In fact, sorocarp formation in many species, if not in most, may be initiated well before cell aggregation is complete.

      We also speak of an aggregation as typically producing a...

    • CHAPTER 9 Macrocysts
      (pp. 178-222)

      In addition to the asexual fructifications, or sorocarps, which consist of upright sorophores bearing one or more son, some dictyostelids show an alternative, sexual mode of reproduction—the macrocysts. Although probably seen and illustrated by Brefeld in 1869, these structures were not so designated until the middle of this century (Raper, 1951), and their potential importance in the life cycle of cultures that produce them was not recognized until much later (Clark, Francis, and Eisenberg, 1973; Erdos, Raper, and Vogen, 1973). The history of how this recognition came about is worth recounting.

      In his description ofDictyostelium mucoroides, Brefeld (1869)...

  6. Part II. Systematics

    • CHAPTER 10 Acrasiomycetes
      (pp. 225-241)

      The Acrasiomycetes all have a trophic phase consisting of small, free-living myxamoebae, all show some type of cell aggregation, and all undergo some degree of cellular differentiation incident to fructification. Such differentiation is limited in some cases but substantial in others, and upon this and other bases two subclasses can be recognized. Of these, the Acrasidae (acrasids) represent the less differentiated forms and are presumed to be more primitive, while the Dictyostelidae (dictyostelids) represent more strongly differentiated forms and are considered to be more advanced. Historically, the two have been studied together, sometimes with subtle implications of progressive phylogeny (E....

    • CHAPTER 11 Dictyostelidae
      (pp. 242-245)

      Classification of the Dictyostelidae presents a singular challenge. This results in part from a variety of environmental pressures that influence growth and development, and in part from characteristics of the dictyostelids that are in themselves unique. The latter merit primary consideration, for the systematist is faced not so much with classifying organisms in a true sense as with classifyingcommunitiesof organisms that aggregate, integrate, and differentiate in reasonably constant ways. The separation of growth and morphogenesis in these slime molds cannot be overemphasized. Unlike the situation in higher plants and hyphal fungi, where the two processes proceed simultaneously, in...

    • CHAPTER 12 Dictyosteliaceae: Dictyostelium
      (pp. 246-367)

      DictyosteliumBrefeld, in Abh. Senckenberg. Naturforsch. Ges.7: 85-107, Tafs. I-III, figs. 1-36 (1869), and in Untersuch. Gesammtgeb. Mykologie6: 1-34 (1884). Also Olive (E. W.), in Proc. Amer. Acad. Arts and Sci. 37: 338-341 (1901), and in Proc. Boston Soc. Natur. Hist.30: 451-513, 68 figs., in pis. 6-8(1902).

      Vegetative stage consists of small uninucleate, free-living amoeboid cells that feed upon bacteria; fruiting stage characterized by the coordinated aggregation of these myxamoebe into pseudoplasmodia, and the subsequent development from them of erect, semi-erect, or partially prostrate sorocarps with cellular sorophores bearing unwalled sori; sorophores unbranched or with branching patternless...

    • CHAPTER 13 Dictyosteliaceae: Polysphondyliun
      (pp. 368-392)

      PolysphondyliumBrefeld, in Unters. Gesammtgeb. Mykol.6: 1-34, Taf. I & II, figs. 1-35 (1884). Also Olive (E. W.), in Proc. Amer. Acad. Arts Sci.37: 341-342 (1901) and Proc. Boston Soc. Natur. Hist.30: 451-513, pls. 6-8 (1902); Harper, in Bull. Torrey Bot. Club56: 227-258, figs. 1-44 (1929), and ibid.59: 49-84 (1932).

      Vegetative stage consisting of free-living, independent myxamoebae which feed upon bacterial cells; fruiting stage characterized by the aggregation of these myxamoebae into pseudoplasmodia and the subsequent development from them of branched sorocarps with cellular stalks that, in the main, bear globose sori terminally and at the...

    • CHAPTER 14 Acytosteliaceae: Acytostelium
      (pp. 393-407)

      AcytosteliumRaper, in Mycologia48: 179, figs. 4 & 6 (1956).

      Vegetative stage consisting of free-living, independent myxamoebae which feed upon bacterial cells; fruiting stage characterized by the aggregation of these cells to form radiate pseudoplasmodia of varying dimensions and the subsequent development from these of sorocarps composed of very thin acellular sorophores bearing masses of spores as terminal sori.

      Acytosteliumis the most recently described genus of the Dictyostelidae and differs from the older genera in several ways, particularly in the acellular nature of its sorophores. It is at the same time relatively rare in nature and is characterized by...

    • CHAPTER 15 Coenonia
      (pp. 408-412)

      Coenonia denticulatawas described by Ph. van Tieghem in 1884, and from his written account it must have produced more highly specialized fruiting structures than any cellular slime mold presently known. As was true ofAcrasis granulata, which he described four years earlier,Coenoniawas not illustrated; and like that species also, it has not been rediscovered. Thus we are left with van Tieghem’s brief report as the sole record of a very remarkable slime mold—one that is thought to represent a dictyostelid. What follows, therefore, represents a condensation of his original statement, for we cannot do better than...

    (pp. 413-416)

    In ending this monograph on the dictyostelids, it is perhaps well to look again at some of the striking adaptations encountered among these slime molds and to consider how they redound to the organism’s advantage, and to that of an investigator as well. Cell aggregation coupled with ensuing morphogenesis certainly enables the myxamoebae to achieve ends that are impossible to attain as independent, unprotected cells; and the disposition ofDictyostelium purpureumand other long-stalked forms to build sorocarps toward a weak source of light, a minimal increase in temperature, or a more open area with slightly reduced humidity must be...

    (pp. 417-442)
  9. INDEX
    (pp. 443-453)
  10. Back Matter
    (pp. 454-454)