Showing papers by "Lindsay S. Olive published in 1971"
TL;DR: A new genus and species of the Protosteliida (Mycetozoa) was isolated from dead plant material- Ceratiomyxella tahitiensis from Tahiti and var.
Abstract: A B S T R A C T A new genus and species of the Protosteliida (Mycetozoa), Ceratiomyxella tahitiensis, was isolated from dead plant material-var. tahitiensis from Tahiti and var. neotropicalis from Brazil and Colombia. The sporocarps have deciduous spores borne singly on slender hollow stalks; zooeysts with anteriorly flagellate planonts are produced. The trophic stage is comprised of uninucleate to plurinucleate amoeboid cells and reticulate plasmodia; the uninucleate cells become flagellate in water. The prespore cells and spores are plurinucleate. Sexuality has not been demonstrated. Var. tahitiensis has globose spores and produces its zooeysts just after spore germination, whereas var. neotropicalis has subglobose spores and forms zooeysts later in the life cycle. The species is thought to show phylogenetic relationships with Ceratiomyxa, which was recently transferred to the Protosteliida by Olive. THE PROTOSTELIDS, or Protosteliida, constitute the subclass Protostelia of the Mycetozoa (Olive, 1970). They are a common and widespread group of primitive mycetozoans, which are thought to be ancestral to both the dictyostelids of the cellular slime molds and the myxomycetes. Of the isolates in our laboratory which have remained undescribed, two similar ones from the tropicsone from Tahiti and the other from Brazil-have proved of particular interest from the standpoint of their possible relationship to Ceratiomyxa. The latter genus, formerly included in the myxomycetes, has recently been transferred to the Protosteliida under the family name Ceratiomyxidae (Olive, 1970). The two isolates are described here as varieties of a new genus and species, which has a number of characteristics indicating phylogenetic affinities with Ceratiomyxa. We have just recently obtained a third isolate from Colombia which resembles the one from Brazil, but it has not been studied in any detail and will not be included in the following discussion.
15 citations
TL;DR: The discovery of synaptonemal complexes at the time of cleavage of prespore cells demonstrates that meiotic pairing begins before development of the sporocarp is under way, the chromosomes presumably remaining paired until the two successive meiotic nuclear divisions occur in the spore.
Abstract: On the basis of similarities in sporogenesis and plasmodial characteristics, Ceratiomyxa was recently transferred from the myxomycetes to the protostelids (Olive, 1970). Several earlier reports have claimed the occurrence of sexuality, with meiosis taking place in the spores, in C. fruticulosa (Mull.) Macbride (e.g., E. W. Olive, 1907; Gilbert, 1935; Wilson and Ross, 1955; Sansome and Dixon, 1965), but further confirmation has been needed. The present study was undertaken to determine whether synaptonemal complexes, the indicators of meiotic chromosomal pairing (Moses, 1968), are present in the nuclei that enter the spores. Developing spore columns of C. fruticulosa were collected from nature and fixed with sequential glutaraldehyde-0s04 and processed further as described by Furtado and Olive (1970) for other protostelids. Difficulties in obtaining good fixation of desired stages were encountered as a result of the inability thus far to culture the organism in the laboratory and because of the large amount of mucilaginous material surrounding the protoplasts. In spite of these problems, a number of nuclei in plasmodia undergoing segmentation into prespore cells (FIGS. 1-3) and in the prespore cells themselves (FIG. 4) were found to contain structures showing the basic characteristics of synnaptonemal complexes. The discovery of synaptonemal complexes at the time of cleavage of prespore cells demonstrates that meiotic pairing begins before development of the sporocarp is under way, the chromosomes presumably remaining paired until the two successive meiotic nuclear divisions occur in the spore. A third, mitotic division occurs after spore germination, and the 8-nucleate protoplast divides into eight flagellate cells
12 citations
TL;DR: Echinostelium lunatur, a new species discovered in Puerto Rico and North Carolina, is the smallest known myxomycete and there are indications that it may have evolved from a protostelid such as Cavostelius bisporum.
Abstract: Echinostelium lunatur, a new species discovered in Puerto Rico and North Carolina, is the smallest known myxomycete. It produces typical flagellate cells, 2-6-nucleate protoplasmodia, and minute stalked sporangia that contain a lunate structure at the apex of the stalk and (1-)4-8(-14) spores. There is no capillitium. No evidence of sexuality has been observed. The phylogenetic significance of the new species is discussed. There are indications that it may have evolved from a protostelid such as Cavostelium bisporum.
11 citations
TL;DR: A new family, the Endemosarcidae, one new genus, Endemoarca, and two new species are described to accommodate two recently discovered plasmodial organisms with anteriorly biflagellate zoospores and aerial exit tubes.
Abstract: A new family, the Endemosarcidae, one new genus, Endemosarca, and two new species are described to accommodate two recently discovered plasmodial organisms with anteriorly biflagellate zoospores an...
4 citations