Clonal Diversity in Populations of Polysphondylium Pallidum, A Cellular Slime Mold

Ketcham, Robert B.; Eisenberg, Robert M.

doi:10.2307/1938201

Cited by 8 publications

(4 citation statements)

References 34 publications

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“…Samples 76-105 were collected at scattered points within 1500 m of this site. All samples were separated by a minimum distance of 1 m. Soil samples were collected in plastic cups, returned to the laboratory and processed as described by Ketcham & Eisenberg (1989). The procedure involved plating soil extract on non-nutrient agar plates coated with bacteria.…”

Section: Collectionmentioning

confidence: 99%

Genetic structure of a natural population of Dictyostelium discoideum, a cellular slime mould

Francis

Eisenberg

1993

Molecular Ecology

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Dictyostelium discoideum is a eukaryotic microbe feeding on soil bacteria. A first step towards describing the genetic structure of populations of this species was made by examining multiple isolates from a single locale. The isolates were grown clonally and their RFLP patterns compared, using a probe specific for a family of tRNA genes. Thirty-nine types were distinguished in 54 isolates. To determine if genetic exchange occurs among members of the population, an analysis of linkage disequilibrium was performed on the RFLP data. Little disequilibrium was found, implying gene flow in the population. In conflict with this result is the finding that no recombinant progeny were recovered from many attempted crosses between pairs of isolates. The tentative conclusion is that genetic exchange does not in fact occur, and that the observed shuffling of RFLP bands is caused by insertion and excision of transposons known to be associated with the tRNA genes of Dictyostelium.

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Section: Collectionmentioning

confidence: 99%

Genetic structure of a natural population of Dictyostelium discoideum, a cellular slime mould

Francis

Eisenberg

1993

Molecular Ecology

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“…Given their global distribution, it is not surprising that dictyostelids can feed on a wide range of bacteria (Raper 1937; Raper and Smith 1939). Food “preferences” and competitive advantages amongst dictyostelid isolates have been observed (Eisenberg et al 1989; Horn 1971; Ketcham et al 1988; Ketcham and Eisenberg 1989). Experiments profiling gene expression during D. discoideum feeding on Gram positive or Gram negative bacteria suggest prey and predators communicate with each other using chemical cues (Carilla-Latorre et al 2008; Nasser et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Multiple Dictyostelid Species Destroy Biofilms of Klebsiella oxytoca and Other Gram Negative Species

Sanders

Borys

Kisa

et al. 2017

Protist

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Dictyostelids are free-living phagocytes that feed on bacteria in diverse habitats. When bacterial prey is in short supply or depleted, they undergo multicellular development culminating in the formation of dormant spores. In this work, we tested isolates representing four dictyostelid species from two genera (Dictyostelium and Polysphondylium) for the potential to feed on biofilms preformed on glass and polycarbonate surfaces. The abilities of dictyostelids were monitored for three hallmarks of activity: 1) spore germination on biofilms, 2) predation on biofilm enmeshed bacteria by phagocytic cells and 3) characteristic stages of multicellular development (streaming and fructification). We found that all dictyostelid isolates tested could feed on biofilm enmeshed bacteria produced by human and plant pathogens: Klebsiella oxytoca, Pseudomonas aeruginosa, Pseudomonas syringae, Erwinia amylovora 1189 (biofilm former) and E. amylovora 1189 Δams (biofilm deficient mutant). However, when dictyostelids were fed planktonic E. amylovora Δams the bacterial cells exhibited an increased susceptibility to predation by one of the two dictyostelid strains they were tested against. Taken together, the qualitative and quantitative data presented here suggest that dictyostelids have preferences in bacterial prey which affects their efficiency of feeding on bacterial biofilms.

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“…Intraspecific trait variation has been found in phytoplankton (Brand, ), Acanthamoeba polyphaga (Jacobson & Band ), Polysphondylium pallidum (also a CSM, now renamed Heterostelium pallidum; Ketcham & Eisenberg, ), and D. giganteum (Sathe et al, ). For all we know, every soil microbe may provide an example.…”

Section: Interstrain Differences and Neutral Phenotypesmentioning

confidence: 99%

Many roads lead to Rome: Neutral phenotypes in microorganisms

Nanjundiah

2019

J Exp Zool Pt B

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John Bonner pointed out that microorganisms differ in several ways, some of which may reflect neutral phenotypic evolution. For making his case, Bonner referred to interspecies differences and morphological traits. Here we consider intraspecies differences and physiological traits. As a case‐study, we examine the production of an extracellular cyclic 3 falseprefix′,5 falseprefix′ monophosphate phosphodiesterase in the cellular slime mold Dictyostelium discoideum. Temporal profiles of phosphodiesterase activity differ significantly between wild‐type strains. From that we argue that the inference drawn initially from studies on a single wild‐type, namely that the profile displayed by it pointed to an adaptive role, was mistaken. We generalize the conclusion to suggest that physiological differences exhibited by microorganisms of the same species may, but need not, reflect adaptations to different environments. Rather, the differences could be related to the fact that microorganisms live in groups whose composition can vary between homogeneous (clonal) and heterogeneous (polyclonal). More than one physiological profile is consistent with the normal development of the group in a given environment; the alternatives are neutral. When studying microbial physiology and behavior, it is expected that the observations are made on a clonal population; genetic (and so phenotypic) heterogeneity is carefully guarded against. As the example from D. discoideum shows, an unintended consequence of overlooking phenotypic heterogeneity is that one can fall into the trap of accepting a seemingly plausible, but possibly erroneous, adaptive explanation for a “normal” wild‐type phenotype.

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Clonal Diversity in Populations of Polysphondylium Pallidum, A Cellular Slime Mold

Cited by 8 publications

References 34 publications

Genetic structure of a natural population of Dictyostelium discoideum, a cellular slime mould

Genetic structure of a natural population of Dictyostelium discoideum, a cellular slime mould

Multiple Dictyostelid Species Destroy Biofilms of Klebsiella oxytoca and Other Gram Negative Species

Many roads lead to Rome: Neutral phenotypes in microorganisms

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