Ultrastructural changes in the myxamoebae of <i>Physarum polycephalum</i> in response to a microcyst-inducing concentration of mannitol

Williams, Lynda M.; Lafontaine, J. G.

doi:10.1139/b84-044

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…cultures or in the mannitol medium. Our results did not support the suggestion by Williams & Lafontaine (1984) that amoebae at different growth stages responded differently to mannitol.…”

Section: Resultscontrasting

confidence: 99%

“…Within each experiment, all samples gave similar O/O T R C ; there was no evidence that %TRC was affected by cell density either in the SDM cultures or in the mannitol medium. Our results did not support the suggestion by Williams & Lafontaine (1984) that amoebae at different growth stages responded differently to mannitol.…”

Section: Mannitol Induction Of Trc Formation In Liquid Culturescontrasting

confidence: 99%

“…These cells resembled the 'young cysts' observed by Haars et al (1979) in cultures of P. polycephalum amoebae after 24 h mannitol treatment. A similar cell resulting from mannitol treatment of a liquid culture is shown in an electron micrograph published by Williams & Lafontaine (1984) ; this cell is described as a ' mature cyst', although it also lacks a clear cell wall.…”

Section: Viability Of Mannitol-induced Trc After Triton Treatmentmentioning

confidence: 88%

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Contact with a solid substratum induces cysts in axenic cultures ofPhysarum polycephalum amoebae: mannitol-induced detergent-resistant cells are not true cysts

et al. 1997

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Previous workers reported that Physarum polycephalum amoebae cultured in liquid axenic medium were induced to form cysts b y the addition of mannitol. Their criterion for encystment was the formation of detergent (Triton)-resistant cells (TRC). In this study the frequencies of TRC in suspensions of amoebae from various treatments were compared with counts of cell types identified by transmission electron microscopy. Amoebae treated with mannitol in axenic liquid culture formed 50% TRC after 17 h but no walled cysts were found. It was concluded that TRC induced by mannitol were dense, rounded cells without walls. In contrast, TRC formed after growth to stationary phase on bacterial lawns were walled cells. When resuspended in growth medium, most mannitol-induced TRC reverted to active amoebae within a f e w minutes, whereas TRC formed on bacteria remained T r i t o n resistant for many hours. It was concluded that delayed reversion of TRC was a more reliable indication of wall formation than Triton resistance alone. Transfer of amoebae from liquid culture to the surface of diluted axenic agar medium resulted in the formation of walled cysts identical in appearance with those formed on bacterial lawns. The results indicated that efficient encystment requires a solid substratum as well as nutrient deprivation.

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“…cultures or in the mannitol medium. Our results did not support the suggestion by Williams & Lafontaine (1984) that amoebae at different growth stages responded differently to mannitol.…”

Section: Resultscontrasting

confidence: 99%

Section: Mannitol Induction Of Trc Formation In Liquid Culturescontrasting

confidence: 99%