Different developmental programs for amoebal and plasmodial encystment in Physarum polycephalum

Binette, Franrçois; Pallotta, Dominick; Lemieux, Gérald

doi:10.1007/bf00365650

Cited by 6 publications

(3 citation statements)

References 24 publications

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“…Total or poly(A)*RNAs were isolated from the various developmental stages as described previously (Pallotta et al, 1986b;Binette et al, 1988). Ten micrograms of total RNA or 2 fig of poly(A)*RNA were denatured with 0.66 M formaldehyde and fractionated on 1.5% agarose gels containing 0.66 M formaldehyde and 20 mM MOPS buffer pH 7.0.…”

Section: Northern Blotsmentioning

confidence: 99%

Cell-Specific Expression of a Profilin Gene Family

Binette

Bénard²,

Laroche³

et al. 1990

DNA and Cell Biology

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Profilin is a ubiquitous eukaryotic protein that inhibits actin polymerization. We cloned and sequenced the two profilin genes from the acellular slime mold Physarum polycephalum. The genes, proA and proP, each contain two introns. Primer extension experiments showed two possible transcription start sites in the profilin A gene and one start site in the profilin P gene. The profilin A mRNA has two polyadenylation sites, which yield mRNAs of about 600 and 500 nucleotides. The profilin P mRNA has a single polyadenylation site. The protein sequences were deduced from cDNA nucleotide sequencing. The profilin A and profilin P proteins contain 125 amino acids and are 66% identical in sequence. They show sequence similarity to Acanthamoeba (approximately 54%), yeast (approximately 46%), mouse (approximately 22%), calf (approximately 21%), and human (approximately 21%) profilins. The presence of the profilin A and profilin P mRNAs was studied throughout the life cycle. Profilin A mRNA was found in amebas, encysted amebas, and mature spores. The profilin P mRNA was present in plasmodia and spherulating plasmodia. Most cell types of P. polycephalum contain either the amebal or the plasmodial profilin mRNA, and no cell contains both mRNAs. This is the first evidence for developmental regulation of profilin isoforms.

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Section: Northern Blotsmentioning

confidence: 99%

Cell-Specific Expression of a Profilin Gene Family

Binette

Bénard²,

Laroche³

et al. 1990

DNA and Cell Biology

Self Cite

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“…Thus, although Triton tests provide a quick and convenient method for detecting cysts among cells suspended in media such as SDM, their use in media of high osmotic pressure can be misleading. Detergent resistance was the criterion for encystment used by Binette et al (1988) when they attempted to identify encystment-specific genes in a cDNA library constructed from TRC induced by glucose. Although they identified two mRNAs specific to the TRC, our observations suggest that these cells may not have been true cysts.…”

Section: Conclusion Detergent Resistance Is Not a Reliable Test For mentioning

confidence: 99%

“…In contrast, cysts formed on bacteria required many hours for reversion in growth medium ( Gorman et al ., 1977). Binette et al . (1988) reported that encystment of P. polycephalum amoebae was induced in liquid cultures by prolonged incubation in the presence of glucose, but apparently relied entirely on detergent resistance to detect cysts.…”

Section: Introductionmentioning

confidence: 99%

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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