Abstract
The physicochemical forces that mediate attachment of yeasts to the phylloplane are unknown. Cell surface charge and hydrophobicity and adhesion to polystyrene, glass, and barley were assessed for wild-type Rhodosporidium toruloides and attachment-minus (Att-) mutants. Cells were grown under conditions promoting (excess carbon) or not promoting (excess nitrogen) capsule production. Hydrophobicity was measured by adhesion to xylenes, and surface charge characteristics were assessed by attachment to either DEAE (positive)- or carboxymethyl (CM) (negative)-Sephadex ion-exchange beads. Hydrophobicity and adhesiveness of nonencapsulated, wild-type R. toruloides decreased from mid-log to late stationary phase. Encapsulated wild-type R. toruloides cells were more hydrophobic and more adhesive than nonencapsulated cells. However, two encapsulated Att- mutants were more hydrophobic than the wild type and levels of adhesion of R. toruloides were similar on polystyrene and less hydrophobic glass surfaces. Adhesion of wild-type yeast to barley and polystyrene was correlated with attachment to CM-Sephadex beads, indicating a positive cell surface charge. Sixteen Att- mutants did not exhibit a positive cell surface charge, and wild-type yeast cells that did not attach to CM-Sephadex did not adhere to either polystyrene or barley. Wild-type R. toruloides attached to CM-Sephadex beads by the poles of the cells, indicating a localization of positive charge which was also visualized with India ink. We conclude that localized, positive charge, and not hydrophobic interactions, mediates attachment of R. toruloides to barley leaves.
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Claims 9
Claim · model-written summary
Nonencapsulated wild-type yeast hydrophobicity and adhesiveness decreased from mid-log to late stationary phase.
Verbatim
e0“Hydrophobicity and adhesiveness of nonencapsulated, wild-type R. toruloides decreased from mid-log to late stationary phase.”
Claim · model-written summary
Encapsulated wild-type yeast was more hydrophobic and adhesive than nonencapsulated cells.
Verbatim
e0“Encapsulated wild-type R. toruloides cells were more hydrophobic and more adhesive than nonencapsulated cells.”
Claim · model-written summary
Two encapsulated attachment-minus mutants were more hydrophobic than wild type.
Verbatim
e0“two encapsulated Att- mutants were more hydrophobic than the wild type”
t0“Rhodosporidium toruloides”
Claim · model-written summary
Yeast adhesion levels were similar on polystyrene and less hydrophobic glass.
Verbatim
e0“levels of adhesion of R. toruloides were similar on polystyrene and less hydrophobic glass surfaces”
Claim · model-written summary
Wild-type yeast adhesion to barley and polystyrene correlated with CM-Sephadex attachment, indicating positive surface charge.
- Taxon
- Rhodosporidium toruloidesRhodotorula toruloidest0
- Treatment
- attachment to CM-Sephadex beadse0
- Interactor
- barley
.jpg?width=60)
Hordeum vulgaree0host - Outcome
- Adhesione0
- Qualifier
- indicating a positive cell surface chargee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Adhesion of wild-type yeast to barley and polystyrene was correlated with attachment to CM-Sephadex beads, indicating a positive cell surface charge.”
t0“Rhodosporidium toruloides”
Claim · model-written summary
Sixteen attachment-minus mutants lacked a positive surface charge.
- Taxon
- Rhodosporidium toruloidesRhodotorula toruloidest0
- Material
- Att- mutantse0
- Outcome
- did not exhibit a positive cell surface chargee0
- Value
- Sixteene0
Not reportedDirection
Verbatim
e0“Sixteen Att- mutants did not exhibit a positive cell surface charge”
t0“Rhodosporidium toruloides”
Claim · model-written summary
Wild-type cells failing to attach to CM-Sephadex also failed to adhere to polystyrene or barley.
- Taxon
- Rhodosporidium toruloidesRhodotorula toruloidest0
- Material
- wild-typee0
- Interactor
- barleyHordeum vulgaree0host
- Outcome
- did not adhere to either polystyrene or barleye0
- Qualifier
- did not attach to CM-Sephadexe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“wild-type yeast cells that did not attach to CM-Sephadex did not adhere to either polystyrene or barley”
t0“Rhodosporidium toruloides”
Claim · model-written summary
Wild-type yeast attached to CM-Sephadex by cell poles, indicating localized positive charge also visualized with India ink.
- Taxon
- R. toruloidesRhodotorula toruloidese0
- Material
- Wild-typee0
- Organ / stage
- poles of the cellse0
- Outcome
- localization of positive chargee0
- Qualifier
- visualized with India inke0
Not reportedDirection
Verbatim
e0“Wild-type R. toruloides attached to CM-Sephadex beads by the poles of the cells, indicating a localization of positive charge which was also visualized with India ink.”
Claim · model-written summary
Localized positive charge rather than hydrophobic interactions mediates yeast attachment to barley leaves.
- Taxon
- R. toruloidesRhodotorula toruloidese0
- Organ / stage
- leavese0
- Interactor
- barleyHordeum vulgaree0host
- Outcome
- attachmente0
- Qualifier
- localized, positive charge, and not hydrophobic interactionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We conclude that localized, positive charge, and not hydrophobic interactions, mediates attachment of R. toruloides to barley leaves.”