Functional analysis of the <i>Zygosaccharomyces rouxii</i> Fps1p homologue

Tang, Xue; Kayingo, Gerald; Prior, Bernard A.

doi:10.1002/yea.1232

Cited by 20 publications

(21 citation statements)

References 31 publications

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“…However, despite our efforts to investigate the relative importance of glycerol efflux and glycerol uptake for the survival of C. albicans in the presence of osmotic stress, we have yet to identify the gene(s) and protein(s) responsible for C. albicans glycerol efflux. Just as was the case in Schizosaccharomyces pombe (Kayingo et al, 2004), deletion of the only aqua-or aquaglyceroporin in the C. albicans genome, CaAQY1 (Carbrey et al, 2001;Tang et al, 2005), did not alter glycerol efflux as compared to wild-type (data not shown). In our effort for a full understanding of glycerol homeostasis and its role in the stress response and virulence of C. albicans, characterization of glycerol efflux by C. albicans continues to be a focus of our research.…”

Section: Discussionmentioning

confidence: 61%

A permease encoded by STL1 is required for active glycerol uptake by Candida albicans

et al. 2009

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Candida albicans accumulates large amounts of the polyols glycerol and D-arabitol when the cells are exposed to physiological conditions relevant to stress and virulence in animals. Intracellular concentrations of glycerol are determined by rates of glycerol production and catabolism and of glycerol uptake and efflux through the plasma membrane. We and others have studied glycerol production in C. albicans, but glycerol uptake by C. albicans has not been studied. In the present study, we found that [14 C]glycerol uptake by C. albicans SC5314 was (i) accumulative; (ii) dependent on proton-motive force; (iii) unaffected by carbon source; and (iv) unaffected by large molar excesses of D-arabitol or other polyols. The respective K m and V max values were 2.1 mM and 460 mmol h "1 (g dry wt) "1 in glucose medium and 2.6 mM and 268 mmol h "1 (g dry wt) "1 in glycerol medium. To identify the C. albicans glycerol uptake protein(s), we cloned the C. albicans homologues of the Saccharomyces cerevisiae genes GUP1 and STL1, both of which are known to be involved in glycerol transport. When multicopy plasmids encoding C. albicans STL1, C. albicans STL2 and C. albicans GUP1 were introduced into the corresponding S. cerevisiae null mutants, the transformants all acquired the ability to grow on minimal glycerol medium; however, only S. cerevisiae stl1 null mutants transformed with C. albicans STL1 actively took up extracellular [ 14 C]glycerol. When both chromosomal alleles of C. albicans STL1 were deleted from C. albicans BWP17, the resulting stl1 null mutants grew poorly on minimal glycerol medium, and their ability to transport [ 14 C]glycerol into the cell was markedly reduced. In contrast, deletion of both chromosomal alleles of C. albicans STL2 or of C. albicans GUP1 had no significant effects on [ 14 C]glycerol uptake or the ability to grow on minimal glycerol medium. Northern blot analysis indicated that C. albicans STL1 was expressed in both glucose and glycerol media, conditions under which we detected wild-type active glycerol uptake. Furthermore, STL1 was highly expressed in salt-stressed cells; however, the stl1 null mutant was no more sensitive to salt stress than wild-type controls. We also detected high levels of STL2 expression in glycerol-grown cells, even though deletion of this gene did not influence glycerol uptake activity in glycerol-grown cells. We conclude from the results above that a plasma-membrane H + symporter encoded by C.albicans STL1 actively transports glycerol into C. albicans cells.

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Section: Discussionmentioning

confidence: 61%

A permease encoded by STL1 is required for active glycerol uptake by Candida albicans

et al. 2009

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“…It is, however, probable that Fps1p (an aquaglyceroporin highly conserved amongst yeasts) is also important for acetic acid resistance in Zygosaccharomyces. We have observed that an fps1 mutant of Z. rouxii [39] (Tang et al, 2005) exhibits an elevated resistance to this acid relative to the corresponding wild-type Z. rouxii (unpublished observations).…”

Section: Hog1p Map Kinase Directs a Different Stress Response When Acmentioning

confidence: 88%

Novel stress responses facilitate Saccharomyces cerevisiae growth in the presence of the monocarboxylate preservatives

Mollapour

Shepherd

Piper

2008

Yeast

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Certain yeasts are relatively resistant to the small number of monocarboxylic acids allowed in food preservation, with the result that these preservatives often have to be used in high concentrations in order to prevent spoilage. When grown at slightly acid pH, Saccharomyces cerevisiae acquires elevated resistance to these acids by means of discrete stress responses. Acquisition of resistance to acetic acid involves loss of Fps1p, the aquaglyceroporin of the plasma membrane that facilitates the passive diffusional entry of this acid into cells. Acetic acid stress transiently activates Hog1p mitogen-activated protein kinase, which then directly phosphorylates Fps1p in order to target this channel for endocytosis and degradation in the vacuole. Other carboxylate preservatives (propionate, sorbate or benzoate) are too large to traverse the Fps1p pore. Instead, being more lipophilic than acetic acid, they enter cells mainly by a process of non-facilitated diffusion across the plasma membrane. Once inside the cell, these acids activate War1p, a transcription factor that induces the gene for the Pdr12p plasma membrane ATP-binding cassette transporter. Pdr12p lowers the intracellular levels of propionate, sorbate or benzoate by catalysing the active efflux of the preservative anion from the cell. Still other mechanisms of weak acid resistance are found in Zygosaccharomyces, including a capacity for the oxidative degradation of sorbic and benzoic acids conferred by a mitochondrial monooxygenase, a system absent in S. cerevisiae.

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“…For example, arabitol and glycerol are retained intracellularly during hyper-osmotic stress, but are rapidly released during hypo-osmotic stress. Tang et al (2005) used Zygosaccharomyces rouxii Fps1p gene mutants in studies of hypo-and hyper-osmotic shock, and showed that the concentrations of arabitol and glycerol were significantly greater in the mutants than in the wild type of the fungus.…”

Section: Introductionmentioning

confidence: 99%

Biochemical characteristics ofTrichoderma atrovirideassociated with conidium fitness for biological control

Daryaei

Jones

Alizadeh

et al. 2015

Biocontrol Science and Technology

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Effects of abiotic factors during production (temperature, nutrients, water activity, pH) on conidium fitness (quantity and quality) of Trichoderma atroviride LU132 (a key biocontrol agent) were studied. Conidia from the culturing regimes which resulted in greatest and least bioactivity against Rhizoctonia solani in dual culture assays were selected to assess effects of storage conditions on conidial fitness over time. Further studies assessed interaction effects of temperatures (20 or 30°C) and sugars (dextrose or sucrose) on conidium germination and bioactivity as fresh conidia, or after 6 months of storage. Biochemical analyses of sugars and fatty acids were carried out to determine relationships between quality variations and cellular characteristics for conidia produced in different culturing conditions. Low trehalose content in conidia (e.g. at 20°C) was associated with the least conidium fitness, although high trehalose content did not necessarily support conidium fitness. High proportions of total fatty acids in conidia were mostly associated with the least conidium fitness. When Trichoderma was grown at high carbon to nitrogen ratio (e.g. at C:N 160:1), the total conidium fatty acids content increased. This study also indicated that the monosaccharide dextrose is metabolically optimal for T. atroviride LU132 at 20°C while the disaccharide sucrose is optimal at 30°C.These studies indicate that physical growth conditions and nutritional requirements attribute in conidium fitness of T. atroviride LU132, and provide important knowledge supporting optimum production of biocontrol agents based on T. atroviride, and possibly other similar biocontrol agents.

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Functional analysis of the Zygosaccharomyces rouxii Fps1p homologue

Cited by 20 publications

References 31 publications

A permease encoded by STL1 is required for active glycerol uptake by Candida albicans

A permease encoded by STL1 is required for active glycerol uptake by Candida albicans

Novel stress responses facilitate Saccharomyces cerevisiae growth in the presence of the monocarboxylate preservatives

Biochemical characteristics ofTrichoderma atrovirideassociated with conidium fitness for biological control

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