Identification of yeast phase of pathogenic fungi by the specificity of their aminopeptidase(s)

Lee, K.L.; Reca, Maria E.; Watson, Ronald R.; Campbell, Charlotte C.

doi:10.1080/00362177585190251

Cited by 28 publications

(16 citation statements)

References 12 publications

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“…The names, genotypes, and origins of the C. albicans strains used in the present study are listed in Table S1 in the supplemental material. All strains were maintained at 25°C on agar plates containing YPD medium or modified Lee's medium (4,23) supplemented with phloxine B (5 g/ml), which distinguishes between white and opaque colonies (3). For experimental purposes, cells from 5-day colonies were inoculated into fresh liquid modified Lee's medium and grown at 25°C in a water bath with vigorous shaking until they reached stationary phase.…”

Section: Methodsmentioning

confidence: 99%

Self-Induction of a / a or α/α Biofilms in Candida albicans Is a Pheromone-Based Paracrine System Requiring Switching

et al. 2011

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Like MTL-heterozygous (a/␣) cells, white MTL-homozygous (a/a or ␣/␣) cells of Candida albicans, to which a minority of opaque cells of opposite mating type have been added, form thick, robust biofilms. The latter biofilms are uniquely stimulated by the pheromone released by opaque cells and are regulated by the mitogenactivated protein kinase signal transduction pathway. However, white MTL-homozygous cells, to which opaque cells of opposite mating type have not been added, form thinner biofilms. Mutant analyses reveal that these latter biofilms are self-induced. Self-induction of a/a biofilms requires expression of the ␣-receptor gene STE2 and the ␣-pheromone gene MF␣, and self-induction of ␣/␣ biofilms requires expression of the a-receptor gene STE3 and the a-pheromone gene MFa. In both cases, deletion of WOR1, the master switch gene, blocks cells in the white phenotype and biofilm formation, indicating that self-induction depends upon low frequency switching from the white to opaque phenotype. These results suggest a self-induction scenario in which minority opaque a/a cells formed by switching secrete, in a mating-type-nonspecific fashion, ␣-pheromone, which stimulates biofilm formation through activation of the ␣-pheromone receptor of majority white a/a cells. A similar scenario is suggested for a white ␣/␣ cell population, in which minority opaque ␣/␣ cells secrete a-pheromone. This represents a paracrine system in which one cell type (opaque) signals a second highly related cell type (white) to undergo a complex response, in this case the formation of a unisexual white cell biofilm.Approximately 90% of Candida albicans isolates are a/␣ and 10% either a/a or ␣/␣ (24, 25, 50). For a/␣ strains to mate, they must undergo homozygosis to a/a or ␣/␣ (20, 21, 29). Then, a/a and ␣/␣ strains must switch from the white to opaque phenotype (46) in order to be mating competent (27,30). Opaque cells secrete a cell type-specific pheromone, which stimulates the mating response in cells of opposite mating type (5,26,38). However, in a fashion unique to C. albicans, these pheromones also induce mating-incompetent white cells, but not matingcompetent opaque cells, of opposite mating type to form robust biofilms, similar morphologically to those formed by a/␣ cells (13, 42-44, 48, 53-55). These MTL-homozygous white cell biofilms have been demonstrated in vitro to facilitate mating between opaque a/a and ␣/␣ cells (13,48).Although the addition of minority opaque cells of opposite mating type (1 to 10%) to a population of white cells increases the thickness of the final white cell biofilm by more than 50%, single-sex white a/a or ␣/␣ cell populations, to which cells of opposite mating types have not been added, also form robust biofilms composed of a basal layer of yeast cells and a thick upper layer of hyphae and matrix (13,(42)(43)(44)(53)(54)(55). We previously showed that deletion of the ␣-receptor gene STE2 results in highly reduced, abnormal white a/a cell biofilms in the absence of minority opaque ␣/␣ cells, suggesting t...

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Section: Methodsmentioning

confidence: 99%

Self-Induction of a / a or α/α Biofilms in Candida albicans Is a Pheromone-Based Paracrine System Requiring Switching

et al. 2011

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“…The substrate preference or relative hydrolysis of amino acyl /)NA by tears from various mammals is similar. This may reflect a specific function in maintaining a supply of certain free amino acids by aminopeptidase hydrolysis of the Nterminal amino acids from proteins or polypeptides since the substrate specificity of aminopeptidases in various fungi is species specific [W atson, 1976;Lee et al, 1975b]. The substrate specificities of fungal aminopeptidases reflect their amino acid needs in a defined, minimal media for either grow th or differentiation [L ee et al, 1975a] further suggesting a role in micro organisms at least for specific aminopeptidase activity.…”

Section: Discussionmentioning

confidence: 99%

Presence and Development with Age of Aminopeptidase(s) in Tears of Children and other Mammals

Watson

1977

Ophthalmic Res

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Proteolytic enzymes are known to appear in tears only following trauma to the cornea. Aminopeptidases, enzymes involved in the final degradation of proteins to free amino acids, were measured and partially characterized for substrate specificity in normal human and animal tears. In all species tested, aminopeptidase activity was greatest for methionine β-naphthylamide of the various synthetic analogs of N-terminal L-amino acids. The substrate specificities for aminopeptidase(s) in tears for 11 different mammals were very similar. In children aminopeptidase activity decreased with increasing age and was unaffected by nutritional status.

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“…However, in addition to protein biomarkers, specific cellular enzyme activities can serve as a more sensitive marker as their catalytic activity intrinsically serves to amplify their presence. In fact, the identification of bacteria through investigation of their microbial enzyme activity profiles was proposed over 30 years ago (Bascomb & Grantham 1975); the activities of enzymes such as phosphatases, esterases, aminopeptidases and glycosidases could be used to identify bacteria and fungi (Basile et al 1993;Kilian & Bulow 1976;Lee et al 1975;Maddocks & Greenan 1975).…”

Section: Introductionmentioning

confidence: 99%

Glycosidase activity profiling for bacterial identification by a chemical proteomics approach

Yu¹,

Rahman²,

Pohl³

2008

Biocatalysis and Biotransformation

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Genome sequencing projects are suggesting there are dozens of glycosidase sequences that could be used to fingerprint cell types and serve as starting points for biocatalyst discovery. Herein, we present a simple chemical proteomics approach to profile intracellular glycosidase activities of three different bacterial cell extracts using a synthetic a-and b-linked library of 18 representative substrates with electrospray ionization-mass spectrometry (ESI-MS) reaction monitoring. Three target bacteria Á Escherichia coli K12, Bacillus cereus and Pseudomonas aeruginosa Á can be easily differentiated by this method. Compared with traditional chromogenic and fluorogenic methods to profile bacterial enzyme activities individually, this MS-based method can detect multiple enzyme activities in one reaction and easily highlight activity differences between whole cell extracts.

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Identification of yeast phase of pathogenic fungi by the specificity of their aminopeptidase(s)

Cited by 28 publications

References 12 publications

Self-Induction of a / a or α/α Biofilms in Candida albicans Is a Pheromone-Based Paracrine System Requiring Switching

Self-Induction of a / a or α/α Biofilms in Candida albicans Is a Pheromone-Based Paracrine System Requiring Switching

Presence and Development with Age of Aminopeptidase(s) in Tears of Children and other Mammals

Glycosidase activity profiling for bacterial identification by a chemical proteomics approach

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