Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Candida dubliniensis is a newly described species that is closely related phylogenetically to Candida albicans and that is commonly associated with oral candidiasis in human immunodeficiency virus-positive patients. Several recent studies have attempted to elucidate phenotypic and genotypic characteristics of use in separating the two species. However, results obtained with simple phenotypic tests were too variable and tests that provided more definitive data were too complex for routine use in the clinical laboratory setting. The objective of this study was to determine if reproducible identification of C. dubliniensis could be obtained with commercial identification kits. The substrate reactivity profiles of 80 C. dubliniensis isolates were obtained by using the API 20C AUX, ID 32 C, RapID Yeast Plus, VITEK YBC, and VITEK 2 ID-YST systems. The percentages of C. dubliniensis isolates capable of assimilating or hydrolyzing each substrate were compared with the percentages from the C. albicans profiles in each kit's database, and the results were expressed as percent C. dubliniensis and percent C. albicans. Any substrate that showed >50% difference in reactivity was considered useful in differentiating the species. In addition, assimilation of methyl-alpha-D-glucoside (MDG), D-trehalose (TRE), and D-xylose (XYL) by the same isolates was investigated by the traditional procedure of Wickerham and Burton (L. J. Wickerham and K. A. Burton, J. Bacteriol. 56:363-371, 1948). At 48 h (the time recommended by the manufacturer for its new database), we found that the assimilation of four carbohydrates in the API 20C AUX system could be used to distinguish the species, i.e., glycerol (GLY; 88 and 14%), XYL (0 and 88%), MDG (0 and 85%), and TRE (15 and 97%). Similarly, results with the ID 32 C system at 48 h showed that XYL (0 and 98%), MDG (0 and 98%), lactate (LAT; 0 and 96%), and TRE (30 and 96%) could be used to separate the two species. Phosphatase (PHS; 9 and 76%) and alpha-D-glucosidase (23 and 94%) proved to be the most useful for separation of the species in the RapID Yeast Plus system. While at 24 h the profiles obtained with the VITEK YBC system showed that MDG (10 and 95%), XYL (0 and 95%), and GLY (26 and 80%) could be used to separate the two species, at 48 h only XYL (6 and 95%) could be used to separate the two species. The most useful substrates in the VITEK 2 ID-YST system were TRE (1 and 89%), MDG (1 and 99%), LAT (4 and 98%), and PHS (83 and 1%). While the latter kit was not yet commercially available at the time of the study, it would appear to be the most valuable for the identification of C. dubliniensis. Although assimilation of MDG, TRE, and XYL proved to be the most useful for species differentiation by the majority of commercial systems, the results with these carbohydrates by the Wickerham and Burton procedure were essentially the same for both species, albeit following protracted incubation. Thus, it is the rapidity of the assimilation achieved with the commercial systems that allows the differentiation of C. dubliniensis from C. albicans.
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PMID:Rapid identification of Candida dubliniensis with commercial yeast identification systems. 1052 48

Cedar waxwings (Bombycilla cedrorum) feed predominantly on fruits that are rich in simple sugars and low in nitrogen, supplementing this diet with arthropod prey during the summer months as well as flowers and tree sap in springtime. In contrast, thrushes feed extensively on fatty, protein-rich invertebrate prey, supplemented with sugary and lipid-rich fruits. Simple sugars and fats are digested and/or absorbed by distinctly different physiological mechanisms, which suggests the possibility of contrasting digestive strategies in animals specialized to diets containing one of these two energy sources. In this study, we quantified enzymatic activity of three membrane-bound intestinal enzymes of cedar waxwings and five species of thrushes to explore this aspect of their digestive physiology. These enzymes catalyze the final steps in the digestion of carbohydrates (sucrase-isomaltase and maltase-glucoamylase) and protein (aminopeptidase-N). The two carbohydrases are homologous enzymes with overlapping functions; both enzymes catalyze the hydrolysis of maltase and isomaltase. The membrane-bound digestive enzyme systems that we described for cedar waxwings and thrushes can be explained by the particular nutrients contained within their respective natural diets. Consistent with previous work, cedar waxwings displayed intestinal sucrase activity, whereas thrushes did not. Correspondingly, cedar waxwings eat some foods containing sucrose, whereas thrushes do not. Sucrase-isomaltase conferred all maltase and isomaltase activity in cedar waxwings. In contrast, all maltase and isomaltase activity in thrushes was necessarily sucrase independent, which indicated the presence of maltase-glucoamylase. The absence of sucrase-independent maltase activity in cedar waxwings suggests that sucrase-isomaltase obviates the need for maltase-glucoamylase. Indeed, total maltase and isomaltase activities were much higher in cedar waxwings than in thrushes. Neither waxwings nor thrushes eat starchy foods; sucrase-isomaltase in waxwings and maltaseglucoamylase in thrushes probably function in digesting glycogen in animal foods. We suggest that digestive traits associated with specialization to monosaccharide-rich fruits (lack of a grinding gizzard) by frugivorous waxwings and thrushes may prevent utilization of starchy seeds. Total aminopeptidase-N activity in cedar waxwings was indistinguishable from the allometric pattern among thrush species, but the distribution of this enzyme along the intestines of waxwings and thrushes was distinctly different, which demonstrates that total enzyme activity can be insufficient as a descriptor of the functional activity of brush border enzymes. Aminopeptidase-N activity peaked in the anterior part of the intestines of thrushes and in the terminal portion of the intestines of waxwings, which suggests contrasting strategies for protein digestion from fatty versus sugary diets, respectively.
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PMID:The membrane-bound intestinal enzymes of waxwings and thrushes: adaptive and functional implications of patterns of enzyme activity. 1143 43