Application of a Specific and Sensitive RadiometricAssay for Microbial Lipase Activities in Marine Water Samplesfrom the Lagoon ofNouméa
| Autor: | Jean-Pascal Torréton, Vincent Arondel, Olivier Galy, Nicolas Bourguet, Madeleine Goutx |
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| Rok vydání: | 2003 |
| Předmět: |
RADIOMETRIE
Triacylglycerol lipase Fresh Water BACTERIE HYDROLYSE Tritium Sensitivity and Specificity Applied Microbiology and Biotechnology chemistry.chemical_compound Hydrolysis New Caledonia Methods ETUDE COMPARATIVE BIOLOGIE MARINE ANALYSE ISOTOPIQUE Triolein FLUORESCENCE Lipase Radiometry Hymecromone METHODE D'ANALYSE Bacteria Ecology biology Triglyceride Extraction (chemistry) Substrate (chemistry) ENZYME LYTIQUE EAU DE MER chemistry Biochemistry ACTIVITE ENZYMATIQUE biology.protein LIPASE Food Science Biotechnology |
| Zdroj: | Applied and Environmental Microbiology. 69:7395-7400 |
| ISSN: | 1098-5336 0099-2240 |
| Popis: | Marine microbiologists commonly assay lipase activities by using a synthetic fluorescent analog, 4-methylumbelliferyl (MUF)-oleate. The technique is convenient, but it is considered to be unspecific because of the structure of this analog. This study reports the design of a new specific and sensitive lipase assay based on the use of a radiolabeled triglyceride, [ 3 H]triolein. Free fatty acids (FFA) resulting from its hydrolysis are isolated as a function of time in a one-step liquid-liquid extraction and then radioassayed. MUF-oleate and [ 3 H]triolein techniques were compared by measuring lipase activities at similar substrate concentrations along a trophic gradient in the Southwest Lagoon of New Caledonia, near Nouméa. Hydrolysis rates decreased from the nearshore station to the offshore station and showed similar trends regardless of the technique used. Rates decreased from 5.83 to 0.88 nmol of FFA · liter −1 · h −1 and from 0.76 to 0.23 nmol of 3 H-FFA · liter −1 · h −1 , respectively. These results appeared to be consistent with bacterial production results, which also decreased similarly (from 0.59 to 0.26μ g of C · liter −1 · h −1 ). However, the ratio of MUF-oleate activities to [ 3 H]triolein activities, which was constant at the offshore stations (3.8 ± 0.1), gradually increased at the nearshore stations (from 4.1 to 7.6). This result shows that the two assays respond in different ways to changes in environmental conditions and validates the need to set up more specific enzymatic assays. |
| Databáze: | OpenAIRE |
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