<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Baldantoni, Daniela</style></author><author><style face="normal" font="default" size="100%">Fagnano, Massimo</style></author><author><style face="normal" font="default" size="100%">Alfani, Anna</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Tropospheric ozone effects on chemical composition and decomposition rate of Quercus ilex L. leaves.</style></title><secondary-title><style face="normal" font="default" size="100%">The Science of the total environment</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Air Pollutants</style></keyword><keyword><style  face="normal" font="default" size="100%">Air Pollutants: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Air Pollutants: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Air Pollutants: toxicity</style></keyword><keyword><style  face="normal" font="default" size="100%">Atmosphere</style></keyword><keyword><style  face="normal" font="default" size="100%">Atmosphere: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon cycle</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Decaying leaf composition</style></keyword><keyword><style  face="normal" font="default" size="100%">Holm oak leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Lignin</style></keyword><keyword><style  face="normal" font="default" size="100%">Lignin: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Lignin: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean area</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen cycle</style></keyword><keyword><style  face="normal" font="default" size="100%">Nitrogen: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Nitrogen: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Ozone</style></keyword><keyword><style  face="normal" font="default" size="100%">ozone exposure</style></keyword><keyword><style  face="normal" font="default" size="100%">Ozone: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Ozone: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Ozone: toxicity</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: metabolism</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><publisher><style face="normal" font="default" size="100%">Elsevier B.V.</style></publisher><volume><style face="normal" font="default" size="100%">409</style></volume><pages><style face="normal" font="default" size="100%">979-984</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We determined the effects of tropospheric ozone on the chemical composition of Quercus ilex L. leaves and their decomposition, with a view to assessing the influence of ozone on nutrient cycling and the sustainability of Mediterranean holm oak forests. Forming one of the most widespread thermophilous vegetation communities in the area, Q. ilex is a dominant and widespread evergreen oak in the Mediterranean, where concentrations of tropospheric ozone are particularly high. The dynamics of carbon, nitrogen, lignin and cellulose concentrations were monitored for six months during the decomposition of leaves from plants subjected to controlled ozone exposure in open-top chambers. Ozone-exposed leaves, compared to unexposed leaves, showed no significant differences in C, N, lignin and cellulose concentrations prior to the incubation in mesocosms. However, during decomposition, leaves from plants exposed to ozone lost C significantly more slowly and showed a higher C/N ratio than unexposed leaves. Ozone exposure significantly slowed down the decomposition rate, indicating a negative effect of tropospheric ozone on nutrient cycling, which may reduce long-term sustainability of the holm oak forest.</style></abstract><accession-num><style face="normal" font="default" size="100%">21167557</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Criquet, Stéven</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Measurement and characterization of cellulase activity in sclerophyllous forest litter.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of microbiological methods</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Buffers</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulase</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulase: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulase: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Endoglucanase</style></keyword><keyword><style  face="normal" font="default" size="100%">Extraction</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzyme</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzymes</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzymes: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">litter</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves: enzymology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: enzymology</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Trees</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/11997167</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">50</style></volume><pages><style face="normal" font="default" size="100%">165 - 173</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cellulases are enzymatic proteins which hydrolyze cellulose polymers to smaller oligosaccharides, cellobiose and glucose. They consist in three major types of enzymes: endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91) and beta-glucosidases (EC 3.2.1.21) which play an essential role in carbon turnover of forest ecosystem. The aim of this study was firstly to determine the parameters (i.e. buffer type, pH, temperature, quantity of litter, incubation time and reagent type) which affect the measurement of cellulase activity in a sclerophyllous forest litter, and secondly to compare two methods for measuring cellulase activity: a direct method and an extraction method. In the direct method, the litter was directly incubated with a buffered solution containing the enzyme substrate, whereas in the extraction method, the cellulases were firstly extracted before measuring their activity. The results were compared with other studies about soil cellulase activity, and it appeared that several parameters (buffer type, pH, temperature and sample quantity) which influence the measurement of cellulase activity differ according to whether a soil or a litter is considered. Concerning the procedure used for the measurement of cellulase activity, results showed that the activity values were higher when using an extraction procedure than when using a direct procedure. The extraction procedure, combined with a concentration stage of the extract, also allowed electrophoretic analysis (PAGE) of the cellulases extracted from the litter. The electrophoretic pattern revealed two cellulase isoenzymes which may be related to the occurrence of two pH-activity peaks of these enzymes when citrate buffer was used for the measurement of cellulase activity in the litter.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 11997167</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Criquet, Stéven</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Measurement and characterization of cellulase activity in sclerophyllous forest litter.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of microbiological methods</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Buffers</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulase</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulase: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulase: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose</style></keyword><keyword><style  face="normal" font="default" size="100%">Cellulose: metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Endoglucanase</style></keyword><keyword><style  face="normal" font="default" size="100%">Extraction</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzyme</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzymes</style></keyword><keyword><style  face="normal" font="default" size="100%">Isoenzymes: analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">litter</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Leaves: enzymology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: enzymology</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Trees</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><volume><style face="normal" font="default" size="100%">50</style></volume><pages><style face="normal" font="default" size="100%">165-173</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Cellulases are enzymatic proteins which hydrolyze cellulose polymers to smaller oligosaccharides, cellobiose and glucose. They consist in three major types of enzymes: endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91) and beta-glucosidases (EC 3.2.1.21) which play an essential role in carbon turnover of forest ecosystem. The aim of this study was firstly to determine the parameters (i.e. buffer type, pH, temperature, quantity of litter, incubation time and reagent type) which affect the measurement of cellulase activity in a sclerophyllous forest litter, and secondly to compare two methods for measuring cellulase activity: a direct method and an extraction method. In the direct method, the litter was directly incubated with a buffered solution containing the enzyme substrate, whereas in the extraction method, the cellulases were firstly extracted before measuring their activity. The results were compared with other studies about soil cellulase activity, and it appeared that several parameters (buffer type, pH, temperature and sample quantity) which influence the measurement of cellulase activity differ according to whether a soil or a litter is considered. Concerning the procedure used for the measurement of cellulase activity, results showed that the activity values were higher when using an extraction procedure than when using a direct procedure. The extraction procedure, combined with a concentration stage of the extract, also allowed electrophoretic analysis (PAGE) of the cellulases extracted from the litter. The electrophoretic pattern revealed two cellulase isoenzymes which may be related to the occurrence of two pH-activity peaks of these enzymes when citrate buffer was used for the measurement of cellulase activity in the litter.</style></abstract><accession-num><style face="normal" font="default" size="100%">11997167</style></accession-num></record></records></xml>