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- Amundin, Mats, et al.
(författare)
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Estimating the abundance of the critically endangered Baltic Proper harbour porpoise (Phocoena phocoena) population using passive acoustic monitoring
- 2022
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 12:2
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Tidskriftsartikel (refereegranskat)abstract
- Knowing the abundance of a population is a crucial component to assess its conservationstatus and develop effective conservation plans. For most cetaceans, abundanceestimation is difficult given their cryptic and mobile nature, especially when thepopulation is small and has a transnational distribution. In the Baltic Sea, the numberof harbour porpoises (Phocoena phocoena) has collapsed since the mid-20thcenturyand the Baltic Proper harbour porpoise is listed as Critically Endangered by the IUCNand HELCOM; however, its abundance remains unknown. Here, one of the largestever passive acoustic monitoring studies was carried out by eight Baltic Sea nationsto estimate the abundance of the Baltic Proper harbour porpoise for the first time. Bylogging porpoise echolocation signals at 298 stations during May 2011–April2013,calibrating the loggers’ spatial detection performance at sea, and measuring the clickrate of tagged individuals, we estimated an abundance of 71–1105individuals (95% CI,point estimate 491) during May–Octoberwithin the population's proposed managementborder. The small abundance estimate strongly supports that the Baltic Properharbour porpoise is facing an extremely high risk of extinction, and highlights theneed for immediate and efficient conservation actions through international cooperation.It also provides a starting point in monitoring the trend of the populationabundance to evaluate the effectiveness of management measures and determine itsinteractions with the larger neighboring Belt Sea population. Further, we offer evidencethat design-basedpassive acoustic monitoring can generate reliable estimatesof the abundance of rare and cryptic animal populations across large spatial scales.
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- Gloster, Tracey M., et al.
(författare)
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Characterization and three-dimensional structures of two distinct bacterial xyloglucanases from families GH5 and GH12
- 2007
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 282:26, s. 19177-19189
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Tidskriftsartikel (refereegranskat)abstract
- The plant cell wall is a complex material in which the cellulose microfibrils are embedded within a mesh of other polysaccharides, some of which are loosely termed hemicellulose. One such hemicellulose is xyloglucan, which displays a beta-1,4-linked D-glucose backbone substituted with xylose, galactose, and occasionally fucose moieties. Both xyloglucan and the enzymes responsible for its modification and degradation are finding increasing prominence, reflecting both the drive for enzymatic biomass conversion, their role in detergent applications, and the utility of modified xyloglucans for cellulose fiber modification. Here we present the enzymatic characterization and three-dimensional structures in ligand free and xyloglucan- oligosaccharide complexed forms of two distinct xyloglucanases from glycoside hydrolase families GH5 and GH12. The enzymes, Paenibacillus pabuli XG5 and Bacillus licheniformis XG12, both display open active center grooves grafted upon their respective (beta/alpha)(8) and beta-jelly roll folds, in which the side chain decorations of xyloglucan may be accommodated. For the beta-jelly roll enzyme topology of GH12, binding of xylosyl and pendant galactosyl moieties is tolerated, but the enzymeis similarly competent in the degradation of unbranched glucans. In the case of the (beta/alpha)(8) GH5 enzyme, kinetically productive interactions are made with both xylose and galactose substituents, as reflected in both a high specific activity on xyloglucan and the kinetics of a series of aryl glycosides. The differential strategies for the accommodation of the side chains of xyloglucan presumably facilitate the action of these microbial hydrolases in milieus where diverse and differently substituted substrates may be encountered.
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