| 1. |
- Anikin, Andrey, et al.
(författare)
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Human Non-linguistic Vocal Repertoire : Call Types and Their Meaning
- 2018
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Ingår i: Journal of Nonverbal Behavior. - : Springer Science and Business Media LLC. - 1573-3653 .- 0191-5886. ; 42:1, s. 53-80
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Tidskriftsartikel (refereegranskat)abstract
- Recent research on human nonverbal vocalizations has led to considerable progress in our understanding of vocal communication of emotion. However, in contrast to studies of animal vocalizations, this research has focused mainly on the emotional interpretation of such signals. The repertoire of human nonverbal vocalizations as acoustic types, and the mapping between acoustic and emotional categories, thus remain underexplored. In a cross-linguistic naming task (Experiment 1), verbal categorization of 132 authentic (non-acted) human vocalizations by English-, Swedish- and Russian-speaking participants revealed the same major acoustic types: laugh, cry, scream, moan, and possibly roar and sigh. The association between call type and perceived emotion was systematic but non-redundant: listeners associated every call type with a limited, but in some cases relatively wide, range of emotions. The speed and consistency of naming the call type predicted the speed and consistency of inferring the caller's emotion, suggesting that acoustic and emotional categorizations are closely related. However, participants preferred to name the call type before naming the emotion. Furthermore, nonverbal categorization of the same stimuli in a triad classification task (Experiment 2) was more compatible with classification by call type than by emotion, indicating the former's greater perceptual salience. These results suggest that acoustic categorization may precede attribution of emotion, highlighting the need to distinguish between the overt form of nonverbal signals and their interpretation by the perceiver. Both within- and between-call acoustic variation can then be modeled explicitly, bringing research on human nonverbal vocalizations more in line with the work on animal communication.
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| 2. |
- Arnling Bååth, Jenny, 1987, et al.
(författare)
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Biochemical and structural features of diverse bacterial glucuronoyl esterases facilitating recalcitrant biomass conversion
- 2018
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834 .- 1754-6834. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Lignocellulose is highly recalcitrant to enzymatic deconstruction, where the recalcitrance primarily results from chemical linkages between lignin and carbohydrates. Glucuronoyl esterases (GEs) from carbohydrate esterase family 15 (CE15) have been suggested to play key roles in reducing lignocellulose recalcitrance by cleaving covalent ester bonds found between lignin and glucuronoxylan. However, only a limited number of GEs have been biochemically characterized and structurally determined to date, limiting our understanding of these enzymes and their potential exploration. Results Ten CE15 enzymes from three bacterial species, sharing as little as 20% sequence identity, were characterized on a range of model substrates; two protein structures were solved, and insights into their regulation and biological roles were gained through gene expression analysis and enzymatic assays on complex biomass. Several enzymes with higher catalytic efficiencies on a wider range of model substrates than previously characterized fungal GEs were identified. Similarities and differences regarding substrate specificity between the investigated GEs were observed and putatively linked to their positioning in the CE15 phylogenetic tree. The bacterial GEs were able to utilize substrates lacking 4-OH methyl substitutions, known to be important for fungal enzymes. In addition, certain bacterial GEs were able to efficiently cleave esters of galacturonate, a functionality not previously described within the family. The two solved structures revealed similar overall folds to known structures, but also indicated active site regions allowing for more promiscuous substrate specificities. The gene expression analysis demonstrated that bacterial GE-encoding genes were differentially expressed as response to different carbon sources. Further, improved enzymatic saccharification of milled corn cob by a commercial lignocellulolytic enzyme cocktail when supplemented with GEs showcased their synergistic potential with other enzyme types on native biomass. Conclusions Bacterial GEs exhibit much larger diversity than fungal counterparts. In this study, we significantly expanded the existing knowledge on CE15 with the in-depth characterization of ten bacterial GEs broadly spanning the phylogenetic tree, and also presented two novel enzyme structures. Variations in transcriptional responses of CE15-encoding genes under different growth conditions suggest nonredundant functions for enzymes found in species with multiple CE15 genes and further illuminate the importance of GEs in native lignin–carbohydrate disassembly.
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| 3. |
- Mazurkewich, Scott, 1982, et al.
(författare)
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Biochemical and structural investigation of the CE15 family: Glucuronoyl esterases acting on recalcitrant biomass
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Glucuronoyl esterases (GEs) are a relatively new class of enzymes which cleave ester linkages between lignin and glucuronoxylan. GEs have been identified in many biomass-degrading microbes and are now classified into the Carbohydrate Esterase Family 15 (CE15). The CE15 family is diverse (as low as 20% sequence identity), however to-date only a few GEs from a small clade of the CE15 phylogenetic tree have been biochemically characterized and only two protein structures have been solved. To investigate the diversity of CE15 members, we have studied a broad range of proteins from across the phylogenetic tree. Enzymes were biochemically characterized and three-dimensional structures for two of the enzymes were solved. Analysis of the structures suggest possible binding sites for lignin fragments and xylooligosaccharides that have not been previously reported. Investigations into the molecular determinants supporting the potential binding sites is being pursued.
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