| 1. |
- Allassonnière-Tang, Marc, et al.
(author)
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Expansion by migration and diffusion by contact is a source to the global diversity of linguistic nominal categorization systems
- 2021
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In: Humanities & Social Sciences Communications. - : Springer Science and Business Media LLC. - 2662-9992. ; 8, s. 1-6
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Journal article (peer-reviewed)abstract
- Languages of diverse structures and different families tend to share common patterns if they are spoken in geographic proximity. This convergence is often explained by horizontal diffusibility, which is typically ascribed to language contact. In such a scenario, speakers of two or more languages interact and influence each other’s languages, and in this interaction, more grammaticalized features tend to be more resistant to diffusion compared to features of more lexical content. An alternative explanation is vertical heritability: languages in proximity often share genealogical descent. Here, we suggest that the geographic distribution of features globally can be explained by two major pathways, which are generally not distinguished within quantitative typological models: feature diffusion and language expansion. The first pathway corresponds to the contact scenario described above, while the second occurs when speakers of genetically related languages migrate. We take the worldwide distribution of nominal classification systems (grammatical gender, noun class, and classifier) as a case study to show that more grammaticalized systems, such as gender, and less grammaticalized systems, such as classifiers, are almost equally widespread, but the former spread more by language expansion historically, whereas the latter spread more by feature diffusion. Our results indicate that quantitative models measuring the areal diffusibility and stability of linguistic features are likely to be affected by language expansion that occurs by historical coincidence. We anticipate that our findings will support studies of language diversity in a more sophisticated way, with relevance to other parts of language, such as phonology.
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| 2. |
- Allwood, Jens, 1947, et al.
(author)
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Work on Spoken (Multimodal) Corpora in South Africa.
- 2010
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In: Calzolari, N, Choukri, K. Maegaard, B, Mariani, J., Odijk, J, Piperidis, S, Rosner, M. & Tapias, D. (Eds.) Proceedings of the Seventh conference on International Language Resources and Evaluation (LREC'10) Valetta, Malta May 19-21. European Language Resources Association (ELRA). http://www.lrec-conf.org/proceedings/lrec2010/index.html (ALLWOOD 10.438).. - 2951740867
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Conference paper (peer-reviewed)
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| 3. |
- Allwood, Jens, et al.
(author)
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Work on Spoken (Multimodal) Language Corpora in South Africa
- 2010
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Conference paper (peer-reviewed)abstract
- This paper describes past, ongoing and planned work on the collection and transcription of spoken language samples for all the South African official languages and as part of this the training of researchers in corpus linguistic research skills. More specifically the work has involved (and still involves) establishing an international corpus linguistic network linked to a network hub at a UNISA website and the development of research tools, a corpus research guide and workbook for multimodal communication and spoken language corpus research. As an example of the work we are doing and hope to do more of in the future, we present a small pilot study of the influence of English and Afrikaans on the 100 most frequent words in spoken Xhosa as this is evidenced in the corpus of spoken interaction we have gathered so far. Other planned work, besides work on spoken language phenomena, involves comparison of spoken and written language and work on communicative body movements (gestures) and their relation to speech.
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| 4. |
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| 5. |
- Almstedt, Karin, 1980-, et al.
(author)
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Unfolding a folding disease: folding, misfolding and aggregation of the marble brain syndrome-associated mutant H107Y of human carbonic anhydrase II
- 2004
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In: Journal of Molecular Biology. - Oxford : Elsevier. - 0022-2836 .- 1089-8638. ; 342:2, s. 619-633
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Journal article (peer-reviewed)abstract
- Most loss-of-function diseases are caused by aberrant folding of important proteins. These proteins often misfold due to mutations. The disease marble brain syndrome (MBS), known also as carbonic anhydrase II deficiency syndrome (CADS), can manifest in carriers of point mutations in the human carbonic anhydrase II (HCA II) gene. One mutation associated with MBS entails the His107Tyr substitution. Here, we demonstrate that this mutation is a remarkably destabilizing folding mutation. The loss-of-function is clearly a folding defect, since the mutant shows 64% of CO2 hydration activity compared to that of the wild-type at low temperature where the mutant is folded. On the contrary, its stability towards thermal and guanidine hydrochloride (GuHCl) denaturation is highly compromised. Using activity assays, CD, fluorescence, NMR, cross-linking, aggregation measurements and molecular modeling, we have mapped the properties of this remarkable mutant. Loss of enzymatic activity had a midpoint temperature of denaturation (Tm) of 16 °C for the mutant compared to 55 °C for the wild-type protein. GuHCl-denaturation (at 4 °C) showed that the native state of the mutant was destabilized by 9.2 kcal/mol. The mutant unfolds through at least two equilibrium intermediates; one novel intermediate that we have termed the molten globule light state and, after further denaturation, the classical molten globule state is populated. Under physiological conditions (neutral pH; 37 °C), the His107Tyr mutant will populate the molten globule light state, likely due to novel interactions between Tyr107 and the surroundings of the critical residue Ser29 that destabilize the native conformation. This intermediate binds the hydrophobic dye 8-anilino-1-naphthalene sulfonic acid (ANS) but not as strong as the molten globule state, and near-UV CD reveals the presence of significant tertiary structure. Notably, this intermediate is not as prone to aggregation as the classical molten globule. As a proof of concept for an intervention strategy with small molecules, we showed that binding of the CA inhibitor acetazolamide increases the stability of the native state of the mutant by 2.9 kcal/mol in accordance with its strong affinity. Acetazolamide shifts the Tm to 34 °C that protects from misfolding and will enable a substantial fraction of the enzyme pool to survive physiological conditions.
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| 6. |
- Babu Moparthi, Satish, et al.
(author)
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Differential conformational modulations of MreB folding upon interactions with GroEL/ES and TRiC chaperonin components
- 2016
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In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 6:28386
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Journal article (peer-reviewed)abstract
- Here, we study and compare the mechanisms of action of the GroEL/GroES and the TRiC chaperonin systems on MreB client protein variants extracted from E. coli. MreB is a homologue to actin in prokaryotes. Single-molecule fluorescence correlation spectroscopy (FCS) and time-resolved fluorescence polarization anisotropy report the binding interaction of folding MreB with GroEL, GroES and TRiC. Fluorescence resonance energy transfer (FRET) measurements on MreB variants quantified molecular distance changes occurring during conformational rearrangements within folding MreB bound to chaperonins. We observed that the MreB structure is rearranged by a binding-induced expansion mechanism in TRiC, GroEL and GroES. These results are quantitatively comparable to the structural rearrangements found during the interaction of beta-actin with GroEL and TRiC, indicating that the mechanism of chaperonins is conserved during evolution. The chaperonin-bound MreB is also significantly compacted after addition of AMP-PNP for both the GroEL/ES and TRiC systems. Most importantly, our results showed that GroES may act as an unfoldase by inducing a dramatic initial expansion of MreB (even more than for GroEL) implicating a role for MreB folding, allowing us to suggest a delivery mechanism for GroES to GroEL in prokaryotes.
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| 7. |
- Babu Moparthi, Satish, et al.
(author)
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Transient conformational remodeling of folding proteins by GroES - Individually and in concert with GroEL
- 2014
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In: Journal of chemical biology. - : Springer Berlin/Heidelberg. - 1864-6158 .- 1864-6166. ; 7:1, s. 1-15
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Research review (peer-reviewed)abstract
- The commonly accepted dogma of the bacterial GroE chaperonin system entails protein folding mediated by cycles of several ATP-dependent sequential steps where GroEL interacts with the folding client protein. In contrast, we herein report GroES-mediated dynamic remodeling (expansion and compression) of two different protein substrates during folding: the endogenous substrate MreB and carbonic anhydrase (HCAII), a well-characterized protein folding model. GroES was also found to influence GroEL binding induced unfolding and compression of the client protein underlining the synergistic activity of both chaperonins, even in the absence of ATP. This previously unidentified activity by GroES should have important implications for understanding the chaperonin mechanism and cellular stress response. Our findings necessitate a revision of the GroEL/ES mechanism.
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| 8. |
- Barbieri, Chiara, et al.
(author)
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A global analysis of matches and mismatches between human genetic and linguistic histories
- 2022
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In: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 119:47
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Journal article (peer-reviewed)abstract
- Human history is written in both our genes and our languages. The extent to which our biological and linguistic histories are congruent has been the subject of considerable debate, with clear examples of both matches and mismatches. To disentangle the patterns of demographic and cultural transmission, we need a global systematic assessment of matches and mismatches. Here, we assemble a genomic database (GeLaTo, or Genes and Languages Together) specifically curated to investigate genetic and linguistic diversity worldwide. We find that most populations in GeLaTo that speak languages of the same language family (i.e., that descend from the same ancestor language) are also genetically highly similar. However, we also identify nearly 20% mismatches in populations genetically close to linguistically unrelated groups. These mismatches, which occur within the time depth of known linguistic relatedness up to about 10,000 y, are scattered around the world, suggesting that they are a regular outcome in human history. Most mismatches result from populations shifting to the language of a neighboring population that is genetically different because of independent demographic histories. In line with the regularity of such shifts, we find that only half of the language families in GeLaTo are genetically more cohesive than expected under spatial autocorrelations. Moreover, the genetic and linguistic divergence times of population pairs match only rarely, with Indo-European standing out as the family with most matches in our sample. Together, our database and findings pave the way for systematically disentangling demographic and cultural history and for quantifying processes of shifts in language and social identities on a global scale.
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