75 research outputs found
The Hamar cattle model: the semantics of appearance in a pastoral linguaculture
NWOVI.Veni.191T.026Descriptive and Comparative Linguistic
Existential predication in Hamar
This paper analyzes predicative constructions expressing location, existence and possession in Hamar, a South Omotic language spoken in South-West Ethiopia. The semantic domain location-existence-possession is conveyed in Hamar by one and the same lexeme, but in different constructions. The distinction between location and existence in particular is expressed by variation in the syntax and information structure, reflecting the different conceptualization and perspectivization of the abstract relation between a figure and a ground. The semantic and syntactic properties of these constructions are analyzed and compared to the findings of Creissels’ typology of “inverse locational predication” (2013) and Koch’s constructional typology (2012). The analysis of existential predication in Hamar confirms that there is a contrast between the languages of the Sudanic belt and those of North Eastern Sub-Saharan Africa (Creissels 2018a; 2019), and it suggests that Hamar, like other Afro-Asiatic languages (Koch 2012:585), belongs to languages which do not express informational salience, nor propositional salience. A closer look however reveals that Hamar existential constructions display special morpho-syntactic features: the different conceptualization of the figure-ground relationship is encoded not only by means of word order alternations, but also by means of gender marking on the figure and the ground, and different aspectual marking on the predicator.Descriptive and Comparative Linguistic
STUDIO SUL RUOLO DELL’ACIDO Δ1-PIRROLIN-5-CARBOSSILICO NEI FENOMENI DI TOSSICITÀ INDOTTA DA PROLINA IN ARABIDOPSIS THALIANA.
A high accumulation of proline due to increased synthesis and decreased degradation under a variety of stress conditions, such as salt, drought and metals, has been documented in many plant species (Kavi Kishor et al., 2005). This accumulation (up to 80% of total free amino acids under stress, compared to 5% under normal conditions) seems to have diverse physiological roles, such as acting as a compatible osmolyte for osmotic adjustment, stabilization of proteins, membranes and subcellular structures, buffering cellular redox potential and protecting cellular functions by scavenging reactive oxygen species (ROS) (Kavi Kishor et al., 2005; Ashraf and Foolad, 2007).
In plants, proline is synthesized from either glutamate or ornithine (Kavi Kishor et al.,2005; Ashraf and Foolad, 2007). The first two steps of proline biosynthesis from glutamate are catalyzed by a single bifunctional enzyme, δ1-pyrroline-5-carboxylate synthetase (P5CS), yielding glutamic-γ-semialdehyde (GSA). GSA spontaneously cyclises into pyrroline-5-carboxylate (P5C), that is reduced in turn by P5C reductase (P5CR) to proline (Zhang et al., 1995; Kavi Kishor et al., 2005). Plants also synthesize proline from ornithine, through the activity of ornithine-δ-aminotransferase (δOAT) that transaminates ornithine directly to GSA, which is subsequently converted to proline via P5C (Kavi Kishore et al., 2005). The onset of stress-induced proline accumulation is correlated with transcriptional activation of the gene encoding P5CS, which is believed to represent the key and rate limiting enzyme in this biosynthetic pathway (Stines et al., 1999; Zhang et al., 2008).
During recent years a thorough understanding of the mechanisms underlying regulation of Pro biosynthesis has been achieved. However, the role of the catabolic pathway it is still unclear, consisting of two steps sequentially catalyzed by a Pro- and a P5C-dehydrogenase (DH). The oxidative pathway is induced by high intracellular levels of the imino acid; such induction is prevented under hyperosmotic stress conditions (Verbruggen et al., 1996).
Besides its obvious role in Pro recycling after the re-establishment of normo-osmotic conditions, no other physiological roles have been up to now identified for the catabolic pathway. Actually, Arabidopsis thaliana knock-out seedlings for either Pro-DH1 or P5C-DH are morphologically undistinguishable from the wild type and show a normal life cycle. The main effect of the impairment of proline catabolism appears to be a hypersensitivity to the amino acid or to its analogues (Deuschle et al., 2004 ; Mani et al., 2002). Indeed, an unexpected result is that an exogenous Pro supply apparently causes phytotoxic effects. Besides necrotic area formation, the production of reactive oxygen species (ROS) and DNA laddering have been reported (Deuschle et al., 2004 ), suggesting the onset of programmed cell death (PCD). In animal systems it is well known that the PRODH gene is early induced by the tumor suppressor protein p53 (Maxwell et al., 2000), that may inhibit growth and trigger PCD; exogenously-supplied P5C may also cause apoptosis. P5CDH was also reported to represent a p53 target, but it seems able to protect cells from oxidative stress and inhibit cell death (Yoon et al., 2004). Human Pro-DH appears to catalyse ROS production directly, depending to substrate availability (Donald et al.,2001), but Pro-DH has never been purified and fully characterized to date from any plant species.
On the other hand, an early induction of the gene for P5C-DH has been found in crops undergoing a fungal attack, a response typically observed in the case of compatible interactions (Roberts et al., 1995; Ayliffe et al., 2002). Moreover, Pro accumulation through activation of the biosynthetic pathway has been recently shown in Arabidopsis during incompatible plant-pathogen interactions (Fabro et al., 2004). Thus the possibility exists that Pro metabolism is involved in processes leading to PCD during the hypersensitive reaction. Proline effects have been proposed to be mediated by P5C (Phang et al.,1985; Deuschle et al.,2004 ). However, this seems inconsistent with the severe toxicity that occurs in prod1- mutants and plants expressing antisense ProDH constructs (Mani et al., 2002; Nanjo et al., 2003 ).
P5C is the common metabolic intermediate in proline synthesis and catabolism. It is also produced by δOAT, which was recently demonstrated to be localized in the mitochondria (Funck et al., 2008). It is still a matter of debate whether the P5C produced by Arg/Orn catabolism enters proline biosynthesis directly, or it is metabolized to glutamate by mitochondrial P5CDH. Funck and coworkers showed experimental evidence supporting the latter hypothesis. Consistently, the occurrence of a specific P5C transporter has never been reported. This notwithstanding, some authors postulated that P5C can pass the mitochondrial membrane, and that a P5C/Pro cycle mediated by ProDH and P5CR activity can occur (Hu et al., 2007; Miller et al., 2009). Since P5C/Pro cycling is believed to cause ROS production, P5C oxidation by P5CDH would be essential for limiting cycle activity and avoiding ROS-induced damage (Miller et al., 2009).
In Arabidopsis thaliana a single gene is present for both enzymes utilizing P5C as a substrate, namely P5CR and P5CDH. Until now, neither gene product has been purified in this species. Moreover, no obvious correlations between mRNA and protein levels and a RNA silencing-based regulatory mechanism were described for P5CR and P5CDH, respectively. The P5CR mRNA contains a non-coding region in the 5’ untranslated region (UTR) that at the same time mediates transcript stabilization and translation inhibition during salt and heat stress (Hua et al., 2001). Arabidopsis P5CDH has been found to be associated with another gene, which is partially overlapping on the complementary strand. The transcription of this gene is up-regulated under salt stress conditions, with a consequent production and processing of dsRNA. Short interfering RNA being able to downregulate P5CDH are generated from this process (Borsani et al., 2005).
Although many physiological studies suggested that proline may be implicated in multiple stress protection mechanisms, it is also evident that proline accumulation does not represent a response conferring tolerance per se. Accordingly, several salt- and cold-hypersensitive Arabidopsis mutants accumulate proline at high levels without any apparent beneficial effect on stress tolerance (Liu and Zhu, 1997). Therefore, a proper understanding of how proline accumulation influences particular regulatory pathways in complex stress responses still requires many efforts (Maggio et al., 2002).
Aiming at a better comprehension of the role of proline in plant stress response, Arabidopsis was selected as the experimental system. In this weed, P5CDH and P5CR are present as single genes, a feature that may simplify the analysis of expression patterns. Moreover, the availability of a lot of molecular data as well as the fully sequenced genome provide useful tools for the investigation. However, proper evaluations would be hampered in planta by the small size of Arabidopsis seedlings, a drawback that most likely explains why the proteins involved in proline metabolism have not been purified to date. On the other side, in differentiated plants inter-tissue transport, exclusion mechanisms and cell compartmentalization of proline do occur. As a consequence, it is difficult to know the exact conditions (i.e., ionic vs osmotic, extra- and intracellular concentrations, pressure values) to which a single cell is exposed. The availability of suitable experimental systems to quantify resistance to realistic and reproducible low water potential, or salt and freezing stress conditions is well recognized as a crucial point in genetic studies (Verslues et al., 2006). Suspension cultured cells may represent one of these systems. The possibility of using p5cdh seeds, kindly provided by Dr Dietmar Funck (Konstanz, Germany), was a further stimulus to establish cell suspension cultures from A. thaliana seedlings. Two well dispersed cultures were obtained, and used to evaluate cell responses to various experimental conditions, mainly focusing on the metabolic role of the possible effector of Pro toxicity, P5C
A grammar of Hamar : a South Omotic language of Ethiopia
This study is the first-ever attempt at a comprehensive grammatical description of Hamar, a language spoken in South West Ethiopia by approximately 46.500 people. The study is based on 9 months of fieldwork carried out between 2012 and 2014 in Hamar territories. Language data was gathered from 14 native speakers in Hamar villages, and it amounts to 50 texts of varying lengths and genres. The grammar investigates the phonology, the morphology, the syntax and some pragmatic and discourse related features of Hamar and it is organized in 13 chapters followed by three appendices: appendix A and B consist of a selected lexicon of circa 1400 entries, appendix C includes three annotated Hamar texts.
Hamar is a fascinating language and it has revealed unique typological features: the noun classification system of Hamar for instance is a rare example of ʻnon-fixedʼ gender system, i.e. a system in which gender is not an inherent property of nouns, but optional. The grammar is of interests to typologists but also to linguists interested in comparative Afro-Asiatic studies: the grammar offers an overview of the classificatory issue of Hamar and South Omotic languages, and it includes an updated comparative list of South Omotic lexicon.
Labex ASLAN, Université de Lyon (Agence Nationale de la Recherce)Language Use in Past and Presen
Essays on African languages and linguistics : in honour of Maarten Mous
This book celebrates Maarten Mous, professor of African Linguistics at Leiden University. For many people engaged in the field of African linguistics (and beyond), Maarten has been a teacher, an engaged colleague, and an inspiration. On the occasion of his 65th birthday, the present volume offers essays written by his former and current PhD students. The volume is divided into four sections: Language in use and contact, Morphosyntax, Number and numerals, and Phonology. It contains 25 articles and presents a variety of disciplinary and regional approaches to African linguistics.bookDescriptive and Comparative Linguistic
FAIRification of LeiLanD
peer reviewedLeiLanD (Leiden Language Data) is a searchable catalogue initiated by the Leiden University Centre for Linguistics (LUCL) with the support of CLARIAH. The catalogue contains metadata about language datasets collected at LUCL and other institutes of Leiden University. This paper describes a project to FAIRify the datasets increasing their findability and accessibility through a standardised metadata format CMDI so as to obtain a rich metadata description for all resources and to make them findable through CLARIN's Virtual Language Observatory. The paper describes the creation of the catalogue and the steps that led from unstructured metadata to CMDI standards. This FAIRification of LeiLanD has enhanced the findability and accessibility of highly diverse collection of language datasets
Theory and description in African Linguistics: Selected papers from the 47th Annual Conference on African Linguistics
The papers in this volume were presented at the 47th Annual Conference on African Linguistics at UC Berkeley in 2016. The papers offer new descriptions of African languages and propose novel theoretical analyses of them. The contributions span topics in phonetics, phonology, syntax, semantics, and pragmatics and reflect the typological and genetic diversity of languages in Africa. Four papers in the volume examine Areal Features and Linguistic Reconstruction in Africa, and were presented at a special workshop on this topic held alongside the general session of ACAL
Theory and description in African Linguistics: Selected papers from the 47th Annual Conference on African Linguistics
The papers in this volume were presented at the 47th Annual Conference on African Linguistics at UC Berkeley in 2016. The papers offer new descriptions of African languages and propose novel theoretical analyses of them. The contributions span topics in phonetics, phonology, syntax, semantics, and pragmatics and reflect the typological and genetic diversity of languages in Africa. Four papers in the volume examine Areal Features and Linguistic Reconstruction in Africa, and were presented at a special workshop on this topic held alongside the general session of ACAL
Theory and description in African Linguistics: Selected papers from the 47th Annual Conference on African Linguistics
The papers in this volume were presented at the 47th Annual Conference on African Linguistics at UC Berkeley in 2016. The papers offer new descriptions of African languages and propose novel theoretical analyses of them. The contributions span topics in phonetics, phonology, syntax, semantics, and pragmatics and reflect the typological and genetic diversity of languages in Africa. Four papers in the volume examine Areal Features and Linguistic Reconstruction in Africa, and were presented at a special workshop on this topic held alongside the general session of ACAL
Theory and description in African Linguistics: Selected papers from the 47th Annual Conference on African Linguistics
The papers in this volume were presented at the 47th Annual Conference on African Linguistics at UC Berkeley in 2016. The papers offer new descriptions of African languages and propose novel theoretical analyses of them. The contributions span topics in phonetics, phonology, syntax, semantics, and pragmatics and reflect the typological and genetic diversity of languages in Africa. Four papers in the volume examine Areal Features and Linguistic Reconstruction in Africa, and were presented at a special workshop on this topic held alongside the general session of ACAL
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