Molecular mechanisms controlling feeding state-dependent behavioral choice in zebrafish

Animals need to switch behavioral strategies to adapt to changing environmental conditions. The ability to choose the most advantageous response to a situation is crucial for survival. These decisions are influenced by environmental factors and internal signals such as physiological needs. During foraging behavior, larval zebrafish approach potential preys and avoid potential predators. The choice is influenced by external factors, such as the size of the object they are interacting with: small visual stimuli are perceived as preys while large objects are considered predators. Moreover, it was previously shown that behavioral choice during feeding behavior is modulated by metabolic state: food-deprived larvae are more likely to take risks during hunting and approach small, prey-like objects compared to fed fish. It was also demonstrated that this modulation is mediated by a differential processing of visual stimuli. In zebrafish the visual information is relayed from the retina to a midbrain structure, the optic tectum, where sensory inputs are integrated. Distinct downstream motor centers are subsequently activated to perform either an approach or an escape. This makes the optic tectum a major center for decision-making. In food-deprived larvae, tectal neurons respond preferentially to small visual stimuli compared to fed siblings, showing a shift of the tuning towards cues important for survival. These results suggest feeding induces a change in the excitability of tectal neurons to modulate behavioral choice, however the molecular mechanisms underlying this phenomenon are still unclear. To fill the gap by investigating the molecular pathways mediating the influence of metabolic state on behavioral choice, a proteomic study was performed to identify proteins differentially abundant in fed versus food-deprived larvae. Among all the hits, an especially interesting candidate was selected: a small peptide known to modulate neuronal excitability, Pcp4a, which was less abundant in fed larvae compared to food-deprived fish. pcp4a mRNA levels were also found to be lower in brain samples from fed larvae, suggesting that feeding modulates its expression through a transcriptional mechanism. PCP4, the mammalian ortholog of Pcp4a is known to bind to calmodulin, a molecule involved in several processes during neuronal activation, and to inhibit its target enzymes such as CaMKII. This results in modulation of neuron excitability in vivo. Since pcp4a is expressed in the optic tectum in zebrafish, we hypothesized that it may play a role in the regulation of tectal neurons excitability by feeding state. To test this hypothesis, I first looked at the role of pcp4a in the modulation of behavioral choice by feeding state using a loss-of-function model. Food-deprived larvae lacking Pcp4a show increased avoidance of small objects in a size discrimination assay, thus phenocopying behavioral choice of fed larvae. To understand if the effect was due to modulation of tectal neurons excitability, I investigated the response to visual stimuli of different size in tectal neurons expressing pcp4a (pcp4a+). Tectal pcp4a+ neurons in fed larvae responded preferentially to large objects compared to starved siblings; the same response profile was observed in larvae lacking Pcp4a, suggesting that Pcp4a mediates the effect of feeding on tectal neurons excitability. I then looked into the neuromodulatory mechanisms mediating the influence of metabolic signals on pcp4a expression. I found that feeding increased activity of dopaminergic neurons in the pretectum and hypothalamus, which could exert an effect on tectal pcp4a+ neurons through their direct and indirect projections to the optic tectum. Indeed, pharmacological activation of dopaminergic signaling through D2 receptors decreased pcp4a expression in food-deprived larvae, mimicking the effect of feeding. Dopamine controls pcp4a transcription through the D2 receptor - cAMP signaling cascade. Pharmacological activation of dopaminergic signaling induced a shift of the response profile of pcp4a+ tectal neurons towards large stimuli by altering the tuning properties of individual neurons. In this study we elucidate a novel molecular mechanism mediating the effect of metabolic state on behavioral choice in zebrafish. In our model, feeding activates dopaminergic neurons in the pretectum and hypothalamus, which project to the optic tectum. Dopaminergic signaling through D2 receptors induces a decrease of pcp4a expression through a transcriptional mechanism, which results in a shift of the response profile of pcp4a+ tectal neurons towards large visual stimuli through a cell-autonomous mechanism. This ultimately leads to increased avoidance of small stimuli during foraging behavior. This study advances our knowledge of the molecular mechanisms mediating neuromodulation of decision-making behavior

NEWS PRESS RELEASES IN DIGITAL ENVIRONMENTS: A contrastive genre and corpus-based approach to promoting inclusiveness within two LGBT+ organizations

Press releases as a genre can be seen as a pre-formulation device for news reports, highlighting the relationship emerging between press release writers and journalists (Jacobs 1999). Within genre studies (Swales 1990; Bhatia 1993), company press releases have been shown to exhibit a set of standard moves and strategies (McLaren, Gurau 2005), which reveal their hybrid nature resulting from the tension between informative and promotional goals (Catenaccio 2008). However, the status of the press release as a genre has been questioned due to a continuous variation in stage combinations and communicative purposes (Lassen 2006). Digital technologies have also challenged the textual structure and the participation framework of the genre (Catenaccio 2008). This paper concentrates on non-profit organizations and examines the language and features of a pilot corpus of online news press releases retrieved from the webpages of a British LGBT+ charity (Stonewall) and of its closest Italian counterpart, the Italian LGBT+ organization Arcigay. From a genre perspective, the results suggest recourse to the same (recursive) rhetorical moves, which serve informative purposes and, crucially, are primarily promotional and persuasive in nature. Additionally, based on the corpus-informed analysis, investigation into the collocational patterns of selected top lexical keywords for each corpus (vis-à-vis EnTenTen20 and ItTenTen20), as well as their concordances, showed that both organizations presented themselves as cohesive and committed communities promoting inclusiveness, and supporting LGBT+ people and communities, which are discursively framed as threatened by homo-bi-transphobic violence

Pseudosmittia fabioi sp. n., a new species from Sardinia (Diptera: Chironomidae, Orthocladiinae)

A new species of Pseudosmittia Edwards 1932, P. fabioi, from Sardinia (Palearctic region), is described and figured as male and female. The generic diagnosis is emended based on characters found in the new species. The species is characterized by a triangular anal point with microtrichia at apex (not projecting beyond tergite IX), an inferior volsella characterized by a rounded lobe with a setose accessory lobe adpressed to the gonocoxite, a well developed tooth-like projection on the outer margin of the gonostylus, the lack of acrostichals and an antenna with 6 flagellomeres in female

Implementazione della Direttiva Quadro sulle acque (2000/60/CE) attraverso l'utilizzo dei macroinvertebrati bentonici.

Lo studio si concentra sullo studio della fauna a macroinvertebrati, per definire, attraverso l\u2019utilizzo del macrobentos, lo stato/potenziale ecologico di alcuni corpi lacustri, come richiesto dalla Direttiva 2000/60/CE. Campioni biologici, di granulometria e chimica delle acque e dei sedimenti sono stati prelevati in 10 laghi appartenenti a due regioni italiane (Piemonte e Sardegna) seguendo il protocollo di campionamento nazionale. Ai dati biologici sono stati applicati indici di diversit\ue0, di equitabilit\ue0 e di ricchezza: questi mostrano che i laghi naturali presentano una comunit\ue0 pi\uf9 eterogenea rispetto agli invasi. Le analisi statistiche (generalized linear mixed effect model e multivariata) applicate ai dati biologici e abiotici mostrano che l\u2019ossigeno \ue8 il fattore che maggiormente influenza la comunit\ue0, ma \ue8 comunque l\u2019insieme di pi\uf9 fattori a determinare la densit\ue0 e la diversit\ue0 di comunit\ue0, infatti anche la tipologia di sedimento influenza la ricchezza in specie di questi ambienti. L\u2019applicazione dell\u2019Indice di Qualit\ue0 Bentonico ha inoltre permesso di evidenziare una buona separazione tra laghi profondi con scarso e buon contenuto di ossigeno a livello del fondo, e di fissare i valori di riferimento delle diverse classi di qualit\ue0 ecologica secondo le richieste della Direttiva Acque. Questo ha quindi permesso ai macroinvertebrati di essere inseriti nel Decreto Classificazione (D. M. 260/2010). Le prime applicazioni del metodo Lake Habitat Survey, utile ai fini di una classificazione idro-morfologica degli ambienti lacustri, mostrano l\u2019esistenza di correlazioni tra questo metodo e la composizione della comunit\ue0 a macroinvertebrati

News press releases in digital environments. A contrastive genre and corpus-based approach to promoting inclusiveness within two LGBT+ organizations

Press releases as a genre can be seen as a pre-formulation device for news reports, highlighting the relationship emerging between press release writers and journalists (Jacobs 1999). Within genre studies (Swales 1990; Bhatia 1993), company press releases have been shown to exhibit a set of standard moves and strategies (McLaren, Gurau 2005), which reveal their hybrid nature resulting from the tension between informative and promotional goals (Catenaccio 2008). However, the status of the press release as a genre has been questioned due to a continuous variation in stage combinations and communicative purposes (Lassen 2006). Digital technologies have also challenged the textual structure and the participation framework of the genre (Catenaccio 2008). This paper concentrates on non-profit organizations and examines the language and features of a pilot corpus of online news press releases retrieved from the webpages of a British LGBT+ charity (Stonewall) and of its closest Italian counterpart, the Italian LGBT+ organization Arcigay. From a genre perspective, the results suggest recourse to the same (recursive) rhetorical moves, which serve informative purposes and, crucially, are primarily promotional and persuasive in nature. Additionally, based on the corpus-informed analysis, investigation into the collocational patterns of selected top lexical keywords for each corpus (vis-à-vis EnTenTen20 and ItTenTen20), as well as their concordances, showed that both organizations presented themselves as cohesive and committed communities promoting inclusiveness, and supporting LGBT+ people and communities, which are discursively framed as threatened by homo-bi-transphobic violence

Regularização Fundiária Plena contra a exclusão socioterritorial : o caso do Plano Diretor de Ordenamento Territorial de 2009 do Distrito Federal

Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Instituto de Ciência Política, 2016.Este trabalho assume como tema de discussão teórica as intersecções entre cidadania e posição no espaço urbano, compreendidas entre os temas de democracia e desigualdades, centrais à ciência política contemporânea. Como referencial conceitual de análise, se valerá prioritariamente do conceito de território, compreendendo o espaço em sua dimensão política e limítrofe, na qual se destaca a divisão entre cidade e favela, tanto simbólica quanto material, e composta em gradientes e circuitos de legitimação dos espaços, suas práticas e seus habitantes

Protocollo di campionamento ed analisi granulometrica di sedimenti lacustri

No abstract availableI sedimenti, la loro origine, la loro distribuzione, e l\u27analisi della loro tessitura di un lago svolgono un ruolo importante per i macroinvertebrati in quanto forniscono utili indicazioni sull\u27assenza di determinate famiglie quando troppo grossolani e sulla presenza di altre quando fini. Il documento vuole fornire agli operatori in campo ambientale una guida al loro campionamento e all\u27analisi dimensionale a supporto delle analisi biologiche condotte in parallelo ad esse. Dal confronto analisi biologica-analisi tessiturale risulter? pi? facile argomentare la distribuzione in specie e la diversa composizione delle comunit? lacustri

Feeding on the roof of the world: the first gut content analysis of very high altitude Plecoptera

The biology of Plecoptera from high altitude Himalayan freshwaters is almost unknown. Very few and sporadic studies have been devoted to these insects, and exclusively with a taxonomic approach. We provide information on the feeding of Capnia nymphs from three lakes localized above 4,800 m a.s.l. (NE Nepal). Nymphs from these high altitude lakes feed mainly on fine detritus, acting as collector- gatherers, with the accidental ingestion of mineral matter, mostly in larger specimens. It is likely that the harsh environmental conditions in our study area create an environment unfavorable to both the allochthonous input of coarse particulate organic matter (such as terrestrial leaves) and the autochthonous input related to aquatic primary productivity, so that these nymphs feed on small organic particles that originates mainly from the catchment

Which future for Italian high altitude lakes?

Abstract: High altitude lakes and their fauna are one of the most threatened and less investigated ecosystems in Italy. Alpine lakes are highly influenced by climate harshness and by air pollution, and because of their small dimensions are extremely vulnerable to global climate warming. Italy, in addition to the Alps, hosts another mountain range: the Apennines, reaching in some cases comparable altitudes, and therefore subject to the same risks. Moreover, the gentler slope of the Apennines makes them extremely vulnerable even to direct human impacts. In the present work, for the first time, high altitude lakes belonging to the Alps and to the Apennines are compared to highlight which meteo-climatic or chemical characteristics could be considered key drivers for their macrinvertebrate structure. The study area was explicitly focused on natural lakes placed above 1300 m of altitude and above the 44° parallel, thus in the alpine area and subject to a continental climate. 25 lakes were chosen (19 in the central-western Alps and 6 in the Modenese Apennines) with surface areas lower than 1 km2 and with maximum depths lower than 15 m. Physico-chemical parameters and macroinvertebrates were studied and compared. Samples were taken through the use of an hand-net (250 μm mesh size) along the littorals on different substrates following standardised methodologies during the richerfauna season to allow an easier identification of species. Parallel to that, water samples were collected and analysed. Species richness and the Taxonomic Distinctness Indices were applied to underline the different complexity of the community structure of the two areas. Results showed different macroinvertebrates communities with peculiar characteristics and highlighted a more structured and diverse composition on the Apennines. Predictive models on the future climate scenarios show how the peninsular portion of Italy will be even more affected by the increase in temperatures than the Alpine area. Thus, this work could be highly informative, mainly for central Italy, where proximity to towns encourage tourists to reach these type of lakes, even if placed in protected areas or parks. Therefore, protection and management plans, and conservation efforts of high altitudes cannot overlooked a thorough understanding of the biological diversity of these environments, which still appears fragmented and limited to some sector of the Alps. Furthermore, the fundamental role of high altitude lakes as water resource needs a specific management regime, as they are not included under the monitoring programs of the Water Framework Directive legislation