Hypothalamic Integration of Metabolic, Endocrine, and Circadian Signals in Fish: Involvement in the Control of Food Intake

The regulation of food intake in fish is a complex process carried out through several different mechanisms in the central nervous system (CNS) with hypothalamus being the main regulatory center. As in mammals, a complex hypothalamic circuit including two populations of neurons: one co-expressing neuropeptide Y (NPY) and Agouti-related peptide (AgRP) and the second one population co-expressing pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) is involved in the integration of information relating to food intake control. The production and release of these peptides control food intake, and the production results from the integration of information of different nature such as levels of nutrients and hormones as well as circadian signals. The present review summarizes the knowledge and recent findings about the presence and functioning of these mechanisms in fish and their differences vs. the known mammalian model

Ghrelin Facilitates GLUT2-, SGLT1- and SGLT2-mediated Intestinal Glucose Transport in Goldfish (Carassius auratus)

Glucose homeostasis is an important biological process that involves a variety of regulatory mechanisms. This study aimed to determine whether ghrelin, a multifunctional gut-brain hormone, modulates intestinal glucose transport in goldfish (Carassius auratus). Three intestinal glucose transporters, the facilitative glucose transporter 2 (GLUT2), and the sodium/glucose co-transporters 1 (SGLT1) and 2 (SGLT2), were studied. Immunostaining of intestinal sections found colocalization of ghrelin and GLUT2 and SGLT2 in mucosal cells. Some cells containing GLUT2, SGLT1 and SGLT2 coexpressed the ghrelin/growth hormone secretagogue receptor 1a (GHS-R1a). Intraperitoneal glucose administration led to a significant increase in serum ghrelin levels, as well as an upregulation of intestinal preproghrelin, ghrelin O-acyltransferase and ghs-r1 expression. In vivo and in vitro ghrelin treatment caused a concentration- and time-dependent modulation (mainly stimulatory) of GLUT2, SGLT1 and SGLT2. These effects were abolished by the GHS-R1a antagonist [D-Lys3]-GHRP-6 and the phospholipase C inhibitor U73122, suggesting that ghrelin actions on glucose transporters are mediated by GHS-R1a via the PLC/PKC signaling pathway. Finally, ghrelin stimulated the translocation of GLUT2 into the plasma membrane of goldfish primary intestinal cells. Overall, data reported here indicate an important role for ghrelin in the modulation of glucoregulatory machinery and glucose homeostasis in fish

the origin and genetic differentiation of the Manila clam (Ruditapes philippinarum) cultured in Europe

Comunicación presentada en el Aquaculture Europe 2014, celebrado en Donostia-San Sebastián, España, del 14 al 17 de octubre de 2014The Manila clam is an Asian species that was introduced in Europe in the 1970’s due to their advantageous characteristics for cultivation (Flassch and Leborgne, 1992). Currently, the Manila clam makes up the bulk of European production of clams (FAO data for 2012: 31 836 T). The species has spread over wide areas of the European coasts, either by natural reproduction, or aided by man through induced reproduction in hatcheries. A scientifically sound management of Manila clam genetic resources requires the knowledge of the genetic variability of European populations. Genetic studies (Sekine et al., 2006; Mao et al., 2011) indicate that the populations of the native range of the species in Asia are genetically subdivided, so the genetic composition of European populations would be dependent on the geographic area from which the founder stock came from. Published reports (Flassch and Leborgne 1992) claim that the first introduced clams were seeded in NW France and came from the NW Pacific coast, where, in turn, they were accidentally introduced 40 years earlier as a carry over with the seed of Pacific oyster (Crassostrea gigas) imported from Japan. Therefore, it is of great interest to know whether the clams currently living in the European coasts all come from the reported introduction of American/Japanese seed, or whether they are a mixed stock resulting from posterior, non reported introductions by clam farmers. With this aim we have conducted a genetic study of some European Manila clam populations, and compared them with samples taken form the natural range of the species in China and Japan, and from the American area of origin of the reported European founder stock.This work was supported by grant AGL2007-60049 from the National Research Plan of the Government of Spain.Peer Reviewe

Ghrelin induces clock gene expression in the liver of goldfish in vitro via protein kinase C and protein kinase A pathways

The liver is the most important link between the circadian system and metabolism. As a food-entrainable oscillator, the hepatic clock needs to be entrained by food-related signals. The objective of the present study was to investigate the possible role of ghrelin (an orexigenic peptide mainly synthesized in the gastrointestinal tract) as an endogenous synchronizer of the liver oscillator in teleosts. To achieve this aim, we first examined the presence of ghrelin receptors in the liver of goldfish. Then, the ghrelin regulation of clock gene expression in the goldfish liver was studied. Finally, the possible involvement of the phospholipase C/protein kinase C (PLC/PKC) and adenylate cyclase/protein kinase A (AC/PKA) intracellular signalling pathways was investigated. Ghrelin receptor transcripts, ghs-r1a, are present in the majority of goldfish hepatic cells. Ghrelin induced the mRNA expression of the positive (gbmal1a, gclock1a) and negative (gper genes) elements of the main loop of the molecular clock machinery, as well as grev-erbα (auxiliary loop) in cultured liver. These effects were blocked, at least in part, by a ghrelin antagonist. Incubation of liver with a PLC inhibitor (U73122), a PKC activator (phorbol 12-myristate 13-acetate) and a PKC inhibitor (chelerythrine chloride) demonstrated that the PLC/PKC pathway mediates such ghrelin actions. Experiments with an AC activator (forskolin) and a PKA inhibitor (H89) showed that grev-erbα regulation could be due to activation of PKA. Taken together, the present results show for the first time in vertebrates a direct action of ghrelin on hepatic clock genes and support a role for this hormone as a temporal messenger in the entrainment of liver circadian functions

Characterization of Ghrelin O-Acyltransferase (GOAT) in goldfish (Carassius auratus)

Ghrelin is the only known hormone posttranslationally modified with an acylation. This modification is crucial for most of ghrelin’s physiological effects and is catalyzed by the polytopic enzyme ghrelin O-acyltransferase (GOAT). The aim of this study was to characterize GOAT in a teleost model, goldfish (Carassius auratus). First, the full-length cDNA sequence was obtained by RT-PCR and rapid amplification of cDNA ends methods. Two highly homologous cDNAs of 1491 and 1413 bp, respectively, named goat-V1 and goat-V2 were identified. Deduced protein sequences (393 and 367 amino acids, respectively) are predicted to present 11 and 9 transmembrane regions, respectively, and both contain two conserved key residues proposed to be involved in catalysis: asparagine 273 and histidine 304. RT-qPCR revealed that both forms of goat mRNAs show a similar widespread tissue distribution, with the highest expression in the gastrointestinal tract and gonads and less but considerable expression in brain, pituitary, liver and adipose tissue. Immunostaining of intestinal sections showed the presence of GOAT immunoreactive cells in the intestinal mucosa, some of which colocalize with ghrelin. Using an in vitro approach, we observed that acylated ghrelin downregulates GOAT gene and protein levels in cultured intestine in a time-dependent manner. Finally, we found a rhythmic oscillation of goat mRNA expression in the hypothalamus, pituitary and intestinal bulb of goldfish fed at midday, but not at midnight. Together, these findings report novel data characterizing GOAT, and offer new information about the ghrelinergic system in fish

A Social Approach to Chagas Disease: A First Step to Improve Access to Comprehensive Care

The aim of this chapter is to provide new insights to the traditional approaches of the problematic of Chagas disease by questioning the hegemonic paradigmatic frameworks through which the topic is traditionally studied and addressed. These questionings and the proposals derived from them are supported on the evidence of an epidemiological change and entail a transformation in the way of understanding the “disease,” the “affected people,” and the diverse actors and scenarios involved in the problematic.Grupo de Didáctica de las Ciencia

Nuclear receptors (PPARs, REV-ERBs, RORs) and clock gene rhythms in goldfish (Carassius auratus) are differently regulated in hypothalamus and liver

The circadian system is formed by a network of oscillators located in central and peripheral tissues that are tightly linked to generate rhythms in vertebrates to adapt the organism to the cyclic environmental changes. The nuclear receptors PPARs, REV-ERBs and RORs are transcription factors controlled by the circadian system that regulate, among others, a large number of genes that control metabolic processes for which they have been proposed as key genes that link metabolism and temporal homeostasis. To date it is unclear whether these nuclear receptors show circadian expression and which zeitgebers are important for their synchronization in fish. Therefore, the objective of this study was to investigate whether the two main zeitgebers (light-dark cycle and feeding time) could affect the synchronization of central (hypothalamus) and peripheral (liver) core clocks and nuclear receptors in goldfish. To this aim, three experimental groups were established: fish under a 12 h light-12 h darkness and fed at Zeitgeber Time 2; fish with the same photoperiod but randomly fed; and fish under constant darkness and fed at Circadian Time 2. After one month, clock genes and nuclear receptors expression in hypothalamus and liver and circulating glucose were studied. Clock genes displayed daily rhythms in both tissues of goldfish if the light-dark cycle was present, with shifted-acrophases of negative and positive elements, as expected for proper functioning clocks. In darkness-maintained fish hypothalamic clock genes were fully arrhythmic while the hepatic ones were still rhythmic. Among studied nuclear receptors, in the hypothalamus only nr1d1 was rhythmic and only when the light-dark cycle was present. In the liver all nuclear receptors were rhythmic when both zeitgebers were present, but only nr1d1 when one of them was removed. Plasma glucose levels showed significant rhythms in fish maintained under random fed regimen or constant darkness, with the highest levels at 1-h postprandially in all groups. Altogether these results support that hypothalamus is mainly a light-entrained-oscillator, while the liver is a food-entrained-oscillator. Moreover, nuclear receptors are revealed as clear outputs of the circadian system acting as key elements in the timekeeping of temporal homeostasis, particularly in the liver

De Nueva España a México : El universo musical mexicano entre centenarios (1517-1917)

742 págs. Imágenes color y b/n. Partituras musicales.El fenómeno de las conmemoraciones culturales siempre ha sido un terreno abonado para la producción cultural y artística del que se han valido los Estados para ofrecer interpretaciones legitimadoras e ideologizadas de la historia, articuladas en torno a las ideas de memoria, nación y progreso. El presente volumen, resultado de una triple conmemoración (el centenario de la Revolución Mexicana y la publicación de la primera historia de la música en México de Alba Herrera –1917–, por un lado; y la llegada del militar andaluz Francisco Hernández de Córdoba a la costa de la península del Yucatán –1517–, por otro), presenta una visión retrospectiva de la historia musical mexicana a lo largo de esas cuatro centurias. Frente a la rígida división cronológica impuesta por ciertas narrativas, se ofrece así una noción inclusiva, actual e informada del universo musical mexicano en toda su multiplicidad y riqueza de matices, integrando las épocas colonial e independiente como lo que realmente son: partes constitutivas de la memoria musical, histórica, cultural y política del país, con las luces y las sombras propias de cualquier otro periodo

COVID-19 outbreaks in a transmission control scenario: challenges posed by social and leisure activities, and for workers in vulnerable conditions, Spain, early summer 2020

Severe acute respiratory syndrome coronavirus 2 community-wide transmission declined in Spain by early May 2020, being replaced by outbreaks and sporadic cases. From mid-June to 2 August, excluding single household outbreaks, 673 outbreaks were notified nationally, 551 active (>6,200 cases) at the time. More than half of these outbreaks and cases coincided with: (i) social (family/friends’ gatherings or leisure venues) and (ii) occupational (mainly involving workers in vulnerable conditions) settings. Control measures were accordingly applied