Neurogranin-Like Immunoreactivity in the Zebrafish Brain During Development

[Abstract] Neurogranin (Nrgn) is a neural protein that is enriched in the cerebral cortex and is involved in synaptic plasticity via its interaction with calmodulin. Recently we reported its expression in the brain of the adult zebrafish (Alba-González et al. J Comp Neurol 530:1569–1587, 2022). In this study we analyze the development of Nrgn-like immunoreactivity (Nrgn-like-ir) in the brain and sensory structures of zebrafish embryos and larvae, using whole mounts and sections. First Nrgn-like positive neurons appeared by 2 day post-fertilization (dpf) in restricted areas of the brain, mostly in the pallium, epiphysis and hindbrain. Nrgn-like populations increased noticeably by 3 dpf, reaching an adult-like pattern in 6 dpf. Most Nrgn-like positive neurons were observed in the olfactory organ, retina (most ganglion cells, some amacrine and bipolar cells), pallium, lateral hypothalamus, thalamus, optic tectum, torus semicircularis, octavolateralis area, and viscerosensory column. Immunoreactivity was also observed in axonal tracts originating in Nrgn-like neuronal populations, namely, the projection of Nrgn-like immunopositive primary olfactory fibers to olfactory glomeruli, that of Nrgn-like positive pallial cells to the hypothalamus, the Nrgn-like-ir optic nerve to the pretectum and optic tectum, the Nrgn-like immunolabeled lateral hypothalamus to the contralateral region via the horizontal commissure, the octavolateralis area to the midbrain via the lateral lemniscus, and the viscerosensory column to the dorsal isthmus via the secondary gustatory tract. The late expression of Nrgn in zebrafish neurons is probably related to functional maturation of higher brain centers, as reported in the mammalian telencephalon. The analysis of Nrgn expression in the zebrafish brain suggests that it may be a useful marker for specific neuronal circuitries.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Alba-González A. is recipient of a Predoctoral Fellowship from Xunta de Galicia (Grant number ED481A-2019/003)Xunta de Galicia; ED481A-2019/00

The organization of the zebrafish pallium from a hodological perspective

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] We studied the connections (connectome) of the adult zebrafish pallium using carbocyanine dye tracing and ancillary anatomical methods. The everted zebrafish pallium (dorsal telencephalic area, D) is composed of several major zones (medial, lateral, dorsal, central, anterior, and posterior) distinguishable by their topography, cytoarchitecture, immunohistochemistry, and genoarchitecture. Our comprehensive study reveals poor interconnectivity between these pallial areas, especially between medial (Dm), lateral/dorsal (Dl, Dd), and posterior (Dp) regions. This suggests that the zebrafish pallium has dedicated modules for different neural processes. Pallial connections with extrapallial regions also show compartmental organization. Major extratelencephalic afferents come from preglomerular nuclei (to Dl, Dd, and Dm), posterior tuberal nucleus (to Dm), and lateral recess nucleus (to Dl). The subpallial (ventral, V) zones dorsal Vv, Vd, and Vs, considered homologues of the striatum, amygdala, and pallidum, are mainly afferent to Dl/Dd and Dp. Regarding the efferent pathways, they also appear characteristic of each pallial region. Rostral Dm projects to the dorsal entopeduncular nucleus. Dp is interconnected with the olfactory bulbs. The central region (Dc) defined here receives mainly projections from Dl–Dd and projects toward the pretectum and optic tectum, connections, which help to delimiting Dc. The connectome of the adult pallium revealed here complements extant studies on the neuroanatomical organization of the brain, and may be useful for neurogenetic studies performed during early stages of development. The connectome of the zebrafish pallium was also compared with the pallial connections reported in other teleosts, a large group showing high pallial diversity

Distribution of neurogranin-like immunoreactivity in the brain and sensory organs of the adult zebrafish

[Abstract] We studied the expression of neurogranin in the brain and some sensory organs (barbel taste buds, olfactory organs, and retina) of adult zebrafish. Database analysis shows zebrafish has two paralog neurogranin genes (nrgna and nrgnb) that translate into three peptides with a conserved IQ domain, as in mammals. Western blots of zebrafish brain extracts using an anti-neurogranin antiserum revealed three separate bands, confirming the presence of three neurogranin peptides. Immunohistochemistry shows neurogranin-like expression in the brain and sensory organs (taste buds, neuromasts and olfactory epithelium), not being able to discern its three different peptides. In the retina, the most conspicuous positive cells were bipolar neurons. In the brain, immunopositive neurons were observed in all major regions (pallium, subpallium, preoptic area, hypothalamus, diencephalon, mesencephalon and rhombencephalon, including the cerebellum), a more extended distribution than in mammals. Interestingly, dendrites, cell bodies and axon terminals of some neurons were immunopositive, thus zebrafish neurogranins may play presynaptic and postsynaptic roles. Most positive neurons were found in primary sensory centers (viscerosensory column and medial octavolateral nucleus) and integrative centers (pallium, subpallium, optic tectum and cerebellum), which have complex synaptic circuitry. However, we also observed expression in areas not related to sensory or integrative functions, such as in cerebrospinal fluid-contacting cells associated with the hypothalamic recesses, which exhibited high neurogranin-like immunoreactivity. Together, these results reveal important differences with the patterns reported in mammals, suggesting divergent evolution from the common ancestor.Xunta de Galicia; ED481A-2019/00

Expression of Urocortin 3 mRNA in the Central Nervous System of the Sea Lamprey Petromyzon marinus.

In this study, we analyzed the organization of urocortin 3 (Ucn3)-expressing neuronal populations in the brain of the adult sea lamprey by means of in situ hybridization. We also studied the brain of larval sea lampreys to establish whether this prosocial neuropeptide is expressed differentially in two widely different phases of the sea lamprey life cycle. In adult sea lampreys, Ucn3 transcript expression was observed in neurons of the striatum, prethalamus, nucleus of the medial longitudinal fascicle, torus semicircularis, isthmic reticular formation, interpeduncular nucleus, posterior rhombencephalic reticular formation and nucleus of the solitary tract. Interestingly, in larval sea lampreys, only three regions showed Ucn3 expression, namely the prethalamus, the nucleus of the medial longitudinal fascicle and the posterior rhombencephalic reticular formation. A comparison with distributions of Ucn3 in other vertebrates revealed poor conservation of Ucn3 expression during vertebrate evolution. The large qualitative differences in Ucn3 expression observed between larval and adult phases suggest that the maturation of neuroregulatory circuits in the striatum, torus semicircularis and hindbrain chemosensory systems is closely related to profound life-style changes occurring after the transformation from larval to adult life

Anatomy and Connectivity of the Torus Longitudinalis of the Adult Zebrafish

[Abstract] This study describes the cytoarchitecture of the torus longitudinalis (TL) in adult zebrafish by using light and electron microscopy, as well as its main connections as revealed by DiI tract tracing. In addition, by using high resolution confocal imaging followed by digital tracing, we describe the morphology of tectal pyramidal cells (type I cells) that are GFP positive in the transgenic line Tg(1.4dlx5a-dlx6a:GFP)ot1. The TL consists of numerous small and medium-sized neurons located in a longitudinal eminence attached to the medial optic tectum. A small proportion of these neurons are GABAergic. The neuropil shows three types of synaptic terminals and numerous dendrites. Tracing experiments revealed that the main efference of the TL is formed of parallel-like fibers that course within the marginal layer of the optic tectum. A toral projection to the thalamic nucleus rostrolateralis is also observed. Afferents to the TL come from visual and cerebellum-related nuclei in the pretectum, namely the central, intercalated and the paracommissural pretectal nuclei, as well as from the subvalvular nucleus in the isthmus. Additional afferents to the TL may come from the cerebellum but their origins could not be confirmed. The tectal afferent projection to the TL originates from cells similar to the type X cells described in other cyprinids. Tectal pyramidal neurons show round or piriform cell bodies, with spiny apical dendritic trees in the marginal layer. This anatomical study provides a basis for future functional and developmental studies focused on this cerebellum-like circuit in zebrafish.IB was supported by a Sir Henry Dale Fellowship from the Royal Society and Wellcome Trust (101195/Z/13/Z) and a UCL Excellence Fellowship. This project was also funded by University of A CoruñaReino Unido. Royal Society; 101195/Z/13/

Developmental genoarchitectonics as a key tool to interpret the mature anatomy of the chondrichthyan hypothalamus according to the prosomeric model

The hypothalamus is a key vertebrate brain region involved in survival and physiological functions. Understanding hypothalamic organization and evolution is important to deciphering many aspects of vertebrate biology. Recent comparative studies based on gene expression patterns have proposed the existence of hypothalamic histogenetic domains (paraventricular, TPa/PPa; subparaventricular, TSPa/PSPa; tuberal, Tu/RTu; perimamillary, PM/PRM; and mamillary, MM/RM), revealing conserved evolutionary trends. To shed light on the functional relevance of these histogenetic domains, this work aims to interpret the location of developed cell groups according to the prosomeric model in the hypothalamus of the catshark Scyliorhinus canicula, a representative of Chondrichthyans (the sister group of Osteichthyes, at the base of the gnathostome lineage). To this end, we review in detail the expression patterns of ScOtp, ScDlx2, and ScPitx2, as well as Pax6-immunoreactivity in embryos at stage 32, when the morphology of the adult catshark hypothalamus is already organized. We also propose homologies with mammals when possible. This study provides a comprehensive tool to better understand previous and novel data on hypothalamic development and evolutionThis work was supported by Ministerio de Economía, Industria y Competitividad – Agencia Estatal de Investigación (grant No. BFU2017-89861-P) partially financed by the European Social Fund, and by Xunta de Galicia (grant No. ED431C 2021/18)S

Regionalization of the Shark Hindbrain: A Survey of an Ancestral Organization

Cartilaginous fishes (chondrichthyans) represent an ancient radiation of vertebrates currently considered the sister group of the group of gnathostomes with a bony skeleton that gave rise to land vertebrates. This out-group position makes chondrichthyans essential in assessing the ancestral organization of the brain of jawed vertebrates. To gain knowledge about hindbrain evolution we have studied its development in a shark, the lesser spotted dogfish Scyliorhinus canicula by analyzing the expression of some developmental genes and the origin and distribution of specific neuronal populations, which may help to identify hindbrain subdivisions and boundaries and the topology of specific cell groups. We have characterized three developmental periods that will serve as a framework to compare the development of different neuronal systems and may represent a suitable tool for comparing the absolute chronology of development among vertebrates. The expression patterns of Pax6, Wnt8, and HoxA2 genes in early embryos of S. canicula showed close correspondence to what has been described in other vertebrates and helped to identify the anterior rhombomeres. Also in these early embryos, the combination of Pax6 with protein markers of migrating neuroblasts (DCX) and early differentiating neurons (general: HuC/D; neuron type specific: GAD, the GABA synthesizing enzyme) revealed the organization of S. canicula hindbrain in both transverse segmental units corresponding to visible rhombomeres and longitudinal columns. Later in development, when the interrhombomeric boundaries fade away, accurate information about S. canicula hindbrain subdivisions was achieved by comparing the expression patterns of Pax6 and GAD, serotonin (serotoninergic neurons), tyrosine hydroxylase (catecholaminergic neurons), choline acetyltransferase (cholinergic neurons), and calretinin (a calcium-binding protein). The patterns observed revealed many topological correspondences with other vertebrates and led to reconsideration of the current view of the elasmobranch hindbrain segmentation as peculiar among vertebrates

Inclusión social en alumnos en el DIIT

En un contexto regional de creciente desigualdad y exclusión social, el debate actual sobre las políticas de la educación superior en relación a la inclusión social apunta a incluir en la universidad a una diversidad (social, racial, cultural,sexual, etc.) análoga a la que existe en el seno de la sociedad, procurando remediar esas desigualdades históricas que han conducido a la reproducción de la situación de exclusión (social y educativa)por la que atraviesan diferentes grupos. El desafío en este sentido, es llevar a cabo diferentes acciones que logren la inclusión de estos grupos sin sacrificar en lo más mínimo la excelencia y la calidad académicas propias del nivel superior. Este tema adquiere especial relevancia en poblaciones marginadas socialmente, altamente vulnerables, para las cuales el ingreso a las universidades suele ser casi “impensable”.La UNLaM desarrolla acciones de Inclusión Social de los estudiantes, guiada por la normativa de la Ley de Educación Superior, las políticas universitarias nacionales y su propio Estatuto Universitario. En un Proyecto de Investigación sobre “Inclusión Social de Alumnos de la UNLaM” se destacan las siguientes acciones: Biblioteca sonora para invidentes; PC con teclado braille para invidentes; Sillas rodantes y bastones canadienses; Becas para ayuda económica, con acompañamiento de tutores; Rampas de desplazamiento en patios, aulas, pasillos y otros; Tutorías de materias; Apuntes de cátedras a bajo costo y gratuitos; Traductores en lenguaje de señas para sordos e hipoacúsicos; Becas de alimentos para el comedor universitario; Actividades de socialización a través de teatro, danzas, dibujo y pintura, canto y otros; Pasantías rentadas; Acompañamiento de alumnos extranjeros para su adaptación.Fil: Zanga, Amanda Mabel. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Donadello Anadón, Bettina Laura. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Anadón, Hebe Carlota. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Arrúe, Marcos Horacio. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Cantore, María Cristina. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Ezeiza Phol, Ana Carolina. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Goitea, Alejandro Oscar. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Kotliar, Nicolás Félix. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Nisi, Zulema Juana. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Pafundi, Federico Ramón. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Ravinale, Carolina Mabel. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina.Fil: Sánchez, Carolina Florencia. Universidad Nacional de La Matanza. Departamento de Ingeniería e Investigaciones Tecnológicas; Argentina

Red de reservas marinas para la Región de las Grandes Islas, Golfo de California: protocolo del proyecto de planeación y reporte de los talleres del equipo de planeación [Marine reserves network for the Midriff Islands Region, Gulf of California, Mexico: planning protocol and progress report to the WWF Mexico & Carlos Slim Foundation Alliance]

La Región de las Grandes Islas (RGI), localizada en el acuario del mundo, el Golfo de California, es reconocida a nivel mundial por su espectacular belleza, diversidad y productividad; en ocasiones se le ha denominada como "las Galápagos del Hemisferio Norte" (Figura 1). En sus 45 islas, incluyendo las dos más grandes de México, Tiburón e Isla Ángel de la Guarda, se han registrado más de 400 especies de plantas, anfibios, reptiles y mamíferos terrestres, algunas de ellas endémicas a una o varias de las islas. En algunas de estas islas, como Rasa y San Pedro Mártir, llegan a anidar cientos de miles de aves marinas. Alrededor de este gran archipiélago, se pueden observar hasta 23 especies de mamíferos marinos, incluyendo la súper agregación de cachalotes en la cuenca San Pedro Mártir. Así como también es un sitio usado por cinco especies de tortugas marinas para hibernar y alimentarse. [English] In collaboration with researchers, agencies and NGOs, we aim to guide the design and implementation of a network of marine reserves for Midriff Islands, Gulf of California, a marine conservation hotspot. The area is one of the most important fishing regions in Mexico and livelihoods of coastal communities are threatened by depletion of fish stocks and climate change. The project aims to develop a practical approach to design networks of marine reserves that consider ecological connectivity and the effects of climate change. The project is an example of interdisciplinary and collaborative applied research, including over 25 researchers and managers from NGOs (COBI, Pronatura), universities (James Cook University, The University of Queensland, Arizona State University, SCRIPPS, The University of Arizona), and national (Mexico’s Commissions for Protected Areas and Biodiversity) and international agencies (NOAA)

Nuevos datos sobre el Plioceno del Baix Ebre. Aportación a la correlación entre las escalas marina y continental

[ES] Con motivo del hallazgo de nuevos yacimientos de vertebrados en los depósitos pliocénicos de las cercanías de Campredó (Baix Ebre. Tarragona), se revisan los cortes clásicos de Sant Onofre y de la Vía Férrea. La sucesión del Plioceno del Baix Ebre consta aquí de dos unidades principales. La inferior, constituída por lutitas, areniscas y conglomerados, con fauna marina ha sido atribuida por otros autores al Plioceno medio-superior de la escala marina. La unidad superior, constituida por calizas y margas con intercalaciones lignitosas de origen lacustre, ha proporcionado una fauna de micromamíferos de edad Rusciniense inferior (zona MN14 de MEIN). Desde el punto de vista de la correlación entre escalas estratigráficas esta sucesión muestra que niveles lacustres de edad Rusciniense inferior (Plioceno inferior de la escala continental) se superponen a niveles de edad Plioceno medio-superior de la escala marina.[EN] The classical sections of Sant Qnofre and Vía Férrea (Baix Ebre, Tarragona) are revised on the basis of new vertebrates found in Pliocene beds near Campredó. The Pliocene of Baix Ebre has two main units. The lower unit is formed by mudstones, sandstones and conglomerates bearing marine fauna that has been dated as Middle-Upper Pliocene (marine scale). Tlie Upper unit is formed by lacustrine marls and limestones with interbedded Iignites. Micromammals of Lower Ruscinian age (zone MN14 of MEIN) have been found in this Upper unit. Thus this section points out that lacustrine beds of Lower Ruscinian age (Lower Pliocene on the continental scale) overlai beds dated as Middle to Upper Pliocene according to the marine scale.Esta nota ha sido realizada dentro del proyecto Evolución Geodinámica de las fosas neógenas del noreste de la Península Ibérica, que se enmarca dentro del programac-4-0010-8 1 (C. S. I. C. y Com. Ass. Científ. y Técnica).Peer reviewe