1,720,966 research outputs found
The supramedullary neurons of fish: present status and goals for the future
No full textIn this paper, we report the recent findings on supramedullary neurons of fish, with special attention to the studies, which made the nature of this neuronal system clear. Indeed, immunohistochemical, physiological and neuroanatomical data, taken together, point out that this neuronal system is a component of the autonomic nervous system. New goals have been opened by the more recent research, expecially in comparative neurobiology. Indeed, the supramedullary neurons, owing to some characteristics, like the DNA endoreplication, the large size, the accessible localization and the relationship with glial cells, may be utilised as a very suitable model in several fields of neurobiology of vertebrates, such as molecular genetic, electrophysiology, nervous system ageing, glial-neuron interactions
Principi di Endocrinologia comparata
No full textConsiderata l’importanza che il sistema endocrino ha assunto di recente in campo scientifico, quest’opera vuole colmare una lacuna nel panorama editoriale dei testi in lingua italiana per studenti di Biologia. Vengono trattati argomenti di Endocrinologia Comparata classica da un punto di vista morfo-funzionale ed evolutivo. Il tutto è stato inqua-drato nell’ottica, ormai definitivamente accettata, secondo la quale il sistema endocrino collabora strettamente con quello nervoso e quello immunitario, mettendo in atto reazioni di adattamento in risposta a stimoli provenienti sia dall’ambiente esterno che da quello interno, per mantenere l’omeostasi dell’organismo. Così, accanto a paragrafi che riguardano l’evoluzione della struttura di alcune ghiandole o della fun-zione di determinati ormoni, trovano posto il capitolo iniziale sull’evoluzione delle molecole di comunicazione e numerosi spunti sull’utilizzo, da parte dei tre sistemi, delle stesse molecole e sui diversi livelli dell’integrazione immuno-neuroendocrina
Citometria dei neuroni sopramidollari: il caso di Solea ocellata
No full textNel midollo spinale di Solea ocellata è stata rilevata la presenza di circa 70 neuroni sopramidollari, distribuiti a gruppetti di 2-3-4, nella prima metà del midollo. La forma dei neuroni è variabile, mentre il nucleo è generalmente rotondeggiante o subellittico.Sono presenti numerosi vacuoli citoèplasmatici e capillari endocellulari. I dati citometrici hanno messo in evidenza un'estrema variabilità e un ampio range dimensionale di cellule e nuclei. la determinazione citofluorimetrica su preparati trattati con bromuro d'etidio ha rivelato un contenuto di DNA da 6C a 100C. nel complesso questi risultati indicano che i neuroni sopramidolalri di S. ocellata hanno caratteristiche intermedie tra quelli "allineati" e quelli "clusterizzati"
CYTOMETRY OF SUPRAMEDULLARY NEURONS IN SOLEA OCELLATA
No full textThe supramedullary neurons (SN) are a noradrenergic autonomic system of giant cells, dorsally grouped in a cluster at the boundary between medulla oblongata and spinal cord in some orders of fish, and aligned one by one along the spinal cord in others. Morphology, number and size are peculiar for each species. The axons of SN terminate in the epidermal layer near the mucous glands. Because of the role of aspecific defence of skin mucous cells in fish, the SN system may act in protection from predaction or prevent infection. In this view the study of SNS is very interesting in species fishing of considerable market price.The SN of Solea ocellata, about 70, are distributed in small groups of 2-4 along the cord. The unique nucleolus is intensely basophilic. Vacuoles and endocellular capillaries are present in the cytoplasm, as in SN clustered. The cytometry showed a large variability and a wide range of cells and nuclei size. On the contrary, the nucleoli showed an almost uniform size. The nuclei showed an intense Feulgen-positivity. The cytofluorimetric evaluation revealed a DNA content ranging from 6C in the smaller neurons to 100C in the larger ones, indicating that the peculiar phenomenon of DNA amplification is present also in the SN of S. ocellata, as so far known in those clustered only. Thus, the SN of S. ocellata have characteristics between those clustered and those aligned. The case of S. ocellata suggests that the parting of SN in “aligned” and “clustered” should not be interpreted in absolute way, because this neuronal system shows in different species a wide morphological variability, which reflects functional differences, probably related to environment and behaviour
Macroglial cells of the teleost central nervous system: A survey of the main types
No full textFollowing our previous review of teleost microglia,we focus here on the morphological and histochemicalfeatures of the three principal macroglia types in the teleostcentral nervous system (ependymal cells, astrocyte-likecells/radial glia and oligodendrocytes). This review isconcerned with recent literature and not only providesinsights into the various individual aspects of the differenttypes of macroglial cells plus a comparison with mammalianglia, but also indicates the several potentials that theneural tissue of teleosts exhibits in neurobiological research.Indeed, some areas of the teleost brain areparticularly suitable in terms of the establishment of a“simple” but complete research model (i.e. the visualpathway complex and the supramedullary neuron clusterin puffer fish). The relationships between neurons and glialcells are considered in fish, with the aim of providing anintegrated picture of the complex ways in which neuronsand glia communicate and collaborate in normal andinjured neural tissues. The recent setting up of successfulprotocols for fish glia and mixed neuron-glia cultures,together with the molecular facilities offered by theknowledge of some teleost genomes, should allow consistentinput towards the achievement of this aim
Endoreplication as molecular trick during animal neuron evolution.
No full textThe occurrence of endoreplication has been repeatedly reported in many organisms, including protists, plants, worms, arthropods, molluscs, fishes, and mammals. As a general rule, cells possessing endoreplicated genomes are large-sized and highly metabolically active. Endoreplication has been not frequently reported in neuronal cells that are typically considered to be fully differentiated and non-dividing, and which normally contain a diploid genome. Despite this general statement, various papers indicate that giant neurons in molluscs, as well as supramedullary and hypothalamic magnocellular neurons in fishes, contain DNA amounts larger than 2C. In order to study this issue in greater detail here, we review the available data about endoreplication in invertebrate and vertebrate neurons, and discuss its possible functional significance. As a whole, endoreplication seems to be a sort of molecular trick used by neurons in response to the high functional demands that they experience during evolution
Neuronal nitric oxide synthase in the supramedullary cells of the puffer fish Tetraodon fluviatilis
No full textAn anti-Bcl-2 antibody prevents 2-deoxy-D-ribose-induced apoptosis in the IPLB-LdFB insect cell line
No full textConfocal microscopy reveals that the anti-Bcl-2 antibody (pAb) is able to diffuse across the plasma membrane of the fat body cell line IPLB-LdFB from the insect Lymantria dispar demonstrating the presence of Bcl-2-like molecules in the cytoplasm. Immunoperoxidase procedure confirms the cellular localization. Furthermore, an immunoprecipitation corresponding to a molecular weight of 29 KDa is observed with western blot analysis using the anti-Bcl-2 pAb. Cytofluorimetric experiments show that anti-Bcl-2 pAb counteracts 2-deoxy-D-ribose-induced apoptosis and provokes morphological changes in the insect cell line, i.e. a reduction in cell size, the disappearance of the vacuola and changes in shape. At the same time, the antibody provokes mitochondrial membrane depolarization, and N-acetyl-L-cysteine is unable to reconstitute the physiological conditions. The present findings suggest that Bcl-2-like proteins play a main role in maintaining of the integrity of cellular components, e.g, mitochondria, rather than in controlling programmed cell death
Use of cytometry for the "reproductive model" assessment of the shrimp Palaemon serratus (Pennant, 1777).
No full textThe reproductive biology of the shrimp Palaemon serratus (Crustacea, Decapoda), fisheries resources, has been scarcely studied, especially in the marine habitats of Italian waters. For this purpose, in the present study, monthly samples were taken in brackish waters of the Po River Delta in the North Adriatic Sea. The annual maturative cycle of the ovary was assessed both qualitative, on the basis of histological findings, and quantitative terms, by cytometry. The ovaries feature a proliferative centre from which maturing oocytes branch out in a centrifugal direction. The reproductive period falls between March and June. During the non-reproductive period oocyte diameter ranged from 24 to 153 m, whilst during the reproductive period ranged from 24 to 733 m. The oviposition pattern may be described as “fractioned”, since it is recurrent. In fact, histological and cytometric findings of the Spring catch revealed that the females had both issued eggs that were still attached to the abdomen, as well as oocytes in all stages of vitellogenesis. The size at first maturity was around 51 mm of length.In conclusion, the histo-cytological approach applied throughout the ovary maturation cycle is a good “reproductive model” assessment and an environmental test because the gonadal maturation is closely dependent on enviromental conditions
Interactions supramedullary neurons-glial cells in Tetraodon fluviatilis (Osteichthyes) in vivo and in vitro.
No full textThe cluster of supramedullary neurons and glial cells of the teleost Tetraodon fluviatilis is presented as an excellent model for the study of the interactions neurons-glia. Furthermore, the cluster is well defined, easy to locate and to single out. Explants from the cluster of about 0.2-0.5 mm3 (from 6 to 12 neurons each) were cultured for 24 and 48 h. The preliminary findings, such as the good preservation of the cultured cells and the maintenance of the relations between neurons and glia in culture, are encouraging in order to go deep in such an interesting model
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