Endoreplication as molecular trick during animal neuron evolution.

The 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

The avian community of the karen mogensen reserve, a wealth of biodiversity within the poorly investigated and threatened environments of northwestern costa rica

Despite being characterized by some of the most threatened forest ecosystems of Mesoamerica, the Nicoya Peninsula is among the least known regions of neotropical Costa Rica in terms of its birdlife. Within this region, in the framework of an ongoing international cooperation program between Italy and Costa Rica, we had the opportunity to investigate the Karen Mogensen Reserve, a protected area distinguished by the presence of a variety of habitats, including tropical dry forest and moist forest. Species richness in the Reserve was relatively high compared with similar areas in northwestern Costa Rica. A series of surveys carried out over a 20-year period documented an avian community consisting of 207 species, of which 115 were breeding in the zone and another 14 were potentially breeding. We recorded five IUCN globally Vulnerable or Near-Threatened species, along with six species reported for the first time from the Nicoya Peninsula, each representing range extension of more than 100 km. Twenty-six species, mostly breeding in the area, are at their southernmost range borders, and are likely susceptible to global environmental alterations, such as the effects of climate change. Furthermore, our study revealed the presence of two species endemic to a restricted area of Central America and four subspecies endemic to Costa Rica, along with breeding populations of two species that are geographically isolated from the main ones. The present analysis led to the ecological characterization of the resident avian community, showing that 65% of the species are strictly associated with forested environments, and especially with the understory or middle tree level, hence more vulnerable to environmental change (climatic, anthropogenic, etc.) and susceptible to local extinction. These results underscore the importance of the Karen Mogensen Reserve for bird conservation within a vulnerable environmental context, and warrant the continuation of periodic bird surveys, taxonomic study of isolated populations or endemic taxa, and improvement of local conservation measures. The data collected will be an important tool for future studies aimed at evaluating the consequences of habitat fragmentation and to monitor the effects of climate change on the resident avifauna. We exhort the creation of programs that integrate bird monitoring, ecological research, conservation initiatives, and the involvement of the local communities, by promoting environmental education, capacity-building, and income generation. To this purpose, the Karen Mogensen Reserve may represent a convincing model and valuable example to apply in similar neotropical contexts

Microglia proliferation as a response to activation in the freshwater snail Planorbarius corneus: A BrdU incorporation study

Invertebrate microglia constitute a class of cells resident in the ganglionic nervous system which are activated after tissue injury or by the presence of pathogens. The microglia activation response includes graduated morpho-functional and biochemical changes and cell proliferation. In this study we verified in the freshwater snail Planorbarius corneus that an activation caused by a traumatic event may induce microglia division. Cell proliferation was assessed immunocytochemically using BrdU incorporation technique and documented on both ganglionic sections and microglia cultured cells at different experimental conditions and times after activation. In addition, we studied the possibility of increasing microglia proliferation by adding to the cultured medium the Macrophage-Colony Stimulating Factor (M-CSF) that has been shown to stimulate specifically this process in vertebrates

Neuron-microglia communication in the CNS of the freshwater snail Planorbarius corneus

The aim of the present study was to identify molecules that may be involved in neuron-microglia communication in the CNS of freshwater snail Planorbarius corneus. Messenger molecules are exchanged in normal and pathological conditions and we tried to identify some of them by immunocytochemistry on whole ganglia and cell cultures. In particular, we examined neurons and microglia for the expression of some cytokines, IL-1alpha, IL-1beta, IL-6 and TNF-alpha and the neurotransmitter glutamate. These substances may be released by suffering or injured neurons and communicate to microglia the damaging event. Even microglia, on own turn, once activated, express and released the same or other substances in order to re-restablish the system homeostasis, depending on modalities and times of activation. We discuss the possibility that hyperactivated microglia can shift from neuroprotective to neurodegenerative. Moreover, we examined in neuron-microglia co-coltures the direct interaction effects in terms of neuronal survival and improved neurite regeneration

OCCURRENCE AND DISTRIBUTION OF INSULIN RECEPTOR-LIKE IMMUNOREACTIVITY IN MOLLUSCAN BRAINS

Insulin receptor-like immunoreactivity (IR) was investigated in the central ganglia of different gastropod molluscs using a monoclonal antiserum raised against an epitope of the human placental insulin receptor. A well detectable and clear location of immunoreactive material was mainly found in the CNS of the freshwater snails Planorbarius corneus and Lymnaea stagnalis. This evidence correlates quite suggestively with the occurrence in these snails of a molluscan insulin peptide (MIP) previously shown. The widespread and discrete distribution of IR over a variety of physiologically distinct regions of P. corneus and L. stagnalis ganglia argues that these ''receptors'' may modulate multiple functions within the CNS

Morfologia del sistema sensoriale cutaneo di Planorbarius corneus (Mollusca, Gastropoda)

In questo studio si \ue8 proceduto a un esame estensivo dell'epidermide di Planorbarius corneus con particolare interesse alla identificazione e disribuzione delle cellule nervose recettrici. La combinazione di tecniche di impregnazione argentica, un uso originale del colorante fluorescente Lucifer Yellow e la microscopia elettronica a scansione hanno permesso di ottenere un quadro completo della morfologia di ogni zona esaminata. Le cellule recettrici, fornite di cigla e/o microvilli sulla loro terminazione distale, sono neuroni bipolari primari il cui corpo cellulare si trova direttamente nella zona subepiteliale o dislocato nei gangli centrali. Alla base dei tentacoli, sul bordo delle labbra e del piede, sulla superficie della regione buccale, sul bordo della cavit\ue0 mantellare e del pneumostoma e nell'annesso organo osfradiale sono state individuate maggiori concentrazioni di recettori

Presence and role of nitric oxide in the central nervous system of the freshwater snail Planorbarius corneus: possible implication in neuron-microglia communication

The aim of the present study was to investigate the involvement of nitric oxide (NO) as a messenger molecule in neuron-microglia communication in the central nervous system (CNS) of the freshwater snail Planorbarius corneus. The presence of both neuronal (nNOS) and inducible nitric oxide synthase (iNOS) was studied using NADPH-diaphorase (NADPH-d) histochemistry and NOS immunocytochemistry. The experiments were performed on whole ganglia and cultured microglial cells after different activation modalities, such as treatment with lipopolysaccharide and adenosine triphosphate and/or maintaining ganglia in culture medium till 7 days. In sections, nNOS immunoreactivity was found only in neurons and nNOS-positive elements were less numerous than NADPH-d-positive ones, with which they partially overlapped. The iNOS immunoreactivity was observed only after activation, in both nerve and microglial cells. We also found that the number of iNOS-immunoreactive neurons and microglia varied, depending on the activation modalities. In microglial cell cultures, iNOS was expressed in the first generation of cells only after activation, whereas a second generation, proliferated after ganglia activation, expressed iNOS even in the unstimulated condition

Light and electron microscope immunocitochemistry of a molluscan insulin-related peptide in the central nervous system of Planorbarius corneus

Two groups of cerebral dorsal cells of the pulmonate snail Planorbarius corneus stain positively with antisera raised against synthetic fragments of the B- and C-chain of the molluscan pro-insulin-related pro-hormone, proMIP-I, of another pulmonate snail, Lymnaea stagnalis. At the light-microscopic level the somata of the dorsal cells and their axons and neurohemal axon terminals in the periphery of the paired median lip nerves are immunoreactive with both antisera. Furthermore, the canopy cells in the lateral lobes of the cerebral ganglia are positive. In addition, MIP(B)-immunoreactive neurons are found in most other ganglia of the central nervous system. At the ultrastructural level, pale and dark secretory granules are found in somata and axon terminals of the dorsal cells. Dark granules are about 4 times as immunoreactive to both antisera as pale granules. Release of anti-MIP(B)- and anti-MIP(C)-immunopositive contents of the secretory granules by exocytosis is apparent in material treated according to the tannic acid method. It is concluded that the dorsal and canopy cells synthesize a molluscan insulin-related peptide that is packed in the cell body into secretory granules and that is subsequently transported to the neurohemal axon terminals and released into the hemolymph by exocytosis. Thus, MIP seems to act as a neurohormone on peripheral targets. On the basis of the analogy between the dorsal cells and the MIP-producing cells in L. stagnalis, it is proposed that the dorsal cells of P. corneus are involved in the control of body growth and associated processes

Trauma increases endogenous morphine levels in nervous and immune tissues of the feshwater snail Planorbarius corneus.

Sono descritti gli effetti di un trattamento traumatico sui livelli di morfina endogena in cellule sia del sistema immunitario che di quello nervoso nel gasteropode Planorbariu

Mostra "Biodiversità: dalla camera delle meraviglie alla salvaguardia del pianeta verde" (Modena, Foro Boario, 19 giugno - 6 luglio 2008), in occasione dei 250 anni dell’Orto Botanico di Modena

La mostra, attraverso esposizioni politematiche, evidenzia aspetti diversi della biodiversità, dalle origini delle sue conoscenze, ai problemi legati alla perdita di specie, alla distruzione degli habitat e degli ecosistemi, fino agli attuali temi della conservazione in situ/ex situ. L'esposizione prende avvio da una prima sezione dedicata alla ricostruzione di una camera delle meraviglie (a cura di E. Corradini), per rappresentare le origini di un collezionismo eclettico nel quale del mondo naturale venivano evidenziati gli aspetti più curiosi e singolari. Prosegue con due sezioni che illustrano i temi della diversità biologica, delle minacce a cui è esposta e della conservazione delle risorse per le generazioni presenti e future: nella seconda sezione (a cura di D.Sonetti) sono evidenziati i rischi di estinzione delle specie vegetali e animali derivanti dalle azioni dell'uomo esercitate sull'ambiente, nella terza sezione (a cura di D.Dallai) sono illustrate le attività degli Orti Botanici per la conservazione del patrimonio fitogenetico con approfondimenti sulla storia, le attività e le collezioni dell'Orto Botanico Universitario di Modena. Con il patrocinio di: Società Botanica Italiana e Instituto Nacional de Biodiversidad de Costarica.Contributi espositivi: Società Botanica Italiana - Gruppo di Lavoro per gli Orti Botanici e i Giardini Storici; Consorzio di Bonifica Burana, Leo, Scoltenna e Panaro; Guardie Ecologiche Volontarie della Provincia di Modena. Contributi scientifici: Società Botanica Italiana, C.A. Accorsi, C.Del Prete, M.Mazzanti, A, Pederzoli, R.Guidetti, E.Sgarbi, M.Grimaudo, P.Torri, L.Maffettone, G.Bosi, S.Rossi, G.Barbieri.La sezione "Biodiversità, il suo valore tra il perderla e conservarla" (a cura di D.Sonetti) è parte della Mostra "Uomo, Foreste e Clima" di GEV MOdena - FpS., progetto espositivo e testi del Dott. A.Portanova e L.Daddario. Contributi fotografici di E.Turrillazzi, F.Liverani, N.Tignosini.Contributi organizzativi: S.Rossi, B.Viaro, F.Rozzi, A.Morini, L.Bettelli, M.Casartelli, D.Bertoni, GEV Modena - Foreste per Sempre. Assistenza all'allestimento: S.Fregni, S.Rinaldi, E.Villani, R.ShehuSi ringraziano per la collaborazione la Prof. A.Pederzoli e il Dott. R. Guidetti dell'Università di Modena e Reggio Emilia, il Dott. Luca Bellingeri, Direttore e la Dott. Paola di Pietro e i colleghi della Biblioteca Estense