The genus Panphalea (Compositae: Nassauvieae) in Uruguay

Se realiza la revisión taxonómica de Panphalea Lag. (Compositae: Nassauvieae) para Uruguay. Panphalea en Uruguay consiste de cinco especies: Panphalea bupleurifolia Less., Panphalea cardaminifolia Less., Panphalea commersonii Cass., Panphalea heterophylla Less. y Panphalea maxima Less. Todas las especies uruguayas fueron evaluadas y circunscriptas en base al análisis de los protólogos, análisis de laboratorio, estudio cuidadoso del material tipo, observación de especímenes de herbario y observaciones a campo. Se presenta una clave dicotómica para la identificación de las especies reconocidas para el Uruguay. Para cada especie se provee sinonimia, descripciones ampliadas, distribución geográfica y dibujos. Se designan dos neotipos.A taxonomic revision of Panphalea Lag. (Compositae: Nassauvieae) for Uruguay is presented. Panphalea, in Uruguay, is composed of five species: Panphalea bupleurifolia Less., Panphalea cardaminifolia Less., Panphalea commersonii Cass., Panphalea heterophylla Less., and Panphalea maxima Less. All uruguayan species of Panphalea were taxonomically evaluated and circumscribed based on analyses of the protologues, laboratory studies, and careful study of type material, herbarium specimens and field observations. A dichotomous key for the identification of the Uruguayan species is provided. For each species, synonymy, detailed description, geographic distribution, and line drawings are presented. Two neotypes are designated.Fil: Trujillo, Cristina. Universidad de la República; UruguayFil: Katinas, Liliana. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bonifacino, José M.. Universidad de la República; Urugua

Novedades del género Tillandsia (Bromeliaceae, Tillandsioideae) para Uruguay

Se citan por primera vez para la flora de Uruguay a Tillandsia capillaris Ruiz & Pav. (= T.capillaris f. hieronymi (Mez) L.B. Sm.) y T. loliacea Mart. ex Schult. f. Tillandsia capillaris es registrada como una especie introducida y espontánea para la ciudad de Montevideo, mientras que T. loliacea es citada como especie nativa del noroeste del país. Se presenta el primer registro de T. tricholepis Baker para ambientes naturales de Uruguay, confirmando el estatus de especie nativa. Se reporta el hallazgo reciente de T. xiphioides Ker Gawl luego de 73 años sin ser colectada en Uruguay. Este trabajo provee una descripción morfológica para cada especie, incluyendo información sobre su hábitat, distribución geográfica, fenología, estatus de conservación e imágenes.Novelties in the genus Tillandsia (Bromeliaceae, Tillandsioideae) for Uruguay. Tillandsia capillaris Ruiz & Pav. (= T. capillarisf. hieronymi (Mez) L.B. Sm.) and T. loliacea Mart. ex Schult. are reported for the first time for the flora of Uruguay. Tillandsia capillaris is registered as an introduced and spontaneous species for Montevideo city, while T. loliacea is cited as native for northwestern Uruguay. Tillandsia tricholepis Baker is reported for the first time for natural environments in Uruguay, establishing its status as native. The recent finding of Tillandsia xiphioides Ker Gawl in Uruguay is reported after 73 years without being collected. We provide morphological descriptions, distribution and habitat data, phenology, conservation assessment, and images for each species treated.Fil: Rossado, Andrés J.. Universidad de la República; UruguayFil: Donadío, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Berazategui, Pablo. Asociación Civil COENDU; UruguayFil: Bonifacino, José M.. Universidad de la República; Urugua

Abnormal Upregulation of GPR17 Receptor Contributes to Oligodendrocyte Dysfunction in SOD1 G93A Mice

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive loss of motor neurons (MN). Importantly, MN degeneration is intimately linked to oligodendrocyte dysfunction and impaired capacity of oligodendrocyte precursor cells (OPCs) to regenerate the myelin sheath enwrapping and protecting neuronal axons. Thus, improving OPC reparative abilities represents an innovative approach to counteract MN loss. A pivotal regulator of OPC maturation is the P2Y-like G protein-coupled receptor 17 (GPR17), whose role in ALS has never been investigated. In other models of neurodegeneration, an abnormal increase of GPR17 has been invariably associated to myelin defects and its pharmacological manipulation succeeded in restoring endogenous remyelination. Here, we analyzed GPR17 alterations in the SOD1G93A ALS mouse model and assessed in vitro whether this receptor could be targeted to correct oligodendrocyte alterations. Western-blot and immunohistochemical analyses showed that GPR17 protein levels are significantly increased in spinal cord of ALS mice at pre-symptomatic stage; this alteration is exacerbated at late symptomatic phases. Concomitantly, mature oligodendrocytes degenerate and are not successfully replaced. Moreover, OPCs isolated from spinal cord of SOD1G93A mice display defective differentiation compared to control cells, which is rescued by treatment with the GPR17 antagonist montelukast. These data open novel therapeutic perspectives for ALS management

A multistationary loop model of ALS unveils critical molecular interactions involving mitochondria and glucose metabolism

Amyotrophic lateral sclerosis (ALS) is a poor-prognosis disease with puzzling pathogenesis and inconclusive treatments. We develop a mathematical model of ALS based on a system of interactive feedback loops, focusing on the mutant SOD1G93A mouse. Misfolded mutant SOD1 aggregates in motor neuron (MN) mitochondria and triggers a first loop characterized by oxidative phosphorylation impairment, AMP kinase over-activation, 6-phosphofructo-2-kinase (PFK3) rise, glucose metabolism shift from pentose phosphate pathway (PPP) to glycolysis, cell redox unbalance, and further worsening of mitochondrial dysfunction. Oxidative stress then triggers a second loop, involving the excitotoxic glutamatergic cascade, with cytosolic Ca2+ overload, increase of PFK3 expression, and further metabolic shift from PPP to glycolysis. Finally, cytosolic Ca2+ rise is also detrimental to mitochondria and oxidative phosphorylation, thus closing a third loop. These three loops are overlapped and positive (including an even number of inhibitory steps), hence they form a candidate multistationary (bistable) system. To describe the system dynamics, we model the interactions among the functional agents with differential equations. The system turns out to admit two stable equilibria: the healthy state, with high oxidative phosphorylation and preferential PPP, and the pathological state, with AMP kinase activation, PFK3 over expression, oxidative stress, excitotoxicity and MN degeneration. We demonstrate that the loop system is monotone: all functional agents consistently act toward the healthy or pathological condition, depending on low or high mutant SOD1 input. We also highlight that molecular interactions involving PFK3 are crucial, as their deletion disrupts the system\u2019s bistability leading to a single healthy equilibrium point. Hence, our mathematical model unveils that promising ALS management strategies should be targeted to mechanisms that keep low PFK3 expression and activity within MNs

Human Vam6p promotes lysosome clustering and fusion in vivo

Regulated fusion of mammalian lysosomes is critical to their ability to acquire both internalized and biosynthetic materials. Here, we report the identification of a novel human protein, hVam6p, that promotes lysosome clustering and fusion in vivo. Although hVam6p exhibits homology to the Saccharomyces cerevisiae vacuolar protein sorting gene product Vam6p/Vps39p, the presence of a citron homology (CNH) domain at the NH2 terminus is unique to the human protein. Overexpression of hVam6p results in massive clustering and fusion of lysosomes and late endosomes into large (2–3 μm) juxtanuclear structures. This effect is reminiscent of that caused by expression of a constitutively activated Rab7. However, hVam6p exerts its effect even in the presence of a dominant-negative Rab7, suggesting that it functions either downstream of, or in parallel to, Rab7. Data from gradient fractionation, two-hybrid, and coimmunoprecipitation analyses suggest that hVam6p is a homooligomer, and that its self-assembly is mediated by a clathrin heavy chain repeat domain in the middle of the protein. Both the CNH and clathrin heavy chain repeat domains are required for induction of lysosome clustering and fusion. This study implicates hVam6p as a mammalian tethering/docking factor characterized with intrinsic ability to promote lysosome fusion in vivo