Catálogo de los peces de la cuenca Iténez (Bolivia y Brasil)

Se presenta una lista de los peces de la cuenca Iténez elaborada en base a descripciones taxonómicas originales, registros bibliográficos y estudios recientes de investigadores de Brasil y Bolivia. Las especies fueron seleccionadas considerando cinco criterios de acuerdo con la confiabilidad de la fuente de referencia. Las citas de los taxones fueron acompañadas por observaciones vinculadas a su nomenclatura, distribución geográfica conocida y su registro para la cuenca Iténez. En total, 619 taxones de peces están citadas en la literatura. De estas, 556 especies fueron reconocidas como válidas y 63 tienen identificación incompleta o representan identificaciones dudosas debido a la incompatibilidad entre su área de distribución conocida y su presencia en la cuenca del río Iténez.E apresentada urna lista de espécies de peixes da bacia Iténez*, elaborada com base em descrigóes originais para a mesma, registros bibliográficos e estudos recentes realizados por pesquisadores do Brasil e Bolívia. As espécies foram selecionadas considerando cinco critérios relacionados à veracidade de sua fonte de referencia. As citagóes dos táxons foram acompanhadas por observagóes vinculadas á nomenclatura, à distribuigao conhecida do táxon e ao seu registro na bacia Iténez. Um total de 619 espécies de peixes foram registradas. Destas, 556 espécies foram identificadas como válidas e 63 táxons foram indicados com identificagao incerta ou foram consideradas duvidosas devido às divergencias entre a distribuigao geográfica conhecida para os taxons na literatura recente e seu registro na bacia Iténez.* Iténez e denominado rio Guaporé no Brasil.A check list of the fish species of the Iténez* river basin was compiled on the basis of original species descriptions, main references and recent studies by Bolivian and Brazilian researchers. The species list was based on five criteria ordered according to the reliability of the reference. The citations of taxa were followed by notes on the nomenclature or the divergences between the generally accepted distribution of each taxon and its ocurrence in the Iténez river basin. In total, 619 fish species were recorded in the literature. Of these, 556 species were categorized as valid. Sixty three citations were considered doubtful due to uncertain identification or incompatibility between their original known geographical distribution range and their records in the Iténez river basin.* The Iténez river is known as Guaporé river in Brasil

Pparγ2 Is a Key Driver of Longevity in the Mouse

Aging involves a progressive physiological remodeling that is controlled by both genetic and environmental factors. Many of these factors impact also on white adipose tissue (WAT), which has been shown to be a determinant of lifespan. Interrogating a transcriptional network for predicted causal regulatory interactions in a collection of mouse WAT from F2 crosses with a seed set of 60 known longevity genes, we identified a novel transcriptional subnetwork of 742 genes which represent thus-far-unknown longevity genes. Within this subnetwork, one gene was Pparg (Nr1c3), an adipose-enriched nuclear receptor previously not associated with longevity. In silico, both the PPAR signaling pathway and the transcriptional signature of Pparγ agonist rosiglitazone overlapped with the longevity subnetwork, while in vivo, lowered expression of Pparg reduced lifespan in both the lipodystrophic Pparg1/2-hypomorphic and the Pparg2-deficient mice. These results establish Pparγ2 as one of the determinants of longevity and suggest that lifespan may be rather determined by a purposeful genetic program than a random process

Inside the guts of wood-eating catfishes: can they digest wood?

To better understand the structure and function of the gastrointestinal (GI) tracts of wood-eating catfishes, the gross morphology, length, and microvilli surface area (MVSA) of the intestines of wild-caught Panaque nocturnus, P. cf. nigrolineatus “Marañon”, and Hypostomus pyrineusi were measured, and contrasted against these same metrics of a closely related detritivore, Pterygoplichthys disjunctivus. All four species had anatomically unspecialized intestines with no kinks, valves, or ceca of any kind. The wood-eating catfishes had body size-corrected intestinal lengths that were 35% shorter than the detritivore. The MVSA of all four species decreased distally in the intestine, indicating that nutrient absorption preferentially takes place in the proximal and mid-intestine, consistent with digestive enzyme activity and luminal carbohydrate profiles for these same species. Wild-caught Pt. disjunctivus, and P. nigrolineatus obtained via the aquarium trade, poorly digested wood cellulose (<33% digestibility) in laboratory feeding trials, lost weight when consuming wood, and passed stained wood through their digestive tracts in less than 4 h. Furthermore, no selective retention of small particles was observed in either species in any region of the gut. Collectively, these results corroborate digestive enzyme activity profiles and gastrointestinal fermentation levels in the fishes’ GI tracts, suggesting that the wood-eating catfishes are not true xylivores such as beavers and termites, but rather, are detritivores like so many other fishes from the family Loricariidae

Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species

The Neotropical catfish genus Tympanopleura, previously synonymized within Ageneiosus, is revalidated and included species are reviewed. Six species are recognized, two of which are described as new. Tympanopleura is distinguished from Ageneiosus by having an enlarged gas bladder not strongly encapsulated in bone; a prominent pseudotympanum consisting of an area on the side of the body devoid of epaxial musculature where the gas bladder contacts the internal coelomic wall; short, blunt head without greatly elongated jaws; and smaller adult body size. Species of Tympanopleura are distinguished from each other on the basis of unique meristic, morphometric, and pigmentation differences. Ageneiosus melanopogon and Tympanopleura nigricollis are junior synonyms of Tympanopleura atronasus. Tympanopleura alta is a junior synonym of Tympanopleura brevis. A lectotype is designated for T. brevis. Ageneiosus madeirensis is a junior synonym of Tympanopleura rondoni. Tympanopleura atronasus, T. brevis, T. longipinna, and T. rondoni are relatively widespread in the middle and upper Amazon River basin. Tympanopleura cryptica is described from relatively few specimens collected in the upper portion of the Amazon River basin in Peru and the middle portion of that basin in Brazil. Tympanopleura piperata is distributed in the upper and middle Amazon River basin, as well as in the Essequibo River drainage of Guyana