Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto

About: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto is a based out in . It is known for research contribution in the topics: Population & Genus. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

Active Dendrites Enhance Neuronal Dynamic Range

Abstract: Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the past decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of an active dendritic tree is a highly non-linear function of its afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease in dynamic range.

Therapeutic Administration of KM+ Lectin Protects Mice Against Paracoccidioides brasiliensis Infection via Interleukin-12 Production in a Toll-Like Receptor 2-Dependent Mechanism

Abstract: KM+ is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper 1 immune response against Leishmania major infection. In this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM+ (jfKM+) and its recombinant counterpart (rKM+) in experimental paracoccidioidomycosis. To this end, jfKM+ or rKM+ was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM+-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM+-treated mice presented higher levels of nitric oxide, IL-12, interferon-γ, and tumor necrosis factor-α, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM+ led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM+ on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule.

Systematics and bionomics of the apoid obligate necrophages: the Trigona hypogea group (Hymenoptera: Apidae; Meliponinae)

Abstract: A systematic revision and biological account is given of the only apoid obligate necrophages, the Trigona hypogea group, along with descriptions of Trigona necrophaga sp. nov. and the male of Trigona crassipes. Trigona necrophaga is endemic to eastern Panama and possibly the Choco; T. hypogea and T. crassipes are sympatric throughout the Amazon Basin and the Guianas. The lack of a corbicula on the hind leg and reduction of giant setae on the labial palpi, workers foraging upon carrion, lack of stored pollen in nests, and complete absence of pollen grains in larval provisions demonstrate obligate necrophagy in all three social, stingless bee species. Evolution of T. hypogea and T. crassipes from a common ancestor in the Amazon Basin is postulated, and T. necrophaga is likely to be an offshoot of T. crassipes. Morphology links T. crassipes and T. hypogea, but nest architecture joins necrophaga and crassipes. Facultative necrophagy in Trigona probably became obligate due to preadaptations including (1) massive forager recruitment via pheromone trails; (2) aggressive foraging on carrion exudates; (3) apical mandibular teeth; (4) rapid location of novel resources; (5) beneficial microbes in bee glandular secretions that metabolize protein and produce antibiotics, and (6) queen cells and food storage pots of the same size and close proximity. Accidental placement of regurgitated, partly-digested carrion in queen cells may have promoted admixture of hypopharyngeal glandular secretions and microbes with harvested liquid carrion. The most derived species, T. necrophaga, may have additional mutualist microbes because only this species has distinctive grey-green protein, and five Bacillus species in food pots and brood cells. No unusual anatomical features were found in worker bees. All three species make sweet, clear honey that contains some pollen but is of unknown origin.