Fear is the mother of invention : Anuran embryos exposed to predator cues alter life-history traits, post-hatching behaviour and neuronal activity patterns

Neurophysiological modifications associated to phenotypic plasticity in response to predators are largely unexplored, and there is a gap of knowledge on how the information encoded in predator cues is processed by prey sensory systems. To explore these issues, we exposed Rana dalmatina embryos to dragonfly chemical cues (kairomones) up to hatching. At different times after hatching (up to 40 days), we recorded morphology and anti-predator behaviour of tadpoles from control and kairomone-Treated embryo groups as well as their neural olfactory responses, by recording the activity of their mitral neurons before and after exposure to a kairomone solution. Treated embryos hatched later and hatchlings were smaller than control siblings. In addition, the tadpoles from the treated group showed a stronger anti-predator response than controls at 10 days (but not at 30 days) post-hatching, though the intensity of the contextual response to the kairomone stimulus did not differ between the two groups. Baseline neuronal activity at 30 days post-hatching, as assessed by the frequency of spontaneous excitatory postsynaptic events and by the firing rate of mitral cells, was higher among tadpoles from the treated versus the control embryo groups. At the same time, neuronal activity showed a stronger increase among tadpoles from the treated versus the control group after a local kairomone perfusion. Hence, a different contextual plasticity between treatments at the neuronal level was not mirrored by the anti-predator behavioural response. In conclusion, our experiments demonstrate ontogenetic plasticity in tadpole neuronal activity after embryonic exposure to predator cues, corroborating the evidence that early-life experience contributes to shaping the phenotype at later life stages

Seleção de linhagens de leveduras multicompetentes em produção de ácido indolacético e biossolubilização de fósforo.

O uso de fertilizantes químicos na agricultura brasileira se intensificou com a expansão da fronteira agrícola. Porém, a utilização desses insumos em culturas agrícolas gera danos ambientais. Assim, a substituição deles por biofertilizantes se torna essencial para um futuro sustentável. Este trabalho possui como objetivo a caracterização e a seleção de linhagens selvagens de leveduras multicompetentes para a produção de ácido indolacético (IAA) e para a biossolubilização de fósforo (P) em meios com Ca3(PO4)2, FePO4 e AlPO4, a fim de buscar linhagens com potencial para biofertilização. Para a determinação da solubilização de P, setenta e duas linhagens de leveduras de diferentes espécies foram inoculadas em meio sólido NBRIP contendo Ca3(PO4)2, FePO4 ou AlPO4. A avaliação foi realizada por meio do índice de solubilização (IS), calculado por meio da razão da média das medidas de halos formados por solubilização do meio pela média do diâmetro das quatro colônias, por placa. Para a quantificação de IAA, as leveduras foram inoculadas em meio líquido de YPD com L‑triptofano (L‑Trp) 0,1% e amostras foram retiradas após 120 horas para quantificação do fitormônio por método colorimétrico. Por fim, doze linhagens que demonstraram produção de IAA entre 13 μg/mL e 65 μg/mL foram selecionadas e avaliadas quanto à solubilização de P em meio líquido NBRIP com as fontes fosfóricas Ca3(PO4)2, FePO4 e AlPO4. Os resultados revelaram que as leveduras estudadas somente apresentam capacidade de formação de halos de solubilização em meio sólido com Ca3(PO4)2. No entanto, houve solubilização de P em meio líquido com todas as fontes fosfóricas. Quanto à multicompetência, os dados apontam que, dentre as 72 linhagens avaliadas de 29 espécies diferentes, destacaram‑se três linhagens de diferentes espécies. Desse modo, tais linhagens são candidatas promissoras para a biofertilização de culturas comerciais

Dietary Supplementation of Hericium erinaceus Increases Mossy Fiber-CA3 Hippocampal Neurotransmission and Recognition Memory in Wild-Type Mice

Hericium erinaceus (Bull.) Pers. is a medicinal mushroom capable of inducing a large number of modulatory effects on human physiology ranging from the strengthening of the immune system to the improvement of cognitive functions. In mice, dietary supplementation with H. erinaceus prevents the impairment of spatial short-term and visual recognition memory in an Alzheimer model. Intriguingly other neurobiological effects have recently been reported like the effect on neurite outgrowth and differentiation in PC12 cells. Until now no investigations have been conducted to assess the impact of this dietary supplementation on brain function in healthy subjects. Therefore, we have faced the problem by considering the effect on cognitive skills and on hippocampal neurotransmission in wild-type mice. In wild-type mice the oral supplementation with H. erinaceus induces, in behaviour test, a significant improvement in the recognition memory and, in hippocampal slices, an increase in spontaneous and evoked excitatory synaptic current in mossy fiber-CA3 synapse. In conclusion, we have produced a series of findings in support of the concept that H. erinaceus induces a boost effect onto neuronal functions also in nonpathological conditions

Nanoparticulate TiO2-promoted PtRu/C catalyst for methanol oxidation: TiO2 nanoparticles promoted PtRu/C catalyst for MOR

To improve the electrocatalytic properties of PtRu/C in methanol electrooxidation, nanoparticulate TiO2-promoted PtRu/C catalysts were prepared by directly mixing TiO2 nanoparticles with PtRu/C. Using cyclic voltammetry, it was found that the addition of 10 wt% TiO2 nanoparticles can effectively improve the electrocatalytic activity and stability of the catalyst during methanol electro-oxidation. The value of the apparent activation energy (Ea) for TiO2-PtRu/C was lower than that for pure PtRu/C at a potential range from 0.45 to 0.60 V. A synergistic effect between PtRu and TiO2 nanoparticles is likely to facilitate the removal of CO-like intermediates from the surface of PtRu catalyst and reduce the poisoning of the PtRu catalysts during methanol electrooxidation. Therefore, we conclude that the direct introduction of TiO2 nanoparticles into PtRu/ C catalysts offers an improved facile method to enhance the electrocatalytic performance of PtRu/C catalyst in methanol electrooxidation.Web of Scienc