Myelination induces axonal hotspots of synaptic vesicle fusion that promote sheath growth

Myelination of axons by oligodendrocytes enables fast saltatory conduction. Oligodendrocytes are responsive to neuronal activity, which has been shown to induce changes to myelin sheaths, potentially to optimize conduction and neural circuit function. However, the cellular bases of activity-regulated myelination in vivo are unclear, partly due to the difficulty of analyzing individual myelinated axons over time. Activity-regulated myelination occurs in specific neuronal subtypes and can be mediated by synaptic vesicle fusion, but several questions remain: it is unclear whether vesicular fusion occurs stochastically along axons or in discrete hotspots during myelination and whether vesicular fusion regulates myelin targeting, formation, and/or growth. It is also unclear why some neurons, but not others, exhibit activity-regulated myelination. Here, we imaged synaptic vesicle fusion in individual neurons in living zebrafish and documented robust vesicular fusion along axons during myelination. Surprisingly, we found that axonal vesicular fusion increased upon and required myelination. We found that axonal vesicular fusion was enriched in hotspots, namely the heminodal non-myelinated domains into which sheaths grew. Blocking vesicular fusion reduced the stable formation and growth of myelin sheaths, and chemogenetically stimulating neuronal activity promoted sheath growth. Finally, we observed high levels of axonal vesicular fusion only in neuronal subtypes that exhibit activity-regulated myelination. Our results identify a novel "feedforward" mechanism whereby the process of myelination promotes the neuronal activity-regulated signal, vesicular fusion that, in turn, consolidates sheath growth along specific axons selected for myelination

Pulmonary cryptococcosis induces chitinase in the rat

<p>Abstract</p> <p>Background</p> <p>We previously demonstrated that chronic pulmonary infection with <it>Cryptococcus neoformans </it>results in enhanced allergic inflammation and airway hyperreactivity in a rat model. Because the cell wall of <it>C. neoformans </it>consists of chitin, and since acidic mammalian chitinase (AMCase) has recently been implicated as a novel mediator of asthma, we sought to determine whether such infection induces chitinase activity and expression of AMCase in the rat.</p> <p>Methods</p> <p>We utilized a previously-established model of chronic <it>C. neoformans </it>pulmonary infection in the rat to analyze the activity, expression and localization of AMCase.</p> <p>Results</p> <p>Our studies indicate that intratracheal inoculation of <it>C. neoformans </it>induces chitinase activity within the lung and bronchoalveolar lavage fluid of infected rats. Chitinase activity is also elicited by pulmonary infection with other fungi (e.g. <it>C. albicans</it>), but not by the inoculation of dead organisms. Enhanced chitinase activity reflects increased AMCase expression by airway epithelial cells and alveolar macrophages. Systemic cryptococcosis is not associated with increased pulmonary chitinase activity or AMCase expression.</p> <p>Conclusion</p> <p>Our findings indicate a possible link between respiratory fungal infections, including <it>C. neoformans</it>, and asthma through the induction of AMCase.</p

Effect of Stocking Density and Sex on Feathering, Body Injury and Breast Meat Quality of Broiler Chikens

The experiment was conducted at the College of Veterinary Medicine and Animal Production of UNESP-Botucatu Campus to evaluate the effect of stocking densities and sex on body injuries and breast meat quality. One thousand nine hundred and fifty day-old Ross chicks were reared until 42 days of age on a randomized factorial arrangement with three stock densities (10, 13 and 16 birds/m²) and two sexes. At 28, 35 and 42 days of age, 15 birds/treatment were sampled to determine feathering percentage related to body weight and 50 birds/treatment to evaluate score feathering. At 42 days of age, all broilers were processed to evaluate body injuries and breast meat quality. Increasing stocking densities decreased feathering and increased body injuries like breast blisters, dermatitis, bruises and scratches. Breast meat yield and breast length width and depth was negatively affected (p<.05) as stocking densities increased.O experimento foi conduzido nas instalações experimentais da Faculdade de Medicina Veterinária e Zootecnia - UNESP, Campus de Botucatu, SP, Brasil, com o objetivo de avaliar o efeito da densidade de criação e do sexo sobre o empenamento, incidência de lesões na carcaça e a qualidade de carne de peito de frangos de corte. Foram utilizados 1950 pintos de corte sexados, da linhagem Ross, distribuídos em um delineamento inteiramente casualizado, com esquema fatorial com 3 densidades (10, 13 e 16 aves/m²) e dois sexos com 5 repetições, sendo que uma foi destinada exclusivamente para reserva, criados até os 42 dias de idade. Aos 28, 35 e 42 dias foram amostradas 3 aves por repetição para a determinação do empenamento através da porcentagem de penas e 10 aves para a determinação do escore de empenamento. Também aos 42 dias de idade todas as aves foram identificadas na pata com anilhas numeradas e submetidas à avaliação da incidência de lesões na pele. Foram escolhidas ao acaso 5 aves por repetição para a determinação da qualidade da carne de peito. Pode-se concluir que o aumento na densidade de criação promoveu uma diminuição na velocidade de empenamento e, conseqüentemente, uma maior incidência de lesões na carcaça. O comprimento, a largura e a espessura do peito foram menores para as aves criadas na maior densidade, e a perda de peso por cozimento foi maior para as aves criadas na maior densidade.000

Applying multicriteria analysis for choosing the best marination for pork

Objective. This research aimed to choose a best marination solution using the Analytic Hierarchy Process (AHP). Materials and methods. Pork meat samples were collected in a commercial slaughterhouse, and they were randomly distributed in four treatments with three different salt contents blend. Color, pH, retention of the solution, exudate and cooking loss, shear force and sensory attributes were assessed and evaluated. Multicriteria analysis using AHP was applied to the results in order to choose the best overall marination solution. Criteria used for selection were the physical and sensory characteristics of meat, and based on these criteria were classified solutions marination. Results. Results showed that the combination of the salts was the best alternative (Na2CO3+NaCl+Na5P3O10), followed by the solutions of (Na2CO3 + NaCl), and (Na5P3O10 + NaCl). Conclusions. All tested solutions with the salts used alone or in combination led to better physical and sensory attributes than the meat not marinated. Key words: Firmness, sodium chloride, sodium tripolyphosphate, texture (Source:CAB)

Ecological Guild Evolution and the Discovery of the World's Smallest Vertebrate

Living vertebrates vary drastically in body size, yet few taxa reach the extremely minute size of some frogs and teleost fish. Here we describe two new species of diminutive terrestrial frogs from the megadiverse hotspot island of New Guinea, one of which represents the smallest known vertebrate species, attaining an average body size of only 7.7 mm. Both new species are members of the recently described genus Paedophryne, the four species of which are all among the ten smallest known frog species, making Paedophryne the most diminutive genus of anurans. This discovery highlights intriguing ecological similarities among the numerous independent origins of diminutive anurans, suggesting that minute frogs are not mere oddities, but represent a previously unrecognized ecological guild