Associations of protein intake, sources and distribution on muscle strength in community-dwelling older adults living in Auckland, New Zealand

Protein intake, sources and distribution impact on muscle protein synthesis and muscle mass in older adults. However, it is less clear whether dietary protein influences muscle strength. Data were obtained from the Researching Eating Activity and Cognitive Health (REACH) study, a cross-sectional study aimed at investigating dietary patterns, cognitive function and metabolic syndrome in older adults aged 65–74 years. Dietary intake was assessed using a 4-d food record and muscle strength using a handgrip strength dynamometer. After adjusting for confounders, in female older adults (n 212), total protein intake (β = 0⋅22, P < 0⋅01); protein from dairy and eggs (β = 0⋅21, P = 0⋅03) and plant food sources (β = 0⋅60, P < 0⋅01); and frequently consuming at least 0⋅4 g/kg BW per meal (β = 0⋅08, P < 0⋅01) were associated with higher BMI-adjusted muscle strength. However, protein from meat and fish intake and the coefficient of variance of protein intake were not related to BMI-muscle strength in female older adults. No statistically significant associations were observed in male participants (n = 113). There may be sex differences when investigating associations between protein intake and muscle strength in older adults. Further research is needed to investigate these sex differences

Tricholoma matsutake 1-Ocen-3-ol and methyl cinnamate repel mycophagous Proisotoma minuta (Collembola: Insecta)

Two major volatiles produced by the mycelia and fruiting bodies of Tricholoma matsutake (1-octen-3-ol and methyl cinnamate) repel a mycophagous collembolan, Proisotoma minuta. Aggregation of the collembolans on their diet was significantly inhibited by exposure to 1 ppm methyl cinnamate or 10 to 100 ppm 1-octen-3-ol. The aggregation activity decreased dose-dependently upon exposure to 1-octen-3-ol at concentrations higher than 0.01 ppm. Aggregation in the presence of methyl cinnamate exhibited three phases: no significant effect at concentrations ranging from 0.001 to 0.1 ppm, significant inhibition from 1 to 100 ppm, and strong inhibition at 1,000 ppm. These results may explain why certain collembolan species do not prefer T. matsutake fruiting bodies

Neuronal Conduction of Excitation without Action Potentials Based on Ceramide Production

International audienceBACKGROUND: Action potentials are the classic mechanism by which neurons convey a state of excitation throughout their length, leading, after synaptic transmission, to the activation of other neurons and consequently to network functioning. Using an in vitro integrated model, we found previously that peripheral networks in the autonomic nervous system can organise an unconventional regulatory reflex of the digestive tract motility without action potentials. METHODOLOGY/PRINCIPAL FINDINGS: In this report, we used combined neuropharmacological and biochemical approaches to elucidate some steps of the mechanism that conveys excitation along the nerves fibres without action potentials. This mechanism requires the production of ceramide in membrane lipid rafts, which triggers in the cytoplasm an increase in intracellular calcium concentration, followed by activation of a neuronal nitric oxide synthase leading to local production of nitric oxide, and then to guanosine cyclic monophosphate. This sequence of second messengers is activated in cascade from rafts to rafts to ensure conduction of the excitation along the nerve fibres. CONCLUSIONS/SIGNIFICANCE: Our results indicate that second messengers are involved in neuronal conduction of excitation without action potentials. This mechanism represents the first evidence-to our knowledge-that excitation is carried along nerves independently of electrical signals. This unexpected ceramide-based conduction of excitation without action potentials along the autonomic nerve fibres opens up new prospects in our understanding of neuronal functioning

Physicochemical and biochemical characterization of ripening injujube (#Ziziphus mauritiana# Lamk) fruits from two accessions grown in Guadeloupe

International audienceJujube fruits (Ziziphus mauritiana Lamk) from two accessions grown in Guadeloupe were harvested andsampled at five ripening stages, from green to reddish-brown in colour. Their physiological character-istics were then investigated. Ascorbic acid increased with ripening until stage 4, to 463 mg/100 g and168 mg/100 g dry weight, for cultivars P3 and P5, respectively. Likewise, ethylene production increaseduntil stage 4, to 121 \ₗ/kg/h and 116 \ₗ/kg/h, for cultivars P3 and P5, respectively. High and transientsucrose accumulation was observed during ripening of P3 fruits, concomitantly with low and constantglucose and fructose contents. P5 fruits also accumulated sucrose transiently but at a lower level than P3fruits, with a marked decrease at the end of ripening. In contrast to P3 fruit, glucose and fructose accu-mulated continuously to high levels during P5 fruit ripening. These data suggested differential sucrosemetabolism during ripening of these fruits. Postharvest treatments with 1-MCP and acetylene were alsoperformed on the three first ripening stages of both cultivars P3 and P5. On the basis of the findings, wediscuss the climacteric behaviour of the P3 and P5 ripening process. (Résumé d'auteur) AD -; CIRAD-PERSYST-UMR Qualisud (FRA); CIRAD-PERSYST-UMR Qualisud (GLP); Université de la Réunion (REU); CIRAD-PERSYST-UMR Qualisud (FRA); CIRAD-PERSYST-UMR Qualisud (GLP