A functional variant in the stearoyl-CoA desaturase (SCD) gene promoter affects gene expression in ovine muscle

The nutritional quality of lambs may be improved with increased stearoyl-CoA desaturase (SCD) gene expression, which increases the desaturation of stearic acid to oleic acid. The aim of this study was to evaluate the effect of the rs412429481 (FJ513370: g.31C > A) SNP located at the SCD gene on the functionality of the gene in lambs reared under different production systems. The effect of the rs412429481 SNP on gene expression in Rasa Aragonesa male lambs slaughtered at 22–24 kg was studied in two experiments. In Experiment 1 (n = 44), the semitendinosus muscle of lambs grazing alfalfa (ALF) or fed concentrates indoors (IND) was analysed; in Experiment 2 (n = 48), the semitendinosus and longissimus thoracis muscles of lambs that received supplementation with dl-a-tocopheryl acetate for different finishing periods were used. In Experiment 1, the effect of the rs412429481 SNP on the expression of the SCD gene in the semitendinosus muscle depended on the feeding group (P < 0.001), as it had no effect in ALF lambs, but CA lambs had greater SCD expression than CC lambs under the IND conditions. Moreover, ALF lambs showed lower levels of SCD gene expression than IND lambs (P < 0.05). In Experiment 2, gene expression was affected by the rs412429481 SNP in both muscles. Animals carrying the C- allele showed a lower expression rate than animals carrying the A- allele. These different expression levels were not associated with changes in the DNA methylation pattern or by the binding of specific nuclear proteins. Finally, we confirmed these results by luciferase assays, demonstrating that the SCD promoter containing the A variant had a 23.9% higher activity than the promoter containing the C variant

Role of the repeat expansion size in predicting age of onset and severity in RFC1 disease

RFC1 disease, caused by biallelic repeat expansion in RFC1, is clinically heterogeneous in terms of age of onset, disease progression and phenotype. We investigated the role of the repeat size in influencing clinical variables in RFC1 disease. We also assessed the presence and role of meiotic and somatic instability of the repeat. In this study, we identified 553 patients carrying biallelic RFC1 expansions and measured the repeat expansion size in 392 cases. Pearson’s coefficient was calculated to assess the correlation between the repeat size and age at disease onset. A Cox model with robust cluster standard errors was adopted to describe the effect of repeat size on age at disease onset, on age at onset of each individual symptoms, and on disease progression. A quasi-Poisson regression model was used to analyse the relationship between phenotype and repeat size. We performed multivariate linear regression to assess the association of the repeat size with the degree of cerebellar atrophy. Meiotic stability was assessed by Southern blotting on first-degree relatives of 27 probands. Finally, somatic instability was investigated by optical genome mapping on cerebellar and frontal cortex and unaffected peripheral tissue from four post-mortem cases. A larger repeat size of both smaller and larger allele was associated with an earlier age at neurological onset [smaller allele hazard ratio (HR) = 2.06, P < 0.001; larger allele HR = 1.53, P < 0.001] and with a higher hazard of developing disabling symptoms, such as dysarthria or dysphagia (smaller allele HR = 3.40, P < 0.001; larger allele HR = 1.71, P = 0.002) or loss of independent walking (smaller allele HR = 2.78, P < 0.001; larger allele HR = 1.60; P < 0.001) earlier in disease course. Patients with more complex phenotypes carried larger expansions [smaller allele: complex neuropathy rate ratio (RR) = 1.30, P = 0.003; cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) RR = 1.34, P < 0.001; larger allele: complex neuropathy RR = 1.33, P = 0.008; CANVAS RR = 1.31, P = 0.009]. Furthermore, larger repeat expansions in the smaller allele were associated with more pronounced cerebellar vermis atrophy (lobules I–V β = −1.06, P < 0.001; lobules VI–VII β = −0.34, P = 0.005). The repeat did not show significant instability during vertical transmission and across different tissues and brain regions. RFC1 repeat size, particularly of the smaller allele, is one of the determinants of variability in RFC1 disease and represents a key prognostic factor to predict disease onset, phenotype and severity. Assessing the repeat size is warranted as part of the diagnostic test for RFC1 expansion

Structural and morphogenical characteristics of black oats and Italian ryegrass on pasture submitted to two grazing intensities Características estruturais e morfogênicas de aveia-preta e azevém-anual em pastagem submetida a duas intensidades de pastejo

Morphogenical and structural characteristics of black oats (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.) on pastures managed under two grazing intensities were quantified by using marked tiller technique. The expected intensities of disappearance of forage mass initial value were 35% (low) and 65% (high). Experimental animals were sheep and interval among grazing was determined through 300 degree-day thermal sum. The experimental design was completely randomized with two grazing intensities and two replicates. Leaf blades of oats and ryegrass were removed at an average proportion of 57.5% of their initial length for both grazing intensities. Among the morphogenical characteristics of oats, only elongation rate of defoliate leaf differed between grazing intensities, with values of 0.059 and 0.081 cm/degree-day for low and high intensities, respectively. Grazing intensities did not alter structural characteristics of oats mixed with ryegrass and red clover. High grazing intensity enables maintenance of a higher number of ryegrass expanding leaves (1.7 leaves/tiller), thus it is suggested for management of pastures with oats mixed with Italian ryegrass and red-clover on intermittent grazing.<br>As características morfogênicas e estruturais de aveia-preta (Avena strigosa Schreb.) e azevém (Lolium multiflorum Lam.), em pastagem manejada sob duas intensidades de pastejo, foram quantificadas por meio da técnica de perfilhos marcados. As intensidades pretendidas de desaparecimento do valor da massa de forragem inicial foram 35% (baixa) e 65% (alta). Os animais experimentais foram ovinos e o intervalo entre pastejos foi determinado pela soma térmica de 300 graus-dia. O delineamento experimental foi inteiramente casualizado com duas intensidades de pastejo e duas repetições. As lâminas foliares de aveia e azevém foram removidas na proporção média de 57,5% do seu comprimento inicial em ambas as intensidades de pastejo. Entre as características morfogênicas da aveia, apenas a taxa de elongação de lâmina desfolhada diferiu entre as intensidades de pastejo, com valores de 0,059 e 0,081 cm/graus-dia para as intensidades alta e baixa, respectivamente. As intensidades de pastejo não provocaram alterações nas características estruturais da aveia em consorciação com azevém e trevo-vermelho. A intensidade de pastejo alta possibilita a manutenção de maior número de folhas em expansão de azevém (1,7 folhas/perfilho), portanto é recomendável para o manejo de pastagens da aveia em consórcio com azevém e trevo-vermelho sob pastejo intermitente

Enhanced performance in fusion plasmas through turbulence suppression by megaelectronvolt ions

© 2022, The Author(s), under exclusive licence to Springer Nature Limited.Alpha particles with energies on the order of megaelectronvolts will be the main source of plasma heating in future magnetic confinement fusion reactors. Instead of heating fuel ions, most of the energy of alpha particles is transferred to electrons in the plasma. Furthermore, alpha particles can also excite Alfvénic instabilities, which were previously considered to be detrimental to the performance of the fusion device. Here we report improved thermal ion confinement in the presence of megaelectronvolts ions and strong fast ion-driven Alfvénic instabilities in recent experiments on the Joint European Torus. Detailed transport analysis of these experiments reveals turbulence suppression through a complex multi-scale mechanism that generates large-scale zonal flows. This holds promise for more economical operation of fusion reactors with dominant alpha particle heating and ultimately cheaper fusion electricity.N