L'Auto-vélo : automobilisme, cyclisme, athlétisme, yachting, aérostation, escrime, hippisme / dir. Henri Desgranges

29 mai 19041904/05/29 (A5,N1325)

Insights into the Biogenic Amine Metabolic Landscape during Industrial Semidry Chinese Rice Wine Fermentation

Inspired by concerns about food safety, the metabolic landscape of biogenic amines (BAs) was elucidated during industrial semidry Chinese rice wine fermentation. The main fermentation process represented the largest contribution to BA formation, which corresponded to 69.1% (54.3 mg/L). Principal component analysis revealed that total acid and ethanol were strongly correlated with BAs, indicating that BA formation favored acidic and stressful conditions. Other than putrescine (PUT), spermidine (SPD), and spermine (SPM), 5 BAs exhibited strong relationships with the precursor amino acids (<i>R</i>² > 0.85). PUT was mainly decarboxylated from arginine (89.6%) whereas SPD (100%) and SPM (83.1%) were obtained from ornithine. Interestingly, some SPD could convert back to PUT (24.3%). All 8 BAs showed good relationships with lactic acid bacteria (LAB) (<i>R</i>² around 0.75). Moreover, among the five main LAB genera, <i>Lactobacillus</i> had a positive correlation with BA formation

Mixed Starter Culture Regulates Biogenic Amines Formation via Decarboxylation and Transamination during Chinese Rice Wine Fermentation

The utilization of amine-negative starter based on an understanding of nitrogen metabolism is a useful method for controlling biogenic amine (BA) in Chinese rice wine (CRW) fermentation. The contribution of brewing materials to protein degradation was analyzed; wheat Qu protein had no effect, and yeast autolysis generated 10% amino nitrogen. Milling degree of rice was strongly correlated with BAs formation (<i>R</i>² = 0.99). Subsequently, Lactobacillus plantarum and Staphylococcus xylosus were coinoculated as amine-negative starter at an optimized ratio of 1:2. Coinoculation induced a significant reduction in total BAs (43.7%, 44.5 mg L^–1), putrescine (43.0%, 20.4 mg L^–1), tyramine (42.8%, 14.3 mg L^–1), and histamine (42.6%, 3.5 mg L^–1) content. Notably, BAs degradation ability of Staphylococcus xylosus was stronger than the suppression effect of Lactobacillus plantarum, and higher lactic acid bacteria (LAB) amount has a positive correlation with lower BAs content. Overall, mixed strains exerted a synergistic effect in lowering BAs accumulation via decarboxylation and transamination

Orcein-Related Small Molecule O4 Destabilizes hIAPP Protofibrils by Interacting Mostly with the Amyloidogenic Core Region

The accumulation of the human islet amyloid polypeptide (hIAPP) deposits in the pancreas is regarded as an important factor that leads to the depletion of islet β-cells and islet transplantation failure. In recent experiments, it was reported that a small organic molecule O4 inhibits the formation of hIAPP1-37 oligomers and fibrils. However, the interaction between O4 molecules and hIAPP oligomers is largely unknown on the atomic level. In this work, we studied the influence of O4 molecules on fibril-like hIAPP pentamer and decamer by performing atomistic molecular dynamics simulations. Our results show that O4 molecules mostly bind to the amyloid core region spanning residues 22NFGAI26 for both hIAPP pentamer and decamer, which leads to the local disruption of interpeptide β-sheets. The calculation of contact probability and binding energy indicates that the binding of O4 molecules is mostly driven by aromatic stacking and hydrophobic interactions. Our work reveals the detailed disruption mechanism of full-length hIAPP protofibrils by O4 molecules and may be helpful to the design of more efficient inhibitors against hIAPP aggregation

<i>De novo</i> characterization of microRNAs in oriental fruit moth <i>Grapholita molesta</i> and selection of reference genes for normalization of microRNA expression

<div><p>MicroRNAs (miRNAs) are a group of endogenous non-coding small RNAs that have critical regulatory functions in almost all known biological processes at the post-transcriptional level in a variety of organisms. The oriental fruit moth <i>Grapholita molesta</i> is one of the most serious pests in orchards worldwide and threatens the production of Rosacea fruits. In this study, a <i>de novo</i> small RNA library constructed from mixed stages of <i>G</i>. <i>molesta</i> was sequenced through Illumina sequencing platform and a total of 536 mature miRNAs consisting of 291 conserved and 245 novel miRNAs were identified. Most of the conserved and novel miRNAs were detected with moderate abundance. The miRNAs in the same cluster normally showed correlated expressional profiles. A comparative analysis of the 79 conserved miRNA families within 31 arthropod species indicated that these miRNA families were more conserved among insects and within orders of closer phylogenetic relationships. The KEGG pathway analysis and network prediction of target genes indicated that the complex composed of miRNAs, clock genes and developmental regulation genes may play vital roles to regulate the developmental circadian rhythm of <i>G</i>. <i>molesta</i>. Furthermore, based on the sRNA library of <i>G</i>. <i>molesta</i>, suitable reference genes were selected and validated for study of miRNA transcriptional profile in <i>G</i>. <i>molesta</i> under two biotic and six abiotic experimental conditions. This study systematically documented the miRNA profile in <i>G</i>. <i>molesta</i>, which could lay a foundation for further understanding of the regulatory roles of miRNAs in the development and metabolism in this pest and might also suggest clues to the development of genetic-based techniques for agricultural pest control.</p></div

The relationship between rate of larval survival and guarding duration.

<p>Logistic regression: R² = 0.656, guarding duration coefficients = 0.951, constant coefficients = 1.563; ANOVA <i>F</i>_1,47 = 89.778, <i>P</i><0.001.</p

The relationship between egg that were dying and days from oviposition.

<p>The same letter at the data point indicates a lack of significant difference (Tukey multiple comparisons test, P≥0.05).</p

Temperature-Dependent Conformational Properties of Human Neuronal Calcium Sensor‑1 Protein Revealed by All-Atom Simulations

Neuronal calcium sensor-1 (NCS-1) protein has orthologues from <i>Saccharomyces cerevisiae</i> to human with highly conserved amino acid sequences. NCS-1 is an important factor controlling the animal’s response to temperature change. This leads us to investigate the temperature effects on the conformational dynamics of human NCS-1 at 310 and 316 K by all-atom molecular dynamics (MD) simulations and dynamic community network analysis. Four independent 500 ns MD simulations show that secondary structure content at 316 K is similar to that at 310 K, whereas the global protein structure is expanded. Loop 3 (L3) adopts an extended state occuping the hydrophobic crevice, and the number of suboptimal communication paths between residue D176 and V190 is reduced at 316 K. The dynamic community network analysis suggests that the interdomain correlation is weakened, and the intradomain coupling is strengthened at 316 K. The elevated temperature reduces the number of the salt bridges, especially in C-domain. This study suggests that the elevated temperature affects the conformational dynamics of human NCS-1 protein. Comparison of the structural dynamics of R102Q mutant and Δ176–190 truncated NCS-1 suggests that the structural and dynamical response of NCS-1 protein to elevated temperature may be one of its intrinsic functional properties

Survival of offspring in different groups.

<p>ETL, egg to larval stage; LTC, larval to cocoon stage; CTA, cocoon to adult stage.</p><p>1, whole-stage guarding group; 2, non-guarding group; 3, egg-guarding hiatus group; 4, larva-guarding hiatus group; 5, cocoon-guarding hiatus group; 6, multiparous stepmother-guarding group; 7, nulliparous stepmother-guarding group. The presence of the same letter after the mean±SE indicates a lack of significant difference within group (Scheffe multiple comparisons test, <i>P</i>≥0.05).</p

The relationship between rate of egg survival and guarding duration.

<p>Logistic regression: R² = 0.842, guarding duration coefficients = 0.944, constant coefficients = 1.569; ANOVA <i>F</i>_1,40 = 212.935, <i>P</i><0.001.</p