Equivalent potential of water for the electronic structure of glycine

First-principles, all-electron, ab initio calculations have been performed to construct an equivalent potential of water for the electronic structure of glycine (Gly) in solution. The calculation involved three steps. The first step was to search for the minimum-energy geometric structure of the Gly + nH₂O system. The second step was to calculate the electronic structure of Gly with the potential of water molecules via the self-consistent cluster-embedding method (SCCE), based on the result obtained in the first step. The last step was to calculate the electronic structure of Gly with the potential of dipoles after replacing the water molecules with dipoles. The results show that the occupied molecular orbitals of Gly are raised by about 0.0524 Ry on average due to the effect of water. The effect of water can be simulated well using the dipole potential. The equivalent potential obtained can be applied directly to electronic structure calculations of proteins in solution using the SCCE method.     

Research progress on the immune mechanism of the silkworm Bombyx mori

The silkworm Bombyx mori L., representing an important economic insect and one of the best models for studying insect immunity, possesses an efficient and sophisticated innate immune system against invasive microorganisms. The innate immune system basically includes humoural immunity and cellular immunity. The humoural immunity, which functions via molecules including humoural factors, lysozymes, phenoloxidase, hemolin, lectins and, in particular, antimicrobial peptides, plays a central role in eliminating the invading pathogens. The cellular immunity is primarily carried out and mediated by plasmatocytes and granular cells of haemocytes in the haemolymph, usually followed by melanization. Additionally, apoptosis, a primary viral defence for insects lacking adaptive immunity, comprises an important part of the silkworm immune system. Currently, there is still the lack of a comprehensive and systematic understanding of the molecular mechanisms of silkworm immunity. We review the latest research progress on silkworm immune mechanisms, including phenoloxidase‐dependent melanization and apoptosis, which is conducive to improving our understanding of the silkworm immune mechanism, clarifying the relationship of various immune mechanisms, and also providing a theoretical basis and reference for the future research of insect immunity.     

SDX on the X chromosome is required for male sex determination

Dear Editor, Sex determination is one of the most fundamental develop-ment processes,as gender is the first and most important identity of human.In most mammals...     

Effect of Water Content on Glass Transition and Protein Aggregation of Whey Protein Powders During Short-Term Storage

The objectives of this study were to investigate the moisture-induced protein aggregation of whey protein powders and to elucidate the relationship of protein stability with respect to water content and glass transition. Three whey protein powder types were studied: whey protein isolate (WPI), whey protein hydrolysates (WPH), and beta-lactoglobulin (BLG). The water sorption isotherms were determined at 23 and 45°C, and they fit the Guggenheim–Andersson–DeBoer (GAB) model well. Glass transition was determined by differential scanning calorimeter (DSC). The heat capacity changes of WPI and BLG during glass transition were small (0.1 to 0.2 Jg⁻¹ °C⁻¹), and the glass transition temperature (T _g) could not be detected for all samples. An increase in water content in the range of 7 to 16% caused a decrease in T _g from 119 down to 75°C for WPI, and a decrease from 93 to 47°C for WPH. Protein aggregation after 2 weeks’ storage was measured by the increase in insoluble aggregates and change in soluble protein fractions. For WPI and BLG, no protein aggregation was observed over the range of 0 to 85% RH, whereas for WPH, ∼50% of proteins became insoluble after storage at 23°C and 85% RH or at 45°C and ≥73% RH, caused mainly by the formation of intermolecular disulfide bonds. This suggests that, at increased water content, a decrease in the T _g of whey protein powders results in a dramatic increase in the mobility of protein molecules, leading to protein aggregation in short-term storage.     

Plasma metabonomics as a novel diagnostic approach for major depressive disorder

Major depressive disorder (MDD) is a socially detrimental psychiatric disorder, contributing to increased healthcare expenditures and suicide rates. However, no empirical laboratory-based tests are available to support the diagnosis of MDD. In this study, a NMR-based plasma metabonomic method for the diagnosis of MDD was tested. Proton nuclear magnetic resonance ((1)H NMR) spectra of plasma sampled from first-episode drug-na??ve depressed patients (n = 58) and healthy controls (n = 42) were recorded and analyzed by orthogonal partial least-squares discriminant analysis (OPLS-DA). The OPLS-DA score plots of the spectra demonstrated that the depressed patient group was significantly distinguishable from the healthy control group. Moreover, the method accurately diagnosed blinded samples (n = 26) in an independent replication cohort with a sensitivity and specificity of 92.8% and 83.3%, respectively. Taken together, NMR-based plasma metabonomics may offer an accurate empirical laboratory-based method applicable to the diagnosis of MDD.