Identification of genes related to growth traits from transcriptome profiles of duck breast muscle tissue.

The growth and development of duck skeletal muscle is an important economic trait that is genetically regulated. The internal mechanism underlying the regulation of skeletal muscle growth and development in ducks remains unclear. The purpose of this study was to identify candidate genes related to the growth of duck skeletal muscle. RNA-sequencing technology was used to compare the transcriptome of duck breast muscles in an F2 population with the high breast muscle rate (HB) and the low breast muscle rate (LB). A total of 14,522 genes were confirmed to be expressed in the breast muscle, and 173 differentially expressed genes (DEGs) were identified between the HB and LB groups. Functional analysis showed that these DEGs were mainly involved in biological processes and pathways of fat metabolism and muscle growth, especially the FABP3 and MYL4 involved in the PPAR signaling pathway and cardiac muscle contraction pathway. These findings deepened our understanding of the molecular mechanisms involved in muscle growth in ducks and provided a theoretical basis for improving duck production and breeding of ducks.

Characterization and expression of MUSTN1 gene from different duck breeds.

Muscle growth rate and muscle mass are important economic traits in animal production. Musculoskeletal embryonic nuclear protein 1 (MUSTN1) gene has been implicated in myofusion as well as skeletal muscle growth and repair; however, the exact role and expression of MUSTN1 in different duck breeds are not fully understood. To gain insights into the biological functions of MUSTN1 in skeletal muscle development, the MUSTN1 coding sequence of Pekin ducks (BD) and Cherry Valley ducks (CD) was compared to various other animals using the Editseq in DNAstar and MEGA software. The results showed that the duck had the highest homology with chicken. The RT-qPCR and western blot were performed to estimate the mRNA and protein expression pattern of MUSTN1 in leg muscles of BD and CD at 3 and 6-weeks of age. At 3 weeks of age, the mRNA and protein expression levels of MUSTN1 were significantly higher in BD than in CD (p < 0.05). At 6 weeks, the expression level was higher in BD than in CD. In conclusion, MUSTN1 might play a key role in positive regulation of muscle growth and development of ducks.

Atomic Identification of Interfaces in Individual Core@shell Quantum Dots.

CdSe@CdS Core@shell quantum dots (QDs) have been widely studied in recent years, due to their architecture which allows to tailor properties by controlling structure and composition. However, since CdSe and CdS have the same crystal structure, same cations, and similar lattice parameters, it is very challenging to image the interface. Herein, high-resolution transmission electron microscopy, high-angle annular dark-field imaging, and energy-dispersive X-ray spectroscopy elemental mapping are combined to characterize the core@shell structure and identify the interface in the CdSe@CdS QDs with different CdS shell thicknesses. By examining changes in lattice spacing in an individual CdSe@CdS quantum dot, the atomic core@shell interface is identified. For thin-shelled QDs, an ideal coherent interface forms between core and shell due to the small lattice mismatch, and the lattice spacing remains unchanged at the core and shell regions. For thick-shelled QDs, the lattice spacing is different at the core and shell regions, while the heterostructured interface is still coherent and cannot be clearly imaged. As the shell thickness further increases, a sharp core@shell interface appears. The results define an approach to characterize the heterostructure of two materials with the same crystalline structure and cations.

Identification of key genes and pathways associated with duck (Anas platyrhynchos) embryonic skin development using weighted gene co-expression network analysis.

Skin and feather follicle morphogenesis are important processes for duck development; however, the mechanisms underlying morphogenesis at the embryonic stage remain unclear. To improve the understanding of these processes, we used transcriptome and weighted gene co-expression network analyses to identify the critical genes and pathways involved in duck skin development. Five modules were found to be the most related to five key stages in skin development that span from embryonic day 8 (E8) to postnatal day 7 (D7). Using STEM software, 6519 genes from five modules were clustered into 10 profiles to reveal key genes. Above all, we obtained several key module genes including WNT3A, NOTCH1, SHH, BMP2, NOG, SMAD3, and TGFß2. Furthermore, we revealed that several pathways play critical roles throughout the skin development process, including the Wnt pathway and cytoskeletal rearrangement-related pathways, whereas others are involved in specific stages of skin development, such as the Notch, Hedgehog, and TGF-beta signaling pathways. Overall, this study identified the pathways and genes that play critical roles in skin development, which may provide a basis for high-quality down-type meat duck breeding.

Circular RNA expression profiling reveals that circ-PLXNA1 functions in duck adipocyte differentiation.

Adipocytes are derived from pluripotent mesenchymal stem cells through adipogenesis. Pre-adipocyte differentiation in poultry greatly influences fat deposition and meat quality. Circular RNAs (circRNAs) have an important function in cancer and some differentiation processes. Herein, high-throughput transcriptome sequencing was used to detect circRNAs present in cherry valley duck pre-adipocyte and adipocyte differentiation over 3 days. We identified 9,311 circRNAs and 141 differentially expressed circRNAs. Sequencing results were verified through qRT-PCR using seven randomly selected circRNAs, and competing endogenous RNA (ceRNA) networks were exhibited by ten important circRNAs in duck adipocyte differentiation. circRNA plexin A1 (circ-PLXNA1) was detected in duck adipocytes and mainly expressed in adipose, leg muscle and liver. Inhibition of circ-PLXNA1 limited the differentiation of duck adipocyte. There were four corresponding miRNAs for circ-PLXNA1 and 313 target genes for those miRNAs. CeRNA"circ-PLXNA1/miR-214/CTNNB1 axis" was focused and verified by a dual-luciferase reporter experiment. After co-transfection of cells with si-circ-PLXNA1 and miR-214 mimics, the expression level of CTNNB1 was down-regulated, triglyceride content and the adipogenic capacity of preadipocytes decreased. While there were no significant change after si-CTNNB1 transfection. All these results provide further insight into the circRNAs, especially for circ-PLXNA1 in duck adipocyte differentiation.

Effect of nanocavities on Ge nanoclustering and out-diffusion in SiO2.

Germanium nanocrystals (Ge-ncs) were synthesized by implantation of Ge+ ions into the fused silica, followed by a thermal annealing at 1000 °C. High-resolution transmission electron microscopy was employed to characterize both the morphology of the formed Ge-ncs and the evolution of their depth-distribution as a function of annealing durations. The formation of nanocavities in the vicinity of nanocrystal/SiO2 interface is evidenced, as well as their influence on the release of the compressive stress exerted on Ge-ncs by surrounding SiO2. Some Ge-ncs are found inside nanocavities, and can move into the implanted layer through a nanocavity-assisted diffusion mechanism. This finding sheds light on a new process that can explain the non-uniformity of the Ge-nanocrystal spatial distribution.

Mechanistical investigation on the self-enhanced photocatalytic activity of CuO/Cu2O hybrid nanostructures by density functional theory calculations.

The photocatalytic mechanism of a Cu2O/CuO hybrid system is disclosed in detail by density functional theory (DFT) calculations. The synergistic relationship of the two counterparts is confirmed by hydrogen peroxide (H2O2) formation on the CuO nanowires and dissociation on the Cu2O nanoparticles; this enables the system to self-sufficiently produce hydroxyl radicals, which is highly efficient in the photocatalytic degradation of methyl orange. The exposed surfaces are found to be crucial in the cooperative photocatalytic system, especially the Cu2O(111) surface, in the dissociation of H2O2. The distinct positions of the conduction band minimum and valence band maximum for CuO and Cu2O and synergic surface reactions enable the effective utilization of the electrons and holes generated by visible-light irradiation. Our results will contribute to a greater understanding of the specific mechanism of photodegradation catalyzed by Cu2O/CuO heterostructures, which may lead to promising directions in structure optimization for photocatalysts with high photocatalytic efficiency.