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3-phosphoinositide-dependent protein kinase-1 (PDK-1) is a key kinase regulating the activity of the PI3K/AKT pathway and a major regulator of the AGC protein kinase family. It is essential in the physiological activities of cells, embryonic development, individual development and immune response. In this study, we have identified for the first time an analogue of PDK-1 in the most primitive vertebrate, lamprey, and named it PDK-1-like. The protein sequence similarity of lamprey PDK-1-like to human, mouse, chicken, African xenopus and zebrafish PDK-1 were 64.4 %, 64.5 %, 65.0 %, 61.3 % and 63.2 %, respectively. The phylogenetic tree showed that PDK-1-like of lamprey were located at the base of the vertebrate branch, in line with the trend of biological evolution. Meanwhile, homology analysis showed that PDK-1 proteins across species shared a conserved kinase structural domain and a Pleckstrin Homology (PH) domain. Genomic synteny analysis revealed that the large-scale duplication blocks were not found in lamprey genome and neighbor genes of lamprey PDK-1-like presented dramatic differences compared with jawed vertebrates. More importantly, qPCR analysis showed that PDK-1-like was widely expressed in lamprey. Its mRNA expression levels varied in response to different pathogenic stimuli, and its expression was generally up-regulated under Polyinosinic-Polycytidylic acid (Poly(I:C)) stimulation. Pearson's correlation analysis showed that PDK-1-like was involved in co-expressed with MyD88-independent TLR-3 pathway during the immune response of lamprey, instead of MyD88-dependent TLR-3 pathway. In summary, our composite results offer valuable clues to the origin and evolution of PDK-1, and imply that PDK-1 s are among the most ancestral immune regulators in vertebrates. [ABSTRACT FROM AUTHOR]

The practical application of Si-based materials has been impeded by poor cycling stability. The cage-like silicon/carbon microspheres were fabricated via a series of procedures: the allometric nucleation, magnesiothermic reduction and selective etching. The microstructure, morphology and electrochemical performance for cage-like silicon/carbon microspheres were investigated by X-ray photoelectron spectra, scanning electron microscopy, transmission electron microscopy and galvanostatic charge-discharge tests. The cage-like carbon shell can effectively absorb the volume expansion and restrain the pulverization for silicon electrodes due to its excellent flexibility and toughness, and particular structure. The cage-like silicon/carbon microspheres reveal an outstanding charge capacity of 1926 mA h g−1 at 0.1 C, and still remain 1790 mA h g−1 after 200 cycles. They exhibit an excellent rate capacity of 916 mA h g−1 and capacity retention of 96% after 1000 cycles at 5 C. The design strategy of the cage-like carbon shell structure offers a novel path for improving the electrochemical performance of silicon-based materials. • The CSCMs can effectively prevent the volume effect and the powdering of Si. • The CSCMs can provide high porosity to facilitate the diffusion of Li+, thereby improving the electronic conductivity. • The remarkable rate performance of CSCMs is obtained because of the unique cage-like core-shell structure. [ABSTRACT FROM AUTHOR]