Abstract:Nucleolus precursor bodies exist in the oocytes and early embryos, and at present, the few components of nucleolus precursor bodies have been identified because of their less content and compact structures in the oocytes. The complete components of the structure of nucleolus precursor bodies have not been elaborated, thereby clarifying the role of the nucleolus precursor bodies in the early embryonic development remains a challenge. The early view is that the nucleolus precursor bodies do not have the ability to process rRNA and generate ribosomes, but this structure provides the material basis for the formation of fibrillo-granular nucleoli, and therefore enabling the late development of embryos to regain the ability of ribosome generation. Recently, this view has been gradually modified. The transfer experiments based on the micromanipulation of nucleolus precursor bodies have confirmed that the maternal nucleolus precursor bodies play a key role in the early embryonic development and the time window of their actions is between fertilization and pronucleus stage. The nucleolus precursor bodies may participate in the process of chromatin remodeling and maintain centromere stability, furthermore affecting the development of early embryos. This article reviews the structure and function of nucleolus precursor bodies as well as the possible mechanism providing a new idea to profound understanding of the developmental potential of early embryos.

Abstract:Spatial memory is one of basic cognitive abilities for human to explore the world. It is ubiquitous in our thinking and speaking about our living environment. We essentially rely on spatial knowledge about the external environment not only when finding the objects (e.g., keys and cell phones), but also when shopping, working or dating. Given that special memory plays fundamental and important roles in daily life, it is vital to characterize how the brain represents the environment. Using fMRI and electrophysiological techniques to date, many studies have investigated spatial memory processing and neural mechanisms of hippocampus formation and neocortex. In this review, we focus on the key questions about how the brain constructs the cognitive map and which neural circuits are involved for this processing. Future studies to explore neural basis of human spatial memory will need to be highly interdisciplinary and integrative, and may contribute to the diagnosis and intervention of cognitive disorders.

Abstract:After viral and bacterial pathogens enter the cell, they use host proteins to complete their life cycles. Recently, ACBD3 is shown to interact with many pathogen proteins and affect the replication of pathogens. This review will summarize the interplay between ACBD3 and different pathogens, including Aichi virus, Coxsackie virus, poliovirus, hepatitis C virus, human rhinovirus and Salmonella, and discuss the role of ACBD3 in pathogen replication.

Abstract:The strong adhesion of barnacles to underwater facilities causes great fowling, on the other hand, it provides a platform for underwater attachment research. The associated anti-fouling and underwater adhesion techniques are strongly dependent on the understanding of their attachment processes and molecular mechanisms. At present, the macroscopic process of the adhesion of the barnacles has a more in-depth development, including the substrate detection, signal transmission, glue secretion and curing, but the molecular mechanism of the process such as receptor recognition and the regulation of gene are still limited. Biological and biochemical studies have been motivated mainly by understanding the nature of the adhesion, which indicate that the various stages of molecular mechanisms related to anti-fouling and adhesion is essential. In this paper, the focuses are on the common themes and interconnections in three related areas: the process of barnacle attachment, the internal signal molecular response during adhesion, and the mechanism of curing during the process of glue secretion. The existing problems were also given to analyze further possible research.

Abstract:The plant-specific TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) transcription factors are classified into two classes, class Ⅰ and class Ⅱ TCPs according to the shared bHLH TCP domain. Accumulating evidences demonstrate that a subgroup of class Ⅱ CINCINNATA-like (CIN-like) TCP transcription factors plays a vital role in the establishment of plant architecture through modulating hormone biosynthesis and signaling. Recent advances have revealed their unexpected roles in mediating pathogenic effectors-triggered immunity (ETI), suggesting that the widely recognized developmental modulators are involved in fine-tuning plant immunity as well. Although the dissection of the regulatory pathway of CIN-like TCP proteins has begun to shed light on their mechanism of action, a unified and updated view based on the available information is urgently needed. This review aims to summarize the current knowledge about the functions of CIN-like TCPs in various regulatory cascades, and their roles as effector targets with an emphasis on the characterization of the available mutants, TCP interacting factors and the interconnected hormonal networks. Future perspectives for the research of these proteins are also discussed.

Abstract:The aim of this study was to explore the regulatory role of the PI3K/Akt pathway in adipogenic trans-differentiation of myoblasts. C2C12 myoblasts were cultured and, subsequently, induced for adipogenic trans-differentiation. During trans-differentiation, levels of phosphorylated PI3K (P85 and P55 subunits) were increased progressively with early differentiation, but significantly decreased during late-phase differentiation. There were no changes in Akt protein levels, but its phosphorylation levels changed similarly to those of PI3K. Wortmannin treatment of the cells efficiently suppressed PI3K/Akt activation, resulting in significant inhibition of adipogenesis and to varying extents, downregulated expression of several adipogenic genes (PPARγ, C/EBPα, FABP4 and FATP1). In addition, silencing the PI3K gene by siRNA transfection also inhibited adipogenic trans-differentiation in C2C12 cells. Moreover, suppressing both activation and expression of PI3K/Akt induced apoptosis. Taken together, our findings indicated that the PI3K/Akt pathway plays a key role in adipogenic trans-differentiation of myoblasts.

Abstract:Mitotic arrest deficient protein 2 (Mad2) is a typical metamorphic protein, which can adopt two distinct native folds at equilibrium under physiological conditions, an open inactive form (O-Mad2) and a closed active form (C-Mad2). This unusual two-state behavior of Mad2 and their interactions with cognate ligand Cdc20 plays a critical role in spindle assembly checkpoint signaling during mitosis. In this paper, interactions of O-Mad2 and C-Mad2 with TAMRA-Cdc20^121-138 were systematically investigated using fluorescence anisotropy techniques. As a result, the equilibrium dissociation constant of Mad2 two folds binding with Cdc20^121-138 were both within 10^-6 mol/L range in lower ionic strength solutions, and the K_D value of C-Mad2 and Cdc20^121-138 was 5 times lower than that of O-Mad2. While in high ionic strength solution, there was no obvious difference on KD value of C-Mad2 and O-Mad2 binding with Cdc20^121-138. The kinetic experiments suggested that the dissociation rate constant (k_d) between C-Mad2 and TAMRA-Cdc20^121-138 was similar to that of O-Mad2, but the association rate constant (k_a) between C-Mad2 and TAMRA-Cdc20^121-138 was one order of magnitude higher than that of O-Mad2, which suggested that the binding of C-Mad2 with Cdc20^121-138 is thermodynamically more stable and kinetically faster. Studies on interactions between Cdc20 mutants and Mad2 together with influence of ionic strength on their interactions both suggested that the interaction of Mad2 and Cdc20 is possibly not achieved by electrostatic interaction, but through hydrophobic interactions. Our results provide key information for revealing the conformational transition mechanism of metamorphic proteins and their important role in mitosis.

Abstract:Acid-stress chaperone HdeA and its substrate protein, can contribute to pathogenic-bacteria survival by mutual interactions, when bacteria exposed to extremely acidic conditions. To figure out this mechanisms, molecular docking and molecular dynamics simulation were performed in this paper to investigate the binding mode of SurA to HdeA. MM-PBSA method was used to calculate the binding free energy. The interaction mode, H-bond and energy decompositions of the HdeA-SurA complex were firstly analysed. Based on these analysis, the key amino acid residues which are essential for interactions were subsequently determined. Our results may provide a theoretical guidence for exploring binding mechanism between HdeA and substrate as well as a new strategy for the development of new HdeA inhibitors.

Abstract:Shigella flexneri was the most common pathogen causing bacillary dysentery. Thioredoxin-dependent thiol peroxidase (SF2523) proteins was from Shigella flexneri 2a str. 301. It belonged to thioredoxin peroxidase family and played an important role in protecting the biological macromolecule by scavenging active oxygen generated in the process of aerobic metabolism. To understand the underlying mechanism, prokaryotically expressed thioredoxin-dependent thiol peroxidase protein was purified using affinity chromatography and gel filtration, crystallized using the vapour-diffusion method. The crystal grew in a condition consisting of 1.8 mol/L tri-Ammonium citrate, pH 7.0 using 1 g/L protein solution at 289 K. A complete data set was collected from a crystal to 2.75 ? resolution using synchrotron radiation at 100 K. The crystal belonged to space group P2₁2₁2₁, with unit-cell parameters a = 35.80 ?, b = 50.63 ?, c = 88.52 ?, α = β = γ = 90.00°. One molecule was found in the asymmetric unit with a Matthews coefficient of 2.03 ?³/u, corresponding to a solvent content of 39.56%.