A chromosome‐scale genome assembly of Antheraea pernyi (Saturniidae,Lepidoptera)

Antheraea pernyi is a semi‐domesticated lepidopteran insect species valuable to the silk industry, human health, and ecological tourism. Owing to its economic influence and developmental properties, it serves as an ideal model for investigating divergence of the Bombycoidea super family. However, studies on the karyotype evolution and functional genomics of A. pernyi are limited by scarce genomic resource. Here, we applied PacBio sequencing and chromosome structure capture technique to assemble the first high‐quality A. pernyi genome from a single male individual. The genome is 720.67 Mb long with 49 chromosomes and a 13.77‐Mb scaffold N50. Approximately 441.75 Mb, accounting for 60.74% of the genome, was identified as repeats. The genome comprises 21,431 protein‐coding genes, 85.22% of which were functionally annotated. Comparative genomics analysis suggested that A. pernyi diverged from its common ancestor with A. yamamai ~30.3 million years ago, and that chromosome fission contributed to the increased chromosome number. The genome assembled in this work will not only facilitate future research on A. pernyi and related species but also help to progress comparative genomics analyses in Lepidoptera.     

Advancing Aptamers as Molecular Probes for Cancer Theranostic Applications—The Role of Molecular Dynamics Simulation

Theranostics cover emerging technologies for cell biomarking for disease diagnosis and targeted introduction of drug ingredients to specific malignant sites. Theranostics development has become a significant biomedical research endeavor for effective diagnosis and treatment of diseases, especially cancer. An efficient biomarking and targeted delivery strategy for theranostic applications requires effective molecular coupling of binding ligands with high affinities to specific receptors on the cancer cell surface. Bioaffinity offers a unique mechanism to bind specific target and receptor molecules from a range of non‐targets. The binding efficacy depends on the specificity of the affinity ligand toward the target molecule even at low concentrations. Aptamers are fragments of genetic materials, peptides, or oligonucleotides which possess enhanced specificity in targeting desired cell surface receptor molecules. Aptamer–target binding results from several inter‐molecular interactions including hydrogen bond formation, aromatic stacking of flat moieties, hydrophobic interaction, electrostatic, and van der Waals interactions. Advancements in Systematic Evolution of Ligands by Exponential Enrichment (SELEX) assay has created the opportunity to artificially generate aptamers that specifically bind to desired cancer and tumor surface receptors with high affinities. This article discusses the potential application of molecular dynamics (MD) simulation to advance aptamer‐mediated receptor targeting in targeted cancer therapy. MD simulation offers real‐time analysis of the molecular drivers of the aptamer‐receptor binding and generate optimal receptor binding conditions for theranostic applications. The article also provides an overview of different cancer types with focus on receptor biomarking and targeted treatment approaches, conventional molecular probes, and aptamers that have been explored for cancer cells targeting.     

Efficient deletion of LoxP-flanked selectable marker genes from the genome of transgenic pigs by an engineered Cre recombinase

Genetically modified (GM) pigs hold great promises for pig genetic improvement, human health and life science. When GM pigs are produced, selectable marker genes (SMGs) are usually introduced into their genomes for host cell or animal recognition. However, the SMGs that remain in GM pigs might have multiple side effects. To avoid the possible side effects caused by the SMGs, they should be removed from the genome of GM pigs before their commercialization. The Cre recombinase is commonly used to delete the LoxP sites-flanked SMGs from the genome of GM animals. Although SMG-free GM pigs have been generated by Cre-mediated recombination, more efficient and cost-effective approaches are essential for the commercialization of SMG-free GM pigs. In this article we describe the production of a recombinant Cre protein containing a cell-penetrating and a nuclear localization signal peptide in one construct. This engineered Cre enzyme can efficiently excise the LoxP-flanked SMGs in cultured fibroblasts isolated from a transgenic pig, which then can be used as nuclear donor cells to generate live SMG-free GM pigs harboring a desired transgene by somatic cell nuclear transfer. This study describes an efficient and far-less costly method for production of SMG-free GM pigs.

     

The effect of grazing on winter survival of midday gerbil (Meriones meridianus) of different genders

The objective of this study was to investigate the effects of grazing on midday gerbil (Meriones meridianus) population characteristics and survival of animals of different genders. The experiment used a randomized complete block design and was conducted in Alxa Left Banner, Inner Mongolia, China, in 2002 (The agricultural reclamation plots set up in 1994). From April 2006 to October 2010, midday gerbils were live‐trapped in 3 light grazing plots, 3 overgrazed plots, and 3 grazing exclusion plots. The quantity of vegetation was investigated in the two different grazing intensity areas and grazing exclusion area to determine the relationship between gerbils and plant food availability. The results suggested that there was higher gerbil density, individual body mass, and daily body mass growth rate in the grazing exclusion sites than the other sites across the whole year. Females had higher survival in grazing exclusion areas than in other treatments, but the males’ survival showed the opposite pattern. Our results indicated that grazing negatively influenced the midday gerbil population by reducing food availability. Grazing influenced the survival rates of male midday gerbils positively, but had negative effects on females. The reason for gendered differences in survival rates of midday gerbils requires further investigation.     

Three‐dimensional reconstruction and comparison of vacuolar membranes in response to viral infection

The vacuole is a unique plant organelle that plays an important role in maintaining cellular homeostasis under various environmental stress conditions. However, the effects of biotic stress on vacuole structure has not been examined using three‐dimensional (3D) visualization. Here, we performed 3D electron tomography to compare the ultrastructural changes in the vacuole during infection with different viruses. The 3D models revealed that vacuoles are remodeled in cells infected with cucumber mosaic virus (CMV) or tobacco necrosis virus A Chinese isolate (TNV‐A^C), resulting in the formation of spherules at the periphery of the vacuole. These spherules contain neck‐like channels that connect their interior with the cytosol. Confocal microscopy of CMV replication proteins 1a and 2a and TNV‐A^C auxiliary replication protein p23 showed that all of these proteins localize to the tonoplast. Electron microscopy revealed that the expression of these replication proteins alone is sufficient to induce spherule formation on the tonoplast, suggesting that these proteins play prominent roles in inducing vacuolar membrane remodeling. This is the first report of the 3D structures of viral replication factories built on the tonoplasts. These findings contribute to our understanding of vacuole biogenesis under normal conditions and during assembly of plant (+) RNA virus replication complexes.     

Secondary Structural Transformation of Bovine Lactoferricin Affects Its Antibacterial Activity

Probiotics and Antimicrobial Proteins - Lactoferricin (Lfcin) is a potent antibacterial peptide derived from lactoferrin by pepsin hydrolysis. It was hypothesized that structural transformation of...     

CX3CL1 promotes tumour cell by inducing tyrosine phosphorylation of cortactin in lung cancer

It has been reported that chemokine CX₃CL1 can regulate various tumours by binding to its unique receptor CX₃CR1. However, the effect of CX₃CL1-CX₃CR1 on the lung adenocarcinoma and lung squamous cell carcinoma is still unclear. Here, we showed that CX₃CL1 can further invasion and migration of lung adenocarcinoma A549 and lung squamous cell carcinoma H520. In addition, Western blot and immunofluorescence test indicated CX₃CL1 up-regulated the phosphorylation level of cortactin, which is a marker of cell pseudopodium. Meanwhile, the phosphorylation levels of c-Src and c-Abl, which are closely related to the regulation of cortactin phosphorylation, are elevated. Nevertheless, the src/abl inhibitor bosutinib and mutations of cortactin phosphorylation site could inhibit the promotion effect of CX₃CL1 on invasion and migration of A549 and H520. Moreover, these results of MTT, Hoechst staining and Western blot suggested that CX₃CL1 had no effect on the proliferation and apoptosis of A549 and H520 in vitro. The effects of CX₃CL1 were also verified by the subcutaneous tumour formation in nude mice, which showed that it could promote proliferation and invasion of A549 in vivo. In summary, our results indicated that CX₃CL1 furthered invasion and migration in lung cancer cells partly via activating cortactin, and CX₃CL1 may be a potential molecule in regulating the migration and invasion of lung cancer.     

Gentiopicroside promotes the osteogenesis of bone mesenchymal stem cells by modulation of β-catenin-BMP2 signalling pathway

Osteoporosis is characterized by increased bone fragility, and the drugs used at present to treat osteoporosis can cause adverse reactions. Gentiopicroside (GEN), a class of natural compounds with numerous biological activities such as anti-resorptive properties and protective effects against bone loss. Therefore, the aim of this work was to explore the effect of GEN on bone mesenchymal stem cells (BMSCs) osteogenesis for a potential osteoporosis therapy. In vitro, BMSCs were exposed to GEN at different doses for 2 weeks, whereas in vivo, ovariectomized osteoporosis was established in mice and the therapeutic effect of GEN was evaluated for 3 months. Our results in vitro showed that GEN promoted the activity of alkaline phosphatase, increased the calcified nodules in BMSCs and up-regulated the osteogenic factors (Runx2, OSX, OCN, OPN and BMP2). In vivo, GEN promoted the expression of Runx2, OCN and BMP2, increased the level of osteogenic parameters, and accelerated the osteogenesis of BMSCs by activating the BMP pathway and Wnt/β-catenin pathway, effect that was inhibited using the BMP inhibitor Noggin and Wnt/β-catenin inhibitor DKK1. Silencing the β-catenin gene and BMP2 gene blocked the osteogenic differentiation induced by GEN in BMSCs. This block was also observed when only β-catenin was silenced, although the knockout of BMP2 did not affect β-catenin expression induced by GEN. Therefore, GEN promotes BMSC osteogenesis by regulating β-catenin-BMP signalling, providing a novel strategy in the treatment of osteoporosis.     

Lyciumamide A,a dimer of phenolic amide,protects against NMDA-induced neurotoxicity and potential mechanisms in vitro

Journal of Molecular Histology - Currently, the excessive activation of N-methyl-D-aspartate receptors (NMDARs) is considered to be a crucial mechanism of brain injury. Lycium barbarum A (LyA) is a...     

网隔栽培法对生姜姜瘟病防治及产量的影响

姜瘟病是由青枯雷尔氏菌(Ralstoniasolanacearum)引起的一种细菌性病害,被称为生姜种植产业的“癌症”.本试验设计了一种“网隔栽培法”,并探索其对土传姜瘟病发病率和生姜产量的影响.结果表明,经过连续3年的田间验证,相比传统栽培法,“网隔栽培法”种植可显著降低姜瘟病的发病率,平均减少了6.08个百分点,平均防治效果达到了48.33%;同时,生姜产量平均增加了13.21%.这种“短行播种、纵横开沟、深沟隔病”的“网隔栽培法”为姜瘟病的绿色防控提供了新方案,也为其他蔬菜、中药材等植物的土传病害防治提供了新的借鉴思路.