The invasion of tobacco mosaic virus RNA induces endoplasmic reticulum stress-related autophagy in HeLa cells

The ability of human cells to defend against viruses originating from distant species has long been ignored. Owing to the pressure of natural evolution and human exploration, some of these viruses may be able to invade human beings. If their ‘fresh’ host had no defences, the viruses could cause a serious pandemic, as seen with HIV, SARS (severe acute respiratory syndrome) and avian influenza virus that originated from chimpanzees, the common palm civet and birds, respectively. It is unknown whether the human immune system could tolerate invasion with a plant virus. To model such an alien virus invasion, we chose TMV (tobacco mosaic virus) and used human epithelial carcinoma cells (HeLa cells) as its ‘fresh’ host. We established a reliable system for transfecting TMV-RNA into HeLa cells and found that TMV-RNA triggered autophagy in HeLa cells as shown by the appearance of autophagic vacuoles, the conversion of LC3-I (light chain protein 3-I) to LC3-II, the up-regulated expression of Beclin1 and the accumulation of TMV protein on autophagosomal membranes. We observed suspected TMV virions in HeLa cells by TEM (transmission electron microscopy). Furthermore, we found that TMV-RNA was translated into CP (coat protein) in the ER (endoplasmic reticulum) and that TMV-positive RNA translocated from the cytoplasm to the nucleolus. Finally, we detected greatly increased expression of GRP78 (78 kDa glucose-regulated protein), a typical marker of ERS (ER stress) and found that the formation of autophagosomes was closely related to the expanded ER membrane. Taken together, our data indicate that HeLa cells used ERS and ERS-related autophagy to defend against TMV-RNA

Superpixel-Based Weighted Sparse Regression and Spectral Similarity Constrained for Hyperspectral Unmixing

With the support of spectral libraries, sparse unmixing techniques have gradually developed. However, some existing sparse unmixing algorithms suffer from problems, such as insufficient utilization of spatial information and sensitivity to noise. To solve these problems, this article proposes a novel hyperspectral unmixing algorithm, called superpixel-based weighted sparse regression and spectral similarity constrained unmixing. In the proposed method, a precalculated weight is introduced to help enhance sparsity of abundances, which is obtained from coarse abundance estimation. It also maintains spatial consistency in a local region of a hyperspectral image to mitigate the negative influence of noise. Additionally, the method selects optimal neighborhood pixels in the local region by combining spatial and spectral information and constructs a similarity matrix to explore spectral similarity in the subspace. Meanwhile, superpixel segmentation is considered as an auxiliary method to obtain local regions in the unmixing process. Experiments performed on synthetic and real data demonstrate that the proposed method achieves more accurate abundance estimation than other comparison algorithms

Proteomic Insights into citT-Deletion Induced Metabolic Sensitivity in Bio-Degumming of Ramie Fibers by Bacillus subtilis

ABSTRACTCellulose fibers from ramie is a kind of functional biological material with multipurpose in the textile industry, which called as “China grass.” The degumming of ramie fibers performed with Bacillus subtilis were regulated by response regulator CitT from CitS/CitT two-component system through specifically functioning on the degradation of component pectin. In this study, comparative proteomic analysis was executed to obtain insights into the sensitivity by which the metabolic network induced by the absence of CitT protein, and to further explore the regulatory mechanism during bio-degumming process of ramie fibers. Results showed that 29 differentially expressed proteins were detected from original strain and mutant strain, which were mainly involved in transmembrane transport system, two-component system, and amino acid metabolism. This study demonstrated that the lack of CitT protein could result in the down-regulation of enzymes in histidine biosynthesis pathway, and the up-regulation of enzyme in arginine degradation pathway. This study is the first time to reveal comprehensive information about the regulatory function of CitT protein in bio-degumming of ramie fibers, and may provide important scientific and technological basis for targeted constructing engineering strains in degumming of ramie fibers

Lysyl oxidase-like 1 predicts the prognosis of patients with primary glioblastoma and promotes tumor invasion via EMT pathway

Background Lysyl oxidase enzymes (LOXs), as extracellular matrix (ECM) protein regulators, play vital roles in tumor progression by remodeling the tumor microenvironment. However, their roles in glioblastoma (GBM) have not been fully elucidated. Methods The genetic alterations and prognostic value of LOXs were investigated via cBioPortal. The correlations between LOXs and biological functions/molecular tumor subtypes were explored in The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA). After Kaplan‒Meier and Cox survival analyses, a Loxl1-based nomogram and prognostic risk score model (PRSM) were constructed and evaluated by time-dependent receiver operating characteristic curves, calibration curves, and decision curve analyses. Tumor enrichment pathways and immune infiltrates were explored by single-cell RNA sequencing and TIMER. Loxl1-related changes in tumor viability/proliferation and invasion were further validated by CCK-8, western blot, wound healing, and Transwell invasion assays. Results GBM patients with altered LOXs had poor survival. Upregulated LOXs were found in IDH1-wildtype and mesenchymal (not Loxl1) GBM subtypes, promoting ECM receptor interactions in GBM. The Loxl1-based nomogram and the PRSM showed high accuracy, reliability, and net clinical benefits. Loxl1 expression was related to tumor invasion and immune infiltration (B cells, neutrophils, and dendritic cells). Loxl1 knockdown suppressed GBM cell proliferation and invasion by inhibiting the EMT pathway (through the downregulation of N-cadherin/Vimentin/Snai1 and the upregulation of E-cadherin). Conclusion The Loxl1-based nomogram and PRSM were stable and individualized for assessing GBM patient prognosis, and the invasive role of Loxl1 could provide a promising therapeutic strategy

Significant effect of Ca modification on improving catalytic stability of Cu-catalyst in gas-phase furfural hydrogenation to furfuralcohol

The gas-phase hydrogenation of furfural to furfuralcohol over Cr-free Cu-based catalysts has attracted increasing attention due to its environmentally friendly nature and mild operating conditions. Although reduced pure nano-sized CuO exhibits complete furfural hydrogenation and nearly 100% furfuralcohol selectivity, it suffers from rapid deactivation caused by sintering. In this study, we conducted comparative investigations on the catalytic performance and stability of two Cu-based catalysts: 90%CuO-10%SiO2 and 90%CuO-5%CaO-5%SiO2, in the gas-phase furfural hydrogenation. The reaction is carried out under various conditions, including temperatures ranging from 120 to 170 ℃, LHSVs of 1 to 2.2 h−1, and H2 to furfural molar ratios of 3.5 to 12.5. The results indicate that under optimal conditions, the Ca-modified catalyst achieves nearly complete furfural conversion and almost 100% furfuralcohol selectivity for a test duration of 31 h. In contrast, the unmodified catalyst exhibits stable performance for only seven hours despite the similar initial performance. XRD analysis confirms that the gradual deactivation of both catalysts is attributed to the oxidation of reduced metallic Cu sites to Cu oxides. Further characterizations of the two spent catalysts using HRTEM and XPS analyses, along with DFT calculations, suggest that the presence of Ca in Cu lattices prevents the loss of electrons from low-valence Cu sites or the reduced metallic Cu sites, thus inhibiting their oxidation to high-valence Cu oxides. This phenomenon contributes to suppressing the deactivation of Cu-catalysts in the gas-phase furfural hydrogenation process