ABSTRACT
BACKGROUND: The effect of coronavirus disease 2019 (COVID-19) on adrenal endocrine metabolism in critically ill patients remains unclear. This study aimed to investigate the alterations in adrenal steroidogenic activity, elucidate underlying mechanisms, provide in situ histopathological evidence, and examine the clinical implications. METHODS: The comparative analyses of the adrenal cortices from 24 patients with fatal COVID-19 and 20 matched controls was performed, excluding patients previously treated with glucocorticoids. Several SARS-CoV-2 and its receptors were identified and pathological alterations were examined. Furthermore, histological examinations, immunohistochemical staining and ultrastructural analyses were performed to assess corticosteroid biosynthesis. The zona glomerulosa (ZG) and zona fasciculata (ZF) were then dissected for proteomic analyses. The biological processes that affected steroidogenesis were analyzed by integrating histological, proteomic, and clinical data. Finally, the immunoreactivity of mineralocorticoids and glucocorticoid receptors in essential tissues were quantitatively measured to evaluate corticosteroid responsiveness. FINDINGS: The demographic characteristics of COVID-19 patients were comparable with those of controls, excluding those that affected adrenal function. SARS-CoV-2-like particles were identified in the adrenocortical cells of three patients; however, these particles did not affect cellular morphology or steroid synthesis compared with those in SARS-CoV-2-negative specimens. Although the adrenals exhibited focal necrosis, vacuolization, microthrombi, and inflammation, widespread degeneration was not evident. Notably, corticosteroid biosynthesis was significantly enhanced in both the ZG and ZF of COVID-19 patients. The increase in the inflammatory response and cellular differentiation in the adrenal cortices of patients with critical COVID-19 was positively correlated with heightened steroidogenic activity. Additionally, the appearance of more dual-ZG/ZF identity cells in COVID-19 adrenals was in accordance with the increased steroidogenic function. However, activated mineralocorticoid and glucocorticoid receptors in vital tissues were markedly reduced in patients with critical COVID-19. INTERPRETATION: Critical COVID-19 was characterized by potentiated adrenal steroidogenesis, associated with exacerbation of inflammation, differentiation and the presence of dual-ZG/ZF identity cells. These alterations implied the reduced effectiveness of conventional corticosteroid therapy and underscored the need for evaluation of adrenal axis and the corticosteroid sensitivity.
ABSTRACT
Latent membrane protein 1 (LMP1) is the primary oncoprotein of Epstein-Barr virus (EBV) and plays versatile roles in the EBV life cycle and pathogenesis. Despite decades of extensive research, the molecular basis for LMP1 folding, assembly, and activation remains unclear. Here, we report cryo-electron microscopy structures of LMP1 in two unexpected assemblies: a symmetric homodimer and a higher-order filamentous oligomer. LMP1 adopts a non-canonical and unpredicted fold that supports the formation of a stable homodimer through tight and antiparallel intermolecular packing. LMP1 dimers further assemble side-by-side into higher-order filamentous oligomers, thereby allowing the accumulation and specific organization of the flexible cytoplasmic tails for efficient recruitment of downstream factors. Super-resolution microscopy and cellular functional assays demonstrate that mutations at both dimeric and oligomeric interfaces disrupt LMP1 higher-order assembly and block multiple LMP1-mediated signaling pathways. Our research provides a framework for understanding the mechanism of LMP1 and for developing potential therapies targeting EBV-associated diseases.
ABSTRACT
Defense-associated sirtuin 2 (DSR2) systems are widely distributed across prokaryotic genomes, providing robust protection against phage infection. DSR2 recognizes phage tail tube proteins and induces abortive infection by depleting intracellular NAD+, a process that is counteracted by another phage-encoded protein, DSR Anti Defense 1 (DSAD1). Here, we present cryo-EM structures of Bacillus subtilis DSR2 in its apo, Tube-bound, and DSAD1-bound states. DSR2 assembles into an elongated tetramer, with four NADase catalytic modules clustered in the center and the regulatory-sensing modules distributed at four distal corners. Interestingly, monomeric Tube protein, rather than its oligomeric states, docks at each corner of the DSR2 tetramer to form a 4:4 DSR2-Tube assembly, which is essential for DSR2 NADase activity. DSAD1 competes with Tube for binding to DSR2 by occupying an overlapping region, thereby inhibiting DSR2 immunity. Thus, our results provide important insights into the assembly, activation and inhibition of the DSR2 anti-phage defense system.
Subject(s)
Bacillus subtilis , Bacterial Proteins , Bacteriophages , Cryoelectron Microscopy , Bacillus subtilis/immunology , Bacillus subtilis/genetics , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/immunology , Bacteriophages/genetics , Bacteriophages/immunology , Immune Evasion , Sirtuins/metabolism , Sirtuins/genetics , Viral Proteins/metabolism , Viral Proteins/immunology , Viral Proteins/chemistry , Viral Proteins/genetics , Protein Binding , Models, Molecular , NAD/metabolismABSTRACT
A systematic grasp of the evolution of the spatial and temporal patterns of ecosystem service value (ESV) in the Central Line Project for South-to-North Water Diversion (CLPSNWD) water source area is conducive to deepening the ecological protection and promoting high-quality development of the water source area. In this paper, the dynamically adjusted equivalent factor method is used to reveal the spatial and temporal evolution of ESV in the water source area under strong human activities from 1991 to 2020. The results show that (1) during the 30-year period, urban point expansion increased the construction land area by 63.66 km2, and the degree of fragmentation increased. The water area increased the most, reaching 209.43 km2. (2) The total increase in ESV over the 30-year period was $1434 million, with forests and water accounting for the largest increase, i.e., 98% of the total increase in value. Among the individual service functions, hydrologic regulation generated the most significant service value.
Subject(s)
Ecosystem , Environmental Monitoring , Humans , China , Human Activities , WaterABSTRACT
Water resources are vital to the development of human society, and mastering the law of runoff changes is the basis for achieving sustainable use of water resources. To study the impact of reservoir construction on the changes of downstream river runoff, this paper decomposes the runoff before and after reservoir construction using the CEEMDAN method based on the runoff data from the Huayuankou hydrological station. The fluctuation characteristics of each decomposition series of runoff before and after reservoir construction and the intra-annual variation pattern of runoff are also analyzed by combining multi-time information entropy and coefficient of variation. The results show that after the operation of the Xiaolangdi Reservoir, the annual runoff variation cycle tends to be flat, and the monthly runoff cycle is significantly reduced. After reservoir construction, the entropy values of each IMF and Res of runoff become larger, the complexity and randomness of runoff changes increase, and predictability decreases. Before and after the operation of the Xiaolangdi Reservoir, the coefficient of variation of runoff were 0.28-1 and 0.38-0.83, the distribution of runoff was more uniform, and the percentage of runoff in the flood season was reduced from 51.51 to 39.89%.
Subject(s)
Floods , Hydrology , Humans , Entropy , Rivers , SeasonsABSTRACT
The actin-rich cortex plays a fundamental role in many cellular processes. Its architecture and molecular composition vary across cell types and physiological states. The full complement of actin assembly factors driving cortex formation and how their activities are spatiotemporally regulated remain to be fully elucidated. Using Dictyostelium as a model for polarized and rapidly migrating cells, we show that GxcM, a RhoGEF localized specifically in the rear of migrating cells, functions together with F-BAR protein Fbp17, a small GTPase RacC, and the actin nucleation-promoting factor WASP to coordinately promote Arp2/3 complex-mediated cortical actin assembly. Overactivation of this signaling cascade leads to excessive actin polymerization in the rear cortex, whereas its disruption causes defects in cortical integrity and function. Therefore, apart from its well-defined role in the formation of the protrusions at the cell front, the Arp2/3 complex-based actin carries out a previously unappreciated function in building the rear cortical subcompartment in rapidly migrating cells.
Subject(s)
Actins , Dictyostelium , Protozoan Proteins , Actin-Related Protein 2-3 Complex/genetics , Actin-Related Protein 2-3 Complex/metabolism , Actins/metabolism , Dictyostelium/genetics , Dictyostelium/metabolism , Signal Transduction , Wiskott-Aldrich Syndrome Protein/metabolism , Protozoan Proteins/genetics , Protozoan Proteins/metabolismABSTRACT
The Xiaolangdi Reservoir is the second largest water conservancy project in China and the last comprehensive water conservancy hub on the mainstream of the Yellow River, playing a vital role in the middle and lower reaches of the Yellow River. To study the effects of the construction of the Xiaolangdi Reservoir (1997-2001) on the runoff and sediment transport in the middle and lower reaches of the Yellow River, runoff and sediment transport data from 1963 to 2021 were based on the hydrological stations of Huayuankou, Gaocun, and Lijin. The unevenness coefficient, cumulative distance level method, Mann-Kendall test method, and wavelet transform method were used to analyze the runoff and sediment transport in the middle and lower reaches of the Yellow River at different time scales. The results of the study reveal that the completion of the Xiaolangdi Reservoir in the interannual range has little impact on the runoff in the middle and lower reaches of the Yellow River and a significant impact on sediment transport. The interannual runoff volumes of Huayuankou station, Gaocun station, and Lijin station were reduced by 20.1%, 20.39%, and 32.87%, respectively. In addition, the sediment transport volumes decreased by 90.03%, 85.34%, and 83.88%, respectively. It has a great influence on the monthly distribution of annual runoff. The annual runoff distribution is more uniform, increasing the runoff in the dry season, reducing the runoff in the wet season, and bringing forward the peak flow. The runoff and Sediment transport have obvious periodicity. After the operation of the Xiaolangdi Reservoir, the main cycle of runoff increases and the second main cycle disappears. The main cycle of Sediment transport did not change obviously, but the closer it was to the estuary, the less obvious the cycle was. The research results can provide a reference for ecological protection and high-quality development in the middle and lower reaches of the Yellow River.
Subject(s)
Environmental Monitoring , Rivers , Water Supply , China , Estuaries , Geologic Sediments/analysis , Geologic Sediments/chemistry , Rivers/chemistry , Seasons , Water/analysisABSTRACT
Hydrogenases are microbial metalloenzymes capable of catalyzing the reversible interconversion between molecular hydrogen and protons with high efficiency, and have great potential in the development of new electrocatalysts for renewable fuel production. Here, we engineered the intact proteinaceous shell of the carboxysome, a self-assembling protein organelle for CO2 fixation in cyanobacteria and proteobacteria, and sequestered heterologously produced [NiFe]-hydrogenases into the carboxysome shell. The protein-based hybrid catalyst produced in E. coli shows substantially improved hydrogen production under both aerobic and anaerobic conditions and enhanced material and functional robustness, compared to unencapsulated [NiFe]-hydrogenases. The catalytically functional nanoreactor as well as the self-assembling and encapsulation strategies provide a framework for engineering new bioinspired electrocatalysts to improve the sustainable production of fuels and chemicals in biotechnological and chemical applications.
Subject(s)
Cyanobacteria , Hydrogenase , Hydrogenase/genetics , Hydrogenase/chemistry , Hydrogenase/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Catalysis , Hydrogen/chemistryABSTRACT
Land use change and ecological sensitivity studies are relevant to the dynamic stability of the overall regional ecological environment. In this study, Nanyang City, a South-North Water Transfer water source area, was used as the study area to analyse land use changes and landscape pattern changes in Nanyang City from 1990 to 2020 based on land use data. Hierarchical analysis (AHP method) was used and combined with six sensitivity factors to conduct a multi-factor comprehensive ecological sensitivity evaluation of Nanyang City. The results show that: (1) between 1990 and 2020, the transfer of water and construction land in Nanyang City was larger, increasing by 30.25% and 99.56% respectively, with a small decrease in the area of cultivated land and a small increase in the area of forest land; the overall rate of land use change in Nanyang City during the 30-year period was first slow and then fast. (2) At the level of patch types, the fragmentation of cultivated land and construction land is the highest; during the study period, the overall fragmentation of the study area tends to decrease; at the level of landscape, each landscape type develops in the direction of equilibrium. (3) The ecological sensitivity increases gradually from the urban cluster in the central plain area to the periphery, with the highly sensitive areas distributed in the water area, the medium sensitive areas in the mountainous area, and the low sensitive areas and insensitive areas in the cultivated land and town planning area.
Subject(s)
Conservation of Natural Resources , Ecosystem , Water , Environmental Monitoring/methods , Forests , Cities , ChinaABSTRACT
The carboxysome is a protein-based nanoscale organelle in cyanobacteria and many proteobacteria, which encapsulates the key CO2-fixing enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and carbonic anhydrase (CA) within a polyhedral protein shell. The intrinsic self-assembly and architectural features of carboxysomes and the semipermeability of the protein shell provide the foundation for the accumulation of CO2 within carboxysomes and enhanced carboxylation. Here, we develop an approach to determine the interior pH conditions and inorganic carbon accumulation within an α-carboxysome shell derived from a chemoautotrophic proteobacterium Halothiobacillus neapolitanus and evaluate the shell permeability. By incorporating a pH reporter, pHluorin2, within empty α-carboxysome shells produced in Escherichia coli, we probe the interior pH of the protein shells with and without CA. Our in vivo and in vitro results demonstrate a lower interior pH of α-carboxysome shells than the cytoplasmic pH and buffer pH, as well as the modulation of the interior pH in response to changes in external environments, indicating the shell permeability to bicarbonate ions and protons. We further determine the saturated HCO3- concentration of 15 mM within α-carboxysome shells and show the CA-mediated increase in the interior CO2 level. Uncovering the interior physiochemical microenvironment of carboxysomes is crucial for understanding the mechanisms underlying carboxysomal shell permeability and enhancement of Rubisco carboxylation within carboxysomes. Such fundamental knowledge may inform reprogramming carboxysomes to improve metabolism and recruit foreign enzymes for enhanced catalytical performance.
Subject(s)
Carbonic Anhydrases , Ribulose-Bisphosphate Carboxylase , Bacterial Proteins/metabolism , Bicarbonates , Carbon/metabolism , Carbon Dioxide/metabolism , Carbonic Anhydrases/metabolism , Hydrogen-Ion Concentration , Organelles/metabolism , Oxygenases/metabolism , Permeability , Protons , Ribulose-Bisphosphate Carboxylase/chemistry , Ribulose-Bisphosphate Carboxylase/metabolismABSTRACT
High-grade serous ovarian cancer (HGSOC) is the most lethal gynecologic malignancy mainly due to its extensive metastasis. Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3), a newly discovered splice variant of solute carrier organic anion transporter family member 1B3 (SLCO1B3), has been reported to be overexpressed in several types of cancer. However, the biological function of Ct-OATP1B3 remains largely unknown. Here, we reveal that Ct-OATP1B3 is overexpressed in HGSOC and promotes the metastasis of HGSOC in vivo and in vitro. Mechanically, Ct-OATP1B3 directly interacts with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an RNA-binding protein, which results in enhancement of the mRNA stability and expression of carnitine palmitoyltransferase 1A (CPT1A) and NADH:Ubiquinone Oxidoreductase Subunit A2 (NDUFA2), leading to increased mitochondrial fatty acid beta-oxidation (FAO) and oxidative phosphorylation (OXPHOS) activities. The increased FAO and OXPHOS activities further facilitate adenosine triphosphate (ATP) production and cellular lamellipodia formation, which is the initial step in the processes of tumor cell migration and invasion. Taken together, our study provides an insight into the function and underlying mechanism of Ct-OATP1B3 in HGSOC metastasis, and highlights Ct-OATP1B3 as a novel prognostic marker as well as therapeutic target in HGSOC.
Subject(s)
Organic Anion Transporters , Ovarian Neoplasms , Fatty Acids , Female , Humans , Ovarian Neoplasms/genetics , Oxidative Phosphorylation , RNA-Binding ProteinsABSTRACT
Acetolactate synthase (AHAS) catalyses the first common step in the biosynthesis pathways of three branched-chain amino acids (BCAAs) of valine, isoleucine and leucine. Here, we characterized one regulatory subunit (VdILV6) and three catalytic subunits (VdILV2A, VdILV2B and VdILV2C) of AHAS from the important cotton Verticillium wilt fungus Verticillium dahliae. Phenotypic analysis showed that VdILV6 knockout mutants were auxotrophic for valine and isoleucine and were defective in conidial morphogenesis, hypha penetration and virulence to cotton, and lost ability of microscletotial formation. The growth of single catalytic subunit gene knockout mutants were significantly inhibited by leucine at higher concentration and single catalytic subunit gene knockout mutants showed significantly reduced virulence to cotton. VdILV2B knockout also led to obviously reduced microscletotial formation and conidial production, VdILV2C knockout led to reduced conidial production. Further studies suggested that both feedback inhibition by leucine and the inhibition by AHAS inhibiting herbicides of tribenuron and bispyribac resulted in significantly down-regulated expression of the four subunit VdILVs genes (VdILV2A, VdILV2B, VdILV2C and VdILV6). Any single catalytic subunit gene knockout led to reduced expression of the other three subunit genes, whereas VdILV6 knckout induced increased expression of the three catalytic subunit genes. VdILV2B, VdILV2C and VdILV6 knockout resulted in increased expression of VdCPC1 regulator gene of the cross-pathway control of amino acid biosynthesis. Taken together, these results indicate multiple roles of four VdILVs genes in the biosynthesis of BCAAs, virulence, fungal growth and development in the filamentous fungi V. dahliae.
Subject(s)
Acetolactate Synthase , Verticillium , Acetolactate Synthase/genetics , Acetolactate Synthase/metabolism , Acremonium , Amino Acids, Branched-Chain , Catalytic Domain/genetics , Fungal Proteins/metabolism , Isoleucine , Lactates , Leucine , Plant Diseases/microbiology , Spores, Fungal , Valine , Virulence/geneticsABSTRACT
The sequence and structure of antioxidant peptides play fundamental roles in their antioxidant functions. However, the structural mechanism of antioxidant peptides is still unclear. In this study, we used quantum calculations to reveal the antioxidant mechanism of the peptide PMRGGGGYHY. PMRGGGGYHY has multiple antioxidant active sites, and two tyrosine residues were determined to be the major active sites. Based on the structure-activity relationships of PMRGGGGYHY, the antioxidant activity of the modified peptide significantly improved by 4.8-fold to 9.73 ± 0.61 µmol TE/µmol. In addition, the removal of glycine residues from PMRGGGGYHY would increase the energy of the HOMOs and simplify the hydrogen bonding network, causing a significant increase in antioxidant activity. The intracellular ROS scavenging ability gradually decreased with decreasing glycine content. This same peptide has very different effects in vitro versus as a cellular antioxidant. This paper provides new insights into the structural mechanism and rational design/modification of novel antioxidant peptides.
Subject(s)
Antioxidants/chemistry , Antioxidants/pharmacology , Oligopeptides/chemistry , Oligopeptides/pharmacology , Amino Acid Sequence , Structure-Activity RelationshipABSTRACT
Compartmentalization is a ubiquitous building principle in cells, which permits segregation of biological elements and reactions. The carboxysome is a specialized bacterial organelle that encapsulates enzymes into a virus-like protein shell and plays essential roles in photosynthetic carbon fixation. The naturally designed architecture, semi-permeability, and catalytic improvement of carboxysomes have inspired rational design and engineering of new nanomaterials to incorporate desired enzymes into the protein shell for enhanced catalytic performance. Here, we build large, intact carboxysome shells (over 90 nm in diameter) in the industrial microorganism Escherichia coli by expressing a set of carboxysome protein-encoding genes. We develop strategies for enzyme activation, shell self-assembly, and cargo encapsulation to construct a robust nanoreactor that incorporates catalytically active [FeFe]-hydrogenases and functional partners within the empty shell for the production of hydrogen. We show that shell encapsulation and the internal microenvironment of the new catalyst facilitate hydrogen production of the encapsulated oxygen-sensitive hydrogenases. The study provides insights into the assembly and formation of carboxysomes and paves the way for engineering carboxysome shell-based nanoreactors to recruit specific enzymes for diverse catalytic reactions.
Subject(s)
Bacterial Proteins/metabolism , Bioreactors , Hydrogen/metabolism , Organelles/metabolism , Bacterial Proteins/genetics , Biocatalysis , Bioengineering , Bioreactors/microbiology , Escherichia coli/genetics , Escherichia coli/metabolism , Genes, Bacterial , Halothiobacillus/genetics , Halothiobacillus/metabolism , Hydrogenase/metabolism , Iron-Sulfur Proteins/metabolism , Nanocapsules/chemistry , Nanocapsules/ultrastructure , Organelles/genetics , Organelles/ultrastructure , Photosynthesis , Ribulose-Bisphosphate Carboxylase/genetics , Ribulose-Bisphosphate Carboxylase/metabolismABSTRACT
Lung cancer is one of most common malignant cancer worldwide. It is emerging that PCYT1A, a rate-limiting enzyme required for the biosynthesis of phosphatidylcholine, is associated with cancer progression. However, the biological functions and underlying molecular mechanisms of PCYT1A in lung adenocarcinoma is still unknown. Here we found that PCYT1A suppressed lung adenocarcinoma cancer cell proliferation and migration. Mechanically, PCYT1A served as a novel negative regulator of mTORC1 signaling. PCYT1A knockdown enhanced the malignant proliferation and migration of lung adenocarcinoma cells by activating mTORC1. The promoting effects of PCYT1A silencing on cell proliferation and migration could be abolished when mTORC1 signaling was inhibited by rapamycin or RAPTOR depletion. Importantly, PCYT1A high expression predicted longer survival of lung cancer patients. The expression of PCYT1A was also negatively correlated with mTORC1 activation in the clinical lung cancer samples. We therefore reveal that PCYT1A suppresses proliferation and migration by inhibiting the mTORC1 signaling pathway in lung adenocarcinoma. PCYT1A shows as a potential promising biomarker in lung adenocarcinoma.
Subject(s)
Adenocarcinoma of Lung/metabolism , Choline-Phosphate Cytidylyltransferase/metabolism , Lung Neoplasms/metabolism , Mechanistic Target of Rapamycin Complex 1/metabolism , Signal Transduction , Adenocarcinoma of Lung/pathology , Cell Line, Tumor , Cell Movement , Cell Proliferation , Humans , Lung Neoplasms/pathologyABSTRACT
PURPOSE: This study sought to identify a disease-related gene in a consanguineous Chinese family in which there were two premature ovarian insufficiency (POI) sisters. METHOD: We used whole-exome sequencing and Sanger sequencing to identify the disease-causing gene. Results were verified using an assay of mutant protein and in silico analyses. RESULT: We identified a novel missense mutation (NM_000303: c.556G>A, p.Gly186Arg) in the PMM2 gene. The two sisters suffer from premature ovarian insufficiency (POI) only and have no other symptoms of congenital disorder of glycosylation type-1a (CDG-Ia). We found that the enzymic activity of the mutant PMM2 protein was reduced by 55.21% (p < 0.05) when compared with wild type, and many in silico tools suggested the mutation is disease-related. CONCLUSION: This particular gene modification results in changes in activity of phosphomannomutase modification, which could lead to PMM2-CDG-Ia with an uncommon phenotype.
Subject(s)
Genetic Predisposition to Disease , Phosphotransferases (Phosphomutases)/genetics , Primary Ovarian Insufficiency/genetics , Adult , China , Consanguinity , Female , Humans , Mutation, Missense/genetics , Pedigree , Phenotype , Primary Ovarian Insufficiency/physiopathology , SiblingsABSTRACT
Glioblastoma multiforme (GBM) is characterized by highly invasive growth, which leads to extensive infiltration and makes complete tumor excision difficult. Since cytoskeleton proteins are related to leading processes and cell motility, and through analysis of public GBM databases, we determined that an actin-interacting protein, zyxin (ZYX), may involved in GBM invasion. Our own glioma cohort as well as the cancer genome atlas (TCGA), Rembrandt, and Gravendeel databases consistently showed that increased ZYX expression was related to tumor progression and poor prognosis of glioma patients. In vitro and in vivo experiments further confirmed the oncogenic roles of ZYX and demonstrated the role of ZYX in GBM invasive growth. Moreover, RNA-seq and mass-spectrum data from GBM cells with or without ZYX revealed that stathmin 1 (STMN1) was a potential target of ZYX. Subsequently, we found that both mRNA and protein levels of STMN1 were positively regulated by ZYX. Functionally, STMN1 not only promoted invasion of GBM cells but also rescued the invasion repression caused by ZYX loss. Taken together, our results indicate that high ZYX expression was associated with worse prognosis and highlighted that the ZYX-STMN1 axis might be a potential therapeutic target for GBM.
Subject(s)
Brain Neoplasms , Glioblastoma , Neoplasm Invasiveness/pathology , Zyxin , Animals , Biomarkers, Tumor , Brain Neoplasms/diagnosis , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Brain Neoplasms/mortality , Cell Line, Tumor , Cell Movement/genetics , Gene Knockdown Techniques , Glioblastoma/diagnosis , Glioblastoma/genetics , Glioblastoma/metabolism , Glioblastoma/mortality , Humans , Mice , Mice, Inbred NOD , Prognosis , Stathmin/analysis , Stathmin/genetics , Stathmin/metabolism , Zyxin/analysis , Zyxin/genetics , Zyxin/metabolismABSTRACT
The special ecological environment of the Arctic has brought about a large number of salt-tolerant and psychrotolerant microorganisms. We isolated two culturable bacterial strains of the genus Mesonia; one from the Arctic ocean, Mesonia algae K4-1, and one from the tropical sea, Mesonia sp. HuA40. Our genome analysis and phenotypic experiments indicated that Mesonia algae K4-1 is a moderately halophilic and psychrophilic bacterium. Mesonia algae K4-1 can tolerate 3-14% NaCl and grow at a wide range of temperatures from 4 to 50°C. Mesonia sp. HuA40 is a mesophilic bacterium that can only grow with 3-9% NaCl. In addition, the salt adaptation strategy of Mesonia algae K4-1 accumulates organic osmolytes in the cell. RNA helicases, glutathione and organic compatible solutes may play important roles in maintaining the metabolism and physiological function of Mesonia algae K4-1 under cold stress. Moreover, the ability of Mesonia algae K4-1 to adapt to an oligotrophic marine environment is likely due to the synthesis of a large number of extracellular polysaccharides and the secretion of various families of extracellular proteases. This study systematically analyzed the relationship between genomic differentiation and environmental factors of the Mesonia genus and revealed the possible adaptation mechanism of Mesonia algae K4-1 in the extreme Arctic marine environment at the genomic level.
ABSTRACT
Soil-borne fungal pathogens that cause crop disease are major threats to agriculture worldwide. Here, we identified a secretory polysaccharide deacetylase (PDA1) from the soil-borne fungus Verticillium dahliae, the most notorious plant pathogen of the Verticillium genus, that facilitates virulence through direct deacetylation of chitin oligomers whose N-acetyl group contributes to host lysine motif (LysM)-containing receptor perception for ligand-triggered immunity. Polysaccharide deacetylases are widely present in fungi, bacteria, insects and marine invertebrates and have been reported to possess diverse functions in developmental processes rather than virulence. A phylogenetics analysis of more than 5,000 fungal proteins with conserved polysaccharide deacetylase domains showed that the V. dahliae PDA1-containing subtree includes a large number of proteins from the Verticillium genus as well as the Fusarium genus, another group of characterized soil-borne fungal pathogens, suggesting that soil-borne fungal pathogens have adopted chitin deacetylation as a major virulence strategy. We showed that a Fusarium PDA1 is required for virulence in cotton plants. This study reveals a substantial virulence function role of polysaccharide deacetylases in pathogenic fungi and demonstrates a subtle mechanism whereby deacetylation of chitin oligomers converts them to ligand-inactive chitosan, representing a common strategy of preventing chitin-triggered host immunity by soil-borne fungal pathogens.
Subject(s)
Amidohydrolases/metabolism , Chitin/metabolism , Gossypium/microbiology , Plant Diseases/microbiology , Soil Microbiology , Verticillium/pathogenicity , Acetylation , Amidohydrolases/genetics , Fusarium/enzymology , Fusarium/pathogenicity , Gossypium/metabolism , Solanum lycopersicum/metabolism , Verticillium/enzymology , VirulenceABSTRACT
The study reported on the isolation of a metalloprotease named EH2 from Pseudoalteromonas sp. H2. EH2 maintained more than 80% activity over a wide pH range of 5-10, and the stability was also nearly independent of pH. Over 65% activity was detected at a wide temperature range of 20-70 °C. The high stability of the protease in the presence of different surfactants and oxidizing agents was also observed. Moreover, we also investigated the antioxidant activities of the hydrolysates generated from porcine and salmon skin collagen by EH2. The results showed that salmon skin collagen hydrolysates demonstrated higher DPPH (1,1-diphenyl-2-picrylhydrazyl) (42.88% ± 1.85) and hydroxyl radical (61.83% ± 3.05) scavenging activity than porcine skin collagen. For oxygen radical absorbance capacity, the hydrolysates from porcine skin collagen had higher efficiency (7.72 ± 0.13 µmol·TE/µmol). Even 1 nM mixed peptides could effectively reduce the levels of intracellular reactive oxygen species. The two types of substrates exerted the best antioxidant activity when hydrolyzed for 3 h. The hydrolysis time and type of substrate exerted important effects on the antioxidant properties of hydrolysates. The hydrolyzed peptides from meat collagens by proteases have good antioxidant activity, which may have implications for the potential application of marine proteases in the biocatalysis industry.