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1.
New Phytol ; 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32155671

RESUMO

Soil fungi represent a major component of belowground biodiversity that determine the succession and recovery of forests after disturbance. However, their successional trajectories and driving mechanisms following wildfire remain unclear. We examined fungal biomass, richness, composition and enzymes across three soil horizons (Oe, A1 and A2) along a near-complete fire chronosequence (1yr, 2yr, 8yr, 14yr, 30yr, 49yr and ~260yr) in cold-temperate forests of the Greater Khingan Mountains, China. The importance of soil properties, spatial distance and tree composition were also tested. Ectomycorrhizal fungal richness and ß-glucosidase activity were strongly reduced by burning and significantly increased with time-since-fire in the Oe horizon but not in the mineral horizons. Time-since-fire and soil C/N ratio were the primary drivers of fungal composition in the Oe and A1/A2 horizons, respectively. Ectomycorrhizal fungal composition was remarkably sensitive to fire history in the Oe horizon, while saprotroph community was strongly affected by time-since-fire in the deeper soil horizon and this effect emerged eighteen years after fire in the A2 horizon. Our study demonstrates pronounced horizon-dependent successional trajectories following wildfire and indicates interactive effects of time-since-fire, soil stoichiometry and spatial distance in the reassembly of belowground fungal communities in a cold and fire-prone region.

2.
Dig Dis Sci ; 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897898

RESUMO

BACKGROUND: Emerged as important regulators in cancer progression, circular RNAs have been tested to participate in diverse biological processes. Former studies have suggested that circular RNA_LARP4 (circLARP4) exerts indispensable function on the development of different cancers such as gastric cancer and ovarian cancer. Nonetheless, the specific role of circLARP4 has not been discovered in ESCC. AIMS: The aim of this study is to explore the biological function and regulatory mechanism of circLARP4 in ESCC. METHODS: CircLARP4, miR-1323, and PTEN expression levels were quantified by RT-qPCR. CCK-8, EdU, caspase-3 activity, wound healing, transwell, and western blot assays were chosen to assess ESCC cell growth. Luciferase reporter, RIP, and RNA pull-down assays were performed to examine the interaction between miR-1323 and circLARP4 (or PTEN). RESULTS: CircLARP4 expression was observably downregulated in ESCC cell lines, and overexpressed circLARP4 restrained cell proliferation and migration whereas boosted cell apoptosis in ESCC. Molecular mechanism experiments revealed that circLARP4 could act as a sponge for miR-1323 and negatively modulated miR-1323 expression in ESCC. Interestingly, the repression of miR-1323 was correlated with inhibitive cell proliferation, migration, and promotive apoptosis. Besides, miR-1323 bound with PTEN, and PTEN expression was negatively regulated by miR-1323 whereas positively regulated by circLARP4 in ESCC. Moreover, rescue assays testified that miR-1323 overexpression or PTEN deficiency could countervail the function of circLARP4 overexpression on ESCC progression. More importantly, circLARP4 played an inhibitory role in PI3K/AKT pathway. CONCLUSIONS: CircLARP4 sponges miR-1323 and hampers tumorigenesis of ESCC through modulating PTEN/PI3K/AKT pathway.

3.
J Cell Physiol ; 235(4): 3657-3668, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31583713

RESUMO

Pancreatic ductal adenocarcinoma (PDA) responds poorly to treatment. Efforts have been exerted to prolong the survival time of PDA, but the 5-year survival rates remain disappointing. Understanding the molecular mechanisms of PDA development is significant. MEK/ERK pathway signaling has been proven to be important in PDA. lncRNA-mRNA networks have become a vital part of molecular mechanisms in the MEK/ERK pathway. Herein, weighted gene coexpression network analysis was used to investigate the coexpressed lncRNA-mRNA networks in the MEK/ERK pathway based on GSE45765. Differently expressed long noncoding RNA (lncRNA) and messenger RNA (mRNA) were found and 10 modules were identified based on coexpression profiles. Gene ontology and Kyoto Encyclopedia of Genes and Genomes were then performed to analyze the coexpressed lncRNA and mRNA in different modules. PDA cells and tissues were used to validate the analysis results. Finally, we found that NONHSAT185150.1 and B4GALT6 were negatively correlated with MEK1/2. By analyzing GSE45765, the genome-wide profiles of lncRNA-mRNA network after MEK1/2 was established, which might aid the development of drug-targeting MEK1/2 and the investigation of diagnostic markers.

4.
Int J Biol Macromol ; 143: 76-84, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31816381

RESUMO

Acidic heteropolysaccharide (LP) from Lycium barbarum L. leaves has compact globular structure which wrapped abundant endogenous minerals inside by ionic interactions with uronic acid. This study investigated the efficacy of chemical degradation of LP on the bioaccessibility and transport of endogenous minerals in simulated gastrointestinal fluids. Results showed that the degradation using vitamin C and hydrogen peroxide mildly decreased LP molecular weight from 162.0 kDa to 94.3 kDa, and the structure of degraded LP (LPD) was converted to loose coil. After the simulated intestinal digestion, the accessibility of Ca, Fe, Zn, and Mg in LPD increased by119%, 52%, 103% and 112.5% compared with the intact LP, respectively, and in particular, the uptake rate increased by 15.8%, 8.1%, 23.4% and 21.6% for Ca, Fe, Zn, and Mg, respectively. These results demonstrated that the chemical degradation is a helpful strategy to improve the uptake of endogenous minerals wrapped in polysaccharide.

5.
Int J Biol Macromol ; 143: 602-609, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31837362

RESUMO

We report the inclusion of cyclolipopeptides (CL) from Bacillus subtilis in the production of an easily removed alginate coating for the preservation of vulnerable berries. The sodium alginate-CL (SA-CL) coating films exhibited potent antifungal and freshness-maintaining properties during the storage of blueberries, the 3% CL-added film decreased total fungal count to 2.5 × 103 cfu/g at the end of the storage. The SA-CL films had poor mechanical properties (i.e., tensile strength and elongation at break), low water vapor permeability and high water solubility. The addition of CL (3%) decreased the tensile strength and elongation at break of the SA-CL film to 0.37 mPa and 2.57%, respectively, and increased the water solubility to 28.92%. But the water vapor permeability of the 3% film was lowered to 398.10 g/m2/day. These results implied the film was suitable for the coating of vulnerable berries. Further research revealed that ionic and hydrogen bonding interactions between CL and alginate stabilized the network of the coating film while the fatty acid moiety weakened the strength and crystallinity and restricted the water transfer of the coating film. Our findings provide an effective route to an easily washed alginate coating film through inclusion of amphiphilic antifungal substances.

6.
Vet Microbiol ; 234: 92-100, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31213278

RESUMO

Streptococcus suis (SS) is a major pathogen in the swine industry, and also an important zoonotic agent for humans. The novel SS cell surface protein, AtlASS, comprising the special GW module and N-acetylmuramidases domain, was designated as a putative autolysin. Indeed, the atlASS deletion mutant almost completely lost its activity in Triton X-100 induced bacterial autolysis, while the wild-type and CΔatlASS strains showed significant decrease, to less than 20% of the initial OD600 values. Unexpectedly, both immunofluorescence and immunogold electron microscopy confirmed that AtlASS is mainly located in the cell division septum, suggesting autolytic activity in peptidoglycan hydrolysis may be required for cell separation, thus modulating and truncating bacterial chain length. The biofilm capacity of the AtlASS mutation was reduced ˜ 40%, as compared to the wild-type strain. The ΔatlASS strain also attenuated bacterial adherence in human brain microvessel endothelial cells (HBMECs). Furthermore, we confirmed that AtlASS has fibrinogen/fibronectin binding capacities. In mouse infection model, the AtlASS inactivation also significantly attenuated bacterial virulence and proliferation in vivo. In conclusion, these results indicate that AtlASS autolysin modulates bacterial chain length, and contributes to the full virulence of SS during infection.


Assuntos
Divisão Celular , N-Acetil-Muramil-L-Alanina Amidase/metabolismo , Streptococcus suis/química , Streptococcus suis/patogenicidade , Animais , Autólise , Biofilmes/crescimento & desenvolvimento , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Mutação , N-Acetil-Muramil-L-Alanina Amidase/genética , Organismos Livres de Patógenos Específicos , Virulência
7.
Ecol Evol ; 9(11): 6678-6692, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31236252

RESUMO

The dramatic climate fluctuations of the late Quaternary have influenced the diversity and composition of macroorganism communities, but how they structure belowground microbial communities is less well known. Fungi constitute an important component of soil microorganism communities. They play an important role in biodiversity maintenance, community assembly, and ecosystem functioning, and differ from many macroorganisms in many traits. Here, we examined soil fungal communities in Chinese temperate, subtropical, and tropic forests using Illumina MiSeq sequencing of the fungal ITS1 region. The relative effect of late Quaternary climate change and contemporary environment (plant, soil, current climate, and geographic distance) on the soil fungal community was analyzed. The richness of the total fungal community, along with saprotrophic, ectomycorrhizal (EM), and pathogenic fungal communities, was influenced primarily by the contemporary environment (plant and/or soil) but not by late Quaternary climate change. Late Quaternary climate change acted in concert with the contemporary environment to shape total, saprotrophic, EM, and pathogenic fungal community compositions and with a stronger effect in temperate forest than in tropic-subtropical forest ecosystems. Some contemporary environmental factors influencing total, saprotrophic, EM, and pathogenic fungal communities in temperate and tropic-subtropical forests were different. We demonstrate that late Quaternary climate change can help to explain current soil fungal community composition and argue that climatic legacies can help to predict soil fungal responses to climate change.

8.
Carbohydr Polym ; 216: 149-156, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31047051

RESUMO

A novel porous ß-cyclodextrin/pillar[5]arene copolymer was prepared using tetrafluoroterephthalonitrile as cross-linker for rapid removal of variety of organic pollutants. The copolymer was characterized by water contact angle, scanning electron microscope, FT-IR spectrum, solid-state 13C NMR spectrum, thermo-gravimetric analysis, nitrogen adsorption-desorption isotherms, and elemental analysis. Results showed that the co-polymer had good water immersibility, co-existing micro-/meso-pores, and a large specific surface area (BET) of 479 m2/g. The copolymer presented high adsorption capacity with the maximum adsorption capacity of 258 mg/g for bisphenol A and good reusability and reproducibility. It also showed fast binding kinetics with the apparent second-order rate constants of 0.109-0.179 g/mg·min and simultaneously rapid removal ability with removal efficiencies of 74-90% within 30 s for variety of organic pollutants. The new copolymer can be potentially used as adsorbent for rapidly removing a wide range of organic pollutants in wastewater.


Assuntos
Calixarenos/química , Polímeros/química , Poluentes Químicos da Água/química , Água/química , beta-Ciclodextrinas/química , Adsorção , Calixarenos/síntese química , Polímeros/síntese química , Porosidade , Reprodutibilidade dos Testes , Purificação da Água/métodos , beta-Ciclodextrinas/síntese química
9.
FEMS Microbiol Ecol ; 95(4)2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30889238

RESUMO

Environmental filtering and dispersal limitation are two of the primary drivers of community assembly in ecosystems, but their effects on ectomycorrhizal (EM) fungal communities associated with wide ranges of Betulaceae taxa at a large scale are poorly documented. In this study, we examined EM fungal communities associated with 23 species from four genera (Alnus, Betula, Carpinus and Corylus) of Betulaceae in Chinese secondary forest ecosystems, using Illumina MiSeq sequencing of the ITS2 region. Effects of host plant phylogeny, soil, climate and geographic distance on EM fungal community were explored. In total, we distinguished 1738 EM fungal operational taxonomic units (OTUs) at a 97% sequence similarity level. The EM fungal communities of Alnus had significantly lower OTU richness than those associated with the other three plant genera. The EM fungal OTU richness was significantly affected by geographic distance, host plant phylogeny, soil and climate. The EM fungal community composition was significantly influenced by host plant phylogeny (12.1% of variation explained in EM fungal community), geographic distance (7.7%), soil (4.6%) and climate (1.1%). This finding highlights that environmental filtering linked to host plant phylogeny and dispersal limitation strongly influence EM fungal communities associated with Betulaceae plants in Chinese secondary forest ecosystems.

10.
Front Microbiol ; 9: 2409, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30364168

RESUMO

Environmental filtering (niche process) and dispersal limitation (neutral process) are two of the primary forces driving community assembly in ecosystems, but how these processes affect the Fagaceae-associated ectomycorrhizal (EM) fungal community at regional scales is so far poorly documented. We examined the EM fungal communities of 61 plant species in six genera belonging to the Fagaceae distributed across Chinese forest ecosystems (geographic distance up to ∼3,757 km) using Illumina Miseq sequencing of ITS2 sequences. The relative effects of environmental filtering (e.g., host plant phylogeny, soil and climate) and dispersal limitation (e.g., spatial distance) on the EM fungal community were distinguished using multiple models. In total, 2,706 operational taxonomic units (OTUs) of EM fungi, corresponding to 54 fungal lineages, were recovered at a 97% sequence similarity level. The EM fungal OTU richness was significantly affected by soil pH and nutrients and by host phylogeny. The EM fungal community composition was significantly influenced by combinations of host phylogeny, spatial distance, soil and climate. Furthermore, host phylogeny had the greatest effect on EM fungal community. The study suggests that the assembly of the EM fungal community is governed by both environmental filtering and dispersal limitation, with host effect being the most important determinant at the regional scale.

11.
Appl Environ Microbiol ; 84(18)2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-30030221

RESUMO

Streptococcus suis is an important Gram-positive pathogen in the swine industry and is an emerging zoonotic pathogen for humans. In our previous work, we found a virulent S. suis strain, CZ130302, belonging to a novel serotype, Chz, to be associated with acute meningitis in piglets. However, its underlying mechanisms of pathogenesis remain poorly understood. In this study, we sequenced and analyzed the complete genomes of three Chz serotype strains, including strain CZ130302 and two avirulent strains, HN136 and AH681. By genome comparison, we found two putative genomic islands (GIs) uniquely encoded in strain CZ130302 and designated them 50K GI and 58K GI. In mouse infection model, the deletion of 50K and 58K GIs caused 270-fold and 3-fold attenuation of virulence, respectively. Notably, we identified a complete SecY2/A2 system, coupled with its secretory protein SssP1 encoded in the 50K GI, which contributed to the pathogenicity of strain CZ130302. Immunogold electron microscopy and immunofluorescence analyses indicated that SssP1 could form fimbria-like structures that extend outward from the bacterial cell surface. The sssP1 mutation also attenuated bacterial adherence in human laryngeal epithelial (HEp-2) cells and human brain microvessel endothelial cells (HBMECs) compared with the wild type. Furthermore, we showed that two analogous Ig-like subdomains of SssP1 have sialic acid binding capacities. In conclusion, our results revealed that the 50K GI and the inside SecY2/A2 system gene cluster are related to the virulence of strain CZ130302, and we clarified a new S. suis pathogenesis mechanism mediated by the secretion protein SssP1.IMPORTANCE Streptococcus suis is an important zoonotic pathogen. Here, we managed to identify key factors to clarify the virulence of S. suis strain CZ130302 from a novel serotype, Chz. Notably, it was shown that a fimbria-like structure was significantly connected to the pathogenicity of the CZ130302 strain by comparative genomics analysis and animal infection assays. The mechanisms of how the CZ130302 strain constructs these fimbria-like structures in the cell surface by genes encoding and production transport were subsequently elucidated. Biosynthesis of the fimbria-like structure was achieved by the production of SssP1 glycoproteins, and its construction was dependent on the SecA2/Y2 secretion system. This study identified a visible fimbria-like protein, SssP1, participating in adhesion to host cells and contributing to the virulence in S. suis These findings will promote a better understanding of the pathogenesis of S. suis.


Assuntos
Proteínas de Bactérias/genética , Fímbrias Bacterianas/genética , Genoma Bacteriano/fisiologia , Streptococcus suis/genética , Streptococcus suis/patogenicidade , Proteínas de Bactérias/metabolismo , Sorogrupo , Infecções Estreptocócicas/microbiologia , Streptococcus suis/metabolismo , Virulência/genética
12.
Talanta ; 187: 207-215, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29853037

RESUMO

A new microporous ß-cyclodextrin polymer (MP-CDP) was prepared for the simultaneous solid-phase extraction (SPE) of bisphenol F (BPF), bisphenol A (BPA) and bisphenol AF (BPAF). The MP-CDP was characterized by Fourier transform infrared spectroscopy, solid-phase 13C nuclear magnetic resonance, thermo-gravimetric analysis, scanning electron microscopy, and nitrogen adsorption and desorption analysis. Results indicated that the MP-CDP had micron-level particle size, microporous structure, a high BET surface area, and a high product yield. Adsorption tests showed that the MP-CDP sorbent had high adsorption ability and fast binding kinetics for bisphenols. Moreover, the MP-CDP presented high extraction efficiencies, high enrichment factor, good reusability and good batch-to-batch reproducibility for SPE of bisphenols. Based on the MP-CDP sorbent, a SPE-HPLC-UV method was developed and successfully applied to simultaneously detect three bisphenols in water samples and orange juice with the recoveries of 95.7-106.3% (RSD = 2.0-5.2%) for BPF, 92.9-107.0% (RSD = 1.5-5.1%) for BPA, and 96.0-103.5% (RSD = 1.7-5.0%) for BPAF, respectively. The limit of detection (S/N = 3) and the limit of quantification (S/N = 10) for all bisphenols in these samples were 0.15 ng/mL and 0.5 ng/mL, respectively. The new MP-CDP can be potentially utilized as a good sorbent for simultaneous SPE of trace bisphenols in environmental water samples and beverages.


Assuntos
Sucos de Frutas e Vegetais/análise , Fenóis/análise , Polímeros/química , Extração em Fase Sólida , Poluentes Químicos da Água/química , beta-Ciclodextrinas/química , Adsorção , Citrus sinensis/química , Tamanho da Partícula , Porosidade , Propriedades de Superfície
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