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28 result(s) for "Sun, Bing-Da"
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Bioactive secondary metabolites from endophytic strains of Neocamarosporium betae collected from desert plants
Endophytic fungi from desert plants belong to a unique microbial community that has been scarcely investigated chemically and could be a new resource for bioactive natural products. In this study, 13 secondary metabolites ( 1–13 ) with diverse carbon skeletons, including a novel polyketide (1) with a unique 5,6-dihydro-4 H ,7 H -2,6-methanopyrano[4,3- d ][1,3]dioxocin-7-one ring system and three undescribed polyketides ( 2 , 7 , and 11 ), were obtained from the endophytic fungus Neocamarosporium betae isolated from two desert plant species. Different approaches, including HR-ESI-MS, UV spectroscopy, IR spectroscopy, NMR, and CD, were used to determine the planar and absolute configurations of the compounds. The possible biosynthetic pathways were proposed based on the structural characteristics of compounds 1–13 . Compounds 1 , 3 , 4 , and 9 exhibited strong cytotoxicity toward HepG2 cells compared with the positive control. Several metabolites ( 2 , 4–5 , 7–9 , and 11–13 ) were phytotoxic to foxtail leaves. The results support the hypothesis that endophytic fungi from special environments, such as desert areas, produce novel bioactive secondary metabolites.
Spiciferone analogs from an endophytic fungus Phoma betae collected from desert plants in West China
Endophytic fungi from desert, arid, and grassland areas are an ecologically important but unique group with poor chemical investigation. During our ongoing study to mine bioactive secondary metabolites from unique fungal environments, a new shunt product spiciferone F (1) including two new analogs spiciferones G (2) and H (3) together with four known ones spiciferone A (4), spiciferol A (5), 6, and 7 were isolated from endophytic fungus Phoma betae inhabiting in plant Kalidium foliatum (Pall.) Moq from Ningxia Province of West China. The planar, relative, and absolute configurations of these new compounds were elucidated by nuclear magnetic resonance, high-resolution electrospray ionization mass spectrometry, and electronic circular dichroism experiments. According to the shunt products, intermediates and analogs isolated from this endophytic fungus, the possible biosynthetic pathway of spiciferones was reconstructed. Compounds 1–7 were evaluated cytotoxic activities against three cancer cell lines HCT 116, HeLa, and MCF7, and only did 1 display strong biological effect against MCF7 with a half-maximal inhibitory concentration value at 7.73 ± 0.11 μM compared with the cis-platinum (14.32 ± 1.01 μM).
Phylogenetic assessment and taxonomic revision of Scytalidium (Helotiales, Leotiomycetes)
Members of Scytalidium are primarily saprotrophic and are known for their ability to colonize a variety of substrates, including soil, decaying plant material, and wood. During an investigation of soil microfungi in Capsicum annuum cultivation areas of China, seven Scytalidium isolates were obtained from soil samples collected in Guizhou. In this study, we revised the genus Scytalidium by combining morphological characteristics and phylogenetic analyses based on concatenated ITS–LSU sequences. The results showed that Scytalidium sensu stricto comprises 16 species, including the type species S. lignicola and four novel species proposed in this study ( S. chlamydosporum , S. guizhouense , S. rodionovae , and S. tongrenense ). Ten species were excluded, and six species were treated as uncertain due to the lack of available molecular sequences. This study revised the genus Scytalidium , expanded its species diversity and geographical distribution, and lays the foundation for future taxonomic research on this genus.
Identification of Ochratoxin A Producing Fungi Associated with Fresh and Dry Liquorice
The presence of fungi on liquorice could contaminate the crop and result in elevated levels of mycotoxin. In this study, the mycobiota associated with fresh and dry liquorice was investigated in 3 producing regions of China. Potential toxigenic fungi were tested for ochratoxin A (OTA) and aflatoxin B1 (AFB1) production using liquid chromatography/mass spectrometry/mass spectrometry. Based on a polyphasic approach using morphological characters, β-tubulin and RNA polymerase II second largest subunit gene phylogeny, a total of 9 genera consisting of 22 fungal species were identified, including two new Penicillium species (Penicillium glycyrrhizacola sp. nov. and Penicillium xingjiangense sp. nov.). The similarity of fungal communities associated with fresh and dry liquorice was low. Nineteen species belonging to 8 genera were detected from fresh liquorice with populations affiliated with P. glycyrrhizacola, P. chrysogenum and Aspergillus insuetus comprising the majority (78.74%, 33.33% and 47.06% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. In contrast, ten species belonging to 4 genera were detected from dry liquorice with populations affiliated with P. chrysogenum, P. crustosum and Aspergillus terreus comprising the majority (64.00%, 52.38% and 90.91% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. Subsequent LC/MS/MS analysis indicated that 5 fungal species were able to synthesize OTA in vitro including P. chrysogenum, P. glycyrrhizacola, P. polonicum, Aspergillus ochraceus and A. westerdijkiae, the OTA concentration varied from 12.99 to 39.03 µg/kg. AFB1 was absent in all tested strains. These results demonstrate the presence of OTA producing fungi on fresh liquorice and suggest that these fungi could survive on dry liquorice after traditional sun drying. Penicillium chrysogenum derived from surrounding environments is likely to be a stable contributor to high OTA level in liquorice. The harvesting and processing procedure needs to be monitored in order to keep liquorice free of toxigenic fungi.
UPLC-QTOFMS-based metabolomic analysis of the serum of hypoxic preconditioning mice
Hypoxic preconditioning (HPC) is well-known to exert a protective effect against hypoxic injury; however, the underlying molecular mechanism remains unclear. The present study utilized a serum metabolomics approach to detect the alterations associated with HPC. In the present study, an animal model of HPC was established by exposing adult BALB/c mice to acute repetitive hypoxia four times. The serum samples were collected by orbital blood sampling. Metabolite profiling was performed using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS), in conjunction with univariate and multivariate statistical analyses. The results of the present study confirmed that the HPC mouse model was established and refined, suggesting significant differences between the control and HPC groups at the molecular levels. HPC caused significant metabolic alterations, as represented by the significant upregulation of valine, methionine, tyrosine, isoleucine, phenylalanine, lysophosphatidylcholine (LysoPC; 16:1), LysoPC (22:6), linoelaidylcarnitine, palmitoylcarnitine, octadecenoylcarnitine, taurine, arachidonic acid, linoleic acid, oleic acid and palmitic acid, and the downregulation of acetylcarnitine, malate, citrate and succinate. Using MetaboAnalyst 3.0, a number of key metabolic pathways were observed to be acutely perturbed, including valine, leucine and isoleucine biosynthesis, in addition to taurine, hypotaurine, phenylalanine, linoleic acid and arachidonic acid metabolism. The results of the present study provided novel insights into the mechanisms involved in the acclimatization of organisms to hypoxia, and demonstrated the protective mechanism of HPC.
Metabolite Modulation in Human Plasma in the Early Phase of Acclimatization to Hypobaric Hypoxia
The exposure of healthy subjects to high altitude represents a model to explore the pathophysiology of diseases related to tissue hypoxia. We explored a plasma metabolomics approach to detect alterations induced by the exposure of subjects to high altitude. Plasma samples were collected from 60 subjects both on plain and at high altitude (5300 m). Metabolite profiling was performed by gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS) in conjunction with univariate and multivariate statistical analyses. ELISA assays were further employed to measure the levels of several relevant enzymes together with perturbed metabolic pathways. The results showed that hypobaric hypoxia caused significant and comprehensive metabolic changes, as represented by significant changes of 44 metabolites and 4 relevant enzymes. Using MetaboAnalyst 3.0, it was found that several key metabolic pathways were acutely perturbed. In addition, 5 differentially expressed metabolites in pre-exposure samples from the acute mountain sickness-susceptible (AMS-S) group compared with those from the AMS-resistant (AMS-R) group are identified, which warrant further validation as potential predictive biomarkers for AMS-S individuals. These results provide new insights for further understanding the pathophysiological mechanism of early acclimatization to hypobaric hypoxia and other diseases correlated to tissue hypoxia.
A new genus and two new species of Wiesneriomycetaceae (Tubeufiales) from China revealed by molecular phylogeny and taxonomy
While investigating culturable mycobiota in epiphytic soils found in urban tree holes from Guizhou Province, China, a new genus along with two new species of the family Wiesneriomycetaceae were discovered based on a combination of morphological characteristics, molecular evidence, and physiological features. Phylogenetic analyses of SSU, ITS, LSU, and tef1 sequences indicate that our new collections form a distinct clade; thus, Chlamydosporoides gen. nov. is proposed. This genus is distinguished from other genera in Wiesneriomycetaceae by the absence of acropetal conidial chains, setae, synnemata, sporodochia, or stromata. We describe and illustrate the new genus Chlamydosporoides and the new species ( C. guizhouensis sp. nov. and C. sinensis sp. nov. ) herein, and we discuss their phenotypic and genotypic differences from allied genera.
Elevated pentose phosphate pathway is involved in the recovery of hypoxia-induced erythrocytosis
As a typical model of hypoxia-induced excessive erythrocytosis, high altitude polycythemia (HAPC) results in microcirculation disturbance, aggravates tissue hypoxia and results in a severe clinical outcome, without any effective intervention methods except for returning to an oxygen-rich environment. The present study aimed to explore potential therapeutic targets which may participate in the recovery of HAPC by studying the mechanisms of reducing the hemoglobin (HB) concentration during re-oxygenation. A total of 14 and 13 subjects were recruited over a 5,300 m distance and 5,170 m area. The patients were classified into HAPC or control groups based on their HB value. Plasma samples were collected on the day when they finished their stay in plateau for a year, and on the 180th day following their reaching in plain. Metabolic profiling was conducted by UPLC-QTOF/MS. MetaboAnalyst platform was performed to explore the most perturbed metabolic pathways. A panel of differential metabolites were obtained in the recovery phase of HAPC and control groups. The present study identified the uniquely upregulated pentose phosphate pathway in HAPC subjects, along with a significantly decreased HB level. The findings were verified via a direct comparison between HAPC and control subjects at a high altitude. An increased pentose phosphate pathway was identified in control groups compared with HAPC subjects. An elevated pentose phosphate pathway may therefore participate in the recovery of HAPC, whereas a downregulated pentose phosphate pathway may contribute to hypoxia-induced erythrocytosis. The results of the present study provide potential therapeutic strategies and novel insights into the pathogenesis of hypoxia-induced polycythemia.
Identification of Ochratoxin A Producing Fungi Associated with Fresh and Dry Liquorice: e78285
The presence of fungi on liquorice could contaminate the crop and result in elevated levels of mycotoxin. In this study, the mycobiota associated with fresh and dry liquorice was investigated in 3 producing regions of China. Potential toxigenic fungi were tested for ochratoxin A (OTA) and aflatoxin B1 (AFB1) production using liquid chromatography/mass spectrometry/mass spectrometry. Based on a polyphasic approach using morphological characters, beta -tubulin and RNA polymerase II second largest subunit gene phylogeny, a total of 9 genera consisting of 22 fungal species were identified, including two new Penicillium species (Penicillium glycyrrhizacola sp. nov. and Penicillium xingjiangense sp. nov.). The similarity of fungal communities associated with fresh and dry liquorice was low. Nineteen species belonging to 8 genera were detected from fresh liquorice with populations affiliated with P. glycyrrhizacola, P. chrysogenum and Aspergillus insuetus comprising the majority (78.74%, 33.33% and 47.06% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. In contrast, ten species belonging to 4 genera were detected from dry liquorice with populations affiliated with P. chrysogenum, P. crustosum and Aspergillus terreus comprising the majority (64.00%, 52.38% and 90.91% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. Subsequent LC/MS/MS analysis indicated that 5 fungal species were able to synthesize OTA in vitro including P. chrysogenum, P. glycyrrhizacola, P. polonicum, Aspergillus ochraceus and A. westerdijkiae, the OTA concentration varied from 12.99 to 39.03 mu g/kg. AFB1 was absent in all tested strains. These results demonstrate the presence of OTA producing fungi on fresh liquorice and suggest that these fungi could survive on dry liquorice after traditional sun drying. Penicillium chrysogenum derived from surrounding environments is likely to be a stable contributor to high OTA level in liquorice. The harvesting and processing procedure needs to be monitored in order to keep liquorice free of toxigenic fungi.
Plasma-induced, nitrogen-doped graphene-based aerogels for high-performance supercapacitors
Commonly used energy storage devices include stacked layers of active materials on two-dimensional sheets, and the limited specific surface area restricts the further development of energy storage. Three-dimensional (3D) structures with high specific surface areas would improve device performance. Herein, we present a novel procedure to fabricate macroscopic, high-quality, nitrogen-doped, 3D graphene/nanoparticle aerogels. The procedure includes vacuum filtration, freeze-drying, and plasma treatment, which can be further expanded for large-scale production of nitrogen-doped, graphene-based aerogels. The behavior of the supercapacitor is investigated using a typical nitrogen-doped graphene/Fe 3 O 4 nanoparticle 3D structure (NG/Fe 3 O 4 ). Compared with 3D graphene/Fe 3 O 4 structures prepared by the traditional hydrothermal method, the NG/Fe 3 O 4 supercapacitor prepared by the present method has a 153% improvement in specific capacitance, and there is no obvious decrease in specific capacitance after 1000 cycles. The present work provides a new and facile method to produce large-scale, 3D, graphene-based materials with high specific capacitance for energy storage. Plasmas: simple method for producing energy storage materials A facile, scalable way involving plasma treatment has been used to fabricate three-dimensional graphene-based materials for energy storage. Three-dimensional porous graphene-based structures are highly desired for various applications including energy storage, but current fabrication methods are complex and use harmful chemicals. Now, Dabing Li at the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences in China and colleagues have come up with a simple procedure for producing aerogels consisting of nitrogen-doped three-dimensional graphene and iron oxide nanoparticles. The method involves vacuum filtration, freeze drying and plasma treatment, and has the advantages of being inexpensive and environmentally friendly. The researchers demonstrate its potential by producing a supercapacitor that exhibits improved porosity and a higher specific capacitance than aerogels prepared by conventional methods. Furthermore, its specific capacitance did not noticeably decrease after 1000 cycles.