Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudokno...Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudoknot)that have been demonstrated to be well conserved.However,it is still unclear whether each stem-loop subdomain,such as a single stem or loop,is also highly conserved.To clarify this issue in the present study,a set of 29 SVA cDNA clones were constructed by site-directed mutagenesis(SDM)on the IRES.The SDM-modified scenarios included:(1)stem-formed complementary sequences exchanging with each other;(2)loop transversion;(3)loop transition;and(4)point mutations.All cDNA clones were separately transfected into cells for rescuing viable viruses,whereas only four SVAs of interest could be recovered,and were genetically stable during 20 passages.One progeny grew significantly slower than the other three did.The dual-luciferase reporter assay showed that none of the SDM-modified IRESes significantly inhibited the IRES activity.Our previous study indicated that a single motif from any of the ten stem structures,if completely mutated,would cause the failure of virus recovery.Interestingly,our present study revealed three stem structures,whose individual complementary sequences could exchange with each other to rescue sequence-modifying SVAs.Moreover,one apical loop was demonstrated to have the ability to tolerate its own full-length transition,also having no impact on the recovery of sequence-modifying SVA.The present study suggested that not every stem-loop structure was strictly conserved in its conformation,while the full-length IRES itself was well conserved.This provides a new research direction on interaction between the IRES and many factors.展开更多
Beer is a fermented beverage prepared from water,malted barley,hops,and yeast that has been around for centuries.Alcoholic beverages alter the composition of the gut microbiota,which in turn causes oxidative stress br...Beer is a fermented beverage prepared from water,malted barley,hops,and yeast that has been around for centuries.Alcoholic beverages alter the composition of the gut microbiota,which in turn causes oxidative stress brought on by alcohol,increases intestinal permeability to luminal bacterial products.However,beer has been shown to contain several intriguing non-alcoholic chemicals.Recent research demonstrates that moderate beer drinking could have positive impacts on human health.Beer’s non-alcoholic ingredients have a significant impact on gut microbiota,and this type of diet is known to modulate gut microbiota,which has a variety of effects on the body,including effects on intestinal permeability,mucosal immune function,intestinal motility,antioxidant activity,and anti-inflammatory activity.Although the negative consequences of excessive alcohol intake are widely known,it is still debatable whether or not some non-alcoholic components,such as polyphenols and carbohydrates,have any positive benefits.In this review,we explain the primary benefits of moderate beer consumption on the gut microbiota,which are mostly attributable to non-alcoholic components such polyphenols.Despite any potential advantages of moderating consumption of alcoholic beverages,the lowest alcohol intake is the most secure.展开更多
The authors were contacted after publication to request a replacement of Fig.2M in the manuscript.Unfortunately,the authors inadvertently used an image of the model(Vehicle)group liver histopathology section that matc...The authors were contacted after publication to request a replacement of Fig.2M in the manuscript.Unfortunately,the authors inadvertently used an image of the model(Vehicle)group liver histopathology section that matches an image published in Fig.2D of Cell Reports(Volume 26,Issue 1,pages 222–235.e5).展开更多
The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosyn...The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosynthesis(MES)is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO_(2) into high-value products.The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system.Therefore,this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system.The topics covered include inward extracellular electron transfer pathways,cathode materials,applied cathode potentials,catholyte pH,and reactor configuration.In addition,this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO_(2) into high-value products via MES.展开更多
Fusobacterium nucleatum(F.nucleatum)is an early pathogenic colonizer in periodontitis,but the host response to infection with this pathogen remains unclear.In this study,we built an F.nucleatum infectious model with h...Fusobacterium nucleatum(F.nucleatum)is an early pathogenic colonizer in periodontitis,but the host response to infection with this pathogen remains unclear.In this study,we built an F.nucleatum infectious model with human periodontal ligament stem cells(PDLSCs)and showed that F.nucleatum could inhibit proliferation,and facilitate apoptosis,ferroptosis,and inflammatory cytokine production in a dose-dependent manner.The F.nucleatum adhesin Fad A acted as a proinflammatory virulence factor and increased the expression of interleukin(IL)-1β,IL-6 and IL-8.Further study showed that Fad A could bind with PEBP1 to activate the Raf1-MAPK and IKK-NF-κB signaling pathways.Time-course RNA-sequencing analyses showed the cascade of gene activation process in PDLSCs with increasing durations of F.nucleatum infection.NFκB1 and NFκB2 upregulated after 3 h of F.nucleatum-infection,and the inflammatory-related genes in the NF-κB signaling pathway were serially elevated with time.Using computational drug repositioning analysis,we predicted and validated that two potential drugs(piperlongumine and fisetin)could attenuate the negative effects of F.nucleatum-infection.Collectively,this study unveils the potential pathogenic mechanisms of F.nucleatum and the host inflammatory response at the early stage of F.nucleatum infection.展开更多
Many studies have revealed that gut microbes modulate host metabolism.In this study,we characterized the therapeutic effects of a novel gut commensal Luoshenia tenuis against host metabolic disorders.First,by in silic...Many studies have revealed that gut microbes modulate host metabolism.In this study,we characterized the therapeutic effects of a novel gut commensal Luoshenia tenuis against host metabolic disorders.First,by in silico analysis,we demonstrated that the L.tenuis was prevalent in the gut microbiomes of healthy humans but were depleted specifically in obesity cohorts.Further in vitro cultivation revealed that L.tenuis produced short chain fatty acids that were verified to modulate host metabolism and some other volatile metabolites to benefit hosts by anti-inflammation and anti-tumor.Second,gavage of the L.tenuis significantly decreased the body weight gain and food intake of high-fat diet-feeding C57BL/6J mice,which was in parallel with the changed expression level of genes related to satiety and feeding behavior.We then performed the gavage trial using diet induced obese mice,and it revealed that the administration of L.tenuis alleviated significantly the abnormal glucose and lipid metabolisms and reduced the inflammatory response.In summary,this study revealed a previously-unknown human gut commensal microbe that benefited host metabolism,and set the stage for the development of novel next-generation probiotic applicable for treatment of obesity and related metabolic disorders.展开更多
Microbial natural products and their derivatives have been developed as a considerable part of clinical drugs and agricultural chemicals.Marine microbial natural products exhibit diverse chemical structures and bioact...Microbial natural products and their derivatives have been developed as a considerable part of clinical drugs and agricultural chemicals.Marine microbial natural products exhibit diverse chemical structures and bioactivities with substantial potential for the development of novel pharmaceuticals.However,discovering compounds with new skeletons from marine microbes remains challenging.In recent decades,multiple approaches have been de-veloped to discover novel marine microbial natural products,among which heterologous expression has proven to be an effective method.Facilitated by large DNA cloning and comparative metabolomic technologies,a few novel bioactive natural products from marine microorganisms have been identified by the expression of their biosynthetic gene clusters(BGCs)in heterologous hosts.Heterologous expression is advantageous for character-izing gene functions and elucidating the biosynthetic mechanisms of natural products.This review provides an overview of recent progress in heterologous expression-guided discovery,biosynthetic mechanism elucidation,and yield optimization of natural products from marine microorganisms and discusses the future directions of the heterologous expression strategy in facilitating novel natural product exploitation.展开更多
The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing g...The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing glu-cose and (NH4)2HPO4, the strain could convert 137.0g of glucose into 52.4g of 2,3-butanediol and 8.4g of acetoin in shaking flasks. The diol yield amounted to 90% of its theoretical value and the productivity was 1—1.5g·L-1·h-1. In fed-batch fermentation, the yield and productivity of diol were further enhanced by maintaining the pH at 6.0. Up to 92.4g of 2,3-butanediol and 13.1g of acetoin per liter were obtained from 215.0g of glucose per liter. The diol yield reached 98% of its theoretical value and the productivity was up to 2.1g·L-1·h-1.展开更多
Two uridine auxotrophic mutants of Trichoderma reesei were isolated by resistance to 5-fluoroorotic acid after UV mutagenesis. One mutant, called M23, was complemented with the Aspergillus niger pyrG gene carried by p...Two uridine auxotrophic mutants of Trichoderma reesei were isolated by resistance to 5-fluoroorotic acid after UV mutagenesis. One mutant, called M23, was complemented with the Aspergillus niger pyrG gene carried by plasmid pAB4-1. A mutated pyrG gene of M23 was cloned and DNA sequencing analysis indicated that a cytosine was inserted into the 934―939 oligo dC position of the pyrG coding region, resulted in a frameshift mutation. Transformation efficiency was approximately 200―300 transformants per microgram of DNA with plasmid pAB4-1. Stable transformants were obtained by monosporic culture and showed to be prototroph after successive propagation. Vitreoscilla hemoglobin expression plasmid pUCVHb was cotransformed with plasmid pAB4-1 and attained a transformation efficiency of 71.8% or of 26.1% with pAN7-1. Southern blot analysis of the transformants demonstrated that plasmid pUCVHb was integrated into the chromosomal DNA. The experimental results demonstrated that the pyrG-based system was more efficient and timesaving than the conventional hygromycin B resistance-based transformation system.展开更多
The laccase-catalyzed conversion of bisphenol A （BPA） in aqueous solutions was studied in the absence and presence of nonionic surfactant Triton X-100. It was found that the addition of Triton X-100 into the reactio...The laccase-catalyzed conversion of bisphenol A （BPA） in aqueous solutions was studied in the absence and presence of nonionic surfactant Triton X-100. It was found that the addition of Triton X-100 into the reaction system increased the conversion of BPA, especially near the critical micelle concentration of Triton X-100. Also it was found that the stability of laccase was greatly improved in the presence of TritonX-100. Studies on the endogenous fluorescence emission of laccase indicated that there existed an interaction between Triton X-100 and laccase, which was beneficial to folding and stabilizating of laccase. The binding of Triton X-100 to the laccase surface also mitigated the inactivation effect caused by the free radicals and polymerization products. Under otherwise identical conditions, a lower dosage of laccase was needed for the higher conversion of BPA in the presence of Triton X-100.展开更多
A total of 117 agar-decomposing cultures were isolated from coastal seawater around Qingdao, China. The phenotypic and agarolytic features of an agarolytic isolate, QM38, were investigated. The strain was gram negativ...A total of 117 agar-decomposing cultures were isolated from coastal seawater around Qingdao, China. The phenotypic and agarolytic features of an agarolytic isolate, QM38, were investigated. The strain was gram negative, strictly aerobic, curved rod and polar flagellum. On the basis of several phenotypic characters, biochemical and morphological characters and phylogenetic analysis of the gene coding for the 16S rRNA, the strain was identified as Agarivorans albus strain QM38. This strain can liquefy the agar on the solid agar plate. An excellular agarase activity was determined in liquid culture. The enzyme exhibited maximal activity at 40 ℃, pH 7.6. Its activity was greatly affected by different concentrations of agarose. The highest activity 32 U/ml was achieved in the culture supernatant. The hydrolytic product was analyzed by fluorophore-assisted carbohydrate electrophoresis （FACE）. After complete hydrolysis of agarose, a series of agaro-oligosaccharides were produced. The main products of the enzymes were oligosaccharides in the degree of polymerization （DP） of 2, 4, 6 and 8. Three genes agaD01, agaD02 and agaD03, encodingβ-agarases, had been cloned from genomic DNA of Agarivorans albus strain QM38. The open reading frame of agaDOl, consisted of 2 988 bp, and shared 95.5%-98.9% identity to the β-agarase genes of some strains of Vibrio and Agarivorans. Gene agaD02 comprised 2 868 bp and encoded a 955- amino-acid protein. It showed 97.4% and 98.7~0 identity to the β-agarase genes of strain Vibrio sp. PO-303 and strain Vibrio sp. JT0107, respectively. Only partial sequence of agaD03 gene has been cloned. It showed 96.5% identity to β-agarase gene （agaB） of Pseudoalteromonas sp. CY24, and shared 96.8% identity to β-agarase-c gene of Vibrio sp. PO-303.展开更多
prevalence.A number of clinical workers and researchers have made great efforts to understand the pathogenesis and clinical characteristics and develop effective drugs for treatment.However,no effective drugs with ant...prevalence.A number of clinical workers and researchers have made great efforts to understand the pathogenesis and clinical characteristics and develop effective drugs for treatment.However,no effective drugs with antiviral effects on severe acute respiratory syndrome coronavirus 2 have been discovered currently.Traditional Chinese medicine(TCM)has gained abundant experience in the treatment of infectious diseases for thousands of years.In this review,the authors summarized the clinical outcome,pathogensis and current application of TCM on coronavirus disease 2019.Further,we discussed the potential mechanisms and the future research directions of TCM against severe acute respiratory syndrome coronavirus 2.展开更多
A study was undertaken to investigate the heterotrophic bacterial flora associated with the sea anemones. Samples of the sea anemones Anthopleura midori were collected from the coast of Weihai and bacteria were isolat...A study was undertaken to investigate the heterotrophic bacterial flora associated with the sea anemones. Samples of the sea anemones Anthopleura midori were collected from the coast of Weihai and bacteria were isolated from these samples. Additionally, high numbers of viable bacteria were obtained from the celom wall and surface of anemone, the community of cultivable bacteria was very diverse. As a result of this isolation, 60 strains were obtained, 56 of them were selected for identification and characterization by 16S rRNA gene sequence analysis and limited phenotypic testing. Among these isolates, 16 strains were phylogenetically related to members of the genus Pseudoalteromonas and neighboring taxa. Other isolates included members of the genera Colwcllia, Vibrio, Acinetobactcr, Pseudomonas, Endozoicomonas, Roseovarius, Paraeoceus, Loktanella, Leisingcra, Sulfitobacter, Bacillus, Staphylococcus, Plantibacter, Microbaeterium, Micro- coccus, Joostella, Psychroserpens, Cellulophaga, Krokinobaeter, Polaribacter and Psychrobaeter. Seven potential novel species were found. Among 60 strains, 17 of them can produce proteolytic exoenzyme, 20 can produce lipolytic exoenzyme. Strain NQ8 has strong antagonistic effects on some Vibrio strains. This study demonstrates that the culturable fraction of bacteria from the sea anemones Anthopleura midori is diverse and appears to possess much potential as a source for the discovery of novel bioactive materials.展开更多
Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened...Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened protease-producing bacteria from the South China Sea sediments and analyzed the diversity of their extracellular proteases at the family level through N-terminal amino acid sequencing. Results of the 16 S rRNA gene sequence analysis showed that all screened protease-producing bacteria belonged to the class Gammaproteobacteria and most of them were affiliated with different genera within the orders Alteromonadales and Vibrionales. The Nterminal amino acid sequence analysis for fourteen extracellular proteases from fourteen screened bacterial strains revealed that all these proteases belonged to the M4 family of metalloproteases or the S8 family of serine proteases. This study presents new details on taxa of marine sedimentary protease-producing bacteria and types of their extracellular proteases, which will help to comprehensively understand the process and mechanism of the microbial enzymatic degradation of marine sedimentary organic nitrogen.展开更多
A Glycoside hydrolase （GH） typically contains one catalytic module and varied non-catalytic regions （NCRs）. However, effects of the NCRs to the catalytic modules remain mostly unclear except the carbohydrate-bindi...A Glycoside hydrolase （GH） typically contains one catalytic module and varied non-catalytic regions （NCRs）. However, effects of the NCRs to the catalytic modules remain mostly unclear except the carbohydrate-binding modules （CBMs）. AgaG4 is a GH16 endo-β-agarase of the agarolytic marine bacterium Flammeovirga sp. MY04. The enzyme consists of an extra sugar-binding peptide within the catalytic module, with no predictable CBMs but function-unknown sequences in the NCR, which is a new characteristic of agarase sequences. In this study, we deleted the NCR sequence, a 140-amino acid peptide at the C-terminus and expressed the truncated gene, agaG4-T140, in Escherichia coli. After purification and refolding, the trtmcated agarase rAgaG4-T140 retained the same catalytic temperature and pH value as rAgaG4. Using combined fluorescent labeling, HPLC and MS/MS techniques, we identified the end-products of agarose degradation by rAgaG4-T140 as neoagarotetraose and neoagarohexaose, with a final molar ratio of 1.53：1 and a conversion ratio of approximately 70%, which were similar to those of rAgaG4. However, the truncated agarase rAgaG4-T140 markedly decreased in protein solubility by 15 times and increased in enzymatic activities by 35 times. The oligosaccharide production of rAgaG4-T140 was approximately 25 times the weight of that produced by equimolar rAgaG4. This study provides some insights into the influences of NCR on the biochemical characteristics of agarase AgaG4 and implies some new strategies to improve the properties of a GH enzyme.展开更多
Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-siz...Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-sized crystal particles of magnetic iron minerals,which are only synthesized in lowoxygen environments.Although the mechanism of aerobic repression for magnetosome biomineralization has not yet fully understood,a series of studies have verified that redox modulation is pivotal for magnetosome formation.In this review,these advances in redox modulation for magnetosome biosynthesis are highlighted,mainly including respiration pathway enzymes,specific magnetosome-associated redox proteins,and oxygen-or nitrate-sensing regulators.Furthermore,their relationship during magnetosome biomineralization is discussed to give insight into redox control and biomineralization and inspire potential solutions for the application of respiration pathways to improve the yields of magnetosome.展开更多
A simple, rapid and low-cost method of determination for cordycepin in Cordyceps kyushuensis by capillary zone electrophoresis (CZE) was developed. Based on the finding that there is a high concentration of cordycepin...A simple, rapid and low-cost method of determination for cordycepin in Cordyceps kyushuensis by capillary zone electrophoresis (CZE) was developed. Based on the finding that there is a high concentration of cordycepin in both natural and cultured Cordyceps kyushuensis, the in vitro antitumor activity of cordycepin and the water extracts of Cordyceps kyushuensis has been investigated. This is the first report about the antitumor effect of Cordyceps kyushuensis.展开更多
Cultivable magnetotactic bacteria(MTB) in laboratory can provide sufficient samples for molecular microbiological and magnetic studies.However,a cold-stored MTB strain,such as Magnetospirillum magneticum AMB-1,often l...Cultivable magnetotactic bacteria(MTB) in laboratory can provide sufficient samples for molecular microbiological and magnetic studies.However,a cold-stored MTB strain,such as Magnetospirillum magneticum AMB-1,often loses its ability to synthesize magnetosomes and consequently fails to sense the external magnetic field.It is therefore important to quickly recover vigorous bacteria cells that highly capable of magnetosome producing.In this study,a modified capillary magnetic separation system was designed to recover a deteriorating strain of Magnetospirillum magneticum AMB-1 that long-term cold-stored in a refrigerator.The results show that all cells obtained after a 3-cycle treatment were vigorous and had the ability to produce magnetosomes.Moreover,the 3rd-cycle recovered cells were able to form more magnetosome crystals.Compared with the colony formation method,this new method is time-saving,easily operated,and more efficient for recovering vigorous MTB cells.展开更多
Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession ...Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.展开更多
Previous study demonstrated that Ganoderma meroterpene derivative(GMD)increased the abundance of butyrate-producing bacteria in gut and subsequently delivered anti-metabolic disorder effect of host.To specify the key ...Previous study demonstrated that Ganoderma meroterpene derivative(GMD)increased the abundance of butyrate-producing bacteria in gut and subsequently delivered anti-metabolic disorder effect of host.To specify the key commensal bacteria associating with the beneficial effects,we tried to isolate and compare the microbiota from the cecal samples of GMD-and vehicle-treated ob/ob mice,and further identified butyrate-producing bacterial strains.It was found that Faeciroseburia intestinalis was enriched and 11 strains affiliated to F.intestinalis were cultivated from the gut of GMD-treated mice.In vitro assay attested butyrate production by representative strain of F.intestinalis.Oral administration with F.intestinalis further demonstrated its benefits on regulating hyperglycemia and hyperlipidemia,on decreasing plasma lipopolysaccharide(LPS)and inflammation,and on improving hepatic injuries.Treatment with F.intestinalis effectively enhanced the level of gut butyrate,which subsequently ameliorated the intestinal barrier function and activated epithelial PPAR-γ signaling pathway to regulate microbiome homeostasis in gut.Our study demonstrated that the causal relationship between the butyrate-producing bacteria and the GMD's therapeutic effects and confirmed the important function of the butyrate-producing F.intestinalis in maintaining host metabolism homeostasis.展开更多
基金This work was supported by the National Natural Science Found ation of China(32273000)the Qingdao Demonstration Project for People-benefit from Science and Techniques,China(23-2-8-xdny-14nsh and 24-2-8-xdny-4-nsh)+1 种基金the National Program of Undergraduate Innovation and Entrepreneurship,China(202310435039)the Open Project Fund of State Key Laboratory of Microbial Technology,China(M2023-03)。
文摘Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudoknot)that have been demonstrated to be well conserved.However,it is still unclear whether each stem-loop subdomain,such as a single stem or loop,is also highly conserved.To clarify this issue in the present study,a set of 29 SVA cDNA clones were constructed by site-directed mutagenesis(SDM)on the IRES.The SDM-modified scenarios included:(1)stem-formed complementary sequences exchanging with each other;(2)loop transversion;(3)loop transition;and(4)point mutations.All cDNA clones were separately transfected into cells for rescuing viable viruses,whereas only four SVAs of interest could be recovered,and were genetically stable during 20 passages.One progeny grew significantly slower than the other three did.The dual-luciferase reporter assay showed that none of the SDM-modified IRESes significantly inhibited the IRES activity.Our previous study indicated that a single motif from any of the ten stem structures,if completely mutated,would cause the failure of virus recovery.Interestingly,our present study revealed three stem structures,whose individual complementary sequences could exchange with each other to rescue sequence-modifying SVAs.Moreover,one apical loop was demonstrated to have the ability to tolerate its own full-length transition,also having no impact on the recovery of sequence-modifying SVA.The present study suggested that not every stem-loop structure was strictly conserved in its conformation,while the full-length IRES itself was well conserved.This provides a new research direction on interaction between the IRES and many factors.
基金supported by the Agricultural Scientific and Technological Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2024A04).
文摘Beer is a fermented beverage prepared from water,malted barley,hops,and yeast that has been around for centuries.Alcoholic beverages alter the composition of the gut microbiota,which in turn causes oxidative stress brought on by alcohol,increases intestinal permeability to luminal bacterial products.However,beer has been shown to contain several intriguing non-alcoholic chemicals.Recent research demonstrates that moderate beer drinking could have positive impacts on human health.Beer’s non-alcoholic ingredients have a significant impact on gut microbiota,and this type of diet is known to modulate gut microbiota,which has a variety of effects on the body,including effects on intestinal permeability,mucosal immune function,intestinal motility,antioxidant activity,and anti-inflammatory activity.Although the negative consequences of excessive alcohol intake are widely known,it is still debatable whether or not some non-alcoholic components,such as polyphenols and carbohydrates,have any positive benefits.In this review,we explain the primary benefits of moderate beer consumption on the gut microbiota,which are mostly attributable to non-alcoholic components such polyphenols.Despite any potential advantages of moderating consumption of alcoholic beverages,the lowest alcohol intake is the most secure.
文摘The authors were contacted after publication to request a replacement of Fig.2M in the manuscript.Unfortunately,the authors inadvertently used an image of the model(Vehicle)group liver histopathology section that matches an image published in Fig.2D of Cell Reports(Volume 26,Issue 1,pages 222–235.e5).
基金supported by grants from National Natural Science Foundation of China (32070097 and 91951202)National Key Research and Development Program of China (2019YFA0904800).
文摘The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosynthesis(MES)is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO_(2) into high-value products.The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system.Therefore,this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system.The topics covered include inward extracellular electron transfer pathways,cathode materials,applied cathode potentials,catholyte pH,and reactor configuration.In addition,this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO_(2) into high-value products via MES.
基金foundation support of the National Natural Science Foundation of China(Grant No.82071122)the Program of Taishan Young from Shandong Province+3 种基金Major Innovation Projects in Shandong Province(No.2021SFGC0502)Oral Microbiome Innovation Team of Young Scientist Project of Shandong Province(Grant No.2020KJK001)and Jinan City(2021GXRC021)The National High-level Young Scientist Project Foundation(2019)Excellent Young Scientist Foundation of Shandong Province(Grant No.ZR202102230369)。
文摘Fusobacterium nucleatum(F.nucleatum)is an early pathogenic colonizer in periodontitis,but the host response to infection with this pathogen remains unclear.In this study,we built an F.nucleatum infectious model with human periodontal ligament stem cells(PDLSCs)and showed that F.nucleatum could inhibit proliferation,and facilitate apoptosis,ferroptosis,and inflammatory cytokine production in a dose-dependent manner.The F.nucleatum adhesin Fad A acted as a proinflammatory virulence factor and increased the expression of interleukin(IL)-1β,IL-6 and IL-8.Further study showed that Fad A could bind with PEBP1 to activate the Raf1-MAPK and IKK-NF-κB signaling pathways.Time-course RNA-sequencing analyses showed the cascade of gene activation process in PDLSCs with increasing durations of F.nucleatum infection.NFκB1 and NFκB2 upregulated after 3 h of F.nucleatum-infection,and the inflammatory-related genes in the NF-κB signaling pathway were serially elevated with time.Using computational drug repositioning analysis,we predicted and validated that two potential drugs(piperlongumine and fisetin)could attenuate the negative effects of F.nucleatum-infection.Collectively,this study unveils the potential pathogenic mechanisms of F.nucleatum and the host inflammatory response at the early stage of F.nucleatum infection.
基金financially supported by the National Key Research and Development Program of China(2021YFA0717002)。
文摘Many studies have revealed that gut microbes modulate host metabolism.In this study,we characterized the therapeutic effects of a novel gut commensal Luoshenia tenuis against host metabolic disorders.First,by in silico analysis,we demonstrated that the L.tenuis was prevalent in the gut microbiomes of healthy humans but were depleted specifically in obesity cohorts.Further in vitro cultivation revealed that L.tenuis produced short chain fatty acids that were verified to modulate host metabolism and some other volatile metabolites to benefit hosts by anti-inflammation and anti-tumor.Second,gavage of the L.tenuis significantly decreased the body weight gain and food intake of high-fat diet-feeding C57BL/6J mice,which was in parallel with the changed expression level of genes related to satiety and feeding behavior.We then performed the gavage trial using diet induced obese mice,and it revealed that the administration of L.tenuis alleviated significantly the abnormal glucose and lipid metabolisms and reduced the inflammatory response.In summary,this study revealed a previously-unknown human gut commensal microbe that benefited host metabolism,and set the stage for the development of novel next-generation probiotic applicable for treatment of obesity and related metabolic disorders.
基金supported by the National Natural Science Foundation of China (82003639)Taishan Scholars Program of Shandong Province (tsqn201909049)Qilu Youth Scholar Startup Funding of Shandong University.
文摘Microbial natural products and their derivatives have been developed as a considerable part of clinical drugs and agricultural chemicals.Marine microbial natural products exhibit diverse chemical structures and bioactivities with substantial potential for the development of novel pharmaceuticals.However,discovering compounds with new skeletons from marine microbes remains challenging.In recent decades,multiple approaches have been de-veloped to discover novel marine microbial natural products,among which heterologous expression has proven to be an effective method.Facilitated by large DNA cloning and comparative metabolomic technologies,a few novel bioactive natural products from marine microorganisms have been identified by the expression of their biosynthetic gene clusters(BGCs)in heterologous hosts.Heterologous expression is advantageous for character-izing gene functions and elucidating the biosynthetic mechanisms of natural products.This review provides an overview of recent progress in heterologous expression-guided discovery,biosynthetic mechanism elucidation,and yield optimization of natural products from marine microorganisms and discusses the future directions of the heterologous expression strategy in facilitating novel natural product exploitation.
文摘The production of 2,3-butanediol by Klebsiella pneumoniae from glucose supplemented with different salts was studied. A suitable medium composition was defined by response surface experiments. In a medium containing glu-cose and (NH4)2HPO4, the strain could convert 137.0g of glucose into 52.4g of 2,3-butanediol and 8.4g of acetoin in shaking flasks. The diol yield amounted to 90% of its theoretical value and the productivity was 1—1.5g·L-1·h-1. In fed-batch fermentation, the yield and productivity of diol were further enhanced by maintaining the pH at 6.0. Up to 92.4g of 2,3-butanediol and 13.1g of acetoin per liter were obtained from 215.0g of glucose per liter. The diol yield reached 98% of its theoretical value and the productivity was up to 2.1g·L-1·h-1.
基金the National Natural Science Foundation of China(No.30470052)the National Basic Research Program of China(Nos.2003CB716006 and 2004CB719702)the Natural Science Research Foundation for the Doctoral Program of Edu-cation Ministry of China(No.20040422042).
文摘Two uridine auxotrophic mutants of Trichoderma reesei were isolated by resistance to 5-fluoroorotic acid after UV mutagenesis. One mutant, called M23, was complemented with the Aspergillus niger pyrG gene carried by plasmid pAB4-1. A mutated pyrG gene of M23 was cloned and DNA sequencing analysis indicated that a cytosine was inserted into the 934―939 oligo dC position of the pyrG coding region, resulted in a frameshift mutation. Transformation efficiency was approximately 200―300 transformants per microgram of DNA with plasmid pAB4-1. Stable transformants were obtained by monosporic culture and showed to be prototroph after successive propagation. Vitreoscilla hemoglobin expression plasmid pUCVHb was cotransformed with plasmid pAB4-1 and attained a transformation efficiency of 71.8% or of 26.1% with pAN7-1. Southern blot analysis of the transformants demonstrated that plasmid pUCVHb was integrated into the chromosomal DNA. The experimental results demonstrated that the pyrG-based system was more efficient and timesaving than the conventional hygromycin B resistance-based transformation system.
文摘The laccase-catalyzed conversion of bisphenol A （BPA） in aqueous solutions was studied in the absence and presence of nonionic surfactant Triton X-100. It was found that the addition of Triton X-100 into the reaction system increased the conversion of BPA, especially near the critical micelle concentration of Triton X-100. Also it was found that the stability of laccase was greatly improved in the presence of TritonX-100. Studies on the endogenous fluorescence emission of laccase indicated that there existed an interaction between Triton X-100 and laccase, which was beneficial to folding and stabilizating of laccase. The binding of Triton X-100 to the laccase surface also mitigated the inactivation effect caused by the free radicals and polymerization products. Under otherwise identical conditions, a lower dosage of laccase was needed for the higher conversion of BPA in the presence of Triton X-100.
基金Shandong Provincial Natural Science Foundation,China under contract No. ZR2009EQ009Independent Innovation Foundation of Shandong University (IIFSDU)Key Lab of Marine Bioactive Substance and Modern Analytical Technique,SOA,China under contract No. MBSMAT-2009-07
文摘A total of 117 agar-decomposing cultures were isolated from coastal seawater around Qingdao, China. The phenotypic and agarolytic features of an agarolytic isolate, QM38, were investigated. The strain was gram negative, strictly aerobic, curved rod and polar flagellum. On the basis of several phenotypic characters, biochemical and morphological characters and phylogenetic analysis of the gene coding for the 16S rRNA, the strain was identified as Agarivorans albus strain QM38. This strain can liquefy the agar on the solid agar plate. An excellular agarase activity was determined in liquid culture. The enzyme exhibited maximal activity at 40 ℃, pH 7.6. Its activity was greatly affected by different concentrations of agarose. The highest activity 32 U/ml was achieved in the culture supernatant. The hydrolytic product was analyzed by fluorophore-assisted carbohydrate electrophoresis （FACE）. After complete hydrolysis of agarose, a series of agaro-oligosaccharides were produced. The main products of the enzymes were oligosaccharides in the degree of polymerization （DP） of 2, 4, 6 and 8. Three genes agaD01, agaD02 and agaD03, encodingβ-agarases, had been cloned from genomic DNA of Agarivorans albus strain QM38. The open reading frame of agaDOl, consisted of 2 988 bp, and shared 95.5%-98.9% identity to the β-agarase genes of some strains of Vibrio and Agarivorans. Gene agaD02 comprised 2 868 bp and encoded a 955- amino-acid protein. It showed 97.4% and 98.7~0 identity to the β-agarase genes of strain Vibrio sp. PO-303 and strain Vibrio sp. JT0107, respectively. Only partial sequence of agaD03 gene has been cloned. It showed 96.5% identity to β-agarase gene （agaB） of Pseudoalteromonas sp. CY24, and shared 96.8% identity to β-agarase-c gene of Vibrio sp. PO-303.
文摘prevalence.A number of clinical workers and researchers have made great efforts to understand the pathogenesis and clinical characteristics and develop effective drugs for treatment.However,no effective drugs with antiviral effects on severe acute respiratory syndrome coronavirus 2 have been discovered currently.Traditional Chinese medicine(TCM)has gained abundant experience in the treatment of infectious diseases for thousands of years.In this review,the authors summarized the clinical outcome,pathogensis and current application of TCM on coronavirus disease 2019.Further,we discussed the potential mechanisms and the future research directions of TCM against severe acute respiratory syndrome coronavirus 2.
基金The State Key Laboratory of Microbial Technology under contract No. M2010-04Independent Innovation Foundation of Shandong University (IIFSDU)+1 种基金the National Natural Science Foundation of China under contract No. 40730847Special Non-profit Research Project from Ministry of Agriculture of the Peoples Republic of China under contract No. nyhyzx07-046
文摘A study was undertaken to investigate the heterotrophic bacterial flora associated with the sea anemones. Samples of the sea anemones Anthopleura midori were collected from the coast of Weihai and bacteria were isolated from these samples. Additionally, high numbers of viable bacteria were obtained from the celom wall and surface of anemone, the community of cultivable bacteria was very diverse. As a result of this isolation, 60 strains were obtained, 56 of them were selected for identification and characterization by 16S rRNA gene sequence analysis and limited phenotypic testing. Among these isolates, 16 strains were phylogenetically related to members of the genus Pseudoalteromonas and neighboring taxa. Other isolates included members of the genera Colwcllia, Vibrio, Acinetobactcr, Pseudomonas, Endozoicomonas, Roseovarius, Paraeoceus, Loktanella, Leisingcra, Sulfitobacter, Bacillus, Staphylococcus, Plantibacter, Microbaeterium, Micro- coccus, Joostella, Psychroserpens, Cellulophaga, Krokinobaeter, Polaribacter and Psychrobaeter. Seven potential novel species were found. Among 60 strains, 17 of them can produce proteolytic exoenzyme, 20 can produce lipolytic exoenzyme. Strain NQ8 has strong antagonistic effects on some Vibrio strains. This study demonstrates that the culturable fraction of bacteria from the sea anemones Anthopleura midori is diverse and appears to possess much potential as a source for the discovery of novel bioactive materials.
基金The AoShan Talents Cultivation Program supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2017ASTCP-OS14the National Natural Science Foundation of China under contract Nos 31670063,31670497 and 31870052+1 种基金the Taishan Scholars Program of Shandong Province under contract No.2009TS079the Science and Technology Basic Resources Investigation Program of China under contract No.2017FY100804
文摘Protease-producing bacteria and their extracellular proteases are key players in degrading organic nitrogen to drive marine nitrogen cycling and yet knowledge on both of them is still very limited. This study screened protease-producing bacteria from the South China Sea sediments and analyzed the diversity of their extracellular proteases at the family level through N-terminal amino acid sequencing. Results of the 16 S rRNA gene sequence analysis showed that all screened protease-producing bacteria belonged to the class Gammaproteobacteria and most of them were affiliated with different genera within the orders Alteromonadales and Vibrionales. The Nterminal amino acid sequence analysis for fourteen extracellular proteases from fourteen screened bacterial strains revealed that all these proteases belonged to the M4 family of metalloproteases or the S8 family of serine proteases. This study presents new details on taxa of marine sedimentary protease-producing bacteria and types of their extracellular proteases, which will help to comprehensively understand the process and mechanism of the microbial enzymatic degradation of marine sedimentary organic nitrogen.
基金financially supported by the Open Research Fund Program of Shandong Provincial Key Laboratory of Glycoscience&Glycotechnology(Ocean University of China)KLGG(OUC)201301the National Natural Science Foundation of China Grants 31300664 and 31130004the State Key Laboratory of Microbial Technology Grant(Shandong University)M2013-11
文摘A Glycoside hydrolase （GH） typically contains one catalytic module and varied non-catalytic regions （NCRs）. However, effects of the NCRs to the catalytic modules remain mostly unclear except the carbohydrate-binding modules （CBMs）. AgaG4 is a GH16 endo-β-agarase of the agarolytic marine bacterium Flammeovirga sp. MY04. The enzyme consists of an extra sugar-binding peptide within the catalytic module, with no predictable CBMs but function-unknown sequences in the NCR, which is a new characteristic of agarase sequences. In this study, we deleted the NCR sequence, a 140-amino acid peptide at the C-terminus and expressed the truncated gene, agaG4-T140, in Escherichia coli. After purification and refolding, the trtmcated agarase rAgaG4-T140 retained the same catalytic temperature and pH value as rAgaG4. Using combined fluorescent labeling, HPLC and MS/MS techniques, we identified the end-products of agarose degradation by rAgaG4-T140 as neoagarotetraose and neoagarohexaose, with a final molar ratio of 1.53：1 and a conversion ratio of approximately 70%, which were similar to those of rAgaG4. However, the truncated agarase rAgaG4-T140 markedly decreased in protein solubility by 15 times and increased in enzymatic activities by 35 times. The oligosaccharide production of rAgaG4-T140 was approximately 25 times the weight of that produced by equimolar rAgaG4. This study provides some insights into the influences of NCR on the biochemical characteristics of agarase AgaG4 and implies some new strategies to improve the properties of a GH enzyme.
基金Supported by the National Natural Science Foundation of China(No.41706165)the Fundamental Research Funds of Shandong University(No.2019HW022)。
文摘Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-sized crystal particles of magnetic iron minerals,which are only synthesized in lowoxygen environments.Although the mechanism of aerobic repression for magnetosome biomineralization has not yet fully understood,a series of studies have verified that redox modulation is pivotal for magnetosome formation.In this review,these advances in redox modulation for magnetosome biosynthesis are highlighted,mainly including respiration pathway enzymes,specific magnetosome-associated redox proteins,and oxygen-or nitrate-sensing regulators.Furthermore,their relationship during magnetosome biomineralization is discussed to give insight into redox control and biomineralization and inspire potential solutions for the application of respiration pathways to improve the yields of magnetosome.
文摘A simple, rapid and low-cost method of determination for cordycepin in Cordyceps kyushuensis by capillary zone electrophoresis (CZE) was developed. Based on the finding that there is a high concentration of cordycepin in both natural and cultured Cordyceps kyushuensis, the in vitro antitumor activity of cordycepin and the water extracts of Cordyceps kyushuensis has been investigated. This is the first report about the antitumor effect of Cordyceps kyushuensis.
基金Supported by the Natural Science Foundation of Shandong Province,China(No.2006ZRB01973)the National Natural Science Foundation of China(Nos.40821091,40325011)
文摘Cultivable magnetotactic bacteria(MTB) in laboratory can provide sufficient samples for molecular microbiological and magnetic studies.However,a cold-stored MTB strain,such as Magnetospirillum magneticum AMB-1,often loses its ability to synthesize magnetosomes and consequently fails to sense the external magnetic field.It is therefore important to quickly recover vigorous bacteria cells that highly capable of magnetosome producing.In this study,a modified capillary magnetic separation system was designed to recover a deteriorating strain of Magnetospirillum magneticum AMB-1 that long-term cold-stored in a refrigerator.The results show that all cells obtained after a 3-cycle treatment were vigorous and had the ability to produce magnetosomes.Moreover,the 3rd-cycle recovered cells were able to form more magnetosome crystals.Compared with the colony formation method,this new method is time-saving,easily operated,and more efficient for recovering vigorous MTB cells.
基金The work was supported by the Hi-Tech Research and Development Program of China under contract Nos 2006AA09Z414 and 2007AA091903；the China Ocean Mineral Resources R ＆ D Association under contract No. DYXM - 115 - 02 - 2 - 6；the National Natural Science Foundation of China under contract No. Z2004D02；the Natural Science Foundation of Shandong Province of China under contract No. Z2004D02；the Foundation for Young Excellent Scientists in Shandong Province of China under contract No. 2006BS02002；the Program for New Century Excellent Talents in University under contract No. NCET - 06 - 0578.
文摘Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.
基金supported by the National Key R&D program of China(2019YFA0905602)the National Natural Science Foundation of China(81773614)the Strategic Priority Research Program of Chinese Academy of Sciences(grant No.XDB 38020300).
文摘Previous study demonstrated that Ganoderma meroterpene derivative(GMD)increased the abundance of butyrate-producing bacteria in gut and subsequently delivered anti-metabolic disorder effect of host.To specify the key commensal bacteria associating with the beneficial effects,we tried to isolate and compare the microbiota from the cecal samples of GMD-and vehicle-treated ob/ob mice,and further identified butyrate-producing bacterial strains.It was found that Faeciroseburia intestinalis was enriched and 11 strains affiliated to F.intestinalis were cultivated from the gut of GMD-treated mice.In vitro assay attested butyrate production by representative strain of F.intestinalis.Oral administration with F.intestinalis further demonstrated its benefits on regulating hyperglycemia and hyperlipidemia,on decreasing plasma lipopolysaccharide(LPS)and inflammation,and on improving hepatic injuries.Treatment with F.intestinalis effectively enhanced the level of gut butyrate,which subsequently ameliorated the intestinal barrier function and activated epithelial PPAR-γ signaling pathway to regulate microbiome homeostasis in gut.Our study demonstrated that the causal relationship between the butyrate-producing bacteria and the GMD's therapeutic effects and confirmed the important function of the butyrate-producing F.intestinalis in maintaining host metabolism homeostasis.
