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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 288-296页

作者： Guanying Wang Gang Zhang Xiongjun Shao State key laboratory of Biocatalysis and Enzyme Engineering/Hubei key laboratory of industrial biotechnology School of Life SciencesHubei UniversityWuhan 430062China

Lime pretreatment on maize stover was conducted with various pretreatment conditions selected by central composite *** and lignin contents in pretreated maize stover were relatively *** of glucose monomer and oligomers decreased while concentration of xylooligomers increased in the pretreatment hydrolysate with increasing pretreatment *** overall carbohydrate recovery was at least 85%for the conditions *** removal during pretreatment was found to have a linear correlation with lignin *** had a higher effect in enhancing carbohydrate solubilization for enzymatic hydrolysis than that for *** *** all the pretreated solids,Clostridium thermocellum fermentation was found to result in much higher carbohydrate solubilization than enzymatic hydrolysis with a cellulase loading of 8 mg/g solids and a xylanase loading of 2 mg/g *** solubilization was found to have a linear correlation with lignin removal during lime pretreatment for both enzymatic hydrolysis and *** *** the current challenges,this research provides a new idea for the industrial application of lignocellulosic biorefinery.

关键词： central composite design lime pretreatment enzymatic hydrolysis clostridium thermocellum carbohydrate solubilization

Microbial community dynamics and flavor formation mechanisms during fermentation of fermented chilies from different regions based on macro-genome sequencing， SPME-GC-MS， electronic nose， and electronic tongue

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Food Science and Human Wellness 2024年

作者： Hui Liao Yi Luo Xiang Lian Hussain Asif Xinlei Huang Xiaole Xia The key laboratory of industrial biotechnology， Ministry of Education， School of biotechnology， Jiangnan University College of Food Science and Engineering， Tianjin University of Science & Technology

Fermented chili products are popular traditional fermented foods around the world. However， differences in microbial communities in fermented chilies from different regions and how they affect the flavor compounds in chili fermentation have not been reported. In this study， the dynamics of flavor compounds and microbial communities in fermented chilies from Sichuan， Guizhou， and Hunan were systematically investigated by macro-genome sequencing， solid phase microextraction-gas chromatograph-mass spectrometry (SPME-GC-MS)， electronic nose， and electronic tongue techniques. Simultaneously， the microbial metabolic mechanisms and the relationship between flavor compounds and microbiome were unraveled through staged and simulated fermentation analysis. The results showed that 53 chemical odorants， including alcohols， esters， aldehydes， and acids， were identified as chemical markers to differentiate the regional samples. Twelve microbial species， including Staphylococcus xylosus， Unclassified staphylococcus species， Weissella confusus， Lactococcus cremoris， Lactococcus garvieae， Lactiplantibacillus sakei， Pediciococcus propionicigenes， Pediciococcus idahonensis， Pediciococcus aciditolerans， Nocardioides antri， Debaryomyces hansenii， and Colletotrichum scovillei， were identified as microbial markers to differentiate the regional samples. Correlation analysis showed that Lactobacillaceae was associated with fruity， floral， spicy， and fatty aromas. The electronic nose and tongue analysis results showed that 9 flavor and 8 taste indicators significantly differed between regional samples (P < 0.05). Additionally， flavor compounds and microbial diversity were robust under initial selection stress and showed higher diversity under metabolome-microbiome interactions. Importantly， simulated fermentation confirmed that metabolome-microbiome interactions drove the shift in microbial structure， metabolism， and flavor in regionally fermented chilies. These results provide insights into

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{1012}twin–twin intersection-induced lattice rotation and dynamic recrystallization in Mg–6Al–3Sn–2Zn alloy

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Journal of Magnesium and Alloys 2024年第4期12卷 1529-1539页

作者： Bin-Jiang Lv Sen Wang Fu-Hao Gao Ning Cui Yi-Nan Li Tie-Wei Xu Feng Guo School of Mechanical and Automotive Engineering Qingdao University of Technology266520China key lab of industrial Fluid Energy Conservation and Pollution Control Qingdao University of Technology266520China

This study investigated the formation mechanism of new grains due to twin–twin intersections in a coarse-grained Mg–6Al–3Sn–2Zn alloy during different strain rates of an isothermal *** results of electron backscattered diffraction investigations showed that the activated twins were primarily{1012}tension twins,and 60°boundaries formed due to twin–twin intersections under different strain *** twin variants with 60°boundaries transformed into new grains through lattice rotations at a low strain rate(0.01 s^(−1)).At a high strain rate(10 s^(−1)),the regions surrounded by subgrain boundaries through high-density dislocation arrangement and the 60°boundaries transformed into new grains via dynamic recrystallization.

关键词： Mg alloy Twin-twin intersection Lattice rotation Dynamic recrystallization

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Characterization of the effects of hyaluronan oligosaccharides on human gut microbiota using a simulated batch fermentation system

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Food Science and Human Wellness 2024年

作者： Xinwei Gao Hongkang Zhu Litao Hu Jieyu Sun Wenjie Zuo Ping Liu Yang Wang Guocheng Du Zhen Kang The Science Center for Future Foods， Jiangnan University The key laboratory of Carbohydrate Chemistry and biotechnology， Ministry of Education， Jiangnan University The key laboratory of industrial biotechnology， Ministry of Education， School of biotechnology， Jiangnan University School of Food Science and Technology， Jiangnan University

The prebiotic effects of hyaluronan (HA) are widely recognized， contributing to improved gut health and immune modulation. Despite its extensive use as dietary supplement， the specific interactions between HA oligosaccharides (o-HAs) and the gut microbiome remain largely unexplored. To investigate its role and metabolic fate in gut homeostasis， 200 mg/day of o-HAs (average molecule weight 1k Da) were added to an automated computer-controlled SIMulator of the Gastrointestinal tract (SIMGI). The results revealed a significant reshaping of the intestinal flora composition by o-HAs， notably reducing the Firmicutes/Bacteroides ratio. Fermentation of o-HAs by gut microbiota significantly increased the abundance of Bifidobacteria， Prevotellaceae＿Prevotella， Dialister， Eubacterium， and Sutterella， but decreased that of Catenibacterium， Oscillospira， Klebsiella， and Citrobacter (P < 0.05). This corresponded with significant enhancements in the content of short-chain fatty acids (SCFAs) such as acetic acid， propionic acid and n-butyric acid， highlighting the significant impact of o-HAs at the genus level. Furthermore， analysis of microbial function predicted the downregulation of pathological events in nine human diseases， particularly infectious ones (parasitic and bacterial). Potential inhibitions were observed in metabolic pathways associated with pentose and glucuronate interconversions as well as cationic antimicrobial peptide resistance. These findings underscore the in vitro prebiotic effects of o-HAs and their potential relevance in managing diverticular diseases or preventing metabolic disorders through the regulation of gut microbiota.

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Structure， properties， bioactivities and structure-activity relationships of polysaccharides from Nostoc flagelliforme grown under three different culture conditions

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Food Science and Human Wellness 2024年

作者： Yanru Li Shigang Shen Longfei Wang Mengyuan Li Yan Zhang Shiru Jia Ruiying Zhu Peipei Han State key laboratory of Food Nutrition and Safety， key laboratory of industrial Fermentation Microbiology， Ministry of Education， College of biotechnology， Tianjin University of Science and Technology

The physicochemical properties， structural characteristics， antioxidant， radioprotective and lipid-lowering activities， as well as the underlying structure-activity relationships of polysaccharides extracted from Nostoc flagelliforme grown under normal （WL-EPS-1）， salt stress （NaCl-EPS-1） and mixotrophic culture conditions （Glu-EPS-1） were studied. The results demonstrated that WL-EPS-1， NaCl-EPS-1 and Glu-EPS-1 were heteropolysaccharides comprising different proportions of monosaccharides and uronic acid， with different average molecular weights of 0.99 × 103， 1.09 × 103and 1.18 × 103kDa， respectively. Their intrinsic viscosity values were significantly different， at 24.72 dL/g， 29.98 dL/g and 41.06 dL/g， respectively. The functional groups of polysaccharides were not greatly affected， but the chemical composition， triple-helix structure， chain length and surface morphology were significantly influenced by culture conditions. In vitro bioactivity assays showed that the antioxidant activity generally increased in the order of WL-EPS-1 < NaCl-EPS-1 < Glu-EPS-1， while NaCl-EPS-1 had the best radioprotective effect， and Glu-EPS-1 had the best lipid-lowering effect. In addition， the structure-activity relationship of the polysaccharides was analyzed by Partial Least Squares （PLS）， which revealed that the most important factors affecting the antioxidant， radioprotective and lipid-lowering activities of polysaccharides were viscosity and molecular weight. This study provides a strategy for obtaining high-bioactivity polysaccharides by appropriate regulation of culture conditions， as well as opening new directions for the molecular modification of polysaccharides.

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Rational protein engineering of thermostable heparinase I from Bacteroides thetaiotaomicron for highly efficient heparin degradation

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Food Science and Human Wellness 2024年

作者： Chuan Zhang Ruohan Zhao Leilei Yu Qixiao Zhai Jianxin Zhao Hao Zhang Xuegang Luo Fengwei Tian Wei Chen State key laboratory of Food Science and Technology， Jiangnan University School of Food Science and Technology， Jiangnan University key laboratory of industrial Fermentation Microbiology of the Ministry of Education & Tianjin key lab of industrial Microbiology， College of biotechnology， Tianjin University of Science and Technology National Engineering Research Center for Functional Food， Jiangnan University

Heparin， a glycosaminoglycan， is a stable source of carbon that supports the growth of microorganisms in the human intestine. It is also a commonly used anticoagulant drug in clinical practice， with significant therapeutic effects. Low molecular weight heparin （LMWH） is a highly active low molecular weight fragment obtained via enzymatic reaction or the chemical degradation of heparin. LMWH has been applied globally in the prevention and treatment of venous thromboembolism in thrombosis patients. Simultaneously， as a potential prebiotic， because of its low molecular weight， LMWH can be well degraded by the gut microbiota to maintain intestinal balance. Enzymatic heparin degradation has recently emerged as a viable disposal method for LMWH preparation; however， only very few benchmark enzymes have been thoroughly described and subjected to protein engineering to improve their properties over the past few years. The commercialization of enzymes will require the development of robustly engineered enzymes that meet the demands of industrial processes. Herein， we report a rational protein engineering strategy that includes molecular dynamic simulations of flexible amino acid mutations and disulfide bond screening. Several Bt-HepI mutants were obtained and screened for high thermal stability. We obtained the Bt-HepID204C/K208C/H189W/Q198Rvariant， which features a stabilized protein surface structure， with a 1.3-fold increase in kcat/Km， a 2.44-fold increase in thermal stability at 50℃， and a 1.8-fold decrease in the average molecular weight of LMWH produced at 40℃ compared with that seen with Bt-HepIWT. Our study establishes a strategy to engineer thermostable HepI to underpin its industrial applications.

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Two H3K36 methyltransferases differentially associate with transcriptional activity and enrichment of facultative heterochromatin in rice blast fungus

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aBIOTECH 2024年第1期5卷 1-16页

作者： Mengting Xu Ziyue Sun Huanbin Shi Jiangnan Yue Xiaohui Xiong Zhongling Wu Yanjun Kou Zeng Tao Ministry of Agriculture key laboratory of Molecular Biology of Crop Pathogens and Insects Institute of BiotechnologyZhejiang UniversityHangzhou 310058China State key lab of Rice Biology and Breeding China National Rice Research InstituteHangzhou 310021China

Di-and tri-methylation of lysine 36 on histone H3(H3K36me2/3)is catalysed by histone methyltransferase Set2,which plays an essential role in transcriptional *** there is a single H3K36 methyltransferase in yeast and higher eukaryotes,two H3K36 methyltransferases,Ash1 and Set2,were present in many filamentous ***,their roles in H3K36 methylation and transcriptional regulation remained *** with methods of RNA-seq and ChIP-seq,we revealed that both Ash1 and Set2 are redundantly required for the full H3K36me2/3 activity in Magnaporthe oryzae,which causes the devastating worldwide rice blast ***1 and Set2 distinguish genomic H3K36me2/3-marked regions and are differentially associated with repressed and activated transcription,***,Ash1-catalysed H3K36me2 was co-localized with H3K27me3 at the chromatin,and Ash1 was required for the enrichment and transcriptional silencing of H3K27me3-occupied *** the different roles of Ash1 and Set2,in H3K36me2/3 enrichment and transcriptional regulation on the stress-responsive genes,they differentially respond to various stresses in ***,we reveal a novel mechanism by which two H3K36 methyltransferases catalyze H3K36me2/3 that differentially associate with transcriptional activities and contribute to enrichment of facultative heterochromatin in eukaryotes.

关键词： Ash1 Facultative heterochromatin H3K36me2/3 Magnaporthe oryzae Set2 Transcriptional regulation

A new era for paclitaxel biosynthesis is coming

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Molecular Plant 2024年第3期17卷 370-371页

作者： Xiaonan Liu Xiaoxi Zhu Jian Cheng Huifeng Jiang key laboratory of Engineering Biology for Low-carbon Manufacturing Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin 300308China National Center of Technology Innovation for Synthetic Biology Tianjin 300308China

Paclitaxel(Taxol)stands out as a tetracyclic diterpenoid natural product derived from the endangered plant *** as a pivotal broad-spectrum anticancer drug,it has garnered widespread attention due to its low yield,intricate structure,unique anticancer mechanism,and remarkable efficacy(Tong et al.,2021).Although chemists achieved the total synthesis of paclitaxel 30 years ago,after decades of research,the natural biosynthetic pathway for its production remains an enigma(Ajikumar et al.,2010;Malci et al.,2023).A recent breakthrough,published in Molecular Plant by Alisdair ***'s team,unveils a minimal gene set of 18 genes required for paclitaxel biosynthesis(Zhang et al.,2023),representing a significant mark toward unraveling the entire biosynthetic pathway and enhancing paclitaxel production efficiency.

关键词： breakthrough representing synthesis

A growth-regulating factor 7(GRF7)-mediated gene regulatory network promotes leaf growth and expansion in sugarcane

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The Crop Journal 2024年第2期12卷 422-431页

作者： Qiaoyu Wang Yihan Li Dadong Lin Xiaoxi Feng Yongjun Wang Tianyou Wang Hongyan Ding Jisen Zhang State key lab for Conservation and Utilization of Subtropical AgroBiological Resources and Guangxi key lab for Saccharum Biology Guangxi UniversityNanning 530005GuangxiChina Center for Genomics and biotechnology/Fujian Provincial key laboratory of Haixia Applied Plant Systems Biology/key laboratory of Saccharum Biology and Genetic Breeding/National Engineering Research Center for Saccharum Fujian Agriculture and Forestry UniversityFuzhou 350002FujianChina

Knowledge of the function of growth-regulating factors(GRFs)in sugarcane(Saccharum officinarum and ***)growth and development could assist breeders in selecting desirable plant ***,limited information about GRFs is available in Saccharum due to their *** this study,22 GRFs were identified in the two species and their conserved domains,gene structures,chromosome location,and synteny were ***7 expression varied among tissues and responded to diurnal ***7-YFP was localized preferentially in the nucleus and appears to act as a transcriptional ***7 positively regulated the size and length of rice leaves,possibly by regulating cell size and plant *** seven potential transcription factors binding to the SsGRF7 promoter in ***,four showed positive expression patterns,and two showed negative expression patterns relative to SsGRF7.

关键词： Expression analysis Growth-regulating factor Leaf development Sugarcane Transcription factors

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The biological functions and metabolic pathways of valine in swine

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Journal of Animal Science and biotechnology 2024年第1期15卷 20-34页

作者： Chuni Wang Yao Peng Yiru Zhang Juan Xu Sheng Jiang Leli Wang Yulong Yin Institute of Subtropical Agriculture Chinese Academy of SciencesChangshaChina Hunan Provincial key laboratory of Animal Intestinal Function and Regulation College of Life SciencesHunan Normal UniversityChangshaChina Tianjin Institute of industrial biotechnology Chinese Academy of SciencesTianjinChina

Valine is an essential amino acid and a type of branched-chain amino acid. Due to the involvement of branchedchain amino acids in various metabolic pathways, there has been a surge of interests in valine nutrition and its role in animal physiology. In pigs, the interactions between valine and other branched-chain amino acids or aromatic amino acids are complex. In this review, we delve into the interaction mechanism, metabolic pathways, and biological functions of valine. Appropriate valine supplementation not only enhances growth and reproductive performances, but also modulates gut microbiota and immune functions. Based on past observations and interpretations, we provide recommended feed levels of valine for weaned piglets, growing pigs, gilts, lactating sows, barrows and entire males. The summarized valine nutrient requirements for pigs at different stages offer valuable insights for future research and practical applications in animal husbandry.

关键词： Additional dosage Biological function Metabolic pathway Pig Valine

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