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Spontaneous mutations and mutational responses to penicillin treatment in the bacterial pathogen Streptococcus pneumoniae D39

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Marine Life Science & Technology 2024年第3期6卷 198-211页

作者： Wanyue Jiang Tongtong Lin Jiao Pan Caitlyn ERivera Clayton Tincher Yaohai Wang Yu Zhang Xiang Gao Yan Wang Ho‑Ching T.Tsui Malcolm E.Winkler Michael Lynch Hongan Long Institute of Evolution and Marine Biodiversity KLMMEOcean University of ChinaQingdao 266003China Laboratory for Marine Biology and Biotechnology Laoshan LaboratoryQingdao 266237China Department of Biology Indiana UniversityBloomingtonIN 47405USA School of Mathematics Science Ocean University of ChinaQingdao 266000China State Key Laboratory of microbial Technology Microbial Technology InstituteSchool of Life ScienceShandong UniversityQingdao 266237China Biodesign Center for Mechanisms of Evolution Arizona State UniversityTempeAZ 85281USA

Bacteria with functional DNA repair systems are expected to have low mutation rates due to strong natural selection for genomic ***,our study of the wild-type Streptococcus pneumoniae D39,a pathogen responsible for many common diseases,revealed a high spontaneous mutation rate of 0.02 per genome per cell division in mutation-accumulation(MA)*** rate is orders of magnitude higher than that of other non-mutator bacteria and is characterized by a high mutation bias in the A/T *** high mutation rate may have resulted from a reduction in the overall efficiency of selection,conferred by the tiny effective population size in *** line with this,*** D39 also exhibited the lowest DNA mismatch-repair(MMR)efficiency among *** with the antibiotic penicillin did not elevate the mutation rate,as penicillin did not induce DNA damage and *** lacks a stress response *** findings suggested that the MA results are applicable to within-host scenarios and provide insights into pathogen evolution.

关键词： Neutral evolution Mutation spectrum Antibiotics DNA mismatch repair Oxidative damage repair

Tal6b/AvrXa27A,a hidden TALE targeting the susceptibility gene OsSWEET11a and the resistance gene Xa27 in rice

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Plant Communications 2024年第2期5卷 122-134页

作者： Zhengyin Xu Xiameng Xu Ying Li Linlin Liu Qi Wang Yijie Wang Yong Wang Jiali Yan Guanyun Cheng Lifang Zou Bo Zhu Gongyou Chen Shanghai Collaborative Innovation Center of Agri-Seeds School of Agriculture and BiologyShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of microbial Metabolism Shanghai Jiao Tong UniversityShanghai 200240China

Xanthomonas oryzae ***(Xoo)secretes transcription activator-like effectors(TALEs)to activate rice susceptibility(S)genes,causing bacterial blight(BB),as well as resistance(R)genes,leading to de-fense against *** activation follows a gene-for-gene paradigm that results in an arms race between the TALE of the pathogen and effector-binding elements(EBEs)in the promoters of host *** this study,we characterized a novel TALE,designated Tal6b/AvrXa27A,that activates the rice S gene OsSWEET11a and the rice R gene ***6b/AvrXa27A is a member of the AvrXa27/TalAO class and contains 16 repeat variable diresidues(RVDs);one RVD is altered and one is deleted in Tal6b/AvrXa27A compared with AvrXa27,a known avirulence(avr)effector of ***6b/AvrXa27A can transcriptionally activate the expression of Xa27 and OsSWEET11a via EBEs in their corresponding promoters,leading to effector-triggered immunity and susceptibility,*** 16 RVDs in Tal6b/AvrXa27A have no obvious similarity to the 24 RVDs in the effector PthXo1,but EBETal6b and EBEPthXo1 are overlapped in the OsSWEET11a ***6b/AvrXa27A is prevalent among Asian Xoo isolates,but PthXo1 has only been reported in the Philippine strain *** editing of EBETal6b in the OsSWEET11a pro-moter further confirmed the requirement for OsSWEET11a expression in Tal6b/AvrXa27A-dependent susceptibility to ***,Tal6b/AvrXa27A resulted in higher transcription of Xa27 than of OsSWEET11a,which led to a strong,rapid resistance response that blocked disease *** suggest that Tal6b/AvrXa27A has a dual function:triggering resistance by activating Xa27 gene expression as an avirulence factor and inducing transcription of the S gene OsSWEET11a,resulting in ***,Tal6b/AvrXa27A,but not AvrXa27,can bind to the promoter of *** underlying recognition mechanism for this binding remains unclear but appears to deviate from the currently accepted TALE code.

关键词： Xanthomonas oryzae pv.oryzae TALE AvrXa27 tal6b Xa27 OsSWEET11a

Rational design of a highly active N-glycosyltransferase mutant using fragment replacement approach

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Engineering Microbiology 2024年第1期4卷 10-17页

作者： Jiangyu Yang Kun Li Yongheng Rong Zhaoxi Liu Xiaoyu Liu Yue Yu Wenjing Shi Yun Kong Min Chen State Key Laboratory of microbial Technology Shandong UniversityQingdao 266237China National Glycoengineering Research Center Shandong UniversityQingdao 266237China

The modularity of carbohydrate-active enzymes facilitates that enzymes with different functions have similar ***,because of the complex structure of the enzyme active sites and the epistatic effects of various mutations on enzyme activity,it is difficult to design enzymes with multiple mutation sites using conventional *** this study,we designed multi-point mutants by fragment replacement in the donor-acceptor binding pocket of Actinobacillus pleuropneumoniae N-glycosyltransferase(ApNGT)to obtain novel *** fragments were selected from a customized glycosyltransferase *** stability and substrate-binding energy of the three fragment replacement mutants were calculated in comparison with wild-type ApNGT,and mutants with top-ranking stability and middle-ranking substrate-binding energy were chosen for priority experimental *** found that a mutant called F13,which increased the glycosylation efficiency of the natural substrate by 1.44 times,the relative conversion of UDP-galactose by 14.2 times,and the relative conversion of UDP-xylose from almost 0 to 78.6%.Most importantly,F13 mutant acquired an entirely new property,the ability to utilize UDP-glucuronic *** one hand,this work shows that replacing similar fragments in the donoracceptor binding pocket of the enzyme might provide new ideas for designing mutants with new properties;on the other hand,F13 mutant is expected to play an important role in targeted drug delivery.

关键词： N-glycosyltransferase Computational design Glycoprotein Fragment replacement GT41

Selective butyric acid production from CO_(2)and its upgrade to butanol in microbial electrosynthesis cells

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Environmental Science and Ecotechnology 2024年第1期17卷 119-127页

作者： Meritxell Romans-Casas Laura Feliu-Paradeda Michele Tedesco Hubertus V.M.Hamelers Lluis Bañeras M.Dolors Balaguer SebastiàPuig Paolo Dessì Institute of the Environment University of Girona.Campus MontiliviCarrer Maria Aurélia Capmany 69E-17003GironaSpain Molecular microbial Ecology Group Institute of Aquatic EcologyUniversity of GironaMaria Aurelia Capmany 4017003GironaSpain Wetsus European Centre of Excellence for Sustainable Water TechnologyOostergoweg 98911MALeeuwardenthe Netherlands

microbial electrosynthesis(MES)is a promising carbon utilization technology,but the low-value products(i.e.,acetate or methane)and the high electric power demand hinder its industrial *** this study,electrically efficient MES cells with a low ohmic resistance of 15.7 mU m^(2)were operated galvanostatically in fed-batch mode,alternating periods of high CO_(2)and H2 *** promoted acetic acid and ethanol production,ultimately triggering selective(78%on a carbon basis)butyric acid production via chain *** average production rate of 14.5 g m^(-2)d^(-1)was obtained at an applied current of 1.0 or 1.5 mA cm^(-2),being Megasphaera *** key chain elongating *** a second cell with the catholyte containing the enriched community resulted in butyric acid production at the same rate as the previous cell,but the lag phase was reduced by 82%.Furthermore,interrupting the CO_(2)feeding and setting a constant pH2 of 1.7e1.8 atm in the cathode compartment triggered solventogenic butanol production at a pH below *** efficient cell design resulted in average cell voltages of 2.6e2.8 V and a remarkably low electric energy requirement of 34.6 kWhel kg1 of butyric acid produced,despite coulombic efficiencies being restricted to 45%due to the cross-over of O_(2)and H2 through the *** conclusion,this study revealed the optimal operating conditions to achieve energy-efficient butyric acid production from CO_(2)and suggested a strategy to further upgrade it to valuable butanol.

关键词： Biocathode Bioelectrochemical system Chain elongation Hydrogen partial pressure Megasphaera

Rearranged 19-nor-7,8-seco-labdane diterpenoids and Diels-Alder cycloadducts from the Chinese liverwort Pallavicinia ambigua:Structural elucidation,photoinduced rearrangement,and cytotoxic activity

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Chinese Chemical Letters 2024年第3期35卷 415-418页

作者： Chunyang Zhang Yuelan Li Zhaojun Chu Shuangzhi Yuan Yanan Qiao Jiaozhen Zhang Lin Li Yueqing Zhang Ruifeng Tian Yajie Tang Hongxiang Lou Department of Natural Products Chemistry Key Lab of Chemical Biology(MOE)School of Pharmaceutical SciencesShandong UniversityJi'nan 250012China State Key Laboratory of microbial Technology Shandong UniversityQingdao 266237China

Two distinctive rearranged 19-nor-7,8-seco-labdane diterpenoids(1 and 2)with a novel tetracyclo[5.***.1.0^(2,5.)0^(4,10)]decane skeleton,a derivative of the open tetrahydrofuran ring(7),three dimeric compounds(8-10),and four revised homologs(3-6)were obtained from Chinese liverwort Pallavicinia *** structures were identified via combined analysis of their spectroscopic data,single-crystal X-ray diffraction patterns,and ECD *** light-driven conversion of compound 5 to compounds 1-4 demonstrated that photochemically induced postmodification involved in biosynthesis is an important way to diversify natural structures.A preliminary cytotoxicity assay revealed that compound 5 showed significant inhibition in the human prostate cancer(PC-3)cell line via an apoptotic pathway.

关键词： Liverwort Pallavicinia ambigua 19-nor-7 8-seco-Labdan diterpenoid Photoinduced rearrangement Cytotoxic activity

Mycorrhizal fungi mitigate nitrogen losses of an experimental grassland by facilitating plant uptake and soil microbial immobilization

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Pedosphere 2024年第2期34卷 399-410页

作者： Yangyang JIA Marcel G.A.VAN DER HEIJDEN Alain Y.VALZANO-HELD Markus JOCHER Florian WALDER Postdoctoral Mobile Station of Ecology College of Ecology and EnvironmentXinjiang UniversityÜrümqi 830046China Research Group Plant-Soil Interactions AgroscopeZürich 8046Switzerland Research Group Climate and Agriculture AgroscopeZürich 8046Switzerland Department of Plant and microbial Biology University of ZürichZürich 8008Switzerland Research Group Soil Quality and Soil Use AgroscopeZürich 8046Switzerland

Nitrogen(N)is one of the most limited nutrients of terrestrial ecosystems,whose losses are prevented in tightly coupled cycles in finely tuned *** change-induced N enrichment through atmospheric deposition and application of vast amounts of fertilizer are now challenging the terrestrial N *** mycorrhizal fungi(AMF)are known drivers of plant-soil nutrient fluxes,but a comprehensive assessment of AMF involvement in N cycling under global change is still ***,we simulated N enrichment by fertilization(low/high)in experimental grassland microcosms under greenhouse conditions in the presence or absence of AMF and continuously monitored different N pathways over nine *** found that high N enrichment by fertilization decreased the relative abundance of legumes and the plant species dominating the plant community changed from grasses to forbs in the presence of AMF,based on aboveground *** presence of AMF always maintained plant N:phosphorus(P)ratios between 14 and 16,no matter how the soil N availability *** in plant N:P ratios due to the increased plant N and P uptake might thus be a primary pathway of AMF altering plant community ***,we constructed a comprehensive picture of AMF’s role in N cycling,highlighting that AMF reduced N losses primarily by mitigating N leaching,while N_(2)O emissions played a marginal *** mycorrhizal fungi reduced N_(2)O emissions directly through the promotion of N_(2)O-consuming *** underlying mechanism for reducing N leaching is mainly the AMF-mediated improved nutrient uptake and AMF-associated microbial *** results indicate that synergies between AMF and other soil microorganisms cannot be ignored in N cycling and that the integral role of AMF in N cycling terrestrial ecosystems can buffer the upcoming global changes.

关键词： N cycling N enrichment N uptake N:P ratio plant community structure symbiotic soil fungi

Insertion sequence transposition activates antimycobacteriophage immunity through an Isr2-silenced lipid metabolism gene island

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mLife 2024年第1期3卷 87-100页

作者： Yakun Li Yuyun Wei Xiao Guo Xiaohui Li Lining Lu Lihua Hu Zheng-Guo He State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources Guangxi Research Center for Microbial and Enzyme Engineering TechnologyCollege of Life Scienceand TechnologyGuangxi UniversityNanningChina

Insertion sequences(ISs)exist widely in bacterial genomes,but their roles in the evolution of bacterial antiphage defense remain to be ***,we report that,under the pressure of phage infection,the IS1o96 transposition of Mycobacterium smegmatis into the Isr2 gene can occur at high frequencies,which endows the mutant mycobacterium with a broad-spectrum antiphage ***2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism-related *** complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium,thus defending against phage ***,a phage that has evolved mutations in two tail-filament genes can re-escape from the Isr2 inactivation-triggered host *** study uncovered a new signaling pathway for activating antimycobacteriophage immunity by Is transposition and provided insight into the natural evolution of bacterial antiphage defense.

关键词： antiphage defense bacteriophage gene island insertion sequence mycobacteria

Rice stripe mosaic virus hijacks rice heading‐related gene to promote the overwintering of its insect vector

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Journal of Integrative Plant Biology 2024年第9期66卷 2000-2016页

作者： Siping Chen Xinyi Zhong Zhiyi Wang Biao Chen Xiuqin Huang Sipei Xu Xin Yang Guohui Zhou Tong Zhang Guangdong Province Key Laboratory of microbial Signals and Disease Control College of Plant ProtectionSouth China Agricultural UniversityGuangzhou 510642China State Key Laboratory of Green Pesticide South China Agricultural UniversityGuangzhou 510642China

Rice stripe mosaic virus(RSMV)is an emerging pathogen which significantly reduces rice yields in the southern region of *** is transmitted by the leafhopper Recilia dorsalis,which overwinters in rice *** field investigations revealed that RSMV infection causes delayed rice heading,resulting in a large number of green diseased plants remaining in winter rice *** creates a favorable environment for leafhoppers and viruses to overwinter,potentially contributing to the rapid spread and epidemic of the ***,we explored the mechanism by which RSMV manipulates the developmental processes of the rice plant.A rice heading‐related E3 ubiquitin ligase,Heading date Associated Factor 1(HAF1),was found to be hijacked by the RSMV‐encoded *** impairment of HAF1 function affects the ubiquitination and degradation of downstream proteins,HEADING DATE 1 and EARLY FLOWERING3,leading to a delay in rice *** results provide new insights into the development regulation‐based molecular interactions between virus and plant,and highlights the importance of understanding virus‐vector‐plant tripartite interactions for effective disease management strategies.

关键词： HAF1 heading leafhoppers overwintering RSMV

Wheat zinc finger protein TaZF interacts with both the powdery mildew AvrPm2 protein and the corresponding wheat Pm2a immune receptor

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Plant Communications 2024年第5期5卷 25-41页

作者： Beatrice Manser Helen Zbinden Gerhard Herren Joel Steger Jonatan Isaksson Stephanie Braunlich Thomas Wicker Beat Keller Department of Plant and microbial Biology University of ZurichZollikerstrasse 1078008 ZurichSwitzerland Agroscope Route de Duillier 501260 NyonSwitzerland BIOREBA AG Christoph Merian-Ring 74153 ReinachSwitzerland

Plant defense responses to pathogens are induced after direct or indirect perception of effector proteins or their activity on host *** fungal–plant interactions,relatively little is known about whether,in addi-tion to avirulence effectors and immune receptors,other proteins contribute to specific *** nucleotide-binding leucine-rich repeat(NLR)immune receptor Pm2a in wheat recognizes the fungal pow-dery mildew effector *** found that the predicted wheat zincfinger TaZF interacts with both the fungal avirulence protein AvrPm2 and the wheat NLR *** further demonstrated that the virulent AvrPm2-H2 variant does not interact with *** silencing in wheat resulted in a reduction but not a loss of Pm2a-mediated powdery mildew *** studies showed that the leucine-rich repeat domain of Pm2a is the mediator of the interaction with *** recruits both Pm2a and AvrPm2 from the cytosol to the nucleus,resulting in nuclear localization of Pm2a,TaZF,and AvrPm2 in *** propose that TaZF acts as a facilitator of Pm2a-dependent AvrPm2 effector *** highlight the importance of identifying effector host targets for characterization of NLR-mediated effector recognition.

关键词： plant immunity plant-fungal interactions pathogen effectors nucleotide-binding leucine-rich repeat immune receptor NLR wheat powdery mildew