[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophor...[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophores were isolated and screened from the roots of the plant Saposhnikovia divaricata(Trucz.)Schischk.The siderophore-producing capability was confirmed through qualitative detection and gene cluster analysis.[Results]The screened endophytic bacterium PB-2 belonged to the genus Paenibacillus sp.and could produce catechol-type or carboxylate-type siderophores.When cultured in MKB medium with 15 g/L glycerol as the carbon source and 6 g/L glycine as the nitrogen source for 3 d,the strain exhibited efficient siderophore secretion.Appropriate concentrations of Fe^(3+),Co^(2+),Cu^(2+)and Al^(3+)promoted siderophore production,with 15μmol/L Fe^(3+)being the most effective.Under the combined influences of siderophores,volatile compounds and other factors,strain PB-2 altered the root morphology of mulberry seedlings and increased their biomass.The primary root length decreased by 9.15%,while the number and length of root hairs increased by 37.93%and 16.37%,respectively,and the total biomass increased by 10.26%,all showing significant differences(P<0.05).Additionally,strain PB-2 enhanced the activities of defense-related enzymes in mulberry seedling leaves.The activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly(P<0.05)by 247.27%and 189.47%,respectively,compared with the control group.The activities of phenylalanine ammonialyase(PAL)and polyphenol oxidase(PPO)also showed varying degrees of increase.[Conclusions]This study provided a theoretical basis for rational utilization of endophytic growth-promoting strains secreting siderophores in the sustainable development of agriculture.展开更多
[Objective] With a strain of endophytic antagonistic bacteria with good disease control efficacy in pot as trial material,the paper was to explore the antagonistic mechanism of siderophore against Fusarium oxysporum.[...[Objective] With a strain of endophytic antagonistic bacteria with good disease control efficacy in pot as trial material,the paper was to explore the antagonistic mechanism of siderophore against Fusarium oxysporum.[Method] Whether the strain produced siderophore and its fluorescent property was judged by MSA（Modified Sugar-Aspartic acid） plate.The siderophore activity of strains in liquid MSA medium was determined through the absorbance values at particular wavelength.The inhibition effects of it siderophore against F.oxysporum under different concentrations of Fe3＋ were compared.Then the strain was preliminarily identified based on morphological,physiological and biochemical characteristics [Result] The fluorescent siderophore produced by the endophytic bacteria in MSA medium had a strong inhibition effect against F.oxysporum.With the increasing concentration of Fe3＋,the inhibition effect against the pathogen weakened.The preliminary analysis showed these strains belonged to Bacillus.[Conclusion] Bacillus could compete the absorption of Fe3＋ by secreting siderophore to inhibit the growth of F.oxysporum.展开更多
Iron is an essential but excessively toxic nutrient. Although iron is rich in nature, the acquisition of iron is a challenge to life. Its solubility is very low because it is mostly in the form of oxidation or hydroxi...Iron is an essential but excessively toxic nutrient. Although iron is rich in nature, the acquisition of iron is a challenge to life. Its solubility is very low because it is mostly in the form of oxidation or hydroxide. In order to overcome this, microorganisms have evolved a variety of iron absorption pathways, the most important of which is the siderophore-dependent iron absorption pathway. Both bacteria and fungi require specific siderophore esterases to encourage the release of iron within the cell. A deeper understanding of siderophore esterases is crucial for the development of new antibacterial and antifungal diagnostic and therapeutic approaches. There have been many recent studies on anti-infectives via siderophore antibiotic couplers in which siderophore esterases have also played an important role, and in this review, we provide an overview of several of the more common iron carriers as well as siderophore esterases in terms of structure as well as function.展开更多
In view of the fact that siderophores from microorganisms in different environments have received much attention in recent years because of their potential applications and diverse physiological functions, this review...In view of the fact that siderophores from microorganisms in different environments have received much attention in recent years because of their potential applications and diverse physiological functions, this review deals with side rophore producing marine microorganisms and the detection, chemical structure and potential applications of siderophores.展开更多
Mycosphazine A(1), a new iron(Ⅲ) chelator of coprogen-type siderophore, and mycosphamide A(2), a new cyclic amide benzoate, together with six known aryl amides(3-8), were isolated from the fermentation broth of the d...Mycosphazine A(1), a new iron(Ⅲ) chelator of coprogen-type siderophore, and mycosphamide A(2), a new cyclic amide benzoate, together with six known aryl amides(3-8), were isolated from the fermentation broth of the deep-sea-derived fungus Mycosphaerella sp. SCSIO z059. Alkaline hydrolysis of 1 afforded a new epimer of dimerum acid, mycosphazine B(1 a), and a new bi-fusarinine-type siderophore, mycosphazine C(1 b). The planar structures of the new compounds were elucidated by extensive spectroscopic data analysis. The absolute configurations of amino acid residues in 1 a and 1 b were determined by acid hydrolysis. And the absolute configuration of 2 was established by quantum chemical calculations of the electronic circular dichroism(ECD) spectra. Compound 1 is the first siderophore-Fe(Ⅲ) chelator incorporating both L-ornithine and D-ornithine unites. Compounds 3-8 were reported as natural products for the first time, and the 1 H and 13 C NMR data of 6 and 8 were assigned for the first time. Compounds 1 and 1 a could greatly promote the biofilm formation of bacterium Bacillus amyloliquefaciens with the rate of about 249% and 524% at concentration of 100 μg·mL-1, respectively.展开更多
A significant challenge in bacterial detection is the identification of viable bacteria over debris, specifically post decontamination. Of increasing concern are antibiotic resistant strains that require accurate and ...A significant challenge in bacterial detection is the identification of viable bacteria over debris, specifically post decontamination. Of increasing concern are antibiotic resistant strains that require accurate and rapid post decontamination analysis. Current strategies are fraught with disadvantages and most of them are not selective for viable bacteria. However, bacteria are critically dependent upon iron sequestration, synthesizing and releasing siderophores (SDPs) to tightly bind iron, with the subsequent uptake of iron bound SDPs. This is a highly conserved process that occurs only in intact bacteria. Herein we report a facile method to use bacterial SDPs to selectively and rapidly identify only viable bacteria in complex matrices, and discriminate them from their dead counterparts. Desferrioxamine B (Desf B) tethered to a glass slide is used to specifically capture viable bacteria from a mixture of viable and dead Escherichia coli, as demonstrated by fluorescence microscopy. We re- port both direct conjugation of Desf B on thin-film-coated glass slides as well as biotin-streptavidin conjugation strategies, both of which are successful in the said goal. We have analyzed the density of images obtained upon fluorescence staining using edge detection with a Canny edge detector. This novel application of a software analysis tool originally developed for satellite imaging to biological staining allows for accurate quantitation of observed data.展开更多
This chemical study reports a novel siderophore-like compound,β-cyclopiazonic acid(1,β-CPA)extracted from marine fungus Aspergillus flavus.The chemical structure ofβ-CPA was elucidated by a combination of extensive...This chemical study reports a novel siderophore-like compound,β-cyclopiazonic acid(1,β-CPA)extracted from marine fungus Aspergillus flavus.The chemical structure ofβ-CPA was elucidated by a combination of extensive spectroscopic analyses and TDDFT-ECD calculations.The iron-binding ability and CAS assays demonstrate thatβ-CPA is a novel siderophore that features a different chemical structure from those of traditional siderophores.Theβ-CPA has no obvious influence on the growth of bacterium Pseudomonas aeruginosa PAO1.However,its iron chelator could promote the growth of P.aeruginosa PAO1,suggesting that P.aeruginosa employed siderophores to sequester iron,which is vital for their survival.The study provides the physiochemical evaluation ofβ-CPA,an unusual skeletonstructure siderophore,which for the first time,was proven to have the ability to bind iron and affect P.aeruginosa growth.This new discovery of siderophore provides an opportunity for developing novel anti-P.aeruginosa drugs.展开更多
Ulcerative colitis(UC)and Crohn’s disease(CD)are chronic inflammatory bowel diseases(IBDs)with largely unclear etiologies and complex pathogeneses.The pathogenesis of UC has been linked to an imbalance in the gut mic...Ulcerative colitis(UC)and Crohn’s disease(CD)are chronic inflammatory bowel diseases(IBDs)with largely unclear etiologies and complex pathogeneses.The pathogenesis of UC has been linked to an imbalance in the gut microbiota,including in the prevalence of Enterobacteriaceae,especially pathogenic Escherichia coli(E.coli).[1]The UC diagnosis and assessment primarily rely on colonoscopy and mucosal biopsy pathology,which are limited by their invasiveness,constraints on medical resources,and potential risks and complications.Several biomarkers,such as serum C-reactive protein(CRP),fecal calprotectin,and fecal lactoferrin,are currently recommended for assessing UC disease activity.However,these markers are primarily inflammation-related factors produced by the host,not specific to IBD,and are influenced by other inflammatory states.Microbiome-related biomarkers are used as direct indicators of the gut microecosystem and have considerable potential for disease assessment and therapeutic guidance in IBD.However,current analyses of gut microbiota,such as 16S rRNA or metagenomic sequencing,are often time-consuming and costly.Siderophore,a low-molecularweight protein secreted extracellularly to chelate ferric iron,is a crucial virulence factor in iron acquisition of bacteria and fungi.The presence of siderophores can indirectly reflect bacterial abundance and activity.[2]展开更多
Iron is a critical yet limited nutrient for microbial growth.To scavenge iron,most microbes produce siderophores—diverse small molecules with high iron affinities.Different siderophores are specifically recognized an...Iron is a critical yet limited nutrient for microbial growth.To scavenge iron,most microbes produce siderophores—diverse small molecules with high iron affinities.Different siderophores are specifically recognized and uptaken by corresponding recognizers,enabling targeted interventions and intriguing cheater-producer dynamics.We propose constructing a comprehensive iron interaction network,or“iron-net”,across the microbial world.Such a network offers the potential for precise manipulation of the microbiota,with conceivable applications in medicine,agriculture,and industry as well as advancing microbial ecologyandevolution theories.Previously,our successful construction of an iron-net in the Pseudomonas genus demonstrated the feasibility of coevolution-inspired digital siderophore-typing.Enhanced by machine learning techniques and expanding sequencing data,forging such an iron-net calls for multidisciplinary collaborations and holds significant promise in addressing critical challenges in microbial communities.展开更多
Tuberculosis remains a public health threat of global proportions.Iron is a scarce resource indispensable to both host and pathogen during infection with Mycobacterium tuberculosis,the causative agent of tuberculosis....Tuberculosis remains a public health threat of global proportions.Iron is a scarce resource indispensable to both host and pathogen during infection with Mycobacterium tuberculosis,the causative agent of tuberculosis.Siderophores are critical molecules for iron acquisition under iron-limiting conditions and,as a very efficient pathogen,M.tuberculosis has evolved elaborate siderophores knowledge of which is being intensively translated into clinical practice.This paper summarizes the structures,types and physiological functions of Mycobacterium siderophores with emphasis on siderophore-inspired design of drugs and drug delivery vehicles.展开更多
The biosynthetic potential of actinobacteria to produce novel natural products is still regarded as immense.In this paper,we correlated a cryptic biosynthetic gene cluster to chemical molecules by genome mining and ch...The biosynthetic potential of actinobacteria to produce novel natural products is still regarded as immense.In this paper,we correlated a cryptic biosynthetic gene cluster to chemical molecules by genome mining and chemical analyses,leading to the discovery of a new group of catecholate-hydroxamate siderophores,nobachelins,from Nocardiopsis baichengensis DSM 44845.Nobachelin biosynthesis genes are conserved in several bacteria from the family Nocardiopsidaceae.Structurally,nobachelins feature fatty-acylated hydroxy-ornithine and a rare chlorinated catecholate group.Intriguingly,nobachelins rescued Caenorhabditis elegans from Pseudomonas aeruginosa-mediated killing.展开更多
Iron is essential for bacterial survival,and most bacteria capture iron by producing siderophores.Burkholde-riales bacteria produce various types of bioactive secondary metabolites,such as ornibactin and malleobactin ...Iron is essential for bacterial survival,and most bacteria capture iron by producing siderophores.Burkholde-riales bacteria produce various types of bioactive secondary metabolites,such as ornibactin and malleobactin siderophores.In this study,the genome analysis of Burkholderiales genomes showed a putative novel siderophore gene cluster crb,which is highly similar to the ornibactin and malleobactin gene clusters but does not have pvdF,a gene encoding a formyltransferase for N-δ-hydroxy-ornithine formylation.Establishing the bacteriophage recom-binase Redγ-Redδβ7029 mediated genome editing system in a non-model Burkholderiales strain Paraburkholderia caribensis CICC 10960 allowed the rapid identification of the products of crb gene cluster,caribactins A-F(1-6).Caribactins contain a special amino acid residue N-δ-hydroxy-N-δ-acetylornithine(haOrn),which differs from the counterpart N-δ-hydroxy-N-δ-formylornithine(hOrn)in ornibactin and malleobactin,owing to the absence of pvdF.Gene inactivation showed that the acetylation of hOrn is catalyzed by CrbK,whose homologs proba-bly not be involved in the biosynthesis of ornibactin and malleobactin,showing possible evolutionary clues of these siderophore biosynthetic pathways from different genera.Caribactins promote biofilm production and en-hance swarming and swimming abilities,suggesting that they may play crucial roles in biofilm formation.This study also revealed that recombineering has the capability to mine novel secondary metabolites from non-model Burkholderiales species.展开更多
The adenosine 5'-triphosphate(ATP)-binding cassette(ABC)transporter,IrtAB,plays a vital role in the replication and viability of Mycobacterium tuberculosis(Mtb),where its function is to import iron-loaded sideroph...The adenosine 5'-triphosphate(ATP)-binding cassette(ABC)transporter,IrtAB,plays a vital role in the replication and viability of Mycobacterium tuberculosis(Mtb),where its function is to import iron-loaded siderophores.Unusually,it adopts the canonical type IV exporter fold.Herein,we report the structure of unliganded Mtb IrtAB and its structure in complex with ATP,ADP,or ATP analogue(AMP-PNP)at resolutions ranging from 2.8 to 3.5Å.The structure of IrtAB bound ATP-Mg2+shows a“head-to-tail”dimer of nucleotide-binding domains(NBDs),a closed amphipathic cavity within the transmembrane domains(TMDs),and a metal ion liganded to three histidine residues of IrtA in the cavity.Cryo-electron microscopy(Cryo-EM)structures and ATP hydrolysis assays show that the NBD of IrtA has a higher affinity for nucleotides and increased ATPase activity compared with IrtB.Moreover,the metal ion located in the TM region of IrtA is critical for the stabilization of the conformation of IrtAB during the transport cycle.This study provides a structural basis to explain the ATP-driven conformational changes that occur in IrtAB.展开更多
This study highlights the production and characterization of siderophore from probiotic bacteria,aiming to evaluate its suitability as a carrier to treat iron deficiency anemia.Organisms were previously isolated from ...This study highlights the production and characterization of siderophore from probiotic bacteria,aiming to evaluate its suitability as a carrier to treat iron deficiency anemia.Organisms were previously isolated from Chhurpi(Himalayan traditional fermented food)and their probiotic characteristics were reported.Among the,Bacillus subtilis L9 that produced catecholate and Pediococcus pentosaceus BAC L7 synthesized hydroxymate and catecholate type of siderophore.After optimization(pH 6.0,100 rpm agitation speed and 15%inoculums volume)B.subtilis L9 and P.pentosaceus BAC L7 produced 89 and 73%siderophore unit respectively,after 72 h of incubation at simulated gastro-intestinal condition.Owing to better siderophore production and spore forming capability B.subtilis L9 was selected and physico-chemical characteristics of its siderophore were studied by FTIR,NMR and mass spectrometric analysis.The purified siderophore(2,3-dihydroxybenzoyl glycine)from B.subtilis L9 exhibited a high iron scavenging activity(89.76%).The study was penlights the exploration of probiotic microorganism present in the indigenous fermented food and their capability to biosynthesize siderophore that could be an effective therapeutic aid for maximum absorption of dietary iron and alleviation anemia like micronutrient deficiency diseases as well as to combat hypoxia among the high altitude residents.展开更多
This present study identifies endophytic bacteria from Linum usitatissimum with multidimensional plant growth-promoting attributes,positioning them as ecological engineers for sustainable agriculture.Plant growthpromo...This present study identifies endophytic bacteria from Linum usitatissimum with multidimensional plant growth-promoting attributes,positioning them as ecological engineers for sustainable agriculture.Plant growthpromoting bacteria(PGPB)are present in symbiotic associations with plants or rhizosphere.These microbes enhance crop productivity and resilience under different environmental conditions.Endophytes are a type of PGPB that inhabit inside plant tissues and contribute to plant growth by phytohormone production,phosphate solubilisation,zinc solubilisation,siderophore production,ammonia production,nitrogen fixation,stress tolerance,and biocontrol mechanisms.Twelve bacterial strains were isolated from Linum usitatissimum exhibiting plant growth-promoting attributes such as ammonia and indole-3-acetic acid(IAA)production,siderophore synthesis,phosphate solubilisation,and extracellular enzyme synthesis.The isolated endophytes were also assessed for different enzymatic activities such as;cellulase,pectinase,xylanase,amylase,and gelatinase,which contribute to development of a symbiotic relationship and are crucial for the degradation of plant cell wall components The most efficient endophytes identified in the present study were Pseudomonas sp.strain JL-1(ESL1)and Staphylococcus sciuri(ESL2),both of which displayed strong plant growth-promoting potential.ESL1 and ESL2 demonstrated promising plant growth-promoting characteristics and cellulase,pectinase,xylanase,amylase,and gelatinase,activity.ESL2(Staphylococcus sciuri)enhanced nutrient cycling(phosphate solubilisation:196-209μg/ml;siderophores:68-71%)and stress tolerance(IAA:11-12μg/ml),reducing reliance on synthetic inputs.By integrating flax microbiomes into agro-ecosystems,we demonstrate a scalable approach to reconcile crop productivity with soil biodiversity conservation.These results demonstrate the potentiality of these endophytic microbes in sustainable agriculture,environmental management,and microbial biotechnology.Further studies on their metabolic pathways may expand their applications in bioremediation and plant-microbe interactions.展开更多
Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of...Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of saline stress in crops.This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria(PGPRs),isolated from the rhizosphere of halophile plants,for the growth,Na^+/K^+balance,ethylene emission,and gene expression of wheat seedlings{Triticum aestivum L.)grown under saline conditions(100 mmol L^-1 NaCl)for 14 d.A total of 118 isolates obtained from saline soils of the deserts of Iran were tested for their capacity as PGPRs.Out of the 118 isolates,17 could solubilize phosphate(Ca3(P〇4)2),5 could produce siderophores,and 16 could synthesize indole-3-acetic acid.Additionally,PGPRs were also evaluated for aminocyclopropane-l-carboxylate deaminase activity.A pot experiment was conducted to evaluate the ability of 28 PGPR isolates to promote growth,regulate Na^+/K^+balance,and decrease ethylene emissions in plants.The most efficient PGPRs were Arthrobacter aurescens.Bacillus atrophaeus,Enterobacter ashuriae,and Pseudomonas fluorescens.Gene expression analysis revealed the up-regulation of H^+-PPase,HKT1,NHX7,CAT,and APX expression in roots of Enterobacter-inocuVdied salt-stressed plants.Salt-tolerant rhizobacteria exhibiting plant growth-promoting traits can facilitate the growth of wheat plants under saline conditions.Our results indicate that the isolation of these bacteria may be useful for formulating new inoculants to improve wheat cropping systems in saline soils.展开更多
Mutant J61321 with enhanced siderophore production of Alteromonas aurantia AI8 was obtained after a series of chemical-physical mutageneses. It was found that the antibacterial activity against Vibrio anguillarum W-1 ...Mutant J61321 with enhanced siderophore production of Alteromonas aurantia AI8 was obtained after a series of chemical-physical mutageneses. It was found that the antibacterial activity against Vibrio anguillarum W-1 and siderophore production of the mutant were higher than those by the original strain A 18 which had been used in mariculture. The results of the specific assay（Csaky and Arnow methods） of siderophore showed that the sidrophore with hydroxamate group was produced by mutant J61321 and the original strain A 18, respectively, while the siderophore with catechol group was yielded by strain W-1 （Aibrio anguillarum）. Meanwhile, the siderophore yield, antibacterial activity and anti-chelator activity of strain J61321 were higher than those of its parent strain A 18.展开更多
We reported herein the synthesis and antibacterial activity evaluation of two oxazolidinone-deferasirox conjugates with different linkers that were designed based on the“Trojan horse”strategy.The conjugates could co...We reported herein the synthesis and antibacterial activity evaluation of two oxazolidinone-deferasirox conjugates with different linkers that were designed based on the“Trojan horse”strategy.The conjugates could combine with Fe^(3+)ions as the deferasirox.However,both conjugates were inactive against tested bacteria,including S.aureus,E.coli,A.baumannii,and P.aeruginosa.The results suggested that the synthesized iron chelator deferasirox was not suitable as a siderophore of the bacteria to transport the antibiotic,or the coupling linker of the synthesized conjugates could not be hydrolyzed to release the oxazolidinone in the cytoplasm.Therefore,the design and synthesis of oxazolidinone-deferasirox conjugates need further exploration.展开更多
Klebsiella pneumoniae is an opportunistic pathogen of medical importance and the capsule and mucoid phenotype in this organism are considered as requisite virulence determinants. A total of 62 clinical samples from AT...Klebsiella pneumoniae is an opportunistic pathogen of medical importance and the capsule and mucoid phenotype in this organism are considered as requisite virulence determinants. A total of 62 clinical samples from ATBUTH were collected and screened for K. pneumoniae. The isolates were identified using standard tests for this organism. The string test was used to detect the mucoid (hypermucoviscous) phenotype and the antimicrobial susceptibility test to 10 antibiotics was carried out with the disk diffusion technique after standardizing inoculum. A K. pneumoniae prevalence of 24% (15/62) was obtained of which 47% (7/15) were mucoid (hypermucoviscous) and 53% (8/15) were non-mucoid. Colonial sizes of the two strains do not reveal any significant differences in growth fitness of the strains. On blood agar, the mucoid and non-mucoid strains had a mean colonial size ± standard deviations of 4.41 ± 0.58 mm and 4.27 ± 0.42 mm respectively. The antibiotic susceptibility rate showed that the mucoid strains compared to the non-mucoid were more resistant to nine out of 10 antibiotics. The mucoid strains were outrightly resistant to augmentin, amoxicillin, septrin, sparfloxacin and perfloxacin. The non-mucoid strains showed no complete resistant to any antibiotic tested but had a higher resistant rate to chloramphenicol only. The Multiple Antibiotic Resistance (MAR) index shows the themucoid strains with a high MAR index range of 0.7 - 1.0 with a median MAR index of 0.8, while the non-mucoid strains had a MAR index of 0.2 - 0.8 with a median MAR index of 0.35. The data suggest that the mucoid phenotype could be associated with extrachromsomal element(s) carrying resistance genes to antibiotics and that these extrachromosomal elements may not harbour resistance determinants to chloramphenicol. Furthermore, the extrachromosomal elements bearing the mucoid phenotype and the resistance elements in the mucoid strains do not significantly impact on the fitness of the cognate strain. Whether these phenotype and resistances that had no fitness cost to the bacterium could significantly affect the virulence of the bacteria in vivo remains to be investigated.展开更多
基金Supported by Doctoral Start-up Fund of Jiangsu University of Science and Technology(1102931901).
文摘[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophores were isolated and screened from the roots of the plant Saposhnikovia divaricata(Trucz.)Schischk.The siderophore-producing capability was confirmed through qualitative detection and gene cluster analysis.[Results]The screened endophytic bacterium PB-2 belonged to the genus Paenibacillus sp.and could produce catechol-type or carboxylate-type siderophores.When cultured in MKB medium with 15 g/L glycerol as the carbon source and 6 g/L glycine as the nitrogen source for 3 d,the strain exhibited efficient siderophore secretion.Appropriate concentrations of Fe^(3+),Co^(2+),Cu^(2+)and Al^(3+)promoted siderophore production,with 15μmol/L Fe^(3+)being the most effective.Under the combined influences of siderophores,volatile compounds and other factors,strain PB-2 altered the root morphology of mulberry seedlings and increased their biomass.The primary root length decreased by 9.15%,while the number and length of root hairs increased by 37.93%and 16.37%,respectively,and the total biomass increased by 10.26%,all showing significant differences(P<0.05).Additionally,strain PB-2 enhanced the activities of defense-related enzymes in mulberry seedling leaves.The activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly(P<0.05)by 247.27%and 189.47%,respectively,compared with the control group.The activities of phenylalanine ammonialyase(PAL)and polyphenol oxidase(PPO)also showed varying degrees of increase.[Conclusions]This study provided a theoretical basis for rational utilization of endophytic growth-promoting strains secreting siderophores in the sustainable development of agriculture.
基金Supported by National Natural Science Foundation of China(30960010 )Principal Fund Key Projects of Tarim University(TDZKZD06001)~~
文摘[Objective] With a strain of endophytic antagonistic bacteria with good disease control efficacy in pot as trial material,the paper was to explore the antagonistic mechanism of siderophore against Fusarium oxysporum.[Method] Whether the strain produced siderophore and its fluorescent property was judged by MSA（Modified Sugar-Aspartic acid） plate.The siderophore activity of strains in liquid MSA medium was determined through the absorbance values at particular wavelength.The inhibition effects of it siderophore against F.oxysporum under different concentrations of Fe3＋ were compared.Then the strain was preliminarily identified based on morphological,physiological and biochemical characteristics [Result] The fluorescent siderophore produced by the endophytic bacteria in MSA medium had a strong inhibition effect against F.oxysporum.With the increasing concentration of Fe3＋,the inhibition effect against the pathogen weakened.The preliminary analysis showed these strains belonged to Bacillus.[Conclusion] Bacillus could compete the absorption of Fe3＋ by secreting siderophore to inhibit the growth of F.oxysporum.
文摘Iron is an essential but excessively toxic nutrient. Although iron is rich in nature, the acquisition of iron is a challenge to life. Its solubility is very low because it is mostly in the form of oxidation or hydroxide. In order to overcome this, microorganisms have evolved a variety of iron absorption pathways, the most important of which is the siderophore-dependent iron absorption pathway. Both bacteria and fungi require specific siderophore esterases to encourage the release of iron within the cell. A deeper understanding of siderophore esterases is crucial for the development of new antibacterial and antifungal diagnostic and therapeutic approaches. There have been many recent studies on anti-infectives via siderophore antibiotic couplers in which siderophore esterases have also played an important role, and in this review, we provide an overview of several of the more common iron carriers as well as siderophore esterases in terms of structure as well as function.
文摘In view of the fact that siderophores from microorganisms in different environments have received much attention in recent years because of their potential applications and diverse physiological functions, this review deals with side rophore producing marine microorganisms and the detection, chemical structure and potential applications of siderophores.
基金the Guangdong Provincial-level Special Funds for Promoting High-quality Economic Development (No. 2020032)Natural science foundation of Guangdong province (No. 2017A030313235)+1 种基金Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(No. GML2019-ZD0406)National Natural Science Foundation of China (No.81673326).
文摘Mycosphazine A(1), a new iron(Ⅲ) chelator of coprogen-type siderophore, and mycosphamide A(2), a new cyclic amide benzoate, together with six known aryl amides(3-8), were isolated from the fermentation broth of the deep-sea-derived fungus Mycosphaerella sp. SCSIO z059. Alkaline hydrolysis of 1 afforded a new epimer of dimerum acid, mycosphazine B(1 a), and a new bi-fusarinine-type siderophore, mycosphazine C(1 b). The planar structures of the new compounds were elucidated by extensive spectroscopic data analysis. The absolute configurations of amino acid residues in 1 a and 1 b were determined by acid hydrolysis. And the absolute configuration of 2 was established by quantum chemical calculations of the electronic circular dichroism(ECD) spectra. Compound 1 is the first siderophore-Fe(Ⅲ) chelator incorporating both L-ornithine and D-ornithine unites. Compounds 3-8 were reported as natural products for the first time, and the 1 H and 13 C NMR data of 6 and 8 were assigned for the first time. Compounds 1 and 1 a could greatly promote the biofilm formation of bacterium Bacillus amyloliquefaciens with the rate of about 249% and 524% at concentration of 100 μg·mL-1, respectively.
文摘A significant challenge in bacterial detection is the identification of viable bacteria over debris, specifically post decontamination. Of increasing concern are antibiotic resistant strains that require accurate and rapid post decontamination analysis. Current strategies are fraught with disadvantages and most of them are not selective for viable bacteria. However, bacteria are critically dependent upon iron sequestration, synthesizing and releasing siderophores (SDPs) to tightly bind iron, with the subsequent uptake of iron bound SDPs. This is a highly conserved process that occurs only in intact bacteria. Herein we report a facile method to use bacterial SDPs to selectively and rapidly identify only viable bacteria in complex matrices, and discriminate them from their dead counterparts. Desferrioxamine B (Desf B) tethered to a glass slide is used to specifically capture viable bacteria from a mixture of viable and dead Escherichia coli, as demonstrated by fluorescence microscopy. We re- port both direct conjugation of Desf B on thin-film-coated glass slides as well as biotin-streptavidin conjugation strategies, both of which are successful in the said goal. We have analyzed the density of images obtained upon fluorescence staining using edge detection with a Canny edge detector. This novel application of a software analysis tool originally developed for satellite imaging to biological staining allows for accurate quantitation of observed data.
基金Supported by the Natural Foundation of Zhejiang Province(No.LGF21H300003)the Key Laboratory of Tropical Marine Ecosystem and Bioresource,Ministry of Natural Resources(No.2021QN03)+2 种基金the Key Research and Development Program of Zhejiang Province(No.2021C03084)the Key Research and Development Program of National Key R&D Program of China(Nos.2018YFC0311003,2017YFE0103100)the High Level Talent Special Support Plan of Zhejiang Province(No.2019R52009).We also gratefully acknowledge platform support from Zhejiang International Sci-Tech Cooperation Base for the Exploitation and Utilization of Nature Product。
文摘This chemical study reports a novel siderophore-like compound,β-cyclopiazonic acid(1,β-CPA)extracted from marine fungus Aspergillus flavus.The chemical structure ofβ-CPA was elucidated by a combination of extensive spectroscopic analyses and TDDFT-ECD calculations.The iron-binding ability and CAS assays demonstrate thatβ-CPA is a novel siderophore that features a different chemical structure from those of traditional siderophores.Theβ-CPA has no obvious influence on the growth of bacterium Pseudomonas aeruginosa PAO1.However,its iron chelator could promote the growth of P.aeruginosa PAO1,suggesting that P.aeruginosa employed siderophores to sequester iron,which is vital for their survival.The study provides the physiochemical evaluation ofβ-CPA,an unusual skeletonstructure siderophore,which for the first time,was proven to have the ability to bind iron and affect P.aeruginosa growth.This new discovery of siderophore provides an opportunity for developing novel anti-P.aeruginosa drugs.
文摘Ulcerative colitis(UC)and Crohn’s disease(CD)are chronic inflammatory bowel diseases(IBDs)with largely unclear etiologies and complex pathogeneses.The pathogenesis of UC has been linked to an imbalance in the gut microbiota,including in the prevalence of Enterobacteriaceae,especially pathogenic Escherichia coli(E.coli).[1]The UC diagnosis and assessment primarily rely on colonoscopy and mucosal biopsy pathology,which are limited by their invasiveness,constraints on medical resources,and potential risks and complications.Several biomarkers,such as serum C-reactive protein(CRP),fecal calprotectin,and fecal lactoferrin,are currently recommended for assessing UC disease activity.However,these markers are primarily inflammation-related factors produced by the host,not specific to IBD,and are influenced by other inflammatory states.Microbiome-related biomarkers are used as direct indicators of the gut microecosystem and have considerable potential for disease assessment and therapeutic guidance in IBD.However,current analyses of gut microbiota,such as 16S rRNA or metagenomic sequencing,are often time-consuming and costly.Siderophore,a low-molecularweight protein secreted extracellularly to chelate ferric iron,is a crucial virulence factor in iron acquisition of bacteria and fungi.The presence of siderophores can indirectly reflect bacterial abundance and activity.[2]
基金The National Natural Science Foundation of China,Grant/Award Numbers:32071255,T2321001the Peking-Tsinghua Center for Life Sciences。
文摘Iron is a critical yet limited nutrient for microbial growth.To scavenge iron,most microbes produce siderophores—diverse small molecules with high iron affinities.Different siderophores are specifically recognized and uptaken by corresponding recognizers,enabling targeted interventions and intriguing cheater-producer dynamics.We propose constructing a comprehensive iron interaction network,or“iron-net”,across the microbial world.Such a network offers the potential for precise manipulation of the microbiota,with conceivable applications in medicine,agriculture,and industry as well as advancing microbial ecologyandevolution theories.Previously,our successful construction of an iron-net in the Pseudomonas genus demonstrated the feasibility of coevolution-inspired digital siderophore-typing.Enhanced by machine learning techniques and expanding sequencing data,forging such an iron-net calls for multidisciplinary collaborations and holds significant promise in addressing critical challenges in microbial communities.
基金supported by the National Key Infectious Disease Project(No.2008ZX10003-006)National Natural Science Foundation(Grant No.81071316)+2 种基金Excellent PhD Thesis Fellowship of Southwest University(Nos.kb2009010 and ky2009009)the Fundamental Research Fund for the Central Universities(No.XDJK2009A003)Natural Science Foundation Project of CQ CSTC(No.2010BB5002)。
文摘Tuberculosis remains a public health threat of global proportions.Iron is a scarce resource indispensable to both host and pathogen during infection with Mycobacterium tuberculosis,the causative agent of tuberculosis.Siderophores are critical molecules for iron acquisition under iron-limiting conditions and,as a very efficient pathogen,M.tuberculosis has evolved elaborate siderophores knowledge of which is being intensively translated into clinical practice.This paper summarizes the structures,types and physiological functions of Mycobacterium siderophores with emphasis on siderophore-inspired design of drugs and drug delivery vehicles.
基金support from the Helmholtz International Lab(InterLabs0007)Yuhao Ren acknowledges the support from the International Postdoctoral Exchange Fellowship Program(ZD202125)between Helmholtz AssociationGermany and the Office of China Postdoc Council(OCPC),China.
文摘The biosynthetic potential of actinobacteria to produce novel natural products is still regarded as immense.In this paper,we correlated a cryptic biosynthetic gene cluster to chemical molecules by genome mining and chemical analyses,leading to the discovery of a new group of catecholate-hydroxamate siderophores,nobachelins,from Nocardiopsis baichengensis DSM 44845.Nobachelin biosynthesis genes are conserved in several bacteria from the family Nocardiopsidaceae.Structurally,nobachelins feature fatty-acylated hydroxy-ornithine and a rare chlorinated catecholate group.Intriguingly,nobachelins rescued Caenorhabditis elegans from Pseudomonas aeruginosa-mediated killing.
基金supported by the National Key R&D Program of China(2019YFA0905700)National Natural Science Foundation of China(32070060).
文摘Iron is essential for bacterial survival,and most bacteria capture iron by producing siderophores.Burkholde-riales bacteria produce various types of bioactive secondary metabolites,such as ornibactin and malleobactin siderophores.In this study,the genome analysis of Burkholderiales genomes showed a putative novel siderophore gene cluster crb,which is highly similar to the ornibactin and malleobactin gene clusters but does not have pvdF,a gene encoding a formyltransferase for N-δ-hydroxy-ornithine formylation.Establishing the bacteriophage recom-binase Redγ-Redδβ7029 mediated genome editing system in a non-model Burkholderiales strain Paraburkholderia caribensis CICC 10960 allowed the rapid identification of the products of crb gene cluster,caribactins A-F(1-6).Caribactins contain a special amino acid residue N-δ-hydroxy-N-δ-acetylornithine(haOrn),which differs from the counterpart N-δ-hydroxy-N-δ-formylornithine(hOrn)in ornibactin and malleobactin,owing to the absence of pvdF.Gene inactivation showed that the acetylation of hOrn is catalyzed by CrbK,whose homologs proba-bly not be involved in the biosynthesis of ornibactin and malleobactin,showing possible evolutionary clues of these siderophore biosynthetic pathways from different genera.Caribactins promote biofilm production and en-hance swarming and swimming abilities,suggesting that they may play crucial roles in biofilm formation.This study also revealed that recombineering has the capability to mine novel secondary metabolites from non-model Burkholderiales species.
基金supported by grants from the National Key Research and Development Program of China(Grant No.2022YFC2302900)the National Natural Science Foundation of China(Grant No.32171217 to B.Z.)+5 种基金Shanghai Sailing Program(Grant No.21YF1429700 to B.Z.)Young Elite Scientists Sponsorship Program by CAST(Grant No.2021QNRC001)the Lingang Laboratory(Grant No.LG202101-01-08)Shanghai Municipal Science and Technology Major Project(Grant No.ZD2021CY001)Science and Technology Commission of Shanghai Municipality(Grant No.20XD1422900 to H.Y.)the Shanghai Frontiers Science Center for Biomacromolecules and Precision Medicine,Shanghaitech University.
文摘The adenosine 5'-triphosphate(ATP)-binding cassette(ABC)transporter,IrtAB,plays a vital role in the replication and viability of Mycobacterium tuberculosis(Mtb),where its function is to import iron-loaded siderophores.Unusually,it adopts the canonical type IV exporter fold.Herein,we report the structure of unliganded Mtb IrtAB and its structure in complex with ATP,ADP,or ATP analogue(AMP-PNP)at resolutions ranging from 2.8 to 3.5Å.The structure of IrtAB bound ATP-Mg2+shows a“head-to-tail”dimer of nucleotide-binding domains(NBDs),a closed amphipathic cavity within the transmembrane domains(TMDs),and a metal ion liganded to three histidine residues of IrtA in the cavity.Cryo-electron microscopy(Cryo-EM)structures and ATP hydrolysis assays show that the NBD of IrtA has a higher affinity for nucleotides and increased ATPase activity compared with IrtB.Moreover,the metal ion located in the TM region of IrtA is critical for the stabilization of the conformation of IrtAB during the transport cycle.This study provides a structural basis to explain the ATP-driven conformational changes that occur in IrtAB.
文摘This study highlights the production and characterization of siderophore from probiotic bacteria,aiming to evaluate its suitability as a carrier to treat iron deficiency anemia.Organisms were previously isolated from Chhurpi(Himalayan traditional fermented food)and their probiotic characteristics were reported.Among the,Bacillus subtilis L9 that produced catecholate and Pediococcus pentosaceus BAC L7 synthesized hydroxymate and catecholate type of siderophore.After optimization(pH 6.0,100 rpm agitation speed and 15%inoculums volume)B.subtilis L9 and P.pentosaceus BAC L7 produced 89 and 73%siderophore unit respectively,after 72 h of incubation at simulated gastro-intestinal condition.Owing to better siderophore production and spore forming capability B.subtilis L9 was selected and physico-chemical characteristics of its siderophore were studied by FTIR,NMR and mass spectrometric analysis.The purified siderophore(2,3-dihydroxybenzoyl glycine)from B.subtilis L9 exhibited a high iron scavenging activity(89.76%).The study was penlights the exploration of probiotic microorganism present in the indigenous fermented food and their capability to biosynthesize siderophore that could be an effective therapeutic aid for maximum absorption of dietary iron and alleviation anemia like micronutrient deficiency diseases as well as to combat hypoxia among the high altitude residents.
文摘This present study identifies endophytic bacteria from Linum usitatissimum with multidimensional plant growth-promoting attributes,positioning them as ecological engineers for sustainable agriculture.Plant growthpromoting bacteria(PGPB)are present in symbiotic associations with plants or rhizosphere.These microbes enhance crop productivity and resilience under different environmental conditions.Endophytes are a type of PGPB that inhabit inside plant tissues and contribute to plant growth by phytohormone production,phosphate solubilisation,zinc solubilisation,siderophore production,ammonia production,nitrogen fixation,stress tolerance,and biocontrol mechanisms.Twelve bacterial strains were isolated from Linum usitatissimum exhibiting plant growth-promoting attributes such as ammonia and indole-3-acetic acid(IAA)production,siderophore synthesis,phosphate solubilisation,and extracellular enzyme synthesis.The isolated endophytes were also assessed for different enzymatic activities such as;cellulase,pectinase,xylanase,amylase,and gelatinase,which contribute to development of a symbiotic relationship and are crucial for the degradation of plant cell wall components The most efficient endophytes identified in the present study were Pseudomonas sp.strain JL-1(ESL1)and Staphylococcus sciuri(ESL2),both of which displayed strong plant growth-promoting potential.ESL1 and ESL2 demonstrated promising plant growth-promoting characteristics and cellulase,pectinase,xylanase,amylase,and gelatinase,activity.ESL2(Staphylococcus sciuri)enhanced nutrient cycling(phosphate solubilisation:196-209μg/ml;siderophores:68-71%)and stress tolerance(IAA:11-12μg/ml),reducing reliance on synthetic inputs.By integrating flax microbiomes into agro-ecosystems,we demonstrate a scalable approach to reconcile crop productivity with soil biodiversity conservation.These results demonstrate the potentiality of these endophytic microbes in sustainable agriculture,environmental management,and microbial biotechnology.Further studies on their metabolic pathways may expand their applications in bioremediation and plant-microbe interactions.
基金This work was supported scientifically by COST Action ESI406“Soil fauna-Key to Soil Organic Matter Dynamics and Modelling(KEYSOM)”.
文摘Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of saline stress in crops.This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria(PGPRs),isolated from the rhizosphere of halophile plants,for the growth,Na^+/K^+balance,ethylene emission,and gene expression of wheat seedlings{Triticum aestivum L.)grown under saline conditions(100 mmol L^-1 NaCl)for 14 d.A total of 118 isolates obtained from saline soils of the deserts of Iran were tested for their capacity as PGPRs.Out of the 118 isolates,17 could solubilize phosphate(Ca3(P〇4)2),5 could produce siderophores,and 16 could synthesize indole-3-acetic acid.Additionally,PGPRs were also evaluated for aminocyclopropane-l-carboxylate deaminase activity.A pot experiment was conducted to evaluate the ability of 28 PGPR isolates to promote growth,regulate Na^+/K^+balance,and decrease ethylene emissions in plants.The most efficient PGPRs were Arthrobacter aurescens.Bacillus atrophaeus,Enterobacter ashuriae,and Pseudomonas fluorescens.Gene expression analysis revealed the up-regulation of H^+-PPase,HKT1,NHX7,CAT,and APX expression in roots of Enterobacter-inocuVdied salt-stressed plants.Salt-tolerant rhizobacteria exhibiting plant growth-promoting traits can facilitate the growth of wheat plants under saline conditions.Our results indicate that the isolation of these bacteria may be useful for formulating new inoculants to improve wheat cropping systems in saline soils.
基金supported by the National Natural Science Foundation of China(Grant No.30328021).
文摘Mutant J61321 with enhanced siderophore production of Alteromonas aurantia AI8 was obtained after a series of chemical-physical mutageneses. It was found that the antibacterial activity against Vibrio anguillarum W-1 and siderophore production of the mutant were higher than those by the original strain A 18 which had been used in mariculture. The results of the specific assay（Csaky and Arnow methods） of siderophore showed that the sidrophore with hydroxamate group was produced by mutant J61321 and the original strain A 18, respectively, while the siderophore with catechol group was yielded by strain W-1 （Aibrio anguillarum）. Meanwhile, the siderophore yield, antibacterial activity and anti-chelator activity of strain J61321 were higher than those of its parent strain A 18.
基金The CAMS Innovation Fund for Medical Sciences(CIFMS 2021-I2M-1-028).
文摘We reported herein the synthesis and antibacterial activity evaluation of two oxazolidinone-deferasirox conjugates with different linkers that were designed based on the“Trojan horse”strategy.The conjugates could combine with Fe^(3+)ions as the deferasirox.However,both conjugates were inactive against tested bacteria,including S.aureus,E.coli,A.baumannii,and P.aeruginosa.The results suggested that the synthesized iron chelator deferasirox was not suitable as a siderophore of the bacteria to transport the antibiotic,or the coupling linker of the synthesized conjugates could not be hydrolyzed to release the oxazolidinone in the cytoplasm.Therefore,the design and synthesis of oxazolidinone-deferasirox conjugates need further exploration.
文摘Klebsiella pneumoniae is an opportunistic pathogen of medical importance and the capsule and mucoid phenotype in this organism are considered as requisite virulence determinants. A total of 62 clinical samples from ATBUTH were collected and screened for K. pneumoniae. The isolates were identified using standard tests for this organism. The string test was used to detect the mucoid (hypermucoviscous) phenotype and the antimicrobial susceptibility test to 10 antibiotics was carried out with the disk diffusion technique after standardizing inoculum. A K. pneumoniae prevalence of 24% (15/62) was obtained of which 47% (7/15) were mucoid (hypermucoviscous) and 53% (8/15) were non-mucoid. Colonial sizes of the two strains do not reveal any significant differences in growth fitness of the strains. On blood agar, the mucoid and non-mucoid strains had a mean colonial size ± standard deviations of 4.41 ± 0.58 mm and 4.27 ± 0.42 mm respectively. The antibiotic susceptibility rate showed that the mucoid strains compared to the non-mucoid were more resistant to nine out of 10 antibiotics. The mucoid strains were outrightly resistant to augmentin, amoxicillin, septrin, sparfloxacin and perfloxacin. The non-mucoid strains showed no complete resistant to any antibiotic tested but had a higher resistant rate to chloramphenicol only. The Multiple Antibiotic Resistance (MAR) index shows the themucoid strains with a high MAR index range of 0.7 - 1.0 with a median MAR index of 0.8, while the non-mucoid strains had a MAR index of 0.2 - 0.8 with a median MAR index of 0.35. The data suggest that the mucoid phenotype could be associated with extrachromsomal element(s) carrying resistance genes to antibiotics and that these extrachromosomal elements may not harbour resistance determinants to chloramphenicol. Furthermore, the extrachromosomal elements bearing the mucoid phenotype and the resistance elements in the mucoid strains do not significantly impact on the fitness of the cognate strain. Whether these phenotype and resistances that had no fitness cost to the bacterium could significantly affect the virulence of the bacteria in vivo remains to be investigated.
