scholarly journals Genome-Based Cluster Deletion Reveals an Endocrocin Biosynthetic Pathway in Aspergillus fumigatus

2012 ◽  
Vol 78 (12) ◽  
pp. 4117-4125 ◽  
Author(s):  
Fang Yun Lim ◽  
Yanpeng Hou ◽  
Yiming Chen ◽  
Jee-Hwan Oh ◽  
Inhyung Lee ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Gene Cluster ◽  
Biosynthetic Pathway ◽  
Polyketide Synthase ◽  
Wild Type Strain ◽  
Global Regulator ◽  
Content Type ◽  
In The Wild ◽  
Secondary Metabolite Gene Cluster

ABSTRACTEndocrocin is a simple anthraquinone frequently identified in extracts of numerous fungi. Several biosynthetic schemes for endocrocin synthesis have been hypothesized, but to date, no dedicated secondary metabolite gene cluster that produces this polyketide as its major metabolite has been identified. Here we describe our biosynthetic and regulatory characterization of the endocrocin gene cluster inAspergillus fumigatus. This is the first report of this anthraquinone in this species. The biosynthetic genes required for endocrocin production are regulated by the global regulator of secondary metabolism, LaeA, and encode an iterative nonreducing polyketide synthase (encA), a physically discrete metallo-β-lactamase type thioesterase (encB), and a monooxygenase (encC). Interestingly, the deletion of a gene immediately adjacent toencC, termedencDand encoding a putative 2-oxoglutarate-Fe(II) type oxidoreductase, resulted in higher levels of endocrocin production than in the wild-type strain, whereas overexpression ofencDeliminated endocrocin accumulation. We found that overexpression of theencAtranscript resulted in higher transcript levels ofencA-Dand higher production of endocrocin. We discuss a model of theenccluster as one evolutionary origin of fungal anthraquinones derived from a nonreducing polyketide synthase and a discrete metallo-β-lactamase-type thioesterase.

scholarly journals Biosynthesis of Fusarubins Accounts for Pigmentation of Fusarium fujikuroi Perithecia

2012 ◽  
Vol 78 (12) ◽  
pp. 4468-4480 ◽  
Author(s):  
Lena Studt ◽  
Philipp Wiemann ◽  
Karin Kleigrewe ◽  
Hans-Ulrich Humpf ◽  
Bettina Tudzynski
Keyword(s):  
Secondary Metabolites ◽  
Gene Cluster ◽  
Biosynthetic Pathway ◽  
Polyketide Synthase ◽  
Biological Function ◽  
Fusarium Fujikuroi ◽  
Diverse Group ◽  
Fruiting Bodies ◽  
Content Type ◽  
Encoding Gene

ABSTRACTFusarium fujikuroiproduces a variety of secondary metabolites, of which polyketides form the most diverse group. Among these are the highly pigmented naphthoquinones, which have been shown to possess different functional properties for the fungus. A group of naphthoquinones, polyketides related to fusarubin, were identified inFusariumspp. more than 60 years ago, but neither the genes responsible for their formation nor their biological function has been discovered to date. In addition, although it is known that the sexual fruiting bodies in which the progeny of the fungus develops are darkly colored by a polyketide synthase (PKS)-derived pigment, the structure of this pigment has never been elucidated. Here we present data that link the fusarubin-type polyketides to a defined gene cluster, which we designatefsr, and demonstrate that the fusarubins are the pigments responsible for the coloration of the perithecia. We studied their regulation and the function of the single genes within the cluster by a combination of gene replacements and overexpression of the PKS-encoding gene, and we present a model for the biosynthetic pathway of the fusarubins based on these data.

scholarly journals A Novel CO-Responsive Transcriptional Regulator and Enhanced H2Production by an Engineered Thermococcus onnurineus NA1 Strain

2014 ◽  
Vol 81 (5) ◽  
pp. 1708-1714 ◽  
Author(s):  
Min-Sik Kim ◽  
Ae Ran Choi ◽  
Seong Hyuk Lee ◽  
Hae-Chang Jung ◽  
Seung Seob Bae ◽  
...  
Keyword(s):  
Production Rate ◽  
Gene Cluster ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory System ◽  
Transcriptional Regulator ◽  
Bioreactor Culture ◽  
Wild Type ◽  
Content Type ◽  
Transcriptional Regulatory

ABSTRACTGenome analysis revealed the existence of a putative transcriptional regulatory system governing CO metabolism inThermococcus onnurineusNA1, a carboxydotrophic hydrogenogenic archaeon. The regulatory system is composed of CorQ with a 4-vinyl reductase domain and CorR with a DNA-binding domain of the LysR-type transcriptional regulator family in close proximity to the CO dehydrogenase (CODH) gene cluster. Homologous genes of the CorQR pair were also found in the genomes ofThermococcusspecies and “CandidatusKorarchaeum cryptofilum” OPF8. In-frame deletion of eithercorQorcorRcaused a severe impairment in CO-dependent growth and H2production. WhencorQandcorRdeletion mutants were complemented by introducing thecorQRgenes under the control of a strong promoter, the mRNA and protein levels of the CODH gene were significantly increased in a ΔCorR strain complemented with integratedcorQR(ΔCorR/corQR↑) compared with those in the wild-type strain. In addition, the ΔCorR/corQR↑strain exhibited a much higher H2production rate (5.8-fold) than the wild-type strain in a bioreactor culture. The H2production rate (191.9 mmol liter−1h−1) and the specific H2production rate (249.6 mmol g−1h−1) of this strain were extremely high compared with those of CO-dependent H2-producing prokaryotes reported so far. These results suggest that thecorQRgenes encode a positive regulatory protein pair for the expression of a CODH gene cluster. The study also illustrates that manipulation of the transcriptional regulatory system can improve biological H2production.

Characterization of Enterococcus faecium mutants resistant to mundticin KS, a class IIa bacteriocin

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2901-2908 ◽  
Author(s):  
Youko Sakayori ◽  
Mizuho Muramatsu ◽  
Satoshi Hanada ◽  
Yoichi Kamagata ◽  
Shinichi Kawamoto ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Antimicrobial Agents ◽  
Wild Type Strain ◽  
Unsaturated Fatty Acids ◽  
Class I ◽  
Wild Type ◽  
Food Preservatives ◽  
In The Wild ◽  
Resistant Mutants

The emergence and spread of mutants resistant to bacteriocins would threaten the safety of using bacteriocins as food preservatives. To determine the physiological characteristics of resistant mutants, mutants of Enterococcus faecium resistant to mundticin KS, a class IIa bacteriocin, were isolated. Two types of mutant were found that had different sensitivities to other antimicrobial agents such as nisin (class I) and kanamycin. Both mutants were resistant to mundticin KS even in the absence of Mg2+ ions. The composition of unsaturated fatty acids in the resistant mutants was significantly increased in the presence of mundticin KS. The composition of the phospholipids in the two resistant mutants also differed from those in the wild-type strain. The putative zwitterionic amino-containing phospholipid in both mutants significantly increased, whereas amounts of phosphatidylglycerol and cardiolipin decreased. These changes in membrane structure may influence resistance of enterococci to class IIa and class I bacteriocins.

scholarly journals Activation of 2,4-Diaminoquinazoline in Mycobacterium tuberculosis by Rv3161c, a Putative Dioxygenase

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Eduard Melief ◽  
Shilah A. Bonnett ◽  
Edison S. Zuniga ◽  
Tanya Parish
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Type A ◽  
Wild Type ◽  
Metabolite Analysis ◽  
Content Type ◽  
Data Support ◽  
In The Wild

ABSTRACT The diaminoquinazoline series has good potency against Mycobacterium tuberculosis. Resistant isolates have mutations in Rv3161c, a putative dioxygenase. We carried out metabolite analysis on a wild-type strain and an Rv3161c mutant strain after exposure to a diaminoquinazoline. The parental compound was found in intracellular extracts from the mutant but not the wild type. A metabolite consistent with a monohydroxylated form was identified in the wild type. These data support the hypothesis that Rv3161c metabolizes diaminoquinazolines in M. tuberculosis.

Biosynthesis of the uridine-derived nucleoside antibiotic A-94964: identification and characterization of the biosynthetic gene cluster provide insight into the biosynthetic pathway

2019 ◽  
Vol 17 (3) ◽  
pp. 461-466 ◽  
Author(s):  
Taro Shiraishi ◽  
Makoto Nishiyama ◽  
Tomohisa Kuzuyama
Keyword(s):  
Gene Cluster ◽  
In Silico ◽  
Biosynthetic Pathway ◽  
Gene Deletion ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Identification And Characterization ◽  
Insight Into

The biosynthetic pathway of the uridine-derived nucleoside antibiotic A-94964 was proposed via in silico analysis coupled with gene deletion experiments.

scholarly journals Ubiquinone Biosynthesis over the Entire O2Range: Characterization of a Conserved O2-Independent Pathway

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Ludovic Pelosi ◽  
Chau-Duy-Tam Vo ◽  
Sophie Saphia Abby ◽  
Laurent Loiseau ◽  
Bérengère Rascalou ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Lipid Binding ◽  
The Novel ◽  
Human Pathogens ◽  
Terminal Electron Acceptor ◽  
Content Type ◽  
Metabolic Plasticity ◽  
Accessory Factor ◽  
Cellular Bioenergetics

ABSTRACTMost bacteria can generate ATP by respiratory metabolism, in which electrons are shuttled from reduced substrates to terminal electron acceptors, via quinone molecules like ubiquinone. Dioxygen (O2) is the terminal electron acceptor of aerobic respiration and serves as a co-substrate in the biosynthesis of ubiquinone. Here, we characterize a novel, O2-independent pathway for the biosynthesis of ubiquinone. This pathway relies on three proteins, UbiT (YhbT), UbiU (YhbU), and UbiV (YhbV). UbiT contains an SCP2 lipid-binding domain and is likely an accessory factor of the biosynthetic pathway, while UbiU and UbiV (UbiU-UbiV) are involved in hydroxylation reactions and represent a novel class of O2-independent hydroxylases. We demonstrate that UbiU-UbiV form a heterodimer, wherein each protein binds a 4Fe-4S cluster via conserved cysteines that are essential for activity. The UbiT, -U, and -V proteins are found in alpha-, beta-, and gammaproteobacterial clades, including several human pathogens, supporting the widespread distribution of a previously unrecognized capacity to synthesize ubiquinone in the absence of O2. Together, the O2-dependent and O2-independent ubiquinone biosynthesis pathways contribute to optimizing bacterial metabolism over the entire O2range.IMPORTANCEIn order to colonize environments with large O2gradients or fluctuating O2levels, bacteria have developed metabolic responses that remain incompletely understood. Such adaptations have been recently linked to antibiotic resistance, virulence, and the capacity to develop in complex ecosystems like the microbiota. Here, we identify a novel pathway for the biosynthesis of ubiquinone, a molecule with a key role in cellular bioenergetics. We link three uncharacterized genes ofEscherichia colito this pathway and show that the pathway functions independently from O2. In contrast, the long-described pathway for ubiquinone biosynthesis requires O2as a substrate. In fact, we find that many proteobacteria are equipped with the O2-dependent and O2-independent pathways, supporting that they are able to synthesize ubiquinone over the entire O2range. Overall, we propose that the novel O2-independent pathway is part of the metabolic plasticity developed by proteobacteria to face various environmental O2levels.

scholarly journals Glycerol Utilization Gene Cluster in Streptomyces clavuligerus

2009 ◽  
Vol 75 (9) ◽  
pp. 2991-2995 ◽  
Author(s):  
Sonia Baños ◽  
Rosario Pérez-Redondo ◽  
Bert Koekman ◽  
Paloma Liras
Keyword(s):  
Clavulanic Acid ◽  
Gene Cluster ◽  
Acid Production ◽  
Type Strain ◽  
Wild Type Strain ◽  
Streptomyces Clavuligerus ◽  
Wild Type ◽  
Glycerol Utilization ◽  
In The Wild

ABSTRACT The Streptomyces clavuligerus ATCC 27064 glycerol cluster gylR-glpF1K1D1 is induced by glycerol but is not affected by glucose. S. clavuligerus growth and clavulanic acid production are stimulated by glycerol, but this does not occur in a glpK1-deleted mutant. Amplification of glpK1D1 results in transformants yielding larger amounts of clavulanic acid in the wild-type strain and in overproducer S. clavuligerus Gap15-7-30 or S. clavuligerus ΔrelA strains.

scholarly journals Production of the Antimicrobial Secondary Metabolite Indigoidine Contributes to Competitive Surface Colonization by the Marine Roseobacter Phaeobacter sp. Strain Y4I

2012 ◽  
Vol 78 (14) ◽  
pp. 4771-4780 ◽  
Author(s):  
W. Nathan Cude ◽  
Jason Mooney ◽  
Arash A. Tavanaei ◽  
Mary K. Hadden ◽  
Ashley M. Frank ◽  
...  
Keyword(s):  
Gene Expression ◽  
Secondary Metabolite ◽  
Biosynthetic Pathway ◽  
Wild Type Strain ◽  
Vibrio Fischeri ◽  
Random Mutagenesis ◽  
Blue Pigment ◽  
Wild Type ◽  
Content Type ◽  
Artificial Surface

ABSTRACTMembers of theRoseobacterlineage of marine bacteria are prolific surface colonizers in marine coastal environments, and antimicrobial secondary metabolite production has been hypothesized to provide a competitive advantage to colonizing roseobacters. Here, we report that the roseobacterPhaeobactersp. strain Y4I produces the blue pigment indigoidine via a nonribosomal peptide synthase (NRPS)-based biosynthetic pathway encoded by a novel series of genetically linked genes:igiBCDFE. A Tn5-based random mutagenesis library of Y4I showed a perfect correlation between indigoidine production by thePhaeobacterstrain and inhibition ofVibrio fischerion agar plates, revealing a previously unrecognized bioactivity of this molecule. In addition, igiD null mutants (igiD encoding the indigoidine NRPS) were more resistant to hydrogen peroxide, less motile, and faster to colonize an artificial surface than the wild-type strain. Collectively, these data provide evidence for pleiotropic effects of indigoidine production in this strain. Gene expression assays support phenotypic observations and demonstrate thatigiDgene expression is upregulated during growth on surfaces. Furthermore, competitive cocultures ofV. fischeriand Y4I show that the production of indigoidine by Y4I significantly inhibits colonization ofV. fischerion surfaces. This study is the first to characterize a secondary metabolite produced by an NRPS in roseobacters.

scholarly journals Laccases Involved in 1,8-Dihydroxynaphthalene Melanin Biosynthesis in Aspergillus fumigatus Are Regulated by Developmental Factors and Copper Homeostasis

2013 ◽  
Vol 12 (12) ◽  
pp. 1641-1652 ◽  
Author(s):  
Srijana Upadhyay ◽  
Guadalupe Torres ◽  
Xiaorong Lin
Keyword(s):  
Immune Responses ◽  
Aspergillus Fumigatus ◽  
Gene Cluster ◽  
Gene Expression Pattern ◽  
Copper Homeostasis ◽  
Copper Level ◽  
Fungal Virulence ◽  
Copper Transporter ◽  
Melanin Biosynthesis ◽  
Content Type

ABSTRACTAspergillus fumigatusproduces heavily melanized infectious conidia. The conidial melanin is associated with fungal virulence and resistance to various environmental stresses. This 1,8-dihydroxynaphthalene (DHN) melanin is synthesized by enzymes encoded in a gene cluster inA. fumigatus, including two laccases, Abr1 and Abr2. Although this gene cluster is not conserved in all aspergilli, laccases are critical for melanization in all species examined. Here we show that the expression ofA. fumigatuslaccases Abr1/2 is upregulated upon hyphal competency and drastically increased during conidiation. The Abr1 protein is localized at the surface of stalks and conidiophores, but not in young hyphae, consistent with the gene expression pattern and its predicted role. The induction of Abr1/2 upon hyphal competency is controlled by BrlA, the master regulator of conidiophore development, and is responsive to the copper level in the medium. We identified a developmentally regulated putative copper transporter, CtpA, and found that CtpA is critical for conidial melanization under copper-limiting conditions. Accordingly, disruption of CtpA enhanced the induction ofabr1andabr2, a response similar to that induced by copper starvation. Furthermore, nonpigmentedctpAΔ conidia elicited much stronger immune responses from the infected invertebrate hostGalleria mellonellathan the pigmentedctpAΔ or wild-type conidia. Such enhancement in elicitingGalleriaimmune responses was independent of thectpAΔ conidial viability, as previously observed for the DHN melanin mutants. Taken together, our findings indicate that both copper homeostasis and developmental regulators control melanin biosynthesis, which affects conidial surface properties that shape the interaction between this pathogen and its host.

scholarly journals Molecular Characterization of a Voriconazole-Resistant, Posaconazole-Susceptible Aspergillus fumigatus Isolate in a Lung Transplant Recipient in the United States

2015 ◽  
Vol 60 (2) ◽  
pp. 1129-1133 ◽  
Author(s):  
Jose A. Vazquez ◽  
Elias K. Manavathu
Keyword(s):  
United States ◽  
Aspergillus Fumigatus ◽  
Molecular Characterization ◽  
Lung Transplant ◽  
Transplant Patient ◽  
The United States ◽  
Azole Resistance ◽  
Content Type ◽  
High Level

ABSTRACTMolecular characterization ofcyp51Afrom the azole-resistantAspergillus fumigatusisolate 50593 from a lung transplant patient showed Y121F/T289A changes coupled with a 46-bp tandem repeat (TR46) on the promoter, whereascyp51Afrom the pretherapy isolate,A. fumigatus47381, showed no changes. This is the first reported case ofA. fumigatusazole resistance due to Y121F/T289A/TR46 in the United States, suggesting that multiple mutational alterations ofcyp51Aresulting in high-level azole resistance could occur during prolonged antifungal therapy.

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