scholarly journals Correlation between Biofilm Formation and the Hypoxic Response in Candida parapsilosis

2009 ◽  
Vol 8 (4) ◽  
pp. 550-559 ◽  
Author(s):  
Tristan Rossignol ◽  
Chen Ding ◽  
Alessandro Guida ◽  
Christophe d'Enfert ◽  
Desmond G. Higgins ◽  
...  
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Candida Parapsilosis ◽  
Transcriptional Profile ◽  
Open Reading Frames ◽  
Hypoxic Response ◽  
Hypoxic Conditions ◽  
Expression Of Genes ◽  
Biofilm Development ◽  
Reading Frames

ABSTRACT The ability of Candida parapsilosis to form biofilms on indwelling medical devices is correlated with virulence. To identify genes that are important for biofilm formation, we used arrays representing approximately 4,000 open reading frames (ORFs) to compare the transcriptional profile of biofilm cells growing in a microfermentor under continuous flow conditions with that of cells in planktonic culture. The expression of genes involved in fatty acid and ergosterol metabolism and in glycolysis, is upregulated in biofilms. The transcriptional profile of C. parapsilosis biofilm cells resembles that of Candida albicans cells grown under hypoxic conditions. We therefore subsequently used whole-genome arrays (representing 5,900 ORFs) to determine the hypoxic response of C. parapsilosis and showed that the levels of expression of genes involved in the ergosterol and glycolytic pathways, together with several cell wall genes, are increased. Our results indicate that there is substantial overlap between the hypoxic responses of C. parapsilosis and C. albicans and that this may be important for biofilm development. Knocking out an ortholog of the cell wall gene RBT1, whose expression is induced both in biofilms and under conditions of hypoxia in C. parapsilosis, reduces biofilm development.

scholarly journals Biochemical and Genetic Analysis of 4-Hydroxypyridine Catabolism in Arthrobacter sp. Strain IN13

2020 ◽  
Vol 8 (6) ◽  
pp. 888
Author(s):  
Justas Vaitekūnas ◽  
Renata Gasparavičiūtė ◽  
Jonita Stankevičiūtė ◽  
Gintaras Urbelis ◽  
Rolandas Meškys
Keyword(s):  
Recombinant Expression ◽  
Expression Profiles ◽  
Peptide Mass Fingerprinting ◽  
Sole Source ◽  
Open Reading Frames ◽  
Expression Of Genes ◽  
Peptide Mass ◽  
Genes Encoding ◽  
Protein Expression Profiles ◽  
Reading Frames

N-Heterocyclic compounds are widely spread in the biosphere, being constituents of alkaloids, cofactors, allelochemicals, and artificial substances. However, the fate of such compounds including a catabolism of hydroxylated pyridines is not yet fully understood. Arthrobacter sp. IN13 is capable of using 4-hydroxypyridine as a sole source of carbon and energy. Three substrate-inducible proteins were detected by comparing protein expression profiles, and peptide mass fingerprinting was performed using MS/MS. After partial sequencing of the genome, we were able to locate genes encoding 4-hydroxypyridine-inducible proteins and identify the kpi gene cluster consisting of 16 open reading frames. The recombinant expression of genes from this locus in Escherichia coli and Rhodococcus erytropolis SQ1 allowed an elucidation of the biochemical functions of the proteins. We report that in Arthrobacter sp. IN13, the initial hydroxylation of 4-hydroxypyridine is catalyzed by a flavin-dependent monooxygenase (KpiA). A product of the monooxygenase reaction is identified as 3,4-dihydroxypyridine, and a subsequent oxidative opening of the ring is performed by a hypothetical amidohydrolase (KpiC). The 3-(N-formyl)-formiminopyruvate formed in this reaction is further converted by KpiB hydrolase to 3-formylpyruvate. Thus, the degradation of 4-hydroxypyridine in Arthrobacter sp. IN13 was analyzed at genetic and biochemical levels, elucidating this catabolic pathway.

scholarly journals Identification and Expression of Genes Involved in Biosynthesis of l-Oleandrose and Its Intermediatel-Olivose in the Oleandomycin ProducerStreptomyces antibioticus

2000 ◽  
Vol 44 (5) ◽  
pp. 1266-1275 ◽  
Author(s):  
Ignacio Aguirrezabalaga ◽  
Carlos Olano ◽  
Nerea Allende ◽  
Leticia Rodriguez ◽  
Alfredo F. Braña ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Gene Cluster ◽  
Enzyme Activities ◽  
Open Reading Frames ◽  
Streptomyces Antibioticus ◽  
Recombinant Strains ◽  
Expression Of Genes ◽  
Streptomyces Albus ◽  
Erythronolide B ◽  
Reading Frames

ABSTRACT A 9.8-kb DNA region from the oleandomycin gene cluster inStreptomyces antibioticus was cloned. Sequence analysis revealed the presence of 8 open reading frames encoding different enzyme activities involved in the biosynthesis of one of the two 2,6-deoxysugars attached to the oleandomycin aglycone:l-oleandrose (the oleW, oleV,oleL, and oleU genes) andd-desosamine (the oleNI and oleTgenes), or of both (the oleS and oleE genes). AStreptomyces albus strain harboring the oleG2glycosyltransferase gene integrated into the chromosome was constructed. This strain was transformed with two different plasmid constructs (pOLV and pOLE) containing a set of genes proposed to be required for the biosynthesis of dTDP-l-olivose and dTDP-l-oleandrose, respectively. Incubation of these recombinant strains with the erythromycin aglycon (erythronolide B) gave rise to two new glycosylated compounds, identified asl-3-O-olivosyl- andl-3-O-oleandrosyl-erythronolide B, indicating that pOLV and pOLE encode all enzyme activities required for the biosynthesis of these two 2,6-dideoxysugars. A pathway is proposed for the biosynthesis of these two deoxysugars in S. antibioticus.

scholarly journals Pseudomonas aeruginosa secreted factors impair biofilm development in Candida albicans

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1476-1486 ◽  
Author(s):  
Lucy J. Holcombe ◽  
Gordon McAlester ◽  
Carol A. Munro ◽  
Brice Enjalbert ◽  
Alistair J. P. Brown ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Homoserine Lactone ◽  
Strong Increase ◽  
Opportunistic Pathogens ◽  
Secreted Factors ◽  
Expression Of Genes ◽  
Biofilm Development

Signal-mediated interactions between the human opportunistic pathogens Pseudomonas aeruginosa and Candida albicans affect virulence traits in both organisms. Phenotypic studies revealed that bacterial supernatant from four P. aeruginosa strains strongly reduced the ability of C. albicans to form biofilms on silicone. This was largely a consequence of inhibition of biofilm maturation, a phenomenon also observed with supernatant prepared from non-clinical bacterial species. The effects of supernatant on biofilm formation were not mediated via interference with the yeast–hyphal morphological switch and occurred regardless of the level of homoserine lactone (HSL) produced, indicating that the effect is HSL-independent. A transcriptome analysis to dissect the effects of the P. aeruginosa supernatants on gene expression in the early stages of C. albicans biofilm formation identified 238 genes that exhibited reproducible changes in expression in response to all four supernatants. In particular, there was a strong increase in the expression of genes related to drug or toxin efflux and a decrease in expression of genes associated with adhesion and biofilm formation. Furthermore, expression of YWP1, which encodes a protein known to inhibit biofilm formation, was significantly increased. Biofilm formation is a key aspect of C. albicans infections, therefore the capacity of P. aeruginosa to antagonize this has clear biomedical implications.

scholarly journals Five Additional Genes Are Involved in Clavulanic Acid Biosynthesis in Streptomyces clavuligerus

2004 ◽  
Vol 48 (1) ◽  
pp. 192-202 ◽  
Author(s):  
S. E. Jensen ◽  
A. S. Paradkar ◽  
R. H. Mosher ◽  
C. Anders ◽  
P. H. Beatty ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clavulanic Acid ◽  
Gene Cluster ◽  
Acid Production ◽  
Streptomyces Clavuligerus ◽  
Open Reading Frames ◽  
Acid Biosynthesis ◽  
Penicillin Binding Proteins ◽  
Total Absence ◽  
Reading Frames

ABSTRACT An approximately 12.5-kbp region of DNA sequence from beyond the end of the previously described clavulanic acid gene cluster was analyzed and found to encode nine possible open reading frames (ORFs). Involvement of these ORFs in clavulanic acid biosynthesis was assessed by creating mutants with defects in each of the ORFs. orf12 and orf14 had been previously reported to be involved in clavulanic acid biosynthesis. Now five additional ORFs are shown to play a role, since their mutation results in a significant decrease or total absence of clavulanic acid production. Most of these newly described ORFs encode proteins with little similarity to others in the databases, and so their roles in clavulanic acid biosynthesis are unclear. Mutation of two of the ORFs, orf15 and orf16, results in the accumulation of a new metabolite, N-acetylglycylclavaminic acid, in place of clavulanic acid. orf18 and orf19 encode apparent penicillin binding proteins, and while mutations in these genes have minimal effects on clavulanic acid production, their normal roles as cell wall biosynthetic enzymes and as targets for β-lactam antibiotics, together with their clustered location, suggest that they are part of the clavulanic acid gene cluster.

scholarly journals Genetic Analysis of the AdnA Regulon in Pseudomonas fluorescens: Nonessential Role of Flagella in Adhesion to Sand and Biofilm Formation

2003 ◽  
Vol 185 (2) ◽  
pp. 453-460 ◽  
Author(s):  
Eduardo A. Robleto ◽  
Inmaculada López-Hernández ◽  
Mark W. Silby ◽  
Stuart B. Levy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Transcription Factor ◽  
Pseudomonas Fluorescens ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Open Reading Frames ◽  
Cell Processes ◽  
Reading Frames ◽  
Insertion Mutants

ABSTRACT AdnA is a transcription factor in Pseudomonas fluorescens that affects flagellar synthesis, biofilm formation, and sand adhesion. To identify the AdnA regulon, we used a promoterless Tn5-lacZ element to study the phenotypes of insertion mutants in the presence and absence of AdnA. Of 12,000 insertions, we identified seven different putative open reading frames (ORFs) activated by AdnA (named aba for activated by AdnA). aba120 and aba177 showed homology to flgC and flgI, components of the basal body of the flagella in Pseudomonas aeruginosa. Two other insertions, aba18 and aba51, disrupted genes affecting chemotaxis. The mutant loci aba160 (possibly affecting lipopolysaccharide synthesis) and aba175 (unknown function) led to loss of flagella. The mutant bearing aba203 became motile when complemented with adnA, but the mutated gene showed no similarity to known genes. Curiously, aba18, aba51, aba160, and aba203 mutants formed biofilms even in the absence of AdnA, suppressing the phenotype of the adnA deletion mutant. The combined findings suggest that flagella are nonessential for sand attachment or biofilm formation. Sequence and promoter analyses indicate that AdnA affects at least 23 ORFs either directly or by polar effects. These results support the concept that AdnA regulates cell processes other than those directly related to flagellar synthesis and define a broader cadre of genes in P. fluorescens than that described so far for its homolog, FleQ, in P. aeruginosa.

scholarly journals O-Mannosylation in Candida albicans Enables Development of Interkingdom Biofilm Communities

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Lindsay C. Dutton ◽  
Angela H. Nobbs ◽  
Katy Jepson ◽  
Mark A. Jepson ◽  
M. Margaret Vickerman ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Early Stage ◽  
Growth Conditions ◽  
Wild Type ◽  
Content Type ◽  
Subsequent Performance ◽  
Biofilm Development ◽  
Mutant Cells

ABSTRACTCandida albicansis a fungus that colonizes oral cavity surfaces, the gut, and the genital tract.Streptococcus gordoniiis a ubiquitous oral bacterium that has been shown to form biofilm communities withC. albicans. Formation of dual-speciesS. gordonii-C. albicansbiofilm communities involves interaction of theS. gordoniiSspB protein with the Als3 protein on the hyphal filament surface ofC. albicans. Mannoproteins comprise a major component of theC. albicanscell wall, and in this study we sought to determine if mannosylation in cell wall biogenesis ofC. albicanswas necessary for hyphal adhesin functions associated with interkingdom biofilm development. AC. albicans mnt1Δmnt2Δ mutant, with deleted α-1,2-mannosyltransferase genes and thus defective inO-mannosylation, was abrogated in biofilm formation under various growth conditions and produced hyphal filaments that were not recognized byS. gordonii. Cell wall proteomes of hypha-formingmnt1Δmnt2Δ mutant cells showed growth medium-dependent alterations, compared to findings for the wild type, in a range of protein components, including Als1, Als3, Rbt1, Scw1, and Sap9. Hyphal filaments formed bymnt1Δmnt2Δ mutant cells, unlike wild-type hyphae, did not interact withC. albicansAls3 or Hwp1 partner cell wall proteins or withS. gordoniiSspB partner adhesin, suggesting defective functionality of adhesins on themnt1Δmnt2Δ mutant. These observations imply that early stageO-mannosylation is critical for activation of hyphal adhesin functions required for biofilm formation, recognition by bacteria such asS. gordonii, and microbial community development.IMPORTANCEIn the human mouth, microorganisms form communities known as biofilms that adhere to the surfaces present.Candida albicansis a fungus that is often found within these biofilms. We have focused on the mechanisms by whichC. albicansbecomes incorporated into communities containing bacteria, such asStreptococcus. We find that impairment of early stage addition of mannose sugars toC. albicanshyphal filament proteins deleteriously affects their subsequent performance in mediating formation of polymicrobial biofilms. Our analyses provide new understanding of the way that microbial communities develop, and of potential means to controlC. albicansinfections.

scholarly journals Bacteriophage and Phenotypic Variation in Pseudomonas aeruginosa Biofilm Development

2004 ◽  
Vol 186 (23) ◽  
pp. 8066-8073 ◽  
Author(s):  
Jeremy S. Webb ◽  
Mathew Lau ◽  
Staffan Kjelleberg
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenotypic Variation ◽  
Open Reading Frames ◽  
Agar Media ◽  
Small Colony ◽  
Biofilm Development ◽  
And Function ◽  
Postsegregational Killing ◽  
Reading Frames ◽  
A Current

ABSTRACT A current question in biofilm research is whether biofilm-specific genetic processes can lead to differentiation in physiology and function among biofilm cells. In Pseudomonas aeruginosa, phenotypic variants which exhibit a small-colony phenotype on agar media and a markedly accelerated pattern of biofilm development compared to that of the parental strain are often isolated from biofilms. We grew P. aeruginosa biofilms in glass flow cell reactors and observed that the emergence of small-colony variants (SCVs) in the effluent runoff from the biofilms correlated with the emergence of plaque-forming Pf1-like filamentous phage (designated Pf4) from the biofilm. Because several recent studies have shown that bacteriophage genes are among the most highly upregulated groups of genes during biofilm development, we investigated whether Pf4 plays a role in SCV formation during P. aeruginosa biofilm development. We carried out immunoelectron microscopy using anti-Pf4 antibodies and observed that SCV cells, but not parental-type cells, exhibited high densities of Pf4 filaments on the cell surface and that these filaments were often tightly interwoven into complex latticeworks surrounding the cells. Moreover, infection of P. aeruginosa planktonic cultures with Pf4 caused the emergence of SCVs within the culture. These SCVs exhibited enhanced attachment, accelerated biofilm development, and large regions of dead and lysed cells inside microcolonies in a manner identical to that of SCVs obtained from biofilms. We concluded that Pf4 can mediate phenotypic variation in P. aeruginosa biofilms. We also performed partial sequencing and analysis of the Pf4 replicative form and identified a number of open reading frames not previously recognized in the genome of P. aeruginosa, including a putative postsegregational killing operon.

scholarly journals Regulation of the Hypoxic Response in Candida albicans

2010 ◽  
Vol 9 (11) ◽  
pp. 1734-1746 ◽  
Author(s):  
John M. Synnott ◽  
Alessandro Guida ◽  
Siobhan Mulhern-Haughey ◽  
Desmond G. Higgins ◽  
Geraldine Butler
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Regulation Of Gene Expression ◽  
Central Carbon Metabolism ◽  
Adaptation To Hypoxia ◽  
Low Oxygen ◽  
Respiratory Pathway ◽  
Content Type ◽  
Hypoxic Conditions ◽  
Expression Of Genes

ABSTRACT The regulation of the response of Candida albicans to hypoxic (low-oxygen) conditions is poorly understood. We used microarray and other transcriptional analyses to investigate the role of the Upc2 and Bcr1 transcription factors in controlling expression of genes involved in cell wall metabolism, ergosterol synthesis, and glycolysis during adaptation to hypoxia. Hypoxic induction of the ergosterol pathway is mimicked by treatment with sterol-lowering drugs (ketoconazole) and requires UPC2. Expression of three members of the family CFEM (common in several fungal extracellular membranes) of cell wall genes (RBT5, PGA7, and PGA10) is also induced by hypoxia and ketoconazole and requires both UPC2 and BCR1. Expression of glycolytic genes is induced by hypoxia but not by treatment with sterol-lowering drugs, whereas expression of respiratory pathway genes is repressed. However, Upc2 does not play a major role in regulating expression of genes required for central carbon metabolism. Our results indicate that regulation of gene expression in response to hypoxia in C. albicans is complex and is signaled both via lowered sterol levels and other unstudied mechanisms. We also show that induction of filamentation under hypoxic conditions requires the Ras1- and Cdc35-dependent pathway.

scholarly journals Plasmid-Encoded MCP Is Involved in Virulence, Motility, and Biofilm Formation of Cronobacter sakazakii ATCC 29544

2014 ◽  
Vol 83 (1) ◽  
pp. 197-204 ◽  
Author(s):  
Younho Choi ◽  
Seongok Kim ◽  
Hyelyeon Hwang ◽  
Kwang-Pyo Kim ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Protein Gene ◽  
Open Reading Frames ◽  
Insertion Mutant ◽  
Biological Processes ◽  
Cronobacter Sakazakii ◽  
Content Type ◽  
Rat Pups ◽  
Transposon Insertion ◽  
Reading Frames

The aim of this study was to elucidate the function of the plasmid-bornemcp(methyl-accepting chemotaxis protein) gene, which plays pleiotropic roles inCronobacter sakazakiiATCC 29544. By searching for virulence factors using a random transposon insertion mutant library, we identified and sequenced a new plasmid, pCSA2, inC. sakazakiiATCC 29544. Anin silicoanalysis of pCSA2 revealed that it included six putative open reading frames, and one of them wasmcp. Themcpmutant was defective for invasion into and adhesion to epithelial cells, and the virulence of themcpmutant was attenuated in rat pups. In addition, we demonstrated that putative MCP regulates the motility ofC. sakazakii, and the expression of the flagellar genes was enhanced in the absence of a functionalmcpgene. Furthermore, a lack of themcpgene also impaired the ability ofC. sakazakiito form a biofilm. Our results demonstrate a regulatory role for MCP in diverse biological processes, including the virulence ofC. sakazakiiATCC 29544. To the best of our knowledge, this study is the first to elucidate a potential function of a plasmid-encoded MCP homolog in theC. sakazakiisequence type 8 (ST8) lineage.

scholarly journals Cyclic di-GMP Is Integrated Into a Hierarchal Quorum Sensing Network Regulating Antimicrobial Production and Biofilm Formation in Roseobacter Clade Member Rhodobacterales Strain Y4I

2021 ◽  
Vol 8 ◽  
Author(s):  
April C. Armes ◽  
Alison Buchan
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Roseobacter Clade ◽  
Partial Restoration ◽  
Microbial Biofilms ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Biofilm Development ◽  
And Function

Microbial biofilms associated with marine particulate organic matter carry out transformations that influence local and regional biogeochemical cycles. Early microbial colonizers are often hypothesized to “set the stage” for biofilm structure, dynamics, and function via N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS). Production of AHLs, as well as antimicrobials, contributes to the colonization success of members of the Roseobacter clade. One member of this group of abundant marine bacteria, Rhodobacterales sp. Y4I, possesses two QS systems, phaRI (QS1) and pgaRI (QS2). Here, we characterize mutants in both QS systems to provide genetic evidence that the two systems work in hierarchical fashion to coordinate production of the antimicrobial indigoidine as well as biofilm formation. A mutation in pgaR (QS2) results in decreased expression of genes encoding both QS systems as well as those governing the biosynthesis of indigoidine. In contrast, mutations in QS1 did not significantly influence gene expression of QS2. Addition of exogenous AHLs to QS1 and QS2 mutants led to partial restoration of indigoidine production (45–60% of WT) for QS1 but not QS2. Mutational disruptions of QS1 had a more pronounced effect on biofilm development than those in QS2. Finally, we demonstrate that c-di-GMP levels are altered in QS and indigoidine biosynthesis Y4I mutants. Together, these results indicate that pgaRI (QS2) is at the top of a regulatory hierarchy governing indigoidine biosynthesis and that the global regulatory metabolite, c-di-GMP, is likely integrated into the QS circuitry of this strain. These findings provide mechanistic understanding of physiological processes that are important in elucidating factors driving competitiveness of Roseobacters in nature.

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