Abstract:
:Transcriptomic, metabolomic, physiological, and computational modeling approaches were integrated to gain insight into the mechanisms of antibiotic tolerance in an in vitro biofilm system. Pseudomonas aeruginosa biofilms were grown in drip flow reactors on a medium composed to mimic the exudate from a chronic wound. After 4 days, the biofilm was 114 μm thick with 9.45 log10 CFU cm-2 These biofilms exhibited tolerance, relative to exponential-phase planktonic cells, to subsequent treatment with ciprofloxacin. The specific growth rate of the biofilm was estimated via elemental balances to be approximately 0.37 h-1 and with a reaction-diffusion model to be 0.32 h-1, or one-third of the maximum specific growth rate for planktonic cells. Global analysis of gene expression indicated lower transcription of ribosomal genes and genes for other anabolic functions in biofilms than in exponential-phase planktonic cells and revealed the induction of multiple stress responses in biofilm cells, including those associated with growth arrest, zinc limitation, hypoxia, and acyl-homoserine lactone quorum sensing. Metabolic pathways for phenazine biosynthesis and denitrification were transcriptionally activated in biofilms. A customized reaction-diffusion model predicted that steep oxygen concentration gradients will form when these biofilms are thicker than about 40 μm. Mutant strains that were deficient in Psl polysaccharide synthesis, the stringent response, the stationary-phase response, and the membrane stress response exhibited increased ciprofloxacin susceptibility when cultured in biofilms. These results support a sequence of phenomena leading to biofilm antibiotic tolerance, involving oxygen limitation, electron acceptor starvation and growth arrest, induction of associated stress responses, and differentiation into protected cell states.IMPORTANCE Bacteria in biofilms are protected from killing by antibiotics, and this reduced susceptibility contributes to the persistence of infections such as those in the cystic fibrosis lung and chronic wounds. A generalized conceptual model of biofilm antimicrobial tolerance with the following mechanistic steps is proposed: (i) establishment of concentration gradients in metabolic substrates and products; (ii) active biological responses to these changes in the local chemical microenvironment; (iii) entry of biofilm cells into a spectrum of states involving alternative metabolisms, stress responses, slow growth, cessation of growth, or dormancy (all prior to antibiotic treatment); (iv) adaptive responses to antibiotic exposure; and (v) reduced susceptibility of microbial cells to antimicrobial challenges in some of the physiological states accessed through these changes.
journal_name
J Bacterioljournal_title
Journal of bacteriologyauthors
Stewart PS,White B,Boegli L,Hamerly T,Williamson KS,Franklin MJ,Bothner B,James GA,Fisher S,Vital-Lopez FG,Wallqvist Adoi
10.1128/JB.00307-19subject
Has Abstractpub_date
2019-10-21 00:00:00issue
22eissn
0021-9193issn
1098-5530pii
JB.00307-19journal_volume
201pub_type
杂志文章abstract::In response to iron limitation, the siderophore enterobactin is synthesized and secreted by Escherichia coli. Its biosynthesis is performed by a series of enzymes encoded by the Ent gene cluster. Among the genes of this cluster, ybdB has not been implicated in enterobactin production to date. We demonstrate here an in...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00755-07
更新日期:2007-10-01 00:00:00
abstract::The importance of the physiological state of a culture of Saccharomyces cerevisiae for tolerance to sudden osmotic dehydration was studied, and it was investigated whether specific osmotolerance factors were demonstrable. The microcalorimeter was used to monitor growth, and different physiological states of the cultur...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.170.10.4562-4568.1988
更新日期:1988-10-01 00:00:00
abstract::Hyaluronate stimulated the formation of exolipase by Serratia marcescens. This ability was abolished when all carboxyl groups of hyaluronate were methyl esterified. Additional studies suggested that the biological inactivity of esterified hyaluronate should be ascribed to the reduced conformational order of the molecu...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.139.3.1065-1067.1979
更新日期:1979-09-01 00:00:00
abstract::Leucine and isoleucine-valine loci have been mapped in Rhizobium japonicum. Transformation analysis suggests a common pathway for isoleucine-valine biosynthesis. Three-point reciprocal crosses indicated that all the leucine loci are not genetically linked. ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.126.2.997-998.1976
更新日期:1976-05-01 00:00:00
abstract::Agrobacterium tumefaciens A281 induces large, rapidly appearing tumors on a variety of plants and has a wider host range than other strains of A. tumefaciens. By using Tn3HoHo1 transposon mutagenesis and complementation analysis, a 2.5-kilobase DNA fragment which is responsible for the supervirulence phenotype was ide...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.169.10.4417-4425.1987
更新日期:1987-10-01 00:00:00
abstract::The glycosyltransferase (GT) module of class A penicillin-binding proteins (PBPs) and monofunctional GTs (MGTs) belong to the GT51 family in the sequence-based classification of GTs. They both possess five conserved motifs and use lipid II precursor (undecaprenyl-pyrophosphate-N-acetylglucosaminyl-N-acetylmuramoyl- pe...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.188.7.2528-2532.2006
更新日期:2006-04-01 00:00:00
abstract::The mecA-27r gene, which encodes PBP2a-27r, was modified by site-specific mutagenesis, resulting in replacement of the N-terminal membrane anchor with a short chelating peptide (CP-PBP2a-27r). CP-PBP2a-27r retained the same binding affinity for beta-lactam antibiotics as the wild-type enzyme. Approximately 95% pure CP...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.176.5.1539-1541.1994
更新日期:1994-03-01 00:00:00
abstract::The RecA proteins of the unusually strong protease-constitutive mutants recA1202 and recA1211 can use RNA in addition to single-stranded DNA (ssDNA) as a cofactor in the cleavage of the LexA repressor in vitro. In the presence of rRNA or tRNA, the effectiveness of these proteins decreased in the order RecA1202 greater...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.170.10.4823-4827.1988
更新日期:1988-10-01 00:00:00
abstract::Extraction with pentane virtually abolished reduced nicotinamide adenine dinucleotide oxidase activity in small particles from Azotobacter vinelandii, but activity was largely restored by added ubiquinone. ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.98.1.311-313.1969
更新日期:1969-04-01 00:00:00
abstract::5-methylcytosine in chromosomal DNA represents a potential source of frequent spontaneous mutation for hyperthermophiles. To determine the relevance of this threat for the archaeon Sulfolobus acidocaldarius, the mode of GGCC methylation by its restriction-modification system, SuaI, was investigated. Distinct isoschizo...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.185.15.4657-4661.2003
更新日期:2003-08-01 00:00:00
abstract::Pseudomonas putida DOT-T1 was isolated after enrichment on minimal medium with 1% (vol/vol) toluene as the sole C source. The strain was able to grow in the presence of 90% (vol/vol) toluene and was tolerant to organic solvents whose log P(ow) (octanol/water partition coefficient) was higher than 2.3. Solvent toleranc...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.177.14.3911-3916.1995
更新日期:1995-07-01 00:00:00
abstract::Candida albicans produces large amounts of the acyclic pentitol D-arabitol in culture and in infected animals and humans, and most strains also grow on minimal D-arabitol medium. An earlier study showed that the major metabolic precursor of D-arabitol in C. albicans was D-ribulose-5-PO4 from the pentose pathway, that ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.177.11.2971-2976.1995
更新日期:1995-06-01 00:00:00
abstract::5-Azacytidine was found to be bactericidal to Escherichia coli carrying plasmids specifying EcoRII restriction-modification systems, but not to the same strains lacking these plasmids. Of other base analogs tested, only 5(beta-D-ribofuranosyl)isocytidine had similar, although weaker, effects. Plasmids that had lost th...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.151.1.262-268.1982
更新日期:1982-07-01 00:00:00
abstract::The major sheath protein-encoding gene (mspA) of the oral spirochete Treponema maltophilum ATCC 51939(T) was cloned by screening a genomic library with an anti-outer membrane fraction antibody. The mspA gene encodes a precursor protein of 575 amino acids with a predicted molecular mass of 62.3 kDa, including a signal ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.181.3.1025-1029.1999
更新日期:1999-02-01 00:00:00
abstract::Austrian, Robert (The University of Pennsylvania School of Medicine, Philadelphia), and Patricia Collins. Importance of carbon dioxide in the isolation of pneumococci. J. Bacteriol. 92:1281-1284. 1966.-Of the strains of pneumococci isolated from man, 8% manifest a requirement for CO(2) if detectable growth is to occur...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.92.5.1281-1284.1966
更新日期:1966-11-01 00:00:00
abstract::Fukuyama T. T. (University of Pennsylvania, Philadelphia) and D. J. O'Kane. Galactose metabolism. I. Pathway of carbon in fermentation by Streptococcus faecalis. J. Bacteriol. 84:793-796. 1962.-The pathway by which galactose-1-C(14) is fermented in Streptococcus faecalis was investigated using dried-cell preparations....
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.84.4.793-796.1962
更新日期:1962-10-01 00:00:00
abstract::In Escherichia coli K-12, the rcsA and rcsB gene products are positive regulators in expression of the slime polysaccharide colanic acid. We have previously demonstrated the presence of rcsA sequences in E. coli K1 and K5, strains with group II capsular K antigens, and shown that introduction of multicopy rcsA into th...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.175.20.6725-6730.1993
更新日期:1993-10-01 00:00:00
abstract::Using a quantitative assay for measuring chemotaxis, we tested a variety of sugars and sugar derivatives for their ability to attract Escherichia coli bacteria. The most effective attractants, i.e., those that have thresholds near 10(-5) M or below, are N-acetyl-d-glucosamine, 6-deoxy-d-glucose, d-fructose, d-fucose, ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.115.3.824-847.1973
更新日期:1973-09-01 00:00:00
abstract::Hydrolytic deamination of cytosine to uracil in DNA is increased in organisms adapted to high temperatures. Hitherto, the uracil base excision repair (BER) pathway has only been described in two archaeons, the crenarchaeon Pyrobaculum aerophilum and the euryarchaeon Archaeoglobus fulgidus, which are hyperthermophiles ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00233-11
更新日期:2011-09-01 00:00:00
abstract::LcrV, an essential piece of the Yop virulon, is encoded by the large lcrGVsycDyopBD operon. In spite of repeated efforts, the role of LcrV in the Yop virulon remains elusive. In an attempt to clarify this, we engineered a complete deletion of lcrV in the pYV plasmid of Yersinia enterocolitica E40 and characterized the...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.180.5.1207-1214.1998
更新日期:1998-03-01 00:00:00
abstract::Membrane vesicles containing internal alcohol dehydrogenase and nicotinamide adenine dinucleotide (NAD) were prepared from Escherichia coli ML308-225. Upon the addition of ethanol, these vesicles respired and transported several amino acids. Transport rates driven by internally generated reduced NAD (NADH) were about ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.120.2.861-865.1974
更新日期:1974-11-01 00:00:00
abstract::Cells of Saccharomyces cerevisiae permeabilized by treatment with ether take up and incorporate exogenous deoxynucleoside triphosphate into deoxyribonucleic acid (DNA). With rho(+) strains, more than 95% of the product was mitochondrial DNA (mtDNA). This report characterizes ether-permeabilized yeast cells and describ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.140.2.333-341.1979
更新日期:1979-11-01 00:00:00
abstract::The host range of an octopine Ti plasmid is limited to Rhizobiaceae. This has been extended also to Escherichia coli in the form of a stable cointegrate with the wide-host-range plasmid R772. Its structure was studied by constructing a physical map of R772 and of the R772::pTiB6 cointegrate. An insertion sequence pres...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.154.2.693-701.1983
更新日期:1983-05-01 00:00:00
abstract::In Escherichia coli, the SecB/SecA branch of the Sec pathway and the twin-arginine translocation (Tat) pathway represent two alternative possibilities for posttranslational translocation of proteins across the cytoplasmic membrane. Maintenance of pathway specificity was analyzed using a model precursor consisting of t...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.185.9.2811-2819.2003
更新日期:2003-05-01 00:00:00
abstract::Previous determination of the nucleotide sequence of the iol region of the Bacillus subtilis genome allowed us to predict the structure of the iol operon for myo-inositol catabolism, consisting of 10 iol genes (iolA to iouJ); iolG corresponds to idh, encoding myo-inositol 2-dehydrogenase (Idh). Primer extension analys...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.179.14.4591-4598.1997
更新日期:1997-07-01 00:00:00
abstract::In Streptococcus mutans, enzyme II(scr) and sucrose-6-phosphate hydrolase are two important enzymes in the transport and metabolism of dietary sucrose. The scr regulon of S. mutans is composed of three genes, scrA and scrB, which code for enzyme II(scr) and sucrose-6-phosphate hydrolase, respectively, and scrR, which ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.185.19.5791-5799.2003
更新日期:2003-10-01 00:00:00
abstract::Horizontal acquisition of novel chromosomal genes is considered to be a key process in the evolution of bacterial pathogens. However, the identification of gene presence or absence could be hindered by the inconsistencies in bacterial genome annotations. Here, we performed a cross-annotation of omnipresent core and mo...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00545-16
更新日期:2016-11-04 00:00:00
abstract::Aspergillus fumigatus secretes a number of glycosidases into the culture medium when the cells are grown in a mineral salts medium containing guar flour (a galactomannan) as the carbon source. At least some of these glycosidases have been reported to be glycoproteins having N-linked oligosaccharides. In this study, we...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.160.1.67-75.1984
更新日期:1984-10-01 00:00:00
abstract::The effects of surfaces on the physiology of bacteria adhering to surfaces or immobilized within biofilms are receiving more interest. A study of the effects of hydrophobic and hydrophilic substrata on the colonization behavior of a marine bacterium, SW5, revealed major differences in the morphology of SW5 on these su...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.176.22.6900-6906.1994
更新日期:1994-11-01 00:00:00
abstract::Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.) and Guy P. Youmans. Effect of mycosuppressin on the respiration and growth of Mycobacterium tuberculosis. J. Bacteriol. 84:708-715. 1962.-A substance, called mycosuppressin, was found in the lungs of guinea pigs and rabbits vaccinated with BCG or...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.84.4.708-715.1962
更新日期:1962-10-01 00:00:00