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1.
BMC Public Health ; 23(1): 1697, 2023 09 02.
Article in English | MEDLINE | ID: mdl-37660119

ABSTRACT

BACKGROUND: Although physical activity interventions are frequently reported to be effective, long-term changes are needed to generate meaningful health benefits. There are criticisms that evaluations of physical activity interventions mostly report short-term outcomes and that these are often self-reported rather than measured objectively. This study therefore aimed to assess the long-term (at least 24 month) effectiveness of behavioural interventions on objectively measured physical activity. METHODS: We conducted a systematic review with a meta-analysis of effects on objectively measured physical activity. We searched: Cochrane CENTRAL, EMBASE, PsychInfo, CINAHL and Pubmed up to 10th January 2022. Studies were included if they were in English and included a physical intervention that assessed physical activity in the long-term (defined as at least 24 months). RESULTS: Eight studies with 8480 participants were identified with data suitable for meta-analysis. There was a significant effect of interventions on daily steps 24 months post baseline (four studies, SMD: 0.15, 95% CI: 0.02 to 0.28) with similar results at 36 to 48 months of follow up (four studies, SMD: 0.17, 95% CI: 0.07 to 0.27). There was a significant effect of interventions on moderate-to-vigorous physical activity 24 months post baseline (four studies, SMD: 0.18 95% CI: 0.07 to 0.29) and at 36 to 48 months (three studies, SMD: 0.16 95% CI: 0.09 to 0.23). The mean effect size was small. However, the changes in moderate-to-vigorous physical activity and steps per day were clinically meaningful in the best-performing studies. CONCLUSION: This review suggests that behavioural interventions can be effective in promoting small, but clinically meaningful increases in objectively measured physical activity for up to 48 months. There is therefore a need to develop interventions that can achieve greater increases in long-term physical activity with greater efficiency.


Subject(s)
Behavior Therapy , Exercise , Humans , Self Report
2.
J Clin Neurosci ; 94: 140-151, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34863429

ABSTRACT

BACKGROUND: Insertion of external ventricular drain (EVD) is one of the most common neurosurgical procedures performed worldwide. This is generally performed freehand, on the basis of anatomical landmarks. There is significant variability in the reported accuracy of freehand placement, lacking Level I evidence. We present the first meta-analysis of freehand EVD placement accuracy and technologies or techniques to enhance accuracy. METHODS: We report a systematic review of the Pubmed, Embase, and Cochrane Central databases according to MOOSE (Meta-analysis Of Observational Studies) guidelines. 37 studies were included for qualitative analysis and 19 studies (2983 cases) for quantitative analysis. RESULTS: There is substantial heterogeneity in the outcome measures used to report EVD placement accuracy. Of those nineteen studies reporting accuracy using the Kakarla grading system the mean rate of ideal ipsilateral frontal horn placement was 73% (standard deviation ±7%). The use of formal stereotaxic guidance is consistently reported to improve accuracy to >90%, although with variable outcome measures. However, the reported efficacy of other guidance devices or techniques is highly variable. The quality of studies directly comparing all existing non-stereotaxic devices with freehand EVD placement is poor and precludes any assertion of superiority to freehand insertion. CONCLUSIONS: We provide the first meta analysis of freehand placement accuracy. There is insufficient data to perform a meta-analysis of the relative efficacy of interventions to improve accuracy. Qualitative synthesis of reports of stereotaxic guidance is suggestive of higher accuracy than freehand placement.


Subject(s)
Drainage , Neurosurgical Procedures
3.
J Clin Neurosci ; 94: 65-69, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34863464

ABSTRACT

External ventricular drain (EVD) or ventriculostomy placement is one of the most common neurosurgical procedures performed worldwide and is associated with complications including haemorrhage, malposition and infection. Several authors have attempted to define an ideal trajectory for placement, and scalp-mounted guidance devices have been devised to exploit the theoretical ideal orthogonal trajectory from the scalp to the lateral ventricles. However, uptake has been limited due to lack of demonstrated superiority to freehand placement. Previous modelling studies have failed to include a true-to-life sample of patients undergoing EVD insertion and excluded cases with midline shift or non-hydrocephalus indications. Further, none have attempted to model the orthogonal insertion of EVD via actual burr holes placed by junior neurosurgical staff. In our report of 58 cases of frontal EVD insertion in a low-volume Australian neurosurgical unit freehand EVD insertion resulted in acceptable placement in the ipsilateral frontal horn in 62% of cases, any ventricle in 22%, and in eloquent or non-eloquent brain in 16% of cases. The modelled orthogonal trajectory from the same burr holes, using post-procedural computed tomography scans and the S8 Stealth Station (Medtronic), resulted in superior placement; 80% in the ipsilateral frontal horn and 20% contralateral (p = 0.007). There were no significant malpositions associated with the modelled trajectories. In our series, 18% of freehand catheters required multiple placement attempts. In conclusion, our data suggests that an orthogonal trajectory may result in improved EVD positioning compared to freehand placement.


Subject(s)
Drainage , Trephining , Australia , Cerebral Ventricles/diagnostic imaging , Cerebral Ventricles/surgery , Humans , Ventriculostomy
4.
Physiotherapy ; 111: 23-30, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33316865

ABSTRACT

BACKGROUND: Chronic musculoskeletal disorders are the second largest contributor to disability globally. Exercise is typically recommended by physiotherapists to manage symptoms. However, adherence to the prescribed exercise programme is often poor. Adjunctive digital interventions offer potential to enhance exercise adherence. OBJECTIVES: To review evidence on the effectiveness of digital interventions for improving exercise adherence in people with chronic musculoskeletal conditions. The study is reported in line with PRISMA guidance and was registered with PROSPERO (CRD42019124502). DATA SOURCES: MEDLINE, Embase and PsycInfo were searched using a comprehensive search strategy. The reference lists of all included papers and relevant systematic reviews identified during the search were scanned for relevant articles. STUDY APPRAISAL AND SYNTHESIS METHODS: Two researchers independently checked articles for inclusion and extracted data. RESULTS: The search returned a total of 4257 results of which five trials were included in the review and two studies were included in a random effects meta-analysis. There was no statistically significant difference in exercise adherence (SMD: 0.23; 95% CI: -0.10, 0.57). Studies that were not suitable for inclusion in the meta-analysis reported similar results. Heterogeneity of effects was high and study quality ranged from low to moderate. All of the meta-analysed data related to osteoarthritis of the hip and/or knee. CONCLUSION: We found no evidence that digital interventions enhance adherence to therapeutic exercise in patients with chronic musculoskeletal disorders. However, further, high quality research is required to draw definitive conclusions on their effectiveness and to identify key components that are associated with effectiveness. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42019124502.


Subject(s)
Chronic Pain , Musculoskeletal Pain , Exercise , Exercise Therapy , Humans
5.
Article in English | MEDLINE | ID: mdl-31010865

ABSTRACT

Pseudomonas aeruginosa is a Gram-negative opportunistic bacterial pathogen that can cause chronic lung infections in patients with cystic fibrosis (CF). The current preferred treatment for CF lung infections includes inhaled tobramycin (TOB); however, studies suggest TOB cannot effectively inhibit biofilm formation. Using an NIH small compounds drug library approved for safe use in humans, we identified rifaximin (RFX), a semisynthetic, rifamycin family, nonsystemic antibiotic that inhibits alginate production and growth in P. aeruginosa Inhibition of alginate production was further analyzed using the uronic acid carbazole assay and a promoter reporter assay that measures the transcription of the alginate biosynthetic operon. Compared to TOB, RFX significantly reduced alginate production in laboratory and CF sputum isolates of P. aeruginosa In addition, RFX showed a narrow range of MICs when measured with multidrug-resistant bacterial species of clinical relevance, synergistic activities with TOB or amikacin against clinical isolates, as well as reduction toward in vitro preformed biofilms. In C57BL/6 mice, penetration of nebulized TOB into the lungs was shown at a higher level than that of RFX. Further, in vivo assessment using a DBA/2 mouse lung infection model found increased survival rates with a single-dose treatment of nebulized RFX and decreased P. aeruginosa PAO1 bioburden with a multiple-dose treatment of RFX plus TOB. In addition, mice treated with a single exposure to dimethyl sulfoxide (DMSO), a solvent that dissolves RFX, showed no apparent toxicity. In summary, RFX may be used to supplement TOB inhalation therapy to increase efficacy against P. aeruginosa biofilm infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Pneumonia/drug therapy , Pseudomonas Infections/drug therapy , Pseudomonas aeruginosa/drug effects , Rifaximin/pharmacology , Tobramycin/pharmacology , Alginates/metabolism , Amikacin/pharmacology , Animals , Biofilms/drug effects , Cystic Fibrosis/microbiology , Disease Models, Animal , Female , Lung/drug effects , Lung/microbiology , Male , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Microbial Sensitivity Tests/methods , Pneumonia/microbiology , Pseudomonas Infections/microbiology , Sputum/microbiology
6.
Bull Entomol Res ; 107(4): 439-447, 2017 Aug.
Article in English | MEDLINE | ID: mdl-27974053

ABSTRACT

Cotesia urabae is a solitary larval endoparasitoid that was introduced into New Zealand in 2011 as a classical biological control agent against Uraba lugens. A detailed knowledge of its reproductive biology is required to optimize mass rearing efficiency. In this study, the courtship and mating behaviour of C. urabae is described and investigated from a series of experiments, conducted to understand the factors that influence male mating success. Cotesia urabae males exhibited a high attraction to virgin females but not mated females, whereas females showed no attraction to either virgin or mated males. Male mating success was highest in the presence of a male competitor. Also, the time to mate was shorter and copulation duration was longer when a male competitor was present. Larger male C. urabae had greater mating success than smaller males when paired together with a single female. This knowledge can now be utilized to improve mass rearing methods of C. urabae for the future.


Subject(s)
Sexual Behavior, Animal , Wasps , Animals , Body Size , Competitive Behavior , Female , Male
7.
Bioorg Med Chem Lett ; 26(4): 1305-9, 2016 Feb 15.
Article in English | MEDLINE | ID: mdl-26826023

ABSTRACT

Pseudomonas aeruginosa is a common biofilm-forming bacterial pathogen implicated in diseases of the lungs. The extracellular polymeric substances (EPS) of respiratory Pseudomonas biofilms are largely comprised of anionic molecules such as rhamnolipids and alginate that promote a mucoid phenotype. In this Letter, we examine the ability of negatively-charged fluoroquinolones to transverse the EPS and inhibit the growth of mucoid P. aeruginosa. Anionic fluoroquinolones were further compared with standard antibiotics via a novel microdiffusion assay to evaluate drug penetration through pseudomonal alginate and respiratory mucus from a patient with cystic fibrosis.


Subject(s)
Anti-Bacterial Agents/chemistry , Fluoroquinolones/chemistry , Pseudomonas aeruginosa/physiology , Anions/chemistry , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Fluoroquinolones/chemical synthesis , Fluoroquinolones/pharmacology , Microbial Sensitivity Tests
8.
Mol Microbiol ; 93(3): 415-25, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24913916

ABSTRACT

In Pseudomonas aeruginosa, alginate overproduction, also known as mucoidy, is negatively regulated by the transmembrane protein MucA, which sequesters the alternative sigma factor AlgU. MucA is degraded via a proteolysis pathway that frees AlgU from sequestration, activating alginate biosynthesis. Initiation of this pathway normally requires two signals: peptide sequences in unassembled outer-membrane proteins (OMPs) activate the AlgW protease, and unassembled lipopolysaccharides bind periplasmic MucB, releasing MucA and facilitating its proteolysis by activated AlgW. To search for novel alginate regulators, we screened a transposon library in the non-mucoid reference strain PAO1, and identified a mutant that confers mucoidy through overexpression of a protein encoded by the chaperone-usher pathway gene cupB5. CupB5-dependent mucoidy occurs through the AlgU pathway and can be reversed by overexpression of MucA or MucB. In the presence of activating OMP peptides, peptides corresponding to a region of CupB5 needed for mucoidy further stimulated AlgW cleavage of MucA in vitro. Moreover, the CupB5 peptide allowed OMP-activated AlgW cleavage of MucA in the presence of the MucB inhibitor. These results support a novel mechanism for conversion to mucoidy in which the proteolytic activity of AlgW and its ability to compete with MucB for MucA is mediated by independent peptide signals.


Subject(s)
Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/metabolism , Alginates , DNA Transposable Elements , Glucuronic Acid/biosynthesis , Hexuronic Acids , Molecular Chaperones/metabolism , Mutation , Protein Sorting Signals , Repressor Proteins/metabolism , Sigma Factor/metabolism
9.
J Vis Exp ; (85)2014 Mar 10.
Article in English | MEDLINE | ID: mdl-24637508

ABSTRACT

Pseudomonas aeruginosa is a Gram-negative, environmental bacterium with versatile metabolic capabilities. P. aeruginosa is an opportunistic bacterial pathogen which establishes chronic pulmonary infections in patients with cystic fibrosis (CF). The overproduction of a capsular polysaccharide called alginate, also known as mucoidy, promotes the formation of mucoid biofilms which are more resistant than planktonic cells to antibiotic chemotherapy and host defenses. Additionally, the conversion from the nonmucoid to mucoid phenotype is a clinical marker for the onset of chronic infection in CF. Alginate overproduction by P. aeruginosa is an endergonic process which heavily taxes cellular energy. Therefore, alginate production is highly regulated in P. aeruginosa. To better understand alginate regulation, we describe a protocol using the mini-himar1 transposon mutagenesis for the identification of novel alginate regulators in a prototypic strain PAO1. The procedure consists of two basic steps. First, we transferred the mini-himar1 transposon (pFAC) from host E. coli SM10/λpir into recipient P. aeruginosa PAO1 via biparental conjugation to create a high-density insertion mutant library, which were selected on Pseudomonas isolation agar plates supplemented with gentamycin. Secondly, we screened and isolated the mucoid colonies to map the insertion site through inverse PCR using DNA primers pointing outward from the gentamycin cassette and DNA sequencing. Using this protocol, we have identified two novel alginate regulators, mucE (PA4033) and kinB (PA5484), in strain PAO1 with a wild-type mucA encoding the anti-sigma factor MucA for the master alginate regulator AlgU (AlgT, σ(22)). This high-throughput mutagenesis protocol can be modified for the identification of other virulence-related genes causing change in colony morphology.


Subject(s)
DNA Transposable Elements , Mutagenesis, Insertional/methods , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/metabolism , Alginates , DNA-Binding Proteins/genetics , Glucuronic Acid/biosynthesis , Hexuronic Acids , Transposases/genetics
10.
Pathog Dis ; 70(2): 185-8, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24115673

ABSTRACT

In this study, we performed whole-genome complementation using a PAO1-derived cosmid library, coupled with in vitro transposon mutagenesis, to identify gene locus PA1494 as a novel inhibitor of alginate overproduction in P. aeruginosa strains possessing a wild-type mucA.


Subject(s)
Gene Expression Regulation, Bacterial , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Alginates , DNA Transposable Elements , Genetic Complementation Test , Glucuronic Acid/biosynthesis , Glucuronic Acid/genetics , Hexuronic Acids , Mutagenesis, Insertional
11.
Genome Announc ; 1(6)2013 Dec 12.
Article in English | MEDLINE | ID: mdl-24336371

ABSTRACT

The small envelope protein MucE and the sensor kinase KinB are a positive and negative alginate regulator, respectively. Here, we announce the draft genome sequences of the alginate-overproducing variants Pseudomonas aeruginosa PAO1-VE2 (PAO1 with constitutive expression of mucE) and PAO1-VE13 (PAO1 with kinB inactivated). Both mutants were generated from a transposon mutagenesis screen.

12.
Genome Announc ; 1(5)2013 Oct 10.
Article in English | MEDLINE | ID: mdl-24115549

ABSTRACT

A mutation in the mucA gene, which encodes a negative regulator of alginate production in Pseudomonas aeruginosa, is the main mechanism underlying the conversion to mucoidy in clinical isolates from patients with cystic fibrosis (CF). Here, we announce the draft genome sequence of the stable alginate-overproducing mucoid strain P. aeruginosa PAO581 with a mucA25 mutation, a derivative from the nonmucoid strains P. aeruginosa PAO381 and PAO1.

13.
Genome Announc ; 1(5)2013 Oct 10.
Article in English | MEDLINE | ID: mdl-24115552

ABSTRACT

Alginate overproduction by Pseudomonas aeruginosa, or mucoidy, plays an important role in the pathogenesis of chronic lung infections in cystic fibrosis (CF) patients. Here we report the draft genome sequence of a clinical isolate of mucoid P. aeruginosa strain C7447m from a CF patient with chronic lung infection.

14.
BMC Microbiol ; 13: 232, 2013 Oct 18.
Article in English | MEDLINE | ID: mdl-24138584

ABSTRACT

BACKGROUND: Alginate overproduction in P. aeruginosa, also referred to as mucoidy, is a poor prognostic marker for patients with cystic fibrosis (CF). We previously reported the construction of a unique mucoid strain which overexpresses a small envelope protein MucE leading to activation of the protease AlgW. AlgW then degrades the anti-sigma factor MucA thus releasing the alternative sigma factor AlgU/T (σ(22)) to initiate transcription of the alginate biosynthetic operon. RESULTS: In the current study, we mapped the mucE transcriptional start site, and determined that P(mucE) activity was dependent on AlgU. Additionally, the presence of triclosan and sodium dodecyl sulfate was shown to cause an increase in P(mucE) activity. It was observed that mucE-mediated mucoidy in CF isolates was dependent on both the size of MucA and the genotype of algU. We also performed shotgun proteomic analysis with cell lysates from the strains PAO1, VE2 (PAO1 with constitutive expression of mucE) and VE2ΔalgU (VE2 with in-frame deletion of algU). As a result, we identified nine algU-dependent and two algU-independent proteins that were affected by overexpression of MucE. CONCLUSIONS: Our data indicates there is a positive feedback regulation between MucE and AlgU. Furthermore, it seems likely that MucE may be part of the signal transduction system that senses certain types of cell wall stress to P. aeruginosa.


Subject(s)
Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Peptide Hydrolases/biosynthesis , Pseudomonas aeruginosa/genetics , Sigma Factor/metabolism , Transcription, Genetic , Alginates , Glucuronic Acid/biosynthesis , Hexuronic Acids , Promoter Regions, Genetic , Transcription Initiation Site
15.
PLoS One ; 8(8): e72329, 2013.
Article in English | MEDLINE | ID: mdl-23991093

ABSTRACT

Alginate overproduction, or mucoidy, plays an important role in the pathogenesis of P. aeruginosa lung infection in cystic fibrosis (CF). Mucoid strains with mucA mutations predominantly populate in chronically-infected patients. However, the mucoid strains can revert to nonmucoidy in vitro through suppressor mutations. We screened a mariner transposon library using CF149, a non-mucoid clinical isolate with a misssense mutation in algU (AlgU(A61V)). The wild type AlgU is a stress-related sigma factor that activates transcription of alginate biosynthesis. Three mucoid mutants were identified with transposon insertions that caused 1) an overexpression of AlgU(A61V), 2) an overexpression of the stringent starvation protein A (SspA), and 3) a reduced expression of the major sigma factor RpoD (σ(70)). Induction of AlgU(A61V) in trans caused conversion to mucoidy in CF149 and PAO1DalgU, suggesting that AlgU(A61V) is functional in activating alginate production. Furthermore, the level of AlgU(A61V) was increased in all three mutants relative to CF149. However, compared to the wild type AlgU, AlgU(A61V) had a reduced activity in promoting alginate production in PAO1ΔalgU. SspA and three other anti-σ(70) orthologues, P. aeruginosa AlgQ, E. coli Rsd, and T4 phage AsiA, all induced mucoidy, suggesting that reducing activity of RpoD is linked to mucoid conversion in CF149. Conversely, RpoD overexpression resulted in suppression of mucoidy in all mucoid strains tested, indicating that sigma factor competition can regulate mucoidy. Additionally, an RpoD-dependent promoter (PssrA ) was more active in non-mucoid strains than in isogenic mucoid variants. Altogether, our results indicate that the anti-σ(70) factors can induce conversion to mucoidy in P. aeruginosa CF149 with algU-suppressor mutation via modulation of RpoD.


Subject(s)
DNA-Directed RNA Polymerases/metabolism , Pseudomonas aeruginosa/metabolism , Sigma Factor/metabolism , Alginates , Blotting, Western , Cystic Fibrosis/complications , DNA Transposable Elements , Electrophoresis, Polyacrylamide Gel , Glucuronic Acid/biosynthesis , Hexuronic Acids , Humans , Mucus , Pseudomonas Infections/complications , Pseudomonas Infections/physiopathology , Pseudomonas aeruginosa/growth & development , Real-Time Polymerase Chain Reaction
16.
Antimicrob Agents Chemother ; 57(10): 4707-16, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23856776

ABSTRACT

Antimicrobial peptides (AMPs) can cause lysis of target bacteria by directly inserting themselves into the lipid bilayer. This killing mechanism confounds the identification of the intracellular targets of AMPs. To circumvent this, we used a shuttle vector containing the inducible expression of a human cathelicidin-related AMP, LL-37, to examine its effect on Escherichia coli TOP10 under aerobic and anaerobic growth conditions. Induction of LL-37 caused growth inhibition and alteration in cell morphology to a filamentous phenotype. Further examination of the E. coli cell division protein FtsZ revealed that LL-37 did not interact with FtsZ. Moreover, intracellular expression of LL-37 results in the enhanced production of reactive oxygen species (ROS), causing lethal membrane depolarization under aerobic conditions. Additionally, the membrane permeability was increased after intracellular expression of LL37 under both aerobic and anaerobic conditions. Transcriptomic analysis revealed that intracellular LL-37 mainly affected the expression of genes related to energy production and carbohydrate metabolism. More specifically, genes related to oxidative phosphorylation under both aerobic and anaerobic growth conditions were affected. Collectively, our current study demonstrates that intracellular expression of LL-37 in E. coli can inhibit growth under aerobic and anaerobic conditions. While we confirmed that the generation of ROS is a bactericidal mechanism for LL-37 under aerobic growth conditions, we also found that the intracellular accumulation of cationic LL-37 influences the redox and ion status of the cells under both growth conditions. These data suggest that there is a new AMP-mediated bacterial killing mechanism that targets energy metabolism.


Subject(s)
Cathelicidins/metabolism , Escherichia coli/metabolism , Aerobiosis , Anaerobiosis , Antimicrobial Cationic Peptides , Escherichia coli/genetics , Escherichia coli/growth & development , Oxidation-Reduction , Reactive Oxygen Species/metabolism
17.
Microbiologyopen ; 2(3): 459-70, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23533140

ABSTRACT

Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establishment of chronic lung infections in individuals with cystic fibrosis. Expression of the alginate biosynthetic operon is primarily controlled by the alternative sigma factor AlgU (AlgT/σ(22) ). In a nonmucoid strain, AlgU is sequestered by the transmembrane antisigma factor MucA to the cytoplasmic membrane. AlgU can be released from MucA via regulated intramembrane proteolysis by proteases AlgW and MucP causing the conversion to mucoidy. Pseudomonas aeruginosa strain PAO579, a derivative of the nonmucoid strain PAO1, is mucoid due to an unidentified mutation (muc-23). Using whole genome sequencing, we identified 16 nonsynonymous and 15 synonymous single nucleotide polymorphisms (SNP). We then identified three tandem single point mutations in the pilA gene (PA4525), as the cause of mucoidy in PAO579. These tandem mutations generate a premature stop codon resulting in a truncated version of PilA (PilA(108) ), with a C-terminal motif of phenylalanine-threonine-phenylalanine (FTF). Inactivation of pilA(108) confirmed it was required for mucoidy. Additionally, algW and algU were also required for mucoidy of PAO579. Western blot analysis indicated that MucA was less stable in PAO579 than nonmucoid PAO1 or PAO381. The mucoid phenotype and high PalgU and PalgD promoter activities of PAO579 require pilA(108) , algW, algU, and rpoN encoding the alternative sigma factor σ(54) . We also observed that RpoN regulates expression of algW and pilA in PAO579. Together, these results suggest that truncation in type IV pilin in P. aeruginosa strain PAO579 can induce mucoidy through an AlgW/AlgU-dependent pathway.


Subject(s)
Alginates/metabolism , Fimbriae Proteins/genetics , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/metabolism , Sequence Deletion , DNA Mutational Analysis , Gene Knockout Techniques , Genome, Bacterial , Glucuronic Acid/metabolism , Hexuronic Acids/metabolism , Point Mutation , Polymorphism, Single Nucleotide , Sequence Analysis, DNA
18.
J Bacteriol ; 194(23): 6617, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23144378

ABSTRACT

Pseudomonas aeruginosa is an opportunistic pathogen that establishes a chronic lung infection in individuals afflicted with cystic fibrosis. Here, we announce the draft genome of P. aeruginosa strain PAO579, an alginate-overproducing derivative of strain PAO381.


Subject(s)
DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Genome, Bacterial , Pseudomonas aeruginosa/genetics , Sequence Analysis, DNA , Alginates/metabolism , Glucuronic Acid/metabolism , Hexuronic Acids/metabolism , Molecular Sequence Data , Pseudomonas aeruginosa/isolation & purification , Pseudomonas aeruginosa/metabolism
19.
Mol Microbiol ; 81(2): 554-70, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21631603

ABSTRACT

Alginate overproduction by P. aeruginosa strains, also known as mucoidy, is associated with chronic lung infections in cystic fibrosis (CF). It is not clear how alginate induction occurs in the wild-type (wt) mucA strains. When grown on Pseudomonas isolation agar (PIA), P. aeruginosa strains PAO1 and PA14 are non-mucoid, producing minimal amounts of alginate. Here we report the addition of ammonium metavanadate (AMV), a phosphatase inhibitor, to PIA (PIA-AMV) induced mucoidy in both these laboratory strains and early lung colonizing non-mucoid isolates with a wt mucA. This phenotypic switch was reversible depending on the availability of vanadate salts and triclosan, a component of PIA. Alginate induction in PAO1 on PIA-AMV was correlated with increased proteolytic degradation of MucA, and required envelope proteases AlgW or MucP, and a two-component phosphate regulator, PhoP. Other changes included the addition of palmitate to lipid A, a phenotype also observed in chronic CF isolates. Proteomic analysis revealed the upregulation of stress chaperones, which was confirmed by increased expression of the chaperone/protease MucD. Altogether, these findings suggest a model of alginate induction and the PIA-AMV medium may be suitable for examining early lung colonization phenotypes in CF before the selection of the mucA mutants.


Subject(s)
Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial/drug effects , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/metabolism , Triclosan/metabolism , Vanadates/metabolism , Alginates , Glucuronic Acid/biosynthesis , Hexuronic Acids , Proteome/analysis
20.
J Econ Entomol ; 99(3): 780-9, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16813312

ABSTRACT

The leaf skeletonizer Uraba lugens Walker (Lepidoptera: Nolidae), an Australian species, locally known as "gumleaf skeletonizer", is well established in New Zealand. This insect has the potential to become a serious pest of forestry and amenity eucalypts (Eucalyptus spp.) and is the focus of a long-term management program. The use of synthetic chemical or biological insecticides is one possible control method within an integrated control program. A series of dose-response trials were conducted using laboratory bioassays to test the efficacy of several insecticides against U. lugens: pyrethroids, spinosad, Bacillus thuringiensis kurstaki Berliner (Btk) and an insect growth regulator, Mimic. Pyrethroids and spinosad proved highly effective against U. lugens larvae, achieving 100% mortality after 3-6-d exposure. The performance of Btk was lower against gregarious skeletonizing larvae compared with solitary chewing larvae. When good coverage of the target foliage is achieved, >90% mortality is possible with Btk. Mimic performed poorly against U. lugens compared with other insecticides tested (<60% mortality). The Eucalyptus species on which larvae were feeding significantly altered insecticide efficacy. Treatments applied to Eucalyptus nitens (Deane & Maiden) Maiden had reduced efficacy compared with E. cinerea F. Muell. ex Benth. or E. fastigata Deane & Maiden. Cooler temperatures also reduced insecticide efficacy, presumably by decreasing movement and food consumption by U. lugens. Recommendations on spray applications to control U. lugens in New Zealand are given.


Subject(s)
Eucalyptus/parasitology , Insecticides , Moths , Animals , Bacillus thuringiensis , Drug Combinations , Host-Parasite Interactions , Hydrazines , Juvenile Hormones , Macrolides , Pest Control, Biological , Pyrethrins , Temperature
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