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1.
Nat Commun ; 12(1): 4786, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34373455

RESUMO

Salmonella enterica serovar 4,[5],12:i:- (Salmonella 4,[5],12:i:-) is a monophasic variant of Salmonella Typhimurium that has emerged as a global cause of multidrug resistant salmonellosis. We used Bayesian phylodynamics, genomic epidemiology, and phenotypic characterization to describe the emergence and evolution of Salmonella 4,[5],12:i:- in Australia. We show that the interruption of the genetic region surrounding the phase II flagellin, FljB, causing a monophasic phenotype, represents a stepwise evolutionary event through the accumulation of mobile resistance elements with minimal impairment to bacterial fitness. We identify three lineages with different population dynamics and discrete antimicrobial resistance profiles emerged, likely reflecting differential antimicrobial selection pressures. Two lineages are associated with travel to South-East Asia and the third lineage is endemic to Australia. Moreover antimicrobial-resistant Salmonella 4,[5],12:i- lineages efficiently infected and survived in host phagocytes and epithelial cells without eliciting significant cellular cytotoxicity, suggesting a suppression of host immune response that may facilitate the persistence of Salmonella 4,[5],12:i:-.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Evolução Molecular , Salmonella enterica/classificação , Salmonella enterica/genética , Sorogrupo , Antibacterianos/farmacologia , Austrália , Teorema de Bayes , Linhagem Celular , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Flagelina/genética , Humanos , Imunidade , Metais Pesados/farmacologia , Filogenia , Salmonella enterica/efeitos dos fármacos , Salmonella typhimurium , Células THP-1 , Sequenciamento Completo do Genoma
2.
Cell Rep ; 35(6): 109108, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33961822

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses subgenomic RNA (sgRNA) to produce viral proteins for replication and immune evasion. We apply long-read RNA and cDNA sequencing to in vitro human and primate infection models to study transcriptional dynamics. Transcription-regulating sequence (TRS)-dependent sgRNA upregulates earlier in infection than TRS-independent sgRNA. An abundant class of TRS-independent sgRNA consisting of a portion of open reading frame 1ab (ORF1ab) containing nsp1 joins to ORF10, and the 3' untranslated region (UTR) upregulates at 48 h post-infection in human cell lines. We identify double-junction sgRNA containing both TRS-dependent and -independent junctions. We find multiple sites at which the SARS-CoV-2 genome is consistently more modified than sgRNA and that sgRNA modifications are stable across transcript clusters, host cells, and time since infection. Our work highlights the dynamic nature of the SARS-CoV-2 transcriptome during its replication cycle.


Assuntos
COVID-19/genética , SARS-CoV-2/genética , Transcrição Genética/genética , Animais , Células CACO-2 , Linhagem Celular , Chlorocebus aethiops , Epigênese Genética , Genoma Viral/genética , Humanos , Evasão da Resposta Imune , Fases de Leitura Aberta , RNA Viral/genética , Transcriptoma , Células Vero , Proteínas Virais/genética
3.
J Clin Microbiol ; 59(5)2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33658263

RESUMO

Resistance-guided therapy (RGT) for gonorrhea may reduce unnecessary use of broad-spectrum antibiotics. When reflexed from the Aptima Combo 2 assay, the ResistancePlus GC assay demonstrated 94.8% sensitivity and 100.0% specificity for Neisseria gonorrhoeae detection. Of the 379 concordant N. gonorrhoeae-positive samples, 86.8% were found to possess the gyrA S91F mutation, which was highly predictive for ciprofloxacin resistance and stable across 3,144 publicly available N. gonorrhoeae genomes. Our work supports the feasibility of implementing RGT for gonorrhea into routine molecular workflows.


Assuntos
Gonorreia , Neisseria gonorrhoeae , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana , Gonorreia/diagnóstico , Gonorreia/tratamento farmacológico , Humanos , Testes de Sensibilidade Microbiana , Neisseria gonorrhoeae/genética , Reflexo
4.
Artigo em Inglês | MEDLINE | ID: mdl-33593834

RESUMO

Topical antibiotic preparations, such as fusidic acid (FA) or mupirocin, are used in the prevention and treatment of superficial skin infections caused by staphylococci. Previous genomic epidemiology work has suggested an association between the widespread use of topical antibiotics and the emergence of methicillin resistant Staphylococcus aureus in some settings. In this study, we provide experimental proof of co-selection for multidrug resistance in S. aureus following exposure to FA or mupirocin. Through targeted mutagenesis and phenotypic analyses, we confirmed that fusC carriage confers resistance to FA, and mupA carriage confers high-level resistance to mupirocin in multiple S. aureus genetic backgrounds. In vitro experiments demonstrated that carriage of fusC and mupA confer a competitive advantage in the presence of sub-inhibitory concentrations of FA and mupirocin, respectively. Further, we used a porcine skin colonisation model to show that clinically relevant concentrations of topical antibiotics can co-select for presence of unrelated antimicrobial resistance determinants, such as mecA, blaZ, and qacA, in fusC or mupA harbouring S. aureus These findings provide valuable insights on the role of acquired FA or mupirocin resistance in co-selecting for broader antibiotic resistance in S. aureus, prompting greater need for judicious use of topical antibiotics.

5.
Nat Commun ; 11(1): 4126, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807804

RESUMO

Neisseria gonorrhoeae is an urgent public health threat due to rapidly increasing incidence and antibiotic resistance. In contrast with the trend of increasing resistance, clinical isolates that have reverted to susceptibility regularly appear, prompting questions about which pressures compete with antibiotics to shape gonococcal evolution. Here, we used genome-wide association to identify loss-of-function (LOF) mutations in the efflux pump mtrCDE operon as a mechanism of increased antibiotic susceptibility and demonstrate that these mutations are overrepresented in cervical relative to urethral isolates. This enrichment holds true for LOF mutations in another efflux pump, farAB, and in urogenitally-adapted versus typical N. meningitidis, providing evidence for a model in which expression of these pumps in the female urogenital tract incurs a fitness cost for pathogenic Neisseria. Overall, our findings highlight the impact of integrating microbial population genomics with host metadata and demonstrate how host environmental pressures can lead to increased antibiotic susceptibility.


Assuntos
Proteínas de Bactérias/metabolismo , Colo do Útero/microbiologia , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/genética , Animais , Proteínas de Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Feminino , Regulação Bacteriana da Expressão Gênica , Estudo de Associação Genômica Ampla , Humanos , Testes de Sensibilidade Microbiana , Mutação/genética , Neisseria gonorrhoeae/metabolismo , Óperon/genética , Regiões Promotoras Genéticas/genética
6.
Elife ; 92020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32602459

RESUMO

Genotype-based diagnostics for antibiotic resistance represent a promising alternative to empiric therapy, reducing inappropriate antibiotic use. However, because such assays infer resistance based on known genetic markers, their utility will wane with the emergence of novel resistance. Maintenance of these diagnostics will therefore require surveillance to ensure early detection of novel resistance variants, but efficient strategies to do so remain undefined. We evaluate the efficiency of targeted sampling approaches informed by patient and pathogen characteristics in detecting antibiotic resistance and diagnostic escape variants in Neisseria gonorrhoeae, a pathogen associated with a high burden of disease and antibiotic resistance and the development of genotype-based diagnostics. We show that patient characteristic-informed sampling is not a reliable strategy for efficient variant detection. In contrast, sampling informed by pathogen characteristics, such as genomic diversity and genomic background, is significantly more efficient than random sampling in identifying genetic variants associated with resistance and diagnostic escape.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Genoma Bacteriano , Gonorreia/microbiologia , Neisseria gonorrhoeae/efeitos dos fármacos , Gonorreia/tratamento farmacológico , Neisseria gonorrhoeae/genética
7.
mSystems ; 5(3)2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32430409

RESUMO

F420 is a low-potential redox cofactor used by diverse bacteria and archaea. In mycobacteria, this cofactor has multiple roles, including adaptation to redox stress, cell wall biosynthesis, and activation of the clinical antitubercular prodrugs pretomanid and delamanid. A recent biochemical study proposed a revised biosynthesis pathway for F420 in mycobacteria; it was suggested that phosphoenolpyruvate served as a metabolic precursor for this pathway, rather than 2-phospholactate as long proposed, but these findings were subsequently challenged. In this work, we combined metabolomic, genetic, and structural analyses to resolve these discrepancies and determine the basis of F420 biosynthesis in mycobacterial cells. We show that, in whole cells of Mycobacterium smegmatis, phosphoenolpyruvate rather than 2-phospholactate stimulates F420 biosynthesis. Analysis of F420 biosynthesis intermediates present in M. smegmatis cells harboring genetic deletions at each step of the biosynthetic pathway confirmed that phosphoenolpyruvate is then used to produce the novel precursor compound dehydro-F420-0. To determine the structural basis of dehydro-F420-0 production, we solved high-resolution crystal structures of the enzyme responsible (FbiA) in apo-, substrate-, and product-bound forms. These data show the essential role of a single divalent cation in coordinating the catalytic precomplex of this enzyme and demonstrate that dehydro-F420-0 synthesis occurs through a direct substrate transfer mechanism. Together, these findings resolve the biosynthetic pathway of F420 in mycobacteria and have significant implications for understanding the emergence of antitubercular prodrug resistance.IMPORTANCE Mycobacteria are major environmental microorganisms and cause many significant diseases, including tuberculosis. Mycobacteria make an unusual vitamin-like compound, F420, and use it to both persist during stress and resist antibiotic treatment. Understanding how mycobacteria make F420 is important, as this process can be targeted to create new drugs to combat infections like tuberculosis. In this study, we show that mycobacteria make F420 in a way that is different from other bacteria. We studied the molecular machinery that mycobacteria use to make F420, determining the chemical mechanism for this process and identifying a novel chemical intermediate. These findings also have clinical relevance, given that two new prodrugs for tuberculosis treatment are activated by F420.

8.
Med J Aust ; 212(10): 459-462, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32237278

RESUMO

OBJECTIVES: To describe the first isolation and sequencing of SARS-CoV-2 in Australia and rapid sharing of the isolate. SETTING: SARS-CoV-2 was isolated from a 58-year-old man from Wuhan, China who arrived in Melbourne on 19 January 2020 and was admitted to the Monash Medical Centre, Melbourne from the emergency department on 24 January 2020 with fever, cough, and progressive dyspnoea. MAJOR OUTCOMES: Clinical course and laboratory features of the first reported case of COVID-19 (the illness caused by SARS-CoV-2) in Australia; isolation, whole genome sequencing, imaging, and rapid sharing of virus from the patient. RESULTS: A nasopharyngeal swab and sputum collected when the patient presented to hospital were each positive for SARS-CoV-2 (reverse transcription polymerase chain reaction). Inoculation of Vero/hSLAM cells with material from the nasopharyngeal swab led to the isolation of SARS-CoV-2 virus in culture. Electron microscopy of the supernatant confirmed the presence of virus particles with morphology characteristic of viruses of the family Coronaviridae. Whole genome sequencing of the viral isolate and phylogenetic analysis indicated the isolate exhibited greater than 99.99% sequence identity with other publicly available SARS-CoV-2 genomes. Within 24 hours of isolation, the first Australian SARS-CoV-2 isolate was shared with local and overseas reference laboratories and major North American and European culture collections. CONCLUSIONS: The ability to rapidly identify, propagate, and internationally share our SARS-CoV-2 isolate is an important step in collaborative scientific efforts to deal effectively with this international public health emergency by developing better diagnostic procedures, vaccine candidates, and antiviral agents.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/genética , Disseminação de Informação/métodos , Isolamento de Pacientes/métodos , Pneumonia Viral/genética , Austrália , COVID-19 , Infecções por Coronavirus/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/diagnóstico , SARS-CoV-2 , Sequenciamento Completo do Genoma
9.
mSphere ; 5(2)2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32188750

RESUMO

Globally, more antimicrobials are used in food-producing animals than in humans, and the extensive use of medically important human antimicrobials poses a significant public health threat in the face of rising antimicrobial resistance (AMR). The development of novel ionophores, a class of antimicrobials used exclusively in animals, holds promise as a strategy to replace or reduce essential human antimicrobials in veterinary practice. PBT2 is a zinc ionophore with recently demonstrated antibacterial activity against several Gram-positive pathogens, although the underlying mechanism of action is unknown. Here, we investigated the bactericidal mechanism of PBT2 in the bovine mastitis-causing pathogen, Streptococcus uberis In this work, we show that PBT2 functions as a Zn2+/H+ ionophore, exchanging extracellular zinc for intracellular protons in an electroneutral process that leads to cellular zinc accumulation. Zinc accumulation occurs concomitantly with manganese depletion and the production of reactive oxygen species (ROS). PBT2 inhibits the activity of the manganese-dependent superoxide dismutase, SodA, thereby impairing oxidative stress protection. We propose that PBT2-mediated intracellular zinc toxicity in S. uberis leads to lethality through multiple bactericidal mechanisms: the production of toxic ROS and the impairment of manganese-dependent antioxidant functions. Collectively, these data show that PBT2 represents a new class of antibacterial ionophores capable of targeting bacterial metal ion homeostasis and cellular redox balance. We propose that this novel and multitarget mechanism of PBT2 makes the development of cross-resistance to medically important antimicrobials unlikely.IMPORTANCE More antimicrobials are used in food-producing animals than in humans, and the extensive use of medically important human antimicrobials poses a significant public health threat in the face of rising antimicrobial resistance. Therefore, the elimination of antimicrobial crossover between human and veterinary medicine is of great interest. Unfortunately, the development of new antimicrobials is an expensive high-risk process fraught with difficulties. The repurposing of chemical agents provides a solution to this problem, and while many have not been originally developed as antimicrobials, they have been proven safe in clinical trials. PBT2, a zinc ionophore, is an experimental therapeutic that met safety criteria but failed efficacy checkpoints against both Alzheimer's and Huntington's diseases. It was recently found that PBT2 possessed potent antimicrobial activity, although the mechanism of bacterial cell death is unresolved. In this body of work, we show that PBT2 has multiple mechanisms of antimicrobial action, making the development of PBT2 resistance unlikely.


Assuntos
Antibacterianos/farmacologia , Clioquinol/análogos & derivados , Ionóforos/farmacologia , Streptococcus/efeitos dos fármacos , Zinco/metabolismo , Animais , Bovinos , Clioquinol/farmacologia , Feminino , Mastite Bovina/microbiologia , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/antagonistas & inibidores
10.
J Med Microbiol ; 69(3): 478-486, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31935181

RESUMO

Introduction. Pseudomonas syringae pv. actinidiae (Psa) has emerged as a major bacterial pathogen of kiwifruit cultivation throughout the world.Aim. We aim to introduce a CRISPR-Cas9 system, a commonly used genome editing tool, into Psa. The protocols may also be useful in other Pseudomonas species.Methodology. Using standard molecular biology techniques, we modified plasmid pCas9, which carries the CRISPR-Cas9 sequences from Streptococcus pyogenes, for use in Psa. The final plasmid, pJH1, was produced in a series of steps and is maintained with selection in both Escherichia coli and Psa.Results. We have constructed plasmids carrying a CRISPR-Cas9 system based on that of S. pyogenes, which can be maintained, under selection, in Psa. We have shown that the gene targeting capacity of the CRISPR-Cas9 system is active and that the Cas9 protein is able to cleave the targeted sites. The Cas9 was directed to several different sites in the P. syringae genome. Using Cas9 we have generated Psa transformants that no longer carry the native plasmid present in Psa, and other transformants that lack the integrative, conjugative element, Pac_ICE1. Targeting of a specific gene, a chromosomal non-ribosomal peptide synthetase, led to gene knockouts with the transformants having deletions encompassing the target site.Conclusion. We have constructed shuttle plasmids carrying a CRISPR-Cas9 system that are maintained in both E. coli and P. syringae pv. actinidiae. We have used this gene editing system to eliminate features of the accessory genome (plasmids or ICEs) from Psa and to target a single chromosomal gene.


Assuntos
Sistemas CRISPR-Cas/fisiologia , Pseudomonas syringae/fisiologia , Actinidia/microbiologia , Sistemas CRISPR-Cas/genética , Escherichia coli/fisiologia , Frutas/microbiologia , Deleção de Genes , Técnicas de Inativação de Genes , Marcação de Genes , Engenharia Genética , Peptídeo Sintases/genética , Plasmídeos , Pseudomonas syringae/genética , Análise de Sequência de DNA , Streptococcus pyogenes/fisiologia , Sequenciamento Completo do Genoma
11.
J Lipid Res ; 61(3): 432-444, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31806727

RESUMO

Plasma lipoprotein (a) [Lp(a)] levels are largely determined by variation in the LPA gene, which codes for apo(a). Genome-wide association studies (GWASs) have identified nonsynonymous variants in LPA that associate with low Lp(a) levels, although their effect on apo(a) function is unknown. We investigated two such variants, R990Q and R1771C, which were present in four null Lp(a) individuals, for structural and functional effects. Sequence alignments showed the R990 and R1771 residues to be highly conserved and homologous to each other and to residues associated with plasminogen deficiency. Structural modeling showed both residues to make several polar contacts with neighboring residues that would be ablated on substitution. Recombinant expression of the WT and R1771C apo(a) in liver and kidney cells showed an abundance of an immature form for both apo(a) proteins. A mature form of apo(a) was only seen with the WT protein. Imaging of the recombinant apo(a) proteins in conjunction with markers of the secretory pathway indicated a poor transit of R1771C into the Golgi. Furthermore, the R1771C mutant displayed a glycosylation pattern consistent with ER, but not Golgi, glycosylation. We conclude that R1771 and the equivalent R990 residue facilitate correct folding of the apo(a) kringle structure and mutations at these positions prevent the proper folding required for full maturation and secretion. To our knowledge, this is the first example of nonsynonymous variants in LPA being causative of a null Lp(a) phenotype.


Assuntos
Apoproteína(a)/genética , Lipoproteína(a)/genética , Plasminogênio/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto , Idoso , Alelos , Linhagem Celular Tumoral , Estudos de Coortes , Humanos , Lipoproteína(a)/sangue , Masculino , Pessoa de Meia-Idade , Mutação , Plasminogênio/deficiência
12.
Nat Commun ; 10(1): 3988, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488838

RESUMO

Whole genome sequencing (WGS) has been used to investigate transmission of Neisseria gonorrhoeae, but to date, most studies have not combined genomic data with detailed information on sexual behaviour to define the extent of transmission across population risk groups (bridging). Here, through combined epidemiological and genomic analysis of 2,186N. gonorrhoeae isolates from Australia, we show widespread transmission of N. gonorrhoeae within and between population groups. We describe distinct transmission clusters associated with men who have sex with men (MSM) and heterosexuals, and men who have sex with men and women (MSMW) are identified as a possible bridging population between these groups. Further, the study identifies transmission of N. gonorrhoeae between HIV-positive and HIV-negative individuals receiving pre-exposure prophylaxis (PrEP). Our data highlight several groups that can be targeted for interventions aimed at improving gonorrhoea control, including returning travellers, sex workers, and PrEP users.


Assuntos
Gonorreia/tratamento farmacológico , Gonorreia/epidemiologia , Infecções por HIV/epidemiologia , Neisseria gonorrhoeae/genética , Profilaxia Pré-Exposição , Comportamento Sexual , Sequenciamento Completo do Genoma , Adulto , Feminino , Gonorreia/transmissão , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Humanos , Masculino , Fatores de Risco , Profissionais do Sexo , Parceiros Sexuais , Minorias Sexuais e de Gênero , Vitória , Adulto Jovem
13.
Appl Environ Microbiol ; 85(13)2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31028029

RESUMO

Enterococcus faecalis and Enterococcus faecium are human and animal gut commensals. Vancomycin-resistant enterococci (VRE) are important opportunistic pathogens with limited treatment options. Historically, the glycopeptide antibiotics vancomycin and avoparcin selected for the emergence of vancomycin resistance in human and animal isolates, respectively, resulting in global cessation of avoparcin use between 1997 and 2000. To better understand human- and animal-associated VRE strains in the postavoparcin era, we sequenced the genomes of 231 VRE isolates from New Zealand (NZ; 75 human clinical, 156 poultry) cultured between 1998 and 2009. E. faecium lineages and their antibiotic resistance carriage patterns strictly delineated between agricultural and human reservoirs, with bacitracin resistance ubiquitous in poultry but absent in clinical E. faecium strains. In contrast, one E. faecalis lineage (ST108) predominated in both poultry and human isolates in the 3 years following avoparcin discontinuation. Both phylogenetic and antimicrobial susceptibility (i.e., ubiquitous bacitracin resistance in both poultry and clinical ST108 isolates) analyses suggest an agricultural origin for the ST108 lineage. VRE isolate resistomes were carried on multiple, heterogeneous plasmids. In some isolate genomes, bacitracin, erythromycin, and vancomycin resistance elements were colocalized, indicating multiple potentially linked selection mechanisms.IMPORTANCE Historical antimicrobial use in NZ agriculture has driven the evolution of ST108, a VRE lineage carrying a range of clinically relevant antimicrobial resistances. The persistence of this lineage in NZ for over a decade indicates that coselection may be an important stabilizing mechanism for its persistence.


Assuntos
Antibacterianos/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Resistência a Vancomicina/genética , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Vancomicina/farmacologia , Enterococcus faecalis/classificação , Enterococcus faecalis/genética , Enterococcus faecium/classificação , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/genética , Testes de Sensibilidade Microbiana , Nova Zelândia , Enterococos Resistentes à Vancomicina/classificação , Enterococos Resistentes à Vancomicina/genética
14.
Artigo em Inglês | MEDLINE | ID: mdl-30637393

RESUMO

We present here the complete genome sequence of M228, a Chinese biovar 3 strain of Pseudomonas syringae pv. actinidiae, a bacterial pathogen of kiwifruit. A comparison of the insertion sequence (IS) profile of M228 with that of ICMP18708, a New Zealand isolate of P. syringae pv. actinidiae, provided insight into the evolutionary history of IS elements within biovar 3.

15.
Artigo em Inglês | MEDLINE | ID: mdl-30533874

RESUMO

Carbapenem-resistant Pseudomonas aeruginosa is defined as a "critical" priority pathogen for the development of new antibiotics. Here we report the complete genome sequence of an extensively drug-resistant, Verona integron-encoded metallo-ß-lactamase-expressing isolate belonging to the high-risk sequence type 233.

16.
Sci Rep ; 8(1): 10915, 2018 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30026612

RESUMO

The modern pandemic of the bacterial kiwifruit pathogen Pseudomonas syringae pv actinidiae (Psa) is caused by a particular Psa lineage. To better understand the genetic basis of the virulence of this lineage, we compare the completely assembled genome of a pandemic New Zealand strain with that of the Psa type strain first isolated in Japan in 1983. Aligning the two genomes shows numerous translocations, constrained so as to retain the appropriate orientation of the Architecture Imparting Sequences (AIMs). There are several large horizontally acquired regions, some of which include Type I, Type II or Type III restriction systems. The activity of these systems is reflected in the methylation patterns of the two strains. The pandemic strain carries an Integrative Conjugative Element (ICE) located at a tRNA-Lys site. Two other complex elements are also present at tRNA-Lys sites in the genome. These elements are derived from ICE but have now acquired some alternative secretion function. There are numerous types of mobile element in the two genomes. Analysis of these elements reveals no evidence of recombination between the two Psa lineages.


Assuntos
Genoma Bacteriano , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Pseudomonas syringae/patogenicidade , Fatores de Virulência/genética , Actinidia/microbiologia , Evolução Molecular , Transferência Genética Horizontal , Japão , Metilação , Nova Zelândia , Pandemias , Doenças das Plantas/microbiologia , Pseudomonas syringae/genética , RNA de Transferência/genética
17.
Genome Announc ; 6(9)2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29496837

RESUMO

Streptococcus uberis forms part of the native microbiota of cattle and is able to opportunistically infect the mammary gland; as such, it is a leading cause of bovine mastitis globally. Here, we report the complete genome sequence of S. uberis NZ01, isolated in New Zealand from a cow with a clinical case of bovine mastitis.

18.
Mol Microbiol ; 107(2): 198-213, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29134701

RESUMO

Glutamate racemase (MurI) has been proposed as a target for anti-tuberculosis drug development based on the inability of ΔmurI mutants of Mycobacterium smegmatis to grow in the absence of d-glutamate. In this communication, we identify ΔmurI suppressor mutants that are detected during prolonged incubation. Whole genome sequencing of these ΔmurI suppressor mutants identified the presence of a SNP, located in the promoter region of MSMEG_5795. RT-qPCR and transcriptional fusion analyses revealed that the ΔmurI suppressor mutant overexpressed MSMEG_5795 14-fold compared to the isogenic wild-type. MSMEG_5795, which is annotated as 4-amino-4-deoxychorismate lyase (ADCL) but which also has homology to d-amino acid transaminase (d-AAT), was expressed, purified and found to have d-AAT activity and to be capable of producing d-glutamate from d-alanine. Consistent with its d-amino acid transaminase function, overexpressed MSMEG_5795 is able to complement both ΔmurI deletion mutants and alanine racemase (Δalr) deletion mutants, thus confirming a multifunctional role for this enzyme in M. smegmatis.


Assuntos
Isomerases de Aminoácido/metabolismo , D-Alanina Transaminase/metabolismo , Mycobacterium smegmatis/enzimologia , Oxo-Ácido-Liases/metabolismo , Alanina/metabolismo , Alanina Racemase/genética , Alanina Racemase/metabolismo , Isomerases de Aminoácido/genética , Sequência de Bases/genética , D-Alanina Transaminase/química , D-Alanina Transaminase/genética , Deleção de Genes , Ácido Glutâmico/metabolismo , Mycobacterium smegmatis/genética , Oxo-Ácido-Liases/química , Oxo-Ácido-Liases/genética , Regiões Promotoras Genéticas , Supressão Genética , Sequenciamento Completo do Genoma
19.
Genome Announc ; 5(50)2017 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-29242227

RESUMO

We present the first complete genome sequence of a copper-resistant biovar 5 strain of a bacterial pathogen of kiwifruit, Pseudomonas syringae pv. actinidiae. Comparison with the genome sequence of a copper-sensitive biovar 5 isolate indicates that copper resistance is encoded on a plasmid.

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