scholarly journals Direct Glutaminyl-tRNA Biosynthesis and Indirect Asparaginyl-tRNA Biosynthesis in Pseudomonas aeruginosa PAO1

2004 ◽  
Vol 186 (3) ◽  
pp. 767-776 ◽  
Author(s):  
Pierre-Marie Akochy ◽  
Dominic Bernard ◽  
Paul H. Roy ◽  
Jacques Lapointe
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Genomic Sequence ◽  
Multidrug Resistant ◽  
Open Reading Frames ◽  
Indirect Pathway ◽  
Biochemical Tests ◽  
Trna Synthetases ◽  
Gram Positive Bacteria

ABSTRACT The genomic sequence of Pseudomonas aeruginosa PAO1 was searched for the presence of open reading frames (ORFs) encoding enzymes potentially involved in the formation of Gln-tRNA and of Asn-tRNA. We found ORFs similar to known glutamyl-tRNA synthetases (GluRS), glutaminyl-tRNA synthetases (GlnRS), aspartyl-tRNA synthetases (AspRS), and trimeric tRNA-dependent amidotransferases (AdT) but none similar to known asparaginyl-tRNA synthetases (AsnRS). The absence of AsnRS was confirmed by biochemical tests with crude and fractionated extracts of P. aeruginosa PAO1, with the homologous tRNA as the substrate. The characterization of GluRS, AspRS, and AdT overproduced from their cloned genes in P. aeruginosa and purified to homogeneity revealed that GluRS is discriminating in the sense that it does not glutamylate tRNAGln, that AspRS is nondiscriminating, and that its Asp-tRNAAsn product is transamidated by AdT. On the other hand, tRNAGln is directly glutaminylated by GlnRS. These results show that P. aeruginosa PAO1 is the first organism known to synthesize Asn-tRNA via the indirect pathway and to synthesize Gln-tRNA via the direct pathway. The essential role of AdT in the formation of Asn-tRNA in P. aeruginosa and the absence of a similar activity in the cytoplasm of eukaryotic cells identifies AdT as a potential target for antibiotics to be designed against this human pathogen. Such novel antibiotics could be active against other multidrug-resistant gram-negative pathogens such as Burkholderia and Neisseria as well as all pathogenic gram-positive bacteria.

scholarly journals Isolation and characterization of Pseudomonas aeruginosa bacteriophages — potential agents for phage therapy

2021 ◽  
Author(s):  
MA Kornienko ◽  
NS Kuptsov ◽  
DI Danilov ◽  
RB Gorodnichev ◽  
MV Malakhova ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phage Therapy ◽  
Illumina Miseq ◽  
Multidrug Resistant ◽  
Open Reading Frames ◽  
Lytic Activity ◽  
Isolation And Characterization ◽  
Double Stranded Dna ◽  
Activity Spectrum

Pseudomonas aeruginosa — is one of the pathogens characterized by the critical number of multidrug-resistant (MDR) strains. Phage therapy is considered an alternative to antibiotics, especially in treatment of infections caused by MDR strains. The aim of this study was to isolate and characterize P. aeruginosa phages that could potentially be suitable for treating infectious diseases. To isolate the P. aeruginosa phages, enrichment cultures were used. The lytic activity spectrum was confirmed by spot testing on 40 P. aeruginosa strains. Whole-genome sequencing was performed using Illumina MiSeq instrument. Phylogenetic analysis was done using VICTOR tool. Isolated phages vB_PaeA-55-1w and vB_PaeM-198 from Autographiviridae and Myoviridae families, respectively, had a broad spectrum of lytic activity (about 50% each), including lysis of MDR strains. The genomes vB_PaeA-55-1w and vB_PaeM-198 comprise double-stranded DNA of 42.5 and 66.3 kbp in length, respectively. Open reading frames were annotated for both phages (52 for vB_PaeA-55-1w, and 95 for vB_PaeM-198), no integrases and toxins were detected. On a phylogenetic tree, vB_PaeA-55-1w phage was clustered with phages from the Phikmvvirus genus (Autographiviridae family), which are also used in phage therapy. vB_PaeM-198 phage was clustered with phages from the Pbunavirus genus (Myoviridae family). vB_PaeA-55-1w and vB_PaeM-198 phages could be considered as candidates for phage therapy and may be used to treat infections caused by MDR P. aeruginosa.

scholarly journals Insights into AMS/PCAT transporters from biochemical and structural characterization of a double Glycine motif protease

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Silvia C Bobeica ◽  
Shi-Hui Dong ◽  
Liujie Huo ◽  
Nuria Mazo ◽  
Martin I McLaughlin ◽  
...  
Keyword(s):  
Structural Data ◽  
Leader Peptide ◽  
Gram Negative Bacteria ◽  
Protease Domain ◽  
Peptide Recognition ◽  
Gram Positive Bacteria ◽  
Dual Functional ◽  
Signaling Peptides

The secretion of peptides and proteins is essential for survival and ecological adaptation of bacteria. Dual-functional ATP-binding cassette transporters export antimicrobial or quorum signaling peptides in Gram-positive bacteria. Their substrates contain a leader sequence that is excised by an N-terminal peptidase C39 domain at a double Gly motif. We characterized the protease domain (LahT150) of a transporter from a lanthipeptide biosynthetic operon in Lachnospiraceae and demonstrate that this protease can remove the leader peptide from a diverse set of peptides. The 2.0 Å resolution crystal structure of the protease domain in complex with a covalently bound leader peptide demonstrates the basis for substrate recognition across the entire class of such transporters. The structural data also provide a model for understanding the role of leader peptide recognition in the translocation cycle, and the function of degenerate, non-functional C39-like domains (CLD) in substrate recruitment in toxin exporters in Gram-negative bacteria.

scholarly journals Isolation, Identification And Prevalence Of Pseudomonas Aeruginosa Isolates From Clinical And Environmental Sources In Onitsha Metropolis, Anambra State

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
C. O. Ezeador ◽  
P. C. Ejikeugwu ◽  
S. N. Ushie ◽  
N. R. Agbakoba
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Prevalence Rate ◽  
Nasal Swab ◽  
Blood Agar ◽  
Biochemical Tests ◽  
Anambra State ◽  
Mueller Hinton ◽  
Bluish Green ◽  
Mueller Hinton Agar

This study was aimed to isolate and identify Pseudomonas aeruginosa and to determine the prevalence rate of isolated P. aeruginosa in Hospitals in Onitsha. Isolates of P. aeruginosa were recovered from both clinical and environmental sources using Cetrimide agar, Blood agar, Mueller-Hinton agar and MacConkey agar.  All the inoculated plates were incubated at 37°C for 24-48 hours and growth was evaluated on these media. Isolates were identified on the basis of standard bacteriological methods like morphology, colonial characteristics, smell in culture, haemolysis, as well as pigment production on these media. All suspected isolates were further characterized and identified by many biochemical reactions. Results revealed that only 22 (18.3%) isolates were P. aeruginosa, while other 98 (81.7%) represented other bacterial genera. The 22 isolates included 19 (86.4%) environmental isolates and 3 (13.6%) clinical isolates. Pseudomonas aeruginosa was most commonly isolated from sink (13.6%), then mops and cleaning buckets (9.1%) and least from theatre bed, nasal swab, floor, disinfectant, ear and wound swab (4.5%). The pigment varied from bluish-green to yellowish-green with a grape-like odor. All isolates were Gram negative, produced β-hemolysis on blood agar and were motile. The biochemical tests showed all the isolates to be strongly positive for catalase, oxidase, citrate, and casein hydrolysis. The prevalence rate of P. aeruginosa is relatively high and its isolation from sources like sinks and theatre bed could be suggestive of the role of this pathogen in nosocomial infections.

scholarly journals Characterization of RelA in Acinetobacter baumannii

2020 ◽  
Vol 202 (12) ◽  
Author(s):  
María Pérez-Varela ◽  
Aimee R. P. Tierney ◽  
Ju-Sim Kim ◽  
Andrés Vázquez-Torres ◽  
Philip Rather
Keyword(s):  
Acinetobacter Baumannii ◽  
Galleria Mellonella ◽  
Multidrug Resistant ◽  
Cell Physiology ◽  
Content Type ◽  
Content Model ◽  
Transposon Insertion ◽  
Downstream Effectors

ABSTRACT In response to nutrient depletion, the RelA and SpoT proteins generate the signaling molecule (p)ppGpp, which then controls a number of downstream effectors to modulate cell physiology. In Acinetobacter baumannii strain AB5075, a relA ortholog (ABUW_3302) was identified by a transposon insertion that conferred an unusual colony phenotype. An in-frame deletion in relA (ΔrelA) failed to produce detectable levels of ppGpp when amino acid starvation was induced with serine hydroxamate. The ΔrelA mutant was blocked from switching from the virulent opaque colony variant (VIR-O) to the avirulent translucent colony variant (AV-T), but the rate of AV-T to VIR-O switching was unchanged. In addition, the ΔrelA mutation resulted in a pronounced hypermotile phenotype on 0.35% agar plates. This hypermotility was dependent on the activation of a LysR regulator ABUW_1132, which was required for expression of AbaR, a LuxR family quorum-sensing regulator. In the ΔrelA mutant, ABUW_1132 was also required for the increased expression of an operon composed of the ABUW_3766-ABUW_3773 genes required for production of the surfactant-like lipopeptide acinetin 505. Additional phenotypes identified in the ΔrelA mutant included (i) cell elongation at high density, (ii) reduced formation of persister cells tolerant to colistin and rifampin, and (iii) decreased virulence in a Galleria mellonella model. IMPORTANCE Acinetobacter baumannii is a pathogen of worldwide importance. Due to the increasing prevalence of antibiotic resistance, these infections are becoming increasingly difficult to treat. New therapies are required to combat multidrug-resistant isolates. The role of RelA in A. baumannii is largely unknown. This study demonstrates that like in other bacteria, RelA controls a variety of functions, including virulence. Strategies to inhibit the activity of RelA and the resulting production of ppGpp could inhibit virulence and may represent a new therapeutic approach.

scholarly journals Characterization of biofilm formed by multidrug resistant Pseudomonas aeruginosa DC-17 isolated from dental caries

2020 ◽  
Vol 27 (11) ◽  
pp. 2955-2960
Author(s):  
Xiaojuan Wu ◽  
Dunia A. Al Farraj ◽  
Jayarajapazham Rajaselvam ◽  
Roua M. Alkufeidy ◽  
Ponnuswamy Vijayaraghavan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Dental Caries ◽  
Multidrug Resistant

scholarly journals Characterization of the Urease Operon of Brucella abortus and Assessment of Its Role in Virulence of the Bacterium

2006 ◽  
Vol 75 (2) ◽  
pp. 774-780 ◽  
Author(s):  
Félix J. Sangari ◽  
Asunción Seoane ◽  
María Cruz Rodríguez ◽  
Jesús Agüero ◽  
Juan M. García Lobo
Keyword(s):  
Brucella Abortus ◽  
Urease Activity ◽  
Strong Acid ◽  
Oral Route ◽  
Open Reading Frames ◽  
Human Brucellosis ◽  
Major Route

ABSTRACT Most members of the genus Brucella show strong urease activity. However, the role of this enzyme in the pathogenesis of Brucella infections is poorly understood. We isolated several Tn5 insertion mutants deficient in urease activity from Brucella abortus strain 2308. The mutations of most of these mutants mapped to a 5.7-kbp DNA region essential for urease activity. Sequencing of this region, designated ure1, revealed the presence of seven open reading frames corresponding to the urease structural proteins (UreA, UreB, and UreC) and the accessory proteins (UreD, UreE, UreF, and UreG). In addition to the urease genes, another gene (cobT) was identified, and inactivation of this gene affected urease activity in Brucella. Subsequent analysis of the previously described sequences of the genomes of Brucella spp. revealed the presence of a second urease cluster, ure2, in all them. The ure2 locus was apparently inactive in B. abortus 2308. Urease-deficient mutants were used to evaluate the role of urease in Brucella pathogenesis. The urease-producing strains were found to be resistant in vitro to strong acid conditions in the presence of urea, while urease-negative mutants were susceptible to acid treatment. Similarly, the urease-negative mutants were killed more efficiently than the urease-producing strains during transit through the stomach. These results suggested that urease protects brucellae during their passage through the stomach when the bacteria are acquired by the oral route, which is the major route of infection in human brucellosis.

scholarly journals Characterization of the Enterobacter Phage vB_EclM_CIP9

2020 ◽  
Vol 9 (13) ◽  
Author(s):  
Klara Wang ◽  
Marielou G. Tamayo ◽  
Tiffany V. Penner ◽  
Bradley W. M. Cook ◽  
Deborah A. Court ◽  
...  
Keyword(s):  
Enterobacter Cloacae ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
Open Reading Frames ◽  
Resistant Isolate ◽  
Content Type ◽  
Hospital Acquired Infections ◽  
Hospital Acquired ◽  
Reading Frames

Enterobacter cloacae is an opportunistic pathogen that causes hospital-acquired infections in immunocompromised patients. Here, we describe vB_EclM_CIP9, a novel Enterobacter phage that infects a multidrug-resistant isolate of E. cloacae. Phage vB_EclM_CIP9 is a myovirus that has a 174,924-bp genome, with 296 predicted open reading frames.

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