scholarly journals Isolation and Characterization of an Autoinducer Synthase from Acinetobacter baumannii

2008 ◽  
Vol 190 (9) ◽  
pp. 3386-3392 ◽  
Author(s):  
Chen Niu ◽  
Katy M. Clemmer ◽  
Robert A. Bonomo ◽  
Philip N. Rather
Keyword(s):  
Acinetobacter Baumannii ◽  
Homoserine Lactone ◽  
Transcriptional Level ◽  
Human Pathogen ◽  
Isolation And Characterization ◽  
Opportunistic Human Pathogen ◽  
Biofilm Development ◽  
Culture Supernatants ◽  
Ethyl Acetate Extracts

ABSTRACT The opportunistic human pathogen Acinetobacter baumannii strain M2 was found to produce distinct acyl-homoserine lactone (AHL) signals based on the use of an Agrobacterium tumefaciens traG-lacZ biosensor. An A. baumannii gene, designated abaI, was cloned and directed AHL production in recombinant Escherichia coli. The AbaI protein was similar to members of the LuxI family of autoinducer synthases and was predicted to be the only autoinducer synthase encoded by A. baumannii. The primary AHL signal directed by AbaI was identified by mass spectrometry as being N-(3-hydroxydodecanoyl)-l-HSL (3-hydroxy-C12-HSL). Minor amounts of at least five additional AHLs were also identified. The expression of abaI at the transcriptional level was activated by ethyl acetate extracts of culture supernatants or by synthetic 3-hydroxy-C12-HSL. An abaI::Km mutant failed to produce any detectable AHL signals and was impaired in biofilm development.

scholarly journals Isolation and characterization of the SPT2 gene, a negative regulator of Ty-controlled yeast gene expression.

1985 ◽  
Vol 5 (7) ◽  
pp. 1543-1553 ◽  
Author(s):  
G S Roeder ◽  
C Beard ◽  
M Smith ◽  
S Keranen
Keyword(s):  
Gene Product ◽  
Regulatory Region ◽  
Negative Regulator ◽  
Transcriptional Level ◽  
Wild Type ◽  
Isolation And Characterization ◽  
Mutant Strains ◽  
Insertion Mutations ◽  
His4 Gene

The his4-917 mutation of Saccharomyces cerevisiae results from the insertion of the Ty element Ty917 into the regulatory region of the HIS4 gene and renders the cell His-. The hist4-912 delta mutant, which carries a solo delta in the 5'-noncoding region of HIS4, is His+ at 37 degrees C but His- at 23 degrees C. Both these mutations interfere with HIS4 expression at the transcriptional level. The His- phenotype of both insertion mutations is suppressed by mutations at the SPT2 locus. The product of the wild-type SPT2 gene apparently represses HIS4 transcription in these mutant strains; this repression is relieved when the SPT2 gene is destroyed by mutation. The repression of transcription by SPT2 presumably results from an interaction between the SPT2+ gene product and Ty or delta sequences. In this paper, we report the cloning and DNA sequence analysis of the wild-type SPT2 gene and show that the gene is capable of encoding a protein of 333 amino acids in length. In addition, we show that a dominant mutation of the SPT2 gene results from the generation of an ochre codon which is presumed to lead to a shortened SPT2 gene product.

scholarly journals Isolation and Characterization of Acinetobacter baumannii Recovered from Campylobacter Selective Medium

2016 ◽  
Vol 7 ◽  
Author(s):  
Dinesh M. Fernando ◽  
Izhar U. H. Khan ◽  
Rakesh Patidar ◽  
David R. Lapen ◽  
Guylaine Talbot ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Selective Medium ◽  
Isolation And Characterization

Isolation and characterization of ϕAB2: a novel bacteriophage of Acinetobacter baumannii

2010 ◽  
Vol 161 (4) ◽  
pp. 308-314 ◽  
Author(s):  
Nien-Tsung Lin ◽  
Pei-Yu Chiou ◽  
Kai-Chih Chang ◽  
Li-Kuang Chen ◽  
Meng-Jiun Lai
Keyword(s):  
Acinetobacter Baumannii ◽  
Isolation And Characterization

scholarly journals AbaM Regulates Quorum Sensing, Biofilm Formation and Virulence in Acinetobacter baumannii

2021 ◽  
Author(s):  
Mario López-Martín ◽  
Jean-Frédéric Dubern ◽  
Morgan R. Alexander ◽  
Paul Williams
Keyword(s):  
Quorum Sensing ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Plant Pathogens ◽  
Galleria Mellonella ◽  
Homoserine Lactone ◽  
Infection Model ◽  
Wild Type ◽  
Surface Motility ◽  
Biofilm Development

Acinetobacter baumannii possesses a single divergent luxR/luxI-type quorum sensing (QS) locus named abaR/abaI. This locus also contains a third gene located between abaR and abaI which we term abaM that codes for an uncharacterized member of the RsaM protein family known to regulate N-acylhomoserine lactone (AHL) dependent QS in other β- and γ-proteobacteria. Here we show that disruption of abaM via a T26 insertion in A. baumannii strain AB5075 resulted in increased production of N-(3-hydroxydodecanoyl)-L-homoserine lactone (OHC12) and enhanced surface motility and biofilm formation. In contrast to the wild type and abaI::T26 mutant, the virulence of the abaM::T26 mutant was completely attenuated in a Galleria mellonella infection model. Transcriptomic analysis of the abaM::T26 mutant revealed that AbaM differentially regulates at least 76 genes including the csu pilus operon and the acinetin 505 lipopeptide biosynthetic operon, that are involved in surface adherence, biofilm formation and virulence. A comparison of the wild type, abaM::T26 and abaI::T26 transcriptomes, indicates that AbaM regulates ∼21% of the QS regulon including the csu operon. Moreover, the QS genes (abaI/abaR) were among the most upregulated in the abaM::T26 mutant. A. baumannii lux-based abaM reporter gene fusions revealed that abaM expression is positively regulated by QS but negatively auto-regulated. Overall, the data presented in this work demonstrates that AbaM plays a central role in regulating A. baumannii QS, virulence, surface motility and biofilm formation. Importance Acinetobacter baumanni is a multi-antibiotic resistant pathogen of global healthcare importance. Understanding Acinetobacter virulence gene regulation could aid the development of novel anti-infective strategies. In A. baumannii, the abaR and abaI genes that code for the receptor and synthase components of an N-acylhomoserine (AHL) lactone-dependent quorum sensing system (QS) are separated by abaM. Here we show that although mutation of abaM increased AHL production, surface motility and biofilm development, it resulted in the attenuation of virulence. AbaM was found to control both QS-dependent and QS-independent genes. The significance of this work lies in the identification of AbaM, an RsaM ortholog known to control virulence in plant pathogens, as a modulator of virulence in a human pathogen.

scholarly journals Complete Genome Sequence of the Nosocomial Pathogen Acinetobacter nosocomialis Strain M2

2019 ◽  
Vol 8 (44) ◽  
Author(s):  
Bailey Pehde ◽  
Nicholas Lizer ◽  
Michael Carruthers
Keyword(s):  
Acinetobacter Baumannii ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Acinetobacter Calcoaceticus ◽  
Human Pathogen ◽  
Nosocomial Pathogen ◽  
Content Type ◽  
Opportunistic Human Pathogen

Acinetobacter nosocomialis is an opportunistic human pathogen that is part of the Acinetobacter calcoaceticus/Acinetobacter baumannii (ACB) complex. Here, we report the complete genome sequence of Acinetobacter nosocomialis strain M2.

scholarly journals CsrA Coordinates Compatible Solute Synthesis in Acinetobacter baumannii and Facilitates Growth in Human Urine

2021 ◽  
Author(s):  
Josephine Joy Hubloher ◽  
Kim Schabacker ◽  
Volker Müller ◽  
Beate Averhoff
Keyword(s):  
Acinetobacter Baumannii ◽  
Multidrug Resistant ◽  
Compatible Solute ◽  
Human Pathogen ◽  
Content Type ◽  
Clinical Environments ◽  
Resistant Strains ◽  
Opportunistic Human Pathogen ◽  
Mrna Binding ◽  
Optimal Adaptation

The opportunistic human pathogen Acinetobacter baumannii has become one of the leading causes of nosocomial infections around the world due to the increasing prevalence of multidrug-resistant strains and their optimal adaptation to clinical environments and the human host. Recently, it was found that CsrA, a global mRNA binding posttranscriptional regulator, plays a role in osmotic stress adaptation, virulence, and growth on amino acids of A. baumannii AB09-003 and 17961.

scholarly journals Complete Genome Sequence of Klebsiella pneumoniae Myophage Mineola

2019 ◽  
Vol 8 (17) ◽  
Author(s):  
Justin X. Boeckman ◽  
Lauren Lessor ◽  
Jason J. Gill ◽  
Mei Liu
Keyword(s):  
Drug Resistance ◽  
Klebsiella Pneumoniae ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Human Pathogen ◽  
Content Type ◽  
Isolation And Characterization ◽  
Wide Range

Klebsiella pneumoniae is an important human pathogen due to the wide range of infections it can cause and its emerging drug resistance. Isolation and characterization of phage infecting K. pneumoniae could be important for future therapeutic applications.

scholarly journals The Opportunistic Human Pathogen Acinetobacter baumannii Senses and Responds to Light

2010 ◽  
Vol 192 (24) ◽  
pp. 6336-6345 ◽  
Author(s):  
María A. Mussi ◽  
Jennifer A. Gaddy ◽  
Matías Cabruja ◽  
Brock A. Arivett ◽  
Alejandro M. Viale ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Physiological Responses ◽  
Opportunistic Pathogen ◽  
Bacterial Cells ◽  
Human Pathogen ◽  
Bacterial Physiology ◽  
Phototrophic Microorganisms ◽  
Sense And Respond ◽  
Opportunistic Human Pathogen ◽  
Output Domain

ABSTRACT Light is a ubiquitous environmental signal that many organisms sense and respond to by modulating their physiological responses accordingly. While this is an expected response among phototrophic microorganisms, the ability of chemotrophic prokaryotes to sense and react to light has become a puzzling and novel issue in bacterial physiology, particularly among bacterial pathogens. In this work, we show that the opportunistic pathogen Acinetobacter baumannii senses and responds to blue light. Motility and formation of biofilms and pellicles were observed only when bacterial cells were incubated in darkness. In contrast, the killing of Candida albicans filaments was enhanced when they were cocultured with bacteria under light. These bacterial responses depend on the expression of the A. baumannii ATCC 17978 A1S_2225 gene, which codes for an 18.6-kDa protein that contains an N-terminal blue-light-sensing-using flavin (BLUF) domain and lacks a detectable output domain(s). Spectral analyses of the purified recombinant protein showed its ability to sense light by a red shift upon illumination. Therefore, the A1S_2225 gene, which is present in several members of the Acinetobacter genus, was named blue-light-sensing A (blsA). Interestingly, temperature plays a role in the ability of A. baumannii to sense and respond to light via the BlsA photoreceptor protein.

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