scholarly journals Identification and Characterization of Quorum-Quenching Activity of N-Acylhomoserine Lactonase from Coagulase-Negative Staphylococci

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 483
Author(s):  
Tomohiro Morohoshi ◽  
Yaoki Kamimura ◽  
Nobutaka Someya
Keyword(s):  
Quorum Sensing ◽  
Opportunistic Pathogen ◽  
Quorum Quenching ◽  
Coagulase Negative Staphylococci ◽  
Sensing Systems ◽  
Genes Encoding ◽  
Acyl Chains ◽  
Gene Homologue ◽  
Identification And Characterization

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signals in Gram-negative bacteria. Many genes encoding AHL-degrading enzymes have been cloned and characterized in various microorganisms. Coagulase-negative staphylococci (CNS) are present on the skin of animals and are considered low-virulent species. The AHL-lactonase gene homologue, ahlS, was present in the genomes of the CNS strains Staphylococcus carnosus, Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus sciuri. We cloned the candidate ahlS homologue from six CNS strains into the pBBR1MCS5 vector. AhlS from the CNS strains showed a higher degrading activity against AHLs with short acyl chains compared to those with long acyl chains. AhlS from S. sciuri was expressed and purified as a maltose-binding protein (MBP) fusion. Pseudomonas aeruginosa is an opportunistic pathogen that regulates several virulence factors such as elastase and pyocyanin by quorum-sensing systems. When MBP-AhlS was added to the culture of P. aeruginosa PAO1, pyocyanin production and elastase activity were substantially reduced compared to those in untreated PAO1. These results demonstrate that the AHL-degrading activity of AhlS from the CNS strains can inhibit quorum sensing in P. aeruginosa PAO1.

scholarly journals Characterization of Quorum Sensing and Quorum Quenching Soil Bacteria Isolated from Malaysian Tropical Montane Forest

Sensors ◽  
2012 ◽  
Vol 12 (4) ◽  
pp. 4846-4859 ◽  
Author(s):  
Teik-Min Chong ◽  
Chong-Lek Koh ◽  
Choon-Kook Sam ◽  
Yeun-Mun Choo ◽  
Wai-Fong Yin ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Soil Bacteria ◽  
Quorum Quenching ◽  
Montane Forest ◽  
Tropical Montane Forest

scholarly journals Identification and Characterization of Novel Fusion Genes with Potential Clinical Applications in Mexican Children with Acute Lymphoblastic Leukemia

2019 ◽  
Vol 20 (10) ◽  
pp. 2394 ◽  
Author(s):  
Minerva Mata-Rocha ◽  
Angelica Rangel-López ◽  
Elva Jiménez-Hernández ◽  
Blanca Angélica Morales-Castillo ◽  
Carolina González-Torres ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Fusion Gene ◽  
Lymphoblastic Leukemia ◽  
Fusion Genes ◽  
Cancer Etiology ◽  
Mexican Children ◽  
Genes Encoding ◽  
Identification And Characterization ◽  
Current Risk

Acute lymphoblastic leukemia is the most common type of childhood cancer worldwide. Mexico City has one of the highest incidences and mortality rates of this cancer. It has previously been recognized that chromosomal translocations are important in cancer etiology. Specific fusion genes have been considered as important treatment targets in childhood acute lymphoblastic leukemia (ALL). The present research aimed at the identification and characterization of novel fusion genes with potential clinical implications in Mexican children with acute lymphoblastic leukemia. The RNA-sequencing approach was used. Four fusion genes not previously reported were identified: CREBBP-SRGAP2B, DNAH14-IKZF1, ETV6-SNUPN, ETV6-NUFIP1. Although a fusion gene is not sufficient to cause leukemia, it could be involved in the pathogenesis of the disease. Notably, these new translocations were found in genes encoding for hematopoietic transcription factors which are known to play an important role in leukemogenesis and disease prognosis such as IKZF1, CREBBP, and ETV6. In addition, they may have an impact on the prognosis of Mexican pediatric patients with ALL, with the potential to be included in the current risk stratification schemes or used as therapeutic targets.

Identification and characterization of a LuxI/R-type quorum sensing system in Pseudoalteromonas

2019 ◽  
Vol 170 (6-7) ◽  
pp. 243-255 ◽  
Author(s):  
Zhiliang Yu ◽  
Dongliang Yu ◽  
Yanfeng Mao ◽  
Mengting Zhang ◽  
Mengdan Ding ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Identification And Characterization

scholarly journals Postgenomic Scan of Metallo-β-Lactamase Homologues in Rhizobacteria: Identification and Characterization of BJP-1, a Subclass B3 Ortholog from Bradyrhizobium japonicum

2006 ◽  
Vol 50 (6) ◽  
pp. 1973-1981 ◽  
Author(s):  
Magdalena Stoczko ◽  
Jean-Marie Frère ◽  
Gian Maria Rossolini ◽  
Jean-Denis Docquier
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Catalytic Efficiency ◽  
Open Reading Frames ◽  
Human Pathogens ◽  
Microbial Genomes ◽  
E Coli ◽  
Genes Encoding ◽  
And Function ◽  
Identification And Characterization

ABSTRACT The diffusion of metallo-β-lactamases (MBLs) among clinically important human pathogens represents a therapeutic issue of increasing importance. However, the origin of these resistance determinants is largely unknown, although an important number of proteins belonging to the MBL superfamily have been identified in microbial genomes. In this work, we analyzed the distribution and function of genes encoding MBL-like proteins in the class Rhizobiales. Among 12 released complete genomes of members of the class Rhizobiales, a total of 57 open reading frames (ORFs) were found to have the MBL conserved motif and identity scores with MBLs ranging from 8 to 40%. On the basis of the best identity scores with known MBLs, four ORFs were cloned into Escherichia coli for heterologous expression. Among their products, one (blr6230) encoded by the Bradyrhizobium japonicum USDA110 genome, named BJP-1, hydrolyzed β-lactams when expressed in E. coli. BJP-1 enzyme is most closely related to the CAU-1 enzyme from Caulobacter vibrioides (40% amino acid sequence identity), a member of subclass B3 MBLs. A kinetic analysis revealed that BJP-1 efficiently hydrolyzed most β-lactam substrates, except aztreonam, ticarcillin, and temocillin, with the highest catalytic efficiency measured with meropenem. Compared to other MBLs, BJP-1 was less sensitive to inactivation by chelating agents.

scholarly journals Regulation of Quorum Sensing by RpoS inPseudomonas aeruginosa

2000 ◽  
Vol 182 (15) ◽  
pp. 4356-4360 ◽  
Author(s):  
Marvin Whiteley ◽  
Matthew R. Parsek ◽  
E. P. Greenberg
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Gene Transcription ◽  
Opportunistic Pathogen ◽  
Null Mutant ◽  
Global Regulators ◽  
Acylhomoserine Lactone ◽  
Sensing Systems

ABSTRACT The LasR-LasI and RhlR-RhlI quorum-sensing systems are global regulators of gene expression in the opportunistic pathogenPseudomonas aeruginosa. Previous studies suggest that the RhlR-RhlI system activates expression of rpoS. We constructed merodiploid strains of P. aeruginosa containing the native rpoS gene and an rpoS-lacZ fusion. Studies of lacZ transcription in these strains indicated that rpoS was not regulated by RhlR-RhlI. We also generated an rpoS null mutant. This rpoS mutant showed elevated levels of rhlI (but not rhlR) transcription, elevated levels of the RhlI-generated acylhomoserine lactone quorum-sensing signal, and elevated levels of RhlR-RhlI-regulated gene transcription. These findings indicate that there is a relationship between RpoS and quorum sensing, but rather than the RhlR-RhlI system influencing the expression ofrpoS, it appears that RpoS regulates rhlI.

scholarly journals Function of the bacteriophytochrome BphP in the RpoS/Las quorum-sensing network of Pseudomonas aeruginosa

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1651-1664 ◽  
Author(s):  
Katalin Barkovits ◽  
Britta Schubert ◽  
Sabrina Heine ◽  
Maurice Scheer ◽  
Nicole Frankenberg-Dinkel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Response Regulator ◽  
Red Light ◽  
Regulatory System ◽  
Global Gene Expression ◽  
Opportunistic Pathogen ◽  
Pleiotropic Effect ◽  
Genes Encoding

The bacterial phytochrome of Pseudomonas aeruginosa (PaBphP) is an in vitro-active red/far-red light sensor histidine kinase of a two-component regulatory system. Despite solid biochemical data, its function in this heterotrophic, opportunistic pathogen is still unknown. Previous studies established that the genes encoding the two necessary phytochrome components BphO, a chromophore-producing haem oxygenase, and BphP, the apo-phytochrome, are co-transcribed in a bicistronic operon. Transcription has been shown to be induced in the stationary phase and to be dependent on the alternative sigma factor RpoS. Here we show an additional regulation of bphP expression through the quorum-sensing (QS) regulator LasR. This regulation is also reflected in a combination of expression profile experiments and proteome analyses of wild-type and phytochrome-deficient strains. While PaBphP has a pleiotropic effect on global gene expression, 66 % of the downregulated genes in the phytochrome mutant display a link to the Las QS system. Most of these genes seem to be indirectly regulated by LasR through BphP and the unknown response regulator BphR. A model of phytochrome function within the Las QS network is presented.

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