scholarly journals «PemIK (PemK/PemI) type II TA system from Klebsiella pneumoniae clinical strains inhibits lytic phage»

2021 ◽  
Author(s):  
Ines Bleriot ◽  
Lucia Blasco ◽  
Olga Pacios ◽  
Laura Fernández-García ◽  
Antón Ambroa ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Metabolic Activity ◽  
Reference Strain ◽  
Phage Infection ◽  
Clinical Strain ◽  
Lytic Phage ◽  
Type Ii ◽  
Clinical Strains ◽  
Qrt Pcr

Abstract Since their discovery, toxin-antitoxin systems have captivated many scientists. Recent studies demonstrated that a key role of TA systems is phage inhibition. Therefore, the aim of this study was to investigate the role of the PemIK (PemK/PemI) type II TA system in phage inhibition by its intrinsic expression in clinical strains of Klebsiella pneumoniae carrying OXA-48 carbapenemase and by induced its expression in an IPTG-inducible plasmid in a reference strain of K. pneumoniae ATCC®10031™. qRT-PCR revealed that pemK toxin in clinical strain ST16-OXA48 was induced when phage did not infect the strain, whereas when phage infection was successful pemK toxin was not induced. In addition, induced expression of the whole system did not inhibit phage infection, whereas overexpression of the pemK toxin prevented infection during the first hours. To investigate the molecular mechanism involved in the PemK toxin-mediated inhibition of phage infection, an assay measuring metabolic activity was performed, which revealed that production of toxin PemK led to the dormancy of the bacteria. Thus, we demonstrate that the PemK/PemI TA system plays a role in phage infection, and that the action of the free toxin causes the cells to go into a dormant state resulting in inhibition of phage infections.

scholarly journals Mechanisms of Tolerance and Resistance to Chlorhexidine in Clinical Strains of Klebsiella pneumoniae Producers of Carbapenemase: Role of New Type II Toxin-Antitoxin System, PemIK

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 566
Author(s):  
Ines Bleriot ◽  
Lucia Blasco ◽  
Mercedes Delgado-Valverde ◽  
Ana Gual-de-Torrella ◽  
Anton Ambroa ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Molecular Mechanisms ◽  
Cross Resistance ◽  
Type Ii ◽  
Clinical Strains ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
New Type ◽  
High Level

Although the failure of antibiotic treatment is normally attributed to resistance, tolerance and persistence display a significant role in the lack of response to antibiotics. Due to the fact that several nosocomial pathogens show a high level of tolerance and/or resistance to chlorhexidine, in this study we analyzed the molecular mechanisms associated with chlorhexidine adaptation in two clinical strains of Klebsiella pneumoniae by phenotypic and transcriptomic studies. These two strains belong to ST258-KPC3 (high-risk clone carrying β-lactamase KPC3) and ST846-OXA48 (low-risk clone carrying β-lactamase OXA48). Our results showed that the K. pneumoniae ST258-KPC3CA and ST846-OXA48CA strains exhibited a different behavior under chlorhexidine (CHLX) pressure, adapting to this biocide through resistance and tolerance mechanisms, respectively. Furthermore, the appearance of cross-resistance to colistin was observed in the ST846-OXA48CA strain (tolerant to CHLX), using the broth microdilution method. Interestingly, this ST846-OXA48CA isolate contained a plasmid that encodes a novel type II toxin/antitoxin (TA) system, PemI/PemK. We characterized this PemI/PemK TA system by cloning both genes into the IPTG-inducible pCA24N plasmid, and found their role in persistence and biofilm formation. Accordingly, the ST846-OXA48CA strain showed a persistence biphasic curve in the presence of a chlorhexidine-imipenem combination, and these results were confirmed by the enzymatic assay (WST-1).

scholarly journals Role of the MexEF-OprN Efflux System in Low-Level Resistance of Pseudomonas aeruginosa to Ciprofloxacin

2011 ◽  
Vol 55 (12) ◽  
pp. 5676-5684 ◽  
Author(s):  
Catherine Llanes ◽  
Thilo Köhler ◽  
Isabelle Patry ◽  
Barbara Dehecq ◽  
Christian van Delden ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Reference Strain ◽  
Efflux Pump ◽  
Resistance Mechanisms ◽  
Efflux System ◽  
Content Type ◽  
Clinical Strains ◽  
Major Mechanism ◽  
Level Resistance

ABSTRACTIn this study, we investigated the resistance mechanisms to fluoroquinolones of 85 non-cystic fibrosis strains ofPseudomonas aeruginosaexhibiting a reduced susceptibility to ciprofloxacin (MICs from 0.25 to 2 μg/ml). In addition to MexAB-OprM (31 of 85 isolates) and MexXY/OprM (39 of 85), the MexEF-OprN efflux pump (10 of 85) was found to be commonly upregulated in this population that is considered susceptible or of intermediate susceptibility to ciprofloxacin, according to current breakpoints. Analysis of the 10 MexEF-OprN overproducers (nfxCmutants) revealed the presence of various mutations in themexT(2 isolates),mexS(5 isolates), and/ormvaT(2 isolates) genes, the inactivation of which is known to increase the expression of themexEF-oprNoperon in reference strain PAO1-UW. However, these genes were intact in 3 of 10 of the clinical strains. Interestingly, ciprofloxacin at 2 μg/ml or 4 μg/ml preferentially selectednfxCmutants from wild-type clinical strains (n= 10 isolates) and from first-step mutants (n= 10) overexpressing Mex pumps, thus indicating that MexEF-OprN represents a major mechanism by whichP. aeruginosamay acquire higher resistance levels to fluoroquinolones. These data support the notion that thenfxCmutants may be more prevalent in the clinical setting than anticipated and strongly suggest the involvement of still unknown genes in the regulation of this efflux system.

scholarly journals The Type II Secretory System Mediates Phage Infection in Vibrio cholera

2021 ◽  
Vol 11 ◽  
Author(s):  
Huihui Sun ◽  
Ming Liu ◽  
Fenxia Fan ◽  
Zhe Li ◽  
Yufeng Fan ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Specific Binding ◽  
Phage Infection ◽  
Lytic Phage ◽  
Tail Fiber ◽  
Type Ii ◽  
Dna Injection ◽  
Bacteriophage Infection ◽  
Inner Membrane Protein ◽  
Secretory System

Attachment and specific binding to the receptor on the host cell surface is the first step in the process of bacteriophage infection. The lytic phage VP2 is used in phage subtyping of the Vibrio cholerae biotype El Tor of the O1 serogroup; however, its infection mechanism is poorly understood. In this study, we aimed to identify its receptor on V. cholerae. The outer membrane protein EpsD in the type II secretory system (T2SS) was found to be related to VP2-specific adsorption to V. cholerae, and the T2SS inner membrane protein EpsM had a role in successful VP2 infection, although it was not related to adsorption of VP2. The tail fiber protein gp20 of VP2 directly interacts with EpsD. Therefore, we found that in V. cholerae, in addition to the roles of the T2SS as the transport apparatus of cholera toxin secretion and filamentous phage release, the T2SS is also used as the receptor for phage infection and probably as the channel for phage DNA injection. Our study expands the understanding of the roles of the T2SS in bacteria.

scholarly journals A Complex Relationship between Visfatin and Resistin and microRNA: An In Vitro Study on Human Chondrocyte Cultures

2018 ◽  
Vol 19 (12) ◽  
pp. 3909 ◽  
Author(s):  
Sara Cheleschi ◽  
Nicola Giordano ◽  
Nila Volpi ◽  
Sara Tenti ◽  
Ines Gallo ◽  
...  
Keyword(s):  
Collagen Type ◽  
In Vitro Study ◽  
Complex Relationship ◽  
Type Ii ◽  
Qrt Pcr ◽  
Chondrocyte Cultures ◽  
Oa Chondrocytes ◽  
Induced Apoptosis

Growing evidence indicates the important role of adipokines and microRNA (miRNA) in osteoarthritis (OA) pathogenesis. The purpose of the present study was to investigate the effect of visfatin and resistin on some miRNA (34a, 140, 146a, 155, 181a, let-7e), metalloproteinases (MMPs), and collagen type II alpha 1 chain (Col2a1) in human OA chondrocytes and in the T/C-28a2 cell line. The implication of nuclear factor (NF)-κB in response to adipokines was also assessed. Chondrocytes were stimulated with visfatin (5 or 10 μg/mL) and resistin (50 or 100 ng/mL) with or without NF-κB inhibitor (BAY-11-7082, 1 μM) for 24 h. Viability and apoptosis were detected by MMT and cytometry, miRNA, MMP-1, MMP-13, and Col2a1 by qRT-PCR and NF-κB activation by immunofluorescence. Visfatin and resistin significantly reduced viability, induced apoptosis, increased miR-34a, miR-155, miR-181a, and miR-let7e, and reduced miR-140 and miR-146a gene expression in OA chondrocytes. MMP-1, MMP-13, and Col2a1 were significantly modulated by treatment of OA chondrocytes with adipokines. Visfatin and resistin significantly increased NF-κB activation, while the co-treatment with BAY11-7082 did not change MMPs or Col2a1 levels beyond that caused by single treatment. Visfatin and resistin regulate the expression levels of some miRNA involved in OA pathogenesis and exert catabolic functions in chondrocytes via the NF-κB pathway. These data confirm the complex relationship between adipokines and miRNA.

Role of hyperglucagonemia in maintenance of increased rates of hepatic glucose output in type II diabetics

Diabetes ◽  
1987 ◽  
Vol 36 (3) ◽  
pp. 274-283 ◽  
Author(s):  
A. D. Baron ◽  
L. Schaeffer ◽  
P. Shragg ◽  
O. G. Kolterman
Keyword(s):  
Type Ii ◽  
Hepatic Glucose Output ◽  
Hepatic Glucose ◽  
Type Ii Diabetics ◽  
Glucose Output

Role of lipid oxidation in pathogenesis of insulin resistance of obesity and type II diabetes

Diabetes ◽  
1987 ◽  
Vol 36 (11) ◽  
pp. 1341-1350 ◽  
Author(s):  
J. P. Felber ◽  
E. Ferrannini ◽  
A. Golay ◽  
H. U. Meyer ◽  
D. Theibaud ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Lipid Oxidation ◽  
Type Ii Diabetes ◽  
Type Ii

Corticosteroid Catabolism by Klebsiella pneumoniae as a Possible Mechanism for Increased Pneumonia Risk

2019 ◽  
Vol 20 (4) ◽  
pp. 309-316 ◽  
Author(s):  
Pritam Chattopadhyay ◽  
Goutam Banerjee
Keyword(s):  
Amino Acid ◽  
Klebsiella Pneumoniae ◽  
Kegg Pathway ◽  
Degradation Pathway ◽  
Amino Acid Sequences ◽  
Biological Mechanism ◽  
Clinical Strains ◽  
Catabolism Pathway ◽  
Steroid Catabolism ◽  
Nutrition Source

Background: Several strains of Klebsiella pneumoniae are responsible for causing pneumonia in lung and thereby causing death in immune-suppressed patients. In recent year, few investigations have reported the enhancement of K. pneumoniae population in patients using corticosteroid containing inhaler. Objectives: The biological mechanism(s) behind this increased incidence has not been elucidated. Therefore, the objective of this investigating was to explore the relation between Klebsiella pneumoniae and increment in carbapenamase producing Enterobacteriaceae score (ICS). Methods: The available genomes of K. pneumoniae and the amino acid sequences of steroid catabolism pathway enzymes were taken from NCBI database and KEGG pathway tagged with UniPort database, respectively. We have used different BLAST algorithms (tBLASTn, BLASTp, psiBLAST, and delBLAST) to identify enzymes (by their amino acid sequence) involved in steroid catabolism. Results: A total of 13 enzymes (taken from different bacterial candidates) responsible for corticosteroid degradation have been identified in the genome of K. pneumoniae. Finally, 8 enzymes (K. pneumoniae specific) were detected in four clinical strains of K. pneumoniae. This investigation intimates that this ability to catabolize corticosteroids could potentially be one mechanism behind the increased pneumonia incidence. Conclusion: The presence of corticosteroid catabolism enzymes in K. pneumoniae enhances the ability to utilize corticosteroid for their own nutrition source. This is the first report to demonstrate the corticosteroid degradation pathway in clinical strains of K. pneumoniae.

Overexpression of Pygo2 Increases Differentiation of Human Umbilical Cord Mesenchymal Stem Cells into Cardiomyocyte-like Cells

2020 ◽  
Vol 20 (4) ◽  
pp. 318-324 ◽  
Author(s):  
Lei Yang ◽  
Shuoji Zhu ◽  
Yongqing Li ◽  
Jian Zhuang ◽  
Jimei Chen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Umbilical Cord ◽  
Heart Function ◽  
Critical Role ◽  
Human Umbilical Cord ◽  
Stem Cell Markers ◽  
Quantitative Real Time Pcr ◽  
Qrt Pcr

Background: Our previous studies have shown that Pygo (Pygopus) in Drosophila plays a critical role in adult heart function that is likely conserved in mammals. However, its role in the differentiation of human umbilical cord mesenchymal stem cells (hUC-MSCs) into cardiomyocytes remains unknown. Objective: To investigate the role of pygo2 in the differentiation of hUC-MSCs into cardiomyocytes. Methods: Third passage hUC-MSCs were divided into two groups: a p+ group infected with the GV492-pygo2 virus and a p− group infected with the GV492 virus. After infection and 3 or 21 days of incubation, Quantitative real-time PCR (qRT-PCR) was performed to detect pluripotency markers, including OCT-4 and SOX2. Nkx2.5, Gata-4 and cTnT were detected by immunofluorescence at 7, 14 and 21 days post-infection, respectively. Expression of cardiac-related genes—including Nkx2.5, Gata-4, TNNT2, MEF2c, ISL-1, FOXH1, KDR, αMHC and α-Actin—were analyzed by qRT-PCR following transfection with the virus at one, two and three weeks. Results : After three days of incubation, there were no significant changes in the expression of the pluripotency stem cell markers OCT-4 and SOX2 in the p+ group hUC-MSCs relative to controls (OCT-4: 1.03 ± 0.096 VS 1, P > 0.05, SOX2: 1.071 ± 0.189 VS 1, P > 0.05); however, after 21 days, significant decreases were observed (OCT-4: 0.164 ± 0.098 VS 1, P < 0.01, SOX2: 0.209 ± 0.109 VS 1, P < 0.001). Seven days following incubation, expression of mesoderm specialisation markers, such as Nkx2.5, Gata-4, MEF2c and KDR, were increased; at 14 days following incubation, expression of cardiac genes, such as Nkx2.5, Gata-4, TNNT2, MEF2c, ISL-1, FOXH1, KDR, αMHC and α-Actin, were significantly upregulated in the p+ group relative to the p− group (P < 0.05). Taken together, these findings suggest that overexpression of pygo2 results in more hUCMSCs gradually differentiating into cardiomyocyte-like cells. Conclusion: We are the first to show that overexpression of pygo2 significantly enhances the expression of cardiac-genic genes, including Nkx2.5 and Gata-4, and promotes the differentiation of hUC-MSCs into cardiomyocyte-like cells.

scholarly journals Sub-Inhibitory Concentrations of Ciprofloxacin Alone and Combinations with Plant-Derived Compounds against P. aeruginosa Biofilms and Their Effects on the Metabolomic Profile of P. aeruginosa Biofilms

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 414
Author(s):  
Didem Kart ◽  
Tuba Reçber ◽  
Emirhan Nemutlu ◽  
Meral Sagiroglu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Inhibitory Concentration ◽  
Molecular Level ◽  
Metabolomic Profile ◽  
Gene Expressions ◽  
New Agents ◽  
Qrt Pcr ◽  
Metabolomic Approach

Introduction: Alternative anti-biofilm agents are needed to combat Pseudomonas aeruginosa infections. The mechanisms behind these new agents also need to be revealed at a molecular level. Materials and methods: The anti-biofilm effects of 10 plant-derived compounds on P. aeruginosa biofilms were investigated using minimum biofilm eradication concentration (MBEC) and virulence assays. The effects of ciprofloxacin and compound combinations on P. aeruginosa in mono and triple biofilms were compared. A metabolomic approach and qRT-PCR were applied to the biofilms treated with ciprofloxacin in combination with baicalein, esculin hydrate, curcumin, and cinnamaldehyde at sub-minimal biofilm inhibitory concentration (MBIC) concentrations to highlight the specific metabolic shifts between the biofilms and to determine the quorum sensing gene expressions, respectively. Results: The combinations of ciprofloxacin with curcumin, baicalein, esculetin, and cinnamaldehyde showed more reduced MBICs than ciprofloxacin alone. The quorum sensing genes were downregulated in the presence of curcumin and cinnamaldehyde, while upregulated in the presence of baicalein and esculin hydrate rather than for ciprofloxacin alone. The combinations exhibited different killing effects on P. aeruginosa in mono and triple biofilms without affecting its virulence. The findings of the decreased metabolite levels related to pyrimidine and lipopolysaccharide synthesis and to down-regulated alginate and lasI expressions strongly indicate the role of multifactorial mechanisms for curcumin-mediated P. aeruginosa growth inhibition. Conclusions: The use of curcumin, baicalein, esculetin, and cinnamaldehyde with ciprofloxacin will help fight against P. aeruginosa biofilms. To the best of our knowledge, this is the first study of its kind to define the effect of plant-based compounds as possible anti-biofilm agents with low MBICs for the treatment of P. aeruginosa biofilms through metabolomic pathways.

scholarly journals Identification and characterization of early Fusarium wilt responsive mRNAs and long non-coding RNAs in banana root using high-throughput sequencing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chunzhen Cheng ◽  
Fan Liu ◽  
Na Tian ◽  
Raphael Anue Mensah ◽  
Xueli Sun ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Acid Metabolism ◽  
Function Analysis ◽  
Regulatory Role ◽  
Novel Genes ◽  
Root Transcriptome ◽  
Qrt Pcr ◽  
Non Coding Rnas ◽  
Infection Stage

AbstractFusarium wilt disease, caused by Fusarium oxysporum f.sp. cubense (Foc), has been recognized as the most devastating disease to banana. The regulatory role of long non-coding RNAs (lncRNAs) in plant defense has been verified in many plant species. However, the understanding of their role during early FocTR4 (Foc tropical race 4) infection stage is very limited. In this study, lncRNA sequencing was used to reveal banana root transcriptome profile changes during early FocTR4 infection stages. Quantitative real time PCR (qRT-PCR) was performed to confirm the expression of eight differentially expressed (DE) lncRNAs (DELs) and their predicted target genes (DETs), and three DE genes (DEGs). Totally, 12,109 lncRNAs, 36,519 mRNAs and 2642 novel genes were obtained, of which 1398 (including 78 DELs, 1220 DE known genes and 100 DE novel genes) were identified as FocTR4 responsive DE transcripts. Gene function analysis revealed that most DEGs were involved in biosynthesis of secondary metabolites, plant–pathogen interaction, plant hormone signal transduction, phenylalanine metabolism, phenylpropanoid biosynthesis, alpha-linolenic acid metabolism and so on. Coincidently, many DETs have been identified as DEGs in previous transcriptome studies. Moreover, many DETs were found to be involved in ribosome, oxidative phosphorylation, lipoic acid metabolism, ubiquitin mediated proteolysis, N-glycan biosynthesis, protein processing in endoplasmic reticulum and DNA damage response pathways. QRT-PCR result showed the expression patterns of the selected transcripts were mostly consistent with our lncRNA sequencing data. Our present study showed the regulatory role of lncRNAs on known biotic and abiotic stress responsive genes and some new-found FocTR4 responsive genes, which can provide new insights into FocTR4-induced changes in the banana root transcriptome during the early pathogen infection stage.

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