scholarly journals Lead Drives Complex Dynamics of a Conjugative Plasmid in a Bacterial Community

2021 ◽  
Vol 12 ◽  
Author(s):  
Valentine Cyriaque ◽  
Jonas Stenløkke Madsen ◽  
Laurence Fievez ◽  
Baptiste Leroy ◽  
Lars H. Hansen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Complex Dynamics ◽  
Lead Concentration ◽  
Metal Resistance ◽  
Oxidative Stress Response ◽  
Conjugative Plasmid ◽  
Control Plasmid ◽  
Spread Dynamics ◽  
The Impact

Plasmids carrying metal resistance genes (MRGs) have been suggested to be key ecological players in the adaptation of metal-impacted microbial communities, making them promising drivers of bio-remediation processes. However, the impact of metals on plasmid-mediated spread of MRGs through selection, plasmid loss, and transfer is far from being fully understood. In the present study, we used two-member bacterial communities to test the impact of lead on the dispersal of the IncP plasmid pKJK5 from a Pseudomonas putida KT2440 plasmid donor and two distinct recipients, Variovorax paradoxus B4 or Delftia acidovorans SPH-1 after 4 and 10 days of mating. Two versions of the plasmid were used, carrying or not carrying the lead resistance pbrTRABCD operon, to assess the importance of fitness benefit and conjugative potential for the dispersal of the plasmid. The spread dynamics of metal resistance conveyed by the conjugative plasmid were dependent on the recipient and the lead concentration: For V. paradoxus, the pbr operon did not facilitate neither lead resistance nor variation in plasmid spread. The growth gain brought by the pbr operon to D. acidovorans SPH-1 and P. putida KT2440 at 1 mM Pb enhanced the spread of the plasmid. At 1.5 mM Pb after 4 days, the proteomics results revealed an oxidative stress response and an increased abundance of pKJK5-encoded conjugation and partitioning proteins, which most likely increased the transfer of the control plasmid to D. acidovorans SPH-1 and ensured plasmid maintenance. As a consequence, we observed an increased spread of pKJK5-gfp. Conversely, the pbr operon reduced the oxidative stress response and impeded the rise of conjugation- and partitioning-associated proteins, which slowed down the spread of the pbr carrying plasmid. Ultimately, when a fitness gain was recorded in the recipient strain, the spread of MRG-carrying plasmids was facilitated through positive selection at an intermediate metal concentration, while a high lead concentration induced oxidative stress with positive impacts on proteins encoding plasmid conjugation and partitioning.

scholarly journals Oxidative Stress Response Tips the Balance in Aspergillus terreus Amphotericin B Resistance

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Emina Jukic ◽  
Michael Blatzer ◽  
Wilfried Posch ◽  
Marion Steger ◽  
Ulrike Binder ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Amphotericin B ◽  
Aspergillus Terreus ◽  
Expression Profiles ◽  
Oxidative Stress Response ◽  
Mrna Levels ◽  
Sod Activity ◽  
Content Type ◽  
The Impact

ABSTRACT In this study, we characterize the impact of antioxidative enzymes in amphotericin B (AmB)-resistant (ATR) and rare AmB-susceptible (ATS) clinical Aspergillus terreus isolates. We elucidate expression profiles of superoxide dismutase (SOD)- and catalase (CAT)-encoding genes, enzymatic activities of SODs, and superoxide anion production and signaling pathways involved in the oxidative stress response (OSR) in ATS and ATR strains under AmB treatment conditions. We show that ATR strains possess almost doubled basal SOD activity compared to that of ATS strains and that ATR strains exhibit an enhanced OSR, with significantly higher sod2 mRNA levels and significantly increased cat transcripts in ATR strains upon AmB treatment. In particular, inhibition of SOD and CAT proteins renders resistant isolates considerably susceptible to the drug in vitro. In conclusion, this study shows that SODs and CATs are crucial for AmB resistance in A. terreus and that targeting the OSR might offer new treatment perspectives for resistant species.

Effect of lactic-co-glycolicacid nanoparticles polymer encapsulated quercetin on hypoxia/reoxygenation-induced cardiomyocyte injury and its mechanism

2021 ◽  
Vol 11 (10) ◽  
pp. 1653-1659
Author(s):  
Shubo Song ◽  
Weijie Liang ◽  
Bin Li ◽  
Haoju Dong ◽  
Kaiyuan Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Glycolic Acid ◽  
Plga Nanoparticles ◽  
Oxidative Stress Response ◽  
The Impact ◽  
Hypoxia Reoxygenation

This study aimed to elucidate the impact of quercetin (Que)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-Que) on hypoxia/reoxygenation (H/R)-induced cardiomyocyte (CM) injury and its mechanism. PLGA-Que was first prepared, and H/R CMs were intervened with either PLGA-Que or free Que. The results showed that both PLGA-Que and free Que could enhance H/R CM viability, inhibit apoptosis, and lower the oxidative stress response. However, PLGA-Que was more protective of H/R CMs than free Que. Subsequently, noticeably enhanced viability and reduced apoptosis of H/R CMs were determined after miR-499-5p or miR-375 up-regulation. Lastly, the inhibitor sequences of either miR-499-5p or miR-375 were transfected into PLGAQue-treated H/R CMs. The results showed that both sequences reversed the enhancement of viability and inhibition of apoptosis of H/R CMs intervened by PLGA-Que. Thus, PLGA-Que can treat H/R-induced CM injury by up-regulating miR-499-5p and miR-375.

scholarly journals The Onset of Tacrolimus Biosynthesis in Streptomyces tsukubaensis Is Dependent on the Intracellular Redox Status

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 703
Author(s):  
Sílvia D. S. Pires ◽  
Rute Oliveira ◽  
Pedro Moradas-Ferreira ◽  
Marta V. Mendes
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Metabolic Flux ◽  
Redox Status ◽  
Oxidative Stress Response ◽  
Molecular Response ◽  
Streptomyces Tsukubaensis ◽  
The Impact ◽  
Intracellular Redox Status ◽  
Intracellular Redox

The oxidative stress response is a key mechanism that microorganisms have to adapt to changeling environmental conditions. Adaptation is achieved by a fine-tuned molecular response that extends its influence to primary and secondary metabolism. In the past, the role of the intracellular redox status in the biosynthesis of tacrolimus in Streptomyces tsukubaensis has been briefly acknowledged. Here, we investigate the impact of the oxidative stress response on tacrolimus biosynthesis in S. tsukubaensis. Physiological characterization of S. tsukubaensis showed that the onset of tacrolimus biosynthesis coincided with the induction of catalase activity. In addition, tacrolimus displays antioxidant properties and thus a controlled redox environment would be beneficial for its biosynthesis. In addition, S. tsukubaensis ∆ahpC strain, a strain defective in the H2O2-scavenging enzyme AhpC, showed increased production of tacrolimus. Proteomic and transcriptomic studies revealed that the tacrolimus over-production phenotype was correlated with a metabolic rewiring leading to increased availability of tacrolimus biosynthetic precursors. Altogether, our results suggest that the carbon source, mainly used for cell growth, can trigger the production of tacrolimus by modulating the oxidative metabolism to favour a low oxidizing intracellular environment and redirecting the metabolic flux towards the increase availability of biosynthetic precursors.

scholarly journals Environmental Conditions Modulate the Transcriptomic Response of Both Caulobacter crescentus Morphotypes to Cu Stress

2021 ◽  
Vol 9 (6) ◽  
pp. 1116
Author(s):  
Laurens Maertens ◽  
Pauline Cherry ◽  
Françoise Tilquin ◽  
Rob Van Houdt ◽  
Jean-Yves Matroule
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Stress Responses ◽  
Caulobacter Crescentus ◽  
Oxidative Stress Response ◽  
Transport Systems ◽  
Transcriptomic Response ◽  
Swarmer Cell ◽  
Cu Stress ◽  
Cellular Environment

Bacteria encounter elevated copper (Cu) concentrations in multiple environments, varying from mining wastes to antimicrobial applications of copper. As the role of the environment in the bacterial response to Cu ion exposure remains elusive, we used a tagRNA-seq approach to elucidate the disparate responses of two morphotypes of Caulobacter crescentus NA1000 to moderate Cu stress in a complex rich (PYE) medium and a defined poor (M2G) medium. The transcriptome was more responsive in M2G, where we observed an extensive oxidative stress response and reconfiguration of the proteome, as well as the induction of metal resistance clusters. In PYE, little evidence was found for an oxidative stress response, but several transport systems were differentially expressed, and an increased need for histidine was apparent. These results show that the Cu stress response is strongly dependent on the cellular environment. In addition, induction of the extracytoplasmic function sigma factor SigF and its regulon was shared by the Cu stress responses in both media, and its central role was confirmed by the phenotypic screening of a sigF::Tn5 mutant. In both media, stalked cells were more responsive to Cu stress than swarmer cells, and a stronger basal expression of several cell protection systems was noted, indicating that the swarmer cell is inherently more Cu resistant. Our approach also allowed for detecting several new transcription start sites, putatively indicating small regulatory RNAs, and additional levels of Cu-responsive regulation.

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