Global transcriptional analysis of stress-response strategies in Acidithiobacillus ferrooxidans ATCC 23270 exposed to organic extractant—Lix984n

ABSTRACTThe genome ofAzospirillum brasilenseencodes five RpoH sigma factors: two OxyR transcription regulators and three catalases. The aim of this study was to understand the role they play during oxidative stress and their regulatory interconnection. Out of the 5 paralogs of RpoH present inA. brasilense, inactivation of onlyrpoH1rendersA. brasilenseheat sensitive. While transcript levels ofrpoH1were elevated by heat stress, those ofrpoH3andrpoH5were upregulated by H2O2. Catalase activity was upregulated inA. brasilenseand itsrpoH::kmmutants in response to H2O2except in the case of therpoH5::kmmutant, suggesting a role for RpoH5 in regulating inducible catalase. Transcriptional analysis of thekatN,katAI, andkatAII genes revealed that the expression ofkatNandkatAII was severely compromised in therpoH3::kmandrpoH5::kmmutants, respectively. Regulation ofkatNandkatAII by RpoH3 and RpoH5, respectively, was further confirmed in anEscherichia colitwo-plasmid system. Regulation ofkatAII by OxyR2 was evident by a drastic reduction in growth, KatAII activity, andkatAII::lacZexpression in anoxyR2::kmmutant. This study reports the involvement of RpoH3 and RpoH5 sigma factors in regulating oxidative stress response in alphaproteobacteria. We also report the regulation of an inducible catalase by a cascade of alternative sigma factors and an OxyR. Out of the three catalases inA. brasilense, those corresponding tokatNandkatAII are regulated by RpoH3 and RpoH5, respectively. The expression ofkatAII is regulated by a cascade of RpoE1→RpoH5 and OxyR2.IMPORTANCEIn silicoanalysis of theA. brasilensegenome showed the presence of multiple paralogs of genes involved in oxidative stress response, which included 2 OxyR transcription regulators and 3 catalases. So far,Deinococcus radioduransandVibrio choleraeare known to harbor two paralogs of OxyR, andSinorhizobium melilotiharbors three catalases. We do not yet know how the expression of multiple catalases is regulated in any bacterium. Here we show the role of multiple RpoH sigma factors and OxyR in regulating the expression of multiple catalases inA. brasilenseSp7. Our work gives a glimpse of systems biology ofA. brasilenseused for responding to oxidative stress.

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Primed to be strong, primed to be fast: modeling benefits of microbial stress responses

FEMS Microbiology Ecology ◽

10.1093/femsec/fiz114 ◽

2019 ◽

Vol 95 (8) ◽

Author(s):

Felix Wesener ◽

Britta Tietjen

Keyword(s):

Stress Response ◽

Stress Responses ◽

Defense Mechanisms ◽

Defense Mechanism ◽

Equation Model ◽

Response Strategies ◽

Early Stress ◽

The Impact ◽

Microbial Stress ◽

Population Performance

ABSTRACT Organisms are prone to different stressors and have evolved various defense mechanisms. One such defense mechanism is priming, where a mild preceding stress prepares the organism toward an improved stress response. This improved response can strongly vary, and primed organisms have been found to respond with one of three response strategies: a shorter delay to stress, a faster buildup of their response or a more intense response. However, a universal comparative assessment, which response is superior under a given environmental setting, is missing. We investigate the benefits of the three improved responses for microorganisms with an ordinary differential equation model, simulating the impact of an external stress on a microbial population that is either naïve or primed. We systematically assess the resulting population performance for different costs associated with priming and stress conditions. Our results show that independent of stress type and priming costs, the stronger primed response is most beneficial for longer stress phases, while the faster and earlier responses increase population performance and survival probability under short stresses. Competition increases priming benefits and promotes the early stress response. This dependence on the ecological context highlights the importance of including primed response strategies into microbial stress ecology.

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Genome-wide comparison of phage M13-infected vs. uninfectedEscherichia coli

Canadian Journal of Microbiology ◽

10.1139/w04-113 ◽

2005 ◽

Vol 51 (1) ◽

pp. 29-35 ◽

Cited By ~ 14

Author(s):

Fredrik Karlsson ◽

Ann-Christin Malmborg-Hager ◽

Ann-Sofie Albrekt ◽

Carl A.K Borrebaeck

Keyword(s):

Escherichia Coli ◽

Stress Response ◽

Acid Stress ◽

Phage Infection ◽

Transcriptional Analysis ◽

Filamentous Phage ◽

Phosphotransferase System ◽

E Coli ◽

Genome Wide

To identify Escherichia coli genes potentially regulated by filamentous phage infection, we used oligonucleotide microarrays. Genome-wide comparison of phage M13-infected and uninfected E. coli, 2 and 20 min after infection, was performed. The analysis revealed altered transcription levels of 12 E. coli genes in response to phage infection, and the observed regulation of phage genes correlated with the known in vivo pattern of M13 mRNA species. Ten of the 12 host genes affected could be grouped into 3 different categories based on cellular function, suggesting a coordinated response. The significantly upregulated genes encode proteins involved in reactions of the energy-generating phosphotransferase system and transcription processing, which could be related to phage transcription. No genes belonging to any known E. coli stress response pathways were scored as upregulated. Furthermore, phage infection led to significant downregulation of transcripts of the bacterial genes gadA, gadB, hdeA, gadE, slp, and crl. These downregulated genes are normally part of the host stress response mechanisms that protect the bacterium during conditions of acid stress and stationary phase transition. The phage-infected cells demonstrated impaired function of the oxidative and the glutamate-dependent acid resistance systems. Thus, global transcriptional analysis and functional analysis revealed previously unknown host responses to filamentous phage infection.Key words: filamentous phage infection, global transcriptional analysis, AR, Escherichia coli.

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Comparative Transcriptional Analysis of Clinically Relevant Heat Stress Response in Clostridium difficile Strain 630

PLoS ONE ◽

10.1371/journal.pone.0042410 ◽

2012 ◽

Vol 7 (7) ◽

pp. e42410 ◽

Cited By ~ 22

Author(s):

Nigel G. Ternan ◽

Shailesh Jain ◽

Malay Srivastava ◽

Geoff McMullan

Keyword(s):

Heat Stress ◽

Stress Response ◽

Clostridium Difficile ◽

Transcriptional Analysis ◽

Heat Stress Response

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Global Regulatory Impact of ClpP Protease of Staphylococcus aureus on Regulons Involved in Virulence, Oxidative Stress Response, Autolysis, and DNA Repair

Journal of Bacteriology ◽

10.1128/jb.00074-06 ◽

2006 ◽

Vol 188 (16) ◽

pp. 5783-5796 ◽

Cited By ~ 128

Author(s):

Antje Michel ◽

Franziska Agerer ◽

Christof R. Hauck ◽

Mathias Herrmann ◽

Joachim Ullrich ◽

...

Keyword(s):

Oxidative Stress ◽

Staphylococcus Aureus ◽

Dna Repair ◽

Stress Response ◽

Oxidative Stress Response ◽

Transcriptional Analysis ◽

Expression Of Genes ◽

Wide Range ◽

Genes Encoding ◽

Regulatory Impact

ABSTRACT Staphylococcus aureus is an important pathogen, causing a wide range of infections including sepsis, wound infections, pneumonia, and catheter-related infections. In several pathogens ClpP proteases were identified by in vivo expression technologies to be important for virulence. Clp proteolytic complexes are responsible for adaptation to multiple stresses by degrading accumulated and misfolded proteins. In this report clpP, encoding the proteolytic subunit of the ATP-dependent Clp protease, was deleted, and gene expression of ΔclpP was determined by global transcriptional analysis using DNA-microarray technology. The transcriptional profile reveals a strong regulatory impact of ClpP on the expression of genes encoding proteins that are involved in the pathogenicity of S. aureus and adaptation of the pathogen to several stresses. Expression of the agr system and agr-dependent extracellular virulence factors was diminished. Moreover, the loss of clpP leads to a complete transcriptional derepression of genes of the CtsR- and HrcA-controlled heat shock regulon and a partial derepression of genes involved in oxidative stress response, metal homeostasis, and SOS DNA repair controlled by PerR, Fur, MntR, and LexA. The levels of transcription of genes encoding proteins involved in adaptation to anaerobic conditions potentially regulated by an Fnr-like regulator were decreased. Furthermore, the expression of genes whose products are involved in autolysis was deregulated, leading to enhanced autolysis in the mutant. Our results indicate a strong impact of ClpP proteolytic activity on virulence, stress response, and physiology in S. aureus.

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Global Transcriptional Analysis of Yeast Cell Death Induced by Mutation of Sister Chromatid Cohesin

Comparative and Functional Genomics ◽

10.1155/2008/634283 ◽

2008 ◽

Vol 2008 ◽

pp. 1-16 ◽

Cited By ~ 2

Author(s):

Qun Ren ◽

Hui Yang ◽

Bifeng Gao ◽

Zhaojie Zhang

Keyword(s):

Cell Death ◽

Stress Response ◽

Internal Stress ◽

Sister Chromatid ◽

Apoptotic Cell ◽

Chromatin Condensation ◽

External Stress ◽

Apoptotic Cell Death ◽

Transcriptional Analysis ◽

External Stimuli

Cohesin is a protein complex that regulates sister chromatid cohesin during cell division. Malfunction in chromatid cohesin results in chromosome missegregation and aneuploidy. Here, we report that mutations of MCD1 and PDS5, two major components of cohesin in budding yeast, cause apoptotic cell death, which is characterized by externalization of phosphatidylserine at cytoplasmic membrane, chromatin condensation and fragmentation, and ROS production. Microarray analysis suggests that the cell death caused by mutation of MCD1 or PDS5 is due to the internal stress response, contrasting to the environmental or external stress response induced by external stimuli, such as hydrogen peroxide. A common feature shared by the internal stress response and external stress response is the response to stimulus, including response to DNA damage, mitochondria functions, and oxidative stress, which play an important role in yeast apoptotic cell death.

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Investigating Nurses Stress Response Strategies During the COVID-19 Pandemic

Materia Socio Medica ◽

10.5455/msm.2021.33.168-173 ◽

2021 ◽

Vol 33 (3) ◽

pp. 168

Author(s):

Stiliani Kotrotsiou ◽

Dimitrios Theofanidis ◽

Maria Malliarou ◽

Zoe Konstanti ◽

Pavlos Sarafis ◽

...

Keyword(s):

Stress Response ◽

Response Strategies

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Heat-Stress Responses Differ among Species from Different ‘Bangia’ Clades of Bangiales (Rhodophyta)

Plants ◽

10.3390/plants10081733 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1733

Author(s):

Ho Viet Khoa ◽

Puja Kumari ◽

Hiroko Uchida ◽

Akio Murakami ◽

Satoshi Shimada ◽

...

Keyword(s):

Heat Stress ◽

Stress Response ◽

Stress Responses ◽

Red Alga ◽

Heat Sensitivity ◽

Heat Stress Response ◽

Stress Memory ◽

Response Strategies ◽

Heat Stress Tolerance ◽

Bangia Atropurpurea

The red alga ‘Bangia’ sp. ESS1, a ‘Bangia’ 2 clade member, responds to heat stress via accelerated asexual reproduction and acquires thermotolerance based on heat-stress memory. However, whether these strategies are specific to ‘Bangia’ 2, especially ‘Bangia’ sp. ESS1, or whether they are employed by all ‘Bangia’ species is currently unknown. Here, we examined the heat-stress responses of ‘Bangia’ sp. ESS2, a newly identified ‘Bangia’ clade 3 member, and Bangia atropurpurea. Intrinsic thermotolerance differed among species: Whereas ‘Bangia’ sp. ESS1 survived at 30 °C for 7 days, ‘Bangia’ sp. ESS2 and B. atropurpurea did not, with B. atropurpurea showing the highest heat sensitivity. Under sublethal heat stress, the release of asexual spores was highly repressed in ‘Bangia’ sp. ESS2 and completely repressed in B. atropurpurea, whereas it was enhanced in ‘Bangia’ sp. ESS1. ‘Bangia’ sp. ESS2 failed to acquire heat-stress tolerance under sublethal heat-stress conditions, whereas the acquisition of heat tolerance by priming with sublethal high temperatures was observed in both B. atropurpurea and ‘Bangia’ sp. ESS1. Finally, unlike ‘Bangia’ sp. ESS1, neither ‘Bangia’ sp. ESS2 nor B. atropurpurea acquired heat-stress memory. These findings provide insights into the diverse heat-stress response strategies among species from different clades of ‘Bangia’.

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Human IgM Inhibits the Formation of Titan-Like Cells in Cryptococcus neoformans

Infection and Immunity ◽

10.1128/iai.00046-20 ◽

2020 ◽

Vol 88 (4) ◽

Cited By ~ 2

Author(s):

Nuria Trevijano-Contador ◽

Kaila M. Pianalto ◽

Connie B. Nichols ◽

Oscar Zaragoza ◽

J. Andrew Alspaugh ◽

...

Keyword(s):

Cell Wall ◽

Stress Response ◽

B Cell ◽

Cryptococcus Neoformans ◽

Cell Formation ◽

Transcriptional Analysis ◽

Content Type ◽

Human Immunoglobulins ◽

Genes Encoding

ABSTRACT Human studies have shown associations between cryptococcal meningitis and reduced IgM memory B cell levels, and studies in IgM- and/or B cell-deficient mice have demonstrated increased Cryptococcus neoformans dissemination from lungs to brain. Since immunoglobulins are part of the immune milieu that C. neoformans confronts in a human host, and its ability to form titan cells is an important virulence mechanism, we determined the effect of human immunoglobulins on C. neoformans titan cell formation in vitro. (i) Fluorescence microscopy showed normal human IgG and IgM bind C. neoformans. (ii) C. neoformans grown in titan cell-inducing medium with IgM, not IgG, inhibited titan-like cell formation. (iii) Absorption of IgM with laminarin or curdlan (branched and linear 1-3-beta-d-glucans, respectively) decreased this effect. (iv) Transmission electron microscopy revealed that cells grown with IgM had small capsules and unique features not seen with cells grown with IgG. (v) Comparative transcriptional analysis of cell wall, capsule, and stress response genes showed that C. neoformans grown with IgM, not IgG or phosphate-buffered saline (PBS), had decreased expression of chitin synthetase, CHS1, CHS2, and CHS8, and genes encoding cell wall carbohydrate synthetases α-1-3-glucan (AGS1) and β-1,3-glucan (FKS1). IgM also decreased expression of RIM101 and HOG1, genes encoding central regulators of C. neoformans stress response pathways and cell morphogenesis. Our data show human IgM affects C. neoformans morphology in vitro and suggest that the hypothesis that human immunoglobulins may affect C. neoformans virulence in vivo warrants further investigation.

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