scholarly journals Towards robust Pseudomonas cell factories to harbour novel biosynthetic pathways

2021 ◽  
Author(s):  
Nora Lisa Bitzenhofer ◽  
Luzie Kruse ◽  
Stephan Thies ◽  
Benedikt Wynands ◽  
Thorsten Lechtenberg ◽  
...  
Keyword(s):  
Stress Response ◽  
Cell Envelope ◽  
Molecular Genetic ◽  
Membrane Integrity ◽  
Natural Compounds ◽  
Enzyme Engineering ◽  
Fine Tuning ◽  
Biotechnological Production ◽  
Cell Factories ◽  
Reactive Aldehydes

Abstract Biotechnological production in bacteria enables access to numerous valuable chemical compounds. Nowadays, advanced molecular genetic toolsets, enzyme engineering as well as the combinatorial use of biocatalysts, pathways, and circuits even bring new-to-nature compounds within reach. However, the associated substrates and biosynthetic products often cause severe chemical stress to the bacterial hosts. Species of the Pseudomonas clade thus represent especially valuable chassis as they are endowed with multiple stress response mechanisms, which allow them to cope with a variety of harmful chemicals. A built-in cell envelope stress response enables fast adaptations that sustain membrane integrity under adverse conditions. Further, effective export machineries can prevent intracellular accumulation of diverse harmful compounds. Finally, toxic chemicals such as reactive aldehydes can be eliminated by oxidation and stress-induced damage can be recovered. Exploiting and engineering these features will be essential to support an effective production of natural compounds and new chemicals. In this article, we therefore discuss major resistance strategies of Pseudomonads along with approaches pursued for their targeted exploitation and engineering in a biotechnological context. We further highlight strategies for the identification of yet unknown tolerance-associated genes and their utilisation for engineering next-generation chassis and finally discuss effective measures for pathway fine-tuning to establish stable cell factories for the effective production of natural compounds and novel biochemicals.

scholarly journals Regulation of Flagellum Biosynthesis in Response to Cell Envelope Stress inSalmonella entericaSerovar Typhimurium

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Imke Spöring ◽  
Sebastian Felgner ◽  
Matthias Preuße ◽  
Denitsa Eckweiler ◽  
Manfred Rohde ◽  
...  
Keyword(s):  
Immune System ◽  
Stress Response ◽  
Pathogenic Bacteria ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Flagellar Biosynthesis ◽  
Envelope Stress ◽  
Flagellum Biosynthesis ◽  
Hostile Environments ◽  
Prime Target

ABSTRACTFlagellum-driven motility ofSalmonella entericaserovar Typhimurium facilitates host colonization. However, the large extracellular flagellum is also a prime target for the immune system. As consequence, expression of flagella is bistable within a population ofSalmonella, resulting in flagellated and nonflagellated subpopulations. This allows the bacteria to maximize fitness in hostile environments. The degenerate EAL domain protein RflP (formerly YdiV) is responsible for the bistable expression of flagella by directing the flagellar master regulatory complex FlhD4C2with respect to proteolytic degradation. Information concerning the environmental cues controlling expression ofrflPand thus about the bistable flagellar biosynthesis remains ambiguous. Here, we demonstrated that RflP responds to cell envelope stress and alterations of outer membrane integrity. Lipopolysaccharide (LPS) truncation mutants ofSalmonellaTyphimurium exhibited increasing motility defects due to downregulation of flagellar gene expression. Transposon mutagenesis and genetic profiling revealed that σ24(RpoE) and Rcs phosphorelay-dependent cell envelope stress response systems sense modifications of the lipopolysaccaride, low pH, and activity of the complement system. This subsequently results in activation of RflP expression and degradation of FlhD4C2via ClpXP. We speculate that the presence of diverse hostile environments inside the host might result in cell envelope damage and would thus trigger the repression of resource-costly and immunogenic flagellum biosynthesis via activation of the cell envelope stress response.IMPORTANCEPathogenic bacteria such asSalmonellaTyphimurium sense and adapt to a multitude of changing and stressful environments during host infection. At the initial stage of gastrointestinal colonization,Salmonellauses flagellum-mediated motility to reach preferred sites of infection. However, the flagellum also constitutes a prime target for the host’s immune response. Accordingly, the pathogen needs to determine the spatiotemporal stage of infection and control flagellar biosynthesis in a robust manner. We found thatSalmonellauses signals from cell envelope stress-sensing systems to turn off production of flagella. We speculate that downregulation of flagellum synthesis after cell envelope damage in hostile environments aids survival ofSalmonelladuring late stages of infection and provides a means to escape recognition by the immune system.

scholarly journals The LiaFSR System Regulates the Cell Envelope Stress Response in Streptococcus mutans

2009 ◽  
Vol 191 (9) ◽  
pp. 2973-2984 ◽  
Author(s):  
Prashanth Suntharalingam ◽  
M. D. Senadheera ◽  
Richard W. Mair ◽  
Céline M. Lévesque ◽  
Dennis G. Cvitkovitch
Keyword(s):  
Stress Response ◽  
Streptococcus Mutans ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Transcriptional Analysis ◽  
Dependent Manner ◽  
Bacterial Survival ◽  
Concentration Dependent Manner ◽  
Lipid Ii ◽  
Envelope Stress

ABSTRACT Maintaining cell envelope integrity is critical for bacterial survival, including bacteria living in a complex and dynamic environment such as the human oral cavity. Streptococcus mutans, a major etiological agent of dental caries, uses two-component signal transduction systems (TCSTSs) to monitor and respond to various environmental stimuli. Previous studies have shown that the LiaSR TCSTS in S. mutans regulates virulence traits such as acid tolerance and biofilm formation. Although not examined in streptococci, homologs of LiaSR are widely disseminated in Firmicutes and function as part of the cell envelope stress response network. We describe here liaSR and its upstream liaF gene in the cell envelope stress tolerance of S. mutans strain UA159. Transcriptional analysis established liaSR as part of the pentacistronic liaFSR-ppiB-pnpB operon. A survey of cell envelope antimicrobials revealed that mutants deficient in one or all of the liaFSR genes were susceptible to Lipid II cycle interfering antibiotics and to chemicals that perturbed the cell membrane integrity. These compounds induced liaR transcription in a concentration-dependent manner. Notably, under bacitracin stress conditions, the LiaFSR signaling system was shown to induce transcription of several genes involved in membrane protein synthesis, peptidoglycan biosynthesis, envelope chaperone/proteases, and transcriptional regulators. In the absence of an inducer such as bacitracin, LiaF repressed LiaR-regulated expression, whereas supplementing cultures with bacitracin resulted in derepression of liaSR. While LiaF appears to be an integral component of the LiaSR signaling cascade, taken collectively, we report a novel role for LiaFSR in sensing cell envelope stress and preserving envelope integrity in S. mutans.

scholarly journals Direct Interaction of Polar Scaffolding Protein Wag31 with Nucleoid-Associated Protein Rv3852 Regulates Its Polar Localization

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1558
Author(s):  
Rajni Garg ◽  
Chinmay Anand ◽  
Sohini Ganguly ◽  
Sandhya Rao ◽  
Rinkee Verma ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Envelope ◽  
Transmembrane Helix ◽  
Ectopic Expression ◽  
Direct Interaction ◽  
Fine Tuning ◽  
Scaffolding Protein ◽  
Physical Interaction ◽  
Cell Wall Synthesis ◽  
Interaction Approach

Rv3852 is a unique nucleoid-associated protein (NAP) found exclusively in Mycobacterium tuberculosis (Mtb) and closely related species. Although annotated as H-NS, we showed previously that it is very different from H-NS in its properties and is distinct from other NAPs, anchoring to cell membrane by virtue of possessing a C-terminal transmembrane helix. Here, we investigated the role of Rv3852 in Mtb in organizing architecture or synthesis machinery of cell wall by protein–protein interaction approach. We demonstrated a direct physical interaction of Rv3852 with Wag31, an important cell shape and cell wall integrity determinant essential in Mtb. Wag31 localizes to the cell poles and possibly acts as a scaffold for cell wall synthesis proteins, resulting in polar cell growth in Mtb. Ectopic expression of Rv3852 in M. smegmatis resulted in its interaction with Wag31 orthologue DivIVAMsm. Binding of the NAP to Wag31 appears to be necessary for fine-tuning Wag31 localization to the cell poles, enabling complex cell wall synthesis in Mtb. In Rv3852 knockout background, Wag31 is mislocalized resulting in disturbed nascent peptidoglycan synthesis, suggesting that the NAP acts as a driver for localization of Wag31 to the cell poles. While this novel association between these two proteins presents one of the mechanisms to structure the elaborate multi-layered cell envelope of Mtb, it also exemplifies a new function for a NAP in mycobacteria.

Fine-tuning of microsolvation and hydrogen bond interaction regulates substrate channelling in the course of flavonoid biosynthesis

2016 ◽  
Vol 18 (15) ◽  
pp. 10337-10345 ◽  
Author(s):  
Julien Diharce ◽  
Jérôme Golebiowski ◽  
Sébastien Fiorucci ◽  
Serge Antonczak
Keyword(s):  
Hydrogen Bond ◽  
Natural Compounds ◽  
Flavonoid Biosynthesis ◽  
Fine Tuning ◽  
Efficient Production ◽  
Substrate Channeling ◽  
Metabolite Formation ◽  
Hydrogen Bond Interaction ◽  
Bond Interaction ◽  
Substrate Channelling

In the course of metabolite formation, some multienzymatic edifices, the so-called metabolon, are formed and lead through substrate channeling to a more efficient production of the natural compounds.

A single exposure to a sublethal pediocin concentration initiates a resistance-associated temporal cell envelope and general stress response inListeria monocytogenes

2014 ◽  
Vol 17 (4) ◽  
pp. 1134-1151 ◽  
Author(s):  
Martin F. Laursen ◽  
Martin I. Bahl ◽  
Tine R. Licht ◽  
Lone Gram ◽  
Gitte M. Knudsen
Keyword(s):  
Stress Response ◽  
Cell Envelope ◽  
Single Exposure ◽  
General Stress Response ◽  
General Stress

scholarly journals MicroRNAs Are Involved in Regulating Plant Development and Stress Response through Fine-Tuning of TIR1/AFB-Dependent Auxin Signaling

2022 ◽  
Vol 23 (1) ◽  
pp. 510
Author(s):  
Pan Luo ◽  
Dongwei Di ◽  
Lei Wu ◽  
Jiangwei Yang ◽  
Yufang Lu ◽  
...  
Keyword(s):  
Stress Response ◽  
Fine Tuning ◽  
Auxin Signaling ◽  
In Planta ◽  
Auxin Response ◽  
Signal Molecule ◽  
Master Regulators ◽  
Non Coding Rna ◽  
Complex Regulation ◽  
Indole 3 Acetic Acid

Auxin, primarily indole-3-acetic acid (IAA), is a versatile signal molecule that regulates many aspects of plant growth, development, and stress response. Recently, microRNAs (miRNAs), a type of short non-coding RNA, have emerged as master regulators of the auxin response pathways by affecting auxin homeostasis and perception in plants. The combination of these miRNAs and the autoregulation of the auxin signaling pathways, as well as the interaction with other hormones, creates a regulatory network that controls the level of auxin perception and signal transduction to maintain signaling homeostasis. In this review, we will detail the miRNAs involved in auxin signaling to illustrate its in planta complex regulation.

scholarly journals Phyletic distribution and diversification of the Phage Shock Protein stress response system in bacteria and archaea

2021 ◽  
Author(s):  
Philipp F. Popp ◽  
Vadim M. Gumerov ◽  
Ekaterina P. Andrianova ◽  
Lisa Bewersdorf ◽  
Thorsten Mascher ◽  
...  
Keyword(s):  
Stress Response ◽  
Large Scale ◽  
Cell Envelope ◽  
Model Organisms ◽  
Microbial World ◽  
Natural Classification ◽  
Response System ◽  
Core Proteins ◽  
Envelope Stress

AbstractThe bacterial cell envelope is an essential structure that protects the cell from environmental threats, while simultaneously serving as communication interface and diffusion barrier. Therefore, maintaining cell envelope integrity is of vital importance for all microorganisms. Not surprisingly, evolution has shaped conserved protection networks that connect stress perception, transmembrane signal transduction and mediation of cellular responses upon cell envelope stress. The phage shock protein (PSP) stress response is one of such conserved protection networks. Most of the knowledge about the Psp response comes from studies in the Gram-negative model bacterium, Escherichia coli where the Psp system consists of several well-defined protein components. Homologous systems were identified in representatives of Proteobacteria, Actinobacteria, and Firmicutes; however, the Psp system distribution in the microbial world remains largely unknown. By carrying out a large-scale, unbiased comparative genomics analysis, we found components of the Psp system in many bacterial and archaeal phyla and demonstrated that the PSP system deviates dramatically from the proteobacterial prototype. Two of its core proteins, PspA and PspC, have been integrated in various (often phylum-specifically) conserved protein networks during evolution. Based on protein sequence and gene neighborhood analyses of pspA and pspC homologs, we built a natural classification system of PSP networks in bacteria and archaea. We performed a comprehensive in vivo protein interaction screen for the PSP network newly identified in the Gram-positive model organism Bacillus subtilis and found a strong interconnected PSP response system, illustrating the validity of our approach. Our study highlights the diversity of PSP organization and function across many bacterial and archaeal phyla and will serve as foundation for future studies of this envelope stress response beyond model organisms.

scholarly journals Genetic analysis of the role of the conserved inner membrane protein CvpA in EHEC resistance to deoxycholate

2020 ◽  
Author(s):  
Alyson R. Warr ◽  
Rachel T. Giorgio ◽  
Matthew K. Waldor
Keyword(s):  
Stress Response ◽  
Membrane Protein ◽  
Bile Salt ◽  
Cell Envelope ◽  
Enteric Bacteria ◽  
Enteric Pathogens ◽  
Inner Membrane ◽  
Bacterial Phyla ◽  
E Coli ◽  
Inner Membrane Protein

The function of cvpA, a bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpA’s genetic interactions and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant’s susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse bacterial phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse bacterial species. IMPORTANCE Several enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse bacterial phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.

scholarly journals The Rcs System in Enterobacteriaceae: Envelope Stress Responses and Virulence Regulation

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiao Meng ◽  
Glenn Young ◽  
Jingyu Chen
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Cell Envelope ◽  
Regulatory System ◽  
Virulence Regulation ◽  
Bacterial Interaction ◽  
Envelope Stress

The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system’s control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.

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