stress response envelope

The bundle sheath cell (BSC) layer tightly enveloping the xylem throughout the leaf is recognized as a major signal-perceiving "valve" in series with stomata, regulating leaf hydraulic conductance (Kleaf) and thereby radial water flow via the transpiring leaf. The BSC blue light (BL) signaling pathway increases Kleaf and the underlying BSC water permeability. Here, we explored the hypothesis that BSCs also harbor a Kleaf-downregulating signaling pathway related to the stress phytohormone abscisic acid (ABA)...

Enterococcal infections frequently show high levels of antibiotic resistance, including to cell envelope-acting antibiotics like daptomycin (DAP). While we have a good understanding of the resistance mechanisms, less is known about the control of such resistance genes in enterococci. Previous work unveiled a bacitracin resistance network, comprised of the sensory ABC transporter SapAB, the two-component system (TCS) SapRS and the resistance ABC transporter RapAB. Interestingly, components of this system have recently been implicated in DAP resistance, a role usually regulated by the TCS LiaFSR...

Porcine epidemic diarrhea virus (PEDV) envelope protein (E) has been characterized as an important structural protein that plays critical roles in the interplay with its host to affect the virus life cycle. Stress granules (SGs) are host translationally silent ribonucleoproteins, which are mainly induced by the phosphorylation of eIF2α in the PERK/eIF2α signaling pathway. Our previous study found that PEDV E protein caused endoplasmic reticulum stress response (ERS)-mediated suppression of antiviral proteins' translation...

Systemic acquired resistance protects plants against a broad spectrum of secondary infections by pathogens. A crucial compound involved in the systemic spread of the threat information after primary pathogen infection is the C9 oxylipin azelaic acid (AZA), a breakdown product of unsaturated C18 fatty acids. AZA is generated during lipid peroxidation in the plastids and accumulates in response to various abiotic and biotic stresses. AZA stimulates the expression of AZELAIC ACID INDUCED1 ( AZI1 ), and a pool of AZI1 accumulates in the plastid envelope in association with AZA...

The ability to sense and respond to host defenses is essential for pathogen survival. Some mechanisms involve two-component systems (TCS) that respond to host molecules, such as antimicrobial peptides (AMPs) and activate specific gene regulatory pathways to aid in survival. Alongside TCSs, bacteria coordinate cell division proteins, chaperones, cell wall sortases and secretory translocons at discrete locations within the cytoplasmic membrane, referred to as functional membrane microdomains (FMMs). In Group A Streptococcus (GAS), the FMM or "ExPortal" coordinates protein secretion, cell wall synthesis and sensing of AMP-mediated cell envelope stress via the LiaFSR three-component system...

Air pollution consists of complex mixtures of chemicals with serious deleterious health effects from acute and chronic exposure. To help understand the mechanisms by which adverse effects occur, the present work examines the responses of cultured human epidermal keratinocytes to specific chemicals commonly found in woodsmoke. Our earlier findings with liquid smoke flavoring (aqueous extract of charred wood) revealed that such extracts stimulated the expression of genes associated with oxidative stress and proinflammatory response, activated the aryl hydrocarbon receptor, thereby inducing cytochrome P4501A1 activity, and induced cross-linked envelope formation, a lethal event ordinarily occurring during terminal differentiation...

ADP-ribosylation plays a significant role in various biological processes including genomic stability maintenance, transcriptional regulation, energy metabolism, and cell death. Using macrodomain pull-down assay with microglia lysates and MALDI-TOF-MS analysis, we identified vimentin as a major protein highly ADP-ribosylated by the poly(ADP-ribose) polymerases-1 (PARP-1) in response to LPS. ABT-888, a potent inhibitor of PARP-1/2 blocks the disassembly and ADP-ribosylation of vimentin. PARP-1 is a highly abundant nuclear protein...

Histidine kinases are key bacterial sensors that recognize diverse environmental stimuli. While mechanisms of phosphorylation and phosphotransfer by cytoplasmic kinase domains are relatively well-characterized, the ways in which extracytoplasmic sensor domains regulate activation remain mysterious. The Cpx envelope stress response is a conserved Gram-negative two-component system which is controlled by the sensor kinase CpxA. We report the structure of the Escherichia coli CpxA sensor domain (CpxA-SD) as a globular Per-ARNT-Sim (PAS)-like fold highly similar to that of Vibrio parahaemolyticus CpxA as determined by X-ray crystallography...

Enterococci have evolved resistance mechanisms to protect their cell envelopes against bacteriocins and host cationic antimicrobial peptides (CAMPs) produced in the gastrointestinal environment. Activation of the membrane stress response has also been tied to resistance to the lipopeptide antibiotic daptomycin. However, the actual effectors mediating resistance have not been elucidated. Here, we show that the MadRS (formerly YxdJK) membrane antimicrobial peptide defense system controls a network of genes, including a previously uncharacterized three gene operon (madEFG) that protects the E...

Global burden of infectious diseases and antimicrobial resistance are major public health issues calling for innovative control measures. Bacterial NAD kinase (NADK) is a crucial enzyme for production of NADP(H) and growth. In Staphylococcus aureus, NADK promotes pathogenesis by supporting production of key virulence determinants. Here, we find that knockdown of NADK by CRISPR interference sensitizes S. aureus to osmotic stress and to stresses induced by antibiotics targeting the envelop as well as replication, transcription and translation...

UNLABELLED: Pseudomonas aeruginosa is an opportunistic pathogen causing chronic infections that are related to its ability to form biofilms. Mechanosensitive ion channels (Mcs) are cytoplasmic membrane proteins whose opening depends on a mechanical stress impacting the lipid bilayer. CmpX is a homologue of the small conductance MscS of Escherichia coli . The cmpX gene is part of a transcriptional cfrX-cmpX unit that is under the control of the cell envelope stress response ECF sigma factor SigX...

Chlorhexidine (CHX) is widely considered to be the gold standard for preventing dental caries. However, it is possible to induce resistance to CHX. The LiaSR two-component system has been identified that contributed to CHX resistance in Streptococcus mutans , which is one of the major pathogens in dental caries. However, the underlying mechanisms remain unclear. In this study, an MIC assay and a viability assessment demonstrated that after deleting the liaS and liaR genes, the sensitivity of mutants could increase...

Severe cardiac remodeling leading to heart failure in individuals harboring pathogenic LMNA variants, known as cardiolaminopathy, poses a significant clinical challenge. Currently, there is no effective treatment for lamin-related diseases. Exploring the intricate molecular landscape underlying this condition, with a specific focus on abnormal mechanotransduction, will propel our understanding of cardiolaminopathy. The LMNA gene undergoes alternative splicing to create A-type lamins, a part of the intermediate filament protein family...

Salmonella enterica serovar Typhimurium ( S . Typhimurium) controls lipopolysaccharide (LPS) biosynthesis by regulating proteolysis of LpxC, the rate-limiting enzyme and target of preclinical antibiotics. PbgA/YejM/LapC regulates LpxC levels and controls outer membrane (OM) LPS composition at the log-to-stationary phase transition. Suppressor substitutions in <u>L</u>PS <u>a</u>ssembly <u>p</u>rotein <u>B</u> (LapB/YciM) rescue the LPS and OM integrity defects of pbgA -mutant S ...

The cssR gene ( ncgl1578 ) of Corynebacterium glutamicum encodes a repressor of the TetR (tetracycline regulator) family. Its role in the stress response to antibiotics/heavy metals has been investigated, but how CssR functions in response to phenolic compounds in C. glutamicum has been rarely studied. In this study, we applied transcriptomic analysis, β-galactosidase analysis, qRT-PCR, and EMSAs to analyze the target genes and functions of CssR in response to phenolic compounds. Consistent with the upregulation of genes involved in the degradation of phenolic compounds, the Δ cssR mutant was more resistant to various phenolic compounds than was the wild-type strain...

Plastids are organelles playing fundamental roles in different cellular processes such as energy metabolism or lipid biosynthesis. To fulfill their biogenesis and their function in the cell, plastids have to communicate with other cellular compartments. This communication can be mediated by the establishment of direct contact sites between plastids envelop and other organelles. These contacts are dynamic structures regulated in response to stress. For example, during phosphate (Pi) starvation, the number of contact sites between plastids and mitochondria significantly increases...

Plastids are organelles delineated by two envelopes playing important roles in different cellular processes such as energy production or lipid biosynthesis. To regulate their biogenesis and their function, plastids have to communicate with other cellular compartments. This communication can be mediated by metabolites, signaling molecules, and by the establishment of direct contacts between the plastid envelope and other organelles such as the endoplasmic reticulum, mitochondria, peroxisomes, plasma membrane, and the nucleus...

The unsatisfactory properties of ceramic aerogels when subjected to thermal shock, such as strength degradation and structural collapse, render them unsuitable for use at large thermal gradients or prolonged exposure to extreme temperatures. Here we present a building-envelope-inspired design for fabricating a thermomechanically robust all-fiber ceramic meta-aerogel with interlocked fibrous interfaces and an interwoven cellular structure in the orthogonal directions, which is achieved through a two-stage physical and chemical process...

Biogenesis of the outer membrane (OM) of Gram-negative bacteria involves two processes essential for growth, that is, the insertion of β-barrel outer membrane proteins (OMPs) by the Bam complex and the assembly of the LPS-containing outer leaflet of the OM by the LptD/E complex from the Lpt pathway. These processes have only recently gained attention as targets for antimicrobial drugs. Our laboratory has developed a simple screening tool to identify compounds that target processes that disrupt the biogenesis of the cell envelope, among which the activity of the Bam complex...

UNLABELLED: Two growth modes have been described for the filamentous Streptomyces bacteria. Their classic developmental life cycle culminates in the formation of dormant spores, where movement to new environments is mediated through spore dispersal. In contrast, exploratory growth proceeds as a rapidly expanding vegetative mycelium that leads to extensive surface colonization and is associated with the release of volatile compounds that promote alkalinization (and reduced iron bioavailability) of its surrounding environment...