Characteristics of stress response in a mushroom-pathogenic bacterium, Pseudomonas tolaasii, during the interaction with Pleurotus ostreatus and carbon/nitrogen starvation in vitro

Mycoscience ◽  
1999 ◽  
Vol 40 (1) ◽  
pp. 81-85 ◽  
Author(s):  
Hitoshi Murata
Keyword(s):  
Stress Response ◽  
Pleurotus Ostreatus ◽  
Nitrogen Starvation ◽  
Pathogenic Bacterium ◽  
Pseudomonas Tolaasii

CarR, a MarR-family regulator from Corynebacterium glutamicum, modulated antibiotic and aromatic compound resistance

2019 ◽  
Vol 476 (21) ◽  
pp. 3141-3159 ◽  
Author(s):  
Meiru Si ◽  
Can Chen ◽  
Zengfan Wei ◽  
Zhijin Gong ◽  
GuiZhi Li ◽  
...  
Keyword(s):  
Stress Response ◽  
Ligand Binding ◽  
Corynebacterium Glutamicum ◽  
Conformational Changes ◽  
Cysteine Oxidation ◽  
Transcriptional Regulatory ◽  
Ligand Free ◽  
Redox Sensing

Abstract MarR (multiple antibiotic resistance regulator) proteins are a family of transcriptional regulators that is prevalent in Corynebacterium glutamicum. Understanding the physiological and biochemical function of MarR homologs in C. glutamicum has focused on cysteine oxidation-based redox-sensing and substrate metabolism-involving regulators. In this study, we characterized the stress-related ligand-binding functions of the C. glutamicum MarR-type regulator CarR (C. glutamicum antibiotic-responding regulator). We demonstrate that CarR negatively regulates the expression of the carR (ncgl2886)–uspA (ncgl2887) operon and the adjacent, oppositely oriented gene ncgl2885, encoding the hypothetical deacylase DecE. We also show that CarR directly activates transcription of the ncgl2882–ncgl2884 operon, encoding the peptidoglycan synthesis operon (PSO) located upstream of carR in the opposite orientation. The addition of stress-associated ligands such as penicillin and streptomycin induced carR, uspA, decE, and PSO expression in vivo, as well as attenuated binding of CarR to operator DNA in vitro. Importantly, stress response-induced up-regulation of carR, uspA, and PSO gene expression correlated with cell resistance to β-lactam antibiotics and aromatic compounds. Six highly conserved residues in CarR were found to strongly influence its ligand binding and transcriptional regulatory properties. Collectively, the results indicate that the ligand binding of CarR induces its dissociation from the carR–uspA promoter to derepress carR and uspA transcription. Ligand-free CarR also activates PSO expression, which in turn contributes to C. glutamicum stress resistance. The outcomes indicate that the stress response mechanism of CarR in C. glutamicum occurs via ligand-induced conformational changes to the protein, not via cysteine oxidation-based thiol modifications.

scholarly journals Lysosomotropic agents including azithromycin, chloroquine and hydroxychloroquine activate the integrated stress response

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ai-Ling Tian ◽  
Qi Wu ◽  
Peng Liu ◽  
Liwei Zhao ◽  
Isabelle Martins ◽  
...  
Keyword(s):  
Stress Response ◽  
Immune Responses ◽  
Initiation Factor ◽  
Integrated Stress Response ◽  
Serine Residue ◽  
Eif2α Phosphorylation ◽  
Lysosomotropic Agents ◽  
Cultured Human Cells

AbstractThe integrated stress response manifests with the phosphorylation of eukaryotic initiation factor 2α (eIF2α) on serine residue 51 and plays a major role in the adaptation of cells to endoplasmic reticulum stress in the initiation of autophagy and in the ignition of immune responses. Here, we report that lysosomotropic agents, including azithromycin, chloroquine, and hydroxychloroquine, can trigger eIF2α phosphorylation in vitro (in cultured human cells) and, as validated for hydroxychloroquine, in vivo (in mice). Cells bearing a non-phosphorylatable eIF2α mutant (S51A) failed to accumulate autophagic puncta in response to azithromycin, chloroquine, and hydroxychloroquine. Conversely, two inhibitors of eIF2α dephosphorylation, nelfinavir and salubrinal, enhanced the induction of such autophagic puncta. Altogether, these results point to the unexpected capacity of azithromycin, chloroquine, and hydroxychloroquine to elicit the integrated stress response.

scholarly journals The acute transcriptional responses to dietary methionine restriction are triggered by inhibition of ternary complex formation and linked to Erk1/2, mTOR, and ATF4

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kirsten P. Stone ◽  
Sujoy Ghosh ◽  
Jean Paul Kovalik ◽  
Manda Orgeron ◽  
Desiree Wanders ◽  
...  
Keyword(s):  
Stress Response ◽  
Complex Formation ◽  
Ternary Complex ◽  
Target Genes ◽  
Bioinformatic Analysis ◽  
Transcriptional Responses ◽  
Metabolomics Data ◽  
Ternary Complex Formation ◽  
Methionine Restriction

AbstractThe initial sensing of dietary methionine restriction (MR) occurs in the liver where it activates an integrated stress response (ISR) that quickly reduces methionine utilization. The ISR program is regulated in part by ATF4, but ATF4’s prototypical upstream regulator, eIF2α, is not acutely activated by MR. Bioinformatic analysis of RNAseq and metabolomics data from liver samples harvested 3 h and 6 h after initiating MR shows that general translation is inhibited at the level of ternary complex formation by an acute 50% reduction of hepatic methionine that limits formation of initiator methionine tRNA. The resulting ISR is induced by selective expression of ATF4 target genes that mediate adaptation to reduced methionine intake and return hepatic methionine to control levels within 4 days of starting the diet. Complementary in vitro experiments in HepG2 cells after knockdown of ATF4, or inhibition of mTOR or Erk1/2 support the conclusion that the early induction of genes by MR is partially dependent on ATF4 and regulated by both mTOR and Erk1/2. Taken together, these data show that initiation of dietary MR induces an mTOR- and Erk1/2-dependent stress response that is linked to ATF4 by the sharp, initial drop in hepatic methionine and resulting repression of translation pre-initiation.

scholarly journals The Cellular Senescence Stress Response in Post-Mitotic Brain Cells: Cell Survival at the Expense of Tissue Degeneration

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 229
Author(s):  
Eric Sah ◽  
Sudarshan Krishnamurthy ◽  
Mohamed Y. Ahmidouch ◽  
Gregory J. Gillispie ◽  
Carol Milligan ◽  
...  
Keyword(s):  
Stress Response ◽  
Cell Fate ◽  
Cellular Senescence ◽  
Cell Biology ◽  
Brain Aging ◽  
Complex Stress ◽  
Brain Cell ◽  
Tissue Degeneration ◽  
Cellular Dna

In 1960, Rita Levi-Montalcini and Barbara Booker made an observation that transformed neuroscience: as neurons mature, they become apoptosis resistant. The following year Leonard Hayflick and Paul Moorhead described a stable replicative arrest of cells in vitro, termed “senescence”. For nearly 60 years, the cell biology fields of neuroscience and senescence ran in parallel, each separately defining phenotypes and uncovering molecular mediators to explain the 1960s observations of their founding mothers and fathers, respectively. During this time neuroscientists have consistently observed the remarkable ability of neurons to survive. Despite residing in environments of chronic inflammation and degeneration, as occurs in numerous neurodegenerative diseases, often times the neurons with highest levels of pathology resist death. Similarly, cellular senescence (hereon referred to simply as “senescence”) now is recognized as a complex stress response that culminates with a change in cell fate. Instead of reacting to cellular/DNA damage by proliferation or apoptosis, senescent cells survive in a stable cell cycle arrest. Senescent cells simultaneously contribute to chronic tissue degeneration by secreting deleterious molecules that negatively impact surrounding cells. These fields have finally collided. Neuroscientists have begun applying concepts of senescence to the brain, including post-mitotic cells. This initially presented conceptual challenges to senescence cell biologists. Nonetheless, efforts to understand senescence in the context of brain aging and neurodegenerative disease and injury emerged and are advancing the field. The present review uses pre-defined criteria to evaluate evidence for post-mitotic brain cell senescence. A closer interaction between neuro and senescent cell biologists has potential to advance both disciplines and explain fundamental questions that have plagued their fields for decades.

scholarly journals Toxin Production by Pseudomonas Tolaasii Paine

1973 ◽  
Vol 26 (2) ◽  
pp. 509 ◽  
Author(s):  
NG Nair ◽  
PC Fahy
Keyword(s):  
Toxin Production ◽  
Nutrient Broth ◽  
Dialysis Membrane ◽  
Pseudomonas Tolaasii ◽  
Brown Discoloration

Evidence is presented for the production of toxin in vitro and in vivo by P. tolaasii. Nutrient broth suspensions of P. tolaasii placed on detached mushroom sporophores but separated by a dialysis membrane caused brown discoloration and slightly sunken lesions.

Difference of MreBCD Complex Interactome in Salmonella Typhimurium ST19 and ST213 Genotypes on Pathogenesis and Stress Response Pathways

2021 ◽  
Vol 22 ◽  
Author(s):  
Reyna Cristina Zepeda-Gurrola ◽  
Gerardo Vázquez-Marrufo ◽  
Xianwu Guo ◽  
Isabel Cristina Rodríguez-Luna ◽  
Alejandro Sánchez-Varela ◽  
...  
Keyword(s):  
Stress Response ◽  
Bacterial Virulence ◽  
Eukaryotic Cells ◽  
Interaction Patterns ◽  
High Infection Rate ◽  
Differential Interaction ◽  
Sequence Variations ◽  
High Infection ◽  
Underlying Mechanisms

: Salmonella enterica is the etiological agent of salmonellosis, with a high infection rate worldwide. In Mexico, ST213 genotype of S. enterica ser. Typhimurium is displacing the ancestral ST19 genotype. Bacterial cytoskeleton protein complex MreBCD play an important role in S. enterica pathogenesis, but underlying mechanisms are unknown. In this study, 106 interactions among MreBCD and 15 proteins from S. Typhimurium Pathogenicity Islands 1 (SP-I) and 2 (SP-2) involved in both bacterial virulence and stress response were predicted in ST213 and ST19 genotypes, of which 12 interactions were confirmed in vitro. In addition, gene cluster analysis in 100 S. Typhimurium genomes was performed for these genes. The in silico and in vitro results showed a novel MreBCD interactome involved in the regulation of pathogenesis and stress response through interactions with virulence factors located at SPI-1 and SPI-2. Furthermore, both pseudogene presence and sequence variations in four tested proteins between genotypes resulted in differential interaction patterns that are involved in Salmonella motility and survival in eukaryotic cells, which could explain replacement of ST19 by ST213 in Mexico.

DEGRADAÇÃO DA MADEIRA DE EUCALYPTUS SP. POR BASIDIOMICETOS DE PODRIDÃO BRANCA

2007 ◽  
Vol 74 (4) ◽  
pp. 321-328
Author(s):  
L.D. Abreu ◽  
R.H. Marino ◽  
J.B. Mesquita ◽  
G.T. Ribeiro
Keyword(s):  
Pleurotus Ostreatus ◽  
Schizophyllum Commune ◽  
Pycnoporus Cinnabarinus

RESUMO Avaliou-se a degradação de Eucalyptus sp. pelos basidiomicetos Pleurotus ostreatus, Pycnoporus cinnabarinus e Schizophyllum commune, in vitro e em condições de campo. Para tanto, na degradação in vitro foram utilizados discos de Eucalyptus sp. submetidos aos seguintes tratamentos: T1 controle; T2 – 5 mL de água; T3 – 10 mL de água; T4 meio de cultura batata-dextrose-ágar. O parâmetro analisado foi a perda de massa (em %), após 60 e 120 dias de incubação. Em condições de campo foram utilizados corpos de prova deEucalyptus sp. inoculados com substrato “spawn” dePleurotusostreatus, Pycnoporus cinnabarinus e Schizophyllum commune. Foram realizados os seguintes tratamentos: T1 – controle (sem água e sem inóculo); T2 – corpos de prova submersos por 24h em água e T3 – corpos de prova não submersos por 24h em água e avaliada a perda de massa (%), após 60 e 120 dias de incubação. A degradação dos discos de eucalipto in vitro e em condições de campo foi influenciada pelos isolados. Os discos de eucalipto, in vitro, inoculados com Pycnoporus cinnabarinus apresentaram, em média, 25,33% de perda de massa e o micélio foi mais vigoroso em relação ao isolado Pleurotus ostreatus e ao Schizophyllum commune. Os tratamentos empregados e o período de incubação, in vitro, não influenciaram a perda de massa dos discos de eucalipto. Em condições de campo, a perda de massa dos corpos de prova de eucalipto, inoculados com Pycnoporus cinnabarinus, foi de 15,79%, já com Pleurotus ostreatus foi de 12,45% e Schizophyllum commune 12,95%.

scholarly journals Papel de la vitamina C y los β-glucanos sobre el sistema inmunitario: revisión

2015 ◽  
Vol 19 (4) ◽  
pp. 238
Author(s):  
Ismael San Mauro-Martín ◽  
Elena Garicano Vilar
Keyword(s):  
Natural Killer ◽  
Pleurotus Ostreatus ◽  
El Sistema

Existe un creciente interés en conocer herramientas nutricionales al alcance de profesionales para el manejo de la modulación del sistema inmunitario del humano. Esta revisión bibliográfica se centra en los potenciales efectos beneficiosos sobre el sistema inmune atribuidos a productos alimenticios compuestos por β-glucanos de Pleurotus ostreatus, y/o Vitamina C. Este trabajo muestra el resultado obtenido en diferentes estudios con la ingesta de estos componentes sobre el sistema inmunitario, así como el efecto específico sobre marcadores inmunitarios como las interleuquinas, los linfocitos, células Natural Killer y los leucocitos, no sólo atendiendo a los mecanismos, sino a las experiencias en modelos in vitro e in vivo (animal y humano). Tanto la vitamina C como los β-glucanos parecen mostrar eficacia sobre el sistema inmune en diversos estudios, especialmente de forma conjunta, pero son necesarios más estudios.

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