scholarly journals Modulation of sensory perception by hydrogen peroxide enables Caenorhabditis elegans to find a niche that provides both food and protection from hydrogen peroxide

2021 ◽  
Author(s):  
Jodie A. Schiffer ◽  
Stephanie V. Stumbur ◽  
Maedeh Seyedolmohadesin ◽  
Yuyan Xu ◽  
William T. Serkin ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Bacterial Communities ◽  
Food Preference ◽  
Sensory Perception ◽  
General Mechanism ◽  
Safe Environment ◽  
Degrading Enzymes ◽  
Bacterial Food

SummaryHydrogen peroxide (H2O2) is the most common chemical threat that organisms face. Here, we show that H2O2 alters the bacterial food preference of Caenorhabditis elegans, enabling the nematodes to find a safe environment with food. H2O2 induces the nematodes to leave food patches of laboratory and microbiome bacteria when those bacterial communities have insufficient H2O2-degrading capacity. The nematode’s behavior is directed by H2O2-sensing neurons that promote escape from H2O2 and by bacteria-sensing neurons that promote attraction to bacteria. However, the input for H2O2-sensing neurons is removed by bacterial H2O2-degrading enzymes and the bacteria-sensing neurons’ perception of bacteria is prevented by H2O2. The resulting cross-attenuation provides a general mechanism that ensures the nematode’s behavior is faithful to the lethal threat of hydrogen peroxide, increasing the nematode’s chances of finding a niche that provides both food and protection from hydrogen peroxide.

scholarly journals Modulation of sensory perception by hydrogen peroxide enables Caenorhabditis elegans to find a niche that provides both food and protection from hydrogen peroxide

2021 ◽  
Vol 17 (12) ◽  
pp. e1010112
Author(s):  
Jodie A. Schiffer ◽  
Stephanie V. Stumbur ◽  
Maedeh Seyedolmohadesin ◽  
Yuyan Xu ◽  
William T. Serkin ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Bacterial Communities ◽  
Food Preference ◽  
Sensory Perception ◽  
General Mechanism ◽  
Safe Environment ◽  
Degrading Enzymes ◽  
Bacterial Food

Hydrogen peroxide (H2O2) is the most common chemical threat that organisms face. Here, we show that H2O2 alters the bacterial food preference of Caenorhabditis elegans, enabling the nematodes to find a safe environment with food. H2O2 induces the nematodes to leave food patches of laboratory and microbiome bacteria when those bacterial communities have insufficient H2O2-degrading capacity. The nematode’s behavior is directed by H2O2-sensing neurons that promote escape from H2O2 and by bacteria-sensing neurons that promote attraction to bacteria. However, the input for H2O2-sensing neurons is removed by bacterial H2O2-degrading enzymes and the bacteria-sensing neurons’ perception of bacteria is prevented by H2O2. The resulting cross-attenuation provides a general mechanism that ensures the nematode’s behavior is faithful to the lethal threat of hydrogen peroxide, increasing the nematode’s chances of finding a niche that provides both food and protection from hydrogen peroxide.

scholarly journals Hydrogen Peroxide-Mediated Killing of Caenorhabditis elegans by Streptococcus pyogenes

2002 ◽  
Vol 70 (9) ◽  
pp. 5202-5207 ◽  
Author(s):  
W. T. M. Jansen ◽  
M. Bolm ◽  
R. Balling ◽  
G. S. Chhatwal ◽  
R. Schnabel
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Streptococcus Pyogenes ◽  
Wide Spectrum ◽  
Model Organism ◽  
Common Mechanism ◽  
Gram Positive ◽  
C Elegans ◽  
Gram Positive Bacteria ◽  
Serovar Typhimurium

ABSTRACT Caenorhabditis elegans is currently introduced as a new, facile, and cheap model organism to study the pathogenesis of gram-negative bacteria such as Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium. The mechanisms of killing involve either diffusible exotoxins or infection-like processes. Recently, it was shown that also some gram-positive bacteria kill C. elegans, although the precise mechanisms of killing remained open. We examined C. elegans as a pathogenesis model for the gram-positive bacterium Streptococcus pyogenes, a major human pathogen capable of causing a wide spectrum of diseases. We demonstrate that S. pyogenes kills C. elegans, both on solid and in liquid medium. Unlike P. aeruginosa and S. enterica serovar Typhimurium, the killing by S. pyogenes is solely mediated by hydrogen peroxide. Killing required live streptococci; the killing capacity depends on the amount of hydrogen peroxide produced, and killing can be inhibited by catalase. Major exotoxins of S. pyogenes are not involved in the killing process as confirmed by using specific toxin inhibitors and knockout mutants. Moreover, no accumulation of S. pyogenes in C. elegans is observed, which excludes the involvement of infection-like processes. Preliminary results show that S. pneumoniae can also kill C. elegans by hydrogen peroxide production. Hydrogen peroxide-mediated killing might represent a common mechanism by which gram-positive, catalase-negative pathogens kill C. elegans.

scholarly journals Proteomics reveals synergy between biomass degrading enzymes and inorganic Fenton chemistry in leaf-cutting ant colonies

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Morten Schiøtt ◽  
Jacobus J Boomsma
Keyword(s):  
Hydrogen Peroxide ◽  
Plant Cell Wall ◽  
Plant Biomass ◽  
Biomass Degradation ◽  
Ant Colonies ◽  
Fenton Chemistry ◽  
Degrading Enzymes ◽  
Biochemical Assays ◽  
Oxidized Iron ◽  
Leaf Cutting

The symbiotic partnership between leaf-cutting ants and fungal cultivars processes plant biomass via ant fecal fluid mixed with chewed plant substrate before fungal degradation. Here we present a full proteome of the fecal fluid of Acromyrmex leaf-cutting ants, showing that most proteins function as biomass degrading enzymes and that ca. 85% are produced by the fungus and ingested, but not digested, by the ants. Hydrogen peroxide producing oxidoreductases were remarkably common in the proteome, inspiring us to test a scenario in which hydrogen peroxide reacts with iron to form reactive oxygen radicals after which oxidized iron is reduced by other fecal-fluid enzymes. Our biochemical assays confirmed that these so-called Fenton reactions do indeed take place in special substrate pellets, presumably to degrade plant cell wall polymers. This implies that the symbiotic partnership manages a combination of oxidative and enzymatic biomass degradation, an achievement that surpasses current human bioconversion technology.

Hydrogen peroxide-mediated killing of Caenorhabditis elegans by Enterococcus italicus and Lactococcus garvieae isolated from food

2014 ◽  
Vol 65 (2) ◽  
pp. 833-839 ◽  
Author(s):  
Francesca Borgo ◽  
Francesco Ballestriero ◽  
Chiara Ferrario ◽  
Maria Grazia Fortina
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Lactococcus Garvieae ◽  
Enterococcus Italicus

scholarly journals Acute exposure to a glyphosate-containing herbicide formulation inhibits Complex II and increases hydrogen peroxide in the model organism Caenorhabditis elegans

2019 ◽  
Vol 66 ◽  
pp. 36-42 ◽  
Author(s):  
Shelbie L. Burchfield ◽  
Denise C. Bailey ◽  
Callie E. Todt ◽  
Rachel D. Denney ◽  
Rekek Negga ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Model Organism ◽  
Acute Exposure ◽  
Complex Ii

scholarly journals Novel Polymeric Nanocarriers Reduced Zinc and Doxycycline Toxicity in the Nematode Caenorhabditis elegans

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 550 ◽  
Author(s):  
Manuel Toledano ◽  
Manuel Toledano-Osorio ◽  
María D. Navarro-Hortal ◽  
Alfonso Varela-López ◽  
Raquel Osorio ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Death Rate ◽  
Polymeric Nanoparticles ◽  
Model Organism ◽  
Polymeric Nanocarriers ◽  
Pharyngeal Pumping ◽  
Species Production ◽  
Intracellular Hydrogen Peroxide

The objective was to evaluate the toxicity of zinc- and doxycycline-loaded polymeric nanoparticles (NPs) using Caenorhabditis elegans as a model organism. These NPs are composed of ethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate and methacrylic acid. NPs were loaded with doxycycline (D-NPs) and zinc (Zn-NPs) by chemical adsorption, and loading efficacy was demonstrated. Worm death rate in a concentration-response curve basis was calculated for lethality. Metabolism was evaluated through pharyngeal pumping assay. Body length measurements, brood size and egg lays were used to gauge growth, reproduction and fertility respectively. Intracellular hydrogen peroxide levels were determined to assess the reactive oxygen species production. One-way ANOVA and Bonferroni were used for comparisons (p < 0.05). Tested NPs at the highest dosage did not affect lethality or worm metabolism, expressed in terms of death rate and pharyngeal pumping per minute, respectively. Zn-NPs slightly increased worm growth. The concentration of the intracellular hydrogen peroxide levels was the lowest in the D-NPs group. The distinct NPs and concentrations employed were shown to be non-toxic for in situ administration of zinc and doxycycline, reducing the harmful effects of these compounds.

Titration Study of Guaiarcol Oxidation by Horseradish Peroxidase

1975 ◽  
Vol 53 (6) ◽  
pp. 649-657 ◽  
Author(s):  
Marius Santimone
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Low Temperature ◽  
Horseradish Peroxidase ◽  
Catalytic Amount ◽  
Reaction Scheme ◽  
General Mechanism ◽  
Compound I ◽  
Compound Ii ◽  
Titration Study

Titration of guaiacol by hydrogen peroxide in the presence of a catalytic amount of horseradish peroxidase shows that the reduction of hydrogen peroxide proceeds by the abstraction of two electrons from a guaiacol molecule. In the same way, it can be demonstrated that 0.5 mol of guaiacol can reduce, at low temperature, 1 mol of peroxidase compound I to compound II. Moreover, the reaction between equal amounts of compound I and guaiacol at low temperature produces the native enzyme. A reaction scheme is proposed which postulates that two electrons are transferred from guaiacol to compound I giving ferriperoxidase and oxidized guaiacol with the intermediary formation of compound II. The direct two-electron transfer from guaiacol to compound I without a dismutation of product free radicals must be considered as an exception to the general mechanism involving a single-electron transfer.

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