The Effect of Cigarette Smoking on Hydrogen Peroxide-degrading Enzymes in Human Saliva

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.

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

eLife ◽

10.7554/elife.61816 ◽

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.

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

PLoS Pathogens ◽

10.1371/journal.ppat.1010112 ◽

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.

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Excess Iodine Exposure Acutely Increases Salivary Iodide And Antimicrobial Hypoiodous Acid Concentrations In Humans

10.21203/rs.3.rs-1157474/v1 ◽

2021 ◽

Author(s):

Yasutada Akiba ◽

Angela M. Leung ◽

Muhammad-Tariq Bashir ◽

Ramin Ebrahimi ◽

Jesse W. Currier ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Human Saliva ◽

Influenza Viruses ◽

Contrast Injection ◽

Viral Pathogens ◽

Excess Iodine ◽

Microbial Invasion ◽

Iodinated Contrast ◽

Before And After ◽

Baseline Levels

Abstract The lactoperoxidase (LPO)-hydrogen peroxide-halides reaction (LPO system) converts iodide and thiocyanate (SCN-) into hypoiodous acid (HOI) and hypothiocyanite (OSCN-), respectively. Since this system has been implicated in defense of the airways and oropharynx from microbial invasion, we measured the concentrations of these analytes in human saliva before and after iodine administration to test the hypothesis that an iodide load increases salivary iodide and HOI concentrations. Salivary iodide, SCN-, HOI and OSCN- were measured using standard methodology. Salivary iodide and HOI levels significantly increased after iodinated contrast injection compared with baseline levels, whereas there was no significant change in salivary SCN- and OSCN- levels. The contrast dye iodine load and changes of salivary iodide and HOI levels were positively correlated, suggesting that higher iodide in the circulation increases iodide output and salivary HOI production. Excess iodine exposure in humans increases the salivary output of iodide, increasing salivary HOI concentrations with no effect on SCN-/OSCN- levels. This first of its kind study suggests that a sufficient but safe iodide supplementation may augment the generation of antimicrobial HOI by the salivary LPO system against airborne viral pathogens, including coronaviruses and influenza viruses, a possible inexpensive means of effectively curbing viral pandemics.

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Hydrogen peroxide-induced changes in activities of membrane lipids-degrading enzymes and contents of membrane lipids composition in relation to pulp breakdown of longan fruit during storage

Food Chemistry ◽

10.1016/j.foodchem.2019.124955 ◽

2019 ◽

Vol 297 ◽

pp. 124955 ◽

Cited By ~ 11

Author(s):

Yixiong Lin ◽

Hetong Lin ◽

Yihui Chen ◽

Hui Wang ◽

Mark A. Ritenour ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Membrane Lipids ◽

Degrading Enzymes ◽

Induced Changes

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Bacterial chemotactic peptide-degrading enzymes in human saliva

Journal of Periodontal Research ◽

10.1111/j.1600-0765.1988.tb01366.x ◽

1988 ◽

Vol 23 (4) ◽

pp. 245-247

Author(s):

M. M. Ferguson ◽

D. M. Mellor ◽

K. Morris ◽

V. S. Chadwick

Keyword(s):

Human Saliva ◽

Chemotactic Peptide ◽

Degrading Enzymes

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Differential effect of cigarette smoking on hydrogen peroxide and thiobarbituric acid reactive substances exhaled in patients with community acquired pneumonia

Monaldi Archives for Chest Disease ◽

10.4081/monaldi.2006.581 ◽

2016 ◽

Vol 65 (1) ◽

Cited By ~ 1

Author(s):

R.A. Stolarek ◽

M. Kasielski ◽

J. Rysz ◽

P. Bialasiewicz ◽

D. Nowak

Keyword(s):

Hydrogen Peroxide ◽

Cigarette Smoking ◽

Smoking Status ◽

Community Acquired Pneumonia ◽

Smoking History ◽

Hospital Treatment ◽

Exhaled Breath ◽

Entire Study ◽

H2o2 Decomposition ◽

Breath Condensate

Background. This study was designed to investigate the effect of cigarette smoking on hydrogen peroxide (H2O2) and thiobarbituric reactive substances (TBARs) concentrations in exhaled breath condensate (EBC) in patients with community acquired pneumonia (CAP). Methods. H2O2 and TBARs concentrations in EBC were determined with spectrofluorimetrical assays. Results. Non-smoking CAP patients (n=24) exhaled 1.4, 1.8 and 1.7 times more H2O2 than the smoking patients with CAP (n=19) as assessed one (0.73±0.32 μM v. 0.51±0.36 μM), three (0.84±0.31 μM v. 0.47±0.24 μM) and five (0.66±0.28 μM v. 0.40±0.35 μM) days after admission (p<0.05 in each case). Over 10 days of hospital treatment, mean level of exhaled H2O2 0.45±0.22 μM in CAP patients with smoking history was decreased if compared with 0.71±0.19 μM exhaled H2O2 in CAP group (p=0.005). On the contrary, TBARs concentration evaluated over entire study period was increased in smoking CAP patients (median 0.02 μM, range 0-0.32 μM) compared with non-smoking group (median 0.01 μM, range 0-0.21 μM, p<0.05). Concurrent, active smoking status was related with the decreased levels of H2O2 exhaled in breath condensate within the course of CAP but it appeared to increase levels of TBARs. Conclusions. The differential alternations of oxidative parameters in EBC with respect to the smoking status might provide evidence of increased H2O2 decomposition and enhanced generation of reactive species in airways of CAP patients.

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