Reaction of a Phospholipid Monolayer with Gas-Phase Ozone at the Air−Water Interface: Measurement of Surface Excess and Surface Pressure in Real Time

Thompson, Katherine C.; Rennie, Adrian R.; King, Martin D.; Hardman, Samantha J. O.; Lucas, Claire O. M.; Pfrang, Christian; Hughes, Brian R.; Hughes, A.

doi:10.1021/la1022714

Cited by 38 publications

(58 citation statements)

References 26 publications

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“…The reaction chamber was mounted on the sample stage, it was interfaced with the gas setup, and the trough was filled with 80 mL of ACMW. A given amount of solution was spread using a microlitre syringe in order to form the monolayer following the protocol used in other NR studies of atmospheric relevance Sebastiani et al, 2015;Skoda et al, 2017;King et al, 2009King et al, , 2010Thompson et al, 2010). The volume of solution spread was 24 µL for d 34 OA, 23 µL for d 14 POA, 32 µL for d 33 MO and 35 µL for d 35 SA.…”

Section: Neutron Reflectometry (Nr)mentioning

confidence: 99%

Nighttime oxidation of surfactants at the air–water interface: effects of chain length, head group and saturation

et al. 2018

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Reactions of the key atmospheric nighttime oxidant NO 3 with organic monolayers at the air-water interface are used as proxies for the ageing of organic-coated aqueous aerosols. The surfactant molecules chosen for this study are oleic acid (OA), palmitoleic acid (POA), methyl oleate (MO) and stearic acid (SA) to investigate the effects of chain length, head group and degree of unsaturation on the reaction kinetics and products formed. Fully and partially deuterated surfactants were studied using neutron reflectometry (NR) to determine the reaction kinetics of organic monolayers with NO 3 at the air-water interface for the first time. Kinetic modelling allowed us to determine the rate coefficients for the oxidation of OA, POA and MO monolayers to be (2.8 ± 0.7) × 10 −8 , (2.4 ± 0.5) × 10 −8 and (3.3 ± 0.6) × 10 −8 cm 2 molecule −1 s −1 for fitted initial desorption lifetimes of NO 3 at the closely packed organic monolayers, τ d,NO 3 ,1 , of 8.1 ± 4.0, 16 ± 4.0 and 8.1 ± 3.0 ns, respectively. The approximately doubled desorption lifetime found in the best fit for POA compared to OA and MO is consistent with a more accessible double bond associated with the shorter alkyl chain of POA facilitating initial NO 3 attack at the double bond in a closely packed monolayer. The corresponding uptake coefficients for OA, POA and MO were found to be (2.1±0.5)×10 −3 , (1.7±0.3)×10 −3 and (2.1±0.4)×10 −3 , respectively. For the much slower NO 3 -initiated oxidation of the saturated surfactant SA we estimated a loss rate of approximately (5 ± 1) × 10 −12 cm 2 molecule −1 s −1 , which we consider to be an upper limit for the reactive loss, and estimated an uptake coefficient of ca. (5 ± 1) × 10 −7 . Our investigations demonstrate that NO 3 will contribute substantially to the processing of unsaturated surfactants at the air-water interface during nighttime given its reactivity is ca. 2 orders of magnitude higher than that of O 3 . Furthermore, the relative contributions of NO 3 and O 3 to the oxidative losses vary massively between species that are closely related in structure: NO 3 reacts ca. 400 times faster than O 3 with the common model surfactant oleic acid, but only ca. 60 times faster with its methyl ester MO. It is therefore necessary to perform a case-by-case assessment of the relative contributions of the different degradation routes for any specific surfactant. The overall impact of NO 3 on the fate of saturated surfactants is slightly less clear given the lack of prior kinetic data for comparison, but NO 3 is likely to contribute significantly to the loss of saturated species and dominate their loss during nighttime. The retention of the organic character at the air-water interface differs fundamentally between the different surfactant species: the fatty acids studied (OA and POA) form products with a yield of ∼ 20 % that are stable at the interface while NO 3 -initiated oxidation of the methyl ester MO rapidly and effectively removes the organic character (≤ 3 % surface-active products). The film-forming potential of r...

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Section: Neutron Reflectometry (Nr)mentioning

confidence: 99%

Nighttime oxidation of surfactants at the air–water interface: effects of chain length, head group and saturation

et al. 2018

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“…Since O 3 is chemically reactive gas, it preferentially induces oxidation of endogenous unsaturated lipids present in pulmonary surfactant. (114,115) It is assumed that the secondary ozonation products, such as lysophospholipids, aldehydes and epoxycholesterol, mediate various cellular responses induced by O 3 . (114,116,117) We recently found that O 3 exposure (6 h, 2 ppm) induced significantly less lung inflammation in Prx1 deficient mice compared to WT mice monitored after 24 h. In bronchoalveolar lavage fluids (BALF), infiltrated immune cell numbers and protein levels of proinflammatory cytokines were significantly less in Prx1 deficient mice compared to WT mice (Yanagisawa et al.…”

Section: Roles Of Prxs In Tissue Inflammationmentioning

confidence: 99%

Novel roles of peroxiredoxins in inflammation, cancer and innate immunity

Ishii

Warabi

Yanagawa

2012

J. Clin. Biochem. Nutr.

129

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Peroxiredoxins possess thioredoxin or glutathione peroxidase and chaperone-like activities and thereby protect cells from oxidative insults. Recent studies, however, reveal additional functions of peroxiredoxins in gene expression and inflammation-related biological reactions such as tissue repair, parasite infection and tumor progression. Notably, peroxiredoxin 1, the major mammalian peroxiredoxin family protein, directly interacts with transcription factors such as c-Myc and NF-κB in the nucleus. Additionally, peroxiredoxin 1 is secreted from some cells following stimulation with TGF-β and other cytokines and is thus present in plasma and body fluids. Peroxiredoxin 1 is now recognized as one of the pro-inflammatory factors interacting with toll-like receptor 4, which triggers NF-κB activation and other signaling pathways to evoke inflammatory reactions. Some cancer cells release peroxiredoxin 1 to stimulate toll-like receptor 4-mediated signaling for their progression. Interestingly, peroxiredoxins expressed in protozoa and helminth may modulate host immune responses partly through toll-like receptor 4 for their survival and progression in host. Extracellular peroxiredoxin 1 and peroxiredoxin 2 are known to enhance natural killer cell activity and suppress virus-replication in cells. Peroxiredoxin 1-deficient mice show reduced antioxidant activities but also exhibit restrained tissue inflammatory reactions under some patho-physiological conditions. Novel functions of peroxiredoxins in inflammation, cancer and innate immunity are the focus of this review.

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“…These reactions may be important in the production of atmospheric SOA, so changes to their nature and kinetics could be important in their own right, however their key relevance comes in that they determine the lifetime and ageing of the monolayer and, thus, the extent to which the water droplet is affected by all the physical and chemical changes detailed above that are due to the presence of that monolayer. Most monolayer studies to date (e.g., [30][31][32][33]) have focused on the less reactive initiator of the atmospheric oxidation ozone (O 3 ) that is known to be unreactive towards saturated surfactants (e.g., [34]). However, saturated surfactants have recently been shown to be of particular atmospheric importance [35], therefore processes that can attack saturated organic compounds are of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Night-Time Oxidation of a Monolayer Model for the Air–Water Interface of Marine Aerosols—A Study by Simultaneous Neutron Reflectometry and in Situ Infra-Red Reflection Absorption Spectroscopy (IRRAS)

et al. 2018

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This paper describes experiments on the ageing of a monolayer model for the air–water interface of marine aerosols composed of a typical glycolipid, galactocerebroside (GCB). Lipopolysaccharides have been observed in marine aerosols, and GCB is used as a proxy for these more complex lipopolysaccharides. GCB monolayers are investigated as pure films, as mixed films with palmitic acid, which is abundant in marine aerosols and forms a stable attractively mixed film with GCB, particularly with divalent salts present in the subphase, and as mixed films with palmitoleic acid, an unsaturated analogue of palmitic acid. Such mixed films are more realistic models of atmospheric aerosols than simpler single-component systems. Neutron reflectometry (NR) has been combined in situ with Fourier transform infra-red reflection absorption spectroscopy (IRRAS) in a pioneering analysis and reaction setup designed by us specifically to study mixed organic monolayers at the air–water interface. The two techniques in combination allow for more sophisticated observation of multi-component monolayers than has previously been possible. The structure at the air–water interface was also investigated by complementary Brewster angle microscopy (BAM). This study looks specifically at the oxidation of the organic films by nitrate radicals (NO3•), the key atmospheric oxidant present at night. We conclude that NO3• oxidation cannot fully remove a cerebroside monolayer from the surface on atmospherically relevant timescales, leaving its saturated tail at the interface. This is true for pure and salt water subphases, as well as for single- and two-component films. The behaviour of the unsaturated tail section of the molecule is more variable and is affected by interactions with co-deposited species. Most surprisingly, we found that the presence of CaCl2 in the subphase extends the lifetime of the unsaturated tail substantially—a new explanation for longer residence times of materials in the atmosphere compared to lifetimes based on laboratory studies of simplified model systems. It is thus likely that aerosols produced from the sea-surface microlayer at night will remain covered in surfactant molecules on atmospherically relevant timescales with impact on the droplet’s surface tension and on the transport of chemical species across the air–water interface.

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Reaction of a Phospholipid Monolayer with Gas-Phase Ozone at the Air−Water Interface: Measurement of Surface Excess and Surface Pressure in Real Time

Cited by 38 publications

References 26 publications

Nighttime oxidation of surfactants at the air–water interface: effects of chain length, head group and saturation

Nighttime oxidation of surfactants at the air–water interface: effects of chain length, head group and saturation

Novel roles of peroxiredoxins in inflammation, cancer and innate immunity

Night-Time Oxidation of a Monolayer Model for the Air–Water Interface of Marine Aerosols—A Study by Simultaneous Neutron Reflectometry and in Situ Infra-Red Reflection Absorption Spectroscopy (IRRAS)

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