Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sclerotinia sclerotiorum, a pathogen of more than 600 host plants, secretes oxalic acid to regulate the ambient acidity and provide conducive environment for pathogenicity and reproduction. Few Aspergillus spp. were previously proposed as potential biocontrol agents for S. sclerotiorum as they deteriorate sclerotia and prevent pathogen's overwintering and initial infections. We studied the nature of physical and biochemical interactions between Aspergillus and Sclerotinia. Aspergillus species inhibited sclerotial germination as they colonized its rind layer. However, Aspergillus-infested sclerotia remain solid and viable for vegetative and carpogenic germination, indicating that Aspergillus infestation is superficial. Aspergillus spp. of section Nigri (Aspergillus japonicus and Aspergillus niger) were also capable of suppressing sclerotial formation by S. sclerotiorum on agar plates. Their culture filtrate contained high levels of oxalic, citric and glutaric acids comparing to the other Aspergillus spp. tested. Exogenous supplementation of oxalic acid altered growth and reproduction of S. sclerotiorum at low concentrations. Inhibitory concentrations of oxalic acid displayed lower pH values comparing to their parallel concentrations of other organic acids. Thus, S. sclerotiorum growth and reproduction are sensitive to the ambient oxalic acid fluctuations and the environmental acidity. Together, Aspergillus species parasitize colonies of Sclerotinia and prevent sclerotial formation through their acidic secretions.
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PMID:Aspergillus spp. eliminate Sclerotinia sclerotiorum by imbalancing the ambient oxalic acid concentration and parasitizing its sclerotia. 3284 37

To eliminate the spread of a novel coronavirus breaking out in the end of 2019 (COVID-19), the Chinese government has implemented a nationwide lockdown policy after the Chinese lunar New Year of 2020, resulting in a sharp reduction in air pollutant emissions. To investigate the impact of the lockdown on aerosol chemistry, the number fraction, size distribution and formation process of oxalic acid (C2) containing particles and its precursors were studied using a single particle aerosol mass spectrometer (SPAMS) at the urban site of Liaocheng in the North China Plain (NCP). Our results showed that five air pollutants (i.e., PM2.5, PM10, SO2, NO2, and CO) decreased by 30.0-59.8% during the lockdown compared to those before the lockdown, while O3 increased by 63.9% during the lockdown mainly due to the inefficient titration effect of O3 via NO reduction. The increased O3 concentration can boost the atmospheric oxidizing capacity and further enhance the formation of secondary organic aerosols, thereby significantly enhancing the C2 particles and its precursors as observed during the lockdown. Before the lockdown, C2 particles were significantly originated from biomass burning emissions and their subsequent aqueous-phase oxidation. The hourly variation patterns and correlation analysis before the lockdown suggested that relative humidity (RH) and aerosol liquid water content (ALWC) played a key role in the formation of C2 particles and the increased aerosol acidity can promote the conversion of precursors such as glyoxal (Gly) and methyglyoxal (mGly) into C2 particles in the aqueous phase. RH and ALWC decreased sharply but O3 concentration and solar radiation increased remarkably during the lockdown, the O3-dominated photochemical pathways played an important role in the formation of C2 particles in which aerosol acidity was ineffective. Our study indicated that air pollution treatment sponges on a joint-control and balanced strategy for controlling numerous pollutants.
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PMID:Enhanced photochemical formation of secondary organic aerosols during the COVID-19 lockdown in Northern China. 3322 77


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