Rats Sniff Off Toxic Air

Abstract

Breathing air is a fundamental human need, yet its safety, when challenged by various harmful or lethal substances, is often not properly guarded. For example, air toxicity is currently monitored only for single or limited number of known toxicants, thus failing to fully warn against possible hazardous air. Here, we discovered that within minutes living rats emitted distinctive profiles of volatile organic compounds (VOCs) via breath when exposed to various airborne toxicants such as endotoxin, O 3 , ricin, and CO 2 . Compared to background indoor air, when exposed to ricin or endotoxin aerosols breath-borne VOC levels, especially that of carbon disulfide, were shown to decrease; while their elevated levels were observed for O 3 and CO 2 exposures. A clear contrast in breath-borne VOCs profiles of rats between different toxicant exposures was observed with a statistical significance. Differences in MicroRNA regulations such as miR-33, miR-146a and miR-155 from rats' blood samples revealed different mechanisms used by the rats in combating different air toxicant challenges. Similar to dogs, rats were found here to be able to sniff against toxic air by releasing a specific breath-borne VOC profile. The discovered science opens a new arena for online monitoring air toxicity and health effects of pollutants.

Breath-borne VOC Biomarkers for COVID-19

“…5,7 When exposed to substances, the rats were observed to shortly emit distinctive VOC profiles in a recent work. 8 Likewise, when people are infected by SARS-CoV-2, characteristic protein and metabolite changes were observed; and more than 100 lipids were reported to be down-regulated in their blood sera. 9 Here we show that breath-borne ethyl butyrate (C6H12O2) seems to be characteristic of COVID-19 and URTI (SARS-CoV-2 negative) patients (both of them represent respiratory infections) when compared with subjects with LC, HC, and HCW (Table 1).…”

Gene-Regulated Release of Distinctive Volatile Organic Compounds from Stressed Living Cells

“…cerevisiae and are thought to be produced mainly through fatty acid decarboxylation and reaction with acetyl coenzyme (acetyl-CoA). , The concentrations of but-1-ene, ethylene, acetylene, ethane, toluene, and ethylbenzene in the yeast inoculum were significantly lower than those in the SC medium, suggesting that these five VOCs were mainly from the background and could be degraded by the yeast cells. In our previous study, ethylene and ethane were also found at higher levels in the indoor air than those in the breath of rats . It has been shown that the S.…”

“…This implies that ethyl acetate probably is a common metabolite of yeast in response to external toxic stress. In our previous study, ethyl acetate was also shown to increase in the breath of rats after exposure to ricin . Acetate esters, such as ethyl acetate, isoamyl acetate, and isobutyl acetate, are common flavor metabolites in yeast that have been shown to convert from carboxylic acids by condensation with acetyl-CoA readily and potentially prevent the accumulation of these toxic acids …”

“…It was recently demonstrated that TVOC (total VOC) levels in the breath of rats were shown to change significantly within 10 min of exposure to airborne toxicants and different toxic substances resulted in characteristic exhaled VOC profiles . These changes may be related to the rats’ defense mechanisms against toxicants.…”

Study on Indoor and Outdoor Fine Particle Exposure Level, Bacterial Composition, and Diversity in a Severe Cold Region of China

“…Moreover, its negative effects increase in haze weather (Wang et al 2015). Bioaerosols also increase the risk of spreading resistance genes (Li et al 2018;Chen et al 2020). In the HVAC system, Yu et al (2019) found that yeast and Penicillium are the main species on the basement walls of residential buildings.…”