Environmental RNA Reveals Heat Stress in Water Fleas

Recommendable! Due to the global Covid-19 pandemic, we are now more familiar with mRNA! Ready for eRNA? 😊 

Notice from the abstract that these scientists are ideologues! In the first sentence of the abstract they reflexively regurgitate two demagogueries of our time! Plus, they mandate to safeguard by whom (Big Government)? Scientists are all to human!

"... But until recently, researchers lacked the tools needed to make use of that information, which comes in the form of environmental DNA (eDNA) or environmental RNA (eRNA). While scientists have begun to explore uses for eDNA in recent years, fewer have tackled its fickler, more elusive sister eRNA. Now, a team of researchers ... have used eRNA to identify signs of heat stress in water fleas ...

It’s one of the first studies to use eRNA to make inferences about organism health ..."

I briefly looked at the current version (v2) of the PDF file of this study, even for a preprint it appears to be in a rather crude state almost like a draft 

From the abstract:

"To safeguard biodiversity in a changing climate [????], we require taxonomic information about species turnover and insights into the health of organisms. Environmental DNA approaches are increasingly used for species identification, but cannot provide functional insights. Transcriptomic methods reveal the physiological states of macroorganisms, but are currently species specific and require tissue sampling or animal sacrifice, making community-wide assessments challenging. Here, we test if broad functional information (expression level of the transcribed genes) can be harnessed from environmental RNA (eRNA), which includes extra-organismal RNA from macroorganisms [humans are macroorganisms too, I suppose] along with whole microorganisms. We exposed Daphnia pulex as well as phytoplankton prey and microorganism colonizers to control (20 °C) and heat stress (28 °C) conditions for seven days. We sequenced eRNA from tank water (after complete removal of Daphnia) as well as RNA from Daphnia tissue, enabling comparisons of extra-organismal and organismal RNA based gene expression profiles. Both RNA types detected similar heat stress responses of Daphnia. Using eRNA, we identified 32 Daphnia genes to be differentially expressed following heat stress. Of these, 17 were also differentially expressed and exhibited similar levels of relative expression in organismal RNA. In addition to the extra-organismal Daphnia response, eRNA detected community-wide heat stress responses consisting of distinct functional profiles and 121 differentially expressed genes across 8 taxa. Our study demonstrates that environmental transcriptomics based on eRNA can non-invasively reveal gene expression responses of macroorganisms following environmental changes, with broad potential implications for the biomonitoring of ecological health across the trophic chain."

Environmental RNA Reveals Heat Stress in Water Fleas | The Scientist Magazine® The eRNA detection method could one day be used to catch early warning signs of distress in wild ecosystems. 

Environmental transcriptomics under heat stress: Can environmental RNA reveal changes in gene expression of aquatic organisms? (open access, preprint)