In the natural environment, interactions between species are a common natural phenomena. The mechanisms of interaction between different species are mainly studied using genomic, transcriptomic, proteomic, and metabolomic techniques. Metabolomics is a crucial part of system biology and is based on precision instrument analysis. In the last decade, the emerging field of metabolomics has received extensive attention. Metabolomics not only provides a qualitative and quantitative method for studying the mechanisms of interactions between different species, but also helps clarify the mechanisms of defense between the host and pathogen, and to explore new metabolites with various biological activities. This review focuses on the methods and progress of interspecies metabolomics. Additionally, the prospects and challenges of interspecies metabolomics are discussed.

Temperature is a key factor for determining the lifespan of both poikilotherms and homeotherms. It is believed that animals live longer at lower body temperatures. However, the precise mechanism remains largely unknown. Here, we report that autophagy serves as a boost mechanism for longevity at low temperature in the nematode Caenorhabditis elegans. The adiponectin receptor AdipoR2 homolog PAQR-2 signaling detects temperature drop and augments the biosynthesis of two ω-6 polyunsaturated fatty acids, γ-linolenic acid and arachidonic acid. These two polyunsaturated fatty acids in turn initiate autophagy in the epidermis, delaying an age-dependent decline in collagen contents, and extending the lifespan. Our findings reveal that the adiponectin receptor PAQR-2 signaling acts as a regulator linking low temperature with autophagy to extend lifespan, and suggest that such a mechanism may be evolutionally conserved among diverse organisms.