Interesting and exciting papers related to chemical ecology are getting churned out week after week. In this semi-regular segment ("relevant or not") we will concisely summarize a small selection of interesting (relevant) studies that have come out in the last couple weeks.
Sigillin A is a newly discovered natural product produced by the snow flea (Certaophysella sigillata). This little guy is a winter-active form of springtail – flightless fleas that live in the soil. Schmidt et al. show that snow fleas produce a chemical repellant (sigillin A, shown above) that deters spiders, ants, millipedes, mites, and other common snow flea predators that are abundant in the soil. This novel molecule is interesting from a chemical perspective because it contains multiple chlorine atoms - an unusual feature for a terrestrially produced natural product. Next steps for this study will undoubtedly involve determining how this molecule is synthesized by the snow flea (or more likely by a symbiotic bacteria residing on the snow flea).
This week in Cell, Liu et al. published a study on the success of a previously discovered natural product, Celastrol, in the treatment of obesity in mice. Celastrol is produced by a bad-ass plant called thunder god vine (Tripterygium wilfordii), which is used in traditional Chinese medicine for treatment of basically all diseases, syndromes, and afflictions (well, almost). In this study, researchers showed that treatment with celastrol re-sensitized diet-induced obese mice to leptin – a hormone that basically tells your central nervous system when you are satiated. Much like insulin-resistance in type 2 diabetes, certain cases of obesity can be caused by (or exacerbated by) resistance to leptin; finding a way to re-sensitize the body to this hormone could be a viable weight-loss option. While celastrol's mechanism of action is still unclear, a number of biological activities have been ascribed to this natural product (anti-inflammatory, antioxidant) as well as to the producing plant (anti-cancer, contraceptive). It's sort of interesting to contemplate how this newly exposed bioactivity of celastrol could relate to its natural function.
Two papers were recently published on the role of the mammalian hormone oxytocin and its effects on inter and intra-species bonding. Oxytocin is a peptide consisting of 9 amino acids linked together. It has long been known to be an important neuro-signaling molecule that plays a significant role in social behaviors - most notably pair-bonding (aka love and monogamy and all that).
Marlin et al. demonstrate the role of oxytocin in mediating maternal behaviors in mice by exploring the relationship between oxytocin and the tuning of a mother’s auditory perception of her pup’s distress call. In a study too complex to sum up adequately, researchers demonstrate that oxytocin signaling may facilitate learning in new mothers. Read a nice summary here.
Nagasawa et al. explore how oxytocin signaling may indicate co-evolution in inter-species interactions through bonding between humans and their pets. Experiments conducted in this paper literally involve dog and human gazing into each other's eyes for prolonged periods of time. Ultimately these researchers demonstrate that oxytocin mediates bonding between a pet and its owner much in the same way that it mediates bonding between individuals of the same species. Nagasawa et al. also explore whether the role of oxytocin in dog-human bonding is reflected in wolves, providing some food for thought on the evolutionary implications of domestication.