Noninvasive Detection of Chemical Defenses in Poison Frogs Using the MasSpec Pen

Abstract

Poison frogs are well-known for their fascinating ability to store alkaloids in their skin as chemical defense against predators. Chemical methods used to study these alkaloids are limited by requirements for euthanasia or stress during sampling. Here, we demonstrate sensitive and biocompatible alkaloid detection and monitoring in vivo using the MasSpec Pen, a handheld, noninvasive chemical detection device coupled to a mass spectrometer. The MasSpec Pen allowed rapid (<15 s), gentle, and consecutive molecular analysis without harm or undue stress to the animals. Through a month-long alkaloid-feeding study with the dyeing poison frog, we observed temporal dynamics of chemical sequestration in vivo by comparing frogs fed the alkaloid decahydroquinoline (DHQ) to vehicle-fed frogs. We also demonstrate the feasibility of the MasSpec Pen for the untargeted detection of rich alkaloid profiles from skin extracts of the Diablito poison frog, collected from two distinct geographical populations in Ecuador. The results obtained in this study demonstrate the utility of the MasSpec Pen for direct, rapid, and biocompatible analysis of poison frog alkaloids.

Applications of ambient ionization mass spectrometry in 2022: An annual review

“…Finally, the ability of AIMS to achieve non‐proximate sampling enables the possibility of analyzing whole organisms. AIMS has been demonstrated in the analysis of live bacterial colonies for several years, however, more recent studies have applied ambient ionization techniques to the direct analysis of much larger species, including mosquito larvae 146 and even living frogs 147 . The ability to perform in situ non‐destructive analysis offers the exciting potential to study the real‐time chemistry of living organisms and gain a fascinating insight into animal biology.…”

“…Kriger et al used the MasSpec Pen, a device traditionally utilized for clinical diagnostics, for the analysis of poison frogs. 147 Poison frogs harness the ability to excrete different alkaloids as a chemical defence against predators. By applying the MasSpec Pen directly to the skin of the live frog, the authors achieved the measurement of target alkaloids throughout a month-long feeding study, in addition to performing untargeted analysis of skin excretions.…”

“…Kriger et al. used the MasSpec Pen, a device traditionally utilized for clinical diagnostics, for the analysis of poison frogs 147 . Poison frogs harness the ability to excrete different alkaloids as a chemical defence against predators.…”

Data Acquisition and Intraoperative Tissue Analysis on a Mobile, Battery-Operated, Orbitrap Mass Spectrometer

“…The high temperature (350 °C) and reduced pressure (2 mbar) within the vacuum sealed manifold facilitates desolvation and formation of gas-phase ions for immediate MS analysis. The MSPen has been applied for the direct analysis of samples in clinical ,− and nonclinical research studies − coupled to ion trap, Orbitrap, and time-of-flight mass spectrometers. In intraoperative studies, − we have exclusively implemented the MSPen coupled to Orbitrap mass spectrometers to analyze human tissues including thyroid, parathyroid, pancreas, breast, and ovarian either in vivo or ex vivo immediately after surgical excision.…”

Non-proximate Sampling and Photoionization for Damage-Free Mass Spectrometric Analysis of Intact Native American Baskets

“…The desorption/ionization source, sample surface, and mass spectrometer (MS) inlet are typically within centimeters or less of each other. Rare or precious objects, living specimens, and works of art, however, must remain whole and undamaged instead of being cut to pieces to accommodate sampling and instrumentation. Some inanimate objects may have previously self-sampled, shedding fragments of their own accord as a result of age or fragility, but the fragments may not have fallen conveniently from an area of interest.…”