What’s New in Mass Spec?

The stained Centaur. A stained Centaur marble head that was once decorating the metopes of the Parthenon has now become a puzzle not only for archaeologists, but also for a research team from the University of Southern Denmark. The origin of a thin brown film that covers the artifact has confused experts; was it formed by algae and bacteria or is it the remains of a protective paint the ancient Greeks used? To determine the chemical composition of the stain, the team threw everything at the mysterious film – including LA-ICP-MS, SEM-EDX, µXRD, GC-MS, LC-MS/MS, and optical microscopy – and discovered two distinct layers. The analysis also revealed that the brown stain is composed of proteins from plants, humans, other mammals, including an egg yolk – believed to be a paint binding agent – and animal collagens. "This could suggest that someone applied paint or a conservation treatment, but since we haven't found traces of such substances, the brown color remains a mystery," said corresponding author Kaare Lund Rasmussen in a press release.

Find the kinase. Kinases are promising diagnostic and therapeutic targets for cancer, but quantifying them in human biopsies can be challenging with current methods, such as immunohistochemistry. So, researchers from the Baylor College of Medicine set out to find an alternative – combining mass spectrometry-based proteomics with their newly developed kinase inhibitor pulldown assay (KiP). The optimized methodology enabled accurate and simultaneous measurement of a 100-strong panel of target kinases. “This paper emphasizes that new methods in protein mass spectrometry hold great promise for better definition of the individual druggable landscape present in each cancer and should be more widely used for research and, ultimately, clinical care,” said corresponding author Matthew Ellis in a press release.

Bone of contention. In early 2023, skeletal remains were found in a ditch by a country road – leading researchers down a tangled path in an attempt to discover the identity of the unfortunate soul and what befell them. The “who” part of this skeleton mystery was recently unraveled by a team of researchers from across France; anthropological examination determined the victim was female over the age of 60 with time of death correlating from three months to a year before research commenced. Meanwhile, DNA analysis provided a match with a 60-year-old woman found on the Missing Persons Index. But how did she die? Hypothesizing a drug-related death, researchers conducted analysis of hair samples using targeted and untargeted liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), detecting oxazepam (361 pg/mg), nordiazepam (54 pg/mg), and alimemazine (5 pg/mg). Unfortunately, concrete answers were not forthcoming. “The interpretation of these concentrations is extremely difficult due to the risk of degradation of the hair cuticle during prolonged stay in the soil, as well as of contamination by putrefactive fluids.”

Polluting Pollination. Pollination is largely affected – and possibly disrupted – by nighttime pollution, as researchers from the University of Washington recently discovered. Specifically, the team studied the interactions between moths – the main nocturnal pollinators – and the Oenothera pallida wildflower, using mass spectrometry. The findings revealed that nitrate radicals in the atmosphere react with the flower’s pollination signaling scent, nearly eliminating it. “Our approach could serve as a roadmap for others to investigate how pollutants impact plant-pollinator interactions, and to really get at the underlying mechanisms,” said co-author Joel Thornton in a press release.