Schofield, A. | bioRxiv Science

bioRxiv2026

A Charge Detection Mass Spectrometer for the Analysis of Megadalton-sized Molecules

Advances in Electrostatic Linear Ion Trap (ELIT) Charge Detection Mass Spectrometry (CDMS) over the past 10 years have revolutionized its use for analyzing very high-molecular-weight species such as protein complexes, viral vectors, vaccines, viruses, and amyloid fibrils. Nonetheless, ELIT-based CDMS has remained confined to a small number of specialized instrumentation groups, predominantly in academia, where large and complex home-built instruments are operated by highly skilled scientists in dedicated facilities. In this report, we discuss the primary challenges addressed in the design of a benchtop ELIT-based CDMS instrument. We highlight key design aspects of the hardware, acquisition modes, and control software, and we present important performance metrics (mass range, resolution, and sensitivity) demonstrated using samples representative of the technologys key application areas.

biophysics↗

bioRxiv2023

Vitamin B12 conveys a protective advantage to phycosphere-associated bacteria at high temperatures

Many marine microbes require vitamin B12 (cobalamin) but are unable to synthesize it, necessitating reliance on other B12-producing microbes. Thus, phytoplankton and bacterioplankton community dynamics can partially depend on the production and release of a limiting resource by members of the same community. We tested the impact of temperature and B12 availability on the growth of two bacterial taxa commonly associated with phytoplankton: Ruegeria pomeroyi, which produces B12 and fulfills the B12 requirements of some phytoplankton, and Alteromonas macleodii, which does not produce B12 but also does not strictly require it for growth. For B12-producing R. pomeroyi, we further tested how temperature influences B12 production and release. Access to B12 significantly increased growth rates of both species at the highest temperatures tested (38{o}C for R. pomeroyi, 40{o}C for A. macleodii) and A. macleodii biomass was significantly reduced when grown at high temperatures without B12, indicating that B12 is protective at high temperatures. Moreover, R. pomeroyi produced more B12 at warmer temperatures but did not release detectable amounts of B12 at any temperature tested. Results imply that increasing temperatures and more frequent marine heatwaves with climate change will influence microbial B12 dynamics and could interrupt symbiotic resource sharing.

microbiology↗