Biology subjects

Thomas, C. D.

Publications and source records attributed to Thomas, C. D..

3 recordsLinked to original sources

bioRxiv2021

A millennium of increasing ecosystem diversity until the mid-20th century

Land-use change is widely regarded as a simplifying and homogenising force in nature. In contrast, analysing global land-use reconstructions from the 10th to 20th centuries, we found progressive increases in the number, evenness, and diversity of ecosystems (including human-modified land-use types) across the globe. Ecosystem diversity increased more rapidly after [~]1700CE, then slowed or partially reversed (depending on the metric) following the mid-20th century acceleration of human impacts. Differentiation also generally increased across space, with homogenization only evident in the presence-absence analysis of ecosystem types at the global scale. Our results suggest that human land-use changes have primarily driven increases in ecosystem diversity over the last millennium.

ecology↗

bioRxiv2020

Structure-guided point mutations on FusionRed produce a brighter red fluorescent protein

The development of fluorescent proteins (FPs) has revolutionized biological imaging. FusionRed, a monomeric red FP (RFP), is known for its low cytotoxicity and appropriate localization of target fusion proteins in mammalian cells but is limited in application by low fluorescence brightness. We report a brighter variant of FusionRed, FusionRed-MQV, which exhibits an extended fluorescence lifetime (2.8 ns), enhanced quantum yield (0.53), higher extinction coefficient (~140,000 M-1cm-1), increased radiative rate constant and reduced non-radiative rate constant with respect to its precursor. The properties of FusionRed-MQV derive from three mutations - M42Q, C159V and the previously identified L175M. A structure-guided approach was used to identify and mutate candidate residues around the phenol and the acylimine ends of the chromophore. The C159V mutation was identified via lifetime-based flow cytometry screening of a library in which multiple residues adjacent to the phenol end of the chromophore were mutated. The M42Q mutation is located near the acylimine end of the chromophore and was discovered using site-directed mutagenesis guided by x-ray crystal structures. FusionRed-MQV exhibits 3.4-fold higher molecular brightness and a 5-fold increase in the cellular brightness in HeLa cells (based on FACS) compared to FusionRed. It also retains the low cytotoxicity and high-fidelity localization of FusionRed, as demonstrated through assays in mammalian cells.

biophysics↗

bioRxiv2019

Unlocking the potential of historical abundance datasets to study biomass change in flying insects

O_LITrends in insect abundance are well-established in some datasets, but far less is known about how abundance measures translate into biomass trends. Moths (Lepidoptera) provide particularly good opportunities to study trends and drivers of biomass change at large spatial and temporal scales, given the existence of long-term abundance datasets. However, data on the body masses of moths are required for these analyses, but such data do not currently exist. C_LIO_LITo address this data gap, we collected empirical data in 2018 on the forewing length and dry mass of field-sampled moths, and used these to train and test a statistical model that predicts the body mass of moth species from their forewing lengths (with refined parameters for Crambidae, Erebidae, Geometridae and Noctuidae). C_LIO_LIModelled biomass was positively correlated, with high explanatory power, with measured biomass of moth species (R2 = 0.886 {+/-} 0.0006, across 10,000 bootstrapped replicates) and of mixed-species samples of moths (R2 = 0.873 {+/-} 0.0003), showing that it is possible to predict biomass to an informative level of accuracy, and prediction error was smaller with larger sample sizes. C_LIO_LIOur model allows biomass to be estimated for historical moth abundance datasets, and so our approach will create opportunities to investigate trends and drivers of insect biomass change over long timescales and broad geographic regions. C_LI

ecology↗