Biology subjects

Adair, J.

Publications and source records attributed to Adair, J..

4 recordsLinked to original sources

bioRxiv2025

A meta-analysis of periodic and aperiodic M/EEG components in Parkinson's disease

Parkinsons disease is characterised by a range of motor and non-motor changes that can negatively impact quality of life. Many studies have identified potential clinical electrophysiological biomarkers of Parkinsons disease with an aim of developing new methods of identifying at-risk patients, and to form the basis of therapeutic interventions. However, these studies do not present consistent results, and a formal meta-analysis is warranted to identify reliable M/EEG characteristics across datasets. In this meta-(re-)analysis of open-access M/EEG datasets (n = 6; 4 EEG and 2 MEG), we compared periodic and aperiodic characteristics of resting-state recordings in 368 patients with Parkinsons disease and 570 age-matched healthy controls. Specifically, we compared the power and peak frequency of the aperiodic-adjusted alpha and beta oscillations, and the aperiodic exponent and offset across the two groups. Using spectral parametrisation, individuals with Parkinsons disease had higher alpha-band power and a slower alpha peak frequency compared to controls, however no group differences in beta-band power and peak frequency were identified in this resting state data. Parkinsons patients were furthermore found to have consistently higher aperiodic offset and exponent, possibly indicative of increased cortical inhibition. In conclusion, this large cohort meta-analysis points to a broadly consistent pattern of both periodic and aperiodic changes in Parkinsons patients in M/EEG signal that may be used to develop diagnostics and targeted interventions in the future.

neuroscience↗

bioRxiv2024

Cross-species Comparison of Ultramafic Rock Bio-accelerated Weathering Performance

Carbon mineralization is a natural process that sequesters atmospheric CO2 by reacting it with cations (e.g., Mg2+, Ca2+) released by weathering of rocks to form solid carbonates. However, this process is too slow to capture the excess CO2 resulting from anthropogenic emissions in time to prevent significant warming of the atmosphere1-3. Additionally, accelerating carbon mineralization process by chemical or mechanical methods has proven prohibitively expensive to date4. Microbial rock-dissolution processes, including acidolysis, redoxolysis, and complexolysis, have the potential to accelerate weathering with low energy input5. However, there is no industrially useful microbe capable of dissolving ultramafic (rich in ferromagnesian minerals) rocks, suggesting that one will need to be discovered or built with synthetic biology. While microbes are known to dissolve ultramafic minerals6,7, the performance envelopes for these processes remain uncharacterized, and significant gaps exist in our knowledge of microbe-mineral interaction processes. Here, we make a normalized performance comparison of the dissolution of the ultramafic rock dunite (> 90% olivine ((Mg, Fe)2SiO4)) by three well-known mineral-dissolving microbes: Gluconobacter oxydans7-9, Sphingomonas desiccabilis10,11, and Penicillium simplicissimum12-14. We show that G. oxydans outperformed P. simplicissimum and S. desiccabilis, producing the most acidic biolixiviant (pH 2.15 when leaching 1% pulp density), and extracting the most magnesium (3,130 mg/L when leaching at 3% pulp density). Additionally, G. oxydans co-dissolves nine other metals, eight of which are critical for energy technologies (Cr, Mn, Co, Ni, Cu, and Zn)15,16 with a maximum dissolved concentration of 33 mg/L for Ni. While increasing the pulp density of the dunite (solid to liquid ratio) resulted in higher metal dissolution by G. oxydans and S. desiccabilis, notably pulp densities above 2% inhibited mineral dissolution by P. simplicissimum. Our results provide evidence that the gap in performance between G. oxydans and the other two microbes increases with pulp density, and thus, G. oxydans is best suited for process and genetic engineering to maximize performance and minimize costs and environmental impacts of bio-accelerated weathering. Finally, we propose that G. oxydans and P. simplicissimum can use cellulosic hydrolysate as a cost-effective substitute for glucose for biolixiviant production.

bioengineering↗

bioRxiv2023

Constraints on Lanthanide Separation by Selective Biosorption

Rare Earth Elements (REE) are essential ingredients of sustainable energy technologies1-5, but separation of lanthanides is considered one of the hardest problems in chemistry today6. Biosorption, where molecules adsorb to the surface of biological materials, offers a sustainable alternative to environmentally harmful solvent extractions currently used for REE separations. The REE-biosorption capabilities of some microorganisms already allow for REE separations that under specialized conditions are competitive with solvent extractions7. Our recent work has discovered the genetic basis for REE biosorption selectivity8. However, it is unclear if the small changes to selectivity produced by changes to single genetic loci could allow biosorption to leapfrog existing REE separation technologies. In this article we present three models of lanthanide separation by biosorption and desorption. The first model shows that if a biosorbing microbe behaves as it if has a single type of binding site with small preference for one lanthanide, then the small changes in selectivity produced by changes to a single genetic locus could reduce the length of a separation process by {approx} 25%. Large multi-locus gene edits could reduce a separation process length by almost 90%. On the other hand, if the microbe contains multiple sites each with a distinct preference for an individual lanthanide, then separations become challenging and larger genetic edits would be needed to enable high purity. However, even if these large genetic edits are not possible, high purity separations could still be possible by combining multiple microbes, each with small increases in selectivity, with the first designed to enrich for the target lanthanide, while subsequent microbes are designed to remove contaminants.

synthetic biology↗

bioRxiv2021

Enzyme Aggregation and Fragmentation Induced by Catalysis Relevant Species

It is usually assumed that enzymes retain their native structure during catalysis. However, the aggregation and fragmentation of proteins can be difficult to detect and sometimes conclusions are drawn based on the assumption that the protein is in its native form. We have examined three model enzymes, alkaline phosphatase (AkP), hexokinase (HK) and glucose oxidase (GOx). We find that these enzymes aggregate or fragment after addition of chemical species directly related to their catalysis. We used several independent techniques to study this behavior. Specifically, we found that glucose oxidase and hexokinase fragment in the presence of D-Glucose but not L-glucose, while hexokinase aggregates in the presence of Mg2+ ion and either ATP or ADP at low pH. Alkaline phosphatase aggregates in the presence of Zn2+ ion and inorganic phosphate. The aggregation of hexokinase and alkaline phosphatase does not appear to attenuate their catalytic activity. Our study indicates that specific multimeric structures of native enzymes may not be retained during catalysis and suggests pathways for different enzymes to associate or separate over the course of substrate turnover.

biophysics↗