Biology subjects

Waterfall, M.

Publications and source records attributed to Waterfall, M..

3 recordsLinked to original sources

bioRxiv2026

A Genome-Wide Genetic Screen Identifies a Novel kDNA Replication Protein in Trypanosomes

Mitochondrial DNA of trypanosomatid parasites is organized into a topologically complex structure, named kinetoplast (kDNA). Replication, segregation and expression of kDNA involve an estimated [~]300 proteins, only a fraction of which have been identified and characterized. Here, we report the development of a genetic screen in Trypanosoma brucei to identify novel kDNA maintenance factors. Of the 20 highest-ranked genes identified, six are known kDNA maintenance factors. We selected one hit, Tb927.8.4240, a gene of previously unknown function, for experimental follow-up. Ultrastructure expansion microscopy using a tagged version of the protein reveals a dynamic localization during the cell cycle. RNAi-mediated ablation of Tb927.8.4240 results in the progressive but incomplete loss of kDNA, with only a minor effect on the tripartite attachment complex, suggesting the protein is involved in kDNA replication but not segregation. The growth phenotype of Tb927.8.4240 ablation is fully rescued in a kDNA-independent genetic background, confirming a specific role in kDNA replication. In summary, we describe a functional genetic screen for the identification of kDNA maintenance factors in trypanosomes, validate one hit as a novel kDNA replication factor, and provide a prioritized hit list as a promising starting point for the future identification of additional factors.

molecular biology↗

bioRxiv2024

Testing microbial biomining from asteroidal material onboard the International Space Station

Expanding human space exploration beyond Earths orbit necessitates efficient technologies for self-sustainable acquisition of local resources to overcome unviable resupply missions from Earth. Potential source of materials are asteroids, some of which contain valuable metals, such as platinum group elements. The BioAsteroid experiment, performed onboard the International Space Station, tested the use of microorganisms (bacteria and fungi) to carry out mining of useful elements from asteroidal material (L-chondrite) under microgravity, in support of a long-term human presence in space. The fungus Penicillium simplicissimum, enhanced the mean release of palladium, platinum and other elements from the meteorite material in microgravity, compared to non-biological leaching. However, there was large variability in the results. For many elements, non-biological leaching under microgravity was enhanced compared to terrestrial gravity, while bioleaching was unaffected. Metabolomics results revealed clear patterns that highlight the influence of space conditions on the microbial metabolism, particularly for P. simplicissimum. We identified the presence of carboxylic acids, and molecules of potential biomining and pharmaceutical interest, enhanced in microgravity. These results show a non-trivial effect of microgravity on bioleaching, highlighting the requirement of an optimal combination of microorganism(s), rock substrate, and conditions for successful biomining, both in space and Earth.

microbiology↗

bioRxiv2019

The determinants of genetic diversity in butterflies - Lewontin's paradox revisited

Under the neutral theory genetic diversity is expected to be a simple function of population size. However, comparative studies have consistently failed to find any strong correlation between measures of census population size and genetic diversity. Instead, a recent comparative study across several animal phyla identified propagule size as the strongest predictor of genetic diversity, suggesting that r-strategists that produce many offspring but invest little in each, have greater long-term effective population sizes. We present a comparison of genome-wide levels of genetic diversity across 38 species of European butterflies (Papilionoidea). We show that across butterflies, genetic diversity varies over an order of magnitude and that this variation cannot be explained by differences in abundance, fecundity, host plant use or geographic range. Instead, we find that genetic diversity is negatively correlated with body size and positively with the length of the genetic map. This suggests that variation in genetic diversity is determined both by fluctuation in Ne and the effect of selection on linked neutral sites.

evolutionary biology↗