Biology subjects

McKeown, J.

Publications and source records attributed to McKeown, J..

3 recordsLinked to original sources

bioRxiv2025

Megabarcoding dark taxa - Assessing the utility of mass DNA barcoding for phorid fly species discovery

Many hyperdiverse, small-bodied insect families contain numerous undescribed species, generally termed "dark taxa". Scuttle flies (Diptera: Phoridae), being among the most diverse insect groups globally, are a prime example. DNA barcoding can help delineating dark taxa, particularly when integrated with morphology, and/or additional molecular evidence. We sequenced COI-barcodes from 9,120 Finnish phorid specimens and initially identified them using BOLD database. Furthermore, species identifications of all 843 non-Megaselia specimens were confirmed morphologically. Initially, the BOLD-based identifications matched the morphological identifications only in 68% of the cases, which resulted from many misidentifications in BOLD. After adjusting the BOLD reference identifications based on morphological analyses of male features, we established a reliable framework for female identification. This is advantageous for future identification of females, as they are often excluded from traditional identification keys. Only two species was discovered as new to Finland, demonstrating that Finnish non-Megaselia fauna is well-known. Although DNA barcodes show great promise for identifying phorids, incorrectly identified reference sequences remain challenging, not the functionality of COI itself. The number of Megaselia BINs greatly exceeded the known Finnish species count, with many sequences lacking matches in BOLD. This further highlights Megaselia as a particularly dark group, for which genetic tools are essential for uncovering species identities and assessing diversity.

zoology↗

bioRxiv2019

Novel regulation from novel interactions: Identification of an RNA sponge that controls the levels, processing and efficacy of the RoxS riboregulator of central metabolism in Bacillus subtilis

Small RNAs (sRNAs) are a taxonomically-restricted but transcriptomically-abundant class of post-transcriptional regulators. While potentially of importance, we know the function of few. This is in no small part because we lack global-scale methodology enabling target identification, this being especially acute in species without known RNA meeting point proteins (e.g. Hfq). We apply a combination of psoralen RNA cross-linking and Illumina-sequencing to identify RNA-RNA interacting pairs in vivo in Bacillus subtilis, resolving previously well-described interactants. Although sRNA-sRNA pairings are rare (compared with sRNA/mRNA), we identify a robust example involving the unusually conserved sRNA (RoxS/RsaE) and an unstudied sRNA that we term Regulator of small RNA A (RosA). This interaction is found in independent samples across multiple conditions. Given the possibility of a novel associated regulatory mechanism, and the rarity of well-characterised bacterial sRNA-sRNA interactions, we mechanistically dissect RosA and its interactants. RosA we show to be a sponge RNA, the first to be described in a Gram-positive bacterium. RosA interacts with at least two sRNAs, RoxS and FsrA. Unexpectedly, it acts differently on each. As expected of a sponge RNA, FsrA is sequestered by RosA. The RosA/RoxS interaction is more complex affecting not only the level of RoxS but also its processing and efficacy. Importantly, RosA provides the condition-dependent intermediary between CcpA, the key regulator of carbon metabolism, and RoxS. This not only provides evidence for a novel, and functionally important, regulatory mechanism, but in addition, provides the missing link between transcriptional and post-transcriptional regulation of central metabolism.

microbiology↗

bioRxiv2016

Modulation of Body Mass Composition using Vestibular Nerve Stimulation.

There is increasing evidence of a \"set-point\" for body weight in the brain, that is regulated by the hypothalamus. This system modifies feeding behavior and metabolic rate, to keep body fat within predetermined parameters. It is also known that animals subjected to chronic centrifugation show a reduction in body fat. Experiments with mutant mice found that this loss of fat appears to be mediated by a vestibulo-hypothalamic pathway. Vestibular nerve stimulation (VeNS), also known as galvanic vestibular stimulation, involves non-invasively stimulating the vestibular system by applying a small electrical current between two electrodes placed over the mastoid processes. We suggest that any means of repeatedly stimulating the otolith organs in humans would cause a reduction in total body fat, and that VeNS would be a useful technique to use in this regard. Below we provide pilot data to support this idea.

neuroscience↗