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Douka, K.

Publications and source records attributed to Douka, K..

3 recordsLinked to original sources

A candidate electromagnetic channel for coordination between physicallyseparated Drosophila

While filming Drosophila melanogaster recovering together from xenon anesthesia, we noticed frequent synchronous pauses in flies recovering in the same chamber. To ask whether such coordination could survive physical separation of the animals, we housed flies individually in the opaque wells of a multi-well plate, with no visual or tactile contact. They still coordinated the magnitude of their movements around a shared light*dark startle more closely than the shared stimulus alone can explain. We isolate this excess coordination with a measure that subtracts the stimulus-driven component by comparing movements within versus across transitions. A complementary common-mode statistic shows that flies also remain weakly but reproducibly correlated away from the transitions. The tested conventional channels do not readily account for the effect: vision is excluded by the opaque walls, and self-generated substrate vibration is disfavored for the background common mode because coordination does not scale with movement amplitude and persists when the continuous side-wall path between wells is interrupted by air gaps. The transition signal declined across the material series from plastic toward aluminum. This paNern is not a simple metal-versus-nonmetal split. It is consistent with material-dependent near-field magnetic radiofrequency coupling through the well geometry and transparent imaging aperture. Vector-network measurements also indicate that near-field inter- well coupling differs between steel and aluminum. We have previously shown that Drosophila emit spontaneous, metabolically powered magnetic radiofrequency radiation that tracks nervous-system activity. Together these results are consistent with a near-field magnetic emission that can leak between separated individuals. We discuss radical-pair detection, possible emission mechanisms, and experiments needed to identify the carrier frequency, detector, and biological role. SignificanceFruit flies housed in separate, opaque chambers that block sight and touch nonetheless coordinate their movements. The coordination persists when mechanical vibration paths between chambers are cut. The coordination is absent when the plate is made of aluminum, and intermediate in size when the plate is made of ferromagnetic steel. This ordering, together with direct RF-coupling measurements, points to a near-field magnetic radiofrequency signal passing between individuals, though the carrier frequency and detector remain unknown. Because flies are already known to emit faint, metabolically powered radiofrequency fields that track nervous-system activity, these results raise the possibility that nervous systems both emit and detect such fields. If confirmed, this would identify an unrecognized magnetic radiofrequency channel in animal biology and suggest that brains are less electromagnetically private than assumed.

neuroscience↗

Non-destructive radiocarbon dating of bone

Since the 1950s, radiocarbon measurements have anchored archaeological chronologies dating back to 50,000 years, with bone collagen being a commonly dated material. Despite advances in collagen extraction protocols, the process remains destructive, requiring sampling by sawing, drilling or crushing of dry bone, that can damage or destroy physical features and archaeological evidence, and often consumes the entire specimen. While non-destructive approaches have recently been applied in ancient genomics and palaeoproteomics, no equivalent approach has been established for radiocarbon dating of bone. Here, we outline a non-destructive collagen extraction workflow that avoids invasive sampling (cutting or drilling) and produces no visible damage to the bone. By heating the bone in hot water for several hours, collagen is solubilized, and the resulting collagenous solution can be purified and AMS dated. Here we show that the amino acid composition, C/N atomic ratios, {delta}13C and {delta}15N values of the hot-water-extracted collagen are comparable to collagen isolated from the same bones using classic decalcification methodologies. The hot water extraction method was tested on various bones, ranging from the Bronze Age to the Middle and Upper Paleolithic periods, which had been dated previously using routine destructive methods that involved acid demineralization. Our results show that non-destructive collagen extraction, coupled with an additional purification step e.g., ultrafiltration, yields identical radiocarbon ages to those obtained via the routine destructive methods.

paleontology↗

LncRNAs interacting with the translation machinery contribute to human neuronal differentiation.

LncRNAs are less conserved, yet more tissue and developmental-stage specific than mRNAs and are particularly enriched in the nervous system of Drosophila melanogaster, mouse and human. The function of cytoplasmic lncRNAs and their potential translation remains poorly understood. Here we performed Poly-Ribo-Seq to understand the interaction of lncRNAs with the translation machinery and the functional consequences during neuronal differentiation of SH-SH5Y cells. We discovered 237 cytoplasmic lncRNAs upregulated during early neuronal differentiation, most of which are associated with polysome complexes. The majority are cytoplasmically enriched and are intergenic or anti-sense. In addition, we find 45 small ORFs in lncRNAs to be actively translated, 17 specifically upon differentiation. 11 of these smORFs exhibit high sequence conservation across Hominidae suggesting they are under strong selective constraint with putative function in this clade. We discover LINC01116 is induced upon differentiation and contains an 87 codon smORF, which we detect as translated, with increased ribosome profiling signal upon differentiation. The LINC01116 peptide exhibits a cytoplasmic distribution and is detected in neurites. Knockdown of LINC01116 results in significant reduction of neurite length in differentiated cells indicating it contributes to neuronal differentiation. Our findings indicate lncRNAs are a source of non-canonical peptides and contribute to neuronal function.

molecular biology↗