Biology subjects

Huda, A.

Publications and source records attributed to Huda, A..

5 recordsLinked to original sources

bioRxiv2021

Responses to Temperatures of Different Drosophila Species

Temperature is a critical environmental variable that affects the distribution, survival, and reproduction of most animals. Although temperature receptors have been identified in different animals, how these receptors respond to temperatures is largely unknown. Here we use modified single-fly thermotactic assays to analyze movements and temperature preferences of nine Drosophila species. The ability/inclination to move varies among these species and at different temperatures. Importantly, different species prefer various ranges of temperatures. While wild-type D. melanogaster flies avoid the warm temperature in the warm avoidance assay and the cool temperature in the cool avoidance assay, D. bipectinata and D. yakuba avoid neither warm nor cool temperatures and D. biarmipes and D. mojavensis do not avoid the warm temperature in the warm avoidance assay. These results demonstrate that Drosophila species have different mobilities and temperature preferences, thereby benefiting the research on molecular mechanisms of temperature responsiveness. Summary statementThe ability to move and the preference for temperatures vary among fly species when flies are exposed to steep temperature gradients.

animal behavior and cognition↗

bioRxiv2021

Using TrackMate to Analyze Drosophila Larval and Adult Locomotion

Drosophila adult and larvae exhibit sophisticated behaviors that are widely used in development, synaptic transmission, sensory physiology, and learning and memory research. Many of these behaviors depend on locomotion, the ability of an animal to move. However, the statistical analysis of locomotion is not trivial. Here we use an open-source Fiji plugin TrackMate to track the locomotion of Drosophila adults and larvae. We build optimal experimental setups to rapidly process recordings by Fiji and analyze by TrackMate. We also provide tips for analyzing non-optimal recordings. TrackMate extracts the X and Y positions of an animal on each frame of an image sequence or a video. This information allows for generating moving trajectories, calculating moving distances, and determining preference indices in two-choice assays. Notably, this free-cost analysis method does not require programming skills. Summary statementThis study uses an open-source Fiji plugin TrackMate to computationally analyze Drosophila adult and larval behavioral assays, which does not require programming skills.

animal behavior and cognition↗

bioRxiv2021

Gut bacteria regulate the pathogenesis of Huntington's disease in Drosophila

Changes in the composition of gut microbiota are implicated in the pathogenesis of several neurodegenerative disorders. Here, we investigated whether gut bacteria affect the progression of Huntingtons disease (HD) in transgenic Drosophila melanogaster (fruit fly) models expressing human full-length or N-terminal fragments of mutant huntingtin (HTT) protein, here referred to as HD flies. We find that elimination of commensal gut bacteria by antibiotics reduces the aggregation of amyloidogenic N-terminal fragments of HTT and delays the development of motor defects. Conversely, colonization of HD flies with Escherichia coli (E. coli), a known pathobiont of human gut with links to neurodegeneration, accelerates HTT aggregation, aggravates immobility and shortens lifespan. Similar to antibiotics, treatment of HD flies with small compounds such as luteolin, a flavone, or crocin a beta-carotenoid, ameliorates disease phenotypes and promotes survival. Crocin prevents colonization of E. coli in the gut and alters the abundance of commensal bacteria, which may be linked to its protective effects. The opposing effects of E. coli and crocin on HTT aggregation, motor defects and survival in transgenic Drosophila models support the involvement of gut-brain networks in the pathogenesis of HD.

neuroscience↗

bioRxiv2020

Telomere damage induces internal loops that generate telomeric circles

Extrachromosomal telomeric circles are commonly invoked as important players in telomere maintenance, but their origin has remained elusive. Using electron microscopy analysis on purified telomeres we show that, apart from known structures, telomeric repeats accumulate internal loops (i-loops), that occur in proximity of nicks and single-stranded DNA gaps. I-loops are induced by single-stranded damage at normal telomeres and represent the majority of telomeric structures detected in ALT (Alternative Lengthening of Telomeres) tumor cells. Our data indicate that i-loops form as a consequence of the exposure of single-stranded DNA at telomeric repeats. Finally, we show that these damage-induced i-loops can be excised to generate extrachromosomal telomeric circles resulting in loss of telomeric repeats. Our results identify damage-induced i-loops as a new intermediate in telomere metabolism and reveal a simple mechanism that links telomere damage with the accumulation of extrachromosomal telomeric circles and telomere erosion.

molecular biology↗

bioRxiv2017

Drosophila have distinct activity-gated pathways that mediate attraction and aversion to CO2

Carbon dioxide is a volatile and broad signal of many organic processes, and serves as a convenient cue for insects in search of blood hosts1-6, flowers7, decaying matter8-11, communal nests12, fruit13, and wildfires14. Curiously, although Drosophila melanogaster feed on yeast that produce CO2 and ethanol during fermentation, laboratory experiments suggest that flies actively avoid CO215-25. Here, we resolve this paradox by showing that both flying and walking fruit flies do actually find CO2 attractive, but only when they are in an active state associated with foraging. Aversion at low activity levels may be an adaptation to avoid CO2-seeking-parasites, or succumbing to respiratory acidosis in the presence of high concentrations of CO2 that are occasionally found in nature26,27. In contrast to CO2, flies are attracted to ethanol in all behavioral states, and invest twice as much time searching near ethanol compared to CO2. These behavioral differences reflect the fact that whereas CO2 is a generated by many natural processes, ethanol is a unique signature of yeast fermentation. Using genetic tools, we determined that the evolutionarily ancient ionotropic co-receptor IR25a is required for both CO2 and ethanol attraction, and that the receptors previously identified for CO2 avoidance are not involved. Our study lays the foundation for future research to determine the neural circuits underlying both state- and odorant-dependent decision making in Drosophila.

neuroscience↗