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INTRODUCTION: As aggregation underpins Tau toxicity, aggregation inhibitor peptides may have disease‐modifying potential. They are therefore currently being designed and target either the 306VQIVYK311 aggregation‐promoting hotspot found in all Tau isoforms or the 275VQIINK280 aggregation‐promoting hotspot found in 4R isoforms. However, for any Tau aggregation inhibitor to potentially be clinically relevant for other tauopathies, it should target both hotspots to suppress aggregation of Tau isoforms, be stable, cross the blood‐brain barrier, and rescue aggregation‐dependent Tau phenotypes in vivo. METHODS: We developed a retro‐inverso, stable D‐amino peptide, RI‐AG03 [Ac‐rrrrrrrrGpkyk(ac)iqvGr‐NH2], based on the 306VQIVYK311 hotspots which exhibit these disease‐relevant attributes. RESULTS: Unlike other aggregation inhibitors, RI‐AG03 effectively suppresses aggregation of multiple Tau species containing both hotspots in vitro and in vivo, is non‐toxic, and suppresses aggregation‐dependent neurodegenerative and behavioral phenotypes. DISCUSSION: RI‐AG03 therefore meets many clinically relevant requirements for an anti‐aggregation Tau therapeutic and should be explored further for its disease‐modifying potential for Tauopathies. Highlights: Our manuscript describes the development of a novel peptide inhibitor of Tau aggregation, a retro‐inverso, stable D‐amino peptide called RI‐AG03 that displays many clinically relevant attributes. We show its efficacy in preventing Tau aggregation in both in vitro and in vivo experimental models while being non‐toxic to cells. RI‐AG03 also rescues a biosensor cell line that stably expresses Tau repeat domains with the P301S mutation fused to Cer/Clo and rescues aggregation‐dependent phenotypes in vivo, suppressing neurodegeneration and extending lifespan.Collectively our data describe several properties and attributes of RI‐AG03 that make it a promising disease‐modifying candidate to explore for reducing pathogenic Tau aggregation in Tauopathies such as Alzheimer's disease. Given the real interest in reducing Tau aggregation and the potential clinical benefit of using such agents in clinical practice, RI‐AG03 should be investigated further for the treatment of Tauopathies after validation in mammalian models.Tau aggregation inhibitors are the obvious first choice as Tau‐based therapies as much of Tau‐mediated toxicity is aggregation dependent. Indeed, there are many research efforts focusing on this therapeutic strategy with aggregation inhibitors being designed against one of the two aggregation‐promoting hotspots of the Tau protein. To our knowledge, RI‐AG03 is the only peptide aggregation inhibitor that inhibits aggregation of Tau by targeting both aggregation‐promoting hotspot motifs simultaneously. As such, we believe that our study will have a significant impact on drug discovery efforts in this arena. [ABSTRACT FROM AUTHOR]

The actomyosin cytoskeleton is a crucial driver of morphogenesis. Yet how the behavior of large-scale cytoskeletal patterns in deforming tissues emerges from the interplay of geometry, genetics, and mechanics remains incompletely understood. Convergent extension in Drosophila melanogaster embryos provides the opportunity to establish a quantitative understanding of the dynamics of anisotropic non-muscle myosin II. Cell-scale analysis of protein localization in fixed embryos suggests that gene expression patterns govern myosin anisotropy via complex rules. However, technical limitations have impeded quantitative and dynamic studies of this process at the whole embryo level, leaving the role of geometry open. Here, we combine in toto live imaging with quantitative analysis of molecular dynamics to characterize the distribution of myosin anisotropy and the corresponding genetic patterning. We found pair rule gene expression continuously deformed, flowing with the tissue frame. In contrast, myosin anisotropy orientation remained approximately static and was only weakly deflected from the stationary dorsal-ventral axis of the embryo. We propose that myosin is recruited by a geometrically defined static source, potentially related to the embryo-scale epithelial tension, and account for transient deflections by cytoskeletal turnover and junction reorientation by flow. With only one parameter, this model quantitatively accounts for the time course of myosin anisotropy orientation in wild-type, twist, and even-skipped embryos, as well as embryos with perturbed egg geometry. Geometric patterning of the cytoskeleton suggests a simple physical strategy to ensure a robust flow and formation of shape.

Biological age, distinct from an individual's chronological age, has been studied extensively through predictive aging clocks. However, these clocks have limited accuracy in short time-scales. Here we trained deep learning models on fundus images from the EyePACS dataset to predict individuals' chronological age. Our retinal aging clocking, 'eyeAge', predicted chronological age more accurately than other aging clocks (mean absolute error of 2.86 and 3.30 years on quality-filtered data from EyePACS and UK Biobank, respectively). Additionally, eyeAge was independent of blood marker-based measures of biological age, maintaining an all-cause mortality hazard ratio of 1.026 even when adjusted for phenotypic age. The individual-specific nature of eyeAge was reinforced via multiple GWAS hits in the UK Biobank cohort. The top GWAS locus was further validated via knockdown of the fly homolog, Alk, which slowed age-related decline in vision in flies. This study demonstrates the potential utility of a retinal aging clock for studying aging and age-related diseases and quantitatively measuring aging on very short time-scales, opening avenues for quick and actionable evaluation of gero-protective therapeutics.

Tracking visual objects while maintaining stable gaze is complicated by the different computational requirements for figure-ground discrimination, and the distinct behaviors that these computations coordinate. Drosophila melanogaster uses smooth optomotor head and body movements to stabilize gaze, and impulsive saccades to pursue elongated vertical bars. Directionally selective motion detectors T4 and T5 cells provide inputs to large-field neurons in the lobula plate, which control optomotor gaze stabilization behavior. Here, we hypothesized that an anatomically parallel pathway represented by T3 cells, which provide inputs to the lobula, drives bar tracking body saccades. We combined physiological and behavioral experiments to show that T3 neurons respond omnidirectionally to the same visual stimuli that elicit bar tracking saccades, silencing T3 reduced the frequency of tracking saccades, and optogenetic manipulation of T3 acted on the saccade rate in a push-pull manner. Manipulating T3 did not affect smooth optomotor responses to large-field motion. Our results show that parallel neural pathways coordinate smooth gaze stabilization and saccadic bar tracking behavior during flight.

RAS GTPases are highly conserved proteins involved in the regulation of mitogenic signaling. We have previously described a novel Cullin 3 RING E3 ubiquitin ligase complex formed by the substrate adaptor protein LZTR1 that binds, ubiquitinates, and promotes proteasomal degradation of the RAS GTPase RIT1. In addition, others have described that this complex is also responsible for the ubiquitination of classical RAS GTPases. Here, we have analyzed the phenotypes of Lztr1 loss-of-function mutants in both fruit flies and mice and have demonstrated a biochemical preference for their RIT1 orthologs. Moreover, we show that Lztr1 is haplosufficient in mice and that embryonic lethality of the homozygous null allele can be rescued by deletion of Rit1. Overall, our results indicate that, in model organisms, RIT1 orthologs are the preferred substrates of LZTR1.

Sensory neurons enable animals to detect environmental changes and avoid harm. An intriguing open question concerns how the various attributes of sensory neurons arise in development. Drosophila melanogaster larvae undergo a behavioral transition by robustly activating a thermal nociceptive escape behavior during the second half of larval development (third instar). The Class IV dendritic arborization (C4da) neurons are multimodal sensors which tile the body wall of Drosophila larvae and detect nociceptive temperature, light, and mechanical force. In contrast to the increase in nociceptive behavior in the third instar, we find that ultraviolet light-induced Ca2+ activity in C4da neurons decreases during the same period of larval development. Loss of ecdysone receptor has previously been shown to reduce nociception in third instar larvae. We find that ligand-dependent activation of ecdysone signaling is sufficient to promote nociceptive responses in second instar larvae and suppress expression of subdued (encoding a TMEM16 channel). Reduction of subdued expression in second instar C4da neurons not only increases thermal nociception but also decreases the response to ultraviolet light. Thus, steroid hormone signaling suppresses subdued expression to facilitate the sensory switch of C4da neurons. This regulation of a developmental sensory switch through steroid hormone regulation of channel expression raises the possibility that ion channel homeostasis is a key target for tuning the development of sensory modalities.

The mechanism through which the brain senses the metabolic state, enabling an animal to regulate food consumption, and discriminate between nutritional and non-nutritional foods is a fundamental question. Flies choose the sweeter non-nutritive sugar, L-glucose, over the nutritive D-glucose if they are not starved. However, under starvation conditions, they switch their preference to D-glucose, and this occurs independent of peripheral taste neurons. Here, we found that eliminating the TRPγ channel impairs the ability of starved flies to choose D-glucose. This food selection depends on trpγ expression in neurosecretory cells in the brain that express diuretic hormone 44 (DH44). Loss of trpγ increases feeding, alters the physiology of the crop, which is the fly stomach equivalent, and decreases intracellular sugars and glycogen levels. Moreover, survival of starved trpγ flies is reduced. Expression of trpγ in DH44 neurons reverses these deficits. These results highlight roles for TRPγ in coordinating feeding with the metabolic state through expression in DH44 neuroendocrine cells.

Parkinson's disease (PD) is a common neurodegenerative disorder without effective disease-modifying therapeutics. Here, we establish a chemogenetic dopamine (DA) neuron ablation model in larval zebrafish with mitochondrial dysfunction and robustness suitable for high-content screening. We use this system to conduct an in vivo DA neuron imaging-based chemical screen and identify the Renin-Angiotensin-Aldosterone System (RAAS) inhibitors as significantly neuroprotective. Knockdown of the angiotensin receptor 1 (agtr1) in DA neurons reveals a cell-autonomous mechanism of neuroprotection. DA neuron-specific RNA-seq identifies mitochondrial pathway gene expression that is significantly restored by RAAS inhibitor treatment. The neuroprotective effect of RAAS inhibitors is further observed in a zebrafish Gaucher disease model and Drosophila pink1-deficient PD model. Finally, examination of clinical data reveals a significant effect of RAAS inhibitors in delaying PD progression. Our findings reveal the therapeutic potential and mechanisms of targeting the RAAS pathway for neuroprotection and demonstrate a salient approach that bridges basic science to translational medicine.

Drosophila suzukii (Matsumura) or spotted wing Drosophila is a worldwide invasive pest of soft‐ and stone‐fruit production. Female D. suzukii lay their eggs in ripening fruit and the hatched larvae damage fruit from the inside, rendering it unmarketable and causing significant economic loss. Current methods to reduce D. suzukii population in the field primarily rely on chemical insecticides which are not a sustainable long‐term solution and increase the risk of resistance developing. Several studies demonstrate that when D. suzukii encounter or coexist with other Drosophila on a food source, this is usually a disadvantage to D. suzukii, leading to reduced oviposition and increased larval mortality. These effects have potential to be exploited from a pest management perspective. In this review we summarise recent research articles focusing on the interspecific interactions between D. suzukii and other Drosophila species aimed at understanding how this drives D. suzukii behaviour. Potential semiochemical and microbiome impacts are postulated as determinants of D. suzukii behaviour. Development of control practices focusing on reducing D. suzukii populations and deterring them from laying eggs by utilising factors that drive their behaviour are discussed. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Can limb regeneration be induced? Few have pursued this question, and an evolutionarily conserved strategy has yet to emerge. This study reports a strategy for inducing regenerative response in appendages, which works across three species that span the animal phylogeny. In Cnidaria, the frequency of appendage regeneration in the moon jellyfish Aurelia was increased by feeding with the amino acid L-leucine and the growth hormone insulin. In insects, the same strategy induced tibia regeneration in adult Drosophila. Finally, in mammals, L-leucine and sucrose administration induced digit regeneration in adult mice, including dramatically from mid-phalangeal amputation. The conserved effect of L-leucine and insulin/sugar suggests a key role for energetic parameters in regeneration induction. The simplicity by which nutrient supplementation can induce appendage regeneration provides a testable hypothesis across animals.

Mechanistic studies of Drosophila lymph gland hematopoiesis are limited by the availability of cell-type-specific markers. Using a combination of bulk RNA-Seq of FACS-sorted cells, single-cell RNA-Seq, and genetic dissection, we identify new blood cell subpopulations along a developmental trajectory with multiple paths to mature cell types. This provides functional insights into key developmental processes and signaling pathways. We highlight metabolism as a driver of development, show that graded Pointed expression allows distinct roles in successive developmental steps, and that mature crystal cells specifically express an alternate isoform of Hypoxia-inducible factor (Hif/Sima). Mechanistically, the Musashi-regulated protein Numb facilitates Sima-dependent non-canonical, and inhibits canonical, Notch signaling. Broadly, we find that prior to making a fate choice, a progenitor selects between alternative, biologically relevant, transitory states allowing smooth transitions reflective of combinatorial expressions rather than stepwise binary decisions. Increasingly, this view is gaining support in mammalian hematopoiesis.

The subgenus Sophophora of Drosophila, which includes D. melanogaster, is an important model for the study of molecular evolution, comparative genomics, and evolutionary developmental biology. Numerous phylogenetic studies have examined species relationships in the well-known melanogaster, obscura, willistoni, and saltans species groups, as well as the relationships among these clades. In contrast, other species groups of Sophophora have been relatively neglected and have not been subjected to molecular phylogenetic analysis. Here, we focus on the endemic African Drosophila fima and dentissima lineages. We find that both these clades fall within the broadly defined melanogaster species group, but are otherwise distantly related to each other. The new phylogeny supports pervasive divergent and convergent evolution of male-specific grasping structures (sex combs). We discuss the implications of these results for defining the boundaries of the melanogaster species group, and weigh the relative merits of "splitting" and "lumping" approaches to the taxonomy of this key model system.

Introduction: As aggregation underpins Tau toxicity, aggregation inhibitor peptides may have disease-modifying potential. They are therefore currently being designed and target either the 306 VQIVYK 311 aggregation-promoting hotspot found in all Tau isoforms or the 275 VQIINK 280 aggregation-promoting hotspot found in 4R isoforms. However, for any Tau aggregation inhibitor to potentially be clinically relevant for other tauopathies, it should target both hotspots to suppress aggregation of Tau isoforms, be stable, cross the blood-brain barrier, and rescue aggregation-dependent Tau phenotypes in vivo., Methods: We developed a retro-inverso, stable D-amino peptide, RI-AG03 [Ac-rrrrrrrrGpkyk(ac)iqvGr-NH2], based on the 306 VQIVYK 311 hotspots which exhibit these disease-relevant attributes., Results: Unlike other aggregation inhibitors, RI-AG03 effectively suppresses aggregation of multiple Tau species containing both hotspots in vitro and in vivo, is non-toxic, and suppresses aggregation-dependent neurodegenerative and behavioral phenotypes., Discussion: RI-AG03 therefore meets many clinically relevant requirements for an anti-aggregation Tau therapeutic and should be explored further for its disease-modifying potential for Tauopathies., Highlights: Our manuscript describes the development of a novel peptide inhibitor of Tau aggregation, a retro-inverso, stable D-amino peptide called RI-AG03 that displays many clinically relevant attributes. We show its efficacy in preventing Tau aggregation in both in vitro and in vivo experimental models while being non-toxic to cells. RI-AG03 also rescues a biosensor cell line that stably expresses Tau repeat domains with the P301S mutation fused to Cer/Clo and rescues aggregation-dependent phenotypes in vivo, suppressing neurodegeneration and extending lifespan. Collectively our data describe several properties and attributes of RI-AG03 that make it a promising disease-modifying candidate to explore for reducing pathogenic Tau aggregation in Tauopathies such as Alzheimer's disease. Given the real interest in reducing Tau aggregation and the potential clinical benefit of using such agents in clinical practice, RI-AG03 should be investigated further for the treatment of Tauopathies after validation in mammalian models. Tau aggregation inhibitors are the obvious first choice as Tau-based therapies as much of Tau-mediated toxicity is aggregation dependent. Indeed, there are many research efforts focusing on this therapeutic strategy with aggregation inhibitors being designed against one of the two aggregation-promoting hotspots of the Tau protein. To our knowledge, RI-AG03 is the only peptide aggregation inhibitor that inhibits aggregation of Tau by targeting both aggregation-promoting hotspot motifs simultaneously. As such, we believe that our study will have a significant impact on drug discovery efforts in this arena., (© 2024 The Author(s). Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Simple Summary: Hoverflies are a diverse family of insects (6000+ species) providing multiple ecosystem services and direct benefits to society, for example, in pollination and pest control. The extent to which hoverflies can benefit society depends on how well their basics are known, i.e., taxonomy (classification), biology and ecology. Small and inconspicuous hoverflies such as those of the genera Chrysogaster, Melanogaster, Lejogaster, Orthonevra and Riponnensia (tribe Brachyopini) do not usually catch the attention of the general public neither of scientists, and their classification is often poorly known at least in areas of their range. So, the aim of the present work is to gain knowledge in the classification of hoverflies by studying the species of the five genera above-mentioned in the Iberian Peninsula, which has one of the highest biodiversity levels in Europe. We discovered and described two new species from Spain, promoted a subspecies to species and proposed other nomenclatural acts to stabilise these hoverflies' classification in Europe. Our results are reinforced with DNA analysis to locate the studied species in a wider systematic framework within the Brachyopini. Five genera of Brachyopini, Chrysogaster Meigen, 1800, Melanogaster Rondani, 1857, Lejogaster Rondani, 1857, Orthonevra Macquart, 1829 and Riponnensia Maibach et al. 1994a are here revised from the Iberian region. Two new species, Melanogaster baetica Ricarte and Nedeljković, sp. n. and Orthonevra arcana Ricarte and Nedeljković sp. n., are described from Spain, and a third species, Chrysogaster coerulea Strobl in Czerny and Strobl, 1909 stat. n., is reinstated as valid and redescribed. A lectotype is designated for Orthonevra plumbago (Loew, 1840). The holotype of Orthonevra incisa (Loew, 1843) and the lectotype of O. plumbago are described in detail and illustrated. Melanogaster baetica sp. n. is similar to Melanogaster parumplicata (Loew, 1840) in male genitalia morphology, while O. arcana sp. n. is similar to O. incisa in the entirely-pollinose sternum I and the conspicuous incision on the posterior margin of tergum V in female. The first Iberian record of Chrysogaster rondanii Maibach and Goeldlin de Tiefenau, 1995 is provided, whilst Melanogaster aerosa is removed from the Iberian checklist of Syrphidae. Identification keys are presented to the five Brachyopini genera and 18 species now reported from the Iberian Peninsula (Chrysogaster, 6 spp.; Lejogaster, 2 spp.; Melanogaster, 3 spp.; Orthonevra, 5 spp.; Riponnensia, 2 spp.). COI (Cytochrome c oxidase subunit I) barcodes of the two new species plus C. coerulea, Chrysogaster solstitialis (Fallén, 1817), Orthonevra nobilis (Fallén, 1817) and Orthonevra frontalis (Loew, 1843) were successfully obtained from Spanish specimens. A COI-based tree was produced to locate these taxa in a wider systematic framework within the tribe. [ABSTRACT FROM AUTHOR]

During a survey conducted from 2018 to 2021, six hoverfly species were registered on the territory of Serbia for the first time: Chalcosyrphus pannonicus (Oldenberg, 1916), Chrysogaster coemiteriorum (Linnaeus, 1758), Eristalinus taeniops (Wiedemann, 1818), Melanogaster parumplicata (Loew, 1840), Merodon testaceus Sack, 1913 and Psilota atra (Fallén, 1817). Data about new records are presented.

Six additional species of hover flies of the subfamily Eristalinae are recorded from Ukraine for the first time: Criorhina pachymera Egger, 1858, Hammerschmidtia ferruginea (Fallén, 1817), Melanogaster parumplicata (Loew, 1840), Orthonevra erythrogona (Malm, 1863), Sphiximorpha garibaldii Rondani, 1860, and Temnostoma angustistriatum Krivosheina, 2002. Distributions of these species are summarized and species diagnoses are provided. Updated key to males of the European species of the genus Melanogaster including a little-known M. jaroslavensis (Stackelberg, 1922) is proposed.

Five genera of Brachyopini, Chrysogaster Meigen, 1800, Melanogaster Rondani, 1857, Lejogaster Rondani, 1857, Orthonevra Macquart, 1829 and Riponnensia Maibach et al. 1994a are here revised from the Iberian region. Two new species, Melanogaster baetica Ricarte and Nedeljković, sp. n. and Orthonevra arcana Ricarte and Nedeljković sp. n., are described from Spain, and a third species, Chrysogaster coerulea Strobl in Czerny and Strobl, 1909 stat. n., is reinstated as valid and redescribed. A lectotype is designated for Orthonevra plumbago (Loew, 1840). The holotype of Orthonevra incisa (Loew, 1843) and the lectotype of O. plumbago are described in detail and illustrated. Melanogaster baetica sp. n. is similar to Melanogaster parumplicata (Loew, 1840) in male genitalia morphology, while O. arcana sp. n. is similar to O. incisa in the entirely-pollinose sternum I and the conspicuous incision on the posterior margin of tergum V in female. The first Iberian record of Chrysogaster rondanii Maibach and Goeldlin de Tiefenau, 1995 is provided, whilst Melanogaster aerosa is removed from the Iberian checklist of Syrphidae. Identification keys are presented to the five Brachyopini genera and 18 species now reported from the Iberian Peninsula (Chrysogaster, 6 spp.; Lejogaster, 2 spp.; Melanogaster, 3 spp.; Orthonevra, 5 spp.; Riponnensia, 2 spp.). COI (Cytochrome c oxidase subunit I) barcodes of the two new species plus C. coerulea, Chrysogaster solstitialis (Fallén, 1817), Orthonevra nobilis (Fallén, 1817) and Orthonevra frontalis (Loew, 1843) were successfully obtained from Spanish specimens. A COI-based tree was produced to locate these taxa in a wider systematic framework within the tribe.

Differences in the level, timing, or location of gene expression can contribute to alternative phenotypes at the molecular and organismal level. Understanding the origins of expression differences is complicated by the fact that organismal morphology and gene regulatory networks could potentially vary even between closely related species. To assess the scope of such changes, we used high-resolution imaging methods to measure mRNA expression in blastoderm embryos of Drosophila yakuba and Drosophila pseudoobscura and assembled these data into cellular resolution atlases, where expression levels for 13 genes in the segmentation network are averaged into species-specific, cellular resolution morphological frameworks. We demonstrate that the blastoderm embryos of these species differ in their morphology in terms of size, shape, and number of nuclei. We present an approach to compare cellular gene expression patterns between species, while accounting for varying embryo morphology, and apply it to our data and an equivalent dataset for Drosophila melanogaster. Our analysis reveals that all individual genes differ quantitatively in their spatio-temporal expression patterns between these species, primarily in terms of their relative position and dynamics. Despite many small quantitative differences, cellular gene expression profiles for the whole set of genes examined are largely similar. This suggests that cell types at this stage of development are conserved, though they can differ in their relative position by up to 3-4 cell widths and in their relative proportion between species by as much as 5-fold. Quantitative differences in the dynamics and relative level of a subset of genes between corresponding cell types may reflect altered regulatory functions between species. Our results emphasize that transcriptional networks can diverge over short evolutionary timescales and that even small changes can lead to distinct output in terms of the placement and number of equivalent cells.

The primary means of reducing malaria transmission is through reduction in longevity in days of the adult female stage of the Anopheles vector. However, assessing chronological age is limited to crude physiologic methods which categorize the females binomially as either very young (nulliparous) or not very young (parous). Yet the epidemiologically relevant reduction in life span falls within the latter category. Age-grading methods that delineate chronological age, using accurate molecular surrogates based upon gene expression profiles, will allow quantification of the longevity-reducing effects of vector control tools aimed at the adult, female mosquito. In this study, microarray analyses of gene expression profiles in the African malaria vector Anopheles gambiae were conducted during natural senescence of females in laboratory conditions. Results showed that detoxification-related and stress-responsive genes were up-regulated as mosquitoes aged. A total of 276 transcripts had age-dependent expression, independently of blood feeding and egg laying events. Expression of 112 (40.6%) of these transcripts increased or decreased monotonically with increasing chronologic age. Seven candidate genes for practical age assessment were tested by quantitative gene amplification in the An. gambiae G3 strain in a laboratory experiment and the Mbita strain in field enclosures set up in western Kenya under conditions closely resembling natural ones. Results were similar between experiments, indicating that senescence is marked by changes in gene expression and that chronological age can be gauged accurately and repeatedly with this method. These results indicate that the method may be suitable for accurate gauging of the age in days of field-caught, female An. gambiae.

Light-activated large ventral lateral clock neurons (large LNv) modulate behavioral arousal and sleep in Drosophila while their counterparts, the small LNv (s-LNv) are important for circadian behavior. Recently, it has been proposed that the pattern of day-night locomotor behavioral activity is mediated by two anatomically distinct oscillators composed of a morning oscillator in the small LNv and an evening oscillator in the lateral dorsal neurons and an undefined number of dorsal pacemaker neurons. This contrasts with a circuit described by network models which are not as anatomically constrained. By selectively ablating the small LNv while sparing the large LNv, we tested the relative importance of the small and large LNv for regulating morning behavior of animals living in standard light/dark cycles. Behavioral anticipation of the onset of morning and the high amplitude morning startle response which coincides with light onset are preserved in small LNv functionally-ablated animals. However, the amplitude of the morning behavioral peak is severely attenuated in these animals during the transition from regular light/dark cycles to constant darkness, providing further support that small LNv are necessary for circadian behavior. The large LNv, in combination with the network of other circadian neurons, in the absence of functional small LNv are sufficient for the morning anticipation and the high amplitude light-activated morning startle response.

Several techniques have been developed to study specific gene function in loss-of-function situations. In Drosophila melanogaster, RNAi and the generation of mutant clones are widely used. However, both techniques have the limitation that there is a significant time lag before gene function is abolished. Given the relatively rapid development of Drosophila, such perdurance is a serious impediment to study gene function. Here we describe the adaptation of the anchor-away technique for use in Drosophila. Anchor-away was originally developed in yeast to quickly and efficiently abrogate the function of nuclear proteins by sequestering - anchoring - themaway in a different cellular compartment. The required components are present in the cells, and the systemis triggered by the addition of rapamycin, resulting in a rapid generation of a loss-of-function situation. We provide here proof of principle for the system by producing loss-of-function situations for two nuclear proteins - Pygopus and Brinker. The system allows to study the requirement of any protein during any time window, and at the same time circumvents difficulties, such as off-target effects or variable phenotypes, which are inherent in other techniques, for example RNAi. [ABSTRACT FROM AUTHOR]

The detection, discrimination, and behavioral responses to chemical cues in the environment can have marked effects on organismal survival and reproduction, eliciting attractive or aversive behavior. To gain insight into mechanisms mediating this hedonic valence, we applied thirty generations of divergent artificial selection for Drosophila melanogaster olfactory behavior. We independently selected for positive and negative behavioral responses to two ecologically relevant chemical compounds: 2,3-butanedione and cyclohexanone. We also tested the correlated responses to selection by testing behavioral responses to other odorants and life history traits. Measurements of behavioral responses of the selected lines and unselected controls to additional odorants showed that the mechanisms underlying responses to these odorants are, in some cases, differentially affected by selection regime and generalization of the response to other odorants was only detected in the 2,3-butanedione selection lines. Food consumption and lifespan varied with selection regime and, at times, sex. An analysis of gene expression of both selection regimes identified multiple differentially expressed genes. New genes and genes previously identified in mediating olfactory behavior were identified. In particular, we found functional enrichment of several gene ontology terms, including cell-cell adhesion and sulfur compound metabolic process, the latter including genes belonging to the glutathione S-transferase family. These findings highlight a potential role for glutathione S-transferases in the evolution of hedonic valence to ecologically relevant volatile compounds and set the stage for a detailed investigation into mechanisms by which these genes mediate attraction and aversion. [ABSTRACT FROM AUTHOR]

Homing based gene drives (HGD) possess the potential to spread linked cargo genes into natural populations and are poised to revolutionize population control of animals. Given that host encoded genes have been identified that are important for pathogen transmission, targeting these genes using guide RNAs as cargo genes linked to drives may provide a robust method to prevent disease transmission. However, effectiveness of the inclusion of additional guide RNAs that target separate genes has not been thoroughly explored. To test this approach, we generated a split-HGD in Drosophila melanogaster that encoded a drive linked effector consisting of a second gRNA engineered to target a separate host-encoded gene, which we term a gRNA-mediated effector (GME). This design enabled us to assess homing and knockout efficiencies of two target genes simultaneously, and also explore the timing and tissue specificity of Cas9 expression on cleavage/homing rates. We demonstrate that inclusion of a GME can result in high efficiency of disruption of both genes during super-Mendelian propagation of split-HGD. Furthermore, both genes were knocked out one generation earlier than expected indicating the robust somatic expression of Cas9 driven by Drosophila germline-limited promoters. We also assess the efficiency of 'shadow drive' generated by maternally deposited Cas9 protein and accumulation of drive-induced resistance alleles along multiple generations, and discuss design principles of HGD that could mitigate the accumulation of resistance alleles while incorporating a GME. [ABSTRACT FROM AUTHOR]

Locomotion is an ancient and fundamental output of the nervous system required for animals to perform many other complex behaviors. Although the formation of motor circuits is known to be under developmental control of transcriptional mechanisms that define the fates and connectivity of the many neurons, glia and muscle constituents of these circuits, relatively little is known about the role of posttranscriptional regulation of locomotor behavior. MicroRNAs have emerged as a potentially rich source of modulators for neural development and function. In order to define the microRNAs required for normal locomotion in Drosophila melanogaster, we utilized a set of transgenic Gal4-dependent competitive inhibitors (microRNA sponges, or miR-SPs) to functionally assess ca. 140 high-confidence Drosophila microRNAs using automated quantitative movement tracking systems followed by multiparametric analysis. Using ubiquitous expression of miR-SP constructs, we identified a large number of microRNAs that modulate aspects of normal baseline adult locomotion. Addition of temperature-dependent Gal80 to identify microRNAs that act during adulthood revealed that the majority of these microRNAs play developmental roles. Comparison of ubiquitous and neural-specific miR-SP expression suggests that most of these microRNAs function within the nervous system. Parallel analyses of spontaneous locomotion in adults and in larvae also reveal that very few of the microRNAs required in the adult overlap with those that control the behavior of larval motor circuits. These screens suggest that a rich regulatory landscape underlies the formation and function of motor circuits and that many of these mechanisms are stage and/or parameter-specific. [ABSTRACT FROM AUTHOR]

BackgroundNatural selection and genetic drift are major forces responsible for temporal genetic changes in populations. Furthermore, these evolutionary forces may interact with each other. Here we study the impact of an ongoing adaptive process at the molecular genetic level by analyzing the temporal genetic changes throughout 40 generations of adaptation to a common laboratory environment. Specifically, genetic variability, population differentiation and demographic structure were compared in two replicated groups of Drosophila subobscura populations recently sampled from different wild sources.ResultsWe found evidence for a decline in genetic variability through time, along with an increase in genetic differentiation between all populations studied. The observed decline in genetic variability was higher during the first 14 generations of laboratory adaptation. The two groups of replicated populations showed overall similarity in variability patterns. Our results also revealed changing demographic structure of the populations during laboratory evolution, with lower effective population sizes in the early phase of the adaptive process. One of the ten microsatellites analyzed showed a clearly distinct temporal pattern of allele frequency change, suggesting the occurrence of positive selection affecting the region around that particular locus.ConclusionGenetic drift was responsible for most of the divergence and loss of variability between and within replicates, with most changes occurring during the first generations of laboratory adaptation. We also found evidence suggesting a selective sweep, despite the low number of molecular markers analyzed. Overall, there was a similarity of evolutionary dynamics at the molecular level in our laboratory populations, despite distinct genetic backgrounds and some differences in phenotypic evolution.

A new spatio-temporal coordinate framework for studying three-dimensional patterns of gene expression in the Drosophila blastoderm is presented that takes account of previously undetected morphological movements.BackgroundTo accurately describe gene expression and computationally model animal transcriptional networks, it is essential to determine the changing locations of cells in developing embryos.ResultsUsing automated image analysis methods, we provide the first quantitative description of temporal changes in morphology and gene expression at cellular resolution in whole embryos, using the Drosophila blastoderm as a model. Analyses based on both fixed and live embryos reveal complex, previously undetected three-dimensional changes in nuclear density patterns caused by nuclear movements prior to gastrulation. Gene expression patterns move, in part, with these changes in morphology, but additional spatial shifts in expression patterns are also seen, supporting a previously proposed model of pattern dynamics based on the induction and inhibition of gene expression. We show that mutations that disrupt either the anterior/posterior (a/p) or the dorsal/ventral (d/v) transcriptional cascades alter morphology and gene expression along both the a/p and d/v axes in a way suggesting that these two patterning systems interact via both transcriptional and morphological mechanisms.ConclusionOur work establishes a new strategy for measuring temporal changes in the locations of cells and gene expression patterns that uses fixed cell material and computational modeling. It also provides a coordinate framework for the blastoderm embryo that will allow increasingly accurate spatio-temporal modeling of both the transcriptional control network and morphogenesis.

A suite of methods that provide the first quantitative three-dimensional description of gene expression and morphology with cellular resolution in whole Drosophila embryos is described.BackgroundTo model and thoroughly understand animal transcription networks, it is essential to derive accurate spatial and temporal descriptions of developing gene expression patterns with cellular resolution.ResultsHere we describe a suite of methods that provide the first quantitative three-dimensional description of gene expression and morphology at cellular resolution in whole embryos. A database containing information derived from 1,282 embryos is released that describes the mRNA expression of 22 genes at multiple time points in the Drosophila blastoderm. We demonstrate that our methods are sufficiently accurate to detect previously undescribed features of morphology and gene expression. The cellular blastoderm is shown to have an intricate morphology of nuclear density patterns and apical/basal displacements that correlate with later well-known morphological features. Pair rule gene expression stripes, generally considered to specify patterning only along the anterior/posterior body axis, are shown to have complex changes in stripe location, stripe curvature, and expression level along the dorsal/ventral axis. Pair rule genes are also found to not always maintain the same register to each other.ConclusionThe application of these quantitative methods to other developmental systems will likely reveal many other previously unknown features and provide a more rigorous understanding of developmental regulatory networks.

Drosophila suzukii (Matsumara) also called Spotted Wing Drosophila (SWD), is an invasive pest species originally from Asia that has now spread widely across Europe and North America. The majority of drosophilids including the best known Drosophila melanogaster only breed on decaying fruits. On the contrary, the presence of a strong serrated ovipositor and behavioural and metabolic adaptations allow D. suzukii to lay eggs inside healthy, ripening fruits that are still on the plant. Here we present an analysis of the rhythmic locomotor activity behaviour of D. suzukii under several laboratory settings. Moreover, we identify the canonical clock neurons in this species by reporting the expression pattern of the major clock proteins in the brain. Interestingly, a fundamentally similar organisation of the clock neurons network between D. melanogaster and D. suzukii does not correspond to similar characteristics in rhythmic locomotor activity behaviour.

Members of the Protein Kinase D (PKD) family are involved in numerous cellular processes in mammals, including cell survival after oxidative stress, polarized transport of Golgi vesicles, as well as cell migration and invasion. PKD proteins belong to the PKC/CAMK class of serine/threonine kinases, and transmit diacylglycerol-regulated signals. Whereas three PKD isoforms are known in mammals, Drosophila melanogaster contains a single PKD homolog. Previous analyses using overexpression and RNAi studies indicated likewise multi-facetted roles for Drosophila PKD, including the regulation of secretory transport and actin-cytoskeletal dynamics. Recently, involvement in growth regulation has been proposed based on the hypomorphic dPKDH allele. We have generated PKD null alleles that are homozygous viable without apparent phenotype. They largely match control flies regarding fertility, developmental timing and weight. Males, but not females, are slightly shorter lived and starvation sensitive. Furthermore, migration of pole cells in embryos and border cells in oocytes appears normal. PKD mutants tolerate heat, cold and osmotic stress like the control but are sensitive to oxidative stress, conforming to the described role for mammalian PKDs. A candidate screen to identify functionally redundant kinases uncovered genetic interactions of PKD with Pkcd, sqa and Drak mutants, further supporting the role of PKD in oxidative stress response, and suggesting its involvement in starvation induced autophagy and regulation of cytoskeletal dynamics. Overall, PKD appears dispensable for fly development and survival presumably due to redundancy, but influences environmental responses. [ABSTRACT FROM AUTHOR]

Drosophila suzukii (Matsumara) also called Spotted Wing Drosophila (SWD), is an invasive pest species originally from Asia that has now spread widely across Europe and North America. The majority of drosophilids including the best known Drosophila melanogaster only breed on decaying fruits. On the contrary, the presence of a strong serrated ovipositor and behavioural and metabolic adaptations allow D. suzukii to lay eggs inside healthy, ripening fruits that are still on the plant. Here we present an analysis of the rhythmic locomotor activity behaviour of D. suzukii under several laboratory settings. Moreover, we identify the canonical clock neurons in this species by reporting the expression pattern of the major clock proteins in the brain. Interestingly, a fundamentally similar organisation of the clock neurons network between D. melanogaster and D. suzukii does not correspond to similar characteristics in rhythmic locomotor activity behaviour. [ABSTRACT FROM AUTHOR]

Nutrients which are present in the diet of an organism play a very important role in the fitness, life span, growth, development, and health of an organism. In the present study, embryos and larva were exposed to various concentrations of organic green tea and organic white tea. The results showed that the larvae were exposed to higher concentrations which were slower to develop and exhibited a dramatic decline in the number of emerged offspring. The rate of the development of larva to pupa and pupa to adult was slower in case of organic white tea media treated flies when compared to normal and organic green tea media treated flies. Collectively, these studies showed that the organic green tea provides required nutrients for rate of the development of larvae to pupa and normal media provides required nutrients for rate of the development of pupa to adult when compare to that of organic white tea media also higher concentrations adversely impact on the pre-adult development of Drosophila melanogaster. [ABSTRACT FROM AUTHOR]

In Drosophila melanogaster, pupal behavior is very essential event to complete the life cycle successfully. Drosophila consists of four stages in the life cycle they are egg, larva, pupa, and adult. Important aspect in the life cycle of D. melanogaster is the capacity of the 3rd instar larva to pupate on a suitable surface. In this study, larva was reared on organic green tea, white tea, and wheat cream agar media preferred to pupate significantly greater number on glass surface when compared to cotton and media. Larva which feeds on organic white tea media was moved to greater height when compare to larva feeds on organic green tea and wheat cream agar media. The data showed that nutrients which are present in organic white tea provide sufficient energy for larva to move higher height from the media and pupate on glass surface. Hence, data suggested that organic white tea had significant effects on the pupal behavior of D. melanogaster when compare to organic green tea and wheat cream agar media. [ABSTRACT FROM AUTHOR]

Two experiments have been performed in young (7 days old),  middle-aged (28 days old) and old (49 days old) Drosophila melanogaster. In Experiment 1, the inhibitory conditioning of the Proboscis Extension Response (PER) to sucrose was displayed under three Inter-Trial-Interval (ITI) schedules: 1, 2 or 4 minutes. The results did not reveal any age-related impairment of short-term-memory. The PER suppression performance was higher in middle-aged and old flies than in young ones, whatever the ITI. In Experiment 2, the habituation of the PER to sucrose was induced to investigate the hypothesis of an age-related increase of the non associative processes involvement (sensory adaptation, motor fatigue) in the PER suppression. The results showed that  once such peripheral effects were removed, suppression performances no longer varied with age.

Multicellular development is driven by regulatory programs that orchestrate the transcription of protein-coding and noncoding genes. To decipher this genomic regulatory code, and to investigate the developmental relevance of noncoding transcription, we compared genome-wide promoter activity throughout embryogenesis in 5 Drosophila species. Core promoters, generally not thought to play a significant regulatory role, in fact impart restrictions on the developmental timing of gene expression on a global scale. We propose a hierarchical regulatory model in which core promoters define broad windows of opportunity for expression, by defining a range of transcription factors from which they can receive regulatory inputs. This two-tiered mechanism globally orchestrates developmental gene expression, including extremely widespread noncoding transcription. The sequence and expression specificity of noncoding RNA promoters are evolutionarily conserved, implying biological relevance. Overall, this work introduces a hierarchical model for developmental gene regulation, and reveals a major role for noncoding transcription in animal development.