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Bisphenol A (BPA), an endocrine-disrupting chemical, poses significant health problems due to its induction of oxidative stress, inflammation, etc. Whereas Ficus exasperata Vahl leaf (FEVL) was reported for its ethnopharmacological properties against several ailments owing to its antioxidant, anti-inflammatory properties, etc. Here, we aim to elucidate and identify the bioactive compounds of aqueous extract of FEVL (AEFEVL) against BPA-induced toxicity using in vivo and in silico assessments. To determine the BPA toxicity mechanism and safe doses of AEFEVL, graded doses of BPA (0–400 μM) and AEFEVL (0–2.0 mg/10 g diets) were separately fed to flies to evaluate survival rates and specific biochemical markers. The mitigating effect of AEFEVL (0.5 and 1.0 mg/10 g diet) against BPA (100 and 200 μM)-induced toxicity in the flies after 7-day exposure was also carried out. Additionally, molecular docking analysis of BPA and BPA-o-quinone (BPAQ) against selected antioxidant targets, and HPLC–MS-revealed AEFEVL compounds against Keap-1 and IKKβ targets, followed by ADMET analysis, was conducted. Emergence rate, climbing ability, acetylcholinesterase, monoamine oxidase-B, and glutathione-S-transferase activities, and levels of total thiols, non-protein thiols, nitric oxide, protein carbonyl, malondialdehyde, and cell viability were evaluated. BPA-induced altered biochemical and behavioral parameters were significantly mitigated by AEFEVL in the flies (p < 0.05). BPAQ followed by BPA exhibited higher inhibitory activity, and epigallocatechin (EGC) showed the highest inhibitory activity among the AEFEVL compounds with desirable ADMET properties. Conclusively, our findings revealed that EGC might be responsible for the mitigative effect displayed by AEFEVL in BPA-induced toxicity in D. melanogaster. [ABSTRACT FROM AUTHOR]

The strength of molecular interactions is characterized by their dissociation constants (KD). Only high-affinity interactions (KD ≤ 10−8 M) are extensively investigated and support binary on/off switches. However, such analyses have discounted the presence of low-affinity binders (KD > 10−5 M) in the cellular environment. We assess the potential influence of low-affinity binders on high-affinity interactions. By employing Gillespie stochastic simulations and continuous methods, we demonstrate that the presence of low-affinity binders can alter the kinetics and the steady state of high-affinity interactions. We refer to this effect as 'herd regulation' and have evaluated its possible impact in two different contexts including sex determination in Drosophila melanogaster and in signalling systems that employ molecular thresholds. We have also suggested experiments to validate herd regulation in vitro. We speculate that low-affinity binders are prevalent in biological contexts where the outcomes depend on molecular thresholds impacting homoeostatic regulation. [ABSTRACT FROM AUTHOR]

Similar to the physiological importance of gut microbiomes, recent works have shown that insect ectomicrobiotas can mediate defensive colonization resistance against fungal parasites that infect via cuticle penetration. Here we show that engineering the entomopathogenic fungus Metarhizium robertsii with a potent antibacterial moricin gene from silkworms substantially enhances the ability of the fungus to kill mosquitos, locusts, and two Drosophila species. Further use of Drosophila melanogaster as an infection model, quantitative microbiome analysis reveals that engineered strains designed to suppress insect cuticular bacteria additionally disrupt gut microbiomes. An overgrowth of harmful bacteria such as the opportunistic pathogens of Providencia species is detected that can accelerate insect death. In support, quantitative analysis of antimicrobial genes in fly fat bodies and guts indicates that topical fungal infections result in the compromise of intestinal immune responses. In addition to providing an innovative strategy for improving the potency of mycoinsecticides, our data solidify the importance of both the ecto- and endo-microbiomes in maintaining insect wellbeing. Genetic engineering of Metarhizium robertsii with a silkworm antibacterial gene substantially boosts fungal potency against different insects. Both the cuticle and gut microbiomes can be disrupted to accelerate insect death after fungal infection. [ABSTRACT FROM AUTHOR]

Insects are established models for understanding host-pathogen interactions and innate immune mechanisms. The innate immune system in insects is highly efficient in recognizing and opposing pathogens that cause detrimental effects during infection. The cuticular layer which covers the superficial layer of the insect body participates in host defense and wound healing by inducing innate immune responses. Previous studies have started to address the involvement of cuticular genes in conferring resistance to insect pathogens, particularly those that infect by disrupting the insect cuticle. For example, the cuticular gene Transglutaminase (TG) in Drosophila melanogaster plays a structural role in cuticle formation and blood coagulation and also possesses immune properties against pathogenic infection. However, more information is becoming available about the immune function of other cuticular gene families in insects. In this review, we aim to highlight the recent advances in insect cuticular immunity and address the necessity of pursuing further research to fill the existing gaps in this important field of insect immunology. This information will lead to novel strategies for the efficient management of agricultural insect pests and vectors of plant and human disease. [ABSTRACT FROM AUTHOR]

Across the globe, many species of insects are facing population decline. This is largely driven by anthropogenic changes to the environment, including the widespread exposure of invertebrates to endocrine disrupting chemicals (EDCs), which impair fertility. To test whether generations of Drosophila melanogaster born from parents exposed to a common dietary EDC, equol, could recover reproductive function, we quantified the reproductive capacity of the two subsequent generations. Using a novel suite of flow cytometry assays to assess sperm functionality in real time, we find that sperm function is compromised across three generations, even after non-exposed in individuals contribute to the breeding population. Though the sex ratio alters in response to EDC exposure, favouring the survival of female offspring, most lineages with ancestral EDC exposure exhibit persistent subfertility in both the male and female. Male offspring with ancestral EDC exposure present with reduced fertility and dysfunctional spermatozoa, whereby spermatozoa are metabolically stressed, lack DNA integrity and present with permanent epigenetic alterations. Across generations, male and female offspring demonstrate distinct patterns of reproductive characteristics, depending upon the specific lineage of EDC exposure. Our results illustrate how dietary EDCs present in agricultural plants could promote transgenerational subfertility and contribute to declining insect populations. [ABSTRACT FROM AUTHOR]

As an important model organism, Drosophila melanogaster has unique advantages in biological research because of its short life span, low culture cost, rich mutant resources and relatively simple gene operation. In recent years, with the vigorous development of food science, Drosophila melanogaster shows unique application value in screening new health food and pharmacological research. This paper reviews the methods and applications of establishing models of common human diseases and aging of Drosophila melanogaster, which lays a foundation for the study of the mechanism of diseases and aging, as well as the research and development of health food and drugs. [ABSTRACT FROM AUTHOR]

Mate choice is a key trait that determines fitness for most sexually reproducing organisms, with females often being the choosy sex. Female preference often results in strong selection on male traits that can drive rapid divergence of traits and preferences between lineages, leading to reproductive isolation. Despite this fundamental property of female mate choice, very few loci have been identified that contribute to mate choice and reproductive isolation. We used a combination of population genetics, quantitative complementation tests, and behavioural assays to demonstrate that alan shepard and Neuroglian contribute to female mate choice, and could contribute to partial reproductive isolation between populations of Drosophila melanogaster. Our study is among the first to identify genes that contribute to female mate preference in this historically important system, where female preference is an active premating barrier to reproduction. The identification of loci that are primarily known for their roles in neurodevelopment provides intriguing questions of how female mate preference evolves in populations via changes in sensory system and higher learning brain centres. Graphical Abstract [ABSTRACT FROM AUTHOR]

Body size is a trait that shapes many aspects of a species' development and evolution. Larger body size is often beneficial in animals, but it can also be associated with life history costs in natural systems. Similarly, miniaturization, the evolution of extremely small adult body size, is found in every major animal group, yet carries its own life history trade-offs. Given that these effects can depend on an animal's environment and life stage and have mainly been studied in species that are already specialized for their size, the life history changes associated with evolutionary shifts in body size warrant additional investigation. Here, we used Drosophila melanogaster populations that had undergone over 400 generations of artificial selection on body size to investigate the changes in life history traits associated with the evolution of extremely large and extremely small body sizes. Populations selected for small body size experienced strong trade-offs in multiple life history traits, including reduced female fecundity and lower juvenile viability. Although we found positively correlated changes in egg size associated with selection for both large and small body size, after adjusting for female body size, females from populations selected for large size had the lowest relative investment per egg and females from populations selected for small size had the highest relative investment per egg. Taken together, our results suggest that egg size may be a key constraint on the evolution of body size in D. melanogaster, providing insight into the broader phenomenon of body size evolution in insects. Graphical Abstract [ABSTRACT FROM AUTHOR]

To investigate the impact of sodium cyclamate on the fecundity, development, and locomotor abilities, this study using Drosophila melanogaster medium with varying concentrations of sodium cyclamate, the pupation time and total pupal count within a 5 d period were assessed as indicators of reproductive capacity. Additionally, the study analyzed the initiation of eclosion, the total number of emerged flies within 5 d, and the weight and body length of drosophila to elucidate the influence of sodium cyclamate on fruit fly development. The changes of locomotor abilities were evaluated in climbing index. The results revealed that a 1 mg/mL sodium cyclamate culture medium enhanced reproductive capacity, positively influenced the growth and development of Drosophila melanogaster, while reducing locomotor abilities. However, these effects did not reach statistical significant level. Conversely, sodium cyclamate concentrations ranging from 2 to 8 mg/mL exert inhibitory effects on reproduction, development, and locomotor abilities. The inhibitory effects became more pronounced with increasing concentration. Compared with 0, sodium cyclamate culture medium with concentrations ranging from 4 to 8 mg/mL exhibited significant differences in the reproductive, development and locomotor abilities（t=2.622 to 5.000, P<0.05）. Specifically, the 4 mg/mL sodium cyclamate culture medium led to a highly significant difference in the weight of female Drosophila melanogaster and the locomotor abilities of male Drosophila melanogaster （t=5.831 and 3.801, P<0.01）. The 8 mg/mL sodium cyclamate culture medium resulted in highly significant differences in the weight, length of female fruit flies, as well as the locomotor abilities of both female and male Drosophila melanogaster （t=9.970, 3.798, 8.994 and 10.451, P<0.01）. The results show that sodium cyclamate exhibit discernible effects on the reproduction, development, and locomotor abilities of Drosophila melanogaster. Caution should be exercised in their application in food production, and consumers should pay attention to the sweetener content for food safety considerations. [ABSTRACT FROM AUTHOR]

Successful completion of spermatogenesis is crucial for the perpetuation of the species. In Drosophila, spermatid individualization, a process involving changes in mitochondrial structure and function is critical to produce functional mature sperm. Ant2, encoding a mitochondrial adenine nucleotide translocase, is highly expressed in male testes and plays a role in energy metabolism in the mitochondria. However, its molecular function remains unclear. Here, we identified an important role of Ant2 in spermatid individualization. In Ant2 knockdown testes, spermatid individualization complexes composed of F‐actin cones exhibited a diffuse distribution, and mature sperms were absent in the seminal vesicle, thus leading to male sterility. The most striking effects in Ant2‐knockdown spermatids were decrease in tubulin polyglycylation and disruption of proper mitochondria derivatives function. Excessive apoptotic cells were also observed in Ant2‐knockdown testes. To further investigate the phenotype of Ant2 knockdown in testes at the molecular level, complementary transcriptome and proteome analyses were performed. At the mRNA level, 868 differentially expressed genes were identified, of which 229 genes were upregulated and 639 were downregulated induced via Ant2 knockdown. iTRAQ‐labeling proteome analysis revealed 350 differentially expressed proteins, of which 117 proteins were upregulated and 233 were downregulated. The expression of glutathione transferase (GstD5, GstE5, GstE8, and GstD3), proteins involved in reproduction were significantly regulated at both the mRNA and protein levels. These results indicate that Ant2 is crucial for spermatid maturation by affecting mitochondrial morphogenesis. [ABSTRACT FROM AUTHOR]

Phenylacetaldehyde (PAH), an aromatic compound, is present in a diverse range of fruits including overripe bananas and prickly pear cactus, the two major host fruits for Drosophila melanogaster. PAH acts as a potent ligand for the ionotropic receptor 84a (IR84a) in the adult fruit fly and it is detected by the IR84a/IR8a heterotetrameric complex. Its role in the male courtship behavior through IR84a as an environmental aphrodisiac is of additional importance. In D. melanogaster, two distinct kinds of olfactory receptors, that is, odorant receptors (ORs) and ionotropic receptors (IRs), perceive the odorant stimuli. They display unique structural, molecular, and functional characteristics in addition to having different evolutionary origins. Traditionally, olfactory cues detected by the ORs such as ethyl acetate, 1‐butanol, isoamyl acetate, 1‐octanol, 4‐methylcyclohexanol, etc. classified as aliphatic esters and alcohols have been employed in olfactory classical conditioning using fruit flies. This underlines the participation of OR‐activated olfactory pathways in learning and memory formation. Our study elucidates that likewise ethyl acetate (EA) (an OR‐responsive odorant), PAH (an IR‐responsive aromatic compound) too can form learning and memory when associated with an appetitive gustatory reinforcer. The association of PAH with sucrose (PAH/SUC) led to learning and formation of the long‐term memory (LTM). Additionally, the Orco1, Ir84aMI00501, and Ir8a1 mutant flies were used to confirm the exclusive participation of the IR84a/IR8a complex in PAH/SUC olfactory associative conditioning. These results highlight the involvement of IRs via an IR‐activated pathway in facilitating robust olfactory behavior. [ABSTRACT FROM AUTHOR]

In most species studied, energy deficits inhibit female reproductive behavior, but the location and nature of energy sensors and how they affect behavior are unknown. Progress has been facilitated by using Drosophila melanogaster, a species in which reproduction and food availability are closely linked. Adult males and females were either fed or food deprived (FD) and then tested in an arena with a fed, opposite-sex conspecific with no food in the testing arena. Only FD females (not FD males) significantly decreased their copulation rate and increased their copulation latency, and the effects of FD were prevented in females fed either yeast alone or glucose alone, but not sucralose alone, cholesterol alone, or amino acids alone. It is well-known that high-fat diets inhibit copulation rate in this species, and the effects of FD on copulation rate were mimicked by treatment with an inhibitor of glucose but not free fatty acid oxidation. The availability of oxidizable glucose was a necessary condition for copulation rate in females fed either yeast alone or fed a nutritive fly medium, which suggests that the critical component of yeast for female copulation rate is oxidizable glucose. Thus, female copulation rate in D. melanogaster is sensitive to the availability of oxidizable metabolic fuels, particularly the availability of oxidizable glucose or substrates/byproducts of glycolysis. NEW & NOTEWORTHY Copulation rate was decreased in food-deprived female but not in male adults when tested without food in the testing arena. Copulation rate was 1) maintained by feeding glucose alone, yeast alone, nutritive medium lacking yeast, but not sucralose, amino acids, or cholesterol alone; 2) decreased by inhibition of glycolysis in females fed either nutritive medium or yeast alone; and 3) not affected by inhibition of fatty acid oxidation. Thus, female copulation rate was linked to glycolytic status. [ABSTRACT FROM AUTHOR]

The larval stage of the Drosophila melanogaster life cycle is characterized by rapid growth and nutrient storage that occur over three instar stages separated by molts. In the third instar, the steroid hormone ecdysone drives key developmental processes and behaviors that occur in a temporally-controlled sequence and prepare the animal to undergo metamorphosis. Accurately staging Drosophila larvae within the final third instar is critical due to the rapid developmental progress at this stage, but it is challenging because the rate of development varies widely across a population of animals even if eggs are laid within a short period of time. Moreover, many methods to stage third instar larvae are cumbersome, and inherent variability in the rate of development confounds some of these approaches. Here we demonstrate the usefulness of the Sgs3-GFP transgene, a fusion of the Salivary gland secretion 3 (Sgs3) and GFP proteins, for staging third instar larvae. Sgs3-GFP is expressed in the salivary glands in an ecdysone-dependent manner from the midpoint of the third instar, and its expression pattern changes reproducibly as larvae progress through the third instar. We show that Sgs3-GFP can easily be incorporated into experiments, that it allows collection of developmentally-equivalent individuals from a mixed population of larvae, and that its use enables precise assessment of changing levels of hormones, metabolites, and gene expression during the second half of the third instar. [Display omitted] • Use of inaccurately-staged Drosophila third instar larvae introduces experimental error. • Inaccurate staging can impact assessment and discovery of mutant phenotypes. • Sgs3-GFP facilitates collection of developmentally-equivalent third instar larvae. • Sgs3-GFP is easy to use and allows fast visual staging of larvae. • Staging third instar larvae with Sgs3-GFP increases accuracy and reliability of data. [ABSTRACT FROM AUTHOR]

Drosophila melanogaster is an ideal model organism for investigating spermatogenesis due to its powerful genetics, conserved genes and visible morphology of germ cells during sperm production. Our previous work revealed that ocnus (ocn) knockdown resulted in male sterility, and CG9920 was identified as a significantly downregulated protein in fly abdomen after ocn knockdown, suggesting a role of CG9920 in male reproduction. In this study, we found that CG9920 was highly expressed in fly testes. CG9920 knockdown in fly testes caused male infertility with no mature sperms in seminal vesicles. Immunofluorescence staining showed that depletion of CG9920 resulted in scattered spermatid nuclear bundles, fewer elongation cones that did not migrate to the anterior region of the testis, and almost no individualization complexes. Transmission electron microscopy revealed that CG9920 knockdown severely disrupted mitochondrial morphogenesis during spermatogenesis. Notably, we found that CG9920 might not directly interact with Ocn, but rather was inhibited by STAT92E, which itself was indirectly affected by Ocn. We propose a possible novel pathway essential for spermatogenesis in D. melanogaster , whereby Ocn indirectly induces CG9920 expression, potentially counteracting its inhibition by the JAK-STAT signaling pathway. [Display omitted] • CG9920 knockdown in germline caused male sterility with no mature sperms. • Depletion of CG9920 resulted in scattered spermatid nuclear bundles. • CG9920 knockdown led to fewer elongation cones and almost no ICs. • CG9920 knockdown disrupted mitochondrial morphogenesis during spermatogenesis. • CG9920 might be regulated by Ocnus through the JAK-STAT pathway. [ABSTRACT FROM AUTHOR]

Current antidiabetic medications have a plethora of harmful side effects, and most of the drugs do not contain 1,3,4-oxadiazole moiety. Therefore, research into the development of novel drugs which contain 1,3,4-oxadiazole moiety with fewer side effects is necessary. Novel fluorine-incorporated 1,3,4-oxadiazole derivatives (1c–1n) were synthesized, characterized, and evaluated for α-amylase and α-glucosidase enzyme inhibitor activity. An in vivo Drosophila melanogaster model and an in vitro system were used to investigate its antidiabetic properties, further, which were characterized by 1HNMR, MASS, and FT-IR. Spectroscopic techniques and DFT are used to calculate more geometrically optimized molecule structures using the B3LYP technique. The compounds were tested against the α-glucosidase and α-amylase enzymes. Among different compounds tested, compounds 1i (IC50 = 54.83 µg/ml), 1k (IC50 = 64.95 µg/ml), 1m (IC50 = 64.78 µg/ml), and 1n (IC50 = 66.30 µg/ml) showed significant α-amylase inhibitor efficacy compared to the acarbose (IC50 = 35.17 µg/ml); compounds 1m (IC50 = 74.64 µg/ml) and 1i (IC50 = 60.35 µg/ml) exhibited significant α-glucosidase inhibitory action compared to acarbose (IC50 = 46.06 µg/ml). The docking study exhibited that compound 1i creates six hydrogen bonds and compound 1m forms three hydrogen bonding contacts at the active site of the enzyme (PDBID:4w93). The obtained results are demonstrated that compounds 1i, 1m, 1n, and 1k had greater antidiabetic activities and can be further taken into consideration for antidiabetic therapeutic interventions. [ABSTRACT FROM AUTHOR]

This paper reevaluates the first report of X-ray-induced somatic gene mutations. It was undertaken by John Patterson, Department Chair of Hermann Muller, using the same biological model, methods and equipment of Muller. Patterson reported X-ray induced mutation frequencies for X-chromosome-linked (sex-linked) recessive gene mutations in somatic cells of Drosophila melanogaster that resulted in color changes in the ommatidia of the eyes. Results were based on color changes detected in both male and female offspring irradiated while in egg, larval or pupal stages and for unirradiated controls. Patterson claimed that the observed dose response displayed linearity, with a clear implication that the linear response extended to background exposure levels of unirradiated controls. This reanalysis disputes Patterson's interpretation, showing that the dose response in the low-dose zone strongly supported a threshold model. The doses in the experiment, which were not clearly presented, were so high that it would preclude the assumption that the experiment provided any information of relevance to radiation exposures of humans at low doses, or even at high doses delivered at low-dose rates. Induced phenotypical changes that occurred at the higher doses, especially in female offspring, overwhelmingly resulted from X-ray-induced chromosome breaks instead of point mutations as initially expected by Patterson. The Patterson findings and linearity interpretations were an important contributory factor in the acceptance of the linear non-threshold (LNT) model during the formative time of concept consolidation. It is rather shocking now to see that the actual data provided no support for the LNT model. [ABSTRACT FROM AUTHOR]

Simple Summary: Zelus renardii Kolenati (Hemiptera, Reduviidae, Harpactorinae), the Leafhopper Assassin Bug (LAB), first appeared in Europe in 2011 and is now well-acclimatized. The LAB is a promising mass-rearing candidate for the inundative biocontrol strategy of Xylella fastidiosa pauca ST53 vectors. We reared LABs for two subsequent years, using live adult Drosophila melanogaster Meigen (Diptera, Drosophilidae) (Dm) as living prey versus several artificial diet formulations (D0, D1, D2, D3, and D4), to identify the best formulation. An artificial medium can minimize rearing costs and make the process sustainable and safer. The rearing of LAB is feasible with live prey, oligidic, meridic, and holidic artificial formulations. All diets, except for D2, showed a favorable trend according to the species' reproductive potential. Scoring accumulated degree days in LAB's rearing made it possible to predict the time required to complete post-embryonic development as a function of temperature. Mass production is a prerequisite for using natural enemies in integrated pest management and organic farming. Natural enemies in agroecosystems include predators that prey on insects, which they can subdue while maintaining adequate pest population densities. The Leafhopper Assassin Bug (LAB), Zelus renardii, can be a natural enemy in agroecosystems, selecting its prey for size and mobility. Some of LAB's prey include Philaenus spumarius (L.), Bactrocera oleae (Rossi), Drosophila suzukii (Matsumura), and Macrohomotoma gladiata Kuwayama, suggesting this reduviid for biocontrol agent in various contexts. We reared LABs for two subsequent broods offering living prey and artificial diets. Our data show that the rearing of Z. renardii is feasible with oligidic, meridic, and holidic artificial formulations. Four artificial diets allowed the complete post-embryonic development of LABs in captivity for two successive generations. The accumulated degree-days (ADDs) accurately predict the growth of LABs based on heat accumulation, estimating that up to three generations could grow per year in captivity at the experimented T°C. [ABSTRACT FROM AUTHOR]

Sexes often have differing fitness optima, potentially generating intra-locus sexual conflict, as each sex bears a genetic "load" of alleles beneficial to the other sex. One strategy to evaluate conflict in the genome is to artificially select populations discordantly against established sexual dimorphism (SD), reintroducing attenuated conflict. We investigate a long-term artificial selection experiment reversing sexual size dimorphism in Drosophila melanogaster during ~350 generations of sexually discordant selection. We explore morphological and genomic changes to identify loci under selection between the sexes in discordantly and concordantly size-selected treatments. Despite substantial changes to overall size, concordant selection maintained ancestral SD. However, discordant selection altered size dimorphism in a trait-specific manner. We observe multiple possible soft selective sweeps in the genome, with size-related genes showing signs of selection. Patterns of genomic differentiation between the sexes within lineages identified potential sites maintained by sexual conflict. One discordant selected lineage shows a pattern of elevated genomic differentiation between males and females on chromosome 3L, consistent with the maintenance of sexual conflict. Our results suggest visible signs of conflict and differentially segregating alleles between the sexes due to discordant selection. [ABSTRACT FROM AUTHOR]

Transvection is a phenomenon of interallelic communication in which enhancers can activate a specific promoter located on a homologous chromosome. Insulators play a significant role in ensuring functional interactions between enhancers and promoters. In the presented work, we created a model where two or three copies of the insulator are located next to enhancers and promoters localized on homologous chromosomes. Using the Su(Hw) insulator as a model, we showed that the functional interaction between a pair of insulators promotes enhancer–promoter trans-interactions. The interaction between the three insulators, on the contrary, can lead to the formation of chromatin loops that sterically hinder the full enhancer–promoter interaction. The results of the work suggest the participation of insulators in the regulation of homologous chromosome pairing and in communication between distant genomic loci. [ABSTRACT FROM AUTHOR]

Cryptochromes (Crys) represent a multi-facetted class of proteins closely associated with circadian clocks. They have been shown to function as photoreceptors but also to fulfill light-independent roles as transcriptional repressors within the negative feedback loop of the circadian clock. In addition, there is evidence for Crys being involved in light-dependent magneto-sensing, and regulation of neuronal activity in insects, adding to the functional diversity of this cryptic protein class. In mammals, Crys are essential components of the circadian clock, but their role in other vertebrates is less clear. In invertebrates, Crys can function as circadian photoreceptors, or as components of the circadian clock, while in some species, both light-receptive and clock factor roles coexist. In the current study, we investigate the function of Cry proteins in zebrafish (Danio rerio), a freshwater teleost expressing 6 cry genes. Zebrafish peripheral circadian clocks are intrinsically light-sensitive, suggesting the involvement of Cry in light-resetting. Echinoderms (Strongylocentrotus purpuratus) represent the only class of deuterostomes that possess an orthologue (SpuCry) of the light-sensitive Drosophila melanogaster Cry, which is an important component of the light-resetting pathway, but also works as transcriptional repressor in peripheral clocks of fruit flies. We therefore investigated the potential of different zebrafish cry genes and SpuCry to replace the light-resetting and repressor functions of Drosophila Cry by expressing them in fruit flies lacking endogenous cry function. Using various behavioral and molecular approaches, we show that most Cry proteins analyzed are able to fulfill circadian repressor functions in flies, except for one of the zebrafish Crys, encoded by cry4a. Cry4a also shows a tendency to support light-dependent Cry functions, indicating that it might act in the light-input pathway of zebrafish. [ABSTRACT FROM AUTHOR]

Adjustment of the cellular metabolism of pro‐inflammatory macrophages is essential for their bactericidal function; however, it underlies the development of many human diseases if induced chronically. Therefore, intervention of macrophage metabolic polarisation has been recognised as a potent strategy for their treatment. Although many small‐molecule inhibitors affecting macrophage metabolism have been identified, their in vivo administration requires a tool for macrophage‐specific delivery to limit their potential side effects. Here, we establish Drosophila melanogaster as a simple experimental model for in vivo testing of macrophage‐specific delivery tools. We found that yeast‐derived glucan particles (GPs) are suitable for macrophage‐specific delivery of small‐molecule inhibitors. Systemic administration of GPs loaded with atorvastatin, the inhibitor of hydroxy‐methyl‐glutaryl‐CoA reductase (Hmgcr), leads to intervention of mevalonate pathway specifically in macrophages, without affecting HMGCR activity in other tissues. Using this tool, we demonstrate that mevalonate pathway is essential for macrophage pro‐inflammatory polarisation and individual's survival of infection. [ABSTRACT FROM AUTHOR]

Animals can adjust their consumption of different nutrients to adaptively match their current or expected physiological state. Changes in diet preference can arise from social and sexual experience. For example, in female Drosophila melanogaster fruit flies, a single mating triggers a behavioural switch in diet choice towards increased protein intake and total food consumption, which supports offspring production. In contrast, male diet choice appears to be unaffected by a single mating. However, one mating may not fully capture the impact of mating on male feeding behaviour. Males can often mate multiply in natural settings, and the costs of ejaculate production and energetic courtship may be cumulative, such that males might experience increased nutritional demands only after multiple matings. In this study we tested this prediction by measuring the effect of multiple matings on the diet choice of male D. melanogaster fruit flies. Males were assigned to one of three mating treatments, unmated, mated once or mated five times consecutively, and then allowed to feed freely on chemically defined diets of protein and carbohydrate. In contrast to the prediction, we found that males that mated five times did not alter the amount of food, or the proportion of protein and carbohydrate consumed, when compared with unmated or once-mated males. This absence of a feeding response occurred despite substantial ejaculate depletion from multiple matings: males sired fewer offspring in each consecutive mating. These results reveal a lack of plasticity in male feeding behaviour according to mating status, despite substantial potential physiological costs, and highlight the remarkably distinct nutritional ecologies of males versus females. • Female fruit flies show altered diet preference following mating. • However, dietary responses to mating in males are largely unknown. • We tested the impact of realistic mating rates on male fruit fly diet choice. • Males do not alter food intake to recoup depleted ejaculate, despite fertility loss. • These results highlight key sex differences in diet choice following mating. [ABSTRACT FROM AUTHOR]

The functions of the heat shock protein 70 (Hsp70) genes were studied using a line of Drosophila melanogaster with a knockout of 6 of these genes out of 13. Namely, the effect of knockout of Hsp70 genes on negative geotaxis climbing (locomotor) speed and the ability to adapt to climbing training (0.5–1.5 h/day, 7 days/wk, 19 days) were examined. Seven- and 23-day-old Hsp70− flies demonstrated a comparable reduction (twofold) in locomotor speed and widespread changes in leg skeletal muscle transcriptome (RNA sequencing) compared with w1118 flies. To identify the functions of genes related to decreased locomotor speed, the overlapped differentially expressed genes at both time points were analyzed: the upregulated genes encoded extracellular proteins, regulators of drug metabolism, and the antioxidant response, whereas downregulated genes encoded regulators of carbohydrate metabolism and transmembrane proteins. In addition, in Hsp70− flies, activation of transcription factors related to disruption of the fibril structure and heat shock response (Hsf) was predicted, using the position weight matrix approach. In control flies, adaptation to chronic exercise training was associated mainly with gene response to a single exercise bout, whereas the predicted transcription factors were related to stress/immune (Hsf, NF-κB, etc.) and early gene response. In contrast, Hsp70− flies demonstrated no adaptation to training as well as a significantly impaired gene response to a single exercise bout. In conclusion, the knockout of Hsp70 genes not only reduced physical performance but also disrupted adaptation to chronic physical training, which is associated with changes in the leg skeletal muscle transcriptome and impaired gene response to a single exercise bout. NEW & NOTEWORTHY: Knockout of six heat shock protein 70 (Hsp70) genes in Drosophila melanogaster reduced locomotion (climbing) speed that is associated with genotype-specific differences in leg skeletal muscle gene expression. Disrupted adaptation of Hsp70− flies to chronic exercise training is associated with impaired gene response to a single exercise bout. [ABSTRACT FROM AUTHOR]

The extraction and composition analysis of peptides (FNPs) from fermentation Nannochloropsis sp., as well as their anti-aging effects on Drosophila melanogaster in vivo were investigated. Compared with the non-fermentation group, the number of peptide in FNPs increases by about 100, and the oxidation sites in the peptides also increase. The maximum absorption intensity of FNPs is observed at 258 nm with a dose-dependent relationship. Compared with the control group, 5 μg/mL FNPs extends the mean life span of the the natural aging Drosophila melanogaster for 13 days. Additionally, for 70-90 days old, the deterioration of oxidative stress indicators such as MDA, SOD, and CAT caused by age are significantly restored and increased to the level of positive group by FNPs at 0.5 and 5 μg/mL. These results indicate that FNPs have potential as a promising nutritional component for alleviating human health problems induced by aging. It can also be used as a new antioxidant ingredient for functional food development or cosmeceutical applications from a resource rich and easily obtainable raw material Nannochloropsis sp. [ABSTRACT FROM AUTHOR]

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Diet and health are strongly linked, though the strict changes in diet required to improve health outcomes are usually difficult to sustain. We sought to understand whether short-term bouts of amino acid–specific modifications to the diet of Drosophila melanogaster could mimic the lifespan and stress resistance benefits of dietary restriction, without the requirement for drastic reductions in food intake. We found that flies that were transiently fed diets lacking the essential amino acid isoleucine, but otherwise nutritionally complete, exhibited enhanced nicotine tolerance, indicating elevated detoxification capacity. The protection from isoleucine deprivation increased with the duration of exposure, up to a maximum at 7-day isoleucine deprivation for flies 2, 3, or 4 weeks of age, and a 5-day deprivation when flies were 5 weeks of age. Because of these beneficial effects on toxin resistance, we intermittently deprived flies of isoleucine during the first 6 weeks of adulthood and monitored the effect on lifespan. Lifespan was significantly extended when flies experienced short-term isoleucine deprivation at 3 and 5 weeks of age, regardless of whether they were also deprived at 1 week. These results indicate that short-term bouts of isoleucine deprivation can extend lifespan and highlight its cumulative and time-dependent benefits. Interestingly, we found that isoleucine-deprived flies lost their protection against nicotine within 3 days of returning to fully fed conditions. Therefore, the mechanisms underlying lifespan extension may involve transient damage clearance during the bouts of isoleucine deprivation rather than sustained enhanced detoxification capacity. These data highlight a new time-restricted, nutritionally precise method to extend life in Drosophila melanogaster and point to a more manageable dietary method to combat ageing. [ABSTRACT FROM AUTHOR]

When replication forks encounter damaged DNA, cells utilize damage tolerance mechanisms to allow replication to proceed. These include translesion synthesis at the fork, postreplication gap filling, and template switching via fork reversal or homologous recombination. The extent to which these different damage tolerance mechanisms are utilized depends on cell, tissue, and developmental context-specific cues, the last two of which are poorly understood. To address this gap, we have investigated damage tolerance responses in Drosophila melanogaster. We report that tolerance of DNA alkylation damage in rapidly dividing larval tissues depends heavily on translesion synthesis. Furthermore, we show that the REV1 protein plays a multi-faceted role in damage tolerance in Drosophila. Larvae lacking REV1 are hypersensitive to methyl methanesulfonate (MMS) and have highly elevated levels of γ-H2Av (Drosophila γ-H2AX) foci and chromosome aberrations in MMS-treated tissues. Loss of the REV1 C-terminal domain (CTD), which recruits multiple translesion polymerases to damage sites, sensitizes flies to MMS. In the absence of the REV1 CTD, DNA polymerases eta and zeta become critical for MMS tolerance. In addition, flies lacking REV3, the catalytic subunit of polymerase zeta, require the deoxycytidyl transferase activity of REV1 to tolerate MMS. Together, our results demonstrate that Drosophila prioritize the use of multiple translesion polymerases to tolerate alkylation damage and highlight the critical role of REV1 in the coordination of this response to prevent genome instability. Author summary: Organisms have evolved several ways to continue copying their DNA when it is damaged, grouped into the categories of translesion synthesis and template switching. These damage tolerance mechanisms prevent replication forks from collapsing when they encounter DNA damage and prevent catastrophic genome instability and cell death. While the proteins and pathways involved in damage tolerance are beginning to be understood at the single cell level, how they are regulated in multicellular organisms remains an intriguing question. In this study, we investigated the mechanisms by which Drosophila tolerate alkylation damage. We discovered that tissues containing rapidly dividing diploid cells favor translesion synthesis over recombination-based mechanisms of damage tolerance, preferentially utilizing different translesion polymerases in a context-dependent manner. Furthermore, we showed that the REV1 protein, best known for its role in recruiting translesion DNA polymerases to damage sites, performs multiple functions during damage tolerance. Together, our results demonstrate that damage tolerance preferences for multicellular organisms may differ from those observed in cultured cells and establish Drosophila as a useful model system for studying tolerance mechanisms. [ABSTRACT FROM AUTHOR]

Mating experience impacts the physiology and behavior of animals. Although mating effects of female Drosophila melanogaster have been studied extensively, the behavioral changes of males following copulation have not been fully understood. In this study, we characterized the mating-dependent behavioral changes of male flies, especially focusing on fly-to-fly interaction, and their dependence on rearing conditions. Our data demonstrate that male flies quiesce their courtship toward both females and males, as well as their locomotor activity. This post-copulatory quiescence appears to be contingent upon the presence of a peer, as minimal variation is noted in locomotion when the male is measured in isolation. Interestingly, copulated males influence a paired male without successful copulation to reduce his locomotion. Our findings point to a conditional behavioral quiescence following copulation, influenced by the presence of other flies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cph is the Drosophila homologue of BCL11A (CTIP1) and BCL11B (CTIP2) • Cph knockdown results in crawling disabilities in larvae. • Cph knockdown flies show loss of co-ordination and motor activity. • Evoked signalling is reduced and irregular in these animals. • Cph expressing neurons are glutamatergic. Functioning of the nervous system requires proper formation and specification of neurons as well as accurate connectivity and signalling between them. Locomotor behaviour depends upon these events that occur during neural development, and any aberration in them could result in motor disorders. Transcription factors are believed to be master regulators that control these processes, but very few linked to behaviour have been identified so far. The Drosophila homologue of BCL11A (CTIP1) and BCL11B (CTIP2), Chronophage (Cph), was recently shown to be involved in temporal patterning of neural stem cells but its role in post-mitotic neurons is not known. We show that knockdown of Cph in neurons during development results in animals with locomotor defects at both larval and adult stages. The defects are more severe in adults, with inability to stand, uncoordinated behaviour and complete loss of ability to walk, climb, or fly. These defects are similar to the motor difficulties observed in some patients with mutations in BCL11A and BCL11B. Electrophysiological recordings showed reduced evoked activity and irregular neuronal firing. All Cph -expressing neurons in the ventral nerve cord are glutamatergic. Our results imply that Cph modulates primary locomotor activity through configuration of glutamatergic neurons. Thus, this study ascribes a hitherto unknown role to Cph in locomotor behaviour of Drosophila melanogaster. [ABSTRACT FROM AUTHOR]

The intracellular symbiont Wolbachia pipientis evolved after the divergence of arthropods and nematodes, but it reached high prevalence in many of these taxa through its abilities to infect new hosts and their germlines. Some strains exhibit long-term patterns of co-evolution with their hosts, while other strains are capable of switching hosts. This makes strain selection an important factor in symbiont-based biological control. However, little is known about the ecological and evolutionary interactions that occur when a promiscuous strain colonizes an infected host. Here, we study what occurs when two strains come into contact in host cells following horizontal transmission and infection. We focus on the faithful wMel strain from Drosophila melanogaster and the promiscuous wRi strain from Drosophila simulans using an in vitro cell culture system with multiple host cell types and combinatorial infection states. Mixing D. melanogaster cell lines stably infected with wMel and wRi revealed that wMel outcompetes wRi quickly and reproducibly. Furthermore, wMel was able to competitively exclude wRi even from minuscule starting quantities, indicating that this is a nearly deterministic outcome, independent of the starting infection frequency. This competitive advantage was not exclusive to wMel's native D. melanogaster cell background, as wMel also outgrew wRi in D. simulans cells. Overall, wRi is less adept at in vitro growth and survival than wMel and its in vivo state, revealing differences between the two strains in cellular and humoral regulation. These attributes may underlie the observed low rate of mixed infections in nature and the relatively rare rate of host-switching in most strains. Our in vitro experimental framework for estimating cellular growth dynamics of Wolbachia strains in different host species, and cell types provides the first strategy for parameterizing endosymbiont and host cell biology at high resolution. This toolset will be crucial to our application of these bacteria as biological control agents in novel hosts and ecosystems. Author summary: Wolbachia pipientis is one of the most common bacterial endosymbionts due to its ability to manipulate host reproduction, and it has become a useful biological control tool for mosquito populations. Wolbachia is passed from mother to offspring, however the bacterium can also "jump" to new hosts via horizontal transmission. When a Wolbachia strain successfully infects a new host, it may encounter a resident strain, possibly resulting in a superinfection of both strains, or replacement of the resident strain by the new strain. Here, we use a Drosophila melanogaster cell culture system to study the dynamics of mixed Wolbachia infections consisting of the high-fidelity wMel and promiscuous wRi strains. The wMel strain consistently outcompetes the wRi strain, regardless of wMel's initial frequency in D. melanogaster cells. This competitive advantage is independent of host species. While both strains significantly impede host cell division, only the wMel strain is able to rapidly expand into uninfected cells. Our results suggest that the wRi strain is pathogenic in nature and a poor cellular symbiont, and it is retained in natural infections because cell lineages are not expendable or replaceable in development. These findings provide insights into mixed infection outcomes, which are crucial for the use of the bacteria in biological control. [ABSTRACT FROM AUTHOR]

The fungal pathogen Batrachochytrium dendrobatidis (Bd) causes the disease amphibian chytridiomycosis, which has contributed to population declines in many species of amphibians throughout the world. Previous observational studies have shown that nematodes, waterfowl, lizards, other dipterans, and crayfish have properties which may allow them to harbor and spread Bd; therefore, we sought to determine the carrier capabilities of invertebrates to a further extent in a laboratory setting. We use the insect Drosophila melanogaster as a model organism to quantify the potential relationship between insects and Bd. Our findings show that D. melanogaster can test positive for Bd for up to five days post-exposure and can transmit Bd to conspecifics without suffering mortality. Insects of various types interact with the amphibian habitat and amphibians themselves, making this a potentially important route of transmission between amphibians and of dispersal across the environment. [ABSTRACT FROM AUTHOR]

During locomotion, soft-bodied terrestrial animals solve complex control problems at substrate interfaces, but our understanding of how they achieve this without rigid components remains incomplete. Here, we develop new all-optical methods based on optical interference in a deformable substrate to measure ground reaction forces (GRFs) with micrometre and nanonewton precision in behaving Drosophila larvae. Combining this with a kinematic analysis of substrate-interfacing features, we shed new light onto the biomechanical control of larval locomotion. Crawling in larvae measuring ~1 mm in length involves an intricate pattern of cuticle sequestration and planting, producing GRFs of 1–7 µN. We show that larvae insert and expand denticulated, feet-like structures into substrates as they move, a process not previously observed in soft-bodied animals. These ‘protopodia’ form dynamic anchors to compensate counteracting forces. Our work provides a framework for future biomechanics research in soft-bodied animals and promises to inspire improved soft-robot design. [ABSTRACT FROM AUTHOR]

Thermoregulation is a fundamental mechanism for maintaining homeostasis in living organisms because temperature affects essentially all biochemical and physiological processes. Effector responses to internal and external temperature cues are critical for achieving effective thermoregulation by controlling heat production and dissipation. Thermoregulation can be classified as physiological, which is observed primarily in higher organisms (homeotherms), and behavioral, which manifests as crucial physiological functions that are conserved across many species. Neuronal pathways for physiological thermoregulation are wellcharacterized, but those associated with behavioral regulation remain unclear. Thermoreceptors, including Transient Receptor Potential (TRP) channels, play pivotal roles in thermoregulation. Mammals have 11 thermosensitive TRP channels, the functions for which have been elucidated through behavioral studies using knockout mice. Behavioral thermoregulation is also observed in ectotherms such as the fruit fly, Drosophila melanogaster. Studies of Drosophila thermoregulation helped elucidate significant roles for thermoreceptors as well as regulatory actions of membrane lipids in modulating the activity of both thermosensitive TRP channels and thermoregulation. This review provides an overview of thermosensitive TRP channel functions in behavioral thermoregulation based on results of studies involving mice or Drosophila melanogaster. [ABSTRACT FROM AUTHOR]

Introduction: Centella asiatica (CA) is known in Ayurvedic medicine as a rejuvenating herb with particular benefits in the nervous system. Two groups of specialized metabolites found in CA and purported to contribute to its beneficial effects are triterpenes (TTs) and caffeoylquinic acids (CQAs). In order to evaluate the role and interactions of TTs and CQAs in the effects of CA, we examined the neurotrophic effects of a water extract of CA (CAW) and combinations of its TT and CQA components in mouse primary hippocampal neurons in vitro and in Drosophila melanogaster flies in vivo. Methods: Primary hippocampal neurons were isolated from mouse embryos and exposed in vitro for 5 days toCAW(50 µg/mL), mixtures of TTs, CQAs or TT +CQA components or to 4 TTs or 8 individual CQA compounds of CAW. Dendritic arborization was evaluated using Sholl analysis. Drosophila flies were aged to 28 days and treated for 2 weeks with CAW (10 mg/mL) in the food, mixtures of TTs, CQAs or TT + CQA and individual TT and CQA compounds. TTs and CQAs were tested at concentrations matching their levels in the CAW treatment used. After 2 weeks of treatment, Drosophila aged 42 days were evaluated for phototaxis responses. Results: In mouse primary hippocampal neurons, CAW (50 µg/mL), the TT mix, CQA mix, all individual TTs and most CQAs significantly increased dendritic arborization to greater than control levels. However, the TT + CQA combination significantly decreased dendritic arborization. In Drosophila, a marked age-related decline in fast phototaxis response was observed in both males and females over a 60 days period. However, resilience to this decline was afforded in both male and female flies by treatment from 28 days onwards with CAW (10 mg/mL), or equivalent concentrations of mixed TTs, mixed CQAs and a TT + CQA mix. Of all the individual compounds, only 1,5-diCQA slowed age-related decline in phototaxis in male and female flies. Discussion: This study confirmed the ability of CAW to increase mouse neuronal dendritic arborization, and to provide resilience to age-related neurological decline in Drosophila. The TT and CQA components both contribute to these effects but do not have a synergistic effect. While individual TTs and most individual CQAs increased dendritic arborization at CAW equivalent concentrations, in the Drosophila model, only 1,5-diCQA was able to slow down the age-related decline in phototaxis. This suggests that combinations (or potentially higher concentrations) of the other compounds are needed to provide resilience in this model. [ABSTRACT FROM AUTHOR]

Since the discovery of the genetic origin of the circadian clock in Drosophila melanogaster by Konopka and Benzer in 1971, most of the research about the regulation of the molecular circadian clock relies on laboratory models. Additional models such as Cyanobacteria, Neurospora crassa, Arabidopsis and rodents helped chronobiologists to describe the species‐specific molecular clocks and their regulation. However, the lack of tools and the difficulty to access biological samples somehow excluded human from this research landscape outside behavioural research. Among many other impressive achievements, Steve Brown provided to the community of chronobiologists new tools and strategies to study the individual human circadian clock and its regulation. [ABSTRACT FROM AUTHOR]

HemK2 is a highly conserved methyltransferase, but the identification of its genuine substrates has been controversial, and its biological importance in higher organisms remains unclear. We elucidate the role of HemK2 in the methylation of eukaryotic Release Factor 1 (eRF1), a process that is essential for female germline development in Drosophila melanogaster. Knockdown of hemK2 in the germline cells (hemK2-GLKD) induces apoptosis, accompanied by a pronounced decrease in both eRF1 methylation and protein synthesis. Overexpression of a methylation-deficient eRF1 variant recapitulates the defects observed in hemK2-GLKD, suggesting that eRF1 is a primary methylation target of HemK2. Furthermore, hemK2-GLKD leads to a significant reduction in mRNA levels in germline cell. These defects in oogenesis and protein synthesis can be partially restored by inhibiting the No-Go Decay pathway. In addition, hemK2 knockdown is associated with increased disome formation, suggesting that disruptions in eRF1 methylation may provoke ribosomal stalling, which subsequently activates translationcoupled mRNA surveillance mechanisms that degrade actively translated mRNAs. We propose that HemK2-mediated methylation of eRF1 is crucial for ensuring efficient protein production and mRNA stability, which are vital for the generation of high-quality eggs. [ABSTRACT FROM AUTHOR]

Serine proteases are important regulators of airway epithelial homeostasis. Altered serum or cellular levels of two serpins, Scca1 and Spink5, have been described for airway diseases but their function beyond antiproteolytic activity is insufficiently understood. To close this gap, we generated fly lines with overexpression or knockdown for each gene in the airways. Overexpression of both fly homologues of Scca1 and Spink5 induced the growth of additional airway branches, with more variable results for the respective knockdowns. Dysregulation of Scca1 resulted in a general delay in fruit fly development, with increases in larval and pupal mortality following overexpression of this gene. In addition, the morphological changes in the airways were concomitant with lower tolerance to hypoxia. In conclusion, the observed structural changes of the airways evidently had a strong impact on the airway function in our model as they manifested in a lower physical fitness of the animals. We assume that this is due to insufficient tissue oxygenation. Future work will be directed at the identification of key molecular regulators following the airway-specific dysregulation of Scca1 and Spink5 expression. [ABSTRACT FROM AUTHOR]

Mate choice is a crucial decision in any animal. In terms of fitness, the best mate is the one that leads to the most abundant and productive offspring. Pairing with a low-quality mate would reduce fitness, generating selection for accurate and subtle mate choice in all animal species. Hence, mate choice is expected to be highly context dependent, and should depend on other potential options. For instance, a medium-quality male can constitute the best option when all other males are in poorer condition, but not when there are better-quality males available. Therefore, animals are predicted to gather information about their social context and adapt their mate choice to it. Here, we report on experiments in which we manipulated the social environment of females of Drosophila melanogaster and found that after encountering a high or a low-quality male, they take more or less time to accept copulation with another male, suggesting that females adapt their mating strategy to their social context. We also report on a similar effect in D. biarmiceps. Thus, male attractiveness appears to depend on the quality of recently met males, suggesting that male attractiveness is subjective, indicating plastic and context dependent mate choice. [ABSTRACT FROM AUTHOR]

Many environmental features are cyclic, with predictable changes across the day, seasons and latitudes. Additionally, anthropogenic, artificial-light-induced changes in photoperiod or shiftwork-driven novel light/dark cycles also occur. Endogenous timekeepers or circadian clocks help organisms cope with such changes. The remarkable plasticity of clocks is evident in the waveforms of behavioural and molecular rhythms they govern. Despite detailed mechanistic insights into the functioning of the circadian clock, practical means to manipulate activity waveform are lacking. Previous studies using a nocturnal rodent model showed that novel light regimes caused locomotor activity to bifurcate such that mice showed two bouts of activity restricted to the dimly lit phases. Here, we explore the generalizability of these findings and leverage the genetic toolkit of Drosophila melanogaster to obtain mechanistic insights into this unique phenomenon. We find that dim scotopic illumination of specific durations induces circadian photoreceptor CRYPTOCHROME-dependent activity bifurcation in male flies. We show circadian reorganization of the pacemaker circuit, wherein the 'evening' neurons regulate the timing of both bouts of activity under novel light regimes. Our findings indicate that such environmental regimes can be exploited to design light cycles, which can ease the circadian waveform into synchronizing with challenging conditions. [ABSTRACT FROM AUTHOR]

Despite impressive advances in the broad field of innate immunity, our understanding of the molecules and signaling pathways that control the host immune response to nematode infection remains incomplete. We have shown recently that Transforming Growth Factor-β (TGF-β) signaling in the fruit fly Drosophila melanogaster is activated by nematode infection and certain TGF-β superfamily members regulate the D. melanogaster anti-nematode immune response. Here, we investigate the effect of an entomopathogenic nematode infection factor on host TGF-β pathway regulation and immune function. We find that Heterorhabditis bacteriophora serine carboxypeptidase activates the Activin branch in D. melanogaster adults and the immune deficiency pathway in Activin-deficient flies, it affects hemocyte numbers and survival in flies deficient for Activin signaling, and causes increased intestinal steatosis in Activin-deficient flies. Thus, insights into the D. melanogaster signaling pathways and metabolic processes interacting with H. bacteriophora pathogenicity factors will be applicable to entomopathogenic nematode infection of important agricultural insect pests and vectors of disease. [ABSTRACT FROM AUTHOR]

Today, plastic pollution is one of the biggest threats to the environment and public health. In the tissues of exposed species, micro- and nano-fragments accumulate, leading to genotoxicity, altered metabolism, and decreased lifespan. A model to investigate the genotoxic and tumor-promoting potential of nanoplastics (NPs) is Drosophila melanogaster. Here we tested polystyrene, which is commonly used in food packaging, is not well recycled, and makes up at least 30% of landfills. In order to investigate the biological effects and carcinogenic potential of 100 µm polystyrene nanoparticles (PSNPs), we raised Oregon [R] wild-type flies on contaminated food. After prolonged exposure, fluorescent PSNPs accumulated in the gut and fat bodies. Furthermore, PSNP-fed flies showed considerable alterations in weight, developmental time, and lifespan, as well as a compromised ability to recover from starvation. Additionally, we noticed a decrease in motor activity in DNAlig4 mutants fed with PSNPs, which are known to be susceptible to dietary stressors. A qPCR molecular investigation of the larval intestines revealed a markedly elevated expression of the genes drice and p53, suggesting a response to cell damage. Lastly, we used warts-defective mutants to assess the carcinogenic potential of PSNPs and discovered that exposed flies had more aberrant masses than untreated ones. In summary, our findings support the notion that ingested nanopolystyrene triggers metabolic and genetic modifications in the exposed organisms, eventually delaying development and accelerating death and disease. [ABSTRACT FROM AUTHOR]

Fragile X syndrome (FXS) is caused by the full mutation in the FMR1 gene on the Xq27.3 chromosome region. It is the most common monogenic cause of autism spectrum disorder (ASD) and inherited intellectual disability (ID). Besides ASD and ID and other symptoms, individuals with FXS may exhibit sleep problems and impairment of circadian rhythm (CR). The Drosophila melanogaster models of FXS, such as dFMR1B55, represent excellent models for research in the FXS field. During this study, sleep patterns and CR in dFMR1B55 mutants were analyzed, using a new platform based on continuous high-resolution videography integrated with a highly-customized version of an open-source software. This methodology provides more sensitive results, which could be crucial for all further research in this model of fruit flies. The study revealed that dFMR1B55 male mutants sleep more and can be considered weak rhythmic flies rather than totally arrhythmic and present a good alternative animal model of genetic disorder, which includes impairment of CR and sleep behavior. The combination of affordable videography and software used in the current study is a significant improvement over previous methods and will enable broader adaptation of such high-resolution behavior monitoring methods. [ABSTRACT FROM AUTHOR]

Studies on numerous species have demonstrated strikingly conserved mechanisms that determine the aging process, from yeasts to worms, flies, zebrafish, mice, and humans. The fruit fly Drosophila melanogaster is an excellent model organism for studying the biological basis of normal aging and etiology of age-related diseases. Since its inception in 1967, the Bloomington Drosophila Stock Center (BDSC) has grown into the largest collection of documented D. melanogaster strains (currently > 91,000). This paper aims to briefly review conserved mechanisms of aging and provides a guide to help users understand the organization of stock listings on the BDSC website and familiarize themselves with the search functions on BDSC and FlyBase, with an emphasis on using genes in conserved pathways as examples to find stocks for aging studies. [ABSTRACT FROM AUTHOR]

Oxidative stress is proposed as a regulatory element in various neurological disorders, which is involved in the progress of several neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Antioxidant drugs are widely used to alleviate neurodegenerative disorders. Astragalus membranaceus (Huangqi, AM) is a commonly used medicinal herb with a wide range of pharmacological effects. Here, the protective effect and mechanism of AM extract (AME) and its bioactive compounds against neurodegenerative disorders via alleviating oxidative stress were detected using adult Drosophila melanogaster. The drug safety was measured by development analysis; oxidative stress resistance ability was detected by survival rate under H2O2 environment; ROS level was detected by DHE staining and gstD1‐GFP fluoresence assay; antioxidative abilitiy was represent by measuring antioxidant enzyme activity, antioxidative‐related gene expression, and ATP and MFN2 levels. The neuroprotective effect was evaluated by lifespan and locomotion analysis in Aβ42 transgenic and Pink1B9 mutants. AME dramatically increased the survival rates, improved the CAT activity, restored the decreased mRNA expressions of Sod1, Cat, and CncC under H2O2 stimulation, and ameliorated the neurobehavioral defects of the AD and PD. Thirteen small molecules in AM had antioxidant function, in which vanillic acid and daidzein had the most potent antioxidant effect. Vanillic acid and daidzein could increase the activities of SOD and CAT, GSH level, and the expressions of antioxidant genes. Vanillic acid could improve the levels of ATP and MFN2, and mRNA expressions of ND42 and SDHC to rescue mitochondrial dysfunction. Furthermore, vanillic acid ameliorated neurobehavioral defects of PD. Daidzein ameliorated neurobehavioral defect of Aβ‐induced AD mode. Taken together, AM plays a protective role in oxidative damage, thereby as a potential natural drug to treat neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

The present study reports highly stable polymeric nanoparticles comprising curcumin and polyvinylpyrrolidone, and then conjugated with gold nanoparticles, resulting in C-PVP and C-PVP-Au, respectively. The synthesized conjugates C-PVP and C-PVP-Au were investigated for amyloid aggregation inhibition activity, antimicrobial activity, and wound healing applications. The anti-amyloidogenic capacity of nanoconjugates were studied for model protein, hen egg-white lysozyme (HEWL). The ThT binding assay, fibril size measurement, and electron microscopy results revealed that conjugates suppress fibrillogenesis in HEWL. The highest amyloid inhibition activity obtained against C-PVP and C-PVP-Au was 31 μg.mL−1 and 30 μg.mL−1, respectively. The dissociation activity for amyloid aggregation was observed against Q-PVP and Q-PVP-Au at 29 μg.mL−1 and 27 μg.mL−1, respectively. The antibacterial studies show significant efficacy against Escherichia coli (E. coli) in the presence of C-PVP and C-PVP-Au. The substantial antibacterial potential of C-PVP@PVA and C-PVP-Au@PVA membranes shows promising wound healing applications. The PVA membranes with nanoparticles promote the antibacterial activity and wound healing activity in the Drosophila model. C-PVP-Au@PVA membrane healed the wound faster than the C-PVP@PVA, and it can be used for better results in wound healing. Thus, C-PVP-Au and C-PVP have higher bioavailability and stability and can act as multifunctional therapeutic agents for amyloid-related diseases and as wound healing agents. [ABSTRACT FROM AUTHOR]

Primary proteasomopathies have recently emerged as a new class of rare early-onset neurodevelopmental disorders (NDDs) caused by pathogenic variants in the PSMB1 , PSMC1 , PSMC3 , or PSMD12 proteasome genes. Proteasomes are large multi-subunit protein complexes that maintain cellular protein homeostasis by clearing ubiquitin-tagged damaged, misfolded, or unnecessary proteins. In this study, we have identified PSMD11 as an additional proteasome gene in which pathogenic variation is associated with an NDD-causing proteasomopathy. PSMD11 loss-of-function variants caused early-onset syndromic intellectual disability and neurodevelopmental delay with recurrent obesity in 10 unrelated children. Our findings demonstrate that the cognitive impairment observed in these individuals could be recapitulated in Drosophila melanogaster with depletion of the PMSD11 ortholog Rpn6 , which compromised reversal learning. Our investigations in subject samples further revealed that PSMD11 loss of function resulted in impaired 26S proteasome assembly and the acquisition of a persistent type I interferon (IFN) gene signature, mediated by the integrated stress response (ISR) protein kinase R (PKR). In summary, these data identify PSMD11 as an additional member of the growing family of genes associated with neurodevelopmental proteasomopathies and provide insights into proteasomal biology in human health. [Display omitted] Deb et al. have identified PSMD11 , which encodes a proteasome subunit, as a causative factor for a neurodevelopmental disorder. Their investigations involving clinical phenotype analysis and proband-derived cell lines as well as animal and cellular models have established an association between PSMD11 variants and impaired learning abilities, obesity, and auto-inflammation. [ABSTRACT FROM AUTHOR]

Plant extracts are increasingly recognized for their potential in modulating (postprandial) blood glucose levels. In this context, root extracts are of particular interest due to their high concentrations and often unique spectrum of plant bioactives. To identify new plant species with potential glucose-lowering activity, simple and robust methodologies are often required. For this narrative review, literature was sourced from scientific databases (primarily PubMed) in the period from June 2022 to January 2024. The regulatory targets of glucose homeostasis that could be modulated by bioactive plant compounds were used as search terms, either alone or in combination with the keyword “root extract”. As a result, we present a comprehensive methodological toolbox for studying the glucose homeostasis modulating properties of plant extracts and its constituents. The described assays encompass in-vitro investigations involving enzyme inhibition (α-amylase, α-glucosidase, dipeptidyl peptidase 4), assessment of sodium-dependent glucose transporter 1 activity, and evaluation of glucose transporter 4 translocation. Furthermore, we describe a patch-clamp technique to assess the impact of extracts on KATP channels. While validating in-vitro findings in living organisms is imperative, we introduce two screen able in-vivo models (the hen’s egg test and Drosophila melanogaster). Given that evaluation of the bioactivity of plant extracts in rodents and humans represents the current gold standard, we include approaches addressing this aspect. In summary, this review offers a systematic guide for screening plant extracts regarding their influence on key regulatory elements of glucose homeostasis, culminating in the assessment of their potential efficacy in-vivo. Moreover, application of the presented toolbox might contribute to further close the knowledge gap on the precise mechanisms of action of plant-derived compounds. [ABSTRACT FROM AUTHOR]

The arthropod mushroom body is well-studied as an expansion layer representing olfactory stimuli and linking them to contingent events. However, 8% of mushroom body Kenyon cells in Drosophila melanogaster receive predominantly visual input, and their function remains unclear. Here, we identify inputs to visual Kenyon cells using the FlyWire adult whole-brain connectome. Input repertoires are similar across hemispheres and connectomes with certain inputs highly overrepresented. Many visual neurons presynaptic to Kenyon cells have large receptive fields, while interneuron inputs receive spatially restricted signals that may be tuned to specific visual features. Individual visual Kenyon cells randomly sample sparse inputs from combinations of visual channels, including multiple optic lobe neuropils. These connectivity patterns suggest that visual coding in the mushroom body, like olfactory coding, is sparse, distributed, and combinatorial. However, the specific input repertoire to the smaller population of visual Kenyon cells suggests a constrained encoding of visual stimuli. The Drosophila mushroom body, a well-studied olfactory learning center, also receives visual input with unknown function. Here, the authors leverage the FlyWire connectome to identify and characterize properties of visual inputs to the mushroom body. [ABSTRACT FROM AUTHOR]

Micrococcal nuclease sequencing is the state-of-the-art method for determining chromatin structure and nucleosome positioning. Data analysis is complex due to the AT-dependent sequence bias of the endonuclease and the requirement for high sequencing depth. Here, we present the nucleosome-based MNase accessibility (nucMACC) pipeline unveiling the regulatory chromatin landscape by measuring nucleosome accessibility and stability. The nucMACC pipeline represents a systematic and genome-wide approach for detecting unstable ("fragile") nucleosomes. We have characterized the regulatory nucleosome landscape in Drosophila melanogaster, Saccharomyces cerevisiae, and mammals. Two functionally distinct sets of promoters were characterized, one associated with an unstable nucleosome and the other being nucleosome depleted. We show that unstable nucleosomes present intermediate states of nucleosome remodeling, preparing inducible genes for transcriptional activation in response to stimuli or stress. The presence of unstable nucleosomes correlates with RNA polymerase II proximal pausing. The nucMACC pipeline offers unparalleled precision and depth in nucleosome research and is a valuable tool for future nucleosome studies. [ABSTRACT FROM AUTHOR]

Long-read sequencing, exemplified by PacBio, revolutionizes genomics, overcoming challenges like repetitive sequences. However, the high DNA requirement (> 1 µg) is prohibitive for small organisms. We develop a low-input (100 ng), low-cost, and amplification-free library-generation method for PacBio sequencing (LILAP) using Tn5-based tagmentation and DNA circularization within one tube. We test LILAP with two Drosophila melanogaster individuals, and generate near-complete genomes, surpassing preexisting single-fly genomes. By analyzing variations in these two genomes, we characterize mutational processes: complex transpositions (transposon insertions together with extra duplications and/or deletions) prefer regions characterized by non-B DNA structures, and gene conversion of transposons occurs on both DNA and RNA levels. Concurrently, we generate two complete assemblies for the endosymbiotic bacterium Wolbachia in these flies and similarly detect transposon conversion. Thus, LILAP promises a broad PacBio sequencing adoption for not only mutational studies of flies and their symbionts but also explorations of other small organisms or precious samples. Pacific Biosciences (PacBio) High Fidelity (HiFi) long-read sequencing usually requires a relatively high amount of DNA input (> 1 µg). Here the authors develop LILAP, a Low-Input (100 ng), Low-cost, and Amplification-free library-generation method for PacBio sequencing, enabling the generation of two high-quality individual fly genomes. [ABSTRACT FROM AUTHOR]