Concomitant changes in radiation resistance and trehalose levels during life stages of Drosophila melanogaster suggest radio-protective function of trehalose

Genome-Wide Scanning Loci and Differentially Expressed Gene Analysis Unveils the Molecular Mechanism of Chlorantraniliprole Resistance in Spodoptera frugiperda

Chlorantraniliprole has been widely used to controlSpodoptera frugiperda, but it has led to the development of chlorantraniliprole resistance. Multiomics analysis of strains with two extreme traits helps to elucidate the complex mechanisms involved. Herein, following genome resequencing and application of the Euclidean distance algorithm, 550 genes within a 16.20-Mb-linked region were identified from chlorantraniliprole-resistant (Ch-R) and chlorantraniliprole-susceptible (Ch-Sus) strains. Using transcriptome sequencing, 2066 differentially expressed genes were identified between Ch-R and Ch-Sus strains. Through association analysis, three glutathione S-transferase family genes and four trehalose transporter genes were selected for functional verification. Notably, SfGSTD1 had the strongest binding ability with chlorantraniliprole and is responsible for chlorantraniliprole tolerance. The Ch-R strain also increased the intracellular trehalose content by upregulating the transcription of SfTret1, thereby contributing to chlorantraniliprole resistance. These findings provide a new perspective to reveal the mechanism of resistance of agricultural pests to insecticides.

High-throughput screening strategies for space-based radiation countermeasure discovery

As humanity begins to venture further into space, approaches to better protect astronauts from the hazards found in space need to be developed. One particular hazard of concern is the complex radiation that is ever present in deep space. Currently, it is unlikely enough spacecraft shielding could be launched that would provide adequate protection to astronauts during long-duration missions such as a journey to Mars and back. In an effort to identify other means of protection, prophylactic radioprotective drugs have been proposed as a potential means to reduce the biological damage caused by this radiation. Unfortunately, few radioprotectors have been approved by the FDA for usage and for those that have been developed, they protect normal cells/tissues from acute, high levels of radiation exposure such as that from oncology radiation treatments. To date, essentially no radioprotectors have been developed that specifically counteract the effects of chronic low-dose rate space radiation. This review highlights how high-throughput screening (HTS) methodologies could be implemented to identify such a radioprotective agent. Several potential target, pathway, and phenotypic assays are discussed along with potential challenges towards screening for radioprotectors. Utilizing HTS strategies such as the ones proposed here have the potential to identify new chemical scaffolds that can be developed into efficacious radioprotectors that are specifically designed to protect astronauts during deep space journeys. The overarching goal of this review is to elicit broader interest in applying drug discovery techniques, specifically HTS towards the identification of radiation countermeasures designed to be efficacious towards the biological insults likely to be encountered by astronauts on long duration voyages.

Dextran sodium sulfate alters antioxidant status in the gut affecting the survival of Drosophila melanogaster

Inflammatory bowel disease (IBD) is a group of disorders characterized by chronic inflammation in the intestine. Several studies confirmed that oxidative stress induced by an enormous amount of reactive free radicals triggers the onset of IBD. Currently, there is an increasing trend in the global incidence of IBD and it is coupled with a lack of adequate long-term therapeutic options. At the same time, progress in research to understand the pathogenesis of IBD has been hampered due to the absence of adequate animal models. Currently, the toxic chemical Dextran Sulfate Sodium (DSS) induced gut inflammation in rodents is widely perceived as a good model of experimental colitis or IBD. Drosophila melanogaster, a genetic animal model, shares ~ 75% sequence similarity to genes causing different diseases in humans and also has conserved digestion and absorption features. Therefore, in the current study, we used Drosophila as a model system to induce and investigate DSS-induced colitis. Anatomical, biochemical, and molecular analyses were performed to measure the levels of inflammation and cellular disturbances in the gastrointestinal (GI) tract of Drosophila. Our study shows that DSS-induced inflammation lowers the levels of antioxidant molecules, affects the life span, reduces physiological activity and induces cellular damage in the GI tract mimicking pathophysiological features of IBD in Drosophila. Such a DSS-induced Drosophila colitis model can be further used for understanding the molecular pathology of IBD and screening novel drugs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03349-2.

Systematic toxicity assessment of CdTe quantum dots in Drosophila melanogaster

The risk assessment of cadmium (Cd)-based quantum dots (QDs) used for biomedical nanotechnology applications has stern toxicity concerns. Despite cytotoxicity studies of cadmium telluride (CdTe) QDs, the systematic in vivo study focusing on its organismal effects are more relevant to public health. Therefore, the present study aims to investigate the effect of chemically synthesized 3-mercapto propionic acid-functionalized CdTe QDs on organisms' survival, development, reproduction, and behaviour using Drosophila melanogaster as a model. The sub-cellular impact on the larval gut was also evaluated. First/third instar larvae or the adult Drosophila were exposed orally to green fluorescence emitting CdTe QDs (0.2-100 μM), and organisms' longevity, emergence, reproductive performance, locomotion, and reactive oxygen species (ROS), and cell death were assessed. Uptake of semiconductor CdTe QDs was observed as green fluorescence in the gut. A significant decline in percentage survivability up to 80% was evident at high CdTe QDs concentrations (25 and 100 μM). The developmental toxicity was marked by delayed and reduced fly emergence after CdTe exposure. The teratogenic effect was evident with significant wing deformities at 25 and 100 μM concentrations. However, at the reproductive level, adult flies' fecundity, fertility, and hatchability were highly affected even at low concentrations (1 μM). Surprisingly, the climbing ability of Drosophila was unaffected at any of the used CdTe QDs concentrations. In addition to organismal toxicity, the ROS level and cell death were elevated in gut cells, confirming the sub-cellular toxicity of CdTe QDs. Furthermore, we observed a significant rescue in CdTe QDs-associated developmental, reproductive, and survival adversities when organisms were co-exposed with N-acetyl-cysteine (NAC, an antioxidant) and CdTe QDs. Overall, our findings indicate that the environmental release of aqueously dispersible CdTe QDs raises a long-lasting health concern on the development, reproduction, and survivability of an organism.

Classes of Drugs that Mitigate Radiation Syndromes

We previously reported several vignettes on types and classes of drugs able to mitigate acute and, in at least one case, late radiation syndromes in mice. Most of these had emerged from high throughput screening (HTS) of bioactive and chemical drug libraries using ionizing radiation-induced lymphocytic apoptosis as a readout. Here we report the full analysis of the HTS screen of libraries with 85,000 small molecule chemicals that identified 220 "hits." Most of these hits could be allocated by maximal common substructure analysis to one of 11 clusters each containing at least three active compounds. Further screening validated 23 compounds as being most active; 15 of these were cherry-picked based on drug availability and tested for their ability to mitigate acute hematopoietic radiation syndrome (H-ARS) in mice. Of these, five bore a 4-nitrophenylsulfonamide motif while 4 had a quinoline scaffold. All but two of the 15 significantly (p < 0.05) mitigated H-ARS in mice. We had previously reported that the lead 4-(nitrophenylsulfonyl)-4-phenylpiperazine compound (NPSP512), was active in mitigating multiple acute and late radiation syndromes in mice of more than one sex and strain. Unfortunately, the formulation of this drug had to be changed for regulatory reasons and we report here on the synthesis and testing of active analogs of NPSP512 (QS1 and 52A1) that have increased solubility in water and in vivo bioavailability while retaining mitigator activity against H-ARS (p < 0.0001) and other radiation syndromes. The lead quinoline 057 was also active in multiple murine models of radiation damage. Taken together, HTS of a total of 150,000 bioactive or chemical substances, combined with maximal common substructure analysis has resulted in the discovery of diverse groups of compounds that can mitigate H-ARS and at least some of which can mitigate multiple radiation syndromes when given starting 24 h after exposure. We discuss what is known about how these agents might work, and the importance of formulation and bioavailability.

Drosophila as an emerging model organism for studies of food-derived antioxidants

Dietary supplementation with antioxidants provides health benefits by preventing diseases caused by oxidative stress and damage. Consequently, there has been growing interest in the study of antioxidative foods and their active ingredients. Oxidative stress and antioxidative responses are mechanistically conserved from Drosophila to mammals. Therefore, as a well-established model organism with a short life cycle and advantages of genetic manipulation, the fruit fly has been increasingly employed to assess functions of antioxidants in vivo. In this review, the antioxidative defense mechanisms, methods used and assays developed in Drosophila to evaluate antioxidant supplementation, are highlighted. The main manifestations of antioxidation include reduction of reactive species, up-regulation of endogenous antioxidants, inhibition on oxidative damage to biomacromolecules, enhanced resistance against oxidative stress and extension of lifespan, which are related to the activations of nuclear factor erythroid 2-related factor 2-antioxidant response element pathway and other adaptive responses. Moreover, the key considerations and future perspectives for the application of Drosophila models in the studies of food-derived antioxidants are discussed.

Insight into the evolutionary profile of radio-resistance among insects having intrinsically evolved defence against radiation toxicity

Ionizing radiation (IR) has wide-ranging applications in various fields. In agriculture, pest control is one of the important applications, because insect pests have become a threat to the global agriculture industry. IR are used routinely to prevent crop loss and to protect stored food commodities. Radio-sterilization and disinfestation treatments are commonly used procedures for insect pest control. From various studies on insect radio-sterilization and disinfestation, it has been established that compared to vertebrates' insects have high levels of radiation resistance. Therefore, to achieve adequate radio-sterilization/disinfestation; exposure to high doses of IR is necessary. However, studies over decades made a presumption that radiation resistance is general among insects. Recent studies have shown that some insect orders are having high IR resistance and some insect orders are sensitive to IR. These studies have clarified that radiation resistance is not uniform throughout insect class. The present review is an attempt to insight at the evolutionary profile of insect species studied for radio-sterilization and disinfestation treatment and are having the trait of radio-resistance. From various studies on insect radiation resistance and after phylogenetic analysis of insect species it appears that the evolutionary near species have drastically different levels of radio-resistance and trait of radiation resistance appears to be independent of insect evolution.

Regulatory Functions of Nilaparvata lugens GSK-3 in Energy and Chitin Metabolism

Glucose metabolism is a biologically important metabolic process. Glycogen synthase kinase (GSK-3) is a key enzyme located in the middle of the sugar metabolism pathway that can regulate the energy metabolism process in the body through insulin signaling. This paper mainly explores the regulatory effect of glycogen synthase kinase on the metabolism of glycogen and trehalose in the brown planthopper (Nilaparvata lugens) by RNA interference. In this paper, microinjection of the target double-stranded GSK-3 (dsGSK-3) effectively inhibited the expression of target genes in N. lugens. GSK-3 gene silencing can effectively inhibit the expression of target genes (glycogen phosphorylase gene, glycogen synthase gene, trehalose-6-phosphate synthase 1 gene, and trehalose-6-phosphate synthase 2 gene) in N. lugens and trehalase activity, thereby reducing glycogen and glucose content, increasing trehalose content, and regulating insect trehalose balance. GSK-3 can regulate the genes chitin synthase gene and glucose-6-phosphate isomerase gene involved in the chitin biosynthetic pathway of N. lugens. GSK-3 gene silencing can inhibit the synthesis of chitin N. lugens, resulting in abnormal phenotypes and increased mortality. These results indicated that a low expression of GSK-3 in N. lugens can regulate the metabolism of glycogen and trehalose through the insulin signal pathway and energy metabolism pathway, and can regulate the biosynthesis of chitin, which affects molting and wing formation. The relevant research results will help us to more comprehensively explore the molecular mechanism of the regulation of energy and chitin metabolism of insect glycogen synthase kinases in species such as N. lugens.

Proteomics Reveals Distinct Changes Associated with Increased Gamma Radiation Resistance in the Black Yeast Exophiala dermatitidis

The yeast Exophiala dermatitidis exhibits high resistance to γ-radiation in comparison to many other fungi. Several aspects of this phenotype have been characterized, including its dependence on homologous recombination for the repair of radiation-induced DNA damage, and the transcriptomic response invoked by acute γ-radiation exposure in this organism. However, these findings have yet to identify unique γ-radiation exposure survival strategies-many genes that are induced by γ-radiation exposure do not appear to be important for recovery, and the homologous recombination machinery of this organism is not unique compared to more sensitive species. To identify features associated with γ-radiation resistance, here we characterized the proteomes of two E. dermatitidis strains-the wild type and a hyper-resistant strain developed through adaptive laboratory evolution-before and after γ-radiation exposure. The results demonstrate that protein intensities do not change substantially in response to this stress. Rather, the increased resistance exhibited by the evolved strain may be due in part to increased basal levels of single-stranded binding proteins and a large increase in ribosomal content, possibly allowing for a more robust, induced response during recovery. This experiment provides evidence enabling us to focus on DNA replication, protein production, and ribosome levels for further studies into the mechanism of γ-radiation resistance in E. dermatitidis and other fungi.

Radioprotective role of uric acid: evidence from studies in Drosophila and human dermal fibroblast cells

Exposure to ionizing radiation (IR) is a common phenomenon during medical diagnosis and treatment. IRs are deleterious because cellular exposure to IR can cause a series of molecular events that may lead to oxidative stress and macromolecular damage. Radiation protection is therefore essential and significant for improving safety during these procedures. Over decades several antioxidant molecules have been screened to explore their potential as radio-protectors with little success. Therefore, the current study was carried out to confirm the role of uric acid (UA)-a putative antioxidant molecule in radioprotection using radio-resistant insect Drosophila and human dermal fibroblast (HDF) cells. Here, we demonstrate the depleted levels of UA in the mutant flies of Drosophila melanogaster-rosy and by targeting xanthine oxidase (XO an enzyme involved in UA metabolism), through maintaining flies on an allopurinol mixed diet. Allopurinol is a drug that reduces UA levels by inhibiting XO; it reduces the survival percentage in D. melanogaster compared to wild type flies following gamma irradiation at a dose of 1000 Gy. Enzymatic antioxidants such as superoxide dismutase (SOD), catalase, D. melanogaster glutathione peroxidase (DmGPx) and levels of non-enzymatic antioxidants were measured to evaluate the importance of UA. The results indicate that lack of UA reduces the total antioxidant capacity. The activity of SOD was lowered in male flies. Furthermore, we show that supplementation of UA to HDFs cells in media improved their survival rate following gamma irradiation (2 Gy). From the present study we conclude that UA is a potent antioxidant molecule present in high levels among insects. Also, it appears that UA contributes to the radiation resistance of Drosophila flies. Hence, UA emerges as a promising molecule for mitigating radiation-induced oxidative damage in higher organisms.