Energy metabolism is essential for insect development, reproduction and detoxification. Insects often reallocate energy and resources to manage external stress, balancing the demands of detoxification and reproduction. Glucose transport 4 (Glut4), a glucose transporter, is involved in glucose and lipid metabolism. However, the specific molecular mechanism of Glut4 in insect reproduction, and its role in the response to insecticide-induced oxidative stress remain unclear. In this study, LmGlut4 was identified and analyzed in Locusta migratoria. Silencing of LmGlut4 significantly reduced vitellogenin (Vg) biosynthesis in the fat body and Vg absorption by oocytes, ultimately hindering ovarian development and oocyte maturation. Knockdown of LmGlut4 also inhibited the biosynthesis of key insect hormones, such as juvenile hormone (JH), 20-hydroxyecdysone (20E) and insulin. Furthermore, LmGlut4 knockdown led to reduced triglyceride (TG) and glycogen content in the fat body and ovary, as well as decreased capacity for trehalose biosynthesis in adipocytes. Additionally, dsLmGlut4-treated locusts showed heightened sensitivity to deltamethrin, leading to increased triglyceride depletion during detoxification. This study sheds light on the biological function of LmGlut4 in the ovary and provides potential target genes for exploring biological pest management strategies.

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.

Energy storage and endocrine functions of the Drosophila fat body make it an excellent model for elucidating mechanisms that underlie physiological and pathophysiological organismal metabolism. Combined with Drosophila\'s robust genetic and immunofluorescence microscopy toolkits, studies of Drosophila fat body function are ripe for cell biological analysis. Unlike the larval fat body, which is easily removed as a single, cohesive sheet of tissue, isolating intact adult fat body proves to be more challenging, thus hindering consistent immunofluorescence labeling even within a single piece of adipose tissue. Here, we describe an improved approach to handling Drosophila abdomens that ensures full access of the adult fat body to solutions generally used in immunofluorescence labeling protocols. In addition, we assess the quality of fluorescence reporter expression and antibody immunoreactivity in response to variations in fixative type, fixation incubation time, and detergent used for cellular permeabilization. Overall, we provide several recommendations for steps in a whole-mount staining protocol that results in consistent and robust immunofluorescence labeling of the adult Drosophila fat body.

Ninein (Nin) is a microtubule (MT) anchor at the subdistal appendages of mother centrioles and the pericentriolar material (PCM) of centrosomes that also functions to organize MTs at noncentrosomal MT-organizing centers (ncMTOCs). In humans, the NIN gene is mutated in Seckel syndrome, an inherited developmental disorder. Here, we dissect the protein domains involved in Nin\'s localization and interactions with dynein and ensconsin (ens/MAP7) and show that the association with ens cooperatively regulates MT assembly in Drosophila fat body cells. We define domains of Nin responsible for its localization to the ncMTOC on the fat body cell nuclear surface, localization within the nucleus, and association with Dynein light intermediate chain (Dlic) and ens, respectively. We show that Nin\'s association with ens synergistically regulates MT assembly. Together, these findings reveal novel features of Nin function and its regulation of a ncMTOC.

Iron homeostasis is of critical importance to living organisms. Drosophila melanogaster has emerged as an excellent model to study iron homeostasis, while the regulatory mechanism of iron metabolism remains poorly understood. Herein, we accidently found that knockdown of juvenile hormone (JH) acid methyltransferase (Jhamt) specifically in the fat body, a key rate-limiting enzyme for JH synthesis, led to iron accumulation locally, resulting in serious loss and dysfunction of fat body. Jhamt knockdown-induced phenotypes were mitigated by iron deprivation, antioxidant and Ferrostatin-1, a well-known inhibitor of ferroptosis, suggesting ferroptosis was involved in Jhamt knockdown-induced defects in the fat body. Further study demonstrated that upregulation of Tsf1 and Malvolio (Mvl, homolog of mammalian DMT1), two iron importers, accounted for Jhamt knockdown-induced iron accumulation and dysfunction of the fat body. Mechanistically, Kr-h1, a key transcription factor of JH, acts downstream of Jhamt inhibiting Tsf1 and Mvl transcriptionally. In summary, the findings indicated that fat body-derived Jhamt is required for the development of Drosophila by maintaining iron homeostasis in the fat body, providing unique insight into the regulatory mechanisms of iron metabolism in Drosophila.

Human activities associated with large-scale farms and the monocultures expose honey bees to one type of food. Moreover, there is an ongoing decline of plant species producing pollen and nectar in Europe. A poorly balanced diet affects a number of processes occurring in a bee\'s body. The fat body and hemolymph are the tissues that participate in all of them. Therefore, the aim of our study was to determine the effect of hazel, pine, rapeseed, buckwheat, phacelia and goldenrod pollen on the morphological parameters of fat body trophocytes, the diameters of cell nuclei in oenocytes and the concentrations of compounds involved in energy metabolism (glucose, glycogen, triglycerides and protein). In the cage tests, the bees were fed from the first day of life with sugar candy (control group) or candy with a 10% addition of one of the 6 pollen types. Hemolymph and fat body from various locations were collected from 1-, 7- and 14-day-old workers. Pollen produced by plant species such as hazel and pine increased glucose concentrations in the bee tissues, especially in the hemolymph. It can therefore be concluded that they are valuable sources of energy (in the form of simple carbohydrates) which are quickly used by bees. Pollen from plants blooming in the summer and autumn increased the concentrations of proteins, glycogen and triglycerides in the fat body, especially that from the third tergite. The accumulation of these compounds was associated with an increased the length and width of trophocytes as well as with enhanced metabolic activity, which was evidenced in the increasing diameter of oenocyte cell nuclei. It seems a balanced multi-pollen diet is more valuable for bees, but it is important to understand the effects of the particular pollen types in the context of a mono-diet. In the future, this will make it possible to produce mixtures that can ensure homeostasis in the apian body.

UNASSIGNED: The relationship between adiposity and sepsis has received increasing attention. This study aims to explore the causal relationship between life course adiposity and the sepsis incidence.
UNASSIGNED: Mendelian randomization (MR) method was employed in this study. Instrumental variants were obtained from genome-wide association studies for life course adiposity, including birth weight, childhood body mass index (BMI), childhood obesity, adult BMI, waist circumference, visceral adiposity, and body fat percentage. A meta-analysis of genome-wide association studies for sepsis including 10,154 cases and 454,764 controls was used in this study. MR analyses were performed using inverse variance weighted, MR Egger regression, weighted median, weighted mode, and simple mode. Instrumental variables were identified as significant single nucleotide polymorphisms at the genome-wide significance level (P < 5×10-8). The sensitivity analysis was conducted to assess the reliability of the MR estimates.
UNASSIGNED: Analysis using the MR analysis of inverse variance weighted method revealed that genetic predisposition to increased childhood BMI (OR = 1.29, P = 0.003), childhood obesity (OR = 1.07, P = 0.034), adult BMI (OR = 1.38, P < 0.001), adult waist circumference (OR = 1.01, P = 0.028), and adult visceral adiposity (OR = 1.53, P < 0.001) predicted a higher risk of sepsis. Sensitivity analysis did not identify any bias in the MR results.
UNASSIGNED: The results demonstrated that adiposity in childhood and adults had causal effects on sepsis incidence. However, more well-designed studies are still needed to validate their association.

The caterpillar Anticarsia gemmatalis (Lepidoptera: Noctuidae) is a prevalent pest in soybean plantations, managed using both natural and synthetic chemical products. However, the emergence of resistance in some populations emphasizes the need to explore alternative insecticides. Flupyradifurone, a neurotoxic insecticide, has not been previously used for controlling A. gemmatalis. This study evaluated the potential of flupyradifurone in the management of A. gemmatalis. Initially, the toxicity and anti-feeding effects, as well as histopathological and cytotoxic impacts, of flupyradifurone on A. gemmatalis were evaluated. Subsequently, the indirect effects of flupyradifurone on the midgut and fat body of the predator Podisus nigrispinus (Hemiptera: Pentatomidae) were verified. The results indicate the susceptibility of caterpillars to flupyradifurone, with an LC50 of 5.10 g L-1. Furthermore, the insecticide adversely affects survival, induces an anti-feeding response, and inflicts damage on the midgut of the caterpillars. However, flupyradifurone also leads to side effects in the predator P. nigrispinus through indirect intoxication of the caterpillars, including midgut and fat body damage. While flupyradifurone demonstrates toxicity to A. gemmatalis, suggesting its potential for the chemical control of this pest, the indirect negative effects on the predator indicate the need for its controlled use in integrated pest management programs with the insecticide and the predator.

Until recently, chemical pesticides were one of the most effective means of controlling agricultural pests; therefore, the search for insecticide targets for agricultural pests has been an ongoing problem. Estrogen-related receptors (ERRs) are transcription factors that regulate cellular metabolism and energy homeostasis in animals. Silkworms are highly sensitive to chemical pesticides, making them ideal models for pesticide screening and evaluation. In this study, we detected ERR expression in key organs involved in pesticide metabolism in silkworms (Bombyx mori), including the fat body and midgut. Using ChIP-seq technology, many estrogen- related response elements were identified in the 2000-bp promoter region upstream of metabolism-related genes, almost all of which were potential ERR target genes. The ERR inhibitor, XCT-790, and the endocrine disruptor, bisphenol A, significantly inhibited expression of the ERR target genes, BmTreh-1, BmTret-1, BmPK, BmPFK, and BmHK, in the fat bodies of silkworms, resulting in pupation difficulties in silkworm larvae that ultimately lead to death. In addition, based on the clarification that the ERR can bind to XCT-790, as observed through biofilm interferometry, its three-dimensional spatial structure was predicted, and using molecular docking techniques, small-molecule compounds with a stronger affinity for the ERR were identified. In summary, utilizing the powerful metabolic regulatory function of ERR in Lepidoptera pests, the developed small molecule inhibitors of ERR can be used for future control of Lepidoptera pests.

Modern insects have inhabited the earth for hundreds of millions of years, and part of their successful adaptation lies in their many reproductive strategies. Insect reproduction is linked to a high metabolic rate that provides viable eggs in a relatively short time. In this context, an accurate interplay between the endocrine system and the nutrients synthetized and metabolized is essential to produce healthy offspring. Lipids guarantee the metabolic energy needed for egg formation and represent the main energy source consumed during embryogenesis. Lipids availability is tightly regulated by a complex network of endocrine signals primarily controlled by the central nervous system (CNS) and associated endocrine glands, the corpora allata (CA) and corpora cardiaca (CC). This endocrine axis provides hormones and neuropeptides that significatively affect tissues closely involved in successful reproduction: the fat body, which is the metabolic center supplying the lipid resources and energy demanded in egg formation, and the ovaries, where the developing oocytes recruit lipids that will be used for optimal embryogenesis. The post-genomic era and the availability of modern experimental approaches have advanced our understanding of many processes involved in lipid homeostasis; therefore, it is crucial to integrate the findings of recent years into the knowledge already acquired in the last decades. The present chapter is devoted to reviewing major recent contributions made in elucidating the impact of the CNS/CA/CC-fat body-ovary axis on lipid metabolism in the context of insect reproduction, highlighting areas of fruitful research.