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Accumulating evidence demonstrates that ferroptosis may be important in the pathophysiological process of traumatic brain injury (TBI). As a major hormone of the pineal gland, melatonin exerts many beneficial effects on TBI, but there is no information regarding the effects of melatonin on ferroptosis after TBI. As expected, TBI resulted in the time‐course changes of ferroptosis‐related molecules expression and iron accumulation in the ipsilateral cortex. Importantly, we found that treating with melatonin potently rescued TBI induced the changes mentioned above and improved functional deficits versus vehicle. Similar results were obtained with a ferroptosis inhibitor, liproxstatin‐1. Moreover, the protective effect of melatonin is likely dependent on melatonin receptor 1B (MT2). Although ferritin plays a vital role in iron metabolism by storing excess cellular iron, its precise function in the brain, and whether it involves melatonin's neuroprotection remain unexplored. Considering ferritin H (Fth) is expressed predominantly in the neurons and global loss of Fth in mice induces early embryonic lethality, we then generated neuron‐specific Fth conditional knockout (Fth‐KO) mice, which are viable and fertile but have altered iron metabolism. In addition, Fth‐KO mice were more susceptible to ferroptosis after TBI, and the neuroprotection by melatonin was largely abolished in Fth‐KO mice. In vitro siFth experiments further confirmed the results mentioned above. Taken together, these data indicate that melatonin produces cerebroprotection, at least partly by inhibiting neuronal Fth‐mediated ferroptosis following TBI, supporting the notion that melatonin is an excellent ferroptosis inhibitor and its anti‐ferroptosis provides a potential therapeutic target for treating TBI. [ABSTRACT FROM AUTHOR]

Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) is one of the most predominant calliphorid species which arrives and colonizes a cadaver first in its native range of the Australian and Oriental regions, and the intra-puparial stage of this species accounts for about half of its immature stage. Therefore, establishing a reliable aging method of the intra-puparial stage of C. megacephala is very important to accurately estimate the minimum postmortem interval (PMI min). In this study, actin was used as an internal reference gene to study the expression of three genes, ecdysone receptor gene ecr , white-eye gene white , and heat shock protein gene hsp 70, at different time points during intra-puparial development of C. megacephala. Quantification through real-time PCR revealed that these genes can be used to age the intra-puparial period of C. megacephala as they exhibit regular changes and gene expression level was temperature-dependent. The overall gene expression profile of ecr showed a downward trend throughout the intra-puparial stage. White expression increased steadily until it peaked when intra-puparial development reached 45%, and the expression began to decrease when the intra-puparial development reached 55%. hsp 70 was first down-regulated at 0–15% of intra-puparial development, and then slightly up-regulated at 15–40%, and finally down-regulated again until the end of intra-puparial development. This study provides molecular indicators of age during the intra-puparial stage of C. megacephala , and combining gene expression with the morphological methods can lead to more accurate estimation for PMI min. Unlabelled Image • Chrysomya megacephala is a forensically important species for PMImin estimation. • Expression of three target genes during the intra-puparial stage was studied. • Expression of genes exhibit regular changes and temperature dependence. • Combining our results with morphological methods can generate a more precise PMImin. [ABSTRACT FROM AUTHOR]

BACKGROUND Silkworm ( Bombyx mori) is an economically important insect. It is relatively less resistant to certain chemicals and environment exposures such as pesticides and pathogens. After pesticide exposures, the silkworms are more susceptible to microbial infections. The mechanism underlying the susceptibility might be related to immune response and oxidative stress. RESULTS A sublethal dose of phoxim combined with Bombyx mori nucleopolyhedrovirus (BmNPV) elevated the silkworm mortality at 96 h. We found a higher content of H2O2 and increased levels of genes related to oxidative stress and immune response after treatment with a sublethal dose of phoxim for 24 h or 48 h. However, such response decreased with longer pesticide treatment. Mortality increased by 44% when B. mori was exposed to combined treatment with BmNPV and phoxim rather than BmNPV alone. The level of examined immune-related and oxidative-stress-related genes significantly decreased in the combined treatment group compared with the BmNPV group. Our results indicated that, with long-term exposure to pesticides such as OPs, even at sublethal dose, the oxidative stress response and immune responses in silkworm were inhibited, which may lead to further immune impairment and accumulation of oxidative stress, resulting in susceptibility to the virus and harm to the silkworm. CONCLUSION Our study provided insights for understanding the susceptibility to pathogen after pesticide exposures, which may promote the development of better pesticide controls to avoid significant economic losses. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

ABSTRACT Organophosphate pesticides are applied widely in the world for agricultural purposes, and their exposures often resulted in non-cocooning of Bombyx mori in China. Silkworm midgut is the major organ for digestion and nutrient absorption, importantly it is also a barrier against foreign substances and chemical pesticides. The purpose of this study was to determine the mechanism of oxidative injury in silkworm midgut with phoxim induction. The results showed that the transcription level of oxidative phosphorylation signaling pathway genes of midgut under phoxim stress. Digital gene expression (DGE) analysis revealed that 24 electron transport chain (ETC)-related genes were upregulated. Quantitative real time polymerase chain reaction results indicated that the ETC the genes encoding NADH-CoQ1, Succinic-Q, cyt c reductase-S, cyt c oxidase-S, cytochrome c oxidase polypeptide IV, ATP synthase, and vacuolar H+ ATP synthase were all significantly up-regulated by 1.50-, 1.31-, 1.42-, 1.44-, 1.70-, 2.03- and 1.43-fold, respectively. Phoxim induction enhanced the activity of ETC complex in mitochondria, and induced the accumulation of ROS in midgut. These results indicated that trace phoxim enhanced respiration in midgut, and the imbalance between the activity changes of ETC may led to reactive oxygen species accumulation. The ETC of mitochondria may be potential biomarkers of midgut toxicity in B. mori caused by phoxim exposure. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 167-175, 2017. [ABSTRACT FROM AUTHOR]

Highlights: [•] We performed a DGE analysis of the midgut in the B. mori at 24h exposed to phoxim. [•] The impact on detoxification, apoptosis and immune defense were addressed. [•] Phoxim exposure leads to increased apoptosis. [Copyright &y& Elsevier]

Florfenicol (FF) is a new antibiotic commonly used in sericulture. This study aimed to examine the effects of low (LC: 0.06 g/L), medium (MC: 0.12 g/L), and high (HC: 1.2 g/L) concentrations of FF on the midgut physiological functions of the silkworm, Bombyx mori (L.) (Lepidoptera: Bombycidae). The results showed that the body weight and the whole cocoon weight of silkworms decreased and the development duration of the fifth instar was prolonged in the HC group. The structure of intestinal microbiota of silkworm larvae was changed by high FF exposure. Specifically, the abundance of conditional pathogens (Curtobacterium, Sanguibater, etc.) was significantly increased, whereas the abundance of Pseudomonas and Pedobacter was decreased significantly. Additionally, the intestinal reactive oxygen species level at 72 h was significantly elevated, and the muscle layer had become loose, together with the appearance of gut goblet cell atrophy. We observed that the increase in Lactobacillus abundance led to a reduction in intestinal fluid pH, resulting in decreased α‐amylase and protease activities, whereas lipase activity exhibited an elevation. The results demonstrated that the accumulation of peroxides induced by exposure to 1.2 g/L FF caused intestinal damage, and the decrease in pH resulting from alterations in microbial composition and structure affected digestive enzyme activity, collectively leading to physiological impairment of the silkworm midgut. These findings provide a valuable reference for the safe use of FF in sericulture. [ABSTRACT FROM AUTHOR]

Silkworm (Bombyx mori) is an economically important insect. However, the survival of silkworms has been significantly affected by the assault of chemical pesticides on mulberry trees through aerial application and water currents. Phoxim is a broad-spectrum organophosphorus insecticide widely used in China. Currently, very little is known about the non-neuronal effects of sublethal exposure to phoxim. The purpose of this study was to investigate the non-neuronal effects of sublethal phoxim exposure in the silkworm midgut, with a focus on nutrient metabolism. After phoxim treatment, lipase activity in the silkworm was shown to be up-regulated at 24 h before a decreasing trend was seen. Meanwhile, α-amylase activity showed the opposite trend. The expression levels of mitochondrial respiratory chain-related genes were all up-regulated at 24 h before falling continuously. To ensure that the effects of phoxim on nutrient metabolism were not simply a consequence of a decrease in mulberry consumption, the silkworms were treated with a reduced-food diet before the digestive enzyme activities and the transcription levels of mitochondrial respiratory chain-related genes were analyzed. Our results showed that the patterns in the reduced-diet and phoxim-exposed silkworm were markedly different, suggesting the alterations in the phoxim-exposed silkworm cannot readily be explained by nutrient deprivation Unlabelled Image • Phoxim exposure alters the mRNA levels of glucose and lipid metabolism-related genes. • Lipase activity showed the opposite trend to α-amylase activity after exposure. • The patterns in the reduced-diet and phoxim-exposed silkworm were markedly different. [ABSTRACT FROM AUTHOR]

Organophosphate pesticides are widely applied worldwide for agricultural purposes, and their exposures often result in adverse effects on Bombyx mori. The insect gut is a complicated ecosystem inhabited by a large number of microbes that play important roles in insect physiology and behavior. Recent studies have reported that alteration of their microbiota due to stressful conditions or environmental changes has been linked to a compromised health status and a susceptibility to diseases. In the present study, we aimed to assess the effects of phoxim exposure on intestinal microbes in silkworms. The results showed that phoxim exposure increased the bacterial community evenness and altered the structure of gut microbiota in silkworm larvae. The abundances of several genera, such as Methylobacterium and Aurantimonadaceae , in phoxim-treated larval guts were significantly reduced compared with the H 2 O-treated group, whereas the abundances of non-dominant bacteria, such as Staphylococcus, were significantly increased. Moreover, phoxim inhibited the expressions of antimicrobial peptides (AMPs) at the mRNA level and enhanced the pathogenesis of Enterobacter cloacae (E. cloacae) against silkworm larvae, suggesting that the immune system was inhibited after phoxim exposure. Therefore, the gut microbial community shifts were apparent after phoxim exposure. The compositional and structural changes of intestinal microbes caused by phoxim exposure might affect the normal function of the intestinal tract of silkworm. These results highlighted the importance of the gut bacterial community when investigating the mechanisms of midgut injury after pesticide exposure in Bombyx mori. Image 1 • Low-level phoxim inhibited the mRNA expressions of antimicrobial peptides. • Low-level phoxim enhanced the pathogenesis of E. cloacae against silkworm larvae. • The gut microbial community shifts were apparent after phoxim exposure. • The structural changes of gut microbes might affect normal function of silkworm gut. [ABSTRACT FROM AUTHOR]

Ferroptosis is a form of regulated cell death that is mainly triggered by iron-dependent lipid peroxidation. A growing body of evidence suggests that ferroptosis is involved in the pathophysiology of traumatic brain injury (TBI), and tropomyosin-related kinase B (TrkB) deficiency would mediate TBI pathologies. As an agonist of TrkB and an immediate precursor of melatonin, N-acetyl serotonin (NAS) exerts several beneficial effects on TBI, but there is no information regarding the role of NAS in ferroptosis after TBI. Here, we examined the effect of NAS treatment on TBI-induced functional outcomes and ferroptosis. Remarkably, the administration of NAS alleviated TBI-induced neurobehavioral deficits, lesion volume, and neurodegeneration. NAS also rescued TBI-induced mitochondrial shrinkage, the changes in ferroptosis-related molecule expression, and iron accumulation in the ipsilateral cortex. Similar results were obtained with a well-established ferroptosis inhibitor, liproxstatin-1. Furthermore, NAS activated the TrkB/PI3K/Akt/Nrf2 pathway in the mouse model of TBI, while inhibition of PI3K and Nrf2 weakened the protection of NAS against ferroptosis both in vitro and in vivo , suggesting that a possible pathway linking NAS to the action of anti-ferroptosis was TrkB/PI3K/Akt/Nrf2. Given that ferritin H (Fth) is a known transcription target of Nrf2, we then investigated the effects of NAS on neuron-specific Fth knockout (Fth -KO) mice. Strikingly, Fth deletion almost abolished the protective effects of NAS against TBI-induced ferroptosis and synaptic damage, although Fth deletion-induced susceptibility toward ferroptosis after TBI was reversed by an iron chelator, deferoxamine. Taken together, these data indicate that the TrkB agonist NAS treatment appears to improve brain function after TBI by suppressing ferroptosis, at least in part, through activation of the PI3K/Akt/Nrf2/Fth pathway, providing evidence that NAS is likely to be a promising anti-ferroptosis agent for further treatment for TBI. [Display omitted] • NAS reduces TBI-induced neurological deficits and neurodegeneration. • NAS is a potent anti-ferroptotic compound, and mitigates TBI-induced ferroptosis. • NAS prevents TBI-induced ferroptosis through the PI3K/Akt/Nrf2/Fth pathway. • Fth deletion abolishes the effects of NAS on TBI-induced ferroptosis and synaptic damage. [ABSTRACT FROM AUTHOR]

Global warming is known to affect the growth, development and reproduction of insects. In this study, the larvae developmental process and endogenous hormone levels under high temperature (36 °C) stress were investigated in the lepidopteran model insect Bombyx mori (B. mori). After high temperature treatment, the duration of 5th instar larvae was shortened by 28 ± 2 h, the content of 20-hydroxyecdysone(20E) in hemolymph was significantly increased, and the transcription levels of the 20E response genes E93, Br–C, USP and E75 were up-regulated by 1.35-, 1.25-, 1.28-, and 1.27-fold, respectively. High temperature treatment also elevated the phosphorylation level of Akt and activated the downstream BmCncC/keap1 pathway, and the transcription levels of the 20E synthesis-related genes cyp302a1, cyp306a1, cyp314a1 and cyp315a1 were up-regulated by 1.12-, 1.51-, 2.17- and 1.23-fold, respectively. The transcription levels of cyp302a1 and cyp306a1 were significantly decreased in BmN cells after treatment with the double stranded RNA of BmCncC (dsBmCncC), whereas their transcription levels were significantly increased (2.15- and 1.31-fold, respectively) after treatment with the CncC agonist Curcumin. These results demonstrated that high temperature treatment promoted the metamorphosis and the BmCncC/keap1 pathway played a role in the metamorphosis of B. mori. Our results provided clues for understanding the CncC/keap1 pathway-mediated regulation of metamorphosis of Lepidopteran insects. • High temperature stress promotes the larvae development and changes endogenous hormone levels. • The activation of BmCncC/keap1 pathway is one of the reasons for the increase of 20E level. • BmCncC mediates ecdysone synthesis via Cyp302a1 and Cyp306a1. [ABSTRACT FROM AUTHOR]

Dynamin-related protein 1 (Drp1) is a key regulator of mitochondrial fission. Our previous studies proved that the inhibition of Drp1 may help attenuate traumatic brain injury (TBI)-induced functional outcome and cell death through maintaining normal mitochondrial morphology and inhibiting activation of apoptosis. However, the molecular mechanisms of Drp1 after TBI remain poorly understood. In this study, we investigated the role of mitochondrial division inhibitor 1 (Mdivi-1), a small molecule inhibitor of Drp1, in underlying mechanisms of general autophagy and mitochondria autophagy (mitophagy) after experimental TBI. In vivo , we found that autophagosomes accumulated in cortical neurons at 24 h after TBI, owing to the enhanced autophagy indicated by the accumulation of LC3 and the decrease of p62; but Mdivi-1 reversed the enhancement. Mdivi-1 also alleviated the number of LC3 puncta and TUNEL-positive structures in cells, indicating that autophagy maybe involved in Mdivi-1′s anti-apoptosis effects. Then, the expression level of mitochondrial dynamics related and mitophagy related proteins was assessed using the isolated mitochondria. The results showed that TBI-induced mitochondrial fission (represented by Drp1), mtDNA concentration down-regulation and PTEN induced putative kinase 1 (PINK1)-Parkin mediated mitophagy activation were all inhibited by Mdivi-1. In addition, TBI-induced blood-brain barrier (BBB) disruption and matrix metalloproteinases (MMP)-9 expression up-regulation were inhibited following Mdivi-1 treatment. In vitro , Mdivi-1 significantly alleviated the scratch injury-induced cell death, loss of mitochondrial membrane potential, reactive oxygen species (ROS) production and ATP reduction in primary cortical neurons (PCNs). Additionally, the lysosome inhibitor chloroquine (CQ) abrogated the Mdivi-1-induced decrease in autophagosomes accumulation and cell death at 24 h both in the basal state and under the conditions of scratch cell injury. Together, these data demonstrate that Mdivi-1 mitigates TBI-induced BBB disruption and cell death at least in part by a mechanism involving inhibiting autophagy dysfunction and mitophagy activation. [ABSTRACT FROM AUTHOR]