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Environmental Science and Pollution... Mar 2024Malathion serves as a pivotal pesticide in agriculture and the management of the Aedes aegypti mosquito. Despite its widespread use, there is a notable absence of...
Malathion serves as a pivotal pesticide in agriculture and the management of the Aedes aegypti mosquito. Despite its widespread use, there is a notable absence of studies elucidating the mechanisms through which malathion may affect the female reproductive system. Consequently, the objective of this investigation was to assess whether exposing juvenile female rats to low doses of malathion during the juvenile and peripubertal periods could compromise pubertal onset, estradiol levels, and the integrity of the ovaries and uterus while also examining the underlying mechanisms of damage. To achieve this, thirty juvenile female rats were subjected to either a vehicle or malathion (10 mg/kg or 50 mg/kg) between postnatal days 22 and 60, with subsequent verification of pubertal onset. Upon completion of the exposure period, blood samples were collected for estradiol assessment. The ovaries and uterus were then examined to evaluate histological integrity, oxidative stress, and the expression of genes associated with cell proliferation, antiapoptotic responses, and endocrine pathways. Although estradiol levels and pubertal onset remained unaffected, exposure to malathion compromised the integrity and morphometry of the ovaries and uterus. This was evidenced by altered oxidative profiles and changes in the expression of genes regulating the cell cycle, anti-apoptotic processes, and endocrine pathways. Our findings underscore the role of malathion in inducing cell proliferation, promoting cell survival, and causing oxidative damage to the female reproductive system in rats exposed during peripubertal periods.
Topics: Rats; Female; Animals; Malathion; Insecticides; Ovary; Oxidative Stress; Estradiol; Uterus; Gene Expression
PubMed: 38393561
DOI: 10.1007/s11356-024-32494-9 -
Developmental Biology May 2024Many insects undergo the process of metamorphosis when larval precursor cells begin to differentiate to create the adult body. The larval precursor cells retain stem...
Many insects undergo the process of metamorphosis when larval precursor cells begin to differentiate to create the adult body. The larval precursor cells retain stem cell-like properties and contribute to the regenerative ability of larval appendages. Here we demonstrate that two Broad-complex/Tramtrack/Bric-à-brac Zinc-finger (BTB) domain transcription factors, Chronologically inappropriate morphogenesis (Chinmo) and Abrupt (Ab), act cooperatively to repress metamorphosis in the flour beetle, Tribolium castaneum. Knockdown of chinmo led to precocious development of pupal legs and antennae. We show that although topical application of juvenile hormone (JH) prevents the decrease in chinmo expression in the final instar, chinmo and JH act in distinct pathways. Another gene encoding the BTB domain transcription factor, Ab, was also necessary for the suppression of broad (br) expression in T. castaneum in a chinmo RNAi background, and simultaneous knockdown of ab and chinmo led to the precocious onset of metamorphosis. Furthermore, knockdown of ab led to the loss of regenerative potential of larval legs independently of br. In contrast, chinmo knockdown larvae exhibited pupal leg regeneration when a larval leg was ablated. Taken together, our results show that both ab and chinmo are necessary for the maintenance of the larval tissue identity and, apart from its role in repressing br, ab acts as a crucial regulator of larval leg regeneration. Our findings indicate that BTB domain proteins interact in a complex manner to regulate larval and pupal tissue homeostasis.
Topics: Animals; Coleoptera; Gene Expression Regulation, Developmental; Insect Proteins; Juvenile Hormones; Larva; Metamorphosis, Biological; Morphogenesis; Pupa; Transcription Factors; Tribolium; Regeneration
PubMed: 38373692
DOI: 10.1016/j.ydbio.2024.02.006 -
Journal of Insect Physiology May 2024Farnesol, a sesquiterpene found in all eukaryotes, precursor of juvenile hormone (JH) in insects, is involved in signalling, communication, and antimicrobial defence....
Farnesol, a sesquiterpene found in all eukaryotes, precursor of juvenile hormone (JH) in insects, is involved in signalling, communication, and antimicrobial defence. Farnesol is a compound of floral volatiles, suggesting its importance in pollination and foraging behaviour. Farnesol is found in the resin of Baccharis dracunculifolia, from which honeybees elaborate the most worldwide marketable propolis. Bees use propolis to seal cracks in the walls, reinforce the wax combs, and as protection against bacteria and fungi. The introduction within a honeybee hive of a compound with potential hormonal activity can be a challenge to the colony survival, mainly because the transition from within-hive to outside activities of workers is controlled by JH. Here, we tested the hypothesis that exogenous farnesol alters the pacing of developing workers. The first assays showed that low doses of the JH precursor (0.1 and 0.01 µg) accelerate pharate-adult development, with high doses being toxic. The second assay was conducted in adult workers and demonstrated bees that received 0.2 µg farnesol showed more agitated behaviour than the control bees. If farnesol was used by corpora allata (CA) cells as a precursor of JH and this hormone was responsible for the observed behavioural alterations, these glands were expected to be larger after the treatment. Our results on CA measurements after 72 h of treatment showed bees that received farnesol had glands doubled in size compared to the control bees (p < 0.05). Additionally, we expected the expression of JH synthesis, JH degradation, and JH-response genes would be upregulated in the treated bees. Our results showed that indeed, the mean transcript levels of these genes were higher in the treated bees (significant for methyl farnesoate epoxidase and juvenile hormone esterase, p < 0.05). These results suggest farnesol is used in honeybees as a precursor of JH, leading to increasing JH titres, and thus modulating the pacing of workers development. This finding has behavioural and ecological implications, since alterations in the dynamics of the physiological changes associated to aging in young honeybees may significantly impact colony balance in nature.
Topics: Bees; Animals; Juvenile Hormones; Farnesol; Propolis; Resins, Plant; Insecta
PubMed: 38373613
DOI: 10.1016/j.jinsphys.2024.104627 -
Journal of the American Mosquito... Mar 2024Understanding the influence of salinity on the efficacy of mosquito larvicides in brackish water habitats is crucial for effective salt-marsh Aedes taeniorhynchus...
Understanding the influence of salinity on the efficacy of mosquito larvicides in brackish water habitats is crucial for effective salt-marsh Aedes taeniorhynchus control. This study investigated the interactive effects of salinity on the toxicity of 3 commonly used mosquito larvicides: Bacillus thuringiensis israelensis (VectoBac® 12AS), spinosad (Natular® SC), and S-methoprene (Altosid® 12AS) against Ae. taeniorhynchus larvae. Four salinity levels (0 ppt [parts per thousand], 8 ppt, 16 ppt, and 32 ppt) were tested in laboratory bioassays. The results revealed distinct responses of these larvicides to varying salinity levels. VectoBac 12AS displayed consistent efficacy across all salinity levels, indicating its suitability for brackish water habitats. In contrast, Natular 2EC exhibited increased effectiveness with higher salinity, making it a preferable choice for saline environments. Altosid 12AS showed its highest efficacy in freshwater, with reduced effectiveness as salinity increased. These findings underscore the need to consider salinity levels when selecting and applying mosquito larvicides in diverse aquatic habitats. Understanding the complex interplay between salinity and larvicide performance is essential for optimizing mosquito control strategies and mitigating mosquito-borne diseases in various environments.
Topics: Animals; Aedes; Methoprene; Salinity; Bacillus thuringiensis; Larva; Ochlerotatus
PubMed: 38369954
DOI: 10.2987/23-7151 -
The Science of the Total Environment Apr 2024Pentabromodiphenyl ether (BDE-99) and bisphenol A (BPA) are synthetic organic compounds present in several daily use products. Due to their physicochemical properties,...
Pentabromodiphenyl ether (BDE-99) and bisphenol A (BPA) are synthetic organic compounds present in several daily use products. Due to their physicochemical properties, they are ubiquitously present in aquatic ecosystems and considered highly persistent. Recent evidence has confirmed that both emerging compounds are toxic to humans and terrestrial mammals eliciting a wide range of detrimental effects at endocrine and immune levels. However, the ecotoxicological responses that they can trigger in vertebrate marine species have not yet been established. Hence, this study aimed to investigate the ecotoxicological responses of juvenile Sparus aurata upon chronic (28 days) dietary exposure to BDE-99 and BPA (alone and combined) following an integrated multi-biomarker approach that combined fitness indicators (Fulton's K and splenosomatic indexes) with endocrine [cortisol, 17β-estradiol (E2), 11-ketotestosterone (11-KT) concentrations] and immune (peroxidase and antiprotease activities) endpoints in fish plasma, and oxidative stress [superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) activities, and lipid peroxidation (LPO)] endpoints in the fish spleen. The mixture of BDE-99 and BPA yielded the highest IBR index value in both plasma and spleen biomarkers, therefore, suggesting that the effects of these compounds are more severe when they act together. Endocrine biomarkers were the most responsive in the three contaminated treatments. Fitness indicators were not affected by the individual nor the interactive effects of BDE-99 and BPA. These findings highlight the relevance of accounting for the interactive effects of emerging chemical contaminants and integrating responses associated with distinct biological pathways when investigating their impacts on marine life, as such a multi-biomarker approach provides a broader, more realistic and adequate perspective of challenges faced by fish in a contaminated environment.
Topics: Animals; Humans; Sea Bream; Ecosystem; Oxidative Stress; Biomarkers; Mammals; Benzhydryl Compounds; Phenols; Halogenated Diphenyl Ethers
PubMed: 38365038
DOI: 10.1016/j.scitotenv.2024.170989 -
Insect Biochemistry and Molecular... Apr 2024Compounds classified as benzoylphenylurea (BPU), such as diflubenzuron (DFB), are used as insecticides. Although BPU disrupts molting by inhibiting chitin biosynthesis...
Compounds classified as benzoylphenylurea (BPU), such as diflubenzuron (DFB), are used as insecticides. Although BPU disrupts molting by inhibiting chitin biosynthesis and exhibits insecticidal activity, their exact mode of action remains unknown. Since epidermal cells proliferate and morphologically change from squamous to columnar cells during the early stages of insect molting, we speculate that a transition similar to that from epithelium to mesenchyme occurs and that BPU may inhibit this transition. Here, we addressed this possibility. We found that DFB decreases actin expression in insect cells (the tissue cultures of insect integument). Detailed analysis in Schneider S2 cells reveals that DFB inhibits the expression of actin isoforms (Act5C and Act42A) and the Drosophila ortholog of myocardin-related transcription factor (Mrtf), leading to cell growth suppression. Proteomics identified the Drosophila ortholog of prohibitin (Phb1D and Phb2E) as one of the DFB-binding proteins. DFB inhibits the interaction between Phb1D and Phb2E and induces mitochondrial dysfunction. The knock-down of Phb2E suppresses the expression of Act5C, Act42A, and Mrtf, leading to cell growth inhibition. Thus, the disruption of Phb function is a possible novel target of DFB.
Topics: Animals; Diflubenzuron; Actins; Insecticides; Drosophila
PubMed: 38342197
DOI: 10.1016/j.ibmb.2024.104088 -
Molecular and Cellular Endocrinology May 2024Hormones control developmental and physiological processes, often by regulating the expression of multiple genes simultaneously or sequentially. Crosstalk between... (Review)
Review
Hormones control developmental and physiological processes, often by regulating the expression of multiple genes simultaneously or sequentially. Crosstalk between hormones and epigenetics is pivotal to dynamically coordinate this process. Hormonal signals can guide the addition and removal of epigenetic marks, steering gene expression. Conversely, DNA methylation, histone modifications and non-coding RNAs can modulate regional chromatin structure and accessibility and regulate the expression of numerous (hormone-related) genes. Here, we provide a review of the interplay between the classical insect hormones, ecdysteroids and juvenile hormones, and epigenetics. We summarize the mode-of-action and roles of these hormones in post-embryonic development, and provide a general overview of epigenetic mechanisms. We then highlight recent advances on the interactions between these hormonal pathways and epigenetics, and their involvement in development. Furthermore, we give an overview of several 'omics techniques employed in the field. Finally, we discuss which questions remain unanswered and possible avenues for future research.
Topics: Animals; Epigenesis, Genetic; DNA Methylation; Signal Transduction; Insecta; Hormones
PubMed: 38342134
DOI: 10.1016/j.mce.2024.112178 -
Current Biology : CB Feb 2024Juvenile hormone is best known for its role in maintaining juvenile-stage insects in their immature states during postembryonic development. A new study finds an...
Juvenile hormone is best known for its role in maintaining juvenile-stage insects in their immature states during postembryonic development. A new study finds an unexpected role for this signaling lipid in guiding primordial germ cell migration during embryogenesis - possibly an ancestral function of isoprenoid signaling molecules.
Topics: Animals; Juvenile Hormones; Insecta; Cell Movement; Germ Cells
PubMed: 38320477
DOI: 10.1016/j.cub.2023.12.026 -
Neuroscience Mar 2024Aggression is a social behavior that is critical for survival and reproduction. In adults, circulating gonadal hormones, such as androgens, act on neural circuits to...
Aggression is a social behavior that is critical for survival and reproduction. In adults, circulating gonadal hormones, such as androgens, act on neural circuits to modulate aggressive interactions, especially in reproductive contexts. In many species, individuals also demonstrate aggression before reaching gonadal maturation. Adult male song sparrows, Melospiza melodia, breed seasonally but maintain territories year-round. Juvenile (hatch-year) males aggressively compete for territory ownership during their first winter when circulating testosterone is low. Here, we characterized the relationship between the steroid milieu and aggressive behavior in free-living juvenile male song sparrows in winter. We investigated the effect of a 10 min simulated territorial intrusion (STI) on behavior and steroid levels in blood, 10 microdissected brain regions, and four peripheral tissues (liver, pectoral muscle, adrenal glands, and testes). Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we quantified 12 steroids: pregnenolone, progesterone, corticosterone, 11-dehydrocorticosterone, dehydroepiandrosterone, androstenedione, testosterone, 5α-dihydrotestosterone, 17β-estradiol 17α-estradiol, estrone, and estriol. We found that juvenile males are robustly aggressive, like adult males. An STI increases progesterone and corticosterone levels in blood and brain and increases 11-dehydrocorticosterone levels in blood only. Pregnenolone, androgens, and estrogens are generally non-detectable and are not affected by an STI. In peripheral tissues, steroid concentrations are very high in the adrenals. These data suggest that adrenal steroids, such as progesterone and corticosterone, might promote juvenile aggression and that juvenile and adult songbirds might rely on distinct neuroendocrine mechanisms to support similar aggressive behaviors.
Topics: Humans; Animals; Male; Songbirds; Corticosterone; Progesterone; Chromatography, Liquid; Tandem Mass Spectrometry; Testosterone; Androgens; Aggression; Estradiol; Pregnenolone
PubMed: 38301739
DOI: 10.1016/j.neuroscience.2024.01.008 -
Frontiers in Human Neuroscience 2023Thyroid hormones (THs) play a crucial role in regulating various biological processes, particularly the normal development and functioning of the central nervous system...
BACKGROUND
Thyroid hormones (THs) play a crucial role in regulating various biological processes, particularly the normal development and functioning of the central nervous system (CNS). Epilepsy is a prevalent neurological disorder with multiple etiologies. Further in-depth research on the role of thyroid hormones in epilepsy is warranted.
METHODS
Genome-wide association study (GWAS) data for thyroid function and epilepsy were obtained from the ThyroidOmics Consortium and the International League Against Epilepsy (ILAE) Consortium cohort, respectively. A total of five indicators of thyroid function and ten types of epilepsy were included in the analysis. Two-sample Mendelian randomization (MR) analyses were conducted to investigate potential causal relations between thyroid functions and various epilepsies. Multiple testing correction was performed using Bonferroni correction. Heterogeneity was calculated with the Cochran's Q statistic test. Horizontal pleiotropy was evaluated by the MR-Egger regression intercept. The sensitivity was also examined by leave-one-out strategy.
RESULTS
The findings indicated the absence of any causal relationship between abnormalities in thyroid hormone and various types of epilepsy. The study analyzed the odds ratio (OR) between thyroid hormones and various types of epilepsy in five scenarios, including free thyroxine (FT4) on focal epilepsy with hippocampal sclerosis (IVW, OR = 0.9838, = 0.02223), hyperthyroidism on juvenile absence epilepsy (IVW, OR = 0.9952, = 0.03777), hypothyroidism on focal epilepsy with hippocampal sclerosis (IVW, OR = 1.0075, = 0.01951), autoimmune thyroid diseases (AITDs) on generalized epilepsy in all documented cases (weighted mode, OR = 1.0846, = 0.0346) and on childhood absence epilepsy (IVW, OR = 1.0050, = 0.04555). After Bonferroni correction, none of the above results showed statistically significant differences.
CONCLUSION
This study indicates that there is no causal relationship between thyroid-related disorders and various types of epilepsy. Future research should aim to avoid potential confounding factors that might impact the study.
PubMed: 38298204
DOI: 10.3389/fnhum.2023.1295749