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Introduction Dichlorodiphenyltrichloroethane (DDT) is a lipophilic organochlorine pollutant that is listed under the Stockholm Convention, with the objective to eliminate its use so as to protect human health and the [...], Background: The organochlorine dichlorodiphenyltrichloroethane (DDT) is banned worldwide owing to its negative health effects. It is exceptionally used as an insecticide for malaria control. Exposure occurs in regions where DDT is applied, as well as in the Arctic, where its endocrine disrupting metabolite, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) accumulates in marine mammals and fish. DDT and p,p'- DDE exposures are linked to birth defects, infertility, cancer, and neurodevelopmental delays. Of particular concern is the potential of DDT use to impact the health of generations to come via the heritable sperm epigenome. Objectives: The objective of this study was to assess the sperm epigenome in relation to p,p'-DDE serum levels between geographically diverse populations. Methods: In the Limpopo Province of South Africa, we recruited 247 VhaVenda South African men and selected 50 paired blood serum and semen samples, and 47 Greenlandic Inuit blood and semen paired samples were selected from a total of 193 samples from the biobank of the INUENDO cohort, an EU Fifth Framework Programme Research and Development project. Sample selection was based on obtaining a range of p,p'- DDE serum levels (mean = 870.734 [+ or -] 134.030 ng/mL). We assessed the sperm epigenome in relation to serump,p'-DDE levels using MethylC-Capture-sequencing (MCCseq) and chromatin immunoprecipitation followed by sequencing (ChIP-seq). We identified genomic regions with altered DNA methylation (DNAme) and differential enrichment of histone H3 lysine 4 trimethylation (H3K4me3) in sperm. Results: Differences in DNAme and H3K4me3 enrichment were identified at transposable elements and regulatory regions involved in fertility, disease, development, and neurofunction. A subset of regions with sperm DNAme and H3K4me3 that differed between exposure groups was predicted to persist in the preimplantation embryo and to be associated with embryonic gene expression. Discussion: These findings suggest that DDT and p,p'-DDE exposure impacts the sperm epigenome in a dose-response- like manner and may negatively impact the health of future generations through epigenetic mechanisms. Confounding factors, such as other environmental exposures, genetic diversity, and selection bias, cannot be ruled out. https://doi.org/10.1289/EHP12013

BACKGROUND: Integrated Pest Management (IPM) seeks to combine multiple management strategies for optimal pest control. One method that is successfully employed in IPM is the use of beneficial organisms. However, in severe circumstances when pest insects exceed threshold limits, insecticides may still need to be implemented. Thus, understanding the effects of insecticides on biocontrol agents, such as parasitoid wasps, is paramount to ensure sustainable agroecosystems. Sublethal effects of the bioinsecticide spinosyn, a mixture of the bacterial Saccharopolyspora spinosa (Mertz and Yao) fermentation products spinosyn A and D, on eggs of Trichoplusia ni (Hübner), a cruciferous crop pest, and its egg parasitoid Trichogramma brassicae (Bezdenko) was investigated. RESULTS: The LC50 for spinosyn A and D (dissolved in ethanol) on T. ni eggs is 54 ng mL−1. Transcriptomics on caterpillars (1st and 3rd instars) that hatched from eggs treated with sublethal concentrations of spinosyn identified the upregulation of several genes encoding proteins that may be involved in insecticide resistance including detoxification enzymes, such as cytochrome P450s, glutathione S‐transferases and esterases. Sublethal T. ni egg treatments did not affect parasitoid emergence, however, there was a marked increase in the size of T. brassicae hind tibia and wings that emerged from spinosyn‐treated eggs. CONCLUSIONS: For the caterpillar, treatment of eggs with sublethal concentrations of spinosyn may induce insecticide resistance mechanisms. For the parasitoids, their increased size when reared in spinosyn‐treated eggs suggests that the emerged wasps may have higher performance. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In wounded Arabidopsis thaliana leaves, four 13S-lipoxygenases (AtLOX2, AtLOX3, AtLOX4, AtLOX6) act in a hierarchical manner to contribute to the jasmonate burst. This leads to defense responses with LOX2 playing an important role in plant resistance against caterpillar herb-ivory. In this study, we sought to characterize the impact of AtLOX2 on wound-induced phytohormonal and transcriptional responses to foliar mechanical damage using wildtype (WT) and lox2 mutant plants. Compared with WT, the lox2 mutant had higher constitutive levels of the phytohormone salicylic acid (SA) and enhanced expression of SA-responsive genes. This suggests that AtLOX2 may be involved in the biosynthesis of jasmonates that are involved in the antagonism of SA biosynthesis. As expected, the jasmonate burst in response to wounding was dampened in lox2 plants. Generally, 1 h after wounding, genes linked to jasmonate biosynthesis, jasmonate signaling attenuation and abscisic acid-responsive genes, which are primarily involved in wound sealing and healing, were differentially regulated between WT and lox2 mutants. Twelve h after wounding, WT plants showed stronger expression of genes associated with plant protection against insect herbivory. This study highlights the dynamic nature of jasmonate-responsive gene expression and the contribution of AtLOX2 to this pathway and plant resistance against insects. [ABSTRACT FROM AUTHOR]

Hibernators suppress physiological processes when expressing torpor, yet little is known about the effects of torpor on male reproductive physiology. Studies of hibernating mammals suggest that deep torpor negatively impacts spermatogenesis and that transitions between torpor and euthermic arousals increase cellular oxidative stress, with potentially damaging effects on sperm. Here, we hypothesize that variation in torpor expression affects the reproductive readiness of hibernators by impacting their sperm production. To test this, we examined the relationship between torpor expression and spermatogenesis in captive eastern chipmunks (Tamias striatus). We determined torpor depth with temperature data loggers and assessed its relationship with spermatogenesis by examining spermatogenic progression, cell division, sperm counts, sperm maturity, and DNA damage. We show that deep hibernators (high levels of torpor) largely halted spermatogenesis in late hibernation in comparison with shallow hibernators (low levels of torpor), where ongoing spermatogenesis was observed. Despite these differences in spermatogenic state during hibernation, spermatogenic progression, sperm numbers, and maturity did not differ in spring, potentially reflecting similar degrees of reproductive readiness. Interestingly, shallow hibernators exhibited higher rates of DNA damage in spermatogenic cells during hibernation, with this trend reversing in spring. Our results thus indicate that once heterothermy is terminated, deep hibernators resume spermatogenesis but are characterized by higher rates of DNA damage in spermatogenic cells at the seasonal stage when spring mating commences. Therefore, our study confirmed posthibernation recovery of sperm production but also a potential impact of deep torpor expression during winter on DNA damage in spring. [ABSTRACT FROM AUTHOR]