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Advances in Experimental Medicine and... Jun 2024Lipids are a diverse group of compounds that play several important roles in insect physiology. Among biological lipids, the fundamental category comprises fatty acyl...
Lipids are a diverse group of compounds that play several important roles in insect physiology. Among biological lipids, the fundamental category comprises fatty acyl structures, with significant members being fatty acids (FAs). They play several crucial functions in insect physiology; they are used as the source of energy for flight and play key roles in the insect immune system. The FAs present in the insect cuticle are known to demonstrate antibacterial and antifungal activity and are considered as potential insecticides. The most abundant family of lipids are the glycerolipids, with numerous cellular functions including storage of energy, structural compartmentation of cells and organelles, and important signaling activities required for regulation of physiological processes (i.e., growth, development, reproduction, diapause, and overwintering). The phospholipids are also highly diversified key components of all cell membranes; they can modify cellular components in response to rapid cold-hardening (RCH), enhancing membrane fluidity and improving survival at low temperatures. The sphingolipids are important structural and signaling bioactive compounds, mostly detected in membranes.Insects are sterol-auxotrophs: they do not have genes, which code enzymes converting farnesyl pyrophosphate to squalene. Similarly, to mammals, the production of steroids in insects is regulated by cytochrome P450 enzymes that convert sterols (mostly cholesterol) to hormonally active steroids. The major molting hormone in insects is 20-hydroxyecdysone, and cholesterol is the required precursor; however, several exemptions from this rule have been noted. This manuscript also reviews the roles of prenol lipids, isoprenoids, lipid vitamins, polyketides, and waxes in the vital processes of insects.
PubMed: 38848019
DOI: 10.1007/5584_2024_805 -
Molecular Ecology Jul 2024Annual rhythms are observed in living organisms with numerous ecological implications. In the zooplanktonic copepod Calanus finmarchicus, such rhythms are crucial...
Annual rhythms are observed in living organisms with numerous ecological implications. In the zooplanktonic copepod Calanus finmarchicus, such rhythms are crucial regarding its phenology, body lipid accumulation, and global carbon storage. Climate change drives annual biological rhythms out of phase with the prevailing environmental conditions with yet unknown but potentially catastrophic consequences. However, the molecular dynamics underlying phenology are still poorly described. In a rhythmic analysis of C. finmarchicus annual gene expression, results reveal that more than 90% of the transcriptome shows significant annual rhythms, with abrupt and dramatic upheaval between the active and diapause life cycle states. This work explores the implication of the circadian clock in the annual timing, which may control epigenetic mechanisms to profoundly modulate gene expression in response to calendar time. Results also suggest an increased light sensitivity during diapause that would ensure the photoperiodic entrainment of the endogenous annual clock.
Topics: Animals; Copepoda; Transcriptome; Diapause; Circadian Clocks; Photoperiod; Seasons; Climate Change; Zooplankton; Circadian Rhythm
PubMed: 38847383
DOI: 10.1111/mec.17425 -
Ecology and Evolution Jun 2024During the winter, animals face limited food availability. Many animals enter dormancy to reduce their winter energy expenditure. Most insects spend the winter in...
During the winter, animals face limited food availability. Many animals enter dormancy to reduce their winter energy expenditure. Most insects spend the winter in diapause, a state of programmed dormancy. It is often assumed that diapausing insects need nutrient stores to fuel their many months of basal metabolism and must grow heavier than their non-diapause-programmed counterparts. However, the extent to which food limitation affects body weight during overwintering preparation as well as the likelihood and duration of diapause remains unclear. We limited the duration of the feeding period and thus the total quantity of food available to diapause-destined larvae of the pupal-diapausing flesh fly, , to test how food limitation affects body weight in the context of diapause programming. We also tested the extent to which food deprivation and body weight affect the likelihood and duration of diapause. We hypothesized that diapause-destined larvae grow more quickly and pupariate at a heavier body weight than non-diapause larvae. We also hypothesized that body weight is more dramatically reduced by food limitations when a larva is programmed for diapause. Finally, we hypothesized that larvae with lighter body weight (i.e., food limited) are less likely to enter pupal diapause and also stay in diapause for a shorter duration than heavier, well-fed, individuals. Contrary to our hypotheses that diapausing insects are heavier than their non-diapausing counterparts, we found diapausing pupae weighed less than non-diapausing pupae, especially when larvae received limited food. We found light pupae did not abort their diapause program. In both diapausing and non-diapausing pupae, body weight was positively correlated with simulated winter survival. However, above a weight threshold, body weight no longer affected simulated winter survival in diapausing pupae. Contrary to our predictions and the general consensus in much of the diapause literature, we also found that lighter pupae stayed in diapause longer than heavier pupae. Overall, our results challenge the precept that body weight and diapause are positively associated. The relationship between body weight and diapause is complex and may be affected by the availability of food before and after winter, the availability of high-quality overwintering sites, and the life history of a particular insect.
PubMed: 38835525
DOI: 10.1002/ece3.11511 -
Environmental Entomology Jun 2024The life history aspects of dormancy of the weevil Anthonomus rufipennis LeConte (Coleoptera: Curculionidae) were studied a 57-month period in a seasonally dry tropical...
The life history aspects of dormancy of the weevil Anthonomus rufipennis LeConte (Coleoptera: Curculionidae) were studied a 57-month period in a seasonally dry tropical forest of central Mexico. Weevil populations and their physiological status were monitored on both the reproductive host tree, Senna polyantha (Collad.) H.S: Irwin & Barneby (Fabales: Fabaceae) and the highly favored refuge host, Tillandsia recurvata L. (Poales: Bromeliaceae) or "ball moss." During the dry season, weevils were only found on the refuge host with a mean total density of 1.014 ± 2.532 individuals/ball moss (N = 1,681). Weevil densities on T. recurvata between early and late dry seasons were not significantly different, suggesting that dry season survival was relatively high. Weevils collected during these seasons revealed little reproductive development and relatively high-fat accumulation in both sexes. During 5 of 6 yr, densities of the weevils in T. recurvata dropped significantly during the early rainy seasons, when the reproductive host trees leafed out and began producing oviposition sites (flower buds). At this time, more males than females initially moved to vegetative trees and showed significant signs of reproductive development. Recolonization of ball moss by weevils began during the late rainy season when oviposition sites (flower buds) were still available. A proportion of the weevils remained on the reproductive host, suggesting that A. rufipennis is facultatively multivoltine. The methodologies and results of the study can serve as a model system for future studies of the dormancy of other insects in dry tropical forests and provide insight into the dormancy of other anthonomine weevils of economic importance.
PubMed: 38822449
DOI: 10.1093/ee/nvae054 -
Comparative Biochemistry and... Sep 2024The northern house mosquito, Culex pipiens, employs diapause as an essential survival strategy during winter, inducing important phenotypic changes such as enhanced...
The northern house mosquito, Culex pipiens, employs diapause as an essential survival strategy during winter, inducing important phenotypic changes such as enhanced stress tolerance, lipid accumulation, and extended longevity. During diapause, the cessation of reproductive development represents another distinctive phenotypic change, underlining the need for adjusted modulation of gene expressions within the ovary. Although considerable advancements in screening gene expression profiles in diapausing and non-diapausing mosquitoes, there remains a gap in tissue-specific transcriptomic profiling that could elucidate the complicated formation of diverse diapause features in Cx. pipiens. Here, we filled this gap by utilizing RNA sequencing, providing a detailed examination of gene expression patterns in the fat body and ovary during diapause compared to non-diapause conditions. Functional annotation of upregulated genes identified associations with carbohydrate metabolism, stress tolerance, immunity, and epigenetic regulation. The validation of candidate genes using quantitative real-time PCR verified the differentially expressed genes identified in diapausing mosquitoes. Our findings contribute novel insights into potential regulators during diapause in Cx. pipiens, thereby opening possible avenues for developing innovative vector control strategies.
Topics: Animals; Culex; Female; Fat Body; Ovary; Gene Expression Profiling; Diapause, Insect; Metabolic Networks and Pathways; Transcriptome; Organ Specificity; Insect Proteins
PubMed: 38820803
DOI: 10.1016/j.cbd.2024.101260 -
Scientific Reports May 2024Loss of the tumor suppressor PTEN homolog daf-18 in Caenorhabditis elegans (C. elegans) triggers diapause cell division during L1 arrest. While prior studies have delved...
Loss of the tumor suppressor PTEN homolog daf-18 in Caenorhabditis elegans (C. elegans) triggers diapause cell division during L1 arrest. While prior studies have delved into established pathways, our investigation takes an innovative route. Through forward genetic screening in C. elegans, we pinpoint a new player, F12E12.11, regulated by daf-18, impacting cell proliferation independently of PTEN's typical phosphatase activity. F12E12.11 is an ortholog of human estradiol 17-beta-dehydrogenase 8 (HSD17B8), which converts estradiol to estrone through its NAD-dependent 17-beta-hydroxysteroid dehydrogenase activity. We found that PTEN engages in a physical interplay with HSD17B8, introducing a distinctive suppression mechanism. The reduction in estrone levels and accumulation of estradiol may arrest tumor cells in the G2/M phase of the cell cycle through MAPK/ERK. Our study illuminates an unconventional protein interplay, providing insights into how PTEN modulates tumor suppression by restraining cell division through intricate molecular interactions.
Topics: PTEN Phosphohydrolase; Animals; Cell Proliferation; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Humans; 17-Hydroxysteroid Dehydrogenases; Estradiol; Estrone
PubMed: 38811827
DOI: 10.1038/s41598-024-63052-5 -
Lipid composition differs in diapause and nondiapause states of spotted stem borer, Chilo partellus.Comparative Biochemistry and... May 2024Spotted stem borer, Chilo partellus, undergoes larval diapause (hibernation and aestivation), and depends on the food reserve accumulated during feeding stage for its...
Spotted stem borer, Chilo partellus, undergoes larval diapause (hibernation and aestivation), and depends on the food reserve accumulated during feeding stage for its survival. Lipids are the primary source of energy during diapause, and essential for different cellular, biochemical and physiological functions. However, there is no information on lipid and lipophilic compound contents during different stages of hibernation, aestivation and nondiapause in C. partellus. Thus, we compared the concentration and composition of lipids in pre-diapause, diapause and post-diapause stages of hibernation and aestivation with nondiapause stages of C. partellus. The studies revealed significant differences in total lipids and various lipophilic compounds during different stages of diapause as compared to nondiapause C. partellus. The total lipids were significantly lower during diapause stage of aestivation and hibernation as compared to nondiapause larvae. Further, the linoleic acid, Methyl 3-methoxytetradecanoate, and l-(+)-Ascorbic acid 2,6-dihexadecanoate were significantly lower, and oleic and palmitoleic acids greater during pre-diapause and diapause stages of hibernation and aestivation as compared to nondiapause larvae. The cholesterol content was significantly greater during pre-diapause stage of hibernation, and diapause and post-diapause stages of aestivation as compared to nondiapause stages. The unsaturation ratio was significantly higher in the pre-diapause and diapause stages and lower in post-diapause stage of aestivation than the hibernation and nondiapause states. This study provides insights on differential lipid profiles during different phases of diapause, which could be useful for further understanding biochemical and physiological cross-talk, and develop target-specific technologies for the management of C. partellus.
PubMed: 38810773
DOI: 10.1016/j.cbpb.2024.110996 -
Cell Jun 2024Suspended animation states allow organisms to survive extreme environments. The African turquoise killifish has evolved diapause as a form of suspended development to...
Suspended animation states allow organisms to survive extreme environments. The African turquoise killifish has evolved diapause as a form of suspended development to survive a complete drought. However, the mechanisms underlying the evolution of extreme survival states are unknown. To understand diapause evolution, we performed integrative multi-omics (gene expression, chromatin accessibility, and lipidomics) in the embryos of multiple killifish species. We find that diapause evolved by a recent remodeling of regulatory elements at very ancient gene duplicates (paralogs) present in all vertebrates. CRISPR-Cas9-based perturbations identify the transcription factors REST/NRSF and FOXOs as critical for the diapause gene expression program, including genes involved in lipid metabolism. Indeed, diapause shows a distinct lipid profile, with an increase in triglycerides with very-long-chain fatty acids. Our work suggests a mechanism for the evolution of complex adaptations and offers strategies to promote long-term survival by activating suspended animation programs in other species.
Topics: Animals; Diapause; Biological Evolution; Fundulidae; Lipid Metabolism; Killifishes; Embryo, Nonmammalian; Gene Expression Regulation, Developmental
PubMed: 38810644
DOI: 10.1016/j.cell.2024.04.048 -
Journal of Insect Science (Online) May 2024Aspongopus chinensis Dallas, 1851 (Hemiptera: Dinidoridae), an edible and medicinal insect, usually found in China and Southeast Asia, offers substantial potential for...
Aspongopus chinensis Dallas, 1851 (Hemiptera: Dinidoridae), an edible and medicinal insect, usually found in China and Southeast Asia, offers substantial potential for various applications. The reproductive cycle of this particular insect occurs annually because of reproductive diapause, leading to inadequate utilization of available natural resources. Despite its considerable ecological importance, the precise mechanisms underlying diapause in A. chinensis are not yet well understood. In this study, we conducted an analysis of comparing the microRNA (miRNA) regulation in the diapause and non-diapause gonads of A. chinensis and identified 303 differentially expressed miRNAs, among which, compared with the diapause group, 76 miRNAs were upregulated and 227 miRNAs downregulated. The results, regarding the Enrichment analysis of miRNA-targeted genes, showed their involvement in several essential biological processes, such as lipid anabolism, energy metabolism, and gonadal growth. Interestingly, we observed that the ATP-binding cassette pathway is the only enriched pathway, demonstrating the capability of these targeted miRNAs to regulate the reproductive diapause of A. chinensis through the above essential pathway. The current study provided the role of gonadal miRNA expression in the control of reproductive diapause in A. chinensis, the specific regulatory mechanism behind this event remained unknown and needed more investigation.
Topics: Animals; MicroRNAs; Hemiptera; Diapause, Insect; Gonads; Female; Male; Reproduction
PubMed: 38809688
DOI: 10.1093/jisesa/ieae021 -
Scientific Reports May 2024Winter diapause consists of cessation of development that allows individuals to survive unfavourable conditions. Winter diapause may bear various costs and questions...
Winter diapause consists of cessation of development that allows individuals to survive unfavourable conditions. Winter diapause may bear various costs and questions have been raised about the evolutionary mechanisms maintaining facultative diapause. Here, we explored to what extent a facultative winter diapause affects life-history traits and the transcriptome in the damselfly Ischnura elegans, and whether these effects were latitude-specific. We collected adult females at central and high latitudes and raised their larvae in growth chambers. Larvae were split into a non-diapausing and post-winter (diapausing) cohort, were phenotyped and collected for a gene expression analysis. At the phenotypic level, we found no difference in survival between the two cohorts, and the post-winter cohort was larger and heavier than the non-winter cohort. These effects were mostly independent of the latitude of origin. At the transcriptomic level, wintering affected gene expression with a small fraction of genes significantly overlapping across latitudes, especially those related to morphogenesis. In conclusion, we found clear effects of diapause on the phenotype but little evidence for latitudinal-specific effects of diapause. Our results showed a shared transcriptomic basis underpinning diapause demonstrated, here, at the intraspecific level and supported the idea of evolutionary convergence of the response to diapause across organisms.
Topics: Animals; Odonata; Transcriptome; Seasons; Female; Larva; Phenotype; Diapause, Insect; Diapause; Genetic Fitness
PubMed: 38806592
DOI: 10.1038/s41598-024-63066-z