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Science (New York, N.Y.) Sep 2022In most organisms, reproduction is correlated with shorter life span. However, the reproductive queen in eusocial insects exhibits a much longer life span than that of...
In most organisms, reproduction is correlated with shorter life span. However, the reproductive queen in eusocial insects exhibits a much longer life span than that of workers. In ants, when the queen dies, workers can undergo an adult caste switch to reproductive pseudo-queens (gamergates), exhibiting a five-times prolonged life span. To explore the relation between reproduction and longevity, we compared gene expression during caste switching. Insulin expression is increased in the gamergate brain that correlates with increased lipid synthesis and production of vitellogenin in the fat body, both transported to the egg. This results from activation of the mitogen-activated protein kinase (MAPK) branch of the insulin signaling pathway. By contrast, the production in the gamergate developing ovary of anti-insulin Imp-L2 leads to decreased signaling of the AKT/forkhead box O (FOXO) branch in the fat body, which is consistent with their extended longevity.
Topics: Animals; Ants; Female; Insulin; Longevity; Mitogen-Activated Protein Kinase Kinases; Ovary; Reproduction; Signal Transduction; Vitellogenins
PubMed: 36048960
DOI: 10.1126/science.abm8767 -
Insects Jun 2021The biodiversity of useful organisms, e.g., insects, decreases due to many environmental factors and increasing anthropopressure. Multifunctional tissues, such as the... (Review)
Review
The biodiversity of useful organisms, e.g., insects, decreases due to many environmental factors and increasing anthropopressure. Multifunctional tissues, such as the fat body, are key elements in the proper functioning of invertebrate organisms and resistance factors. The fat body is the center of metabolism, integrating signals, controlling molting and metamorphosis, and synthesizing hormones that control the functioning of the whole body and the synthesis of immune system proteins. In fat body cells, lipids, carbohydrates and proteins are the substrates and products of many pathways that can be used for energy production, accumulate as reserves, and mobilize at the appropriate stage of life (diapause, metamorphosis, flight), determining the survival of an individual. The fat body is the main tissue responsible for innate and acquired humoral immunity. The tissue produces bactericidal proteins and polypeptides, i.e., lysozyme. The fat body is also important in the early stages of an insect's life due to the production of vitellogenin, the yolk protein needed for the development of oocytes. Although a lot of information is available on its structure and biochemistry, the fat body is an interesting research topic on which much is still to be discovered.
PubMed: 34208190
DOI: 10.3390/insects12060547 -
MBio Feb 2023Integration between animal reproduction and symbiont inheritance is fundamental in symbiosis biology, but the underlying molecular mechanisms are largely unknown....
Integration between animal reproduction and symbiont inheritance is fundamental in symbiosis biology, but the underlying molecular mechanisms are largely unknown. Vitellogenin (Vg) is critical for oogenesis, and it is also a pathogen pattern recognition molecule in some animals. Previous studies have shown that Vg is involved in the regulation of symbiont abundance and transmission. However, the mechanisms by which an insect and its symbiont contribute to the function of Vg and how Vg impacts the persistence of insect-microbe symbiosis remain largely unclear. Symbionts are transovarially transmitted via maternal inheritance of the bacteriocytes in the whitefly Bemisia tabaci. Surprisingly, Vg is localized in bacteriocytes of whiteflies. Vg could be synthesized in whitefly bacteriocytes by the gene expressed in these cells or exported into bacteriocytes from hemolymph via the Vg receptor. We further found that the juvenile hormone and " Portiera aleyrodidarum" (here termed ) control the level and localization of Vg in whiteflies. Immunocapture PCR revealed interactions between Vg and . Suppressing Vg expression reduced abundance as well as whitefly oogenesis and fecundity. Thus, we reveal that Vg facilitated the persistence of whitefly-bacteriocyte symbiont associations. This study will provide insight into the key role of Vg in the coevolution of insect reproduction and symbiont inheritance. Intracellular heritable symbionts have been incorporated into insect reproductive and developmental biology by various mechanisms. All Bemisia tabaci species harbor the obligate symbiont in specialized insect cells called bacteriocytes. We report that the whitefly juvenile hormone and determined vitellogenin (Vg) localization in bacteriocytes of whiteflies. In turn, Vg affected whitefly fecundity as well as fitness and transmission of the symbiont. Our findings show that Vg, a multifunctional protein, is indispensable for symbiont integration into the reproduction and development of insects. This reflects the outcome of long-term coevolution of the insect-microbe symbiosis.
Topics: Animals; Vitellogenins; Hemiptera; Symbiosis; Polymerase Chain Reaction
PubMed: 36692332
DOI: 10.1128/mbio.02990-22 -
Physiological Research Dec 2023Insect vitellogenins are an intriguing class of complex proteins. They primarily serve as a source of energy for the developing embryo in insect eggs. Vitellogenesis is... (Review)
Review
Insect vitellogenins are an intriguing class of complex proteins. They primarily serve as a source of energy for the developing embryo in insect eggs. Vitellogenesis is a complex hormonally and neurally controlled process that command synthesis of vitellogenin molecules and ensures their transport from the female fat bodies or ovarial cells into eggs. The representatives of all insect hormones such as juvenile hormones, ecdysteroids, and neurohormones participate in vitellogenesis, but juvenile hormones (most insect species) and ecdysteroids (mostly Diptera) play the most important roles in the process. Strikingly, not only insect females, but also males have been reported to synthesize vitellogenins indicating their further utility in the insect body. Indeed, it has recently been found that vitellogenins perform a variety of biological functions in the insect body. They participate in defense reactions against entomopathogens such as nematodes, fungi, and bacteria, as well as against venoms such as the honeybee Apis mellifera venom. Interestingly, vitellogenins are also present in the venom of the honeybee itself, albeit their exact role is unknown; they most likely increase the efficacy of the venom in the victim's body. Within the bee's body vitellogenins contribute to the lifespan regulation as anti-aging factor acting under tight social interactions and hormonal control. The current minireview covers all of these functions of vitellogenins and portrays them as biologically active substances that play a variety of significant roles in both insect females and males, and not only acting as passive energy sources for developing embryo.
Topics: Male; Female; Animals; Vitellogenins; Ecdysteroids; Juvenile Hormones; Ovary; Insecta
PubMed: 38165752
DOI: 10.33549/physiolres.935221 -
Frontiers in Cell and Developmental... 2020Vitellogenesis is pre-requisite to insect egg production and embryonic development after oviposition. During insect vitellogenesis, the yolk protein precursor... (Review)
Review
Vitellogenesis is pre-requisite to insect egg production and embryonic development after oviposition. During insect vitellogenesis, the yolk protein precursor vitellogenin (Vg) is mainly synthesized in the fat body, transported by the hemolymph through the intercellular spaces (known as patency) in the follicular epithelium to reach the membrane of maturing oocytes, and sequestered into the maturing oocytes via receptor-mediated endocytosis. Insect vitellogenesis is governed by two critical hormones, the sesquiterpenoid juvenile hormone (JH) and the ecdysteriod 20-hydroxyecdysone (20E). JH acts as the principal gonadotropic hormone to stimulate vitellogenesis in basal hemimetabolous and most holometabolous insects. 20E is critical for vitellogenesis in some hymenopterans, lepidopterans and dipterans. Furthermore, microRNA (miRNA) and nutritional (amino acid/Target of Rapamycin and insulin) pathways interplay with JH and 20E signaling cascades to control insect vitellogenesis. Revealing the regulatory mechanisms underlying insect vitellogenesis is critical for understanding insect reproduction and helpful for developing new strategies of insect pest control. Here, we outline the recent research progress in the molecular action of gonadotropic JH and 20E along with the role of miRNA and nutritional sensor in regulating insect vitellogenesis. We highlight the advancements in the regulatory mechanisms of insect vitellogenesis by the coordination of hormone, miRNA and nutritional signaling pathways.
PubMed: 33634094
DOI: 10.3389/fcell.2020.593613 -
Ecology and Evolution Jul 2021Vitellogenin (Vg), a storage protein, has been significantly studied for its egg yolk precursor role in oviparous animals. Recent studies found that vitellogenin and its...
Vitellogenin (Vg), a storage protein, has been significantly studied for its egg yolk precursor role in oviparous animals. Recent studies found that vitellogenin and its Vg-like homologs were fundamentally involved in many other biological processes in social insects such as female caste differences and oxidative stress resilience. In this study, we conducted the first large-scale molecular evolutionary analyses of vitellogenin coding genes () and genes of bumble bees, a primitively eusocial insect belonging to the genus Bombus. We obtained sequences for each of the four genes (, , , and ) from 27 bumble bee genomes (nine were newly sequenced in this study), and sequences from the two closest clades of , including five species and five . Our molecular evolutionary analyses show that in bumble bee, the conventional experienced strong positive selection, while the genes showed overall relaxation of purifying selection. In and however, all four genes were found under purifying selection. Furthermore, the conventional showed signs of strong positive selection in most subgenera in , apart from the obligate parasitic subgenus which has no caste differentiation. Together, these results indicate that the conventional , a key pleiotropic gene in social insects, is the most rapidly evolving copy, potentially due to its multiple known social functions for both worker and queen castes. This study shows that concerted evolution and purifying selection shaped the evolution of the gene family following their ancient gene duplication and may be the leading forces behind the evolution of new potential protein function enabling functional social pleiotropy.
PubMed: 34257940
DOI: 10.1002/ece3.7736 -
Journal of Insect Science (Online) Nov 2020Oviposition-related genes have remained a consistent focus of insect molecular biology. Previous research has gradually clarified our mechanistic understanding of... (Review)
Review
Oviposition-related genes have remained a consistent focus of insect molecular biology. Previous research has gradually clarified our mechanistic understanding of oviposition-related genes, including those related to oviposition-gland-related genes, oogenesis-related genes, oviposition-site-selection-related genes, and genes related to ovulation and hatching. Moreover, some of this research has revealed how the expression of single oviposition-related genes affects the expression of related genes, and more importantly, how individual node genes function to link the expression of upstream and downstream genes. However, the research to date is not sufficient to completely explain the overall interactions among the genes of the insect oviposition system. Through a literature review of a large number of studies, this review provides references for future research on oviposition-related genes in insects and the use of RNAi or CRISPR/Cas9 technology to verify the functions of oviposition-related genes and to prevent and control harmful insects.
Topics: Animals; CRISPR-Cas Systems; Egg Proteins; Female; Gene Expression; Genes, Insect; Insect Control; Insecta; Oogenesis; Oviposition; RNA Interference; Receptors, Cell Surface; Vitellogenins
PubMed: 33367730
DOI: 10.1093/jisesa/ieaa137 -
Nutrients Oct 2015Vitellogenin (Vtg), the major egg yolk precursor protein, is traditionally thought to provide protein- and lipid-rich nutrients for developing embryos and larvae.... (Review)
Review
Vitellogenin (Vtg), the major egg yolk precursor protein, is traditionally thought to provide protein- and lipid-rich nutrients for developing embryos and larvae. However, the roles of Vtg as well as its derived yolk proteins lipovitellin (Lv) and phosvitin (Pv) extend beyond nutritional functions. Accumulating data have demonstrated that Vtg, Lv and Pv participate in host innate immune defense with multifaceted functions. They can all act as multivalent pattern recognition receptors capable of identifying invading microbes. Vtg and Pv can also act as immune effectors capable of killing bacteria and virus. Moreover, Vtg and Lv are shown to possess phagocytosis-promoting activity as opsonins. In addition to these immune-relevant functions, Vtg and Pv are found to have antioxidant activity, which is able to protect the host from oxidant stress. These non-nutritional functions clearly deepen our understanding of the physiological roles of the molecules, and at the same time, provide a sound basis for potential application of the molecules in human health.
Topics: Animals; Antioxidants; Bacteria; Egg Proteins; Fishes; Phosvitin; Receptors, Pattern Recognition; Viruses; Vitellogenins
PubMed: 26506386
DOI: 10.3390/nu7105432 -
Frontiers in Physiology 2019Vitellogenins are a family of yolk proteins that are by far the most abundant among oviparous animals. In the model nematode , the 6 vitellogenins are among the most... (Review)
Review
Vitellogenins are a family of yolk proteins that are by far the most abundant among oviparous animals. In the model nematode , the 6 vitellogenins are among the most highly expressed genes in the adult hermaphrodite intestine, which produces copious yolk to provision eggs. In this article we review what is known about the vitellogenin genes and proteins in , in comparison with vitellogenins in other taxa. We argue that the primary purpose of abundant vitellogenesis in is to support post-embryonic development and fertility, rather than embryogenesis, especially in harsh environments. Increasing vitellogenin provisioning underlies several post-embryonic phenotypic alterations associated with advancing maternal age, demonstrating that vitellogenins can act as an intergenerational signal mediating the influence of parental physiology on progeny. We also review what is known about vitellogenin regulation - how tissue-, sex- and stage-specificity of expression is achieved, how vitellogenins are regulated by major signaling pathways, how vitellogenin expression is affected by extra-intestinal tissues and how environmental experience affects vitellogenesis. Lastly, we speculate whether vitellogenins may play other roles in worm physiology.
PubMed: 31551797
DOI: 10.3389/fphys.2019.01067 -
Ecotoxicology and Environmental Safety Sep 2022Bactrocera tau (Walker) is a fly pest species mainly distributed in Southeast Asia and the South Pacific; it causes substantial ecological and economic issues because of...
Bactrocera tau (Walker) is a fly pest species mainly distributed in Southeast Asia and the South Pacific; it causes substantial ecological and economic issues because of its destructiveness and rapid reproduction. Chemical sterilization technology can reduce the use of insecticides and is widely applied for insect pest control. In this study, the sterilization efficacy of varying concentrations of four chemosterilants, namely, hexamethylphosphoramide (HMPA), CSII Aqua, 5-fluorouracil (5-FU), and colchicine, on adult pumpkin flies was investigated. The results indicated that a solution of 0.03% HMPA had the highest sterilization efficacy. When the number of sterile males was equal to or exceeded 20 times that of untreated males, the hatching rate of offspring eggs was less than 10%. Chemosterilant treatment significantly altered the levels of acid phosphatase (ACP), alkaline phosphatase (AKP), and B. tau vitellogenin (BtVg); these substances have an important impact on reproductive development. The treatment also decreased the size of the reproductive organs (i.e., testes and ovaries). Our results suggest that 0.03% HMPA has unique sterilization properties and may represent a new chemical agent for the control of B. tau populations in agricultural settings.
Topics: Animals; Chemosterilants; Hempa; Insect Control; Insecta; Male; Tephritidae
PubMed: 36037635
DOI: 10.1016/j.ecoenv.2022.114028