-
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 -
PeerJ 2023The crown-of-thorns starfish (COTS; ) is a slow-moving corallivore protected by an extensive array of long, sharp toxic spines. Envenomation can result in nausea,...
BACKGROUND
The crown-of-thorns starfish (COTS; ) is a slow-moving corallivore protected by an extensive array of long, sharp toxic spines. Envenomation can result in nausea, numbness, vomiting, joint aches and sometimes paralysis. Small molecule saponins and the plancitoxin proteins have been implicated in COTS toxicity.
METHODS
Brine shrimp lethality assays were used to confirm the secretion of spine toxin biomolecules. Histological analysis, followed by spine-derived proteomics helped to explain the source and identity of proteins, while quantitative RNA-sequencing and phylogeny confirmed target gene expression and relative conservation, respectively.
RESULTS
We demonstrate the lethality of COTS spine secreted biomolecules on brine shrimp, including significant toxicity using aboral spine semi-purifications of >10 kDa ( > 0.05, 9.82 µg/ml), supporting the presence of secreted proteins as toxins. Ultrastructure observations of the COTS aboral spine showed the presence of pores that could facilitate the distribution of secreted proteins. Subsequent purification and mass spectrometry analysis of spine-derived proteins identified numerous secretory proteins, including plancitoxins, as well as those with relatively high gene expression in spines, including phospholipase A2, protease inhibitor 16-like protein, ependymin-related proteins and those uncharacterized. Some secretory proteins (, vitellogenin and deleted in malignant brain tumor protein 1) were not highly expressed in spine tissue, yet the spine may serve as a storage or release site. This study contributes to our understanding of the COTS through functional, ultrastructural and proteomic analysis of aboral spines.
Topics: Animals; Proteomics; Artemia; Arthralgia; Biological Assay; Biological Transport
PubMed: 37637177
DOI: 10.7717/peerj.15689 -
PLoS Pathogens Dec 2023Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming...
Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming industry. Nosema bombycis is a typical microsporidium that infects multiple lepidopteran insects via fecal-oral and transovarial transmission (TOT); however, the underlying TOT processes and mechanisms remain unknown. Here, we characterized the TOT process and identified key factors enabling N. bombycis to invade the ovariole and oocyte of silkworm Bombyx mori. We found that the parasites commenced with TOT at the early pupal stage when ovarioles penetrated the ovary wall and were exposed to the hemolymph. Subsequently, the parasites in hemolymph and hemolymph cells firstly infiltrated the ovariole sheath, from where they invaded the oocyte via two routes: (I) infecting follicular cells, thereby penetrating oocytes after proliferation, and (II) infecting nurse cells, thus entering oocytes following replication. In follicle and nurse cells, the parasites restructured and built large vacuoles to deliver themselves into the oocyte. In the whole process, the parasites were coated with B. mori vitellogenin (BmVg) on their surfaces. To investigate the BmVg effects on TOT, we suppressed its expression and found a dramatic decrease of pathogen load in both ovarioles and eggs, suggesting that BmVg plays a crucial role in the TOT. Thereby, we identified the BmVg domains and parasite spore wall proteins (SWPs) mediating the interaction, and demonstrated that the von Willebrand domain (VWD) interacted with SWP12, SWP26 and SWP30, and the unknown function domain (DUF1943) bound with the SWP30. When disrupting these interactions, we found significant reductions of the pathogen load in both ovarioles and eggs, suggesting that the interplays between BmVg and SWPs were vital for the TOT. In conclusion, our study has elucidated key aspects about the microsporidian TOT and revealed the key factors for understanding the molecular mechanisms underlying this transmission.
Topics: Animals; Humans; Vitellogenins; Spores, Fungal; Nosema; Bombyx
PubMed: 38060601
DOI: 10.1371/journal.ppat.1011859 -
Environmental Pollution (Barking, Essex... Oct 20234-Methylbenzylidene camphor (4-MBC), an emerging contaminant, is a widely-used ultraviolet (UV) filter incorporated into cosmetics because it protects the skin from UV...
4-Methylbenzylidene camphor (4-MBC), an emerging contaminant, is a widely-used ultraviolet (UV) filter incorporated into cosmetics because it protects the skin from UV rays and counters photo-oxidation. Despite the well-established estrogenic activity of 4-MBC, the link between this activity and its effects on neurobehavior and the liver remains unknown. Thus, we exposed zebrafish larvae to environmentally relevant concentrations of 4-MBC with 1.39, 4.17, 12.5 and 15.4 μg/mL from 3 to 5 days postfertilization. We found that 4-MBC produced an estrogenic effect by intensifying fluorescence in the transgenic zebrafish, which was counteracted by co-exposure with estrogen receptor antagonist. 4-MBC-upregulated estrogen receptor alpha (erα) mRNA, and an interaction between 4-MBC and ERα suggested ERα's involvement in the 4-MBC-induced estrogenic activity. RNA sequencing unearthed 4-MBC-triggered responses in estrogen stimulus and lipid metabolism. Additionally, 4-MBC-induced hypoactivity and behavioral phenotypes were dependent on the estrogen receptor (ER) pathway. This may have been associated with the disruption of acetylcholinesterase and acetylcholine activities. As a result, 4-MBC increased vitellogenin expression and caused lipid accumulation in the liver of zebrafish larvae. Collectively, this is the first study to report 4-MBC-caused estrogenic effects through the brain-liver-gonad axis. It provides novel insight into how 4-MBC perturbs the brain and liver development.
Topics: Animals; Estrogens; Zebrafish; Estrogen Receptor alpha; Acetylcholinesterase; Sunscreening Agents; Gonads; Receptors, Estrogen; Camphor; Liver; Brain
PubMed: 37506809
DOI: 10.1016/j.envpol.2023.122260 -
Current Opinion in Insect Science Oct 2023Honeybees are highly organized eusocial insects displaying a distinct division of labor. Juvenile hormone (JH) has long been hypothesized to be the major driver of... (Review)
Review
Honeybees are highly organized eusocial insects displaying a distinct division of labor. Juvenile hormone (JH) has long been hypothesized to be the major driver of behavioral transitions. However, more and more experiments in recent years have suggested that the role of this hormone is not as fundamental as hypothesized. Vitellogenin, a common egg yolk precursor protein, seems to be the major regulator of division of labor in honeybees, in connection with nutrition and the neurohormone and transmitter octopamine. Here, we review the role of vitellogenin in controlling honeybee division of labor and its modulation by JH, nutrition, and the catecholamine octopamine.
PubMed: 37391163
DOI: 10.1016/j.cois.2023.101080 -
Biology of Reproduction Apr 2024In oviparous animals, egg yolk is largely derived from vitellogenin, which is taken up from the maternal circulation by the growing oocytes via the vitellogenin...
In oviparous animals, egg yolk is largely derived from vitellogenin, which is taken up from the maternal circulation by the growing oocytes via the vitellogenin receptor. Recently, a novel member of the lipoprotein receptor superfamily termed low-density lipoprotein receptor-related protein 13 was identified and proposed as a candidate of vitellogenin receptor in oviparous animals. However, the roles of low-density lipoprotein receptor-related protein 13 in vitellogenesis are still poorly defined. Here, we investigated the expression, vitellogenin-binding properties, and function of low-density lipoprotein receptor-related protein 13 in zebrafish. Two different lrp13 genes termed lrp13a and lrp13b were found in zebrafish. Reverse transcription polymerase chain reaction and quantitative polymerase chain reaction revealed both lrp13s to be predominantly expressed in zebrafish ovary, and in situ hybridization detected both lrp13s transcripts in the ooplasm of early stage oocytes. Two yeast hybrid studies showed that among eight vitellogenins of zebrafish, Vtg1, 2, and 3 bind to Lrp13a, while Vtg1, 2, and 5 bind to Lrp13b. We created zebrafish lrp13a and lrp13b mutant lines using CRISPR/Cas9. Knockout of lrp13a leads to a male-biased sex ratio and decreased diameter of embryo yolk, while knockout of lrp13b and double knockout of lrp13a and lrp13b leads to the delay of vitellogenesis, followed by follicular atresia. These phenotypes of mutants can be explained by the disruption of vitellogenesis in the absence of Lrp13s. Taken together, our results indicate that both Lrp13a and Lrp13b can serve as vitellogenin receptors in zebrafish among other vitellogenin receptors that are not yet described.
PubMed: 38660750
DOI: 10.1093/biolre/ioae040 -
Reproductive Toxicology (Elmsford, N.Y.) Aug 2023Di-(2-ethylhexyl) terephthalate (DEHTP) is frequently used in food packaging and medical devices as an alternative to di-(2-ethylhexyl) phthalate (DEHP). In this study,...
Di-(2-ethylhexyl) terephthalate (DEHTP) is frequently used in food packaging and medical devices as an alternative to di-(2-ethylhexyl) phthalate (DEHP). In this study, zebrafish pairs were exposed to DEHTP for 21 d and the effects on fertility, sex hormone levels, vitellogenin levels, and transcription of genes along the hypothalamic-pituitary-gonad axis were evaluated. Results showed that mean egg numbers were significantly reduced in the 30 and 300 μg/L DEHTP groups. The adverse effects of DEHTP on hormones and gene transcripts were more prominent in males than in females. In male fish, the gonadosomatic index, hepatosomatic index, and vitellogenin concentration were significantly increased. The results of a significant decrease in testosterone (T) and an increase in the 17β-estradiol (E2)/T ratio in males exposed to 3-300 μg/L DEHTP suggest that the endocrine potential of DEHTP is similar that of DEHP. In females, genes related to gonadotropin-releasing hormone and gonadotropin were up-regulated while E2 was significantly down-regulated. These findings suggest that positive E2 feedback mechanisms in the hypothalamus and pituitary gland are activated to balance sex hormones. The effects of chronic exposure to DEHTP on the neuroendocrine system require further investigation.
Topics: Female; Animals; Male; Zebrafish; Diethylhexyl Phthalate; Vitellogenins; Gonadal Steroid Hormones; Gonads; Water Pollutants, Chemical
PubMed: 37211339
DOI: 10.1016/j.reprotox.2023.108408 -
General and Comparative Endocrinology May 2024Functions of vitellogenins have been in the limelight of fish reproductive physiology research for decades. The Vtg system of acanthomorph teleosts consists of two... (Review)
Review
Functions of vitellogenins have been in the limelight of fish reproductive physiology research for decades. The Vtg system of acanthomorph teleosts consists of two complete forms of Vtgs (VtgAa and VtgAb) and an incomplete form, VtgC. Insufficient uptake and processing of Vtgs and their yolk proteins lead to inadequate oocyte hydration ensuing failure in acquisition of egg buoyancy and early developmental deficiencies. This review presents a summary of our studies on utilization of multiple Vtgs in species with different egg buoyancy characteristics, as examples. Studies of moronids revealed limited degradation of all three forms of lipovitellin heavy chain derived from their three respective forms of Vtg, by which they contribute to the free amino acid pool driving oocyte hydration during oocyte maturation. In later studies, CRISPR/Cas9 was employed to invalidate zebrafish type I, type II and type III Vtgs, which are orthologs of acanthamorph VtgAa, VtgAb and VtgC, respectively. Results revealed type I Vtg to have essential developmental and nutritional functions in both late embryos and larvae. Genomic disturbance of type II Vtg led to high mortalities during the first 24 h of embryonic development. Despite being a minor form of Vtg in zebrafish and most other species, type III Vtg was also found to contribute essentially to the developmental potential of zebrafish zygotes and early embryos. Apart from severe effects on progeny survival, these studies also disclosed previously unreported regulatory effects of Vtgs on fecundity and fertility, and on embryo hatching. We recently utilized parallel reactions monitoring based liquid chromatography tandem mass spectrometry to assess the processing and utilization of lipovitellins derived from different forms of Vtg in Atlantic halibut and European plaice. Results showed the Lv heavy chain of VtgAa (LvHAa) to be consumed during oocyte maturation and the Lv light chain of VtgAb (LvLAb) to be utilized specifically during late larval stages, while all remaining YPs (LvLAa, LvHAb, LvHC, and LvLC) were utilized during or after hatching up until first feeding in halibut. In plaice, all YPs except LvHAa, which similarly to halibut supports oocyte maturation, are utilized from late embryo to late larval development up until first feeding. The collective findings from these studies affirm substantial disparity in modes of utilization of different types of Vtgs among fish species with various egg buoyancy characteristics, and they reveal previously unknown regulatory functions of Vtgs in maintenance of reproductive assets such as maternal fecundity and fertility, and in embryonic hatching. Despite the progress that has been made over the past two decades by examining multiple Vtgs and their functions, a higher complexity of these systems with much greater diversity between species in modes of Vtg utilization is now evident. Further research is needed to reveal novel ways each species has evolved to utilize these complex multiple Vtg systems and to discover unifying principles for this evolution in fishes of diverse lineages, habitats and life history characteristics.
Topics: Animals; Vitellogenins; Zebrafish; Fishes; Oocytes; Oogenesis; Perciformes
PubMed: 38431208
DOI: 10.1016/j.ygcen.2024.114479 -
Insects Nov 2023Searching for artificial diets positively affecting the survival, immune and antioxidant systems of honey bees is one of main challenges occurring in beekeeping. Among...
Effects of Virgin Coconut Oil-Enriched Diet on Immune and Antioxidant Enzymatic Activity, Fat and Vitellogenin Contents in Newly Emerged and Forager Bees ( L.) Reared in Cages.
Searching for artificial diets positively affecting the survival, immune and antioxidant systems of honey bees is one of main challenges occurring in beekeeping. Among nutrients, lipids play a significant role in insect nutrition as structural components in cell membranes, energy sources and reserves, and are involved in many physiological processes. In this context, the aim of this work was to investigate the effect of 0.5% and 1% coconut oil-enriched diet administration on newly emerged and forager bees survival rate, feed intake, immune system, antioxidant system and both fat and vitellogenin content. In newly emerged bees, supplementation with 1% coconut oil determined a decrease in feed consumption, an increase in survival rate from the 3rd to 14th day of feeding, a short-term decrease in phenoloxidase activity, an increase in body fat and no differences in vitellogenin content. Conversely, supplementation with 0.5% coconut oil determined an increase in survival rate from the 3rd to 15th day of feeding and an increase in fat content in the long term (i.e., 20 days). Regarding the forager bee diet, enrichment with 0.5% and 1% coconut oil only determined an increase in fat content. Therefore, supplementation with coconut oil in honey bee diets at low percentages (0.5 and 1%) determines fat gain. Further investigations to evaluate the use of such supplement foods to prevent the fat loss of weak families during winter are desirable.
PubMed: 37999055
DOI: 10.3390/insects14110856 -
Frontiers in Physiology 2023
PubMed: 37469557
DOI: 10.3389/fphys.2023.1244594