Search results for "Vitellogenins"
showing 10 items of 19 documents
Comparative transcriptomic analysis of the mechanisms underpinning ageing and fecundity in social insects.
2021
The exceptional longevity of social insect queens despite their lifelong high fecundity remains poorly understood in ageing biology. To gain insights into the mechanisms that might underlie ageing in social insects, we compared gene expression patterns between young and old castes (both queens and workers) across different lineages of social insects (two termite, two bee and two ant species). After global analyses, we paid particular attention to genes of the insulin/insulin-like growth factor 1 signalling (IIS)/target of rapamycin (TOR)/juvenile hormone (JH) network, which is well known to regulate lifespan and the trade-off between reproduction and somatic maintenance in solitary insects…
Vitellogenin-like A–associated shifts in social cue responsiveness regulate behavioral task specialization in an ant
2018
Division of labor and task specialization explain the success of human and insect societies. Social insect colonies are characterized by division of labor, with workers specializing in brood care early and foraging later in life. Theory posits that this task switching requires shifts in responsiveness to task-related cues, yet experimental evidence is weak. Here, we show that a Vitellogenin (Vg) ortholog identified in an RNAseq study on the ant T. longispinosus is involved in this process: using phylogenetic analyses of Vg and Vg-like genes, we firstly show that this candidate gene does not cluster with the intensively studied honey bee Vg but falls into a separate Vg-like A cluster. Second…
Crustacean Hemolymph Lipoproteins
2020
Lipoproteins mediate the transport of apolar lipids in the hydrophilic environment of physiological fluids such as the vertebrate blood and the arthropod hemolymph. In this overview, we will focus on the hemolymph lipoproteins in Crustacea that have received most attention during the last years: the high density lipoprotein/β-glucan binding proteins (HDL-BGBPs), the vitellogenins (VGs), the clotting proteins (CPs) and the more recently discovered large discoidal lipoproteins (dLPs). VGs are female specific lipoproteins which supply both proteins and lipids as storage material for the oocyte for later use by the developing embryo. Unusual within the invertebrates, the crustacean yolk protein…
Not Only for Egg Yolk—Functional and Evolutionary Insights from Expression, Selection, and Structural Analyses of Formica Ant Vitellogenins
2014
Vitellogenin (Vg), a storage protein, has been extensively studied for its egg-yolk precursor role, and it has been suggested to be fundamentally involved in caste differences in social insects. More than one Vg copy has been reported in several oviparous species, including ants. However, the number and function of different Vgs, their phylogenetic relatedness, and their role in reproductive queens and nonreproductive workers have been studied in few species only. We studied caste-biased expression of Vgs in seven Formica ant species. Only one copy of conventional Vg was identified in Formica species, and three Vg homologs, derived from ancient duplications, which represent yet undiscovered…
Detection of vitellogenin in a subpopulation of sea urchin coelomocytes.
1994
Sea urchin vitellogenin is a high molecular weight glycoprotein, which is the precursor of the major yolk protein present in the unfertilized egg. Vitellogenin processing into the major yolk protein and its further enzymatic cleavage during sea urchin embryonic development, has been extensively described, and the adhesive properties of the processed molecule have been studied. The function of vitellogenin in the adult, where it has been found in the coelomic fluid of both male and female individuals, is still unknown, although its role on promoting the adhesion of embryonic cells has been shown. In this report we describe the detection of vitellogenin in lysates of whole circulating coelomo…
Vitellogenin polypeptide levels in one susceptible and one cadmium-resistant strain of Oncopeltus fasciatus (Heteroptera: Lygaeidae), and its role in…
2005
The heavy metal Cd has recently been shown to have endocrine disrupting activity in different vertebrate species. In the insect Oncopeltus fasciatus, Cd exposure delays ovarian maturation and inhibits vitellogenesis, probably through a reduction in vitellogenin (Vg) polypeptide synthesis. An O. fasciatus strain was selected in the laboratory for Cd resistance with gradually increasing Cd concentrations for 50 generations. Cd-selected (OCdR) insects were 2.7-2.3 times more resistant to chronic exposure to Cd than susceptible (OS) insects. OCdR females showed increased (up to 90%) Vg polypeptide levels in hemolymph. Vg polypeptide synthesis was equally decreased in OCdR and OS females after a…
Short-term exposure to sublethal tebuconazole induces physiological impairment in male zebrafish (Danio rerio).
2010
Abstract The aim of the present study was to assess the physiological response of male zebrafish Danio rerio to the fungicide tebuconazole and recovery in fungicide-free water. Acute toxicity tests were carried out and the median lethal concentration (LC 50 ) from 24 to 96 h was calculated. The fish were exposed to a sublethal fungicide concentration of 230 μg/L for 7 or 14 days and allowed to recover for 7 or 14 more days, respectively. Whole-body levels of vitellogenins, triglycerides, cholesterol, glucose, lactate and proteins as well as the activities γ-glutamil transpeptidase (γ-GT), alanin aminotransferase (AlAT), alkaline phosphatase (AP) and lactate dehydrogenase (LDH) were assayed;…
Vitellogenin from female and estradiol-stimulated male river lampreys (Lampetra fluviatilis L.)
2001
The influence of estradiol-17β (E2) on vitellogenesis is well documented for a number of oviparous craniates. We have examined the role that estradiol-17β plays in the induction and regulation of vitellogenin synthesis in the maturing European river lamprey, Lampetra fluviatilis. In both females and males the estradiol-17β concentrations in the plasma reached comparable maximum values in March, only a few weeks before spawning. Throughout the spawning run, the vitellogenin titer in the blood of females remains rather constant while the ovary volume increases. In contrast, we never found circulating VTG in untreated male lampreys. The synthesis and secretion of the yolk precursor molecule ca…
Regulation of vitellogenesis in Nereis virens (Annelida: Polychaeta): effect of estradiol-17beta on eleocytes.
2005
Abstract In the marine polychaete Nereis virens , the yolk protein precursor vitellogenin (Vg) is synthesized in specialized coelomic cells (eleocytes) during oogenesis. This process was visualized by immunohistochemistry using antibodies raised against the yolk protein. Transversal sections from male and female worms confirmed that eleocytes from females but not from males produce Vg. In order to investigate the hormonal regulation of Vg synthesis, eleocytes were incubated in vitro with estradiol-17β (E 2 ) at a concentration of 1 μg/l for up to three days. A strong increase in Vg secretion was detected by ELISA in culture media of treated eleocytes from vitellogenic females. In contrast, …
Expression of the Vitellogenin Gene in the Liver of Juvenile Whitefish (Coregonus lavaretus L. s.l.) Exposed to Effluents from Pulp and Paper Mills
1999
Juvenile whitefish (Coregonus lavaretus L. s.l.) were exposed by caging in the field to diluted effluents from three operating pulp, paper, and paperboard mills in Southern Lake Saimaa, Finland. The expression of the vitellogenin gene, used as a biomarker of estrogenic contamination of effluents, was measured using a Northern blotting method. Increased mRNA levels, the most specific and reliable evidence for estrogen receptor-mediated actions in vivo, were found in fish caged in the vicinity of one of three mills studied. This mill was found to discharge wood-derived compounds, such as sterols and resin acids, into Lake Saimaa in amounts considerably exceeding those from the other two mills…