Search results for "vitellogenin"

Effect of starvation on haemolymph vitellogenins and ovary uptake in Spilostethus pandurus

1993

Abstract 1. 1. Starvation reduces haemolymph vitellogenins and their incorporation by developing oocytes in S. pandurus adult females. 2. 2. Access to food restores unspecifically the protein levels in both haemolymph and ovaries. 3. 3. Topical treatments with JH promote de novo specific synthesis of vitellogenins and incorporation by the ovaries. 4. 4. These results point to a strong role of the JH as the regulatory factor of both reproductive phenomena in S. pandurus .

Effect of temperature on the duration of sensitive period and on the number of photoperiodic cycles required for the induction of reproductive diapau…

2013

Abstract Correct timing of the induction of photoperiodic reproductive diapause has been found to play an important role in the life cycle of several northern insect species. However, even when the environmental conditions are favourable for diapause, the switch to diapause can only take place when the females are in a proper developmental and physiological stage, referred to as the sensitive period (SP) for diapause. We have previously shown that in a northern fly species, Drosophila montana, the developmental pathway of the ovaries (direct maturation vs. diapause) is determined by photoperiodic cues that the females receive after eclosion. Here, we have studied the effects of temperature …

Analysis of involvement of the 3?-untranslated regions in regulating mRNA stability for vitellogenin, cyanoprotein ?, and cyanoprotein ? from the bea…

2002

The degradation of the 3'-untranslated regions (UTRs) of vitellogenin, cyanoprotein alpha, and cyanoprotein beta from the bean bug, Riptortus clavatus, was analyzed in vitro. The degradation pattern was similar for all three RNAs, with a high degradation rate in non-diapausing adult insects and no degradation in the fifth instar nymphs and in diapausing adults, and was not correlated with the expression levels of these three proteins. Proteins binding to the 3'-UTRs were detected in polysomal and cytosolic extracts. These factors, however, were present in all developmental stages. The abundance of the polysomal factor showed little variation, but the cytosolic factor was enriched in adult i…

Advancing the ecotoxicological relevancy of zebrafish : application of early-juvenile 20dpfZF to assess xenoestrogenicity of environmental chemicals …

2014

Use of Early Juvenile Zebrafish Danio Rerio for In-Vivo Assessment of Endocrine Modulation by Xenoestrogens

2013

Reliable and cost-effective early-life stage (ELS) bioassays incorporating practical experimentation without compromising scientific relevance are crucial in chemical risk assessment. This study investigated the use of 20 days- post-fertilization life stage ( 20dpfZF ) of zebrafish Danio rerio to screen environmental chemicals known to be estrogenic in adult fish. Firstly, studies with key genes in steroidogenesis were conducted; the brain isoform of aromatase gene ( cyp19a1b ) being the most prominently expressed biomarker. Regulation of mRNA levels of molecular biomarkers, vitellogenin 1 gene ( vtg1) and cyp19a1b were selected to assess the endocrine modulation by xenoestrogens, 17α-ethin…

Properties of sea urchin coelomocyte agglutinins

1996

We examined some biological activities of a 200-kDa glycoprotein, referred to as Paracentrotus lividus vitellogenin, contained both in the coelomic fluid and in a subpopulation of coelomocytes called «colourless spherula cells». Cell-free coelomic fluid, coelomocyte lysate and supernatant obtained after coelomocyte washings were assayed for hemagglutinating activity. All samples agglutinated rabbit erythrocytes in a calcium-dependent way. The comparison between the electrophoretic patterns of erythrocyte lysates, before and after incubation with the coelomic fluid, revealed that a 200-kDa band was obtained from membranes of agglutinated erythrocytes. In addition, polyclonal antibodies again…

Characterization of vitellogenins in Spilostethus pandurus (Hemiptera): Immunoelectrophoretic studies and short-term labelling experiments

1992

Abstract The haemolymph of Spilostethus pandurus contains three female-specific proteins (I, II and III) as revealed by SDS-PAGE. Antibodies prepared against them recognize three fractions (4, 5 and 6) in ovarian extracts which have similar molecular weights suggesting that I, II and III are vitellogenins. Upon injection of a 14C amino acid mixture into vitellogenic females, labelled proteins first appear in the fat body, then in the haemolymph and next in the ovarian follicles.

Biomarker responses by crucian carp () living in a pond of secondary treated pulp mill effluent

1999

Biochemical and histological biomarkers by the adult crucian carp ( Carassius carassius (L.)) living in a biologically treated pulp mill effluent were studied. Enocell pulp mill in Uimaharju, Finland, discharges its effluents through a waste water pond to the River Pielisjoki. This pond harbours an introduced crucian carp population that apparently reproduces on site. The objective of the present study was to measure possible hormonal effects of treated pulp mill effluent on crucian carps living in a wastewater pond. Adult fish were collected for analysis by traps. A reference population was sampled from a small natural pond. Blood and bile samples were taken for analyses of hemoglobin, hem…

Transfer of Immunity from Mother to Offspring Is Mediated via Egg-Yolk Protein Vitellogenin.

2015

Insect immune systems can recognize specific pathogens and prime offspring immunity. High specificity of immune priming can be achieved when insect females transfer immune elicitors into developing oocytes. The molecular mechanism behind this transfer has been a mystery. Here, we establish that the egg-yolk protein vitellogenin is the carrier of immune elicitors. Using the honey bee, Apis mellifera, model system, we demonstrate with microscopy and western blotting that vitellogenin binds to bacteria, both Paenibacillus larvae – the gram-positive bacterium causing American foulbrood disease – and to Escherichia coli that represents gram-negative bacteria. Next, we verify that vitellogenin bi…

Vitellogenesis inhibition in Oncopeltus fasciatus females (Heteroptera: Lygaeidae) exposed to cadmium

2005

Abstract Newly moulted females of the insect Oncopeltus fasciatus were exposed to cadmium (Cd) dissolved in the drinking water (50–400 mg l −1 Cd) for 5 days. Cd exposure delayed ovarian maturation and inhibited egg production. Exposure to Cd, moreover, decreased hemolymph levels of the two major vitellogenin polypeptides of O. fasciatus , VG1 and VG2, in a concentration-dependent way, probably by a reduction in their synthesis. The ovarian levels of VG1 and VG2 were also decreased in Cd-exposed females. It was next investigated whether Cd effects might be a consequence of the endocrine disruption of vitellogenin synthesis, which is controlled by juvenile hormone (JH). JH replacement therap…