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Vanderplanck M, Zerck P, Lognay G, Michez D. Generalized host-plant feeding can hide sterol-specialized foraging behaviors in bee-plant interactions. Ecol Evol 2020; 10:150-162. [PMID: 31993117 PMCID: PMC6972837 DOI: 10.1002/ece3.5868] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/24/2019] [Accepted: 11/03/2019] [Indexed: 11/17/2022] Open
Abstract
Host-plant selection is a key factor driving the ecology and evolution of insects. While the majority of phytophagous insects is highly host specific, generalist behavior is quite widespread among bees and presumably involves physiological adaptations that remain largely unexplored. However, floral visitation patterns suggest that generalist bees do not forage randomly on all available resources. While resource availability and accessibility as well as nectar composition have been widely explored, pollen chemistry could also have an impact on the range of suitable host-plants. This study focuses on particular pollen nutrients that cannot be synthesized de novo by insects but are key compounds of cell membranes and the precursor for molting process: the sterols. We compared the sterol composition of pollen from the main host-plants of three generalist bees: Anthophora plumipes, Colletes cunicularius, and Osmia cornuta, as well as one specialist bee Andrena vaga. We also analyzed the sterols of their brood cell provisions, the tissues of larvae and nonemerged females to determine which sterols are used by the different species. Our results show that sterols are not used accordingly to foraging strategy: Both the specialist species A. vaga and the generalist species C. cunicularius might metabolize a rare C27 sterol, while the two generalist species A. plumipes and O. cornuta might rather use a very common C28 sterol. Our results suggest that shared sterolic compounds among plant species could facilitate the exploitation of multiple host-plants by A. plumipes and O. cornuta whereas the generalist C. cunicularius might be more constrained due to its physiological requirements of a more uncommon dietary sterol. Our findings suggest that a bee displaying a generalist foraging behavior may sometimes hide a sterol-specialized species. This evidence challenges the hypothesis that all generalist free-living bee species are all able to develop on a wide range of different pollen types.
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Affiliation(s)
- Maryse Vanderplanck
- Laboratory of ZoologyResearch Institute for BiosciencesUniversity of MonsMonsBelgium
- Evo‐Eco‐Paleo ‐ UMR 8198CNRSUniversity of LilleLilleFrance
| | - Pierre‐Laurent Zerck
- Laboratory of ZoologyResearch Institute for BiosciencesUniversity of MonsMonsBelgium
| | - Georges Lognay
- Laboratory of Analytical ChemistryGembloux Agro‐Bio TechUniversity of LiègeGemblouxBelgium
| | - Denis Michez
- Laboratory of ZoologyResearch Institute for BiosciencesUniversity of MonsMonsBelgium
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Lavrynenko O, Rodenfels J, Carvalho M, Dye NA, Lafont R, Eaton S, Shevchenko A. The ecdysteroidome of Drosophila: influence of diet and development. Development 2015; 142:3758-68. [PMID: 26395481 DOI: 10.1242/dev.124982] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 09/03/2015] [Indexed: 01/06/2023]
Abstract
Ecdysteroids are the hormones regulating development, physiology and fertility in arthropods, which synthesize them exclusively from dietary sterols. But how dietary sterol diversity influences the ecdysteroid profile, how animals ensure the production of desired hormones and whether there are functional differences between different ecdysteroids produced in vivo remains unknown. This is because currently there is no analytical technology for unbiased, comprehensive and quantitative assessment of the full complement of endogenous ecdysteroids. We developed a new LC-MS/MS method to screen the entire chemical space of ecdysteroid-related structures and to quantify known and newly discovered hormones and their catabolites. We quantified the ecdysteroidome in Drosophila melanogaster and investigated how the ecdysteroid profile varies with diet and development. We show that Drosophila can produce four different classes of ecdysteroids, which are obligatorily derived from four types of dietary sterol precursors. Drosophila makes makisterone A from plant sterols and epi-makisterone A from ergosterol, the major yeast sterol. However, they prefer to selectively utilize scarce ergosterol precursors to make a novel hormone 24,28-dehydromakisterone A and trace cholesterol to synthesize 20-hydroxyecdysone. Interestingly, epi-makisterone A supports only larval development, whereas all other ecdysteroids allow full adult development. We suggest that evolutionary pressure against producing epi-C-24 ecdysteroids might explain selective utilization of ergosterol precursors and the puzzling preference for cholesterol.
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Affiliation(s)
- Oksana Lavrynenko
- Max Planck Institute for Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany
| | - Jonathan Rodenfels
- Max Planck Institute for Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany
| | - Maria Carvalho
- Max Planck Institute for Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany
| | - Natalie A Dye
- Max Planck Institute for Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany
| | - Rene Lafont
- Sorbonne Universités, University Pierre and Marie Curie, Paris 06, IBPS-BIOSIPE, 7 Quai Saint Bernard, Case Courrier 29, Paris Cedex 05 75252, France
| | - Suzanne Eaton
- Max Planck Institute for Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany
| | - Andrej Shevchenko
- Max Planck Institute for Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany
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Blais C, Blasco T, Maria A, Dauphin-Villemant C, Lafont R. Characterization of ecdysteroids in Drosophila melanogaster by enzyme immunoassay and nano-liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:925-32. [PMID: 20303327 DOI: 10.1016/j.jchromb.2010.02.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 02/08/2010] [Accepted: 02/14/2010] [Indexed: 11/24/2022]
Abstract
Ecdysteroids are polyhydroxylated steroids that function as molting hormones in insects. 20-Hydroxyecdysone (a 27C-ecdysteroid) is classically considered as the major steroid hormone of Drosophilamelanogaster, but this insect also contains 28C-ecdysteroids. This arises from both the use of several dietary sterols as precursors for the synthesis of its steroid hormones, and its inability to dealkylate the 28C-phytosterols to produce cholesterol. The nature of Drosophila ecdysteroids has been re-investigated using both high-performance liquid chromatography coupled to enzyme immunoassay and a particularly sensitive nano-liquid chromatography-mass spectrometry methodology, while taking advantage of recently available ecdysteroid standards isolated from plants. In vitro incubations of the larval steroidogenic organ, the ring-gland, reveals the synthesis of ecdysone, 20-deoxy-makisterone A and a third less polar compound identified as the 24-epimer of the latter, while wandering larvae contain the three corresponding 20-hydroxylated ecdysteroids. This pattern results from the simultaneous use of higher plant sterols (from maize) and fungal sterols (from yeast). The physiological relevance of all these ecdysteroids, which display different affinities to the ecdysteroid receptors, is still a matter of debate.
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Affiliation(s)
- Catherine Blais
- UPMC Univ Paris 06, UMR CNRS 7622, Equipe Biogenèse des signaux hormonaux, Case 29, 7 Quai Saint Bernard, F-75005 Paris, France.
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4
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Warren JT, Yerushalmi Y, Shimell MJ, O'Connor MB, Restifo L, Gilbert LI. Discrete pulses of molting hormone, 20-hydroxyecdysone, during late larval development of Drosophila melanogaster: correlations with changes in gene activity. Dev Dyn 2006; 235:315-26. [PMID: 16273522 PMCID: PMC2613944 DOI: 10.1002/dvdy.20626] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Periodic pulses of the insect steroid molting hormone 20-hydroxyecdysone (20E), acting via its nuclear receptor complex (EcR/USP), control gene expression at many stages throughout Drosophila development. However, during the last larval instar of some lepidopteran insects, subtle changes in titers of ecdysteroids have been documented, including the so-called "commitment peak." This small elevation of 20E reprograms the larva for metamorphosis to the pupa. Similar periods of ecdysteroid immunoreactivity have been observed during the last larval instar of Drosophila. However, due to low amplitude and short duration, along with small body size and staging difficulties, their timing and ecdysteroid composition have remained uncertain. Employing a rigorous regimen of Drosophila culture and a salivary gland reporter gene, Sgs3-GFP, we used RP-HPLC and differential ecdysteroid RIA analysis to determine whole body titers of 20E during the last larval instar. Three small peaks of 20E were observed at 8, 20, and 28 hr following ecdysis, prior to the well-characterized large peak around the time of pupariation. The possible regulation of 20E levels by biosynthetic P450 enzymes and the roles of these early peaks in coordinating gene expression and late larval development are discussed.
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Affiliation(s)
- James T. Warren
- Department of Biology, University of North Carolina, CB#3280, Chapel Hill, NC 27599-3280, USA
| | - Yoram Yerushalmi
- ARL Division of Neurobiology, University of Arizona, Tucson, AZ 85721-0077
| | - Mary Jane Shimell
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael B. O'Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Linda Restifo
- ARL Division of Neurobiology, University of Arizona, Tucson, AZ 85721-0077
| | - Lawrence I. Gilbert
- Department of Biology, University of North Carolina, CB#3280, Chapel Hill, NC 27599-3280, USA
- Corresponding author. Tel.: +1-919-966-2055; fax: +1-919-962-1344. E-mail address: (L.I. Gilbert)
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Warren JT, Wismar J, Subrahmanyam B, Gilbert LI. Woc (without children) gene control of ecdysone biosynthesis in Drosophila melanogaster. Mol Cell Endocrinol 2001; 181:1-14. [PMID: 11476936 DOI: 10.1016/s0303-7207(01)00404-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The first step in ecdysteroidogenesis, i.e. the 7,8-dehydrogenation of dietary cholesterol (C) to 7-dehydrocholesterol (7dC), is blocked in Drosophila melanogaster homozygous woc (without children) third instar larval ring glands (source of ecdysone). Unlike ring glands from wild-type D. melanogaster larvae, glands from woc mutants cannot convert radiolabelled C or 25-hydroxycholesterol (25C) to 7dC or 7-dehydro-25-hydroxycholesterol (7d25C) in vitro, nor to ecdysone (E). Yet, when these same glands are incubated with synthetic tracer 7d25C, the rate of metabolism of this polar Delta(5,7)-sterol into E is identical to that observed with glands from comparably staged wild-type larvae. The absence of this enzymatic activity in vivo is probably the direct cause of the observed low whole-body ecdysteroid titers in late third instar homozygous mutant larvae, the low ecdysteroid secretory activity in vitro of brain-ring gland complexes from these animals, and the failure of the larvae to pupariate (undergo metamorphosis). Oral administration of 7dC, but not C, results in a dramatic increase in ecdysteroid production both in vivo and in vitro by the woc mutant brain-ring gland complexes and affects a partial rescue to the beginning of pupal-adult development, but no further, despite elevated whole-body ecdysteroid titers. Data previously reported (Wismar et al., 2000) indicate that the woc gene encodes a zinc-finger protein that apparently modulates the activity of the 7,8-dehydrogenase.
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Affiliation(s)
- J T Warren
- Department of Biology, Campus Box #3280, University of North Carolina at Chapel Hill, 27599-3280, USA
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Baker KD, Warren JT, Thummel CS, Gilbert LI, Mangelsdorf DJ. Transcriptional activation of the Drosophila ecdysone receptor by insect and plant ecdysteroids. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2000; 30:1037-1043. [PMID: 10989290 DOI: 10.1016/s0965-1748(00)00075-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A number of insect ecdysteroids, plant ecdysteroids and juvenoids were assayed for their ability to activate Drosophila nuclear receptors in transfected tissue culture cells. Discrete modifications to 20-hydroxyecdysone, the apparent natural ligand for the ecdysone receptor (EcR), conferred dramatic changes on the transcriptional activity of this receptor, suggesting that other biologically relevant EcR ligands may exist. Conversely, none of the compounds tested had a significant effect on the activity of three Drosophila orphan nuclear receptors: DHR38, DHR78 or DHR96. Taken together, these results demonstrate the selectivity of EcR for a series of natural and synthetic ecdysone agonists and suggest that as yet untested compounds may be responsible for activating DHR38, DHR78 and DHR96.
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Affiliation(s)
- K D Baker
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 75390-9050, Dallas, TX, USA
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Warren JT, Dai JD, Gilbert LI. Can the insect nervous system synthesize ecdysteroids? INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1999; 29:571-579. [PMID: 10406093 DOI: 10.1016/s0965-1748(99)00033-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The term "neurosteroid" refers to both classic and unique steroid molecules that are synthesized from cholesterol (C) by the central and peripheral nervous systems of higher vertebrates. Therein, they accumulate and modulate nervous activity by a variety of mechanisms other than the classic steroid receptor-mediated modulation of genomic activity, although such may also be involved. Since the insect nervous system expresses ecdysteroid receptors and responds both directly and developmentally to ecdysteroids, the possibility of ecdysteroidogenesis in the pupal and adult central and peripheral nervous system of Manduca sexta and the nervous system of Drosophila melanogaster larvae was investigated. The endogenous concentrations of the critical, dietary-derived delta 5,7-sterols ergosterol and 7-dehydrocholesterol (7dC) remained 10 to 20-fold higher in the Manduca pupal and adult nervous tissues than was found in the larval hemolymph at the cessation of feeding. In addition, it was determined that the Manduca pupal nervous system, but not that of the adult, could synthesize 3H/14C-7dC or 3H-7-dehydro-25-hydroxycholesterol (3H-7d25C) from 3H/14C-cholesterol (3H/14C-C) or the polar sterol substrate 3H-25-hydroxycholesterol (3H-25C), respectively. However, none of the nervous system samples from the two species and the several stages analyzed, a small window of neural development in these insects, were capable of incorporating any of the above tracer precursor sterols into a radiolabelled ecdysteroid, i.e. less than 0.0005%. Thus, the absence of neurosteroidogenesis by the insect nervous system stands in sharp contrast to previously described nervous system steroid hormone biosynthesis by the mammalian nervous system.
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Affiliation(s)
- J T Warren
- Department of Biology, University of North Carolina at Chapel Hill 27599-3280, USA
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8
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Warren JT, Bachmann JS, Dai JD, Gilbert LI. Differential incorporation of cholesterol and cholesterol derivatives into ecdysteroids by the larval ring glands and adult ovaries of Drosophila melanogaster: a putative explanation for the l(3)ecd1 mutation. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1996; 26:931-943. [PMID: 9014338 DOI: 10.1016/s0965-1748(96)00059-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Studies in vitro revealed that intact ring glands of Drosophila melanogaster convert tritiated cholesterol (C) and 25-hydroxycholesterol (25C) via 7-dehydrocholesterol (7dC) and 7-dehydro-25-hydroxycholesterol (7d25C), respectively, to ecdysone (E) and 2-deoxyecdysone (2dE), while both intact and homogenized ovaries synthesize only 2dE from these precursors. Emulsified 7d25C was incorporated directly into ecdysteroids by these tissue preparations at a much greater rate than was 7d25C made in situ from 25C. To probe the basis of the biochemical defect in the ecdysteroid deficient conditional mutant ecdysoneless (ecd1), the differential incorporation into ecdysteroids of C (via 7dC), and particularly of 25C (via 7d25C), was measured relative to that observed after the incubation of 7d25C directly with both wild type and mutant tissues in vitro at 30 degrees C, the restrictive temperature. Both C and 25C were equally 7,8-dehydrogenated in situ to 7dC or 7d25C, respectively, by both wild type and mutant tissues at 30 degrees C. However, the rate of subsequent conversion of either of these delta 5,7-sterol intermediates synthesized in situ to ecdysteroids was reduced an average of 50% in the mutant tissues relative to the wild type. Yet, when emulsified 7d25C was incubated directly with either the wild type or mutant tissues at the restrictive temperature, the amplified rate of conversion of the freely available 7d25C to ecdysteroid by these tissues was identical. These data suggest that the defect in ecd1 tissue-mediated ecdysteroidogenesis does not involve a "hit" on any of the enzymes involved in either the 7,8-dehydrogenation of C or 25C or in the subsequent oxidation of 7d25C or 7dC to ecdysteroid. Rather, the mutation appears to affect the expression of a gene governing the translocation of delta 5,7-sterol intermediates from the subcellular compartment where they are synthesized and/or stored to the site of subsequent oxidation to ecdysteroid.
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Affiliation(s)
- J T Warren
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280, USA
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Feldlaufer MF, Weirich GF, Imberski RB, Svoboda JA. Ecdysteroid production in Drosophila melanogaster reared on defined diets. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1995; 25:709-712. [PMID: 7627202 DOI: 10.1016/0965-1748(95)00009-k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Larvae of Drosophila melanogaster were reared aseptically on defined diets containing either cholesterol, campesterol or sitosterol as the only dietary sterol. Sterol analyses of pupae revealed that insects reared on campesterol and sitosterol diets contained 3.3 and 8.1% cholesterol, indicative of an ability to accumulate this sterol. Ecdysone and 20-hydroxyecdysone were the predominant ecdysteroids in insects from all diet studies, though makisterone A was detected in pupae reared on campesterol and sitosterol.
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Affiliation(s)
- M F Feldlaufer
- Insect Neurobiology & Hormone Laboratory, USDA, Beltsville, MD 20705, USA
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Budd E, Käuser G, Koolman J. On the control of ecdysone biosynthesis by the central nervous system of blowfly larvae. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 1993; 23:181-197. [PMID: 8358072 DOI: 10.1002/arch.940230405] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ecdysone was found to be the major secreted steroid of ring glands dissected from blowfly larvae and incubated in vitro. Other secretory products such as 3-dehydroecdysone and 20-deoxy-makisterone A could not be detected when the glands were labelled with tritiated cholesterol. Ecdysone synthesis and secretion were found to be tightly coupled. The highest rate of secretion was observed a few hours before pupariation. In vitro, the rate of ecdysone secretion by ring glands was affected significantly by coincubation with the central nervous system (CNS). Modulating effects from the CNS to the gland were mediated both by culture medium and by nerve connections. Distinct parts of the CNS revealed multiple and partially opposite effects on ecdysone secretion, suggesting a more complex control than had been anticipated. Multiple neural control systems appear to be involved. Moreover, the observed effects changed with development during the second half of the third instar, reflecting a significant plasticity of neural control.
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Affiliation(s)
- E Budd
- Physiologisch Chemisches Institut, Universität Marburg, Germany
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Feldlaufer M, Svoboda J. Sterol utilization and ecdysteroid content in the house fly, Musca domestica (L.). ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0020-1790(91)90063-k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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WARREN JT, HETRU C. Ecdysone biosynthesis: Pathways, enzymes, and the early steps problem. INVERTEBR REPROD DEV 1990. [DOI: 10.1080/07924259.1990.9672131] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Rachinsky A, Strambi C, Strambi A, Hartfelder K. Caste and metamorphosis: hemolymph titers of juvenile hormone and ecdysteroids in last instar honeybee larvae. Gen Comp Endocrinol 1990; 79:31-8. [PMID: 2354779 DOI: 10.1016/0016-6480(90)90085-z] [Citation(s) in RCA: 152] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Juvenile hormone (JH) and ecdysteroid titers are critical factors for caste development and metamorphosis in the last larval instar of the honeybee, Apis mellifera. Two highly sensitive radioimmunoassays were used for the determination of these hormones in the hemolymph. For juvenile hormone, which is of prime importance for the control of caste development in honeybees, our data show a caste-specific peak in queen larvae of the early fifth instar. A second peak appears in prepupae of both castes which probably is responsible for the regulation of the pupal moult. A single peak of ecdysteroids was observed in prepupae of both castes. In queens, however, the titer increases distinctly earlier than in worker larvae. The ecdysteroid composition of this prepupal peak was determined by high-performance liquid chromatography separation followed by radioimmunoassay. Makisterone A proved to be the main ecdysteroid compound, but 20-hydroxyecdysone was also found in significant amounts.
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Affiliation(s)
- A Rachinsky
- LS Entwicklungsphysiologie, Zoologisches Institut, Tübingen, Federal Republic of Germany
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14
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15
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Sommé-Martin G, Colardeau J, Lafont R. Conversion of ecdysone and 20-hydroxyecdysone into 3-dehydroecdysteroids is a major pathway in third instar Drosophila melanogaster larvae. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0020-1790(88)90082-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Henrich VC, Pak MD, Gilbert LI. Neural factors that stimulate ecdysteroid synthesis by the larval ring gland of Drosophila melanogaster. J Comp Physiol B 1987; 157:543-9. [PMID: 3121682 DOI: 10.1007/bf00700973] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The larval ring gland of Drosophila melanogaster is the source of ecdysteroids responsible for larval-larval and larval-pupal molting. An extract prepared from the Drosophila larval central nervous system, that presumably contains prothoracicotropic hormone, elicits a significant and dose-dependent in vitro increase in ecdysteroid synthesis by ring glands from wandering third instar larvae. The synthesis of all three ecdysteroids previously identified as ring gland products is elevated by more than two-fold in the presence of neural extract. The maximum response occurs within 30 min and can be sustained for at least two hours after a 30 min exposure to neural extract. No non-neural tissue extracts evoke a response and most of the prothoracicotropic activity originates in the ventral ganglion. However, while extract prepared from larval brains elicits only a slight increase in ecdysteroid synthesis, it enhances the activity of a submaximal dose of ventral ganglion extract. This suggests that two or more neural factors, at least one from the brain lobes and another from the ventral ganglion, interact to stimulate ecdysteroid synthesis by the larval ring gland.
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Affiliation(s)
- V C Henrich
- Department of Biology, University of North Carolina, Chapel Hill 27514
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