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Urbán-Duarte D, Tomita S, Sakai H, Sezutsu H, De La Torre-Sánchez JF, Kainoh Y, Furukawa S, Uchino K. An Effective Chemical Permeabilization of Silkworm Embryos. Bioengineering (Basel) 2023; 10:bioengineering10050563. [PMID: 37237633 DOI: 10.3390/bioengineering10050563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/24/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023] Open
Abstract
The lipid layer surrounding the vitelline membrane of insect eggs has a critical role in the waterproofing and desiccation resistance of embryos. However, this lipid layer also prevents the flux of chemicals into the embryos, such as cryoprotectants, which are required for successful cryopreservation. The permeabilization studies of silkworm embryos remain insufficient. Therefore, in this study, we developed a permeabilization method to remove the lipid layer in the silkworm, Bombyx mori, and examined factors affecting the viability of dechorionated embryos, including the types and exposure times of chemicals and embryonic stages. Among the chemicals used, hexane and heptane were effective for permeabilization, whereas Triton X-100 and Tween-80 were less effective. Regarding the embryonic stages, there were significant differences between 160 and 166 h after egg laying (AEL) at 25 °C. Consequently, we found that the treatment of 160 AEL embryos with hexane for 30 s was the best condition for the permeability and viability of embryos, in which over 62% of the permeabilized embryos grew up to the second larval instar and their moths could lay fertilized eggs. Our method can be used for various purposes, including permeability investigations using other chemicals and embryonic cryopreservation.
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Affiliation(s)
- David Urbán-Duarte
- Centro Nacional de Recursos Genéticos, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Tepatitlán de Morelos 47600, Jalisco, Mexico
| | - Shuichiro Tomita
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba 305-8634, Ibaraki, Japan
| | - Hiroki Sakai
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba 305-8634, Ibaraki, Japan
| | - Hideki Sezutsu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba 305-8634, Ibaraki, Japan
| | - José Fernando De La Torre-Sánchez
- Centro Nacional de Investigación Disciplinaria en Agricultura Familiar, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Ojuelos 47540, Jalisco, Mexico
| | - Yooichi Kainoh
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8572, Ibaraki, Japan
| | - Seiichi Furukawa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8572, Ibaraki, Japan
| | - Keiro Uchino
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba 305-8634, Ibaraki, Japan
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Bowen J, Schloop AE, Reeves GT, Menegatti S, Rao BM. Discovery of Membrane-Permeating Cyclic Peptides via mRNA Display. Bioconjug Chem 2020; 31:2325-2338. [PMID: 32786364 DOI: 10.1021/acs.bioconjchem.0c00413] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Small synthetic peptides capable of crossing biological membranes represent valuable tools in cell biology and drug delivery. While several cell-penetrating peptides (CPPs) of natural or synthetic origin have been reported, no peptide is currently known to cross both cytoplasmic and outer embryonic membranes. Here, we describe a method to engineer membrane-permeating cyclic peptides (MPPs) with broad permeation activity by screening mRNA display libraries of cyclic peptides against embryos at different developmental stages. The proposed method was demonstrated by identifying peptides capable of permeating Drosophila melanogaster (fruit fly) embryos and mammalian cells. The selected peptide cyclo[Glut-MRKRHASRRE-K*] showed a strong permeation activity of embryos exposed to minimal permeabilization pretreatment, as well as human embryonic stem cells and a murine fibroblast cell line. Notably, in both embryos and mammalian cells, the cyclic peptide outperformed its linear counterpart and the control MPPs. Confocal microscopy and single cell flow cytometry analysis were utilized to assess the degree of permeation both qualitatively and quantitatively. These MPPs have potential application in studying and nondisruptively controlling intracellular or intraembryonic processes.
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Affiliation(s)
- John Bowen
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way room 2-009, Raleigh, North Carolina 27606, United States
| | - Allison E Schloop
- Genetics Program, North Carolina State University, 112 Derieux Place, Raleigh, North Carolina 27695, United States
| | - Gregory T Reeves
- Department of Chemical Engineering, Texas A&M University, 200 Jack E. Brown Engineering Building, College Station, Texas 77843, United States
| | - Stefano Menegatti
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way room 2-009, Raleigh, North Carolina 27606, United States
- Biomanufacturing Training and Education Center (BTEC), North Carolina State University, 850 Oval Drive, Raleigh, North Carolina 27606, United States
| | - Balaji M Rao
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way room 2-009, Raleigh, North Carolina 27606, United States
- Biomanufacturing Training and Education Center (BTEC), North Carolina State University, 850 Oval Drive, Raleigh, North Carolina 27606, United States
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3
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Narasimha S, Nagornov KO, Menin L, Mucciolo A, Rohwedder A, Humbel BM, Stevens M, Thum AS, Tsybin YO, Vijendravarma RK. Drosophila melanogaster cloak their eggs with pheromones, which prevents cannibalism. PLoS Biol 2019; 17:e2006012. [PMID: 30629594 PMCID: PMC6328083 DOI: 10.1371/journal.pbio.2006012] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 12/07/2018] [Indexed: 01/14/2023] Open
Abstract
Oviparous animals across many taxa have evolved diverse strategies that deter egg predation, providing valuable tests of how natural selection mitigates direct fitness loss. Communal egg laying in nonsocial species minimizes egg predation. However, in cannibalistic species, this very behavior facilitates egg predation by conspecifics (cannibalism). Similarly, toxins and aposematic signaling that deter egg predators are often inefficient against resistant conspecifics. Egg cannibalism can be adaptive, wherein cannibals may benefit through reduced competition and added nutrition, but since it reduces Darwinian fitness, the evolution of anticannibalistic strategies is rife. However, such strategies are likely to be nontoxic because deploying toxins against related individuals would reduce inclusive fitness. Here, we report how D. melanogaster use specific hydrocarbons to chemically mask their eggs from cannibal larvae. Using an integrative approach combining behavioral, sensory, and mass spectrometry methods, we demonstrate that maternally provisioned pheromone 7,11-heptacosadiene (7,11-HD) in the eggshell’s wax layer deters egg cannibalism. Furthermore, we show that 7,11-HD is nontoxic, can mask underlying substrates (for example, yeast) when coated upon them, and its detection requires pickpocket 23 (ppk23) gene function. Finally, using light and electron microscopy, we demonstrate how maternal pheromones leak-proof the egg, consequently concealing it from conspecific larvae. Our data suggest that semiochemicals possibly subserve in deceptive functions across taxa, especially when predators rely on chemical cues to forage, and stimulate further research on deceptive strategies mediated through nonvisual sensory modules. This study thus highlights how integrative approaches can illuminate our understanding on the adaptive significance of deceptive defenses and the mechanisms through which they operate. Egg-laying species that lack parental care often protect their eggs from predators by laying them in communal groups or by fortifying them with toxins. However, these strategies may backfire when the predators are from the same species (cannibals) since a) there are plenty of available eggs in these sites, b) the cannibals may be resistant to the toxins, and c) poisoning cannibals who may be related would reduce inclusive fitness. Under these circumstances, natural selection should favor anticannibalistic strategies that are likely to be nontoxic. Here, we investigate how fruit flies (Drosophila melanogaster), which oviposit communally, protect their eggs from cannibalism by their own larvae. We show that maternal hydrocarbons incorporated into the egg’s wax layer to make them waterproof interestingly also serve as a mask that conceals their identity from cannibal larvae. In particular, we identify one female sex pheromone that deters cannibalism by forming a layer around the egg to conceal it. We further demonstrate that this pheromone is nontoxic and can mask underlying substrates such as yeast when used as a coating. While deceptive strategies (such as camouflage) deployed to avoid predation are extensively studied from a visual perspective, our findings suggest that deceptive strategies operating through other nonvisual sensory systems might be equally common across taxa.
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Affiliation(s)
- Sunitha Narasimha
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | | | - Laure Menin
- Institute of Chemical Sciences and Engineering, EPFL, Lausanne, Switzerland
| | - Antonio Mucciolo
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Astrid Rohwedder
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Bruno M. Humbel
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Martin Stevens
- Centre for Ecology & Conservation, University of Exeter, United Kingdom
| | - Andreas S. Thum
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Yury O. Tsybin
- Spectroswiss Sàrl, EPFL Innovation Park, Lausanne, Switzerland
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Cortical movement of Bicoid in early Drosophila embryos is actin- and microtubule-dependent and disagrees with the SDD diffusion model. PLoS One 2017; 12:e0185443. [PMID: 28973031 PMCID: PMC5626467 DOI: 10.1371/journal.pone.0185443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/12/2017] [Indexed: 01/02/2023] Open
Abstract
The Bicoid (Bcd) protein gradient in Drosophila serves as a paradigm for gradient formation in textbooks. The SDD model (synthesis, diffusion, degradation) was proposed to explain the formation of the gradient. The SDD model states that the bcd mRNA is located at the anterior pole of the embryo at all times and serves a source for translation of the Bicoid protein, coupled with diffusion and uniform degradation throughout the embryo. Recently, the ARTS model (active RNA transport, synthesis) challenged the SDD model. In this model, the mRNA is transported at the cortex along microtubules to form a mRNA gradient which serves as template for the production of Bcd, hence little Bcd movement is involved. To test the validity of the SDD model, we developed a sensitive assay to monitor the movement of Bcd during early nuclear cycles. We observed that Bcd moved along the cortex and not in a broad front towards the posterior as the SDD model would have predicted. We subjected embryos to hypoxia where the mRNA remained strictly located at the tip at all times, while the protein was allowed to move freely, thus conforming to an ideal experimental setup to test the SDD model. Unexpectedly, Bcd still moved along the cortex. Moreover, cortical Bcd movement was sparse, even under longer hypoxic conditions. Hypoxic embryos treated with drugs compromising microtubule and actin function affected Bcd cortical movement and stability. Vinblastine treatment allowed the simulation of an ideal SDD model whereby the protein moved throughout the embryo in a broad front. In unfertilized embryos, the Bcd protein followed the mRNA which itself was transported into the interior of the embryo utilizing a hitherto undiscovered microtubular network. Our data suggest that the Bcd gradient formation is probably more complex than previously anticipated.
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Elalayli M, Hall JD, Fakhouri M, Neiswender H, Ellison TT, Han Z, Roon P, LeMosy EK. Palisade is required in the Drosophila ovary for assembly and function of the protective vitelline membrane. Dev Biol 2008; 319:359-69. [PMID: 18514182 DOI: 10.1016/j.ydbio.2008.04.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 03/15/2008] [Accepted: 04/26/2008] [Indexed: 11/17/2022]
Abstract
The innermost layer of the Drosophila eggshell, the vitelline membrane, provides structural support and positional information to the embryo. It is assembled in an incompletely understood manner from four major proteins to form a homogeneous, transparent extracellular matrix. Here we show that RNAi knockdown or genetic deletion of a minor constituent of this matrix, Palisade, results in structural disruptions during the initial synthesis of the vitelline membrane by somatic follicle cells surrounding the oocyte, including wide size variation among the precursor vitelline bodies and disorganization of follicle cell microvilli. Loss of Palisade or the microvillar protein Cad99C results in abnormal uptake into the oocyte of sV17, a major vitelline membrane protein, and defects in non-disulfide cross-linking of sV17 and sV23, while loss of Palisade has additional effects on processing and disulfide cross-linking of these proteins. Embryos surrounded by the abnormal vitelline membranes synthesized when Palisade is reduced are fertilized but undergo developmental arrest, usually during the first 13 nuclear divisions, with a nuclear phenotype of chromatin margination similar to that described for wild-type embryos subjected to anoxia. Our results demonstrate that Palisade is involved in coordinating assembly of the vitelline membrane and is required for functional properties of the eggshell.
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Affiliation(s)
- Maggie Elalayli
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA 30912, USA
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6
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Chill sensitivity and cryopreservation of eggs of the greater wax moth Galleria mellonella (Lepidoptera: Pyralidae). Cryobiology 2007; 56:1-7. [PMID: 17950266 DOI: 10.1016/j.cryobiol.2007.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 09/10/2007] [Accepted: 09/10/2007] [Indexed: 11/21/2022]
Abstract
There is an increasing need for methods of cryopreservation of arthropods. In particular, Lepidoptera are extremely important in entomological applications for the protection of agricultural crops and forest ecosystems and also in many aspects of biodiversity conservation. Yet, few studies have dealt with cryopreservation techniques in species of this insect order. The aim of this study was to examine the chill sensitivity of eggs of the greater wax moth Galleria mellonella (L.) and the possibility to cryopreserve the eggs by vitrification methods. One day-old eggs were dechlorinated with water solutions of 1.25% sodium hypochlorite and 0.04% Tween 80, treated with cryoprotective agents in two steps, subjected to rapid cooling by immersion in LN and stored in a mechanical freezer for 48 h at -140 degrees C. They exhibited survival rates of 1.6+/-0.5% after being cooled in LN and 0.6+/-0.2% after being stored in the mechanical freezer. 92.9% of the larvae that hatched from cryopreserved eggs completed development regularly, producing adults that bred and laid fertile eggs. The hatching rate of eggs in the F1 and F2 generations was higher than 90%. Adult emergences of the progeny of eggs stored at ultra-low temperatures allowed us to establish a laboratory colony.
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7
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Papassideri IS, Trougakos IP, Leonard KR, Margaritis LH. Structural and biochemical analysis of the Leptinotarsa decemlineata (Coleoptera; Chrysomeloidea) crystalline chorionic layer. JOURNAL OF INSECT PHYSIOLOGY 2003; 49:377-384. [PMID: 12769991 DOI: 10.1016/s0022-1910(03)00022-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The developmental aspects of the Leptinotarsa decemlineata crystalline chorionic layer (CCL) morphogenesis, its composition and its supramolecular structure were studied. The mature Leptinotarsa decemlineata eggshell consists of the vitelline membrane and the CCL, while the follicle cell remnants following their degeneration after oogenesis completion constitute the outer chorionic layer. The vitelline membrane and the CCL layers are formed through continuous material deposition from the follicular epithelium, whereas the main morphogenic factor during most insect eggshell formation, namely the follicle cell and oocyte microvilli, are seemingly involved only in vitelline membrane formation. Analysis of the CCL morphogenesis showed that this layer is assembled from a fiber-like pre-crystalline material, which accumulates at the vitelline membrane-follicle cell interface. The mature CCL is about 1 microm thick and exhibits a periodicity of approximately 10 nm, while computer image analysis studies of thin-sectioned CCL revealed the existence of crystalline layers parallel to the CCL surface. Finally, SDS-PAGE-electrophoresis of purified CCLs showed that this crystalline layer is of a proteinaceous nature and is most likely composed of 3-5 polypeptides with a molecular weight ranging in between 28-60 kDa. Overall, these data exemplify for the first time the nature and supramolecular arrangement of a crystalline layer and its constituent molecules in Coleoptera.
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Affiliation(s)
- Issidora S Papassideri
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Kouponia, 15782 Athens, Greece.
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8
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Wang WB, Leopold RA, Nelson DR, Freeman TP. Cryopreservation of Musca domestica (Diptera: Muscidae) embryos. Cryobiology 2000; 41:153-66. [PMID: 11034794 DOI: 10.1006/cryo.2000.2278] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prior studies on cryopreserving embryos of several non-drosophilid flies established that two Drosophila melanogaster embryo cryopreservation protocols were not directly suitable for use with these species. This paper describes our work on developing a protocol for cryopreservation of embryos of the housefly, Musca domestica. Significant progress was made when permeabilization of the vitelline membrane was optimized, a vitrification solution containing ethylene glycol, polyethylene glycol, and trehalose was formulated, and when cooling and recovery of the cryopreservation protocol included a step which passed the embryos through liquid nitrogen vapor. More than 70% of housefly embryos withstand treatments of dechorionation, permeabilization, loading with cryoprotectant, and dehydration in vitrification solution, but the cooling, warming, and poststorage rearing steps still cause a considerable reduction in survival. About 53% of the vitrified M. domestica embryos hatched into larvae. Relative to the percentage of the control adult emergence, about 13% of the embryos stored in liquid nitrogen developed into fertile adults. Hatching of the F(1) progeny of adults having been cryopreserved as embryos was similar to control levels.
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Affiliation(s)
- W B Wang
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota 58105, USA.
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Papassideri IS, Leonard KR, Mills D, Margaritis LH. Mass determination of the unit cell of the innermost chorionic layer in Drosophilidae by scanning transmission electron microscopy. J Struct Biol 1999; 127:258-62. [PMID: 10544051 DOI: 10.1006/jsbi.1999.4159] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The innermost chorionic layer (ICL) in eggshells of Drosophila melanogaster is a naturally occurring patchwork of thin three-dimensional crystalline plates located between the inner endochorion and the vitelline envelope. The mass-per-unit area of the ICL has been measured from scanning transmission electron microscope images of isolated unstained material and it was possible to distinguish up to four layers with the majority of the crystalline sheets being one to three layers thick. Taking into account the unit cell areas for the different crystals, we have estimated the mean ICL subunit sizes to be 36 kDa for Drosophila melanogaster, 35 kDa for Drosophila auraria, and 33 kDa for Drosophila teissieri. The results suggest that the three different Drosophilidae species have very similar average subunit masses.
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Affiliation(s)
- I S Papassideri
- Division of Cell Biology and Biophysics, University of Athens, Panepistimiopolis, Kouponia, Athens, 15701, Greece
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10
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Papassideri IS, Margaritis LH. The eggshell of Drosophila melanogaster: IX. Synthesis and morphogenesis of the innermost chorionic layer. Tissue Cell 1996; 28:401-9. [PMID: 8760855 DOI: 10.1016/s0040-8166(96)80026-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Synthesis and morphogenesis of the innermost chorionic layer (ICL) was investigated by conventional EM methods, freeze-fracturing, tissue culture in Robb's medium, and EM autoradiography. Both autoradiography and fine structure results have shown that ICL-components are secreted prior to other chorion proteins. Their secretion starts on stage 12a but the first layer of ICL molecules is visible at stage 12b. Its thickness is gradually increased during the next stages, taking first, a bilaminar form along with the inner endochorion. Later, at the end of choriogenesis, ICL is detached from the endochorion and takes its final thickness and configuration, consisting of a 3-dimensional crystal, about 40 nm thick. The isolated ICL in conditions of air water interface is a monolayer crystal 10 nm thick. Studies on chorion mutants showed that the amount of protein secreted by the follicle cells is independent to the process of crystallisation. These data show how a proteinaceous extracellular substance is gradually assembled to form a 3-D crystal and how it can be organised to perform functions such as the physiological resistance of the insect eggs against water loss or water uptake, whenever they are laid on substrates with extreme environmental conditions. These functions are performed by ICL in conjunction with the underlying wax layer.
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Affiliation(s)
- I S Papassideri
- Department of Biology, University of Athens, Panepistimiopolis, Greece.
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Papassideri IS, Margaritis LH, Gulik-Krzywicki T. The eggshell of Drosophila melanogaster. VIII. Morphogenesis of the wax layer during oogenesis. Tissue Cell 1993; 25:929-36. [PMID: 8140583 DOI: 10.1016/0040-8166(93)90041-i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Utilizing freeze-fracturing and conventional electron microscopy methods, we have studied the details of morphogenesis and construction of the wax layer envelope from Oregon R and mutants of Drosophila melanogaster eggs during oogenesis. The wax layer is synthesized and secreted by the follicular cells in the form of lipid vesicles during stage 10b. During secretion (stages 10b, 11 and 12) the lipid vesicles are accumulated on the vitelline membrane surface and become flat. At the late stages of choriogenesis (stages 13, 14) the lipid vesicles are compressed tightly between the vitelline membrane and the other already constructed eggshell layers, so the wax layer becomes very thin and is hardly seen in cross-fractured views.
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Affiliation(s)
- I S Papassideri
- Department of Biochemistry, Cell and Molecular Biology and Genetics, University of Athens, Greece
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12
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The fine structure of the eggshell of the laid egg of Locusta migratoria migratorioides. Tissue Cell 1993; 25:599-610. [PMID: 18621249 DOI: 10.1016/0040-8166(93)90012-a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/1991] [Revised: 03/08/1993] [Indexed: 11/22/2022]
Abstract
Ultrastructural analysis disclosed a regional diversification of the eggshell of the Locusta migratoria m. (L.m.m.) egg. This diversification is discussed taking into account the data about water permeability of the L.m.m. egg. The presence of several kinds of openings in the exochorion implies that in addition to the micropyles, the L.m.m. egg is provided with a respiratory system, especially in its anterior pole. The respiratory system of insect eggs is briefly reviewed. The presence of a wax layer in the L.m.m. egg is also discussed.
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