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Saeed A, Mehmood S, Zahoor MS, Khan EU, Usman M, Hashmi SGMD, Saleem K, Ahmad S. Comparative evaluation of different moulting methods on productive performance, egg quality, and antibody response of leghorn hens. Trop Anim Health Prod 2023; 55:304. [PMID: 37728634 DOI: 10.1007/s11250-023-03710-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/12/2023] [Indexed: 09/21/2023]
Abstract
The aim of the study was to compare three moulting procedures and their effect on productive performance, egg quality, and antibody response of leghorn hens. For this, a total of 324 laying hens were distributed into three treatment groups having 12 replicates of 9 birds each according to completely randomized design. Treatments consisted of three moulting procedures based on feed and light restriction. The targeted weight at the end of moulting was 1450-1470 g. As soon as the moulting procedure is complete, the comparative analysis of post-moult productive performance (feed intake, egg production, egg weight, egg mass, feed per dozen eggs, feed per kg egg mass, livability), egg quality characteristics (egg weight, egg length and width, shape index, surface area, volume, albumen height, weight, Haugh unit score, yolk width, height, index, egg shell pore number, shell weight, thickness, breaking strength), and antibody response against Newcastle disease and avian influenza (H-9) were evaluated. Birds subjected to moulting procedure 3 (8 days fasting and gradual decrease in light) showed improvement in productive performance, egg geometry and quality traits, and antibody response against Newcastle disease virus. Birds experienced moulting procedure 1 (11 days fasting) had improved feed intake, egg production, and livability. However, birds moulted with procedure 2 (6 days fasting) revealed intermediate result in all the studied parameters. In conclusion, moulting through feed and light restriction with 8 days fasting and gradual reduction in light has potential to improve performance of leghorn hens.
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Affiliation(s)
- Amir Saeed
- Department of Poultry Production, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Shahid Mehmood
- Department of Poultry Production, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Muhammad Shahid Zahoor
- Department of Poultry Production, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Ehsaan Ullah Khan
- Department of Animal Nutrition, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Muhammad Usman
- Department of Poultry Production, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Syed Ghulam Mohayud Din Hashmi
- Department of Wildlife and Ecology, Faculty of Fisheries and Wildlife, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Kinza Saleem
- Department of Animal Nutrition, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Sohail Ahmad
- Department of Poultry Production, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan.
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Rayan GN, Galal A, Fathi MM, Alawaid S, Shehata W, El-Attar AH. Assessing Differences in the Quality Properties and Ultrastructure of Eggshell as Affected by Chicken Strain and Flock Age During Incubation Period. BRAZILIAN JOURNAL OF POULTRY SCIENCE 2023. [DOI: 10.1590/1806-9061-2022-1647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- GN Rayan
- King Faisal University, Saudi Arabia; Ain Shams University, Egypt
| | | | - MM Fathi
- Ain Shams University, Egypt; Qassim University, Saudi Arabia
| | - S Alawaid
- King Faisal University, Saudi Arabia
| | - W Shehata
- King Faisal University, Saudi Arabia
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3
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Carroll C, Engström N, Nilsson PF, Haxen ER, Mohlin S, Berg P, Glud RN, Hammarlund EU. Hypoxia Generated by Avian Embryo Growth Induces the HIF-α Response and Critical Vascularization. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.675800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cancer research has transformed our view on cellular mechanisms for oxygen sensing. It has been documented that these mechanisms are important for maintaining animal tissues and life in environments where oxygen (O2) concentrations fluctuate. In adult animals, oxygen sensing is governed by the Hypoxia Inducible Factors (HIFs) that are stabilized at low oxygen concentrations (hypoxia). However, the importance of hypoxia itself during development and for the onset of HIF-driven oxygen sensing remains poorly explored. Cellular responses to hypoxia associates with cell immaturity (stemness) and proper tissue and organ development. During mammalian development, the initial uterine environment is hypoxic. The oxygenation status during avian embryogenesis is more complex since O2 continuously equilibrates across the porous eggshell. Here, we investigate HIF dynamics and use microelectrodes to determine O2 concentrations within the egg and the embryo during the first four days of development. To determine the increased O2 consumption rates, we also obtain the O2 transport coefficient (DO2) of eggshell and associated inner and outer shell membranes, both directly (using microelectrodes in ovo for the first time) and indirectly (using water evaporation at 37.5°C for the first time). Our results demonstrate a distinct hypoxic phase (<5% O2) between day 1 and 2, concurring with the onset of HIF-α expression. This phase of hypoxia is demonstrably necessary for proper vascularization and survival. Our indirectly determined DO2 values are about 30% higher than those determined directly. A comparison with previously reported values indicates that this discrepancy may be real, reflecting that water vapor and O2 may be transported through the eggshell at different rates. Based on our obtained DO2 values, we demonstrate that increased O2 consumption of the growing embryo appears to generate the phase of hypoxia, which is also facilitated by the initially small gas cell and low membrane permeability. We infer that the phase of in ovo hypoxia facilitates correct avian development. These results support the view that hypoxic conditions, in which the animal clade evolved, remain functionally important during animal development. The study highlights that insights from the cancer field pertaining to the cellular capacities by which both somatic and cancer cells register and respond to fluctuations in O2 concentrations can broadly inform our exploration of animal development and success.
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Vieco‐Galvez D, Castro I, Morel PCH, Chua WH, Loh M. The eggshell structure in apteryx; form, function, and adaptation. Ecol Evol 2021; 11:3184-3202. [PMID: 33841776 PMCID: PMC8019059 DOI: 10.1002/ece3.7266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/09/2021] [Accepted: 01/15/2021] [Indexed: 11/22/2022] Open
Abstract
Apteryx is a genus of flightless birds endemic to New Zealand known to lay very large eggs in proportion to body weight. The eggshell of Apteryx is unusually thin and less porous than allometrically expected possibly as a compensation for a very long incubation period. Past studies have been carried out on Apteryx australis, a species which once comprised all kiwi with brown plumage, now separated into three distinct species. These species use different habitats and live at different latitudes and altitudes, therefore generating a need to revise our knowledge of the attributes of their eggshells. In this study, we measured the physical characteristics and water conductance on eggshell fragments of these three species and Great-spotted Kiwi and relate them to the environmental conditions of their respective environments; we also measured the water vapor conductance of Brown Kiwi eggs of late stages of incubation. We found that several trade-offs exist between incubation behavior, environmental conditions, and eggshell structure. We found differences between species in eggshell water vapor conductance seemingly related to altitude; Brown Kiwi and Rowi generally inhabiting lower altitudes had the highest conductance and Tokoeka, generally living in montane environments, the lowest. This is achieved by an increased eggshell thickness rather than a pore area reduction. Finally, the water vapor conductance late in incubation was 58% higher than infertile unincubated eggs, suggesting a drastic increase in conductance throughout the long incubation period. Using the values previously reported, we calculated the embryonic eggshell thinning to be 32.5% at the equatorial region of the eggshell. We describe several new features, such as triangular mineral particles in the cuticle, reported for the extinct Trigonoolithus amoei, and confirmed the existence of plugged pores. We suggest that these structures provide microbial protection needed by a burrow nesting species with a long incubation period.
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Affiliation(s)
- David Vieco‐Galvez
- School of Agriculture and EnvironmentMassey UniversityPalmerston NorthNew Zealand
| | - Isabel Castro
- School of Agriculture and EnvironmentMassey UniversityPalmerston NorthNew Zealand
| | - Patrick C. H. Morel
- School of Agriculture and EnvironmentMassey UniversityPalmerston NorthNew Zealand
| | - Wei Hang Chua
- School of Health SciencesMassey UniversityPalmerston NorthNew Zealand
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5
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Whitaker-Fornek JR, Nelson JK, Lybbert CW, Pilarski JQ. Development and regulation of breathing rhythms in embryonic and hatchling birds. Respir Physiol Neurobiol 2019; 269:103246. [DOI: 10.1016/j.resp.2019.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/19/2019] [Accepted: 06/23/2019] [Indexed: 11/28/2022]
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6
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The antioxidant properties of canthaxanthin and its potential effects in the poultry eggs and on embryonic development of the chick. Part 1. WORLD POULTRY SCI J 2019. [DOI: 10.1017/s0043933912000578] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Jackson D, Thompson JE, Hemmings N, Birkhead TR. Common guillemot ( Uria aalge) eggs are not self-cleaning. ACTA ACUST UNITED AC 2018; 221:jeb.188466. [PMID: 30322981 DOI: 10.1242/jeb.188466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/03/2018] [Indexed: 11/20/2022]
Abstract
Birds are arguably the most evolutionarily successful extant vertebrate taxon, in part because of their ability to reproduce in virtually all terrestrial habitats. Common guillemots, Uria aalge, incubate their single egg in an unusual and harsh environment; on exposed cliff ledges, without a nest, and in close proximity to conspecifics. As a consequence, the surface of guillemot eggshells is frequently contaminated with faeces, dirt, water and other detritus, which may impede gas exchange or facilitate microbial infection of the developing embryo. Despite this, guillemot chicks survive incubation and hatch from eggs heavily covered with debris. To establish how guillemot eggs cope with external debris, we tested three hypotheses: (1) contamination by debris does not reduce gas exchange efficacy of the eggshell to a degree that may impede normal embryo development; (2) the guillemot eggshell surface is self-cleaning; (3) shell accessory material (SAM) prevents debris from blocking pores, allowing relatively unrestricted gas diffusion across the eggshell. We showed that natural debris reduces the conductance of gases across the guillemot eggshell by blocking gas exchange pores. Despite this problem, we found no evidence that guillemot eggshells are self-cleaning, but instead showed that the presence of SAM on the eggshell surface largely prevents pore blockages from occurring. Our results demonstrate that SAM is a crucial feature of the eggshell surface in a species with eggs that are frequently in contact with debris, acting to minimise pore blockages and thus ensure a sufficient rate of gas diffusion for embryo development.
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Affiliation(s)
- Duncan Jackson
- Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Jamie E Thompson
- Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Nicola Hemmings
- Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Timothy R Birkhead
- Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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8
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Abstract
Why are avian eggs ovoid, while the eggs of most other vertebrates are symmetrical? The interaction between an egg and its environment likely drives selection that will shape eggs across evolutionary time. For example, eggs incubated in hot, arid regions face acute exposure to harsh climatic conditions relative to those in temperate zones, and this exposure will differ across nest types, with eggs in open nests being more exposed to direct solar radiation than those in enclosed nests. We examined the idea that the geographical distribution of both egg shapes and nest types should reflect selective pressures of key environmental parameters, such as ambient temperature and the drying capacity of air. We took a comparative approach, using 310 passerine species from Australia, many of which are found in some of the most extreme climates on earth. We found that, across the continent, egg elongation decreases and the proportion of species with domed nests with roofs increases in hotter and drier areas with sparse plant canopies. Eggs are most spherical in open nests in the hottest environments, and most elongate in domed nests in wetter, shadier environments. Our findings suggest that climatic conditions played a key role in the evolution of passerine egg shape.
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Lane SJ, Moran AL, Shishido CM, Tobalske BW, Woods HA. Cuticular gas exchange by Antarctic sea spiders. J Exp Biol 2018; 221:jeb.177568. [DOI: 10.1242/jeb.177568] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/16/2018] [Indexed: 11/20/2022]
Abstract
Many marine organisms and life stages lack specialized respiratory structures, like gills, and rely instead on cutaneous respiration, which they facilitate by having thin integuments. This respiratory mode may limit body size, especially if the integument also functions in support or locomotion. Pycnogonids, or sea spiders, are marine arthropods that lack gills and rely on cutaneous respiration but still grow to large sizes. Their cuticle contains pores, which may play a role in gas exchange. Here, we examined alternative paths of gas exchange in sea spiders: 1) oxygen diffuses across pores in the cuticle, a common mechanism in terrestrial eggshells, 2) oxygen diffuses directly across the cuticle, a common mechanism in small aquatic insects, or 3) oxygen diffuses across both pores and cuticle. We examined these possibilities by modeling diffusive oxygen fluxes across all pores in the body of sea spiders and asking whether those fluxes differed from measured metabolic rates. We estimated fluxes across pores using Fick's law parameterized with measurements of pore morphology and oxygen gradients. Modeled oxygen fluxes through pores closely matched oxygen consumption across a range of body sizes, which means the pores facilitate oxygen diffusion. Furthermore, pore volume scaled hypermetrically with body size, which helps larger species facilitate greater diffusive oxygen fluxes across their cuticle. This likely presents a functional trade-off between gas exchange and structural support, in which cuticle must be thick enough to prevent buckling due to external forces but porous enough to allow sufficient gas exchange.
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Affiliation(s)
- Steven J. Lane
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA
| | - Amy L. Moran
- Department of Biology, University of Hawai'i at Mānoa, Honolulu, Hawai'i 96822, USA
| | - Caitlin M. Shishido
- Department of Biology, University of Hawai'i at Mānoa, Honolulu, Hawai'i 96822, USA
| | - Bret W. Tobalske
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA
| | - H. Arthur Woods
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA
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Chin SY, Hopkins WA, Cristol DA. Mercury alters initiation and construction of nests by zebra finches, but not incubation or provisioning behaviors. ECOTOXICOLOGY (LONDON, ENGLAND) 2017; 26:1271-1283. [PMID: 29022240 DOI: 10.1007/s10646-017-1852-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
Mercury is an environmental contaminant that impairs avian reproduction, but the behavioral and physiological mechanisms underlying this effect are poorly understood. The objective of this study was to determine whether lifetime dietary exposure to mercury (1.2 µg/g wet weight in food) impacted avian parental behaviors, and how this might influence reproductive success. To distinguish between the direct effects of mercury on parents and offspring, we created four treatment groups of captive-bred zebra finches (Taeniopygia guttata), with control and mercury-exposed adults raising cross-fostered control or mercury-exposed eggs (from maternal transfer). Control parents were 23% more likely to fledge young than parents exposed to mercury, regardless of egg exposure. Mercury-exposed parents were less likely to initiate nests than controls and spent less time constructing them. Nests of mercury-exposed pairs were lighter, possibly due to an impaired ability to bring nest material into the nestbox. However, nest temperature, incubation behavior, and provisioning rate did not differ between parental treatments. Unexposed control eggs tended to have shorter incubation periods and higher hatching success than mercury-exposed eggs, but there was no effect of parental exposure on these parameters. We accidentally discovered that parent finches transfer some of their body burden of mercury to nestlings during feeding through secretion in the crop. These results suggest that, in mercury-exposed songbirds, pre-laying parental behaviors, combined with direct exposure of embryos to mercury, likely contribute to reduced reproductive success and should be considered in future studies. Further research is warranted in field settings, where parents are exposed to greater environmental challenges and subtle behavioral differences might have more serious consequences than were observed in captivity.
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Affiliation(s)
- Stephanie Y Chin
- Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - William A Hopkins
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Daniel A Cristol
- Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA.
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11
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Weber T, Selzer PM. Isoxazolines: A Novel Chemotype Highly Effective on Ectoparasites. ChemMedChem 2016; 11:270-6. [DOI: 10.1002/cmdc.201500516] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 12/09/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Tina Weber
- Marie Curie Initial Training Network “ParaMet”; Institute of Infection, Immunity and Inflammation; University of Glasgow; Glasgow UK
| | - Paul M. Selzer
- Boehringer Ingelheim Animal Health GmbH; Binger Straße 173 55216 Ingelheim am Rhein Germany
- Universität Tübingen; Interfakultäres Institut für Biochemie; Tübingen Germany
- Wellcome Trust Centre for Molecular Parasitology; Institute of Infection, Immunity and Inflammation; Faculty of Biomedical & Life Sciences; University of Glasgow; Glasgow UK
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12
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Portugal SJ, Maurer G, Thomas GH, Hauber ME, Grim T, Cassey P. Nesting behaviour influences species-specific gas exchange across avian eggshells. ACTA ACUST UNITED AC 2015; 217:3326-32. [PMID: 25232199 PMCID: PMC4179895 DOI: 10.1242/jeb.103291] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carefully controlled gas exchange across the eggshell is essential for the development of the avian embryo. Water vapour conductance (GH2O) across the shell, typically measured as mass loss during incubation, has been demonstrated to optimally ensure the healthy development of the embryo while avoiding desiccation. Accordingly, eggs exposed to sub-optimal gas exchange have reduced hatching success. We tested the association between eggshell GH2O and putative life-history correlates of adult birds, ecological nest parameters and physical characteristics of the egg itself to investigate how variation in GH2O has evolved to maintain optimal water loss across a diverse set of nest environments. We measured gas exchange through eggshell fragments in 151 British breeding bird species and fitted phylogenetically controlled, general linear models to test the relationship between GH2O and potential predictor parameters of each species. Of our 17 life-history traits, only two were retained in the final model: wet-incubating parent and nest type. Eggs of species where the parent habitually returned to the nest with wet plumage had significantly higher GH2O than those of parents that returned to the nest with dry plumage. Eggs of species nesting in ground burrows, cliffs and arboreal cups had significantly higher GH2O than those of species nesting on the ground in open nests or cups, in tree cavities and in shallow arboreal nests. Phylogenetic signal (measured as Pagel's λ) was intermediate in magnitude, suggesting that differences observed in the GH2O are dependent upon a combination of shared ancestry and species-specific life history and ecological traits. Although these data are correlational by nature, they are consistent with the hypothesis that parents constrained to return to the nest with wet plumage will increase the humidity of the nest environment, and the eggs of these species have evolved a higher GH2O to overcome this constraint and still achieve optimal water loss during incubation. We also suggest that eggs laid in cup nests and burrows may require a higher GH2O to overcome the increased humidity as a result from the confined nest microclimate lacking air movements through the nest. Taken together, these comparative data imply that species-specific levels of gas exchange across avian eggshells are variable and evolve in response to ecological and physical variation resulting from parental and nesting behaviours.
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Affiliation(s)
- Steven J Portugal
- Structure and Motion Laboratory, The Royal Veterinary College, University of London, North Mymms, Hatfield, Herts AL9 7TA, UK
| | - Golo Maurer
- School of Earth and Environmental Sciences, University of Adelaide, SA 5005 Australia
| | - Gavin H Thomas
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Mark E Hauber
- Department of Psychology, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, NY 10065, USA
| | - Tomáš Grim
- Department of Zoology and Laboratory of Ornithology, Palacký University, Olomouc, CZ-771 46 Czech Republic
| | - Phillip Cassey
- School of Earth and Environmental Sciences, University of Adelaide, SA 5005 Australia
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13
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van der Pol C, van Roovert-Reijrink I, Maatjens C, van den Brand H, Molenaar R. Effect of relative humidity during incubation at a set eggshell temperature and brooding temperature posthatch on embryonic mortality and chick quality. Poult Sci 2013; 92:2145-55. [DOI: 10.3382/ps.2013-03006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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14
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Tøien Ø. Automated open flow respirometry in continuous and long-term measurements: design and principles. J Appl Physiol (1985) 2013; 114:1094-107. [PMID: 23349455 DOI: 10.1152/japplphysiol.01494.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sustaining high-quality respirometry measurements on animals for estimating metabolic rate and fuel use is challenging. I present a general discussion and selected methods for automated measurements spanning over >4 mo with little need for adjustments or maintenance. 1) Lack of compensation for respiratory volume change may cause 6% error in the results on a fasting animal. The Haldane transformation provides the simplest calculation method for both O(2) and CO(2) measurements. 2) Use of Nafion tube dryers configured as countercurrent moisture exchangers provides maintenance-free drying of gases, with typical outlet dew points at -25 to -38°C and no CO(2) adsorption. The accuracy is improved by low dead space, making it feasible to pass gases though the same dryer. 3) A software algorithm employing a triple interpolation technique allows corrections for automated calibrations of O(2) and CO(2) with both zero-reference and span gas. 4) Burning known amounts of 100% ethanol provides total system verification of both O(2) consumption and respiratory quotient. A calculation method to supply instant CO(2) calibration gas from an alcohol burn is presented. 5) Automatic flow switching triggered by low/high O(2) thresholds improves accuracy of measurements and safety for the animals experiencing large ranges of O(2) consumption; this is a special requirement for recording metabolism in small hibernating mammals.
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Affiliation(s)
- Øivind Tøien
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA.
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15
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Evolution and development of fetal membranes and placentation in amniote vertebrates. Respir Physiol Neurobiol 2011; 178:39-50. [DOI: 10.1016/j.resp.2011.03.029] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/29/2011] [Accepted: 03/29/2011] [Indexed: 01/20/2023]
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16
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Portugal SJ, Maurer G, Cassey P. Eggshell permeability: a standard technique for determining interspecific rates of water vapor conductance. Physiol Biochem Zool 2010; 83:1023-31. [PMID: 20939733 DOI: 10.1086/656287] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Typically, eggshell water vapor conductance is measured on whole eggs, freshly collected at the commencement of a study. At times, however, it may not be possible to obtain whole fresh eggs but rather egg fragments or previously blown eggs. Here we evaluate and describe in detail a technique for modern laboratory analysis of eggshell conductance that uses fragments from fresh and museum eggs to determine eggshell water vapor conductance. We used fresh unincubated eggs of domesticated chickens (Gallus gallus domesticus), ducks (Anas platyrhynchos domesticus), and guinea fowl (Numida meleagris) to investigate the reliability, validity, and repeatability of the technique. To assess the suitability of museum samples, museum and freshly collected black-headed gull eggs (Larus ridibundus) were used. Fragments were cut out of the eggshell from the blunt end (B), equator (E), and pointy end (P). Eggshell fragments were glued to the top of a 0.25-mL micro test tube (Eppendorf) filled with 200 μL of distilled water and placed in a desiccator at 25°C. Eppendorfs were weighed three times at 24-h intervals, and mass loss was assumed to be a result of water evaporation. We report the following results: (1) mass loss between weighing sessions was highly repeatable and consistent in all species; (2) the majority of intraspecific variability in eggshell water vapor conductance between different eggs of the same species was explained through the differences in water vapor conductance between the three eggshell parts of the same egg (B, E, and P); (3) the technique was sensitive enough to detect significant differences between the three domestic species; (4) there was no overall significant difference between water vapor conductance of museum and fresh black-headed gull eggs; (5) there was no significant difference in water vapor conductance for egg fragments taken from the same egg both between different trials and within the same trial. We conclude, therefore, that this technique is an effective way of measuring interspecific water vapor conductance from eggshell fragments and that museum eggs are a suitable resource for such work.
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Affiliation(s)
- Steven J Portugal
- Centre for Ornithology, School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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17
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18
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Gas exchange in avian embryos and hatchlings. Comp Biochem Physiol A Mol Integr Physiol 2009; 153:359-77. [DOI: 10.1016/j.cbpa.2009.02.041] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/26/2009] [Accepted: 02/28/2009] [Indexed: 11/21/2022]
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19
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Rodríguez-Bustamante E, Sánchez S. Microbial Production of C13-Norisoprenoids and Other Aroma Compounds via Carotenoid Cleavage. Crit Rev Microbiol 2008; 33:211-30. [PMID: 17653988 DOI: 10.1080/10408410701473306] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Carotenoids are important precursors of a variety of compounds: the C(20)-retinoids, the C(15)-phytohormones, and the C(9)- to C(13)-aromas. Among the last type, C(13)-carotenoid-derived compounds (norterpenoids/norisoprenoids) such as ionones and damascones, constitute an essential aroma note in tea, grapes, roses, tobacco, and wine. Extraction of carotenoid-derived aroma compounds from plant sources is not economically realistic or considerably expensive. The biotechnological production of aroma compounds represents a feasible alternative and offers the production of enantiomerically pure molecules which can be labeled as "natural." To date, research in the production of ionones or the C(10)-compound, safranal, has mainly been focused on plant dioxygenases that cleave carotenoids in the positions between carbons 9 and 10 (9'-10') or 7 and 8 (7'-8'), respectively. Although relatively little is known about the microbial conversion of carotenoids into compounds with aroma due to the well known advantages of manipulating microorganisms, the aim of this work is to review the current state of the research in microbial production of norisoprenoids and other aroma compounds derived from carotenoid cleavage.
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Affiliation(s)
- E Rodríguez-Bustamante
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, DF, Mexico.
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Ibrahim HR, Hoq MI, Aoki T. Ovotransferrin possesses SOD-like superoxide anion scavenging activity that is promoted by copper and manganese binding. Int J Biol Macromol 2007; 41:631-40. [DOI: 10.1016/j.ijbiomac.2007.08.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 08/22/2007] [Accepted: 08/22/2007] [Indexed: 11/26/2022]
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Wallace BP, Sotherland PR, Spotila JR, Reina RD, Franks BF, Paladino FV. Biotic and Abiotic Factors Affect the Nest Environment of Embryonic Leatherback Turtles, Dermochelys coriacea. Physiol Biochem Zool 2004; 77:423-32. [PMID: 15286916 DOI: 10.1086/420951] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2003] [Indexed: 11/03/2022]
Abstract
Clutches of leatherback turtles, Dermochelys coriacea, have lower hatching success than those of other sea turtles, but causes of high embryonic mortality are unknown. We measured characteristics of clutches along with spatial and temporal changes in PO(2) and temperature during incubation to determine the extent to which they affected the developmental environment of leatherback embryos. Minimum PO(2) in nests decreased as both the total number and mass of metabolizing embryos increased. Increases in both the number and mass of metabolizing embryos caused an increase in maximum nest temperature. However, neither PO(2) nor temperature was correlated with hatching success. Our measurements of relatively high nest PO(2) (lowest 17.1 kPa or 16.9% O(2)) indicate that hypoxia apparently does not cause the low hatching success of leatherback clutches. Oxygen partial pressure increased and temperature decreased from the center toward the periphery of leatherback nests. We inferred from these measurements that positions of eggs within nests vary in quality and potentially affect overall developmental success of entire clutches. The large metabolic mass of leatherback clutches and limits to gas flux imposed by the sand create a situation in which leatherback embryos collectively affect their own environment.
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Affiliation(s)
- Bryan P Wallace
- Department of Bioscience and Biotechnology, Drexel University, Philadelphia, Pennsylvania 19104, USA
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Dzialowski EM, Sotherland PR. Maternal effects of egg size on emu Dromaius novaehollandiae egg composition and hatchling phenotype. ACTA ACUST UNITED AC 2004; 207:597-606. [PMID: 14718503 DOI: 10.1242/jeb.00792] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Parental investment in eggs and, consequently, in offspring can profoundly influence the phenotype, survival and ultimately evolutionary fitness of an organism. Avian eggs are excellent model systems to examine maternal allocation of energy translated through egg size variation. We used the natural range in emu Dromaius novaehollandiae egg size, from 400 g to >700 g, to examine the influence of maternal investment in eggs on the morphology and physiology of hatchlings. Female emus provisioned larger eggs with a greater absolute amount of energy, nutrients and water in the yolk and albumen. Variation in maternal investment was reflected in differences in hatchling size, which increased isometrically with egg size. Egg size also influenced the physiology of developing emu embryos, such that late-term embryonic metabolic rate was positively correlated with egg size and embryos developing in larger eggs consumed more yolk during development. Large eggs produced hatchlings that were both heavier (yolk-free wet and dry mass) and structurally larger (tibiotarsus and culmen lengths) than hatchlings emerging from smaller eggs. As with many other precocial birds, larger hatchlings also contained more water, which was reflected in a greater blood volume. However, blood osmolality, hemoglobin content and hematocrit did not vary with hatchling mass. Emu maternal investment in offspring, measured by egg size and composition, is significantly correlated with the morphology and physiology of hatchlings and, in turn, may influence the success of these organisms during the first days of the juvenile stage.
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Affiliation(s)
- Edward M Dzialowski
- Department of Biological Sciences, University of North Texas, PO Box 305220, Denton, TX 76203, USA.
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Zhao X, Salgado VL, Yeh JZ, Narahashi T. Differential actions of fipronil and dieldrin insecticides on GABA-gated chloride channels in cockroach neurons. J Pharmacol Exp Ther 2003; 306:914-24. [PMID: 12766256 DOI: 10.1124/jpet.103.051839] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fipronil and dieldrin are known to inhibit GABA receptors in both mammals and insects. However, the mechanism of selective toxicity of these insecticides between mammals and insects remains to be seen. One possible mechanism is that insect GABA receptors are more sensitive than mammalian GABAA receptors to fipronil and dieldrin. We examined differential actions of fipronil and dieldrin on GABA-gated chloride channels in insects and compared them with the data on mammalian GABAA receptors. Neurons were acutely dissociated from the American cockroach thoracic ganglia, and currents evoked by GABA were recorded by the whole-cell patch-clamp technique. GABA-evoked currents were carried by chloride ions, blocked by picrotoxinin, but not by bicuculline. Fipronil inhibited GABA currents with an IC50 value of 28 nM, whereas dieldrin exhibited a dual action potentiation with an EC50 value of 4 nM followed by inhibition with an IC50 value of 16 nM. Fipronil and dieldrin acted on the resting receptor at comparable rates, whereas fipronil blocked the activated receptor 10 times faster than dieldrin. Fipronil inhibition was partially reversible, whereas dieldrin inhibition was irreversible. Fipronil was 59 times more potent on cockroach GABA receptors than on rat GABAA receptors. However, the potentiating and inhibitory potencies of dieldrin in cockroach GABA receptors were comparable with those in rat GABAA receptors. It was concluded that the higher toxicity of fipronil in insects than in mammals is due partially to the higher sensitivity of GABA receptors. The mechanism of dieldrin's selective toxicity must lie in factors other than the sensitivity of GABA receptors.
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Affiliation(s)
- Xilong Zhao
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, IL 60611-3008, USA
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Pearson JT, Seymour RS, Baudinette RV, Runciman S. Respiration and energetics of embryonic development in a large altricial bird, the Australian pelican (Pelecanus conspicillatus). J Exp Biol 2002; 205:2925-33. [PMID: 12177157 DOI: 10.1242/jeb.205.18.2925] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
We examined whether the previously reported low cost of embryonic development in pelicans could be attributed to a more efficient conversion of egg energy to hatchling tissues as a result of high initial egg water content,low embryonic metabolic rate and growth later in incubation than in more precocious species. We therefore determined egg and hatchling composition and the development of embryonic respiration in the Australian pelican Pelecanus conspicillatus, which lays one of the largest eggs (140-210 g) with an altricial developmental mode. The small yolk fraction (21%) is typical of all pelecaniforms; however, we found that intraspecific variability in fresh egg mass was related to water content (principally in the albumen),but independent of yolk mass (mean 13 g dry mass). P. conspicillatuseggs have, on average, 635 kJ of energy, irrespective of egg mass across the whole range of egg mass.
The embryonic developmental pattern of O2 consumption and CO2 production showed clear plateaus lasting 2-3 days immediately prior to internal pipping, resembling the typical precocial pattern. However,the rate of pre-internal pipping O2 consumption was low in comparison with that of precocial species of similar egg mass. There is no evidence to support the hypothesis that the observed plateau in rates of O2 uptake is due to a diffusion limitation of the eggshell gas conductance in this species. Embryonic metabolic rate nearly doubled during the pipping period, but the mass-independent metabolic rate of the hatchling was low in comparison with that of the resting adult. The total O2consumed (11 063 ml) is equivalent to 217.3 kJ (or 34% of egg energy) based on indirect calorimetry and the observed respiratory exchange ratio of 0.71. Thus, the cost of development (direct calorimetry) was 0.29 kJ J-1in the egg (mean egg mass 168 g), which is one of lowest reported values. As a result, the production efficiency of pelican embryonic development was 61.6%,higher than the average for birds in general (56.9%) and, in particular, of seabirds that have prolonged incubation periods on the basis of egg mass. High efficiency in embryonic development in this species was attained as a result of rapid embryonic growth later in incubation, low hatchling energy density(23.6 kJ g-1 dry matter) and dry matter content, low embryonic metabolic rate throughout incubation and a shorter than expected incubation period of 33 days (predicted 36 days).
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Affiliation(s)
- James T Pearson
- Department of Environmental Biology, University of Adelaide, South Australia.
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Wolff MA, Wingate VP. Characterization and comparative pharmacological studies of a functional gamma-aminobutyric acid (GABA) receptor cloned from the tobacco budworm, Heliothis virescens (Noctuidae:Lepidoptera). INVERTEBRATE NEUROSCIENCE : IN 1998; 3:305-15. [PMID: 10212398 DOI: 10.1007/bf02577690] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper reports the functional expression and pharmacological characterization of a full length complementary deoxyribonucleic acid (cDNA) (pIVY12) cloned from a Heliothis virescens fertilized egg cDNA library that encodes for a gamma-aminobutyric acid (GABA) receptor subunit (HVRDL-Ser 285). Two electrode voltage clamp recordings of Xenopus oocytes expressing the HVRDL GABA-gated chloride channel revealed robust chloride ion conductance in response to GABA and the GABAA receptor agonist, muscimol. Baclofen, a GABAB agonist had no effect. Phenobarbital showed a positive dose-dependent allosteric modulatory effect, whereas the benzodiazepine, flunitrazepam, had no effect. Chloride conductance was depressed by the novel insecticide, fipronil ((+/-)-5-amino-1-(2,6 dichloro-alpha, alpha, alpha-trifluoro-p-tolyl)-4-trifluoromethyl-sulfinylpyrazole-3-carb onitrile) and the GABAA antagonist, picrotoxinin. The HVRDL GABA receptor was insensitive to blockage by dieldrin and the GABAA antagonist, bicuculline. The comparative actions of fipronil, picrotoxinin and dieldrin were examined on oocytes expressing the H. virescens wild-type (HVRDL-Ser 285), the site-directed mutant (HVRDL-Ala 285), the Drosophila melanogaster Rdl wild-type (DMRDL-Ala 302) and the Rdl dieldrin resistant (DMRDL-Ser 302) homo-oligomeric GABA receptors. HVRDL-Ala 285 was 15-fold more sensitive to blockage by fipronil than HVRDL-Ser 285. DMRDL-Ala 302 and DMRDL-Ser-302 showed a similar level of sensitivity to blockage by fipronil. HVRDL-Ser 285 and DMRDL-Ser 302 exhibited a similar level of insensitivity to picrotoxinin. HVRDL-Ala 285 and DMRDL-Ala 302 showed a similar range of picrotoxinin sensitivity. DMRDL-Ala 302 and HVRDL-Ala 285 showed some sensitivity to blockage by dieldrin. Fipronil sensitivity was significantly altered by the serine to alanine mutation at position 285 in the M2 region of the HVRDL subunit, whereas no difference was observed between the DMRDL-Ser 302 and DMRDL-Ala 302 receptors.
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Affiliation(s)
- M A Wolff
- Biochemistry-Biotechnology Group, Rhône-Poulenc Ag Company, Research Triangle Park, NC 27709, USA
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Veicsteinas A, Belleri M, Cinquetti A, Parolini S, Barbato G, Molinari Tosatti MP. Development of chicken embryos exposed to an intermittent horizontal sinusoidal 50 Hz magnetic field. Bioelectromagnetics 1996; 17:411-24. [PMID: 8915551 DOI: 10.1002/(sici)1521-186x(1996)17:5<411::aid-bem9>3.0.co;2-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effects of intermittent exposure (2 h on/22 h off) to a 200 microT horizontal, sinusoidally oscillating (50 Hz) magnetic field were studied in 210 fertilized chicken eggs. Two hundred ten control eggs (sham-exposed) were incubated in the same chamber as the experimental eggs. Chick embryos were examined for developmental anomalies and maturity stage after 48 h of incubation. Immunohistochemical analysis of extracellular membrane components (laminin, fibronectin, and type IV collagen) were conducted on day 7 and histological examinations for malformations of brain, liver, and heart, on days 7, 12, and 18 of incubation. Furthermore, egg fertility and egg weights were evaluated on days 2, 7, 12, and 18. The investigation also measured the body weight of chickens for 90 days from hatching and included histological analysis of body organs. Each variable was investigated blind. Statistical comparison between exposed and sham-exposed values did not show significant differences in any of the variables investigated. Thus, it appears that the exposure of embryos to an intermittent 200 microT magnetic field at 50 Hz does not cause developmental anomalies, changes in maturity stage, alterations in distribution of extracellular membrane components, or malformations in the brain, liver, or heart. Moreover, there were no differences in body weight, morphology, or histology of central nervous system, liver, heart, or testis in 90-day-old chickens hatched from exposed in comparison to sham-exposed eggs.
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Affiliation(s)
- A Veicsteinas
- Department of Biomedical Sciences and Biotechnologies, University of Brescia, Italy
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Visser GH, Zeinstra EC, van Gasteren F, Beintema AJ. Gas conductance and metabolism of shorebird eggs: variation within and between species. RESPIRATION PHYSIOLOGY 1995; 99:273-81. [PMID: 7777710 DOI: 10.1016/0034-5687(94)00097-j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fresh egg mass (M0; g), water vapor conductance of the egg shell (GH2O; mg.[Torr.d]-1), and neonate mass (Mn; g) were measured in the ruff (Philomachus pugnax), common redshank (Tringa totanus), northern lapwing (Vanellus vanellus), black-tailed godwit (Limosa limosa), and Eurasian curlew (Numenius arquata). In addition, the development of embryonic O2 consumption (MO2; ml.d-1) and CO2 production (MCO2; ml.d-1) were measured in these species, except the ruff. In northern lapwing and black-tailed godwit eggs the coefficients of variation for GH2O were 3.8 and 2.3 times higher, respectively, than those for M0. In these two species only about 10% of the variation for GH2O was attributable to M0, and about 77% to differences between clutches, suggesting a strong maternal component. In the northern lapwing, embryonic MO2 plateaued prior to internal pipping, but not in the common redshank and black-tailed godwit. The latter result is in contrast to embryonic patterns previously described for other precocial species. In shorebirds the occurrence of an embryonic MO2 plateau is not related to the neonatal level of cold-induced thermogenesis.
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Affiliation(s)
- G H Visser
- Department of Veterinary Basic Sciences, University of Utrecht, Netherlands
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Ffrench-Constant RH, Rocheleau TA, Steichen JC, Chalmers AE. A point mutation in a Drosophila GABA receptor confers insecticide resistance. Nature 1993; 363:449-51. [PMID: 8389005 DOI: 10.1038/363449a0] [Citation(s) in RCA: 364] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Vertebrates and invertebrates both have GABA (gamma-aminobutyric acid) as a major inhibitory neurotransmitter. GABAA receptors in vertebrates assemble as heteromultimers to form an integral chloride ion channel. These receptors are targets for drugs and pesticides and are also implicated in seizure-related diseases. Picrotoxinin (PTX) and cyclodiene insecticides are GABAA receptor antagonists which competitively displace each other from the same binding site. Insects and vertebrates showing resistance to cyclodienes also show cross-resistance to PTX. Previously, we used a field-isolated Drosophila mutant Rdl (Resistant to dieldrin) insensitive to PTX and cyclodienes to clone a putative GABA receptor. Here we report the functional expression and novel pharmacology of this GABA receptor and examine the functionality of a resistance-associated point mutation (alanine to serine) within the second membrane-spanning domain, the region thought to line the chloride ion channel pore. This substitution is found globally in Drosophila populations. This mutation not only identifies a single amino acid conferring high levels of resistance to the important GABA receptor antagonist PTX but also, by conferring resistance to cyclodienes, may account for over 60% of reported cases of insecticide resistance.
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Affiliation(s)
- R H Ffrench-Constant
- Department of Entomology, 237 Russell Laboratories, University of Wisconsin, Madison 53706
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Abstract
Receptors for 4-aminobutyric acid (GABA) have been identified in both central and peripheral nervous systems of several invertebrate phyla. To date, much of the information derived from physiological and biochemical studies on insect GABA receptors relates to GABA-gated chloride channels that show some similarities with vertebrate GABAA receptors. Like their vertebrate central nervous system (CNS) counterparts, agonist activation of such insect GABA receptors leads to a rapid, picrotoxin-sensitive increase in chloride ion conductance across the cell membrane. In insects, responses to GABA can be modulated by certain benzodiazepines and barbiturates. However, recent studies have detected a number of striking pharmacological differences between GABA-gated chloride channels of insects and vertebrates. Receptor binding, electrophysiological and 36Cl- flux assays have indicated that many insect receptors of this type are insensitive to the vertebrate GABAA antagonists bicuculline and pitrazepin. Benzodiazepine binding sites coupled to insect GABA receptors display a pharmacological profile distinct from that of corresponding sites in vertebrate CNS. Receptor binding studies have also demonstrated differences between convulsant binding sites of insect and vertebrate receptors. Insect GABA receptor molecules are important target sites for several chemically-distinct classes of insecticidally-active molecules. By characterizing these pharmacological properties in detail, it may prove possible to exploit differences between vertebrate and insect GABA receptors in the rational design of novel, more selective pest control agents. The recent application of the powerful techniques of molecular biology has revealed a diversity of vertebrate GABAA receptor subunits and their respective isoforms that can assemble in vivo to form a multiplicity of receptor subtypes. Molecular cloning of insect GABA receptor subunits will not only enhance our understanding of invertebrate neurotransmitter receptor diversity but will also permit the precise identification of the sites of action of pest control agents.
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Affiliation(s)
- N M Anthony
- AFRC Laboratory of Molecular Signalling, Department of Zoology, University of Cambridge, England
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Kern MD, Cowie RJ, Yeager M. Water Loss, Conductance, and Structure of Eggs of Pied Flycatchers during Egg Laying and Incubation. ACTA ACUST UNITED AC 1992. [DOI: 10.1086/physzool.65.6.30158274] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Prinzinger R, Hinninger C. (Endogenous?) diurnal rhythm in the energy metabolism of pigeon embryos. Naturwissenschaften 1992. [DOI: 10.1007/bf01175397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Since the discovery of vitamin A as a fat-soluble growth factor in the early part of the century, research into carotenoids and retinoids has attracted the attention of many scientists. These two groups of compounds are still being actively studied all over the world since many gaps in knowledge exist and new frontiers are being pursued. Recent developments in studies into the possible roles of carotenoids and retinoids beyond their classical functions in vision have created a great deal of excitement in the biomedical community. This review covers a wide range of topics pertaining to these two closely related compounds. Particular emphasis is given to the functions of these compounds and their roles in human nutrition. Various aspects of vitamin A deficiency and studies on carotenoids and retinoids in cancer development and prevention are reviewed in some detail.
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Affiliation(s)
- E S Tee
- Division of Human Nutrition, Institute for Medical Research, Kuala Lumpur, Malaysia
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Abstract
A GABA-operated Cl- channel that is bicuculline-insensitive is abundant in the nervous tissue of cockroach, in housefly head preparations and thorax/abdomen preparations, and in similar preparations from several insect species. Bicuculline-insensitive GABA-operated Cl- channels, which are rare in vertebrates, possess sites of action of benzodiazepines, steroids and insecticides that are pharmacologically-distinct from corresponding sites on vertebrate GABAA receptors. The pharmacological profile of the benzodiazepine-binding site linked to an insect CNS GABA-operated Cl- channel resembles more closely that of vertebrate peripheral benzodiazepine-binding sites. Six pregnane steroids and certain polychlorocycloalkane insecticides, which are active at t-butylbicyclophosphorothionate (TBPS)-binding sites, also differ in their effectiveness on vertebrate and insect GABA receptors. Radioligand binding and physiological studies indicate that in insects there may be subtypes of the GABA receptor. Molecular biology offers experimental approaches to understanding the basis of this diversity.
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Affiliation(s)
- D B Sattelle
- Department of Zoology, University of Cambridge, UK
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