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Brulez, Kaat. "Why are passerine eggshells spotted? : using calcium supplementation as a tool to explore eggshell pigmentation." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4619/.
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The eggshells of many avian species are spotted in appearance but the functional significance of such maculation is poorly understood. Protoporphyrin, responsible for brownish-red colouring on eggshells, is postulated to reinforce the structural integrity of eggshells under conditions when dietary calcium (Ca) is scarce. Within the context of this hypothesis, this thesis documents the use of Ca supplementation of two common British passerine species, blue (Cyanistes caeruleus) and great tits (Parus major), to explore the relationships between eggshell Ca and protoporphyrin content and visible pigment spotting. It further assesses the diversity of avian eggshell coloration using museum eggshells of 73 British passerine species. Despite low soil Ca availability, females were not necessarily Ca-limited but Ca-supplements may still influence eggshell traits and breeding behaviour, possibly by providing females with more time to invest in other activities. The importance of quantifying eggshell pigment concentrations directly, rather than using a proxy, is highlighted. Finally, this thesis shows that passerine eggshell pigment concentrations are highly phylogenetically conserved, thereby encouraging future studies testing key hypotheses to compare eggshell pigmentation of closely related species. This phylogenetic association may be essential to explain the functional significance of eggshell coloration of avian species.
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Hughes, R. J. "Influence of dietary electrolytes on blood acid-base balance in relation to formation of egg shells in the domestic hen." Title page, contents and summary only, 1989. http://web4.library.adelaide.edu.au/theses/09A/09ah894.pdf.
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Vonder, Haar Theresa Anne. "Engineering eggshells for carbon dioxide capture, hydrogen production, and as a collagen source." Connect to resource, 2007. http://hdl.handle.net/1811/25099.
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Thesis (Honors)--Ohio State University, 2007.Title from first page of PDF file. Document formatted into pages: contains 37 p.; also includes graphics. Includes bibliographical references (p. 35-37). Available online via Ohio State University's Knowledge Bank.
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Tharapoom, Kampanat. "Causes and consequences of variations in eggshells in the lesser black-backed gull." Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/5346/.
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Variations in egg size and egg composition between females of the same species, as well as among eggs in the same clutch, have been studied in many avian species. The eggshell serves crucial functions in avian reproduction such as protection of the embryo from mechanical damage and from the invasion of micro-organisms, source of calcium to the embryo, control of gas exchange with the environment and conservation of water. But little attention has been paid to variation in eggshell, especially within-clutch variation. This thesis focuses on variations in eggshell characteristics in relation to laying order in a single species, the lesser black-backed gull (Larus fuscus). In order to evaluate a proper method for measurement of eggshell characteristics, this thesis used more than one technique to measure shell thickness, shell porosity and shell coloration. For the measurement of shell porosity, two techniques for counting pores were validated for the first time in this thesis. This study found within-clutch variations in shell porosity, mammillary layer contact area and shell coloration but not in shell thickness. The last-laid egg had a larger mammillary layer contact area and often had paler shell colour and streaks on the shell. This study found some relationships between shell structures and shell coloration. A calcium-supplementation experiment was used to investigate whether the shell formation is limited by calcium-availability. This thesis found effect of calcium-limitation on shell thickness, but no effect on shell background colour.
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Cavallerano, Edward J. "Temporal diagenetic alternations in Adélie penguin eggshells throughout the late holocene of Antarctica /." Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/cavalleranoe/edwardcavallerano.pdf.
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Bryan, Teresa A. "Morphological and constituent analyses of American alligator (Alligator mississippiensis) eggshells from contaminated and reference lakes." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010640.
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Henry, Stacey Blalock. "“Walking on eggshells”: a qualitative study on the effects of trauma and deployment in military couples." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/9157.
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Doctor of PhilosophyDepartment of Family Studies and Human Services
Briana S. Goff
The purpose of this qualitative study was to gain an in-depth understanding of the systemic effects of trauma, particularly war-related traumatic stress as a result of military deployments to Iraq and Afghanistan, in a sample of recent war veterans and their spouses. With recent military deployments and redeployments of soldiers, empirical and clinical research is needed to eliminate further deterioration and retraumatization caused by personal and interpersonal traumatization that can lead to severe PTSD and other trauma-related symptoms. Much of the research on previous wars focused on the individual trauma survivor overlooking the impact on the couple and family system. This study focused on explaining the systemic effects of trauma as it specifically impacts couple relational systems. By employing qualitative analysis, six couples (12 participants) were selected from the original data set of 45 couples (90 participants). Participants completed questionnaires and separate individual standardized open-ended interviews about their traumatic experiences. The interviews were transcribed, coded, and analyzed producing four themes: positive impact of deployment on the couple’s relationship, the negative impact of deployment on the couple’s relationship, soldiers’ war-related trauma, and issues of secrecy. Two groups were identified (high trauma/high relational satisfaction group and high trauma/low relational satisfaction group), based on the quantitative measures that were completed by all participants. Participants reported both war deployment related and non-deployment related traumatic experiences. Many participants reported feeling as though they restarted their relationship upon returning home, while some described feeling closer to their spouse at redeployment. Participants reported having a common worry of if the soldiers would return home alive, soldiers’ missing many life events (i.e., child birth, etc.), and soldiers’ worry about the safety and health of their spouses. An interesting finding was that some couples with high levels of trauma can maintain high levels of relational satisfaction when they have knowledge and understanding of each other’s trauma history and have open, on-going communication, while some couples with high levels of trauma tend to have low relational satisfaction due to limited communication about their trauma history. Strengths and limitations of the study, research implications, and clinical implications were discussed.
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Savage, Joy Phoenix M. "Ambient Void." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/art_design_theses/83.
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Tshizanga, Ngoya. "A study of biodiesel production from waste vegetable oil using eggshell ash as a heterogeneous catalyst." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2153.
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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology.While biodiesel has the potential to resolve the energy crisis, its production is hampered by both feedstock and catalyst availability. The aim of this current study is to investigate the production of biodiesel from waste vegetable oil (WVO) as feedstock under heterogeneous catalysis, mediated by calcined eggshell ash. WVO, characterised by 9% free fatty acid (FFA) and 0.17wt% water content, was employed as feedstock in the biodiesel production via transesterification reaction. The composition of WVO was determined using Gas chromatography (GC) analysis. The eggshell was washed with distilled water to remove impurities, dried in an oven at 105°C, and then crushed into fine particle of 75μm, and finally, calcined in a muffle furnace at 800°C. The chemical properties of the catalyst were assessed as follows: 1) using X-ray diffraction (XRD) to determine the major component phase of the element; 2) using X-ray fluorescent (XRF) to determine the elemental composition of the eggshell ash; 3) using Brunauer Emmet Teller (BET) to define the structure, the surface area, pore volume and pore diameter of the eggshell ash; and 4) using SEM to show the morphology structure of the element. The XRD analysis performed on eggshell ash showed 86% CaO as a major component in the catalyst; the remaining 14% was composed of MgO, SiO2, SO3, P2O5, Na2O, Al2O3, K2O and Fe2O3, as obtained from XRF. The BET result of the catalyst prepared was characterised by large pore diameter (91.2 Å) and high surface area (30.7m2/g), allowing reactants to diffuse easily into the interior of the catalyst used
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Jelicic, Anna. "En hårdkokt historia : En studie av äggskalfynd från vikingatida gravkontext med särskilt fokus på Uppland och Gotland." Thesis, Uppsala universitet, Institutionen för arkeologi och antik historia, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324894.
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This thesis examines archaeological eggshell finds from cremation graves in the Swedish province of Uppland as well as inhumation graves from the island of Gotland. All graves are dated to the Viking Age, however, the chronology varies by the region, with the period´s ending placed around year 1050 AD in Uppland and around year 1150 AD at the island of Gotland. An attempt is made to create a list of all known cases of egg depositions in graves during the period of interest, and to subsequently analyse them all in order to get a better understanding of this practice. The comparative analysis of the artefact assemblages within the graves and grave constructions is undertaken in order to identify possible regularities in how and when the egg was used within the ritual sequence. Although notable regional variations and differences in Viking Age burial customs are known to exist between the two investigated regions, and artefacts deposited within the graves are adapted to regional conditions, it is possible, amongst other things, to observe similarities in the timing of egg deposition. By understanding the funeral as a rite of passage that signified the transition between the states of life and death, and with the final goal of achieving the distinction between the world of the living and the realm of deceased ancestors, it is possible to better comprehend the funeral rituals and their archaeological remains – in this case avian eggshells. By applying van Gennep's rites of passage tripartite structure, involving separation, liminality, and incorporation, it is concluded that eggs, as we see them in the archaeological material presented in this study, are used in the last stage of this model. This is the part of the process where the main goal is reintegration of those who participated in ritual into a new social order. It is thus proposed here that eggs might be seen as hierophanies: profane, everyday objects that have manifested into something sacred and who are clearly understood as such to those involved in burial but not necessary to outsiders: as symbols for fertility, regeneration, rebirth and transformation.
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Fecheyr, Lippens Daphne. "Implementing Biomimicry Thinking from fundamental R&D to creating nature-aligned organizations." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1506510439362348.
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Saki, Ali Asghar. "Effects of dietary calcium, phytoestrogen rich diets and estrogen on intestinal calcium transport proteins, egg and eggshell quality in maturing layer hens." Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09ANP/09anps158.pdf.
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Thesis (Ph. D.)--University of Adelaide, Dept. of Animal Science, 1998.Corrigenda inserted behind title page. Copies of author's previously published articles inserted. Includes bibliographical references (leaves 193-210).
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Garcia, Sellés Albert. "Oological Record of Dinosaurs in South-Central Pyrenees (SW Europe): Parataxonomy, diversity and biostratigraphical implications." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/84108.
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Southern Pyrenees has provided an abundant fossil record of dinosaur eggs and eggshells. Historically, the oofamily Megaloolithidae has shown its predominance over any other group of fossil eggs in this region. In addition, this oofamily is world-wide distributed being represented by, at least, four oogenus and 20 oospeices. Considering that the eggshell is a high stable structure, this number of Megaloolithus‘s oospecies is too high for such a relatively short time-interval (Campanian to Maastrichtian; less than 7 My). The structural characters used to define these oospecies are critically revised. As a consequence, three structural groups have been identified, and only ten oospecies have been considered valid. Four of those oospecies have been recognized in Southern Pyrenees: M. aureliensis, M. sirugei, M. mamillare and M. baghensis.
The oogenus Cairanoolithus, historically included in Megaloolithidae oofamily, is reevaluated. All evidences suggest that this type of fossil egg is, definitively, different from any other Megaloolithus. Consequently, a new oofamily is erected (Cairanoolithidae oofam. nov), which emphasizes the singularity of cairanoolithid eggs. Phylogenetical analysis also suggests that the eggs of Cairanoolithidae oofam. nov. could be laid by ornithischian dinosaurs.
New oological material is described here, including the first spheroolithid oospecies (Spheroolithus oosp. nov.) from the Upper Cretaceous of Europe. Several oospecies of Prismatoolithus (Prismatoolithus oosp. nov, Prismatoolithus cf. levis, Prismatoolithus oosp. indet.) and few eggshells of ratite-morphotype (cf. Ageroolithus fontllonguensis) have been identified. In addition, the great number of specimens attributed to Pseudogeckoolithus oogenus allows re-describing and re-assigning this ootaxon to Mesozoic lizards.
The space-temporal variation of the oological diversity in the Southern Pyrenees could be a consequence of environmental changes during the end-Cretaceous or even due to preferences in the nesting-site of each group of dinosaurs.
Finally, biostratigraphical studies based on the successions of megaloolithid oospecies have been performed in Coll de Nargó and Àger-Tremp basins, and the European Megaloolithus succession has been updated. As a result, three oozonones have been described: M. aureliensis + Cairanoolithus oozone dates the Late Campanian, M. siruguei oozone the Early Maastrichtian and M. mamillare + M. baghensis oozone the Late Maastrichtian.
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Jimenez, O. E. Rubilar. "Bioprocessing of chicken eggshell waste." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419424.
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Sparks, N. H. C. "The hen's eggshell : a resistance network." Thesis, University of Bath, 1985. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354730.
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The formation and the fine structure of the components (cuticle, porous calcitic shell, shell membranes and limiting membrane) of the integument of the hen's egg were studied in detail with Scanning Electron Microscopy or, when appropriate, Transmission Electron Microscopy, in order to build up a detailed picture of the physical, antimicrobial systems of the egg pre- and post-oviposition. This phase of the study revealed that (i) the limiting membrane is present on the egg in the magnum, (ii) the interstitial spaces of the shell membranes in the oviduct are filled with amorphous material which probably condenses to form the mantle on the individual fibres of the membranes and (iii) the cuticle at oviposition is immature and mechanically weak. The immature cuticle is an ineffective barrier to bacterial penetration for a few minutes post-oviposition. When the components of the integument were considered as resistances in series, the mature cuticle - especially that on brown eggs - was shown to be the major barrier to the movement of water in the liquid but not the vapour state. Consequently this structure plays an important role in protecting the egg contents from infection. Work needs to be done in order to overcome this resistance - differences in partial pressure caused by immersing warm eggs in a cold solution overcame the cuticle's resistance. The efficacy of this method was enhanced by reducing the surface tension or "degassing" the water. Of the many methods used to assess cuticle quality, staining was the only one that would appear to be of any use at the moment in a breeding programme that sought improvements in the quality and hence effectiveness of the cuticle as a barrier to infection. The porosity of the shell, as measured by GH2O, was not associated with water uptake by eggs. Nevertheless the pore contributed to the waterproofing, and hence antimicrobial defence of the egg, by imposing such a resistance to water movement that the osmotic potential of the albumen to pull water across the shell membranes was negated. The shell membranes proved to be ineffective barriers to microbial movement. The contribution of the limiting membrane to the egg's defence could not be assessed with the techniques used in this study. The environment within the shell membranes was selective for Gram-negative bacteria. Indeed the membranes appeared to offer a haven for microorganisms that had passed across the shell, especially in infected eggs held under conditions recommended for hatching eggs before transfer to incubation temperature. In practice viable organisms persisted in these structures whereas contaminants of the underlying albumen died out especially with incubation temperatures approaching the body temperature of the hen. Heavy microbial challenges (>106/egg) to the shell membranes resulted in heavy contamination of the albumen within two days of infection. It was deduced that contaminants of the albumen failed to multiply unless they made contact with the yolk. The above observations were discussed in the context of practices that should be considered by hatchery managers who seek to interrupt the transfer of Salmonella from the breeding to the rearing flock by egg treatment. The identification of the immature cuticle state directs attention to the management and hygiene of nest boxes and the primary role of the cuticle in the eggs antimicrobial defence. It suggests that breeding programmes ought to be concerned with the quality of the cuticle throughout the laying cycle. The influence of temperature on the behaviour of contaminants in the shell membranes suggest also that treatment of eggs with germicides to control Salmonella transmission needs to be done.
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Bain, Maureen Margaret. "Eggshell strength : a mechanical/ultrastructural evaluation." Thesis, University of Glasgow, 1990. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606855.
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Cordeiro, Cristianne. "Eggshell Membrane Proteins provide Innate Immune Protection." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33389.
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The microbiological safety of avian eggs is a major concern for the poultry industry and for consumers due to the potential for severe impacts on public health. Innate immune defense is formed by proteins with antimicrobial and immune-modulatory activities and ensures the protection of the chick embryo against pathogens. The objective of this project was to identify the chicken eggshell membrane (ESM) proteins that play a role in these innate immune defense mechanisms.
We hypothesized that ESM Ovocalyxin-36 (OCX-36) is a pattern recognition protein, and characterized purified ESM OCX-36. OCX-36 has antimicrobial activity against S. aureus and binds E. coli lipopolysaccharide (LPS) and S. aureus lipoteichoic acid (LTA). We additionally investigated the OCX-36 nonsynonymous single nucleotide polymorphisms (SNPs) at cDNA position 211. The corresponding isoforms (proline-71 or serine-71) were purified from eggs collected from genotyped homozygous hens. A significant difference between Pro-71 and Ser-71 OCX-36s for S. aureus LTA binding activity was observed. From these experiments, we confirmed the hypothesis that OCX-36 is a pattern recognition molecule. We also found that OCX-36 has anti-endotoxin properties and is a macrophage immunostimulator to produce NO and TNF-α. Digested OCX-36 down-regulated the expression of genes involved in LPS signaling and inflammatory responses. Moreover, OCX-36-derived peptides inhibited the production of LPS-induced pro-inflammatory mediators associated with endotoxemia in vivo.
Quantitative proteomics analysis of ESMs was performed to evaluate changes in ESM protein abundance during chick embryonic development. Bioinformatics analysis revealed enrichment of proteins associated with antimicrobial and immune protection, vascularization, calcium mobilization and lipid transport, which are vital for chick embryonic development. In unfertilized eggs, protease inhibitors and antimicrobial proteins were enriched.
In summary, the ESMs are enriched in proteins with antimicrobial, antioxidant and immune-modulatory properties, which aid in the development of the chick embryo and protect the embryo and unfertilized egg against pathogen invasion.
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Stewart, John. "Making eggshell visible in the archaeological record." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/5292/.
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Despite its presence in many types of deposit, eggshell has long been a neglected archaeological resource. The difficulty of recovering the material, combined with analytical constraints on subsequent taxonomic identification, has led to systematic underuse. This thesis will begin to address this shortcoming by pursuing two main lines of research. First, a novel identification technique based on ZooMS (zooarchaeology by mass spectrometry) and peptide mass fingerprinting is developed for eggshell. The new technique is then applied to archaeological eggshell assemblages from Anglo-Scandinavian York and Norse-era sites in the northern and western isles of Scotland. This provides new insights into egg use in these locations during this period, and raises a range of new questions regarding the use of domestic and wild resources. Second, an investigation into patterns of diagenesis in the eggshell proteins which form the basis of the technique is conducted. The principal aims of this analysis are to explore the prevalent diagenetic processes affecting eggshell proteins and amino acids, and thus to test whether it is possible to produce an estimate of the expected temporal span of the technique based on high-temperature diagenesis, and to establish the potential usefulness of the material for IcPD (intra-crystalline protein diagenesis) dating. The main outcomes of this study are (i) the development and successful application of a new taxonomic identification technique for archaeological eggshell; (ii) enhanced understanding of egg use during the Norse era in Scotland and Anglo-Scandinavian York; (iii) the observation that high-temperature diagenesis cannot be used to accurately predict peptide survival at archaeological deposition temperatures; and (iv) that avian eggshell is not a viable substrate for absolute dating using IcPD (although it may still prove useful for relative dating).
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Onelli, Olimpia Domitilla. "Complex photonic structures in nature : from order to disorder." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273768.
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Structural colours arise from the interaction of visible light with nano-structured materials. The occurrence of such structures in nature has been known for over a century, but it is only in the last few decades that the study of natural photonic structures has fully matured due to the advances in imagining techniques and computational modelling. Even though a plethora of different colour-producing architectures in a variety of species has been investigated, a few significant questions are still open: how do these structures develop in living organisms? Does disorder play a functional role in biological photonics? If so, is it possible to say that the optical response of natural disordered photonics has been optimised under evolutionary pressure? And, finally, can we exploit the well-adapted photonic design principles that we observe in Nature to fabricate functional materials with optimised scattering response? In my thesis I try to answer the questions above: I microscopically investigate $\textit{in vivo}$ the growth of a cuticular multilayer, one of the most common colour-producing strategies in nature, in the green beetles $\textit{Gastrophysa viridula}$ showing how the interplay between different materials varies during the various life stages of the beetles; I further investigate two types of disordered photonic structures and their biological role, the random array of spherical air inclusions in the eggshells of the honeyguide $\textit{Prodotiscus regulus}$, a species under unique evolutionary pressure to produce blue eggs, and the anisotropic chitinous network of fibres in the white beetle $\textit{Cyphochilus}$, the whitest low-refractive index material; finally, inspired by these natural designs, I fabricate and study light transport in biocompatible highly-scattering materials.
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Du, Jingwen. "Chicken Eggshell Membrane and Cuticle: Insight from Bioinformatics and Proteomics." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23631.
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The chicken eggshell possesses physical and chemical barriers to protect the embryo from pathogens. The avian eggshell cuticle is the outmost layer of the eggshell whose protein constituents remain largely unknown. Since eggs with incomplete or absent cuticle are more susceptible to bacterial contamination, we hypothesize that cuticle protein components play an important role in microbial resistance. In our study, at least 47 proteins were identified by LC/MS/MS in the non-calcified cuticle layer. Similar to Kunitz-like protease inhibitor (also annotated as ovocalyxin-25, OCX-25) and ovocalyxin-32 (OCX-32) were two of most abundant proteins of the cuticle proteins. Some proteins that have antimicrobial activity were also detected in the proteomic results, such as lysozyme C, ovotransferrin, ovocalyxin-32, cystatin, ovoinhibitor. This study represents the first comprehensive report of the cuticle proteome. Since the sequence similarity of the kunitz motif in OCX-25 is similar to that of BPTI, it is predicted that it will have the same trypsin inhibitory and antimicrobial activity against Gram-positive and/or Gram-negative bacteria. In order to test the antimicrobial property and trypsin inhibitor activity of OCX-25, cuticle proteins were extracted by 1N HCl. Antimicrobial activity was monitored using the Bioscreen C instrument; and antimicrobial activity was identified primarily against Staphylococcus aureus. Trypsin inhibitor activity was studied by using a specific trypsin assay, and the assay indicated that the cuticle proteins could inhibit the reaction of trypsin and substrate. Therefore, the current research has provided some insight into the antimicrobial and enzymatic aspects of the cuticle proteins, and its function for egg protection.
Eggshell membranes are another important component of the chicken eggshell.Due to its insoluble and stable properties, there are still many questions regarding formation and constituents of the eggshell membranes. The purpose of our study was to identify eggshell membrane proteins, particularly these responsible for its structural features, by examining the transcriptome of the white isthmus during its formation. Bioinformatics tools were applied to analyze the differentially expressed genes as well as their encoded proteins. Some interesting proteins were encoded by the over-expressed genes in the white isthmus during the formation of eggshell membranes, such as Collagen X, and similar to spore coat protein SP75. These proteins may have potential applications. Our study provides a detailed description of the chicken white isthmus transcriptome during formation of the eggshell membranes; it could lead to develop the strategies to improve food safety of the table egg.
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Oskam, Charlotte. "Ancient DNA & stable isotope profiling of fossil eggshell." Thesis, Oskam, Charlotte (2012) Ancient DNA & stable isotope profiling of fossil eggshell. PhD thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/12744/.
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Eggshell is frequently encountered within palaeontological and archaeological deposits and due to various chemical and physical properties, it is highly valued as a substrate for geochronology, palaeodietary and palaeoecological applications. Despite the wellrecognised preservation of biomolecules in fossil eggshell, the substrate had never been evaluated for ancient DNA (aDNA) preservation. Herein, this thesis describes the first exploration involving the recovery and characterisation of aDNA from fossil eggshell. The primary aim of this thesis research is to explore eggshell aDNA and how genetic data, when combined with stable isotope profiles, provides new insights into hunting practices, zooarchaeology, palaeodiets, palaeobiology and extinction processes.
The visualisation of fluorescently-stained DNA in fossil eggshell by confocal microscopy revealed that genetic material was present in the eggshell of the extinct New Zealand moa (Aves: Dinornithiformes) and Madagascan elephant bird (Aves: Aepyornithiformes). The immediate task was to determine how to go about characterising the aDNA encapsulated in this previously unrecognised substrate. Quantitative PCR assays were employed to thoroughly evaluate different methods to maximise the recovery and amplification of aDNA from powdered eggshell. This study resulted in the successful characterisation of both mitochondrial and nuclear DNA isolated from 19,000 year-old emu eggshell and the first ever DNA sequence from the elephant bird, Aepyornis. All data pointed toward fossil eggshell as a reliable source of relatively pure aDNA. This work culminated in a formal description of the methodology that should be employed to maximise recovery of aDNA from eggshell.
Next, this thesis investigates whether eggshell aDNA could be applied to ‘first-contact’ archaeological sites in New Zealand, to gain new insights into the Moa-hunter period of prehistory. The abundance of moa eggshell within the ‘first-contact’ Polynesian archaeological sites is well recognised from previous excavations. With nine species of moa contained within the New Zealand archipelago however, the scientific value of these remains has been limited by the lack of definitive species assignments. Genetic species assignments of moa eggshell combined with morphological identification of bone (literature and museum catalogued specimens) has enabled the most comprehensive audit of zooarchaeology assemblages from several significant 13th-15th century AD deposits. In total, mitochondrial DNA (mtDNA) was amplified from 251 of 323 (78 %) eggshell fragments and 22 of 27 (88 %) bone samples, and the analyses revealed the presence of four moa species: Anomalopteryx didiformis; Dinornis robustus; Emeus crassus; and Euryapteryx curtus. The mtDNA, together with highly polymorphic microsatellite markers, were used in combination to individualise eggshell fragments. These data revealed over 50 individual eggs from Wairau Bar – a number that likely represents a considerable proportion of the total reproductive output of moa in the area. This emphasises that human predation of all life stages of moa was intense. In addition, an excess of male bones at the Wairau Bar site (determined by molecular sexing) suggests that males might have been preferential targets, perhaps while incubating eggs.
Lastly, moa eggshell genetics and stable isotope profiles were combined to examine the palaeodiets, palaeobiology, palaeoecology and the human mediated extinction of the moa. Organic (δ13Corg and δ15N) and carbonate (δ13Ccarb and δ18O) stable isotope profiles were analysed from 247 genetically identified eggshell fragments. The combination of ancient DNA and stable isotope profiles revealed moa consumed a diet consisting exclusively of C3 vegetation and occupied the varied landscape that surrounded the archaeological deposits. Given that moa were foraging in such diverse landscapes suggests that the first colonisers hunted these moa away from the homogenous landscapes immediately surrounding these archaeological sites and thus engaged in ‘central point foraging’. Discriminant functional analyses indicate moa eggshells can be assigned with good precision to their parent species based purely on their stable isotope profiles.
In conclusion, this thesis research has revealed a ‘new’ aDNA substrate that has a number of useful applications in archaeology, palaeogenomics and palaeoecology. The research on New Zealand moa eggshell demonstrated, first-hand, how this substrate can provide valuable insights into the biology, ecology and extinction of a megafaunal species. It is hoped the research will have a lasting influence on eggshell discovered across the globe.
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Lammie, Donna. "An investigation of the nanostructural features of avian eggshell." Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/30959/.
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The avian eggshell is a highly ordered bioceramic with both inorganic and organic constituents. The eggshell takes approximately 18 hours to form in the shell gland region of the hen's oviduct, a process which is repeated every 24 hours in modern hybrid laying hens, which are capable of laying in excess of 300 eggs per annum. Although the formation of the eggshell is rapid, it still results in a structure that is highly organised and which displays unique functional properties that depend on the interplay between its mineral and protein phases. The interactions between the inorganic and organic components during the formation of the eggshell however are poorly understood but it is likely that they occur at the nanometer level. Thus, it is hypothesised that structural variation at the nanostructural level will impinge on the overall structural integrity and mechanical performance of the eggshell. In this thesis. X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and microfocus small angle X-ray scattering (?SAXS) were applied to investigate the nanostructure of the eggshell. A description of these different techniques is given in Chapter 2 along with theoretical considerations as to how the resulting data presented in subsequent chapters was analysed. In Chapter 3, thin sections of normal and abnormal eggshells, where the layers were structurally intact, were analysed using ?SAXS. The results of this experiment suggest that there are nanostructural features within the different layers of normal eggshells, especially in the mammillary layer. The size dimensions of these nanopores/nanovoids were subsequently estimated to be between 3 - 5 nm in both visually normal and abnormal eggshells. However, despite being of similar size, the distribution of these nanopores or voids was found to be disrupted in the abnormal eggshell samples. In Chapter 4, XRD and SAXS were used to analyse powdered eggshell samples which represented different stages of gestation. In this case, the diffraction and scattering data produced were used to calculate an average size measurement of the structural features within bulk eggshell samples. The X-ray diffraction data indicated that the crystallite sizes were large, between 54-232 nm. However, size dimensions of approximately 5.7 - 7.2 nm were observed from the analysis of the SAXS data confirming the hypothesis that SAXS was measuring nanovoids within the crystallites arising from the presence of embedded protein. A further study using SAXS to compare the nanostructural features of eggshells of varying mechanical strengths is presented in Chapter 5. Here, powdered eggshells from young and aged hens were compared and found to contain an average nanovoid size value of approximately 5.9 nm and 5.8 nm, respectively. These size dimensions were confirmed by a parallel study in which mercury intrusion porosimetry was used to investigate pore size distribution. It was concluded that the average size of nanovoids is comparable in eggs of different mechanical strength. Chapter 6 describes the results of an investigation in which SAXS was used to monitor the nucleation events which take place when calcium carbonate is grown in vitro with and without the presence of eggshell proteins. The results of this study although preliminary suggest that the initial nucleation event is extremely rapid and provides a unique insight into the size of the calcium carbonate crystals which initially form. The main conclusions from this thesis are summarised in Chapter 7, in relation to the effect that changes in eggshell nanostructure could have on the overall structure and function of this complex biomineralised structure. Potential further studies are also discussed.
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Rose-Martel, Megan. "Innate Mechanisms of Antimicrobial Defense Associated with the Avian Eggshell." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32299.
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During the course of evolution, the avian egg has developed multiple physical and chemical barriers in order to resist microbial challenges. These barriers are essential for the successful reproduction of avian species as well as to maintain safe and nutritious food for human consumption of the table egg. The calcified eggshell is a biomineralized barrier with an integrated organic matrix containing antimicrobial proteins, a hallmark of sophisticated biological structures. Calcium carbonate is deposited onto the outer shell membranes to form the calcified mammillary, palisade and vertical crystal layers; the final layer to be deposited is the outer eggshell cuticle. In this thesis, mass spectrometry-based technology was used to investigate the proteome of the outer cuticle, the mammillary cones and the shell membranes in order to gain insight into biomineralization and antimicrobial functions of the avian eggshell. Proteomics analysis of the eggshell cuticle revealed multiple antimicrobial proteins, supporting the hypothesis that the outermost cuticle layer is the first barrier against invading pathogens. The two most abundant cuticle proteins identified are similar to Kunitz-like protease inhibitor (ovocalyxin-25) and ovocalyxin-32. Multiple antimicrobial proteins were also revealed to be associated with the shell membrane fibres. Among the most abundant proteins were lysozyme C, avian β-defensin-11, ovotransferrin, ovocalyxin-36 and gallin. The biomineralized shell is also an important physical barrier against invading pathogens. Proteomics analysis of the mammillary cones, the initiation sites for shell calcification, revealed several candidate proteins involved in calcitic biomineralization. Promising candidates include nucleobindin-2 and SPARC, two calcium binding proteins previously shown to modulate mineralization. In-depth analysis of the comprehensive proteomes generated by this study revealed the presence of histones in the shell membranes, shell and cuticle compartments. Histones are cationic antimicrobial peptides, which are key molecules of the innate immune defense system of many species. This thesis reports the minimal inhibitory concentrations and minimal bactericidal concentrations of histones extracted from avian erythrocytes against Gram-positive, Gram-negative and antibiotic-resistant bacteria. Results suggest that the underlying antimicrobial mechanism is based on the interaction between histones and lipopolysaccharides / lipoteichoic acids, which are negatively charged components of bacterial cell membranes. Histones also inhibit the growth of Gram-positive biofilms; the minimal biofilm eradication concentrations were determined for S. aureus and methicillin-resistant S. aureus (MRSA). Sensitive proteomics analyses have provided great insight into the protein constituents of the eggshell matrix, with two primary roles in the innate immune defense of the egg: regulation of calcitic biomineralization and antimicrobial protection. Further research on these proteins and their functions can provide a new focus for selective breeding programs looking to enhance the egg’s natural defenses, or provide inspiration for alternatives to conventional antibiotics, such as the histones.
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Peluso, Enzo. "Eggshell catalyst for hydrocarbon synthesis, kinetic modeling and reactor performance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0033/MQ30754.pdf.
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Hussain, Abid. "Dielectric properties and microwave assisted separation of eggshell and membrane." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=67033.
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Eggshell and membranes which are largely disposed of as waste are a reserve of many bioactive compounds with high economic and monetary value which can be extracted by the efficient separation of eggshell and membrane. Hence, this study concentrates on finding a suitable method for separating the eggshell from membrane. First, the effect of microwave treatment on separation of eggshell and membrane was investigated. The response of a material to electromagnetic radiation depends upon its dielectric properties; therefore, the study of the dielectric properties of eggshell and membrane was carried out in the range of 200 MHz to 20 GHz and in the temperature range of 25 0C to 100 0C. Also, the possibility of using this technique for detection of protein denaturation in egg membrane and shell was investigated. In the second part of the study, the effectiveness of microwave treatment on separation of eggshell and membrane was analyzed in terms of reduction in total energy required to separate the eggshell and membrane and was termed as bond energy. For all microwave treatments, three factors with three levels each were considered. Microwave treatment of eggs significantly reduced the bond energy between eggshell and membrane. A Model for calculating the bond energy between the eggshell and membrane for all microwave treatments was established.Généralement rejetées, les coquilles et membranes d'œuf représentent une importante réserve de composés bioactifs ayant une grande valeur économique et pécuniare, cette étude se concentre donc sur le problème de trower une méthode appropriée pour séparer la coquille de la membrane. Premièrement, notre étude évalua l'effet d'un traitement aux micro-ondes sur l'aise de séparation de la membrane de la coquille. Comme la réaction d'un matériel aux rayonnements électromagnétiques dépend de ses propriétés diélectriques, les propriétés diélectriques de coquilles et membranes furent donc indépendamment évaluées dans une gamme de frequencies de 200 MHz à 20GHz, en combinaison avec des températures variant de 25°C à 100°C. De plus, la possibilité d'utiliser cette technique pour détecter la dénaturation des protéines membranaires fut évaluée. En second lieu, l'efficacité du traitement aux micro-ondes à faciliter la séparation de la membrane de la coquille fut éprouvée en fonction de la réduction en énergie necessaire à cette séparation, soit l'énergie de liaison. Pour l'ensemble des traitements aux micro-ondes, trois facteurs à trois niveaux chacun furent évalués. Le traitement aux micro-ondes réduisit de façon significative l'énergie de liaison entre la membrane et la coquille. Un modèle fut développé permettant le calcul de l'énergie de liaison entre membrane et coquille, sous les divers traitements aux micro-ondes et selon les différents facteurs.
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Membreno, Nelson Armando. "Effects of eggshell removal on embryonic skeletal development in the American alligator (Alligator mississippiensis)." CSUSB ScholarWorks, 2017. https://scholarworks.lib.csusb.edu/etd/529.
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The eggshell of reptiles is essential for not only protecting the embryo, but can also serve as source of calcium for embryonic skeletal development. Whereas embryonic lepidosaurs and chelonians rely on their yolk sac for calcium during development, embryonic archosaurs mobilise eggshell calcium supply to both the embryo and the yolk sac. By the time archosaurs hatch, their residual yolk sacs have a calcium content equal or greater than at time of oviposition, which is used to support post-hatching growth. To date, no study has looked into how removal of the calcareous eggshell affects embryonic development in archosaurs. I tested how the removal of the calcareous eggshell affects embryonic and hatchling growth and biomechanic function of the skeleton in embryos and hatchlings of the American alligator (Alligator mississippiensis). Experimental eggs had their eggshell manually peeled, while control eggs were sham handled but otherwise not altered. Sampling of eggs occurred on a weekly basis until the end of incubation. Embryos, yolk sacs, and eggshells were removed and analyzed for morphological, histological and biomechanical parameters. Results show that at the time of eggshell peeling yolk sac calcium reserves were sufficient for experimental embryos to develop, but animals hatched in diminutive state. Serial clearing and staining of embryos revealed that onset of bone mineralization was similar for both treatment groups. Growth trajectory of experimental hatchlings parallelled that of control animals, without compensatory growth. Experimental hatchlings were observed to have flexible lower jaws and produced a weaker bite force than control hatchlings. Cross-sections of the mandible and femoral mid-diaphysis had a significantly reduced cross-sectional area in experimental hatchlings. I conclude that loss of the calcareous eggshell during incubation leads to severe constraint on growth and biomechanics of the alligator skeleton.
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Sacia, Eric Ryan. "Synthesis and regeneration of enhanced eggshell sorbents for clean coal applications." Connect to resource, 2009. http://hdl.handle.net/1811/36984.
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Frye, Hannah. "Eggshell calcium regulates calcium transport protein expression in an oviparous snake." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/honors/237.
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One hypothesis explaining the numerous independent evolutionary transitions from oviparity to viviparity among squamates (snakes and lizards) proposed that squamate embryonic development is independent of eggshell calcium. Recent research showed at least 25% of the calcium in hatchling oviparous squamates is extracted from the shell. Though not a direct test, these results are inconsistent with the hypothesis. To directly test the hypothesis, we removed eggshell calcium (through peeling) early in development of Pantherophis guttatus (corn snake) eggs. Survivorship to hatching did not differ between peeled and intact eggs. Yet hatchlings from peeled eggs were shorter (273.6 ± 3.4 vs. 261.0 ± 3.7 mm, p=0.0028, n=16), lighter (6.36 ±0.22 vs. 5.75 ± 0.23 g, p=0.0158, n=16), and had reduced calcium (40.8 ± 1.7 vs. 30.5 ± 1.8 mg, p
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Sofee, Sofidar. "Äggskal,avfall eller resurs? : En materialdriven designprocess." Thesis, Högskolan i Gävle, Avdelningen för industriell ekonomi, industridesign och maskinteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-36411.
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Egg consumption in Sweden is very high, which means a lot of egg shells are thrown out. For example the average swede consumes about 350 eggs every year. In this thesis I have investigated how eggshells can be applied in new areas as a resource, and I want to inspire the reader and encourage them to rethink what is called waste. Is it really waste or a possible resource? The work began with literature search, interviews and a survey to understand people's views on eggshells. I have concluded that not a lot of people know what eggshells are made of, and what they are used for. In a literature search I came across many scientific articles on eggshells. According to King’ori (2011) eggshells are used as fertilizers, used in medicine, cosmetic surgery, and dental care, calcium supplements, in the food industry and in crafts. When eggshell is thrown as food waste it creates problems in recycling stations, the eggshell is like sediment and lies at the bottom of tanks and pipes. The recycling staff have to perform additional work when cleaning tanks and pipes as eggshells are like sediment and lay at the bottom. The staff have to manually shoot out eggshells with many other useful materials that could have been digested and become biogas. This is an exploratory thesis where I investigate the material eggshell through a material-driven design process to find new sustainable uses. I follow the material-driven design process method by Karana et al.( 2015) plus my own added steps during the process. Material driven design process is a process where designers use a material to find the attributes of the material. These are then presented in new contexts or already existing contexts, this means that the material on the existing product can be replaced. This differs from traditional design, where the material is chosen based on wanted attributes. This report will give you an understanding of the material-driven design process-method and how I have carried out a material-driven design process, to develop different material properties of eggshells. The report ends with a concluding discussion and presents new eggshell-based materials that I have produced in the form of a demonstrator. It is a book which has two different materials, a hard material and a paper material which are combined and put together with a steel thread. I will also share my knowledge about eggshells and what potential it has in the future.
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Crisp, Molly Katherine. "Amino acid racemization dating : method development using African ostrich (Struthio camelus) eggshell." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/4770/.
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Ostrich eggshell (OES) is ubiquitous in archaeological sites in Africa and is a favoured substrate for amino acid racemisation (AAR) geochronology, yielding consistent results and thought to approximate a closed system with respect to protein diagenesis. It was found that the intra-crystalline fraction in OES can be isolated by oxidative pre-treatment and that these amino acids are resistant to leaching and unaffected by changes in the environmental pH (between pH 5 and 9). The intra-crystalline fraction in OES therefore effectively operates as a closed system with respect to protein diagenesis. This intra-crystalline fraction is likely to be a superior sample compared to whole-shell samples, removing uncertainty introduced through variable leaching rates, different ground water conditions and potentially exogenous contamination. Kinetic studies on modern OES indicate that high temperature data should be treated with caution when used to extrapolate kinetic parameters at low temperatures. This reinforces previous work that indicates the underlying mechanisms driving protein diagenesis need to be better understood in order to estimate accurate kinetic parameters, as the pathways of diagenesis are different at high and low temperatures. Nonetheless, hydrolysis and racemization have been shown to follow predictable patterns of diagenesis, and are therefore useful for the application of relative dating in AAR geochronology. Therefore, a chronological framework for southern South Africa was built by AAR analysis of a suite of OES samples, with calibration from independent dating methods (optically stimulated luminescence and radiocarbon), up to 151 ka. Through extensive artificial heating studies on modern OES samples, a checklist of 6 markers has been developed to identify sub-fossil samples that have been exposed to high temperatures. Exclusion of these heated samples from AAR age models significantly increases the age resolution. Analysis of several amino acid chiral pairs allowed age resolution over the full time range studied (~0.3 ka – 151 ka), allowing differentiation of MIS 1, 2, 3/4, 5 and 6. It has been shown that OES AAR offers a useful additional relative dating technique for archaeological and palaeontological sites from the same regions as Pinnacle Point and Elands Bay Cave, up to at least 151 ka (MIS 6). Furthermore, as 151 ka samples have racemization for some amino acids (e.g. isoleucine) only half way to equilibrium, there is considerable potential for OES AAR geochronology in South Africa beyond 151 ka. In addition, a preliminary study has demonstrated the potential of mass spectrometry in helping to unravel the complex nature of protein diagenesis within bio-minerals. Peptides from ~71 ka sub-fossil samples were successfully extracted and sequenced. It is believed this is the first time this has been done for eggshell samples of this age. This kind of study offers interesting insights into the patterns of protein preservation and degradation, with implications for understanding the role and function of proteins in the bio-minerals. Finally, a new ultra-high pressure liquid chromatography (UHPLC) method for the chiral separation of amino acids has been developed, with an analysis time (60 min including flush time) approximately half that of the previous HPLC method, allowing a higher throughput of samples. This new method also separates additional analytes, previously unstudied in AAR geochronology, which may offer further insight into protein diagenesis within bio-minerals.
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Higley, Stephen. "Eggshell as a renewable and sustainable resource for energy storage in supercapacitors." Thesis, Higley, Stephen (2019) Eggshell as a renewable and sustainable resource for energy storage in supercapacitors. Honours thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/44798/.
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It is thought that eggshell biowaste from the cosmetic and pharmaceutical industry could be used as a precursor for energy storage as a suitable waste management plan and increase the sustainability of said industry rather than ending up in landfill. When comparing the morphology of synthetic calcium carbonate with eggshell it can be theorised that eggshell or one or more of the calcium carbonate polymorphs namely calcite, aragonite and vaterite could be used as an electrode for supercapacitors. By applying the morphological knowledge obtained through the literature survey and by physically and electrochemically characterising eggshell in three distinctive crystalline states of the calcite, will allow this thesis to confirm eggshell as a sustainable and renewable resource for electrode material for energy storage in supercapacitors.
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Stein, Laura Renee. "EVOLUTION OF EGGSHELL ARCHITECTURE ACCOMPANYING RAPID RANGE EXPANSION IN A PASSERINE BIRD." Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/192996.
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Darnell-Middleton, Sally Louise. "The relationship between eggshell quality and bone biology in the laying hen." Thesis, University of Glasgow, 1999. http://theses.gla.ac.uk/30935/.
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(1). In this thesis the relationship between eggshell quality and bone biology was examined over the laying life of two strains of hen; a highly selected commercial line and the relatively unselected J.Line. (2). The efficiency of using osteocalcin as a marker of osteoid formation, in collaboration with established markers of bone mineralisation and bone resorption, during eggshell calcification was ratified. (3). It was established that magnesium is actively removed from bone hydroxyapatite during resorption and transported to the shell gland pouch for incorporation into the palisade layer of the eggshell. (4). A relationship was demonstrated between hatched eggshell quality and the bone biology of newly hatched chicks. (5). The association between high egg output and poor bone structure was evident in the commercial laying strain hen. No such deficit in skeletal quality occurred in the relatively unselected J.Line. (6). The commercial line demonstrated a significantly higher rate of bone remodelling at late lay concomitant with osteoporosis. (7). The unselected J.Line demonstrated significantly higher rates of bone remodelling throughout lay. It was hypothesised that this was due to a greater propensity for bone upkeep during the inter-egg interval. (8). The provision of a prelay diet influenced neither bone volume nor mineral composition at the beginning of lay. (9). The feeding of a prelay diet led to a longer period of sustained high production and an earlier increase in egg weight. This was accompanied by a delay in the increase in osteoid formation and decreased levels of blood ionised calcium. This led to high "on farm" seconds at late lay due to abnormally high fracture toughness and the Incidence of type B's within the mammillary layer. (10). The reason for the observed decrease in hatchability associated with poorly pigmented eggshells in a commercial guinea fowl flock was related to premature expulsion of the egg. These thinner shelled eggs may have resulted from the process of artificial insemination.
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Calvert, Nick. "Composite Hydrogel Scaffolds with Eggshell Particles as a Novel Bone Regeneration Material." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39481.
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The development of bone regeneration materials to support new bone formation is an active field of research. This report describes the development and characterization of a novel composite scaffold made of a chitosan-alginate co-polymer hydrogel matrix and eggshell (ES) particles. Scaffolds with ES particles or with nanotextured ES (NTES) particles following treatment with phosphoric acid were compared to scaffolds without particles. The scaffolds with particles exhibited a higher porosity and a larger median pore size. Their mechanical strength remained low, but both scaffold types were more resistant to deformation following compression than the scaffolds without particles. The osteogenic potential of the scaffolds was then evaluated with human bone-marrow derived mesenchymal stem cells (MSCs) from four different donors. Results showed that the inclusion of ES or NTES particles significantly increased MSC adherence and viability, as well as alkaline phosphatase activity in the scaffolds. A change of cell morphology and a small, although not statistically significant, increase of osteogenic protein expression (RUNX2 and osteopontin) were also observed at later time points (days 14 and 21). Overall, this research highlights the potential of ES for bone regeneration applications, opening the door for a high-value repurposing of a current industrial waste product.
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Koch, Lauren Elizabeth, and Lauren Elizabeth Koch. "Molecular and Biochemical Characterization of Chorion Peroxidases During Eggshell Formation in Aedes aegypti." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/625023.
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Female Aedes aegypti mosquitoes are biological vectors for arboviruses. Vertebrate blood contains the necessary nutrient content to produce eggs, and thus, blood-feeding triggers vitellogenesis and oogenesis. The pathway for proper eggshell formation includes key proteins belonging to the chorion peroxidase (CP) gene family, which have been found to contribute to stability of the eggshell and egg viability. This study aims to characterize the role of CP enzymes in oogenesis and eggshell formation with the intent of identifying genetic targets to reduce the fertility of the A. aegypti population and reduce spread of disease. CP enzymes 1-3 and 7 have been characterized locally and temporally via in situ hybridization and qPCR. CP enzymes are likely secreted extracellularly by oocytes, as mRNA encoding these enzymes are continuously present following follicular epithelial cell shedding. Temporally, data shows that CP1-3 expression is upregulated 36 hours post-blood meal (PBM), whereas CP7 is constitutively expressed immediately PBM. RNAi studies on these CP showed that CP1-3 exhibit eggshells that appear similar to wild-type or Fluc controls, whereas CP7-deficient mosquitoes oviposited eggs with anterior outgrowth formation. These studies suggest that CP7 is likely necessary during eggshell formation and could be a viable genetic target for mosquito pesticide.
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Mineo, Alessandro. "Mechanisms of restricted activation of the Torso receptor: from the eggshell to the embryo." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/402625.
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The establishment of the embryonic axis in the Drosophila embryo relies on four maternal systems. Anterior and posterior axes rely on morphogens located at the poles that will generate a gradient of activity along the embryo. In contrast, terminal and dorsoventral system rely on cues that are generated by follicle cells in the egg chamber to induce the restricted activation of their receptors, Torso and Toll respectively. In the case of the terminal signaling, the torso (tor) gene encodes for a tyrosine kinase receptor uniformly localised all around the membrane of the embryo but exclusively activated at the poles upon the activity of the Torso-like (Tsl) protein. Restricted activation of the Torso receptor at the embryonic poles relies on the tsl gene. Indeed, Tsl is expressed at the poles of the egg chamber during oogenesis and, in embryogenesis, accumulates at both poles of the inner side of the vitelline membrane, the innermost eggshell layer, by means of three protein encoded by the Nasrat (f(s) N), Polehole (f(s) Ph) and Closca (clos) genes. f(s) N, f(s) Ph and clos encode for proteins that localise in the vitelline membrane and are involved in the crosslinking of the vitelline membrane converting the eggshell into a stiff and insoluble layer. Indeed, females bearing mutations in any of
these genes produce collapsed eggs due to defects in their eggshell. fs(1)N12, fs(1)ph1901 and clos1
are the only point mutation alleles which do not abolish the integrity of the vitelline membrane but cause the lack of terminal structures.
The main objective of this work was to shed light on the role of Tsl, Nasrat, Polehole and Closca in ensuring restricted of Tor activation at the embryonic poles.
In the case of Tsl, we found that, during oogenesis, it accumulates at the vitelline membrane while, in embryogenesis it localises at both ends of the embryonic plasma membrane probably at egg activation. These results suggest a a mechanism to transfer the Tsl from the egg chamber to the early embryo. This mechanism relies on the initial anchoring of Tsl at the vitelline membrane as it is secreted by the follicle cells, followed by its later translocation to the egg plasma membrane.
In the case of Nasrat, Polehole and Closca,we found that embryo laid by fs(1)N12, fs(1)ph1901 and
clos1 mutant females display defects in dorsoventral patterning specification besides their terminal phenotype. Nasrat, Polehole and Closca, are required for proper anchorage and activity of Nudel, a protease acting both in embryonic dorsoventral patterning and vitelline membrane integrity, thus providing a mechanism for the role of Nasrat, Polehole and Closca in vitelline membrane cross linking and dorsoventral patterning. Therefore, the dorsoventral and terminal systems, hitherto considered independent, share a common extracellular mechanism constituted by the Nasrat, Polehole and Closca proteins. Moreover, we found that these proteins have a new Tsl-independent role in terminal signaling. In the embryonic terminal system, Tor is activated only at the poles by its ligand
Trunk while, in Drosophila larvae, Tor is also expressed and activated by another ligand called Prothoracicotropic hormone (PTTH) in the Prothoracic Gland. Ectopic expression of PTTH in the embryo is able to activate Tor ectopically even in the absence of Tsl but requires Nasrat, Polehole and Closca.
From these results, we propose that a Nasrat/Polehole/Closca complex acts as a multifunctional hub to anchor various proteins synthesized at oogenesis, ensuring their spatial and temporal restricted function. These findings shed light on the eggshell not just as protective layer but as a specialised extracellular matrix that regulates the spatial and temporal control of early embryonic developmental processes.El eje antero-posterior del embrión de Drosophila se especifica por acción de tres sistemas maternos: el sistema anterior, el sistema posterior y el sistema terminal. En el sistema terminal el receptor tirosina quinasa Torso (Tor) está localizado uniformemente en la membrana del embrión temprano pero se activa sólo en los polos por acción de la proteína Torso-like (Tsl). Aunque el papel de Tsl en la activación de Tor no está del todo claro, se ha descrito que Tsl es la única proteína de todo el sistema terminal localizada en los polos. De hecho, Tsl se acumula en la cara interna de la membrana vitelina (MV), anclado a las proteínas Nasrat, Polehole y Closca. El papel molecular de estas proteínas es poco conocido, pero análisis genéticos han demostrado que se necesitan para una correcta estructura de la MV y también para la activación de Tor. En esta tesis, nos hemos focalizado en la función de las proteínas Tsl, Nasrat, Polehole y Closca y su papel en la activación de Tor en los polos. Respecto a Tsl, descubrimos que esta proteína se acumula en la MV durante la oogénesis y, al principio de la embriogénesis, transloca de la MV a la membrana plasmática del embrión. En cuanto a Nasrat, Polehole y Closca descubrimos que estas proteínas se necesitan también para la correcta localización y función de Nudel, una proteína involucrada en la especificación del eje dorso ventral del embrión. Además encontramos que Nasrat, Polehole y Closca tienen una función adicional en el sistema terminal independiente de Tsl. De los resultados aquí descritos proponemos que un complejo formado por las proteínas Nasrat, Polehole y Closca podría funcionar en la MV como un centro multifuncional para anclar proteínas importantes por la especificación de los ejes del embrión.
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Chowdhury, Shankar R. "Effects of dietary 1,4-diaminobutane (putrescine) on eggshell quality and performance of laying hens." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61883.pdf.
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Fraser, Alexander Charles. "Environmental and physiological factors influencing the formation of the eggshell of the domestic fowl." Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318745.
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Duval, Camille. "Is eggshell pigmentation a condition-dependant strategy? : implications for egg crypsis in Japanese quail." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4825/.
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Avian eggshell colouration fulfills multiple adaptive functions, including egg camouflage. The potential role of the two main eggshell pigments in oxidative stress, biliverdin and protoporphyrin, may be behind a relationship between female immunocompetence and eggshell pigment investment strategies. In this study, environmental conditions were manipulated during different life cycle stages, via a variety of methods, including food-restriction and stress hormone exposure in female Japanese quails (Coturnix coturnix japonica), in order to experimentally test the condition-dependence of eggshell pigmentation, and to give first insights into the possible implications for egg crypsis. I demonstrated that eggshell pigmentation strategy is not only affected by female current body condition, but is also shaped by its early life experience such as exposure to stress, and that eggshell colouration is a key factor involved in egg crypsis in Japanese quail. Eggshell colour and maculation were both independently affected by breeding conditions; which stresses the complexity of the relationship between eggshell pigment concentrations and its appearance. My findings imply that eggshell appearance is a female extended phenotypic trait, and that trade-offs between eggshell pigmentation and immune-functions may lead to inter-females differences in their ability to maximise egg crypsis.
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Nolan, Lauren Wood. "EVALUATION OF CURRENT AND EMERGING TECHNIQUES FOR MEASURING EGGSHELL INTEGRITY OF THE DOMESTIC FOWL." UKnowledge, 2019. https://uknowledge.uky.edu/animalsci_etds/108.
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This dissertation is an investigation into the effect of different zinc sources and levels on eggshell quality and microstructure, as well as keel bone damage. Eggshell function is two-fold; eggshells function to protect the developing embryo, as well as act as a barrier against bacterial penetration, optimizing food safety of the egg for human consumption (Mabe et. Al., 2003). Two small trials were conducted in order to determine differences in eggshell microstructure of eggs produced from hens at peak lay (26 weeks of age) and at the end of lay (88 weeks of age). Two groups of hens were fed a calcium sufficient or a calcium deficient diet. From this it was determined that eggs with higher breaking strengths had some differences in eggshell microstructure. Eggs with greater breaking strengths had a greater density of ‘normal’ structures, compared to ‘abnormal’ structures. Additionally, eggs requiring a greater breaking force, had a thicker micro-structure, compared to shells requiring less breaking force. With this knowledge on microstructure, a larger, 36-week study was conducted using different zinc sources. Every four weeks, eggs were collected and standard egg quality measurements were taken and keel bones were scored. At the end of the study, keel bones were collected from randomly selected hens representing each treatment. Picture of these keel bones were taken and measurements were taken to determine type and degree of deformation, in comparison to scores taken on the live bird. Pens selected for keel bone analysis, were the same pens that eggs were taken for imaging by the scanning electron microscope, to determine eggshell microstructure. From this data, it was determined that egg quality differences were detected, as well as differences in eggshell microstructure. Additionally, keel bone scores progressively worsened throughout the 36-week long study, with type and degree of deformation differing depending on zinc source.
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Nascimento, Vladimir Pinheiro do. "The ease of translocation of Salmonella enteritidis through the eggshell wall : an immunocytochemical/ultrastructural study." Thesis, University of Glasgow, 1992. http://theses.gla.ac.uk/3893/.
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Evidence is presented to indicate that: a) The cuticular layer of the shell is rarely present as an even covering at any stage in the laying year. So, its role as a first line of defence is questionable. b) The shell membranes do inhibit bacterial transfer to some degree, even when they are structurally disrupted; however, if the challenge is great enough, then their function as effective barriers is reduced. c) In the absence of the shell membranes, Salmonella enteritidis Phage type 4 does not move freely across the shell, but it is either facilitated or inhibited in its passage by structural variation in the true shell, particularly at the level of the mammillary layer. Statistical data support in most instances a significant and positive correlation between the presence of structural defects and bacterial transfer. d) In a three tier battery system, a tier effect exists with respect to ease of translocation of microoganisms, with eggs from the top tier being more susceptible, i.e. structurally inferior. e) The results confirm earlier work that shell quality declines with age, and extends this finding to show that this morphological deterioration is accompanied by a decreased resistance to bacterial movement. f) Patent gas exchange pores, whilst obvious portals for bacterial ingress, are in this respect of secondary importance to structural defects within the shell. Evidence is also provided to substantiate the assumption that birds, irrespective of strain, display diverse shell structural quality. One of the strains evaluated (strain B) was structurally better than the other (strain A), at the beginning and middle of lay, and was also more capable of withstanding bacterial challenge in all three laying periods tested. 4. The housing system can influence shell quality; thus Barn and Battery eggs were structurally superior to their Range counterparts, at the end of lay. 5. The tagging of Salmonella with immunogold markers proved to be a valuable technique, which allowed a more precise localisation of the bacteria within the shell's ultrastructure, as viewed by the Scanning Electron Microscope (S.E.M.). This method gave support to other findings in this work, confirming that bacterial transfer was specifically encouraged by late fusion and alignment of the mammillae and pitting occurrences, with the cone layer probably implicated in the process of penetration in vivo. (now derestricted)
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Scharlemann, Jorn Peter Wolfgang. "Factors affecting long-term changes in eggshell thickness and laying dates of some European birds." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620699.
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Moore, Revelyn M. "Histochemical and ultrastructural studies of oogenesis, vitellogenesis and eggshell formation in acanthoparyphium spinulosum (trematoda: echinostomatidae)." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1985. http://digitalcommons.auctr.edu/dissertations/3595.
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This investigation presents a composite of the cytolog-ical events of oogenesis, vitellogenesis and eggshell formation at the ultrastructural level in a poorly known echinostomid trematode, A. spinulosum. For comparison, histochemieal methods which demonstrate basic proteins, phenols and phenolase were used to identify reproductive structures which produce eggshell precursors of the quinone-tanning system. It was observed that the tanning, system is localized specifically in the shell globules of vitelline cells and eggshells. Through transmission electron microscopy (TEM), it was observed that organization of the granular endoplasmic reticulum and Golgi complex is associated with synthesis of cortical granules in dveloping oocytes. At the onset of maturation of ova, the cortical granules are characteristically arranged immediately beneath the plasma membrane. The nucleus of mature oocytes have dispersed chromatin, which suggests that oogenesis proceeds as far as the diplotene stage of the first division of meiosis. Furthermore, it was observed that "nucleolus-like bodies" occur in close association with mitochondria in these cells. However, the significance of this phenomenon is not clearly understood. The vitelline follicles contain cells in various stages of vitellogenesis and a number of nurse cells. In contrast to immature cells, maturing vitelline cells are characterized by a well-organized granular endoplasmic reticulum and Golgi complex, which are associated with the synthesis of shell globules. These globules are arranged beneath the plasma membrane of mature cells. These cells also contain copious amounts of lipid droplets and glycogen granules. In addition, it was observed that cytoplasmic extensions of nurse cells form junctional complexes with vitelline cells, suggesting that a mechanism of selective transport exists between these cells. There is evidence that initiation of eggshell formation occurs in the distal ootype and proximal uterus. Reticular secretions from membranous body cells of Mehlis * gland were seen on the inner and outer surfaces of egg capsules in these regions. Granular secretions from dense body cells of Mehlis* gland were also observed adhering to egg capsules in the distal uterus. In contrast to young eggs, the older shells are several times thicker and appear to be blotched with electron-lucid areas, some of which have finely granular cores. It is suggested that the appearance of the older capsules may represent some phase of the tanning process. In summary, egg formation in Acanthoparyphium spinulosum appears to follow the general pattern of most other trematodes. However, when comparing oogenesis and vitellogenesis of A_. spinulosum to those processes in other trematodes, particularly Schistosoma mansoni and Fasciola hepatica, a greater variance was observed in the histochemistry and ultrastructure of mature vitelline cells. The degree of variance among species may be a reflection of differences in environmental factors which affect development of the eggs.
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Chowdhury, Sachchidananda Das. "Effects of feeding osteolathyrogens to laying fowls (Gallus domesticus) with particular reference to eggshell and membrane quality." Thesis, Imperial College London, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340864.
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Chien, Yung-Ching. "Matrix protein-mineral interactions in avian eggshell and during calcium carbonate and calcium oxalate crystal growth in vitro." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86659.
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In many normal and pathologic calcified tissues, osteopontin (OPN) is a prominent protein intimately associated with biominerals. This work aims to elucidate how OPN regulates crystal growth in two biosystems: calcitic avian eggshell during growth and resorption, and in vitro calcium oxalate dihydrate (COD) growth related to pathologic urolithiasis (kidney stones).To understand how OPN and other proteins participate in calcite growth and organization in avian eggshell, ultrastructural matrix-mineral relationships of unfertilized, unincubated chicken eggshell were examined using scanning and transmission electron microscopy (SEM and TEM). OPN was localized in situ in eggshell with high resolution colloidal-gold immunolabeling, and the effects of this protein on calcite growth were assessed in vitro. The detailed ultrastructures described here reconcile, for the first time, how an extensive organic matrix coexists with the calcitic mineral phase in eggshell. OPN preferentially binds to the {104} crystallographic face and subsequently occludes into the mineral, and thus directs calcite orientation by influencing crystal growth and morphology in eggshell. Moreover, OPN accumulates at interfacial boundaries between various eggshell compartments, maintaining the structure of eggshell compartments and the patency of eggshell pores by inhibition of mineralization at these interfaces.
Once constructed, the eggshell can serve as a calcium source for skeletal mineralization in the growing embryonic chick. Ultrastructural changes within the eggshell mammillae during shell resorption by chick embryo were examined systematically by SEM. The results suggest that the extensive mineral-occluded matrix network in mammillae may regulate dissolution of shell mineral by providing channels facilitating calcium release.
To investigate OPN related to COD formation common in urolithiasis, the effects of full-length OPN, and a poly-aspartic acid-rich peptide of OPN (DDLDDDDD, poly-Asp86-93), were examined in COD crystal growth studies. By combining SEM, light and confocal microscopy using fluorescently tagged poly-Asp86-93, together with computational modeling, it was observed that OPN and poly-Asp86-93 similarly inhibit (and thus enhance) the {110} faces of COD, and that the peptide is occluded into the COD crystals - this identifies an important motif involved in OPN binding to COD.
Collectively, these data provide new insights into how OPN and its peptides (and likely other proteins) bind to, and are occluded within, various biominerals to regulate crystal growth, and in some cases, to facilitate mineral dissolution.
Dans beaucoup de tissus calcifiés normaux et pathologiques, l'ostéopontine est une protéine de premier plan qui est intimement associée aux biominéraux. Cette étude vise à déterminer comment l'ostéopontine controlle la croissance cristalline dans deux biosystèmes : la calcite de coquilles d'oeuf aviaire durant sa croissance et sa résorption, et la formation in vitro d'oxalate de calcium dihydraté associé à l'urolithiase (calculs rénaux) pathologique.
Pour comprendre comment l'ostéopontine et d'autres protéines participent à la croissance et à l'organisation de la calcite dans la coquille d'oeuf aviaire, on a étudié, à l'aide d'un microscope électronique à balayage (MEB) et d'un microscope électronique à transmission (MET), les relations ultrastructuralles entre les matrices organique et minérale de coquilles d'oeuf de poule non fertilisé et non incubé. L'ostéopontine a été localisée in situ dans la coquille d'oeuf par immunomarquage à haute résolution à l'aide d'or colloïdal et les effets de cette protéine sur la croissance de la calcite ont été évalués in vitro.
Les ultrastructures détaillées décrites ici montrent pour la première fois la coexistence d'une matrice organique étendue et de la phase calcitique minérale dans la coquille d'oeuf. L'ostéopontine se lie de préférence à la face cristallographique {104}, pour ensuite s'occlure dans le minéral et diriger ainsi l'orientation des cristaux de calcite en influençant la croissance et la morphologie cristalline dans la coquille d'oeuf. Qui plus est, l'ostéopontine s'accumule au niveau des joints interfaciaux entre les différents compartiments de la coquille d'oeuf, maintenant la structure de ces compartiments et la perméabilité des pores de la coquille en inhibant la minéralisation sur ces joints interfaciaux.
Une fois construite, la coquille d'oeuf peut servir de source de calcium pour la minéralisation du squelette de l'embryon lors de son développement. Les changements ultrastructuraux dans les mamelons qui se forment sur la coquille lors de sa résorption par l'embryon ont été systématiquement examinés au microscope électronique à balayage. Les résultats permettent de penser que l'important réseau matriciel minéral occlus présent dans ces mamelons pourrait réguler la dissolution des minéraux de la coquille en fournissant des voies favorisant la libération du calcium.
Pour étudier l'ostéopontine associée à la formation d'oxalate de calcium dihydraté lors de l'urolithiase, on s'est penché sur les effets de l'ostéopontine pleine longueur et d'un peptide d'ostéopontine riche en acide polyaspartique (DDLDDDDD, poly-Asp86-93) dans des études de la croissance de cristaux d'oxalate de calcium dihydraté. En combinant la microscopie électronique à balayage, la microscopie optique et la microscopie confocale utilisant du poly-Asp86-93 marqué par fluorescence, ainsi que la modélisation assistée par ordinateur, on a observé que l'ostéopontine et le poly-Asp86-93 inhibent de façon similaire (et donc renforcent) les faces {110} de l'oxalate de calcium dihydraté et que le peptide est occlus dans les cristaux de ce dernier - ce qui identifie un important motif impliqué dans la liaison de l'ostéopontine à l'oxalate de calcium dihydraté.
Collectivement, ces résultats donnent un nouvel aperçu de la façon dont se lient l'ostéopontine et ses peptides (de même que d'autres protéines, probablement) et leur occlusion au sein divers biominéraux afin de réguler la croissance cristalline et, dans certains cas, de faciliter la dissolution minérale.
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Russo, João Paulo Vasconcelos Mendes. "Eggs and eggshells of Crocodylomorpha from the Upper Jurassic of Portugal." Master's thesis, 2015. http://hdl.handle.net/10362/16900.
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Crocodylomorph eggs are relatively poorly known in the fossil record when compared with skeletal remains, which are found all over the world, or when compared with dinosaur eggs. Herein are described crocodiloid eggshells from the Upper Jurassic Lourinhã Formation of Portugal, recovered from five sites: Cambelas (clutch), Casal da Rola, Peralta (eggshell fragments), and Paimogo North and South (three partial crushed eggs and eggshell fragments). The clutch of Cambelas, composed of 13 eggs, is the only sample not found in association with dinosaur eggshells. Morphological characters of the eggshells described herein, such as shell units and microstructure, are consistent with the crocodiloid morphotype. As such, this material is assigned to the oofamily Krokolithidae, making them the oldest known crocodylomorph eggs so far and the best record for eggs of non-crocodylian crocodylomorphs. Two new ootaxa are erected, Suchoolithus portucalensis oogen. et oosp. nov, for the clutch of Cambelas, and Krokolithes dinophilus, oosp. nov., for the remaining eggshells. The basic structure of crocodilian eggshells has remained stable since at least the Late Jurassic. Additionally, the findings suggest previously unknown biological associations with contemporary archosaurs, shedding light on the poorly understood egg morphology, reproduction strategies and paleobiology of crocodylomorphs during the Late Jurassic.
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Feng, Pei-Hsuan, and 馮珮宣. "Study on Cracks Detection of Eggshells by Using Resonant Inspection Method and Identified by Support Vector Machine." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/61800134023469273866.
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碩士國立中興大學
生物產業機電工程學系所
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Cracks of eggshells will not only affect the preserved time, but also reduce the successful rate of the processed products. Therefore, this study will base on the theory of resonant inspection, and it was verified by the Support Vector Machine（SVM）. The principle is that recording the signal data by using microphone and accelerator. Then, it used the FFT analyzer by fast Fourier transform to execute the signal analysis. To distinguish perfect and cracked eggs, it was found by comparing the resonant frequency and amplitude used microphone and accelerometer as the sensor, Secondly, the results was verified by Support Vector Machine both of method are successful. However, the microphone sensor is better. The results showed that the characteristic frequency of the perfect egg was 4130 ~ 5500Hz and its amplitude was 0.16 ~ 0.20V.However, the spectrum of the cracked egg was messy with no obvious characteristic frequency, and the maximum amplitude was 0.06V. This feature was judged by SVM, and the identification accuracy can reaches to 99% and 98% for training set and the testing set. If that is not knock on the paddy or lump of soft soil on the eggshell, Microphones are used in dirty eggs and crack eggs, and the results of SVM accuracy could reaches to 100% and 100% for training set and the testing set. The conclusion is that resonance detection method to determine the cracks of eggshells is an effective method.
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Hughes, R. J. (Robert J. ). "Influence of dietary electrolytes on blood acid-base balance in relation to formation of egg shells in the domestic hen." 1989. http://web4.library.adelaide.edu.au/theses/09A/09ah894.pdf.
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Correia, Telmo Alexandre Ferreira. "Mercury elimination by shorebirds using temperate and tropical wetlands." Master's thesis, 2021. http://hdl.handle.net/10773/31921.
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Mercury pollution is a global issue due to atmospheric transport and its bioaccumulation by organisms, resulting in several adverse effects on wildlife. Migratory shorebirds use several wetlands at different latitudes where mercury pollution is likely to differ. Little is currently known about mercury levels in shorebirds in tropical regions. In this study, we assessed mercury levels in freshly grown feathers of several shorebirds species wintering in two important wetlands of East Atlantic Flyway: Bijagós Archipelago (tropical; Calidris alba, Calidris canutus, Charadrius hiaticula, Tringa totanus, Actitis hypoleucos, Arenaria interpres, Calidris ferruginea and Pluvialis squatarola) and Tagus Estuary (temperate; Calidris alba, Calidris canutus, Charadrius hiaticula, Tringa totanus, Calidris alpina and Limosa limosa). We also assess mercury levels of breeding species, by analysing eggshells of Charadrius alexandrinus and Himantopus himantopus, collected in saltpans of the Ria de Aveiro and of the Tagus Estuary, and in the faeces of the last species collected mostly throughout the non-breeding season. Mercury levels in feathers and eggshells varied significantly among species and wetlands. The results showed that, in general, shorebirds wintering in Tagus Estuary had higher mercury concentrations (2.106±0.681 – 9.918±3.499 ppm) than those from Bijagós Archipelago (0.932±0.369 – 2.773±0.784 ppm), suggesting that mercury exposure is higher in this temperate wetland. Charadrius alexandrinus eggshells had higher concentrations in both portuguese wetlands (0.034±0.006 e 0.037±0.006 ppm) than Himantopus himantopus ones (0.018±0.004 e 0.009±0.002 ppm). The Himantopus himantopus faeces contained detectable mercury but the mean concentrations (0.040±0.003 – 0.085±0.025 ppm) did not vary over the season. The differences observed in this study were likely caused by spatial differences in mercury pollution between wetlands and by interspecific differences on trophic habits of species. Overall, mean mercury levels in feather were below the toxicity threshold effect level (5ppm), with two notable exceptions: Tringa totanus and Calidris alba from Tagus Estuary.A poluição por mercúrio é um problema global devido ao transporte atmosférico e á sua bioacumulação pelos organismos, resultando em efeitos adversos na vida selvagem. As aves limícolas migratórias exploram diversas zonas húmidas em diferentes latitudes onde a poluição por mercúrio pode ser distinta. Pouco se sabe acerca dos níveis de mercúrio nas aves limícolas em regiões tropicais. Neste estudo determinaram-se os níveis de mercúrio em penas recém desenvolvidas de aves limícolas invernantes em duas importantes zonas húmidas integradas na Rota Migratória Este Atlântico: Arquipélago dos Bijagós (tropical; Calidris alba, Calidris canutus, Charadrius hiaticula, Tringa totanus, Actitis hypoleucos, Arenaria interpres, Calidris ferrugínea and Pluvialis squatarola) e Estuário do Tejo (temperado; Calidris alba, Calidris canutus, Charadrius hiaticula, Tringa totanus, Calidris alpina and Limosa limosa). Avaliaram-se também os níveis de mercúrio nas cascas de ovos de Charadrius alexandrinus e Himantopus himantopus, nidificantes nas salinas da Ria de Aveiro e do Estuário do Tejo, e nas fezes da última espécie referida recolhidas maioritariamente fora da época de nidificação. Os níveis de mercúrio nas penas e nas cascas de ovos variaram significativamente entre espécies e entre zonas húmidas. Os resultados mostraram que de uma forma geral, as aves limícolas invernantes no Estuário do Tejo apresentaram concentrações de mercúrio mais elevadas (2.106±0.681 – 9.918±3.499 ppm) do que as do Arquipélago dos Bijagós (0.932±0.369 – 2.773±0.784 ppm), sugerindo que a exposição é maior nessa zona húmida temperada. As cascas de ovos de Charadrius alexandrinus apresentaram concentrações mais elevadas de mercúrio, em ambas as zonas húmidas portuguesas (0.034±0.006 e 0.037±0.006 ppm), do que as de Himantopus himantopus (0.018±0.004 e 0.009±0.002 ppm). As fezes de Himantopus himantopus continham mercúrio detetável, mas as concentrações médias (0.040±0.003 – 0.085±0.025 ppm) não variaram ao longo dá época. As variações observadas neste estudo foram provavelmente causadas por diferenças espaciais na poluição por mercúrio entre as zonas húmidas estudadas e também por diferenças interespecíficas nos hábitos tróficos das espécies. As concentrações de mercúrio nas penas estiveram genericamente abaixo do nível de efeito do limiar de toxicidade (5ppm), com duas exceções assinaláveis: Tringa totanus e Calidris alba do Estuário do Tejo.
Mestrado em Ecologia Aplicada
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Wagner, Kerstin. "Effect of local changes to shell permeability on the gas exchange of the avian embryo / by Kerstin Wagner." 2000. http://hdl.handle.net/2440/20304.
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Bibliography: leaves 148-166.xi, 166 leaves : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
The chicken embryo's ability to match the perfusion of its chorioallantoic membrane to regional differences in shell conductance was investigated.
Thesis (Ph.D.)--Adelaide University, Dept. of Environmental Biology, 2001