Structural and physical changes in the hen's eggshell in response to the inclusion of dietary organic minerals.

1. An experiment was designed to determine whether the inclusion of sodium selenite, Sel-Plex or Sel-plex + Bioplex in the diet exerted any influence on structural and functional properties of the eggshell at 22, 38, 58 and 72 weeks age. 2. Significant age effects were demonstrated for egg weight, dynamic stiffness and total shell thickness. 3. The eggshells from birds fed on the Sel-Plex + Bioplex treatment were statistically stronger than those produced by the birds on sodium selenite. 4. From mid-lay onwards the shells laid by birds fed on the Sel-Plex + Bioplex treatment displayed, at ultrastructural level, the crystal modification termed 'confluence' together with early fusion of the palisade columns which comprised the bulk of the shell. 5. At all periods of lay the shells of birds fed on sodium selenite, Sel-Plex and the control diet demonstrated the presence of a variety of crystalline aggregates localised between the forming palisade columns.

The eggshell: strength, structure and function.

In making a journey through the literature of the last 50 years one can easily highlight a sequence of seminal works-but the route has not been direct and to avoid the many profitable diversions and detours that have enriched and deepened our collective understanding of the subject of eggshell structure and function is to do the subject a serious disservice. This is a route march of science enabled by advances in technology.

Enantioselective synthesis of imperanene, a platelet aggregation inhibitor.

Both enantiomers of imperanene, a platelet aggregation inhibitor, have been synthesized in 82-90% ee. The key step of establishing the chiral center was achieved through stereoselective alkylation with benzyl chloromethyl ether using Enders' RAMP/SAMP chiral auxiliary method. The natural product was determined to be the (S)-enantiomer through comparison of optical rotation data. Reaction: see text.

Bisphosphonates: a potential role in the prevention of osteoporosis in laying hens.

Osteoporosis in layers is associated with the modelling and remodelling of medullary bone. Cancellous bone volume (CBV) decreases initially during medullary bone modelling and continues to decrease during subsequent remodelling. In an attempt to maintain peak structural bone mass, the bisphosphonate, alendronate, was administered to pullets before medullary bone modelling. At point of lay CBV was significantly greater (P<0.01) in the alendronate group (17.59 per cent) than in controls (13.79 per cent), while medullary bone volume (MBV) was not significantly affected. After 20 weeks, CBV remained significantly higher (P<0.02) in the alendronate group (12.72 per cent) than in controls (9.80 per cent) and MBV was lower in the alendronate group than the control group. CBV was however reduced and MBV increased in both groups compared with values at point of lay. Alendronate therefore appeared to prevent the bone loss associated with medullary bone modelling but not that which occurs during remodelling.

On an island by myself: women of color with facial distinctions.

Twenty-five women of color with early or late-onset facial distinctions between the ages of 18 and 44 were interviewed as part of a larger study investigating the psychosocial sequelae of facial distinction. Women were asked to report their thoughts about the ways other people perceived them, about their self-perceptions, and about difficult aspects of having a facial distinction. Findings indicate that facial distinction is a salient, pervasive, and overwhelming physical attribute. Society exerts a negative influence on all people with distinctions. This is accomplished by strictly defining what is an acceptable physical appearance and what is not and excluding those who do not conform to the standard. The findings point towards new areas for research including cross-cultural, cross-gender, and cross-distinction studies. Recommendations for clinical intervention are offered.

Nuclear mitochondrial-like sequences in ants: evidence from Atta cephalotes (Formicidae: Attini).

Nuclear mitochondrial-like sequences (numts) are copies of mitochondrial DNA that have migrated to the genomic DNA. We present the first characterization of numts in ants, these numts being homologues to a mitochondrial DNA fragment containing loci the 3' portion of the cytochrome oxidase I gene, an intergenic spacer, the tRNA leucine gene and the 5' portion of the cytochrome oxidase II gene. All 67 specimens of Atta cephalotes (Hymenoptera: Formicidae: Attini) investigated had these homologues, which are within two monophyletic groups that we called numt1 and numt2. Numt1 and numt2 sequences are less variable than mitochondrial sequences and released from the severe purifying selection constraining the evolution of mitochondrial genes. Their formation probably involved bottlenecks related to two distinct transfer events of ancient and fast evolving mitochondrial DNA fragments to comparative slowly evolving nuclear DNA regions.

Effect of environmental enrichment during the rearing phase on subsequent eggshell quality in broiler breeders.

This study set out to investigate if access to an enriched environment during the rearing phase influences subsequent production and eggshell quality in broiler breeders. Broiler breeder pullets were reared under standard rearing conditions (control treatment) or under standard conditions with an environmental enrichment of bales of plastic-wrapped wood shavings (enriched treatment). At 19 weeks of age both groups were transported to a laying facility and housed in standard pens according to treatment type. Egg weight, shape, shell thickness, non-destructive deformation, breaking strength, stiffness and ultrastructural quality were compared at beginning of lay (25 weeks old), peak production (31 weeks old), mid-lay (45 weeks old) and end of lay (57 weeks old). Production and hatchery data were also collected throughout lay. Significant treatment-age interactions were detected for non-destructive deformation, breaking strength and stiffness, such that birds which had received prior enrichment went on to maintain a better shell quality with age. The measurements of total shell thickness, mammillary thickness and effective shell thickness all showed a trend for a treatment-age interaction. Significant age effects were found for weight, shape index, shell thickness, breaking strength and stiffness. All production and hatchery data also demonstrated significant changes with age. It is concluded that early enrichment with bales of wood shavings may provide a novel approach to the maintenance of eggshell quality at a time when calcium metabolism begins to reduce in efficiency.

The localisation of beta-N-acetyl-glucosaminidase in the oviduct of the domestic fowl.

1. Beta-N-acetylglucosaminidase [EC 3.2.1.30] activity in the oviduct of the domestic fowl has been studied using biochemical and histochemical methods. 2. The principal source of the enzyme was the isthmus, where the enzyme was localised within the less dense region of the dual density granules which characterise this portion of the oviduct.

Gordon Memorial Lecture. An egg ist ein ei, es un huevo, est un oeuf.

1. Many of the mechanical tests devised to measure shell quality are inadequate because they fail to recognise the complex interaction between the organic and inorganic aspects of the eggshell. 2. Twelve structural modifications have been observed at the level of the mammillary layer and their presence correlated with a variety of environmental stress events. Occurring as they do in the basal layers of the shell, these morphological variants influence its mechanical properties. 3. The organic matrix proteins which complex with the calcium carbonate derive from a variety of sites within the oviduct and vary in their location within the fully formed shell. In vitro mineralisation reveals the significance of these proteins in the crystal growth mechanism. 4. The isolation and identification of the protein moiety in well-structured eggshells is an essential prerequisite to understanding the abnormalities in crystal growth observed in the shells of older birds challenged by disease and other undesirable 'on farm' events. 5. The eggshell is the daily indicator of the bird's harmony with its environment and as such provides a readily accessible and non invasive measure of welfare. The integration of these data with those derived from behavioural and biochemical testing should provide industry with a reliable numerical welfare index.

Studies on the isthmus region of the somestic fowl.

The isthmus extends from the aglandular zone, which delimits it from the magnum, to the tubular shell gland, which to the naked eye is marked by a distinct colour change from off-white to brown. 2. The surface epithelium comprises three cell types, ciliated, non-ciliated and mitochondrial, of which only the non-ciliated cells contribute towards the carbohydrate moiety of the shell membranes. 3. The gland cells are distinctive, containing granules of variable electron density, variations also occurring within individual granules. 4. Although two types of gland cell have been observed, they may merely represent different phases of development. 5. In the type 1 cell, the rough endoplasmic reticulum and Golgi complex are typical of the normal protein secreting cell; in the type 2 cell the RER is sparse, dilated and filled with intracisternal granules while the Golgi complex is likewise distended.

The characterisation and distribution of cells lining the axillary gland of the adult green turtle (Chelonia mydas L.).

The axillary gland of the marine turtle lies in the angle formed by the carapace and plastron. The gland is compound tubular and the secretions released by the various acini are conveyed to the exterior via a large excretory duct lined by stratified squamous non-keratinised epithelium. The main secretory areas are lined by holocrine cells, i.e. they degenerate on discharging their contents. The epithelium lining the short ducts which carry the holocrine secretions to the large excretory duct is invaginated regularly giving rise to shallow intraepithelial acini. The cells lining these acini are of two types, granular and mitochondrial. These cells communicate via complex infoldings of their lateral cell walls. The granular cells produce an acidic mucosubstance. The holocrine regions are embedded in a large amount of striated muscle and are separated from the latter by a band of collagen containing variable numbers of melanocytes. The short secretory ducts and large excretory duct have less muscle associated with them but there is a corresponding increase in the volume of collagen. When handled, the adult turtle ejects a milky fluid via the plastral pore. This pungent secretion is weakly acidic.

The morphology of the kidney of the green turtle (Chelonia mydas L.).

The kidneys of the green turtle are flattened, lobed and closely applied to the posterior wall of the pleuroperitoneal cavity. The ability to differentiate new functional nephrons is retained by five years old animals. The functional nephron comprises a glomerulus, proximal tubule, intermediate segment which can be subdivided into a proximal non-secretory segment and a distal mucus secreting segment, distal convoluted tubule and collecting tubule. Both the proximal and distal tubules exhibit complex foldings on their lateral cell walls in contradistinction to the characteristic basal infoldings observed in mammalian tubules.

The ultrastructure of the follicle wall of the domestic fowl during the phase of rapid growth.

The development of a standard technique for fixing the developing follicle for ultrastructural studies is described. 2. The follicle wall is shown to be a multi-layered structure which exhibits a number of morphological changes concomitant with yolk protein transfer, the most significant of which are the intercellular channels which form between the granulosa cells during the fast phase of protein transfer.

The respiratory epithelium of the lung in the green turtle (Chelonia mydas L.).

The chelonian lung exhibits reptilian, mammalian and avian features. The respiratory epithelium is typically vertebrate, i.e. pseudostratified columnar with cilia; gaseous exchange areas appear at all levels from the respiratory bronchi down to the alveoli. The latter are invested with a capillary network and both type I and type II cells are present. The possible functional significance of the distribution of collagen, elastic tissue, cartilage and smooth muscle is discussed.

The structure of the carapace and plastron of juvenile turtles, Chelonia mydas (the green turtle) and Caretta caretta (the loggerhead turtle).

Consistent with their primary function as a protective covering, the carapace and plastron are heavily keratinised. In both species, the carapace is heavily pigmented and during the development and translocation of basal cells from the germinal layer of the epidermis, pigment granules migrate towards the surface layers. The epidermis is generally 2-4 cells thick; however at the growing points it can attain 6 cell layers. The epidermis is much thicker over the plastron of the loggerhead turtle. The ultrastructure of the epidermal cells supports the observation that the keratin scales are of the hard variety and the microfolds which characterise the scutes covering the carapace are discussed in relation to the lowering of frictional drag in water.

Relationship between shell structure and movement of Salmonella enteritidis across the eggshell wall.

1. Ultrastructural analyses of the eggshells of one strain of commercial layers indicated that the cuticular layer is rarely present as an even covering over the shell surface and the paired shell membranes are invariably pitted with holes larger than bacterial dimensions. 2. The above conditions pertain irrespective of the age of the laying bird. 3. Bacterial penetration of the eggshell is independent of pore numbers. 4. In the absence of a functional cuticle and with the shell membranes removed, bacteria are checked in their movement by structural modifications in the mammillary layer.

Effect of a single injection of adrenaline on shell ultrastructure in a series of eggs from domestic hens.

1. Adrenaline (1 mg in 1 ml water) was administered subcutaneously to three hens to determine whether any changes in the shell ultrastructure of subsequent eggs would occur. 2. The egg shells were examined in a scanning electron microscope after plasma etching. 3. The first three eggs laid by each bird after adrenaline injection were compared with previously-collected normal eggs from the same birds and also with control eggs collected over the same period from three hens which had received no adrenaline. 4. The first egg laid following adrenaline treatment was essentially normal but both the second and third eggs showed severe structural disorganisation at all levels, from the mamillary caps up to the cuticular layer. 5. Eggs laid 20 d or more after adrenaline treatment had reverted to normal. 6. The findings suggest that the abnormal eggs laid after hens have been exposed to disturbance or stress are likely to be affected in not only their external appearance but also to be of poor structural quality.

Scanning electron microscopy of the respiratory epithelium of chicks fumigated with formaldehyde vapour.

1. Hatching chicks were exposed to 10.9 ppm of formaldehyde vapour during the last 3 d of incubation in a commercial situation. 2. Samples from pre-selected regions of the entire respiratory tract, taken at 0, 6, 30 and 54 h post-vaporisation of formaldehyde, were examined by scanning electron microscopy for surface morphological features and associated pathological changes. 3. Clumping of cilia, blebs on the cilial wall, deciliation and exfoliation of the epithelium were all observed under the scanning electron microscope. 4. Lesions were more severe in chicks exposed for 54 h as compared to those exposed for 6 and 30 h. There were no regional differences in the lesions throughout the respiratory tract of all the chicks. 5. Limited observations suggest that the passage of formaldehyde vapour across the egg shell wall may influence the morphology of the respiratory lining of the developing embryo.