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Our recent goal for the Plant Ontology (PO) is to have it integrated with the Gene Ontology (GO). The simplest aspect of this is to link morphological and anatomical images of structures for PO terms with genes involved in the development of those structures (GO terms). This, also, would include images of expression analyses by in situ hybridization. By using a process of reciprocal illumination, we will be able to clarify and/or redefine PO terms. In particular, an example of this is the integument development during ovule maturation in seed plants. Gymnosperms have one integument; whereas, Angiosperms (flowering plants) have two integuments, i.e., an inner integument surrounded by an outer integument. The question that arises is which of the two integuments in the Angiosperms is the equivalent of the single integument in the gymnosperms? In Angiosperms, the gene INNER NO OUTER (INO) is involved in the proper development of the outer integument but not in the inner integument and in ino mutants there is no outer integument. INO genes are angiosperm specific as no orthologs have been found in gymnosperms. Thus, it appears that the inner integument of the Angiosperms is equivalent –homologous- to the single integument of the gymnosperms and the PO terms can be revised accordingly. Keywords: Angiosperm, Gene ontology, Gymnosperm, Integument, Ontology, Ovule, Plant ontology

The integument is one of the most dynamic and important of organs. Having a unique role as a first line defense against numerous environmental insults (e.g., physical trauma, temperature fluctuations, infectious and chemical agents, ultraviolet radiation), the health of the skin impacts and reflects the health of the organism. In toxicologic pathology the skin may represent a target organ for those compounds that make direct contact with it, but it also may reflect changes in other internal organs (e.g., jaundice), serving as an external reflection of various internal pathophysiologic conditions. This chapter reviews the most important aspects of the skin as a toxicologically relevant organ.

A permineralized seed, Pachytestopsistayloriorum gen. et sp. nov., is described from the Changhsingian (upper Permian) Fort Cooper Coal Measures at the Homevale locality in the northern Bowen Basin, Queensland,Australia. This largest permineralized seed species yet recorded from Permian deposits of Gondwana conforms to a size accommodated by either Rigbyaceae or Lidgettoniaceae (glossopterid) fructifications recorded elsewhere in the Sydney-Bowen basin complex. The seeds are characterized by a thin endotesta of longitudinally orientated cells, thick mesotesta incorporating an inner band of very thick walled sclereids and an outer layer of thin-walled parenchymatous cells, and an exotesta that comprises a well-developed epidermis and several layers of thick-walled hypodermal cells. Vascular supply to the base of the seed passes through the integument and bifurcates into the nucellar pad. Taeniate bisaccate pollen of Protohaploxypinus-type occurs in the pollen chamber of the seed. A comparison of the characters of P. tayloriorum with other permineralized seeds from the Permian of Gondwana indicates that several of the characters used in previous phylogenetic analyses incorporating glossopterids are wrongly scored or ambiguous in their definition. Other funding from:Australian Research Council [grant number DP0557828]National Science Foundation (project 1636625)Deutsche Forschungsgemeinschaft (DFG project BO3131/1-1)

This chapter is focused on expressed proteins that organize to form softer connective tissues that are devoid of mineral content. Here, the composition and structure of various soft connective tissues are presented as links between the composition and resulting properties. There is a separate organizational structure to proteins composing soft tissues and issues of soft tissue orientation are addressed. Water contained within soft tissues makes up a large fraction of the extracellular matrix and ground substance, and essentially acts as a plasticizer to soften tissues dramatically altering their properties. There are known variants in both composition and structure that are natural and dynamic with age, and there are other variants that present as complications to normal physiologic function. Examples presented include those formed in the cardiovascular system, the integument which also includes hair and nails, and the muscular system with both similarities and distinctions.

The present study was designed to analyze the growth performance, behavioral patterns and intensity of injuries of weaned pigs (26 days) during a rearing period of 6 weeks. The farrowing system (group housing (GH) v. single housing (SH)) and the post-weaning regrouping weight class (light, medium, heavy) were considered as the main factors. A number of 120 GH-pigs and 120 SH-pigs were kept in three batches (20 pens, 12 pigs each). The GH- and SH-pigs were divided by weight into three groups: light (5 to ⩽7 kg), medium (>7 to ⩽9 kg) and heavy (>9 to ⩽12 kg), with two pigs of six different litters in each pen. The pigs were weighed individually at weaning (week 1) and during rearing (weeks 2, 3 and 7). The feed conversion ratio (FCR) was calculated between weeks 1 and 7. The duration and number of fights (NF) per pen and hour were determined by continuous sampling (40 h after weaning). Lesions of the integument were scored into four classes (none, minor, medium, severe) and recorded at weaning and 48 h afterwards. The farrowing system had no effect on the weights in week 1 (GH: 7.8 kg v. SH: 7.7 kg; week as linear, quadratic regression nested within housing systems) or in week 7 (GH: 29.4 kg v. SH: 28.6 kg). The body weights were influenced significantly by the weaning weight class (light: 11.7 kg (s.e.m.: 0.30), medium: 14.8 kg (s.e.m.: 0.22), heavy: 17.3 kg (s.e.m.: 0.26)). The FCR of the GH-pigs was 1.64 (s.e.m.: 0.03) and 1.58 (s.e.m.: 0.03) for SH-pigs. A reduced agonistic behavior of the GH-pigs was observed with 2.1 fights per pen and hour (s.e.m.: 0.07) v. the SH-pigs with 4.6 fights per pen and hour (s.e.m.: 0.05). The fight duration of the GH-pigs with 10.3 s per pen and hour (s.e.m.: 1.07) was significantly lower in comparison to the SH-pigs with 18.8 s per pen and hour (s.e.m.: 1.06). The SH-pigs had more new skin lesions at the shoulders than the GH-pigs 48 h after weaning (P < 0.05). In conclusion, early mixing of unacquainted litters during lactation had no influence on their growth performance during rearing but reduced agonistic behavior and lesion score difference during the first 2 days after weaning. No significant interaction between the farrowing system and weaning weight class was detected with regard to growth performance and NF.

The plastron theory was tested in adults of Neochetina eichhorniae Warner, 1970, through the analysis of the structure that coats these insects' integument and also through submersion laboratorial experiments. The tegument processes were recognized in three types: agglutinated scales with large perforations, plumose scales of varied sizes and shapes, and hairs. The experiments were carried out on 264 adult individuals which were kept submerged at different time intervals (n = 11) and in two types of treatment, natural non-aerated water and previously boiled water, with four repetitions for each treatment. The tests showed a maximum mortality after 24 hours of immersion in the previously boiled water treatment. The survival of the adults was negative and significantly correlated with the types of treatment employed and within the different time intervals. The values of oxygen dissolved in water (mg/l) differed significantly within the types of treatment employed. They were positively correlated with the survival of the adults in the two types of treatment, although more markedly in the treatment with previously boiled water. The mortality of adults after 24 hours of submersion in the treatment with previously boiled water may be associated with the physical-chemical conditions of the non-tested water in this study, such as low surface tension and concentration of solutes. These results suggest plastron functionality in the adults of this species. A teoria plastrão foi testada em adultos de Neochetina eichhorniae Warner, 1970, por meio da análise da estrutura que reveste o tegumento destes insetos e em experimentos laboratoriais de submersão. Os processos tegumentares foram reconhecidos em três tipos: escamas aglutinadas e com perfurações largas; escamas plumosas de tamanhos e formas variadas; e pêlos. Os experimentos realizados com 264 indivíduos adultos os quais permaneciam submersos por diferentes intervalos de tempo (n = 11) e em dois tratamentos, água natural não aerada e água previamente fervida, com quatro repetições para cada tratamento, revelaram uma mortalidade máxima após 24 horas de mergulho no tratamento água previamente fervida. A sobrevivência dos adultos foi negativa e significativamente correlacionada com os tratamentos empregados e entre os diferentes intervalos de tempo. Os valores de oxigênio dissolvido (mg/l) na água diferiram significativamente entre os tratamentos aplicados, sendo positivamente correlacionado com a sobrevivência dos adultos nos dois tratamentos, embora mais acentuadamente no tratamento com água previamente fervida. A mortalidade dos adultos após 24 horas de mergulho no tratamento com água previamente fervida pode estar associada às condições físico-químicas da água não testadas neste estudo, como, por exemplo, baixa tensão superficial e concentração de solutos. Estes resultados sugerem uma funcionalidade do plastrão nos adultos desta espécie.

The dermis is formed from one of several types of mesoderm (dermatome, lateral plate) or of neural crest, depending on the particular region of the body. The epidermis always forms from ectoderm, whatever the region of the body. Feather formation is discussed in relation to epithelial–mesenchymal interactions and in the light of modern molecular biological findings. Differentiation of beaks, claws, comb and uropygeal gland is considered briefly, as are the innervations and the growth of sensory receptors in the integument.

The integument or skin is the envelope that not only separates and protects a fish from its environment, but also provides the means through which most contacts with the outer world are made. It is a large organ and is continuous with the linings of all body openings, and also covers the fins. Fish integument is a multifunctional organ, and its components may serve important roles in protection, communication, sensory perception, locomotion, respiration, ion regulation, excretion, and thermal regulation.

The integument consists of skin and all its constituents, including hair, feathers, scales, horns, wattles, and all types of external structures. Because these structures are constantly exposed to abrasion, exposure to sunlight and weather, they must be replaced at regular intervals. In many species, skin is replaced more or less constantly, but in others, such as many reptiles, it may be shed every few months or yearly. Many sexually selected traits, such as bright nuptial skin or feathers, and antlers, are shed and regrown yearly. The periodic replacement of skin, hair, feathers, and scales is termed ‘molt.’ Although the hormonal control of integument replacement is progressing, the interrelationships of hormones and behavior associated with molt remain largely unexplored.

Publisher Summary This chapter discusses the mechanoreception, a sense that allows insects to detect their external and internal mechanical environments, including physical orientation, acceleration, vibration, sound, and displacement. The integument and internal organs contain a wide variety of mechanoreceptors. Prominent receptors, such as surface hairs that mediate touch, or auditory organs, have been studied extensively, but many other physiological functions also depend on mechanosensory signals. Arthropod mechanoreceptors are divided into two morphological groups: Type I, or cuticular, and Type II, or multipolar. Type I have ciliated receptors, associated with the cuticle, and have their nerve cell bodies in the periphery, close to the sensory endings. They can be subdivided into three major groups. Hair-like receptors are found on the outer surface in a variety of shapes and sizes, from long, thin hairs to short pegs and scales. A sensory neuron is closely apposed to the base of the hair, and its dendrite contains microtubules ending in a structure called the tubular body. It is assumed that movement of the hair compresses the ending, with the tubular body perhaps providing a rigid structure against which the compression can work.

Publisher Summary This chapter discusses exoskeleton, which is noncellular material located on top of the epidermal cell layer and constitutes the outermost part of the integument. The exoskeleton serves as a barrier between the interior of the insect and the environment, preventing desiccation and penetration of microorganisms. Muscles overning the insect's movements are attached to the exoskeleton. The exoskeleton is produced and modified by the epidermal cell layer, and each cell in the epidermis must have the necessary information for producing and depositing the right amount of the right cuticular components at the right time; later some of them will modify the secreted products to give a mature material. The muscles that act on the exoskeleton are connected to the basal surface of the epidermal cells by means of desmosomes. Some small exoskeletal regions are characterized by a rubberlike elasticity; they can undergo considerable deformation when exposed to mechanical stress and will return to their original shape when unstressed. Several exoskeletal structures are involved in sense perception. Various types of mechanoreceptor are involved in registering the exact position of, and deformation in, the various exoskeletal regions and body parts, movements of surrounding objects, currents of air or water, vibrations in the substrate, and sound oscillations. The mechanical properties of all exoskeletal regions are precisely adapted to be optimal for the lifestyle of the insect.

Publisher Summary The outer covering of insects is referred to both as an exoskeleton and an integument. The integument consists of the underlying basement membrane, the living epidermal cell layer, and the overlying, nonliving cuticle that is secreted by the epidermis. This chapter describes the integumentary systems in insects, their chemical composition, and their role in insect physiology. The components that constitute the exoskeleton make an overwhelming contribution to the terrestrial success that arthropods can claim. The exoskeleton completely covers the insect providing an armor-like protective suit as a skeleton, serves as an interface between the insect and the environment, determines the form of the insect body, and makes possible the dramatic changes in form that accompany metamorphosis. The molting process involves an elaborate sequence of events that produces a new cuticle capable of significant expansion before the old one is discarded. The process begins with the separation of the epidermal cells from the old cuticle, known as apolysis, and ends with the casting off of the old cuticle, known as ecdysis. It is the period between these two events when the components of the new cuticle are synthesized. The molting cycle is initiated and regulated by the endocrine system, and molting occurs as a result of the coordinated activity of all the epidermal cells in the insect, with hormones providing the means by which this coordination occurs. The basic hormonal mechanism is identical whether the molt is larval to larval, larval to adult, larval to pupal, or pupal to adult. A cascade of several neurohormones is responsible for eliciting eclosion behavior, including corazonin, ecdysis-triggering hormone (ETH), eclosion hormone (EH), crustacean cardioactive peptide (CCAP), and bursicon.

We develop a coherent view of the form and function of the integument of water-walking insects and spiders by reviewing biological work on the subject in light of recent advances in surface science. Particular attention is given to understanding the complex nature of the interaction between water-walking arthropods and the air–water surface. We begin with a discussion of the fundamental principles of surface tension and the wetting of a solid by a fluid. These basic concepts are applied to rationalize the form of various body parts of water-walking arthropods according to their function. Particular attention is given to the influence of surface roughness on water-repellency, a critical feature of water-walkers that enables them to avoid entrapment at the interface, survive the impact of raindrops and breathe if submerged. The dynamic roles of specific surface features in thrust generation, drag reduction and anchoring on the free surface are considered. New imaging techniques that promise important insights into this class of problems are discussed. Finally, we highlight the interplay between the biology, physics and engineering communities responsible for the rapid recent advances in the biomimetic design of smart, water-repellent surfaces.

This chapter reviews the structure and differentiation patterns of normal skin.. Skin is one of the largest organs of mammals; thus, it is often exposed to physical or chemical agents. This chapter provides an overview of the fundamental histopathologic lesions caused by chemicals, points out numerous similarities with lesions caused by other agents, and emphasizes the differences and peculiarities of the toxic reactions of skin. In addition, this chapter contains information on the pathophysiology of cutaneous toxic responses and suggests several approaches to evaluate and test for toxic effects in the integument. The oral mucosa is in many ways similar to the skin in its architecture, function, and reaction patterns. The chapter focuses on those characteristics of the oral mucosa that influence or result in a distinct group of pathologic entities. The oral mucosa is subjected to numerous natural and man-made xenobiotics because of its location at the entrance of the digestive and respiratory tract and its proximity to the teeth.

Publisher Summary Many of the features of the fish integument can only be observed microscopically. Because there are over 20,000 living fishes, mostly higher bony fishes (teleosts), a great diversity exists in the microscopic anatomy of the integument. This chapter presents several examples from varied taxonomic groups to illustrate the variation in morphological features. As in all vertebrate epidermis, the fundamental structural unit is the epithelial cell. This is the only constant feature, as a great diversity of cell types exists in the various fish taxa. Some of these include apocrine mucous cells and a variety of other secretory cells, ionocytes, sensory cells, and wandering cells such as leukocytes. The dermis consists essentially of two sets of collagen fibers arranged in opposing geodesic spirals around the body. The dermis of most fishes is divided into two major layers. The upper (outer) layer, the stratum spongiosum or stratum laxum, is a loose network of connective tissue, whereas the lower layer, the stratum compactum, is a dense layer consisting primarily of orthogonal collagen bands. There are also specialized dermal elements such as chromatophores scales, and fin rays.

Electron microprobe, which has not yet been used systematically in dermatological research, has already proved its immense value for qualitative and quantitative analysis. However, it is evident that rigorous preparation methods should be used to prevent the redistribution of diffusible elements, many of which are of crucial interest for understanding the origin of the pathological changes in the tissue. In areas outside routine general dermatological pathology, a further analytical tool is provided by the proton microprobe (PIXE analysis), which allows determination of trace elements, such as iron and zinc, as well as elements close to the lower range of detectability for X-ray microanalysis, for example, calcium and magnesium. Inexpensive analysis of bulk specimens such as hair fibers can be performed with the newly developed X-ray fluorescence technique (XRF), which has sensitivity comparable to that of PIXE. The probe size of XRF is generally not small enough to allow cellular and subcellular resolution, but ongoing development of the capillary focusing technique for X-rays now allows a beam cross section close to 5 μm. The fact remains that the door has just opened to the promising field of quantitative dermatology.

Publisher Summary The integument, the outer layer of the insect comprising the epidermis and the cuticle, is primarily responsible for the great success of insects as terrestrial animals. With regard to its rigidity and hardness, the cuticle not only supports the various body parts but also provides protection to the insect by restricting water loss and preventing invasion by foreign organisms. Hardened cuticle does not permit increase in body size or changes in forms therefore, insects during their life cycle, shed their old cuticle several times, and synthesize new ones that are soft and flexible initially to allow for expansion, but subsequently harden to a tough exoskeleton by a process known as tanning or sclerotization. Essentially, sclerotization protects eggs, egg cases, larval cuticle, pupal and puparial cuticle, and adult cuticle of insects. This chapter describes the recent advances in insect cuticular sclerotization. The three major mechanisms of cuticular sclerotization include: (1) Quinone tanning mechanism, (2) β -sclerotization, and (3) Quinone methide sclerotization. The discovery of quinine isomerase and quinone methide isomerase has resulted in the unification of these three different mechanisms into a single interlinked pathway.

Publisher Summary This chapter discusses cytophysiology of fish chromatophores, with emphasis on the chromatophores of class Osteichthyes. The chromatophores are responsible not only for the generation of color but also for changes in coloration of the surface coat. The beautiful colors and patterns and the spectacular changes in coloration is considered an important phenomena as it provides protection and assist in the survival of species in their habitats. Many poikilothermic aquatic animals, including fishes, use chromatic changes as a means of visual communication. The chapter highlights “physiological color changes,” which are the rapid changes caused by the motile activities of chromatophores. The absorption of light by the pigment in poikilothermic vertebrates is achieved by the light absorbing chromatophores, which include the melanophores, the erythrophores, and the xanthophores and also by the scattering and the reflection of light by intracellular structures, in the absence of colored materials, dependent on the presence in the skin of the light-reflecting chromatophores—namely, the leucophores and the iridophores. In the integument of fishes, pigment cells are found mostly in the dermis, where all the varieties of chromatophores can be located.

Publisher Summary This chapter discusses the sentiment that insects grow by molting. This sentiment constitutes the Central Dogma of Entomology. In one way or another, it has found its way into virtually all accounts of insect development. Because the cuticle is incapable of growth and, in the more rigid parts such as the head capsule or appendages, is incapable even of being stretched, it is shed from time to time as the insect grows, and a new and larger cuticle is laid down. The nonelastic nature of the arthropod cuticula gives the body wall but little tensibility. When the cuticula is formed, the integument can ordinarily increase in extent insofar as the wrinkles and folds of the cuticula straighten out. The ubiquity of the dogma is further illustrated by a quotation from the most influential treatise on applied entomology, which states that an insect does not grow by regular, gradual, and imperceptible degrees like a child, and therefore, growth inside this inexpansible shell cannot be regular and continuous. Though most insect growth occurs without molting, it is difficult to conceive of metamorphosis taking place that way.

Publisher Summary This chapter begins by discussing the evolution of barnacles and their shells. Later it exemplifies the mechanism of growth, modification of shape, and factors that influence growth rate in barnacles. As in most invertebrates, the rate of growth of juvenile barnacles at first accelerates, and then, with increasing age and maturity, slows down. Thus, whatever the initial growth rate, a given species tends toward the same ultimate size if allowed long enough to reach it. In seeking a more useful function by which to describe the change in growth with age, it must be borne in mind that the curve representing absolute growth will depend critically on the units employed, whether linear, superficial, or volumetric. The histology and fine structure of the integument are also discussed in this chapter. The importance of shell structure in relation to function is also highlighted. Shell growth in barnacles is usually measured as an increment over a given period of time, resulting from a series of influences, some endogenous, some exogenous. The factors that influence growth may act over a short or long term; they may operate only once or recur periodically. These are also considered and their magnitude is assessed.

Publisher Summary Receptors that signal the position of some part of an animal's body are usually organized in an opponent fashion. The activity of one population of receptors increases as the body part deviates progressively from some intermediate (rest) position toward one extreme of the range and the activity of another (the opponent) population of receptors decreases. The converse pattern of activity occurs when the body part deviates from the rest position in the opposite direction. This is the method whereby receptors signal the positions of joints, teeth, vibrissae, and the skin in mammals. Joint position in arthropods is also signalled in this fashion. In a few cases, one of the opponent receptor populations may be absent. Rarely has it been seen that individual receptors respond over only a limited portion of the range at intermediate positions. It is apparent, therefore, that position signalling with opponent populations is widely used by animals that are distantly related phylogenetically.

Publisher Summary This chapter describes the interaction of antifreeze glycopeptides and peptides with ice and water. All antifreezes affect the morphology or habit of ice crystals both at low and high concentrations. Crystal habit modification is observed with all glycopeptide antifreezes and with three different peptide antifreezes from three different species, which include the winter flounder, the shorthorn sculpin, and the sea raven. In the intact fish, antifreeze adsorption-inhibition of ice growth could occur at endogenous sites or at peripheral sites, such as the integument water interface. The composition and best available estimates of size for the antifreeze glycopeptides and peptides are given in a tabulated form in the chapter for several cold-water species. Fluids that lack antifreeze, such as urine and ocular fluids, appear to be protected in part from ice formation or the invasion of ice because the interstitial fluid within the tissues surrounding them contains antifreeze.