Feathers
Psittaciformes
beta-Keratins
Parrots
Molting
Beak
Bird Diseases
Integumentary System
Passeriformes
Dinosaurs
Color
Fossils
Chick Embryo
Phthiraptera
Songbirds
Earth Sciences
Struthioniformes
Books
Embryonal feather growth in the chicken. (1/576)
Prenatal feather growth development in the chicken was studied in 7 body regions in HH stages 27-45, using direct measurements, specific histological and immunohistochemical methods, and scanning electron microscopy. The results from measurements of absolute length values, and, particularly, growth rate development in each HH stage revealed a distinct phase of most intensive growth in HH stage 40-41, which was preceded by feather follicle insertion and accompanied by the occurrence of alpha-keratins in barbule cells. Specific regional evaluation demonstrated that growth in the feather follicles of abdominal skin generally showed the slowest progression from absolute values and that in the feather filaments of the developing wings the most rapid progression occurred during HH stage 40-41 from growth rate values. (+info)Role of Pitx1 upstream of Tbx4 in specification of hindlimb identity. (2/576)
In spite of recent breakthroughs in understanding limb patterning, the genetic factors determining the differences between the forelimb and the hindlimb have not been understood. The genes Pitx1 and Tbx4 encode transcription factors that are expressed throughout the developing hindlimb but not forelimb buds. Misexpression of Pitx1 in the chick wing bud induced distal expression of Tbx4, as well as HoxC10 and HoxC11, which are normally restricted to hindlimb expression domains. Wing buds in which Pitx1 was misexpressed developed into limbs with some morphological characteristics of hindlimbs: the flexure was altered to that normally observed in legs, the digits were more toe-like in their relative size and shape, and the muscle pattern was transformed to that of a leg. (+info)Wnt-7a in feather morphogenesis: involvement of anterior-posterior asymmetry and proximal-distal elongation demonstrated with an in vitro reconstitution model. (3/576)
How do vertebrate epithelial appendages form from the flat epithelia? Following the formation of feather placodes, the previously radially symmetrical primordia become anterior-posterior (A-P) asymmetrical and develop a proximo-distal (P-D) axis. Analysis of the molecular heterogeneity revealed a surprising parallel of molecular profiles in the A-P feather buds and the ventral-dorsal (V-D) Drosophila appendage imaginal discs. The functional significance was tested with an in vitro feather reconstitution model. Wnt-7a expression initiated all over the feather tract epithelium, intensifying as it became restricted first to the primordia domain, then to an accentuated ring pattern within the primordia border, and finally to the posterior bud. In contrast, sonic hedgehog expression was induced later as a dot within the primordia. RCAS was used to overexpress Wnt-7a in reconstituted feather explants derived from stage 29 dorsal skin to further test its function in feather formation. Control skin formed normal elongated, slender buds with A-P orientation, but Wnt-7a overexpression led to plateau-like skin appendages lacking an A-P axis. Feathers in the Wnt-7a overexpressing skin also had inhibited elongation of the P-D axes. This was not due to a lack of cell proliferation, which actually was increased although randomly distributed. While morphogenesis was perturbed, differentiation proceeded as indicated by the formation of barb ridges. Wnt-7a buds have reduced expression of anterior (Tenascin) bud markers. Middle (Notch-1) and posterior bud markers including Delta-1 and Serrate-1 were diffusely expressed. The results showed that ectopic Wnt-7a expression enhanced properties characteristic of the middle and posterior feather buds and suggest that P-D elongation of vertebrate skin appendages requires balanced interactions between the anterior and posterior buds. (+info)Purification and characterization of a keratinolytic serine proteinase from Streptomyces albidoflavus. (4/576)
Streptomyces strain K1-02, which was identified as a strain of Streptomyces albidoflavus, secreted at least six extracellular proteases when it was cultured on feather meal-based medium. The major keratinolytic serine proteinase was purified to homogeneity by a two-step procedure. This enzyme had a molecular weight of 18,000 and was optimally active at pH values ranging from 6 to 9.5 and at temperatures ranging from 40 to 70 degrees C. Its sensitivity to protease inhibitors, its specificity on synthetic substrates, and its remarkably high level of NH2-terminal sequence homology with Streptomyces griseus protease B (SGPB) showed that the new enzyme, designated SAKase, was homologous to SGPB. We tested the activity of SAKase with soluble and fibrous substrates (elastin, keratin, and type I collagen) and found that it was very specific for keratinous substrates compared to SGPB and proteinase K. (+info)Influence of drinking water and diet on the stable-hydrogen isotope ratios of animal tissues. (5/576)
Despite considerable interest in using stable-hydrogen isotope ratio (deltaD) measurements in ecological research, it was previously unknown whether hydrogen derived from drinking water, in addition to that derived from diet, contributed to the nonexchangeable hydrogen in animal tissues. We raised four experimental groups of quail (Coturnix coturnix japonica) from hatch on two isotopically distinct diets (mean nonexchangeable deltaD: -146 and -60 per thousand, Vienna Standard Mean Ocean Water Standard) and drinking waters (mean deltaD: -130 and +196 per thousand, Vienna Standard Mean Ocean Water Standard). Here we show that both dietary and drinking water hydrogen are incorporated into nonexchangeable hydrogen in both metabolically active (i.e., muscle, liver, blood, fat) and inactive (i.e., feather, nail) tissues. Approximately 20% of hydrogen in metabolically active quail tissues and 26-32% of feathers and nail was derived from drinking water. Our findings suggest environmental interpretations of deltaD values from modern and fossil animal tissues may need to account for potentially large isotopic differences between drinking water and food and require a good understanding of the physiological ecology of study organisms. (+info)Carotenoids, sexual signals and immune function in barn swallows from Chernobyl. (6/576)
Carotenoids have been hypothesized to facilitate immune function and act as free-radical scavengers, thereby minimizing the frequency of mutations. Populations of animals exposed to higher levels of free radicals are thus expected to demonstrate reduced sexual coloration if use of carotenoids for free-radical scavenging is traded against use for sexual signals. The intensity of carotenoid-based sexual coloration was compared among three populations of barn swallows Hirundo rustica differing in exposure to radioactive contamination. Lymphocyte and immunoglobulin concentrations were depressed, whereas the heterophil:lymphocyte ratio, an index of stress, was enhanced in Chernobyl swallows compared to controls. Spleen size was reduced in Chernobyl compared to that of two control populations. Sexual coloration varied significantly among populations, with the size of a secondary sexual character (the length of the outermost tail feathers) being positively related to coloration in the two control populations, but not in the Chernobyl population. Thus the positive covariation between coloration and sexual signalling disappeared in the population subject to intense radioactive contamination. These findings suggest that the reliable signalling function of secondary sexual characters breaks down under extreme environmental conditions, no longer providing reliable information about the health status of males. (+info)beta-catenin signaling can initiate feather bud development. (7/576)
Intercellular signaling by a subset of Wnts is mediated by stabilization of cytoplasmic beta-catenin and its translocation to the nucleus. Immunolocalization of beta-catenin in developing chick skin reveals that this signaling pathway is active in a dynamic pattern from the earliest stages of feather bud development. Forced activation of this pathway by expression of a stabilized beta-catenin in the ectoderm results in the ectopic formation of feather buds. This construct is sufficient to induce bud formation since it does so both within presumptive feather tracts and in normally featherless regions where tract-specific signals are absent. It is also insensitive to the lateral inhibition that mediates the normal spacing of buds and can induce ectopic buds in interfollicular skin. However, additional patterning signals cooperate with this pathway to regulate gene expression within domains of stabilized beta-catenin expression. Localized activation of this pathway within the bud as it develops is required for normal morphogenesis and ectopic activation of the pathway leads to abnormally oriented buds and growths on the feather filaments. These results suggest that activation of the beta-catenin pathway initiates follicle development in embryonic skin and plays important roles in the subsequent morphogenesis of the bud. (+info)The role of long range, local and direct signalling molecules during chick feather bud development involving the BMPs, follistatin and the Eph receptor tyrosine kinase Eph-A4. (8/576)
The development of the feather buds during avian embryogenesis is a classic example of a spacing pattern. The regular arrangement of feather buds is achieved by a process of lateral inhibition whereby one developing feather bud prevents the formation of similar buds in the immediate vicinity. Lateral inhibition during feather formation implicates a role of long range signalling during this process. Recent work has shown that BMPs are able to enforce lateral inhibition during feather bud formation. However these results do not explain how the feather bud escapes the inhibition itself. We show that this could be achieved by the expression of the BMP antagonist, Follistatin. Furthermore we show that local application of Follistatin leads to the development of ectopic feather buds. We suggest that Follistatin locally antagonises the action of the BMPs and so permits the cellular changes associated with feather placode formation. We also provide evidence for the role of short range signalling during feather formation. We have correlated changes in cellular morphology in feather placodes with the expression of the gene Eph-A4 which encodes a receptor tyrosine kinase that requires direct cell-cell contact for activation. We show that the expression of this gene precedes cellular reorganisation required for feather bud formation. (+info)Feathers are not a medical term, but they are a feature found in birds and some extinct theropod dinosaurs. Feathers are keratinous structures that grow from the skin and are used for various functions such as insulation, flight, waterproofing, and display. They have a complex structure consisting of a central shaft with barbs branching off on either side, which further divide into smaller barbules. The arrangement and modification of these feather structures vary widely among bird species to serve different purposes.
Psittaciformes is not a medical term but a taxonomic order that includes parrots, cockatoos, and related species. However, in a medical context, "psittacosis" is a relevant term that can be discussed.
Psittacosis is a zoonotic disease caused by the bacterium Chlamydia psittaci, which can infect humans through contact with infected birds or their droppings. The disease is also known as parrot fever or ornithosis. Psittacosis can cause flu-like symptoms in humans, such as fever, headache, muscle aches, and cough. In severe cases, it can lead to pneumonia and other complications.
Therefore, while "Psittaciformes" is not a medical term itself, the order includes many bird species that can carry and transmit Chlamydia psittaci, leading to the disease known as psittacosis in humans.
Beta-keratins are a type of keratin proteins that are mainly found in the cells of reptiles, birds, and some mammals such as marsupials. These proteins make up the scales, feathers, claws, beaks, and other hard structures of these animals. Beta-keratins have a different molecular structure compared to alpha-keratins, which are the predominant type of keratins found in mammalian skin, hair, and nails.
I am not aware of a medical definition for the term "birds." Birds are a group of warm-blooded vertebrates constituting the class Aves, characterized by feathers, toothless beaked jaws, the laying of hard-shelled eggs, and lightweight but strong skeletons. Some birds, such as pigeons and chickens, have been used in medical research, but the term "birds" itself does not have a specific medical definition.
I'm sorry for any confusion, but "Parrots" is not a medical term. It is a common name used to refer to a group of birds that are known for their ability to mimic human speech. If you have any questions about medical terminology or health-related topics, I would be happy to try and help answer them for you!
"Molting" is not a term typically used in medical contexts. It is primarily used to describe the shedding and replacement of feathers, hair, or skin in animals, including birds, reptiles, insects, and other invertebrates. In humans and other mammals, this process is more commonly referred to as "shedding" or "growing new hair/skin."
However, if you are referring to the medical term "molt," it is a rare genetic disorder that affects the skin's pigmentation and causes it to shed in patches. It is also known as "congenital ichthyosiform erythroderma" or "non-bullous congenital ichthyosiform erythroderma." The condition is present at birth, and affected individuals have red, scaly skin that sheds in a pattern similar to snake skin. Molting is not contagious and has no known cure, but various treatments can help manage its symptoms.
In medical terms, "beak" is not a term that is used as a general definition or diagnosis. However, there are some specific medical contexts where the term "beak" is used:
1. In forensic medicine, "beak" refers to the pointed end of a broken bone, which can occur when a bone is fractured in a certain way.
2. In respiratory medicine, "beaked nose" is a colloquial term used to describe a nose with a sharply pointed tip.
3. In maxillofacial surgery, "beak deformity" is a rare condition where the upper jaw protrudes excessively, giving the appearance of a bird's beak.
4. In veterinary medicine, "beak trimming" refers to the practice of trimming the beaks of birds to prevent them from injuring themselves or others.
It's important to note that these are very specific medical contexts and may not be relevant to your search for a general medical definition of "beak."
'Bird diseases' is a broad term that refers to the various medical conditions and infections that can affect avian species. These diseases can be caused by bacteria, viruses, fungi, parasites, or toxic substances and can affect pet birds, wild birds, and poultry. Some common bird diseases include:
1. Avian influenza (bird flu) - a viral infection that can cause respiratory symptoms, decreased appetite, and sudden death in birds.
2. Psittacosis (parrot fever) - a bacterial infection that can cause respiratory symptoms, fever, and lethargy in birds and humans who come into contact with them.
3. Aspergillosis - a fungal infection that can cause respiratory symptoms and weight loss in birds.
4. Candidiasis (thrush) - a fungal infection that can affect the mouth, crop, and other parts of the digestive system in birds.
5. Newcastle disease - a viral infection that can cause respiratory symptoms, neurological signs, and decreased egg production in birds.
6. Salmonellosis - a bacterial infection that can cause diarrhea, lethargy, and decreased appetite in birds and humans who come into contact with them.
7. Trichomoniasis - a parasitic infection that can affect the mouth, crop, and digestive system in birds.
8. Chlamydiosis (psittacosis) - a bacterial infection that can cause respiratory symptoms, lethargy, and decreased appetite in birds and humans who come into contact with them.
9. Coccidiosis - a parasitic infection that can affect the digestive system in birds.
10. Mycobacteriosis (avian tuberculosis) - a bacterial infection that can cause chronic weight loss, respiratory symptoms, and skin lesions in birds.
It is important to note that some bird diseases can be transmitted to humans and other animals, so it is essential to practice good hygiene when handling birds or their droppings. If you suspect your bird may be sick, it is best to consult with a veterinarian who specializes in avian medicine.
The integumentary system is the largest organ system in the human body, encompassing the skin, hair, nails, and various glands. Its primary function is to act as a barrier, protecting the body from external damage, radiation, and pathogens while also helping regulate body temperature, prevent water loss, and maintain fluid balance. The integumentary system plays crucial roles in sensory perception through nerve endings in the skin, synthesizing vitamin D via sunlight exposure, and excreting waste products through sweat. Overall, it serves as a vital organ system that ensures the body's integrity and homeostasis.
Pigmentation, in a medical context, refers to the coloring of the skin, hair, or eyes due to the presence of pigment-producing cells called melanocytes. These cells produce a pigment called melanin, which determines the color of our skin, hair, and eyes.
There are two main types of melanin: eumelanin and pheomelanin. Eumelanin is responsible for brown or black coloration, while pheomelanin produces a red or yellow hue. The amount and type of melanin produced by melanocytes can vary from person to person, leading to differences in skin color and hair color.
Changes in pigmentation can occur due to various factors such as genetics, exposure to sunlight, hormonal changes, inflammation, or certain medical conditions. For example, hyperpigmentation refers to an excess production of melanin that results in darkened patches on the skin, while hypopigmentation is a condition where there is a decreased production of melanin leading to lighter or white patches on the skin.
I'm sorry for any confusion, but "Passeriformes" is not a medical term. It is a taxonomic category in biology, specifically an order of birds that includes over half of all bird species. Passeriformes are often referred to as perching birds or songbirds because many of them have specialized feet for perching on branches and a wide variety of vocalization capabilities. Examples of Passeriformes include sparrows, finches, robins, and crows.
Dinosaurs are a group of reptiles that were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous period. They first appeared approximately 230 million years ago and went extinct around 65 million years ago.
Dinosaurs are characterized by their upright stance, with legs positioned directly under their bodies, and a wide range of body sizes and shapes. Some dinosaurs were enormous, such as the long-necked sauropods that could reach lengths of over 100 feet, while others were small and agile.
Dinosaurs are classified into two main groups: the saurischians (lizard-hipped) and the ornithischians (bird-hipped). The saurischians include both the large carnivorous theropods, such as Tyrannosaurus rex, and the long-necked sauropods. The ornithischians were primarily herbivores and included a diverse array of species, such as the armored ankylosaurs and the horned ceratopsians.
Despite their extinction, dinosaurs have left a lasting impact on our planet and continue to be a source of fascination for people of all ages. The study of dinosaurs, known as paleontology, has shed light on many aspects of Earth's history and the evolution of life on our planet.
In the context of medical terminology, 'color' is not defined specifically with a unique meaning. Instead, it generally refers to the characteristic or appearance of something, particularly in relation to the color that a person may observe visually. For instance, doctors may describe the color of a patient's skin, eyes, hair, or bodily fluids to help diagnose medical conditions or monitor their progression.
For example, jaundice is a yellowing of the skin and whites of the eyes that can indicate liver problems, while cyanosis refers to a bluish discoloration of the skin and mucous membranes due to insufficient oxygen in the blood. Similarly, doctors may describe the color of stool or urine to help diagnose digestive or kidney issues.
Therefore, 'color' is not a medical term with a specific definition but rather a general term used to describe various visual characteristics of the body and bodily fluids that can provide important diagnostic clues for healthcare professionals.
In medical terms, "fossils" do not have a specific or direct relevance to the field. However, in a broader scientific context, fossils are the remains or impressions of prehistoric organisms preserved in petrified form or as a mold or cast in rock. They offer valuable evidence about the Earth's history and the life forms that existed on it millions of years ago.
Paleopathology is a subfield of paleontology that deals with the study of diseases in fossils, which can provide insights into the evolution of diseases and human health over time.
A chick embryo refers to the developing organism that arises from a fertilized chicken egg. It is often used as a model system in biological research, particularly during the stages of development when many of its organs and systems are forming and can be easily observed and manipulated. The study of chick embryos has contributed significantly to our understanding of various aspects of developmental biology, including gastrulation, neurulation, organogenesis, and pattern formation. Researchers may use various techniques to observe and manipulate the chick embryo, such as surgical alterations, cell labeling, and exposure to drugs or other agents.
"Animal Flight" is not a medical term per se, but it is a concept that is studied in the field of comparative physiology and biomechanics, which are disciplines related to medicine. Animal flight refers to the ability of certain animal species to move through the air by flapping their wings or other appendages. This mode of locomotion is most commonly associated with birds, bats, and insects, but some mammals such as flying squirrels and sugar gliders are also capable of gliding through the air.
The study of animal flight involves understanding the biomechanics of how animals generate lift and propulsion, as well as the physiological adaptations that allow them to sustain flight. For example, birds have lightweight skeletons and powerful chest muscles that enable them to flap their wings rapidly and generate lift. Bats, on the other hand, use a more complex system of membranes and joints to manipulate their wings and achieve maneuverability in flight.
Understanding animal flight has important implications for the design of aircraft and other engineering systems, as well as for our broader understanding of how animals have evolved to adapt to their environments.
Phthiraptera is an order of small parasitic insects, also known as lice. They are characterized by having a specialized body structure adapted for living in close association with birds and mammals. There are three main subgroups: Anoplura (sucking lice), Ischnocera (chewing lice), and Rhynchophthirina (large-biting lice). Lice can cause itching, discomfort, and spread diseases to their hosts.
I believe there may be some confusion in your question as "Songbirds" is a common name given to a group of birds known for their vocal abilities, rather than a term used in medical definitions. Songbirds, also known as passerines, are a diverse group of more than 5,000 species of small to medium-sized birds. They belong to the order Passeriformes and include familiar birds such as sparrows, finches, robins, and warblers.
If you have any questions related to medical terminology or healthcare topics, please let me know and I would be happy to help!
The Earth sciences are a group of academic disciplines that focus on the scientific study of the Earth, its systems, processes, and phenomena. This encompasses a wide range of fields, including geology, physics, chemistry, biology, and mathematics. The Earth sciences seek to understand the Earth's internal structure, composition, and dynamics, as well as its surface processes, climate, and environmental changes over time.
Some specific areas within the Earth sciences include:
1. Geology: the study of the solid Earth, including its rocks, minerals, and structures.
2. Geophysics: the application of physics to the study of the Earth, including its internal structure, dynamics, and magnetic fields.
3. Geochemistry: the study of the chemical composition and processes of the Earth's materials, such as rocks, minerals, and fluids.
4. Paleontology: the study of ancient life forms, including fossils and their environments.
5. Meteorology: the study of the atmosphere, weather patterns, and climate.
6. Oceanography: the study of the oceans, including their physical properties, chemistry, biology, and geology.
7. Environmental science: the interdisciplinary study of environmental systems, including their natural and human-induced changes.
Overall, the Earth sciences provide valuable insights into the complex interactions between the Earth's various systems and how they have evolved over time. This knowledge is essential for understanding our planet's past, present, and future, as well as for developing strategies to mitigate natural hazards and protect its resources.
Paleontology is not a medical field, but rather it is a branch of earth sciences and biology that deals with the study of prehistoric life forms through the examination of plant and animal fossils, including those of extinct organisms. It involves various disciplines such as stratigraphy, geochronology, and systematics to understand the evolutionary history of life on Earth.
However, I understand that you are looking for information related to a non-medical topic, so here is some additional context:
Paleontology can be divided into several subdisciplines, including vertebrate paleontology (the study of fossilized animals with backbones), invertebrate paleontology (the study of fossilized animals without backbones), paleobotany (the study of fossil plants), micropaleontology (the study of microscopic fossils), and taphonomy (the study of the processes that occur after an organism's death, leading to its preservation as a fossil).
Paleontologists use various techniques to study fossils, including comparative anatomy, histology (the study of tissue structure), and geochemistry. They also rely on other scientific fields such as genetics, physics, and chemistry to help them interpret the data they collect from fossils.
Through their research, paleontologists can learn about the morphology, behavior, ecology, and evolutionary relationships of extinct organisms, providing valuable insights into the history of life on Earth.
Struthioniformes is an order of large, flightless birds that includes ostriches, emus, cassowaries, and rheas. These birds are characterized by their inability to fly, long necks, and strong legs adapted for running. They are found in various parts of the world, with ostriches native to Africa, emus to Australia, cassowaries to Indonesia and Papua New Guinea, and rheas to South America. Struthioniformes birds are known for their fast running speed, with the ostrich being the fastest bird on land, capable of reaching speeds up to 60 miles per hour. They also lay large, hard-shelled eggs that are among the largest in the animal kingdom.
I apologize for any confusion, but "books" is a general term that refers to bound sets of pages that are printed or written with text, illustrations, or signs, and are meant to be read, studied, or consulted. It does not have a specific medical definition. If you're looking for information about a specific medical term or concept, please let me know and I'd be happy to help!