The developmental basis of morphological complexity remains a central question in developmental and evolutionary biology. Feathers provide a unique system to analyze the development of complex morphological novelties. Here, we describe the interactions between Sonic hedgehog (Shh) and bone morphogenetic protein 2 (Bmp2) signaling during feather barb ridge morphogenesis. We demonstrate that acti...

BACKGROUND An association study between single nucleotide polymorphism markers (SNP) and (innate and adaptive) immune parameters but also feather condition score on the back, rump and belly of laying hens was performed. The immune parameters measured in blood samples were natural and acquired antibody titers and complement activity. Feather condition score as a measure of feather damage was det...

backgrounds and objectives:today, one of the most important environmental issues is solid waste produced in dentistry that because of the presence of hazardous, toxic and pathogen agents has special importance. in this survey, solid waste produced in hamadan dentistry laboratories and practical dentist offices is studied.materials and methods: in this descriptive study, from 24 dentistry labora...

Asymmetry in flight feather vane width is a major functional innovation associated with the evolution of flight in the ancestors of birds. However, the developmental and morphological basis of feather shape is not simple, and the developmental processes involved in vane width asymmetry are poorly understood. We present a theoretical model of feather morphology and development that describes the...

In nest-bound avian offspring, food shortages typically trigger a release of the stress hormone corticosterone (CORT). Recent studies indicate that CORT is passively deposited in the tissue of growing feathers and thus may provide an integrated measure of stress incurred during development in the nest. The current hypothesis predicts that, assuming a constant rate of feather growth, elevated CO...

The bird feather vane can be separated into two parts by pulling the barbs apart. The original state can be re-established easily by lightly stroking through the feather. Hooklets responsible for holding vane barbs together are not damaged by multiple zipping and unzipping cycles. Because numerous microhooks keep the integrity of the feather, their properties are of great interest for understan...

In this study,mean shift algorithm and region merging were combined to automatically segment a digital feather image and remove the noise in digital images more effectively for segmentation of a feather quill and a feather leaf. First, the mean shift algorithm employed to calculate the convergence value of each pixel can obtain a filtered smoothened image; then, setting region merging criteria ...

A comparative study of feather morphogenesis and the development of feather pattern in normal and talpid embryos has been carried out. The development of talpid* CAM grafts shows that the effect of the gene is autonomous in the skin. The most striking effect of the gene upon feather morphogenesis is the failure of normal feather germ condensations to appear within the dermis. This is reflected ...

We present the first explicit theory of the growth of feather shape, defined as the outline of a pennaceous feather vane. Based on a reanalysis of data from the literature, we propose that the absolute growth rate of the barbs and rachis ridges, not the vertical growth rate, is uniform throughout the follicle. The growth of feathers is simulated with a mathematical model based on six growth par...

Feather keratin is highly resistant to degradation, but some keratinase producing microorganisms can easily degrade these insoluble keratins. These keratinase producing species have an important application in removal of poultry waste and recycled into valuable byproduct. A feather-degrading bacterium with high keratinase activity was isolated and identified as Bacillus megaterium (A1). The sel...