Review: Evolution and diversification of corneous beta‐proteins, the characteristic epidermal proteins of reptiles and birds

Holthaus, Karin Brigit; Eckhart, Leopold; Valle, Luisa Dalla; Alibardi, Lorenzo

doi:10.1002/jez.b.22840

Cited by 61 publications

(99 citation statements)

References 117 publications

(404 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In any event, a mature mesos layer characteristic of other snakes is not evident in this species (Figure ; see also Ripamonti et al, ). The above considerations potentially raise issues in terminology, which are beyond the scope and focus of the present study (see Holthaus et al, ).…”

Section: Discussionmentioning

confidence: 94%

“…Histologically, the skin of H. platurus displays the typical vertical layering of epidermal corneous proteins,conventionally termed βand α-keratin, that appear characteristic of squamates (Lillywhite & Maderson, 1982). Recent review of keratinization and cornification of the reptilian epidermis (Alibardi, 2016;Calvaresi, Eckhart, & Alibardi, 2016;Holthaus, Eckhart, Valle, & Alibardi, 2019) makes clear distinction between these two processes, as the terminal differentiation of keratinizing cells involves addition of several gene products that are not related to keratin genes, but derive from a region of a chromosome indicated as Epidermal Differentiation Complex (EDC; Mischke, Korge, Marenholz, Volz, & Ziegler, 1996). It was suggested that the erstwhile β-keratin be reclassified as EDC corneous proteins, and the alpha keratins as Intermediate Filament (IF) keratins, which is compatible with a molecular-biological and protein-analytical point of view (Alibardi, 2016).…”

Section: Ultrastructural Featuresmentioning

confidence: 99%

See 1 more Smart Citation

Structure and function of skin in the pelagic sea snake, Hydrophis platurus

Lillywhite

Menon

2019

Journal of Morphology

View full text Add to dashboard Cite

We describe and interpret the functional morphology of skin of the Yellow‐bellied sea snake, Hydrophis platurus. This is the only pelagic sea snake, and its integument differs from what is known for other species of snakes. In gross appearance, the scales of H. platurus consist of non‐overlapping, polygonal knobs with flattened outer surfaces bearing presumptive filamentous sensillae. The deep recesses between scales (‘hinge’) entrap and wick water over the body surface, with mean retention of 5.1 g/cm of skin surface, similar to that determined previously for the roughened, spiny skin of marine file snakes, Acrochordus granulatus. This feature possibly serves to maintain the skin wet when the dorsal body protrudes above water while floating on calm oceanic slicks where they forage. In contrast with other snakes, including three species of amphibious, semi‐marine sea kraits (Laticauda spp.), the outer corneous β‐protein layer consists of a syncytium that is thinner than seen in most other species. The subjacent α‐layer is also thin, and lipid droplets and lamellar bodies are seen among the immature, cornifying α‐cells. A characteristic mesos layer, comprising the water permeability barrier, is either absent or very thin. These features are possibly related to (1) permeability requirements for cutaneous gas exchange, (2) reduced gradient for water efflux compared with terrestrial environments, (3) less need for physical protection in water compared with terrestrial ground environments, and (4) increased frequency of ecdysis thought to be an anti‐fouling mechanism. The lipogenic features of the α‐layer possibly compensate for the reduced or absent mesos layer, or produce layers of cells that comprise what functionally might be termed a mesos layer, but where the organization of barrier lipids nonetheless appears less robust than what is characteristically seen in squamates.

show abstract

Section: Discussionmentioning

confidence: 94%

Section: Ultrastructural Featuresmentioning

confidence: 99%

Structure and function of skin in the pelagic sea snake, Hydrophis platurus

Lillywhite

Menon

2019

Journal of Morphology

View full text Add to dashboard Cite

show abstract

“…CBP genes are located in a single locus in lizards and in one main locus and in a few additional loci in birds and reptiles (Dalla Valle et al, ; Gregg & Rogers, ). Translocation of some CBP genes from the EDC locus in birds and turtles revealed its relationship to the formation of appendages, such as feather and carapaces (Holthaus et al, , Holtahus, Eckhart, Dalla Valle & Alinardi, . However, loci with genes encoding alpha‐keratin are distant and unrelated phylogenetically with CBP genes (Holthaus et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Alpha‐keratin and corneous beta protein in the parakeratinized epithelium of the tongue in the domestic goose (Anser anser f. domestica)

et al. 2019

View full text Add to dashboard Cite

The parakeratinized epithelium is a common epithelium in the oral cavity in birds and is characterized by the presence of cell nuclei in the cells of the cornified layer. This epithelium covers almost the entire dorsal surface of the tongue in the domestic goose apart of the lingual nail and conical papillae. So far no study has identified the molecular proteins alpha-keratin (IF-keratin) and/or corneous beta protein (CBP), which are responsible for keratinization or cornification processes in the parakeratinized epithelium of domestic geese. The study was performed using immunohistochemical (IHC) methods to identify alpha-keratin. The innovative method of Raman microspectroscopy was used to determine the presence of CBP and specify their percentage in epithelial layers of the parakeratinized epithelium.The results revealed that alpha-keratin is present in the whole parakeratinized epithelium. A strong staining reaction was detected in the basal and intermediate layers and a less strong staining reaction in the cornified layer. Raman microspectroscopy analysis confirmed the presence of alpha-keratin and demonstrated that its percentage decreases from the basal layer to the cornified layer. The Raman microspectroscopy technique revealed the occurrence of CBP in the parakeratinized epithelium and demonstrated that the percentage of this protein increases from the basal layer to the cornified layer. Performed analysis determines that parakeratinized epithelium undergoes cornification. However, the lower percentage of CBP in the cornified layer of parakeratinized epithelium than in orthokeratinized epithelium points to the fact that parakeratinized epithelium has a weaker protective function.

show abstract

“…Although the different feather types vary considerably in their fine structure, they show a Handling Editor: Georg Krohne Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00709-020-01544-7) contains supplementary material, which is available to authorized users. surprisingly uniform molecular composition mainly of a specific protein formerly considered as beta-keratin of the avian family, now named corneous beta-protein (CBP; Holthaus et al 2018). The specific supramolecular arrangement of CBPs provides feathers with the necessary stiffness and the indispensible elasticity both of which are essential for the role of feathers in bird flight and the various other feather functions (Greenwold and Sawyer 2011).…”

Section: Introductionmentioning

confidence: 99%

Detection of endogenous lipids in chicken feathers distinct from preen gland constituents

Zeisler‐Diehl

Al-Khutabi

Kirfel³

et al. 2020

Protoplasma

View full text Add to dashboard Cite

Bird feather lipids are usually attributed to the oily secretion product of the uropygial (preen) gland. We have observed, however, that feathers exhibit a strong reaction with osmium tetroxide (OsO4), even after treatment with detergents. This leads us to postulate the existence of endogenous feather lipids distinct from preen gland lipids. In order to substantiate our hypothesis, we investigated down feathers from a 1-day-old chicken as their uropgygial gland is not functionally active. The results confirmed the osmiophilic reaction, which was concentrated in the center of barbs and strongly reduced after lipid extraction. In these lipid extracts, we identified using thin layer chromatography, cholesterol, various ceramides, glycolipids, phospholipids, and fatty acids, which closely resembled the lipid composition of the water barrier in the chicken-cornified epidermal envelope. This composition is clearly distinct from chicken uropygeal gland secretion (UGS) known to consist of fatty alcohols as part of aliphatic monoester waxes and of free, predominantly saturated, fatty acids. A filter assay showed a strong reactivity between OsO4 and the fatty acids C18:1 and C18:2 and with feather lipid extracts, but not with UGS. These observations were confirmed by gas chromatography detecting unsaturated fatty acids including C18:1 and C18:2 as well as cholesterol exclusively in chicken feathers. Our results indicate that (1) endogenous lipids are detectable in chicken feathers and distinct from UGS and (2) in analogy to the morphogenesis of the cornified envelope of chicken feather lipids that may have derived from cellular feather-precursors, apparently enduring the specific cell death during developmental feather cornification.

show abstract

Review: Evolution and diversification of corneous beta‐proteins, the characteristic epidermal proteins of reptiles and birds

Cited by 61 publications

References 117 publications

Structure and function of skin in the pelagic sea snake, Hydrophis platurus

Structure and function of skin in the pelagic sea snake, Hydrophis platurus

Alpha‐keratin and corneous beta protein in the parakeratinized epithelium of the tongue in the domestic goose (Anser anser f. domestica)

Detection of endogenous lipids in chicken feathers distinct from preen gland constituents

Contact Info

Product

Resources

About