A review of terrestrial, aerial and aquatic keratins: the structure and mechanical properties of pangolin scales, feather shafts and baleen plates

Wang, Bin; Sullivan, Tarah N.

doi:10.1016/j.jmbbm.2017.05.015

Cited by 28 publications

(14 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Keratin is highly prevalent in animal coverings, including feathers, hair, scales, and nails [3,4]. Further, the crude protein content of keratin waste is more than 85%, which is a very attractive protein reserve; however, recycling of this product poses problems that are similar to those in case of cellulose [5]. Keratin materials, divided into α-keratin and β-keratin, contain a large number of disulfide bonds, hydrogen bonds, and hydrophobic interactions, which are difficult to decompose [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Biotransformation of keratin waste to amino acids and active peptides based on cell-free catalysis

Peng

Mao

Zhang

et al. 2020

Biotechnol Biofuels

View full text Add to dashboard Cite

Background: Keratin is the primary constituent of the vertebrate epidermis and epidermal appendages, as well as the main waste product generated during poultry processing from feathers, hair, scales, nails, etc. Keratin is generally hard, stubborn and difficult to hydrolyze; however, it is also inexpensive and contains more than 85% protein. Currently, tens of millions of tons of keratin waste are produced each year worldwide; however, no effective methods for the recovery of keratin waste have been reported thus far, making such research urgent. Keratinase has been reported to be useful for keratin waste recovery; however, nearly all keratinases are unable to hydrolyze keratin after they are detached from living cell systems. This may be due to low keratinase activity and lack of synergistic factors. Results: Herein, the keratinase gene from Bacillus licheniformis BBE11-1 was successfully expressed in Bacillus subtilis WB600, allowing for improved activity of the recombinant keratinase KerZ1 to 45.14 KU/mL via promoter substitution and screening of the ribosome-binding sites. Further, real-time control of temperature, pH, dissolved oxygen, and feed strategy allowed the activity of KerZ1 to reach 426.60 KU/mL in a 15-L fermenter, accounting for a 3552-fold increase compared to the wild-type keratinase (120.1 U/mL). Most importantly, we proposed a method based on the synergistic action of keratinase KerZ1 and sodium sulfite, to hydrolyze feathers into amino acids. In specific, 100 g/L of feather waste can be successfully converted into 56.6% amino acids within 12 h, while supporting the production of dozens of bioactive peptides. Conclusions: The activity of recombinant keratinase can be greatly enhanced via transcription and translational regulation in Bacillus subtilis. The synergistic action of keratinase and sulfite can rapidly degrade feather waste and produce amino acids and polypeptides.

show abstract

Section: Introductionmentioning

confidence: 99%

Biotransformation of keratin waste to amino acids and active peptides based on cell-free catalysis

Peng

Mao

Zhang

et al. 2020

Biotechnol Biofuels

View full text Add to dashboard Cite

show abstract

“…Pangolin scales, which are soft on newborn pangolins but harden as the animals mature, are formed by keratins 8 , guaranteeing a high abrasive wear resistance 9 . Apparently, the scales of pangolins are better able to help organisms in their physical defence, protecting them from predators 10 . Springer and Gatesy (2018) found that the mutation or deletion of MC5R gene related to sebaceous gland development was an important molecular affecting the unusual skin characteristics of pangolin 11 , and even the evolution of scales on their backs is thought to have compensated for the lower body immunity 7 .…”

Section: Introductionmentioning

confidence: 99%

Combined proteomics and transcriptomics reveal the genetic basis underlying the differentiation of skin appendages and immunity in pangolin

Liu

Zhang

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Pangolin ( Mains javanica ) is an interesting endangered mammal with special morphological characteristics. Here, we applied proteomics and transcriptomics to explore the differentiation of pangolin skin appendages at two developmental stages and to compare gene expression profiles between abdomen hair and dorsal scale tissues. We identified 4,311 genes and 91 proteins differentially expressed between scale-type and hair-type tissue, of which 6 genes were shared by the transcriptome and proteome. Differentiation altered the abundance of hundreds of proteins and mRNA in the two types of skin appendages, many of which are involved in keratinocyte differentiation, epidermal cell differentiation, and multicellular organism development based on GO enrichment analysis, and FoxO, MAPK, and p53 signalling pathways based on KEGG enrichment analysis. DEGs in scale-type tissues were also significantly enriched in immune-related terms and pathways compared with that in hair-type tissues. Thus, we propose that pangolins have a normal skin innate immune system. Compared with the abdomen, the back skin of pangolins had more genes involved in the regulation of immune function, which may be an adaptive adjustment for the vulnerability of scaly skin to infection and injury. This investigation provides a scientific basis for the study of development and immunity of pangolin skin, which may be helpful in the protection of wild pangolin in China.

show abstract

“…Geometrical configurations of natural materials have inspired authors to mimic the natural structures, giving rise to the concept of bioinspired materials. 1–4 As biological systems have been optimized by nature over millions of years of evolution, they are expected to provide good functional performance. Several works have explored the relationship between structure and properties in biological materials.…”

Section: Introductionmentioning

confidence: 99%

“…Several works have explored the relationship between structure and properties in biological materials. 1–4…”

Section: Introductionmentioning

confidence: 99%

Bioinspired structures for core sandwich composites produced by fused deposition modelling

Bru

Leite

Ribeiro

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part L:

View full text Add to dashboard Cite

Sandwich panels are widely used in many engineering applications where saving weight while maintaining high strength and stiffness is required. The most common core structure in sandwich panels is the two-dimensional regular hexagonal cell shape, denoted as Honeycomb. In recent times, bioinspired materials and structures have become increasingly attractive to researchers, as they provide adequate functional properties. The goal of the present work is to study two new bioinspired structures aimed at improving the performance of sandwich panel cores. Among all the large amount of structures that nature provides, two novel cores inspired in the structures of enamel and of bamboo were chosen. The compressive and flexural properties of these two innovative cellular structures were assessed and compared with the classic honeycomb. All the arrangements were numerically simulated for different relative densities. The fused deposition modelling technique enables to print selected samples in polylactic acid that were experimentally tested in compression and in bending. Results show that the mechanical properties depend strongly on the core geometry, on the relative density and on the cell thickness distribution. A satisfactory agreement was found between finite element results and experimental data. For the same relative density, the bioinspired natural structures proposed in the present study are potential competitors with the traditional core structures in what concerns strength, stiffness and energy absorption.

show abstract

A review of terrestrial, aerial and aquatic keratins: the structure and mechanical properties of pangolin scales, feather shafts and baleen plates

Cited by 28 publications

References 46 publications

Biotransformation of keratin waste to amino acids and active peptides based on cell-free catalysis

Biotransformation of keratin waste to amino acids and active peptides based on cell-free catalysis

Combined proteomics and transcriptomics reveal the genetic basis underlying the differentiation of skin appendages and immunity in pangolin

Bioinspired structures for core sandwich composites produced by fused deposition modelling

Contact Info

Product

Resources

About