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The presence of harmful substances such as dyes in water systems poses a direct threat to the quality of people's lives and other organisms living in the ecosystem. Orange G (OG) is considered a hazardous dye. The existing paper attempts to evaluate a low-cost adsorbent for the effective removal of OG dye. The developed adsorbent Polyaniline@Hydroxyapatite extracted from Cilus Gilberti fish Scale (PANI@FHAP) was elaborated through the application of the in situ chemical polymerization method to incorporate PANI on the surface of naturally extracted hydroxyapatite FHAP. The good synthesis of PANI@FHAP was evaluated through multiple techniques including X-ray diffraction (XRD), Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS), Fourier Transforms Infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) coupled with thermal differential analysis (DTA) analysis. The results reveal a highly ordered disposition of PANI chains on FHAP, resulting in a well-coated FHAP in the PANI matrix. Furthermore, the presence of functional groups on the surface of PANI such as amine (-NH 2 ) and imine (=NH) groups would facilitate the removal of OG dye from contaminated water. The adsorption of OG onto PANI@FHAP was conducted in batch mode and optimized through response surface methodology coupled with box-Behnken design (RSM/BBD) to investigate the effect of time, adsorbent dose, and initial concentration. The outcomes proved that OG adsorption follows a quadratic model (R 2  = 0.989). The kinetic study revealed that the adsorption of OG fits the pseudo-second-order model. On the other hand, the isotherm study declared that the Freundlich model is best suited to the description of OG adsorption. For thermodynamic study, the adsorption of OG is spontaneous in nature and exothermic. Furthermore, the regeneration-reusability study indicates that PANI@FHAP could be regenerated and reused up to five successive cycles. Based on the FTIR spectrum of PANI@FHAP after OG adsorption, the mechanism governing OG adsorption is predominantly driven by π-π interaction, electrostatic interaction, and hydrogen bonding interactions. The obtained results suppose that PANI@FHAP adsorbent can be a competitive material in large-scale applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Commercial mammalian collagen-based membranes used for guided tissue regeneration (GTR) in periodontal defect repair still face significant challenges, including ethical concerns, cost-effectiveness, and limited capacity for periodontal bone regeneration. Herein, an enhanced biomimetic mineralized hydroxyapatite (HAp)-fish-scale collagen (FCOL)/chitosan (CS) nanofibrous membrane was developed. Specifically, eco-friendly and biocompatible collagen extracted from grass carp fish scales was co-electrospun with CS to produce a biomimetic extracellular matrix membrane. An enhanced biomimetic mineralized HAp coating provided abundant active calcium and phosphate sites, which promoted cell osteogenic differentiation, and showed greater in vivo absorption. In vitro experiments demonstrated that the HAp-FCOL/CS membranes exhibited desirable properties with no cytotoxicity, provided a mimetic microenvironment for stem cell recruitment, and induced periodontal ligament cell osteogenic differentiation. In rat periodontal defects, HAp-FCOL/CS membranes significantly promoted new periodontal bone formation and regeneration. The results of this study indicate that low-cost, eco-friendly, and biomimetic HAp-FCOL/CS membranes could be promising alternatives to GTR membranes for periodontal regeneration in the clinic.

Heavy metal pollution, especially in freshwater, is a serious problem for aquatic organisms and human health. In this study, the scales of Capoeta capoeta living in the Karasu River (Turkey), which is estimated to be contaminated with pollutants, especially heavy metals, were examined for structural anomalies. Two stations on the river were selected for this purpose. Fish and surface water samples were taken at the stations. The heavy metal analyses were carried out in the water and the fish tissue. Heavy metal pollution was detected in the surface water. It was also observed that some heavy metals (As, Cu, Cd, Cr, Mn, Pb, Ni, Zn) accumulate in the fish tissue. Significant structural differences were observed on the dorsal surface of the scales, such as interrupted primary radii, damaged circuli, damaged focus, damaged anterior scale margin, broken focus, deformed scale structure, scattered chromatophores, dilatation of primary radii, loss of focus, damaged annuli, symmetry shift in the lateral line canal, eroded circuli, damaged posterior scale margin, double focus, branching in the primary radii, asymmetric circuli, incomplete annuli and interrupted secondary radii in each of the fish collected from the contaminated site. Heavy metals are suspected to be responsible for the structural anomalies in the scales. Based on these observations, it can be said that fish scales can be used as an effective indicator of water quality., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Iron deficiency is widespread throughout the world, supplementing sufficient iron or improving the bioavailability of iron is the fundamental strategy to solve the problem of iron scarcity. Herein, we explored a new form of iron supplement, iron chelates of silver carp scales (SCSCP-Fe) were prepared from collagen peptide of silver carp scales (SCSCP) and FeCl 2 ·4H 2 O, the effects of external environment and simulated gastrointestinal digestive environment on the stability of SCSCP-Fe and the structural changes of peptide iron chelates during digestion were investigated. The results of in vitro iron absorption promotion showed that the iron bioavailability of SCSCP-Fe was higher than that of FeSO 4 . Two potential high iron chelating peptides DTSGGYDEY (DY) and LQGSNEIEIR (LR) were screened and synthesized from the SCSCP sequence by molecular dynamics and LC-MS/MS techniques. The FTIR results displayed that the binding sites of DY and LR for Fe 2+ were the carboxyl group, the amino group, and the nitrogen atom on the amide group on the peptide. ITC results indicated that the chelation reactions of DY and LR with Fe 2+ were mainly dominated by electrostatic interactions, forming chelates in stoichiometric ratios of 1:2 and 1:1, respectively. Both DY and LR had a certain ability to promote iron absorption. The transport of DY-Fe chelate may be a combination of the three pathways: PepT1 vector pathway, cell bypass, and endocytosis, while LR-Fe chelate was dominated by bivalent metal ion transporters. This study is expected to provide theoretical reference and technical support for the high-value utilization of silver carp scales and the development of novel iron supplements., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In the field of bone tissue repair, the treatment of bone defects has always posed a significant challenge. In recent years, the advancement of bone tissue engineering and regenerative medicine has sparked great interest in the development of innovative bone grafting materials. In this study, a novel hydroxyapatite (HA) material was successfully prepared and comprehensively characterized. Antimicrobial experiments and biological evaluations were conducted to determine its efficacy. Based on the aforementioned research findings, 3D printing technology was employed to fabricate HA/chitosan (CS)/ polycaprolactone (PCL) scaffolds. The composition of the scaffold materials was confirmed through X-ray diffractometer (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) tests, while the influence of different HA ratios on the scaffold surface morphology was observed. Additionally, antimicrobial experiments demonstrated the favorable antimicrobial activity of the scaffolds containing 30%HA + 5%CS + PCL. Furthermore, the water contact angle measurements confirmed the superhydrophilicity of the scaffolds. Finally, the excellent bioactivity and ability to promote tissue regeneration of the scaffolds were further confirmed by in vitro and in vivo experiments. This study provides new options for future repair and regeneration of bone tissue and clinical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported herein., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Diabetes mellitus is a chronic metabolic disease with prolonged low-grade inflammation and impaired cellular function, leading to poor wound healing. The treatment of diabetic wounds remains challenging due to the complex wound microenvironment. In view of the prominence of fish scales in traditional Chinese medicine and their wide application in modern medicine, we isolated the intercellular components in the scales of sea bass, obtained a natural composite hydrogel, fish scales gel (FSG), and applied it to diabetic chronic wounds. FSG was rich in collagen-like proteins, and possessed low-temperature gelation properties. In vitro, FSG was biocompatible and promoted fibroblast proliferation by approximately 40 %, endothelial cell migration by approximately 20 % and activated the M1 macrophages. In addition, FSG restored the function of fibroblasts and vascular endothelial cells damaged by high glucose. Importantly, FSG normalized the acute inflammatory response to impaired macrophages in a high-glucose microenvironment. Transcriptome analysis implies that this mechanism may involve enhanced cell signaling and cellular communication, improved sensitivity to cytokines, and activation of the TNF signaling pathway. Animal experiments confirmed that FSG significantly improved wound closure by approximately 15 % in diabetic rats, showing similar effects to acute wounds. In conclusion, the regulation of multiple cellular functions by FSG, especially the counterintuitive ability to induce acute inflammation, promoted diabetic wound healing and provides a novel therapeutic strategy for wound repair in diabetic patients., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Corneal blindness is commonly treated through corneal replacement with allogeneic corneal donors, which may face shortage. Regarding this issue, xenogeneic alternatives are explored. Fish scale-derived scaffolds (FSSs) are among the alternatives due to the lower risk of infection and abundant sources of raw materials. Unfortunately, the information about mechanical, optical, chemical, and biological performances of FSSs for corneal replacements is still scattered, as well as about the fabrication techniques. This study aims to gather scattered pieces of information about the mentioned performances and fabrication techniques of FSSs for corneal replacements. Sorted from four scientific databases and using the PRISMA checklist, eleven relevant articles are collected. FSSs are commonly fabricated using decellularization and decalcification processes, generating FSSs with parallel multilayers or crossed fibers with topographic microchannels. In the collected studies, similar mechanical properties of FSSs to native tissues are discovered, as well as good transparency, light remittance, but poorer refractive indexes than native tissues. Biological evaluations mostly discuss histology, cell proliferations, and immune responses on FSSs, while only a few studies examine the vascularization. No studies completed comprehensive evaluations on the four properties. The current progress of FSS developments demonstrates the potential of FSS use for corneal replacements., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Vertebrate mineralized tissues, present in bones, teeth and scales, have complex 3D hierarchical structures. As more of these tissues are characterized in 3D using mainly FIB SEM at a resolution that reveals the mineralized collagen fibrils and their organization into collagen fibril bundles, highly complex and diverse structures are being revealed. In this perspective we propose an approach to analyzing these tissues based on the presence of modular structures: material textures, pore shapes and sizes, as well as extents of mineralization. This modular approach is complimentary to the widely used hierarchical approach for describing these mineralized tissues. We present a series of case studies that show how some of the same structural modules can be found in different mineralized tissues, including in bone, dentin and scales. The organizations in 3D of the various structural modules in different tissues may differ. This approach facilitates the framing of basic questions such as: are the spatial relations between modular structures the same or similar in different mineralized tissues? Do tissues with similar sets of modules carry out similar functions or can similar functions be carried out using a different set of modular structures? Do mineralized tissues with similar sets of modules have a common developmental or evolutionary pathway? STATEMENT OF SIGNIFICANCE: 3D organization studies of diverse vertebrate mineralized tissues are revealing detailed, but often confusing details about the material textures, the arrangements of pores and differences in the extent of mineralization within a tissue. The widely used hierarchical scheme for describing such organizations does not adequately provide a basis for comparing these tissues, or addressing issues such as structural components thought to be characteristic of bone, being present in dermal tissues and so on. The classification scheme we present is based on identifying structural components within a tissue that can then be systematically compared to other vertebrate mineralized tissues. We anticipate that this classification approach will provide insights into structure-function relations, as well as the evolution of these tissues., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Mosquitoes are a great menace for humankind since they transmit pathogenic organisms causing Malaria, Dengue, Chikungunya, Elephantiasis and Japanese encephalitis. There is an urgent need to discover new and novel biological tools to mitigate mosquito-borne diseases. To develop bioinsecticides through newly developed nanotechnology is another option in the present research scenario. In this study we synthesize and characterize sardine fish scales with silver nitrate by adopting various instrumental techniques such as UV- and FTIR-spectroscopy, energy-dispersive X-ray (EDAX), X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). Toxicity bioassays were conducted with young developmental stages of mosquito vectors. Significant mortality appeared after different life stages of mosquito vectors (young larval and pupal instars were exposed to the nanomaterials). LC 50 values were 13.261 ppm for young first instar larvae and 32.182 ppm for pupae. Feeding and predatory potential of G. affinis, before and after exposure to nanoparticles against mosquito larval (I & II) instars of the mosquitoes showed promising results in laboratory experiments. Feeding potential of mosquito fish without nanoparticle treatment was 79.7% and 70.55% for the first and second instar larval populations respectively. At the nanoparticle-exposed situation the predatory efficiency of mosquitofish was 94.15% and 84.3%, respectively. Antioxidant enzymes like (SOD), (CAT), and (LPO) were estimated in the gill region of sardine fish in control and experimental waters. A significant reduction of egg hatchability was evident after nanoparticle application. It became evident from this study that the nano-fabricated materials provide suitable tools to control the malaria vector Anopheles stephensi in the aquatic phase of its life cycle. This finding suggests an effective novel approach to mosquito control., (© 2021. The Author(s).)

Fish gelatin and its hydrolysates exhibit a variety of biological characteristics, which include antihypertensive and antioxidant properties. In this study, fish gelatins were extracted from extrusion-pretreated tilapia scales, and then subjected to analyses to determine the physicochemical properties and antioxidant activity of the extracted gelatins. Our findings indicate that TSG2 (preconditioned with 1.26% citric acid) possessed the greatest extraction yield, as well as higher antioxidant activities compared with the other extracted gelatins. Hence, TSG2 was subjected to further hydrolyzation using different proteases and ultrafiltration conditions, which yielded four gelatin hydrolysates: TSGH1, TSGH2, TSGH3, and TSGH4. The results showed that TSGH4 (Pepsin + Pancreatin and ultrafiltration < 3000 Da) had a higher yield and greater antioxidant activity in comparison with the other gelatin hydrolysates. As such, TSGH4 was subjected to further fractionation using a Superdex peptide column and two-stage reverse-phase column HPLC chromatography, yielding a subfraction TSGH4-6-2-b, which possessed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity compared with the other fractions. Further LC-ESI/MS/MS analysis of TSGH4-6-2-b suggested two novel peptides (GYDEY and EPGKSGEQGAPGEAGAP), which could have potential as naturally-occurring peptides with antioxidant properties. These promising results suggest that these antioxidant peptides could have applications in food products, nutraceuticals, and cosmetics.

Scales are symbolic characteristic of Lepidoptera; however, nothing is known about the contribution of cuticular proteins (CPs) to the complex patterning of lepidopteran scales. This is because scales are resistant to solubilization, thus hindering molecular studies. Here we succeeded in dissolving developing wing scales from Bombyx mori, allowing analysis of their protein composition. We identified a distinctive class of histidine rich (His-rich) CPs (6%-45%) from developing lepidopteran scales by LC-MS/MS. Functional studies using RNAi revealed CPs with different histidine content play distinct and critical roles in constructing the microstructure of the scale surface. Moreover, we successfully synthesized films in vitro by crosslinking a 45% His-rich CP (BmorCPR152) with laccase2 using N-acetyl- dopamine or N-β-alanyl-dopamine as the substrate. This molecular study of scales provides fundamental information about how such a fine microstructure is constructed and insights into the potential application of CPs as new biomaterials.

Peptides derived from crimson snapper scales (CSSPs) were reported to possess excellent free radical scavenging activities in vitro. In present study, the anti-aging and anti-oxidative stress effects of CSSPs were evaluated in Drosophila melanogaster models. Results showed that the addition of CSSPs in the diets of normal Drosophila could effectively extend their lifespan and improve the motor ability of aged Drosophila. Moreover, CSSPs could protect Drosophila from oxidative damage induced by H 2 O 2 , paraquat and UV irradiation. The extension of lifespan was found to be associated with the effects of CSSPs in improving the antioxidant defense system of Drosophila, manifesting as the reduction of oxidation products MDA and PCO, the elevated activities of T-SOD, CAT and GSH-Px, and the upregulated expression of antioxidant related genes after CSSPs supplemented. Furthermore, CSSPs at 6 mg/mL significantly downregulated mTOR signaling pathway and activated autophagy in aged male Drosophila, and the inhibition on mTOR activation was probably mediated by the antioxidant effects of CSSPs. Our findings suggest that CSSPs have the potential in making dietary supplements against natural aging and oxidative stress in organisms., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Dorsal crest scales and those of the tail spines of the tuatara (Sphenodon punctatus) represent different specializations involved in display and protection. Erection of the dorsal crest occurs in males during combat and courtship, but tail spines are not noticeably involved in these activities. In both scale derivatives corneous beta proteins (CBPs, formerly called beta-keratins) and intermediate filaments keratins (IFKs) were determined by immunolabelling. The dermis is dense with few sparse fibrocytes surrounded by collagen bundles, the latter rather randomly oriented in the crest scales. In the tail ridge scales banded collagen I fibrils form more regular, orthogonally aligned bundles of alternating layers with connections to the basal epidermal membrane. A conglomerate of dermal melanonophores and iridophores is present under the epidermis. The iridophores are the likely origin of the whitish colour of the crest. The epidermis shows a thicker beta-layer with serrated/indented corneocytes in the tail scales while the beta layer is reduced in the crest but contains CBPs. A relatively thick mesos layer is present in both scale derivatives, especially in the crest where its role, aside from limiting transpiration, is not known. The alpha-layer is formed by corneocytes with irregular perimeter and sparse desmosomal remnants. The high labelling intensity for CBPs in the beta-layer disappears in the mesos layer but occurs, albeit strongly reduced, in the alpha-layer as in the other body scales. The take-home message is that the dense dermis and its apical beta-layer strengthen mechanically the ridge spines while the crest is mainly supported by the firm but pliable and less dense or regular dermis., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The extensive discomfort in the expulsion of toxic pollutants even at mild concentrations has demanded the need for prompt methods for the evacuation of dyes and heavy metals. The effective method for depuration of dye from the effluent is by sorption. Chitosan is a bio-polymer which is gaining an increasing interest as one of the sorbents. It was obtained from the crab shells by undergoing several chemical processes and used as an adsorbent for dye, metal removal and also for pharmaceutical purposes. Cross linking it with other co polymers will increase the capacity of adsorption to a maximum level. Fish scales are considered to be a major waste in the food industry and since it takes a long time for decomposing it is considered to be one of the pollutants. Hence it is utilised by converting it into activated carbon by preliminary treatment and into a muffle furnace. The obtained activated carbon is combined with chitosan by using a cross linker and utilised for adsorption mechanism. To analyse the effect of chitosan cross linked with activated carbon obtained from fish scales in adsorption of dye Reactive Blue 9 (RB9) to evaluate the adsorption studies, kinetics, mass transfer studies, thermodynamics of the bio adsorbent.

The ability to distinguish between different migratory behaviours (e.g., anadromy and potamodromy) in fish can provide important insights into the ecology, evolution, and conservation of many aquatic species. We present a simple stable carbon isotope (δ13C) approach for distinguishing between sockeye (anadromous ocean migrants) and kokanee (potamodromous freshwater residents), two migratory ecotypes of Oncorhynchus nerka (Salmonidae) that is applicable throughout most of their range across coastal regions of the North Pacific Ocean. Analyses of kokanee (n = 239) and sockeye (n = 417) from 87 sites spanning the North Pacific (Russia to California) show that anadromous and potamodromous ecotypes are broadly distinguishable on the basis of the δ13C values of their scale and bone collagen. We present three case studies demonstrating how this approach can address questions in archaeology, archival, and conservation research. Relative to conventional methods for determining migratory status, which typically apply chemical analyses to otoliths or involve genetic analyses of tissues, the δ13C approach outlined here has the benefit of being non-lethal (when applied to scales), cost-effective, widely available commercially, and should be much more broadly accessible for addressing archaeological questions since the recovery of otoliths at archaeological sites is rare., Competing Interests: The authors have declared that no competing interests exist.

In diverse organisms, nanostructures that coherently scatter light create structural color, but how such structures are built remains mysterious. We investigate the evolution and genetic regulation of butterfly scale laminae, which are simple photonic nanostructures. In a lineage of buckeye butterflies artificially selected for blue wing color, we found that thickened laminae caused a color shift from brown to blue. Deletion of the optix patterning gene also altered color via lamina thickening, revealing shared regulation of pigments and lamina thickness. Finally, we show how lamina thickness variation contributes to the color diversity that distinguishes sexes and species throughout the genus Junonia . Thus, quantitatively tuning one dimension of scale architecture facilitates both the microevolution and macroevolution of a broad spectrum of hues. Because the lamina is an intrinsic component of typical butterfly scales, our findings suggest that tuning lamina thickness is an available mechanism to create structural color across the Lepidoptera., Competing Interests: RT, FA, NP No competing interests declared, (© 2020, Thayer et al.)

The present study aimed to develop a more biomimetic tissue-engineered oral mucosa equivalent comprising 1% type I tilapia scale collagen scaffold having microstructures mimicking the dermal-epidermal junction of oral mucosa and oral keratinocytes as graft materials for human use. We designed four micropattern prototypes mimicking the dermal-epidermal junction. Using a semiconductor process and soft lithography, negative molds were fabricated to develop microstructures using both polydimethylsiloxane and silicon substrates. Micropattern configurations of dermal-epidermal junctions manufactured from fish collagen consisting of a fibril network using our micropatterning system were well preserved, although the internal fibril network of the pillar pattern was sparse. Mixing 1% chondroitin sulfate with the collagen matrix minimized tissue-engineered oral mucosa equivalent contraction. Histologic examinations showed a flattening of the vertical dimensions of all microstructures and expansion of their pitches, indicating changes in the originally designed configurations. Nonetheless, histologic examinations revealed that a fully differentiated and stratified epithelial layer was developed on all scaffolds, suggesting that the microstructured fish scale collagen scaffolds have potential in the manufacturing of tissue-engineered oral mucosa equivalents for clinical use; however, enhancement of the mechanical properties of micropatterns is required. Our micropatterning technology can also apply to the development of oral mucosa in vitro models.

Among many dermal armors, fish scales have become a source of inspiration in the pursuit of "next-generation" structural materials. Although fish scales function in a hydrated environment, the role of water and intermolecular hydrogen bonding to their unique structural behavior has not been elucidated. Water molecules reside within and adjacent to the interpeptide locations of the collagen fibrils of the elasmodine and provide lubrication to the protein molecules during deformation. We evaluated the contributions of this lubrication and the intermolecular bonding to the mechanical behavior of elasmodine scales from the Black Carp (Mylopharyngodon piceus). Scales were exposed to polar solvents, followed by axial loading to failure and the deformation mechanisms were characterized via optical mechanics. Displacement of intermolecular water molecules by liquid polar solvents caused significant (p ≤ 0.05) increases in stiffness, strength and toughness of the scales. Removal of this lubrication decreased the capacity for non-linear deformation and toughness, which results from the increased resistance to fibril rotations and sliding caused by molecular friction. The intermolecular lubrication is a key component of the "protecto-flexibility" of scales and these natural armors as a system; it can serve as an important component of biomimetic-driven designs for flexible armor systems. STATEMENT OF SIGNIFICANCE: The natural armor of fish has become a topic of substantial scientific interest. Hydration is important to these materials as water molecules reside within the interpeptide locations of the collagen fibrils of the elasmodine and provide lubrication to the protein molecules during deformation. We explored the opportunity for tuning the mechanical behavior of scales as a model for next-generation engineering materials by adjusting the extent of hydrogen bonding with polar solvents and the corresponding interpeptide molecular lubrication. Removal of this lubrication decreased the capacity for non-linear deformation and toughness due to an increase in resistance to fibril rotations and sliding as imparted by molecular friction. We show that intermolecular lubrication is a key component of the "protecto-flexibility" of natural armors and it is an essential element of biomimetic approaches to develop flexible armor systems., Competing Interests: Declaration of Competing Interest The authors have no conflicts to declare., (Copyright © 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

New peptide based hybrid scaffolds were prepared by blending two different fish scale derived hydroxyapatite with functionalized peptide nanofibers for potential applications in periodontal tissue regeneration. The nanofibers were prepared by self-assembly of the newly designed peptide bolaamphiphile Bis (N-α-amido-glutamic acid) 1,7 heptane tetracarboxylate and functionalized with a segment of the tyrosine rich amylogenin peptide sequence MPLPPHPGHPGYINF followed by polygalacturnonic acid and hydroxyapatite derived from salmon or red-snapper fish scales. The binding interactions of the components of the scaffold was confirmed by FTIR spectroscopy as well as SEM imaging. Hybrids scaffolds with salmon scale derived HaP showed higher mechanical strength and Young's Modulus compared to snapper scale derived scaffolds. Our results indicated that while both the scaffolds supported cell proliferation and efficiently formed cell-scaffold matrices with gingival fibroblasts, we observed greater alignment of the cells in the case of scaffolds that contained snapper scale derived hydroxyapatite. Furthermore, higher differentiation ability into osteoblast like cells was seen in the case of the snapper scale derived HaP based scaffolds. Our studies indicate that the hybrid peptide nanofiber scaffold matrices, particularly those prepared using snapper scales may have significant utility in the development of biomaterials for periodontal tissue regeneration., Competing Interests: Declaration of competing interest All authors declare no conflict of interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Collembola are ancient arthropods living in soil with extensive exposure to dirt, bacteria, and fungi. To protect from the harsh environmental conditions and to retain a layer of air for breathing when submerged in water, they have evolved a superhydrophobic, liquid-repelling cuticle surface. The nonfouling and self-cleaning properties of springtail cuticle make it an interesting target of biomimetic materials design. Recent research has mainly focused on the intricate microstructures at the cuticle surface. Here we study the role of the cuticle chemistry for the Collembola species Orchesella cincta (Collembola, Entomobryidae). O. cincta uses a relatively simple cuticle structure with primary granules arranged to function as plastrons. In contrast to the Collembolan cuticle featuring structures on multiple length scales that is functional irrespective of surface chemistry, we found that the O. cincta cuticle loses its hydrophobic properties after being rinsed with dichloromethane. Sum frequency generation spectroscopy and time-of-flight secondary ion mass spectrometry in combination with high-resolution mass spectrometry show that a nanometer thin triacylglycerol-containing wax layer at the cuticle surface is essential for maintaining the antiwetting properties. Removal of the wax layer exposes chitin, terpenes, and lipid layers in the cuticle. With respect to biomimetic applications, the results show that, combined with a carefully chosen surface chemistry, superhydrophobicity may be achieved using a relatively unsophisticated surface structure rather than a complex, re-entrant surface structure alone.

The physicochemical properties and hepatoprotective effects of fish scales peptides (FSP) and the glycated peptides conjugated with xylose via Maillard reaction (FSP-MRPs) were investigated. Results showed that the FSP was rich in oligopeptides within 2-10 amino acids, the degree of grafting of FSP-MRPs was 52.97 ± 1.58% and the antioxidant activities in vitro of FSP were improved through Maillard reaction. In order to investigate the antioxidant activities of FSP-MRPs after digestion, the simulated gastrointestinal digestion experiments of FSP and FSP-MRPs in vitro were conducted. Results indicated that the antioxidant activities of FSP and FSP-MRPs remained as stronger as before even under the digestive conditions. Furthermore, FSP-MRPs could significantly reduce the elevated activities of serum aspartate aminotransferase and alanine aminotransferase, decrease the elevated the levels of hepatic malondialdehyde and triglyceride, and inhibit the decrease of hepatic superoxide dismutase, catalase and glutathione peroxidase caused by alcohol-induced liver damage. These findings suggest that the glycated peptides formed by FSP and xylose via Maillard reaction may be potential to be exploited as a potential functional ingredient in food industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Presence of heavy metal in industrial wastewater is hazardous to the surrounding environment. Biosorption of heavy metal is an effective technology for the treatment of industrial wastewater. This research work has been carried out on removal of chromium (III) metal ions by employing waste fish scales as bioadsorbent. A batch adsorption process was carried out with different adsorbent dosage, solution pH and contact time. The results show the highest 99.7518 % chromium (III) metal ions at bioadsorbent dosage 0.8 g, pH of the solution 5 and contact time 90 min, initial concentration 150 mg/l chromium ion. The adsorption isotherms data fitted well with the Langmuir isotherm model with R 2 = 0.9998, q max = 18.3486 mg/g, and R L = 0.00007325. As well as pseudo-first and second kinetics model was also analyzed for the description of adsorption and found to be well fitted (R 2 = 1) for adsorption kinetics. The surface properties activated fish scales and chromium loaded fish scale were investigated by scanning electron microscopy, X-ray spectroscopy, Fourier-transform infrared spectroscopy, and thermal analysis and agree with outcomes., (Copyright © 2019. Published by Elsevier Ltd.)

Background: The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely than heterospecifics, is important because by acting earlier in the life cycle it has the potential to prevent a larger fraction of hybridization. The mechanism behind such male mate preference is unknown. Here we investigate if the female cuticular hydrocarbon (CHC) profile could be the signal behind male courtship., Results: While males of the two species display nearly identical CHC profiles, females have different, albeit overlapping profiles and some females (between 15 and 45%) of both species display a male-like profile distinct from profiles of typical females. We classified CHC females profile into three categories: G. firmus-like (F; including mainly G. firmus females), G. pennsylvanicus-like (P; including mainly G. pennsylvanicus females), and male-like (ML; including females of both species). Gryllus firmus males courted ML and F females more often and faster than they courted P females (p < 0.05). Gryllus pennsylvanicus males were slower to court than G. firmus males, but courted ML females more often (p < 0.05) than their own conspecific P females (no difference between P and F). Both males courted heterospecific ML females more often than other heterospecific females (p < 0.05, significant only for G. firmus males)., Conclusions: Our results suggest that male mate preference is at least partially informed by female CHC profile and that ML females elicit high courtship behavior in both species. Since ML females exist in both species and are preferred over other heterospecific females, it is likely that this female type is responsible for most hybrid offspring production.

Cold stage adversely affects cell proliferation and cell viability of probiotics such as Streptococcus thermophilus in food industry, new type of cryoprotectants continues to be needed. Gelatin-based antifreeze peptide becomes a popular topic because of its cryoprotective effects on cold-stressed probiotics. In this study the effects of tilapia scales antifreeze peptides (TSAPP) on cell viability and oxidant stress of S. thermophilus during cold stage were investigated. The results showed that the percentage of viable cells was increased 10.85 folds compared with control groups. Addition of TSAPP activated the activities of ATPases, relieved the hyperpolarization of cell membrane potential and regulated the intracellular Ca 2+ concentration. Furthermore, TSAPP significantly inhibited reactive oxygen species level and malonaldehyde content in cells. Under cryopreservation with TSAPP, cells of S. thermophilus maintained higher activities of antioxidant enzymes including catalase, peroxidase and total antioxidant capacity. These findings indicate that TSAPP likely offered its cellular protection by maintaining membrane integrity and alleviation of oxidative stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Crimson snapper is an important marine economy fish, and its scales are rich in collagen. Crimson snapper scale peptides (CSSPs) obtained from crimson snapper scales by enzymatic hydrolysis exhibited significantly antioxidant activities to DPPH, ABTS and hydroxyl radicals in vitro. In vivo antioxidant and anti-aging effects of CSSPs on the Drosophila melanogaster aging model constructed by lard were investigated in this study. The results showed that CSSPs could prolong the mean lifespan, 50% survival days and the maximum lifespan of Drosophila, and especially when the concentration of CSSPs was increased to 6 mg mL-1, the mean lifespan of male and female Drosophila increased by 21.2% and 26.2%, respectively, indicating the effective life extension effect of CSSPs. Meanwhile, the addition of CSSPs effectively reduced the contents of malondialdehyde (MDA) and protein carbonylation (PCO) and increased the levels of total superoxide dismutase (T-SOD) and catalase (CAT) in Drosophila, which showed a significant dose dependence. Besides, the antioxidant-related genes SOD1, SOD2 and CAT were up-regulated in Drosophila when fed with diets containing CSSPs. In conclusion, CSSPs played an antioxidant and anti-aging role by reducing the accumulation of peroxide products and improving the activity of antioxidant enzymes, as well as by up-regulating the expression of antioxidant-related genes. The results suggest that CSSPs have potential to be used in the food and healthcare industries as potential food-borne antioxidant and anti-aging agents.

The utilization of fish scale-derived biosorbent for immobilization of cadmium and lead in polluted sediment was thoroughly investigated in this study. Fish scale (FS) biomass was chemically and physically treated. The FS biomass treated with acid (0.1 M HCl), alkali (0.1 M NaOH) and hydrothermally, showed minimum removal capacity. While, FS treated hydrothermally along with acid showed the maximum removal efficiency of metal ions. We used different dosages (0%, 2.5%, 5%, 10%, 15%, and 20%) of FS biosorbent in the sediment. Isotherm modelling showed that this biosorbent can hold 89.30 and 92.65 mg/g of Cd and Pb on its surface. This indicated that prepared FS biosorbent has enough potential to adsorb Cd and Pb ions on its surface from the sediment. Compared to the control, sediment treated with 20% FS showed the highest immobilization capacities for Pb (92.9%), and Cd (87.9%). The values of partition coefficient (K d ) increased by 83% for Pb and 78% for Cd, which specified that availability of free ions of Pb and Cd in the aquatic system was successfully decreased. The sediment treated with 20% FS biosorbent showed 70-80% immobilization of Cd and Pb from mobile and exchangeable fractions that ultimately decreased the bioavailability of metal ions to the biota. Inclusively, compared to control, sediment served with 20% FS biosorbent showed higher level of Pb and Cd ions in residual fraction near by 80%. The prepared FS biosorbent had shown its potential in immobilizing the Cd and Pb ions from sediment as a cheap and ecologically feasible method for amendment., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Fish-scale waste is rich in biocompatible hydroxyapatite (HAp). In the present study, an environmentally friendly method of extracting HAp from fish-scale waste was developed in an effort to promote environmental sustainability. Deep eutectic solvents (choline chloride/glycerol, 1/2) were used to extract HAp from bighead carp (Aristichthys nobilis) scales. A relatively high extraction rate of 47.67% ± 1.81% was obtained under optimum conditions (70 °C, a solid/liquid ratio of 1/15 g/g and a 2.5 hr extraction time). The obtained HAp was characterized and its purity was determined using Fourier transform infrared spectroscopy and X-ray diffraction, respectively. The chemical composition was performed by energy-dispersive X-ray spectrometry and inductively coupled plasma-optical emission spectroscopy. Its morphology and particle size were observed using scanning electron microscopy and particle size distribution analysis. Thermogravimetric analysis was used to determine its thermal stability. Blood compatibility was determined using a hemolytic test. The results showed that this extraction yielded HAp with the irregular morphology, the higher Ca/P ratio, good thermal stability, and blood compatibility, indicating that the proposed method is an excellent alternative for the improved utilization of fish scale waste. PRACTICAL APPLICATION: Biocompatible hydroxyapatite (HAp) was extracted from fish scale (FS) waste by using an environmentally friendly deep eutectic solvent. The optimized extraction and structure characterization of extracted HAp were investigated in this study. The results showed that the extracted HAp had the irregular morphology, the higher Ca/P ratio, good thermal stability, and blood compatibility, which indicated that the proposed method was an excellent alternative to improving the utilization of FS waste., (© 2019 Institute of Food Technologists®.)

We extracted collagen (CL) from the scales of Ctenopharyngodon idella and fabricated a CL self-assembly film. Catalase (CAT) was immobilized on the films using cross-linking, adsorption, and embedding methods. The activity and operational stability of immobilized CAT were investigated, along with the influence of the concentration of glutaraldehyde (GTA) and of the initial concentration of embedded CAT. The results showed that the CL triple helix remained intact. Differential scanning calorimetry data showed that the thermal stability of CL was significantly improved by neutral salt-induced self-aggregation and GTA cross-linking. The immobilized enzyme had high activity and good operational stability. When the enzyme concentration reached 0.5 mg/mL, immobilized enzyme activity of grass carp scales reached a maximum of 2596 U/g, and after twenty-two uses, enzyme activity remained above 50%, and it could be reused >45 times (CAT = 0.5 mg/mL, GTA = 5%, Temperature = 30 °C, pH = 7). Moreover, the optimum temperature and pH of immobilized CAT were 35 °C and 7, respectively, while the same for free CAT was 30 °C and 7, respectively. This indicated that immobilization of CAT has a protective effect., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The outermost surface of insect cuticle is a high-performance interface that provides wear protection, hydration, camouflage and sensing. The complex and inhomogeneous structure of insect cuticle imposes stringent requirements on approaches to elucidate its molecular structure and surface chemistry. Therefore, a molecular understanding and possible mimicry of the surface of insect cuticle has been a challenge. Conventional optical and electron microscopies as well as biochemical techniques provide information about morphology and chemistry but lack surface specificity. We here show that a near edge X-ray absorption fine structure microscope at the National Synchrotron Light Source can probe the surface chemistry of the curved and inhomogeneous cuticle of the African flower scarab. The analysis shows the distribution of organic and inorganic surface species while also hinting at the presence of aragonite at the dorsal protrusion region of the Eudicella gralli head, in line with its biological function.

Stable isotope analysis (SIA) was used to examine the isotopic relationships between dorsal muscle and fin, scale and epidermal mucus in pike Esox lucius. δ 13 C and δ 15 N varied predictably within each tissue pairing, with conversion factors calculated for the surrogate tissues, enabling their application to the non-lethal sampling of E. lucius for SIA., (© 2019 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.)

A vital trait in insects is their cuticular hydrocarbon (CHC) profile, which protects the insect against desiccation and serves in chemical communication. Due to these functions, CHC profiles are shaped by both climatic conditions and biotic interactions. Here, we investigated CHC differentiation in the neotropical parabiotic ant species Crematogaster levior and Camponotus femoratus, which mutualistically share a nest. Both consist of two cryptic species each (Cr. levior A and B and Ca. femoratus PAT and PS) that differ genetically and possess strongly different CHC profiles. We characterized and compared CHC profiles of the four cryptic species in detail. Our results suggest that Cr. levior A, Ca. femoratus PAT and Ca. femoratus PS adapted their CHC profiles to the parabiotic lifestyle by producing longer-chain CHCs. At the same time, they changed their major CHC classes, and produce more alkadienes and methyl-branched alkenes compared to Cr. levior B or non-parabiotic species. The CHC profiles of Cr. levior B were more similar to related, non-parabiotic species of the Orthocrema clade than Cr. levior A, and the chain lengths of B were similar to the reconstructed ancestral state. Signals of both the parabiotic partner (biotic conditions) and climate (abiotic conditions) were found in the CHC profiles of all four cryptic species. Our data suggest that mutualisms shaped the CHC profiles of the studied species, in particular chain length and CHC class composition. Beside this, signals of the parabiotic partners indicate potential impacts of biotic interactions, via chemical mimicry or chemical camouflage.

Composite films containing different amounts of potassium sorbate (KS) were prepared by using fish scale collagen (Col) and polyvinyl alcohol (PVA). Fourier transform infrared spectroscopy (FTIR), light transmittance, mechanical, water vapor transmission rate (WVTR), and the antibacterial properties of the composite films were analyzed. The results showed that the addition of Col significantly reduced the light transmittance of the composite film, but KS had no significant effect on the light transmission. The tensile strength decreased first and then increased with the addition of KS, while the WVTR increased first and then decreased. The composite film exhibited a certain degree of antibacterial properties against E. coli and S. aureus . In addition, we found that ultrasonic treatment reduced the WVTR, and also improved tensile strength and elongation at break of the composite films, but had no significant effect on other properties. The KS/Col/PVA films have the potential to be used as antimicrobial food packaging.

Recently, biologically active natural macromolecules have come into prominence to be used as potential materials in scaffold design due to their unique characteristics which can mimic the human tissue structure with their physical and chemical similarity. Among them, fish scale (FS) is a biologically active material with its structural similarity to bone tissue due to including type I collagen and hydroxyapatite and also have distinctive collagen arrangement. In the present study, it is aimed to design a novel composite scaffold with FS incorporation into chitosan (CH) matrix for bone tissue regeneration. Therefore, two biological macromolecules, fish scale and chitosan, were combined to produce bio-composite scaffold. First, FS were decellularized with the chemical method and disrupted physically as microparticles (100 μm), followed by dispersal in CH with ultrasonic homogenisation, CH/FS scaffolds were fabricated by lyophilization technique. Scaffolds were characterized physically, chemically, mechanically, and morphologically. SEM and porosity results showed that CH/FS scaffolds have uniform pore structure showing high porosity. Mechanical properties and degradation rate are enhanced with increasing FS content. In vitro cytotoxicity, proliferation and osteogenic activity of the scaffolds were evaluated with SaOS-2 cell line. CH/FS scaffolds did not show any cytotoxicity effect and the cells were gradually proliferated during culture period. Cell viability results showed that, FS microparticles had a proliferative effect on SaOS-2 cells when compared to control group. ALP activity and biomineralization studies indicated that FS microparticle reinforcement increased osteogenic activity during culture period. As a biological macromolecule with unique characteristics, FS was found as cytocompatible and provided promising effects as reinforcement agents for polymeric scaffolds. In conclusion, fabricated CH/FS bio-composites showed potential for bone tissue engineering applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This study aimed to explore a potential use of fish scale-derived gelatin nanofibrous scaffolds (GNS) in tissue engineering due to their biological and economical merits. Extraction of gelatin was achieved via decalcification, sonication and lyophilization of mixed fish scales. To fabricate nano-scale architecture of scaffolds analogous to natural extracellular matrix, gelatin was rendered into nanofibrous matrices through 6-h electrospinning, resulting in the average diameter of 48 ± 12 nm. In order to improve the water-resistant ability while retaining their biocompatibility, GNS were physically crosslinked with ultraviolet (UV) irradiation for 5 min (UGN5), 10 min (UGN10) and 20 min (UGN20). On average, the diameter of nanofibers increased by 3 folds after crosslinking, however, Fourier transform infrared spectroscopy analysis confirmed that no major alterations occurred in the functional groups of gelatin. A degradation assay showed that UGN5 and UGN10 scaffolds remained in minimum essential medium for 14 days, while UGN20 scaffolds degraded completely after 10 days. All UGN scaffolds promoted adhesion and proliferation of human keratinocytes, HaCaT, without causing an apparent cytotoxicity. UGN5 scaffolds were shown to stimulate a better growth of HaCaT cells compared to other scaffolds upon 1 day of incubation, whereas UGN20 had a long-term effect on cells exhibiting 25% higher cell proliferation than positive control after 7 days. In the wound scratch assay, UGN5 scaffolds induced a rapid cell migration closing up to 79% of an artificial wound within 24 h. The current findings provide a new insight of UGN scaffolds to serve as wound dressings in the future. In the wound scratch assay, UGN5 induced a rapid cell migration closing up to 79% of an artificial wound within 24 h.

Long-chain cuticular hydrocarbons (CHC) are key components of chemical communication in many insects. The parasitoid jewel wasps from the genus Nasonia use their CHC profile as sex pheromone and for species recognition. The standard analytical tool to analyze CHC is gas chromatography coupled with mass spectrometric detection (GC/MS). This method reliably identifies short- to long-chain alkanes and alkenes, but CHC with more than 40 carbon atoms are usually not detected. Here, we applied two laser mass spectrometry (MS) techniques, namely direct laser desorption/ionization (d)LDI and silver-assisted (Ag-)LDI MS, respectively, to analyze CHC profiles of N. vitripennis, N. giraulti, and N. longicornis directly from the cuticle or extracts. Furthermore, we applied direct analysis in real-time (DART) MS as another orthogonal technique for extracts. The three methods corroborated previous results based on GC/MS, i.e., the production of CHC with carbon numbers between C25 and C40. However, we discovered a novel series of long-chain CHC ranging from C41 to C51/C52. Additionally, several previously unreported singly and doubly unsaturated alkenes in the C31-C39 range were found. Use of principal component analysis (PCA) revealed that the composition of the newly discovered CHC varies significantly between species, sex, and age of the animals. Our study adds to the growing literature on the presence of very long-chain CHC in insects and hints at putative roles in insect communication. Graphical abstract.

A significant body of literature suggests that aquatic pollutants can interfere with the physiological function of the fish hypothalamic-pituitary-interrenal (HPI) axis, and eventually impair the ability to cope with subsequent stressors. For this reason, development of accurate techniques to assess fish stress responses have become of growing interest. Fish scales have been recently recognized as a biomaterial that accumulates cortisol, hence it can be potentially used to assess chronic stress in laboratory conditions. We, therefore, aimed to evaluate the applicability of this novel method for cortisol assessment in fish within their natural environment. Catalan chub (Squalius laietanus) were sampled from two sites; a highly polluted and a less polluted (reference) site, in order to examine if habitat quality could potentially influence the cortisol deposition in scales. We also evaluated the seasonal variation in scale cortisol levels by sampling fish at three different time points during spring-summer 2014. In each sampling, blood was collected to complement the information provided by the scales. Our results demonstrated that blood and scale cortisol levels from individuals inhabiting the reference site were significantly correlated, therefore increasing the applicability of the method as a sensitive-individual measure of fish HPI axis activity, at least in non-polluted habitats. Since different environmental conditions could potentially alter the usefulness of the technique, results highlight that further validation is required to better interpret hormone fluctuations in fish scales. Scale cortisol concentrations were unaffected by habitat quality although fish from the polluted environment presented lower circulating cortisol levels. We detected a seasonal increase in scale cortisol values concurring with an energetically costly period for the species, supporting the idea that the analysis of cortisol in scales reveals changes in the HPI axis activity. Taken together, the present study suggests that cortisol levels in scales are more likely to be influenced by mid-term, intense energetically demanding periods rather than by long-term stressors. Measurement of cortisol in fish scales can open the possibility to study novel spatio-temporal contexts of interest, yet further research is required to better understand its biological relevance., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Cold stress adversely affects cell viability and acidification, and new cryoprotective methods continue to be needed in cold-chain food industry. Given this, we investigated the cryoprotective effects and action mechanism of antifreeze peptides obtained from tilapia scales (TSAPP) on Streptococcus thermophilus during cold stress. Our results showed that the molecular weight of TSAPP ranged from 180 to 2000 Da and its thermal hysteresis activity was 0.29 °C. Growth of S. thermophilus was improved after treatment with TSAPP (1 mg/mL) under cold stress. This growth was notable when compared with the effects of other cryoprotectants. Furthermore, TSAPP improved the metabolic activity of S. thermophilus during cold stress. TSAPP likely offered its cellular protection by maintaining cell membrane fluidity through hydrogen bonding of the phospholipid bilayer. These results indicate that TSAPP has potential as a novel biological peptide material with cryoprotective activity for future use in probiotic or other processed food applications.

Blood is considered a suitable biomonitoring matrix for evaluating relatively recent exposure to environmental contaminants since abrupt changes in exposure regimes are rapidly reflected in blood. On the other hand, keratinized tissues, such as turtle scutes, are known to integrate trace element exposure over relatively long time periods. This study aimed to test the use of the differences in blood and scute to inform on the historical trace element exposure of green turtles. We propose a blood-scute kinetic model to predict how an increase in exposure would affect the concentrations in these two matrices over time. We then tested the relationship between blood and scute concentrations for 19 trace elements in two green turtle populations presumed to experience relatively constant exposure conditions. Significant log-log and linear correlations were observed between blood and scute concentrations for Co, As, Mo, Sb, and Cd. We then analysed blood-scute ratios in turtles from two coastal sites with known elevated exposure to various trace elements from previous studies. Deviations from the steady-state were clearly evident in these coastal turtles (for Co and Cd) and were consistent with the model prediction of changes in exposure. These field data provide evidence that blood-scute ratios can provide a valuable tool for examining the historical trace element exposure of turtles. We further present a method by which the general model may be refined and validated, by using data from individual turtles that had been recaptured across multiple years. Although the timeframe and number of recaptured samples available for this study were limited, the temporal changes in blood-scute ratios in these animals were generally consistent with those suggested by the model. Thus, the ratio between paired blood and scute trace element concentrations could be used to establish a temporal exposure index in turtles., (Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.)

A novel material for making capsules was prepared with tilapia scale gelatin and konjac glucomannan (KGM). Rheological behaviors of gelatin with KGM at different levels (0.1%, 0.15%, and 0.2%, w/w) were investigated. The highest values (P < 0.05) of gel strength (518.33 ± 6.17 g) and melting temperature (39.7 ± 0.11 °C) could be observed at the gelatin solution with 0.15% (w/w) KGM. The tensile strength (TS) and elongation at break (EAB) of the films increased with the increasing of KGM. The water contact angle was enhanced with the increasing of KGM, indicating the decrease of the film hydrophilicity. XRD and FTIR showed the interactions between gelatin and KGM. Gelatin solution with 0.15% KGM is suitable for preparing capsules. Drug dissolution test in vitro showed the shell rupture time is in range of 3-5 min, and 80% of the drugs were released within 10 min. Therefore, the composite materials made of tilapia scale gelatin and KGM can be utilized for hard capsules., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Oxidative stress is regarded as one of the most important factors associated with many diseases, such as atherosclerosis, cancer, and diabetes. Various chemicals are released into the environment, causing environmental pollution. Importantly, many of them may cause damage to organisms through oxidative stress. In this work, we investigated the possible protective effects of Nile tilapia (Oreochromis niloticus) scale collagen hydrolysate (TSCH) (molecular weight approximately 4 kDa) against tributyltin (TBT)-induced oxidative stress in vitro. The results showed that pretreatment with TSCH protected against decreases in cell viability and changes in cell morphology in HepG2 cells exposed to TBT. Treatment with TSCH reduced the TBT-induced elevation in malondialdehyde (MDA) levels in HepG2 cells in a dose-dependent manner. Pretreatment with TSCH increased glutathione reductase (GR) and superoxide dismutase (SOD) activity. Moreover, TSCH decreased the expression of the proapoptotic protein Bax, reducing apoptosis. These results suggest that the protective mechanism of TSCH may be associated with its ability to scavenge MDA, increase antioxidant enzyme activity and downregulate the expression of Bax.

Fish scales are laminated composites that consist of plies of unidirectional collagen fibrils with twisted-plywood stacking arrangement. Owing to their composition, the toughness of scales is dependent on the intermolecular bonding within and between the collagen fibrils. Adjusting the extent of this bonding with an appropriate stimulus has implications for the design of next-generation bioinspired flexible armours. In this investigation, scales were exposed to environments of water or a polar solvent (i.e. ethanol) to influence the extent of intermolecular bonding, and their mechanical behaviour was evaluated in uniaxial tension and transverse puncture. Results showed that the resistance to failure of the scales increased with loading rate in both tension and puncture and that the polar solvent treatment increased both the strength and toughness through interpeptide bonding; the largest increase occurred in the puncture resistance of scales from the tail region (a factor of nearly 7×). The increase in strength and damage tolerance with stronger intermolecular bonding is uncommon for structural materials and is a unique characteristic of the low mineral content. Scales from regions of the body with higher mineral content underwent less strengthening, which is most likely the result of interference posed by the mineral crystals to intermolecular bonding. Overall, the results showed that flexible bioinspired composite materials for puncture resistance should enrol constituents and complementary processing that capitalize on interfibril bonds.

The Australian lungfish has been studied for more than a century without any knowledge of the longevity of the species. Traditional methods for ageing fish, such as analysis of otolith (ear stone) rings is complicated in that lungfish otoliths differ from teleost fish in composition. As otolith sampling is also lethal, this is not appropriate for a protected species listed under Australian legislation. Lungfish scales were removed from 500 fish from the Brisbane, Burnett and Mary rivers. A sub-sample of scales (85) were aged using bomb radiocarbon techniques and validated using scales marked previously with oxytetracycline. Lungfish ages ranged from 2.5-77 years of age. Estimated population age structures derived using an Age Length Key revealed different recruitment patterns between river systems. There were statistically significant von Bertalanffy growth model parameters estimated for each of the three rivers based on limited sample sizes. In addition, length frequency distributions between river systems were also significantly different. Further studies will be conducted to review drivers that may explain these inter-river differences., Competing Interests: The authors have declared that no competing interests exist in considering their commercial partner. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

Textile industry wastewater has become a cause of concern to environmentalists due to its toxic composition and the difficulty of breaking down certain dyes. In this study, modified fish scales of Sardinella brasiliensis (SSb) were used as an alternative for a low-cost adsorbent to remove dyes from textile wastewaters. Adsorption efficiency was assessed by measuring the general, kinetic, and thermodynamic physico-chemical parameters of adsorption isotherms, using Reactive Turquoise Blue 15 (RTB15) and Reactive Red 120 (RR120) dyes as adsorbate models, as local textile industries commonly use these dyes. The isothermal data from the batch experiments were inserted in the Langmuir, Freundlich, and Langmuir-Freundlich (SIPS) equations; the Langmuir isotherm equation showed the most appropriate. The thermodynamic parameters showed that adsorption of dyes by the modified SSb adsorbent was an endothermic yet spontaneous process in the case of RR120. Sorbent-based on SSb material was concluded as adsorbing both of the tested dyes. Because of its abundant availability, and the small amount of activation needed to turn it into an adsorbent, this biowaste can be employed as a low-cost alternative for removal of dyes in the treatment of textile wastewater.

It is urgent to develop a rapid, reliable, and in-site determination method to detect or monitor trace amounts of toxic substances in the field. Here, we report an alternative surface-enhanced Raman scattering (SERS) method coupled with a portable Raman device on a plasmonic three-dimension (3D) hot spot sensing surface. Plasmonic Ag nanoparticles (AgNPs) were uniformly deposited on 3D TiO 2 nanopore arrays as a sensitive SERS substrate, and further coated with graphene oxide (GO). We demonstrate the plasmon-induced SERS enhancement (5.8-fold) and the improvement of catalytic activity by incorporation of plasmonic AgNPs into the 3D TiO 2 nanopore arrays. The modification of GO on the TiO 2 -Ag nanopore array further increases by a 6.2-fold Raman enhancement compared to TiO 2 -Ag while maintaining good uniformity (RSD < 10%). The optimized TiO 2 -Ag-GO substrate shows powerful quantitative detection potential for drug residues in fish scales via a simple scrubbing method, and the limit of detection (LOD) for crystal violet (CV) was 10 -8 M. The SERS substrate also showed detection practicability of pesticide residues in banana peel with an LOD of 10 -7 M. In addition, our TiO 2 -Ag-GO substrate exhibits excellent SERS self-monitoring performance for catalytic reduction of multiple organics in NaBH 4 solution, and the substrate shows good recyclability of 6 cycles. Such a 3D TiO 2 -Ag-GO substrate is a promising SERS substrate with good sensitivity, uniformity, and reusability, and may be utilized for further miniaturization for point of analytical applications.

The ability of the DGT technique to predict Hg 2+ bioavailability for input tissues (skin, gills, and scales) of common carp in the presence of chloride ions and humic acid (HA) was evaluated. The mercury accumulation by the DGT units and input tissues of carp decreased with an increasing concentration of chloride ions (29-180 mg L -1 ) and HA (0-5 mg L -1 ). In the presence of chloride ions and HA, statistically significant correlations (Pearson's correlation coefficients 0.731-0.954) were determined between the rate of mercury accumulation by input tissues of carp and the rate of mercury accumulation by the DGT units. The laboratory experiments suggest the possibility of using the DGT technique for predicting the mercury bioaccumulation in natural aquatic ecosystems instead of commonly used input tissues of fish., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In this report, acid-soluble collagen (ASC-MC) and pepsin-soluble collagen (PSC-MC) were extracted from the scales of miiuy croaker ( Miichthys miiuy ) with yields of 0.64 ± 0.07% and 3.87 ± 0.15% of dry weight basis, respectively. ASC-MC and PSC-MC had glycine as the major amino acid with the contents of 341.8 ± 4.2 and 344.5 ± 3.2 residues/1000 residues, respectively. ASC-MC and PSC-MC had lower denaturation temperatures (32.2 °C and 29.0 °C for ASC-MC and PSC-MC, respectively) compared to mammalian collagen due to their low imino acid content (197.6 and 195.2 residues/1000 residues for ASC-MC and PSC-MC, respectively). ASC-MC and PSC-MC were mainly composed of type I collagen on the literatures and results of amino acid composition, SDS-PAGE pattern, ultraviolet (UV) and Fourier-transform infrared spectroscopy (FTIR) spectra. The maximum solubility of ASC-MC and PSC-MC was appeared at pH 1⁻3 and a sharp decrease in solubility was observed when the NaCl concentration was above 2%. Zeta potential studies indicated that ASC-MC and PSC-MC exhibited a net zero charge at pH 6.66 and 6.81, respectively. Furthermore, the scavenging capabilities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, superoxide anion radical and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical of ASC-MC and PSC-MC were positively correlated with their tested concentration ranged from 0 to 5 mg/mL and PSC-MC showed significantly higher activity than that of ASC-MC at most tested concentrations ( p < 0.05). In addition, the scavenging capability of PSC-MC on hydroxyl radical and superoxide anion radical was higher than those of DPPH radical and ABTS radical, which suggested that ASC-SC and PSC-SC might be served as hydroxyl radical and superoxide anion radical scavenger in cosmeceutical products for protecting skins from photoaging and ultraviolet damage.

Fish gelatin hydrolysates have been shown to possess various biological activities due to their unique Gly-Pro-Y and Gly-X-Hyp sequences. In the current study, fish gelatin was extracted from non-extruded milkfish scale (FSG1) or extrusion-pretreated milkfish scale (FSG2); extracted gelatins were hydrolyzed with different combinations of Flavourzyme and Alcalase to give four different hydrolysates, namely: FSGH1 (FSG1 hydrolyzed with Flavourzyme), FSGH2 (FSG1 hydrolyzed with Alcalase + Flavourzyme), FSGH3 (FSG2 hydrolyzed with Flavourzyme), and FSGH4 (FSG2 hydrolyzed with Alcalase + Flavourzyme). The extrusion-pretreatment process enhanced the extraction yield of gelatin from fish scale. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) analyses showed the extracts FSG1 and FSG2 possessed characteristics of gelatin. Moreover, the physicochemical characteristics of FSGH1⁻FSGH4 were examined by analyses of their degree of hydrolysis, amino acid composition, UV spectrum, FTIR spectrum, molecular weight, and RP-HPLC profile. Additional biological functional analyses showed that all of the studied gelatin hydrolysates FSGH1⁻FSGH4 possessed antioxidant activity dose-dependently as revealed by DPPH scavenging, ABTS scavenging, and reducing power analyses. In addition, FSGH2 and FSGH4 showed higher angiotensin-I-converting enzyme (ACE)-inhibitory activity as compared to FSGH1 and FSGH3. Taken together, FSGH2 and FSGH4 showed high antioxidant activity and potent anti-ACE activity. Due to the potential antioxidant and antihypertensive properties of FSGH2 and FSGH4, further research is needed to explore their possible use as natural supplementary raw materials in food and nutraceutical products.

Biological surfaces with unique wettability in nature have provided an enormous innovation for scientists and engineers. More specifically, materials possessing various wetting properties have drawn considerable attention owing to their promising application prospects. Recently, great efforts have been concentrated on the researches on wetting-induced drag-reduction materials inspired by biology because of their ability to save energy. In this work, the drag-reduction characteristics of the bionic surface with delicate water-trapping microstructures of fish Ctenopharyngodon idellus scales were explored by experimental method. Firstly, the resistance of smooth surface and bionic surface experimental sample at different speeds was carefully tested through the testing system for operation resistance. Then, the contact angle (CA) of fish scale surface was measured by means of the contact angle measuring instrument. It was discovered that the bionic surface created a rewarding drag-reduction effect at a low speed, and the drag-reduction rate significantly displayed a downward trend with the increase in flow speed. Thus, when the rate was 0.66 m/s, the drag-reduction effect was at the optimum level, and the maximum drag reduction rate was 2.805%, which was in concordance with the simulated one. Furthermore, a contact angle (CA) of 11.5° appeared on the fish scale surface, exhibiting fine hydrophilic property. It further manifested the spreading-wetting phenomenon and the higher surface energy for the area of apical of fish scales, which played an important role in drag-reduction performance. This work will have a great potential in the engineering and transportation field.

Influence of various phenolic compounds on physical properties and antioxidant activity of gelatin film from horse mackerel Trachurus japonicus scales was investigated. Tensile strength (TS) of the film was enhanced whereas elongation at break was declined by adding 1% to 5% phenolic compounds. Rutin was the most effective to improve the TS compared to the other tested phenolic compounds including ferulic acid, caffeic acid, gallic acid, and catechin. Gelatin films with the phenolic compounds showed the excellent UV barrier properties. FTIR spectra exhibited that wavenumber of amide-A band of films decreased with formation of hydrogen bonding between amino groups of gelatin and hydroxyl groups of the phenolic compounds. Gelatin film incorporated with rutin which has the largest number of hydroxyl groups among the tested compounds demonstrated the lowest wavenumber for the amide-A peak. It is indicated that hydroxyl groups contained in the phenolic compounds contribute to formation of hydrogen bonds involved in improvement of the mechanical properties of the films. The incorporation of the phenolic compounds with gelatin films also led to the increasing of total phenolic contents and DPPH radical scavenging activities. Thus, it is concluded that phenolic compounds can promote the quality of gelatin film., Practical Application: Properties of gelatin film derived from horse mackerel scales can be improved by adding of phenolic compounds. Phenolic compounds containing a large number of hydroxyl groups should be selected to enhance physical properties of the gelatin film. A biodegradable film prepared from horse mackerel gelatin incorporated with phenolic compounds, which has good physical properties and antioxidant properties, can solve environmental problems caused by synthetic plastic materials., (© 2018 Institute of Food Technologists®.)