Isolation and Comparative Study on the Characterization of Guanidine Hydrochloride Soluble Collagen and Pepsin Soluble Collagen from the Body of Surf Clam Shell (Coelomactra antiquata)

The role of cathepsin L on structural changes of collagen fibers involved in textural deterioration of chilled grass carp (Ctenopharyngodon idella) fillets

BACKGROUND

Textural deterioration is a serious problem in chilled fish flesh. Cysteine proteinases are proposed to participate in disintegration of collagen fibers during this process, while its mechanism remains elusive. In the present study, a cysteine proteinase was purified from grass carp muscle and identified by mass spectrometry, and its effect on structural changes of collagen fibers was investigated.

RESULTS

During storage at 4 °C, cysteine proteinase activity in fillets increased to 1.53-fold at day 5 and maintained a high level later, and this variable was related to a decline in shear force and an increase in drip loss. A 29 kDa cysteine proteinase was purified through ammonium sulfate precipitation and column chromatography, and identified as cathepsin L. Cathepsin L caused collagen fibers to partly disintegrate into fibril bundles and individual fibrils at 48 h, while the triple helical structure of collagen molecules remained stable. Release of soluble proteins and glycosaminoglycans from cathepsin L-treated collagen fibers was time dependent, coinciding with a release of 4.12 ± 0.13% and 8.57 ± 0.03% at 48 h respectively. However, 0.85 ± 0.02% of hydroxyproline was freed from cathepsin L-treated collagen fibers at 48 h. Furthermore, scanning electron microscopy revealed that the inhibitory effect of cathepsin L could retard the destruction of intramuscular connective tissues (IMCTs).

CONCLUSION

These results indicated that cathepsin L might be involved in collagen fiber breakdown by degrading collagen-associated proteoglycans during textural deterioration of grass carp. © 2022 Society of Chemical Industry.

SMRT Sequencing of the Full-Length Transcriptome of the Coelomactra antiquata

Coelomactra antiquata is an important aquatic economic shellfish with high medicinal value. However, because C. antiquata has no reference genome, a lot of molecular biology research cannot be carried out, so the analysis of its transcripts is an important step to study the regulatory genes of various substances in C. antiquata. In the present study, we conducted the first full-length transcriptome analysis of C. antiquata by using PacBio single-molecule real-time (SMRT) sequencing technology. The results identified a total of 39,209 unigenes with an average length of 2,732 bp, 23,338 CDSs, 251 AS events, 9,881 lncRNAs, 20,106 SSRs, and 2,316 TFs. Subsequently, 59.22% (23,220) of the unigenes were successfully annotated, of which 23,164, 18,711, 15,840, 13,534, and 13,474 unigenes could be annotated using NR, Swiss-prot, KOG, GO, and KEGG databases, respectively. This study lays the foundation for the follow-up research of molecular biology and provides a reference for studying the more medicinal value of C. antiquata.

Marine-Derived Collagen as Biomaterials for Human Health

Collagen is a kind of biocompatible protein material, which is widely used in medical tissue engineering, drug delivery, cosmetics, food and other fields. Because of its wide source, low extraction cost and good physical and chemical properties, it has attracted the attention of many researchers in recent years. However, the application of collagen derived from terrestrial organisms is limited due to the existence of diseases, religious beliefs and other problems. Therefore, exploring a wider range of sources of collagen has become one of the main topics for researchers. Marine-derived collagen (MDC) stands out because it comes from a variety of sources and avoids issues such as religion. On the one hand, this paper summarized the sources, extraction methods and characteristics of MDC, and on the other hand, it summarized the application of MDC in the above fields. And on the basis of the review, we found that MDC can not only be extracted from marine organisms, but also from the wastes of some marine organisms, such as fish scales. This makes further use of seafood resources and increases the application prospect of MDC.

Fish Collagen: Extraction, Characterization, and Applications for Biomaterials Engineering

The utilization of marine-based collagen is growing fast due to its unique properties in comparison with mammalian-based collagen such as no risk of transmitting diseases, a lack of religious constraints, a cost-effective process, low molecular weight, biocompatibility, and its easy absorption by the human body. This article presents an overview of the recent studies from 2014 to 2020 conducted on collagen extraction from marine-based materials, in particular fish by-products. The fish collagen structure, extraction methods, characterization, and biomedical applications are presented. More specifically, acetic acid and deep eutectic solvent (DES) extraction methods for marine collagen isolation are described and compared. In addition, the effect of the extraction parameters (temperature, acid concentration, extraction time, solid-to-liquid ratio) on the yield of collagen is investigated. Moreover, biomaterials engineering and therapeutic applications of marine collagen have been summarized.

Factors affecting thermal stability of collagen from the aspects of extraction, processing and modification

Abstract

Collagen, as a thermal-sensitive protein, is the most abundant structural protein in animals. Native collagen has been widely applied in various fields due to its specific physicochemical and biological properties. The beneficial properties would disappear with the collapse of the unique triple helical structure during heating. Understanding thermal stability of collagen is of great significance for practical applications. Previous studies have shown the thermal stability would be affected by the different sources, extraction methods, solvent systems in vitro and modified methods. Accordingly, the factors affecting thermal stability of collagen are discussed in detail in this review.

Graphical abstract