Inhibitory effect of pre-gelatinized dialdehyde starch on heat-induced deterioration of sea cucumber

BACKGROUND

This study sought to investigate the inhibitory effect of pre-gelatinized dialdehyde starch (P-DAS) on the deterioration of sea cucumber during high-temperature sterilization.

RESULTS

It was found that pre-gelatinization reduced crystallinity and average molecular weight of dialdehyde starch (DAS), exposed free aldehyde groups, improved the solubility, and unified the particle sizes. According to the texture profiles of sea cucumber, the crosslinking power of P-DAS was higher than that of DAS. The results of free amino content, total soluble substance, water retention, water distribution, relaxation time and scanning electron microscopy all showed that the crosslinking effect was dose-dependent on crosslinking agent.

CONCLUSION

These results have proved that large molecules such as P-DAS, when properly handled, could also efficiently enter collagen hydrogels and perform crosslinking, providing reference for the development of new protein food stabilizing agents. © 2022 Society of Chemical Industry.

The Bioactivity Prediction of Peptides from Tuna Skin Collagen Using Integrated Method Combining In Vitro and In Silico

The hydrolysates and peptide fractions of bigeye tuna (Thunnus obesus) skin collagen have been successfully studied. The hydrolysates (HPA, HPN, HPS, HBA, HBN, HBS) were the result of the hydrolysis of collagen using alcalase, neutrase, and savinase. The peptide fractions (PPA, PPN, PPS, PBA, PBN, PBS) were the fractions obtained following ultrafiltration of the hydrolysates. The antioxidant activities of the hydrolysates and peptide fractions were studied using the DPPH method. The effects of collagen types, enzymes, and molecular sizes on the antioxidant activities were analyzed using profile plots analysis. The amino acid sequences of the peptides in the fraction with the highest antioxidant activity were analyzed using LC-MS/MS. Finally, their bioactivity and characteristics were studied using in silico analysis. The hydrolysates and peptide fractions provided antioxidant activity (6.17-135.40 µmol AAE/g protein). The lower molecular weight fraction had higher antioxidant activity. Collagen from pepsin treatment produced higher activity than that of bromelain treatment. The fraction from collagen hydrolysates by savinase treatment had the highest activity compared to neutrase and alcalase treatments. The peptides in the PBN and PPS fractions of <3 kDa had antidiabetic, antihypertensive and antioxidant activities. In conclusion, they have the potential to be used in food and health applications.

Role of Platelet-Derived Growth Factor on the Fibrosis Process in Thyroid Carcinoma: Evaluation by Shear Wave Elastography

OBJECTIVES

We aimed to determine the correlation between fibrosis and elastic values in papillary thyroid carcinoma (PTC) by shear wave elastography and to evaluate the effect of platelet-derived growth factor (PDGF) on the fibrosis process.

METHODS

Small interfering RNA (siRNA)-PDGF and normal BCPAP cell lines were injected subcutaneously into the backs of nude mice. The elastic values of all tumors were measured by shear wave elastography. The content of collagen fibers and the expression of PDGF and type IV collagen (COL4) were evaluated by Masson staining and western blotting.

RESULTS

There were 32 tumors in the control group and 30 tumors in the siRNA-PDGF group. The tumors were divided into 4 subgroups based on maximum diameters of the tumors. The mean elastic values ± SD (E_mean , 29.79 ± 11.04 kPa; E_min , 16.98 ± 7.51 kPa, E_max , 39.99 ± 15.30 kPa; and SD, 5.92 ± 2.00 kPa) in the siRNA-PDGF group were lower than in the control group (E_mean , 35.73 ± 18.49 kPa; E_min , 23.65 ± 14.92 kPa, E_max , 45.73 ± 22.88 kPa; and SD, 6.02 ± 3.38 kPa). The content of collagen fibers and the expression of platelet-derived growth factor B (PDGFB) and COL4 proteins in the siRNA-PDGF group were lower than in the control group (11.43% ± 6.99% and 19.80% ± 11.70%; P = .010; 0.14 ± 0.06 and 0.27 ± 0.10; P = .002; and 0.11 ± 0.06 and 0.15 ± 0.07; P = .101). The elastic values, collagen fiber content, and PDGFB and COL4 in the 4 subgroups gradually increased with the maximum diameter of tumors.

CONCLUSIONS

There was a positive correlation among PDGF, tumor stiffness, and fibrosis in the growth of PTC. Thus, PDGF might play an important role in the development of PTC.

Colloidal Gold--Collagen Protein Core--Shell Nanoconjugate: One-Step Biomimetic Synthesis, Layer-by-Layer Assembled Film, and Controlled Cell Growth

The biogenic synthesis of biomolecule-gold nanoconjugates is of key importance for a broad range of biomedical applications. In this work, a one-step, green, and condition-gentle strategy is presented to synthesize stable colloidal gold-collagen core-shell nanoconjugates in an aqueous solution at room temperature, without use of any reducing agents and stabilizing agents. It is discovered that electrostatic binding between gold ions and collagen proteins and concomitant in situ reduction by hydroxyproline residues are critically responsible for the formation of the core-shell nanoconjugates. The film formed by layer-by-layer assembly of such colloidal gold-collagen nanoconjugates can notably improve the mechanical properties and promote cell adhesion, growth, and differentiation. Thus, the colloidal gold-collagen nanoconjugates synthesized by such a straightforward and clean manner, analogous to a biomineralization pathway, provide new alternatives for developing biologically based hybrid biomaterials toward a range of therapeutic and diagnostic applications.