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Nghiên cứu được tiến hành nhằm gắn kết collagen trích ly từ da cá tra (Pangasiidae) lên bề mặt hydroxyapatite (HA) tổng hợp từ xương cá tra làm tăng khả năng ứng dụng trong lĩnh vực y sinh. Sau khi trích ly, collagen được gắn kết lên bề mặt HA thông qua cầu nối glutaraldehyde. Các hạt HA trước tiên gắn kết với 3 – amino propyl triethoxysilane (APTES) tạo nhóm chức amine trên bề mặt. Glutaraldehyde là cầu nối gắn kết HA và collagen thông qua phản ứng giữa nhóm chức amine và aldehyde. Các yếu tố ảnh đến sự gắn kết như nồng độ collagen, pH dung dịch phản ứng, thời gian và nhiệt độ của phản ứng được tiến hành khảo sát. Kết quả thí nghiệm cho thấy nồng độ collagen 1 mg/mL, dung dịch acetic acid hòa tan collagen có pH 3, thời gian phản ứng 3 giờ và nhiệt độ phản ứng 37C là điều kiện thích hợp để tiến hành gắn kết. Ngoài ra, kết quả chụp SEM cho thấy rằng các hạt HA được chế tạo có kích thước khoảng 1.000 nm và bị phủ một lớp collagen sau khi gắn kết.

The present study was to investigate the effects of different salinities (0 (control), 3, 6, 9, 12, 15‰) in striped catfish (Pangasianodon hypophthalmus) at larvae stage. Four-hundred individuals were randomly distributed to each 500-L composite tank (containing 250-L water) in triplicates. After 60 days, fish was sampled to determine survival rate, growth performance, hematological parameters, stress response indicators, and enzymatic activities. The results showed that the survival rate was highest in 6‰ (60.9%) and lowest in 15‰ (1.25%) (p

The effects of temperature on growth performance, survival rate, digestive enzymatic activities, and physiological responses of striped snakehead (Channa striata) at fry stage were evaluated. The study consisted of two trials including (1) determination of temperature threshold and (2) effects of different temperatures (24°C, 27°C (control), 30°C, 33°C and 36°C) on growth performance, survival rate, digestive enzyme activities and physiological parameters of striped snakehead fry stage for 90 days. The growth experiment was conducted in 500-L tank (250-L water) with triplicates. The stocking density was 300 individuals per tank. Striped snakehead at fry stage showed a high tolerance to temperature ranging from 10 to 40ºC. After 90 days, fish reared in 30°C performed the greatest weight and survival rate (13.1±3.12 g/fish and 15.5±4.63%, respectively). The number of red blood cells and hemoglobin concentrations increased with the increase in temperature. It was discovered that different temperatures (from 27 to 36°C) did not significantly influence the number of white blood cells, osmolality, and ion concentration of fish. Glucose and cortisol concentrations increased with temperature rises and peaked in fish reared at 36°C, while temperatures of 30oC and 33oC showed higher digestive enzyme activities. It proves that 30°C is the optimal level for striped snakehead fry rearing.

This study was conducted to incorporate amine functional groups on the surface of hydroxyapatite to enhance its potential application in biomedical materials. Hydroxyapatite particles (HA) were synthesized from striped catfish (Pagasianodon hypophthalmus) bone and surface modified by grafting with (3-aminopropyl)triethoxysilane (APTES). Important factors affected grafting efficiency such as concentration of APTES, water content, reaction temperature and reaction time were studied. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were used to confirm the grafting reaction on HA surfaces. Grafting efficiency was evaluated based on intensity of characteristic absorption peaks of APTES. The experimental results showed that amine functional groups were successfully introduced on HA surface at optimal condition of 0.2 M APTES, 0.75 wt.% water content, at 60°C and 12-hour reaction time.

Nonmammalian collagens have attracted significant attention owing to their potential for use as a source of cell scaffolds for tissue engineering. Since the morphology of collagen fibrils controls cell proliferation and differentiation, its regulation is essential for fabricating scaffolds with desirable characteristics. In this study, we evaluated the effects of the phosphate ion (Pi) concentration on the characteristics of fibrils formed from swim bladder type I collagen (SBC) and skin type I collagen (SC) from the Bester sturgeon. An increase in the Pi concentration decreased the fibril formation rate, promoted the formation of thick fibrils, and increased the thermal stability of the fibrils for both SBC and SC. However, the SBC and SC fibrils exhibited different fibril formation rates, degrees of fibrillogenesis, morphologies, and denaturation temperatures for the same reaction conditions. Finally, by regulating the Pi concentration, various types of SBC and SC fibrils could be coated on cell culture wells, and fibroblasts could be cultured on them. The results showed that thin fibrils enhance fibroblast extension and proliferation, whereas thick fibrils restrain fibroblast extension but orient them in the same direction. The results of this study suggest that SBC fibrils, which exhibit diverse morphologies, are suitable for use as a novel scaffold material, whose characteristics can be tailored readily by varying the Pi concentration.

The objective of this study was to assess the nature of the collagens from the Amur sturgeon to determine its possibility as a potential collagen source for biomedical applications. From a sturgeon (1.22 kg), 6.0 g (dry wt) of skin collagen (SC), 4.1 g of swim bladder collagen (SBC), and 0.4 g of notochord collagen (NC) were obtained. SC and SBC were characterized as type I, and NC as type II collagen. Denaturation temperatures of SC, SBC, and NC were calculated as 28.5, 30.5, and 33.5 °C, respectively. Gene expression of the type I procollagen α2 chain of Amur sturgeon (ascol1a2) was specifically higher than ascol1a1 expression in the swim bladder, suggesting a unique composition of α chains in this organ. SC and SBC had better abilities of fibril formation with unique higher-order structures compared with porcine type I collagen. The maximum transition temperature (Tm) of reassembled fibrils formed in a buffer solution containing NaCl at 0 and 140 mM was 34.4 °C and 38.9 °C in SC, and 40.1 °C and 40.7 °C in SBC, respectively. These characteristic features suggested that sturgeon collagens could be used in the biomedical industries in future applications.

Both female and male sea urchins accumulate the major yolk protein (MYP) in the nutritive phagocytes of immature gonads before gametogenesis. Additionally, the most abundant protein in the coelomic fluids of both sexes is MYP. In females, MYP in the coelomic fluid is taken up by the nutritive phagocytes and then transported into growing oocytes. In this study, quantitative changes of MYP in the coelomic fluid of both sexes were examined during the reproductive cycle of the wild sea urchin, Mesocentrotus nudus. In females but not males, positive correlation between MYP level and the gonadosomatic index was observed. These results indicate that MYP in the coelomic fluid is suitable as a biomarker of the onset of puberty and progression of maturity in female sea urchins.

Non-mammalian collagens have attracted increasing attention for industrial and biomedical use. We have therefore evaluated extraction conditions and the biochemical properties of collagens from aquacultured sturgeon. Pepsin-soluble type I and type II collagen were respectively extracted from the skin and notochord of bester sturgeon by-products, with yields of 63.9 ± 0.19% and 35.5 ± 0.68%. Collagen extraction efficiency was improved by an alkaline pretreatment of the skin and notochord (fewer extraction cycles were required), but the final yields decreased to 56.2 ± 0.84% for type I and 31.8 ± 1.13% for type II. Alkaline pretreatment did not affect the thermal stability or triple-helical structure of both types of collagen. Types I and II collagen formed re-assembled fibril structures in vitro, under different conditions. Alkaline pretreatment slowed down the formation of type I collagen fibrils and specifically inhibited the formation of thick fibril-bundle structures. In contrast, alkaline pretreatment did not change type II collagen fibril formation. In conclusion, alkaline pretreatment of sturgeon skin and notochord is an effective method to accelerate collagen extraction process of types I and II collagen without changing their biochemical properties. However, it decreases the yield of both collagens and specifically changes the fibril-forming ability of type I collagen.