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Wang L.,Ocean University of China | Liu Z.,Ocean University of China | Zhao Y.,Ocean University of China | Dong S.,Ocean University of China | And 2 more authors.
Journal of Food Science and Technology | Year: 2015

Three freezing-point regulators (glycine, sodium chloride and D-sorbitol) were employed to optimize thermophysical properties of Pacific white shrimp (Litopenaeus vannamei) using response surface methodology (RSM). The independent variables were glycine content (0.250–1.250 %), sodium chloride content (0.500–2.500 %) and D-sorbitol content (0.125–0.625 %) and analysis of variance showed that the effects of glycine, sodium chloride and D-sorbitol on the thermophysical properties were statistically significant (P < 0.05). The coefficient of determination, R2 values for initial freezing point (Ti), unfreezable water mass fraction (Wu), apparent specific heat (Capp) and Enthalpy (H) were 0.896 ~ 0.999. The combined effects of these independent variables on Ti, Wu, Capp and H were investigated. The results indicated that Ti, Capp and H varied curvilinearly with increasing of glycine, sodium chloride and D-sorbitol content whereas Wu increased nearly linearly. Based on response plots and desirability functions, the optimum combination of process variables for Pacific white shrimp previously treated with freezing-point regulators were 0.876 % for glycine content, 2.298 % for sodium chloride content and 0.589 % for D-sorbitol content, correspondently the optimized thermophysical properties were Ti, − 5.086 °C; Wu, 17.222 %; Capp, 41.038 J/g °C and H, 155.942 J/g, respectively. Briefly, the application of freezing-point regulators depressed Ti and obtained the optimum Wu, Capp and H, which would be obviously beneficial for the exploitation of various thermal processing and food storage. © 2014, Association of Food Scientists & Technologists (India).

Yang H.,Ocean University of China | Yang H.,Zhejiang Marine Development Research Institute | Zeng M.,Ocean University of China | Dong S.,Ocean University of China | And 2 more authors.
Chinese Journal of Oceanology and Limnology | Year: 2010

In this study, we evaluated the anti-proliferative activity of phlorotannins derived from brown algae Laminaria japonica Aresch extracts on the human hepatocellular carcinoma cell (BEL-7402) and on murine leukemic cells (P388) by MTT assay. Cells were incubated with 100 μg/mL of the phlorotannin extract (PE) for 48 h. The inhibitory rate of PE on BEL-7402 and P388 cells was 30.20±1.16% and 43.44±1.86%, respectively, and the half-inhibitory concentration of PE (IC 50) on P388 and BEL-7402 cells was 120 μg/mL and >200 μg/mL, respectively. Microscopic observation shows that the morphologic features of tumor cells treated with PE and 5-fluorouracil are markedly different from the normal control group. The inhibitory rate of fraction A 2 isolated from PE by sephadex LH-20 for BEL-7402 and P388 cells at the sample concentration of 70.42 μg/mL was 61.96±7.02% and 40.47±8.70%, respectively. The apoptosis peak for fraction A 2 was the most profound of all fractions used in the flow cytometry assay. The results indicate that the anti-proliferative of this algal extract is associated with the total phlorotannin content. © 2010 Chinese Society for Oceanology and Limnology, Science Press and Springer Berlin Heidelberg.

Zhang X.,Zhejiang GongShang University | Zhang X.,Zhejiang Marine Fisheries Research Institute | Zheng B.,Zhejiang Marine Development Research Institute | Zhang H.,Zhejiang GongShang University | And 2 more authors.
Journal of Separation Science | Year: 2011

Methyl-3-quinoxaline-2-carboxylic acid (MQCA) is the last major remaining detectable metabolite of Olaquindox in animal tissue. A rapid, sensitive and specific ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the detection and quantification of MQCA in fish tissue using deuterated quinoxaline-2-carboxylic acid (d 4-QCA) as internal standard. Various parameters affecting sample preparation, LC separation and MS/MS detection were investigated, and the optimal conditions concerned were determined. Fish tissue samples were subject to hydrochloric acid hydrolysis followed by Oasis MAX solid-phase extraction clean-up; analysis was performed using UPLC coupled to electrospray MS/MS. The chromatographic separation was achieved in less than 5 min. The limit of detection and the limit of quantification were 0.1 and 0.25 ng/g, respectively. The average recoveries of MQCA, spiked at levels of 0.25-50.0 ng/g, were from 92.7 to 104.3%. The relative standard deviation values were <6%. The validated method was successfully applied to analyze 60 batch samples collected from the local market. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fu W.,Zhejiang Marine Development Research Institute | Fu W.,CAS Qingdao Institute of Oceanology | Shuai L.,Qingdao University | Yao J.,CAS Qingdao Institute of Oceanology | And 3 more authors.
Plant Molecular Biology Reporter | Year: 2010

Heat shock protein 70 (Hsp70) is one of the important members of heat shock protein (Hsp) families and plays essential roles in folding nascent protein, translocation, refolding denatured protein, protein degradation, adverse stress resistance, and so on. In this study, homologous cloning coupled with the rapid amplification of cDNA ends was used to clone full-length cytosolic heat shock protein 70 of Enteromorpha prolifera (designed as EPHsp70). Bioinformatics was used to analyze structural feature, homologous relationship, and phylogenetic position of EPHsp70. The full length of EPHsp70 cDNA was 2,265 bp, with a 5′ untranslated region of 65 bp, a 3′ untranslated region of 217 bp, and an open-reading frame of 1,983 bp encoding a polypeptide of 660 amino acids with an estimated molecular weight of 71.39 kDa and an estimated isoelectric point of 5.03. EPHsp70 had five degenerate repeats of tetrapeptide GGMP and three typical Hsp70 signature motifs. The C-terminus amino acid sequence of cytosolic EPHsp70 was EEVD, and the conservation of EPHsp70 of N-terminus was higher than that of C-terminus. The homology between EPHsp70 and the cytosolic Hsp70s of other algae and land plants was more than 70%. © Springer-Verlag 2010.

Fu W.,Zhejiang Marine Development Research Institute | Zhang F.,Zhejiang Ocean University | Liao M.,Zhejiang Marine Development Research Institute | Liu M.,Zhoushan Fisheries Research Institute | And 3 more authors.
Fish and Shellfish Immunology | Year: 2013

Heat shock protein 70s (Hsp70s) play important roles in resisting environmental stresses and stimulating innate immune system. To understand the immune defense mechanisms of Scylla serrata, a full-length cytosolic Hsp70 cDNA of S. serrata (designated as SSHsp70) was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) coupled with rapid amplification of cDNA ends (RACE). The full-length of SSHsp70 cDNA was 2235 bp, with a 5' untranslated region of 105 bp, a 3' untranslated region of 174 bp, and an open reading frame of 1956 bp encoding a polypeptide of 651 amino acids with an estimated molecular mass of 71.3 kDa and an estimated isoelectric point of 5.55. The cloned SSHsp70 belonged to a cytosolic Hsp70 family. Three typical Hsp70 signature motifs were detected in SSHsp70 by InterPro analysis. Quantitative PCR (qPCR) was used to detect tissue distribution and mRNA expression levels of SSHsp70 under different stress conditions. The obviously high levels of SSHsp70 transcript were in hemocyte, heart, hepatopancreas and gill, whereas low levels were detected in muscle, eyestalk, stomach, and gut. In different temperature treatments, the expression levels of SSHsp70 in low or high temperatures were higher than those in temperate temperature. In pathogen challenge treatments, the mRNA expression level of SSHsp70 reached a maximum level after 18 h and then dropped progressively. In different salt concentration treatments, the mRNA expression level of SSHsp70 had a minimum level at 25‰ salt concentration and high expression levels at high or low salt concentration. In different nitrite concentration treatments, the mRNA expression level of SSHsp70 increased progressively with the increase of nitrite concentration. The results confirmed Hsp70 could be used as a tool for evolution and phylogenetic analysis, a kind of potential biomarker, and a disease resistance factor used in application. © 2013 Elsevier Ltd.

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