Contribution of the polymerization of protein by disulfide bonding to increased gel strength of walleye pollack surimi gel with preheating time     

Mohammed Ismail Hossain  Yoshiaki Itoh  Katsuji Morioka  Atsushi Obatake 《Fisheries Science》2001,67(4):710-717

ABSTRACT: To clarify the contribution of polymerization of myosin heavy chain (MHC) by disulfide bonding to increased gel strength of cooked gel via preheating, the pastes of walleye pollack surimi (SS and C grades) were preheated at 25°C and 40°C for a variety of hours prior to heating at 80°C for 20 min. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns of cooked gels were analyzed with and without reducing the samples, which were solubilized in 8 M urea–2% SDS solution. The formation of polymers by disulfide bonding in cooked gels was almost constant in each of the SS and C grade surimi gels despite the period of preheating. Therefore, it was suggested that polymerization by disulfide bonding occurred during cooking at 80°C and not during preheating.  相似文献   

Inhibiting effect of polymerization and degradation of myosin heavy chain during preheating at 30°C and 50°C on the gel-forming ability of walleye pollack surimi     

Mohammed Ismail Hossain  Yoshiaki Itoh  Katsuji Morioka  Atsushi Obatake 《Fisheries Science》2001,67(4):718-725

ABSTRACT: To confirm the contribution of polymerization and degradation of myosin heavy chain (MHC) during preheating to the gel-forming ability of fish meat paste, walleye pollack surimi paste was preheated at 30°C and 50°C prior to heating at 80°C in the presence of various inhibitors. At 30°C, ethyleneglycol bis(2-aminoethyl ether) -N,N,N ', N '-tetraacetic acid (EGTA) and ethylenediaminetetraacitic acid (EDTA) inhibited gel formation as well as the polymerization of MHC, whereas dithiothreitol (DTT) and leupeptin promoted gel formation, which was accompanied by the enhancement of MHC polymerization and decreased MHC degradation, respectively. At 50°C, leupeptin inhibited MHC degradation and improved gel strength, whereas EGTA, EDTA and DTT had no effect on MHC polymerization and degradation and did not affect gel formation. The results demonstrate that the gel strength of cooked gel (80°C) is not affected by preheating at 30°C and 50°C and does not inhibit polymerization and degradation. Results suggest that the gel strength of cooked gel is dependent on the polymerization and degradation of MHC during preheating.  相似文献   

A simple method for selection of cumulus-oocyte complexes from bovine ovaries by sedimentation with percoll     

Yotsushima K  Shimizu M  Kon H  Izaike Y 《The Journal of reproduction and development》2007,53(4):971-976

Selection of bovine cumulus-oocyte complexes (COCs) for in vitro embryo production (IVP) is generally based on the morphological characteristics of the cumulus cells surrounding the oocytes and the ooplasm under microscopic observation. The purpose of this study was to examine a simple method for selection of COCs by sedimentation with Percoll solutions. COCs were aspirated from ovaries derived from a local slaughterhouse, and the COCs were classified by the morphology of their cumulus cell layers, as follows: Class A, compact and thick; Class B, compact but thin; Class C, partially denuded and thin; and Class D, denuded. Percoll solutions were prepared by diluting Percoll to 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5 and 30% solutions, respectively. COCs were placed on the surface of the Percoll solution for 3 min, and the precipitated COCs were transferred to stepwise high density solution. The percentage of Percoll solution just before buoyancy was considered to the specific sedimentary value of the COC and oocyte. The mean sedimentary value of Class A COCs was higher than those of the other classes (P<0.01). The mean sedimentary values of denuded oocytes from Classes A and B were higher than those from Classes C and D (P<0.01). Our results show that sedimentation of COCs and denuded oocytes was generally related to the morphological quality of the COCs, although the sedimentary values ranged widely for one class of COCs and oocytes. The Percoll method can be used for simple selection of COCs.  相似文献   

Melatonin protects the integrity of granulosa cells by reducing oxidative stress in nuclei,mitochondria, and plasma membranes in mice     

Manabu TANABE  Hiroshi TAMURA  Toshiaki TAKETANI  Maki OKADA  Lifa LEE  Isao TAMURA  Ryo MAEKAWA  Hiromi ASADA  Yoshiaki YAMAGATA  Norihiro SUGINO 《The Journal of reproduction and development》2015,61(1):35-41

Melatonin protects luteinized granulosa cells (GCs) from oxidative stress in the follicle during ovulation. However, it is unclear in which cellular components (e.g., nuclei, mitochondria, or plasma membranes) melatonin works as an antioxidant. GCs from immature (3 wks) ICR mice were incubated with hydrogen peroxide (H2O2; 0.01, 0.1, 1, 10 mM) in the presence or absence of melatonin (100 μg/ml) for 2 h. DNA damage was assessed by fluorescence-based immunocytochemistry using specific antibodies for 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative guanine base damage in DNA, and for histone H2AX phosphorylation (γH2AX), a marker of double-strand breaks of DNA. Mitochondrial function was assessed by the fluorescence intensity of MitoTracker Red probes, which diffuse across the membrane and accumulate in mitochondria with active membrane potentials. Lipid peroxidation of plasma membranes was analyzed by measuring hexanoyl-lysine (HEL), a oxidative stress marker for lipid peroxidation. Apoptosis of GCs was assessed by nuclear fragmentation using DAPI staining, and apoptotic activities were evaluated by caspase-3/7 activities. H2O2 treatment significantly increased the fluorescence intensities of 8-OHdG and γH2AX, reduced the intensity of MitoTracker Red in the mitochondria, increased HEL concentrations in GCs, and enhanced the number of apoptotic cells and caspase-3/7 activities. All these changes were significantly decreased by melatonin treatment. Melatonin reduced oxidative stress-induced DNA damage, mitochondrial dysfunction, lipid peroxidation, and apoptosis in GCs, suggesting that melatonin protects GCs by reducing oxidative stress of cellular components including nuclei, mitochondria, and plasma membranes. Melatonin helps to maintain the integrity of GCs as an antioxidant in the preovulatory follicle.  相似文献   

Oleosome-Associated Protein of the Oleaginous Diatom Fistulifera solaris Contains an Endoplasmic Reticulum-Targeting Signal Sequence     

Yoshiaki Maeda  Yoshihiko Sunaga  Tomoko Yoshino  Tsuyoshi Tanaka 《Marine drugs》2014,12(7):3892-3903

Microalgae tend to accumulate lipids as an energy storage material in the specific organelle, oleosomes. Current studies have demonstrated that lipids derived from microalgal oleosomes are a promising source of biofuels, while the oleosome formation mechanism has not been fully elucidated. Oleosome-associated proteins have been identified from several microalgae to elucidate the fundamental mechanisms of oleosome formation, although understanding their functions is still in infancy. Recently, we discovered a diatom-oleosome-associated-protein 1 (DOAP1) from the oleaginous diatom, Fistulifera solaris JPCC DA0580. The DOAP1 sequence implied that this protein might be transported into the endoplasmic reticulum (ER) due to the signal sequence. To ensure this, we fused the signal sequence to green fluorescence protein. The fusion protein distributed around the chloroplast as like a meshwork membrane structure, indicating the ER localization. This result suggests that DOAP1 could firstly localize at the ER, then move to the oleosomes. This study also demonstrated that the DOAP1 signal sequence allowed recombinant proteins to be specifically expressed in the ER of the oleaginous diatom. It would be a useful technique for engineering the lipid synthesis pathways existing in the ER, and finally controlling the biofuel quality.  相似文献   

Structure of Fucoidan from Brown Seaweed Turbinaria ornata as Studied by Electrospray Ionization Mass Spectrometry (ESIMS) and Small Angle X-ray Scattering (SAXS) Techniques     

Thuy Thi Thu Thanh  Van Thi Thanh Tran  Yoshiaki Yuguchi  Ly Minh Bui  Tai Tien Nguyen 《Marine drugs》2013,11(7):2431-2443

The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation.  相似文献   

A new dibenzoylhydrazine with insecticidal activity against Anopheles mosquito larvae     

Evangelia Morou  Manolis Lirakis  Nena Pavlidi  Moises Zotti  Yoshiaki Nakagawa  Guy Smagghe  John Vontas  Luc Swevers 《Pest management science》2013,69(7):827-833

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An econometric estimation of Japanese shrimp supply and demand during the 1990s     

Saowanee Traesupap  Yoshiaki Matsuda  Hidenori Shima 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):215-221

Abstract

A simultaneous‐equation model of the supply and demand of shrimp in Japan is constructed, and sensitivity analyses are conducted to measure the effects of changing exchange rates and the stock holdings of shrimp. Using monthly statistics from January 1990 to December 1997, the Japanese own‐price elasticity of supply is found to be inelastic and has a less important effect than the beginning stocks factor. The Japanese demand for shrimp is also found to be price‐and income‐inelastic. The beginning of stock holdings is more sensitive to Japanese shrimp demand than the import price and income. The result of seasonality analyses shows that Japanese shrimp demand also depends on cultural factors.  相似文献   

Non-steroidal ecdysteroid agonist chromafenozide: Gene induction activity, cell proliferation inhibition and larvicidal activity     

Hadi Mosallanejad  Luc Swevers  Yoshiaki Nakagawa 《Pesticide biochemistry and physiology》2008,92(2):70-76

The activity profile of the most recent commercial non-steroidal ecdysteroid agonist chromafenozide (ANS-118), was evaluated on a comparative basis to methoxyfenozide (RH-2485) that is to date the most potent commercial agonist against Lepidoptera. This was done first at the molecular and cellular level regarding its induction activity of an ecdysteroid-responsive reporter gene and its cell proliferation inhibition activity, and subsequently at the level of larvicidal toxicity. For in vitro experiments three ecdysteroid-responsive insect cell lines were used: Drosophila melanogaster (Diptera) S2 cells, Bombyx mori (Lepidoptera) Bm5 cells and Spodoptera exigua (Lepidoptera) Se4 cells. The in vivo toxicity was scored against two major lepidopteran pests in the world, the beet armyworm S. exigua and the cotton leafworm Spodoptera littoralis. In vitro results revealed that chromafenozide and methoxyfenozide are highly potent against lepidopteran cells compared to dipteran cells, supporting the lepidopteran-specificity of these compounds. Interestingly, in the reporter gene induction experiments and proliferation inhibition experiments, a slightly higher efficacy was observed in S2 compared to Bm5 cells at high concentrations of chromafenozide and methoxyfenozide. Our analysis shows the high potency and efficacy of the chromafenozide compound as an ecdysteroid agonist towards lepidopteran insects at a level that is similar to methoxyfenozide.  相似文献   

Brown root rot of Russell prairie gentian caused by Subplenodomus drobnjacensis     

Toru Kondo  Mamoru Satou  Toshiyuki Morikawa  Yoshiaki Chikuo 《Journal of General Plant Pathology》2014,80(1):99-102

Brown root rot of Russell prairie gentian was observed in the Aomori Prefecture, Japan in April 2011. The fungal isolate from the diseased root was identified as Subplenodomus drobnjacensis on the basis of its morphological characteristics and nucleotide sequences. The isolate induced similar root rot symptoms when inoculated in healthy Russell prairie gentian plants. We proposed the name “brown root rot” for this disease.  相似文献