Long-term changes in zooplankton and its relationship with squid, Todarodes pacificus, catch in Japan/East Sea

Long‐term change in zooplankton biomass and composition of major zooplankton assemblages was studied with a focus on climate change and squid catch in the Japan/East Sea. This study deals with data sets of zooplankton biomass, abundance of major zooplankton assemblages, and sea surface temperature (SST) obtained during the period from 1965 to 1998, and the catch of squid, Todarodes pacificus, from 1978 to 1998. Based on its physical characteristics, the study area was divided into two subregions, a northern and southern region. The SST during the winter and spring (February and April) steadily increased after the late 1980s in the southern region. On the other hand, the northern region did not have a warm winter and had higher interannual fluctuations. Zooplankton biomass also showed an increasing trend and major zooplankton assemblages have shifted in their composition since the early 1990s. The northern region exhibited a greater increasing trend than the southern region in zooplankton biomass. Macrozooplankton such as chaethognaths, euphausiids and amphipods gradually increased after the early 1990s. In the Japan/East Sea, squid catches increased continuously after the early 1990s. The squid catch for the autumn of year n is significantly associated with the zooplankton biomass collected in October and December of year n ? 1 (r=0.864 in the northern region and r=0.818 in the southern region, P < 0.001) and macrozooplankton, especially euphausiids (r=0.578 in the northern region and r=0.840 in the southern region, P < 0.05) and amphipods (r=0.695 in the northern region and r=0.648 in the southern region, P < 0.05).     

Characterization of 38 kDa and 42 kDa chitinase isozymes from the liver of Japanese common squid Todarodes pacificus

ABSTRACT: Characterization was investigated on the 38 kDa and 42 kDa chitinase (EC3.2.1.14) isozymes from the liver of Japanese common squid Todarodes pacificus . Optimum pH toward colloidal chitin was observed at pH 3.0 for the 38 kDa chitinase, and pH 3.0 and 9.0 for the 42 kDa chitinase. K _m and k _cat of the 38 kDa and 42 kDa chitinases toward a longer substrate, glycol chitin, were 0.071 mg/mL and 1.22/s, and 0.074 mg/mL and 0.196/s, respectively. Alternatively, strong substrate inhibition of both chitinases were observed toward a short substrate, N -acetylchitopentaose (GlcNAc₅). Both chitinases decomposed not only chitin but also chitosan (D. A. 95%). The cleavage pattern and reaction rate were investigated using N -acetylchitooligosaccharides (GlcNAc_n, n  = 2–6). Both chitinases hydrolyzed GlcNAc_n ( n  = 4,5, and 6). The release of GlcNAc was not observed. The speed of the reaction was observed to be in the following order: GlcNAc₄ > GlcNAc₅ > GlcNAc₆ for the 38 kDa chitinase, and GlcNAc₆ > GlcNAc₅ > GlcNAc₄ for the 42 kDa chitinase. Both the chitinases released p -nitrophenol from p -nitrophenyl GlcNAc_n ( n  = 2, 3, and 4). N-terminal amino acid sequences of the 38 kDa and 42 kDa chitinases were YLLSXYFTNWSQYRPGAGKYFPQNI and EYRKVXYYTNWSQYREVPAKFFPEN, respectively.     

基于神经网络的北太平洋柔鱼渔场预报

根据1998-2004年6-11月份我国鱿钓生产数据（月份、作业船数、经纬度和日产量）以及对应的海洋环境因子数据,即5 m水层的海水温度、46 m水层的海水温度、112 m水层的海水温度、317 m水层的海水温度、叶绿素a含量以及海平面高度距平值等,以经标准化后的单位捕捞努力量渔获量（CPUE）作为中心渔场指标,采用多种BP神经网络预报模型,对北太平洋柔鱼渔场进行了分析与比较。通过对13种神经网络预报模型的比较,以及实际CPUE的验证,以拟合残差最小的预报模型作为最优预报模型,认为结构为9 7 1的BP神经网络模型相对误差仅为0.008 570,可作为北太平洋柔鱼渔场的预报模型。     

Customizing Properties of β-Chitin in Squid Pen (Gladius) by Chemical Treatments

The squid pen (gladius) from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications.     

我国远洋鱿钓渔业市场演进路径与产业发展对策

远洋鱿钓渔业是我国远洋渔业的重要组成部分,也是我国发展规模最大的远洋渔业产业。从捕捞生产规模角度来看,我国远洋鱿钓渔业20多年的发展实践可以划分为三个阶段:起步与规模扩张阶段、规模调整阶段和产业调整提升阶段。分析了市场从外向型向内外兼顾型、产品加工由低层次向多层次平衡发展的远洋鱿钓渔业市场演进路径。结合对舟山等地的调研分析认为,我国远洋鱿钓产业主要存在捕捞量与加工市场需求量不协调、国内外市场依赖程度不协调、个别利益与产业整体利益之间不协调三大制约瓶颈。提出了通过加强对公海鱿鱼渔场的调查、加快拓展国内鱿鱼消费市场规模、进一步提升鱿鱼产品深加工能力、建立紧密型行业服务组织的对策建议。     

Diamond Squid (Thysanoteuthis rhombus)-Derived Chondroitin Sulfate Stimulates Bone Healing within a Rat Calvarial Defect

Chondroitin sulfate (CS) has been suggested to be involved in bone formation and mineralization processes. A previous study showed that squid-derived CS (sqCS) has osteoblastogenesis ability in cooperation with bone morphogenetic protein (BMP)-4 in vitro. However, in vivo, osteogenic potential has not been verified. In this study, we created a critical-sized bone defect in the rat calvaria and implanted sqCS-loaded gelatin hydrogel sponges (Gel) into the defect with or without BMP-4 (CS/BMP/Gel and CS/Gel, respectively). At 15 weeks, bone repair rate of CS/Gel-treated defects and CS/BMP/Gel-treated defects were 47.2% and 51.1%, respectively, whereas empty defects and defects with untreated sponges showed significantly less bone ingrowth. The intensity of von Kossa staining of the regenerated bone was less than that of the original one. Mineral apposition rates at 9 to 10 weeks were not significantly different between all treatment groups. Although bone repair was not completed, sqCS stimulated bone regeneration without BMP-4 and without external mesenchymal cells or preosteoblasts. Therefore, sqCS is a promising substance for promotion of osteogenesis.     

Utilization of Marine Waste to Obtain β-Chitin Nanofibers and Films from Giant Humboldt Squid Dosidicus gigas

β-chitin was isolated from marine waste, giant Humboldt squid Dosidicus gigas, and further converted to nanofibers by use of a collider machine under acidic conditions (pH 3). The FTIR, TGA, and NMR analysis confirmed the efficient extraction of β-chitin. The SEM, TEM, and XRD characterization results verified that β-chitin crystalline structure were maintained after mechanical treatment. The mean particle size of β-chitin nanofibers was in the range between 10 and 15 nm, according to the TEM analysis. In addition, the β-chitin nanofibers were converted into films by the simple solvent-casting and drying process at 60 °C. The obtained films had high lightness, which was evidenced by the CIELAB color test. Moreover, the films showed the medium swelling degree (250–290%) in aqueous solutions of different pH and good mechanical resistance in the range between 4 and 17 MPa, depending on film thickness. The results obtained in this work show that marine waste can be efficiently converted to biomaterial by use of mild extractive conditions and simple mechanical treatment, offering great potential for the future development of sustainable multifunctional materials for various industrial applications such as food packaging, agriculture, and/or wound dressing.     

Improvement of Cold and Thermally Induced Gelation of Giant Squid (Dosidicus gigas) Surimi

Depending on the season of capture, giant squid (Dosidicus gigas) surimi processed by isoelectric precipitation presents low gel strength. Addition of microbial transglutaminase (MTGase) and application of high isostatic pressure (300 MPa) to improve physicochemical properties were assayed for purposes of making “suwari” gels and heated gels for use in restructured products which have a raw or cooked appearance. The physicochemical properties of both pressurized and unpressurized gels induced by application of 30°C/1 h improved when MTGase was added. In contrast, addition of MTGase was less effective in gels subsequently heated at 90°C/30 min after 30°C/1 h. High pressure treatment for 30 min at 300 MPa and 15°C helped to produce gels with better mechanical and water binding properties, whether treated for 30°C/1 h only or for 30°C/1 h plus 30-min heat treatment at 90°C. High pressure treatment also reduced lightness.     

Physiochemical and Textural Alterations in Indian Squid (Loligo duvauceli) Mantle During Frozen Storage and Cooking

Textural variations in squid mantle and the role of proteins on texture during frozen storage and cooking were investigated. Myofibrillar protein (62.36%) and pepsin soluble collagen (10.70%) accounted for the major fraction of total protein (22.17%). The histochemistry of mantle tissue showed a mesh-like arrangement of myofibrillar proteins with a collagenous dermal layer and feebly passing collagen through myotome bundles. Texture profile analysis of unfrozen mantle suggested the first phase of hardening at 50°C with hardness 1 (H1) of 11.53 kgf and hardness 2 (H2) of 9.68 kgf; and the second phase of hardening with optimal texture and maximum juiciness at 70°C (H1, 8.11 kgf; H2, 7.13 kgf) that varied with extended frozen storage. Increased frozen storage and cooking led to protein denaturation and formation of new low molecular weight proteins as evidenced in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE); these possibly influenced the functional and microstructural properties of the tissue.     

鸢乌贼酶解产物的抗氧化稳定性与功能特性

以鸢乌贼(Symplectoteuthis oualaniensis)胴体为原料,采用木瓜蛋白酶进行酶解,比较了酶解液中不同分子量组分的抗氧化特性,探讨了温度、p H和光照对其抗氧化活性的影响,以及其功能特性(包括乳化性和乳化稳定性、起泡性和泡沫稳定性、吸水性、持水性和吸油性等)。结果表明,鸢乌贼酶解产物具有一定的耐热性,在酸性偏中性的环境中能较好地保持其抗氧化活性,日光照射会降低其抗氧化能力。此外,酶解产物还具有较强的乳化性、起泡性、吸水吸油能力等功能特性。