高效液相色谱-原子荧光光谱法分析鱼肌中的总硒和形态硒

硒是人体必需的15种营养素之一,人体内不同形态硒的生物活性存在明显差异,鱼类是含硒量较高的动物,是人体摄入硒的重要来源,因此准确测试鱼肌中总硒和形态硒含量具有重要的意义。将鱼肌样品消解,采用原子荧光光谱法对消解液进行分析,总硒浓度在0~10μg/L内线性关系良好,标准曲线相关系数大于0.999,检出限为0.09μg/L,相对标准偏差(RSD)为0.77%,加标回收率为104.2%,表明方法准确度较好。优化高效液相色谱-原子荧光光谱法的测试参数分析形态硒,其测试结果为硒代胱氨酸、亚硒酸盐、硒代蛋氨酸、硒酸盐等4种形态硒的标准曲线在10~200μg/L浓度范围内线性关系良好,相关系数均大于0.999,检出限在2.87~4.47μg/L之间,相对标准偏差(RSD)在1.14%~2.13%之间,各形态消解前加标的加标回收率在91.6%~108.9%之间,消解后加标的加标回收率在90.1%~109.7%之间,结果表明该方法对鱼肌形态硒测定有很好的准确性和可靠性。

高效液相色谱-原子荧光光谱法应用于不同营养级鱼肌中汞的形态分析

汞是环境中最具威胁的元素之一,各形态汞的毒性不同,并且会随食物链的传递积累.因此,同时检测鱼肌中不同形态的汞含量,并分析其在不同生境及营养级的差异性具有相当重要的研究价值.通过高效液相色谱-原子荧光光谱联用法改变流动相中甲醇的浓度、光电倍增管负高压、空心阴极灯电流、还原剂及载流的浓度等条件,优化了不同汞形态组分的分离程度和响应值.在优化的试验条件下,将鱼肌样品经离心、过柱、洗脱等步骤处理后,由液相色谱分离,最终通过原子荧光法检测提取溶液中3种汞形态.结果表明,二价汞、甲基汞、乙基汞在0.2~10.0μg/L质量浓度范围内线性关系良好,相关系数均大于0.9999,方法检出限在0.39~0.82μg/kg之间,平行样品相对标准偏差(RSD)均小于4.0%.方法前处理简单,准确度高,适用于鱼肉中汞的形态分析.方法应用于不同生境、不同营养级的鱼肌样品检测,可观察到不同营养级样品结果明显的差异性及同类样品间的相关性.

正中神经鱼际肌支功能束定位显微外科解剖

目的 :为臂丛损伤后正中神经及其手内在肌支的定位提供显微外科解剖学基础。方法 :在较新鲜的上肢标本上 ,按照自然分束、醋酸浸滴法逆行显微解剖分离各功能束组 ,分段观察手内肌束组在神经干中的走行分布方位和与其他功能束的交错混合情况。结果 :(1)正中神经鱼际肌支 83 %自神经干掌桡侧汇入 ,至 5 /16平面 86%的鱼际肌支已分散到神经干截面积的 1/2以上。 (2 )正中神经鱼际肌支汇入神经干平面距尺桡骨茎突连线之间距离为 5 .3± 0 .7cm。结论 :.臂丛损伤修复正中神经手内在肌支时 ,以选择在前臂远端 (或以远 )直接修复为宜。

热诱导大豆分离蛋白对肌原纤维蛋白凝胶特性的影响

大豆分离蛋白(soybean protein isolate,SPI)经60、80和95 ℃热处理,分别与鱼肌原纤维蛋白(myofibrillar protein,MP)按质量比1∶ 3(总蛋白质量浓度45 g/L)热诱导得到混合蛋白凝胶。结果表明,从流变特性来看,与天然大豆分离蛋白复合凝胶(MP-N-SPI)相比,MP-SPI(80 ℃)的储能模量值( G ′)( P <0.05)显著上升,而MP-SPI(60 ℃和95 ℃)却低于MP-N-SPI。在MP中加入SPI后,复合凝胶的持水性均高于单纯MP,适宜的热诱导温度SPI(80 ℃),可以明显改善复合凝胶的持水力(water holding capacity,WHC)( P <0.05)。从质构特性看出, MP-SPI (95 ℃)的硬度显著提升。电泳图谱显示,MP-N-SPI凝胶条带与单纯MP无明显差异,MP-SPI(80 ℃和 95 ℃)条带比MP-N-SPI和MP-SPI(60 ℃)浅,说明预热SPI(80 ℃或95 ℃)容易与MP相互作用。化学力测定显示,预热大豆蛋白与MP的凝胶网络形成主要是疏水作用的结果,而氢键和二硫键不是复合凝胶形成的主要化学力。由此可见,适宜的热诱导大豆分离蛋白,可以明显改善复合凝胶的特性。

Research on the Lectin in Muscle Tissue of Varicorhinus macrolepis

[Objective] The paper aimed at researching lectins in muscles of Varicorhinus macrolepis and providing scientific basis for researching the adaptation mechanism and immune response of V.macrolepis to environment,which were advantageous for the protection and reproduction of V.macrolepis.[Method] V.macrolepis was used as test materials for the hemagglutination test by dialdehyde fixation to prove the existence of lectins in muscle crude homogenate of Varicorhinus macrolepis and study the physical and chemical characters.[Result] Lectins in muscle crude homogenate of V.macrolepis had shown hemagglutination effects on erythrocytes of six types of animals and had the maximum hemagglutination activity against rabbit erythrocytes,which belonged to the S-type lectins with optimal pH ranged from 4 to 8 and optimal temperature at 60 ℃.Results from the saccharide inhibition test had indicated that the sucrose was the only kind of saccharide which had inhibited the hemagglutination,suggesting that sucrose had played an important role in the process of recognition and aggregation of lectins.[Conclusion] It had been speculated that the optimal pH ranges for thermal sensitivity and hemagglutination activity of lectins in different types of aquatic organisms were similar.

Comparison of Soleus Muscle Fibers in Rats and Rabbits at Different Stages of Postnatal Development

In the present study,the effects of postnatal development on the number and distribution of skeletal muscle fibers of different types in hind leg of rat and rabbit were studied.The soleus muscles of rats aged 2 days,2,4,6,8,and 10 weeks (body weight 10,32,95,190,280,and 320 g),and rabbits aged 2 days,2,4,8,12,16,20,and 24 weeks (body weight 100,220,400,750,1 200,1 600,2 100,and 2 500 g) were stained with succinic dehydrogenase.With an image analysis system,the X-Y coordinates of fibers were used to analyze the growth-related changes.The results of present study showed that three types of fibers were found in the soleus muscles of rat and rabbit,i.e.,type Ⅰ (slow oxidative),ⅡX (fast oxidative),and ⅡA (fast oxidative glycolytic).The type Ⅰ fibers were present throughout the muscle that had a uniform distribution and tended to increase in number with aging.Type ⅡX fibers were scattered throughout the muscle and decreased markedly in number with aging.Type ⅡA fibers were located at the central and deep regions,and showed a little or no change in number and distribution with aging.While be of age,type ⅡA and ⅡX fibers became restricted to the superficial region.No type ⅡB fibers were detected.Type ⅡA fibers had the largest diameter,type Ⅰ intermediate and type ⅡX the smallest.Mean cross-sectional area of each type fibers of rabbits was larger than that of rats.The present results indicate that the number and distribution of muscle fibers of different types in hind limb of rat and rabbit change with the process of postnatal growth.

Comparative Study on Muscle Fiber Characteristics and Muscle Nutritional Quality between Two Groups of Yellow River Carps

The aim was to protect the Henan Yellow River carp germplasm resources and provide a scientific basis for the meat quality improvement of Yellow River carps. With artificially farmed and wild Henan Yellow River carps as the research objects, comparative study on muscle fiber diameter and density, routine nutritional composition, calcium and phosphorus contents and amino acids composition was conducted between the two groups of carps. The results showed that the moisture content was significantly higher （P 〈0.05）, the crude fat and crude protein contents were significantly lower （P〈0.05）, the essential amino acids and total amino acids contents were lower （P〉0.05）, the phosphorus content was higher （P 〉0.05）, and the calcium content was lower （P〉0.05） in the wild group compared with those in the farming group. The analysis of muscle fiber characteristics showed that there were significant differences in the average muscle fiber diameter （P〈0.05） and muscle fiber density （P〈0.01） between the two groups of Henan Yellow River carps.

Expansion of the Actin Gene Family in Amphioxus

Actins are a small family of ubiquitous proteins that are essential cytoskeletal components and are highly conserved during evolution. Actins are usually divided into two classes, the cytoplasmic and muscle actins, which have different functional roles. Here we systematically analyzed the actin genes in the genome of the primitive chordate amphioxus （Branchiostoma floridae）. We found that amphioxus contains more than 30 actin genes, many of which are linked. Phylogenetic analysis suggests the amphioxus actin genes have clearly undergone extensive expansion through tandem duplications. The actin genes＇ structure also varies a lot, containing 2 to 7 exons. We also cloned two muscle type of actin genes from the amphioxus （B. belcheri） and compared their expression patterns during early development. The slight difference in their expression suggests functional diversification of these actin genes. Our results shed light on the evolution both of actin genes themselves and their functional roles in chordate development.

Lipid and Fatty Acid Compositions of Cod (Gadus morhua),Haddock (Melanogrammus aeglefinus) and Halibut (Hippoglossus hippoglossus)

This study was conducted to compare lipid and fatty acid composition of cod,haddock and halibut.Three groups of cod（276 g±61 g）,haddock（538 g±83 g）and halibut（3704 g±221 g）were maintained with commercial feeds mainly based on fish meal and marine fish oil for 12 weeks prior to sampling.The fatty acid compositions of muscle and liver were determined by GC/FID after derivatization of extracted lipids into fatty acid methyl esters（FAME）.Lipids were also fractionated into neutral and polar lipids using Waters silica Sep-Pak（R）.The phospholipid fraction was further separated by high-performance thin-layer chromatography（HPTLC）and the FAME profile was obtained.Results of the present study showed that cod and haddock were lean fish and their total muscle lipid contents were 0.8% and 0.7%,respectively,with phospholipid constituting 83.6% and 87.5% of the total muscle lipid,respectively.Halibut was a medium-fat fish and its muscle lipid content was 8%,with 84% of the total muscle lipid being neutral lipid.Total liver lipid contents of cod,haddock and halibut were 36.9%,67.2% and 30.7%,respectively,of which the neutral lipids accounted for the major fraction（88.1%-97.1%）.Polyunsaturated fatty acids were the most abundant in cod and haddock muscle neutral lipid.Monounsaturated fatty acid level was the highest in halibut muscle neutral lipid.Fatty acid compositions of phospholipid were relatively constant.In summary,the liver of cod and haddock as lean fish was the main lipid reserve organ,and structural phospholipid is the major lipid form in flesh.However,as a medium-fat fish,halibut stored lipid in both their liver and muscle.

Structural Changes and Rheological Properties of Dry Abalone Meat (Haliotis diversicolor) During the Process of Water Restoration

Changes in tissue structure, rheological property and water content of dry abalone meat in the process of water restora- tion were studied. The weight and volume of dry abalone meat increased with water restoration. When observed under a light micro- scope, structural change in myofibrils was obvious and a distinct network was found. When water restoration time increased from 24 h to 72 h, the instantaneous modulus E0 and viscosity η1 increased, whereas the rupture strength and relaxation time (τ1) were re- duced. There were no significant changes of rheological parameters (E0, η1, τ1, rupture strength) from 72 h to 96 h of water restoration. Therefore, the dry abalone meat was swollen enough at the time of 72 h. The rheological parameters were obviously influenced by the structural changes.

The effects of season on fatty acid composition and ω3/ω6 ratios of northern pike(Esox lucius L.,1758) muscle lipids

In the present study, the effects of season on fatty acid composition, total lipids, and ω3/ω6 ratios of northern pike muscle lipids in Klzlhrmak River （Klrlkkale, Turkey） were investigated. A total of 35 different fatty acids were determined in gas chromatography. Among these, palmitic, oleic, and palmitoleic acids had the highest proportion. The main polyunsaturated fatty acids （PUFAs） were found to be docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid. There were more PUFAs than monounsaturated fatty acids （MUFA） in all seasons. Similarly, the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition. ω3/ω6 ratios were calculated as 1.53, 1.32, 1.97, and 1.71 in spring, summer, autumn and winter, respectively. Overall, we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.

Rheological Properties and Structural Changes in Different Sections of Boiled Abalone Meat

Changes in tissue structures, rheological properties of cross- and vertical section boiled abalone meat were studied in relation to boiling time. The adductor muscle of abalone Haliotis discus which was removed from the shell, was boiled for 1, 2, and 3 h, respectively. Then it was cut up and separated into cross- and vertical section meat. When observed by a light microscope and a scanning electron microscope, structural changes in the myofibrils were greatest in the cross section meat compared with the vertical section meat. When boiling time was increased from 1 h to 3 h, the instantaneous modulus E 0 and rupture strength of both section meat decreased gradually with increased boiling time, and no significant differences were observed between these two section meat for the same boiling time. When boiled for 1 h, the relaxation time of cross section meat was much longer than that of vertical section meat. There were no significant changes in the relaxation time of vertical section for different boiling time, but the relaxation time of cross section meat was reduced gradually with increasing boiling time. These results confirmed that the difference in rheological properties between the cross- and vertical section meat was mainly due to the denaturation level of myofibrils when heated for 1 h, as well as due to the changes in the amount of denatured proteins, and the manner in which the inner denatured protein components weve exchanged after boiling time was increased from 1 h to 3 h.

Effect of enzymatic fish frame protein hydrolysate on freeze-induced denaturation of myofibrillar protein from bighead carp fish （Aristichthys nobilis ） during frozen storage

Three kinds offish frame protein hydrolysates （PPH, APH and FPH） were prepared from fish frame of red drum （ Sciaenops ocellatus ） by papain, alkaline proteinase and flavorzyme treatment. The hydrolysates were mainly composed of peptide （83.5 % -84.6% ） and displayed different molecular weight distribution pattern. The protective effects of hydrolysates on the freeze-induced denaturation of myofibrillar protein （Mf） from bighead carp （Aristichthys nobilis） mince during storage at -20℃ for 12 weeks were investigated. The hydrolysate （5 % dried weight/wet weight） reduced the freeze-induced denaturation of Mf as evidenced by the lowered decrease in Ca-ATPase activity and reactive sulfllydryl contents as well as the impeded increase in surface hydrophobicity. Microscopic photographs indicated that the hydrolysates inhibited the growth of ice crystal in fish mince, and then prevented the aggregation of Mf during frozen storage. The protective effects of hydrolysates on freeze-induced denaturation of Mf were influenced by the molecular weight distribution. PPH had strongest cryoprotective ability among three hydrolysates.

RNA/DNA Ratio and LPL and MyoD mRNA Expressions in Muscle of Oreochromis niloticus Fed with Elevated Levels of Palm Oil

Palm oil is of great potential as one of the sustainable alternatives to fish oil(FO) in aquafeeds.In this present study,five isonitrogenous diets(32% crude protein) with elevated palm oil levels of 0%,2%,4%,6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase(LPL) and Myo D m RNA expressions in muscle of Oreochromis niloticus.The results showed that RNA,DNA content as well as ratio of RNA to DNA were significantly affected(P < 0.05),in each case the highest was recorded in fish group subjected to 6% palm oil level.There was a strong positive correlation between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and specific growth rate(SGR),protein efficiency ratio(PER),while a negative correlation existed between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and feed conversion ratio(FCR).The m RNA expressions of LPL and Myo D in muscle were not significantly affected by the different palm oil levels,although the highest expression was observed in fish fed with 6% palm oil level.There also existed a strong positive correlation between the m RNA expression of LPL,Myo D and SGR,PER,while their correlation with FCR was negative.In conclusion,elevated palm oil affected the RNA,DNA concentration as well as RNA/DNA ratio significantly,although the m RNA expression of LPL and Myo D were not affected significantly by elevated palm oil levels.

Variation in metabolic enzymatic activity in white muscle and liver of blue tilapia,Oreochromis aureus,in response to long-term thermal acclimatization

The effects of rearing temperature on white muscle and hepatic phosphofructokinase （PFK）, pyruvate kinase （PK）, lactate dehydrogenase （LDH）, aspartate aminotransferase （AST） and alanine aminotransferase （ALT） were examined in fingerlings of blue tilapia, Oreochromis aureus. The experiment was conducted for 14 weeks at temperatures of 18, 22, 26, 30, and 34℃. The activity of the glycolytic enzymes PFK, PK, and LDH in white muscle increased significantly with increase in water temperature. A reverse trend was observed for these enzymes in the liver, except for LDH, which behaved in the same manner as in white muscle. Cytosolic AST and ALT activity increased in both white muscle and liver in response to warm thermal acclimatization, while a reduction in mitochondrial AST and ALT activity was noticed at high temperatures in comparison with those at a lower temperature.

Bionic structure of shark's gill jet orifice based on artificial muscle

Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.

Concentration and Biomagnification of Heavy Metals in Biota of the Coastal Marine Areas of Tanzania

The concentrations of heavy metals （As, Hg, Cr, Pb and Zn） were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable isotopes of C and N. Macroalgae samples from the central marine areas of the Tanzanian coast had higher mean concentrations of Hg （0.17 ± 0.01 μg/g） and Cr （23.7 ± 4.15 μg/g） compared to other locations. Higher concentration of Hg （0.06 ±0.02 μg/g） was detected in the Ulva fasciata close to the Msimbazi Creek in Dares Salaam, whereas the highest concentration of Cr （45.5 ± 6.83 μg/g） was found in Ulva petrusa near Dares Salaam port. The crab Portunus pelagicus collected from Pangani river estuary contained 411.5 ± 13.04 μg/g of Zn. The other metals were uniformly distributed in macrobenthos from the entire coast. Mercury and lead in the biota were found to biomagnify along the Arius dussumieri and Lethrinus lentjan food chains as suggested by the significant positive relationships between log-pollutant concentrations in fish muscle tissues vs. 615N signatures. Zinc in muscle tissues was found to be transferred along the food webs although no biomagnification was observed. Arsenic and chromium were found to decrease with the rise of the trophic position. Metal concentrations in macroalgae, macrobenthos and fish were compared with quality guidelines values by FAO （Food and Agricultural Organization） in 1983 and they all were below permissible limits for human consumption.δ

Availability of Myoglobin as a Molecular Marker for Phylogenetic Relationships of Fish

In order to elucidate the phylogenetic relationship of fish, DNA and deduced amino acid sequences of myoglobin （Mb） were used for the phylogenetic analyses based on different approaches, namely, maximum likelihood （ML）, neighbor joining （NJ）, unweighted pair group method with arithmetic means （UPGMA） and maximum parsimony （MP） methods in comparison with the conventional molecular markers, mitochondrial cytochrome b （cyt-b） and cytochrome c oxidase subunit I （COI）. The phylogenetic trees drawn based on Mb sequences were similar to those by the traditional classification based on the other molecular markers. The primary and secondary structures, as well as the modeled tertiary structures of Mbs were similar to each other, but were clearly distinguishable among those species. Such differences in structure would be associated with adaptation of Mb molecule to the physiological conditions of each species. These results suggest that Mb can be a molecular marker for the phylogenetic relationship of fish.

Muscle Growth of Two Nile Tilapia （Oreochromis niloticus） Strains

The objective of this research was to evaluate the muscle growth of the Nile tilapias of Thai and supreme strain. Hyperplasia and hypertrophy of muscle fibers were studied by histology. The fish were cultivated in cages in a dam and as they grew they were weighed and measured in length. In tissue samples, it was evaluated the quantity of cells area~ and the diameter of the white, pink and red muscle fibers. The supreme strain presented greater number of white and pink fibers mm2 and smaller number of red fibers when compared to the Thai strain. 5-10 cm fish presented higher number of white, pink and red fibers mm： and smaller average diameter of the white and pink fibers, when compared to a 10-15 cm fish. The average diameter of the white and pink fibers increased in 10-15 cm fish, compared to 5-10 era. White fibers smaller than 10 ~tm were found only in the 5-10 cm supreme strain. Tilapias of Thai and supreme strain presented different standard distribution of red, pink and white muscle fibers. Supreme strain, genetically improved, presented higher hyperplasia of white fibers than Thai strain, and this can indicate its higher potential growth.

A natural chemical technology for reducing fluoridation through chloride contents in muscles of fish

Accumulation trend of fluoride ion was carried out in 25 fish species, collected randomly from fresh water and marine water, Sindh, Pakistan to ensure the level of chloride contents by Selective Ion Electrode （SIE） method. Results showed an inverse relation in between chloride and fluoride concentration in muscles of fish under investigation, It was observed that chloride ions contents of marine water fish were significantly higher as compared with fresh water fish. This may be related with the habitat of marine water fish while no appreciable divergence in fluoride concentration in both regions was observed. This indicated that the deliberation of fluoride is the phenomena of nature of fish and self-determining. Highest concentration of fluoride ion in fresh water fish and marine water fish showed an inverse level of chloride ion in it, reflects water body conditions of both resources. A probable mechanism of accumulation of fluoride with respect to essential chloride ion which may be related with the size of ionic radii of both halides ion is described in relevant section of this article. Where a larger ionic radii of chloride ion believed to play an imperative role in reducing fluoridation in fishes. This may be regarded as natural chemical technology for reducing fluoride in muscle （edible part） of fish of both regions.