Gel Strengthening Effect of Wood Extract on Surimi Produced from Mackerel Stored in Ice

ABSTRACT:  The effect of ethanolic kiam wood extract (EKWE) and commercial tannin (CT) on the gel properties of surimi produced from mackerel ( Rastrelliger kanagurta ) stored in ice for different times (0 to 12 d) was studied. During 12 d of iced storage, pH, total volatile base (TVB), trimethylamine (TMA), and trichloroacetic acid (TCA)-soluble peptide contents as well as thiobarbituric acid-reactive substances (TBARS) of mackerel mince increased while myosin heavy chain (MHC) band intensity decreased continuously ( P  < 0.05). The result suggested that deterioration, protein degradation, and lipid oxidation proceeded with increasing storage time. For corresponding surimi, TVB and TMA were almost removed and TBARS and TCA soluble peptide contents were decreased. Conversely, MHC became more concentrated. Decreases in gel-forming ability of surimi were observed when fish used as raw material were stored in ice for a longer time, regardless of EKWE or CT addition. Whiteness of surimi gel decreased and expressible moisture increased especially when the storage time increased. However, superior breaking force and deformation of surimi gel with 0.15% EKWE or 0.30% CT added, compared to those of the control gel were observed during the first 6 d of the storage. Thereafter, EKWE and CT had no gel enhancing effect on surimi. Therefore, freshness was a crucial factor determining gel enhancing ability of EKWE or CT toward mackerel surimi.     

Nitro-Oleic Acid (NO2-OA) Improves Systolic Function in Dilated Cardiomyopathy by Attenuating Myocardial Fibrosis

Nitro-oleic acid (NO₂-OA), a nitric oxide (NO)- and nitrite (NO₂⁻)-derived electrophilic fatty acid metabolite, displays anti-inflammatory and anti-fibrotic signaling actions and therapeutic benefit in murine models of ischemia-reperfusion, atrial fibrillation, and pulmonary hypertension. Muscle LIM protein-deficient mice (Mlp^−/−) develop dilated cardiomyopathy (DCM), characterized by impaired left ventricular function and increased ventricular fibrosis at the age of 8 weeks. This study investigated the effects of NO₂-OA on cardiac function in Mlp^−/− mice both in vivo and in vitro. Mlp^−/− mice were treated with NO₂-OA or vehicle for 4 weeks via subcutaneous osmotic minipumps. Wildtype (WT) littermates treated with vehicle served as controls. Mlp^−/− mice exhibited enhanced TGFβ signalling, fibrosis and severely reduced left ventricular systolic function. NO₂-OA treatment attenuated interstitial myocardial fibrosis and substantially improved left ventricular systolic function in Mlp^−/− mice. In vitro studies of TGFβ-stimulated primary cardiac fibroblasts further revealed that the anti-fibrotic effects of NO₂-OA rely on its capability to attenuate fibroblast to myofibroblast transdifferentiation by inhibiting phosphorylation of TGFβ downstream targets. In conclusion, we demonstrate a substantial therapeutic benefit of NO₂-OA in a murine model of DCM, mediated by interfering with endogenously activated TGFβ signaling.     

动态驾驶环境所致人体肌肉疲劳的生物信号实验研究

为了评价不同的振动驾驶环境对人体舒适性的影响,通过模拟动态驾驶环境实验,采集了人体在不同振动强度下的表面肌电信号(SEMG).对其进行时域分析求得了积分肌电值(IEMG),应用频域分析对其进行特征值提取,得到了局部肌电幅度的中值频率(MF)与振动加速度、振动时间的关系,以及人体肱二头肌、竖脊肌、股二头肌的局部肌电与振动参数间的关系.实验中,借助近红外光谱技术(NIRS)观测与分析了肱二头肌、股二头肌和竖脊肌在不同振动环境下的肌氧含量变化特点,同时监测了脑氧含量的变化趋势,并对各振动环境下的人体舒适性及疲劳进行了主观评价实验.实验研究表明,振动驾驶环境直接影响人体的肌肉疲劳过程和人体的肌氧含量、脑氧含量,不同的振动环境会对人体肌肉疲劳及舒适性产生不同的影响.研究结果可为动态环境机械系统的人 车界面设计及操作舒适度的评定提供客观、有效的技术参考.     

运动对肉鸡肉品质及肌纤维发育的影响

旨在分析运动对鸡肉品质和肌纤维发育的影响,选用36 只3 周龄爱拔益加（Arbor Acres,AA）肉鸡,按体质量相近分为对照组和运动组,实验从第4周开始训练到第9周后结束,为期6 周。在5、7、9 周龄时对肉鸡白天运动量、肌肉品质和肌纤维特性指标进行测定。结果表明：持续训练运动组,每周肉鸡白天活动量均显著高于对照组（P＜0.05）,中午休憩,运动组节律清晰。在9 周龄,运动组胸肌肉色L*值和a*值、腿肌肉色a*值、肌纤维直径显著高于对照组（P＜0.05）,运动组腿肌肌纤维密度显著低于对照组（P＜0.05）。结论：强制运动可增加肉鸡白天活动量,在持续6 周后显现改善肉色,促进肉鸡腿肌肌纤维发育的效果。     

白鲢鱼背侧肌焦磷酸酶的纯化及酶学特性

通过粗分离、50%～80%饱和度硫酸铵分级沉降、DE-52阴离子交换柱层析等步骤,从白鲢鱼背侧肌中分离纯化出焦磷酸酶。通过变性凝胶电泳分析,该酶在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳图谱中仅有一个分子质量为40 kD的条带。酶学特性研究表明,白鲢鱼背侧肌焦磷酸酶可专一性地水解焦磷酸盐,反应初速率时间范围为0～15 min,最适反应温度为45 ℃,最适反应pH值为7.5。Mg2＋对该酶有明显的激活作用,在Mg2＋浓度为5 mmol/L时酶活力最高。5 mmol/L的Ca2＋、Zn2＋、乙二胺四乙酸（ethylenediaminetetraacetic acid,EDTA）-Na2、EDTA-Na4、KIO3和1 mmol/L的NaF均对该酶有强烈的抑制作用。该酶水解焦磷酸四钠的最大反应速率为0.051 U/mg,米氏常数为0.54 mmol/L。     

微冻保鲜方法对带鱼品质及组织结构的影响

以舟山东海带鱼为原料,分别于冷藏（4 ℃）、微冻贮藏（－3 ℃）和冻藏（－18 ℃）3 种低温条件下,研究贮藏30 d内带鱼的pH值、电导率、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、硫代巴比妥酸（thiobarbituric acid,TBA）、盐溶性蛋白含量、Ca2＋-ATPase活性等理化指标变化,结合带鱼感官评价,比较微冻保鲜方法与其他2 种不同低温保鲜方式对带鱼品质的影响,并观察其肌肉微观组织结构变化。结果表明：随着贮藏时间的延长,3 种低温保鲜方式下带鱼的pH值呈现先下降后上升的趋势;电导率、TBA值、TVB-N值都随贮藏时间的延长而逐渐升高;盐溶性蛋白含量、Ca2＋-ATPase活性和感官评分都随着贮藏时间的延长呈现下降趋势,其中冻藏方式下带鱼品质保持较好,其次为微冻保鲜,冷藏条件下带鱼品质下降最快。观察其肌肉微观组织发现,短期贮藏以微冻组样品细胞完整性最好,而长期贮藏时冻藏方法维持其结构完整效果最好。     

木薯淀粉对猪肉盐溶蛋白凝胶特性的影响

研究了添加木薯淀粉对猪肉盐溶蛋白凝胶功能特性的影响。用质构仪、流变仪和离心法测定了凝胶质构、动态流变和保水性的变化,用低场核磁共振仪和扫描电镜分析了凝胶的水分状态和微观结构变化。结果表明,添加木薯淀粉不仅改善了猪肉盐溶蛋白凝胶的质构和保水性能,还改变了凝胶成型温度,单独盐溶蛋白凝胶储能模量在72℃时已达到最大值,添加木薯淀粉凝胶储能模量在80℃达到最大值;当木薯淀粉添加量为1.5%时,凝胶的硬度、弹性和保水性均达到最大,分别为379.02 g、0.85和85.16%,低场核磁共振分析表明添加1.5%木薯淀粉提高了凝胶的结合水和不易流动比例,从而提高了凝胶的保水性能,扫描电镜观察发现此时木薯淀粉主要通过填充效应贯穿在盐溶蛋白分子空隙之间,使凝胶更加紧密和有序。     

From Bipotent Neuromesodermal Progenitors to Neural-Mesodermal Interactions during Embryonic Development

To ensure the formation of a properly patterned embryo, multiple processes must operate harmoniously at sequential phases of development. This is implemented by mutual interactions between cells and tissues that together regulate the segregation and specification of cells, their growth and morphogenesis. The formation of the spinal cord and paraxial mesoderm derivatives exquisitely illustrate these processes. Following early gastrulation, while the vertebrate body elongates, a population of bipotent neuromesodermal progenitors resident in the posterior region of the embryo generate both neural and mesodermal lineages. At later stages, the somitic mesoderm regulates aspects of neural patterning and differentiation of both central and peripheral neural progenitors. Reciprocally, neural precursors influence the paraxial mesoderm to regulate somite-derived myogenesis and additional processes by distinct mechanisms. Central to this crosstalk is the activity of the axial notochord, which, via sonic hedgehog signaling, plays pivotal roles in neural, skeletal muscle and cartilage ontogeny. Here, we discuss the cellular and molecular basis underlying this complex developmental plan, with a focus on the logic of sonic hedgehog activities in the coordination of the neural-mesodermal axis.     

不同饲养方式的部位肉制作的哈萨克风干牛肉挥发性风味成分差异分析

采用电子鼻和固相微萃取-气相色谱-质谱联用法分析了2种不同饲养方式、3个不同肌肉部位样品的挥发性风味成分。电子鼻分析结果表明,2种不同饲养方式的样品之间风味差异较大,相同饲养方式、不同肌肉部位的样品之间风味差异较小。固相微萃取-气相色谱-质谱法共检测出26种挥发性风味物质,包括醛类8种、醇类7种、含苯芳香化合物6种、脂肪烃3种、酮类1种、呋喃1种。方差分析结果表明,肌肉类型对来自脂肪氧化产物总量有显著影响(P0.05),而饲养方式对来自饲料成分总量有极显著影响(P0.01)。     

Myogenic Potential of Extracellular Matrix Derived from Decellularized Bovine Pericardium

Skeletal muscles represent 40% of body mass and its native regenerative capacity can be permanently lost after a traumatic injury, congenital diseases, or tumor ablation. The absence of physiological regeneration can hinder muscle repair preventing normal muscle tissue functions. To date, tissue engineering (TE) represents one promising option for treating muscle injuries and wasting. In particular, hydrogels derived from the decellularized extracellular matrix (dECM) are widely investigated in tissue engineering applications thanks to their essential role in guiding muscle regeneration. In this work, the myogenic potential of dECM substrate, obtained from decellularized bovine pericardium (Tissuegraft Srl), was evaluated in vitro using C2C12 murine muscle cells. To assess myotubes formation, the width, length, and fusion indexes were measured during the differentiation time course. Additionally, the ability of dECM to support myogenesis was assessed by measuring the expression of specific myogenic markers: α-smooth muscle actin (α-sma), myogenin, and myosin heavy chain (MHC). The results obtained suggest that the dECM niche was able to support and enhance the myogenic potential of C2C12 cells in comparison of those grown on a plastic standard surface. Thus, the use of extracellular matrix proteins, as biomaterial supports, could represent a promising therapeutic strategy for skeletal muscle tissue engineering.