骨蛋白水解物对冷藏鱼糜品质和蛋白结构特性的影响

通过测定不同贮藏时间内(0、1、3、5、7d)鲤鱼鱼糜的颜色(白度值、亮度值)、硫代巴比妥酸值、挥发盐基氮,及肌原纤维蛋白的ATPase酶活性、表面疏水性、总巯基含量等指标的变化,研究冷藏(4℃)条件下骨蛋白水解物对鲤鱼鱼糜的抗氧化效果及对蛋白的保护作用。结果表明,随着骨蛋白水解物添加量的增加,鱼糜色泽明显改善,鱼糜样品的TBRAS、TVB-N及表面疏水性呈下降趋势;而Ca2+-ATPase酶活性、总巯基含量呈上升趋势。其中添加7%骨蛋白水解物的样品效果最为明显,冷藏至第7d时,与对照组相比,样品的TVB-N及表面疏水性分别降低了1.30g/100g、1.80μg,且效果显著(p<0.05)。因此,骨蛋白水解物能够抑制淡水鱼鱼糜的蛋白和脂肪氧化变性,且浓度越高效果越明显。

不同盐对鲤鱼肌原纤维蛋白结构和凝胶特性的影响

肌原纤维蛋白是鱼肉中的主要蛋白质,对鱼糜类制品的质量起到关键的作用。文中研究了NaCl、CaCl2和Na4P2O73种盐类及其浓度对鲤鱼肌原纤维蛋白结构特性(表面疏水性、蛋白聚合程度)和凝胶特性(质构、微观结构、蛋白浊度)的影响。结果表明:鲤鱼肌原纤维蛋白的等电点为5.5;3种盐加入肌原纤维蛋白后会引起肌原纤维蛋白发生一定程度的聚集,表面疏水性降低;随着盐浓度的增大,肌原纤维蛋白凝胶硬度、弹性、浊度降低;添加CaCl2比其它盐类更明显降低鱼糜的凝胶硬度、弹性和浊度,且差异性显著(P<0.05);NaCl和Na4P2O7使鱼糜凝胶微观结构更致密、CaCl2使鱼糜凝胶微观结构变得松散。因此,在鲤鱼肌原纤维蛋白中添加NaCl、CaCl和NaPO对鱼糜肌原纤维蛋白结构和凝胶特性均有不同程度的影响。

面粉熟化过程蛋白特性变化研究

为探索面粉熟化过程(0~90 d)蛋白特性的变化,以高、中、低筋三种新磨制的小麦粉为原料,测定其各蛋白组分的变化,沉降值、谷蛋白溶胀指数的变化,以及面团微观结构的变化。结果表明:熟化过程中麦醇溶蛋白含量逐渐降低,麦谷蛋白的含量升高;沉降值及谷蛋白溶胀指数先升高、后降低,在40 d左右达到最大值;面团微观结构表明在熟化30~60 d时,面筋蛋白逐渐形成连续的网络结构,面筋的弹性增加,包裹淀粉颗粒的能力增加,气孔的数量和直径也增加。

Expression and Identification of Inclusion Forming-related Domain of NS80 Nonstructural Protein of Grass Carp Reovirus

Grass carp reovirus （GCRV）, a double stranded RNA virus that infects aquatic animals, often with disastrous effects, belongs to the genus Aquareovirus and family Reoviridea. Similar to other reoviruses, genome replication of GCRV in infected cells occurs in cytoplasmic inclusion bodies, also called viral factories. Sequences analysis revealed the nonstmctural protein NS80, encoded by GCRV segment 4, has a high similarity with μNS in MRV（Mammalian orthoreovimses）, which may be associated with viral factory formation. To understand the function of the μNS80 protein in virus replication, the initial expression and identification of the immunogenicity of the GCRV NS80 protein inclusion forming-related region （335-742） was investigated in this study. It is shown that the over-expressed fusion protein was produced by inducing with IPTG at 28℃. In addition, serum specific rabbit antibody was obtained by using super purified recombinant NS80（335-742） protein as antigen. Moreover, the expressed protein was able to bind to anti-his-tag monoclonal antibody （mouse） and NS80〈335.742） specific rabbit antibody. Further western blot analysis indicates that the antiserum could detect NS80 or NS80C protein expression in GCRV infected cells. This data provides a foundation for further investigation of the role of NS80 in viral inclusion formation and virion assembly.

Molecular Characterization of Nonstructural Protein NS38 of Grass Carp Reovirus

Viral nonstructural proteins in both enveloped and non-enveloped viruses play important roles in viral replication. Protein NS38 of Grass carp reovirus (GCRV), has been deduced to be a non-structural protein, and, consistent with other reoviruses, is considered to cooperate with the NS80 protein in viral particle assembly. To investigate the molecular basis of the role of NS38, a complete protein was expressed in E.coli for the first time. It was found that there is a better expression of NS38 induced with IPTG at 28 ℃ rather than 37 ℃. In addition, the antiserum of NS38 prepared with purified fusion protein and injected into rabbit could be used for detecting NS38 protein expression in GCRV infected cell lysate, while there is not any reaction crossed with purified virus particle, confirming NS38 is not a component of the viral structural protein. The result reported in this study will provide evidence for further viral protein-protein and protein-RNA interaction in dsRNA viruses replication.

一种混合深度神经网络的赖氨酸乙酰化位点预测方法

赖氨酸乙酰化(Lysine acetylation,Kace)普遍存在于人体代谢酶中,与多种代谢疾病密切相关,因此准确识别该位点对于代谢疾病治疗的研究具有重要意义.现有的Kace位点预测方法大多采用蛋白质序列层面的信息作为输入,蛋白质结构特性考虑不全面;特征提取时未关注氨基酸残基间顺序相关性,信息丢失严重,降低了预测准确度.提出一种新的Kace位点预测深度学习CL-Kace模型.CL-Kace引入蛋白质结构特性,并与蛋白质原始序列、氨基酸理化属性共同构建位点特征空间,采用卷积神经网络(Convolutional Neural Network,CNN)提取特征;引入双向长短期记忆(Bidirectional Long Short-Term Memory,BiLSTM)网络捕获残基间的顺序依赖关系,以提高网络的抽象能力,识别潜在的Kace位点.实验结果表明,CL-Kace模型优于现有的Kace位点预测器,能够有效地预测潜在的位点.

Molecular Dissection of Bombyx mori Nucleopolyhedrovirus orf8 Gene

Viruses including baculoviruses are obligatory parasites, as their genomes do not encode all the proteins required for replication. Therefore, viruses have evolved to exploit the behavior and the physiology of their hosts and olden coevolved with their hosts over millions of years. Recent comparative analyses of complete genome sequences of baculoviruses revealed the patterns of gene acquisitions and losses that have occurred during baculovirus evolution. In addition, knowledge of virus genes has also provided understanding of the mechanism of baculovirus infection including replication, species-specific virulence and host range. The Bm8 gene of Bombyx mori nucleopolyhedrovirus （NPV） and its homologues are found only in group I NPV genomes. The Autographa californica NPV Ac 16 gene is a homologue of Bm8 and, encodes a viral structural protein. It has been shown that BmS/Ac 16 interacts with baculoviral and cellular proteins. BmS/Ac 16 interacts with baculoviral IE1 that is facilitated by coiled coil domains, and the interaction with IE1 is important for Bin8 function. Acl6 also forms a complex with viral FP25 and cellular actin and associates with membranes via palmitoylation. These data suggested that this gene family encodes a multifunctional protein that accomplishes specific needs of group I NPVs.

Characterization of a recombinant Akabane mutant virus with knockout of a nonstructural protein NSs in a pregnant goat model

Dear Editor,Akabane virus(AKAV),an orthobunyavirus,is transmitted primarily by biting midges and is widely distributed throughout the world except the Europe.AKAV was first isolated from mosquitoes in Japan(Oya et al.,1961).Although pregnant cows,ewes,and goats infected with AKAV exhibit no clinical signs of disease,in utero infections result in abortion,premature birth,stillbirth。