镉浓度对烤烟幼苗镉含量及生长和生理指标的影响

为了探索重金属镉对烟草的危害机理,采用水培试验,调查了不同镉浓度处理在烟草幼苗各部位不同提取态的镉含量以及烟草幼苗干物质积累量、根系活力、叶绿素含量、硝酸还原酶活力和丙二醛含量等生理指标的变化。结果表明,烟草根系镉（Cd）以去离子水提取态为主,其次为醋酸提取态,叶片中Cd主要以醋酸结合态存在。随着镉浓度的提高,Cd存在由活性弱的化学形态向活性强的形态转化的趋势,干物质量的积累先升高后降低;不同Cd浓度处理时,烟草幼苗Cd含量表现为：茎>根>叶,随着Cd处理浓度的提高,烟草幼苗中的Cd更多的富集在烟苗的根部和茎部。根系活力和叶绿素含量逐渐降低;硝酸还原酶活性呈先升高后降低,丙二醛含量则反之。因此,与对照相比,低浓度Cd处理在一定程度上刺激烟草幼苗的某些生理活性,使其呈现更高的生物活性,但高浓度Cd处理则极显著抑制烟草幼苗的生长,使其各项生理活动降低,最终影响其正常的生长。     

功能性食品添加剂-膳食纤维

膳食纤维作为人体必不可少的“第七营养素”,因其丰富而独特的理化特性及生理功能而备受关注.文章主要论述了膳食纤维的研究现状,包括对膳食纤维的定义、分类、理化特性、生理功能、制备方法、测定方法等,为进一步研究开发其在功能食品中应用提供参考.     

基于感知视觉重要性的立体图像质量评价

视觉心理、生理因素是有效、准确评价图像质量的重要依据.尽管在计算层面已有众多视觉心理、生理计算模型及方法为其提供支持,但在图像质量评价任务中如何分析各种孤立方法之间的内在关系进而使之有效协同,是使得评价结果更符合人主观评测的关键.从图像质量评价的角度出发,功能上将人眼的视觉注意区域定义并数学形式化为视觉初期注意区域与视觉转移期的劣质区域;同时考虑人眼的感知冗余特性,结合JND感知冗余模型,进而提出了图像质量评价范畴下的视觉感知模型PVSSIM.以此为依据,将感知视觉的方法在二维图像数据库中验证其可行性,并将其引入到立体图像质量评价中.实验结果表明,提出的客观评价方法与传统方法相比,充分考虑到了图像质量评价任务中各种视觉心理、生理因素的协同,与人主观的图像质量评价相比具有更高的相关度,评价方法在立体图像库中能很好地与主观评价相吻合,达到了预期的效果.     

鲜切果蔬品质劣变影响因素及其可能机理

鲜切果蔬是指新鲜果蔬原料经预处理、清洗、切分、保鲜、包装和贮藏等多道工序制成的不影响其鲜活状态的一种制品。品质快速劣变是影响其货架寿命的主要原因。本文综述鲜切果蔬品质快速劣变的影响因素及其可能机理,旨在为鲜切果蔬贮藏保鲜新技术的建立和应用提供理论依据。     

大豆豆渣的生理功能及其在食品中的应用

豆渣是一种营养丰富的大豆制品副产物,含有膳食纤维、蛋白质、黄酮等物质。本文综述豆渣的生理功能及其在食品生产中的应用。     

无线体征监测系统的低功耗调度方法

基于超宽带(UWB)体域网和异构的生理传感器,设计了可对多种生理信息进行实时采集与处理的无线体征监测系统,并针对此类系统提出了基于体征状态机的低功耗调度方法,以便长期监测人体的健康与安全。在该调度方法中,协调器根据系统的体征状态机自适应地确定下一监测周期的传感器集合,并控制相应的生理传感器进行协同工作。仿真结果表明在同样的监测情况下,建议的调度方法有效减少了多生理传感器的不必要运行和无线传输的数据量,从而延长了整个监测系统的工作寿命。     

Decreased Interactions between Calmodulin and a Mutant Huntingtin Model Might Reduce the Cytotoxic Level of Intracellular Ca2+: A Molecular Dynamics Study

Mutant huntingtin (m-HTT) proteins and calmodulin (CaM) co-localize in the cerebral cortex with significant effects on the intracellular calcium levels by altering the specific calcium-mediated signals. Furthermore, the mutant huntingtin proteins show great affinity for CaM that can lead to a further stabilization of the mutant huntingtin aggregates. In this context, the present study focuses on describing the interactions between CaM and two huntingtin mutants from a biophysical point of view, by using classical Molecular Dynamics techniques. The huntingtin models consist of a wild-type structure, one mutant with 45 glutamine residues and the second mutant with nine additional key-point mutations from glutamine residues into proline residues (9P(EM) model). Our docking scores and binding free energy calculations show higher binding affinities of all HTT models for the C-lobe end of the CaM protein. In terms of dynamic evolution, the 9P(EM) model triggered great structural changes into the CaM protein’s structure and shows the highest fluctuation rates due to its structural transitions at the helical level from α-helices to turns and random coils. Moreover, our proposed 9P(EM) model suggests much lower interaction energies when compared to the 45Qs-HTT mutant model, this finding being in good agreement with the 9P(EM)’s antagonistic effect hypothesis on highly toxic protein–protein interactions.     

Efficient Neuroprotective Rescue of Sacsin-Related Disease Phenotypes in Zebrafish

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a multisystem hereditary ataxia associated with mutations in SACS, which encodes sacsin, a protein of still only partially understood function. Although mouse models of ARSACS mimic largely the disease progression seen in humans, their use in the validation of effective therapies has not yet been proposed. Recently, the teleost Danio rerio has attracted increasing attention as a vertebrate model that allows rapid and economical screening, of candidate molecules, and thus combines the advantages of whole-organism phenotypic assays and in vitro high-throughput screening assays. Through CRISPR/Cas9-based mutagenesis, we generated and characterized a zebrafish sacs-null mutant line that replicates the main features of ARSACS. The sacs-null fish showed motor impairment, hindbrain atrophy, mitochondrial dysfunction, and reactive oxygen species accumulation. As proof of principle for using these mutant fish in high-throughput screening studies, we showed that both acetyl-DL-leucine and tauroursodeoxycholic acid improved locomotor and biochemical phenotypes in sacs^−/− larvae treated with these neuroprotective agents, by mediating significant rescue of the molecular functions altered by sacsin loss. Taken together, the evidence here reported shows the zebrafish to be a valuable model organism for the identification of novel molecular mechanisms and for efficient and rapid in vivo optimization and screening of potential therapeutic compounds. These findings may pave the way for new interventions targeting the earliest phases of Purkinje cell degeneration in ARSACS.     

橡胶苗叶片介电参数的研究

为了能通过介电参数的检测,快速鉴别植物的生长状况。通过试验研究了橡胶苗离体叶片的生理电容和生理电阻与测量频率、测量电压的关系。试验结果表明,400Hz为较适宜的测量频率,而测量电压间无显著差异。且随着叶片离开植株时间的增加,叶片的电容值减少,电阻值增加。     

一株番茄灰霉病菌拮抗菌的系统鉴定

Y-21是从山东省淄博市蔬菜温室中分离到的一株细菌,通过室内平板对峙试验,对番茄灰霉病菌具有较强的拮抗性。本研究通过形态观察、生理生化反应和分子生物学方法对这株细菌进行系统鉴定。显微镜观察菌株形态为杆状;有芽孢;革兰氏染色呈阳性。采用经典的基因组提取方法提取基因组DNA,以其为模板,利用引物63F、1494R扩增16S rRNA基因,回收16SrRNA基因的PCR产物并与T载体连接,通过热激法将重组质粒转入大肠杆菌感受态细胞,利用蓝白斑筛选,挑出白斑,提取质粒,通过蓝白斑质粒的电泳图比对和质粒的PCR检测确定阳性克隆,将阳性克隆菌株送样测序。将测序结果输入BLAST进行比对,发现Y-21属于假单胞菌属,然后对其构建系统发育树。