A colloidal silver staining--destaining method for precise assignment of immunoreactive spots in two-dimensional protein patterns

The characterization of protein expression patterns by two-dimensional gel electrophoresis depends on efficient and reliable identification strategies for target spots. In addition to sophisticated techniques, such as microsequencing and peptide mass spectrometry, immunodetection of membrane-immobilized proteins is a valuable method with which to identify the corresponding spots for a given set of candidate proteins. To precisely assign immunoreactive spots, this approach requires specific immunodetection and staining of total protein to be performed on the same membrane. Here, we describe a highly sensitive, colloidal silver-based method for the assignment of immunoreactive spots in two-dimensional protein patterns. This simple and rapid procedure involves a destaining step after staining of nitrocellulose-bound proteins with colloidal silver. We show that destaining of proteins is a prerequisite for subsequent immunodetection using enhanced chemiluminescence. Several types of antibodies were successfully employed for antigen detection after the staining-destaining procedure. Our results demonstrate that the colloidal silver-based method is generally applicable for the unambiguous identification of candidate proteins in complex two-dimensional patterns.     

Entrainment, Instability, Quasi-periodicity, and Chaos in a Compound Neural Oscillator

We studied the dynamical behavior of a class of compound central pattern generator (CPG) models consisting of a simple neural network oscillator driven by both constant and periodic inputs of varying amplitudes, frequencies, and phases. We focused on a specific oscillator composed of two mutually inhibiting types of neuron (inspiratory and expiratory neurons) that may be considered as a minimal model of the mammalian respiratory rhythm generator. The simulation results demonstrated how a simple CPG model— with a minimum number of neurons and mild nonlinearities— may reproduce a host of complex dynamical behaviors under various periodic inputs. In particular, the network oscillated spontaneously only when both neurons received adequate and proportionate constant excitations. In the presence of a periodic source, the spontaneous rhythm was overriden by an entrained oscillation of varying forms depending on the nature of the source. Stable entrained oscillations were inducible by two types of inputs: (1) anti-phase periodic inputs with alternating agonist-antagonist drives to both neurons and (2) a single periodic drive to only one of the neurons. In-phase inputs, which exert periodic drives of similar magnitude and phase relationships to both neurons, resulted in varying disruptions of the entrained oscillations including magnitude attenuation, harmonic and phase distortions, and quasi-periodic interference. In the absence of significant phasic feedback, chaotic motion developed only when the CPG was driven by multiple periodic inputs. Apneic episodes with repetitive alternation of active (intrinsic oscillation) and inactive (cessation of oscillation) states developed when the network was driven by a moderate periodic input of low frequency. %and amplitudes of intermediate strength, Similar results were demonstrated in other, more complex oscillator models (that is, half-center oscillator and three-phase respiratory network model). These theoretical results may have important implications in elucidating the mechanisms of rhythmogenesis in the mature and developing respiratory CPG as well as other compound CPGs in mammalian and invertebrate nervous systems.     

具有两个状态脉冲控制的害虫治理模型的阶一周期解的存在性和吸引性

在文献[10]的基础上,基于害虫治理问题,建立具有两个状态脉冲控制的HollingⅡ功能性反应的害虫治理模型,利用所定义的后继函数和分析的方法研究了系统阶一周期解的存在性和吸引性.     

Identification of glycoproteins on nitrocellulose membranes and gels

In this article we describe a procedure for the detection of glycoproteins on gels employing the periodic acid-Schiff’s reagent. In addition, a number of staining protocols and direct binding ELISA, employing antibodies and lectins, are described for the identification and quantitation of glycoproteins after their immobilization by dot, slot, or Western blotting onto nitrocellulose membranes. We document, in detail, the conditions (i.e., the effect of solvent and detergents) for the immobilization of one specific family of O-linked glycoproteins, namely mucins. However, taking into account our suggestions, these procedures should be applicable to other types of glycoprotein.     

雌核发育银鲫和两性融合彩鲫卵母细胞体外诱导成熟过程中周期蛋白合成和MPF活性变化的比较研究

采用体外诱导卵母细胞成熟技术 ,比较研究了雌核发育银鲫和两性融合发育彩鲫卵母细胞成熟过程中周期蛋白合成和MPF活性变化情况。结果表明 :1 7α ,2 0 β 二氢孕酮(简称DP)浓度为 0 5μg/ml,温度为 2 4℃ ,光照时间 2 0小时为最适诱导条件。在相同条件下 ,两性生殖彩鲫卵母细胞体外诱导成熟速度明显快于银鲫。相应的细胞学研究表明 ,在体外诱导时 ,银鲫和彩鲫卵母细胞的发育成熟是正常的。银鲫卵母细胞生发泡破裂 (GVBD)时已有周期蛋白的合成 ,但生发泡破裂开始后则呈现合成速度下降直至没有合成的现象。尽管如此 ,卵母细胞中MPF活性却仍保持继续增强之势 ,至GVBD达1 0 0 %时 ,活性最强。而在两性融合发育彩鲫卵母细胞成熟过程中 ,周期蛋白的合成呈现出由较多到无 ,再逐渐到多的变化。GVBD开始时 ,周期蛋白合成较多 ,此后则急剧下降至几无周期蛋白的合成 ,以后随着成熟诱导的进行 ,周期蛋白的合成速度又缓慢回升至GVBD开始时的状态。与此相对应 ,MPF活性也出现从较强变无 ,再逐渐增至最强的变迁。这些结果初步揭示 ,鱼类卵母细胞中周期蛋白的合成和MPF活性的出现与卵母细胞的成熟分裂密切相关 ,雌核发育银鲫卵母细胞生发泡破裂开始以后 ,周期蛋白合成的消失可能与其特殊的三极纺锤体形成及其后的动力     

二元神经网络模型概周期解的存在性

本文研究了两个神经元的神经网络模型y1(t)=-α1y1(t) f(y2(t-T1) -Г2)) J1(t),y2(t)=-α2y2(t) g(y1(t-T2)-Г1)) J2(t)概周期解的存在性,获得存在概周期解的充分条件。     

Crystallization of silver through reduction process using Elaeis guineensis biosolid extract

This study presents a special, economically valuable, unprecedented eco-friendly green process for the synthesis of silver nanoparticles. The silver nanoparticles were obtained from a waste material with oil palm biosolid extract as the reducing agent. The use of the oil palm biosolid extract for the nanoparticle synthesis offers the benefit of amenability for large-scale production. An aqueous solution of silver (Ag(+) ) ions was treated with the oil palm biosolid extract for the formation of Ag nanoparticles. The nanometallic dispersion was characterized by surface plasmon absorbance measuring 428 nm. Transmission electron microscopy showed the formation of silver nanoparticles in the range of 5-50 nm. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction analysis of the freeze-dried powder confirmed the formation of metallic silver nanoparticles. Moreover, Fourier Transform Infrared Spectroscopy provided evidence of phenolics or proteins as the biomolecules that were likely responsible for the reduction and capping agent, which helps to increase the stability of the synthesized silver nanoparticles. In addition, we have optimized the production with various parameters.     

Chromosomal organization of ribosomal genes and NOR-associated heterochromatin, and NOR activity in some populations of Allium commutatum Guss. (Alliaceae)

The position and the number of 18S-5.8S-26S and 5S rDNA loci, characterization of nucleolar organizing region (NOR)-associated heterochromatin and NOR activity assessment are given for six south-eastern Adriatic populations of Allium commutatum Guss. The karyotype characteristics were identical for all the populations studied, even those of distant islands. Diploid karyotypes (2 n = 16) always possessed two NOR-bearing chromosome pairs with pericentric and median secondary constrictions (SCs) on the short arm of the chromosomes VII and VIII. Fluorescent in situ hybridization (FISH) confirmed that these were the only sites of 18S-5.8S-26S rRNA genes. NOR-associated heterochromatin was of the constitutive character as shown after C-banding. Differential fluorochrome banding with Chromomycin A3 (CMA) and 4,6-diamidino-2-phenylindole (DAPI) revealed that this heterochromatin comprises both GC- and AT-rich DNA segments. Heteromorphism of C- and CMA-bands was noticed between homologous NOR-bearing chromosomes. The maximum number of four active NORs was correlated with the maximum number of four nucleoli in interphase. Variability of NOR-activity, expressed as number and size of silver stained NORs, existed between cells and between individuals of the same population. The different size of homologous and nonhomologous silver stained NORs was correlated with the extension of SCs. The only 5S rDNA locus was in an intercalary position on short arm of the chromosome VI, at the region of AT-rich constitutive heterochromatin. Dimorphism of C-bands and DAPI/Hoechst(H)-fluorescent bands was noticed between homologous chromosomes VI. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 99–108.     

Characteristics of structural proteins of infectious flacherie virus from the silkworm, Bombyx mori

Structural proteins and the characteristics of infectious flacherie virus (IFV) purified from the silkworm, Bombyx mori, are described. The purified IFV had four major structural proteins, which were detected only in high concentration gels of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and a few minor ones. Molecular weights of the major proteins were 35,200 (VP 1), 33,000 (VP 2), 31,200 (VP 3), and 11,600 (VP 4), and numbers per virion were 62, 57, 54, and 31, respectively. Amino acid compositions of VP 1, VP 2, and VP 3 were similar to each other but that of VP 4 was somewhat different. By isoelectric focusing and two-dimensional electrophoresis, high resolution of the structural proteins was obtained with silver staining. The isoelectric points of the four major proteins were determined as 7.7(VP 1), 6.7(VP 2), 4.8(VP 3), and 5.5(VP 4). This work is the first report on insect picornaviruses that presents some discriminative properties of each viral protein that was compared to those of mammalian picornaviruses.