等电点沉淀法分离大豆球蛋白酸性亚基和碱性亚基

利用β-巯基乙醇切断大豆球蛋白酸性亚基和碱性亚基之间二硫键的基础上,根据两类亚基等电点的差异分离纯化大豆球蛋白亚基,从而建立了分离大豆球蛋白酸性亚基和碱性亚基的等电点沉淀法。利用这一方法分离得到的酸性亚基和碱性亚基纯度分别为92.69%和80.76%,酸性亚基和碱性亚基的净产率分别达31.40%和41.64%。该方法是一种简单有效、价格低廉的大豆球蛋白亚基分离方法。

Characterization of the Full-length cDNA, Chromosomal Localization, and Polymorphism of the Porcine RPLP0 Gene

RPLPO gene encodes the acidic ribosomal phosphoprotein large P0 subunit, which is a component of the 60S subunit. The full-length cDNA sequence of porcine RPLPO was obtained from skeletal muscle of fetal pig cDNA library and deposited in GenBank. The nucleotide sequence and the predicted protein sequence shared high sequence identity with other mammalian homologues. A C/A single nucleotide substitution in exon 5 was detected as Csp6 Ⅰ polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） shows allele frequency diversity among Tongcheng, Xiaomeishan, Yushan, Large White, Landrace, and Duroc breeds. Analyses of somatic cell hybrid panel （SCI-IP） and radiation hybrid （IMpRH） panel showed that the RPLPO gene was mapped to SSC 14q22-q24 and was closely linked to locus SW1321 （25 cR, LOD = 14.54）.

Evaluation of eikonic characteristic of skeletal metastasis of primary pulmonary carcinoma with ^(99)Tc^m methylene diphosphonate whole-body bone scans

Objective： The aim of our study was to explore the eikonic characteristic of skeletal metastasis of primary pul- monary carcinoma. Methods： Whole-body bone scans with 99Tcm methylene diphosphonate were performed in 258 patients with pathologically proven pulmonary carcinoma. The rate of skeletal metastasis, distribution of the metastatic lesions and their characteristics were analyzed. Results： Among the total 258 patients, 142 cases developed skeletal metastasis. The overall rate of skeletal metastasis was 55.0%. The metastases located in axial skeleton were 49.6%, appendicular skeleton 36.0%, trunk bones of the axial skeleton 48.4%, and appendicular girdle skeleton 31.4%. Ribs, thoracic vertebrae, ilium and lumbar vertebrae had a higher rate of skeletal metastasis, which were 38.4%, 24.0%, 21.7%, 20.2%, respectively. 1252 le- sions were detected including 406 at the left side of the body, 387 lesions at the middle position and 459 at the right side of the body. There was no significant difference in terms of number of lesions between left side and right side （X2 = 3.3, P = 0.072）. 1224 skeletal metastatic foci （97.8%） were presented as strong radioactive, 26 （2.1%） as mixed lesions, and 2 （0.2%） as low radioactive. According to the shape of lesions, there were 810 punctate lesions （71.5%）, 159 （14.0%） lump form, 108 （9.5%） strip form and 56 （4.9%） lamellar form. The accumulative skeletal metastasis rate was 28.7% for the patients with one to three lesions. The metastasis rate decreased gradually as the number of metastatic lesions increased. Conclusion： Skeletal metastasis is very common in patients with pulmonary carcinoma. Most skeletal metastases are characterized by strong radio- active and earlier punctate form; they often occur in the trunk bones of axial skeleton or appendicular girdles. The distribution of earlier metastases has not obvious regularity, and advanced skeletal metastases are widely and randomly distributed in the body, which are characterized by often concurrently multiple and polymorphous lesions.

Effect of surfactant on zeta potential and rheology behavior of methylene bis (thiocyanate) suspension concentrate

Methylene bis(thiocyanate)(MBT) is insoluble in water, so suspension concentrate(SC) of MBT is extremely relied on surfactants. In this paper, SC of MBT was prepared with wet-grinding technology, and the effect of surfactants,such as Morwet D425(D425) and Morwet EFW(EFW)(two kinds of dispersant), on the Zeta potential and rheology behavior of MBT SC were investigated. The results showed that the Zeta potential absolute value of MBT SC increased with the increasing content of D425, and it decreased with the increasing content of EFW at acidic solution(pH = 4.5). In the combination system of D425 and EFW, Zeta potential of MBT SC decreased first and then increased with the increasing content of EFW. The relationship between shear rate(γ) and viscosity(η) was studied according to Herschel–Bulkley model: η = η0+ k/γ, and the relationship between shear rate(γ) and shear force(τ) was investigated according to:τ = τ0+Kγ~n. It was revealed that the mixed fluid belonged to Yield Pseudoplastic Fluid.

大豆球蛋白的纤维聚集体行为及其稳定性研究

为了明确蛋白质的纤维聚集行为,本研究以大豆球蛋白(soy globulin,11S)为原料,从亚基层面对酸性条件下热诱导的11S纤维聚集过程进行跟踪,监测蛋白及其亚基的水解过程、结构变化及其稳定性。结果表明,11S的纤维化是一个多步骤的过程,包括多肽链的水解、自组装成淀粉样纤维聚集结构及逐渐生长成宏观可见的具有扭曲螺旋结构的纤维聚集体。与11S纤维化过程的单指数增长相比,酸性亚基的纤维化过程存在迟滞期。酸性亚基在纤维化聚集的初期主要贡献于纤维聚集的成核过程,碱性亚基的加入改变其纤维聚集进程。蛋白质的纤维化过程会增加11S在等电点处的溶解度,降低中性和酸性pH下的溶解度。此外,碱性环境(pH值10.0)会导致11S纤维聚集体全部溶解、宏观纤维长度变小、结构发生改变。以上研究结果旨在为合理利用蛋白纤维化聚集体作为新的功能性食品配料提供理论依据。

Three-dimensional supramolecular architecture based on 4,4'-methylene-bis(benzenamine) and aromatic carboxylic acid guests:Synthons cooperation,robust motifs and structural diversity

The two-component solid forms involving 4,4'-methylene-bis(benzenamine) included both salts and co-crystals,while 4,4'methylene-bis(benzenamine) crystallized exclusively as a salt,in agreement with the differences in the pK a values.Many of the crystal structures displayed either the neutral or the ionic form of the carboxylic acid-amino heterosynthon,and the similarity in crystal structures between the neutral and the ionized molecules makes the visual distinction between a salt and co-crystal dependent on the experimental location of the acidic proton.A variety of supramolecular hydrogen bonded motifs involving interactions between the aza molecules and carboxylic acid groups are observed rather than just the O-H···N/O-H···O motif.The motifs are identical in all the two compounds analyzed showing the robustness of these supramolecular synthons.In all adducts,recognition between the constituents is established through either N-H···O and/or O-H···O/O-H···N pairwise hydrogen bonds.In all adducts,COOH functional groups available on 1 and 2 interact with the N-donor compounds.The COOH moieties in 1 forms only single N-H···O hydrogen bonds,whereas in 2,it forms pairwise O-H···N/N-H···O hydrogen bonds.The supramolecular architectures are elegant and simple,with stacking of networks in 2,but a rather complex network with a threefold interpenetration pattern was found in 1.Thermal stability of these compounds has been investigated by thermogravimetric analysis(TGA) of mass loss.

Lubricating properties of polyalkylene glycol and organic phosphate ester mixed aqueous solutions

Till now,water based lubricants,especially aqueous solutions,have not been employed in the elastohydrodynamic lubrication(EHL)due to their poor film forming capability or low wear resistance.In this paper,we proposed a method to develop water based lubricant:employing polyalkylene glycol solution as base stock to improve EHL film forming capability and using organic phosphate ester(DPZ)as anti-wear additive to improve wear resistance property.The lubricating properties of the mixed solutions,including load carrying capability,wear resistance property,friction reduction property,EHL film forming behavior,were investigated.The experimental results indicate that the mixed solution presents excellent lubricating properties,which make it a promising candidate in developing water based lubricants.