Effects of Various Viscosity Enhancers and pH on Separating Haem from Porcine Red Blood Cells

Haem derived from animal blood is a valuable source of organic iron which may be used as a supplement in foods. The purpose of this study was to examine the effects of sodium carboxymethyl cellulose (NaCMC), propylene glycol alginate (PGA) and sodium alginate (SA) as viscosity enhancers on the separation of haem from porcine red blood cells, and on the distribution of iron between the haem and non-haem fractions of the extracts. Iron determinations were carried out spectrophotometrically on the supernatants obtained by centrifuging the cell suspensions and on two successive washings of the cells. In the first washings the total extracted iron content using NaCMC was highest when a high-viscosity grade was used; there were no significant differences (P>0·05) between the results obtained with this material and those obtained using PGA or SA. There were also no significant differences (P>0·05) among the three treatments in terms of non-haem content. The absorbances at 540nm of the first washings were lower when the washing was carried out at pH 1·4 rather than at pH 1·0 or 2·0. There were no significant differences associated with changes in the viscosity enhancer in the absorbances of the second washings, but the absorbances at pH 1·4 were generally higher than those at pH 1·0 or 2·0. Enhancement of the absorbances on the addition of 1,10-o-phenanthroline indicated that the extracted iron was present in the ferrous form.     

乙酰柠檬酸三丁酯的催化合成

目前常用的邻苯二甲酸酯类增塑剂可能诱发致癌,国内外都在寻找能够替代的无毒增塑剂,柠檬酸酯类增塑剂是安全的替代增塑剂之一.今以柠檬酸三丁酯和乙酸酐为原料,研究了硫酸氢钠、大孔强酸性阳离子交换树脂催化合成乙酰柠檬酸三丁酯的过程,考察了原料摩尔配比、催化剂用量、反应时间、反应温度对乙酰柠檬酸三丁酯收率的影响.在适宜条件下,两种催化剂催化合成乙酰柠檬酸三丁酯的收率可分别达到99.5%和99.8%.精制后,乙酰柠檬酸三丁酯的含量经气相色谱分析大于99%.催化剂重复使用情况的考察表明:硫酸氢钠有较好的重复使用性;使用后经无水乙醇洗涤并干燥过的大孔强酸性阳离子交换树脂也具有很好的重复使用性.     

Effect of Ions and Sequence Variants on the Antagonist Binding Properties of the Histamine H1 Receptor

The histamine H₁ receptor (H₁R) is a G protein-coupled receptor (GPCR) and represents a main target in the treatment of allergic reactions as well as inflammatory reactions and depressions. Although the overall effect of antagonists on H₁ function has been extensively investigated, rather little is known about the potential modulatory effect of ions or sequence variants on antagonist binding. We investigated the dynamics of a phosphate ion present in the crystal structure and of a sodium ion, for which we determined the position in the allosteric pocket by metadynamics simulations. Both types of ions exhibit significant dynamics within their binding site; however, some key contacts remain stable over the simulation time, which might be exploited to develop more potent drugs targeting these sites. The dynamics of the ions is almost unaffected by the presence or absence of doxepin, as also reflected in their small effect (less than 1 kcal·mol⁻¹) on doxepin binding affinity. We also examined the effect of four H₁R sequence variants observed in the human population on doxepin binding. These variants cause a reduction in doxepin affinity of up to 2.5 kcal·mol⁻¹, indicating that personalized medical treatments that take into account individual mutation patterns could increase precision in the dosage of GPCR-targeting drugs.     

交联聚丙烯酸钠与交联羧甲基淀粉复配的高吸水性树脂的制备

采用交联聚丙烯酸钠和交联羧甲基淀粉进行复配,将两种原料按配比经混合、糊化、制片、粉碎、筛分制得复配高吸水性树脂成品.研究表明,最佳制备条件为:交联聚丙烯酸钠与交联羧甲基淀粉的质量比为8,糊化时的加水量为400g/g,糊化25min,制片温度为140℃.此产品将这两种高吸水性树脂组分的优缺点互补,生产成本低、安全性好,其吸蒸馏水倍率为800～1100倍,吸生理盐水的倍率为60～95倍.     

Rosmarinic Acid,as an NHE1 Activator,Decreases Skin Surface pH and Improves the Skin Barrier Function

Stratum corneum (SC) pH regulates skin barrier functions and elevated SC pH is an important factor in various inflammatory skin diseases. Acidic topical formulas have emerged as treatments for impaired skin barriers. Sodium proton exchanger 1 (NHE1) is an important factor in SC acidification. We investigated whether topical applications containing an NHE1 activator could improve skin barrier functions. We screened plant extracts to identify NHE1 activators in vitro and found Melissa officinalis leaf extract. Rosmarinic acid, a component of Melissa officinalis leaf extract, significantly increased NHE1 mRNA expression levels and NHE1 production. Immunofluorescence staining of NHE1 in 3D-cultured skin revealed greater upregulation of NHE1 expression by NHE1 activator cream, compared to vehicle cream. Epidermal lipid analysis revealed that the ceramide level was significantly higher upon application of the NHE1 activator cream on 3D-cultured skin, compared to application of a vehicle cream. In a clinical study of 50–60-year-old adult females (n = 21), application of the NHE1 activator-containing cream significantly improved skin barrier functions by reducing skin surface pH and transepidermal water loss and increasing skin hydration, compared to patients who applied vehicle cream and those receiving no treatment. Thus, creams containing NHE1 activators, such as rosmarinic acid, could help maintain or recover skin barrier functions.     

香辛料对亚硝酸钠的清除作用

研究花椒、八角、白胡椒香辛料对亚硝酸钠的清除作用,探讨提取液添加量、提取溶剂以及反应时间对清除效果的影响。结果表明,花椒和八角都以60%乙醇来提取作用效果较好,而白胡椒以无水乙醇来提取为佳;花椒、八角和白胡椒对亚硝酸钠的清除率都是随提取液添加量的增加呈现先增大后降低的趋势;与亚硝酸钠反应时间10min较为适宜;其中,花椒与八角按质量比1:2复配对亚硝酸钠的清除具有协同增效作用。     

糟卤制品保质期的研究

通过对真空包装的糟卤制品进行微波处理以减少制品的初始带菌数,同时添加化学防腐剂山梨酸钾、乳酸钠并把制成品存放在4℃的环境下以减缓制品中的微生物生长繁殖的速度,从而达到延长保质期的目的。     

Stability of protein‐stabilised β‐carotene nanodispersions against heating,salts and pH

BACKGROUND: Milk proteins are used in a wide range of formulated food emulsions. The stability of food emulsions depends on their ingredients and processing conditions. In this work, β‐carotene nanodispersions were prepared with selected milk‐protein products using solvent‐displacement method. The objective of this work was to evaluate the stability of these nanodispersions against heating, salts and pH. RESULTS: Sodium caseinate (SC)‐stabilised nanodispersions possessed the smallest mean particle size of 17 nm, while those prepared with whey‐protein products resulted in larger mean particle sizes (45–127 nm). Formation of large particles (mean particle size of 300 nm) started after 1 h of heating at 60 °C in nanodispersions prepared with SC. More drastic particle size changes were observed in nanodispersions prepared with whey protein concentrate and whey protein isolate. The SC‐stabilised nanodispersions were fairly stable against Na⁺ ions at concentrations below 100 mmol L^?1, but drastic aggregation occurred in ≥ 50 mmol L^?1 CaCl₂ solutions. Aggregation was also observed in whey protein‐stabilised nanodispersions after the addition of NaCl and CaCl₂ solutions. All sample exhibited the smallest mean particle size at neutral pH, but large aggregates were formed at both ends of extreme pH and at pH around the isoelectric point of the proteins. CONCLUSION: The nanodispersions prepared with SC were generally more stable against thermal processing, ionic strength and pH, compared to those prepared with whey proteins. The stable β‐carotene nanodispersions showed a good potential for industrial applications. Copyright © 2008 Society of Chemical Industry     

多聚磷酸钠对牛背最长肌盐溶蛋白质热诱导凝胶保水性和超微结构的影响

本文以牛背最长肌为材料，采用L25(5^6)正交设计研究了焦磷酸二氢二钠、三聚磷酸钠和六偏磷酸钠对牛背最长肌盐溶蛋白质热诱导凝胶保水性和凝胶超微结构的影响。结果表明，在相同的离子条件下，添加的酸性焦磷酸钠或焦磷酸二氢二钠和三聚磷酸钠对热诱导凝胶保水性有极显著的影响(p＜0．0001和p＜0．0071)，而六偏磷酸钠的影响则不显著(p＞0．05)。值得注意的是，焦磷酸二氢二钠与六偏磷酸钠的交互作用、焦磷酸二氢二钠与三聚磷酸钠的交互作用、三聚磷酸钠与六偏磷酸钠的交互作用对热诱导凝胶保水性的影响极显著(p＜0．0001)，且比三聚磷酸钠的方差贡献大。Duncan多重比较显示，在盐溶蛋白质提取过程中，添加0．3％焦磷酸二氢二钠可使凝胶的保水性平均达到98．375％，比焦磷酸二氢二钠添加量为0．1％、0．15％和0．2％的凝胶保水性(分别为81．652％、84．384％和78．987%)高，差异显著(p＜0．05)。扫描电镜研究结果显示，保水性不同的凝胶其超微结构表现出很大的差异。保水性为99．5％的凝胶其凝胶结构致密，均匀，网格细小，而且线条较纫，边缘平滑。而保水性为90%的凝胶则结构粗糙，表现为线条较粗，不均匀，蛋白质交联较少，网格大且不一致。线条多呈平行排列，或以聚集状态存在。