An Air‐Supported Liquid Crystal System for Real‐Time and Label‐Free Characterization of Phospholipases and Their Inhibitors

A new air‐supported liquid crystal (LC) system for analyzing interfacial phenomena that occur based on the molecular interaction between LCs and adsorbed molecules of interest at the aqueous/LC interface is reported. Compared with existing LC‐based detection systems, the miniature system reported here requires less sample and involves simpler preparation. Using this system, the enzymatic hydrolysis of various phospholipases such as phospholipase A₂ (PLA₂), phospholipase C (PLC) and phospholipase D (PLD) are characterized. The hydrolysis of phospholipid monolayers self‐assembled at aqueous/LC interface induces an orientational response from the LCs. As a result, an optical signal that reflects the spatial and temporal distribution of phospholipids during the enzymatic reaction can be generated in a real‐time manner. When well‐known phospholipase inhibitors are introduced together with respective phospholipases, no orientational response of LCs is observed. In the case of inhibitors MJ33 and compound 48/80, cross‐inhibitions among phospholipases are also observed. This work demonstrates that the air‐supported LC system provides a facile label‐free assay for characterizing phospholipase activities and for screening enzyme inhibitors. It could potentially be useful for different high throughput and cost‐effective enzyme screening assays.     

Chitosan and marine phospholipids reduce matrix metalloproteinase activity in myeloma SP2 tumor‐bearing mice

An animal experiment was conducted to assess the antitumor effects of chitosan‐coated liposomes on myeloma SP2. The animal experimental groups designed for myeloma SP2 tumor‐bearing BALB/c mice were provided with five different drinks: (I) control (double‐distilled water); (II) squid phospholipid liposomes alone 1.0 mg/mL; (III) chitosan alone 5.0 mg/mL; (IV) squid phospholipid liposomes 1.0 mg/mL with chitosan 5.0 mg/mL in the form of a simple mixture; and (V) squid phospholipid liposomes 1.0 mg/mL coated with chitosan 5.0 mg/mL. At 20 days after implantation of the myeloma SP2 cells into mice, oral administration of the experimental drinks was provided for 35 days. There was significant suppression of tumor growth when chitosan and squid phospholipids were administered simultaneously in a simple mixture or as chitosan‐coated liposomes. Matrix metalloproteinase (MMP)‐2 and MMP‐9 activity was significantly less in the serum of mice that consumed chitosan‐coated liposomes than in control mice. We found that decreased tumor burden was related to MMP secretion. Therefore, chitosan‐coated marine phospholipid liposomes might be useful as potential agents for the treatment of myeloma SP2.     

Fractionation of soybean phospholipids by high-performance liquid chromatography with an evaporative light-scattering detector

Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from 23 soybean lines with a wide range of fatty acid compositions were resolved into seven fractions by high-performance liquid chromatography (HPLC). Fraction identities were assigned from fatty acid compositions determined by gas chromatography (GC). A mass detector, i.e., an evaporative light-scattering detector, was used for HPLC quantification. The detector response was a power function of PC and PE concentrations. Various correction methods were applied to the detector response to obtain the best agreement between phospholipid (PL) fatty acid compositions determined by GC and that calculated from the corrected HPLC fraction percentages. The corrected HPLC fraction composition also was compared with that calculated from stereospecific distribution data using a 1-random-2-random hypothesis. Correlation between PL-fatty acid and HPLC-fraction percentages showed that genetic modification of soybean oil composition caused changes in PL species, which alter physical properties and may alter the physiological functions of PL in biomembranes.     

Drying of Herbal Product in Closed System

A new product from a low temperature drying method that reduces the loss of highly volatile essential oils is presented. The proposed drying method consists of evaporation/sublimation of water and aromatic substances in a dryer with a closed drying agent cycle. In parallel, the evaporated compounds are continuously condensed in a heat exchanger. As a result of the drying process, high-quality dried plants and Fluidolat as liquid phase containing water and volatile organic compounds are obtained. The aim of presented investigations was to optimize the developed technology for the herb lavender.     

红线宽度变化时缓和曲线边线展宽方法

两条不等宽的道路相对接时,如果中线是缓和曲线,特别是在内边线加宽的情况下,边线平滑连接涉及复杂的曲线解算。本文就此问题阐述解决的思路和方法。     

Efficacy of essential oil extracts in inhibiting mould growth on panel products

The aim of this research was to exploit the chemical properties of natural products to control the incidence and extent of mould growth in houses. The screening of antimould activities of seven essential oil extracts showed that most of the extracts completely inhibited the growth of all three test mould at the concentration of 1% w/v on nutrient medium, whereas, different fractions of manuka oil showed varied activity. Subsequently, using both mycological and scanning electron microscopy, the testing of selected extracts on two different types of gypsum board finished with either paint or wall-paper, confirmed the antimould activity of eugenol, thymol and cinnamaldehyde against Penicillium corylophilum. This study identified certain essential oil extract as a potential mould inhibitor for panel products which is one of the most common mould habitats in the building environment. Mould growth in residential houses is a major concern and chemical fungicides commonly used to control the growth of mould are not often appropriate for indoor applications. Natural alternatives such as essential oils are desirable for this application. Knowledge gained through this research should lead to new niche panel product development to create healthier housing.     

磷脂含量及组成的分析检测方法

综述了定量分析磷脂组成及含量的分析方法 ,重点介绍了TLC和HPLC方法 ,并列举了HPLC分析方法的不同类型检测器。另外还介绍了核磁共振、红外光谱等技术在磷脂的分析和检测中的应用。     

超临界CO_2萃取香料精油的研究

本文对熏衣草、百里香、野百里香和迷迭香４种香料单独或两种香料混合超临界ＣＯ２萃取和分级分离香料精油的工艺可行性，以及采用ＧＣ，ＧＣ－ＭＣ对萃取物的主要成分分析进行了初步研究。从两种香料混合物中革取所获产率等于从每种香料所获产率之平均值，混合萃取明显提高精油和树脂两种产品的分离效率，两种香料混合物的萃取物所含的主要成分与两种香料单独萃取的成分相同，但浓度有明显差别。     

Effect of processing methods on product characteristics,lipid, fatty acid composition and oxidative stability of smoke-dried beef

Smoke-dried beef was pre-processed with water or by pressure cooking, weight losses were 50 and 54% respectively, with the rate of drying faster in the latter. There was a greater loss of total lipid and triglycerides in pressure cooked samples but the reverse was true for the phospholipids. The proportions of saturated and monoenoic fatty acids were slightly higher in the water cooked products although total unsaturation was slightly lower, the values being 37 and 39%, respectively. The fatty acid composition of the phospholipids was similar for both treatments except that the levels of polyenoic fatty acids were 16.4 and 14.43%, respectively in water and pressure cooked samples. Of the polyenes C20:4 accounted for about 75% of the fatty acids in the water cooked samples, compared with 40% with pressure cooking. After 60 weeks of storage at room temperature, pressure cooked samples were found to be more stable oxidatively: malonaldehyde was the principal oxidative by-product in both treatments.     

Studies on the effects of microwave drying and cabinet tray drying on the chemical composition of volatile oils of garlic powders

Garlic cloves in the form of bits were dried in a cabinet tray dryer and a microwave dryer, and pulverized to obtain free flowing powder. The volatile oil was obtained by hydro-steam distillation method. Fresh cloves and the powders resulting from the two drying methods were used for obtaining the volatile oil, which was analyzed by GC-MS. The studies were mainly restricted to comparing the effect of drying methods on the volatile oil composition of the powders. Although the drying time was reduced considerably from 8 h in a cabinet dryer to 0.25 h in a microwave dryer, essential oil yield and color values were lower, and flavor quality varied considerably. The relative concentrations of major peaks such as diallyl disulfide, diallyl tetrasulfide increased in both the drying methods, and it was more so in microwave-dried samples. However, the concentrations of the other two major peaks, diallyl trisulfide and allyl methyl trisulfide, decreased in both drying methods, and they were lower in microwave-dried samples. Hunter values of L and b were lower for samples obtained by microwave drying as compared to those of cabinet-dried samples.