Construction of the mutant strain in Aspergillus oryzae 3.042 for abundant proteinase production by the N+ ion implantation mutagenesis

Because of secreting large amounts of enzymes, Aspergillus oryzae was widely used in the fermentation of soy sauce in many Asian countries. Here, N⁺ ion implantation mutagenesis was applied to improve the ability of A. oryzae to secrete acid protease. Several mutants were screened using three kinds of plates (Casein medium, Czapek’s medium and carboxymethyl cellulose medium agar plates). Compared with the other mutants, the mutant A100‐8 could secrete the most protease. Acid protease activity of A100‐8 was enhanced about 44.1% at 36 h by koji fermentation test. In addition, A100‐8 was stable by periodically subculturing and maintaining on the agar slant. The mRNA expression levels of two kinds of acid protease (serine carboxypeptidase and aspartyl protease) were measured by RT‐PCR at different periods. Serine carboxypeptidase and some kinds of aspartyl protease of A100‐8 were significantly (P < 0.01) expressed higher than the control at all times.     

Micronized drug powders in binary mixtures and the effect of physical properties on aerosolization from combination drug dry powder inhalers

Objectives: To evaluate physicochemical properties of two micronized drugs, salbutamol sulfate (SS) and beclomethasone dipropionate (BDP) prepared as dry powder inhalation physical blends. Methods: Five different blends of SS:BDP ratios of 0:100, 25:75, 50:50, 75:25, and 100:0 (w/w) were prepared. Aerosolization performance was evaluated using a multistage impinger and a Rotahaler® device. Results: The median SS particle diameter was larger than BDP (4.33?±?0.37 µm compared to 2.99?±?0.15 µm, respectively). The SS appeared to have a ribbon-like morphology, while BDP particles had plate-like shape with higher cohesion than SS. This was reflected in the aerosolization performance of the two drugs alone, where SS had a significantly higher fine particle fraction (FPF) than BDP (12.3%, 3.1% and 2.9%, 0.2%, respectively). The study of cohesion versus adhesion for a series of SS and BDP probes on SS and BDP substrates suggested both to be moderately adhesive, verified using scanning Raman microscopy, where a physical association between the two was observed. A plot of loaded versus emitted dose indicated that powder bed fluidization was significantly different when the drugs were tested individually. Furthermore, the FPF of the two drugs from the binary blends, at all three ratios, were similar. Conclusions: Such observations indicate that when these two drugs are formulated as a binary system, the resulting powder structure is altered and the aerosolization performance of each drug is not reflective of the individual drug performance. Such factors could have important implications and should be considered when developing combination dry powder inhalation systems.     

Effect of ion irradiation on the properties of carbon nanotube buckypapers

Optical, electrical and structural properties of argon (Ar) ion-irradiated buckypapers of multi-walled carbon nanotube (MWCNT) at various doses prepared by a vacuum filtration method were investigated. It was found that the direct current (DC) conductivity and absorption spectra in the visible range were decreased with an increasing Ar ion irradiation dose. A subsequent heating of nanotube buckypapers at 800 K in a vacuum at each irradiation dose improved the conductivity of buckypapers, whereas optical absorption was unchanged. Moreover, the graphite structure of MWCNTs was transformed to amorphous structure with an increasing Ar ion irradiation dose. The decrease of optical absorption and electrical conductivity of MWCNT buckypaper at room temperature can be ascribed to the increase of defects in the irradiated MWCNTs.     

Ion Exchange Resin Applied to Obtain Clarified Cashew Juice

The condensed tannins present in cashew apple juice provide high astringency, which is undesirable for this product. This study aimed to remove the cashew apple juice tannins by ion exchange for obtaining the clarified cashew apple juice (cajuína). Two strong base resins were used (macroporous and gel type). The effect of the process variables: temperature, resin:juice ratio, and stirring speed were determined. The macroporous resin presented better results with condensed tannins removal up to 80% in optimal conditions (30°C, ratio 1:6, 122 rpm). The cajuína obtained was clear and translucent, with low astringency, acidity, and °Brix according to Brazilian legislation.     

当归红芪超滤物对重离子12C6+辐射肝癌细胞DNA损伤修复的影响

将人肝癌H22细胞分成4组,分别为对照组、药物组(100 mg/L)、辐射组(2 Gy)及联合组(100 mg/L药物 + 2 Gy照射),采用CCK-8法、单细胞凝胶电泳、γ-H2AX免疫荧光原位杂交技术以及Western Blotting印迹法,研究当归红芪超滤物(Radix Angelicae Sinensis and Radix Hedysari, RAS-RH)对重离子¹²C⁶⁺辐射引起人肝癌H22细胞DNA损伤修复的影响和其可能的机制。结果表明,在0～72 h和给药剂量为5～200 mg/L范围内,RAS-RH对人肝癌H22细胞的增殖抑制作用具有时间和剂量依赖性,其20%抑制浓度IC₂₀为(117.6±2.15)mg/L;单细胞凝胶电泳显示联合组头部DNA含量低于辐射组,而尾部DNA含量、尾距TM、Olive尾距OTM均高于辐射组;γ-H2AX免疫荧光原位杂交技术发现RAS-RH不增加重离子¹²C⁶⁺辐射引起的DNA损伤,但在2—12 h,DNA双链断裂的γ-H2AX foci修复作用被RAS-RH抑制,DNA损伤持续存在;Western Blotting显示RAS-RH通过下调Ku70/80及Rad51的蛋白表达,抑制γ-H2AX的聚集。以上结果说明RAS-RH对人肝癌H22细胞的辐射增敏作用可能是下调DNA损伤修复相关因子Ku70/80及Rad51的表达。     

Performance of C18 Derivatized Silica Gels: A Structure-Performance Study

Abstract

Significant performance differences in the separation of desamido-insulin from insulin and of amitriptyline from imipramine have been found for five, macroscopically similar, preparative C18 silica materials. Structure-performance relations have been used to understand this difference. Physical measurements on the unpacked silica gels as well as chromatographic measurements have been carried out. The latter measurements comprise: hydrophobicity, metal impurity, steric selectivity and silanol activity. The performance difference could not be explained by the difference in hydrophobicity, steric selectivity or metal impurity between the materials. Instead a correlation between the silanol ion exchange activity and the selectivity could be found. The highest performance was found under conditions where the silanol groups have a moderate activity. For the separations considered in this work, the silanol groups have a beneficial effect.     

Effects of chloride,thiocyanate and sulphate salts on β‐lactoglobulin–pectin associative complexes

Protein–polysaccharide complexes are used to improve protein stability and encapsulate high‐value ingredients, yet the influence of different salts on their formation has not been investigated. Using light scattering and turbidimetry, effects of chloride, sulphate and thiocyanate salts on β‐lactoglobulin and pectin complexes (protein/pectin ratio = 2:1 and 4:1) were determined in relation to effects of pH and ionic strength. Effects of anions on complex formation were significant at 25 mmol kg^?1 added ionic strength. Cation effects were not significant. At 100 mmol kg^?1 ionic strength, pH of complex formation increased with sulphate salts (pH 5.1) relative to chloride and thiocyanate salts (pH 4.9), while pH of coacervation increased with sulphate salts (pH 4.7) and decreased with thiocyanate salts (pH 4.4) relative to chloride salts (pH 4.6). Pure β‐lactoglobulin stability was otherwise reduced with thiocyanate salts below pH 5, implying a significant effect of pectin interactions.     

拟薄水铝石中硫酸根的存在形式及其对拟薄水铝石性质的影响

A series of pseudo-boehmite samples with their sulfate radicals（SO42-） concentration ranging from 0.9% to 3.0%were prepared by the reaction of NaAlO2 solution on Al2（SO4）3 solution. The existing form of sulfate radicals was investigated.Results have shown that sulfates in pseudo-boehmite included two parts, the soluble sulfate radicals and the insolublesulfate radicals, which accounted for 99% of the total amount of sulfate radicals. XRD, low-temperature N2-adsorption, andTEM were used to characterize the properties of these pseudo-boehmite samples. Results have shown that the relative crystallinityand crystal size of pseudo-boehmite decreased with the increase of sulfate radicals in the support. In the meanwhile,the bound water content in pseudo-boehmite increased. The TEM images of pseudo-boehmite indicated that the pseudoboehmitewas prone to become amorphous hydrated alumina. However, the effect of sulfate content on the specific surfacearea and pore structure of aluminium oxide was insignificant.     

化学示踪连通试验在矿井充水条件探查中的应用

为获取地下水流速和渗透系数等水文地质参数、查清含水层水力联系、查明矿井充水条件，在内蒙古某矿设计实施了化学示踪试验。通过对国内外化学示踪试验资料整理、统计分析，总结出化学示踪剂用量与投放距离、含水层性质的经验关系式，并对本次示踪剂用量做出了评价。同时，对试验中监测点水中均未出现Cl-浓度增高现象进行了科学解释，提出类似含Cl-示踪剂中的某些离子可能被地下岩层特定矿物质吸附时，只要化学试剂中的一种离子能达到试验效果，且具有成本低、易获取等特点，即可选择其作为示踪剂的观点。