Production of multienzyme by Bacillus aestuarii UE25 using ionic liquid pretreated sugarcane bagasse

The utilization of sugarcane bagasse (SB) in fermentation requires pretreatment processes to render fermentable components available to microorganisms. Pretreatment by using ionic liquids (ILs) is considered promising but the high cost is an impediment in its adoption, therefore, a mixture of IL pretreated and untreated SB was utilized to obtain bacterial multienzyme under solid-state fermentation (SSF). Bacillus aestuarii UE25, a thermophilic strain was utilized for that purpose. Fermentation conditions were optimized by adopting a central composite design. The model showed a good correlation between the predicted and the experimental values for amylase, xylanase, endoglucanase, and β-glucosidase. Volumetric and specific productivity of xylanase (4580 IU ml⁻¹ h⁻¹, 244.25 IU mg⁻¹ substrate, and 50 IU mg⁻¹ protein) were higher than the other enzymes. Changes in lignin content and reduced cellulose crystallinity due to IL pretreatment, followed by fermentation, were visualized by scanning electron microscopy, Fourier transform infrared spectroscopy, and Nuclear magnetic resonance. The strategy adopted by utilizing a mixture of IL pretreated and untreated SB under SSF proved promising to obtain high titers of different enzymes simultaneously. Since the bacterial strain used is thermophilic, therefore, the multienzyme can find its application in commercial processes which are carried out at high temperatures.     

Influence of Anion and Crosslink Density on the Ionic Conductivity of 1,2,3‐Triazolium‐Based Poly(ionic liquid) Polyester Networks

Covalently crosslinked, 1,2,3‐triazolium‐containing poly(ionic liquid) networks are prepared using Michael addition polymerization. Crosslink density and counteranion are varied in order to decipher the relationships between poly(ionic liquid) (PIL) structure and their thermal, mechanical, and conductive properties. An increase in acrylate concentration leads to a higher crosslink density, as reflected by an increase in the differential scanning calorimetry T _g, dynamic mechanical analyzer E ′, and a decrease in the ionic conductivity. Most notable with variable counteranion PILs is that analysis of the ionic conductivity curves reveals a common “crossover” point at ≈85 °C (same acrylate:acetoacetate ratio). Below this crossover temperature, the ionic conductivity appears to be more dependent upon network/polymer chain dynamics. Above 85 °C, the conductivity correlates best with the size of the counteranion. All of the PILs reported here exhibit good ionic conductivities (10⁻⁶ to 10⁻⁸ S cm⁻¹@25 °C, 30% RH), supporting the notion that 1,2,3‐triazolium‐containing PILs represent a vastly underrated electroactive material platform.     

纳米羟基磷灰石/聚酰胺66多孔材料制备和生物安全性初步评价

采用注塑方法，以医用纳米羟基磷灰石僳酰胺66（n-HA／PA66）复合材料为原料，使用专用发泡剂，制备出了一种具有贯通孔，平均孔隙尺寸约为500衄1的多孔材料，并参照GB／T16886和GB／T16175标准方法，对其生物安全性进行了相关评价。细胞毒性试验、致敏试验、热原试验和溶血试验结果表明本研究制备的多孔n-HA／PA66复合材料无细胞毒性、无致敏性、无热原反应，溶血率为0．59％（〈5％），可初步认为n—HA／PA66多孔材料具有良好的生物安全性，可用于骨组织修复。     

Nitrogen‐Doped Carbon Electrodes: Influence of Microstructure and Nitrogen Configuration on the Electrical Conductivity of Carbonized Polyacrylonitrile and Poly(ionic liquid) Blends

In this paper, the preparation of nitrogen‐doped carbon fibers and thin films from mixtures of polyacrylonitrile (PAN) and a poly(ionic liquid) (PIL) by electrospinning and dip‐coating is presented, respectively, followed by carbonization at distinct temperatures. The poor processability of the PIL into sub‐micrometer fibers by electrospinning—originating from its high charge density and meanwhile low glass transition temperature—is successfully circumvented by using blends of PAN and PIL. The electrospun fiber mats exhibit a high surface‐to‐volume‐ratio with an intrinsically macroporous through‐pore structure and a uniform fiber diameter after carbonization. Physicochemical characterization of the N‐doped carbons by means of scanning electron microscopy, algorithmic X‐Ray diffraction analysis, nitrogen physisorption, thermogravimetry, elemental analysis, energy‐dispersive X‐ray, and X‐ray photoelectron spectroscopy gives insight into their physical and electrical structures. Impedance measurements on carbonized PIL/PAN‐blends reveal high electrical conductivities up to 320 S cm^?1, which are attributed to the incorporation of predominantly quaternary‐graphitic nitrogen atoms into the carbon network during carbonization. The results indicate that the electrical conductance of the N‐doped carbons strongly depends on the chemical environment of the inserted nitrogen atoms, the microstructural evolution of π‐conjugated carbon network—which in turn correlate with the carbonization temperature—and the chemical composition.

     

Investigations on cytotoxic and genotoxic effects of laser printer emissions in human epithelial A549 lung cells using an air/liquid exposure system

Exposure to emissions from laser printers during the printing process is commonplace worldwide, both in the home and workplace environment. In the present study, cytotoxic and genotoxic effects of the emission from five low to medium‐throughput laser printers were investigated with respect to the release of ozone (O₃), volatile organic compounds (VOC), particulate matter (PM), and submicrometer particles (SMP) during standby and operation. Experiments were conducted in a 1 m³ emission chamber connected to a Vitrocell® exposure system. Cytotoxicity was determined by the WST‐1 assay and genotoxicity by the micronucleus test in human A549 lung cells. The five laser printers emitted varying but generally small amounts of O₃, VOC, and PM. VOC emissions included 13 compounds with total VOC concentrations ranging from 95 to 280 μg/m³ (e.g., 2‐butanone, hexanal, m,p‐xylene, and o‐xylene). Mean PM concentrations were below 2.4 μg/m³. SMP number concentration levels during standby ranged from 9 to 26 particles/cm³. However, three of the printers generated a 90 to 16 × 10³‐fold increase of SMP during the printing process (maximum 294,460 particles/cm³). Whereas none of the printer emissions were found to cause cytotoxicity, emissions from two printers induced formation of micronuclei (P < 0.001), thus providing evidence for genotoxicity. As yet, differences in biological activity cannot be explained on the basis of the specific emission characteristics of the different printers. Because laser printing technology is widely used, studies with additional cytogenetic endpoints are necessary to confirm the DNA‐damaging potency and to identify emission components responsible for genotoxicity. Environ. Mol. Mutagen., 2012. © 2011 Wiley Periodicals, Inc.     

应用变性高效液相色谱技术研究肿瘤转移抑制基因KAI1/CD82多态与结直肠癌发病及转移的相关性

目的 研究肿瘤转移抑制基因KAII/CD82第8内含子IVS(8)6C11A/6T11G多态与结直肠癌发病及转移的相关性.方法 提取135例健康人、115例结直肠癌患者的外周血DNA,收集其相应的临床及病理资料,应用变性高效液相色谱技术,采用病例对照分组研究统计分析KAI1基因第8内含子剪接区域多态与结直肠癌发病及转移的相关性.结果 KAI1/CD82基因IVS(8)6T11G突变基因型检出率在正常人群为30.9%(84/135),结直肠癌患者中为31.3%(72/155),两者的差异无统计学意义(P=0.963);在结直肠癌低龄(＜50岁)和高龄(≥50岁)患者之间以及性别之间差异均无统计学意义(均P＞0.05);在常见的病理类型管状/管状乳头状腺癌、黏液腺癌中差异亦无统计学意义(P=0.633);在病理分级中有一定的差异性,但无统计学意义(P=0.267),而在有无淋巴结转移之间,两者差异有统计学意义(P.0.032)[6C11A有转移62.5%(80/128),无转移76.5%(78/102);6T11G有转移37.5%(48/128),无转移23.5%(24/102)].结论 肿瘤转移抑制基因KAI1/CD82第8内含子剪接区域多态与结直肠癌的发病、病理类型无关,但可能影响肿瘤的淋巴结转移,提示KAI1/CD82基因IVS(8)6C11A/6T11G多态筛查可能成为结直肠癌患者预后风险评估的指标.     

Alteration of N-glycosylation in the kidney in a mouse model of systemic lupus erythematosus: relative quantification of N-glycans using an isotope-tagging method

Changes in the glycan structures of some glycoproteins have been observed in autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis. A deficiency of alpha-mannosidase II, which is associated with branching in N-glycans, has been found to induce SLE-like glomerular nephritis in a mouse model. These findings suggest that the alteration of the glycosylation has some link with the development of SLE. An analysis of glycan alteration in the disordered tissues in SLE may lead to the development of improved diagnostic methods and may help to clarify the carbohydrate-related pathogenic mechanism of inflammation in SLE. In this study, a comprehensive and differential analysis of N-glycans in kidneys from SLE-model mice and control mice was performed by using the quantitative glycan profiling method that we have developed previously. In this method, a mixture of deuterium-labelled N-glycans from the kidneys of SLE-model mice and non-labelled N-glycans from kidneys of control mice was analysed by liquid chromatography/mass spectrometry. It was revealed that the low-molecular-mass glycans with simple structures, including agalactobiantennary and paucimannose-type oligosaccharides, markedly increased in the SLE-model mouse. On the other hand, fucosylated and galactosylated complex type glycans with high branching were decreased in the SLE-model mouse. These results suggest that the changes occurring in the N-glycan synthesis pathway may cause the aberrant glycosylations on not only specific glycoproteins but also on most of the glycoproteins in the SLE-model mouse. The changes in glycosylation might be involved in autoimmune pathogenesis in the model mouse kidney.