Production and structural features of a water-soluble polysaccharide from a mutant strain of Agrobacterium sp.

We have developed a mutant strain derived from Agrobacterium sp. ATCC 31750, which produces a water-soluble polysaccharide having potential utility to the food, feed, pharmaceutical and cosmetic industries. A high concentration of product (15 g/L) is obtained by 48 h cultivation of the mutant strain under optimized fermentation conditions. The water-soluble polysaccharide obtained from cultures of the mutant strain beta82 has Glc:Man:Gal in approximate molar ratios of 5.8:6.7:1.0. The molecular weight of the polysaccharide was determined to be approximately 1000 kDa by HPSEC analysis. Linkage analysis contained 3-Glcp, 3-Manp, terminal Glcp and terminal Manp, as well as a small proportion of 3- and 3,4-Galp, and 4,6-Manp residues. Based on analyses using FT-IR and ¹³C NMR spectrometers, most glycosidic bonds joining these sugar residues are of the α-type, and acetyl groups are apparently attached to the polymer chain at random.     

正交实验优选盐生藻多糖的提取工艺

以盐生藻为原料,盐生藻多糖得率为指标,运用稀酸、稀碱和蒸馏水为提取剂提取盐生藻多糖,得出合适的提取剂为稀酸.进一步的正交实验表明,盐生藻多糖的最适提取工艺为:提取75min,pH=4,固液比为1∶70,温度为95℃.     

角蛋白基药物载体的发展及应用探讨

从毛发中提取角蛋白，开发具有独特功能的角蛋白基药物载体材料，提高药物的活性和生物利用率，既能够增加毛发的利用价值，又能够实现节能减排，符合可持续发展战略要求。对毛发中提取角蛋白进行二硫键重建、自由基聚合、多糖改性和烷基化等改性处理，赋予角蛋白基药物载体优异地功能特性，进一步拓宽其作为角蛋白基药物载体的应用范围。角蛋白基药物载体可被加工成纳米粒子、纤维支架、水凝胶等各种形式用于药物的递送。作为一种高硫含量且具有良好细胞相容性的结构蛋白，角蛋白基药物载体在组织工程、再生医学等领域扮演着重要的角色。     

不同剂量A群脑膜炎球菌多糖菌苗的反应

应用30和50μg A 群脑膜炎球菌多糖菌苗,接种不同年龄组儿童和青少年、观察其全身和局部反应及大面积普种的异常反应。结果表明:接种30和50μg 菌苗后全身和局部反应轻微,两种剂量的接种反应无差别,仅有两个点接种两个不同年龄组时出现50μg 的全身及局部反应高于30μg。普种50多万人均未发生异常反应。     

桑黄多糖提取工艺优化、结构表征及抗氧化活性研究

目的 以临清桑黄为研究材料,采用热水浸提法制备桑黄多糖（Sanghuangporus sanghuang polysaccharide-hot water extraction, SSP-W）并研究其结构特征和抗氧化活性。方法 以SSP-W提取得率为指标,采用单因素和响应面试验对制备工艺进行优化,采用高效阴离子交换色谱-脉冲安培检测法（high performance anion exchange chromatography-pulsed amperometric detection,HPAEC-PAD）、傅里叶变换红外光谱（Fourier transform infrared spectroscopy,FT-IR）、扫描电镜和X-衍射对其结构进行初步表征。结果 最佳制备工艺为：提取时间2.4 h、提取温度95℃、液料比27:1（mL/g）,在此条件下,SSP-W提取得率为2.34%。其结构特征为：SSP-W以吡喃环为基本骨架,由Fuc、GlcN、Glc、Man 4种单糖组成。扫描电镜结果表明,SSP-W形状不规则,有明显的孔洞。X-衍射结果表明,SSP-W以结晶态聚合物和非结晶态聚合物的形式共存。抗氧化试验表明,SSP-W具有较强的抗氧化活性,其羟自由基和ABTS+自由基的EC50值（concentration for 50% of maximal effect,EC50）分别为492 μg/mL和75 μg/mL,当浓度为250 μg/mL时,ABTS+自由基清除率达到96.27%。结论 SSP-W是一种具有抗氧化潜力的活性物质。本研究结果将为临清桑黄多糖的精深加工和高值化利用提供科学依据。     

Acanthopanax senticosus Polysaccharide Enhances the Pathogen Resistance of Radiation-Damaged Caenorhabditis elegans through Intestinal p38 MAPK-SKN-1/ATF-7 Pathway and Stress Response

With the advancement of science and technology, humans are chronically exposed to ionizing radiation. It is crucial to look for efficient and low-toxic anti-radiation agents. Through preliminary screening, we found that Acanthopanax senticosus polysaccharide (ASPS) played a major role in regulating immune damage caused by radiation. The objective of this study was to apply the Caenorhabditis elegans—P. aeruginosa (PA14) infection model to illuminate the mechanism of ASPS increasing the pathogen resistance of radiation-damaged nematodes. Results indicated that ASPS (1 mg/mL) significantly enhanced the pathogen resistance of radiation-damaged nematodes by directly elevating the immune response of nematodes rather than by affecting the bacterial activity. Through further research on the p38 MAPK signaling pathway and related mutants, we found that ASPS functioned by the p38 MAPK pathway in the intestine, and SKN-1, ATF-7 as the downstream targets of PMK-1 participated the regulation of ASPS. In addition, ASPS markedly alleviated the stress status of damaged nematodes by regulating oxidative stress. Collectively, our findings suggest that ASPS enhances the pathogen resistance of radiation-damaged nematodes through the intestinal p38MAPK-SKN-1/ATF-7 pathway and stress response.     

Pure Chitosan Biomedical Textile Fibers from Mixtures of Low- and High-Molecular Weight Bidisperse Polymer Solutions: Processing and Understanding of Microstructure–Mechanical Properties’ Relationship

Natural polymers, as extracted from biomass, may exhibit large macromolecular polydispersity. We investigated the impact of low molar mass chitosan (LMW, DP_w~115) on the properties of chitosan fibers obtained by wet spinning of chitosan solutions with bimodal distributions of molar masses. The fiber crystallinity index (CrI) was assessed by synchrotron X-ray diffraction and the mechanical properties were obtained by uniaxial tensile tests. The LMW chitosan showed to slightly increase the crystallinity index in films which were initially processed from the bimodal molar mass chitosan solutions, as a result of increased molecular mobility and possible crystal nucleating effects. Nevertheless, the CrI remained almost constant or slightly decreased in stretched fibers at increasing content of LMW chitosan in the bidisperse chitosan collodion. The ultimate mechanical properties of fibers were altered by the addition of LMW chitosan as a result of a decrease of entanglement density and chain orientation in the solid state. An increase of crystallinity might not be expected from LMW chitosan with a still relatively high degree of polymerization (DPw ≥ 115). Instead, different nucleation agents—either smaller molecules or nanoparticles—should be used to improve the mechanical properties of chitosan fibers for textile applications.     

灵武长枣果粒对饼干烘焙品质及质构特性的影响

以灵武长枣为主要原料,低筋小麦粉、黄油、玉米油、白砂糖、泡打粉等为辅料,制作灵武长枣营养饼干,重点研究灵武长枣果粒的添加量(0、15、30、45、60、75 g)对饼干烘焙品质及相关物理特性的影响。实验结果表明:适量的添加灵武长枣粒,不仅可以改善饼干的感官品质,还可以改善饼干的质构、吸水率、色度。灵武长枣粒在低添加量时对饼干的感官品质具有改善作用,但当添加量超过45 g后,饼干的感官品质有所降低,灵武长枣粒的添加对饼干的硬度和咀嚼度有促进作用,弹性有下降的趋势,粘聚性和吸水率先升高后降低,对饼干的色度值影响较小。综合分析灵武长枣粒的添加量,以30～45g为宜。添加适量灵武长枣所制的饼干比一般饼干更酸甜可口,香气浓郁,口感酥脆,亮度适宜,色泽均匀,呈现棕黄色,相关物理特性均有所改善。     

超声波提取对麦冬多糖结构和抗氧化活性的影响

研究了超声波提取法在提取麦冬多糖过程中,对麦冬多糖的结构和抗氧化活性的影响.利用气相色谱法、环境扫描电子显微镜、原子力显微镜对其进行初步结构分析,然后在体外化学模拟条件下,测定它的总还原能力、对羟基自由基的清除作用及对Fe2诱发的脂质过氧化反应的抑制作用,并与传统热水提取法提取得到的麦冬多糖进行对比.超声波提取得到的麦冬多糖(SBP)和传统热水提取法提取得到的麦冬多糖(WBP)具有相同的单糖组成,都包括阿拉伯糖、甘露糖、葡萄糖及半乳糖,环境扫描电子显微镜的结果显示经超声提取的多糖的片状结构有不同程度的变小;原子力显微镜的扫描分析显示超声波使其糖链的分子片断变小,且SBP的抗氧化活性都要高于WBP.经超声波处理不会影响多糖的单糖组成,但会改变多糖的微观结构同时提高多糖的抗氧化活性.