2,3-丁二醇的絮凝预处理研究

为使生物法制备2,3-丁二醇的后续分离纯化过程顺利进行,研究了絮凝法预处理2,3-丁二醇发酵液。选用10种絮凝剂,以絮凝率和蛋白去除率为指标,分别考察了絮凝剂、质量浓度、pH值、温度和搅拌时间等条件对2,3-丁二醇发酵液的絮凝效果、浓度及后续萃取过程的影响,得出较优絮凝条件:以氯化铁为絮凝剂,质量浓度为23 g/L,pH值5.1,温度为20—50℃,搅拌时间15 m in,静置20 m in。在此工艺条件下,2,3-丁二醇的絮凝率和蛋白去除率均可高达98%以上,为后续的分离纯化过程奠定基础。     

高分子量丙烯酸钠聚合物絮凝淀粉废水的研究

研究了高分子量丙烯酸钠聚合物絮凝剂用量、助凝剂用量、体系pH值以及搅拌速率等因素对淀粉废水絮凝效果的影响。在最佳絮凝条件下CODCr去除率可达50%以上,浊度去除率可达90%以上,所得到的絮体无毒,可进一步回收利用。     

甘油发酵液的絮凝除菌研究

利用高分子絮凝剂絮凝去除甘油发酵液中的菌体，考察了pH值，絮凝剂用量，絮凝温度对絮凝效果的影响，结果表明：适宜的絮凝条件为pH=5-10，温度30－40℃，ρ（絮凝剂）＝0．7－0．8g/L，此时菌体絮凝剂（FR）可达90％以上。经絮凝处理后，滤速为未加絮凝剂的2．5－4．5倍；滤液中菌体去除率达100％，固形物的回收量为未知絮凝剂的2．1倍，滤饼的含湿量由71％增加到78％。     

微生物絮凝剂的提纯及絮凝条件的优化

从污泥中分离并筛选出一株具有高絮凝活性的菌株,为了获得纯度高、性质稳定的絮凝剂,本文对其提纯工艺和絮凝条件进行了研究.实验结果表明,采用丙酮法对发酵液进行提纯,产量可达38.4 mg/L.该菌株产生高絮凝活性的最佳絮凝条件为.pH=7.0,絮凝剂投加量为1 mL,助凝剂为1％的CaCl2溶液、投入量为1.0 mL,先将溶液快搅1 min,再慢搅3 min后,对100 mL 1 g/L高岭土悬浮液的絮凝率可达90％以上,说明该微生物絮凝剂具有很好的应用前景.     

明矾-壳聚糖复合絮凝处理含油废水的研究

利用无机絮凝剂明矾和有机絮凝剂壳聚糖复合作用对含油废水进行絮凝处理。对影响絮凝过程的主要因素,如温度、溶液pH值、絮凝剂用量及复合絮凝剂配比进行了实验研究,结果表明:最佳絮凝条件为温度40℃和pH值6~7,复合絮凝剂明矾:壳聚糖配比为3∶1,絮凝剂用量为0.5 g/L时,絮凝效果最好。处理后的含油污水澄清度高,除油率可达到97%。     

葡萄糖和木糖双底物生物合成2,3-丁二醇的条件优化

针对利用葡萄糖和木糖合成2,3-丁二醇的Klebsiella pneumoniae XJ-Li菌,优化培养基组成与发酵条件,围绕五、六碳糖共代谢的特点,探讨简单可行的代谢调控方法. 结果表明,60 g/L葡萄糖和40 g/L木糖为碳源,5.75 g/L NH4H2PO4为氮源,pH值维持在5.5,培养温度38℃, 2,3-丁二醇浓度可达19.24 g/L. 确定了pH值调控和外源添加维生素C的调控方式,通过调节发酵过程中pH值于5.5左右,使2,3-丁二醇的产量提高了16.4%;添加60 mg/L维生素C调节培养基的氧化还原状态,可使2,3-丁二醇的产量提高44.3%,批式发酵48 h, 2,3-丁二醇终浓度可达33.47 g/L.     

两性壳聚糖复合絮凝剂对印染废水的絮凝性能研究

以两性壳聚糖为絮凝剂处理了丝绸印染废水,并与羧甲基壳聚糖、壳聚糖季铵盐、聚合氯化铝和聚丙烯酰胺的絮凝性能进行了比较,研究了废水的pH、絮凝剂的质量浓度、助凝剂的类型及其与两性壳聚糖的复配比对其絮凝性能的影响.结果表明,两性壳聚糖的絮凝性能优于羧甲基壳聚糖、壳聚糖季铵盐、聚合氯化铝和聚丙烯酰胺;在pH为5.0～6.0、絮凝剂两性壳聚糖的质量浓度为90 mg/L时,废水的COD去除率可达76.8%;助凝剂的加入可提高两性壳聚糖对COD的去除率.在m(助凝剂):m(絮凝剂)=40、混凝剂的加入量为2 500～3 000 mg/L时,废水COD的去除率可在80%以上.     

枯草芽孢杆菌对细粒煤的絮凝实验研究

介绍了枯草芽孢杆菌的生物特性,利用该菌对细粒煤进行絮凝实验研究,结果表明,菌体本身对细粒煤溶液的絮凝作用要强于发酵液及上清液,絮凝率达84.0%;添加助凝剂Fe2+、Ca2+可以提高该菌的絮凝率,其中Ca2+可以使絮凝率达到95.8%;细粒煤溶液的pH值为9时絮凝率最高,可达97.3%。     

絮凝与膜超滤耦合预处理谷氨酰胺发酵液

采用絮凝与膜超滤相耦合的方法对谷氨酰胺发酵液进行预处理 ,详细讨论了壳聚糖做絮凝剂去除菌体和膜超滤去除蛋白和多糖等的效果及影响因素。实验表明 ,在壳聚糖质量浓度为80 0～ 10 0 0 g/m3 ,发酵液为 pH =4 0～ 6 0 ,温度 2 5℃左右 ,快速搅拌与慢速搅拌相结合的操作条件下 ,絮凝效果最佳 ,菌体去除率超过 95 %。采用截留相对分子质量为 6 0 0 0的中空纤维膜超滤絮凝后的谷氨酰胺发酵液 ,蛋白去除率 70 4 % ,总有机碳降低 5 7 3% ,大部分的蛋白和多糖被除掉。该预处理方法具有工业应用的前景     

生物絮凝剂产生菌的筛选及絮凝处理靛蓝印染废水的研究

从活性污泥中分离出22株菌株,筛选得到具有絮凝活性的菌株14株,其中FJ-7、FJ-15絮凝活性较高。将两株絮凝剂产生菌分别纯培养及以体积比1∶1比例混合培养,发现混合培养发酵液对高岭土悬浊液的絮凝效果优于各菌株的纯培养发酵液。利用此混合发酵液对靛蓝印染废水进行絮凝处理,考察了生物絮凝剂和助凝剂CaC l2的用量、废水pH对脱色效果的影响。在混合菌发酵液和助凝剂CaC l2的体积分数分别为5%和4%、废水pH=8.0的最适脱色条件下,混合发酵液对靛蓝废水的脱色率可达87.2%。     

饲养细胞用于挽救濒死的珍稀贴壁细胞

目的挽救濒于死亡的珍稀贴壁细胞。方法将濒于死亡的RINm5F细胞接种到一定量体外培养的小鼠腹腔细胞中,经过一段时间的培养,待RINm5F细胞逐渐长成岛状时,传代并再连续添加2次饲养细胞培养后,传2代,冻存。结果濒于死亡的RINm5F细胞与饲养细胞共培养,随着时间的延长,细胞生长速度加快,饲养细胞逐渐死亡,再经2次与饲养细胞共培养,细胞已恢复正常生长,冻存后复苏生长状态良好。结论添加饲养细胞的方法可用于挽救濒于死亡的细胞。     

From Stem Cells to Bone-Forming Cells

Bone formation starts near the end of the embryonic stage of development and continues throughout life during bone modeling and growth, remodeling, and when needed, regeneration. Bone-forming cells, traditionally termed osteoblasts, produce, assemble, and control the mineralization of the type I collagen-enriched bone matrix while participating in the regulation of other cell processes, such as osteoclastogenesis, and metabolic activities, such as phosphate homeostasis. Osteoblasts are generated by different cohorts of skeletal stem cells that arise from different embryonic specifications, which operate in the pre-natal and/or adult skeleton under the control of multiple regulators. In this review, we briefly define the cellular identity and function of osteoblasts and discuss the main populations of osteoprogenitor cells identified to date. We also provide examples of long-known and recently recognized regulatory pathways and mechanisms involved in the specification of the osteogenic lineage, as assessed by studies on mice models and human genetic skeletal diseases.     

Density-Dependent Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Parathyroid-Hormone-Releasing Cells

Mesenchymal stem cells (MSCs) can differentiate into endoderm lineages, especially parathyroid-hormone (PTH)-releasing cells. We have previously reported that tonsil-derived MSC (T-MSC) can differentiate into PTH-releasing cells (T-MSC-PTHCs), which restored the parathyroid functions in parathyroidectomy (PTX) rats. In this study, we demonstrate quality optimization by standardizing the differentiation rate for a better clinical application of T-MSC-PTHCs to overcome donor-dependent variation of T-MSCs. Quantitation results of PTH mRNA copy number in the differentiated cells and the PTH concentration in the conditioned medium confirmed that the differentiation efficiency largely varied depending on the cells from each donor. In addition, the differentiation rate of the cells from all the donors greatly improved when differentiation was started at a high cell density (100% confluence). The large-scale expression profiling of T-MSC-PTHCs by RNA sequencing indicated that those genes involved in exiting the differentiation and the cell cycle were the major pathways for the differentiation of T-MSC-PTHCs. Furthermore, the implantation of the T-MSC-PTHCs, which were differentiated at a high cell density embedded in hyaluronic acid, resulted in a higher serum PTH in the PTX model. This standardized efficiency of differentiation into PTHC was achieved by initiating differentiation at a high cell density. Our findings provide a potential solution to overcome the limitations due to donor-dependent variation by establishing a standardized differentiation protocol for the clinical application of T-MSC therapy in treating hypoparathyroidism.     

特异性抗原致敏的DC-CIK细胞对肿瘤细胞的杀伤效应

目的检测特异性抗原致敏的DC-CIK细胞对恶性肿瘤细胞的杀伤效应。方法采用肿瘤抗原致敏的DC与CIK细胞共培养,分析其免疫表型,并用MTT染色法检测其对肿瘤细胞的杀伤力。结果所获得DC-CIK细胞的CD3异质性T细胞群,对肾透明细胞癌786-0和前列腺癌PC-3细胞的杀伤率分别为70.64%和65.65%。结论DC-CIK细胞对肾透明细胞癌786-0细胞和前列腺癌PC-3细胞具有较强的杀伤效应。     

骨髓间充质干细胞向视网膜神经节样细胞的分化

目的探讨乳鼠视网膜细胞条件分化液诱导骨髓间充质干细胞(BMSCs)的神经分化情况,以期为视网膜退行性疾病提供治疗方案。方法体外分离培养Wistar大鼠乳鼠BMSCs,观察BMSCs的增殖情况并进行鉴定;制备乳鼠视网膜细胞条件分化液,以其诱导BMSCs,观察BMSCs的神经分化情况,并行免疫组化鉴定。结果体外培养获得了较纯的BMSCs;在乳鼠视网膜细胞条件分化液的环境中,诱导后72h,BMSCs胞体收缩成锥形或球形,细胞突起变细、变长,呈神经细胞的典型形态;免疫组化结果显示,部分细胞呈神经元特异性烯醇化酶(NSE)、巢蛋白(nestin)和Thy1.1阳性反应。结论乳鼠视网膜细胞条件分化液可诱导BMSCs分化成视网膜神经节样细胞。     

Ngn3-Positive Cells Arise from Pancreatic Duct Cells

The production of pancreatic β cells is the most challenging step for curing diabetes using next-generation treatments. Adult pancreatic endocrine cells are thought to be maintained by the self-duplication of differentiated cells, and pancreatic endocrine neogenesis can only be observed when the tissue is severely damaged. Experimentally, this can be performed using a method named partial duct ligation (PDL). As the success rate of PDL surgery is low because of difficulties in identifying the pancreatic duct, we previously proposed a method for fluorescently labeling the duct in live animals. Using this method, we performed PDL on neurogenin3 (Ngn3)-GFP transgenic mice to determine the origin of endocrine precursor cells and evaluate their potential to differentiate into multiple cell types. Ngn3-activated cells, which were marked with GFP, appeared after PDL operation. Because some GFP-positive cells were aligned proximally to the duct, we hypothesized that Ngn3-positive cells arise from the pancreatic duct. Therefore, we next developed an in vitro pancreatic duct culture system using Ngn3-GFP mice and examined whether Ngn3-positive cells emerge from this duct. We observed GFP expressions in ductal organoid cultures. GFP expressions were correlated with Ngn3 expressions and endocrine cell lineage markers. Interestingly, tuft cell markers were also correlated with GFP expressions. Our results demonstrate that in adult mice, Ngn3-positive endocrine precursor cells arise from the pancreatic ducts both in vivo and in vitro experiments indicating that the pancreatic duct could be a potential donor for therapeutic use.     

Adult Renal Stem/Progenitor Cells Can Modulate T Regulatory Cells and Double Negative T Cells

Adult Renal Stem/Progenitor Cells (ARPCs) have been recently identified in the human kidney and several studies show their active role in kidney repair processes during acute or chronic injury. However, little is known about their immunomodulatory properties and their capacity to regulate specific T cell subpopulations. We co-cultured ARPCs activated by triggering Toll-Like Receptor 2 (TLR2) with human peripheral blood mononuclear cells for 5 days and 15 days and studied their immunomodulatory capacity on T cell subpopulations. We found that activated-ARPCs were able to decrease T cell proliferation but did not affect CD8⁺ and CD4⁺ T cells. Instead, Tregs and CD3⁺ CD4^- CD8^- double-negative (DN) T cells decreased after 5 days and increased after 15 days of co-culture. In addition, we found that PAI1, MCP1, GM-CSF, and CXCL1 were significantly expressed by TLR2-activated ARPCs alone and were up-regulated in T cells co-cultured with activated ARPCs. The exogenous cocktail of cytokines was able to reproduce the immunomodulatory effects of the co-culture with activated ARPCs. These data showed that ARPCs can regulate immune response by inducing Tregs and DN T cells cell modulation, which are involved in the balance between immune tolerance and autoimmunity.