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41.
针对生物破乳剂产生菌筛选难的问题, 采用显色法、溶血细胞测试法、表面张力测定法和排油圈法从6种不同菌源对生物破乳菌产生菌进行了筛选。通过试验筛选得到了17株生物破乳剂产生菌, 其中24h内破乳率高于70%的破乳菌有5株; 油田含油污泥、采油废水生物处理污泥和污水处理厂剩余污泥是筛选破乳菌的较好的菌源; 显色法、溶血圈法存在检测范围的局限性; 表面张力测定法和排油圈法是最为简易和准确的生物表面活性剂产生菌的筛选方法, 采用模型乳状液对生物破乳剂产生菌进行筛选最为直接和准确, 但工作量大、所需时间长, 因此在筛选高效破乳菌时, 建议采用表面张力、排油圈法进行初筛, 而后通过模型乳状液破乳进行验证。 相似文献
42.
Jiang Zhou Yunhai Ma Lili Ren Jin Tong Ziqin Liu Liang Xie 《Carbohydrate polymers》2009,76(4):632-638
Surface crosslinked thermoplastic starch (TPS)/PVA blend films were prepared by applying ultra violet (UV) irradiation. Sodium benzoate was used as photosensitizer and induced onto film surface layer by soaking the TPS/PVA films in the photosensitizer aqueous solution. The effects of concentration of photosensitizer aqueous solution, soaking time and UV irradiation dose on the surface photocrosslinking reaction were investigated. Physical properties, such as water contact angle, moisture absorption, swelling degree and solubility in water as well as mechanical properties of the films were measured to characterize the influence of the surface photocrosslinking modification. The obtained results showed that the surface modification considerably reduced the surface hydrophilic character of the TPS/PVA films, enhanced the film’s water resistance and also increased tensile strength and Young’s modulus but decreased elongation at break of the films. 相似文献
43.
为了提高生物表面活性剂的表面活性,通过单因素及正交试验对已筛选的产生物表面活性剂芽孢杆菌的培养基及培养条件进行了优化,优化后的培养基成分为可溶性淀粉20 g/L,氯化铵2 g/L,KH2PO46 g/L,K2HPO42 g/L,MgSO4.7H2O 0.3 g/L,NaCl 2 g/L,CaCl20.08 g/L,EDTA 0.4 g/L。培养条件为4%接种量,种龄16 h,初始pH7,培养温度37℃,摇床转速160 r/min,发酵48 h。优化发酵条件后,发酵液表面张力由初始67.5 mN/m降低至24.8 mN/m,生物表面活性剂产量达到1.08 g/L。 相似文献
44.
海湾扇贝血细胞的表面结构及超微结构 总被引:7,自引:0,他引:7
通过光镜、扫描电镜和透射电镜的观察对海湾扇贝血细胞的形态、表面结构及超微结构进行了研究。根据细胞的大小、形态结构可将血细胞分成四种类型:Ⅰ型小透明细胞,大小约(2·38±0·08)μm,约占比例30%-35%;Ⅰ型大透明细胞,大小约(4·41±0·33)μm,约占比例15%-25%;Ⅱ型小颗粒细胞,大小约(4·15±0·26)μm,约占比例20%-25%;Ⅱ型大颗粒细胞,大小约(8·26±0·52)μm,约占比例25%-30%。血细胞在血淋巴中的平均密度为(3·75±0·65)×107cell/ml。其中Ⅰ型透明细胞占55·3%,Ⅱ型颗粒细胞占44·7%。表面结构观察结果显示有5种形态:圆形血细胞,梨形或梭形血细胞,松果形血细胞,阿米巴样细胞,大型细胞,表面结构与功能密切相关。透射电镜观察结果表明血细胞主要归属于两大类型:Ⅰ型透明细胞和Ⅱ型颗粒细胞。超微结构显示颗粒细胞的细胞质颗粒可区分成三种类型:Ⅰ型高电子密度颗粒,Ⅱ型低电子密度颗粒和Ⅲ型中等电子密度颗粒,并推测Ⅰ型高电子密度颗粒是细胞吞噬的异物(微生物等)或细胞内的废物(沉积颗粒,衰老的胞器或碎片);Ⅱ型低电子密度颗粒是溶酶体类的胞内分泌颗粒,来源于高尔基复合体或内质网;Ⅲ型中等电子密度颗粒可能是次级溶酶体,由Ⅰ型颗粒向Ⅱ型颗粒融合并注入裂解酶类而形成[动物学报51(3):486-494,2005]。 相似文献
45.
Min Lin Ying Zhao ShuQi Wang Ming Liu ZhenFeng Duan YongMei Chen Fei Li Feng Xu TianJian Lu 《Biotechnology advances》2012
Lanthanide (Ln)-doped upconversion nanoparticles (UCNPs) with appropriate surface modification can be used for a wide range of biomedical applications such as bio-detection, cancer therapy, bio-labeling, fluorescence imaging, magnetic resonance imaging and drug delivery. The upconversion phenomenon exhibited by Ln-doped UCNPs renders them tremendous advantages in biological applications over other types of fluorescent materials (e.g., organic dyes, fluorescent proteins, gold nanoparticles, quantum dots, and luminescent transition metal complexes) for: (i) enhanced tissue penetration depths achieved by near-infrared (NIR) excitation; (ii) improved stability against photobleaching, photoblinking and photochemical degradation; (iii) non-photodamaging to DNA/RNA due to lower excitation light energy; (iv) lower cytotoxicity; and (v) higher detection sensitivity. Ln-doped UCNPs are therefore attracting increasing attentions in recent years. In this review, we present recent advances in the synthesis of Ln-doped UCNPs and their surface modification, as well as their emerging applications in biomedicine. The future prospects of Ln-doped UCNPs for biomedical applications are also discussed. 相似文献
46.
Naturally spawned eggs of the hydrozoan jellyfish Cladonema pacificum are arrested at G1-like pronuclear stage until fertilization. Fertilized eggs of Cladonema undergo a series of post-fertilization events, including loss of sperm-attracting ability, expression of adhesive materials on the egg surface, and initiation of cell cycle leading to DNA synthesis and cleavage. Here, we investigate whether these events are regulated by changes in intracellular Ca2+ concentration and mitogen-activated protein kinase (MAP kinase) activity in Cladonema eggs. We found that MAP kinase is maintained in the phosphorylated form in unfertilized eggs. Initiation of sperm-induced Ca2+ increase, which is the first sign of fertilization, was immediately followed by MAP kinase dephosphorylation within a few minutes of fertilization. The fertilized eggs typically stopped sperm attraction by an additional 5 min and became sticky around this time. They further underwent cytokinesis yielding 2-cell embryos at approximately 1 h post-fertilization, which was preceded by DNA synthesis evidenced by BrdU incorporation into the nuclei. Injection of inositol 1,4,5-trisphosphate (IP3) into unfertilized eggs, which produced a Ca2+ increase similar to that seen at fertilization, triggered MAP kinase dephosphorylation and the above post-fertilization events without insemination. Conversely, injection of BAPTA/Ca2+ into fertilized eggs at approximately 10 s after the initiation of Ca2+ increase immediately lowered the elevating Ca2+ level and inhibited the subsequent post-fertilization events. Treatment with U0126, an inhibitor of MAP kinase kinase (MEK), triggered the post-fertilization events in unfertilized eggs, where MAP kinase dephosphorylation but not Ca2+ increase was generated. Conversely, preinjection of the glutathione S-transferase (GST) fusion protein of MAP kinase kinase kinase (Mos), which maintained the phosphorylated state of MAP kinase, blocked the post-fertilization events in fertilized eggs without preventing a Ca2+ increase. These results strongly suggest that all of the three post-fertilization events, cessation of sperm attraction, expression of surface adhesion, and progression of cell cycle, lie downstream of MAP kinase dephosphorylation that is triggered by a Ca2+ increase. 相似文献
47.
Outer membrane proteins of pathogenic spirochetes 总被引:10,自引:0,他引:10
48.
Protein purification development is the bottleneck of recombinant protein production therefore there is a need to shorten process development and monitoring. Surface enhanced laser desorption/ionization-mass spectrometry (SELDI-MS) was evaluated to optimize the expression and to develop the purification of a recombinant mouse protein: a transmembrane adaptor involved in T cell receptor signaling named "linker for activation of T cells" (LAT). The protein was expressed as a soluble form (S-LAT) in three strains of Escherichia coli: BL21 (DE3), Rosetta (DE3), and BL21 (DE3) pLys S. The expression of S-LAT was monitored on immobilized metal affinity chromatography (IMAC) ProteinChip arrays. The highest level of expression was found in Rosetta (DE3) with a C-terminal construct after induction at 37 degrees C. The purification scheme was elucidated using SELDI-MS: S-LAT was efficiently captured on an IMAC ProteinChip array saturated with nickel ions (Ni(2+)) and then fractionated on a Q ProteinChip array. These conditions were directly transferred to IMAC-Ni(2+) HyperCel and Q Ceramic HyperD F chromatography sorbents. After these two purification steps, S-LAT was estimated to be more than 80% pure, confirming a very good match between array and sorbent. Finally, a peptide mapping was performed on a hydrophobic array after in gel trypsin digest, verifying that the purified protein was the mouse LAT. This is the first report of a protocol for the production and purification of S-LAT. The selection of the best expression and purification strategy along with the identification were enabled in 5 days with less than 5 mL of soluble fraction of crude culture samples. 相似文献
49.
基于表面等离子共振的新型生物传感技术及其在生命科学中的应用 总被引:5,自引:0,他引:5
生物分子的活性功能是通过分子之间的相互作用来体现的,了解这种相互作用的过程对于生命科学领域的研究及揭示生命发生发展的基本机制具有重要的意义。基于表面等离子共振(surface plasmon resonance,SPR)的新型生物传感技术——BIAcore(biomolecular interaction analysis)是研究生物分子相互作用的理想工具。它可以实时跟踪检测生物分子间结合、解离的整个过程,已被广泛应用于蛋白质组学、信号转导、新药开发、遗传学分析和食品检测等领域,并且显示出广阔的应用前景。 相似文献
50.