扁藻多糖的性质及结构特征的研究

利用不同浓度范围的乙醇从培养至平衡期后的扁藻细胞内沉淀分离出不同组分的扁藻多糖级分,对其理化性质和结构特征进行了相应的测定和对比分析。结果表明,经过凝胶层析分离后,乙醇浓度在0%~50%范围时沉淀的扁藻多糖与乙醇浓度为50%~75%范围时沉淀的扁藻多糖相比,前者分子量大、糖含量高、其结合的蛋白质也多,但前者的溶解度和粘度小于后者。两个级分的扁藻多糖的官能团相似,均含有硫酸基和氨基,但其含量不同。所得结果为深入研究扁藻多糖的结构及其实际应用提供了实验依据。     

亚心形扁藻多糖的提取分离纯化及组成研究

以实验室培养的亚心型扁藻为原料,热水提取扁藻多糖。多糖经加热除蛋白、乙醇分级、Sephadex G-50柱层析等一系列纯化步骤后,得到一扁藻多糖(简称PPSc-1)。PPSc-1经醋酸纤维素薄膜电泳和SephadexG-100柱层析的纯度鉴定,组分均一。将多糖PPSc-1用三氟乙酸全水解,然后进行HPAEC-PAD分析,结果表明组成该多糖的单糖为D-半乳糖、D-2-氨基葡萄糖、D-阿拉伯糖、D-鼠李糖和3种未知单糖。各种已知单糖的摩尔比是D-半乳糖∶D-2-氨基葡萄糖∶D-阿拉伯糖∶D-鼠李糖=59.64∶40.9∶18∶1。     

Onconase对B16黑色素瘤细胞的体内外生长抑制作用

Onconase(Onc)是一种从林蛙(Rana pipiens)卵细胞内提取的核酸酶,实验证实其在体外和体内对多种肿瘤细胞都具有显著的杀伤效果。在大肠杆菌中表达纯化的重组Onc和天然提取蛋白质具有相似的活性,通过测定该蛋白质对黑色素瘤B16细胞的IC50和建立荷瘤小鼠模型探讨了Onc体内外的抗肿瘤效果。实验结果表明:B16细胞在体外对Onc敏感性较K562细胞低,其IC50为6.37μmol/L;但体内每次每只小鼠给予5mg/kg Onc也可显著地抑制B16细胞的生长,延长小鼠的生存时间。实验提供了一种简化高效获得具有天然活性Onc的方法,同时通过Onc对低敏感性肿瘤黑色素瘤细胞的杀伤研究,丰富了对Onc抗肿瘤作用的认识,为治疗黑色素瘤提供了线索。     

小分子Rhizobium sp. N613胞外多糖的制备及其抗肿瘤活性

采用微波辐照氧化技术,降解大分子Rhizobium sp.N613胞外多糖(REPS)为小分子多糖(LREPS),以改善其理化及抗肿瘤活性,提高应用价值和拓展应用范围。通过正交试验考察了底物浓度、H2O2浓度、微波辐照强度和辐照时间对降解产物分子量的影响并获得一系列LREPS产物。选取4组分子量段(10以下、10、20和30 kD左右)的LREPS代表性样品进行小鼠体内S180抑瘤效果检测,其中分子量段为10.352 kD的LREPS效果最佳,抑瘤率高达52.8%,确定为LREPS的最适分子量段。其制备工艺条件为:REPS浓度为2 g/L、H2O2浓度为6%、微波辐照强度为375 W、微波辐照时间为2 min;理化分析结果表明,LREPS的红外图谱与REPS相似,仍为β-D-吡喃葡聚糖。其溶解度由原多糖的8.00 g/L增至15.73 g/L,特性粘数由原多糖的527.64 mL/g降至351.67 mL/g。建立了LREPS制备工艺并获取了相关理化及抗肿瘤技术参数,为该多糖制剂的生产应用奠定一定基础。     

功能性低分子量岩藻多糖的研究进展

低分子量岩藻多糖来源于褐藻,是一类含有硫酸基团的多糖,具有多种生物学功能,如抗凝血、抗病毒、抗血栓、抗肿瘤等功能,因此可被广泛地应用于医药、食品等领域。着重介绍了低分子量岩藻多糖的制备及其生物学功能的研究进展。     

羧甲基茯苓多糖的制备及体内抗肿瘤作用的实验研究

目的 :探讨羧甲基茯苓多糖的制备方法及体内抗肿瘤作用。方法 :选择性氧化茯苓菌发酵液得羧甲基茯苓多糖 ,检测三个剂量的羧甲基茯苓多糖 (2 mg/ ml、4mg/ ml、6mg/ ml)对 H2 2 荷瘤小鼠淋巴细胞转化率和 NK细胞杀伤活性以及血清中 TNF-α含量的影响。结果 :羧甲基茯苓多糖三个剂量组均可提高荷瘤小鼠的淋巴细胞转化率和 NK细胞杀伤活性 ,与生理盐水组相比差异有显著性 (P<0 .0 5) ,中剂量组抗肿瘤的效果显著 ,与其他两组相比差异有显著性 (P<0 .0 5) ;羧甲基茯苓多糖三个剂量组均可提高荷瘤小鼠血清中 TNF-α的含量 ,与生理盐水组相比差异有显著性 (P<0 .0 5) ,但三个剂量组之间比较差异无显著性 (P<0 .0 5)。结论 :羧甲基茯苓多糖可改善荷瘤小鼠的免疫功能 ,具有抗肿瘤作用 ,且功效与作用剂量间有一定的关系 ,在最佳剂量时活性最高     

火木层孔菌发酵菌粉及其组分对小鼠移植性肝癌H22的体内生长作用

采用肝癌H22荷瘤小鼠的肿瘤模型,对火木层孔菌(桑黄)Phellinus igniarius发酵菌粉及其各提取物组分的体内抗肿瘤活性进行评价。结果表明,火木层孔菌发酵菌粉及其各提取物组分对荷瘤小鼠肝癌H22都具有一定的抗肿瘤作用并能延长荷瘤小鼠生存期,其中,火木层孔菌发酵菌粉(1,000mg/kg/d)及其组分I(I多糖组分)(360mg/kg/d)具有较为显著的抗肿瘤作用,抑瘤率分别为33.5%和40.3%。组织病理学研究结果表明在菌粉及其多糖组分作用后,肿瘤细胞坏死细胞明显增多,免疫组化检测表明火木层孔菌发酵菌粉及其多糖组分能明显的降低瘤组织中Bcl-2基因蛋白的表达,提高小鼠瘤组织中的Bax基因蛋白的表达。火木层孔菌发酵菌粉及其多糖组分具有较好的体内抗肿瘤活性。     

核甙类抗生素产生菌的筛选及其活性组分研究

从成都郊区土壤中筛选出一株能产生抗生素的放线菌 ,经过形态及培养特征观察、生理生化特性试验、细胞壁化学组成分析 ,确定其分类学归属为链霉菌属 ( Strep-tomyces)。从产生菌的固体培养物中分离得到活性物质、理化性质研究表明 ,该物质为胞嘧啶核苷衍生物。抗菌和抗肿瘤活性试验结果显示 ,此物质不仅具有抑菌活性 ,而且具有较强的抗肿瘤活性。     

小刺猴头菌多糖的荧光标记及其稳定性

通过体外和小鼠体内试验,验证荧光标记的小刺猴头菌多糖的稳定性和生物体内代谢途径。结果表明:标记后的小刺猴头菌多糖体外稳定性在24 h内良好,小鼠体内代谢途径主要通过消化系统代谢,并在8 h内基本代谢完毕,这一结果为荧光标记真菌多糖的药理活性提供了依据。     

香菇不同发育阶段子实体多糖的理化性质及体外免疫活性研究

香菇多糖是从香菇菌丝体或子实体中提取纯化得到的高分子葡聚糖,作为香菇主要的生物活性物质,具有提高免疫力、抗病毒、抗氧化和抗真菌等生物活性。本研究对幼菇期、菌褶期、采收期、成熟期和开伞期5个不同发育阶段香菇粗多糖含量、理化性质和体外免疫活性进行比较分析。结果表明,其粗多糖含量、理化性质和体外免疫活性具有明显差异。粗多糖得率呈现先增加后降低的趋势,菌褶期得率最高;粗多糖含量也呈现先增加后降低的趋势,成熟期含量最高;多糖的分子量因发育期不同而有较大差异,发育后期所得粗多糖分子量千万级以上组分的比例增加,分子量百万级和十万级的多糖组分比例降低;不同发育阶段香菇子实体多糖的单糖组成均包含果糖、半乳糖、葡萄糖和甘露糖4种单糖,且都以葡萄糖为主;5个阶段的多糖组分均有较好的体外免疫活性,其中幼菇期粗多糖在浓度500μg/mL时表现出最高的体外免疫活性。本研究探讨了香菇不同发育阶段子实体多糖的理化性质及体外免疫活性,为香菇采收期的确定及香菇多糖的制备与利用提供理论依据。     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.