Enhanced susceptibility of target KMT-17 cells to activated macrophages by treatment with the antitumor agent bleomycin

Summary We observed that after KMT-17 cells had been treated with bleomycin (BLM), even with a dose as high as 160 g/ml, they were still able to form colonies in soft agar. We then studied the susceptibility of KMT-17 cells treated with BLM to activated macrophages. During a colony inhibition assay, BLM-treated KMT-17 cells were found to be much more susceptile to activated macrophages than nontreated KMT-17 cells, moreover, a tumor neutralizing assay showed that the growth of BLM-treated KMT-17 cells was also significantly inhibited by activated macrophages as compared with nontreated KMT-17 cells. Macrophages activated by both BLM and the Nocardia rubra cell wall skeleton were able to mediate such tumor inhibition activity in BLM-treated KMT-17 cells. Activated macrophages did not seem to have strong antitumor activity against nontreated KMT-17 cells in vivo, however, the life span of the rats which were inoculated i. p. with KMT-17 cells was significantly expanded after the tumorbearing rats were given BLM i.p. The data presented here suggest that not only does BLM have a direct tumoricidal effect on KMT-17 cells, it also regulates immunosensitivity of targets to immune effectors. We also discuss the mechanism for enhancing the susceptibility of KMT-17 cells to activated macrophages brought about by treatment with BLM.Supported in part by a Grant-in-Aid for Cancer Research from the Japanese Ministry of Education, Science, and Culture     

甘蔗伤流液中保绿活性物质的分离与初步鉴定

通过化学与物理学方法,从甘蔗(Sugar-cane)伤流液中分离出五种活性因素,对离体叶片有不同程度的保绿效应。依其化学性质判断,应属嘌呤化合物,可能是细胞分裂素物质。     

猪-C反应蛋白的分离纯化及其性质的研究

以猪血清为材料,通过磷酸乙醇胺—琼脂糖亲和层析,Sepharose 4B柱层析和Sephacryl—S300凝胶过滤,获得了猪C—反应蛋白的结晶。猪C—反应蛋白可与肺炎球菌壁C多糖发生特异的沉淀反应,这种结合是依赖钙离子的。EDTA和一些磷脂代谢产物如磷酸胆碱,磷酸乙醇胺等,能抑制猪C—反应蛋白与C多糖的结合。在SDS—聚丙烯酰胺凝胶电泳及梯度聚丙烯酰胺凝胶电泳中,猪C—反应蛋白表现出与人C—反应蛋白相同的行为,亚基是一条分子量为23.5kD的肽链,全分子的表观分子量为150kD。猪C—反应蛋白与兔抗人C—反应的蛋白的抗血清能发生免疫交叉反应。     

点叶绵枣叶片培养及器官分化的研究

点叶绵枣叶外植体培养于MS 6-BA 1 PPm IBA 0.5 ppm培养基中,一月后不定芽仅从近轴面的叶表面产生。组织学的观察表明,不定芽起源于表皮细胞。     

对渤海藻类的新认识

本文阐述了对渤海藻类的新认识。主要指明其为由顶和前间系组成的( 3Ia 或 3I)联合古口的性质,腰凸的数量(2—4个)和分布(2个位腹面,0—2个位背面)及腰褶的次生性质。据此,讨论了该类在多甲藻亚目中的系统位置。除修订本亚科所属的老属、种外,本文还描述了该亚科的2个新种和3个新形态型。并在回顾世界上非海相沟鞭藻的历史、阐述渤海藻亚科在地层中的产出及共生分子的基础上,结合其他地质、古生物证据,探讨了本亚科的古生态及它为多甲藻亚目中一支向淡水环境迁侈的先祖的可能性。     

西双版纳热带季节雨林植物种类多样性的一种研究方法

一、方法1.样地的选择样地分别选取热带干性季节雨林的典型代表——以箭毒木(Antiaris toxicaria)、龙果(Pouteria grandifolia)为标志的群落,以千果榄仁(Terminalia myriocarpa)、番龙眼     

Expression of mammalian liver glycolytic/ gluconeogenic enzymes in Escherichia coli: Recovery of active enzyme is strain and temperature dependent

A number of mammalian enzymes have been expressed in Escherichia coli using the T7 RNA polymerase system, but the production of large amounts of these proteins has been limited by the low percentage of active enzyme that is found in the soluble fraction. In this report the effect of induction temperature was tested on the recovery of four rat liver enzymes, 6-phosphofructo-2-kinase/fructose-2,6- bisphosphatase, fructose-2,6-bisphosphatase, glucokinase, and fructose-1,6-bisphosphatase. We also tested the effect using a host cell strain that contains a plasmid encoding T7 lysozyme, an inhibitor of T7 RNA polymerase. Large amounts of the first three enzymes accumulated in the cells after 4 h of induction at 37 degrees C, but only about 1-2% of the total expressed proteins were recovered in a soluble, active form. When the induction was carried out at 22 degrees C for 48 h with the pLysS strain, 20- to 30-fold higher amounts of the active expressed enzymes were recovered in the soluble fraction, even though the total accumulation and the rate of synthesis of these proteins were reduced. The optimal concentration of isopropyl-1-thio-beta-D-galactopyranoside required for induction was the same at both temperatures. On the other hand, the recovery of active fructose-1,6-bisphosphatase, a heat-stable enzyme, was 66% at 37 degrees C and was essentially unchanged at an induction temperature of 22 degrees C. Lowered induction temperature would appear to be of utility for enhanced recovery of active mammalian enzymes which are insoluble in E. coli cytosol at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adherence Patterns and DNA Probe Types of Escherichia coli Isolated from Diarrheal Patients in China

One hundred and seventy-two strains of Escherichia coli isolated from diarrheal patients in Beijing, P. R. China, were analyzed for plasmid DNA profile, HEp-2 cell adherence ability and reactivity to 10 previously described DNA probes. They had not been recognized as pathogenic E. coli in China. Of the 110 strains tested, 76 (69%) contained one or multiple large plasmids. Of the 71 strains with the large plasmids 64 could adhere to HEp-2 cells. Of the 172 strains, 102 (59.3%) were hybridized with at least one of the 10 probes. Of those, seven strains hybridized with enteroaggregative E. coli (EAggEC) probe. Their serotypes were O128 (two strains), O6 (one strain), and O111 (one strain). Three strains were untypable. Six and three strains were hybridized with enteropathogenic E. coli (EPEC) attaching and effacing genes (eae) or EPEC adherence factor (EAF) probe, respectively. Two non-O157: H7 strains hybridized with enterohemorrhagic E. coli (EHEC) probe. Seventy-two strains (41.9%) hybridized with shiga-like toxin 2 or 1 (SLT2 or SLT1) probes. Among the SLT1 or SLT2 probe-positive strains, 54 hybridized with invasive (INV) plasmid probe developed for identification of enteroinvasive E. coli (EIEC) and Shigella species. The INV and SLT probe-positive strains might represent a new variety of verotoxin-producing E. coli (VTEC).