Transition of the R factor NR1 and Proteus mirabilis: level of drug resistance of nontransitioned and transitioned cells.

When Proteus mirabilis harboring the R factor NR1 is cultured in Penassay broth containing 100 mug of chloramphenicol (CM) per ml, there is an amplification in the number of copies of the r-determinants per cell. Under these conditions, R factors harboring multiple tandem sequences of r-determinants are formed. Autonomous poly-f-determinants consisting of multiple copies of r-determinants are also formed. This phenomenon has been referred to as the "transition". Transitioned cells have considerably higher levels of resistance to CM and streptomycin (SM), but not to tetracycline (TC), than do nontransitioned cells and grow more rapidly in medium containing either CM or SM. There is essentially no difference in growth rates between transitioned and nontransitioned cells in drug-free medium. The higher level of resistance of transitioned cells to SM has made it possible to investigate the mechanism of the transition. Using replica plating, it has been possible to isolate spontaneously occurring transitioned cells from a nontransitioned population which appear to outgrow the nontransitioned cells during growth in medium containing 100 mug of CM per ml. If transiitoned cells are subsequently cultured in drug-free medium, the cells return gradually to the nontransitioned state, which has been referred to as the "back-transition was monitored by examining the level of resisitance of the cells to SM. In both situations the cell populations were found to be heterogeneous, consisting of a mixture of nontransitioned and transitioned cells. Under the conditions of our experiments, the transition appeared to be due to the more rapid growth of a minor fraction of spontaneously occurring transitioned cells which outgrew the remainder of cells in the population. To obtain the transition, the drug resistance gene must reside on the r-determinants component of the R factor. The transition did not take place when the cells were cultured in medium containing high concentrations of TC. This indicates that the TC resistance genes reside on the resistance transfer factor component of the R factor, which is in agreement with physical studies on R factor deoxyribonucleic acid.     

Reduction by phytate-reduced soybean beta-conglycinin of plasma triglyceride level of young and adult rats.

This study examined the effects of soybean beta-conglycinin, from which phytate was mostly removed, on the plasma lipids in young and adult rats. Male Wistar young (6 week-old) and adult (21 week-old) rats were fed high cholesterol diets containing 20% casein, soy protein isolate (SPI), or soybean beta-conglycinin for 10 days. In young rats, although the food intake of the beta-conglycinin group was higher than those of the casein and SPI groups, the weight gain was significantly lower than those of the other groups. However, in adult rats, the weight gain was not different among the groups. In young and adult rats, relative liver weights of SPI and beta-conglycinin groups were significantly lower than that of the casein group, and the degree of the reduction was more marked in the beta-conglycinin group than in the SPI group. In young rats, the plasma triglyceride level was significantly lower in the SPI and beta-conglycinin groups than that in the casein group. In addition, the plasma triglyceride level of the beta-conglycinin group was significantly lower than that of the SPI group. Plasma total cholesterol levels of the SPI and beta-conglycinin groups were significantly lower than that of the casein group. However, there was little difference in the lowering effect between SPI and beta-conglycinin. These results indicate that soybean beta-conglycinin may have lowering functions not only on plasma total cholesterol level, but also on plasma triglyceride level.     

Immunization of A4galt-deficient mice with glycosphingolipids from renal cell cancers resulted in the generation of anti-sulfoglycolipid monoclonal antibodies

In this study, we immunized Gb3/CD77 synthase gene (A4galt) knockout (KO) mice with glycosphingolipids (GSLs) extracted from 3 renal cell cancer (RCC) cell lines to raise monoclonal antibodies (mAbs) reactive with globo-series GSLs specifically expressed in RCCs. Although a number of mAbs reactive with globo-series GSLs were generated, they reacted with both RCC cell lines and normal kidney cells. When we analyzed recognized antigens by mAbs that were specifically reactive with RCC, but not with normal kidney cells at least on the cell surface, many of them turned out to be reactive with sulfoglycolipids. Eight out of 11 RCC-specific mAbs were reactive with SM2 alone, and the other 3 mAbs were more broadly reactive with sulfated glycolipids, i.e. SM3 and SM4 as well as SM2. In the immunohistochemistry, these anti-sulfoglycolipids mAbs showed RCC-specific reaction, with no or minimal reaction with adjacent normal tissues. Thus, immunization of A4galt KO mice with RCC-derived GSLs resulted in the generation of anti sulfated GSL mAbs, and these mAbs may be applicable for the therapeutics for RCC patients.     

Fused heterocyclic amido compounds as anti-hepatitis C virus agents

We identified a fused heteroaromatic amido structure based on the phenanthridine skeleton as a superior scaffold for candidate drugs with potent anti-HCV activity. Among the compounds synthesized, a phenanthridine analogue with a 1,3-dioxolyl group (24) possessed the most potent anti-HCV activity (EC(50) value: 50 nM), with acceptable cytotoxicity. The structural development and structure-activity relationships of these compounds are described.     

Changes in polyamine-oxidizing capacity of peroxisomes under various physiological conditions in rats

Rat liver peroxisomal polyamine oxidase activity was determined under various physiological conditions by using the peroxidase method with phenol and 4-aminoantipyrine. N1-Acetylpolyamines such as N1-acetylspermine and N1-acetylspermidine were better substrates than the free polyamines. The polyamine oxidase activity in rat peroxisomes increased significantly when cell proliferation was high. The activity began to appear in fetal liver at the 16th approximately 18th day of pregnancy and peaked in neonatal liver on the first day (approx. 1.7-times higher than in adult liver). In regenerating rat liver, only polyamine oxidase activity among the peroxisomal enzymes tested was increased considerably 12 h after partial hepatectomy (approx. 2.8-fold over the control liver). Finally, the enzyme activity was significantly increased by administration of clofibrate, a peroxisome proliferator, which also causes hepatomegaly. In all cases, the increase in polyamine oxidase activity was not more than 3-fold. Since the level of polyamine oxidase activity in the normal liver is more than adequate in relation to the level of the substrates, the slight but significant increase under conditions of cell proliferation may have a role in modulating levels of polyamines in the proliferating liver tissue.     

Allosteric effects of four stereoisomers of a fused indole ring system with 3H-N-methylscopolamine and acetylcholine at M1-M4 muscarinic receptors

We previously demonstrated that brucine and some analogues allosterically enhance the affinity of ACh at muscarinic receptor subtypes M1, M3 or M4. Here we describe allosteric effects at human M1-M4 receptors of four stereoisomers of a pentacyclic structure containing features of the ring structure of brucine. All compounds inhibited 3H-NMS dissociation almost completely at all subtypes with slopes of 1, with similar affinity values at the 3H-NMS-occupied receptor to those estimated from equilibrium assays, consistent with the ternary complex allosteric model. Compound 1a showed positive cooperativity with H-NMS and small negative or neutral cooperativity with ACh at all subtypes. Its stereoisomer, 1b, showed strong negative cooperativity with both 3H-NMS and ACh across the subtypes. Compound 2a was positive with 3H-NMS at M2 and M4 receptors, neutral at M3 and negative at M1 receptors; it was negatively cooperative with ACh at all subtypes. Its stereoisomer, 2b, was neutral with 3H-NMS at M1 receptors and positive at the other subtypes; 2b was negatively cooperative with ACh at M1, M3 and M4 receptors but showed 3-fold positive cooperativity with ACh at M2 receptors. This latter result was confirmed with further 3H-NMS and 3H-ACh radioligand binding assays and with functional assays of ACh-stimulated 35S-GTPgammaS binding. These results provide the first well characterised instance of a positive enhancer of ACh at M2 receptors, and illustrate the difficulty of predicting such an effect.     

Anthocyanins from red flowers of Camellia reticulata LINDL

Ten anthocyanins, cyanidin 3-sambubioside, 3-glucoside and their acylated derivatives, cyanidin 3-lathyroside and cyanidin 3-galactoside, were isolated from red flowers of Camellia reticulata. Their structures were determined on the basis of spectroscopic analyses, and the chemotaxonomic distribution of the accumulated anthocyanins in the petals of wild Camellia reticulata and C. pitardii var. yunnanica is discussed.     

Engagement of overexpressed Her2 with GEP100 induces autonomous invasive activities and provides a biomarker for metastases of lung adenocarcinoma

Overexpression of Her2/ErbB2/Neu in cancer is often correlated with recurrent distant metastasis, although the mechanism still remains largely elusive. We have previously shown that EGFR, when tyrosine-phosphorylated, binds to GEP100/BRAG2 to activate Arf6, which induces cancer invasion and metastasis. We now show that overexpressed Her2 in lung adenocarcinoma cells also employs GEP100. Like EGFR-GEP100 binding, this association is primarily mediated by the pleckstrin homology (PH) domain of GEP100 and Tyr1139/Tyr1196 of Her2. Tyr1139/Tyr1196 are autonomously phosphorylated, when Her2 is overexpressed. Accordingly, invasive activities mediated by the Her2-GEP100 pathway are not dependent on external factors. Blocking Her2-GEP100 binding, as well as its signaling pathway all inhibit cancer invasive activities. Moreover, our clinical study indicates that co-overexpression of Her2 with GEP100 in primary lung adenocarcinomas of patients is correlated with the presence of their node-metastasis with a statistical significance. Since the GEP100 PH domain interacts with both Her2 and EGFR, targeting this domain may provide novel cancer therapeutics.