Major Enteropathogenic Bacteria Isolated from Diarrheal Patients in Bolivia: A Hospital-Based Study

A total of 1,234 fecal samples from diarrhea cases were examined for etiological bacterial agents at medical facilities in La Paz and Sucre, Bolivia. Eighty strains of Shigella spp., 39 strains of Salmonella spp., 29 strains of Vibrio cholerae, and 222 strains of enteropathogenic Escherichia coli (139 EPEC, 55 ETEC, 29 EIEC, and 1 EHEC) were isolated. With regard to the serovars of Shigella, S. flexneri 2a, 3a, and 1b were predominant. In the case of Salmonella, S. enteritidis was the most common, followed by S. typhi, S. poona, and S. paratyphi B. Out of 29 cholera strains, 25 belonged to biovar El Tor, serovar Ogawa while the remaining 4 were serovar Inaba. Among 55 strains of ETEC serotypes, 5 showed ST producers but none showed LT producers. Likewise, among 55 strains of enterohemorrhagic serotypes, only one strain (O157:H7) produced verocytotoxin (VT 2). The results of drug sensitivity tests revealed the predominance of Shigella, EPEC, and ETEC strains resistant to aminobenzil-penicillin (ABPC) and trimethoprim. Since diarrheal patients in Bolivia are treated mainly with ABPC or sulfamethoxazole/trimethoprim (SXT) and rarely with gentamicin, kanamycin, or other drugs, it is possible that ABPC- and SXT-resistant strains will increase and persist in the near future.     

A proline-type fullerene derivative inhibits adipogenesis by preventing PPARγ activation

Obesity and its associated metabolic diseases represent some of the most rapidly expanding health issues worldwide, and, thus, the development of a novel chemical compound to suppress adipogenesis is strongly expected. We herein investigated the effects of water-soluble fullerene derivatives: a bis-malonic acid derivative and three types of proline-type fullerene derivatives, on adipogenesis using NIH-3T3 cells overexpressing PPARγ. One of the proline-type fullerene derivatives (P3) harboring three carboxy groups significantly inhibited lipid accumulation and the expression of adipocyte-specific genes, such as aP2, induced by the PPARγ agonist rosiglitazone. On the other hand, the bis-malonic acid derivative (M) and the 2 other proline-type fullerene derivatives (P1, P2), which have two carboxy groups, had no effect on PPARγ-mediated lipid accumulation or the expression of aP2. P3 fullerene also inhibited lipid accumulation induced by the combined stimulation with 3-isobutyl-1-methylxanthine (IBMX), dexamethasone, and insulin in 3T3-L1 preadipocytes. During the differentiation of 3T3-L1 cells into adipocytes, P3 fullerene did not affect the expression of C/EBPδ, C/EBPβ, or PPARγ, but markedly inhibited that of aP2 mRNA. These results suggest that P3 fullerene exhibits anti-obesity activity by preventing the activation of PPARγ.     

Molecular nature of chromosome 5q loss in colorectal tumors and desmoids from patients with familial adenomatous polyposis

Summary Familial adenomatous polyposis (FAP), which includes familial polyposis coli (FPC) and the Gardner syndrome (GS), is a genetically determined premalignant disease of the colon inherited by a locus (APC) mapping within 5q15–q22. To elucidate the role of 5q loss in FAP tumorigenesis, we analysed 51 colorectal tumors and seven desmoids from 19 cases of FPC and five GS patients, as well as 15 sporadic colon cancers. RFLP analysis revealed a high incidence of allelic deletion in hereditary colon cancers as well as in sporadic colon cancers with a peak at the APC locus. APC loss resulted primarily from interstitial deletion or mitotic recombination. Combined tumor and pedigree analysis in a GS family revealed loss of normal 5q alleles in three tumors, including a desmoid tumor, which suggests the involvement of hemizygosity or homozygosity of the defective APC gene in colon carcinogenesis and, possibly, in extracolonic neoplasms associated with FAP.     

Interleukin 2 increases T lymphocyte membrane mobility before the rise in cytosolic calcium concentration

Using stopped-flow fluorometry with three different fluorescence probes [2-[(1-pyrenyl-butyryl)oxy]stearic acid, chlortetracycline and Quin 2], we have studied initial stage of T lymphocyte activation after interleukin 2 (IL-2) binding to a specific cell-surface receptor. After IL-2 binding to cytotoxic T lymphocyte (IL-2-dependent mouse LC7 and CTLL-2 cells), membrane mobilities of the cells increased first (4.5 +/- 0.3 s-1 for LC7 and 3.8 +/- 0.2 s-1 for CTLL-2), then calcium was released from intracellular stores into the cytoplasm (1.6 +/- 0.1 s-1 for LC7 and 2.1 +/- 0.1 s-1 for CTLL-2), and lastly, calcium was transported from the external medium into the cytoplasm (1.3 +/- 0.1 s-1 for LC7 and 1.5 +/- 0.1 s-1 for CTLL-2). The slowest process, the calcium influx from the external medium, was suppressed in the presence of a calcium channel blocking agent (verapamil). These observations give us a new information to discuss a model in T lymphocyte activation after IL-2 binding to cell-surface receptors.     

Purification and Storage of Ribulose 1,5-bisphosphate Carboxylase from Rice Leaves

Ribulose 1,5-bisphosphate (RuBP) carboxylase was purified fromrice leaves. By using a buffer containing 12.5% (v/v) glycerolthroughout purification, the enzyme was protected from coldlability and was obtained at a high yield (5.5 mg/g fresh wt).The purified enzyme exhibited different rates of CO₂/Mg²⁺-activationby temperature pretreatment/storage. The purified enzyme was stable for at least one year in phosphatebuffer containing 12.5% (v/v) glycerol at 4°C or 50% (v/v)glycerol at –20°C. (Received March 1, 1983; Accepted June 27, 1983)     

Distribution of lipoxygenase and hydroperoxide lyase in the leaves of various plant species

The enzyme activity responsible for volatile C₆-aldehyde formation was accompanied by lipoxygenase and hydroperoxide lyase in the green leaves of 28 plant species tested, but the level of each enzyme's activity varied. Lipoxygenase activity rather than hydroperoxide lyase activity appears to affect the overall C₆-aldehyde formation. There was a positive correlation (r = 0.712) between hydroperoxide lyase activity and the chlorophyll content of the green leaves; no correlation was found between lipoxygenase activity and chlorophyll content.     

STUDIES ON THE FUNCTION OF INTRACELLULAR RIBONUCLEASES : IV. Some Observations on the Properties of Ribosomes and Polysomes from Rat Liver and Hepatomas

Polysome and ribosome preparations from normal rat liver and from a series of transplantable rat hepatomas of different growth rates were compared. All the hepatomas had a significantly higher percentage of RNA in a polysome preparation than did the normal liver, and the polysome preparations from the tumors, with the exception of the Dunning hepatoma which has a high lipid content, gave a greater yield of RNA and protein per gram of wet tissue than the liver did. Heavier polysomes were considerably less prevalent in the tumors than in the liver, and the tumors contained a larger proportion of monomer and dimer ribosomes than the liver did. Evidence is presented that the increased monomer and dimer ribosome population of the hepatomas studied is not an artifact of preparation, but represents the true intracellular distribution. Ribosomes from normal liver and Morris 5123-D hepatoma were readily dissociated by 20 min'' treatment with 1.0 mM EDTA, but ribosomes from the Dunning, Novikoff ascites, and McCoy MDAB hepatomas were little affected by such treatment. With higher concentrations of EDTA, the ribosomes from the Novikoff ascites and McCoy MDAB hepatomas broke down and did not form specific subunits as did ribosomes from liver and the Morris 5123-D hepatoma but rather gave rise to a variety of small degradation products. This behavior is ascribed to a higher RNase content of the Novikoff and McCoy MDAB hepatomas. Dunning hepatoma ribosomes were resistant to 4 mM EDTA.     

Expression of chimeric receptor composed of immunoglobulin-derived V regions and T-cell receptor-derived C regions

Chimeric genes composed of immunoglobulin (Ig)-derived variable (V) regions and T-cell receptor (TCR)-derived constant (C) regions were constructed. The VL and VH genes showing anti-phosphorylcholine (PC) activity were used in this study. Two pairs of chimeric genes, VL-C beta and VH-C alpha genes, and VL-C alpha and VH-C beta genes, were inserted into an expression vector containing both Ecogpt and neo genes, and transfected into EL4 cells. Cells which express both chimeric receptor molecules were established. The activity of the transformants to the antigen was examined by using stopped-flow fluorometry. An increase in the concentration of cytoplasmic calcium ion was observed after addition of Staphylococcus pneumoniae R36A bacteria grown in the choline-containing medium which express PC molecules, but not after the PC-negative bacteria grown in the ethanolamine-containing medium.     

Analysis of a monoclonal rat antibody directed to the alpha-chain variable region (V alpha 3) of the mouse T cell antigen receptor

Three rat mAb, RR3-15, RR3-16, and RR3-18, were established by fusing spleen cells from a rat immunized with the male Ag-specific cytolytic T cell clone, OH6, to mouse myeloma cells. The mAb was identified by their capacity to focus the cytolytic activity of the OH6 CTL clone on nonspecific target cells via FcR-FcR interaction. That all three mAb recognized the OH6 TCR was confirmed by immunoprecipitation studies in which each antibody precipitated a 90 kDa disulfide-linked heterodimer characteristic of the TCR. Surface immunofluorescence staining of a panel of T cell lines and splenic T cell populations showed that RR3-16 reacted not only to the OH6 T cell clone but also to a minor fraction of normal T cells. This reactivity was found to be due to the expression of a gene in the V alpha 3 family. However, RR3-16 did not react with all T cell lines and clones known to express genes from the V alpha 3 family. cDNA sequences of three independent RR3-16+ T cell hybridomas analyzed by polymerase chain reaction were identical to the previously published V alpha 3 sequence of the CTL clone C9. Thus, the mAb RR3-16 is specific for a single member of the TCR V alpha 3 gene family. Analysis of the expression of RR3-16+ TCR in CD4+ and CD8+ subsets of peripheral T cells demonstrated preferential expression on CD8+ T cells, suggesting regulated expression of this particular TCR V alpha gene.