Antimicrobial resistance and production of toxins in Escherichia coli strains from wild ruminants and the alpine marmot

Escherichia coli strains isolated from 81 fecal samples from red deer (Cervus elaphus), roe deer (Capreoulus capreoulus), chamois (Rupicapra rupicapra) and alpine marmot (Marmota marmota) living in the Stelvio National Park, Italy, were examined for antimicrobial resistance and production of toxic factors. Direct plating of specimens on media containing antimicrobial drugs allowed us to isolate resistant strains of E. coli from 10 of 59 (17%) specimens examined by this technique. Nine of 31 specimens from red deer (29%) contained resistant strains. Different animals were likely colonized by the same resistant strain of E. coli. Conjugative R plasmids were found in four strains isolated from the marmot, roe deer and chamois. A strain from red deer produced heat-stable enterotoxin and another strain produced both hemolysin and cytotoxic necrotizing factor. A marmot isolate produced hemolysin alone. No strains were found to produce heat-labile enterotoxin or verotoxins.     

New technic for purification of lymphocytes for HLA typing

Many of the difficulties encountered in HLA typing derive from the separation of relatively pure cell suspensions for the lymphocytotoxicity test. We have used Immunomagnetic Beads (I.B.) coated with anti-CD8 or CD2 MAb for Class I positive cell selection and I.B. coated with anti-DR for Class II. With this method, compared to traditional techniques, we obtained high purity and viability of cell populations (about 90%), directly from whole blood in 25 minutes. Shorter incubation with antisera and complement was needed and the global time of tissue typing results decreased (150 min. versus 6 hours). There was no single discrepancy in the tissue typing results between I.B. and traditional methods.     

Quantitative histochemical studies of the effect of levamisole on splenic T-cells in thymectomized Bufo bufo larvae

Summary The ability of levamisole (LVS) to correct the effect of thymectomy on splenic T-cell population in Bufo bufo larvae was tested. Using the nonspecific acid -naphthyl acetate esterase (ANAE) technique, the T-lymphocytes displayed a characteristic reddish brown spot (T-pattern). The total number of white cells per spleen and the number of T-pattern cells per 100 splenic white cells were determined. In addition, differential counts of the T-patterns were made on the basis of the size of their spots.Thymectomized larvae in comparison to sham-operated larvae posessed a lower total number of splenic white cells with a similar proportion of T-pattern cells, but a lower proportion of cells with a large T-pattern. After seven days of LVS treatment, the thymectomized larvae showed an increased total number of splenic white cells and an increased proportion of cells with a large T-pattern, both data falling within normal limits. The effect of LVS appeared marked in thymectomized larvae, but was slight or absent in sham-operated larvae. Differential counts of the large T-pattern cells, based on the size of ANAE reaction product, showed the capacity of LVS to stimulate T-cell maturation. It was concluded that LVS induced proliferation and differentiation of splenic T-cells and that the different sizes of T-pattern reaction represent different maturational stages of T-cells.     

The Ca-MOv18 molecule, a cell-surface marker of human ovarian carcinomas, is anchored to the cell membrane by phosphatidylinositol

The structure of the 38 kD cell surface glycoprotein identified by the monoclonal antibody MOv18 and specifically expressed by human ovarian carcinomas has been investigated at a molecular level. The ovarian carcinoma cell line IGROV-1, which expresses high levels of Ca-MOv18, was treated with the phosphatidylinositol-specific phospholipase C from B. thuringiensis. The phospholipase C specifically released most of the Ca-MOv18 molecules as shown by flow cytometric analysis of the treated cells and by radioimmunometric assays of the corresponding supernatants. Consistent with the known structure of other phosphatidylinositol-linked molecules, Ca-MOv18 was biosynthetically labeled by [3H]ethanolamine and the labeled molecules were immunoprecipitated from the supernatant fo the phospholipase C treated cells. Evidence that Ca-MOv18 is anchored to the cell membrane via phosphatidylinositol may prove to be relevant in current investigations regarding the biological and clinical significance of this tumor marker.     

Molecular characterization of Tunga trimamillata and T. penetrans (Insecta, Siphonaptera, Tungidae): taxonomy and genetic variability

A new species of the genus Tungo, T. trimamillata has recently been described on the basis of several morphological traits. To explore the taxonomic status of this flea with respect to T. penetrans, we undertook a molecular analysis of cytochrome oxydase II and 16S rDNA mitochondrial genes and of the internal transcribed spacer 2 nuclear marker on samples of both species. Maximum Parsimony evaluations of the three data set indicate a differentiation compatible with a specific rank between the two fleas with very high levels of divergence. Both mitochondrial and nuclear data are in line with a recent bottleneck in the Malagasy population of T. penetrans, possibly due to the recent colonisation of Africa via human transportation. Further, significantly lower mitochondrial variability in the Ecuadorian populations of T. penetrans with respect to the T. trimamillata ones is also evidenced.