Distribution of Ty3-gypsy- and Ty1-copia-like DNA sequences in the genus Helianthus and other Asteraceae.

Two repeated DNA sequences, pHaS13 and pHaS211, which revealed similarity to the int gene of Ty3-gypsy retrotransposons and the RNAse-H gene of Ty1-copia retroelements, respectively, were surveyed in Asteraceae species and within the genus Helianthus. Southern analysis of the genome of selected Asteraceae that belong to different tribes showed that pHaS13- and pHaS211-related subfamilies of gypsy- and copia-like retroelements are highly redundant only in Helianthus and, to a lesser extent, in Tithonia, a Helianthus strict relative. However, under low stringency posthybridization washes, bands were observed in almost all the other Asteraceae tested when pHaS13 was used as a probe, and in several species when pHaS211 was hybridized. FISH analysis of pHaS13 or pHaS211 probes was performed in species in which labelling was observed in Southern hybridizations carried out under high stringency conditions (Helianthus annuus, Tithonia rotundifolia, Ageratum spp., Leontopodium spp., Senecio vulgaris for pHaS13, and H. annuus, Tithonia rotundifolia, and S. vulgaris for pHaS211). Scattered labelling was observed over all metaphase chromosomes, indicating a large dispersal of both Ty3-gypsy- and Ty1-copia-like retroelements. However, preferential localization of Ty3-gypsy-like sequences at centromeric chromosome regions was observed in all of the species studies but one, even in species in which pHaS13-related elements are poorly represented. Ty1-copia-like sequences showed preferential localization at the chromosome ends only in H. annuus. To study the evolution of gypsy- and copia-like retrotransposons in Helianthus, cladograms were built based on the Southern blot hybridization patterns of pHaS13 or pHaS211 sequences to DNA digests of several species of this genus. Both cladograms agree in splitting the genomes studied into annuals and perennials. Differences that occurred within the clades of perennial and annual species between gypsy- and copia-like retroelements indicated that these retrotransposons were differentially active during Helianthus speciation, suggesting that the evolution of the 2 retroelement families was, within limits, independent.

Relationship of non-protein thiol pools and accumulated Cd or Hg in the marine macrophyte Posidonia oceanica (L.) Delile.

The accumulation of cadmium or mercury and the effect of these elements on the levels of non-protein thiols in the blades of the marine macrophyte Posidonia oceanica were investigated. A significant accumulation of cadmium or mercury, dependent on metal concentration supplied, was observed in metal-treated blades. In the blades treated either with cadmium or mercury, a significant increase in the levels of non-protein thiols (other than glutathione) and a marked depletion of the reduced glutathione content as a function of the metal, exposure time and metal concentration supplied were found. This investigation provides first experimental report on the relationship between non-protein thiol pools and accumulated cadmium or mercury in P. oceanica.

[Hemolytic-uremic syndrome: association with vero cytotoxin-producing Escherichia coli. An epidemiological and microbiological study on possible animal reservoirs]. / La sindrome emolitica-uremica: associazione con escherichia coli verocitotossina produttori. Indagine epidemiologica e microbiologica sui possibili serbatoi animali.

Vero cytotoxin-producing strains of Escherichia coli (VTEC) appear to be in man associated with a range of clinical symptoms from mild non bloody diarrhoea to haemorrhagic colitis and severe haemolytic uraemic syndrome (HUS). We present two patients affected by HUS who were investigated to determine evidence of infection by VTEC. In one of the patient free fecal cytotoxin active on Vero cells was detected as well as seroconversion of VT-neutralizing antibody titre. Both children were living in the same county town, but all parents denied any animal contact. The source of infection was not identified but one child had eaten ground beef during the period immediately prior to the onset of symptoms. Epidemiological informations are presented and the results of a study on the possible animal reservoir are illustrated. Fecal cultures were performed on 38 stools specimen obtained from non diarrheal beef cattle and pork. One VT- producing Escherichia coli strain was isolated in pork faeces (20 stools sample) whereas two VTEC were found in cattle faeces (18 stool sample).

[Bacteriological findings in a group of students from designated health sector]. / Indagine batteriologica su di un gruppo di scolari di un comitato sanitario di zona.

The results of a pharyngeal swab bacteriological examination carried on all first-year primary schoolchildren in a local health area are presented. Beta-haemolytic streptococci, Staphylococcus aureus coagulase + and Corynebacterium diphteriae percentages are illustrated, together with observations of a prophylactic and curative nature.