The effect of various monovalent, divalent and oligovalent cations on the reaction of triplex formation by GT and AG motif triplex-forming oligonucleotides, designed to bind to biologically relevant polypurine±polypyrimidine sequences occurring in the promoters of the murine Ki-ras and human bcr genes, has been investigated by means of electrophoresis mobility shift assays (EMSA) and DNase I footprinting experiments. We found that in the presence of 10 mm MgCl 2 the triple helices were progressively destabilized by adding increasing amounts of NaCl, from 20 to 140 mm, to the solution. We also observed that, while the total monovalent-ion concentration was constant at 100 mm, the exchange of sodium with potassium, but not lithium, results in a further destabilization of the triple helices, due to self-association equilibria involving the G-rich triplex-forming oligonucleotides. Potassium was found to destabilize triplex DNA even when the triple helices are preformed in the absence of K + . However, footprinting experiments also showed that the inhibitory effect of K + on triplex DNA is partially compensated for by millimolar amounts of divalent transition metal ions such as Mn 2+ and Ni 2+ , which upon coordinating to N7 of guanine are expected to enhance hydrogen-bond formation between the target and the third strand, and to reduce the assembly in quadruple structures of G-rich triplex-forming oligonucleotides. Triplex enhancement in the presence of potassium was also observed, but to a lesser extent, when spermine was added to the reaction mixture. Here, the ion effect on triplex DNA is rationalized in terms of competition among the different valence cations to bind to triplex DNA, and differential cation stabilization of unusual quadruplex structures formed by the triplex-forming oligonucleotides.Keywords: bcr gene; bivalent cations; Ki-ras gene; monovalent cations; purine±purine±pyrimidine triplex.Tracts of polypurine±polypyrimidine [poly(R´Y)] sequences often occur in regulation regions of DNA [1]. In this DNA motif, each purine contains a bidentate acceptor±donor hydrogen-bond system that can be recognized by a third guanine-rich oligonucleotide (ODN), through the formation of G´G´C and A´A´T or T´A´T base triplets. The resulting triple-stranded complex is thermodynamically stable under physiological or near-physiological conditions [2±11]. As triplex-forming ODNs bind to poly(R´Y) targets in a highly sequence-specific manner, they represent an interesting class of DNA ligands that allow a number of applications in biotechnology and pharmacology. Among these, the use of triplex-forming ODNs as artificial transcription repressors has drawn the attention of many researchers [12,13]. This strategy is based on the notion that the interaction of triplex-forming ODNs with critical sequences within promoter regions should interfere with transcription, with the consequence of inhibiting the expression of the target gene, without affecting the overall activity of the cell. This original strategy, called the antigene...

This study was carried out using Ixodes ricinus ticks collected during 2005 and 2006 from the Friuli Venezia Giulia (FVG) region in the northeastern part of Italy and an area along the Slovenian side of the western border of Italy. The results indicate that Rickettsia spp. is widely distributed throughout these areas, with the greatest prevalence in the central part of the FVG region. The prevalence of Rickettsia spp. was 4.5% during 2005 and 6.1% during 2006. By sequencing the 16S rRNA gene, we show for the first time the presence of Rickettsia helvetica in I. ricinus ticks in the FVG region and the presence of R. monacensis in ticks in both areas. Furthermore, we detected a sequence with a high homology with that of R. limoniae in a tick obtained from the alpine zone.

The prevalence of antibodies to Rickettsiae and other tick-borne microrganisms in the sera of 181 forestry rangers from Friuli-Venezia-Giulia, Italy, was examined. Seven (3.9%) sera were positive for Rickettsia conorii and Rickettsia helvetica, as single or dual infections; four of these sera had been found previously to be positive for Borrelia burgdorferi. Antibodies to Coxiella burnetii were detected in five (2.8%) sera, four of which were also positive for B. burgdorferi. These findings indicate that patients in this north-eastern Italian region with fever subsequent to tick-bite should be investigated for Rickettsia and Coxiella infections.

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Six batches of four commercial hybrids of heavy pigs, reared for the production of Italian dry-cured hams, were identified
for having homogeneous feeding and farm conditions. For a total of 235 pigs, slaughtered in the same slaughterhouse,
carcass traits and muscle composition were measured. The pigs were genotyped for single nucleotide polymorphisms
(SNPs) of Na+, K+-ATPase subunit alpha 2 (ATPase, Na+/K+ transporting, alpha 2 (+) polypeptide; ATP1A2), cystatin
B (CSTB), mitochondrial 2,4-dienoyl-CoA reductase 1 (DECR1), leptin (LEP; 3 SNPs), melanocortin receptor 4
(MC4R), melanocortin receptor 5 (MC5R), sarcolipin (SLN) and titin (TTN) genes. All genes showed biallelic polymorphisms
and the alleles were differently distributed between the six batches. Pigs were subsequentely clustered in “lean”
and “fat” using either carcass traits (lean percentage, backfat thickness, loin muscle thickness, ham weight and ham
cover fat thickness: 100 lean and 135 fat) or meat composition data (dry matter, protein, fat and ash of Biceps femoris
and Vastus lateralis and pH after 24 hours: 126 lean and 109 fat). The association of gene polymorphisms with leaness
and fatness of pigs was thus investigated using a logistic regression. ATP1A2, LEP (HinfI polymorphism) and MC4R,
together with sex and ham weight were, included in the model to screen lean and fat pigs classified according to carcass
traits data, yielding a correct classification of 71%. For the lean and fat pigs classified according to muscle composition,
sex, CSTB, DECR1, MC5R and LEP (AciI/TaqI polymorphisms) were included in the regression analysis, that yielded a
66% of pigs correctly classified.
These preliminary results may indicate that some of the selected candidate genes could be associated to production traits
and are worth of further investigations