Delineation of two Helicobacter bilis genomospecies: implications for systematics and evolution

The evolution and taxonomy of Helicobacter bilis strains isolated in Italy and Finland were studied by phylogenetic analysis of different genes, comparative analysis of small rRNA gene intervening sequence (IVS), amplified fragment length polymorphism analysis and DNA\u2013DNA hybridization. The results of this study divided the H. bilis strains into two distinct and divergent genomic groups. In the absence of a specific phenotype or pathotype to distinguish these groups, however, they may be referred to as two genomospecies: H. bilis sensu stricto and Helicobacter sp. FL56. The phylogenetic network of gyrB and ureB gene sequences, as well as the comparative analysis of small rRNA gene IVS, suggests independent evolution of the two genomospecies. In particular, Helicobacter sp. FL56 seems to be the result of adaptation of an ancestral H. bilis strain in a new host. The phenomenon of adaptation to different hosts, or different intestinal niches in the same host, associated with high mutation and recombination rates could explain the evolution and the complex taxonomy of the genus Helicobacter. A comprehensive phylogenomics study of this genus would be useful to properly investigate this hypothesis

Using Room Temperature Ionic Liquids as Solvents to Probe Structural Effects in Electro-Reduction Processes. Electrochemical Behavior of Mutagenic Disperse Nitroazo Dyes in Room Temperature Ionic Liquids

The electrochemical reduction of the disperse azo dyes Red1, Red13 and Orange1 (Or1) was investigated in the RTILs [C4mim][NTf2] and [C4mpyrr][NTf2], and in contrast with their behavior in conventional aprotic solvents, was shown to proceed via a reversible one electron step to form stable radical anion, which is further reduced at more negative potentials to the dianion. In [C4mpyrr][NTf2], cleavage of the N-H bond on the secondary amine was inferred for Orange1, and the ease at which this cleavage occurred is rationalized in terms of acidity of the amine moiety. The ease of reduction was observed to decrease in the order Or1 > Red13 > Red1, and is related to the electron delocalization within the molecule and the electron withdrawing power of the substituents. The dyes were then oxidized, and Red1 and Red13, bearing an aliphatic amine, were oxidized in a reversible one electron step, to generate the radical cations. The presence of a primary aromatic amine in Or1 provokes a positive shift in the potential of the oxidation peak and shows reversible voltammetry only at scan rates above 200 mV s-1. The ease of oxidation decreases in the order Red1 > Red13 > Or1, and is thought to relate to the detected mutagenic activity of the dyes. © 2009 by ESG

Occurrence of Campylobacter spp. in Italian rabbit farms

In order to investigate the occurrence of Campylobacter spp. in rabbits reared in intensive and rural farms, the caecal contents of 39 animals from 13 different farms (3 rabbits per farm) were collected from April to November 2007. The whole intestinal tract from each rabbit was obtained just after evisceration at the slaughterhouse or during necroscopy, and processed within 4 hours. Approximately 5 g of caecal contents were squeezed into 5 ml of sterile saline and shaken in order to obtain a homogenous suspension. Samples were inoculated by streaking 10 μl of each suspension directly onto four different selective fresh media: Blaser-Wang\u2019s Agar (Oxoid), Skirrow\u2019s Agar (Oxoid), Nutrient Agar N\ub02 (Oxoid) 5% sheep blood plus CAT Selective Supplement (CAT, Oxoid) and modified Charcoal Cefoperazone Deoxycholate Agar (mCCDA, Oxoid). In addition, samples were inoculated on a non selective medium such as Nutrient Agar N\ub02 (Oxoid) 5% sheep blood using a modified filter technique of Steele & McDermott. All plates were incubated in a jar at 37\ub0C\ub11 under a microaerobic atmosphere with hydrogen and examined daily for growth up to 12 days. From each sample, 3 colonies showing the same morphotype referable to Gram negative, curved or spiral rod bacteria, were cloned. All the selected colonies were subjected to genus-specific PCR for Campylobacter. Positive isolates were submitted to the PCRs specific for C. jejuni, C. coli, C. upsaliensis, C. helveticus and C. lari. The isolates which resulted negative to the species-specific PCRs were subjected to rpoB sequence phylogenetic analysis. A total of 36 out of 39 animals (92.3%) and all the 13 farms resulted positive for Campylobacter. All isolates were positive for Campylobacter genus PCR but negative for all the species-specific PCRs tested. Phylogenetic analysis based on the partial nucleotide rpoB sequences of 13 isolates (one strain per farm) randomly selected and the reference strains showed that all the rabbit isolates clustered together in a tight clade. This cluster was clearly separated from all the other Campylobacter species with high bootstrap values (100), indicating that these isolates may belong to a new species. This survey allowed reporting the occurrence of a probably new Campylobacter species in the caecal contents of farmed rabbits in Italy. Further studies are necessary to describe it and evaluate its possible pathogenic effect on rabbit as well as the eventual zoonotic role

The electrochemical reduction of the purines guanine and adenine at platinum electrodes in several room temperature ionic liquids

The reduction of guanine was studied by microelectrode voltammetry in the room temperature ionic liquids (RTILs) N-hexyltriethylammonium bis (trifluoromethanesulfonyl) imide [N(6,2,2,2)][N(Tf)(2)], 1-butyl-3-methylimidazolium hexafluorosphosphate [C(4)mim][PF(6)], N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide [C(4)mpyrr][N(Tf)(2)], 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C(4)mim][N(Tf)(2)], N-butyl-N-methyl-pyrrolidinium dicyanamide [C(4)mpyrr][N(NC)(2)] and tris(P-hexyl)-tetradecylphosphonium trifluorotris(pentafluoroethyl)phosphate [P(14,6,6,6)][FAP] on a platinum microelectrode. In [N(6,2,2,2)][NTf(2)] and [P(14,6,6,6)][FAP], but not in the other ionic liquids studied, guanine reduction involves a one-electron, diffusion-controlled process at very negative potential to produce an unstable radical anion, which is thought to undergo a dimerization reaction, probably after proton abstraction from the cation of the ionic liquid. The rate of this subsequent reaction depends on the nature of the ionic liquid, and it is faster in the ionic liquid [P(14,6,6,6)][FAP], in which the formation of the resulting dimer can be voltammetrically monitored at less negative potentials than required for the reduction of the parent molecule. Adenine showed similar behaviour to guanine but the pyrimidines thymine and cytosine did not; thymine was not reduced at potentials less negative than required for solvent (RTIL) decomposition while only a poorly defined wave was seen for cytosine. The possibility for proton abstraction from the cation in [N(6,2,2,2)][NTf(2)] and [P(14,6,6,6)][FAP] is noted and this is thought to aid the electrochemical dimerization process. The resulting rapid reaction is thought to shift the reduction potentials for guanine and adenine to lower values than observed in RTILs where the scope for proton abstraction is not present. Such shifts are characteristic of so-called EC processes where reversible electron transfer is followed by a chemical reaction