Ribavirin is not a functional mimic of the 7-methyl guanosine mRNA cap

Ribavirin is a guanosine ribonucleoside analog that displays broad-spectrum anti-viral activity and is currently used for the treatment of some viral infections. Ribavirin has recently been proposed to also be a mimic of the 7-methyl guanosine cap found at the 5' end of mRNAs. To obtain supporting functional data for this hypothesis, we assessed the ability of ribavirin triphosphate to interfere with the interaction between eIF4E and 7-methyl guanosine capped mRNA. In chemical cross-linking assays, cap-affinity chromatography, and cap-dependent translation assays, ribavirin was unable to function as a cap analog.     

Simultaneous removal of phenol, ortho- and para-cresol by mixed anaerobic consortia.

Two different anerobic consortia, one removing phenol and ortho (o-) cresol and other removing para(p-) cresol, were cultivated in serum bottles using whey as cosubstrate substitute for proteose peptone. Phenol and p-cresol removal with the phenol-removing consortium were the same with 0.0125% (w/v) whey as with 0.05% proteose peptone. For the other consortium, 8 days were required to decrease the p-cresol concentration from 35 to 2 mg/L with 0.025% whey, while 35 days were required to achieve a similar removal with 0.5% proteose peptone. The two consortia were mixed and cultivated with 0.025% whey. Phenolic compound removal with the mixed consortia was as good as that achieved by each of the two initial consortia against their respective substrates. This removal activity was maintained after several transfers. In a continuous upflow fixed-film reactor, the mixed consortia removed over 98% of 150 mg/L of phenol and 35 mg/L of each o- and p-cresol in the influent at 29 degrees C, with 0.025% whey as cosubstrate. The hydraulic retention time (HRT) was 0.25 day, corresponding to a phenolic compound volumic loading rate of 880 mg/(L of reactor x day). Once the continuous flow reactor achieved constant phenolic compound removal, no intermediates were found in the effluent, while in serum bottles, m-toluic acid, an o-cresol intermediate, accumulated. Measurements of the specific activity for the uptake of different substrates demonstrated the presence of all trophic groups involved in methanogenic fermentation. These activities were, in mg of substrate/(g of volatile suspended solids x day), as follows: 849 +/- 25 for the acidogens; 554 +/- 15 for the acetogens; 934 +/- 37 for the aceticlastic methanogens; and 135 +/- 15 for the hydrogenophilic methanogens. Electron micrographs of the mixed consortia showed seven different morphological bacterial types, including Methanotrix-like bacteria.     

A farm-level study of risk factors associated with the colonization of broiler flocks with <Emphasis Type="Italic">Campylobacter</Emphasis> spp. in Iceland, 2001 – 2004

Background  

Following increased rates of human campylobacteriosis in the late 1990's, and their apparent association with increased consumption of fresh chicken meat, a longitudinal study was conducted in Iceland to identify the means to decrease the frequency of broiler flock colonization with Campylobacter. Our objective in this study was to identify risk factors for flock colonization acting at the broiler farm level.     

Insights into the molecular determinants involved in cap recognition by the vaccinia virus D10 decapping enzyme

Decapping enzymes are required for the removal of the 5′-end ^m7GpppN cap of mRNAs to allow their decay in cells. While many cap-binding proteins recognize the cap structure via the stacking of the methylated guanosine ring between two aromatic residues, the precise mechanism of cap recognition by decapping enzymes has yet to be determined. In order to get insights into the interaction of decapping enzymes with the cap structure, we studied the vaccinia virus D10 decapping enzyme as a model to investigate the important features for substrate recognition by the enzyme. We demonstrate that a number of chemically modified purines can competitively inhibit the decapping reaction, highlighting the molecular features of the cap structure that are required for recognition by the enzyme, such as the nature of the moiety at positions 2 and 6 of the guanine base. A 3D structural model of the D10 protein was generated which suggests amino acids implicated in cap binding. Consequently, we expressed 17 mutant proteins with amino acid substitutions in the active site of D10 and found that eight are critical for the decapping activity. These data underscore the functional features involved in the non-canonical cap-recognition by the vaccinia virus D10 decapping enzyme.     

Carboxylation of o-cresol by an anaerobic consortium under methanogenic conditions.

The metabolism of o-cresol under methanogenic conditions by an anaerobic consortium known to carboxylate phenol to benzoate was investigated. After incubation with the consortium at 29 degrees C for 59 days, o-cresol was transformed to 3-methylbenzoic acid, which was not further metabolized by the consortium. Proteose peptone in the culture medium was essential for the transformation of o-cresol. In addition, a transient compound detected in the culture was identified as 4-hydroxy-3-methylbenzoic acid. o-Cresol-6d was transformed by the consortium to deuterated hydroxy-methylbenzoic acid and deuterated methylbenzoic acid. These results demonstrate that o-cresol is carboxylated in the para position relative to the phenolic hydroxyl group and dehydroxylated by the anaerobic consortium.