No abstract

Helicobacter suis is the second most prevalent Helicobacter species in the stomach of humans suffering from gastric disease. This bacterium mainly inhabits the stomach of domesticated pigs, in which it causes gastric disease, but it appears to be absent in wild boars. Interestingly, it also colonizes the stomach of asymptomatic rhesus and cynomolgus monkeys. The origin of modern human-, pig- or non-human primate-associated H. suis strains in these respective host populations was hitherto unknown. Here we show that H. suis in pigs possibly originates from non-human primates. Our data suggest that a host jump from macaques to pigs happened between 100 000 and 15 000 years ago and that pig domestication has had a significant impact on the spread of H. suis in the pig population, from where this pathogen occasionally infects humans. Thus, in contrast to our expectations, H. suis appears to have evolved in its main host in a completely different way than its close relative Helicobacter pylori in humans.

A series of pyrimidine thioethers was synthesized and evaluated for inhibitory properties against wild-type HIV-1 reverse transcriptase (RT) and an RT carrying the resistance-conferring mutation P236L. Modifications of both the pyrimidine and the functionality attached through the thioether yielded several analogues, which demonstrated activity against both enzyme types, with IC50 values as low as 190 nM against wild-type and 66 nM against P236L RT. Evaluation of a select number of pyrimidine thioethers in cell culture showed that these compounds have excellent activity against HIV-1IIIB-WT and retain good activity against a laboratory-derived HIV-1MF delavirdine-resistant variant.

No abstract

The (alkylamino)piperidine bis(heteroaryl)piperizines (AAP-BHAPs) are a new class of human immunodeficiency virus type 1 (HIV-1)-specific inhibitors which were identified by targeted screening of recombinant reverse transcriptase (RT) enzymes carrying key nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance-conferring mutations and NNRTI-resistant variants of HIV-1. Phenotypic profiling of the two most potent AAP-BHAPs, U-95133 and U-104489, against in vitro-selected drug-resistant HIV-1 variants carrying the NNRTI resistance-conferring mutation (Tyr3Cys) at position 181 of the HIV-1 RT revealed submicromolar 90% inhibitory concentration estimates for these compounds. Moreover, U-104489 demonstrated potent activity against BHAP-resistant HIV-1 MF harboring the Pro-2363Leu RT substitution and significantly suppressed the replication of clinical isolates of HIV-1 resistant to both delavirdine (BHAP U-90152T) and zidovudine. Biochemical and phenotypic characterization of AAP-BHAP-resistant HIV-1 IIIB variants revealed that high-level resistance to the AAP-BHAPs was mediated by a Gly-1903Glu substitution in RT, which had a deleterious effect on the integrity and enzymatic activity of virion-associated RT heterodimers, as well as the replication capacity of these resistant viruses.

A novel series of non-nucleoside HCV NS5B polymerase inhibitors was prepared from a (2Z)-2-benzoylamino-3-(4-phenoxy-phenyl)-acrylic acid template. Solution and solid phase analog synthesis focused on the northern region of the template combined with structure based design led to the discovery of several potent and orally bioavailable lead compounds.

Selection of the IIIB strain of human immunodeficiency virus type (HIV-1) resistant to the (alkylamino)piperidine-bis(heteroaryl)piperazine (AAP-BHAP) U-104489 results in substitution of a glycine to glutamate at residue 190 (G190E) of reverse transcriptase (RT). The AAP-BHAP resistant HIV-1 displays reduced in vitro replication capacity [Olmsted, R. A., et. al. (1966) J. Virol. 70, 3698-3705]. We report here that the G190E mutation in recombinant heterodimeric HIV-1 RT, compared to the wild-type RT (G190) or a G190A control mutant, results in a 40% and 80% reduction in the polymerase and RNase H specific enzymatic activities, respectively. A primer-extension assay that allowed determination of DNA elongation by the G190E mutant RT on a heteropolymeric HIV-1 gag-based RNA template showed an overall decrease in DNA polymerization. The size distribution of products generated by G190E RT-associated RNase H digestion of RNA from [35S]poly(rA).poly(dT) was markedly distinct from that of the G190A RT and was consistent with the observed reduction in RT-associated RNase H activity of the G190E RT. When challenged with unlabeled substrates, the G190E RT was relatively nonprocessive with respect to DNA synthesis and RNA degradation. It is concluded that the deleterious effect of the G190E resistance mutation on both of these RT functions is most likely involved in the observed retarded replication capacity of the AAP-BHAP-(U-104489-) resistant HIV-1.

The major route of metabolism of the bis(heteroaryl)piperazine (BHAP) class of reverse transcriptase inhibitors (RTIs), atevirdine and delavirdine, is via oxidative N-dealkylation of the 3-ethyl- or 3-isopropylamino substituent on the pyridine ring. This metabolic pathway is also the predominant mode of metabolism of (alkylamino)piperidine BHAP analogs (AAP-BHAPs), compounds wherein a 4-(alkylamino)piperidine replaces the piperazine ring of the BHAPs. The novel AAP-BHAPs possess the ability to inhibit non-nucleoside reverse transcriptase inhibitor (NNRTI) resistant recombinant HIV-1 RT and NNRTI resistant variants of HIV-1. This report describes an approach to preventing this degradation which involves the replacement of the 3-ethyl- or 3-isopropylamino substituent with either a 3-tert-butylamino substituent or a 3-alkoxy substituent. The synthesis, bioactivity and metabolic stability of these analogs is described. The majority of analogs retain inhibitory activities in enzyme and cell culture assays. In general, a 3-ethoxy or 3-isopropoxy substituent on the pyridine ring, as in compounds 10, 20, or 21, resulted in enhanced stabilities. The 3-tert-butylamino substituent was somewhat beneficial in the AAP-BHAP series of analogs, but did not exert a significant effect in the BHAP series. Lastly, the nature of the indole substitution sometimes plays a significant role in metabolic stability, particularly in the BHAP series of analogs.