Hyperthermophilic methanogenic archaea act as high-pressure CH4 cell factories.

Bioprocesses converting carbon dioxide with molecular hydrogen to methane (CH4) are currently being developed to enable a transition to a renewable energy production system. In this study, we present a comprehensive physiological and biotechnological examination of 80 methanogenic archaea (methanogens) quantifying growth and CH4 production kinetics at hyperbaric pressures up to 50 bar with regard to media, macro-, and micro-nutrient supply, specific genomic features, and cell envelope architecture. Our analysis aimed to systematically prioritize high-pressure and high-performance methanogens. We found that the hyperthermophilic methanococci Methanotorris igneus and Methanocaldococcoccus jannaschii are high-pressure CH4 cell factories. Furthermore, our analysis revealed that high-performance methanogens are covered with an S-layer, and that they harbour the amino acid motif Tyrα444 Glyα445 Tyrα446 in the alpha subunit of the methyl-coenzyme M reductase. Thus, high-pressure biological CH4 production in pure culture could provide a purposeful route for the transition to a carbon-neutral bioenergy sector.

Nelfinavir and nelfinavir analogs block site-2 protease cleavage to inhibit castration-resistant prostate cancer.

Nelfinavir and its analogs inhibit proliferation and induce apoptosis of castration-resistant prostate cancer through inhibition of site-2 protease (S2P) activity, which leads to suppression of regulated intramembrane proteolysis. Western blotting in nelfinavir and its analog treated cells confirms accumulation of precursor SREBP-1 and ATF6. Nelfinavir and its analogs inhibit human homolog M. jannaschii S2P cleavage of an artificial protein substrate CED-9 in an in vitro proteolysis assay in a dose-dependent manner. Nelfinavir and its analogs are more potent inhibitors of S2P cleavage activity than 1,10-phenanthroline, a metalloprotease-specific inhibitor. Further, cluster analysis of gene expression from treated DU145 and PC3 cell lines demonstrate a close similarity of nelfinavir, its analogs, and 1,10-phenanthroline. These results show nelfinavir and its analogs inhibit castration-resistant prostate cancer proliferation by blocking regulated intramembrane proteolysis through suppression of S2P cleavage activity. This leads to accumulation of precursor SREBP-1 and ATF6, and development of insufficient reserves of their transcriptionally-active forms. The present results validate S2P and regulated intramembrane proteolysis as novel therapeutic targets for castration-resistant prostate cancer therapeutics. A clinical trial of nelfinavir or its analogs should be developed for castration-resistant prostate cancer.