Putative pathways fueling anaerobic mitochondrial respiration

Abstract

Tumor interiors undergo prolonged anoxia; however, the pathways involved have not been identified. Since NO and H2S function in prokaryotic anaerobic respiration, the effect their pathway elements have on HeLa 229 cell viability was measured after 10 days anaerobic incubation. Arginine or xanthine (NO pathway precursors) increased cell viability (13.1- and 4.4-fold, respectively). The H2S pathway precursor, cysteine, also enhanced viability (9.8-fold), as did H2S donor GYY4137, or inhibitor of glutathione synthesis, propargylglycine, (40- and 85-fold, respectively). These results demonstrate that cell viability after extended anaerobic incubation (10 days) can be modulated by affecting NO or H2S pathways.

Method for the growth of Herpes Simplex Virus (HSV-1 and HSV-2) in an oxygen-free environment

“…While both HSV-1 and HSV-2 can cause vaginal infections with lesions, HSV-2 is most commonly associated with disease at this site [18,19]. To date, the differences between HSV-1 and HSV-2 in their relative ability to cause vaginal infections has not been well characterized because until recently, no in vitro model system enabled the measurement of long-term anaerobic intracellular viral replication [5,6,7,20]. Using a novel anaerobic (0% oxygen) cell growth model system developed by the Plotkin/Sigar Laboratory, the ability of HSV-1 and HSV-2 to anaerobically infect HeLa cells, express replication-associated early proteins, and produce viable progeny were determined.…”

“…Previous studies assessing cell growth under in vitro anoxic conditions (0-0.3% O2) show that cell physiology, in the absence of oxygen as the terminal electron acceptor for the mitochondrial cytochrome oxidase system, differs from cell physiology when grown under CO2-enriched atmospheric oxygen (21% O2), i.e., a hyperbaric growth environment [5,6,7]. Since the subsequent decrease in oxygen tension, in addition to the pathogen's restriction to an intracellular environment, are indicators that HSV replicates in low oxygen concentrations in vivo, it is possible to gain insightful knowledge of the host-pathogen interactions involved under anaerobic growth conditions using the anaerobic cell model previously described to confirm that HSV1/2 anaerobic replication parallels that of aerobic growth [5,6,7]. The focus of this study is to determine the methodology for growing HSV1/2 anaerobically and assess its replication characteristics compared to standard growth conditions (5% CO2 in air).…”