[
Aging Cell,
2002]
The papers by Van Voorhies in Free Radical Biology & Medicine (33, 587-596, 2002) and in this journal claim that the major longevity-extending mutations in C. elegans essentially act by reducing metabolic rate as predicted by the rate-of-living theory, and do not alter any metabolically independent mechanism specific to aging. In contrast, we found no evidence of a reduction in metabolic rate in these mutants using different experimental approaches. Now, Van Voorhies challenges the accuracy of our experimental results.
Avery L, Starich TA, Phelen P, Lee RYN, Wyman RJ, Barnes TM, Bacon JP, Hekimi S, Shaw JE, Curtin KA, Baines RA, Todman M, Ford C, Davies JA, Sun Y-a, Stebbings LA
[
Trends Genet,
1998]
In vertebrates, intercellular communication via gap junctions is mediated by the connexin family of molecules, which is made up of at least 13 members. These proteins, which have four transmembrane domains and intracellular C- and N-termini, oligomerize to form hemichannels. Oligomers in the adjacent membranes of two closely apposed cells 'dock' to form intercellular channels, through which ions and small molecules move.
[
Aging Cell,
2002]
The reviews by Braechman et al. and Van Voorhies in this issue of Aging Cell concur on the potential importance of metabolic rate and function to longevity in C. elegans. These reviews differ though, on their assessment of whether long-lived C. elegans mutants have a reduced metabolic rate compared to wild-type worms. At the centre of this disagreement are two main issues: the importance of measurement conditions when conducting metabolic assays on C. elegans, and which techniques are appropriate for measuring the metabolic rate of an organism and subsequent analysis of such data. These issues are interconnected; if the conditions under which an organism's metabolic rate are measured have a large impact on the resulting data, conclusions drawn from data collected from animals under different conditions may be invalid irrespective of the validity of the measurement methods. Conversely, measurement techniques which produce spurious data cannot be used to draw accurate conclusions about the metabolic rate of an organism, regardless of the conditions under which the organism was maintained.
[
FEMS Microbiol Lett,
2014]
Staphylococcus lugdunensis is a human skin commensal organism, but it is considered as a virulent Staphylococcus species. In a previous study, we described the first S.lugdunensis autolysin, AtlL. This enzyme displays two enzymatic domains and generates two peptidoglycan hydrolases, an N-acetylmuramoyl-l-alanine amidase and an N-acetylglucosaminidase. In this study, to further investigate the functions of this autolysin, a atlL mutant was constructed. The microscopic examination of the mutant showed cell aggregates and revealed a rough outer cell surface demonstrating, respectively, the roles of AtlL in cell separation and peptidoglycan turnover. This atlL mutant exhibited a lower susceptibility to Triton X-100-induced autolysis assays and appears to be more resistant to cell wall antibiotic-induced lysis and death compared with its parental strain. The atlL mutation affected the biofilm formation capacity of S.lugdunensis. Furthermore, the atlL mutant showed trends toward reduced virulence using the Caenorhabditis elegans model. Overall, AtlL appears as a major cell wall autolysin of S.lugdunensis implicated in cell separation, in stress-induced autolysis and in bacterial pathogenesis.