Redox-active metals in commercial preparations of lipopolysaccharide: implications for studies of cellular responses to bacterial products

Abstract

SummaryThe mechanisms by which lipopolyaccharide (LPS) activates cells have been the subject of intense investigation for many years. Whereas much information on this process has been collected for mammalian species, little is known about the signalling pathways operative in other animals. One general mode of cellular activation that has been recently proposed for pathways independent of the primary mammalian LPS receptor, CD14, involves reactive oxygen species (ROS) as intermediates in LPSinduced signalling pathways. Therefore, we used 2 ¢ ,7 ¢ -dichlorodihydrofluorescein, a fluorogenic probe of redox activity, to examine LPS-induced oxidative responses of a macrophage-like cell line from the rainbow trout, RTS11. Lipopolysaccharide dosedependently increased oxidation of this probe by RTS11 cells, and a variety of other cell lines. This process was inhibited by catalase, superoxide dismutase and N G -methylarginine citrate, an inhibitor of nitric oxide synthases, suggesting the involvement of a diverse assortment of cellular ROS. More careful dissection of this phenomenon led us to conclude that the increase in oxidation was, in fact, due almost entirely to metals, particularly copper, in some LPS preparations, which is something to consider when experimenting with LPS.

A highly phagocytic cell line TO from Atlantic salmon is CD83 positive and M-CSFR negative, indicating a dendritic-like cell type

“…In addition, there were little or no observable NO production and the cells were MPO negative. Among the other phagocytic cell lines, RTS11 had neither respiratory burst nor NO production in response to stimulation, for SHK this is not described, while the cell lines, CLC and GMCL showed respiratory burst activity [1][2][3][4]52]. As bactericidal activity is lacking, low or not described, the bactericidal ability may not always or completely be linked to respiratory burst in such cells.…”

Establishment and characterization of a liver cell line from silver pomfret (Pampus argenteus) for studying fish health

“…Our results indicated that Fish are constantly exposed to microorganisms in the aquatic environment, many of which are bacterial pathogens (Vanamala et al, 2022). LPS is a heat-stable endotoxin derived from gramnegative bacteria that can mediate immune responses and extensively used to mimic bacterial infection in a number of fish species (Brubacher et al, 2003;Cavaillon, 2018;Lee et al, 2013).…”

“…Fish are constantly exposed to microorganisms in the aquatic environment, many of which are bacterial pathogens (Vanamala et al, 2022). LPS is a heat‐stable endotoxin derived from gram‐negative bacteria that can mediate immune responses and extensively used to mimic bacterial infection in a number of fish species (Brubacher et al, 2003; Cavaillon, 2018; Lee et al, 2013). Administration of LPS in vivo has been demonstrated to affect reproductive processes in female rainbow trout by increasing apoptosis of ovarian follicle cells and by advancing the time of ovulation, resulting in a decrease in egg quality and embryonic survival (Crespo et al, 2010).…”

Pulmonary Nocardiosis; Similarity to Tuberculosis (A Bacteriological and Proteomics Study)

“…Two-dimensional (2-D) gel electrophoresis of pulse-labeled proteins revealed a global analysis of protein synthesis and turnover in Escherichia coli (Weichart et al, 2003). Comparative proteomics of the human pathogen Campylobacter jejuni revealed an important first step in characterizing strain differences potentially responsible for different disease outcomes associated with this organism (Brubacher et al, 2003). Several studies subjected Mycobacterium tuberculosis to comprehensive proteomic analysis.…”