Saline and buffers minimize the action of interfering factors in the bacterial endotoxins test

Fujita, Yuu; Tokunaga, Tetsuhiro; Kataoka, Hirofumi

doi:10.1016/j.ab.2010.10.014

Cited by 24 publications

(17 citation statements)

References 17 publications

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“…BES and Tris were found to affect the results of bacterial endotoxin tests in the presence of different metal ions. 72 In the study of photosystem II inhibition by Cu(II), it was concluded that Tris, tricine and TES complexed with Cu(II), with substantial effects on the nal results. 7 The choice of buffer also inuenced the determination of the thermodynamic parameters associated with the interaction of alkaline metal ions with citric acid.…”

Section: Hepesmentioning

confidence: 99%

(Un)suitability of the use of pH buffers in biological, biochemical and environmental studies and their interaction with metal ions – a review

et al. 2015

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The use of buffers to maintain the pH within a desired range is a very common practice in chemical, biochemical and biological studies.Among them, zwitterionic N-substituted aminosulfonic acids, usually known as Good'sbuffers, although widely used, can complex metals and interact with biological systems. The present work reviews, discusses and updates the metal complexation characteristics of thirty one commercially available buffers. In addition, their impact on biological systems is also presented. The influences of these buffers on the results obtained in biological, biochemical and environmental studies, with special focus on their interaction with metal ions, are highlighted and critically reviewed. Using chemical speciation simulations, based on the current knowledge of the metal-buffer stability constants, a proposal of the most adequate buffer to employ for a given metal ion is presented.

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Section: Hepesmentioning

confidence: 99%

(Un)suitability of the use of pH buffers in biological, biochemical and environmental studies and their interaction with metal ions – a review

et al. 2015

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“…These methods have been described in the pharmacopoeia of many countries (Smulders et al, 2012). Nevertheless, many reports have demonstrated interference of engineered NM with one or more formats of the LAL test (Cooper, 1990;Bohrer et al, 2001;Fujita et al, 2011). Smulders and co-workers reported that some NMs, including TiO 2 , Ag, CaCO 3 , and SiO 2, interfere with the LAL test (Smulders et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

Graphene and carbon nanotubes activate different cell surface receptors on macrophages before and after deactivation of endotoxins

Lahiani

Gokulan

Williams

et al. 2017

J of Applied Toxicology

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Nanomaterial synthesis and handling in a non-sterile environment can result in the final product becoming contaminated with bacterial endotoxin or lipopolysaccharides (LPB). During toxicological testing, the effects caused by endotoxin-contaminated nanomaterials can be misinterpreted in the end-point analysis (such as cytotoxicity and immune responses) and could result in erroneous conclusions. The objective of this study was twofold: (i) to test different carbonbased nanomaterials (CBNs) [pristine graphene and multi-wall carbon nanotubes (MWCNTs)] for the presence of endotoxin and develop strategies for depyrogenation, and (ii) to compare the immune response exhibited by macrophages after exposure to native CBNs versus depyrogenated CBNs. The gel-clot limulus amebocyte lysate (LAL) and chromogenic-based LAL assays were used to detect endotoxins. Results revealed that the CBNs contained greater amounts of endotoxin than are approved by major regulatory agencies (0.5 EU ml À1). Three repeated cycles of autoclaving reduced the endotoxin in the test materials. Macrophages were incubated with pyrogenated and depyrogenated pristine graphene and MWCNTs to test differences in phagocytosis, cytotoxicity, and expression of genes involved in macrophage activation. The uptake of depyrogenated CBNs was significantly reduced as compared with pyrogenated CBNs. Exposure of macrophages to depyrogenated CBNs resulted in a distinct pattern of gene expression for TLR signaling, NOD-like receptor signaling, and downstream signal transduction molecules. Furthermore, macrophages exposed to both types of CBNs showed the downregulation of TLR5 and NLRC4 inflammasomes. The results of this study reaffirm that assessment of endotoxin and other bacterial contamination is critical when evaluating the cellular toxicity of nanomaterials. Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

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“…We previously reported that some substances, including iron sulfate, strongly affect the LAL reaction and act on endotoxins directly, altering the state of endotoxin complexes in solution; such interference could be minimized by preparing sample solutions in saline, D‐PBS, BES, or Tris buffers instead of water (Fujita et al . ).…”

Section: Introductionmentioning

confidence: 97%

“…We sought to elucidate the mechanisms through which iron sulfate interferes with lipid A function because this substance strongly and directly acts on endotoxins (Fujita et al . ). To this end, we analysed the negative charge, hydrophobic interactions, complex formation and structures of inactivated lipid A by size‐exclusion high‐performance liquid chromatography (HPLC), anion‐exchange HPLC and reverse‐phase liquid chromatography/mass spectrometry (LC/MS), respectively.…”

Section: Introductionmentioning

confidence: 97%

Iron sulfate inhibits Limulus activity by induction of structural and qualitative changes in lipid A

Fujita¹,

Nabetani²

2013

J Appl Microbiol

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Aims: The bacterial endotoxins test (BET) is a sensitive assay for measuring endotoxin levels in solution and uses the limulus amebocyte lysate (LAL) coagulation reaction. We sought to identify the mechanisms through which certain substances interfere with the interaction between LAL and bacterial lipopolysaccharide (LPS). Methods and Results: Endotoxin lipid A was inactivated by the addition of iron sulfate, which acted on endotoxin directly and strongly inhibited LAL coagulation activity. Size-exclusion, anion-exchange and reverse-phase liquid chromatography/mass spectrometry were used to examine changes in inactivated lipid A in terms of complex formation, negative charge status, hydrophobic interaction and structure. Furthermore, we verified the involvement of the lipid A phosphoryl group in the interference of iron sulfate with lipid A-factor C binding activity. Iron sulfate-inactivated lipid A was cleaved at its glycosidic bond, resulting in loss of hydrophobic interactions and disruption of lipid A complexes without alteration of negative charge status and lipid A-factor C interaction. Conclusions: Lipid A cleavage was a direct result of interfering factors, including iron sulfate, which acted on endotoxin directly to disrupt lipid A complexes rather than interfering with LAL coagulation. Significance and Impact of the Study: Our data provide new insights into the mechanisms of lipid A activity.

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Saline and buffers minimize the action of interfering factors in the bacterial endotoxins test

Cited by 24 publications

References 17 publications

(Un)suitability of the use of pH buffers in biological, biochemical and environmental studies and their interaction with metal ions – a review

(Un)suitability of the use of pH buffers in biological, biochemical and environmental studies and their interaction with metal ions – a review

Graphene and carbon nanotubes activate different cell surface receptors on macrophages before and after deactivation of endotoxins

Iron sulfate inhibits Limulus activity by induction of structural and qualitative changes in lipid A

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