Related Experiment Video
Updated: Oct 2, 2026
Determination of Sialic Acids in Liver and Milk Samples of Wild-type and CMAH Knock-out Mice.
Published on: July 14, 2017
Muramic acid is not generally present in the human spleen as determined by gas chromatography-tandem mass
Michael P Kozar1, Jon D Laman, Alvin Fox
1Department of Microbiology & Immunology, University of South Carolina, School of Medicine, Columbia, South Carolina 29208, USA.
Abstract:
It has been hypothesized that bacterial debris may accumulate in tissues of the reticuloendothelial system (RES) serving as an inflammatory stimulus for human disease. In support of this hypothesis, muramic acid (Mur), a component of bacterial peptidoglycan (PG), has previously been reported to be present in culture-negative human spleen. High-performance liquid chromatography (HPLC) was employed in these analyses, and a peak was detected at the retention time of Mur. However, HPLC is best used as a screening technique, and it is vital that these tentative observations be reexamined by the state-of-the-art approach (gas chromatography-tandem mass spectrometry [GC-MS(2)]). Indeed, in the present work using GC-MS(2), Mur was not detected in six out of seven human spleens previously examined by HPLC. However, Mur was categorically detected at minute concentrations, 50 ppb, in one spleen. In conclusion, since Mur is not generally found in culture-negative human spleen, in future studies, these tissues can serve as negative controls. The study of Mur levels in inflammation (e.g., reactive arthritis) could prove important in testing the hypothesis that bacterial debris persisting in tissues could serve as a depot inciting diseases of unknown etiology.
Insights
Muramic acid, a bacterial component, was generally not detected in human spleen tissue. This finding suggests spleen tissue can serve as a negative control in future inflammation studies.
Area of Science:
- Microbiology
- Immunology
- Pathology
Background:
- Bacterial debris in the reticuloendothelial system (RES) may trigger human diseases.
- Muramic acid (Mur), a bacterial peptidoglycan (PG) component, was previously reported in human spleen.
- High-performance liquid chromatography (HPLC) indicated Mur presence, necessitating confirmation.
Purpose of the Study:
- To re-examine the presence of Mur in human spleen tissue using a more advanced technique.
- To validate or refute previous findings of Mur in culture-negative human spleen.
- To assess the utility of human spleen as a negative control in future research.
Main Methods:
- Gas chromatography-tandem mass spectrometry (GC-MS(2)) was used for precise detection.
- Seven human spleen samples previously analyzed by HPLC were re-analyzed.
- Quantification of Mur was performed using GC-MS(2) at parts per billion (ppb) levels.
Main Results:
- Mur was not detected in six of the seven human spleen samples.
- Minute concentrations of Mur (50 ppb) were detected in one spleen sample.
- The study challenges the general presence of Mur in culture-negative human spleen.
Conclusions:
- Culture-negative human spleen generally does not contain detectable levels of Mur.
- Human spleen tissue can be utilized as a negative control in future studies.
- Investigating Mur levels in inflammatory conditions like reactive arthritis may validate the bacterial debris hypothesis.
Related Concept Videos
01:15Mass Spectrometry of Amines
01:30NMR and Mass Spectroscopy of Carboxylic Acids
While α protons of carboxylic acids absorb at 2–2.5 ppm, β protons absorb further upfield.
Carboxylic acids are easily identified by dissolving them in deuterium oxide, which results in a rapid exchange of the acidic protons with deuterium. This leads to the disappearance of the acidic...