Methanol production from the degradation of pectin by human colonic bacteria

Siragusa, Roy; Cerda, James J.; Baig, M. Mansoor; Burgin, Charles W.; Robbins, Frank

doi:10.1093/ajcn/47.5.848

Cited by 51 publications

(33 citation statements)

References 15 publications

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“…Methanol has been shown to be produced from pectins by human colonic bacteria in uitro (Siragusa et al 1988). We have also found that PCW polysaccharides are extensively degraded in the rat gut.…”

Section: Discussionmentioning

confidence: 57%

The metabolism and fate of [methyl‐¹⁴C] and [uronate‐6‐¹⁴C]pectin‐labelled dietary plant cell walls in the rat

1994

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The metabolism of dietary plant cell walls (PCW) was followed in the rat using PCW isolated from spinach cell cultures which ~ere'~C-labelled in the galacturonic acid residues (using ~-[6-'~C]ghcuronic acid, 2 85% of the 14C was confined to the C-6 position of pectic galacturonic acid residues) or the methyl ester groups (using ~-[rnethyl-'~C]methionine, 90% of the 14C was confined to methyl ester groups and 10% of the 14C in methyl ether groups) of pectin. Eighteen hours after gavage, only 5-10% of the 14C was recovered in the gut contents and faeces. Some of the 14C derived from the [methyl-14C]pectinlabelled PCW was present in the liver (2-4%) and the pelt (6%). In the liver the I4C was mainly in phospholipids, whereas in the pelt the 14C was found in protein (mainly alanine residues) and fatty acids esterified to cholesterol. The livers from rats fed [~ronate-6-~~C]pecfin-labelled PCW contained less I4C (1 %) but more I4C was found in the pelt (12-15%). In the liver the 14C was found in phospholipid but in the pelt the label was exclusively found in amino acid residues. Pectin in intact PCW is extensively degraded in the caecum and colon and the products absorbed and metabolised by the host. These products may be important sources of energy and of precursors of structural compounds such as proteins and lipids.

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Section: Discussionmentioning

confidence: 57%

The metabolism and fate of [methyl‐¹⁴C] and [uronate‐6‐¹⁴C]pectin‐labelled dietary plant cell walls in the rat

1994

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“…Fumarate and succinate are the intermediates of propionate production from carbohydrates through the succinate pathway, which explains the reduced concentrations of these two metabolites. Human colonic bacteria also produce methanol via the degradation of pectins, which are a class of heterogeneous polysaccharides and can be found in the inter-and intra-cell walls of most fruits and vegetables 23 . Higher concentrations of methanol were found after 5-h room temperature storage, which indicate that fecal bacteria were able to further degrade indigestible dietary components when samples were stored at room temperature.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Optimized Sample Handling Strategy for Metabolic Profiling of Human Feces

Gratton¹,

Phetcharaburanin²,

Mullish³

et al. 2016

Anal. Chem.

156

133

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Fecal metabolites are being increasingly studied to unravel the host-gut microbial metabolic interactions. However, there are currently no guidelines for fecal sample collection and storage based on a systematic evaluation of the effect of time, storage temperature, storage duration and sampling strategy. Here we derive an optimized protocol for fecal sample handling with the aim of maximizing metabolic stability and minimizing sample degradation. Samples obtained from five healthy individuals were analyzed to assess topographical homogeneity of feces, and to evaluate storage duration-, temperature-and freeze-thaw cycle-induced metabolic changes in crude stool and fecal water using a 1 H NMR spectroscopy-based metabolic profiling approach. Inter-individual variation was much greater than that attributable to storage conditions. Individual stool samples were found to be heterogeneous and spot sampling resulted in a high degree of metabolic variation. Crude fecal samples were remarkably unstable over time and exhibited distinct metabolic profiles at different storage temperatures. Microbial fermentation was the dominant driver in time-related changes observed in fecal samples stored at room temperature and this fermentative process was reduced when stored at 4°C. Crude fecal samples frozen at -20°C manifested elevated amino acids and nicotinate and depleted short chain fatty acids compared to crude fecal control samples. The relative concentrations of branched-chain and aromatic amino acids significantly increased in the freeze-thawed crude fecal samples, suggesting a release of microbial intracellular contents. The metabolic profiles of fecal water samples were more stable compared to crude samples. Our recommendation is that intact fecal samples should be collected, kept at 4°C or on ice during transportation, and extracted ideally within 1 h of collection, or a maximum of 24 h. Fecal water samples should be extracted from a representative amount (~15 g) of homogenized stool sample, aliquoted and stored at < -20°C, avoiding further freeze-thaw cycles.Metabolic profiling of biofluids and tissues generates data on a wide range of metabolites and provides extensive metabolic information on multiple biological processes in complex superorganisms such as mammals. Although urine and blood are often used to investigate systemic responses of animals and humans to various environmental stimuli or therapeutic interventions 1 , the search for disease biomarkers in fecal samples and studies on host-microbial interactions have intensified over the last decade. The human intestinal tract harbors >100 trillion microbial cells 2 and these microbes exert their influences on the human host primarily by metabolic signaling and therefore optimized methodologies for the study of microbial metabolic footprint is crucial to this field. Mounting evidence shows that the microbial composition and its collective metabolic activity profoundly impacts host physiology and modulates the disease risk of the host 3 . To investigate th...

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“…Even if one avoids aspartame-bearing products, normal dietary exposure to methanol may still occur from consumption of certain fruits, vegetables and juices with high pectin content (i.e., direct ingestion; Butchko and Kotsonis, 1991;Frenkel et al, 1998). Furthermore, though some of the pectin content is converted directly to methanol in these food products, unprocessed pectin can itself be converted in the gut to methanol by the actions of local bacteria (i.e., another indirect form of ingestion; Siragusa et al, 1988;Lindenger et al, 1997), again resulting in substantive daily increases in blood methanol content.…”

Section: Introductionmentioning

confidence: 99%

Effect of methanol intoxication on spcific immune functions of albino rats

et al. 2006

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Our previous studies revealed that methanol intoxication significantly altered the non-specific immune functions in albino rats. The present investigation focuses on the effect of methanol on certain specific immune functions of cell mediated immunity such as footpad thickness, leukocyte migration inhibition test (LMI) and antibody levels. In addition, serum interleukins (IL-2, IL-4, TNF-alpha and IFN-gamma), and splenic lymphocyte subsets were measured after an immune challenge. The specific immune function tests were carried out in three different groups of albino rats, which include control, 15 and 30 days methanol intoxication. Our study reports that animal body weight, organ weight ratio, lymphoid cell counts, footpad thickness, antibody titer, IL-2, TNF-alpha, IFN-gamma, Pan T cell, CD4, macrophages, MHC class II molecule expression, and B cell counts were significantly decreased compared to control animals nevertheless, LMI, IL-4, and DNA single strand breakage were increased significantly. Plasma corticosterone level was significantly increased in the 15 days group whereas the 30 days methanol intoxication group showed considerable decrease in corticosterone level compared with control animals. Therefore, our investigation concluded that repeated exposure of methanol profoundly suppressed the cell mediated and humoral immune functions in albino rats.

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Methanol production from the degradation of pectin by human colonic bacteria

Cited by 51 publications

References 15 publications

The metabolism and fate of [methyl‐¹⁴C] and [uronate‐6‐¹⁴C]pectin‐labelled dietary plant cell walls in the rat

The metabolism and fate of [methyl‐¹⁴C] and [uronate‐6‐¹⁴C]pectin‐labelled dietary plant cell walls in the rat

Optimized Sample Handling Strategy for Metabolic Profiling of Human Feces

Effect of methanol intoxication on spcific immune functions of albino rats

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Methanol production from the degradation of pectin by human colonic bacteria

Cited by 51 publications

References 15 publications

The metabolism and fate of [methyl‐14C] and [uronate‐6‐14C]pectin‐labelled dietary plant cell walls in the rat

The metabolism and fate of [methyl‐14C] and [uronate‐6‐14C]pectin‐labelled dietary plant cell walls in the rat

Optimized Sample Handling Strategy for Metabolic Profiling of Human Feces

Effect of methanol intoxication on spcific immune functions of albino rats

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The metabolism and fate of [methyl‐¹⁴C] and [uronate‐6‐¹⁴C]pectin‐labelled dietary plant cell walls in the rat

The metabolism and fate of [methyl‐¹⁴C] and [uronate‐6‐¹⁴C]pectin‐labelled dietary plant cell walls in the rat