Role of glycoside hydrolase genes in sinigrin degradation by E. coli O157:H7

Cordeiro, Roniele Peixoto; Doria, Juan H.; Zhanel, George G.; Sparling, Richard; Holley, Richard A.

doi:10.1016/j.ijfoodmicro.2015.04.008

Cited by 25 publications

(37 citation statements)

References 35 publications

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“…Further studies involved screening a variety of bacteria including E. coli 0157:H7 with sinigrin as a substrate with all strains producing allylisothiocyanate . More recent work with the GSL metabolizing E. coli 0157:H7 identified genes bglA and ascbB encoding 6‐phospho‐β‐glucosidases . Following gene disruption, the sinigrin degrading ability of this organism was substantially reduced.…”

Section: Introductionmentioning

confidence: 99%

“…Most interrogation of the bacterial genomes for identification of myrosinase genes has been based on plant myrosinase gene sequences. This was the case for the recent work with E. coli 0157:H7 where mutations of the putative myrosinase genes were generated by gene replacement to confirm the identify . We have used a similar approach where the candidate genes from E. casseliflavus CP1 and E. coli VL8 were cloned based on sequences from the known genomes of E. casseliflavus NCCP‐53 and E. coli O83:H1 NRG 857C and overexpressed them in E.coli although no myrosinase activity could be demonstrated.…”

Section: Introductionmentioning

confidence: 99%

“…Other recent work has identified a 6‐phospho‐β‐glucosidase ( bglA, ascbB, chbF ) which was based on homology with plant myrosinase. Gene mutations were carried out and analyzed for their ability to metabolize sinigrin and it was found that the genes bglA and ascbB played an important role in sinigrin degradation by E. coli 0157:H7 . It would be useful to express these genes and undertake detailed characterization to confirm their role as myrosinases.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Gut Glucosinolate Metabolism and Isothiocyanate Production

Narbad

Rossiter

2018

Molecular Nutrition Food Res

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The glucosinolate-myrosinase system in plants has been well studied over the years while relatively little research has been undertaken on the bacterial metabolism of glucosinolates. The products of myrosinase-based glucosinolate hydrolysis in the human gut are important to health, particularly the isothiocyanates, as they are shown to have anticancer properties as well as other beneficial roles in human health. This review is concerned with the bacterial metabolism of glucosinolates but is not restricted to the human gut. Isothiocyanate production and nitrile formation are discussed together with the mechanisms of the formation of these compounds. Side chain modification of the methylsulfinylalkyl glucosinolates is reviewed and the implications for bioactivity of the resultant products are also discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gut Glucosinolate Metabolism and Isothiocyanate Production

Narbad

Rossiter

2018

Molecular Nutrition Food Res

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“…These findings suggest that if hydrolysis to SFN by microbiota could be enhanced, consumers might obtain greater health benefits from cooked broccoli. Although microbial glycoside hydrolase has been shown to be involved in the degradation of GSL with the pathogenic Escherichia coli O157:H7 [16] and a soil Citrobacter spp. [17], it is not yet clear which gut commensal microorganism(s) are responsible for GSL conversion to ITC.…”

Section: Introductionmentioning

confidence: 99%

Dietary Broccoli Alters Rat Cecal Microbiota to Improve Glucoraphanin Hydrolysis to Bioactive Isothiocyanates

et al. 2017

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Broccoli consumption brings many health benefits, including reducing the risk of cancer and inflammatory diseases. The objectives of this study were to identify global alterations in the cecal microbiota composition using 16S rRNA sequencing analysis and glucoraphanin (GRP) hydrolysis to isothiocyanates ex vivo by the cecal microbiota, following different broccoli diets. Rats were randomized to consume AIN93G (control) or different broccoli diets; AIN93G plus cooked broccoli, a GRP-rich powder, raw broccoli, or myrosinase-treated cooked broccoli. Feeding raw or cooked broccoli for four days or longer both changed the cecal microbiota composition and caused a greater production of isothiocyanates ex vivo. A more than two-fold increase in NAD(P)H: quinone oxidoreductase 1 activity of the host colon mucosa after feeding cooked broccoli for seven days confirmed the positive health benefits. Further studies revealed that dietary GRP was specifically responsible for the increased microbial GRP hydrolysis ex vivo, whereas changes in the cecal microbial communities were attributed to other broccoli components. Interestingly, a three-day withdrawal from a raw broccoli diet reversed the increased microbial GRP hydrolysis ex vivo. Findings suggest that enhanced conversion of GRP to bioactive isothiocyanates by the cecal microbiota requires four or more days of broccoli consumption and is reversible.

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“…To date, identified bacterial glycosidases able to cleave the thio-linked sugar of glucosinolates include a glycoside hydrolase family 3 β-O-glucosidase in the soil-isolate Citrobacter WyE1 (Albaser et al, 2016); after determining that cell-free protein extract was capable of degrading glucosinolates, activity-guided purification was performed to isolate the active protein. A 6-phospho-βglucosidase was also determined to be associated with glucosinolate metabolism in the pathogenic E. coli strain 0157:H7, identified through homology to characterized plant myrosinases (Cordeiro et al, 2015); however, deletion of the homologous genes did not abolish the ability of the bacteria to hydrolyze the aliphatic GS sinigrin. While, to our knowledge, there have not been any reports to date of bacterial myrosinase-encoding genes that are both necessary and sufficient for GS hydrolysis, the sax operon in certain pathovars of the plant pathogen Pseudomonas syringae has been identified as being necessary and sufficient for overcoming aliphatic isothiocyanate toxicity (Fan et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

A metabolic pathway for glucosinolate activation by the human gut symbiontBacteroides thetaiotaomicron

Liou

Sirk

Diaz

et al. 2019

Preprint

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Diet is the largest source of plant-derived metabolites that influence human health. The gut microbiota can metabolize these molecules, altering their biological function. However, little is known about the gut bacterial pathways that process plant-derived molecules. Glucosinolates are well-known metabolites in brassica vegetables and metabolic precursors to cancer-preventive isothiocyanates. Here, we identify a genetic and biochemical basis for isothiocyanate formation by Bacteroides thetaiotaomicron, a prominent gut commensal species. Using a genome-wide transposon insertion screen, we identified an operon required for glucosinolate metabolism in B. thetaiotaomicron. Expression of BT2159-BT2156 in a non-metabolizing relative, Bacteroides fragilis, resulted in gain of glucosinolate metabolism. We show that isothiocyanate formation requires the action of BT2158 and either BT2156 or BT2157 in vitro. Monocolonization of mice with mutant BtΔ2157 showed reduced isothiocyanate production in the gastrointestinal tract. These data provide insight into the mechanisms by which a common gut bacterium processes an important dietary nutrient.with the induction of Nrf2, ITC have also been shown to interact with sensory and inflammatory pathways. Allyl ITC, derived from the GS sinigrin, is an agonist of the transient receptor potential ion channel TRPA1, which is involved in signaling inflammatory pain (Bellono et al., 2017), while sulforaphane has been shown to covalently modify lipopolysaccharide-activated Toll-like receptor 4 (TLR4), resulting in the reduced secretion of pro-inflammatory cytokines in human peripheral blood mononuclear cells and monocytes (Folkard et al., 2014).Plant and gut bacterial metabolism have been identified as two different routes for the conversion of GS into ITC products required for biological activity. Like many phytonutrients relevant to human health, GS in crucifers are involved in chemical defense in planta (Halkier and Gershenzon, 2006). These metabolites are stored in the plant tissue in an inert, pro-drug-like state and are converted into an active state by myrosinase enzymes, thio-specific glucoside hydrolases found in cruciferous vegetables (Figure 1A). GS are sequestered in vacuoles under normal conditions, while myrosinases are expressed in distinct, specialized myrosin cells (Kissen et al., 2009). Upon disruption of the plant tissue, myrosinases mediate the hydrolysis of GS into a variety of possible products, including ITC, nitriles, and epithionitriles, determined by environmental pH and the presence of specifier proteins.

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Role of glycoside hydrolase genes in sinigrin degradation by E. coli O157:H7

Cited by 25 publications

References 35 publications

Gut Glucosinolate Metabolism and Isothiocyanate Production

Gut Glucosinolate Metabolism and Isothiocyanate Production

Dietary Broccoli Alters Rat Cecal Microbiota to Improve Glucoraphanin Hydrolysis to Bioactive Isothiocyanates

A metabolic pathway for glucosinolate activation by the human gut symbiontBacteroides thetaiotaomicron

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