Optical probe for the analysis of trace indole in shrimp

Federico-Perez, Roberto A.; Chen, Xue-Tai

doi:10.1016/j.ab.2018.07.011

Cited by 7 publications

(8 citation statements)

References 29 publications

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“…The tryptophan broth was fermented with strains for 2 weeks, followed by the addition of Kovacs’ reagent (4‐Dimethylaminobenzaldehyde) to observe the color that developed on the surface of the broth to test for the production of indole derivatives ( Figure 1 a). [ 31 ]…”

Section: Resultsmentioning

confidence: 99%

Effect of Lactobacillus rhamnosus MN‐431 Producing Indole Derivatives on Complementary Feeding‐Induced Diarrhea Rat Pups Through the Enhancement of the Intestinal Barrier Function

Niu

Zhou

Gong

et al. 2021

Molecular Nutrition Food Res

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Scope Many infants suffer from complementary feeding‐induced diarrhea (CFID). Studies have shown that intestinal microbes can enhance the intestinal barrier and prevent diarrhea by producing indole derivatives that promote pregnane X receptor (PXR) expression. Methods and Results In this study, the indole test and determination of the PXR concentration are performed on tryptophan broth cultures of 320‐suspected Lactobacillus and Enterococcus strains. Four strains that produce indole derivatives that promote the expression of PXR are screened as potential functional probiotics. Both Lactobacillus rhamnosus MN‐431 (L. rhamnosus MN‐431) and Lactobacillus oris FN‐448 (L. oris FN‐448) can colonize the intestine of rat pups, and L. rhamnosus MN‐431 can significantly decrease the incidence of diarrhea and intestinal permeability in rat pups. Using real‐time qPCR and the analysis of the intestinal morphology using immunohistochemistry, it is observed that the metabolized tryptophan from L. rhamnosus MN‐431 can reduce small intestinal mucosal damage by stimulating PXR/NF‐κB signaling and activating PXR and aryl hydrocarbon receptor. The intestinal barrier is also enhanced by promoting the expression of tight junction proteins such as Occludin and zonula occludens‐1 in baby rats. Conclusion The results demonstrate that L. rhamnosus MN‐431 can metabolize tryptophan to prevent infantile CFID by promoting the expression of PXR.

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Section: Resultsmentioning

confidence: 99%

Effect of Lactobacillus rhamnosus MN‐431 Producing Indole Derivatives on Complementary Feeding‐Induced Diarrhea Rat Pups Through the Enhancement of the Intestinal Barrier Function

Niu

Zhou

Gong

et al. 2021

Molecular Nutrition Food Res

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“…Other potential applications of this new indole sensing principle include the assessment of seafood freshness (especially shrimp) and the indirect detection of L-abrine in foods and beverages. 37,38 Detection of Indole Using SNAP in the Solution Phase. Although sodium nitrite allows for rapid and sensitive detection of indole in a solution, it cannot be impregnated into a silicone rubber catheter due to its low solubility in organic solvents (e.g., tetrahydrofuran) that can swell silicone elastomers.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…coli detection kits in the field in place of Kovac’s reagent. Other potential applications of this new indole sensing principle include the assessment of seafood freshness (especially shrimp) and the indirect detection of l -abrine in foods and beverages. , …”

Section: Resultsmentioning

confidence: 99%

S-Nitrosothiol-Impregnated Silicone Catheter for Colorimetric Sensing of Indole and E. coli: Toward On-Body Detection of Urinary Tract Infections

Brady

Farooque

et al. 2022

ACS Sens.

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Although there are many techniques to detect pathogenic bacteria, most of them are only suited for in vitro diagnostics. We report a urinary catheter-based colorimetric sensor for potential on-body detection of E. coli, the most prevalent bacterial species in urinary tract infections associated with the use of urinary catheters. In urine, indole is secreted by E. coli and reacts with a nitrosating agent incorporated in a silicone catheter. A red dimeric product, indoxyl red, is generated within silicone rubber to allow for color-based indole sensing with high sensitivity, linearity, and specificity. This reaction is initiated by the nitrosation reaction of indole at its C-3 position via reagents like sodium nitrite or Snitroso-N-acetyl-penicillamine under aerobic conditions. The generated 3-nitrosoindole undergoes tautomerization, dimerization, and deoximation to form indoxyl red with high absorbance at 537 nm. In contrast to other indole sensors, the presented method can be applied in real catheters to detect indole and E. coli in biofluids such as urine. The is because (1) S-nitroso-N-acetyl-penicillamine, the nitrosating agent, can be impregnated into silicone elastomers, (2) indole from urine is extracted into silicone due to its hydrophobicity, and (3) the high acidity and oxygen solubility of silicone facilitates the sensing reaction within the silicone matrix. This silicone-based colorimetric sensor clearly differentiates E. coli below and above 10 5 CFU/mL, which is the threshold concentration of bacteriuria. We expect that early diagnosis of urinary tract infections using the naked eye is possible by functionalizing an exposed section of urinary catheters with the proposed molecular probe.

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“…Table S1 (Supporting Information) shows the simplicity of the developed PADs in the determination of indole in shrimp, compared with the method reported by Federico-Perez and Xue. 7 The PADs required a few steps with simple tools such as mortar, pestle, tea bag, and plastic bag to accomplish the extraction, while the analytical characteristics of the PADs have no significant differences in comparison with the Federico-Perez and Xue method.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Recent studies have demonstrated faster and cheaper methods that involve polymer membrane sensors for indole in gases and solutions. , Indole vapors are detected in concentrations ranging from 5 to 100 ppb in the gas phase using a polymer consisting of p -methoxybenzaldehyde and Nafion, although the work covered only the proof of principle. Conversely, Federico-Perez et al fabricated an indole sensor with an ethyl cellulose membrane to measure indole extracted with trichloroacetic acid and ice-cold petroleum ether.…”

mentioning

confidence: 99%

Dip-and-Read, Organic Solvent-Compatible, Paper-Based Analytical Devices Equipped with Chromatographic Separation for Indole Analysis in Shrimp

Seetasang

Kaneta

2022

ACS Sens.

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We developed an organic solvent-compatible paper-based analytical device (PAD) for the quantitative analysis of indole, which is an indicator of shrimp freshness. Although indole is insoluble in water, ethyl acetate is a suitable solvent to dissolve and extract indole from shrimp. The PADs are fabricated using a cutting method that allows the use of an organic solvent because no hydrophobic barrier is needed to form fluidic channels. Ehrlich’s reagent consists of 4-(dimethylamino)benzaldehyde and p-dimethylaminobenzaldehyde and was deposited onto the reaction zone of the PAD followed by lamination to prevent evaporation of the ethyl acetate. Samples are introduced into the PAD via immersion in organic sample solutions. When the PAD is immersed into an indole solution of ethyl acetate in a closed bottle, the sample solution penetrates the channel of the PAD and successively flows into the detection zone to form a hydrophilic colored product. The PADs provide a linear relationship between the logarithm of the indole concentration and the color intensity within a range of 1.0–20 ppm with correlation coefficients of r 2 > 0.99. The limits of detection and quantification are 0.36 and 0.71 ppm, respectively. Relative standard deviations for both the intraday (n = 2) and interday (n = 3) precision were less than 2.5%. In the indole analysis of shrimp, the PADs separated the interfering orange-colored astaxanthin in the extract from the colored product of indole via the paper chromatographic principle. We used the PADs to investigate the degradation of shrimp, and the results showed a rapid increase in the indole level after 7 days. High-performance liquid chromatography verified the accuracy of the PADs by showing good agreement with the obtained indole levels.

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Optical probe for the analysis of trace indole in shrimp

Cited by 7 publications

References 29 publications

Effect of Lactobacillus rhamnosus MN‐431 Producing Indole Derivatives on Complementary Feeding‐Induced Diarrhea Rat Pups Through the Enhancement of the Intestinal Barrier Function

Effect of Lactobacillus rhamnosus MN‐431 Producing Indole Derivatives on Complementary Feeding‐Induced Diarrhea Rat Pups Through the Enhancement of the Intestinal Barrier Function

S-Nitrosothiol-Impregnated Silicone Catheter for Colorimetric Sensing of Indole and E. coli: Toward On-Body Detection of Urinary Tract Infections

Dip-and-Read, Organic Solvent-Compatible, Paper-Based Analytical Devices Equipped with Chromatographic Separation for Indole Analysis in Shrimp

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