Evaluation of the impact of buffered peptone water composition on the discrimination between Salmonella enterica and Escherichia coli by Raman spectroscopy.

The detection of Salmonella spp. in food samples is regulated by the ISO 6579:2002 standard, which requires that precise procedures are followed to ensure the reliability of the detection process. This standard requires buffered peptone water as a rich medium for the enrichment of bacteria. However, the effects of different brands of buffered peptone water on the identification of microorganisms by Raman spectroscopy are unknown. In this regard, our study evaluated the discrimination between two bacterial species, Salmonella enterica and Escherichia coli, inoculated and analyzed with six of the most commonly used buffered peptone water brands. The results showed that bacterial cells behaved differently according to the brand used in terms of biomass production and the spectral fingerprint. The identification accuracy of the analyzed strains was between 85% and 100% depending on the given brand. Several batches of two brands were studied to evaluate the classification rates between the analyzed bacterial species. The chemical analysis performed on these brands showed that the nutrient content was slightly different and probably explained the observed effects. On the basis of these results, Raman spectroscopy operators are encouraged to select an adequate culture medium and continue its use throughout the identification process to guarantee optimal recognition of the microorganism of interest.

Potential of Raman Spectroscopy To Monitor Arsenic Toxicity on Bacteria: Insights toward Multiparametric Bioassays.

In the field of toxicological bioassays, the latest progress in Raman spectroscopy opens new research perspectives on a fast method of observing metabolic responses against toxic agents. This technique offers a multiparametric approach, providing an overview of the physiological changes that are caused by pollutants. However, physiological spectral fingerprints require complex chemometric methods for proper analysis. In this study, particular attention has been given to the elaboration of an "aberrant spectra" detection strategy to highlight the effects of arsenic on the bacteria Escherichia coli. This strategy significantly improved spectra classification, consistent with a dose-response effect of the four tested concentrations of the metal. Indeed, the correct classification score of the spectra increased from 88 to more than 99%. The exposure time effect has also been investigated. The fine analysis of Raman spectroscopy fingerprints enabled the design of different "spectral signatures", highlighting early and late effects of arsenic on bacteria. The observed variations are in agreement with the expected toxicity and encourage the use of Raman spectroscopy for toxic element detection.

Raman spectroscopy applied to the horizontal methods ISO 6579:2002 to identify Salmonella spp. in the food industry.

Food safety is a major concern for suppliers in the food chain to ensure the safety of their products. The identification procedure requested by norms is tedious, and it often requires systematic controls and qualified staff to perform the necessary analyses. Raman spectroscopy offers new opportunities to rapidly and efficiently ascertain the presence of pathogens in samples. Nevertheless, this technique requires a standardized procedure to be applied in the industrial context. Our study shows that the variability between spectral fingerprints is related to the physiological state of the microbial species and the growth phase of the bacteria plays a crucial role in its identification by Raman spectroscopy. To improve the discrimination between closely related bacterial species, a procedure based on the selection of bacterial spectra in the exponential growth phase was proposed. Different ways to introduce Raman spectroscopy in the ISO 6579:2002 standards are also proposed from the entire process to a shorter protocol. In the latter case, the identification of bacterial colonies after the selective enrichment step was proposed with the advantages of this path in terms of simplicity and rapidity (analysis time is reduced up to 50 h from the 100 h required by the standard). The protocol validated using six food categories from industrial partners have presented a good correlation by confirmation with other laboratory classical methods. In the future, this procedure could be introduced to the control system of the food production chain with a reliable database for various microorganisms encountered in this field.

A multiway chemometric and kinetic study for evaluating the thermal stability of edible oils by ¹H NMR analysis: comparison of methods.

The degradation process of edible oils of different nature, submitted to heating at 170°C, 190°C and 210°C with aeration, was studied by means of (1)H nuclear magnetic resonance spectroscopy (NMR). In this study, secondary products such as aldehydes were detected and monitored over time. Two complementary analytical approaches were adopted to characterize the kinetics of the appearance of aldehydes in the heated oils. This first was a classical kinetic approach based on the assumption that the overall degradation reaction to form aldehydes follows a rate law of order 1. This approach allowed us to calculate a thermal stability criterion for classifying the oils according to their heat stability. A second approach was to use the spectral fingerprint corresponding to aldehydes in a multivariate data analysis procedure in order to give the major trend in the studied phenomena, taking into account the multiway nature of recorded data. The application of different 3-way and 4-way Tucker3 models led to a better understanding of the chemical stability of the oils studied and was used to determine the order of stability of these oils. This multiway approach provides additional information that 2-way processing (PCA) does not provide clearly, such as the overall contribution of the heating time factor on the chemical evolution of oils. In conclusion, this work shows that a fully chemometric study of NMR spectra allows to order the oils according to their thermal stability and to achieve a result in good agreement with existing analytical and kinetic studies in the literature.

Quinine sulphate pellets for flexible pediatric drug dosing: formulation development and evaluation of taste-masking efficiency using the electronic tongue.

The purpose of this study was to develop a taste-masked quinine sulphate dosage form as a flexible pediatric formulation tool. Pellets were produced as they offer more flexibility to body weight dose adaptation and therefore represent an alternative to tablet breaking in pediatrics. Quinine sulphate pellets were produced via extrusion-spheronisation. Next pellets were coated using Eudragit E PO to obtain a taste-masked formulation. Using 15% dibutyl sebacate (based on polymer weight) as a plasticizer in the formulation caused rapid pellet agglomeration during storage at 40 degrees C and 75% relative humidity. Using stearic acid (15% based on polymer weight) as plasticizer yielded pellets which were less sensitive to sticking. Quinine sulphate release in water within the first 5 min of dissolution testing: 9.2%, 5.9% and 2.1% of the drug dose was released from pellets coated with 10%, 20% and 30% (w/w) Eudragit E PO, respectively. These observations correlated well with the bitterness score of the formulations determined via the Astree electronic tongue and its Bitterness Prediction Module, showing that 20% (w/w) Eudragit E PO was required to obtain a homogeneous film and to delay quinine sulphate release sufficiently to mask the bitterness after drug administration. In acid medium immediate quinine sulphate release was obtained.

The integrin, alpha6beta1, is necessary for the matrix-dependent activation of FAK and MAP kinase and the migration of human hepatocarcinoma cells.

Expression of the integrin, alpha6beta1, a receptor for laminins, is associated with the progression of hepatocellular carcinoma (HCC). The approach to investigating the alpha6beta1 integrin signaling in HCC cells was to express a deletion mutant of the beta4 integrin cytoplasmic domain (beta4-Deltacyt) in 2 HCC cell lines, HepG2 and Huh7. Expression of this mutant prevents formation of the alpha6beta1 heterodimer. As expected, adhesion of both the HepG2/beta4-Deltacyt and Huh7/beta4-Deltacyt transfectants to laminin, but not to collagen, was reduced compared with the mock transfectants. However, migration of the beta4-Deltacyt transfectants toward both collagen and laminin was inhibited, suggesting a role for alpha6beta1 in the signaling of migration. Migration of HCC cells requires mitogen-activated protein (MAP) kinase. The adhesion of the beta4-Deltacyt transfectants to collagen resulted in a substantial reduction in MAP kinase activation in comparison with the mock transfectants, although their ability to activate MAP kinase in response to epidermal growth factor (EGF) stimulation was not impaired. In addition, matrix adhesion of the beta4-Deltacyt transfectants did not stimulate the tyrosine phosphorylation of focal adhesion kinase (FAK), and this defect correlated with reduced binding of adaptor protein Grb2 to FAK. These results suggest that FAK tyrosine phosphorylation is dependent on alpha6beta1 expression, and that FAK-Grb2 association plays a central role in alpha6beta1-mediated activation of MAP kinase. Moreover, the expression of alpha6beta1 in HCC cells is necessary for FAK/MAP kinase-dependent migration.

Kiloh-Nevin syndrome: a clinical case of compression of the anterior interosseous nerve.

Anterior interosseous nerve syndrome is a rare occurrence. One particular case, in terms of its etiopathogenesis, and its clinical findings that involved isolated lesion of the long flexor muscle of the thumb is reported. Healing occurred after approximately 10 months. Medical and physiotherapeutic treatment were carried out.