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1. Recent advancements of EC-QCL based mid-IR transmission spectroscopy of proteins and application to analysis of bovine milk

Author

Schwaighofer, A, Alcaraz, MR, Kuligowski, J, and Lendl, B

Subjects
PROTEIN SECONDARY STRUCTURE, IR SPECTROSCOPY, MILK ANALYSIS, Ciencias Químicas, Química Analítica, QUANTUM CASCADE LASER, CIENCIAS NATURALES Y EXACTAS
Abstract

Background:High emission powers of external cavity-quantum cascade laser (EC-QCL) light sources allow to employ significantly larger path lengths for infrared (IR) transmission measurements compared to conventional Fourier-transform infrared (FTIR) measurements employing thermal emitters. Objective:An EC-QCL based IR transmission setup is presented as a viable alternative for analysis of proteins in both, academic protein structure studies as well as in process analytical applications. Here, the application of EC-QCL based IR transmission spectroscopy is introduced for i) monitoring of the protein secondary structure and ii) rapid screening of the thermal history of commercial milk samples without prior sample preparation. Methods:Proteins present in milk were measured by QCL-IR and FTIR spectroscopy and spectra were compared. Dynamic conformational changes were followed by QCL-IR spectroscopy after chemical denaturation. Sixteen commercial milk samples were surveyed by QCL-IR spectroscopy and classified according to the experienced heat load during processing. Results:The 4?5 times higher applicable transmission path length (38 μm for QCL vs. 8 μm for FTIR measurements) allows robust measurements of the protein amide I band in aqueous solutions. It was shown that IR spectra of the protein amide I band acquired by EC-QCL transmission spectroscopy are comparable to FTIR spectra and the acquired spectra were employed for the study of conformational changes in protein standard solutions. Furthermore, a classification analysis of commercial bovine milk samples based on their thermal history was accomplished. Conclusions:The potential application of EC-QCL IR spectroscopy was demonstrated as a tool for following conformational changes of the secondary protein structure as well as for fast screening for estimating the heat load applied to commercial milk. Fil: Schwaighofer, Andreas. Technische Universitat Wien; Austria Fil: Alcaraz, Mirta Raquel. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Química. Cátedra de Química Analítica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Kuligowski, Julia. Health Research Institute La Fe; España. University Of Natural Resources And Life Sciences; Austria Fil: Lendl, Bernhard. Technische Universitat Wien; Austria

Published
2018

2. Mammary gland development in male rats perinatally exposed to propiconazole, glyphosate, or their mixture.

Author

Gomez AL, Altamirano GA, Alcaraz MR, Montemurro M, Schierano-Marotti G, Oddi SL, Culzoni MJ, Muñoz-de-Toro M, Bosquiazzo VL, and Kass L

Subjects
Pregnancy, Female, Rats, Animals, Male, Humans, Glycine toxicity, Glycine metabolism, Hyperplasia metabolism, Mammary Glands, Animal, Glyphosate, Triazoles toxicity, Prenatal Exposure Delayed Effects chemically induced, Prenatal Exposure Delayed Effects metabolism
Abstract

This study aimed to assess whether perinatal exposure to propiconazole (PRO), glyphosate (GLY) or their mixture (PROGLY) alters key endocrine pathways and the development of the male rat mammary gland. To this end, pregnant rats were orally exposed to vehicle, PRO, GLY, or a mixture of PRO and GLY from gestation day 9 until weaning. Male offspring were euthanized on postnatal day (PND) 21 and PND60. On PND21, GLY-exposed rats showed reduced mammary epithelial cell proliferation, whereas PRO-exposed ones showed increased ductal p-Erk1/2 expression without histomorphological alterations. On PND60, GLY-exposed rats showed reduced mammary gland area and estrogen receptor alpha expression and increased aromatase expression, whereas PRO-exposed ones showed enhanced lobuloalveolar development and increased lobular hyperplasia. However, PROGLY did not modify any of the endpoints evaluated. In summary, PRO and GLY modified the expression of key molecules and the development of the male mammary gland individually but not together., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Published
2023
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3. Chromatographic Applications in the Multi-Way Calibration Field.

Author

Chiappini FA, Alcaraz MR, Escandar GM, Goicoechea HC, and Olivieri AC

Abstract

In this review, recent advances and applications using multi-way calibration protocols based on the processing of multi-dimensional chromatographic data are discussed. We first describe the various modes in which multi-way chromatographic data sets can be generated, including some important characteristics that should be taken into account for the selection of an adequate data processing model. We then discuss the different manners in which the collected instrumental data can be arranged, and the most usually applied models and algorithms for the decomposition of the data arrays. The latter activity leads to the estimation of surrogate variables (scores), useful for analyte quantitation in the presence of uncalibrated interferences, achieving the second-order advantage. Recent experimental reports based on multi-way liquid and gas chromatographic data are then reviewed. Finally, analytical figures of merit that should always accompany quantitative calibration reports are described.

Published
2021
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