scholarly journals Characterization of polysaccharides from Eremurus hissaricus roots by FTIR spectroscopy

Author(s):  
A. I. Ashurov ◽  
A. S. Dzhonmurodov ◽  
S. R. Usmanova ◽  
Sh. E. Kholov ◽  
Z. M. Muhidinov

The structure of water'soluble gluco' and galactomannans (GlcMan and GalMan) isolated from the roots of several Eremurus'related plant species has been studied previously. This article characterizes polysaccharides and other extraction products from the root tubers of Eremurus hissaricus by Fourier' transform infrared (FTIR) spectroscopy using an attenuated total reflectance (ATR) accessory. Polysaccharide samples were purified from protein substances with the Sevage method and discoloured through a polyamide column. In the FTIR spectra, the main peaks attributed to asymmetric and symmetric stretching vibrations of CH2 of the pyranose ring (for GluMan - 2886, 1373, 1244 cm-1; for GalGluMan - 2923, 1370, 1238 cm-1) were enhanced by purification after removing bound protein impurities. The KnownitAll and IR-Pal 2 software applications were used to examine the spectra of a sample of purified GalGluMan in the studied polysaccharides. The results show that the intensity of the absorption maximum decreased at 1732 cm-1. At the same time, at 1552.92 cm-1, a new band appeared that refers to the valence vibrations of carboxyl (CO) or nitroso (NO) groups in the purified polysaccharide. This band appeared as a result of the Maillard reaction between the protein and the reducing end of the polysaccharide unit. The intensity of the bands in the 1238-1244 cm-1 region also decreased in the purified samples, which may be due to the elimination of a small fraction of protein. The use of FTIR spectroscopy allows the process of purifying watersoluble GluMan and acid-soluble polysaccharide of GalGluMan from acrylamide impurities to be characterized timely and accurately. Additionally, this method allows a comparative estimation of functional groups in polysaccharides of the root tubers of E. hissaricus.

2021 ◽  
pp. 002580242110109
Author(s):  
Sweety Sharma ◽  
Rito Chophi ◽  
Jaskirandeep Kaur Jossan ◽  
Rajinder Singh

The most important task in a criminal investigation is to detect and identify the recovered biological stains beyond reasonable scientific doubt and preserve the sample for further DNA analysis. In the light of this fact, many presumptive and confirmatory tests are routinely employed in the forensic laboratories to determine the type of body fluid. However, the currently used techniques are specific to one type of body fluid and hence it cannot be utilized to differentiate multiple body fluids. Moreover, these tests consume the samples in due process, and thus it becomes a great limitation especially considering the fact that samples are recovered in minute quantity in forensic cases. Therefore, such limitations necessitate the use of non-destructive techniques that can be applied simultaneously to all types of bodily fluids and allow sample preservation for further analysis. In the current work, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy has been used to circumvent the aforementioned limitations. The important factors which could influence the detection of blood such as the effect of substrates, washing/chemical treatment, ageing, and dilution limits on the analysis of blood have been analysed. In addition, blood discrimination from non-blood substance (biological and non-biological in nature) has also been studied. Chemometric technique that is PCA–LDA has been used to discriminate blood from other body fluids and it resulted in 100% accurate classification. Furthermore, blood and non-blood substances including fake blood have also been classified into separate clusters with a 100% accuracy, sensitivity, and specificity. All-inclusive, this preliminary study substantiates the potential application of ATR-FTIR spectroscopy for the non-destructive identification of blood traces in simulated forensic casework conditions with 0% rate of false classification.


2019 ◽  
Vol 57 (5) ◽  
Author(s):  
Lisa M. T. Lam ◽  
Philippe J. Dufresne ◽  
Jean Longtin ◽  
Jacqueline Sedman ◽  
Ashraf A. Ismail

ABSTRACT Invasive fungal infections by opportunistic yeasts have increased concomitantly with the growth of an immunocompromised patient population. Misidentification of yeasts can lead to inappropriate antifungal treatment and complications. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy is a promising method for rapid and accurate identification of microorganisms. ATR-FTIR spectroscopy is a standalone, inexpensive, reagent-free technique that provides results within minutes after initial culture. In this study, a comprehensive spectral reference database of 65 clinically relevant yeast species was constructed and tested prospectively on spectra recorded (from colonies taken from culture plates) for 318 routine yeasts isolated from various body fluids and specimens received from 38 microbiology laboratories over a 4-month period in our clinical laboratory. ATR-FTIR spectroscopy attained comparable identification performance with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). In a preliminary validation of the ATR-FTIR method, correct identification rates of 100% and 95.6% at the genus and species levels, respectively, were achieved, with 3.5% unidentified and 0.9% misidentified. By expanding the number of spectra in the spectral reference database for species for which isolates could not be identified or had been misidentified, we were able to improve identification at the species level to 99.7%. Thus, ATR-FTIR spectroscopy provides a new standalone method that can rival MALDI-TOF MS for the accurate identification of a broad range of medically important yeasts. The simplicity of the ATR-FTIR spectroscopy workflow favors its use in clinical laboratories for timely and low-cost identification of life-threatening yeast strains for appropriate treatment.


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