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Berlin Brandenburg

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  • 1
    Language: English
    In: Chemical Society reviews, 07 April 2016, Vol.45(7), pp.1999
    Description: Correction for 'The importance of hydration and DNA conformation in interpreting infrared spectra of cells and tissues' by Bayden R. Wood et al., Chem. Soc. Rev., 2015, DOI: .
    Keywords: Hydration ; Infrared Spectra ; Deoxyribonucleic Acid ; Miscellaneous Sciences (So) ; Analysis (MD) ; Chemical Analysis (Ep) ; Chemical Analysis (Ed) ; Chemical Analysis (EC) ; Components and Materials (General) (Ea);
    ISSN: 03060012
    E-ISSN: 1460-4744
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  • 2
    In: Physical Chemistry Chemical Physics, 2015, Vol.17(33), pp.21164-21168
    Description: Surface enhanced Raman scattering (SERS) is a powerful tool with great potential to provide improved bio-sensing capabilities. The current gold-standard method for diagnosis of malaria involves visual inspection of blood smears using light microscopy, which is time consuming and can prevent early diagnosis of the disease. We present a novel surface-enhanced Raman spectroscopy substrate based on gold-coated butterfly wings, which enabled detection of malarial hemozoin pigment within lysed blood samples containing 0.005% and 0.0005% infected red blood cells.
    Keywords: Spectrum Analysis, Raman ; Malaria -- Diagnosis ; Nanostructures -- Chemistry ; Plasmodium -- Isolation & Purification ; Wings, Animal -- Chemistry;
    ISSN: 1463-9076
    E-ISSN: 1463-9084
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  • 3
    Language: English
    In: Angewandte Chemie International Edition, 03 January 2014, Vol.53(1), pp.169-172
    Description: DNA double strand breaks (DSBs) are deadly lesions that can lead to genetic defects and cell apoptosis. Techniques that directly detect DNA DSBs include scanning electron microscopy, atomic force microscopy (AFM), and fluorescence based approaches. While these techniques can be used to identify DSBs they provide no information on the molecular events occurring at the break. Tip‐enhanced Raman scattering (TERS) can provide molecular information from DNA at the nanoscale and in combination with AFM provides a new way to visualize and characterize the molecular structure of DSBs. DSBs result from cleavage at the 3’‐ and 5’‐bonds of deoxyribose upon exposure to UVC radiation based on the observation of POH and methyl/methylene deformation modes enhanced in the TERS spectra. It is hypothesized that strand fragments are hydrogen‐terminated at the lesion, indicating the action of free radicals during photon exposure. (DSBs) were first detected and located by atomic force microscopy, and the molecular structure of this damage was characterized with tip‐enhanced Raman scattering (see picture) using a top‐down configuration and a reflective substrate. The first experimental evidence is reported confirming that individual DSBs result from cleavage at the 3′‐ and 5′‐bonds of deoxyribose upon exposure to ultraviolet C radiation.
    Keywords: Atomic Force Microscopy ; Dna Damage ; Double Strand Breaks ; Tip‐Enhanced Raman Scattering
    ISSN: 1433-7851
    E-ISSN: 1521-3773
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  • 4
    Language: English
    In: Journal of agricultural and food chemistry, 01 March 2017, Vol.65(8), pp.1724-1731
    Description: Microencapsulation protects cells against environmental stress encountered during the production of probiotics, which are used as live microbial food ingredients. Freeze-drying and spray-drying are used in the preparation of powdered microencapsulated probiotics. This study examines the ability of Fourier transform infrared (FTIR) spectroscopy to detect differences in cells exposed to freeze-drying and spray-drying of encapsulated Lactobacillus rhamnosus GG cells. The FTIR analysis clearly demonstrated there were more significant molecular changes in lipid, fatty acid content, protein, and DNA conformation of nonencapsulated compared to encapsulated bacterial cells. The technique was also able to differentiate between spray-dried and freeze-dried cells. The results also revealed the extent of protection from a protein-carbohydrate-based encapsulant matrix on the cells depending on the type drying process. The extent of this protection to the dehydration stress was shown to be less in spray-dried cells than in freeze-dried cells. This suggests that FTIR could be used as a rapid, noninvasive, and real-time measurement technique to detect detrimental drying effects on cells.
    Keywords: Fourier Transform Infrared Spectroscopy ; Freeze-Drying ; Microencapsulation ; Probiotics ; Spray-Drying ; Bacterial Proteins -- Chemistry ; DNA, Bacterial -- Chemistry ; Lactobacillus Rhamnosus -- Chemistry ; Probiotics -- Chemistry ; Spectroscopy, Fourier Transform Infrared -- Methods
    ISSN: 00218561
    E-ISSN: 1520-5118
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  • 5
    Language: English
    In: Journal of agricultural and food chemistry, 31 July 2013, Vol.61(30), pp.7234-41
    Description: Synchrotron-based infrared (IR) microspectroscopy is able to reveal structural features of biomaterials within intact tissue at both cellular and molecular levels. Heat-related treatments have been used to improve nutrient availability of canola seeds and meal. However, hitherto, there has been no study on the sensitivity and response of each layer in canola seeds to heat-related treatments. It is not known which layer (epiderm/mucllage, spermoderm, endosperm, or cotyledon) is the most sensitive to heat when heat treatment is applied to the seeds. Traditional wet chemical analysis is unable to answer such questions. The objective of this study is to use synchrotron IR microspectroscopy with multivariate molecular spectral analyses as a research tool to study heat treatment effects in a fast way on the structural changes in cotyledon tissues of yellow-type canola (Brassica) seeds among raw (treatment code "A"), wet heating (autoclaving at 121 °C for 60 min, treatment code "B"), and dry heating (dry roasting at 120 °C for 60 min, treatment code "C"). The hypothesis of this study was that different heat treatments have different heat penetration abilities on cotyledon tissues in yellow-type canola seeds. The multivariate analytical tools principal component analysis (PCA) and agglomerative hierarchal cluster analysis (AHCA) were applied to investigate variance and groupings within the spectral data set [whole spectral range of ca. 4000-650 cm(-1), spectral range of ca. 1300-900 cm(-1) (cellulose or saccarides), spectral range of ca. 1800-1500 cm(-1) (secondary structures of protein) and spectral range of ca. 1500-1300 cm(-1) (bending motion of methylene and methyl group; this change is consistent with the change in the range of ca. 3000-2800 cm(-1))]. The results showed that there were no clear cluster and groups formed in the cotyledon tissues among the three treatments (A, B, and C). There were no clear distinguished responses of the cotyledon tissues to different types of heat treatments using multivariate molecular spectral analyses. The results indicate that the cotyledon tissues might not be sufficiently penetrated by both heat treatments (autoclaving and dry roasting) under the specified conditions. A future study is needed to analyze individual functional group band intensity among the treatments using univariate molecular spectral analysis to confirm multivariate PCA and cluster analyses.
    Keywords: Animal Feed -- Analysis ; Brassica -- Chemistry ; Cooking -- Methods ; Cotyledon -- Chemistry ; Seeds -- Chemistry ; Spectrophotometry, Infrared -- Methods
    ISSN: 00218561
    E-ISSN: 1520-5118
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  • 6
    Language: English
    In: Nano letters, 14 March 2012, Vol.12(3), pp.1555-60
    Description: Hemoglobin nanocrystals were analyzed with tip-enhanced Raman scattering (TERS), surface-enhanced resonance Raman scattering (SERRS) and conventional resonance Raman scattering (RRS) using 532 nm excitation. The extremely high spatial resolution of TERS enables selective enhancement of heme, protein, and amino acid bands from the crystal surface not observed in the SERRS or RRS spectra. Two bands appearing at 1378 and 1355 cm(-1) assigned to the ferric and ferrous oxidation state marker bands, respectively, were observed in both TERS and SERRS spectra but not in the RRS spectrum of the bulk sample. The results indicate that nanoscale oxidation changes are occurring at the hemoglobin crystal surface. These changes could be explained by oxygen exchange at the crystal surface and demonstrate the potential of the TERS technique to obtain structural information not possible with conventional Raman microscopy.
    Keywords: Hemoglobins -- Chemistry ; Nanostructures -- Chemistry ; Spectrum Analysis, Raman -- Instrumentation
    ISSN: 15306984
    E-ISSN: 1530-6992
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  • 7
    Language: English
    In: Biophysical Journal, 28 January 2014, Vol.106(2), pp.206a-206a
    Keywords: Biology
    ISSN: 0006-3495
    E-ISSN: 1542-0086
    Source: ScienceDirect Journals (Elsevier)
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  • 8
    Language: English
    In: Analytica Chimica Acta, 29 November 2018, Vol.1033, pp.156-164
    Description: Infrared (IR) imaging is an emerging and powerful approach for studying the molecular composition of cells and tissues. It is a non-destructive and phenotypic technique which combines label-free molecular specific information from cells and tissues provided by IR with spatial resolution, offering great potential in biochemical and biomedical research and routine applications. The application of multivariate discriminant analysis using bilinear models such as Partial Least Squares-Discriminant Analysis (PLS-DA) to IR images requires to unfold the spatial directions in a two-way matrix, resulting in a loss of spatial information and structure. In this article, first we evidence that internal validation methods such as repeated -fold cross-validation (CV) can be overly optimistic when the pixel size of the image is lower than the lateral spatial resolution. Secondly, we propose a new approach for the unbiased internal evaluation of the model performance named COnstrained Repeated Random Subsampling–Cross Validation (CORRS-CV). This method is based on the generation of training and test sub-sets using a constrained random sampling of training pixels without replacement and it circumvents overly optimistic effects due to oversampling, providing more accurate and robust images. The approach can be applied in IR microscopy for the development of discriminant models to analyse underlying biochemical differences associated to anatomical and histopathological features in cells and tissues.
    Keywords: Infrared Hyperspectral Imaging ; Constrained Repeated Random Sampling - Cross Validation ; Partial Least Squares-Discriminant Analysis ; Oversampling ; Cross Validation ; Chemistry
    ISSN: 0003-2670
    E-ISSN: 1873-4324
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  • 9
    In: Chemical Society Reviews, 2016, Vol.45(7), pp.1980-1998
    Description: Since Watson and Crick's historical papers on the structure and function of DNA based on Rosalind Franklin's and Maurice Wilkin's X-ray diffraction patterns tremendous scientific curiosity has been aroused by the unique and dynamic structure of the molecule of life. A-DNA and B-DNA represent different conformations of the DNA molecule, which is stabilised by hydrogen interactions between base pairs, stacking interactions between neighboring bases and long-range intra- and inter-backbone forces. This review highlights the contribution Fourier transform infrared (FTIR) spectroscopy has made to the understanding of DNA conformation in relation to hydration and its potential role in clinical diagnostics. The review will first begin by elucidating the main forms of DNA conformation found in nature and the general structures of the A, B and Z forms. This is followed by a detailed critique on infrared spectroscopy applied to DNA conformation highlighting pivotal studies on isolated DNA, polynucleotides, nucleoprotein and nucleohistone complexes. A discussion on the potential of diagnosing cancer using FTIR spectroscopy based on the detection of DNA bands in cells and tissues will ensue, highlighting the recent studies investigating the conformation of DNA in hydrated and dehydrated cells. The method of hydration as a way to facilitate DNA conformational band assignment will be discussed and the conformational change to the A-form upon dehydration will be used to explain the reason for the apparent lack of FTIR DNA signals observed in fixed or air-dried cells and tissues. The advantages of investigating B-DNA in the hydrated state, as opposed to A-DNA in the dehydrated state, are exemplified in a series of studies that show: (1) improved quantification of DNA in cells; (2) improved discrimination and reproducibility of FTIR spectra recorded of cells progressing through the cell cycle; (3) insights into the biological significance of A-DNA as evidenced by an interesting study on bacteria, which can survive desiccation and at the same time undergo the BAB transition. Finally, the importance of preserving the B-DNA conformation for the diagnosis of cancer is put forward as way to improve the sensitivity of this powerful technique.
    Keywords: Molecular Structure ; Hydration ; Infrared Spectroscopy ; Bacteria ; Fourier Transforms ; Deoxyribonucleic Acid ; Cancer ; Dehydration ; Miscellaneous Sciences (So) ; Analysis (MD) ; Chemical Analysis (Ep) ; Chemical Analysis (Ed) ; Chemical Analysis (EC) ; Components and Materials (General) (Ea);
    ISSN: 0306-0012
    E-ISSN: 1460-4744
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  • 10
    Language: English
    In: Angewandte Chemie International Edition, 09 July 2018, Vol.57(28), pp.8519-8524
    Description: The aggregation pathways of neurodegenerative peptides determine the disease etiology, and their better understanding can lead to strategies for early disease treatment. Previous research has allowed modelling of hypothetic aggregation pathways. However, their direct experimental observation has been elusive owing to methodological limitations. Herein, we demonstrate that nanoscale chemical mapping by tip‐enhanced Raman spectroscopy of single amyloid fibrils at various stages of aggregation captures the fibril formation process. We identify changes in TERS/Raman marker bands for Aβ, including the amide III band (above 1255 cm for turns/random coil and below 1255 cm for β‐sheet conformation). The spatial distribution of β‐sheets in aggregates is determined, allowing verification of a particular fibrillogenesis pathway, starting from aggregation of monomers to ‐stable oligomers, which then rearrange to ordered β‐sheets, already at the oligomeric or protofibrillar stage. : Tip‐enhanced Raman spectroscopy of single amyloid‐β fibrils at various stages of aggregation captures the fibril formation process. The spatial distribution of β‐sheets in aggregates was determined based on amide III band position, allowing verification of a fibrillogenesis pathway, from aggregation of monomers to metastable oligomers, which then rearrange into ordered β‐sheets, already at the oligomeric or protofibrillar stage.
    Keywords: Alzheimer'S Disease ; Protein Aggregation Pathway ; Secondary Structure ; Tip-Enhanced Raman Spectroscopy ; Β-Amyloid
    ISSN: 1433-7851
    E-ISSN: 1521-3773
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