The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David L Wetzel - One of the best experts on this subject based on the ideXlab platform.
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Phenotypic expression in wheat revealed using FT-IR Microspectroscopy
Vibrational Spectroscopy, 2010Co-Authors: Lauren R. Brewer, David L WetzelAbstract:Abstract Wheat selected for cultivation through the centuries has a glume that is “soft” instead of “tough” as naturally occurring. In production, this is desIRable because it enables mechanical threshing with efficient separation of kernel from the head of each stalk without damaging the kernel. FT-IR Microspectroscopy provides chemically based, objective assessment of genetic expression by measuring the extent of genetic expression. In the Microbeam Molecular Spectroscopy Laboratory, Manhattan, KS, an imaging FT-IR microspectrometer with a detector array focused on the image plane was used to obtain spectral data from dissected glume specimens of nine tough and eleven soft wheat cultivars in a rectangular mapping pattern. With cellulose as the substrate, the extent of lignification is measurable from the ratio of the lignin (1508 cm −1 ) baseline adjusted band area to the representative cellulosic (1370 cm −1 ) band area. A distinction between soft and tough glumes is obtained in numerical terms. Using a band ratio minimizes variation due to thickness differences. While analyzing mapped sections of glume, care is taken to avoid tabulation of spectral data from vascular bundles. Inclusion of these data would to avoid tabulation of spectral data from vascular bundles. Inclusion of these data would bias the analysis toward the composition of highly lignified vascular bundles. Spatially resolved focal plane array FT-IR Microspectroscopy reveals the extent of glume lignification that is coincident with the toughness trait. This enables breeders to rank the degree of lignin expression and discriminate between soft and tough breeding results.
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fourier transform infrared ft IR microspectroscopic census of single starch granules for octenyl succinate ester modification
Journal of Agricultural and Food Chemistry, 2009Co-Authors: David L WetzelAbstract:Fourier transform infrared (FT-IR) Microspectroscopy was used to investigate reaction homogeneity of octenyl succinic anhydride modification on waxy maize starch and detect uniformity of blends of modified and native starches. For the fIRst time, the level and uniformity of chemical substitution on individual starch granules were analyzed by FT-IR Microspectroscopy. More than 100 starch granules of each sample were analyzed one by one by FT-IR Microspectroscopy. In comparison to the native starch, modified starch had two additional bands at 1723 and 1563 cm−1, indicative of ester formation in the modified starch. For the 3% modification level, the degree of substitution (DS) was low (0.019) and the distribution of the ester group was not uniform among starch granules. For the modified starch with DS of 0.073, 99% of individual starch granules had a large carbonyl band area, indicating that most granules were modified to a sufficient extent that the presence of theIR carbonyl ester classified them individu...
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FT-IR Microspectroscopy Enhances Biological and Ecological Analysis of Algae
Applied Spectroscopy Reviews, 2009Co-Authors: Justin N. Murdock, David L WetzelAbstract:Abstract Fourier Transform Infrared (FT-IR) Microspectroscopy provides an in situ, nondestructive chemical analysis of individual algal cells. Algae play key roles in nutrient cycling and energy flow through aquatic ecosystems and are pivotal in the sequestration of inorganic nutrients (e.g., carbon, nitrogen, and phosphorus) and transformation into organic forms. However, most methods used to measure algal nutritional and physiological changes are limited to detecting whole community responses because of the relatively large quantity of material needed for analysis (i.e., milligrams to grams). The spatial resolution achievable with infrared Microspectroscopy allows for the analysis of macromolecular pools (e.g., proteins, lipids, carbohydrates) in individual cells that allows species specific measurements within heterogeneous microscopic communities. Initial applications characterized molecular pools within marine macroalgae and have since progressed toward ecologically based questions concerning algal p...
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Preparation of Soybean Seed Samples for FT-IR Microspectroscopy
Biotechnic & histochemistry : official publication of the Biological Stain Commission, 2005Co-Authors: Ln Pietrzak, David L WetzelAbstract:Typical preparation of seed samples for infrared (IR) Microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes...
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enhanced potential for metabolic studies using narrow band sensitized ft IR Microspectroscopy
Cellular and Molecular Biology, 2003Co-Authors: David L WetzelAbstract:The ability to detect and measure the relative concentration of deuterated substance found in tissue specimens is enhanced by adding a custom made-to-order 50 microm narrow MCT band that has an optimized response profile for the CD, ND and OH absorption bands. In the short range of interest it has a 2:1 signal advantage over the stock MCT detector and the steep cut off before the finger print region significantly diminishing the noise. The result is that levels of specific deuterated compounds experimentally administered to biological systems and dispersed by the host organism can be detected and measured The custom small target size narrow-band detector with increased signal and reduced noise enhances the potential for the use of FT-IR microspectoscopy as a novel way to study metabolism without the use of radioactive materials.
Maria Luiza S. Mello - One of the best experts on this subject based on the ideXlab platform.
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Topochemistry, optical anisotropy and FT-IR Microspectroscopy of the cocoon of Lithurgus chrysurus (Hymenoptera, Megachilidae)
Micron (Oxford England : 1993), 2016Co-Authors: Maria Luiza S. Mello, Benedicto De Campos Vidal, Eli Heber M. Dos Anjos, Jerome G. RozenAbstract:A previous study has not revealed the participation of a mucous component in the cocoon wall of the solitary bee, Lithurgus chrysurus, differing from the cocoon structure reported for many other bee species. However, uncertainty remains, because only the median and rear zones of this cocoon type have thus far been analyzed. Here, we studied the front zone of this cocoon, searching its components and theIR organization, to fill this knowledge gap. Topochemical assays, polarization microscopy and Fourier transform-infrared (FT-IR) Microspectroscopy were used to study cross sections from L. chrysurus cocoon. Three main layers differing in structural organization were found to compose the cocoon wall. Silk fibroins were assumed to constitute the filamentous threads of the inner and outer layers and the laminar structure of the intermediate layer. Deduced from its topochemical properties and FT-IR spectral signature, a foamy material containing mucin glycoproteins and carboxylated acid glycosaminoglycans was found in the intermediate layer. FT-IR analysis using a Savitzky-Golay 2nd-derivative and absence of linear dichroism and bIRefringence phenomena suggest that a random-coil secondary structure predominates in the foam component. Co-existence of α-helical and β-sheet conformations is also hypothesized for the fibroin component of this cocoon. It is thus concluded that in addition to fibroin elements, a mucous component, likely contributed by a Malpighian tubule secretion, integrates the composition of the front zone of the cocoon wall of L. chrysurus. In addition, the FT-IR analysis of the inner layer silk of this cocoon suggests significant differences in comparison to the silk fibroins of the silkworm, and some minor spectral differences in comparison to published data on the honeybee silk, with respect to protein secondary structure.
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FT-IR Microspectroscopy of Rat Ear Cartilage.
PloS one, 2016Co-Authors: Benedicto De Campos Vidal, Maria Luiza S. MelloAbstract:Rat ear cartilage was studied using Fourier transform-infrared (FT-IR) Microspectroscopy to expand the current knowledge which has been established for relatively more complex cartilage types. Comparison of the FT-IR spectra of the ear cartilage extracellular matrix (ECM) with published data on articular cartilage, collagen II and 4-chondroitin-sulfate standards, as well as of collagen type I-containing dermal collagen bundles (CBs) with collagen type II, was performed. Ear cartilage ECM glycosaminoglycans (GAGs) were revealed histochemically and as a reduction in ECM FT-IR spectral band heights (1140-820 cm-1) after testicular hyaluronidase digestion. Although ear cartilage is less complex than articular cartilage, it contains ECM components with a macromolecular orientation as revealed using polarization microscopy. Collagen type II and GAGs, which play a structural role in the stereo-arrangement of the ear cartilage, contribute to its FT-IR spectrum. Similar to articular cartilage, ear cartilage showed that proteoglycans add a contribution to the collagen amide I spectral region, a finding that does not recommend this region for collagen type II quantification purposes. In contrast to articular cartilage, the symmetric stretching vibration of -SO3- groups at 1064 cm-1 appeared under-represented in the FT-IR spectral profile of ear cartilage. Because the band corresponding to the asymmetric stretching vibration of -SO3- groups (1236-1225 cm-1) overlapped with that of amide III bands, it is not recommended for evaluation of the -SO3- contribution to the FT-IR spectrum of the ear cartilage ECM. Instead, a peak (or shoulder) at 1027-1016 cm-1 could be better considered for this intent. Amide I/amide II ratios as calculated here and data from the literature suggest that protein complexes of the ear cartilage ECM are arranged with a lower helical conformation compared to pure collagen II. The present results could motivate further studies on this tissue under pathological or experimental states involving ear cartilage.
Achim Kohler - One of the best experts on this subject based on the ideXlab platform.
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monitoring secondary structural changes in salted and smoked salmon muscle myofiber proteins by ft IR Microspectroscopy
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Izaskun Carton, Ulrike Bocker, Ragni Ofstad, Oddvin Sorheim, Achim KohlerAbstract:Fourier transform infrared (FT-IR) Microspectroscopy and light microscopy were used to study changes in the myofibrillar proteins and microstructure in salmon muscle due to dry salting and smoking. Light microscopy showed that the myofibers of the smoked samples were more shrunken and theIR shape more IRregular and edged than for the nonsmoked samples. FT-IR Microspectroscopy showed that salting time mostly contributed in the amide I region, revealing that secondary structural changes of proteins were primarily affected by salting. The main variation in the amide II region was caused by smoking. As it is known that smoke components can react with amino acid side chains and that the contribution of the side chain in the amide II region is larger than that in amide I, it is concluded that the observed differences are due to interactions between carbonyl compounds of smoke and amino acid side chains.
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FT‐IR Microspectroscopy: a promising method for the rapid identification of Listeria species
FEMS microbiology letters, 2007Co-Authors: Astrid Oust Janbu, Trond Møretrø, Dominique Bertrand, Achim KohlerAbstract:This work presents a pilot study to investigate the potential of fourier transform infrared (FT-IR) Microspectroscopy for rapid identification of Listeria at the species level. Using this technique, FT-IR spectra were acquIRed from 30 strains from five Listeria species. The FT-IR spectra were analysed using stepwise canonical discriminant analysis and partial least-squares regression in a stepwise identification scheme. The results showed that 93% of all the samples were assigned to the correct species, and that 80% of the Listeria monocytogenes strains were correctly identified. In comparison, 100% of the samples, including the L. monocytogenes samples, were correctly identified using spectra acquIRed by FT-IR macrospectroscopy. The results show that FT-IR Microspectroscopy has potential as a rapid screening method for Listeria, which is especially valuable for the food industry.
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Influence of aging and salting on protein secondary structures and water distribution in uncooked and cooked pork. A combined FT-IR Microspectroscopy and 1H NMR relaxometry study.
Journal of agricultural and food chemistry, 2006Co-Authors: Hanne Christine Bertram, Achim Kohler, Ulrike Bocker, Ragni Ofstad, Henrik J. AndersenAbstract:Fourier transform infrared (FT-IR) Microspectroscopy and low-field (LF) proton NMR transverse relaxation measurements were used to study the changes in protein secondary structure and water distrib...
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influence of aging and salting on protein secondary structures and water distribution in uncooked and cooked pork a combined ft IR Microspectroscopy and 1h nmr relaxometry study
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Hanne Christine Bertram, Achim Kohler, Ulrike Bocker, Ragni Ofstad, Henrik J. AndersenAbstract:Fourier transform infrared (FT-IR) Microspectroscopy and low-field (LF) proton NMR transverse relaxation measurements were used to study the changes in protein secondary structure and water distribution as a consequence of aging (1 day and 14 days) followed by salting (3%, 6%, and 9% NaCl) and cooking (65 degrees C). An enhanced water uptake and increased proton NMR relaxation times after salting were observed in aged meat (14 days) compared with nonaged meat (1 day). FT-IR bands revealed that salting induced an increase in native beta-sheet structure while aging triggered an increase in native alpha-helical structure before cooking, which could explain the effects of aging and salting on water distribution and water uptake. Moreover, the decrease in T2 relaxation times and loss of water upon cooking were attributed to an increase in aggregated beta-sheet structures and a simultaneous decrease in native protein structures. Finally, aging increased the cooking loss and subsequently decreased the final yield, which corresponded to a further decrease in T2 relaxation times in aged meat upon cooking. However, salting weakened the effect of aging on the final yield, which is consistent with the increased T2 relaxation times upon salting for aged meat after cooking and the weaker effect of aging on protein secondary structural changes for samples treated with high salt concentration. The present study reveals that changes in water distribution during aging, salting, and cooking are not only due to the accepted causal connection, i.e., proteolytic degradation of myofibrillar structures, change in electrostatic repulsion, and dissolution and denaturation of proteins, but also dynamic changes in specific protein secondary structures.
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Salt-induced changes in pork myofibrillar tissue investigated by FT-IR Microspectroscopy and light microscopy.
Journal of agricultural and food chemistry, 2006Co-Authors: Ulrike Bocker, Ragni Ofstad, Hanne Christine Bertram, Bjørg Egelandsdal, Achim KohlerAbstract:FT-IR Microspectroscopy and light microscopy were used to investigate pork muscle musculus semitendinosus samples, taken from three animals, that were subjected to brine salting at different concentrations (0.9, 3, 6, and 9% NaCl). Differences in spectral characteristics and in microstructure were observed in meat from animals differing in initial pH and varying salt concentrations. The FT-IR data displayed changes in the amide I region from 1700 to 1600 cm(-1). This spectral range was analyzed by principal component analysis (PCA) and partial least-squares regression (PLSR). These methods revealed correlations between the spectral data and the different animals, salt content, moisture content, pH value, and myofiber diameter. A shrinking share of alpha-helical components was related to an increase in salt concentration in the muscle. At the same time, a greater share in nonhydrogenated C=O groups (1668 cm(-1)) was related to an increase in salt concentration in the meat. The share of aggregated beta-strands differed with respect to the different animals but was not influenced by salt concentration. The meat at higher pHs (>6) had less aggregated beta-strands than that at lower pHs (5.6-5.7). It could be demonstrated that simultaneous with changes in microstructure, pH value, salt, and moisture content were alterations in the protein amide I region as measured by FT-IR Microspectroscopy, revealing a relationship between these biophysical and chemical parameters and secondary protein structure attributes.
Benedicto De Campos Vidal - One of the best experts on this subject based on the ideXlab platform.
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Topochemistry, optical anisotropy and FT-IR Microspectroscopy of the cocoon of Lithurgus chrysurus (Hymenoptera, Megachilidae)
Micron (Oxford England : 1993), 2016Co-Authors: Maria Luiza S. Mello, Benedicto De Campos Vidal, Eli Heber M. Dos Anjos, Jerome G. RozenAbstract:A previous study has not revealed the participation of a mucous component in the cocoon wall of the solitary bee, Lithurgus chrysurus, differing from the cocoon structure reported for many other bee species. However, uncertainty remains, because only the median and rear zones of this cocoon type have thus far been analyzed. Here, we studied the front zone of this cocoon, searching its components and theIR organization, to fill this knowledge gap. Topochemical assays, polarization microscopy and Fourier transform-infrared (FT-IR) Microspectroscopy were used to study cross sections from L. chrysurus cocoon. Three main layers differing in structural organization were found to compose the cocoon wall. Silk fibroins were assumed to constitute the filamentous threads of the inner and outer layers and the laminar structure of the intermediate layer. Deduced from its topochemical properties and FT-IR spectral signature, a foamy material containing mucin glycoproteins and carboxylated acid glycosaminoglycans was found in the intermediate layer. FT-IR analysis using a Savitzky-Golay 2nd-derivative and absence of linear dichroism and bIRefringence phenomena suggest that a random-coil secondary structure predominates in the foam component. Co-existence of α-helical and β-sheet conformations is also hypothesized for the fibroin component of this cocoon. It is thus concluded that in addition to fibroin elements, a mucous component, likely contributed by a Malpighian tubule secretion, integrates the composition of the front zone of the cocoon wall of L. chrysurus. In addition, the FT-IR analysis of the inner layer silk of this cocoon suggests significant differences in comparison to the silk fibroins of the silkworm, and some minor spectral differences in comparison to published data on the honeybee silk, with respect to protein secondary structure.
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FT-IR Microspectroscopy of Rat Ear Cartilage.
PloS one, 2016Co-Authors: Benedicto De Campos Vidal, Maria Luiza S. MelloAbstract:Rat ear cartilage was studied using Fourier transform-infrared (FT-IR) Microspectroscopy to expand the current knowledge which has been established for relatively more complex cartilage types. Comparison of the FT-IR spectra of the ear cartilage extracellular matrix (ECM) with published data on articular cartilage, collagen II and 4-chondroitin-sulfate standards, as well as of collagen type I-containing dermal collagen bundles (CBs) with collagen type II, was performed. Ear cartilage ECM glycosaminoglycans (GAGs) were revealed histochemically and as a reduction in ECM FT-IR spectral band heights (1140-820 cm-1) after testicular hyaluronidase digestion. Although ear cartilage is less complex than articular cartilage, it contains ECM components with a macromolecular orientation as revealed using polarization microscopy. Collagen type II and GAGs, which play a structural role in the stereo-arrangement of the ear cartilage, contribute to its FT-IR spectrum. Similar to articular cartilage, ear cartilage showed that proteoglycans add a contribution to the collagen amide I spectral region, a finding that does not recommend this region for collagen type II quantification purposes. In contrast to articular cartilage, the symmetric stretching vibration of -SO3- groups at 1064 cm-1 appeared under-represented in the FT-IR spectral profile of ear cartilage. Because the band corresponding to the asymmetric stretching vibration of -SO3- groups (1236-1225 cm-1) overlapped with that of amide III bands, it is not recommended for evaluation of the -SO3- contribution to the FT-IR spectrum of the ear cartilage ECM. Instead, a peak (or shoulder) at 1027-1016 cm-1 could be better considered for this intent. Amide I/amide II ratios as calculated here and data from the literature suggest that protein complexes of the ear cartilage ECM are arranged with a lower helical conformation compared to pure collagen II. The present results could motivate further studies on this tissue under pathological or experimental states involving ear cartilage.
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Fluorescence, aggregation properties and FT-IR Microspectroscopy of elastin and collagen fibers.
Acta histochemica, 2014Co-Authors: Benedicto De Campos VidalAbstract:Abstract Histological and histochemical observations support the hypothesis that collagen fibers can link to elastic fibers. However, the resulting organization of elastin and collagen type complexes and differences between these materials in terms of macromolecular orientation and frequencies of theIR chemical vibrational groups have not yet been solved. This study aimed to investigate the macromolecular organization of pure elastin, collagen type I and elastin–collagen complexes using polarized light DIC-microscopy. Additionally, differences and similarities between pure elastin and collagen bundles (CB) were investigated by Fourier transform-infrared (FT-IR) Microspectroscopy. Although elastin exhibited a faint bIRefringence, the elastin–collagen complex aggregates formed in solution exhibited a deep bIRefringence and formation of an ordered-supramolecular complex typical of collagen chIRal structure. The FT-IR study revealed elastin and CB peptide N H groups involved in different types of H-bonding. More energy is absorbed in the vibrational transitions corresponding to CH, CH2 and CH3 groups (probably associated with the hydrophobicity demonstrated by 8-anilino-1-naphtalene sulfonic acid sodium salt [ANS] fluorescence), and to νCN, δNH and ωCH2 groups of elastin compared to CB. It is assumed that the α-helix contribution to the pure elastin amide I profile is 46.8%, whereas that of the B-sheet is 20% and that unordered structures contribute to the remaining percentage. An FT-IR profile library reveals that the elastin signature within the 1360–1189 cm−1 spectral range resembles that of Conex–Toray aramid fibers.
Henrik J. Andersen - One of the best experts on this subject based on the ideXlab platform.
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Influence of aging and salting on protein secondary structures and water distribution in uncooked and cooked pork. A combined FT-IR Microspectroscopy and 1H NMR relaxometry study.
Journal of agricultural and food chemistry, 2006Co-Authors: Hanne Christine Bertram, Achim Kohler, Ulrike Bocker, Ragni Ofstad, Henrik J. AndersenAbstract:Fourier transform infrared (FT-IR) Microspectroscopy and low-field (LF) proton NMR transverse relaxation measurements were used to study the changes in protein secondary structure and water distrib...
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influence of aging and salting on protein secondary structures and water distribution in uncooked and cooked pork a combined ft IR Microspectroscopy and 1h nmr relaxometry study
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Hanne Christine Bertram, Achim Kohler, Ulrike Bocker, Ragni Ofstad, Henrik J. AndersenAbstract:Fourier transform infrared (FT-IR) Microspectroscopy and low-field (LF) proton NMR transverse relaxation measurements were used to study the changes in protein secondary structure and water distribution as a consequence of aging (1 day and 14 days) followed by salting (3%, 6%, and 9% NaCl) and cooking (65 degrees C). An enhanced water uptake and increased proton NMR relaxation times after salting were observed in aged meat (14 days) compared with nonaged meat (1 day). FT-IR bands revealed that salting induced an increase in native beta-sheet structure while aging triggered an increase in native alpha-helical structure before cooking, which could explain the effects of aging and salting on water distribution and water uptake. Moreover, the decrease in T2 relaxation times and loss of water upon cooking were attributed to an increase in aggregated beta-sheet structures and a simultaneous decrease in native protein structures. Finally, aging increased the cooking loss and subsequently decreased the final yield, which corresponded to a further decrease in T2 relaxation times in aged meat upon cooking. However, salting weakened the effect of aging on the final yield, which is consistent with the increased T2 relaxation times upon salting for aged meat after cooking and the weaker effect of aging on protein secondary structural changes for samples treated with high salt concentration. The present study reveals that changes in water distribution during aging, salting, and cooking are not only due to the accepted causal connection, i.e., proteolytic degradation of myofibrillar structures, change in electrostatic repulsion, and dissolution and denaturation of proteins, but also dynamic changes in specific protein secondary structures.
