Fluorescence spectroscopy for rapid detection and classification of bacterial pathogens.

This study deals with the rapid detection and differentiation of Escherichia coli, Salmonella, and Campylobacter, which are the most commonly identified commensal and pathogenic bacteria in foods, using fluorescence spectroscopy and multivariate analysis. Each bacterial sample cultured under controlled conditions was diluted in physiologic saline for analysis. Fluorescence spectra were collected over a range of 200-700 nm with 0.

Novel search algorithms for a mid-infrared spectral library of cotton contaminants.

During harvest, a variety of plant based contaminants are collected along with cotton lint. The USDA previously created a mid-infrared, attenuated total reflection (ATR), Fourier transform infrared (FT-IR) spectral library of cotton contaminants for contaminant identification as the contaminants have negative impacts on yarn quality. This library has shown impressive identification rates for extremely similar cellulose based contaminants in cases where the library was representative of the samples searched.

Preparation of interesterified plastic fats from fats and oils free of trans fatty acid.

Interesterified plastic fats were produced with trans-free substrates of fully hydrogenated soybean oil, extra virgin olive oil, and palm stearin in a weight ratio of 10:20:70, 10:40:50, and 10:50:40, respectively, by lipase catalysis. The major fatty acids of the products were palmitic (32.2-47.

Near-infrared analysis of whole kernel barley: comparison of three spectrometers.

This study was conducted to develop calibration models for determining quality parameters of whole kernel barley using a rapid and nondestructive near-infrared (NIR) spectroscopic method. Two hundred and five samples of whole barley grains of three winter-habit types (hulled, malt, and hull-less) produced over three growing seasons and from various locations in the United States were used in this study. Among these samples, 137 were used for calibration and 68 for validation.

Near-infrared analysis of ground barley for use as a feedstock for fuel ethanol production.

The objective of this study was to explore the potential of near-infrared spectroscopy for determining the compositional quality properties of barley as a feedstock for fuel ethanol production and to compare the prediction accuracy between calibration models obtained using a Fourier transform near-infrared system (FT-NIR) and a dispersive near-infrared system. The total sample set contained 206 samples of three types of barley, hull-less, malt, and hulled varieties, which were grown at various locations in the eastern U.S.

The PARVUS gene is expressed in cells undergoing secondary wall thickening and is essential for glucuronoxylan biosynthesis.

Xylan, cellulose and lignin are the three major components of secondary walls in wood, and elucidation of the biosynthetic pathway of xylan is of importance for potential modification of secondary wall composition to produce wood with improved properties. So far, three Arabidopsis glycosyltransferases, FRAGILE FIBER8, IRREGULAR XYLEM8 and IRREGULAR XYLEM9, have been implicated in glucuronoxylan (GX) biosynthesis. In this study, we demonstrate that PARVUS, which is a member of family GT8, is required for the biosynthesis of the tetrasaccharide primer sequence, beta-D-Xyl-(1 --> 3)-alpha-l-Rha-(1 --> 2)-alpha-D-GalA-(1 --> 4)-D-Xyl, located at the reducing end of GX.

ATR-Fourier transform mid-infrared spectroscopy for determination of trans fatty acids in ground cereal products without oil extraction.

Fourier transform mid-infrared (FT-IR) spectroscopy was investigated as a method of analysis for trans fatty acid content of cereal products without the need for prior oil extraction. Spectra were obtained, with an FT-IR spectrometer equipped with an attenuated total reflectance (ATR) device, of ground samples pressed onto the diamond ATR surface, and trans fatty acids were measured by a modification of AOAC Method 996.01.

Transfer of near-infrared calibration model for determining fiber content in flax: effects of transfer samples and standardization procedure.

The transfer of a calibration model for determining fiber content in flax stem was accomplished between two near-infrared spectrometers, which are the same brand but which require a standardization. In this paper, three factors, including transfer sample set, spectral type, and standardization method, were investigated to obtain the best standardization result. Twelve standardization files were produced from two sets of the transfer sample (sealed reference standards and a subset of the prediction set), two types of the transfer sample spectra (raw and preprocessed spectra), and three standardization methods (direct standardization (DS), piecewise direct standardization (PDS), and double window piecewise direct standardization (DWPDS)).

Molecular characterization of PoGT8D and PoGT43B, two secondary wall-associated glycosyltransferases in poplar.

Dicot wood is mainly composed of cellulose, lignin and glucuronoxylan (GX). Although the biosynthetic genes for cellulose and lignin have been studied intensively, little is known about the genes involved in the biosynthesis of GX during wood formation. Here, we report the molecular characterization of two genes, PoGT8D and PoGT43B, which encode putative glycosyltransferases, in the hybrid poplar Populus alba x tremula.

Development and use of an attenuated total reflectance/fourier transform infrared (ATR/FT-IR) spectral database to identify foreign matter in cotton.

The presence of foreign matter in cotton seriously affects the cotton grade and thus the price per bale paid by the spinner to the grower, the efficiency of the spinning and ginning operations, and the quality of the final woven product. Rapid identification of the nature of the extraneous matter in cotton at each stage of cleaning and processing is necessary to permit actions to eliminate or reduce its presence and improve efficiency and quality. Although several instruments are being successfully employed for the measurement of contamination in cotton fibers based on particle size/weight, no commercial instrument is capable of accurate qualitative identification of contaminants.

Corn stover fractions and bioenergy: chemical composition, structure, and response to enzyme pretreatment.

Information is presented on structure, composition, and response to enzymes of corn stover related to barriers for bioconversion to ethanol. Aromatic compounds occurred in most tissue cell walls. Ferulic acid esterase treatment before cellulase treatment significantly improved dry weight loss and release of phenolic acids and sugars in most fractions over cellulase alone.

Partial least squares regression calibration for determining wax content in processed flax fiber by near-infrared spectroscopy.

The quality of flax fiber in the textile industry is closely related to the wax content remaining on the fiber after the cleaning process. Extraction by organic solvents, which is currently used for determining wax content, is very time consuming and produces chemical waste. In this study, near-infrared (NIR) spectroscopy was used as a rapid analytical technique to develop models for wax content associated with flax fiber.

Chemical and spectroscopic analysis of lignin in isolated flax fibers.

The chemistry of pure flax fibers, free of contaminating nonfiber components, has not been determined. Fibers from the center sections of the stem of seed and fiber flax (Linum usitatissium L.), which had been retted after soaking in water and removal of the epidermis by hand, underwent chemical and spectroscopic analysis.

Caffeoyl coenzyme A O-methyltransferase and lignin biosynthesis.

Lignin, a complex phenylpropanoid compound, is polymerized from the monolignols p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. These three monolignols differ only by the 3- and 5-methoxyl groups. Therefore, enzymatic reactions controlling the methylations of the 3- and 5-hydroxyls of monolignol precursors are critical to determine the lignin composition.

Essential role of caffeoyl coenzyme A O-methyltransferase in lignin biosynthesis in woody poplar plants.

Caffeoyl coenzyme A O-methyltransferase (CCoAOMT) has recently been shown to participate in lignin biosynthesis in herbacious tobacco plants. Here, we demonstrate that CCoAOMT is essential in lignin biosynthesis in woody poplar (Populus tremula x Populus alba) plants. In poplar stems, CCoAOMT was found to be expressed in all lignifying cells including vessel elements and fibers as well as in xylem ray parenchyma cells.

FT-IR microspectroscopic imaging of flax (Linum usitatissimum L.) stems.

Fourier transform infrared (FT-IR) microspectroscopy was used to image and subsequently produce maps of the distribution chemical components in flax stem tissue. Cross-sections of two flax cultivars, Ariane and Natasja, were examined. The infrared maps produced were keyed to the visible images of the samples, thus permitting superimposition of chemical composition onto anatomical structure.

Ultrastructural and chemical examination of paper and pedicel from laboratory and field nests of the social waspPolistes metricus say.

The ultrastructure and chemical composition of paper and pedicel from nests ofPolistes metricus that were constructed in the laboratory from known building material were compared to paper and pedicel from nests constructed in the field. Scanning electron micrographs showed the addition of a gluelike secretion from the wasp to the construction material. Solid-state [(13)C]NMR, elemental analyses, and amino acid analyses indicate that this secretion is a silklike protein with serine, glycine, alanine, and proline comprising 65-73% of the identified residues.

Characterization of pedicel, paper, and larval silk from nest ofPolistes annularis (L.).

The pedicel, nest paper, and larval silk ofPolistes annularis nests were analyzed by high-resolution solid-state [(13)C]NMR. The pedicel was found to have a high nitrogen content (11%), and the NMR spectra indicated that it is a mixture of carbohydrate and protein. The pedicel protein has an amino acid composition that is very rich in glycine, alanine, serine, and proline (67% of identified residues), similar to that of some insect silks.

Assay for trans-p-coumaroyl esterase using a specific substrate from plant cell walls.

Cell walls of Coastal Bermuda grass (Cynodon dactylon) were treated with polysaccharide hydrolases to release O-[5-O-(trans-p-coumaroyl)-alpha-L-arabinofuranosyl]-(1----3)-O-be ta-D- xylopyranosyl-(1----4)-D-xylopyranose (PAXX) which was isolated by liquid chromatography. The isolated PAXX was greater than 95% pure as determined by 1H NMR and was used as substrate for a sensitive assay of trans-p-coumaroyl esterase. PAXX was hydrolyzed by culture filtrates from the anaerobic fungus Neocallimastix MC-2.

Determination of epimeric 1-(3-indolyl) propane -1,2,3-triol isolated from Balansia epichloe.

Investigations into diseases in cattle grazing on grass pastures infected with clavicipitaceous fungi have resulted in the isolation and characterization of erythro and threo 1-(3-indolyl) propane-1,2,3-triol from cultures of Balansia epichloë (Weese). Gas chromatography-mass spectroscopy analyses of synthetic and natural epimers as their trimethylsilyl derivatives is described. Toxicity studies with fertile chicken eggs demonstrated that the threo epimer was the more active compound.