1,721,176 research outputs found
Comparing Two Systems for Digital Photogrammetry: a Metric Camera & a Photogrammetric Scanner versus a Semimetric Camera & a DTP Scanner
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A comprehensive molecular approach to the detection of drug-type versus fiber-type hemp varieties
No full textThe availability of molecular markers able to distinguish drug-type from fiber-type Cannabis sativa cultivars would allow fast and cheap analysis of any plant specimen, including seeds and leaves. Several approaches to this issue have been described, mainly using polymorphisms in the genes coding for tetrahydrocannabinol acid synthase or cannabidiolic acid synthase. Some studies reported sequencing of these genes from small groups of hemp varieties belonging to both chemotypes, showing the occurrence of specific DNA signatures. However, the effectiveness of the corresponding primers to discriminate among chemotypes has been validated on a limited number of cultivars, or not tested at all. Here we report a thorough in silico analysis of available gene sequences for both synthases, showing the existence of hypervariable regions at 3’ and 5’ ends. This notwithstanding, some possible signatures were identified, and 12 putatively specific primer pairs were designed and tested on 16 fiber-type and 11 drug-type varieties. In most cases inconsistent results were obtained, further strengthening the high genetic variability of these genes in hemp germplasm, yet some highly informative polymorphisms were identified. Potentiality and perspectives of this approach are discussed
A Specific and Sensitive Enzymatic Assay for the Quantitation of L-Proline
No full textBecause proline accumulates rapidly in response to several stress conditions such as drought and excess salt, increased intracellular levels of free proline are considered a hallmark of adaptive reactions in plants, particularly in response to water stress. Proline quantitation is easily achievable by reaction with ninhydrin, since under acidic conditions peculiar red or yellow reaction products form with this unique cyclic amino acid. However, little attention has been paid to date to cross-reaction of ninhydrin with other amino acids at high levels, or with structurally related compounds that may also be present at significant concentrations in plant tissues, possibly leading to proline overestimation. In vitro at high pH values, δ1-pyrroline-5-carboxylate reductase, the enzyme catalyzing the second and last step in proline synthesis from glutamate, was early found to catalyze the reverse oxidation of proline with the concomitant reduction of NAD(P)+ to NAD(P)H. Here we characterized this reverse reaction using recombinant enzymes from Arabidopsis thaliana and Oryza sativa, and demonstrated its utility for the specific quantification of L-proline. By optimizing the reaction conditions, fast, easy, and reproducible measurement of L-proline concentration was achieved, with similar sensitivity but higher specificity than the commonly used ninhydrin methods
Catasto Stradale, Mobile Mapping e Navigazione Geodetica nelle Reti di Stazioni Permanenti
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Building detection and roof extraction in laser scanning data
No full textA strategy for building detection and roofs extraction, relying on airborne laser scanning data only is presented, which ultimately aims at object reconstruction. Roofs are modeled as plane surfaces, connected along ridges and bordered by the eaves lines. Detection is performed by first removing the terrain pixels by smooth interpolation and then applying region growing to group elevated regions, later filtered out to select those likely to represent buildings. Roof extraction is obtained by classifying pixels in each region as roof slopes, ridges, building outlines. Roofs slopes are identified by finding plane surfaces which are segmented based on gradient orientation. The same procedure is used to extract roof outlines, further segmented in eaves lines. The topology of the roof slopes and walls is finally reconstructed, which allows to compute roof ridges and roof corners. Examples from a laser scanning survey with a ground sampling of 1 m are presented
Delta-1-pyrroline-5-carboxylate dehydrogenase from cultured cells of potato
No full textDelta(1)-Pyrroline-5-carboxylate (P5C) dehydrogenase (EC 1.5.1.12), the second enzyme in the proline catabolic pathway and a catalyst for the oxidation of P5C to glutamate, was purified from cultured potato (Solanum tuberosum L. var Desiree) cells. Homogeneous enzyme preparations were obtained by a three-step procedure that used anion-exchange, adsorption, and substrate elution chromatography. A 1600-fold purification was achieved, with a recovery of one-third of the initial activity. The purified enzyme was characterized with respect to structural, kinetic, and biochemical properties. It appeared to be an alpha-4 tetramer with subunits of an apparent molecular mass of about 60 kD and had a mildly acidic isoelectric point value. Potato P5C dehydrogenase had Michaelis constant values of 0.11 and 0.46 mm for NAD(+) and P5C, respectively. Although NAD(+) was the preferred electron acceptor, NADP(+) also yielded an unusually high rate, and thus was found to serve as a substrate. Maximal activity was observed at pH values in the 7.3 to 8.3 range, and was progressively inhibited by chloride ions, a finding that strengthens recent suggestions that hyperosmotic stress negatively modulates in vivo proline oxidation
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