Modern methods of plant analysis
01 Jan 1964-
About: The article was published on 1964-01-01 and is currently open access. It has received 1991 citations till now.
Citations
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TL;DR: Cytokinin activity in extracts of nodules, roots, stems and leaves of Viciafaba L. was estimated using the soybean callus bioassay to estimate high levels of cytokinins while the amounts detected in roots and stems were much lower.
Abstract: SUMMARY Cytokinin activity in extracts of nodules, roots, stems and leaves of Viciafaba L. was estimated using the soybean callus bioassay. High levels of cytokinins were present in nodules and leaves while the amounts detected in roots and stems were much lower. Cytokinin levels in the root nodules were as much as twelve to thirteen times those detected in the roots. At least three kinds of cytokinins were present in the plant, two of which had similar chromatographic properties to the cytokinin zeatin and its riboside. The third cytokinin had properties which distinguished it from any of the known cytokinins. This peak was predominant in the leaves while the zeatin riboside-like peak was the main cytokinin detected in the root nodules and roots.
53 citations
TL;DR: Two substances attractive to honeybees have been isolated from mixed pollens and a free fatty acid which chromatographed was identified as a C18 straight-chain dienoic or trienoic acid.
Abstract: Two substances attractive to honeybees have been isolated from mixed pollens. One is a pigment which was identified as a lutein ester, the other is a free fatty acid which chromatographed was identified as a C18 straight-chain dienoic or trienoic acid.
53 citations
TL;DR: In this paper, five routes to stable chlorins bearing 0 or 1 meso substituents have been investigated, among which reaction of a 9bromo-1-formyldipyrromethane and 2,3,4,5-tetrahydro-1, 3,3-trimethyldiprin proved most effective.
53 citations
TL;DR: In this paper, modem sensory analysis of wine appellations was used for industry judge panels to determine judge quality biases using a multi-wine preference-testing method (n = 48) in which judges freely recorded their aroma terms.
Abstract: Since producer based sensory analysis of wine appellations remains in widespread use worldwide by wineries, modem sensory methods were developed for industry judge panels. U. S. appellations were studied using modem sensory analysis processes which accommodated the industry professionals' biases for perceived quality and provincial sensory language. A panel was assembled comprised of wine industry quality experts (n = 26). First, judge quality biases were determined using a multi-wine preference-testing method (n = 48) in which judges freely record their aroma terms. Subsequently QDA@ type strategies were used to create the sensory language from analysis of 1100 wine x judge interactions in which free use of terms was used to describe the wines. Next, an experiment analyzed the wines using a new descriptive analysis scorecard which contained the ten most frequently used terms; and scores were computed from the number of times terms were selected by the judges Pequency of use). Groups of sixteen wines, for which the judges had no large negative bias, from the Cameros American Viticultural Areas (AVA), were compared to those from California wine growing regions (Central Coast, Napa and Sonoma). Replicate trials showed Cameros AVA and Central Coast wines clustered in the principal components
53 citations
TL;DR: Walls of the resting spores of Plasmodiophora brassicae were isolated mechanically and analysed quantitatively for their major components and abnormally high levels of protein and lipid are discussed.
Abstract: Walls of the resting spores of Plasmodiophora brassicae were isolated mechanically and analysed quantitatively for their major components. At least 88 % of the spore wall dry weight was accounted for and shown to comprise 25.1% chitin, ≥ 2.5% other carbohydrates, 33.6% protein and ≥ 17.5% lipid while residual ash was equivalent to 10.5% of the total weight; chitosan and cellulose were absent from the walls. The significance of the abnormally high levels of protein and lipid is discussed.
53 citations
References
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01 Jan 1963
TL;DR: In this article, a physiologischer Vorgang auf eine enzymatische Wirkung zuruckgefuhrt werden (vgl. S. 301), besteht die folgende Aufgabe darin, Naheres uber die Eigenschaften des beteiligten Enzyms zu ermitteln.
Abstract: Kann ein physiologischer Vorgang auf eine enzymatische Wirkung zuruckgefuhrt werden (vgl. S. 301), so besteht die folgende Aufgabe darin, Naheres uber die Eigenschaften des beteiligten Enzyms zu ermitteln. Hierzu gehoren die Bestimmung der Reaktions- und Substratspezifitat sowie die Ermittlung der Bedingungen, unter denen eine optimale Wirkung des Enzyms gegeben ist. Wesentlich zur Charakterisierung ist ferner die Untersuchung der Stabilitat des Enzyms und dabei insbesondere die Feststellung, ob es sich um ein Ferment handelt, das zur vollen Aktivitat dialysable Cofaktoren benotigt. Falls diese Frage bejaht wird, ist auch die Bestimmung der unerlaslichen Cofaktoren anzuschliesen. Uberdies bietet auch der Nachweis der Lokalisation des Enzyms in der Zelle (oder im Zellverband) eine entscheidende Moglichkeit zur Charakterisierung des Fermentes. Hinzu kommt schlieslich noch die Untersuchung der Wirkung einzelner Inhibitoren1 auf das Enzym, die zu weitgehender Klarung des Reaktionsmechanismus beitragen kann und eine Abgrenzung der Eigenschaften des untersuchten Fermentes gegenuber ahnlichen Enzymen erlaubt.
2 citations
01 Jan 1962
TL;DR: Optical rotation has been found to be one of the most convenient methods of following the denaturation of proteins and rotatory dispersion is capable of providing information on the folding of the polypeptide chain in proteins and the changes accompanying denaturation.
Abstract: Optical rotation has been found to be one of the most convenient methods of following the denaturation of proteins. Generally speaking denaturation can be defined as a process or sequence of processes in which the spatial arrangement of the polypeptide chains within the molecule is changed from that typical of the native protein to a more disordered arrangement (Kauzmann 1959). The terms “configuration”, “conformation” and “state of folding” are widely used for spatial arrangement. It is probably best to follow the suggestion of Blout (1960) and restrict the use of “configuration” to its original sense, i.e. the spatial arrangement around an asymmetric carbon atom, and to use “conformation” for the shape of the molecule in its entirety. The properties discussed in the previous Chapter i.e., viscosity, diffusion, sedimentation, and light scattering — can all furnish information on the overall shape of proteins or other macromolecules and changes in this shape with environment. Thus Doty, Bradbury and Holtzer (1956) were able to show using these methods, together with streaming birefringence, that poly-γ-benzyl-L-glutamate could exist in two conformations, the α-helix and the solvated randomly coiled form, depending on the solvent. The change from α-helix to random coil was accompanied by marked changes in the optical rotatory properties of the polypeptides. It is to be expected that an α-helical structure should contribute to the rotatory power of a polypeptide since helices are asymmetric and not superimposable on their mirror images. The work on polypeptides has shown that rotatory dispersion is capable of providing information on the folding of the polypeptide chain in proteins and the changes accompanying denaturation.
1 citations