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: It is shown that antioxidant compounds in red wine can associate with LDL particles following an incubation in whole plasma, can exert an antioxidant effect and, in so doing, can inhibit the uptake of the lipoprotein by macrophages.
248 citations
TL;DR: In this article, the authors describe the principles and particular characteristics of the plants' fluorescence signatures, of fluorescence imaging in general and of the Karlsruhe/Strasbourg high-resolution multi-colour imaging system FIS.
246 citations
TL;DR: The results are consistent with the view that, despite their diverse origin and function and their chemical differences, plant and bacterial ferredoxins have similar characteristics as electron carriers.
238 citations
TL;DR: The sulfuric acid method was successfully applied to determine the β‐glucan, mannan and chitin contents in cell walls of genetically well‐characterized yeast mutants defective in cell wall biosynthesis, and in Schizosaccharomyces pombe cell walls.
Abstract: A reliable acid hydrolysis method for quantitative determination of the proportion of beta-glucan, mannan and chitin in Saccharomyces cerevisiae cell wall is reported together with a simple extraction procedure to quantify within a standard error of less than 2% the proportion of the wall per gram of cell dry mass. This method is an optimized version of Saeman's procedure based on sulfuric acid hydrolysis of complex polysaccharides. It resulted in an almost complete release of glucose, mannose and glucosamine residues from cell wall polysaccharides. After complete removal of sulfate ions by precipitation with barium hydroxide, the liberated monosaccharides were separated and quantified by high performance anion-exchange chromatography with pulsed amperometric detection. The superiority of this method over the hydrolysis in either trifluoroacetic or hydrochloric acid resides in its higher efficiency regarding the release of glucose from beta 1,6-glucan and of glucosamine from chitin. The sulfuric acid method was successfully applied to determine the beta-glucan, mannan and chitin contents in cell walls of genetically well-characterized yeast mutants defective in cell wall biosynthesis, and in Schizosaccharomyces pombe cell walls. The simplicity and reliability of this procedure make it the method of choice for the characterization of cell walls from S. cerevisiae mutants generated in the EUROFAN programme, as well as for other pharmacological and biotechnological applications.
237 citations
TL;DR: Selenium will be an important antimutagen, at least in New Zealand, possibly through antioxidant effects associated with selenium's role in enzymes associated with endogenous repair of DNA damage, and the combination of each of these factors could provide a sustainable intervention that might usefully delay the development of cancer inNew Zealand and other populations.
236 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