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.
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TL;DR: Determination of magnesium by this method was particularly satisfactory, and results were more reliable than those obtained by direct titration of milk; results for potassium and sodium were comparable to those obtaining by flame photometry.
54 citations
TL;DR: In this article, the effect of NH 4 + and NO 3 on phosphorus uptake and plasma membrane H+ ATPase activity in rice was investigated, and it was shown that the stimulated uptake of phosphorus by NH 4+ versus NO 3 - nutrition may be related to the activity of plasma membrane ATPase.
Abstract: Aims
Nitrogen, especially NH 4 + , can stimulate the uptake of phosphorus in plants, but the underlying mechanisms have not been clearly elucidated. Because phosphate is taken up via an anion/H+ co-transport process, we propose that the stimulated uptake of phosphorus by NH 4 + versus NO 3 - nutrition may be related to the activity of plasma membrane H+ ATPase. In the present study, we investigated the effect of NH 4 + and NO 3 - on phosphorus uptake and plasma membrane H+ ATPase activity in rice.
54 citations
TL;DR: Bulgarian genotypes were spread over the two groups suggesting that they are not subject to genetic erosion and that the Phaseolus genetic diversity is conserved.
54 citations
TL;DR: The significant antifungal activity of these oils suggests that they could serve as a source of compounds with therapeutic potential against Candida-related infections.
Abstract: BACKGROUND/PURPOSE: Candida species, notably Candida albicans, is the major fungal pathogen in humans. It is a dimorphic fungus capable of causing superficial mucosal infections, as well as systemic infections, in immunocompromised individuals. The factors responsible for its pathogenesis are still not fully understood and increasing resistance to commonly used antifungal agents necessitates the search for new formulations. METHODS: The inhibitory effect of 30 different plant oils on Candida albicans isolated from clinical samples was evaluated. The antifungal agent fluconazole was used as a positive control. Plant oils were tested at concentrations from 0.03% to 3% (v/v) to determine the minimum inhibitory concentration and minimum fungicidal concentration (MFC) using agar dilution and macro broth dilution assays. RESULTS: Of the 30 plant oils tested, 18 were found to be effective and 12 were ineffective. Based on their MFCs, effective oils were placed into three categories: most effective, moderately effective and least effective. Eucalyptus and peppermint oils were most effective, with MFC values of 0.12% and 0.15% (v/v), respectively. CONCLUSION: The significant antifungal activity of these oils suggests that they could serve as a source of compounds with therapeutic potential against Candida-related infections.
54 citations
TL;DR: In this paper, the first investigation reported an improved essential oil content under UV-B supplementation in aromatic plants under field conditions, while no effect was found on the qualitative composition of the essential oils, whereas the quantitative composition was slightly modified in chemotype I.
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