Delayed cotyledon senescence following treatment with a cytokinin; an effect at the level of membranes

1980 ◽  
Vol 58 (16) ◽  
pp. 1797-1803 ◽  
Author(s):  
M. L. Gilbert ◽  
J. E. Thompson ◽  
E. B. Dumbroff

Application of 10−4 M benzyladenine to Phaseolus vulgaris germinated under etiolating conditions markedly delayed the onset of cotyledon senescence. Weight loss was curtailed, hydrolysis of starch and protein reserves was delayed, and the rate at which hydrolysis products were translocated out of the cotyledons was reduced in treated plants. Microsomal membranes of cotyledons from control seedlings acquired increasing proportions of gel phase lipid as senescence of the tissue intensified. The resulting mixture of liquid-crystalline and gel phase lipid within the membrane matrix renders the membranes leaky and may partially contribute to metabolite translocation out of the cotyledon storage cells during seedling development. This prospect is supported by the observation that in benzyladenine-treated plants the onset of gel phase lipid, and hence of membrane leakiness, was delayed in a manner that corresponded temporally with the decreased rate of metabolite translocation out of the cotyledons.

2018 ◽  
Vol 68 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Barbara Król-Kogus ◽  
Khenifi Mohammed Lamine ◽  
Piotr Migas ◽  
Messaoud Boudjeniba ◽  
Mirosława Krauze-Baranowska

Abstract A new HPTLC-densitometric method for diosgenin determination in fenugreek seeds was established after optimization of the conditions for efficient saponin extraction and acid hydrolysis. Several procedures were tested, the best of which was a three-step Soxhlet extraction, followed by hydrolysis of the obtained methanolic extract with 2 mol L-1 H2SO4. Best diosgenin separation from other hydrolysis products was obtained on HPTLC Si60F254 plates u sing a mixture of n-heptane/ethyl acetate (7:3, V/V) and modified anisaldehyde as a spraying reagent. The method was preliminarily validated and the determined amounts of diosgenin in fenugreek seeds of Polish and African origin were found to be similar and ranged from 0.12-0.18 %.


1988 ◽  
Vol 255 (3) ◽  
pp. F520-F528 ◽  
Author(s):  
C. H. Park

The time course and vectorial nature of renal metabolism of albumin (Alb) were studied. The tubular absorption, accumulation, and hydrolysis of Alb and the release of the hydrolysis products were determined in the isolated rabbit proximal convoluted tubule (PCT) perfused with tritiated Alb ([3H3C]Alb) at 36.4 micrograms/ml. The Alb absorption across the apical membrane was constant (99.9 +/- 4.9 x 10(-3) ng.min-1.mm-1). In contrast, the accumulation and hydrolysis of Alb in the cells increased nonlinearly with time. The bulk of the tritium that accumulated in the cells was associated with intact [3H3C]Alb. Only the final hydrolysis products were released from the cells and these first appeared in the peritubular bath 6–7 min after the start of perfusion of the tubule with [3H3C]Alb. The hydrolysis product was not detectable in the tubule lumen. The proteolytic activity correlated linearly with the protein load to the cells, characteristic of first-order kinetics and a high-capacity system. The results suggest that the renal tubular handling of proteins proceeds from the apical to the basolateral aspect of the cell. The transcellular processing of Alb is rapid and can occur in 6–7 min. The accumulation of intact protein in the cell and the first-order kinetics of hydrolysis of the absorbed protein suggest that the rate-limiting step in proximal tubular handling of proteins may include the initial hydrolysis of protein or reside in steps that precede the hydrolysis.


LWT ◽  
2020 ◽  
Vol 125 ◽  
pp. 109191
Author(s):  
Francine Gomes Basso Los ◽  
Ivo Mottin Demiate ◽  
Rosa Cristina Prestes Dornelles ◽  
Buddhi Lamsal

RSC Advances ◽  
2015 ◽  
Vol 5 (89) ◽  
pp. 73112-73118 ◽  
Author(s):  
N. A. Rodríguez ◽  
R. Parra ◽  
M. A. Grela

Hydrolysis of MOF-5 gives place to a mixture of two compounds: MOF-5W and zinc terephthalate dihydrate. The analysis of optical and photochemical properties allows to infer the preeminence of a ligand to ligand charge-transfer.


Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2317
Author(s):  
Lang Zhou ◽  
Bryan Chin ◽  
Alex L. Simonian

Tricresyl phosphate (TCP) is an organophosphorous neurotoxin that has been detected in water, soil and air. Exposure to TCP in cockpit and cabin air poses a severe threat to flight safety and the health of the aircraft cabin occupants. Conventional methods for the detection of TCP in various samples are gas or liquid chromatography coupled to mass spectrometry, which are complex and expensive. To develop a simple low-cost methodology for the real-time monitoring of TCP in the environment, an effective catalyst is demanded for the hydrolysis of TCP under neutral condition. In this study, Ruthenium (III) hydroxide and Iron (III) hydroxide are found to facilitate the production of the alcoholysis and hydrolysis products of TCP, suggesting their role as a catalyst. With this finding, these metal hydroxides provide new potential to realize not only simple colorimetric or electrochemical detection of TCP, but also a simple detoxication strategy for TCP in environment. In addition, the catalytic capability of Ru (III) or Fe (III) hydroxide for TCP gives a hint that they can potentially serve as catalysts for the hydrolysis of alcolyolysis of many other organophosphate compounds.


2016 ◽  
Vol 71 (3) ◽  
pp. 249-265 ◽  
Author(s):  
Christina Taouss ◽  
Peter G. Jones

AbstractDiphosphanegold(I) complexes of the form dppmEAuX [dppm = bis(diphenylphosphano)methane, E = S, Se; X = Br, I], dppeEAuX [dppe = 1,2-bis(diphenylphosphano)ethane; E = O, S; X = Br, I] and dppbzEAuX [dppbz = 1,2-bis(diphenylphosphano)benzene; E = S, Se, X = Br, I] were treated with elemental X2. With dppm, the three products [dppmEAuX2]+X3– (E = S, X = Br (1), I (2); E = Se, X = I (3) were obtained in quantitative yield. These are gold(III) complexes involving a five-membered ring . With dppe, the only related product was [dppeEAuBr2]+Br3– (4), in which the central ring is six-membered with two carbon atoms. These dppe systems are very sensitive to oxidation/hydrolysis of the ligand, and several such unintended products were isolated and identified. The reaction of dppbzSAuBr with bromine leads to [dppbzS]2+[AuBr4]–Br– (5), the dication of which is formally 1,1,3,3-tetraphenylbenzo[d]-2-thia-1, 3-diphosphol-1,3-diium and contains a central five-membered ring . The dications are associated with the bromide anions via S…Br contacts of ca. 3.1 Å to form inversion-symmetric S2Br2 rings. The halogenation of the dppbzSe derivatives leads to loss of selenium and formation of dppbzAuBr3 (6), with [4+1] coordination at gold, or the known compound [dppbzAuI2]+I3– (7). All products 1–6 were subjected to X-ray diffraction analyses, as were four hydrolysis products 4a–d and two further by-products [5(thtBr+)·2Br3–·3(AuBr4–)] (1a) and (tht)AuBr3 (1b). Compound 1a displays unusually short Br…Br contacts of 3.2398(8) Å between neighbouring tetrabromidoaurate(III) ions.


1977 ◽  
Vol 165 (3) ◽  
pp. 575-580 ◽  
Author(s):  
B Bartholomew ◽  
K S Dodgson ◽  
G W J Matcham ◽  
D J Shaw ◽  
G F White

The hydrolysis was studied of potassium (+)-octan-2-yl sulphate by two analogous, optically stereospecific, secondary alkylsulphohydrolases purified from two detergent-degrading micro-organisms, Comamonas terrigena and Pseudomonas C12B. Polarimetry studies have shown that (+)-octan-2-yl sulphate prepared from (+)-octan-2-ol is hydrolysed by both enzymes to yield (-)-octan-2-ol. This inversion of configuration implies that the enzymes are catalysing the scission of the C-O bond of the C-O-S linkage, a type of bond scission apparently not hitherto encountered among hydrolytic enzymes acting on ester bonds. Enzymic hydrolysis of potassium (+)-octan-2-yl sulphate in the presence of H218O and analysis of hydrolysis products for the presence of 18O has confirmed that C-O bond scission (and not O-S bond scission) occurs with both enzymes.


Some time ago, two of the authors of the present communication, in seeking a method for the separation of the amino-acids from the carbohydrates, found that under certain conditions the former could be readily separated in the form of the barium salts of their carbamates, a class of compounds originally described by Siegfried. As these carbamates, on heating with water, are readily decomposed into barium carbonate and the free amino-acid, it was suggested that a convenient method might be evolved, using the formation of these compounds as a basis, for the separation of the hydrolysis products of the proteins.* This suggestion was followed up, and a method was subsequently elaborated and applied to the separation of the hydrolysis products of gelatin by one of the authors in conjunction with Miss H. L. Kingston. Since the publication of the two papers just quoted, the researches on the use of the “carbamate method,” as it may be conveniently called, have been continued, and promise results, which may ultimately lead to a satisfactory separation of most of the hydrolysis products of the proteins when only relatively small amounts of material are available for investigation. During the course of this work the base, which is the chief subject discussed in this paper, was discovered.


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