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The ability for plant regeneration from dedifferentiated cells opens up the possibility for molecular bioengineering to produce crops with desirable traits. Developmental and environmental signals that control cell totipotency are regulated by gene expression via dynamic chromatin remodeling. Using a mass spectrometry-based approach, we investigated epigenetic changes to the histone proteins during callus formation from roots and shoots of Arabidopsis thaliana seedlings. Increased levels of the histone H3.3 variant were found to be the major and most prominent feature of 20-day calli, associated with chromatin relaxation. The methylation status in root- and shoot-derived calli reached the same level during long-term propagation, whereas differences in acetylation levels provided a long-lasting imprint of root and shoot origin. On the other hand, epigenetic signs of origin completely disappeared during 20 days of calli propagation in the presence of histone deacetylase inhibitors (HDACi), sodium butyrate, and trichostatin A. Each HDACi affected the state of post-translational histone modifications in a specific manner; NaB-treated calli were epigenetically more similar to root-derived calli, and TSA-treated calli resembled shoot-derived calli.

Hydroponic experiments were performed to examine the effect of prolonged sulfate limitation combined with cadmium (Cd) exposure in Arabidopsis thaliana and a potential Cd hyperaccumulator, Nicotiana tabacum. Low sulfate treatments (20 and 40 µM MgSO 4 ) and Cd stress (4 µM CdCl 2 ) showed adverse effects on morphology, photosynthetic and biochemical parameters and the nutritional status of both species. For example, Cd stress decreased NO 3 - root content under 20 µM MgSO 4 to approximately 50% compared with respective controls. Interestingly, changes in many measured parameters, such as chlorophyll and carotenoid contents, the concentrations of anions, nutrients and Cd, induced by low sulfate supply, Cd exposure or a combination of both factors, were species-specific. Our data showed opposing effects of Cd exposure on Ca, Fe, Mn, Cu and Zn levels in roots of the studied plants. In A. thaliana, levels of glutathione, phytochelatins and glucosinolates demonstrated their distinct involvement in response to sub-optimal growth conditions and Cd stress. In shoot, the levels of phytochelatins and glucosinolates in the organic sulfur fraction were not dependent on sulfate supply under Cd stress. Altogether, our data showed both common and species-specific features of the complex plant response to prolonged sulfate deprivation and/or Cd exposure., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Organic ammonium salts of N-(2-benzoyloxyethyl)-alkyldimethylammonium bromide (BCHn-1) type are formed by the homological series Ar-COO(CH2)2-N+(CH3)2CnH2a + 1.Br-, whose structure contains a biodegradably labile ester bond, on the basis of which they rank among disinfectants and antiseptics of soft character. They are preferentially biotransformed hydrolytically to produce benzoic acid and substituted choline. The rapidity of enzymatic hydrolysis depends on the chemical structure (the length of the aliphatic chain on the ammonium nitrogen), it increases up to the number of 10 nitrogens of the aliphatic chain, and it rapidly decreases with further prolongation. The paper aimed to demonstrate the catalytic activity of butyrylcholinesterase on the enzymatic hydrolysis of selected organic ammonium salts in the medium of the microsomal fraction of the rat liver on the basis of inhibitory kinetic studies with physostigmine, a cholinesterase inhibitor. The product of enzymatic hydrolysis of BCHn-1, benzoic acid, was determined after extraction with chloroform from the acid medium by means of HPLC analysis with the use of the internal standard p-iodobenzoic acid at the wavelength of 228 nm. Kinetic parameters K(M) and VMAX were evaluated following Lineweaver-Burke using the method of linear regression analysis. The specific activity of butyrylcholinesterase (E.C.3.1.1.8) in the enzymatic hydrolytic process of BCHn-1 was significantly influenced by the presence of physostigmine, which was manifested by increased K(M), KI, and IC50 values in the investigated enzymatic process of selected substrates of the homological series BCHn-1, and by decreased VMAX and rate constants.

The study evaluated the rate and kinetics of enzymatic hydrolysis of N-(2-benzoyloxyethyl)-alkyl-dimethylammonium bromides, potential easily biodegradable disinfectants of soft character. The products of enzymatic hydrolysis of the substrates under study, catalysed by microsomal esterase, included substituted substrates choline and benzoic acid which, as a hydrolytic product, was essayed by HPLC. The effect of the length of the alkyl chain of the individual homologues on the rate of enzymatic hydrolysis and their affinity to microsomal esterase of the rat liver and lung in vitro was examined. The structural modification (varying length of the aliphatic chain on the ammonium nitrogen of these compounds) was found to significantly influence the kinetics of enzymatic hydrolysis of the esteric bond. From the viewpoint of the rate of enzymatic hydrolysis no significant inter-organ variability was observed: in the liver as well as the lung the dependence of the rate of enzymatic hydrolysis on the length of the aliphatic chain possesses the shape of a falling hyperbole with the maxima for BCH2 > BCH4 > BCH8 = BCH10. The specific activity of both esterases ranges within 0.2-3.5 nmol.min-1.mg-1. From the viewpoint of affinity, a marked inter-organ difference was manifested by 10 times higher affinity of the substrates to the lung microsomal esterase in comparison with the liver one. The effect of the length of the alkyl of the individual homologues on the affinity is of a non-linear character also in this case. In both organs, a certain correlation was found between the rate of enzymatic hydrolysis and affinity to microsomal esterases.

Dokloxytepin in the medium of the induced monooxygenase system of the microsomal fraction of the liver of the rat, rabbit and mice is metabolized into three metabolites: two identical, i.e., N-oxide and 5-sulfoxide, and a third different one. In the rat and rabbit it is the hitherto unknown metabolite M1, and in the mouse S,N-dioxide of dokloxytepin. The metabolites were identified by thin-layer chromatography by comparing with synthetic standards.

Oxyprothepine in the medium of the microsomal fraction of the rat liver is biotransformed to the corresponding metabolites originating by oxidation of both sulfur atoms. The formation of S-oxygenation products is bound to the presence of NADPH, with a marked synergism with NADH. Induction with phenobarbital increases the formation of the individual metabolites.

A new procedure for obtaining rat lung microsomes essentially free of interfering hemoproteins has been developed. The method includes Sepharose 2B column chromatography of the 12,000 X g supernatant of lung homogenates, followed by ultracentrifugation of the material eluted in the void volume. Microsomes isolated in this manner contain specific levels of cytochromes b5 and P-450 and of NADPH-cytochrome c reductase that are among the highest ever reported for a rat lung microsomal fraction. After treatment of rats with 3-methylcholanthrene, the specific content of cytochrome P-450 in lung microsomes is doubled and that of cytochrome b5 increases 1.5 times. Several spectral differences between hepatic and lung microsomal cytochrome P-450 are apparent. In lung microsomes, the maximum of the reduced CO-bound cytochrome complex in a difference spectrum is at 453 nm for the noninduced hemoprotein and shifts to 451 nm after 3-methylcholanthrene induction. In contrast, no significant change in the ethylisocyanide difference spectra of reduced microsomes is obtained after induction; moreover, the spectra obtained with induced and noninduced cytochrome P-450 are similar to the one shown by hepatic microsomes from polycyclic hydrocarbon-treated rats. Furthermore, spectrophotometric studies on n-octylamine binding to control and induced lung cytochrome P-450 yielded results different from those previously obtained with rabbit liver microsomes. It is concluded that the cytochrome P-450 present in rat lung microsomes before and after 3-methylcholanthrene treatment of the animals is distinctly different from the liver hemoprotein.