Variation of the Nuclear, Subnuclear and Chromosomal Flavanol Deposition in Hemlock and Rye

Walter Feucht,Heike Dithmar,Jürgen Polster

doi:10.3390/i8070635

Walter Feucht, Heike Dithmar + Show 1 more

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https://doi.org/10.3390/i8070635

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Abstract

Nuclei of hemlock (Tsuga canadensis and Tsuga canadensis var. nana) wereinvestigated for the presence of flavanols. Histochemical staining with p-dimethylaminocinnamaldehyde proved to be a highly valuable method yielding a brightblue flavanol coloration for nuclei. There was a significant variation in flavanol deposition(1) among nuclei, (2) at the subnuclear level and also (3) along the chromosomes duringmitosis. The presence of flavanols in nucleoli could not be established probably becausethey were too small, measuring less than 1 μm in diameter. In contrast to Tsuga, the cellsand nuclei of rootlets from rye (Secale cereale) were totally devoid of natural flavanols.However, externally added flavanols, catechin and epicatechin, were bound to the ryenuclei, while the rather large nucleoli failed to associate with the flavanols. The strong sinkactivity of nucleoplasm and chromosomes for flavanols in Tsuga and Secale indicates aprocess which is apparently widespread even in distantly related plant species. Variationsin chromatin-associated flavanols could to some extent be induced byacetylation/deacetylation of histones, as confirmed in the present study by means of UV-VIS spectroscopic titrations of histone sulphate and chemically acetylated histone sulphate.

Highlights

There is conclusive evidence based on different methods that flavanols as a subclass of the flavonoids are naturally located in nuclei of coniferous trees [1,2,3,4], whereby histone proteins forming nucleosome structures with DNA were found to associate with flavanols [4]
Flavanols reacting with the DMACA reagent were generally found to be bound in different intensities in the nuclei of hemlock trees
Most important, no natural flavanols were found in the nuclei of rye rootlets, but when added externally they bind strongly to the intact chromatin system

Summary

Introduction

There is conclusive evidence based on different methods that flavanols as a subclass of the flavonoids are naturally located in nuclei of coniferous trees [1,2,3,4], whereby histone proteins forming nucleosome structures with DNA were found to associate with flavanols [4]. In this context, it is of interest that chalcone synthases, the starter enzymes for flavonoids, were found in nuclei of Arabidopsis [5]. Such freely moving histones might be scavenged by flavanols

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