Helianthus tuberosus and polyamine research: Past and recent applications of a classical growth model

Abstract

The earliest studies concerning polyamines (PAs) in plants were performed by using in vitro cultured explants of Helianthus tuberosus dormant tuber. This parenchyma tissue was particularly useful due to its susceptibility to several growth substances, including PAs. During tuber dormancy, PA levels are too low to sustain cell division; thus Helianthus represents a natural PA-deficient model. When cultivated in vitro in the presence of auxins, Helianthus tuber dormant parenchyma cells at the G(0) stage start to divide synchronously acquiring meristematic characteristics. The requirement for auxins to induce cell division can be substituted by aliphatic PAs such as putrescine, spermidine or spermine. Cylinders or slices of explanted homogeneous tuber parenchyma were cultured in liquid medium for short-term studies on the cell cycle, or on solid agar medium for long-term experiments. Morphological and physiological modifications of synchronously dividing cells were studied during the different phases of the cell cycle in relation to PAs biosynthesis and oxidation. Long-term experiments led to the identification of the PAs as plant growth regulators, as the sole nitrogen source, as tuber storage substances and as essential factors for morphogenetic processes and cell homeostasis. More recently this system was used to study the effects on plant cell proliferation of platinum- or palladium-derived drugs (cisplatin and platinum or palladium bi-substituted spermine) that are used in human cancer cell lines as antiproliferative and cytotoxic agents. Cisplatin was the most active both in cell proliferation inhibition and on PA metabolism. Similar experiments were performed using three agmatine analogous. Different effects of these compounds were observed on cell proliferation, free PA levels and enzyme activities, leading to a hypothesis of a correlation between their chemical structure and the agmatine metabolism in plants.

Chemotherapeutic response to cisplatin-like drugs in human breast cancer cells probed by vibrational microspectroscopy

“…The data obtained within this work, coupled to conformational analysis of the metal complexes and cytological assays (for evaluation of growth-inhibition, cytotoxic and anti-metastatic activities) previously carried out at QFM-UC, [14][15][16]22,[25][26][27][40][41][42][43][44][45] will pave the way for future studies on other platinum and palladium-based polyamine agents prepared by the authors. This approach should provide valuable clues for the rational design of novel cisplatin-like drugs, displaying a higher efficiency, lower toxicity, decreased acquired resistance and possible oral administration.…”

A new approach for achievement of inulin accumulation in suspension cultures of Jerusalem artichoke (Helianthus tuberosus) using biotic elicitors

“…It is also called the sunchoke, or earth apple [39]. In addition it is native to temperate regions of North America and has been grown in Europe since the 17th century [34].…”

Spermine delays leaf senescence in Lactuca sativa and prevents the decay of chloroplast photosystems

“…Contrary to animal cells, plant cells can buffer against an excess of PAs, by forming conjugates, such as cinnamoyl acids (mainly perchloric acid (PCA)-soluble), or by storing them in the vacuole and cell wall [1]. The role of a noncovalent interaction of PAs with nucleic acids or other molecules has been recognised for a long time [42]. PAs can also be conjugated to proteins through the action of transglutaminases (TGases), a family of calcium-dependent enzymes.…”

“…TGases catalyse interactions between an acyl-acceptor glutamyl residue and amine donors, such as lysyl residues or PAs, forming cross-links within the same or between different proteins. PAs act as physiological substrates of TGases: the terminal amino-group binds one or two glutamyl residues giving rise either to mono-(g-glutamyl)-PAs or bis-(g-glutamyl)-PAs [18,42]. In the first case, PAs purportedly add positive charges to the protein causing them to bind with noncovalent linkages to other molecules.…”