Anti-pathogenic properties of plant peptide hormone phytosulfokines [PSK's] and its selected analogues

Phytosulfokine-α (PSK-α) (H-Tyr(SO3H)-Ile-Tyr(SO3H)-Thr-Gln- OH) (I), a sulfated growth factor universally found in both monocotyledons and dicotyledons, strongly promotes proliferation of plant cells in culture. The C-terminal truncated analog named PSK-β (Tyr(SO3H)-Ile-Tyr(SO3H)-Thr) (II) showed a 10-fold lower activity than that of the parent pentapeptide. Because PSK-α promotes proliferation and differentiation during the plant growth we undertook the studies on the influence of PSK-α on plant defense mechanisms in that period. In present studies on PSK-α (I), PSK-β (II), and its analogues, we performed a search of another biological properties. The aim of our investigation was evaluation of PSK-α, PSK-β and their selected analogues in relation to growth and development of plant pathogens, such as Phoma narcissi and Botrytis tulipae. In these studies we elaborated the synthesis of PSK-α or PSK-β and their 22 analogues modified by natural and non-natural amino acid residues. Peptides were synthesized by the solid phase method according to the Fmoc procedure on a Wang-resin. Free peptides were released from the resin by 95% TFA in the presence of EDT. Biological effect of these peptides was evaluated by test on the growth and development of pathogens of P. narcissi and B. tulipae.</p

The search for new biological activities for selected insect peptides

New biological properties of selected insect peptides are presented. The subjects of the investigation included insect oostatic peptides, like Neb-colloostatin (I) and Neb-TMOF(II), and/or insect peptides with antiviral or antitumor activity, such as alloferon (III) and its analogues modified at position 1 of the peptide chain. In the study was also included the oligopeptide Any-GS (VII) and its truncated analogues. The peptides were tested for antimicrobial activity on a series of bacterial species, antiviral activity against Human Herpes Virus type 1 (HHV-1) in vitro using a Vero cell line, and the growth and development of plant pathogens Phoma narcissi and Botrytis tulipae. The results of the biological investigations indicate that among the peptides investigated, compounds VII and IX inhibit the growth of plant pathogens P. narcissi and B. tulipae, whereas compounds I and II stimulate the mycelium growth of the aforementioned pathogens. Other peptides show slow antimicrobial activity but do not inhibit the replication of HHV-1 in Vero cells