Antibacterial activity of seed proteins of Robinia pseudoacacia

A low molecular weight cationic peptide was isolated from Robinia pseudoacacia seed and tested in vitro against seven bacteria (Corynebacterium michiganense, Staphylococcus aureus, Bacillus subtilis, Erwinia carotovora subsp. carotovora, Pseudomonas syringae pv syringae, Xanthomonas campestris pv campestris, and Escherichia coli). The peptide inhibited the growth of the tested strains. The effective concentrations required for 50% inhibition of bacterial growth ranged between 20 and 120 mug ml(-1) protein. S. aureus was found to be the most sensitive strain, however, E. coli was not affected much when compared with others. Reduction of antibacterial activity of the peptide with CaCl2 addition into the growth medium was also observed. (C) 2004 Elsevier B.V. All rights reserved

Investigations on biotechnologically developed poplar clones as raw material for pulp and paper industry

In this review an overview of our research on biotechnologically developed poplar clones for application in paper and pulp industry was presented. Nine native clones of Populus tremula as well as five hybrid clones of P. deltoides x P. deltoides were used for establishment of plant tissue culture system. For this purpose 'Woody Plant Medium' (WPM), supplemented with 1 mg/l zeatine (WPMZ) and WPM supplemented with 0.5 mg/l indole-3-butyric acid (IBA) (WPMB), were used for shoot and root regeneration, respectively. Established tissue cultures of poplar clones offer the potential for manipulation with enzymes involved in the lignin biosynthetic pathway such as caffeic acid O-methyltransferase and lignin peroxidases. Poplar clones (89M011, 89M066, Dursunbey 2) with the highest shoot regeneration efficiencies (70-100 %) were used for Agrobacterium transformation with antisense caffeic acid O-methyltransferase (pOMT8) and cationic peroxidase (Shpx6a) genes. Tobacco (Nicotiana tabacum) was used as a model control system. Constructs used in the study were obtained from forage legume Stylosanthes humilis and showed a high homology to corresponding caffeic acid O-methyltransferase (COMT) and peroxidase genes of poplar. Our results showed that antisense pOMT8 and Shpx6a peroxidase genes down regulated the activity of related enzymes. In the pOMT8 transgenics composition of lignin was changed, without changes in amount of lignin. However, in Shpx6a transgenics decreases in amount of lignin (up to 20 %) was observed. In the tobacco experiments with two types of transgenes (pOMT8 and Shpx6a) reduction of related enzymes activities and reduction of lignin amount was occurred in several transgenic plants

High frequency somatic embryogenesis in cotton

A highly reproducible system for efficient somatic embryogenesis was developed to regenerate plantlets from cotton ( Gossypium hirsutum L.) cultivars (Nazilli M-503 and Nazilli 143). Shoot apices, hypocotyls and nodes of 10-d-old seedlings were used as explants. High frequency (100%) embryogenic calli was initiated from all tested explants on Murashige and Skoog (1962) (MS) media supplemented with 1 g dm(-3) polyvinylpyrrolidone (PVP), 1 mg dm(-3) 6-benzylaminopurine (BAP), 0.5 mg dm(-3) kinetin for Nazilli M-503 and 1 g dm(-3) PVP, 2 mg dm(-3) BAP, 0.5 mg dm(-3) kinetin for Nazilli-143. Globular stage somatic embryos were produced 4 months after transfer to hormone-free MS medium supplemented with 1 g dm(-3) PVP. Subsequent subculture of globular embryos every 3 weeks on hormone-free MS medium led to the development of torpedo and cotyledonary stage embryos with the frequency of 75 and 83.2% from hypocotyl explants of Nazilli M-503 and Nazilli-143, respectively. Afterwards, mature somatic embryos were isolated and cultured on hormone-free MS medium for germination and development into plantlets. The highest germination frequency (42.9%) for Nazilli M-503 somatic embryos were obtained on hormone-free MS medium after 5 months with hypocotyl explants, whereas germination frequencies of Nazilli-143 embryos from hypocotyl, node and apex explants varied between 22 - 30%