Antioxidant profiles and selected parameters of primary metabolism in Physalis ixocarpa hairy roots transformed by two Agrobacterium rhizogenes strains

We compared the biochemical profiles of Physalis ixocarpa hairy roots transformed with Agrobacterium rhizogenes ATCC and A4 strains with non-transformed root cultures. The studied clones of A4- and ATCC-induced hairy roots differed significantly; the latter showed greater growth potential and greater ability to produce secondary metabolites (tropane alkaloids) and to biotransform hydroquinone to arbutin. We compared glucose content, alanine and aspartate aminotransferase activity, and L-phenylalanine ammonia-lyase activity. We analyzed markers of prooxidant/antioxidant homeostasis: catalase, ascorbate peroxidase, oxidase, glutathione peroxidase and transferase activity, and the levels of ascorbate, glutathione, tocopherol and lipid peroxidation. We found that transformation induced strain-specific regulation, including regulation based on redox signals, determining the rate of allocation of carbon and nitrogen resources to secondary metabolism pathways. Our results provide evidence that A. rhizogenes strain-specific modification of primary metabolites contributed to regulation of secondary metabolism and could determine the ability of P. ixocarpa hairy root clones to produce tropane alkaloids and to convert exogenously applied hydroquinone to pharmaceutically valuable arbutin. Of the studied parameters, glucose content, L-phenylalanine ammonia-lyase activity and alanine aminotransferases activity may be indicators of the secondary metabolite-producing potential of different P. ixocarpa hairy root clones

Asymbiotic germination, seedling development and plantlet propagation of Encyclia aff. oncidioides - an endangered orchid

In order to estimate the best germination conditions of Encyclia aff. oncidioides seeds, five different media (Fast, Knudson C modified by Vajrabhaya, Murashige and Skoog, PB2 and modified Vacin and Went) with different concentrations of plant growth regulators such as benzyladenine (BA), naphthaleneacetic acid (NAA) and gibberellic acid (GA3) were tested. No beneficial effect was observed when BA and NAA were applied to the germination medium and GA3 inhibited germination. The effect of light, activated charcoal, coconut water and casein hydrolysate on seed germination was also studied. The growth rate of seedlings on three different media supplemented with activated charcoal and plant growth regulators was checked. The applied plant growth regulators had no beneficial effect on the further growth of seedlings. Fast and PB2 media with 0.2% activated charcoal proved to be the best for E. aff. oncidioides seed germination, seedling development and plantlet propagation

Synthesis of antimicrobial silver nanoparticles through a photomediated reaction in an aqueous environment

Rafał Banasiuk,1,* Joanna E Frackowiak,2,* Marta Krychowiak,1 Marta Matuszewska,1 Anna Kawiak,1 Magdalena Ziabka,3 Zofia Lendzion-Bielun,4 Magdalena Narajczyk,5 Aleksandra Krolicka1 1Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, 2Department of Pathophysiology, Medical University of Gdansk, Gdansk, 3Faculty of Materials Science and Ceramics, Department of Ceramics and Refractories, AGH-University of Science and Technology, Kraków, 4Institute of Chemical and Environment Engineering, West Pomeranian University of Technology, Szczecin, 5Faculty of Biology, Laboratory of Electron Microscopy, University of Gdansk, Gdansk, Poland *These authors contributed equally to this work Abstract: A fast, economical, and reproducible method for nanoparticle synthesis has been developed in our laboratory. The reaction is performed in an aqueous environment and utilizes light emitted by commercially available 1 W light-emitting diodes (λ =420 nm) as the catalyst. This method does not require nanoparticle seeds or toxic chemicals. The irradiation process is carried out for a period of up to 10 minutes, significantly reducing the time required for synthesis as well as environmental impact. By modulating various reaction parameters silver nanoparticles were obtained, which were predominantly either spherical or cubic. The produced nanoparticles demonstrated strong antimicrobial activity toward the examined bacterial strains. Additionally, testing the effect of silver nanoparticles on the human keratinocyte cell line and human peripheral blood mononuclear cells revealed that their cytotoxicity may be limited by modulating the employed concentrations of nanoparticles. Keywords: antimicrobial activity, green synthesis, nanocubes, nanospheres&nbsp

Chitinase Chi1 from Myceliophthora thermophila C1, a Thermostable Enzyme for Chitin and Chitosan Depolymerization

A thermostable Chitinase Chi1 from Myceliophthora thermophila C1 was homologously produced and characterized. Chitinase Chi1 shows high thermostability at 40 °C (>140 h 90% activity), 50 °C (>168 h 90% activity), and 55 °C (half-life 48 h). Chitinase Chi1 has broad substrate specificity and converts chitin, chitosan, modified chitosan, and chitin oligosaccharides. The activity of Chitinase Chi1 is strongly affected by the degree of deacetylation (DDA), molecular weight (Mw), and side chain modification of chitosan. Chitinase Chi1 releases mainly (GlcNAc)2 from insoluble chitin and chitooligosaccharides with a polymerization degree (DP) ranging from 2 to 12 from chitosan, in a processive way. Chitinase Chi1 shows higher activity toward chitin oligosaccharides (GlcNAc)4−6 than toward (GlcNAc)3 and is inactive for (GlcNAc)2. During hydrolysis, oligosaccharides bind at subsites −2 to +2 in the enzyme’s active site. Chitinase Chi1 can be used for chitin valorisation and for production of chitin- and chito-oligosaccharides at industrial scale

Salicylic acid can reduce infection symptoms caused by Dickeya solani in tissue culture grown potato (Solanum tuberosum L.) plants

The potential for control of Dickeya solani infections in potato by elicitation of in vitro grown potato plants with salicylic acid (SA) was investigated by selective plating and confocal laser scanning macroscopy (CLSM). In replicated experiments potato plants grown on medium supplemented with 25 or 50 μM of SA were evaluated for the phytotoxic effects. Potato plants grown on medium supplemented with SA and inoculated with GFP-tagged D. solani were investigated for blackleg development and colonization of potato plants by the bacteria. Three days after inoculation, colonization of roots by D. solani was observed in 100 % control plants grown on medium without SA but not in plants grown on medium supplemented with 50 μM SA. After 14 days, 100 % of control plants showed severe disease symptoms, whereas plants grown on medium supplemented with 50 μM SA and inoculated with bacteria did not express any symptoms. After 14 days bacteria were found inside 100 % stems of control plants in densities of ca. 103–104 cfu g−1 and inside ca. 10–15 % stems of plants treated with 50 μM SA in densities similar to these in the control plants. The GFP-tagged bacteria were macroscopically detected on the surface of the roots of control plants but not on the surface of the plants treated with 50 μM SA 14 days after inoculation. The implications of SA treatments on plant fitness and disease development are discussed.</p