As a first step toward the exploitation of the disaccharide trehalose as a stress-protective and preservative agent in plants, we engineered trehalose biosynthesis in tobacco (Nicotiana tabacum) and potato (Solanum tuberosum) by introducing the otsA and otsB genes from Escherichia coli, which encode trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase, respectively. In leaves of transgenic tobacco plants, very low levels of trehalose accumulation were obtained (0.11 mg g-1 fresh weight), whereas in transgenic potato tubers, no trehalose accumulated at all. Plant trehalase activity was shown to affect the accumulation of trehalose in these plants. An increase in trehalose accumulation, up to 0.41 and 4.04 mg g-1 fresh weight in tobacco leaves and potato microtubers, respectively, was noted when the potent trehalase inhibitor validamycin A was added to in vitro plants and to hydroponically grown greenhouse plants. Stunted growth and the formation of lancet-shaped leaves by trehalose-accumulating tobacco plants suggest a negative effect of trehalose biosynthesis on N. tabacum development. It is surprising that experiments with wild-type plants cultured in the presence of validamycin A indicate that, despite current belief, the capacity to synthesize trehalose may not be restricted to primitive phyla of vascular plants and certain “resurrection plants,” but may exist throughout the angiosperms.

Different isoforms of chitinases and @-1,3-glucanases of tobacco (Nicotiana fabacum cv Samsun NN) were tested for their antifungal activities. l h e class I, vacuolar chitinase and @-1,3-gIucanase isoforms were the most active against Fusarium solani germlings, resulting in lysis of the hyphal tips and in growth inhibition. In addition, we observed that the class I chitinase and @-1,3-glucanase acted synergistically. The class II isoforms of the two hydrolases exhibited no antifungal activity. However, the class II chitinases showed limited growth inhibitory activity in combination with higher amounts of class I @-1,3-glucanase. The class II @-1,3-glucanases showed no inhibitory activity in any combination. In transgenic tobacco plants producing modified forms of either a class I chitinase or a class I @-1,3-glucanase, or both, these proteins were targeted extracellularly. Both modified proteins lack their Cterminal propeptide, which functions as a vacuolar targeting signal. Extracellular targeting had no effect on the specific activities of the chitinase and @-1,3-glucanase enzymes. Furthermore, the extracellular washing fluid (EF) from leaves of transgenic plants expressing either of the secreted class I enzymes exhibited antifungal activity on f. solani germlings in vitro comparable to that of the purified vacuolar class I proteins. Mixing EF fractions from these plants revealed synergism in inhibitory activity against F. solani; the mixed fractions exhibited inhibitory activity similar to that of EF from plants expressing both secreted enzymes.

A new class of tobacco chitinases homologous to bacterial exo-chitinases displays antifungal activity Melchers, L.S.; Apotheker-de Groot, M.; van der Knaap, J.A.; Ponstein, A.P.; Sela-Buurlage, M.B.; Bol, J.F.; Cornelissen, B.J.C.; van den Elzen, P.J.M.; Linthorst, H.J.M. Published in:Plant Journal Link to publication Citation for published version (APA):Melchers, L. S., Apotheker-de Groot, M., van der Knaap, J. A., Ponstein, A. P., Sela-Buurlage, M. B., Bol, J. F., ... Linthorst, H. J. M. (1994). A new class of tobacco chitinases homologous to bacterial exo-chitinases displays antifungal activity. Plant Journal, 5, 469-480. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 13 May 2018The Plant Joumal (1994) Two related chitinsse class V proteins of 41 and 43 kDa were purified from Samsun NN tobacco leaves inoculated with tobacco mosaic virus. The proteins were purified by Chelating Suparose chromatography and gel filtration. In vitro assays demonstrated that class V chitinaeas have endo-chitinase activity and exhibit antifungal activity toward Trichoderma viride and Alternaria radicina. In addition, it was shown that class V chitlnase acts synergistically with tobacco class I 1~-l,3-glucanase agalnat Fusarlum solani germlings.

SummaryIn a search for novel plant-derived antimicrobial proteins, we screened extracts from salicylic acid (SA)-treated lettuce and sun¯ower leaves. These extracts displayed very potent antimicrobial activity against a set of phytopathogens. Characterisation of these extracts revealed that in both extracts, proteins of approximately 60 kDa were responsible for the antimicrobial activity. Further characterisation of these proteins and cloning of the respective cDNAs revealed close homology to a range of (plant) oxidases. Dissection of the enzymatic activity of both proteins revealed them to be carbohydrate oxidases (Helianthus annuus carbohydrate oxidase (Ha-CHOX) and Lactuca sativa carbohydrate oxidase (Ls-CHOX)) with broad substrate speci®city and with hydrogen peroxide (H 2 O 2 ) as one of the reaction products. The sun¯ower transcript, in addition to being SA inducible, was also inducible by fungal pathogens but not by ethylene and jasmonate. To determine whether Ha-CHOX plays a role in pathogen defence, it was transformed into tobacco and the effect of resistance to Pectobacterium carotovorum ssp. carotovorum was examined. Transgenic plants overexpressing Ha-CHOX displayed enhanced resistance to infection by this pathogen, and the resistance level was proportional to enzyme expression.

BackgroundAnxiety disorders are one of the most diagnosed mental health disorders. Common treatment consists of cognitive behavioral therapy and pharmacotherapy. In clinical practice, also art therapy is additionally provided to patients with anxiety (disorders), among others because treatment as usual is not sufficiently effective for a large group of patients. There is no clarity on the effectiveness of art therapy (AT) on the reduction of anxiety symptoms in adults and there is no overview of the intervention characteristics and working mechanisms.MethodsA systematic review of (non-)randomised controlled trials on AT for anxiety in adults to evaluate the effects on anxiety symptom severity and to explore intervention characteristics, benefitting populations and working mechanisms. Thirteen databases and two journals were searched for the period 1997 –October 2017. The study was registered at PROSPERO (CRD42017080733) and performed according to the Cochrane recommendations. PRISMA Guidelines were used for reporting.ResultsOnly three publications out of 776 hits from the search fulfilled the inclusion criteria: three RCTs with 162 patients in total. All studies have a high risk of bias. Study populations were: students with PTSD symptoms, students with exam anxiety and prisoners with prelease anxiety. Visual art techniques varied: trauma-related mandala design, collage making, free painting, clay work, still life drawing and house-tree-person drawing. There is some evidence of effectiveness of AT for pre-exam anxiety in undergraduate students. AT is possibly effective in reducing pre-release anxiety in prisoners. The AT characteristics varied and narrative synthesis led to hypothesized working mechanisms of AT: induce relaxation; gain access to unconscious traumatic memories, thereby creating possibilities to investigate cognitions; and improve emotion regulation.ConclusionsEffectiveness of AT on anxiety has hardly been studied, so no strong conclusions can be drawn. This emphasizes the need for high quality trials studying the effectiveness of AT on anxiety.