Ascorbate oxidase (AO, EC 1.10.3.3) catalyzes the oxidation of ascorbate (AsA) to yield water. AO overexpressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. Previous studies have suggested a role for AO as a regulator of oxygen content in photosynthetic tissues. For the first time we show here that the expression of a Lotus japonicus AO gene is induced in the symbiotic interaction with both nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi. In this framework, high AO expression is viewed as a possible strategy to down-regulate oxygen diffusion in root nodules, and a component of AM symbiosis. A general model of AO function in plants is discussed.

The functional role of ascorbate oxidase (AO; EC 1.10.3.3) has never been fully explained so far, due to the difficulties in understanding the presence of an enzyme specifically oxidizing ascorbate with no obvious advantage, and the apparent disadvantage of lowering plant stress resistance as a consequence of ascorbate consumption. Here we suggest a complete change of perspective, by proposing an essential role of AO as a modulator of both ascorbate and oxygen content, with relevant implications related to signaling. By affecting the overall redox state, AO is actually involved in redox regulation in the extracellular matrix. In addition, AO can contribute to creating a hypoxic microenvironment, especially relevant in the maintenance of meristem identity and the establishment of mutualistic plant-microbe interactions. We also hypothesize the possible involvement of AO in the activation of a signaling cascade analogous to the mechanism of prolyl hydroxylases/Hypoxia Inducible Factors in animals

The filamentous chlorophyte Chaetomorpha linum (Muller) Kutzing can stand wide changes in salinity occuring in brackish and estuarine waters In an attempt to characterize C linum adaptation, a NaCl-inducecl ascorbate oxidase (AAO) activity was identified and partially characterized Immunogold-transmission electron microscopy analysis showed AAO labelling in the cytosol, walls and chloroplasts of C linum cells, whereas in angiosperms this enzyme is almost exclusively confined to the extracellular matrix The possible function of AAO in adaptation and functional evolution of its cellular location is discussed.

Post-embryonic root growth relies on the proliferative activity of the root apical meristem (RAM), consisting, in part, of cells with juvenile characteristics (stem cells). It is generally, but erroneously held that the RAM indefinitely produces new cells throughout the lifespan of a plant, resulting in indeterminate root growth. On the contrary, convincing data, mainly from the lab of Thomas L. Rost, show in all species analyzed so far, including Arabidopsis, that RAM organization changes over time in parallel with both a cessation of the production of new cells, and a consequent reduction in root growth, even under optimal conditions. In addition, RAM organization evolved to become highly plastic and dynamic in response to environmental triggers (e.g. water and nutrient availability, pollutants). Under unfavourable conditions, the RAM is rapidly reorganized, and, as a result of the cessation of new cell production at the root tip, root growth is altered, and lateral root production is enhanced, thus providing the plant additional strategies to overcome the stress. It is now becoming increasingly clear that this environment-responsive developmental plasticity is linked to reactive oxygen/nitrogen species, antioxidants, and related enzymes, which form part of a complex signalling module specifically operating in the regulation of RAM functioning, in strict relationship with hormonal control of root development exerted by auxin, gibberellins and cytokinins. In turn, such redox/hormone crosstalk regulates gene expression.

A wide range of teaching strategies have been employed to improve the effectiveness of STEM education. In some studies, music has been used as a tool to help memorizing scientific concepts. However, music (without lyrics) can also be considered in itself as an interesting way to explore and explain the complexity of both natural and artificial structures, and a way to guide learners of every age towards the deep understanding of the difficult concept of molecular order. For this purpose, we developed a scientifically based "decryption" method to assign a given sound to single atoms within crystals. All sound parameters (pitch, duration, timbre, and dynamics) are based on physical and chemical properties of the atoms involved in the structure. The "crystal soundtrack" is accompanied by animations highlighting the position of each atom considered in its context. Possible applications of this novel educational approach range from chemistry (atomic structures, the periodic table, the octet rule), to Earth sciences (the structure of natural crystals), material sciences (artificial structures), and biology (macromolecules such as sugars and nucleic acids). Musical examples will be presented and discussed.

The E-MoVe! project (Evolution of the Plant World) aims at disseminating information on biological evolution. The project, funded by the Italian Ministry of Education, includes a permanent exhibition located in the Botanical Garden Museum of the University of Bari (Italy), and the production of interactive games. Three interactive games for teaching plant evolution have been designed so far: 1. The time machine. The player travels in time to see plants from the past ages. Using a drag-and-drop approach, the player is guided through six different levels of the game, each dealing with a major group of photosynthetic organisms (Cyanobacteria; Eukaryotic Algae; Bryophytes; Pteridophytes; Gymnosperms, and Angiosperms). After completing each level, a summary of the features of each group is given. A seventh level (accessible only after completing the six levels above) introduces the player to a possible future scenario, suggesting the appearance of novel plant species able to solve major environmental issues. 2. Plant evolution and biodiversity. The player associates the definition of a given photosynthetic organism with its picture and scientific name. Also in this game six different levels are given. The final screenshot of each level describes more in details the reasons underlying the evolutionary success of each group. 3. Gene expression and flower morphology. The player, by regulating the expression of genes involved in the determination of flower shape (ABC model), interacts with the development of the flowers of Arabidopsis thaliana (L.) Heyn. The validation of the games has been carried out by interviewing students and school teachers. The results obtained showed broad interest in such novel teaching tools. The games will be made freely available to schools and scientific institutions worldwide. The English versions of all three games are currently in preparation.

preliminary information is reported on the historical Herbarium collected in the second part of the XiX century by the apulian botanist Giuseppe De Nicolò. the Herbarium consists of about 6,000 specimens, and witnesses an active collaboration between De Nicolò and the major botanists of his time, including Gussone, Pedicino, and Gasparrini.

A large number of studies have investigated the relationship between different forms of abiotic stress and antioxidants. However, misconceptions and technical flaws often affect studies on this important topic. Reactive oxygen species (ROS) generated under stress conditions should not be considered just as potential threats, because they are essential components of the signaling mechanism inducing plant defenses. Similarly, the complexity of the antioxidant system should be considered, to avoid misleading oversimplifications. Recent literature is discussed, highlighting the importance of accurate experimental setups for obtaining reliable results in this delicate field of research. A tentative ‘‘troubleshooting guide’’ is provided to help researchers interested in improving the quality of their work on the role of antioxidants in plant stress resistance. Significant advancements in the field could be reached with the development of antioxidomics, defined here as a new branch of research at the crossroads of other disciplines including metabolomics and proteomics, studying the complex relationship among antioxidants and their functions.