Is callose a barrier for lead ions entering Lemna minor L. root cells?

Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained results showed that Pb induced callose synthesis in L. minor roots, but it was not deposited regularly in all tissues and cells. Callose occurred mainly in the protoderm and in the centre of the root tip (procambial central cylinder). Moreover, continuous callose bands, which could form an efficient barrier for Pb penetration, were formed only in the newly formed and anticlinal cell walls (CWs); while in other CWs, callose formed only small clusters or incomplete bands. Such an arrangement of callose within root CWs inefficiently protected the protoplast from Pb penetration. As a result, Pb was commonly present inside the root cells. In the light of the results, the barrier role of callose against metal ion penetration appears to be less obvious than previously believed. It was indicated that induction of callose synthesis is not enough for a successful blockade of the stress factor penetration. Furthermore, it would appear that the pattern of callose distribution has an important role in this defence strategy

Electrocatalytic hydrogen redox chemistry on gold nanoparticles

Electrocatalytic proton reduction leading to the formation of adsorbed molecular hydrogen on gold nanoparticles of 1-3 and 14-16 nm diameter stabilized by 1-mercapto-undecane-11-tetra(ethyleneglycol) has been demonstrated by cyclic voltammetry using a hanging mercury drop electrode. The nanoparticles were adsorbed to the electrode from aqueous dispersion and formed robust surface layers transferrable to fresh base electrolyte solutions. Unique electrocatalytic proton redox chemistry was observed that has no comparable counterpart in the electrochemistry of bulk gold electrodes. Depending on size, the nanoparticles have a discrete number of electrocatalytically active sites for the two-electron/two-proton reduction process. The adsorbed hydrogen formed is oxidized with the reverse potential sweep. These findings represent a new example of qualitative different behavior of nanoparticles in comparison with the corresponding bulk material.Fil: Brust, Mathias. University of Liverpool; Reino UnidoFil: Gordillo, Gabriel Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentin

Inclusive national governance and trafficked women in Australia: otherness and local demand

Trafficked women are used and consumed in different ways and by different users in Australia. They are used by the traffickers and by the consumer of the destination country. They are used as prosecutorial tools by the national criminal justice agents. They are used by the national politicians to pursue border control policy objectives and to be seen as abiding by international protocols. In all these uses, the identity of the trafficked woman is formed and shaped to fit the users’ need. However, these women’s otherness and abjection is constantly maintained and reinforced. They are used as a commodity. Meanwhile, the discussion on the demand side, and the consequent responsibility of the destination country, is virtually omitted. This paper will raise the question of how the sociolegal analysis and discourse would evolve if a literal interpretation of trafficking women as a commodity was taken into account, exploring an international trade approach. The social construction of trafficked women as a commodity has been identified and criticised by academic scholars, NGOs’ and UN’s rapporteurs. By pursuing this line of approach, the destination country is forced to take more responsibility for how the woman is demanded within its territory. As a consequence of this international trade approach, the State should deliver equality and non-discrimination. Rather than being a cynical application of a trade framework to trafficked women, this approach aims to highlight the paradox of such a situation in legal terms. It is highlighted that approaching trafficked women from this legal and jurisprudential way may offer more possibilities to expand their claims against the State. Currently, in Australia, when a trafficked woman is located by the State, she would attract limited and temporal rights, her being the ‘other’ as well as an abject entity remains, notwithstanding the fact the she was imported because there is a demand within the territory.Marinella Marmo and Rebecca LaForgi