Plasmodesmal receptor-like kinases identified through analysis of rice cell wall extracted proteins

In plants, plasmodesmata (PD) are intercellular channels that function in both metabolite exchange and the transport of proteins and RNAs. Currently, many of the PD structural and regulatory components remain to be elucidated. Receptor-like kinases (RLKs) belonging to a notably expanded protein family in plants compared to the animal kingdom have been shown to play important roles in plant growth, development, pathogen resistance, and cell death. In this study, cell biological approaches were used to identify potential PD-associated RLK proteins among proteins contained within cell walls isolated from rice callus cultured cells. A total of 15 rice RLKs were investigated to determine their subcellular localization, using an Agrobacterium-mediated transient expression system. Of these six PD-associated RLKs were identified based on their co-localization with a viral movement protein that served as a PD marker, plasmolysis experiments, and subcellular localization at points of wall contact between spongy mesophyll cells. These findings suggest potential PD functions in apoplasmic signaling in response to environmental stimuli and developmental inputs

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Non-glandular trichomes in Lamiaceae and Verbenaceae species: morphological and histochemical features indicate more than physical protection

Non-glandular trichomes are traditionally known as acting in the physical protection of plants against biotic and abiotic stresses, forming a mechanical barrier against low humidity, high light intensity and temperatures, and feeding and oviposition activities of insects. However, detailed studies involving morphology, histochemistry and ultrastructure of these epidermal appendages are lacking. We characterised the morphology and histochemistry of the non-glandular trichomes in three Lamiaceae and four Verbenaceae species and evidenced their involvement in the production, storage and/or liberation of biologically active substances. Samples of leaves were prepared according to standard methods for scanning and transmission electron microscopy. Histochemical tests were performed using fresh material. The combination of structural and ultrastructural studies and histochemical techniques allowed us to verify that the non-glandular trichomes of all studied species are comprised by living cells able to act in the synthesis, storage and/or liberation of biologically active compounds. This is the first work showing the production of compounds in non-glandular trichomes in Lamiaceae and Verbenaceae species. Our observations indicate that more than a physical protection, the non-glandular trichomes of these species participate in the chemical interaction of the plants with the environment, supplementing the work of the typically glandular trichomes.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Department of Botany Univ. Estadual Paulista- UNESP Institute of Biosciences of Botucatu- IBBDepartment of Botany Univ. Estadual Paulista- UNESP Institute of Biosciences of Botucatu- IBBFAPESP: IC 2013/07428-