The family of aquaporins, also called water channels or major intrinsic proteins, is characterized by six transmembrane domains that together facilitate the transport of water and a variety of low molecular weight solutes. They are found in all domains of life, but show their highest diversity in plants. Numerous studies identified aquaporins as important targets for improving plant performance under drought stress. The phylogeny of aquaporins is well established based on model species like Arabidopsis thaliana, which can be used as a template to investigate aquaporins in other species. In this study we comprehensively identified aquaporin encoding genes in tomato (Solanum lycopersicum), which is an important vegetable crop and also serves as a model for fleshy fruit development. We found 47 aquaporin genes in the tomato genome and analyzed their structural features. Based on a phylogenetic analysis of the deduced amino acid sequences the aquaporin genes were assigned to five subfamilies (PIPs, TIPs, NIPs, SIPs and XIPs) and their substrate specificity was assessed on the basis of key amino acid residues. As ESTs were available for 32 genes, expression of these genes was analyzed in 13 different tissues and developmental stages of tomato. We detected tissue-specific and development-specific expression of tomato aquaporin genes, which is a first step towards revealing the contribution of aquaporins to water and solute transport in leaves and during fruit development.
Liquid crystal (LC) provides a suitable platform to exploit structural motions of molecules in a condensed phase. Amplification of the structural changes enables a variety of technologies not only in LC displays but also in other applications. Until very recently, however, a practical use of LCs for removable adhesives has not been explored, although a spontaneous disorganization of LC materials can be easily triggered by light-induced isomerization of photoactive components. The difficulty of such application derives from the requirements for simultaneous implementation of sufficient bonding strength and its rapid disappearance by photoirradiation. Here we report a dynamic molecular LC material that meets these requirements. Columnar-stacked V-shaped carbon frameworks display sufficient bonding strength even during heating conditions, while its bonding ability is immediately lost by a light-induced self-melting function. The light-melt adhesive is reusable and its fluorescence colour reversibly changes during the cycle, visualizing the bonding/nonbonding phases of the adhesive.
Flapping fluorophores (FLAP) have been developed as a new series of molecular viscosity probes that show polarity-independent ratiometric fluorescence properties.
Marine mammals bioaccumulate various environmental contaminants such as organochlorines (OCs), which biomagnify via the food web. While the immunomodulatory effects of individual OCs have been studied, the effects of mixtures are not well understood. The immunomodulatory effects of polychlorinated biphenyl (PCB) 138, 153, 169, and 180 as well as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and all possible mixtures were examined in marine mammals and mice. Lymphocyte proliferation was significantly modulated by OCs in all species tested, mostly by non-coplanar PCBs, as shown using regression analyses. Correlation analyses showed significant correlations (interpreted as additive effects) between OCs in mice, killer whales, and Steller sea lions. Nonadditive synergistic and antagonistic interactions between OCs were detected in most of the species tested. Toxic equivalency (TEQ) values used for OC toxicity assessment failed to predict the immunomodulatory effects measured in mice and marine mammals. The commonly used mouse model failed to predict immunomodulatory effects in other species. Clustering data suggested that phylogeny does not predict toxicity of OCs. Overall, our data suggest the presence of species-specific sensitivities to different mixtures, in which OCs interactions may be complex and that may exert their effects through dioxinlike or dioxin-independent pathways. Lastly, lymphocyte proliferation, an important part of adaptive immunity, was significantly modulated in mice and marine mammals, suggesting the possibility of increased susceptibility to diseases. These findings will be useful to better characterize the risk associated with OC exposure and possibly lead to new conservation and management strategies.
Contaminant-induced immunosuppression by organochlorines (OC), particularly polychlorinated biphenyls (PCBs), has been suspected as a cofactor in the deaths of thousands of marine mammals. One important innate defense mechanism is phagocytosis, the ability of cells to ingest extracellular macromolecules. The present study was aimed at characterizing the immunomodulatory potential of representative OCs on phagocytosis in bottlenose dolphins and beluga whales. The ability of peripheral blood leukocytes to engulf fluorescent microspheres was evaluated using flow cytometry. The immunomodulatory effects of three non-coplanar PCB congeners, 138, 153, and 180, one coplanar PCB, 169, and 2,3,7,8-TCDD and all possible mixtures (26) were tested upon in vitro exposure. In both species, all mixtures containing at least two non-coplanar PCBs significantly reduced both neutrophil and monocyte phagocytosis, with effects more marked in dolphins than in belugas. Coplanar OCs, on their own or when added to non-coplanar congeners, did not further modulate phagocytosis, suggesting an Ah receptor-independent mechanism. Concentration-response experiments with individual congeners further demonstrated a non-coplanar PCB-induced suppression of phagocytosis, while coplanar congeners produced no consistent effects. Our results suggest simple additive interactions of chemicals in a mixture. However, calculation of toxic equivalency (TEQs) failed to predict the experimentally induced immunomodulatory effects of OCs on dolphin and beluga phagocytosis, confirming the Ah receptor-independent nature of the effects on phagocytosis. Overall, our results suggest that non-AhR mechanisms may explain one facet of immunotoxicity (phagocytosis), something that is not captured using the TEQ approach. This is the first report demonstrating the immunomodulatory effects of OCs on dolphin and beluga phagocytosis, and the first overall demonstration of immunomodulatory effects on phagocytosis mediated specifically by non-coplanar PCBs.
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