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Little is known about the physiological and molecular responses of leaves to aluminum (Al)-toxicity. Seedlings of Al-intolerant Citrus grandis and Al-tolerant Citrus sinensis were supplied daily with nutrient solution containing 0 mM (control) and 1.0 mM (Al-toxicity) AlCl 3 ·6H 2 O for 18 weeks. We found that Al-treatment only decreased CO 2 assimilation in C. grandis leaves, and that the Al-induced alterations of gene expression profiles were less in C. sinensis leaves than those in C. grandis leaves, indicating that C. sinensis seedlings were more tolerant to Al-toxicity than C. grandis ones. Al concentration was similar between Al-treated C. sinensis and C. grandis roots, but it was higher in Al-treated C. grandis stems and leaves than that in Al-treated C. sinensis stems and leaves. Al-treated C. sinensis seedlings accumulated relatively more Al in roots and transported relatively little Al to shoots. This might be responsible for the higher Al-tolerance of C. sinensis . Further analysis showed that the following several aspects might account for the higher Al-tolerance of C. sinensis , including: (a) Al-treated C. sinensis leaves had higher capacity to maintain the homeostasis of energy and phosphate, the stability of lipid composition and the integrity of cell wall than did Al-treated C. grandis leaves; (b) Al-triggered production of reactive oxygen species (ROS) and the other cytotoxic compounds was less in Al-treated C. sinensis leaves than that in Al-treated C. grandis leaves, because Al-toxicity decreased CO 2 assimilation only in C. grandis leaves; accordingly, more upregulated genes involved in the detoxifications of ROS, aldehydes and methylglyoxal were identified in Al-treated C. grandis leaves; in addition, flavonoid concentration was increased only in Al-treated C. grandis leaves; (c) Al-treated C. sinensis leaves could keep a better balance between protein phosphorylation and dephosphorylation than did Al-treated C. grandis leaves; and (d) both the equilibrium of hormones and hormone-mediated signal transduction were greatly disrupted in Al-treated C. grandis leaves, but less altered in Al-treated C. sinensis leaves. Finally, we discussed the differences in Al-responsive genes between Citrus roots and leaves. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, we report the sequences and characterization of the porcine integrin cDNAs encoding αv, β3, β6 and β8 subunits and compare them to those of other species. The coding sequences for the porcine αv, β3, β6 and β8 subunits were found to be 3141, 2289, 2367 and 2304 nucleotides in length, encoding 1046, 762, 788 and 767-amino-acid-residue protein, respectively. The porcine integrin αv, β3, β6 and β8 subunit shares common structural and functional elements with their counterparts from the other species. Phylogenetic trees showed that the porcine αv, β3, β6 and β8 were clustered into the Artiodactyla group, together with those of camels, sheep, and cattle, that are susceptible to FMDV infection. Real-time RT-PCR was used to investigate expression of the integrins αvβ3, αvβ6 and αvβ8 in different tissues of pigs in order to determine the role of these receptors in tissue tropism. Expression analysis showed that αvβ6 and αvβ8 mRNA expression were detected at high levels in tissues known to support replication of FMDV. Tissue distribution pattern of αvβ3 mRNA seems to be unrelated to the known tissue tropism of FMDV. This study provided the first data of porcine integrins for the further studies of the FMDV pathogenesis in pigs. [Copyright &y& Elsevier]

Abstract: Four members of the αv integrin family of cellular receptors, αvβ1, αvβ3, αvβ6, and αvβ8, have been identified as receptors for foot-and-mouth disease virus (FMDV) in vitro, and integrins are believed to be the receptors used to target epithelial cells in the infected animals. To analyse roles of the αv integrins from a susceptible species as viral receptors, we have cloned sheep αv, β1, and β6 integrin cDNAs and compared them to those of other species. The coding sequences for sheep integrin αv, β1, and β6 were found to be 3147, 2397, and 2364 nuclotides in length, encoding 1048, 798, and 787 amino acids, respectively. The sheep αv, β1, and β6 subunits share many structural features including ligand binding domain and cysteine-rich region with homologues of other species. Phylogenetic trees and similarity analyses showed the close relationship of integrin genes among sheep, pigs, cattle and Bactrian camels that are susceptible to FMDV infection, which were distinct from the order Rodentia, Primates, Perissodactyla, Carnivora, Galliformes. We postulate that host tropism of FMDV may be related to divergence in integrin subunits among different species. [Copyright &y& Elsevier]