SUMMARY The obligately biotrophic rust fungi are dependent on nutrient supply from their host plants. A cDNA library of infection structures of the rust fungus Uromyces fabae was used to identify a gene (UfAAT3) that encodes a protein with a high degree of sequence similarity to fungal amino acid permeases. The expression profile revealed by RT-PCR shows an up-regulation very early during rust development, with the highest level in haustoria and infected leaves. Heterologous expression of UfAAT3p in Xenopus oocytes revealed an amino acid permease energized by co-transport with protons and exhibiting a broad substrate specificity. Compared to the previously described U. fabae amino acid transporter (AAT1), which represented the highest transport activities for lysine and histidine, electrophysiological measurements with cRNA of UfAAT3-injected oocytes showed substrate preferences for leucine and the sulphur containing amino acids methionine and cysteine. The unique contribution of the amino acid permeases and their substrate affinities might be connected with the availability of amino acids in the leaf tissue. Thus, in order to compare the substrate profiles of AAT1p and UfAAT3p with the natural environment of U. fabae we analysed the amino acid concentration in the apoplastic space, in addition to that in extracts of Vicia faba leaves. The predominant free amino acids were asparagine, alanine, glutamine and glutamate. However, most amino acids were present at low concentrations (between 0.02 and 0.16 mm), including the preferred substrates of the U. fabae amino acid permeases AAT1p and UfAAT3p.

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Introduction Complex ankle fractures frequently include the posterior malleolus (PM). Despite advances in diagnostic and treatment strategies, PM fracture involvement still predisposes to worse outcomes. While not incorporated into the most common PM fracture classifications, the presence of an intercalary fragment (ICF) complicates treatment. This study aims to describe the incidence, morphology, and location of ICFs in PM fractures. Materials and methods A total of 135 patients with a mean age of 54.4 (SD ± 18.9) years and PM fractures were analyzed for the presence of an ICF. Patients with an ICF were compared to those without in terms of age, gender, and treatment received. Characteristics of the ICFs in terms of location and size were assessed. Furthermore, the presence of an ICF in relation to the PM fracture classification according to Haraguchi et al., Bartoníček/Rammelt et al., and Mason et al. was investigated. Results ICFs presented in 55 (41%) of the 135 patients. Patients with an ICF were younger, and the PM was more often operatively treated when compared to patients without an ICF. A posterolateral approach was used significantly more often in patients with an ICF. Almost all ICFs were found in the posterolateral (58%) and posterocentral (35%) regions. The majority of fragments were found in Bartoníček/Rammelt type 2 fractures, the most common fracture type. Bartoníček/Rammelt type 3 fractures had the highest relative frequency of ICFs. Conclusion ICFs are frequently found in PM fractures; however, they are not incorporated into any of the common classifications. They are generally found in younger patients and associated with more complex PM fractures. As they can complicate reduction of the main fragment and may require direct exposure to restore joint congruency, ICFs should be considered in PM fracture classifications. Due to their location, the majority of ICFs are able to be accessed using a posterolateral approach.