We determined the sequence of the intergenic spacer (IGS) 1 region, which is located between the 26S and 5S rRNA genes, in 25 species of the genus Trichosporon. IGS 1 sequences varied in length from 195 to 719 bp. Comparative sequence analysis suggested that the divergence of IGS 1 sequences has been greater than that of the internal transcribed spacer regions. We also identified five genotypes of T. asahii, which is a major causative agent of deep-seated trichosporonosis, based on the IGS 1 sequences of 43 strains. Most of the isolates that originated in Japan were of genotype 1, whereas the American isolates were of genotype 3 or 5. Our results suggest that analysis of IGS regions provides a powerful method to distinguish between phylogenetically closely related species and that a geographic substructure may exist among T. asahii clinical isolates.Fungal rRNA genes are tandemly repeated, with each repeat encoding 18S (small-subunit), 5.8S, and 26S (large-subunit) genes. Two other regions exist in each repeat: the internal transcribed spacer (ITS) region and the intergenic spacer (IGS) region (Fig. 1). Ribosomal DNA (rDNA) has been widely utilized for molecular systematics and the identification of microorganisms. The D1/D2 regions of 26S and ITS sequences have been used mainly to identify pathogenic fungi. At present, the 26S rDNA sequences of almost all yeasts, including nonpathogenic species, have been determined (3,7,8). The analysis of ITS sequences has been carried out mainly for pathogenic yeast species (1,5,9,10,16,19). Peterson and Kurtzman (13) and Sugita et al. (16) demonstrated that a single species showed less than 1% dissimilarity in either the ITS region or D1/D2 26S rDNA. However, these sequence analyses are sometimes incapable of distinguishing between phylogenetically closely related species, such as the three varieties of Cryptococcus neoformans. Although three varieties within a single species can be distinguished for each varietal level by ITS sequence analysis, the distinction is based on differences of only three or four nucleotides (20). Recently, Diaz et al. (2) and Sugita et al. (17) demonstrated that three varieties of C. neoformans were more clearly distinguished by analysis of IGS 1 and IGS 2 sequences than by ITS sequence analysis. Therefore, IGS sequence analysis appears to be a powerful tool for differentiating between phylogenetically very closely related species.

SummaryEndoglin (ENG)/CD105 is an essential endothelial cell co-receptor of the transforming growth factor β (TGF-β) superfamily, mutated in hereditary hemorrhagic telangiectasia type 1 (HHT1) and involved in tumor angiogenesis and preeclampsia. Here, we present crystal structures of the ectodomain of human ENG and its complex with the ligand bone morphogenetic protein 9 (BMP9). BMP9 interacts with a hydrophobic surface of the N-terminal orphan domain of ENG, which adopts a new duplicated fold generated by circular permutation. The interface involves residues mutated in HHT1 and overlaps with the epitope of tumor-suppressing anti-ENG monoclonal TRC105. The structure of the C-terminal zona pellucida module suggests how two copies of ENG embrace homodimeric BMP9, whose binding is compatible with ligand recognition by type I but not type II receptors. These findings shed light on the molecular basis of the BMP signaling cascade, with implications for future therapeutic interventions in this fundamental pathway.

Malassezia species are considered to be one of the exacerbating factors in atopic dermatitis (AD). During examination of the cutaneous colonization of Malassezia species in AD patients, we found a new species on the surface of the patients' skin. Analysis of ribosomal DNA sequences suggested that the isolates belonged to the genus Malassezia. They did not grow in Sabouraud dextrose agar but utilized specific concentrations of Tween 20, 40, 60, and 80 as a lipid source. Thus, we concluded that our isolates were new members of the genus Malassezia and propose the name Malassezia dermatis sp. nov. for these isolates.Malassezia species are known causative factors in pityriasis versicolor, seborrheic dermatitis (SD), and atopic dermatitis (AD) (3). In the last decade, research has focused primarily on isolating Malassezia strains and detecting specific immunoglobulin E (IgE) antibodies from patients (9,13,14,26). A comparison of the isolation rates of Malassezia species from the skin of AD patients and healthy control subjects detected a significantly higher rate for patients than for healthy subjects (8). AD patients had specific IgE antibodies against Malassezia, while healthy subjects did not. In recent years, studies have increasingly been directed towards analyzing how the cutaneous microflora at the species level are related to each disease type (pityriasis versicolor, SD, and AD) (1,6,7,12,16). We previously compared the distribution of Malassezia species in skin lesions of AD patients and in healthy subjects using a nonculture method (nested PCR) that is not affected by the isolating medium (21). Of the seven members of the genus Malassezia, Malassezia globosa and M. restricta were the species most commonly associated with AD, while M. obtusa and M. pachydermatis were not detected in AD. In our survey of cutaneous Malassezia microflora, we isolated new Malassezia species from several patients with AD. In this paper, we propose a new species, M. dermatis, for these isolates. MATERIALS AND METHODSMalassezia isolates. Nineteen AD outpatients at Juntendo University Hospital were included in the study. To obtain samples, OpSite transparent dressings (3 by 7 cm; Smith and Nephew Medical Ltd., Hull, United Kingdom) were applied to skin lesions (erosive, erythematous, and lichenoid) on the scalp, back, and nape of the neck of AD patients. Samples were then transferred onto Leeming and Notman agar (LNA) (10.0 g of polypeptone, 5.0 g of glucose, 0.1 g of yeast extract, 8.0 g of ox gall, 1.0 mg of glycerol, 0.5 g of glycerol stearate, 0.5 mg of Tween 60, 10 ml of cow's milk [whole fat], and 12.0 g of agar per liter) plates containing 50 l of chloramphenicol (Sankyo, Tokyo, Japan) and incubated at 32°C for 2 weeks.Direct DNA sequencing of rRNA genes of the isolates. Yeast isolates recovered from LNA medium were identified by analysis of rRNA gene sequences. Nuclear DNA of the isolates was extracted by the method of Makimura et al. (15). The D1 and D2 regions of 26S ribosomal DNA (rDNA) and internal transcribed spacer (IT...

We compared cutaneous colonization levels of Malassezia species in patients with AD and healthy subjects using nested PCR. Malassezia-specific DNA was detected in all 32 of the patients with AD. M. globosa and M. restricta were detected in approximately 90 % of these patients, with M. furfur and M. sympodialis being detected in approximately 40% of the cases. In healthy subjects, Malassezia DNA was detected in 78% of the samples, M, globosa, M. restricta and M. sympodialis were detected at frequencies ranging from 44 to 61%, and M. furfur was found in 11% of healthy subjects.Our results suggest that M. furfur, M. globosa, M. restricta and M. sympodialis are common inhabitants of the skin of both AD patients and healthy subjects, while the skin microflora of patients with AD shows more diversity than that of healthy subjects.

Hermaphroditic organisms avoid inbreeding by a system of self-incompatibility (SI). A primitive chordate (ascidian) Ciona intestinalis is an example of such an organism, but the molecular mechanism underlying its SI system is not known. Here, we show that the SI system is governed by two gene loci that act cooperatively. Each locus contains a tightly linked pair of polycystin 1-related receptor (s-Themis) and fibrinogen-like ligand (v-Themis) genes, the latter of which is located in the first intron of s-Themis but transcribed in the opposite direction. These genes may encode male- and female-side self-recognition molecules. The SI system of C. intestinalis has a similar framework to that of flowering plants but utilizing different molecules.