Secreted Hydrolytic and Haemolytic Activities of Malassezia Clinical Strains

Mycopathologia - Malassezia yeasts are opportunistic pathogens associated with a number of skin diseases in animals and humans. The free fatty acids released through these organisms’ lipase...     

Role of interleukin-17 in a murine community-associated methicillin-resistant Staphylococcus aureus pneumonia model

Interleukin (IL)-17 is a key member of the Th17 cytokines and has been reported to be involved in the pathomechanisms underlying various diseases, including infectious diseases. Infections with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have garnered worldwide attention, and the representative USA300 strain is known to cause pneumonia in healthy people, which can be lethal. However, little is known about the role of IL-17 in CA-MRSA pneumonia. In this study, we investigated the role of IL-17 in a CA-MRSA pneumonia animal model. Mortality was higher and occurred at an earlier stage of infection in the IL-17A-knockout mice than in the wild-type (P < 0.01) and IL-17A/F-knockout mice (P < 0.05); however, no significant difference in the intrapulmonary bacterial counts was observed among the three groups of mice. Moreover, the IL-17A-knockout group showed significantly higher levels of IL-17F and granulocyte-colony stimulating factor (G-CSF) and a significantly higher neutrophil count in the bronchoalveolar lavage fluid than the other groups. These results confirmed that G-CSF expression significantly increased, and significant neutrophilic inflammation occurred under conditions of IL-17A deficiency in the murine CA-MRSA pneumonia model.     

Transcriptomic Analysis of Temperature Responses of Aspergillus kawachii during Barley Koji Production

The koji mold Aspergillus kawachii is used for making the Japanese distilled spirit shochu. During shochu production, A. kawachii is grown in solid-state culture (koji) on steamed grains, such as rice or barley, to convert the grain starch to glucose and produce citric acid. During this process, the cultivation temperature of A. kawachii is gradually increased to 40°C and is then lowered to 30°C. This temperature modulation is important for stimulating amylase activity and the accumulation of citric acid. However, the effects of temperature on A. kawachii at the gene expression level have not been elucidated. In this study, we investigated the effect of solid-state cultivation temperature on gene expression for A. kawachii grown on barley. The results of DNA microarray and gene ontology analyses showed that the expression of genes involved in the glycerol, trehalose, and pentose phosphate metabolic pathways, which function downstream of glycolysis, was downregulated by shifting the cultivation temperature from 40 to 30°C. In addition, significantly reduced expression of genes related to heat shock responses and increased expression of genes related with amino acid transport were also observed. These results suggest that solid-state cultivation at 40°C is stressful for A. kawachii and that heat adaptation leads to reduced citric acid accumulation through activation of pathways branching from glycolysis. The gene expression profile of A. kawachii elucidated in this study is expected to contribute to the understanding of gene regulation during koji production and optimization of the industrially desirable characteristics of A. kawachii.     

Unmanned Aerial Survey of Fallen Trees in a Deciduous Broadleaved Forest in Eastern Japan

Since fallen trees are a key factor in biodiversity and biogeochemical cycling, information about their spatial distribution is of use in determining species distribution and nutrient and carbon cycling in forest ecosystems. Ground-based surveys are both time consuming and labour intensive. Remote-sensing technology can reduce these costs. Here, we used high-spatial-resolution aerial photographs (0.5–1.0 cm per pixel) taken from an unmanned aerial vehicle (UAV) to survey fallen trees in a deciduous broadleaved forest in eastern Japan. In nine sub-plots we found a total of 44 fallen trees by ground survey. From the aerial photographs, we identified 80% to 90% of fallen trees that were >30 cm in diameter or >10 m in length, but missed many that were narrower or shorter. This failure may be due to the similarity of fallen trees to trunks and branches of standing trees or masking by standing trees. Views of the same point from different angles may improve the detection rate because they would provide more opportunity to detect fallen trees hidden by standing trees. Our results suggest that UAV surveys will make it possible to monitor the spatial and temporal variations in forest structure and function at lower cost.     

Enantioselective formation of (R)-9-HPODE and (R)-9-HPOTrE in marine green alga Ulva conglobata

When linoleic and linolenic acid were incubated with a crude enzyme of marine green alga Ulva conglobata, the corresponding (R)-9-hydroperoxy-(10E, 12Z)-10, 12-octadecadienoic acid [(R)-9-HPODE] and (R)-9-hydroperoxy-(10E, 12Z, 15Z)-10, 12, 15-octadecatrienoic acid [(R)-9-HPOTrE] were formed with a high enantiomeric excess (>99%), respectively.     

9,10-Phenanthrenequinone promotes secretion of pulmonary aldo-keto reductases with surfactant

9,10-Phenanthrenequinone (9,10-PQ), a major quinone in diesel exhaust particles, induces apoptosis via the generation of reactive oxygen species (ROS) because of 9,10-PQ redox cycling. We have found that intratracheal infusion of 9,10-PQ facilitates the secretion of surfactant into rat alveolus. In the cultured rat lung, treatment with 9,10-PQ results in an increase in a lower-density surfactant by ROS generation through redox cycling of the quinone. The surfactant contains aldo-keto reductase (AKR) 1C15, which reduces 9,10-PQ and the enzyme level in the surfactant increases on treatment with 9,10-PQ suggesting an involvement of AKR1C15 in the redox cycling of the quinone. In six human cell types (A549, MKN45, Caco2, Hela, Molt4 and U937) only type II epithelial A549 cells secrete three human AKR1C subfamily members (AKR1C1, AKR1C2 and AKR1C3) with the surfactant into the medium; this secretion is highly increased by 9,10-PQ treatment. Using in vitro enzyme inhibition analysis, we have identified AKR1C3 as the most abundantly secreted AKR1C member. The AKR1C enzymes in the medium efficiently reduce 9,10-PQ and initiate its redox cycling accompanied by ROS production. The exposure of A549 cells to 9,10-PQ provokes viability loss, which is significantly protected by the addition of the AKR1C3 inhibitor and antioxidant enzyme and by the removal of the surfactants from the culture medium. Thus, the AKR1C enzymes secreted in pulmonary surfactants probably participate in the toxic mechanism triggered by 9,10-PQ.     

CARBON SOURCE DEPENDENCE OF THE RATIO OF δ‐AMINOLEVULINIC ACID BIOSYNTHESIS VIA THE C5 AND SHEMIN PATHWAYS IN EUGLENA GRACILIS (EUGLENOPHYCEAE)1

The ratio of two biosynthetic pathways was estimated, the C5 and Shemin pathways, to δ‐aminolevulinic acid (ALA, a biosynthetic intermediate of tetrapyrrole) from the ¹³C‐enrichment ratios (¹³C‐ER) at the carbon atoms of chl a (after conversion to methyl pheophorbide a) biosynthesized by Euglena gracilis G. A. Klebs when l ‐[3‐¹³C]alanine was used as a carbon source. On the basis of these estimations, we confirmed that ALA was efficiently biosynthesized via both the C5 and Shemin pathways in the plastids of E. gracilis, and we determined that the ratio of ALA biosynthesis via the Shemin pathway was increased in the ratio of 14%–67%, compared with that in our previous d ‐[1‐¹³C]glucose feeding experiment ( Iida et al. 2002 ). This carbon source dependence of the contributions of the two biosynthetic pathways might be related to activation of gluconeogenesis by the amino acid substrate. The methoxy carbon of the methoxycarbonyl group at C‐13² of chl a was labeled with the ¹³C‐carbon of l ‐[methyl‐¹³C]methionine derived from l ‐[3‐¹³C]alanine via [2‐¹³C]acetyl coenzyme A (CoA), through the atypical tricarboxylic acid (TCA) cycle, gluconeogenesis, and l‐ [3‐¹³C]serine. The phytyl moiety of chl a was also labeled on C‐P2, C‐P3¹, C‐P4, C‐P6, C‐P7¹, C‐P8, C‐P10, C‐P11¹, C‐P12, C‐P14, C‐P15¹, and C‐P16 from ¹³C‐isoprene (2‐[1,2‐methyl,3‐¹³C₃]methyl‐1,3‐butadiene) generated from l ‐[3‐¹³C]alanine via [2‐¹³C]acetyl CoA.     

Differential regulatory function of resting and preactivated allergen-specific CD4+ CD25+ regulatory T cells in Th2-type airway inflammation

Although CD4(+)CD25(+) regulatory T (Treg) cells are known to suppress Th1 cell-mediated immune responses, their effect on Th2-type immune responses remains unclear. In this study we examined the role of Treg cells in Th2-type airway inflammation in mice. Depletion and reconstitution experiments demonstrated that the Treg cells of naive mice effectively suppressed the initiation and development of Th2-driven airway inflammation. Despite effective suppression of Th2-type airway inflammation in naive mice, adoptively transferred, allergen-specific Treg cells were unable to suppress airway inflammation in allergen-presensitized mice. Preactivated allergen-specific Treg cells, however, could suppress airway inflammation even in allergen-presensitized mice by accumulating in the lung, where they reduced the accumulation and proliferation of Th2 cells. Upon activation, allergen-specific Treg cells up-regulated CCR4, exhibited enhanced chemotactic responses to CCR4 ligands, and suppressed the proliferation of and cytokine production by polarized Th2 cells. Collectively, these results demonstrated that Treg cells are capable of suppressing Th2-driven airway inflammation even in allergen-presensitized mice in a manner dependent on their efficient migration into the inflammatory site and their regulation of Th2 cell activation and proliferation.     

A synthetic peptide corresponding to residues 301-320 of human Wnt-1 promotes PC12 cell adhesion and hippocampal neural stem cell differentiation

Wnt signaling cascades play a crucial role in the maintenance of stem cell niches in many tissues as well as in embryonic patterning and cell-fate determination. Wnt signaling pathways have been well studied; however, the precise binding mechanism of Wnt protein to its receptor has not yet been clarified. Here we show the design and synthesis of seven novel peptide candidates for a receptor-binding site of human Wnt-1 based on its hydrophilicity and beta-turn profiles. Among these Wnt-derived peptides, only WP7, which corresponds to residues 301-320 of human Wnt-1, bound to the soluble receptor for Wnt-1, mouse Frizzled-1/Fc chimera, promoted PC12 cell adherence, increased level of cytosolic beta-catenin in PC12 cells, and induced adhesion and neuronal differentiation of hippocampal neural precursor cells. These results suggest that residues 301-320 of human Wnt-1 is one of the receptor-binding sites and that WP7 may activate the canonical Wnt pathway. When combined with an appropriate matrix, the action of this Wnt-derived peptide, WP7, can be limited to within a location, and therefore could be useful in the regeneration of many tissues, without fear of tumor generation.