Enumeration of the genusPeziza in Japan:Peziza limnaea andPeziza rifaii

Two species in the genusPeziza are described and illustrated as new to Japan:Peziza limnaea andPeziza rifaii. These species were collected in the broad-leaved forest mainly withCastanopsis cuspidata in Chiba Pref.     

Fruiting-body formation, cultivation properties, and host specificity of a fungicolous fungus, Asterophora lycoperdoides

We report the fruiting-body formation and cultivation properties of Asterophora lycoperdoides, a fungicolous fungus. Asterophora lycoperdoides formed fruiting bodies on potato dextrose agar medium in approximately 1 week, although this fungus shows high host specificity to Russula nigricans in nature. Optimal temperature of mycelial growth and fruiting-body formation was 25°C. Mannitol or soluble starch was preferably used as a carbon source, and amino nitrogen was preferably used as the nitrogen source. For a better understanding of the relationship between A. lycoperdoides and R. nigricans, we cultivated A. lycoperdoides on media supplemented with freeze-dried fruiting bodies of various fungi. The germination rate was approximately 2.5 times higher on the medium containing freeze-dried R. nigricans than that on the PDA medium. The mycelia extended most rapidly in the presence of R. nigricans. Furthermore, the stipe length of its fruiting body was the longest on the medium containing R. nigricans. These results indicated that A. lycoperdoides can grow faster by utilizing certain substances that are abundantly contained in R. nigricans, such as mannitol, or by utilizing R. nigricans itself. It is considered that the constituents of R. nigricans might contribute to the host specificity of A. lycoperdoides.     

Role of matricellular proteins in cardiac tissue remodeling after myocardial infarction

After onset of myocardial infarction (MI), the left ventricle (LV) undergoes a continuum of molecular, cellular, and extracellular responses that result in LV wall thinning, dilatation, and dysfunction. These dynamic changes in LV shape, size, and function are termed cardiac remodeling. If the cardiac healing after MI does not proceed properly, it could lead to cardiac rupture or maladaptive cardiac remodeling, such as further LV dilatation and dysfunction, and ultimately death. Although the precise molecular mechanisms in this cardiac healing process have not been fully elucidated, this process is strictly coordinated by the interaction of cells with their surrounding extracellular matrix (ECM) proteins. The components of ECM include basic structural proteins such as collagen, elastin and specialized proteins such as fibronectin, proteoglycans and matricellular proteins. Matricellular proteins are a class of non-structural and secreted proteins that probably exert regulatory functions through direct binding to cell surface receptors, other matrix proteins, and soluble extracellular factors such as growth factors and cytokines. This small group of proteins, which includes osteopontin, thrombospondin-1/2, tenascin, periostin, and secreted protein, acidic and rich in cysteine, shows a low level of expression in normal adult tissue, but is markedly upregulated during wound healing and tissue remodeling, including MI. In this review, we focus on the regulatory functions of matricellular proteins during cardiac tissue healing and remodeling after MI.     

Specific epidermal growth factor receptor autophosphorylation sites promote mouse colon epithelial cell chemotaxis and restitution

Upon ligand binding, epidermal growth factor (EGF) receptor (R) autophosphorylates on COOH-terminal tyrosines, generating docking sites for signaling partners that stimulate proliferation, restitution, and chemotaxis. Specificity for individual EGFR tyrosines in cellular responses has been hypothesized but not well documented. Here we tested the requirement for particular tyrosines, and associated downstream pathways, in mouse colon epithelial cell chemotactic migration. We compared these requirements to those for the phenotypically distinct restitution (wound healing) migration. Wild-type, Y992/1173F, Y1045F, Y1068F, and Y1086F EGFR constructs were expressed in EGFR(-/-) cells; EGF-induced chemotaxis or restitution were determined by Boyden chamber or modified scratch wound assay, respectively. Pharmacological inhibitors of p38, phospholipase C (PLC), Src, MEK, JNK/SAPK, phosphatidylinositol 3-kinase (PI 3-kinase), and protein kinase C (PKC) were used to block EGF-stimulated signaling. Pathway activation was determined by immunoblot analysis. Unlike wild-type EGFR, Y992/1173F and Y1086F EGFR did not stimulate colon epithelial cell chemotaxis toward EGF; Y1045F and Y1068F EGFR partially stimulated chemotaxis. Only wild-type EGFR promoted colonocyte restitution. Inhibition of p38, PLC, and Src, or Grb2 knockdown, blocked chemotaxis; JNK, PI 3-kinase, and PKC inhibitors or c-Cbl knockdown blocked restitution but not chemotaxis. All four EGFR mutants stimulated downstream signaling in response to EGF, but Y992/1173F EGFR was partially defective in PLCγ activation whereas both Y1068F and Y1086F EGFR failed to activate Src. We conclude that specific EGFR tyrosines play key roles in determining cellular responses to ligand. Chemotaxis and restitution, which have different migration phenotypes and physiological consequences, have overlapping but not identical EGFR signaling requirements.     

Biomarker discovery for kidney diseases by mass spectrometry

By the development of soft ionization such as matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), mass spectrometry (MS) has become an indispensable technique to analyze proteins. The combination of protein separation and identification such as two-dimensional gel electrophoresis and MS, surface-enhanced laser desorption/ionization-MS, liquid chromatography/MS, and capillary electrophoresis/MS has been successfully applied for proteome analysis of urine and plasma to discover biomarkers of kidney diseases. Some urinary proteins and their proteolytic fragments have been identified as biomarker candidates for kidney diseases. This article reviews recent advances in the application of proteomics using MS to discover biomarkers for kidney diseases.     

Characterization of the nematocidal toxocyst in <Emphasis Type="Italic">Pleurotus</Emphasis> subgen. <Emphasis Type="Italic">Coremiopleurotus</Emphasis>

Toxocysts of the genus Pleurotus are blastoconidia-like ovoid structures surrounded by a liquid droplet containing a toxin that paralyzes nematodes. This study investigated toxocyst development using a strain S396 of Pleurotus cystidiosus subsp. abalonus (subgen. Coremiopleurotus). The surface of the liquid droplet was found to be an elastic envelope. When a nematode touches the toxocyst, the envelope adheres to the worm and bursts. Toxocysts are induced simultaneously with coremia formation in the absence of nematodes and developed only from aerial hyphae in which nuclear division had ceased. In the early stage of toxocyst development, liquid springs repeatedly from the tip of the sterigma-like stipe before ovoid (blastoconidium-like structure) formation. A certain substance in the liquid might polymerize to form the envelope while the ovoid simultaneously budded in the droplet. The nucleus tends to locate near the toxocyst, especially in early stage of toxocyst development. Each dikaryotic cell predominantly formed one or two toxocyst(s) while each monokaryotic cell predominantly formed one. In rare cases, a nucleus existed in the toxocyst, suggesting the possibility that the toxocyst is a vestigial blastoconidium.     

Carbenoxolone inhibits Pannexin1 channels through interactions in the first extracellular loop

Pannexin1 (Panx1) is an ATP release channel important for controlling immune responses and synaptic strength. Various stimuli including C-terminal cleavage, a high concentration of extracellular potassium, and voltage have been demonstrated to activate Panx1. However, it remains unclear how Panx1 senses and integrates such diverse stimuli to form an open channel. To provide a clue on the mechanism underlying Panx1 channel gating, we investigated the action mechanism of carbenoxolone (CBX), the most commonly used small molecule for attenuating Panx1 function triggered by a wide range of stimuli. Using a chimeric approach, we discovered that CBX reverses its action polarity and potentiates the voltage-gated channel activity of Panx1 when W74 in the first extracellular loop is mutated to a nonaromatic residue. A systematic mutagenesis study revealed that conserved residues in this loop also play important roles in CBX function, potentially by mediating CBX binding. We extended our experiments to other Panx1 inhibitors such as probenecid and ATP, which also potentiate the voltage-gated channel activity of a Panx1 mutant at position 74. Notably, probenecid alone can activate this mutant at a resting membrane potential. These data suggest that CBX and other inhibitors, including probenecid, attenuate Panx1 channel activity through modulation of the first extracellular loop. Our experiments are the first step toward identifying a previously unknown mode of CBX action, which provide insight into the role of the first extracellular loop in Panx1 channel gating.     

Tailor-making of protein drugs by polymer conjugation for tumor targeting: A brief review on smancs

Chemical conjugation of poly(styrene-co-maleic acid) to an antitumor protein (neocarzinostatin) yielded an entirely new derivative designated as smancs (polystyrene-maleic acid conjugated neocarzinostatin). The purpose of the modification was to improve its pharmacological properties; the resulting conjugate exhibited much higher tumoritropism and lymphotropism, enhancedin vivo stability (about ten times), higher chemotherapeutic index (lower toxicity), and decreased antigenicity. Another advantage associated with this molecular engineering was an increased hydrophobicity. By this character it was solubilized in lipid contrast medium Lipiodol^R, which facilitated highly sensitive detection under x-ray-accompanying selective anticancer effectin situ. Three factors were responsible for such improvements: molecular size, hydrophobicity, and polyanionic nature. Most of the known drugs so far used as therapeutic agents are less than 1000 daltons, and those with larger molecular weights have been explored much less extensively. By polymer conjugation, the size of the drug can be extended to about 15,000 daltons (macromolecular therapeutics). The most outstanding characteristic of smancs (16,000 daltons) was the tumoritropicity, which may be a result of the highly developed neovasculature of solid tumors. Smancs as a prototype drug thus appears to lead the way in cancer drug targeting.