Isolation and Identification of a Microorganism Producing Bilirubin Oxidase

For the purposes of decoloring raw sewage and use as an analytical tool in clinical fields, we tried to obtain microorganisms producing an enzyme which is reactive to bilirubin. One strain of microorganism (MT-1) showed strong ability to produce the enzyme.

The morphological and physiological characteristics of strain MT-1 were studied. This strain was found to belong to Myrothecium verrucaria.

For the production of the enzyme, this strain was aerobically cultured at 25°C in a jar fermentor which contained potato-glucose medium. The highest activity was obtained after 62-hr cultivation.

This enzyme was also produced by other strains belonging to Myrothecium.     

Multiple Group I Introns in the Small-Subunit rDNA of Botryosphaeria dothidea: Implication for Intraspecific Genetic Diversity

Botryosphaeria dothidea is a widespread and economically important pathogen on various fruit trees, and it often causes die-back and canker on limbs and fruit rot. In characterizing intraspecies genetic variation within this fungus, group I introns, rich in rDNA of fungi, may provide a productive region for exploration. In this research, we analysed complete small subunit (SSU) ribosomal DNA (rDNA) sequences of 37 B. dothidea strains, and found four insertions, designated Bdo.S943, Bdo.S1199-A, Bdo.S1199-B and Bdo.S1506, at three positions. Sequence analysis and structure prediction revealed that both Bdo.S943 and Bdo.S1506 belonged to subgroup IC1 of group I introns, whereas Bdo.S1199-A and Bdo.S1199-B corresponded to group IE introns. Moreover, Bdo.S1199-A was found to host an open reading frame (ORF) for encoding the homing endonuclease (HE), whereas Bdo.S1199-B, an evolutionary descendant of Bdo.S1199-A, included a degenerate HE. The above four introns were novel, and were the first group I introns observed and characterized in this species. Differential distribution of these introns revealed that all strains could be separated into four genotypes. Genotype III (no intron) and genotype IV (Bdo.S1199-B) were each found in only one strain, whereas genotype I (Bdo.S1199-A) and genotype II (Bdo.S943 and Bdo.S1506) occurred in 95% of the strains. There is a correlation between B. dothidea genotypes and hosts or geographic locations. Thus, these newly discovered group I introns can help to advance understanding of genetic differentiation within B. dothidea.     

The Fission Yeast Minichromosome Maintenance (MCM)-binding Protein (MCM-BP), Mcb1, Regulates MCM Function during Prereplicative Complex Formation in DNA Replication

The minichromosome maintenance (MCM) complex is a replicative helicase, which is essential for chromosome DNA replication. In recent years, the identification of a novel MCM-binding protein (MCM-BP) in most eukaryotes has led to numerous studies investigating its function and its relationship to the MCM complex. However, the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood; in addition, the functional role of MCM-BP remains controversial and may vary between model organisms. The present study aims to elucidate the nature and biological function of the MCM-BP ortholog, Mcb1, in fission yeast. The Mcb1 protein continuously interacts with MCM proteins during the cell cycle in vivo and can interact with any individual MCM subunit in vitro. To understand the detailed characteristics of mcb1⁺, two temperature-sensitive mcb1 gene mutants (mcb1^ts) were isolated. Extensive genetic analysis showed that the mcb1^ts mutants were suppressed by a mcm5⁺ multicopy plasmid and displayed synthetic defects with many S-phase-related gene mutants. Moreover, cyclin-dependent kinase modulation by Cig2 repression or Rum1 overproduction suppressed the mcb1^ts mutants, suggesting the involvement of Mcb1 in pre-RC formation during DNA replication. These data are consistent with the observation that Mcm7 loading onto replication origins is reduced and S-phase progression is delayed in mcb1^ts mutants. Furthermore, the mcb1^ts mutation led to the redistribution of MCM subunits to the cytoplasm, and this redistribution was dependent on an active nuclear export system. These results strongly suggest that Mcb1 promotes efficient pre-RC formation during DNA replication by regulating the MCM complex.     

Effect of Validamycin on Production of Some Enzymes in Rhizoctonia solani

A remarkable effect of validamycin on the morphology of Rhizoctonia solani was seen after 2 days culture when the fungus was cultivated in a Roux flask with standing. In accordance with the morphological change, the production of laminarinase and glucan synthetase by the fungus was affected by validamycin.

The production of laminarinase was increased in the culture filtrate, and significantly decreased in the mycelium in the presence of validamycin. While the intracellular production of glucan synthetase in the culture with validamycin (10~50μg/ml) increased by 40~60% compared with that in the control culture.     

A Novel Acylaminoimidazole Derivative,WN1316, Alleviates Disease Progression via Suppression of Glial Inflammation in ALS Mouse Model

Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron degenerative disease. Given that oxidative stress and resulting chronic neuronal inflammation are thought to be central pathogenic, anti-oxidative agents and modulators of neuronal inflammation could be potential therapies for ALS. We report here that the novel small molecular compound, 2-[mesityl(methyl)amino]-N-[4-(pyridin-2-yl)-1H-imidazol-2-yl] acetamide trihydrochloride (WN1316) selectively suppresses oxidative stress-induced cell death and neuronal inflammation in the late-stage ALS mice. WN1316 has high blood-brain-barrier permeability and water solubility, and boosts both neuronal apoptosis inhibitory protein (NAIP) and NF-E2-related factor 2 (Nrf2) which governed glutathione (GSH)-related anti-oxidation pathway protecting motor neurons against oxidative injuries. Post-onset oral administration of low dose (1–100 µg/kg/day) WN1316 in ALS(SOD1^H46R) and ALS(SOD1^G93A) mice resulted in sustained improved motor function and post onset survival rate. Immunohistochemical analysis revealed less DNA oxidative damage and motor neuronal inflammation as well as repression of both microgliosis and astrocytosis, concomitant down regulation of interleukin-1β and inducible nitric oxide synthase, and preservation of the motoneurons in anterior horn of lumbar spinal cord and skeletal muscle (quadriceps femoris). Thus, WN1316 would be a novel therapeutic agent for ALS.     

High-resolution crystal structures of transient intermediates in the phytochrome photocycle

1. Download : Download high-res image (234KB)
2. Download : Download full-size image

     

Reaction of 5-Carboxypyrimidine Derivatives with Sodium Bisulfite

5-Carboxyuracil derivatives were shown to react with aqueous sodium bisulfite in mild condition resulting in facile decarboxylation to give corresponding 5-decarboxy-5,6-dihydrouracil-6-sulfonates and uracils in good yield. The former compounds were quantitatively transformed to the latter in alkaline condition. Mechanistic feature of this reaction was discussed, which implied the initial nucleophilic addition of bisulfite across the 5,6-double bond. 5-Carboxycytosine was also shown to react similarly, however, accompanied by hydrolytic deamination.