Antimutagenicity of some edible Thai plants,and a bioactive carbazole alkaloid,mahanine, isolated from Micromelum minutum

The antimutagenic activity against Trp-P-1 of methanolic extracts of 118 samples (108 species) of edible Thai plants was examined by the Ames Test. The activity was evaluated by the amount of plant extracts which suppressed 90% of the mutagenesis (ED90). Five plants, Micromelum minutum, Oroxylum indicum, Cuscuta chinensis, Azadirachta indica, and Litsea petiolata, exhibited significant activity with antimutagenic ED90 values lower than 5 microL/plate (0.1 mg of dry plant material equivalent). The activity-guided fractionation of the extract of M. minutum, which exhibited the highest antimutagenic activity in the screening, resulted in the isolation of an active principle, (+)-mahanine (1) as confirmed by its physicochemical properties. Compound 1 showed a wide variety of biological activity, including antimutagenicity against heterocyclic amines such as Trp-P-1 with an IC50 of 5.2 microM, cytotoxicity against a tumor cell line HL60 with a MIC100 of 4.0 microg/mL, and antimicrobial activity against Bacillus cereus and Staphylococcus aureus with MIC100 values of 6.25 and 12.5 microg/mL, respectively.     

Simulation method to generate the strength of glulam using correlated random variables

Many reports have been published about designing the strength of glulam using simulation methods. In simulation methods, one of the most important problems is how to deal with correlations among strength factors, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), tensile strength (σ_T), and compression strength (σ_C). For example, in the case that the MOR criteria of glulam is σ _ni /f _ni + σ _bi /f _bi ≥ 1 (where σ _ni and σ _bi are the axial stress and the bending stress of the i-th lamina respectively, and f _ni and f _bi are the axial strength and the bending strength of the i-th lamina respectively), a correlation between f _ni and f _bi exists. How can we account for this correlation when calculating the strength of glulam, bearing in mind that it is very difficult to measure the correlation coefficients among MOR, σ_T, and σ_C? We developed a method by which these problems could be solved, and, using random variables generated by this method, the strengths of glulam were simulated. The simulated values were almost the same as the experimental values. The results indicated the usefulness of the method.     

Bora and the kinase Aurora a cooperatively activate the kinase Plk1 and control mitotic entry

A central question in the study of cell proliferation is, what controls cell-cycle transitions? Although the accumulation of mitotic cyclins drives the transition from the G2 phase to the M phase in embryonic cells, the trigger for mitotic entry in somatic cells remains unknown. We report that the synergistic action of Bora and the kinase Aurora A (Aur-A) controls the G2-M transition. Bora accumulates in the G2 phase and promotes Aur-A-mediated activation of Polo-like kinase 1 (Plk1), leading to the activation of cyclin-dependent kinase 1 and mitotic entry. Mechanistically, Bora interacts with Plk1 and controls the accessibility of its activation loop for phosphorylation and activation by Aur-A. Thus, Bora and Aur-A control mitotic entry, which provides a mechanism for one of the most important yet ill-defined events in the cell cycle.     

Biocontrol of Pythium root rot on lisianthus using a new dark septate endophytic fungus Hyaloscypha variabilis J1PC1

European Journal of Plant Pathology - Pythium root rot is one of the most destructive diseases on lisianthus in Japan. Current management strategies against Pythium root rot are insufficient in...     

Diurnal Characteristics of Suspended Particulate Matter and PM<Subscript>2.5</Subscript> in the Urban and Suburban Atmosphere of the Kanto Plain,Japan

Suspended particulate matter (SPM) and PM_2.5 in the urban and suburban atmosphere of the Kanto Plain of Japan, which includes the Tokyo metropolitan area, during the period 22–26 July 2002 were characterized. Samples of SPM and PM_2.5 were collected by low-volume samplers at 6-h intervals at Suginami, Saitama, and Kisai. At all the sites, the major components of SPM and PM_2.5 were organic carbon (OC), elemental carbon (EC), and sulfate. The ion balance, the size distributions of the ionic species, and the high correlation between SO₄ ^2? and NH₄ ⁺ indicated that the main chemical form of sulfate was (NH₄)₂SO₄. The OC/EC ratios were larger in the daytime than in the nighttime. The correlation coefficients of OC, OC/EC, and SO₄ ^2? with ozone concentrations at inland sites (Saitama, Kisai) were higher than those at the coastal site (Suginami). Bound water and hydrogen and oxygen atoms associated with OC, the amounts of which were estimated with a mass closure model, contributed substantially to the total particle mass. The chemical characteristics of the particles indicated that two mechanisms led to high concentrations of SPM and PM_2.5: (i) an active photochemical process produced high concentrations of OC and sulfate, leading to a high concentration of (NH₄)₂SO₄ in the particles and to production of secondary organic aerosols; (ii) stable meteorological conditions resulted in accumulation of primary particles, mainly emitted from vehicle exhaust, resulting in high concentrations of OC and EC.     

Lignification in developing culms of bamboo <Emphasis Type="Italic">Sinobambusa tootsik</Emphasis>

Bamboos are among the largest woody grasses and grow very rapidly. Although lignin is a crucial factor for the utilization of bamboo biomass, the lignification mechanism of bamboo shoots is poorly understood. We studied lignification in the bamboo Sinobambusa tootsik during culm development. Elongation growth began in May and ended in late-June, when the lignin content was approximately half that in mature culms. Thioacidolysis analysis indicated that p-hydroxyphenyl units in lignin formed even at late stages of lignification. The syringyl/guaiacyl ratio varied during culm development. Various lignin precursors were detected in developing culms by liquid chromatography–mass spectrometry. The ferulic acid content decreased from May to June, indicating that ferulic acid was utilized in early stages of cell wall formation. Monolignol glucosides were detected at early stages of lignification, whereas the contents of monolignols, coniferaldehyde, sinapaldehyde, p-coumaric acid, and ferulic acid peaked at later stages of lignification. Therefore, lignin precursors may be supplied differentially during the lignification process. In August, the rate of lignification decreased, although the contents of various lignin precursors peaked, implying that the rate-limiting step in the cessation of lignification in bamboo is transport or polymerization of lignin precursors, rather than their biosynthesis.     

Influence of Amylose Content on Cookie and Sponge Cake Quality and Solvent Retention Capacities in Wheat Flour

Reduced amylose wheat (Triticum æstivum L.) produces better quality noodles and bread less prone to going stale, while little is known about the relationships between amylose content and the quality of soft wheat baking products such as sugar snap cookies (SSC) and Japanese sponge cakes (JSC). Near‐isogenic lines developed from wheat cultivar Norin 61, differing in their level of granule‐bound starch synthase (Wx protein) activity, were used to produce wheat grains and ultimately flours of different amylose contents. These were tested with regard to their effect on soft wheat baking quality and solvent retention capacities (SRC). Amylose content was strongly correlated to cookie diameter (r = 0.969, P < 0.001) and cake volume (r = 0.976, P < 0.001), indicating that the soft wheat baking quality associated with SSC diameter and JSC volume were improved by an incremental increases in amylose content. Among the four kinds of SRC tests (water, sodium carbonate, sucrose and lactic acid), the water SRC test showed the highest correlation with amylose content, SSC diameter, and JSC volume. When the regression analysis was conducted between the nonwaxy and partial waxy isogenic lines that are available in commercial markets, only water SRC was significantly correlated to amylose content (r = –0.982, P < 0.001) among of four SRC tests. This suggests that, unlike udon noodle quality, high‐amylose content is indispensable in improving soft wheat baking quality, a process requiring less water retention capacity.