The ComX pheromone is a post-translationally modified oligopeptide that stimulates natural genetic competence controlled by quorum sensing in Bacillus subtilis. The structure of the ComXRO-E-2 pheromone produced by strain RO-E-2 was determined. In the pheromone molecule, a geranyl group is bound to the tryptophan residue, which results in the formation of a tricyclic ring structure. Molds in the genus Phytophthora are some of the most destructive phytopathogens known. An important biological event in Phytophthora is sexual reproduction. A factor known as hormone α1 is secreted by the A1 mating type, and this induces the formation of oospores in the A2 mating type. The structure of hormone α1 is a C-20 linear isoprenoid and the absolute stereochemistry was determined by chemical synthesis.
To elucidate the molecular mechanism underlying the toxicity of the Fusarium mycotoxin nivalenol, we investigated the involvement of stress-activated MAP kinases (SAPKs; c-Jun Nterminal kinases (JNKs) and p38s) in nivalenol-caused cytotoxicity and interleukin (IL) -8 secretion in human promyelocytic leukemia HL60 cells. Nivalenol treatment for 24 h increased the phosphorylated (i.e., the active-form) JNKs with maximum effect at 1 μg/mL; when nivalenol was given at this concentration in a time-series experiment, phosphorylated JNK quantity peaked at 12 h and then decreased. Essentially the same results were obtained for phosphorylated (active-form) p38s. To elucidate the functions of SAPKs, we investigated the effects of the JNK-specific inhibitor SP600125 and the p38-specific inhibitor SB203580 on nivalenol-caused cytotoxicity and IL-8 secretion. Nivalenol hindered cell proliferation regardless of the presence or absence of SAPK-specific inhibitors. However, co-treatment with SAPK inhibitors reduced this effect, indicating that JNKs and p38s play roles in nivalenolassociated retardation of cell proliferation. SP600125 significantly reduced nivalenol-induced IL-8 secretion, indicating that JNKs contribute to this phenomenon. SB203580 moderately lessened nivalenol-elicited IL-8 secretion, however, the contribution of p38s to nivalenolinduced IL-8 secretion appears to be meaningful, because SB203580 alone markedly increased IL-8 secretion.
Dihydroterrein (1) and terrein (2) were isolated from methanol extracts of the solid culture of Asperillus novofumigatus IFM 55215. Both 1 and 2 inhibited human platelet aggregation induced by collagen at a concentration of 5.0 × 102 μmol/L in vitro and they displayed slight inhibitory effects when platelet aggregation was induced by adenosine diphosphate (ADP). Inhibitory activity of dihydroterrein diacetate (3) and terrein diacetate (4) on platelet aggregation was also examined. Compound 4 was found to possess the highest inhibitory effect on both collagen- and ADP-induced platelet aggregation among 1 - 4.
Cross-linked poly-γ-glutamic acid (C-L γ-PGA) markedly purified polluted water collected from rivers and ponds by flocculation and precipitation. This effect of C-L γ-PGA occasionally required pretreatment with polyaluminum chloride (PAC). Components of polluted water in rivers or ponds are generally thought to be clay minerals, microorganisms and chemical compounds. In this study, the flocculating activities of C-L γ-PGA against suspensions of bentonite, diatomaceous earth, Escherichia coli and Mycrocystis aeruginosa, and against solutions of crystal violet and bisphenol A were investigated. The mode of action of C-L γ-PGA is thought to be based on electrostatic interaction between flocculants, C-L γ-PGA and PAC, and the surface of polluted water components, which may lead to neutralization of the zetapotential of those components.
Data analysis procedures using an example are shown on collaborative studies for quantitative chemical methods. Key points of international guidelines of collaborative studies are explained through the example. Trend of the collaborative studies for quantitative analysis of mycotoxin was analyzed as reference for design of collaborative studies.
For a guideline of validating a method of analysis, Official Methods of Analysis (OMA) of AOAC International is nominated for a representative example. On the other hand, in European Community, it came to establish a standard about a performance of analytical methods for the monitoring of certain substances and residues thereof in live animals and animal products, because the residues of forbidden veterinary drugs in foods such as shrimps or honeys was confirmed from China. It is Commission Decision 2002/657/EC. Because the validation method mentioned here intends for the toxic substance in live animals and animal products, the grains that contamination of the mycotoxins concerned about are not objects. However, there are characteristic mentions in this document about the mass spectrometer which spread in late years,therefore, I comment on them mainly.
Internal quality control (IQC) is continuous activities in analytical laboratories in order to ensure reliability of analytical results. The major techniques for IQC are blank tests, recovery checks, statistical IQC with control materials and duplicate tests. Spike tests, Confirmation tests and so on can be also used for IQC. Depending on the characteristics and the circumstances of testing, IQC is constructed by the combination of these techniques in practice.
The sample quantity when the aflatoxin of grainy farm products is inspected has been basically decided 1 kg in our country. However, the precision of analysis is not good to quantify the concentration of pollutant of the entire lot because of the sampling error which causes from extremely different aflatoxin contamination in each grain. In an international trade, the improvement of sampling is being demanded by various foreign countries. It was researched to improve grainy farm products, that is, the amount of sampling such as corn, peanuts, and the tree nuts referring to the research of the sampling methodology of Whitaker and Johansson. And, the sample quantity of these grainy farm products proposed to have to assume 10,000 grains or kernels,e.g. 3.2 kg of corn, or more.