Characterization of translucent segments observed in an smbA mutant of Escherichia coli

Abstract The smbA gene of Escherichia coli is essential for cell proliferation. The smbA2 mutant shows cold-sensitive colony formation at 22°C. A novel morphological phenotype, formation of a translucent segment at midcell or at a cell pole, was observed by phase-contrastt microscopy at a high frequency in the smbA2 mutant cells incubated in L medium lacking NaCl at 22°C, but not observed in L medium containing 1% NaCl or 20% sucrose at the same temperature. No translucent segment was observed in the wild-type cells in any of the media used. Electron microscopic observation revealed that the translucent segments resulted from the enlargement of a periplasmic space by separation of the inner membrane from the peptidoglycan layer and the outer membrane.     

The Alarm Pheromone of the Mite Suidasia medanensis OUDEMANS, 1924 (Acariformes,Suidasiidae)

The stored-product mite Suidasia medanensis has been found in human-provided habitats in Japan. The mite uses neral as the alarm pheromone, and also secretes (Z,E)- and (£,£)-farnesal, which were isolated from an astigmatid mite for the first time. On the other hand, S. medanensis is the only mite out of fifteen species investigated so far that does not secrete volatile hydrocarbons along with the alarm pheromone, though 9-nonadecene and 6,9-nonadecadiene were found in a hexane extract of the mite. GC-MS, ^JH-NMR and ¹³C-NMR of the four isomers of synthetic farnesal, which were isolated by LC and preparative GLC, cleared up some confusion in the literature concerning the stereochemistry of this sesquiterpenoid.     

Fractionation of Main Components and Their Subunits of Soybean Proteins

The water-extracted proteins, C and D fractions prepared from defatted soybean meals were fractionated by a method of gel filtration with Sephadex G–200, resulting in higher purification of the C and D components. The dissociated subunits of the C and D components were seen as bands B and B′ on the starch-gel electrophoretical pattern of system without urea. By the starch-gel electrophoresis in system with urea, the subunits of C component were mainly corresponding to the bands 7, 8 and 9, and those of the D component mainly to the band 10. Those subunits were fractionated by column chromatography on DEAE-cellulose contained urea.     

Phospholipid-Derived Fatty Acids and Quinones as Markers for Bacterial Biomass and Community Structure in Marine Sediments

Phospholipid-derived fatty acids (PLFA) and respiratory quinones (RQ) are microbial compounds that have been utilized as biomarkers to quantify bacterial biomass and to characterize microbial community structure in sediments, waters, and soils. While PLFAs have been widely used as quantitative bacterial biomarkers in marine sediments, applications of quinone analysis in marine sediments are very limited. In this study, we investigated the relation between both groups of bacterial biomarkers in a broad range of marine sediments from the intertidal zone to the deep sea. We found a good log-log correlation between concentrations of bacterial PLFA and RQ over several orders of magnitude. This relationship is probably due to metabolic variation in quinone concentrations in bacterial cells in different environments, whereas PLFA concentrations are relatively stable under different conditions. We also found a good agreement in the community structure classifications based on the bacterial PLFAs and RQs. These results strengthen the application of both compounds as quantitative bacterial biomarkers. Moreover, the bacterial PLFA- and RQ profiles revealed a comparable dissimilarity pattern of the sampled sediments, but with a higher level of dissimilarity for the RQs. This means that the quinone method has a higher resolution for resolving differences in bacterial community composition. Combining PLFA and quinone analysis as a complementary method is a good strategy to yield higher resolving power in bacterial community structure.     

Laboratory and field assessment of molluscicidal activity of B-2 against Oncomelania hupensis, the vector snail of schistosomiasis in China

Molluscicidal activity of B-2 (sodium 2,5-dichloro-4-bromophenol; called as Phebrol and registered in WHO as OMS 3012) was evaluated in a laboratory and the field trials were performed in two different localities in Yueyang city, China, for control of Oncomelania hupensis. B-2 was effective against O. hupensis both in the laboratory and in the field. A dosage of 50 g/m2 in 10% granular form or 20 ml/m2 in 25% liquid form of B-2 would be recommendable as a standard mollusciciding dose for control of O. hupensis.