Direct transesterification of all classes of lipids in a one-step reaction

Conventional techniques for the determination of fatty acid composition of lipids require solvent extraction, purification, hydrolysis, and derivatization procedures that are both lengthy and cumbersome. A 1-hr direct transesterification procedure carried out in methanol-benzene 4:1 with acetyl chloride circumvented all these steps and was applicable for analysis of both simple (triglycerides) and complex lipids (cholesteryl esters, phospholipids, and sphingomyelin). Recoveries (greater than 95%) of standards unaffected by the presence of 5% water and 200 mg of silica suggested that the technique could be used for the quantitative analysis of total fatty acids as well as of fatty acids in classes of lipids separated on silica from biological samples. When compared to the Folch procedure, the technique led to a 20.1% increase in total fatty acids for plasma, 3.9% for feces, 7.4% for bile, and 9.7% for rat liver. We therefore conclude that this one-step direct transesterification procedure is superior to currently used methods, not only because of its simplicity and speed, but also because of its added precision.     

Identification of Tn4430, a transposon of Bacillus thuringiensis functional in Escherichia coli

Summary The mobile genetic element Tn4430, originating from the gram-positive bacterium, Bacillus thuringiensis, and previously described as the Th-sequence, is the first transposon isolated from the genus Bacillus. In the present work a gene (APH-III) conferring resistance to kanamycin was inserted into this 4.2 kb transposon. Transposition experiments showed that Tn4430APH-III could transpose in the gram-negative host Escherichia coli when its insertion functions were supplied by an intact copy of Tn4430. By transposing Tn4430APH-III directly onto pBR322, it was possible to determine the nucleotide sequence of the terminal inverted repeats of Tn4430 and of the target DNA site. Identical 38 bp in inverted orientation are situated at each end of the transposon and there is a direct duplication of 5 bp at the insertion site. Thus, it is clear that Tn4430 is closely related to the transposons belonging to the Tn3 family (class II elements).     

Vicilin genes ofPisum

Summary We describe four genomic clones of pea 7S storage protein gene, one of which corresponds to convicilin, and the others to vicilin. Hybridization studies exploiting these clones, and previously identified cDNA clones, have enabled us to define six different loci. Three of these loci have been mapped to positions on chromosome 7.     

Multiple transformation of plant cells by Agrobacterium may be responsible for the complex organization of T-DNA in crown gall and hairy root

Summary Inoculation of carrot discs and Lotus corniculatus plantlets with mixtures of different Agrobacterium rhizogenes or of A. rhizogenes and A. tumefaciens or with Agrobacterium strains harboring both an Ri and a modified Ti plasmid resulted in frequent multiple (pluribacterial) transformation of cells, as revealed by the mixed opine-type of hairy roots arising from them. Multiple transformation may account for the presence of dispersed T-DNA inserts in crown gall and hairy root lines. A plant genetic engineering strategy based on segregation of T-DNA inserts in the progeny of multiple transformants is proposed.     

Differences in adhesiveness among type 1 fimbriate strains of Enterobacteriaceae revealed by an in vitro HEp2 cell adhesion model

Ten type 1 fimbriate strains of Enterobacteriaceae were examined in an in vitro adhesion assay with HEp2 epithelial cells. The range of HEp2 cell adhesiveness, which was characteristic for each strain, was affected by motility, type 1 fimbriation and production of mannose sensitive haemagglutinin. Nevertheless, not all type 1 fimbriate strains adhered well in this model. The findings are discussed with regard to the possibility that different type 1 fimbriate enterobacteria, though all are mannose sensitive, recognize different mannose-containing receptors present or available on the surfaces of the HEp2 cells.     

Rhodocybe pulchrisperma (Entolomataceae): A new species from North America

Rhodocybe pulchrisperma is described as a new species of Agaricales from North America. It belongs in section Rhodocybe due to the brightly colored pseudocystidia and lack of clamp connections. The very large, handsomely ornamented basidiospores distinguish this species from others in the section. A key to taxa from Florida, Papua New Guinea, and India that exhibit similar features is presented.     

Standard electromotive force of the H2-AgCl;Ag cell in 30, 40, and 50 mass% glycerol/water from -20 to 25 degrees C: pK2 and pH values for a standard "mops" buffer in 50 mass% glycerol/water

Data are presented regarding the establishment of the pH (designated pH*) of a standard buffer solution suitable as a pH reference in 50 mass% glycerol/water mixtures at temperatures ranging from -20 to 25 degrees C. The buffer material selected was the ampholyte Mops [(3-N-morpholino)-propane sulfonic acid], and the reference standard consists of equal molal amounts of Mops and its sodium salt. The assignment of pH* values is based on measurements of the electromotive force (emf) of cells without liquid junction of the type: Pt;H2(g, 1 atm) / Mops, Na Mopsate, NaCl / AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Mops) +/- in equilibrium with (Mopsate)- + H+. The standard emf of the silver-silver chloride electrode in 30, 40, and 50 mass% glycerol/water mixtures was determined from emf measurements of the cell at subzero temperatures with HCl solutions replacing the buffer-chloride mixtures.     

Acid dissociation constants and pH values for standard "bes" and "tricine" buffer solutions in 30, 40, and 50 mass% dimethyl sulfoxide/water between 25 and -25 degrees C

Information is given concerning two standard buffer solutions suitable as pH references in 30, 40, and 50 mass% dimethyl sulfoxide (DMSO)/H2O mixed solvents at subzero temperatures from -20 to 0 degrees C, with the intention of establishing a pH (designated pH*) scale. The two buffers selected were the ampholytes N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid ("bes") and N-tris(hydroxymethyl)methylglycine ("tricine"), and the reference standard consisted of equal molal quantities of the buffer and its respective sodium salt. The assignment of pH* values was based on measurements of the emf of cells without liquid junction of the type: Pt;H2(g,l atm) /Bes, Na Besate, NaCl / AgCl;Ag and Pt;H2(g,l atm) /Tricine, Na Tricinate, NaCl /AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Buffer)+/- in equilibrium with(Buffer)- + H+.     

Toxigenic Potential of Some Fusarium Isolates from Southeast Asia

The isolation and characterization of 10 isolates of six Fusarium spp. from plant and soil samples collected in Southeast Asia is reported. The ability of these isolates to produce trichothecenes both in liquid cultures (CZ, GYEP, and MYRO) and on rice was assessed, and their toxigenic potential was examined by skin assay and gavage studies with culture filtrates. Although culture filtrates of all the isolates caused minor damage to test animals, only that of F. equiseti DAOM 189762 produced trichothecenes.