GC-MS identification of GA20-13-O-glucoside formed from GA20 in normal plants and dwarf-1 mutants ofZea mays L.

After feeding GA₂₀ to excised seedlings ofZea mays L. normals (N) and dwarf-1 mutants (d1), GA₂₀-13-O-glucoside (9) was identified by HPLC and by GC-MS of its permethylated derivative. The glucosylation rate of GA₂₀ was found to be higher in the dwarf-1 mutant (26%) than in the normal plant (3.6%). This article includes a GC-MS study in which diagnostic fragments from the spectra of permethylated synthetic GA glucosides have been selected that proved to be useful for the identification of permethylated GA glucosides.     

A new enzymatic pathway of citrullinogenesis in murine hemopoietic cells

Citrullinogenesis is demonstrated when murine bone marrow cells are incubated with dialyzed secondary mixed leukocyte culture supernatant. The identity of citrulline in bone marrow cell supernatants has been established by gas chromatographic mass spectrometric analysis. It is shown that, in our model, citrulline synthesis proceeds directly from arginine without intermediate ornithine production, ruling out the involvement of ornithine transcarbamylase (EC 2.1.3.3.). Moreover, none of the other enzymatic activities described for catalyzing citrullinogenesis, i.e. arginine deiminase or peptidyl arginine deiminase can be demonstrated. The generation of oxygen radicals is necessary for this enzymatic reaction. It is induced by a thermolabile protein produced during the antiallograft immune response with a molecular weight of about 150,000.     

Sexual dimorphism in neuronal projections from the antennae of silk moths (Bombyx mori,Antheraea polyphemus) and the gypsy moth (Lymantria dispar)

Summary The antennal lobe of both sexes of the silk moth Bombyx mori contains 55–60 ventrally located antennal glomeruli; in addition, that of the male contains a dorsal macroglomerular complex (MGC). A group of identifiable glomeruli consisting of two lateral large glomeruli (LLG) and four medial small glomeruli (MSG) is present in both sexes, but the LLG are greatly enlarged in the female. A MGC is also present in the male gypsy moth Lymantria dispar and male giant silk moth Antheraea polyphemus. The MGC in all of these species is organized into 3–4 distinct levels of glomeruli. Antennal sensory fibers were stained by cobalt backfills in B. mori, A. polyphemus, and L. dispar. Most fibers stained from cut long hairs (sensilla trichodea) projected to MGC in males and LLG in both sexes of B. mori. The distribution of fibers in the MGC of B. mori was topographically biased in that a majority of fibers from anterior branches projected medially in MGC while most fibers from posterior branches projected laterally or anteriorly. Terminal arborizations of single fibers were each restricted to a single glomerular level of the MGC. Fibers projecting to the posterior antennal center were frequently stained in cut-hair and control preparations, apparently by uptake of cobalt through intact sensilla on flagellar branches.     

The untranslated leader of nuclear COX4 gene of Saccharomyces cerevisiae contains an intron.

The nuclear gene for subunit IV of cytochrome oxidase (COX4) in Saccharomyces cerevisiae contains a 342 bp intron which is contained entirely within the 5' leader of the message. Splicing of the intron results in removal of several small open reading frames; subsequently, the COX4 AUG becomes the 5' proximal initiation codon. A strain with an rna2- mutation fails to splice mRNA efficiently at restrictive temperature and was used to map the intron splice junctions by RNase protection. Two major mRNA initiation sites were mapped by primer extension of synthetic oligodeoxynucleotides. The splice junctions and internal TACTAAC box conform to consensus sequences previously determined from other yeast introns. One gene for subunit V of cytochrome oxidase (COX5b) has also been shown to contain an intron. The significance of introns in two nuclear genes encoding subunits of cytochrome oxidase is discussed.     

Cost effectiveness of biofeedback and behavioral medicine treatments: a review of the literature

This paper reviews multicomponent behavioral medicine studies that contain cost-effectiveness and or cost-benefit data relevant to the field of biofeedback and relaxation training, primarily when assisted by biofeedback, with or without stress management, in the treatment of psychosomatic illness and pain. A model for evaluating biofeedback treatment is presented. Cost-effectiveness data concerning reduction in physician visits and/or medication use, decrease in medical care costs to patients, reduction in hospital stays and rehospitalization, reduction of mortality, and enhanced quality of life are reviewed. Evidence suggests that multicomponent behavioral medicine treatments are cost-effective on all dimensions reviewed. Cost/benefit ratios range between 1:2 and 1:5, with a median of 1:4. Evidence that could increase the cost effectiveness of biofeedback is reviewed.     

Comparative study of the composition of waxes extracted from isolated leaf cuticles and from whole leaves of Citrus: Evidence for selective extraction

The effect of different extraction methods on the composition of samples of soluble cuticular lipids (SCL) of Citrus aurantium L. was investigated. The variation of extraction yields, when whole leaves were immersed in solvent, was studied as a function of solvent type and duration of immersion. Cuticular waxes were also quantitatively extracted from isolated cuticular membranes of C. aurantium and their composition was compared to that of samples obtained by the immersion method. Significant differences were observed. Higher carbon number homologues of the aliphatic constituent classes were discriminated against when whole C. aurantium leaves were extracted by immersion. The alkyl ester fraction was almost entirely lacking in extracts from whole leaves. The dependence on carbon chain length of the saturation concentrations in chloroform of major aliphatic SCL constituents was determined. The results are discussed in terms of the major physico-chemical processes involved in the extraction of SCL.     

Regulation of intracellular pH by a neuronal homolog of the erythrocyte anion exchanger

We have isolated AE3, a novel gene expressed primarily in brain neurons and in heart. The predicted AE3 polypeptide shares a high degree of identity with the anion exchange and cytoskeletal binding domains of the erythrocyte band 3 protein. Expression of AE3 cDNA in COS cells leads to chronic cytoplasmic acidification and to chloride- and bicarbonate-dependent changes in intracellular pH, confirming that this gene product is an anion exchanger. Characterization of an AE3 mutant lacking the NH2-terminal 645 amino acids demonstrates that the COOH-terminal half of the polypeptide is both necessary and sufficient for correct insertion into the plasma membrane and for anion exchange activity. The NH2-terminal domain may play a role in regulating the activity of the exchanger and may be involved in the structural organization of the cytoskeleton in neurons.     

Genetic and Biochemical Characterization of Mutations Affecting the Ability of the Yeast Pachysolen tannophilus To Metabolize d-Xylose

Induced mutants, selected for their defective growth on d-xylose while retaining the ability to grow normally on d-glucose, were studied in Pachysolen tannophilus, a yeast capable of converting d-xylose to ethanol. Fourteen of the mutations were found to occur at nine distinct loci, and data indicated that many more loci remain to be detected. Most of the mutations were pleiotropic in character, and the expression of some of them was much affected by nutritional conditions and by genetic background. Mutations at several loci resulted in poor growth on at least one compound that was either an intermediate of the tricarboxylic acid cycle, succinate or alpha-ketoglutarate, or on compounds metabolizable via this cycle, ethanol or glycerol. An initial biochemical characterization of the mutants was undertaken. Analysis for xylose reductase, xylitol dehydrogenase, and xylulose kinase activity showed that one or more of these activities was affected in 12 of 13 mutants. However, drastic reduction in activity of a single enzyme was confined to that of xylitol dehydrogenase by mutations at three different loci and to that of d-xylose reductase by mutation at another locus. Growth of these latter four mutants was normal on all carbon sources tested that were not five-carbon sugars.     

Influence of 2-deoxy-D-glucose upon growth and invertase activity of carrot (Daucus carota L.) cell suspension cultures

Carrot (Daucus carota L.) cell suspension cultures grew well when provided with glucose, fructose, sucrose or raffinose. Galactose and melibiose supported less growth unless supplemented with glucose or fructose. In combination with ten different sugar mixtures, 2-deoxy-D-glucose (dGlc) inhibited culture growth. Inhibitory effects of dGlc were more marked with fructose, melibiose, raffinose or mixtures of these sugars in the culture medium. The presence of glucose or galactose reduced the inhibitory effects of dGlc on culture growth. Experiments with radioactive labelled sugars demonstrated that dGLc uptake was greater in the presence of fructose than glucose, and that growth inhibition of dGlc coincided with its uptake. Reduced protein content was also associated with the inhibitory effects of dGlc. Cultured cells contained lower levels of invertase (EC 3.2.1.26) activity during the active phase of culture growth (up to 25 days after subculture) than when growth had peaked and subsequently declined. Acid and alkaline invertase activities were not greatly reduced by exogenous hexoses. Invertase activity was greatest during periods of low protein content in all cultures and was inhibited by dGlc during the latter phases of the culture period. Free intracellular sugars throughout the culture period consisted mainly of glucose and fructose.