Metabolism of propionic acid by golden delicious apples

The headspace of whole Golden Delicious apples treated with propionic acid vapour, was analysed by means of GC, after enrichment on Tenax GC, and its c     

Toddanol and toddanone,two coumarins from Toddalia asiatica

Two new constituents isolated from the roots of Toddalia asiatica and designated as toddanol and toddanone have been characterized as 5,7-dimethoxy-6-(2-hydroxy-3-methylbut-3-enyl)coumarin (1) and 5,7-dimethoxy-6-(3-methyl-2-oxobutanyl)coumarin (3), respectively, by spectral analysis and interconversion experiments.     

Structural homology of storage proteins coded by the Hor-1 locus of barley (Hordeum vulgare L.)

Three C hordein fractions were prepared by ion-exchange chromatography of a total hordein preparation on carboxymethyl cellulose at pH 4.6 Polyacrylamide gel electrophoresis at pH 3.2 and sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) at pH 8.9 showed that each fraction contained a single major band. The apparent molecular weights of these were determined by SDS-PAGE as 58, 57, and 54,000. When compared by isoelectric focusing, however, the 58 and 57,000 components each separated into two major bands and the 54,000 component into four. Amino acid analysis showed that although the three fractions had similar compositions with high glutamate+glutamine (38–39%), proline (30–32%) and phenylalanine (8–9%) contents, some differences were present, notably in the relative content of lysine. The three fractions had identical amino acid sequences for the first ten residues at the N-terminal end. They also had identical sequences for the first five residues at the C-terminal end, with the exception that a mixture of two amino acids were released from position 4 of the 58,000 fraction only. Peptide mapping with three enzymes (trypsin, chymotrypsin and V8 protease) indicated that the 58 and 57,000 fractions were more closely related to each other than to the 54,000 fraction. It is suggested that the 57 and 58,000 fractions and the 54,000 fraction constitute two families of closely related polypeptides which are coded by genes derived from the duplication and divergence of a single ancestral gene.     

Isolation and analysis of cell wall material from beeswing wheat bran (Triticum aestivum)

Cell wall material (CWM) isolated from beeswing wheat bran contains 66% carbohydrate, 12% Klason lignin, 6% protein and 4% ash. The relative proportions of sugars in the CWM are arabinose 34%, xylose 26%, galactose 2%, glucose 32% and uronic acid 6%. The uronic acid was shown to consist of glucuronic acid and its 4-O-Me analogue in the ratio 1.8:1. Partial acid hydrolysis of the CWM yielded neutral sugars and a uronic acid fraction. The latter was shown to contain Glc p A-(1→2)-Xyl p and Glc p A-(1→2)-O-Xyl p-(1→4)-Xyl p and their 4-O-Me substituted uronic acid analogues. Methylation analysis of the whole CWM and partially degraded methylated CWM revealed the nature of the constituent glycosidic linkages. From the combined evidence we infer that the major structural features of the non-cellulosic polysaccharides are a linear chain of xylopyranose units joined by (1→4)-linkages, and arabinofuranose, xylose, galactose (and uronic acid) end groups, which in at least some of the polysaccharides, are attached directly by (1→2)- and/or (1→3)-linkages to the xylan chain. The CWM has been fractionated by successive extractions with water at 80°, 0.2 M (NH₄)₂C₂O₄ at 80°, Na chlorite/HOAc at 70°, 0.2 M (NH₄)₂C₂O₄ at 80°, 1 M and 4 M KOH, and the neutral sugar composition of the fractions determined. It is concluded from these and other experiments that the CWM contains two main types of polysaccharides, the arabinoxylans and cellulosic polymers, and that phenolic ester linkages play a role in holding them together.     

Cell wall polysaccharides from onions

Onion (Allium cepa) cell walls were fractionated by successive extraction with oxalate-citrate buffer and with alkali. The substantial oxalate-citrate extracted fraction comprised a range of pectic polysaccharides with varying proportions of neutral side-chains. Methylation analysis of the alkali extract indicated that (1,4′)-linked galactans and a substituted xyloglucan were probably major components. Onions thus resemble dicotyledonous plants more than the Gramineae in their cell wall composition.     

Three triterpenes and other terpenoids from Catha cassinoides

The investigation of stems and leaves of Catha cassinoides afforded, in addition to sitosterol, β-amyrin, ursolic acid, lup-20(29)-en-3β,30-diol and friedelin, three new pentacyclic triterpenes: 30-hydroxyfriedelan-3-one, 29-hydroxyfriedelan-3-one and 3-oxo-friedelan-29-oic acid. The structures ofthese were determined by spectral studies and correlations, and were confirmed by X-ray analysis of 29-hydroxyfriedelan-3-one acetate.     

Structural changes in the pars intermedia of the cichlid teleost Sarotherodon mossambicus as a result of background adaptation and illumination

Summary The pars intermedia of Sarotherodon mossambicus contains two structurally different endocrine cell types. The predominant cell type is assumed to synthesize MSH and related peptides. The second cell type is PAS positive; its function and products are unknown. In this second cell type changes occur in relation to background colour and illumination. Thus, PAS positive cells of fish adapted to a white background are less numerous and metabolically less active than those of fish adapted to a black background, and are most active in fish kept in total darkness. In blinded fish, whether in light or in darkness, the activity of the PAS positive cells is similar to that of the black background-adapted animals. The significance of these responses in relation to the control of background adaptation is discussed.     

Composition and function of human cervical mucus

Human cervical mucus was collected from seven donors during the follicular, ovulatory and luteal phases of the ovulatory menstrual cycle. Individual mucus samples were solubilized and fractionated on Sepharose columns into excluded mucins and low-molecular-weight proteins. Mucin fractions were highly purified, as evidenced by the presence of a single N-terminal amino acid residue, threonine, and by the absence of contaminating plasma proteins. Amino acid compositions of mucins isolated during different menstrual phases of a single donor or from different donors were similar. Mucin carbohydrate compositions were also similar, except for the sialic acid-to-fucose ratio, which varied significantly between donors but not within the menstrual cycle of a single donor. An analysis of variance was applied to evaluate the contribution of mucin composition to viscoelasticity, as quantitated by microrheometry. Viscoelasticity was dependent on the donor, on the percent nondialyzable solids and on the mucin content, but not on the phase of the menstrual cycle during which the sample was collected. These findings suggest that mucus function (viscoelasticity) is reflected in carbohydrate composition and/or structure and that this menstrual relationship is unique for each donor. Furthermore, the absence of menstrual phase-dependent differences in mucins suggests that mucin concentration and not composition changes in response to alterations in the hormonal milieu.     

DNA protection with the DNA methylase M . BbvI from Bacillus brevis var. GB against cleavage by the restriction endonucleases PstI and PvuII

BamHI fragments of the Bacillus brevis var. GB plasmid pAD1 have been cloned in Escherichia coli HB101 using pBR322 plasmid as a vector. The analysis of the recombinant plasmids showed that additional PstI sites had appeared in cloned fragments of pAD1. Methylation of the recombinant plasmids in vitro by enzymes from B. brevis GB cells blocks cleavage at these additional PstI sites of cloned pAD1 fragments and at the PstI site of pBR322. Among DNA methylases of B. brevis GB, the cytosine DNA methylase M . BbvI is the most likely agent modifying the recognition sequences of PstI. The methylase can modify cytosine residues in PstI or PvuII sites if these recognition sequences are linked to G at 5'- or to C at 3'-termini. In particular, in vitro methylation of the SV40 DNA by B. brevis GB methylases protects one of the two PstI sites and two of the three PvuII sites. The described effect of the protection of the specific PstI and PvuII sites may be used for physical mapping of genomes and DNA cloning.     

Cytogenetic and electrophoretic evidence for a polyploid origin of the basic chromosome number x = 14 in the genusAsphodelus (Liliaceae)

Cytogenetic and electrophoretic analyses on 2n = 28 strains ofAsphodelus cerasiferus strongly suggest that the basic number x = 14 of the genusAsphodelus is of secondary polyploid origin from x = 7.