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PubMed2000

Characterization of methanol-soluble and methanol-insoluble proteins from developing peanut seed.

The 85% methanol-soluble proteins are known to specifically contribute to the production of flavor of roasted peanut. To determine the nature of the 85% methanol-soluble proteins, they were isolated from the peanut seed, and the 85% methanol-soluble (MS) and 85% methanol-insoluble (MIS) fractions were characterized using polyacrylamide gel electrophoresis (PAGE) and capillary electrophoresis. The results showed that the 85% MS fraction contained lower amounts (9-10%) of protein than the MIS fraction (15-33%). Protein content of the MIS fraction increased more significantly during seed maturation than it did in the MS fraction. Unlike the protein, free amino acids and soluble sugars levels of the MS fraction decreased significantly during seed maturation. The 85% MS fraction contained predominantly low molecular weight (<20 kDa) proteins/polypeptides, whereas the MIS fraction contained a mixture of polypeptides with molecular weight between 14 kDa and 90 kDa. SDS-PAGE showed no major changes in the polypeptide composition of the MS fraction during seed maturation. Capillary electrophoretic analysis revealed major qualitative and quantitative changes in the protein and polypeptide composition of the MS and MIS fractions during seed maturation. Fatty acid analysis of these fractions indicated that the MS fraction is lipoprotein in nature and rich in oleic and linoleic acids.

Amino Acids↗
PubMed1992

Maturation proteins and sugars in desiccation tolerance of developing soybean seeds.

The desiccation-tolerant state in seeds is associated with high levels of certain sugars and maturation proteins. The aim of this work was to evaluate the contributions of these components to desiccation tolerance in soybean (Glycine max [L.] Merrill cv Chippewa 64). When axes of immature seeds (34 d after flowering) were excised and gradually dried (6 d), desiccation tolerance was induced. By contrast, seeds held at high relative humidity for the same period were destroyed by desiccation. Maturation proteins rapidly accumulated in the axes whether the seeds were slowly dried or maintained at high relative humidity. During slow drying, sucrose content increased to five times the level present in the axes of seeds held at high relative humidity (128 versus 25 mug/axis, respectively). Stachyose content increased dramatically from barely detectable levels upon excision to 483 mug/axis during slow drying but did not increase significantly when seeds were incubated at high relative humidity. Galactinol was the only saccharide that accumulated to higher levels in axes from seeds incubated at high relative humidity relative to axes from seeds that were slowly dried. This suggests that slow drying serves to induce the accumulation of the raffinose series sugars at a point after galactinol biosynthesis. We conclude that stachyose plays an important role in conferring desiccation tolerance.

Journal Article↗
PubMed1995

Photoaffinity Labeling of Developing Jojoba Seed Microsomal Membranes with a Photoreactive Analog of Acyl-Coenzyme A (Acyl-CoA) (Identification of a Putative Acyl-CoA:Fatty Alcohol Acyltransferase.

Jojoba (Simmondsia chinensis, Link) is the only plant known that synthesizes liquid wax. The final step in liquid wax biosynthesis is catalyzed by an integral membrane enzyme, fatty acyl-coenzyme A (CoA):fatty alcohol acyltransferase, which transfers an acyl chain from acyl-CoA to a fatty alcohol to form the wax ester. To purify the acyltransferase, we have labeled the enzyme with a radioiodinated, photoreactive analog of acyl-CoA, 12-[N-(4-azidosalicyl)amino] dodecanoyl-CoA (ASD-CoA). This molecule acts as an inhibitor of acyltransferase activity in the dark and as an irreversible inhibitor upon exposure to ultraviolet light. Oleoyl-CoA protects enzymatic activity in a concentration-dependent manner. Photolysis of microsomal membranes with labeled ASD-CoA resulted in strong labeling of two polypeptides of 57 and 52 kD. Increasing concentrations of oleoyl-CoA reduced the labeling of the 57-kD polypeptide dramatically, whereas the labeling of the 52-kD polypeptide was much less responsive to oleoyl-CoA. Also, unlike the other polypeptide, the labeling of the 57-kD polypeptide was enhanced considerably when photolyzed in the presence of dodecanol. These results suggest that a 57-kD polypeptide from jojoba microsomes may be the acyl-CoA:fatty alcohol acyltransferase.

Journal Article↗
PubMed1966

Variations in endogenous gibberellins in developing bean seeds I. Occurrence of neutral and acidic substances.

Activities of separated and chromatographed substances in the nonacidic, acidic ethyl acetate and acidic butanol fractions from bean seeds, Phaseolus vulgaris L., cv. Bountiful and Kentucky Wonder, were measured in the Progress No. 9 dwarf pea bioassay grown under red light. Activity in the nonacidic fraction was shown to be attributable only to neutral substances and was free of acidic gibberellin-like substances. As the seed matures, neutral substances and one of the acidic butanol-soluble substances (B-I) increase in activity. The acidic ethyl acetate substances and butanol-soluble substance (B-II) initially increase and then almost disappear.

Journal Article↗
PubMed1975

Characterization of adenosine diphosphate glucose pyrophosphorylases from developing maize seeds.

Electrophoretic examination of 22-day-old, normal maize (Zea mays L.) endosperm extracts revealed two zones of adenosine diphosphate glucose pyrophosphorylase activity. The enzymes are identical in terms of Km for glucose 1-phosphate and the effect of 3-phosphoglyceric acid on apparent Km for glucose 1-phosphate. Both enzymatic activities increase with increasing doses of the functional alleles at the shrunken-2 and brittle-2 loci. Molecular weight differences between the two electrophoretic species were inferred from sucrose gradient centrifugation. It is suggested that the two bands of activity represent different aggregation states of the same enzyme because under different extraction conditions, only one enzyme is found. Molecular weight estimates of 237,000 and 253,000 were obtained for the smaller enzyme. It is suggested that this enzyme is an aggregate of several subunits. Comparison of the embryo and endosperm pyrophosphorylases showed the embryo activity to be more heat stable and probably independent of direct shrunken-2 or brittle-2 control.

Journal Article↗
PubMed1975

Asparagine metabolism-key to the nitrogen nutrition of developing legume seeds.

Asparagine accounted for 50 to 70% of the nitrogen carried in translocatory channels serving fruit and seed of white lupin (Lupinus albus L.). Rates of supply of the amide always greatly exceeded its incorporation as such into protein. An asparaginase (l-asparagine amido hydrolase EC 3.5.1.1) was demonstrated in crude extracts of seeds. In vitro activity was up to 5 mumoles of aspartate formed per hour per gram fresh weight at the apparent Km(Asn) value of 10 mM, and this more than accounted for the estimated rates of asparagine utilization in vivo. Asparaginase activity per seed increased 10-fold in the period 5 to 7 weeks after anthesis, coinciding with early stages of storage protein synthesis in the cotyledons.Double labeled ((14)C (U), (15)N (amide)) asparagine was fed to fruiting shoots through the transpiration steram. Fruit phloem sap analysis indicated that virtually all of the label was translocated to seeds in the form of asparagine. In young seeds (15)N from asparagine breakdown was traced to the ammonia, glutamine, and alanine of endospermic fluid, the (14)C appearing mainly in nonamino compounds. In the cotyledon-filling stage the C and N of asparagine was contributed to a variety of amino acid residues of protein.

Journal Article↗
PubMed1989

Analysis of avenin proteins and the expression of their mRNAs in developing oat seeds.

We have isolated and characterized cDNA clones encoding avenins, the prolamine storage proteins of oat seeds. Sequence analysis shows that avenins are a related group of polypeptides and that their mRNAs differ from each other by point mutations and small insertions and deletions. Avenin proteins have structural homology to the alpha/beta-gliadins and gamma-gliadins of wheat, the B-hordeins of barley, and the gamma-secalins of rye. Hybridization analysis of DNA from various diploid, tetraploid, and hexaploid oat species shows that the oat genome contains more globulin storage protein genes than avenin genes and that some restriction fragments containing these genes are conserved between species with common genomes. We estimate that there are 25 avenin genes and 50 globulin genes per haploid genome in Avena sativa and similar ratios of globulin to avenin genes in other Avena species. Avenin and globulin polypeptides begin to accumulate between 4 days and 6 days after anthesis. Messenger RNAs encoding avenin and globulin proteins become abundant 4 days after anthesis and reach peak concentrations at 8 days after anthesis. Avenin mRNAs are present in somewhat greater molar amounts than globulin mRNAs beginning at 4 days after anthesis. Because there is considerably more globulin than avenin in the mature oat seed, the expression of globulin and avenin genes may be regulated both transcriptionally and post-transcriptionally.

Amino Acid Sequence↗
PubMed2000

[Dynamics of mitotic index of buckwheat root meristems, developing from seeds subjected to percussive wave treatment].

A method of percussive wave treatment of seeds, promoting activization of physiological processes in plants, was proposed. The influence of physical treatment on cell nuclei and phytohormones was investigated. We examined dynamics of mitotic indices (MI) of the root meristems of buckwheat seedlings 48-58 h after the treatment. The seeds were treated with pressures of 11, 23, 29 MPa. The synchrony of cell divisions was estimated according to the augmentation of maximum MI versus average MI. The maximum and the average MI of control seedlings was 9.6 and 8.1%, resp. After the treatment with the pressure of 11 MPa the average MI increased by 2.6 times, and synchrony raised by 50%. After the treatment by the pressure of 23 MPa the average value of MI did not change versus the control, but the synchrony enhanced by 2.8 times. After the treatment of the pressure of 29 MPa the average MI decreased by 31%, the synchrony increased by 33%. Examination of phase indexes allowed to reveal the damage of cytotomy, transition to metaphase, and mitotic apparatus formation. The MI of root meristems of the test seedling aged 8 days topped the control by 21, 156 and 20%. So, the pressure of 11 MPa promoted MI increase in 2 days, and those of 23 and 29 MPa in 8 days. The investigation of hormone balance allowed to detect a raising level of abscisic acid. Its influence on the plant growth depends on the content of zeatin. A hypothetical model of plant reaction mechanism was proposed, based on the obtained results. A momentary pressing in the percussive wave was a stressor, promoting the accumulation of ABA and "growth rest", that changed for an active growth induced by zeatin.

Fagopyrum↗
PubMed2004

Cloning of genes differentially expressed during the initial stage of fruit development in melon (Cucumis melo cv. Reticulatus).

We have cloned genes involved in the initial stage of fruit development in the melon by suppression subtractive hybridization. A cDNA library of unfertilized ovules was subtracted from that of fruit 9 days after pollination (DAP); 10 of the 40 selected cDNA clones were identified by reverse Northern analysis as genes differentially expressed in fruit at 9 DAP. Seven of the ten genes were homologous to genes of known function; two were related to genes with unknown functions, and one was novel. With the exception of cucumisin, none of the cDNAs had been previously identified in melon. According to Northern analyses, six of the genes were expressed at high levels early in fruit development. Expression of cucumisin, Cmf-25, Cmf-30, and Cmf-124 was highest at 9 DAP, implying that these genes are involved in the initial stage of fruit development. Cmf-30, a seed nucellus-specific gene, was also expressed early in seed development. The other genes were expressed at a moderate level throughout fruit development, with the highest expression occurring in fruit at 9 and 18 DAP. In conclusion, nine new genes involved in early fruit development in melon were cloned, and their temporal and spatial expression patterns indicate that they are preferentially expressed during the active growing stage of fruit.

Cloning, Molecular↗
PubMed1985

Endothelium develops on seeded human arterial prosthesis: a brief clinical note.

Despite a considerable and growing body of evidence that endothelial cell seeding accelerates the healing of arterial prostheses in laboratory animals, there has been no histologic evidence thus far to indicate that a similar process occurs in human beings. A case is reported of histologically confirmed, extensive endothelial healing on a polytetrafluoroethylene femoropopliteal bypass graft 90 days after it was seeded and implanted.

Arterial Occlusive Diseases↗