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PubMed2005

Seed-specific expression of the lysine-rich protein gene sb401 significantly increases both lysine and total protein content in maize seeds.

The sb401 gene from potato (Solanum berthaultii) encoding a pollen-specific protein with high lysine content was successfully integrated into the genome of maize plants, and its expression was correlated with increased levels of lysine and total protein content in maize seeds. A plasmid vector containing the sb401 gene under the control of a maize seed-specific expression storage protein promoter (P19z) was constructed and introduced into maize calli by microprojectile bombardment. The integration of the sb401 gene into the maize genome was confirmed by Southern blot analysis, and its expression was confirmed by Western blot analysis. Quantification of the lysine and protein contents in R1 maize seeds showed that, compared with the nontransgenic maize control, the lysine content increased by 16.1% to 54.8% and the total protein content increased by 11.6% to 39.0%. There were no visible morphological changes in the vegetative parts and seeds of the transgenic maize plants. Lysine and protein analysis of the transgenic maize grains showed that the levels of lysine and total protein remained high for six continuous generations, indicating that the elevated lysine and total protein levels were heritable. These results indicate that the sb401 gene could be successfully employed in breeding programs aimed at improving the nutritional value of maize.

Consumer Product Safety↗
PubMed1991

Characterization of 2S seed storage protein of Brassica campestris and its antigenic homology with seed proteins of other Cruciferae.

The low molecular weight seed storage protein of Brassica campestris has been isolated and its amino acid composition determined. Antibody raised against this low molecular weight protein has been used to compare the antigenic similarity between the low molecular weight storage proteins of different Cruciferae seeds by immunoprecipitation and Western blotting. These studies revealed the existence of antigenically homologous proteins of identical molecular weights in seeds of other Cruciferae but absent in some other dicots like mung bean and tobacco seeds.

Amino Acids↗
PubMed1995

Susceptibility of some pea cultivars to pea seed-borne mosaic virus infection and virus transmission by seeds.

The susceptibility of 19 pea cultivars to pea seed-borne mosaic virus (PSbMV) by mechanical inoculation and the virus transmission by seeds were determined. All tested cultivars were highly susceptible to the virus infection. The virus transmission by seeds was found in 1.9% - 32.7%. A correlation between mechanical and vector-mediated infections of pea and virus transmission by seeds is discussed.

Mosaic Viruses↗
PubMed2006

Cells seeded on MBG scaffold survive impaction grafting technique: Potential application of cell-seeded biomaterials for revision arthroplasty.

The objective of this study was to investigate the potential application of cell-seeded biomaterials for revision arthroplasty and the reconstruction of major joints using the impaction grafting technique. Using morselized cancellous bone graft as a porous scaffold, MG63 cells were seeded on the scaffold and impacted into an acetabulum cup model using a mechanical device constructed from data obtained during impaction grafting by an orthopedic surgeon. Immediately after impaction, cells were trypsinized from the scaffold and processed for cell survival rates using the double-stranded DNA PicoGreen assay. Significant reductions in viable cells were observed between the fifth impact and both the first and second impacts (p < 0.01 and p < 0.05, respectively). Cell survival rate was 21.5% after five impacts. The biological performance of cell-seeded biomaterials may be enhanced by these surviving cells. Compared to allograft bone that is not osteogenic, a cell-seeded biomaterial might also be a suitable substitute for allograft bone for major joint reconstruction at revision arthroplasty.

Animals↗
PubMed1997

The Crystallization of Fluorapatite in the Presence of Hydroxyapatite Seeds and of Hydroxyapatite in the Presence of Fluorapatite Seeds

The kinetics of growth of crystals induced by hydroxyapatite (HAP) seed crystals in supersaturated solutions of fluorapatite and of fluorapatite (FAP) seed crystals in supersaturated solutions of hydroxyapatite have been studied using the constant composition method. The reactions were investigated at relative supersaturations ranging from sigmaFAP = 0.99 to 12.0 at pH 6.5 and for HAP, sigmaHAP = 3.6 to 12.6 at pH 7.4. In FAP-supersaturated solutions, this phase was nucleated at the HAP surfaces and underwent growth at a rate more than three times greater than that on FAP seed crystals of equivalent surface area. Transmission electron microscopy (TEM) and electron diffraction imaging clearly demonstrated that the new needle-like HAP phase originated at the FAP surface with the 002 planes of HAP growing on FAP. In contrast, the mutual orientation of FAP crystallization on HAP seed crystals could not be established. Interfacial energies of FAP, HAP, and octacalcium phosphate (OCP) microcrystals against aqueous solutions were obtained by using a thin-layer wicking technique. The interfacial energy values measured in pure aqueous solutions were 18.5, 9.0, and 4.3 mJ m-2 for FAP, HAP, and OCP, respectively. The much smaller value for OCP as compared with the other phases may explain why this phase has been so frequently implicated as a possible precursor to the formation of apatite, especially in biological mineralization reactions.

Journal Article↗
PubMed1992

Rice seed globulin: a protein similar to wheat seed glutenin.

The globulin of the seed endosperms of rice has an isoelectric point of 6.4 and a M(r) of 26,000. There is one intra-disulphide bond, but no N-linked oligosaccharide chain. The amino acid sequence of the N-terminal and internal regions of the globulin was determined and found to be homologous with that of glutenin, the storage protein in the seed endosperms of wheat. Rice globulin and wheat glutenin were rich in glycine, and glutamic acid or glutamine, and in addition, wheat glutenin cross-reacted with antibody raised against rice globulin. These results suggest that rice seed globulin represents a protein similar to wheat seed glutenin.

Amino Acid Sequence↗
PubMed1995

The core Alzheimer's peptide NAC forms amyloid fibrils which seed and are seeded by beta-amyloid: is NAC a common trigger or target in neurodegenerative disease?

BACKGROUND: NAC is a 35-amino-acid peptide which has been isolated from the insoluble core of Alzheimer's disease (AD) amyloid plaque. It is a fragment of alpha-synuclein (or NACP), a neuronal protein of unknown function. We noted a striking sequence similarity between NAC, the carboxyl terminus of the beta-amyloid protein, and a region of the scrapie prion protein (PrP) which has been implicated in amyloid formation. RESULTS: NAC was prepared by chemical synthesis and was found to form amyloid fibrils via a nucleation-dependent polymerization mechanism. NAC amyloid fibrils effectively seed beta 1-40 amyloid formation. Amyloid fibrils comprising peptide models of the homologous beta and PrP sequences were also found to seed amyloid formation by NAC. CONCLUSIONS: The in vitro model studies presented here suggest that seeding of NAC amyloid formation by the beta-amyloid protein, or seeding of amyloid fibrils of the beta-amyloid protein by NAC, may occur in vivo. Accumulation of ordered NAC aggregates in the synapse may be responsible for the neurodegeneration observed in AD and the prion disorders. Alternatively, neurodegeneration may be caused by the loss of alpha-synuclein (NACP) function.

Amino Acid Sequence↗
PubMed2005

Molecular and phenotypic analysis of a working seed lot of yellow fever virus 17DD vaccine strain produced from the secondary seed lot 102/84 with an additional passage in chicken embryos.

Over the last 17 years, the yellow fever (YF) 17DD vaccine secondary seed lot 102/84 was used to produce many million doses of vaccine but it was recently used up. In the absence of other lots at the same passage level a large vaccine batch produced from 102/84 was turned into a new working seed. This new seed was characterized with regard to attenuation in the recommended internationally accepted monkey neurovirulence test (MNVT) using the 102/84 virus as reference. All rhesus monkeys (Macaca mulatta) developed limited viremia and comparable neutralizing antibody titers. Clinical evaluation and histological examination of the central nervous system (CNS) according to WHO criteria for acceptability gave consistent data that demonstrated an attenuated phenotype for the YF 17DD 993FB013Z (13Z) vaccine batch. It is concluded that the additional chicken embryo passage did not lead to any genetic change and the new working seed virus retained its attenuation for monkeys comparable to the 102/84 reference virus.

Animals↗
PubMed1968

Phytochrome and seed germination. V. Changes of phytochrome content during the germination of cucumber seeds.

Cucumber seeds are light-sensitive, dark-germinating seeds. Inhibition of germination can be induced by prolonged exposure to continuous or intermittent FR. The dark germination process and the response to FR are phytochrome controlled. Phytochrome can be detected in these seeds by differential spectrophotometry in vivo. Spectrophotometrically measurable phytochrome increases during dark germination. The rate of increase is temperature dependent. Light treatments which are inhibitory for germination result in phytochrome contents lower than those of the seeds germinating in darkness. Treatments which restore germination also restore phytochrome formation.

Journal Article↗
PubMed1969

Imbibition temperature sensitivity of lima bean seeds controlled by initial seed moisture.

Excised embryonic axes and whole seeds of Phaseolus lunatus L. were previously shown to be injured if exposed to low (5 degrees -15 degrees ) temperature during the initial stages of imbibition. Present data show that this chilling injury during imbibition of liquid water can be prevented if axes are first allowed to absorb water vapor. The increase of initial water content to 20% increases growth even of unchilled axes, and reduces leaching of 264 mmu absorbing compounds. Protection resulting from increased water content is at first independent of the temperature at which water vapor was absorbed. However, longer exposure of high moisture axes to low temperature results in typical chilling injury. The response to initial seed moisture is repeatedly reversible with changes in water content. Because the same response occurs in intact seeds, it may be possible both to protect them against low temperature injury and to increase vigor by increasing seed water-content prior to planting.

Journal Article↗
PubMed1975

Changes in Catechol Oxidase and Permeability to Water in Seed Coats of Pisum elatius during Seed Development and Maturation.

In the developing seed coat of Pisum elatius, o-dihydroxyphenols are present in appreciable amounts at all stages of development. However, catechol oxidase activity rises sharply during the later stages of development, shows a further abrupt rise during dehydration of the seed coat, and then decreases. It is suggested that a tanning reaction is induced by the contact of enzyme with its substrate while cell membranes are ruptured, and that this reaction renders the seed coats impermeable. The entire chain of events does not occur in Pisum sativum which has permeable seed coats.

Journal Article↗
PubMed1991

Anthocyanidins and Flavonols, Major nod Gene Inducers from Seeds of a Black-Seeded Common Bean (Phaseolus vulgaris L.).

Eleven compounds released from germinating seeds of a black-seeded bean (Phaseolus vulgaris L., cv PI165426CS) induce transcription of nod genes in Rhizobium leguminosarum biovar phaseoli. Aglycones from 10 of those compounds were identified by spectroscopic methods (ultraviolet/visible, proton nuclear magnetic resonance, and mass spectroscopy), and their biological activities were demonstrated by induction of beta-galactosidase activity in R. leguminosarum strains containing nodA-lacZ or nodC-lacZ fusions controlled by R. leguminosarum biovar phaseoli nodD genes. By making comparisons with authentic standards, the chemical structures for aglycones from the 10 molecules were confirmed as being anthocyanidins (delphinidin, petunidin, and malvidin) and flavonols (myricetin, quercetin, and kaempferol). All anthocyanidins and flavonols had 3-O-glycosylation and free hydroxyl groups at the 4', 5, and 7 positions. Hydrolysis experiments showed that the mean concentration required for half-maximum nod gene induction (I(50)) by the 10 glycosides was about half that of the corresponding aglycones. The mean I(50) value for the three anthocyanidins (360 nanomolar) was less (P </= 0.05) than that of the three flavonol aglycones (980 nanomolar). Each seed released approximately 2500 nanomoles of anthocyanidin and 450 nanomoles of flavonol nod gene inducers in conjugated forms during the first 6 hours of imbibition. Based on amounts and activities of the compounds released, anthocyanins contributed approximately 10-fold more total nod-inducing activity than flavonol glycosides. These anthocyanidins from bean seeds represent the first nod-inducing compounds identified from that group of flavonoids.

Journal Article↗
PubMed1994

A Model for Seed Transmission of a Plant Virus: Genetic and Structural Analyses of Pea Embryo Invasion by Pea Seed-Borne Mosaic Virus.

Pea seed-borne mosaic virus (PSbMV), a seed-transmitted virus in pea and other legumes, invades pea embryos early in development. This process is controlled by maternal genes and, in a cultivar that shows no seed transmission, is prevented through the action of multiple host genes segregating as quantitative trait loci. These genes control the ability of PSbMV to spread into and/or multiply in the nonvascular testa tissues, thereby preventing the virus from crossing the boundary between the maternal and progeny tissues. Immunocytochemical and in situ hybridization studies suggested that the virus uses the embryonic suspensor as the route for the direct invasion of the embryo. The programmed degeneration of the suspensor during embryo development may provide a transient window for embryo invasion by the virus and could explain the inverse relationship between the age of the mother plant for virus infection and the extent of virus seed transmission.

Journal Article↗
PubMed2006

Potential impact of prostate edema on the dosimetry of permanent seed implants using the new 131Cs (model CS-1) seeds.

Our aim in this work was to study the potential dosimetric effect of prostate edema on the accuracy of conventional pre- and post-implant dosimetry for prostate seed implants using the newly introduced 131Cs seed, whose radioactive decay half-life (approximately 9.7 days) is directly comparable to the average edema resolution half-life (approximately 10 days) observed previously by Waterman et al. for 125I implants [Int. J. Radiat. Oncol. Biol. Phys. 41, 1069-1077 (1998)]. A systematic calculation of the relative dosimetry effect of prostate edema on the 131Cs implant was performed by using an analytic solution obtained previously [Int. J. Radiat. Oncol. Biol. Phys. 47, 1405-1419 (2000)]. It was found that conventional preimplant dosimetry always overestimates the true delivered dose as it ignores the temporary increase of the interseed distance caused by edema. The overestimation for 131Cs implants ranged from 1.2% (for a small edema with a magnitude of 10% and a half-life of 2 days) to approximately 45% (for larger degree edema with a magnitude of 100% and a half-life of 25 days). The magnitude of pre- and post-implant dosimetry error for 131Cs implants was found to be similar to that of 103Pd implants for typical edema characteristics (magnitude < 100%, and half-life <25 days); both of which are worse compared to 125I implants. The preimplant dosimetry error for 131Cs implants cannot be compensated effectively without knowing the edema characteristics before the seed implantation. On the other hand, the error resulted from a conventional post-implant dosimetry can be minimized (to within +/-6%) for 131Cs implants if the post-implant dosimetry is performed at 10+/-2 days post seed implantation. This "optimum" post-implant dosimetry time is shorter than those determined previously for the 103Pd and 125I implants at 16+/-4 days and 6+/-1 weeks, respectively.

Brachytherapy↗
PubMed1993

cis-acting regulatory regions of the soybean seed storage 11S globulin gene and their interactions with seed embryo factors.

A 2.2 kb fragment containing the 5'-flanking region of the soybean glycinin A2B1a gene and its successive deletions with a shorter 5'-flanking sequence were fused, in frame, to the beta-glucuronidase (GUS) reporter gene. The resultant fusions were introduced into tobacco plants via Agrobacterium tumefaciens. Assays of the GUS activity in seeds of transgenic tobacco showed that the upstream region, -657 to -327 (relative to the transcription initiation site [+1]), of the glycinin gene is required for optimal expression of the transformed gene. Interactions between embryo nuclear factors and DNA fragments covering the downstream region of -326, in which are included the TATA box and legumin boxes, were not apparent. The embryo factors capable of binding specifically to three subregions, -653 to -527, -526 to -422, and -427 to -321, of the upstream regulatory region were detected. Such factors appeared to be organ-specific and could be found solely in developing seeds at the early middle stage of embryogenesis (around 24 days after flowering). Evidence obtained by characterizing the nature of the binding proteins and by gel mobility shift assays established that the same factor does interact with a consensus motif 5'-ATA/TATTTCN-/CTA-3' which occurs four times in the cis-acting regulatory region between -657 and -327. Moreover, this conserved motif could also be found in the 5' regulatory region of another glycinin A1aB1b gene. Thus it is likely that the observed interaction between the nuclear factor and the conserved motifs would lead to activation of transcription from the glycinin genes in maturing soybean seeds.

Base Sequence↗
PubMed2006

Geographic variations in seed dispersal by ants: are plant and seed traits decisive?

The effect of local ant species on the dispersal success of a myrmecochorous plant, Helleborus foetidus, was analyzed in two populations of the Iberian Peninsula (Caurel and Cazorla, respectively). The contribution of the various local ant species to dispersal was very unequal. While 5 and 19 ant taxa visited the plants of Caurel and Cazorla, respectively, most removal activity (67 and 80%) was performed by two species only (Formica lugubris and Camponotus cruentatus, respectively). Visits by dispersers were also unequally distributed between neighboring plants. While some plants were always visited during the period of seed release, others were never visited. A regression model indicated that this pattern might be explained by two plant traits: ants preferred to visit plants that released more seeds and whose elaiosomes were richer in oleic acid. Although it has long been known that this compound triggers removal by ants, it is the first demonstration that quantitative variations in elaiosome traits contribute to variation in dispersal success. Finally, other variables being equal, morphological traits (seed size, elaiosome size, and elaiosome/seed size ratio) did not affect ant behavior. Although myrmecochory has long been considered a diffuse interaction, our results support the idea that, at local scale, a limited number of ant species may be decisive to its evolution.

Animals↗
PubMed2005

Cytosolic pyruvate kinase: subunit composition, activity, and amount in developing castor and soybean seeds, and biochemical characterization of the purified castor seed enzyme.

Antibodies against Brassica napus cytosolic pyruvate kinase (PKc) (EC 2.7.1.40) were employed to examine PKc subunit composition and developmental profiles in castor and soybean seeds. A 56-kDa immunoreactive polypeptide was uniformly detected on immunoblots of clarified extracts from developing castor endosperm or soybean embryos. Maximal PKc activities occurred early in castor oil seed (COS) and soybean development (7.1 and 5.5 (micromol of pyruvate produced/min) g(-1) FW, respectively) and were up to 25-fold greater than those of fully mature seeds. Time-course studies revealed a close correlation between extractable PKc activity and the relative amount of the immunoreactive 56-kDa PKc polypeptide. PKc from developing COS was purified 1,874-fold to homogeneity and a final specific activity of 73.1 (micromol of pyruvate produced/min) mg(-1) protein. Gel filtration and SDS-PAGE indicated that this PKc exists as a 230-kDa homotetramer composed of 56-kDa subunits. The mass fingerprint of tryptic peptides of the 56-kDa COS PKc subunit best matched three putative PK(c)s from Arabidopsis thaliana. The purified enzyme was relatively heat-stable and displayed a broad pH optimum of 6.4. However, more efficient substrate utilization (in terms of Vmax /Km for phosphoenolpyruvate or ADP) was observed at pH 7.4. Glutamate was the most effective inhibitor, whereas aspartate functioned as an activator by partially relieving glutamate inhibition. Together with our previous studies, the results: (1) allow a model to be formulated regarding the coordinate allosteric control of PKc and phosphoenolpyruvate carboxylase by aspartate and glutamate in developing COS, and (2) provide further biochemical evidence that castor plant PKc exists as tissue-specific isozymes that exhibit substantial differences in their respective physical and regulatory properties.

Allosteric Regulation↗
PubMed2004

Fertility following fixed-time AI in CIDR-treated beef heifers given GnRH or estradiol cypionate and fed diets supplemented with flax seed or sunflower seed.

The objectives were to determine pregnancy rates following fixed-time AI (FTAI) in heifers: (1). given GnRH or estradiol cypionate (ECP) to synchronize follicular wave emergence and ovulation in a CIDR-based protocol; and (2). fed diets supplemented with flax or sunflower seeds. At two locations, Angus and crossbred Angus heifers (n=983) were examined ultrasonically to confirm reproductive maturity and randomly allocated to six synchronization groups in a 2 x 3 factorial design. On Day 0 (start of synchronization treatments), heifers received a CIDR and either 100 microg GnRH i.m. (n=492) or 1mg ECP plus 50 mg progesterone i.m. (n=491); in these groups, CIDR removal and PGF treatment were done concurrently on Days 7 and 8.5, respectively. Heifers were re-randomized to receive 0.5 mg ECP i.m. at CIDR removal or 24 h later (with FTAI 58-60 h after CIDR removal in both groups), or 100 microg GnRH i.m. concurrent with FTAI (52-54 h after CIDR removal). The heifers were fed a barley silage-based diet for 50 days (from Day -25 to 25) supplemented with 1kg/heifer per day of flax seed (n=321), sunflower seed (n=324), or no oilseed (n=338). Pregnancy rate to FTAI (overall, 56.2%) was not affected by treatment at CIDR insertion (P = 0.96) but was higher (P < 0.05) in heifers given ECP 24h after CIDR removal (216/330, 65.4%) than in those given either ECP at CIDR removal (168/322, 52.1%) or GnRH at AI (169/331, 51.1%). Overall, there was no effect of diet on pregnancy rates (P = 0.46). In summary, pregnancy rate to FTAI was not significantly affected by treatment at CIDR insertion to synchronize follicular wave emergence, but 0.5mg ECP 24h after CIDR removal (to synchronize ovulation) resulted in the highest pregnancy rate.

Animals↗