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At least 937 records · Page 52Linked to original sources
PubMed1987

Plasma Membrane Lipid Alterations Associated with Cold Acclimation of Winter Rye Seedlings (Secale cereale L. cv Puma).

Highly enriched plasma membrane fractions were isolated from leaves of nonacclimated (NA) and acclimated (ACC) rye (Secale cereale L. cv Puma) seedlings. Collectively, free sterols, steryl glucosides, and acylated steryl glucosides constituted >50 mole% of the total lipid in both NA and ACC plasma membrane fractions. Glucocerebrosides containing hydroxy fatty acids constituted the major glycolipid class of the plasma membrane, accounting for 16 mole% of the total lipid. Phospholipids, primarily phosphatidylcholine and phosphatidylethanolamine with lesser amounts of phosphatidylglycerol, phosphatidic acid, phosphatidylserine, and phosphatidylinositol, comprised only 32 mole% of the total lipid in NA samples. Following cold acclimation, free sterols increased from 33 to 44 mole%, while steryl glucosides and acylated steryl glucosides decreased from 15 to 6 mole% and 4 to 1 mole%, respectively. Sterol analyses of these lipid classes demonstrated that free beta-sitosterol increased from 21 to 32 mole% (accounting for the increase in free sterols as a class) at the expense of sterol derivatives containing beta-sitosterol. Glucocerebrosides decreased from 16 to 7 mole% of the total lipid following cold acclimation. In addition, the relative proportions of associated hydroxy fatty acids, including 22:0 (h), 24:0 (h), 22:1 (h), and 24:1 (h), were altered. The phospholipid content of the plasma membrane fraction increased to 42 mole% of the total lipid following cold acclimation. Although the relative proportions of the individual phospholipids did not change appreciably after cold acclimation, there were substantial differences in the molecular species. Di-unsaturated molecular species (18:2/18:2, 18:2/18:3, 18:3/18:3) of phosphatidylcholine and phosphatidylethanolamine increased following acclimation. These results demonstrate that cold acclimation results in substantial changes in the lipid composition of the plasma membrane.

Journal Article↗
PubMed1988

Carbon dioxide fixation by detached cereal caryopses.

Immature detached cereal caryopses from barley (Hordeum vulgare L. var distichum cv Midas) and wheat (Triticum aestivum L. cv Sicco) were shown to be capable of fixing externally supplied (14)CO(2) in the light or dark. Green cross cells and the testa contained the majority of the (14)C-labeled material. Some (14)C-labeled material was also found in the outer, or transparent, layer and in the endosperm/embryo fraction. More (14)C was recovered from caryopses when they were incubated in (14)CO(2) without the transparent layer, thus suggesting that this layer is a barrier to the uptake of CO(2). In all cases, significant amounts of (14)C-labeled material were found in caryopses after dark incubation with (14)CO(2). Interestingly, CO(2) fixation in the chlorophyll-less mutant Albino lemma was significantly greater in the light than in the dark. The results indicate that intact caryopses have the ability to translocate (14)C-labeled assimilate derived from external CO(2) to the endosperm/embryo. Carboxylating activity in the transparent layer appears to be confined to phosphoenolpyruvate carboxylase activity but that in the chloroplast-containing cross-cells may be accounted for by both ribulose-1,5-bisphosphate carboxylase-oxygenase and phosphoenolpyruvate carboxylase activity. Depending on a number of assumptions, the amount of CO(2) fixed is sufficient to account for about 2% of the weight of starch found in the mature caryopsis.

Journal Article↗
PubMed1988

Photooxidation of Plastids Inhibits Transcription of Nuclear Encoded Genes in Rye (Secale cereale).

Rye (Secale cereale cv Halo) seedlings treated with the herbicide Norflurazon SAN 9789 showed a reduced concentration of mRNA for the small subunit of ribulose-1,5-bisphosphate carboxylase and for the light-harvesting chlorophyll a/b protein. The inhibition of mRNA accumulation by Norflurazon occurred only in the presence of high light intensities and only after a period of days. The primary effect was an inhibition of the transcription rate that occurred within 1 day after exposure of the seedlings to light.

Journal Article↗
PubMed1990

Relationship between Freezing Tolerance of Root-Tip Cells and Cold Stability of Microtubules in Rye (Secale cereale L. cv Puma).

The response of cortical microtubules to low temperature and freezing was assessed for root tips of cold-acclimated and non-acclimated winter rye (Secale cereale L. cv Puma) seedlings using indirect immunofluorescence microscopy with antitubulin antibodies. Roots cooled to 0 or -3 degrees C were fixed for immunofluorescence microscopy at these temperatures or after an additional hour at 4 degrees C. Typical arrays of cortical microtubules were present in root-tip cells of seedlings exposed to the cold-acclimation treatment of 4 degrees C for 2 days. Microtubules in these cold-acclimated cells were more easily depolymerized by a 0 degrees C treatment than microtubules in root-tip cells of nonacclimated, 22 degrees C-grown seedlings. Microtubules were still present in some cells of both nonacclimated and cold-acclimated roots at 0 and -3 degrees C; however, the number of microtubules in these cells was lower than in controls. Microtubules remaining during the -3 degrees C freeze were shorter than microtubules in unfrozen control cells. Repolymerization of microtubules after both the 0 and -3 degrees C treatments occurred within 1 h. Root tips of nonacclimated seedlings had an LT-50 of -9 degrees C. Cold acclimation lowered this value to -14 degrees C. Treatment of 22 degrees C-grown seedlings for 24 h with the microtubule-stabilizing drug taxol caused a decrease in the freezing tolerance of root tips, indicated by a LT-50 of -3 degrees C. Treatment with D-secotaxol, an analog of taxol that was less effective in stabilizing microtubules, did not alter the freezing tolerance. We interpret these data to indicate that a degree of depolymerization of microtubules is necessary for realization of maximum freezing tolerance in root-tip cells of rye.

Journal Article↗
PubMed2003

Evidence that rice and other cereals are ancient aneuploids.

Detailed analyses of the genomes of several model organisms revealed that large-scale gene or even entire-genome duplications have played prominent roles in the evolutionary history of many eukaryotes. Recently, strong evidence has been presented that the genomic structure of the dicotyledonous model plant species Arabidopsis is the result of multiple rounds of entire-genome duplications. Here, we analyze the genome of the monocotyledonous model plant species rice, for which a draft of the genomic sequence was published recently. We show that a substantial fraction of all rice genes ( approximately 15%) are found in duplicated segments. Dating of these block duplications, their nonuniform distribution over the different rice chromosomes, and comparison with the duplication history of Arabidopsis suggest that rice is not an ancient polyploid, as suggested previously, but an ancient aneuploid that has experienced the duplication of one-or a large part of one-chromosome in its evolutionary past, approximately 70 million years ago. This date predates the divergence of most of the cereals, and relative dating by phylogenetic analysis shows that this duplication event is shared by most if not all of them.

Aneuploidy↗
PubMed1982

Immunoglobulin E antibodies to ingested cereal flour components: studies with sera from subjects with asthma and eczema.

The specificity of immunoglobulin E for different cereal grain proteins was investigated using sera from twenty paediatric patients with asthma and/or eczema. Close correlations were observed between radioallergosorbent test values for grain extracts of wheat, rye and barley, and, to a lesser extent, oats. Of the different wheat four fractions tested, the globulins and glutenins consistently bound higher levels of IgE than the gliadins and albumins. This is in contrast both with bakers' asthma (an allergy to inhaled flour where the albumins are important allergens) and with coeliac disease (in which gliadin is the most toxic fraction). Partial digestion of the flour proteins largely removed their ability to bind IgE. An analytical technique of identifying allergens after gel isoelectric focusing demonstrated that many different flour proteins were involved.

Adolescent↗
PubMed1984

Baker's asthma. Studies of the cross-antigenicity between different cereal grains.

Specific IgE antibodies were demonstrated in the sera of six bakers with respiratory symptoms of asthma or bronchitis by the radioallergosorbent (RAST) assay. The specificity of the antibodies was found to be directed not only against the common flours (rye, wheat) used in the bakeries but also against triticale, barley, oat, corn and rice in some of the bakers. By using the RAST inhibition tests, cross-antigenicity was shown to exist between different cereal grains. The degree of cross-reactivity closely paralleled their taxonomic relationship and appeared to be in the following order of decreasing closeness: wheat, triticale, rye, barley, oat, rice and corn. The allergenic activity in the rye and wheat extracts was found to be distributed among various fractions of different molecular weights.

Antibodies, Anti-Idiotypic↗
PubMed2003

Sensory characterization of a ready-to-eat sweetpotato breakfast cereal by descriptive analysis.

The sweetpotato [Ipomoea batatas (L.) Lam], an important industry in the United States, has been selected as a candidate crop to be grown on future long-duration space missions by NASA. Raw sweetpotato roots were processed into flour, which was used to formulate ready-to-eat breakfast cereal (RTEBC). Twelve trained panelists evaluated the sensory attributes of the extruded RTEBC using descriptive analysis. The samples were significantly different (P<0.05) for all attributes. Twelve perceived sensory attributes, which could be used to differentiate the appearance, texture, and flavor of sweetpotato RTEBC, were described. The data could be used to optimize the RTEBC and for designing studies to test its consumer acceptance.

Adolescent↗
PubMed1983

A selective and indicative medium for groups of Penicillium viridicatum producing different mycotoxins in cereals.

A medium, pentachloronitrobenzene-rose bengal-yeast extract-sucrose agar (PRYES), for the isolation of moulds occurring during storage of cereals has been developed and compared with other selective media. The basal medium is yeast extract agar containing 15% sucrose (w/v). In addition to the sucrose content further selective measures include the addition of antibacterial antibiotics chloramphenicol and chlortetracycline (50 mg/l), the fungicides rose bengal (25 mg/l each), and pentachloronitrobenzene (1 g/l) and a low incubation temperature (20 degrees C). Members of the Mucorales were completely inhibited, and fast-growing species of other moulds were slightly inhibited, allowing important storage moulds to develop. The important ochratoxin A and citrinin-producing Penicillium viridicatum group II was indicated by a typical violet brown reverse on PRYES. Producers of xanthomegnin and viomellein (P. viridicatum group I and P. aurantiogriseum) were indicated on PRYES by their yellow reverse and obverse colours. The medium was used for screening 40 samples of barley, and moulds with the characteristic colours were all identified as the species mentioned above.

Citrinin↗
PubMed2005

A secreted lipase of Fusarium graminearum is a virulence factor required for infection of cereals.

Fusarium graminearum is the causal agent of the Fusarium head blight (FHB) and a destructive pathogen of cereals accounting for high grain yield losses especially on wheat and maize. Like other fungal pathogens, F. graminearum secretes various extracellular enzymes, which are hypothesized to be involved in host infection. Extracellular lipolytic activity of F. graminearum was strongly induced in culture by wheat germ oil; this allowed us to isolate, clone, and characterize a gene (FGL1) encoding a secreted lipase. Expression analysis indicated that FGL1 is induced by lipid-containing substrates and repressed by glucose. In planta, FGL1 transcription was detected 1 day post-infection of wheat spikes. The function of the FGL1 gene product was verified by specifically demonstrating lipase activity after expression in a heterologous host. Ebelactone B, a known lipase inhibitor, repressed the lipolytic activity of the enzyme. Disease severity was strongly reduced when wild-type conidia were supplemented with ebelactone B. Transformation-mediated disruption of FGL1 led to reduced extracellular lipolytic activity in culture and to reduced virulence to both wheat and maize.

Fusarium↗
PubMed2005

Hormonal regulation of gluconeogenesis in cereal aleurone is strongly cultivar-dependent and gibberellin action involves SLENDER1 but not GAMYB.

Storage oil is a major constituent in the cereal aleurone layer. The aim of this study was to investigate how gibberellin (GA) and abscisic acid (ABA) regulate conversion of oil to sugar in barley aleurone. The activity of the glyoxylate cycle enzyme isocitrate lyase (ICL) was surveyed in eight barley cultivars. Surprisingly, some cultivars do not require GA for the induction of ICL (e.g. Himalaya), whereas some do (e.g. Golden Promise). Furthermore, in Golden Promise, GA also stimulates triacylglycerol breakdown and enhances the net flux of carbon from acetate to sugar. In contrast, ABA strongly represses ICL activity and the flux of carbon from oil to sugar in both Golden Promise and Himalaya. Biolistics using a promoter reporter showed that GA and ABA regulate ICL at the level of transcription. Studies using barley and rice mutants and pharmacological agents show that GA-dependent induction of ICL activity is mediated by SLENDER1 and requires cGMP, but does not involve the transcription factor GAMYB. Gibberellin and ABA therefore act antagonistically to regulate gluconeogenesis in the aleurone layer as well as controlling the production and secretion of hydrolases into the starchy endosperm. We suggest that the variation between different barley cultivars might be a result of selective breeding to alter seed dormancy.

Abscisic Acid↗
PubMed1996

Interaction of allergens from house-dust mite and from cereal flours: Dermatophagoides pteronyssinus alpha-amylase (Der p 4) and wheat and rye alpha-amylase inhibitors.

Major wheat and rye allergens associated with baker's asthma have been identified as specific inhibitors of Dermatophagoides pteronyssinus alpha-amylase (Der p 4). the most active inhibitors were the wheat tetrameric one and the rye dimeric RDAI-1. these data suggest that interaction between mite and cereal allergens (alpha-amylase/inhibitor complexes) might occur in house-dust-mite-infected flours. In contrast to the strong inhibition of the d. pteronyssinus enzyme by the wheat and rye inhibitors, the amylases from D. farinae, Lepidoglyphus destructor, and Tyrophagus putrescentiae were much less affected. Moreover, the D. pteronyssinus amylase showed higher pH optimum (6.5 versus 5.0) and activity level (2-6 times/mg of protein in whole-mite extracts) than those from the three other mite species.

Allergens↗
PubMed1985

A new type of cereal lectin from leaves of couch grass (Agropyrum repens).

Extracts from couch grass (Agropyrum repens) leaves contain relatively high lectin concentrations. Preliminary experiments with crude extracts indicated that the leaf lectin differs from the embryo lectin of the same species and other Gramineae embryo lectins with respect to its sugar and blood group specificity, and serological properties. A comparison of the biochemical, physicochemical and biological properties of purified lectins from couch grass leaves and embryos, and wheat germ agglutinin revealed that the leaf lectin has the same molecular structure as the embryo lectins. It is a dimer composed of two identical subunits, which, however, are slightly larger than embryo lectin subunits. Structural differences between both couch grass lectins were further inferred from in vitro subunit exchange experiments and serological analyses. Whereas the embryo lectin readily forms heterodimers with embryo lectins from other cereal species and also is serologically indistinguishable from them, the leaf lectin does not exchange subunits with the same embryo lectins and is serologically different. In addition, couch grass leaf lectin exhibits specificity for N-acetylgalactosamine and agglutinates preferentially blood-group-A erythrocytes whereas the embryo lectin is not inhibited by N-acetylgalactosamine and exhibits no blood-group specificity. It was observed also that the lectin content of couch grass leaves varies enormously during the seasons.

Amino Acids↗
PubMed2006

A dynamic model of Rubisco turnover in cereal leaves.

A simple, improved model of Rubisco synthesis and degradation in cereal leaves is developed using data obtained over the leaf lifespan to return maximum likelihood values for Rubisco proteolysis and biosynthesis. It assumes that the time course of leaf Rubisco content can be described using a log-normal curve, and degradation of the Rubisco pool occurs exponentially. Curve parameters give an insight into how Rubisco dynamics differ among treatments or genotypes; also, statistical analyses can be performed more easily, requiring fewer data and allowing more flexibility in sampling than previous studies. Predicted patterns of synthesis correlate well with independent rbc gene transcript data. Rubisco degradation is a first-order decay process, and biosynthesis correlates with leaf elongation rates. As Rubisco degradation takes place according to first-order kinetics, control of leaf Rubisco concentration must be exerted by adjustment of biosynthetic, rather than proteolytic, rates.

Data Interpretation, Statistical↗
PubMed2006

Cereal rust fungi genomics and the pursuit of virulence and avirulence factors.

Rust diseases cause significant reductions annually in yield of cereal crops worldwide. Traditional monoculture cropping systems apply significant selection pressure on the pathogen to cause rapid shifts in pathotypes. Plant breeders strive to stay ahead of the evolving pathogens by releasing new crop genotypes with new rust resistance genes or gene combinations. Owing to the limited number of known resistance genes and the lack of molecular understanding of the plant-pathogen interaction, rusts remain challenging organisms to study, both at organismal and molecular levels. This review discusses recent progress by a number of laboratories towards better understanding the molecular component of rust disease resistance.

Basidiomycota↗
PubMedDate not supplied

Acid anion profiles in dental plaque following consumption of cereal-based foods and fruits.

The aim of this study was to investigate the acid anions produced in plaque after chewing various cereal-based foods and fruits for one minute. Test foods were oranges, apples, bananas, Cornflakes, Branflakes, Weetabix, Alpen, white bread, wholemeal bread, rice and spaghetti, plus positive and negative controls of 10% sucrose and 10% sorbitol. 4 males and 3 females, aged 22-37 years, participated in the study .7 min from the start of chewing, 48-h plaque was collected from all accessible smooth surfaces, with no attempt to collect interproximal plaque, and centrifuged. Plaque fluid was withdrawn and analyzed by isotachophoresis for formate, succinate, lactate, acetate and propionate. At rest, acetate was the major anion present in plaque fluid, whereas following carbohydrate consumption, highest levels of lactate were detected followed by acetate. The amount of lactate only, detected in plaque fluid, was significantly correlated to the carbohydrate present in the food. It was concluded that important information regarding the acidogenicity of test foods is gained by studying the acid anion profile of plaque fluid.

Acetates↗
PubMed1990

Natural occurrence of mycotoxins in some cereals.

Thirty samples each of wheat and rice and 22 of maize were screened qualitatively and quantitatively for the presence of mycotoxins out of which 13, 15 and 7 samples respectively were found to be contaminated with different mycotoxins. Aflatoxin was present in 37.4% samples and besides aflatoxin, ochratoxin A, sterigmatocystin, citrinin, rubratoxin and zearalenone were also present in the cereals. The quantity of aflatoxin was highest in rice samples in comparison to wheat and maize. During the preliminary bioassay no external changes were observed in the mice except for slight weight loss when fed with grain samples, while a high rate of mortality was observed when treated with lethal doses of mycotoxins.

Animals↗
PubMed1985

In vitro adhesion of n(2)-fixing enteric bacteria to roots of grasses and cereals.

Nitrogen-fixing Klebsiella and Enterobacter strains isolated from several plants were assayed for fimbriae and for adhesion to plant roots in vitro. All eight Klebsiella strains formed type 3 fimbriae, and five strains also formed type 1 fimbriae; all 21 Enterobacter strains had type 1 fimbriae. Three strains of Klebsiella carrying either type 1, type 3, or no fimbriae were used as model organisms in developing an in vitro adhesion test. Adhesion was assayed with bacterial cells labeled with [H]leucine. Fifteen N(2)-fixing strains and the three model strains were compared for adhesion to the roots of seven grasses and five cereals. Type 3-fimbriated Klebsiella strains adhered better than the other strains, and type 3 fimbriae appeared to be major adhesins for the Klebsiella strains. Although variations between plants were observed, no host specificity for bacterial adhesion was found.

Journal Article↗