Molecular cloning and ethylene-inducible expression of Chib1 chitinase from soybean (Glycine max (L.) Merr.).
(9/3573)
A soybean seed-specific PR-8 chitinase, named Chib2, has a markedly extended C-terminal segment compared to other plant Chib1 homologues of the PR-8 chitinase family known to date. To further characterize the molecular structure and the expression pattern of this chitinase family, we cloned two typical Chib1-similar cDNAs (Chib1-1 and Chib1-2) from soybeans by PCR-cloning techniques. The deduced primary sequence of Chib1-1 chitinase is composed of a signal peptide segment (26 amino acid residues) and a mature 273 amino acid sequence (calculated molecular mass 28,794, calculated pI 3.7). This Chib1-1 enzyme is more than 90% identical to Chib1-2 chitinase but is below 50% identical to Chib2 enzyme. Thus, we confirmed the occurrence of two distinct classes, Chib1 and Chib2 in the plant PR-8 chitinase family. The Chib1 genes, interrupted by one intron, were found to be up-regulated in response to ethylene in stems and leaves, but scarcely expressed in developing soybean seeds. Chib1 chitinases may be responsible for protecting the plant body from various pathogenic attacks. (+info)
Quality and safety evaluation of genetically engineered rice with soybean glycinin: analyses of the grain composition and digestibility of glycinin in transgenic rice.
(10/3573)
The composition of nutritionally and physiologically important molecules in transgenic rice with the soybean glycinin gene was determined and compared with that of a non-transgenic control. Except for the levels of protein, amino acids and moisture, no marked differences were found between the two kinds of rice. The protein content of the transgenic rice was about 20% higher than the control (control, 6.5 g/100 g; transgenic, 8.0 g/100 g) with a concomitantly lower moisture content. This increased protein content mainly resulted from the increased glycinin expressed in the transgenic rice, and the protein was susceptible to gastric and intestinal digestion juices. In parallel with the increased protein content, some important amino acids lacking in quantity in normal rice were replenished. (+info)
Isolation of a French bean (Phaseolus vulgaris L.) homolog to the beta-glucan elicitor-binding protein of soybean (Glycine max L.).
(11/3573)
A high-affinity membrane-bound beta-glucan elicitor-binding protein has been purified from microsomal preparations of French bean (Phaseolus vulgaris L.) roots. A 5900-fold purification was achieved by affinity chromatography of functionally solubilized membrane proteins. The beta-glucan-binding protein had an apparent molecular mass of 78 kDa when subjected to SDS-PAGE. Western blot analysis showed specific crossreactivity of this French bean protein with an antiserum raised against a synthetic peptide representing an internal 15 amino acid fragment of the beta-glucan-binding protein from soybean. Northern blot analysis with a cDNA probe of the soybean beta-glucan-binding protein gene revealed a crosshybridizing transcript of 2.4 kb in French bean. These results indicate that the beta-glucan-binding proteins of French bean and soybean are conserved homologs involved in beta-glucan elicitor recognition. (+info)
An alternative oxidase monoclonal antibody recognises a highly conserved sequence among alternative oxidase subunits.
(12/3573)
The alternative oxidase is found in the inner mitochondrial membranes of plants and some fungi and protists. A monoclonal antibody raised against the alternative oxidase from the aroid lily Sauromatum guttatum has been used extensively to detect the enzyme in these organisms. Using an immunoblotting strategy, the antibody binding site has been localised to the sequence RADEAHHRDVNH within the soybean alternative oxidase 2 protein. Examination of sequence variants showed that A2 and residues C-terminal to H7 are required for recognition by the monoclonal antibody raised against the alternative oxidase. The recognition sequence is highly conserved among all alternative oxidase proteins and is absolutely conserved in 12 of 14 higher plant sequences, suggesting that this antibody will continue to be extremely useful in studying the expression and synthesis of the alternative oxidase. (+info)
Urinary disposition of the soybean isoflavones daidzein, genistein and glycitein differs among humans with moderate fecal isoflavone degradation activity.
(13/3573)
Glycitein metabolism was compared with other isoflavones to begin to understand the effect of this compound. Total isoflavones of 4.5 micromol/kg body weight from soymilk (high in genistein and daidzein) and soygerm (high in daidzein and glycitein) was fed to seven women and seven men. To minimize interindividual variation, only subjects with moderate fecal isoflavone degradation rates (half-lives of daidzein and genistein were 15.7 and 8.9 h, respectively) were included. The average 48-h urinary excretion of glycitein, daidzein and genistein was approximately 55, 46 and 29% of the dose ingested, respectively, which was significantly different from each other in men and women (P < 0.001). Plasma isoflavone concentrations at 6 and 24 h after soymilk feeding paralleled relative amounts of isoflavones in soymilk (genistein > daidzein > glycitein) (P < 0.05) in men and women, but plasma isoflavone concentrations after soygerm feeding did not parallel soygerm isoflavone concentrations in women because genistein and glycitein did not differ from each other at 6 h after feeding. Six hours after soygerm dosing, plasma isoflavone concentrations paralleled soygerm isoflavone levels in men. Based on plasma isoflavone concentrations at 6 h after dosing, the bioavailabilities of daidzein and genistein were similar in men and women. At the high glycitein dose (soygerm), plasma concentration at 24 h after dosing suggested a modest gender difference in glycitein bioavailability. (+info)
Soybean isoflavones reduce experimental metastasis in mice.
(14/3573)
We investigated the effect of dietary supplementation with isoflavones on pulmonary metastasis of B16BL6 murine melanoma cells in C57BL/6 mice. Mice were fed a basal AIN-93G diet or the basal diet supplemented with the isoflavones genistein and daidzein at 113 micromol/kg, 225 micromol/kg, 450 micromol/kg, or 900 micromol/kg for 2 wk before and after the intravenous injection of 0.5 x 10(5) melanoma cells. At necropsy, the number and size of tumors that formed in the lungs were determined. The number of mice that had >15 lung tumors was 17 in the control group, and 16, 15, 13, and 10 in the groups fed isoflavones at 113 micromol/kg, 225 micromol/kg, 450 micromol/kg and 900 micromol/kg, respectively. The latter two were significantly different from the control (P +info)
Absence of limiting amino acids in calves fed a corn and soybean meal diet past three months of age.
(15/3573)
We conducted three nitrogen balance trials using Holstein bull calves older than 16 wk (Trial 1; n = 8), 13 wk (Trial 2; n = 6), and 15 wk of age (Trial 3; n = 9) in a 4 x 4 (Trial 1) or 3 x 3 Latin square design (Trials 2 and 3) to identify limiting amino acids for a corn and soybean meal diet. All calves were trained to maintain reflex closure of the reticular groove after weaning at 5 wk of age. The basal diet was fed daily at 20 or 27 g/kg BW (Trial 1) and at 20 g/kg BW (Trials 2 and 3). The lower feeding level resulted in reduced urinary excretion of purine derivatives, suggesting reduced synthesis of ruminal microbial protein (Trial 1). In Trials 1 and 2, administration of DL-methionine plus L-lysine monohydrochloride through the reticular groove did not increase N retention compared with the supplement of isonitrogenous L-glutamine at either level of intake. In Trial 3, administration of either casein or isonitrogenous monosodium glutamate increased N retention to a similar extent above that observed with a N-free supplement. Results suggested that no specific amino acids were limiting for the corn-soybean meal diet. Administration of methionine plus lysine resulted in a remarkable increase in plasma methionine (Trials 1 and 2), especially at the lower intake level (Trial 1), and a decrease in plasma branched-chain amino acids at either intake level. Glutamine supplementation did not increase plasma branched-chain amino acids compared with the supplementation of diammonium citrate (Trial 2). (+info)
Effect of fiber source on cell wall digestibility and rate of passage in rabbits.
(16/3573)
The influence of fiber source on fiber digestion and mean retention time was investigated. Six fibrous feedstuffs with wide differences in chemical composition and particle size were selected: paprika meal, olive leaves, alfalfa hay, soybean hulls, sodium hydroxide-treated barley straw, and sunflower hulls. Six diets were formulated to contain one of these ingredients as the sole source of fiber. To avoid nutrient imbalances, fiber sources were supplemented with different proportions of a concentrate free of fiber based on soy protein isolate, wheat flour, lard, and a vitamin and mineral mix to obtain diets containing at least 18.5% CP and 5% starch. Fecal apparent digestibility of nonstarch polysaccharides (NSPd) and its monomers, NDF, NDF-ADL, and ADF-ADL, were determined using four New Zealand White x California growing rabbits per diet. Total, ileorectal, and cecal mean retention times (tMRT, i-rMRT, and cMRT, respectively) were determined for diets based on paprika meal, olive leaves, soybean hulls, and sunflower hulls in 16 does (four per diet) fitted with T-cannulas at the terminal ileum. In both trials, DMI was negatively correlated with the proportion of fine particles (FP: < .315 mm) and positively correlated with the proportion of large particles (LP: > 1.25 mm) (P < .01). Stepwise regression analysis showed that FP was the dietary characteristic best related to digestibilities of NSP, uronic acids, glucose and NDF, tMRT, and cMRT (P < .001), showing a positive correlation with these variables. In all these cases, this procedure selected the proportion of large particles as a second variable in the model. Degree of lignification of NDF, considering lignin as the difference between ADL and acid detergent cutin, was only included as the third variable for the model of NDF digestibility. Digestibility of NSP was positively correlated with those of NDF, NDF-ADL, and ADF-ADL (r = .82, .87 and .85, respectively, P < .001); the latter was also highly correlated with the digestibility of the glucose included in the NSP fraction (r = .86; P < .001). Cecal mean retention time accounted for 63% of average tMRT, for most of the variability in tMRT (r = .99; P < .001), and was positively related to NSPd (r = .89; P < .001). From these results, we conclude that particle size is a major factor affecting fiber digestion efficiency, rate of passage, and feed intake in rabbits. (+info)