Interactions of dietary fats and proteins on fatty acid composition of immune cells and LTB4 production by peritoneal exudate cells of rats.
(65/910)
The interaction of dietary fats and proteins on lipid parameters of rats was studied using safflower oil (linoleic acid-rich), borage oil (gamma-linolenic acid-rich) or perilla oil (alpha-linolenic acid-rich) in combination with casein or soybean protein. The experiment was focused on the fatty acid composition of immune cells and the leukotriene B4 production by peritoneal exudate cells. Serum total cholesterol, triglyceride, and phospholipid levels were low in perilla oil-fed or soybean protein-fed rats. Fatty acid compositions of serum and liver phospholipids reflected those of dietary fats. However, feeding borage oil resulted in a marked increase in the proportion of dihomo-gamma-linolenic acid in phospholipids of peritoneal exudate cells, spleen lymphocytes, and mesenteric lymph node lymphocytes in relation to those of liver and serum. It is suggested that activities of metabolic n-6 polyunsaturated fatty acids are different between immune and other tissues. In addition, the magnitude of the reduction of the proportion of linoleic acid of perilla oil in immune cells was considerably more moderate than serum and liver, indicating a different degree of interference of alpha-linolenic acid with linoleic acid metabolism. Leukotriene release from peritoneal exudate cells was in the order of safflower oil > borage oil > perilla oil groups as reflecting the proportion of arachidonic acid, and tended to be lower in soybean protein-fed groups. These suggest an anti-inflammatory property of gamma-linolenic acid as well as alpha-linolenic acid tended to be strengthened when they were combined with soybean protein than with casein. (+info)
Dietary factors and lung cancer risk in Japanese: with special reference to fish consumption and adenocarcinomas.
(66/910)
To investigate risk modification for lung cancer with diet in Japanese, we conducted a hospital-based case-control study and evaluated variation in influence with the histological type. We recruited 367 male and 240 female cases with adenocarcinomas, and 381 male and 57 female cases with squamous cell and small cell carcinomas. Controls comprised 2964 male and 1189 female cancer-free outpatients matched for sex and age with the cases. Odds ratios (ORs) and their 95% confidence intervals (CIs) for lung cancer were calculated with adjustment for potential confounding factors, using an unconditional logistic model. We found decreased ORs for adenocarcinomas in both males (OR = 0.51, 95% CI 0.31-0.84) and females (OR = 0.48, 95% CI 0.24-0.94) who consumed cooked/raw fish, but not dried/salted fish at the highest quartile frequency, compared with the lowest. Soybean curd consumption was associated with a decreased OR for female adenocarcinomas. Decreased ORs for squamous cell and small cell carcinomas were observed in males with frequent consumption of raw and green vegetables, fruit and milk, but consumption of carrot, pumpkin, egg and coffee was associated with increased ORs. This study suggests cooked/raw fish consumption lowers the risk of adenocarcinoma of the lung in Japanese. (+info)
Cosuppression of the alpha subunits of beta-conglycinin in transgenic soybean seeds induces the formation of endoplasmic reticulum-derived protein bodies.
(67/910)
The expression of the alpha and alpha' subunits of beta-conglycinin was suppressed by sequence-mediated gene silencing in transgenic soybean seed. The resulting seeds had similar total oil and protein content and ratio compared with the parent line. The decrease in beta-conglycinin protein was apparently compensated by an increased accumulation of glycinin. In addition, proglycinin, the precursor of glycinin, was detected as a prominent polypeptide band in the protein profile of the transgenic seed extract. Electron microscopic analysis and immunocytochemistry of maturing transgenic soybean seeds indicated that the process of storage protein accumulation was altered in the transgenic line. In normal soybeans, the storage proteins are deposited in pre-existing vacuoles by Golgi-derived vesicles. In contrast, in transgenic seed with reduced beta-conglycinin levels, endoplasmic reticulum (ER)-derived vesicles were observed that resembled precursor accumulating-vesicles of pumpkin seeds and the protein bodies accumulated by cereal seeds. Their ER-derived membrane of the novel vesicles did not contain the protein storage vacuole tonoplast-specific protein alpha-TIP, and the sequestered polypeptides did not contain complex glycans, indicating a preGolgi and nonvacuolar nature. Glycinin was identified as a major component of these novel protein bodies and its diversion from normal storage protein trafficking appears to be related to the proglycinin buildup in the transgenic seed. The stable accumulation of proteins in a protein body compartment instead of vacuolar accumulation of proteins may provide an alternative intracellular site to sequester proteins when soybeans are used as protein factories. (+info)
Protease C2, a cysteine endopeptidase involved in the continuing mobilization of soybean beta-conglycinin seed proteins.
(68/910)
The protease that degrades the beta subunit of the soybean (Glycine max (L.) Merrill) storage protein beta-conglycinin was purified from the cotyledons of seedlings grown for 12 days. The enzyme was named protease C2 because it is the second enzyme to cleave the beta-conglycinin storage protein, the first (protease C1) being one that degrades only the alpha' and alpha subunits of the storage protein to products similar in size and sequence to the remaining intact beta subunit. Protease C2 activity is not evident in vivo until 4 days after imbibition of the seed. The 31 kDa enzyme is a cysteine protease with a pH optimum with beta-conglycinin as substrate of 5.5. The action of protease C2 on native beta-conglycinin produces a set of large fragments (52-46 kDa in size) and small fragments (29-25 kDa). This is consistent with cleavage of all beta-conglycinin subunits at the region linking their N- and C-domains. Protease C2 also cleaves phaseolin, the Phaseolus vulgaris vicilin homologous to beta-conglycinin, to fragments in the 25-28 kDa range. N-Terminal sequences of isolated beta-conglycinin and phaseolin products show that protease C2 cleaves at a bond within a very mobile surface loop connecting the two compact structural domains of each subunit. The protease C2 cleavage specificity appears to be dictated by the substrate's three-dimensional structure rather than a specificity for a particular amino acid or sequence. (+info)
Reactions of soybean peroxidase and hydrogen peroxide pH 2.4-12.0, and veratryl alcohol at pH 2.4.
(69/910)
Peroxidase from soybean seed coat (SBP) has properties that makes it particularly suited for practical applications. Therefore, it is essential to know its fundamental enzymatic properties. Stopped-flow techniques were used to investigate the pH dependence of the reaction of SBP and hydrogen peroxide. The reaction is linearly dependent on hydrogen peroxide concentration at acidic and neutral pH with the second order rate constant k(1)=2.0x10(7) M(-1) s(-1), pH 4-8. From pH 9.3 to 10.2 the reaction is biphasic, a novel observation for a peroxidase at alkaline pH. A fast reaction has the characteristics of the reaction at neutral pH, and a slow reaction shows hyperbolic dependence on hydrogen peroxide concentration. At pH >10.5 only the slow reaction is seen. The shift in mechanism is coincident with the change in haem iron co-ordination to a six-coordinate low spin hydroxy ligated alkaline form. The pK(a) value for the alkaline transition was observed at 9.7+/-0.1, 9.6+/-0.1 and 9.9+/-0.2 by spectrophotometric titration, the fast phase amplitude, and decrease in the apparent second order rate constant, respectively. An acidic pK(a) at 3.2+/-0.3 was also determined from the apparent second order rate constant. The reactions of soybean peroxidase compounds I and II with veratryl alcohol at pH 2.44 give very similar second order rate constants, k(2)=(2.5+/-0.1)x10(4) M(-1) s(-1) and k(3)=(2.2+/-0.1)x10(4) M(-1) s(-1), respectively, which is unusual. The electronic absorption spectra of compounds I, II and III at pH 7.07 show characteristic bands at 400 and 651 nm (compound I), 416, 527 and 555 nm (compound II), and 414, 541 and 576 nm (compound III). No additional intermediates were observed. (+info)
Feeding tolerance of ready-to-use versus powdered formulas in neonates.
(70/910)
BACKGROUND: Following the introduction of ready-to-use formula in our neonatal department, we observed an increase in the number of neonates regurgitating after feeding. OBJECTIVE: To compare the feeding tolerance of neonates, in terms of regurgitations, to ready-to-use versus powdered formulas. METHODS: We compared the number of regurgitations in 727 healthy neonates after feeding ready-to-use formulas and powdered formulas of two different manufacturers. Six groups of neonates were formed, three for each manufacturer. Each of the two groups was fed with either ready-to-use formula or with reconstructed powdered formula (using a two-compartment patented feeding bottle called Twist 'N Feed) and one group received both preparations during 2 successive days. RESULTS: The groups that were fed only with ready-to-use formulas had significantly more regurgitations than those fed with powdered formulas. Within the group that received both types of formulas there were significantly more regurgitations following the ready-to-use than the powdered formula. CONCLUSIONS: Feeding tolerance, in terms of regurgitations, was significantly better in neonates fed reconstituted powdered formula as opposed to ready-to-use formulas. More studies are required to determine the exact mechanism for these differences. (+info)
Expression and processing of a hormonally regulated beta-expansin from soybean.
(71/910)
Expansin proteins are essential components of acid-induced cell wall loosening in plants. Beta-expansins, which constitute a subfamily of related expansin proteins, include the group I grass pollen allergens. To provide a better description of beta-expansin expression, we have characterized a cytokinin-inducible beta-expansin from soybean (Glycine max cv Mandarin) called Cim1. Our results demonstrate that the hormones cytokinin and auxin act synergistically to induce the accumulation and proteolytic processing of Cim1. Carboxyl terminal truncation of a 35-kD form of Cim1 is predicted to remove the putative cellulose binding domain from the amino terminal cysteine-rich domain, resulting in a 20-kD form of the protein. Furthermore, the identical amino termini of the 35- and 20-kD forms of Cim1 correspond to a position 11 amino acids downstream of the predicted signal sequence cleavage site, suggesting proteolysis of a short amino terminal propeptide after removal of the signal peptide. This propeptide fragment contains a consensus site for N-glycosylation and our data suggest that it is glycosylated by a tunicamycin-sensitive mechanism in cultured soybean cells. The onset of Cim1 expression correlates with increased growth of soybean cultures. Ultimately, Cim1 is rapidly and specifically proteolyzed as soybean cultures reach stationary phase. These findings are consistent with the hypothesis that beta-expansin proteins are extensively modified by post-translational N-glycosylation and proteolysis. (+info)
Design and production of genetically modified soybean protein with anti-hypertensive activity by incorporating potent analogue of ovokinin(2-7).
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The potent anti-hypertensive peptide, RPLKPW, has been designed based on the structure of ovokinin(2-7). The sequence encoding this peptide was introduced into three homologous sites in the gene for soybean beta-conglycinin alpha' subunit. The native alpha' subunit as well as the modified, RPLKPW-containing alpha' subunit were expressed in Escherichia coli, recovered from the soluble fraction and then purified by ion-exchange chromatography. The RPLKPW peptide was released from recombinant RPLKPW-containing alpha' subunit after in vitro digestion by trypsin and chymotrypsin. Moreover, the undigested RPLKPW-containing alpha' subunit given orally at a dose of 10 mg/kg exerted an anti-hypertensive effect in spontaneously hypertensive rats, unlike the native alpha' subunit. These results provide evidence for the first time that a physiologically active peptide introduced into a food protein by site-directed mutagenesis could practically function in vivo even at a low dose. (+info)