Proteins In Sorghum Research Articles

A sorghum 85 kDa heat stress-modulated protein shows calmodulin-binding properties and cross-reactivity to anti- Neurospora crassa Hsp 80 antibodies

The present study, carried out to identify stress-modulated calmodulin (CaM)-binding proteins in sorghum, resulted in the isolation of several proteins, which showed binding to CaM-Sepharose matrix. Calmodulin gel overlay assay and MALDI-ToF MS analysis revealed that an 85 kDa protein (Hsp85), which interacted with calmodulin, cross-reacted with anti- N. crassa Hsp80 antibodies. Since these antibodies bind to plant Hsp90, sorghum Hsp85 is likely to be a member of the Hsp90 family. This study provides the first evidence that a member of Hsp90 (Hsp85) in plants exhibits CaM-binding properties.

The content of proteic and nonproteic (free and protein-bound) tryptophan in quinoa and cereal flours

The content of proteic and nonproteic (free and protein-bound) tryptophan and of proteins in quinoa, wheat, rice, maize, barley, oat, rye, spelt, sorghum and millet flours was determined. Protein content and proteic tryptophan of quinoa were similar to that of wheat and spelt, but higher than in other cereals. Free tryptophan in quinoa flour showed values similar to those of wheat, oat and sorghum Kalblank, lower than those of barley, spelt and pearl millet, but higher than in rice, maize, rye, sorghum DK 34 – Alabama hybrid. In addition, nonproteic tryptophan appears bound both to water soluble proteins and to proteins soluble at pH 8.9. The results are discussed regarding the importance of the nonprotein tryptophan fraction, the only one able to enter the brain, that is more easily absorbed, so guarantees a greater amount available for uptake by the central nervous system.

Purification and distribution of pathotoxin-enhanced proteins in sorghum

The synthesis of a group of four 16 kDa proteins in sorghum [ Sorghum bicolor (L.) Moench] roots is enhanced by treatment with peritoxin, the host-selective toxin produced by the root rot fungus Periconia circinata (Mangin) Sacc. The proteins were purified by two-dimensional gel electrophoresis and partially characterized, and their distribution within the sorghum plant and in other plant species was determined. The four proteins were found to be charge isomers indistinguishable by electrophoretic analysis of the products of protease digestion and CNBr cleavage. In Western blots with polyclonal antibodies, the proteins were detected in all organs of mature sorghum plants in quantities that decreased from the roots upward toward the inflorescence. Multiple cross-reacting proteins from 15–21 kDa were also detected in all grass species tested and in some other monocotyledons. None of the dicotyledons analysed contained cross-reacting proteins. The results suggest that the 16 kDa proteins are conserved proteins whose constitutive synthesis is regulated and whose function is important in several plant species, especially grasses. The presence of these proteins in other plant species suggests that they are not the direct cause of disease symptoms and plant cell death in peritoxin-treated sorghum plants.

Characterisation of chloroplast heat shock proteins in young leaves of C4 monocotyledons

In vivo radiolabeling of chloroplast proteins in grain sorghum (Sorghum bicolor L. cv. Texas 610) leaves and their separation by one‐dimensional electrophoresis revealed at least 6 heat shock proteins (HSPs) between 24 and 94 kDa. of which the 24 kDa protein was the most prominent. All of these chloroplast heat shock proteins were found exclusively in the stroma. The 24 kDa heat shock protein, upon closer examination using two‐dimensional electrophoresis proved to be two similarly‐sized heat shock polypeptides with identical molecular masses and level of radiolahel incorporation, hut slightly different in isoeiectric points, suggesting isomers. Separation of stromal heat shock proteins synthesised in two other C4 monocotyledons (Punicum miliaceum L. and Umchloa panictrides L.) revealed similar putative isomers. each of 24 kDa. Several other, previously unidentified, heat shock proteins between 22 and 38 kDa were also observed in all three species. In P. miliaceum. the most prominent HSP was the pair of 24 kDa proteins, whereas in U. panicoides. it was a group of 35 to 38 kDa HSPs that was most abundant. In vivo chlorophyll fluorescence measurements showed that no sustained impairment to photosynthetic efficiency had occurred for each species after the heat stress regime. However, when cytoplasmic protein synthesis was inhibited during the high temperature treatment, a dramatic decrease was observed in photosynthetic efficiency, suggesting a possible protective role for chloroplast heat shock proteins. It was also shown that a single chloroplast HSP complex of around 380 kDa was observed in the stroma of both 5. bicolor and P. miliaceum leaves in vivo. This was in contrast to the smaller HSP complex (200–265 kDa) observed in previous studies on chloroplast heat shock proteins in Cj species.

Relationships between Grain Hardness and the Contents of Prolamin and Three Anti-fungal Proteins in Sorghum

Abstract The contents of three anti-fungal proteins of Mr 18k, 26k and 30k were determined by enzyme-linked immunosorbent assay (ELISA) for 40 cultivars of sorghum that varied in grain hardness and prolamin content. Statistically significant relationships were observed between the contents of the anti-fungal proteins and prolamin content, particularly for the Mr 18k (r=0·64) and 30k (r=0·73) proteins. Analysis of hard and soft portions of two cultivars shared that the Mr 18, 26 and 30k proteins were present at a higher level in the corneous endosperm than in the floury endosperm. Immunofluorescence microscopy, using antisera raised in rabbits against these proteins, revealed that the anti-Mr 18k antiserum reacted primarily with the protein bodies and along the cell walls, where the protein bodies are concentrated. Labelling was also more intense in the outer than in the inner endosperm. The Mr 26k protein was associated primarily with the cell walls and not with the protein bodies. The peripheral endosperm was labelled to the greatest extent as detached by immunofluorescence. No fluorescence was observed for the Mr 30k protein. The results indicate a locational and quantitative link between the sorghum prolamins and anti-fungal proteins. This may be due to common genetic modulation or linkage.

Effect of Extrusion Cooking on the Nutritive Value of Proteins in Grain Sorghum.

Galgal (Citrus pseudolimon Tan.) juice concentrates of various degrees Brix (45°, 60° and 70.5°B) were prepared using rotary type vacuum evaporator (55 ′ 2°C and 28 ′ 2 * Hg vacuum). Storage studies on these products indicated that all concentrates stored up to six months experienced slight increase in total solids (2.27 %), reducing sugars (1.22 % dwb), hydroxymethyl furfural (16.75 times) and non-enzymatic browning (3 times) and a consistent decline in ascorbic acid (50.29 % dwb). However, the changes in physico-chemical and sensory qualities were comparatively less in concentrates stored under refrigerated conditions (3-7°C) than those stored at room temperature (13.3 - 26.3°C). Further, the retention of quality attributes during storage was better in juice concentrate of 45°B than the concentrates of higher folds.

Heat Shock Proteins in Sorghum and Pearl Millet; Ethanol, Sodium Arsenite, Sodium Malonate and the Development of Thermotolerance

Treatment of sorghum (Sorghum bicolor L. Moench) seedlings with arsenite or malonate at normal growing temperatures (35 °C) resulted in restricted synthesis of heat shock proteins (HSPs) without affecting 'normal' protein synthesis. In millet (Pennisetum glaucum (L.) R.Br.) seedlings, little alteration in the pattern of proteins synthesized was detected in the presence of these compounds. Ethanol greatly reduced in vivo protein synthesis in both species. Incubation with arsenite and malonate resulted in an increase in thermotolerance of both sorghum and millet seedlings. Additionally, HSPs were synthesized at an otherwise injurious high temperature if a pretreatment with arsenite or malonate was given. Extraction of RNA from arsenite-treated seedlings indicated that translatable RNAs encoding HSPs are present in both sorghum and millet seedlings at 35 °C and it is possible that they are not translated in vivo until an increase of temperature is also perceived by the seedling. Thus, treatment with arsenite results in both the transcription of genes encoding HSPs and in the development of thermotolerance. This provides further evidence for the involvement of HSPs, or the mRNA encoding these proteins, in thermotolerance.

EFFECT OF SODIUM LAURYL SULFATE IN SOLUBILIZING PROTEIN FOR TRYPTOPHAN DETERMINATION

The solubilization of proteins in corn and sorghum, using sodium lauryl sulfate (NaLS) in a basic medium, was used for tryptophan determination. The experimental design evaluated different levels of sodium lauryl sulfate and sodium hydroxide, at various temperatures and times. Prior to treatment, the samples were dried, ground and defatted. These were hydrolyzed and tryptophan was quantified spectrophotometrically (λmax= 565 nm). Casein was used as control and DL-tryptophan was used for generating the standard curve according to Beer's Law. From the results obtained, it was possible to conclude that sodium lauryl sulfate was very effective in solubilizing corn and sorghum protein for subsequent tryptophan determination.

Improving the in vitro protein digestibility of sorghum with reducing agents

We have shown in previous reports that cooked sorghum protein is less digestible than other cooked cereal proteins. The pepsin-indigestible proteins in sorghum were found to be mainly prolamin proteins. Cooking sorghum in the presence of 2-mercaptoethanol increased protein digestibility (in vitro with pepsin or trypsin/chymotrypsin) to a level comparable with other cereals. At a concentration of 100 mM, other reducing agents (dithiothreitol, sodium bisulfite, and L-cysteine) were equally effective in improving sorghum digestibility. When maize was cooked in the presence of 2-mercaptoethanol, protein digestibility increased 5% compared to 25% for sorghum. Cooking barley, rice, and wheat with 2-mercaptoethanol had no significant effect on protein digestibility. The addition of reducing agents appears to prevent the formation of protein polymers linked by disulfide bonds.

Pepsin digestibility of proteins in sorghum and other major cereals

We have shown previously that sorghum is highly digestible in the rat. However, other workers have shown that sorghum is much less digestible than wheat, maize, and rice in young children. Because the rat does not show these digestibility differences, we developed an empirical pepsin digestion method, first reported in 1981, which simulates the digestion values found in children. In this report the method has been improved and used to analyze wheat, maize, rice, millet, and sorghum and certain processed samples of millet and sorghum. The pepsin digestion values parallel those found in children for wheat, maize, rice, and sorghum. In addition, a processed sorghum product that gave a high digestion value in children also gave a high value with the in vitro pepsin method.

Effect of Incremental Dosages of the Waxy Gene of Sorghum on Digestibility

The effect of degree of the waxy characteristic of sorghum on in vitro and in situ digestibility was determined. Crosses were made within two pairs of sorghum cuftivars to produce grain with following genotypes: non-waxy (WxWxWx); intermediate waxy (WxWxwx and Wxwxwx); and waxy (wxwxwx). Grains were harvested at physiological maturity and processed to yield ground grain and purified starch. Amylose content decreased with incremental increases of the waxy gene, but two doses were required to significantly reduce the percent amylose. The homozygous waxy grains had only traces of amylose. Incremental increases of the waxy gene increased both in vitro and in situ digestibility. Ruminal digestibility, as measured by nutrient disappearance or by gas production, was significantly greater in the homozygous waxy grain than other genotypes. Partial hydrolysis of the proteins in sorghum by pronase increased in vitro digestibility in all genotypes. Digestibility of pronase treated ground grain approached that of purified starch. Solubilization of the proteins in sorghum was affected by genotype with proteins in the homozygous waxy grain being more soluble (P<.05) than the homozygous non-waxy proteins.

Nutritional quality of proteins in grain sorghum

Grain sorghum is low in protein content Lysine, threonine and tryptophan are the limiting amino acids in the proteins of grain Sorghum. Protein fractionation studies have shown that prolamine and glutelin are the principal protein fractions. Increase in protein content of grain Sorghum leads to an increase in prolamin fraction and decreases the nutritional quality. Environmental factors such as location, chemical fertilizers, plant population and chemical treatments influence the protein content and amino acid pattern. The presence of tannins in grain Sorghum reduces the digestibility and nutritional quality.

THE NUTRITIONAL QUALITY OF PROTEINS IN SORGHUM

ABSTRACTPhase one of a twephase project identified lysine and threonine as the first and second limiting amino acids of sorghum in rats. Supplementation of L‐lysine. HCl at the 0.4% level to sorghum diets fed to rats at the 10% protein level (N ± 6.25) resulted in increased weight gain; the addition of threonine caused further gain. No improvement in weight gains of rats was noted when methionine, tryptophan or isoleucine was added. In Phase two, when the proteins in sorghum were compared with those in corn or wheat as the sole source of dietary protein at the 8.0% crude protein level, nutritional values of the proteins were found to be similar. With soybean oil meal supplementation and fed at the 8.0% crude protein level, no significant differences in nutritive value of any of the diets were noted The biological value of the proteins in sorghum can be improved by supplementation with selected amino acids and by combining with other food sources.

Relationship between tannin levels, rat growth, and distribution of proteins in sorghum.

Three high tannin varieties of sorghum gave significantly lower growth responses in weaning rats when compared with three low tanning varieties. Whole kernel and hand-separated endosperms were fractionated by the Landry and Moureaux method to yield five soluble fractions...