Growth, cell viability and heat shock proteins (HSPs) in Bezostaya-1, Çukurova-86 and Diyarbakır-81 cultivated wheat cultivars and three Aegilops species were investigated. Etiolated seedlings were exposed to 23 °C, 32 °C, 35 °C, 37 °C and 38 °C for 24 h, and 35 °C (24 h) → 50 °C(1 h) and 37 °C (24 h) → (50 °C (1 h). At the end of recovery growth periods, the shoot lengths of the genotypes generally decreased significantly at 35, 37 and 38 °C. The acquired thermal tolerance (ATT) in intact seedlings was over 50% at 35 °C → 50 °C and 37 °C → 50 °C, but in cell viability test it ranged from 2.75% (Ae. triuncialis) to 32.87 (Bezostaya-1) at 35 °C, and from 2.82% (Ae. triuncialis) to 37.82 (Bezostaya-1) at 37 °C. Ae. triuncialis was most sensitive genotype in both ATT determination. In electrophoretic profiles of proteins, while some HSPs were newly synthesized, some normal cellular proteins disappeared at 37 °C and 37 °C → 50 °C compared to 23 °C. The number of low molecular weight (LMW) HSPs were more than intermediate- (IMW) and high- (HMW) HSPs. The genotypes had both common (12 HSPs between at least two genotypes) and genotype-specific (33 HSPs) LMW HSPs. The common HSP of 19.8 kDa (pI 6.5) was synthesized in Bezostaya-1, Çukurova-86, Diyarbakır-81, Ae. biuncialis and Ae. umbellulata. Bezostaya-1 is the only genotype that synthesized 12 IMW and 2 HMW HSPs at 37 °C → 50 °C. Ae. triuncialis had only two common LMW HSPs [22.1 (pI 7.1) and 24.2 kDa (pI 6.5)].
Authors:D. Horvat, V. Spanic, K. Dvojkovic, G. Simic, D. Magdic, and A. Nevistic
Under artificial Fusarium infection the total glutenin content determined by chromatographic (RP-HPLC) method was significantly reduced in comparison to gliadins which were increased. Among protein types, α-GLI and HMW-GS were the highest affected. Artificial Fusarium infection significantly increased GLI/GLU ratio when compared with the natural infected samples. Artificial Fusarium infection dramatically decreased the dough mixing tolerance and had a considerable negative effect on dough energy, maximum resistance, and resistance/extensibility ratio. Disturbed GLI/GLU ratio and an increased amount of mycotoxin DON under artificial Fusarium infection showed a strong negative impact on affected functional properties of dough and bread. Total and γ-GLI as well as GLI/GLU ratio were significantly positively affected by mycotoxin DON in contrast to total GLU, HMW-GS and LMW-GS which were negatively affected. Results indicated that the stability of baking quality parameters of cultivars more tolerance to the Fusarium infection can be well define by lower accumulation of mycotoxin DON.
Ultracentrifugation was used as a non-destructive method to separate dough into liquid, gel, gluten, starch and bottom phases. The protein composition in the different phases was investigated for dough prepared from spring wheat (Triticum aestivum L.). The SDS-PAGE, SE-HPLC and RP-HPLC methods were used for the analysis. The wheat protein composition of the liquid and gel phases consisted of albumins, globulins and traces of gliadins and glutenins. The gluten phase contained proteins extractable with all the extraction buffers used. A similar protein composition was found in the starch and bottom phases, but in considerably lower amounts. Specific LMW glutenin subunits were identified in the gluten phase by RP-HPLC. The albumin composition differed in the gel phase compared to the gluten and bottom phases. Differences in protein composition due to mixing methods were detected only for the albumin composition in the liquid phases.
Authors:D. Horvat, Z. Jurković, G. Drezner, G. Šimić, D. Novoselović, and K. Dvojković
The gluten proteins of 15 winter wheat cultivars grown in eastern Croatia were studied for their contribution to the bread-making quality. Composition of high-molecular-weight glutenin subunits (HMW-GS) was analyzed by SDS-PAGE, while the quantity of gluten proteins was determined by combined extraction/RP-HPLC procedure. The results of the linear correlation analysis carried out on the particular gluten proteins and technological properties showed that the amount of total gluten content highly correlates with protein content. Among gluten proteins, the glutenins showed higher correlation with protein content, with pronounced influence of HMW-GS, than gliadins. Wet gluten content was significantly correlated to total gliadin quantity. Gluten index as gluten quality parameter was positively influenced by total glutenins and low-molecular-weight glutenin subunits (LMW-GS), and negatively, by the ratios of gliadin to glutenin (Gli/Glu), whereas the amount of gliadins was not important. Dough development time was strongly correlated with total gluten content, total glutenins and the Gli/Glu ratio. Dough mixing resistance was strongly affected by total glutenin content with pronounced influence of HMW-GS. Degree of dough softening is mainly negative influenced by total glutenins and ratio of Gli/Glu. Farinograph quality number as flour quality index was highly positively correlated with total glutenins, with emphasized influence of HMW-GS. The Gli/Glu ratio had the highest influence on dough maximum resistance. Dough extensibility showed moderate correlation with total gliadins. The results of the linear correlation indicated that loaves volumes were significantly influenced by total gluten proteins, HMW-GS and LMW-GS.
Authors:I. Bellil, O. Hamdi, A. Benbelkacem, and D. Khelifi
Wheat endosperm storage proteins are the major components of gluten. They play an important role in dough properties and in bread making quality in various wheat varieties. In the present study, the different alleles encoded at the 5 glutenin loci were identified from a set of 38 tetraploid wheat germplasm obtained from interspecific crosses between durum wheats (Triticum turgidum L. ssp. durum (Desf.) Husn.) and their relatives (T. dicoccum Schübl. and T. polonicum L.) using SDS-PAGE. At Glu-A1 and Glu-B1, encoding high molecular weight glutenin subunits (HMW-GS), 2 and 4 alleles were observed, respectively. Low molecular weight glutenin subunits (LMW-GS) displayed similar polymorphism, as 3, 5 and 3 alleles were identified at loci Glu-A3, Glu-B3 and Glu-B2, respectively. One new allele was detected at Glu-B3 locus and appeared in nine accessions obtained from five crosses. This allele codes for five subunits (2 + 8 + 9 + 13 + 18), encoded by the Glu-B3b without subunit 16 plus subunits 2 and 18. A total of 38 patterns resulted from the genetic combination of the alleles encoding at the five glutenin loci. This led to a significantly higher Nei coefficient of genetic variation in Glu-1, Glu-3 and Glu-B2 loci (0.54). The germplasm analyzed exhibited allelic variation in HMW and LMW glutenin subunit composition and the variation differed from that of tetraploid wheats of other countries. The presence of high quality alleles in glutenin loci have led the accessions to be considered as an asset in breeding programs aimed for wheat quality.
The water soluble proteins of the lens collected from different age group of the fish Catla catla were subjected to Sephadex G 200 gel filtration to fractionate and to characterize the protein and further to determine the elution volume (Ve) of different fractions. The relative proportion of each fraction was also calculated. Total number of fractions F1 to F4 was discernible through gel filtration. The molecular weight of these varied from 35,000 Da to 640,000 Da. Three subfractions were also noted in F1 fraction. Interesting observations were, presence of a, bH, bL crystallins in all age groups and LMW proteins in older age group. a-crystallin present in major amounts in comparison to bH & bL crystallins. Decrease of a-crystallins (except in age group II) with the increase of age, counter balanced by the increase of bH crystallins. Increase of bH crystallins was followed by the decrease of bL crystallins. Results suggest that proportionate distribution of different classes of proteins determined by column chromatography is widely variable.
Authors:T. Abonyi, S. Tömösközi, M. Budai, Sz. Gergely, É. Scholz, D. Lásztity, and R. Lásztity
The proteins that form gluten of a winter wheat cultivar, Ukrainka (HMW-GS composition 1, 7+8, 5+10) grown in Hungary and harvested in the year 2006, was investigated during grain development. The formation of gluten, its protein fractions and composition of polymeric fraction, were followed starting at the 12
day after anthesis (DAA) to the 52
.Gluten formation was first observed (manual method of determination) only 20–25 days after anthesis and its quantity increased rapidly during the next period of grain development. The gluten was separated to a fraction extractable with SDS-phosphate buffer and another fraction, unextractable by this buffer. An increase in the ratio of unextractable polymeric protein (UPP)/soluble protein fraction was observed during grain development. As expected, gliadin was the main component of the soluble fraction and glutenin that of the insoluble one. HMW monomers were detected in unreduced fractions in small quantities only until 30
DAA. RP-HPLC of reduced gluten fractions showed a slight increase of the ratio HMW/LMW with days after anthesis.An increase of relative viscosity of gluten solutions during grain development was also observed as a sign of polymerization of glutenin subunits and consequently an increase in average molecular weight of glutenin.
Authors:Eva Mars, Péter Sipos, Árpád Tóth, and Zoltán Győri
Kohler et al.
(1993): Disulphide bonds in wheat gluten: further cystine peptides from high molecular weight (HMW) and low molecular weight (LMW) subunits of glutenin and from gamma-gliadins. Zeitschrift fur Lebensmittel Untersuchung and Forschung, 1993