scholarly journals Accumulation and changes in molecular size distribution of polymeric proteins in developing grains of hexaploid wheats: role of the desiccation phase

1999 ◽  
Vol 26 (4) ◽  
pp. 301 ◽  
Author(s):  
J. L. Carceller ◽  
T. Aussenac
Keyword(s):  
Molecular Weight ◽  
Size Distribution ◽  
High Molecular Weight ◽  
Molecular Size ◽  
Reversed Phase ◽  
Size Exclusion ◽  
Glutenin Subunits ◽  
Soluble Polymers ◽  
Molecular Size Distribution ◽  
Insoluble Polymers

Two varieties of wheat differing in high molecular weight glutenin subunit composition (Soissons, 5+10, Glu-D1a allele; Thésée, 2+12, Glu-D1a allele) were examined to follow the accumulation of polymeric proteins and the changes in molecular size distribution of these proteins during grain filling. The accumulation behaviour of polymeric proteins was determined by size-exclusion-HPLC, multistacking SDS-PAGE and the constituent polypeptides (high molecular weight and low molecular weight glutenin subunits) by reversed-phase-HPLC. For both cultivars, the accumulation of each class of protein was highly asynchronous, especially between the early deposition of SDS-soluble polymers and the late deposition of SDS-insoluble polymers, such that the average molecular size of polymeric protein increased in the period from 30 to 45 days after anthesis in natural conditions. By applying premature grain desiccations during the cell enlargement phase, it was demonstrated that the SDS-insoluble polymers formation was closely related with the process of water loss from the grain. Moreover, the rapid accumulation of SDS-insoluble polymers coincided with a rapid decrease in mass of both SDS-soluble polymers and monomers, suggesting an aggregative mechanism. Over the same period, the molecular size distribution of the polymers which can be used to differentiate the two genotypes studied, is highly correlated with the percentage of high molecular weight glutenin subunits in glutenins present in kernels when desiccation occurred. The formation of SDS-insoluble fraction is discussed in connection with the specific contribution of high molecular weight glutenin subunits to the formation of polymers (subunits linked by disulfide bonds).

The effect of different oxidation and filtration processes on the molecular size distribution of humic material

1994 ◽  
Vol 30 (9) ◽  
pp. 169-174 ◽  
Author(s):  
T. Kainulainen ◽  
T. Tuhkanen ◽  
T. Vartiainen ◽  
H. Heinonen-Tanski ◽  
P. Kalliokoski
Keyword(s):  
Molecular Weight ◽  
Lake Water ◽  
Molecular Size ◽  
Size Exclusion ◽  
Humic Material ◽  
H2o2 Treatment ◽  
The Third ◽  
Exclusion Chromatography ◽  
Molecular Size Distribution ◽  
Humic Fractions

The effect of different oxidation and filtration processes on the amount and character of organic matter in drinking water was studied. TOC, KMnO4 value, colour and fractions of humic material were analyzed from bank filtrated lake water, chemically coagulated and sand filtrated water, ozonated, O3/H2O2 treated, chlorinated, granular activated carbon (GAC) filtrated and nanofiltrated water. Size exclusion chromatography was used to separate different fractions of humic molecules. Six different fractions were found from bank filtrated lake water and from chemically coagulated and sand filtrated water. The molecular weight of humic fractions ranged from about 1000 (the last fraction) to about 100 000 dalton (the first fraction). Most of the humic molecules of bank filtrated lake water were found in the third and fourth fractions. After the oxidation and filtration processes the first fraction of humic molecules disappeared completely and the fourth and fifth fractions dominated. The total sum of the humic fractions was most effectively reduced after the O3/H2O2 treatment, by about 70%.

Phosphorus affects high-molecular-weight glutenin subunits and glutenin macropolymer size distribution in wheat grains

2013 ◽  
Vol 152 (5) ◽  
pp. 759-769 ◽  
Author(s):  
Y. NI ◽  
D. YANG ◽  
Z. WANG ◽  
Y. YIN ◽  
T. CAI ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Size Distribution ◽  
High Molecular Weight ◽  
Application Rate ◽  
Utilization Efficiency ◽  
Glutenin Subunits ◽  
Particle Volume ◽  
Wheat Grains ◽  
P Application ◽  
Glutenin Macropolymer

SUMMARYTwo winter wheat (Triticum aestivum L.) cultivars, Jimai20 and Shannong12, differing in phosphorus (P) utilization efficiency, were selected to study the effect of P application rate on changes in glutenin macropolymer (GMP) size distribution and the content of high-molecular-weight glutenin subunits (HMW-GS) in wheat grain. Four P levels (0, 40, 100 and 160 kg/ha) were applied under N1 (112·5 kg/ha) and N2 (225 kg/ha) conditions in the field, in 2008/09 and 2009/10. The results showed that increased P levels favoured HMW-GS synthesis under N1 conditions, but had a less pronounced effect under N2. When compared with the control, the volume proportions of <10 μm GMP particles in grains of both cultivars were significantly decreased, and those of >100 μm were increased in response to P application. The volume proportions of 10–100 μm GMP particles in the cultivars Jimai20 and Shannong12 were respectively lower and higher in response to P application than with no P fertilizer. At maturity, for both cultivars, total HMW-GS content was negatively correlated with GMP particle volume of <10 μm, but positively correlated with that of >100 μm. These observations suggest that both P and N affect protein synthesis in wheat grains and there exists a relationship between HMW-GS content and the synthesis of large GMP particles (>100 μm). The N×P interaction was the most important factor to regulate the HMW-GS and GMP contents.

SDS-insoluble glutenin polymer formation in developing grains of hexaploid wheat: the role of the ratio of high to low molecular weight glutenin subunits and drying rate during ripening

2001 ◽  
Vol 28 (3) ◽  
pp. 193 ◽  
Author(s):  
Jean-Luc Carceller ◽  
Thierry Aussenac
Keyword(s):  
Molecular Weight ◽  
Accumulation Rate ◽  
Protein Biosynthesis ◽  
Relative Proportion ◽  
Reversed Phase ◽  
Low Molecular Weight ◽  
Separation Procedure ◽  
Glutenin Subunits ◽  
Desiccation Rate ◽  
Insoluble Polymers

The accumulation of polymeric proteins and the changes in molecular size distribution of these proteins were followed during grain filling and/or premature desiccation. The accumulation behavior of polymeric proteins and their constituent polypeptides (high and low molecular weight glutenin subunits, HMW-GS and LMW-GS) was determined by reversed phase-high performance liquid chromatography using a NaI/propanol purification procedure. With this new extraction and separation procedure, we have demonstrated that there was a coordinated initiation of storage protein biosynthesis, even if the accumulation rate varied greatly between the two main classes of proteins (i.e. monomeric and polymeric fractions). Moreover, the glutenin subunit composition was largely modified during glutenin accumulation. Both the HMW-GS/LMW-GS and HMW-GS-x/HMW-GS-y ratios increased significantly during the whole cell enlargement phase (from 16 to 37 d after anthesis). By applying premature grain desiccation during this physiological phase, we demonstrated that the polymerization index (SDS-insoluble polymers/total polymers) of the glutenin polymers was closely related to the HMW-GS/LMW-GS ratio of these proteins. An increase in the relative proportion of HMW-GS in glutenins caused the proportion of SDS-insoluble polymers to rise during grain desiccation. From these studies, it appears that the modification of the desiccation rate (grain desiccation at a constant temperature with variable relative humidity levels) induced a parallel modification of the glutenin insolubilization rate but did not affect the polymerization index of the glutenins at maturity.

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