Depolymerization of the Glutenin Macropolymer During Mixing: II. Differences in Retention of Specific Glutenin Subunits

The depolymerization of individual high and low molecular weight (HMW and LMW, respectively) glutenin subunits (GS) from the glutenin macropolymer (GMP) in doughs during mixing was investigated by reversed-phase (RP) HPLC and SDS-PAGE. Cultivars with different dough strengths, as well as lines null for specific HMW-GS and biotypes differing at individual HMW-GS and LMW-GS encoding loci, were studied. During mixing, the proportion of total HMW-GS in GMP decreased, and the ratios of different subunits in the GMP in doughs changed. There was a loss of chromosome 1B- and 1D-encoded x-HMW-GS, while the relative proportions of y-HMW-GS (among HMW-GS) increased. Changes in 1B subunits occurred first, while most of the changes in 1D HMW-GS content occurred during dough breakdown. Changes were more pronounced for doughs of weak to average strengths than for stronger doughs. RP-HPLC analysis demonstrated a consistent increase in the retention times (surface hydrophobicity) of chromosome 1D-encoded HMW-GS but not of other HMW-GS or LMW-GS during mixing. SDS-PAGE and RP-HPLC demonstrated that specific B subunits, typically those with lower hydrophobicity, were selectively depolymerized from the GMP during dough breakdown, while the proportions of specific C subunits, typically those with greater hydrophobicity, increased. Similar trends were seen in analyses of several pairs of biotypes differing at single LMW-GS encoding loci, although there were slight differences in the depolymerization behavior of wheats with different allelic compositions. The results suggest that dough breakdown may be triggered by the loss of specific HMW-GS from the GMP, and a structural hierarchy may exist for different LMW-GS within glutenin in doughs.     

Effects of perfluoroalkyl substances (PFASs) and benzo[a]pyrene (BaP) co-exposure on phase I biotransformation in rainbow trout (Oncorhynchus mykiss)

Fish Physiology and Biochemistry - The presence of perfluoroalkyl substances (PFASs) in the environment, especially in aquatic ecosystems, continues to be a significant concern for human and...     

模拟自然光周期下外源性CO2对城市污水 藻类生长和污水处理的影响（摘选）

探讨了不同光照强度和模拟自然光周期条件下,高浓度生物污水中外源CO2对小球藻(Chlorella kessleri)生物量累积和污水中养分去除的影响。研究结果表明,在所有光强处理情况下,模拟光周期和施加CO2使得Chlorella kessleri能容易地适应反应器中的废水浓度。CO2浓度和光强显著影响藻类生长和污水中养分去除。藻类生长的最适CO2浓度是2.5%。当光强达到一定的下限时,由于光合自养效率显著减少,因此补充CO2的效果最小。同时,由于在第8天时养分耗尽和藻类生物累积量减少,对于持续或分批培养系统的应用体系,应优先选择分批培养的方式。关键词:藻类;城市污水;外源CO2;光照强度;生物量积累;废水处理