Proteomics reveals commitment to germination in barley seeds is marked by loss of stress response proteins and mobilisation of nutrient reservoirs

Germination is a critical process in the reproduction and propagation of flowering plants, and is also the key stage of industrial grain malting. Germination commences when seeds are steeped in water, followed by degradation of the endosperm cell walls, enzymatic digestion of starch and proteins to provide nutrients for the growing plant, and emergence of the radicle from the seed. Dormancy is a state where seeds fail to germinate upon steeping, but which prevents inappropriate premature germination of the seeds before harvest from the field. This can result in inefficiencies in industrial malting. We used Sequential Window Acquisition of all THeoretical ions Mass Spectrometry (SWATH-MS) proteomics to measure changes in the barley seed proteome throughout germination. We found a large number of proteins involved in desiccation tolerance and germination inhibition rapidly decreased in abundance after imbibition. This was followed by a decrease in proteins involved in lipid, protein and nutrient reservoir storage, consistent with induction and activation of systems for nutrient mobilisation to provide nutrients to the growing embryo. Dormant seeds that failed to germinate showed substantial biochemical activity distinct from that of seeds undergoing germination, with differences in sulfur metabolic enzymes, endogenous alpha-amylase/trypsin inhibitors, and histone proteins. We verified our findings with analysis of germinating barley seeds from two commercial malting facilities, demonstrating that key features of the dynamic proteome of germinating barley seeds were conserved between laboratory and industrial scales. The results provide a more detailed understanding of the changes in the barley proteome during germination and give possible target proteins for testing or to inform selective breeding to enhance germination or control dormancy. SIGNIFICANCE: Germination is critical to the reproduction and propagation of flowering plants, and in industrial malting. Dormancy, where seeds fail to germinate upon steeping, can result in inefficiencies in industrial malting. Our DIA/SWATH-MS proteomics analyses identified key changes during germination, including an initial loss of proteins involved in desiccation tolerance and germination inhibition, followed by decreases in lipid, protein and nutrient reservoir storage. These changes were consistent between laboratory and industrial malting scales, and therefore demonstrate the utility of laboratory-scale barley germination as a model system for industrial malt house processes. We also showed that dormant seeds that failed to germinate showed substantial biochemical activity distinct from that of seeds undergoing germination, consistent with dormancy being an actively regulated state. Our results provide a more detailed understanding of the changes in the barley proteome during germination and give possible target proteins for testing or to inform selective breeding to enhance germination or control dormancy.

Water droplet surface tension method - An innovation in quantifying saponin content in quinoa seed

Quinoa surface borne saponins are bitter tasting anti-nutritional compounds that must be removed before consumption of the seed. To determine saponin content, the currently available standard afrosimetric foam test method only determines the presence of saponin via a rating of either 'acceptable' or 'unacceptable'. A water droplet surface tension (WDST) based innovative method was developed that can quantify saponin content in aqueous solutions with greater accuracy. The method comprised four steps: solution preparation, droplet creation, image capture and image analysis using Axisymmetric Drop Shape Analysis computer software. The method applied satisfactorily to saponin content up to 0.2 mg.ml^-1 as higher concentrations did not further reduce the surface tension. Results demonstrated that saponin concentration may be measured in the range 0.05 to 0.15 mg.ml^-1 (0.05 - 0.15% saponin by weight of seed). Validation of the WDST method on commercial and experimental samples offers quinoa processors an accurate inexpensive way of measuring saponin concentration to satisfy current seed quality specifications.

Effect of sorghum flour addition on in vitro starch digestibility, cooking quality, and consumer acceptability of durum wheat pasta

Whole grain sorghum is a valuable source of resistant starch and polyphenolic antioxidants and its addition into staple food like pasta may reduce the starch digestibility. However, incorporating nondurum wheat materials into pasta provides a challenge in terms of maintaining cooking quality and consumer acceptability. Pasta was prepared from 100% durum wheat semolina (DWS) as control or by replacing DWS with either wholegrain red sorghum flour (RSF) or white sorghum flour (WSF) each at 20%, 30%, and 40% incorporation levels, following a laboratory-scale procedure. Pasta samples were evaluated for proximate composition, in vitro starch digestibility, cooking quality, and consumer acceptability. The addition of both RSF and WSF lowered the extent of in vitro starch digestion at all substitution levels compared to the control pasta. The rapidly digestible starch was lowered in all the sorghum-containing pastas compared to the control pasta. Neither RSF or WSF addition affected the pasta quality attributes (water absorption, swelling index, dry matter, adhesiveness, cohesiveness, and springiness), except color and hardness which were negatively affected. Consumer sensory results indicated that pasta samples containing 20% and 30% RSF or WSF had acceptable palatability based on meeting one or both of the preset acceptability criteria. It is concluded that the addition of wholegrain sorghum flour to pasta at 30% incorporation level is possible to reduce starch digestibility, while maintaining adequate cooking quality and consumer acceptability.

Reversible airway obstruction in rheumatic mitral valve disease

Lung function was studied in 24 patients with advanced mitral stenosis scheduled for mitral valve replacement (MVR), and revealed an obstructive ventilatory pattern. Forty per cent of the patients had a forced expiratory volume in 1 s (FEV1)<60% of that predicted in the preoperative period. Twenty-five per cent of those operated upon showed a similar pattern up to 110 weeks postoperatively. A blind study of the effect of placebo and beta2 agonist (salbutamol) inhalation was performed preoperatively and 6 months postoperatively, to evaluate the reversibility of airflow obstruction in these patients, flow volume curve and body plethysmographic measurement of airway resistance (Rex) and intrathoracic gas volume (VTG). Patients in the pre and postoperative period showed a significant difference between the placebo and the beta2 agonist responses for FEV1, FEV1 as percentage of FVC (FEV1% FVC), peak expiratory flow rate (PEFR), flow rate of 50% of expiratory vital capacity (Vmax50), Rex and VTG (P<0.001). We conclude that salbutamol inhalation improves obstructive impairment in patients with MVR pre- and postoperatively.

DNA segregation in Escherichia coli cells with 5-bromodeoxyuridine-substituted nucleoids

The pattern of segregation of DNA in Escherichia coli K-12 was analyzed by labeling replicating DNA with 5-bromodeoxyuridine followed by differential staining of nucleoids. Three types of visible arrangement were found in four-nucleoid groups derived from a native nucleoid after two replication rounds. Type A, segregation of both old strands toward cell poles, appeared with the highest frequency (0.6 to 0.8). Type B, segregation of one old strand toward the cell pole and the other toward the cell center, was twice as frequent as type C, segregation of both old strands toward the cell center. These results confirm previous data showing that DNA segregation in E. coli is nonrandom while presenting a certain degree of randomness. The proportions of the three indicated types of arrangement suggest a new probabilistic model to explain the observed segregation pattern. It is proposed that DNA strands segregate either nonrandomly, with a probability of between 0 and 1, or randomly. In nonrandom segregation, both old strands are always directed toward cell poles. Experimental data reported here or by other authors fit better with the predictions of this model than with those of other previously proposed proposed deterministic or probabilistic models.