Determination of carbohydrate accumulation and plant growth dynamics in snowdrop (Galanthus elwesii Hook.) response to moisture levels in different substrates

In terms of botany, geophytes are known by their own survival strategy due to have a swollen storage organs. Snowdrops (Galanthus, 20 spp.; Amaryllidaceae) are important type of wild-sourced ornamental bulb genus in all geophyte species. Also, have a great deal of potential for use on landscape designs. Whereas, not much study has been done regarding the growth dynamics of snowdrops at harsh environmental conditions. This experiment was conducted to evaluate the effects of abiotic stress conditions on the performance of snowdrop (Galanthus elwesii Hook.) in soiless culture. Substrates and moisture were the variables. Peat + perlite and cocopeat were used as a substrate in pots. Moisture levels were applied; ML1, ML2 (well-watered and moderately tolerant treatments), ML3 (moderate stress) and ML4 (severe stress). Moisture had a statistically significant effect (P < 0.05) on circumference size, height and weight of the snowdrop bulbs. Plant height and carbohydrate accumulation were also affected by moisture levels in different substrates. The correlation between total carbohydrate (r = 0.95) and starch (r = 0.98) were positively determined. The reduced sugar, total sugar, starch and total carbohydrate values were increased by the severe stress treatment (ML4).

Growth, carbohydrate accumulation, and productivity of local glutinous corn Bimapulut (Zea mays var. ceratina Kuleshov) after seed priming and coconut coir ash fertilizer application

Seed priming and applying organic K fertilizer can involve efforts to increase local glutinous corn Bimapulut productivity. This study aims to determine the effect of gibberellin (GA3) as seed priming and coconut coir ash fertilizer on the growth, carbohydrate accumulation, and productivity of Bimapulut corn. The research was conducted using a randomized block design. The main plot was seed priming treatment with gibberellin concentrations of 0, 150, and 300 ppm. As a subplot was the treatment of coconut coir ash fertilizer with fertilizer/soil concentration of 0.00; 0.75; 1.50; 3.00 g/kg; thus, there are 12 treatment combinations. Each treatment was done in three replications. Data were analyzed using separate plot ANOVA with treatment arranged in a factorial. If the treatment is significant, Tukey’s honestly significant difference test will be carried out. The results an interaction between GA3 and coconut coir ash fertilizer on plant height, productivity without corn husks kg/ha, and amylose content but had no significant effect on leaf number, number of cobs per plant, cob length, number of row of seeds per cob, the weight of cob with and without corn husks.

Monod model is insufficient to explain biomass growth in nitrogen-limited yeast fermentation

The yeast Saccharomyces cerevisiae is an essential microorganism in food biotechnology; particularly, in wine and beer making. During wine fermentation, yeasts transform sugars present in the grape juice into ethanol and carbon dioxide. The process occurs in batch conditions and is, for the most part, an anaerobic process. Previous studies linked limited-nitrogen conditions with problematic fermentations, with negative consequences for the performance of the process and the quality of the final product. It is, therefore, of the highest interest to anticipate such problems through mathematical models. Here we propose a model to explain fermentations under nitrogen-limited anaerobic conditions. We separated the biomass formation into two phases: growth and carbohydrate accumulation. Growth was modelled using the well-known Monod equation while carbohydrate accumulation was modelled by an empirical function, analogous to a proportional controller activated by the limitation of available nitrogen. We also proposed to formulate the fermentation rate as a function of the total protein content when relevant data are available. The final model was used to successfully explain experiments taken from the literature, performed under normal and nitrogen-limited conditions. Our results revealed that Monod model is insufficient to explain biomass formation kinetics in nitrogen-limited fermentations of S. cerevisiae . The goodness-of-fit of the herewith proposed model is superior to that of previously published models, offering the means to predict, and thus control fermentations. Importance: Problematic fermentations still occur in the winemaking industrial practise. Problems include sluggish rates of fermentation, which have been linked to insufficient levels of assimilable nitrogen. Data and relevant models can help anticipate poor fermentation performance. In this work, we proposed a model to predict biomass growth and fermentation rate under nitrogen-limited conditions and tested its performance with previously published experimental data. Our results show that the well-known Monod equation does not suffice to explain biomass formation.

Monod model is insufficient to explain biomass growth in nitrogen-limited yeast fermentation

The yeast Saccharomyces cerevisiae is an essential microorganism in food biotechnology; particularly, in wine and beer making. During wine fermentation, yeasts transform sugars present in the grape juice into ethanol and carbon dioxide. The process occurs in batch conditions and is, for the most part, an anaerobic process. Previous studies linked limited-nitrogen conditions with problematic fermentations, with negative consequences for the performance of the process and the quality of the final product. It is, therefore, of the highest interest to anticipate such problems through mathematical models. Here we propose a model to explain fermentations under nitrogen-limited anaerobic conditions. We separated the biomass formation into two phases: growth and carbohydrate accumulation. Growth was modelled using the well-known Monod equation while carbohydrate accumulation was modelled by an empirical function, analogous to a proportional controller activated by the limitation of available nitrogen. We also proposed to formulate the fermentation rate as a function of the total protein content when relevant data are available. The final model was used to successfully explain experiments taken from the literature, performed under normal and nitrogen-limited conditions. Our results revealed that Monod model is insufficient to explain biomass formation kinetics in nitrogen-limited fermentations of S. cerevisiae. The goodness-of-fit of the herewith proposed model is superior to that of previously published models, offering the means to predict, and thus control fermentations.

Elevated Trehalose Levels in C. elegans daf-2 Mutants Increase Stress Resistance, Not Lifespan

The C. elegans insulin/IGF-1 (insulin-like growth factor 1) signaling mutant daf-2 recapitulates the dauer metabolic signature—a shift towards lipid and carbohydrate accumulation—which may be linked to its longevity and stress resistance phenotypes. Trehalose, a disaccharide of glucose, is highly upregulated in daf‑2 mutants and it has been linked to proteome stabilization and protection against heat, cold, desiccation, and hypoxia. Earlier studies suggested that elevated trehalose levels can explain up to 43% of the lifespan extension observed in daf-2 mutants. Here we demonstrate that trehalose accumulation is responsible for increased osmotolerance, and to some degree thermotolerance, rather than longevity in daf-2 mutants. This indicates that particular stress resistance phenotypes can be uncoupled from longevity.

Monod law is insufficient to explain biomass growth in nitrogen-limited yeast fermentation

ABSTRACTThe yeast Saccharomyces cerevisiae is an essential microorganism in food biotechnology; particularly, in wine and beer making. During wine fermentation, yeasts transform sugars present in the grape juice into ethanol and carbon dioxide. The process occurs in batch conditions and is, for the most part, an anaerobic process. Previous studies linked limited-nitrogen conditions with problematic fermentations, with negative consequences for the performance of the process and the quality of the final product. It is, therefore, of the highest interest to anticipate such problems through mathematical models. Here we propose a model to explain problematic fermentations under nitrogen-limited anaerobic conditions. We separated the biomass formation into two phases: growth and carbohydrate accumulation. Growth was modelled using the well-known Monod law while carbohydrate accumulation was modelled by an empirical function, analogous to a proportional controller activated by the limitation of available nitrogen. We also proposed to formulate the fermentation rate as a function of the total protein content when relevant data are available. The final model was used to successfully explain a series of experiments taken from the literature, performed under normal and nitrogen-limited conditions. Our results revealed that Monod law is insufficient to explain biomass formation kinetics in nitrogen-limited fermentations of S. cerevisiae. The goodness-of-fit of the herewith proposed model is superior to that of previously published models, offering the means to predict, and thus control, problematic fermentations.IMPORTANCEProblematic fermentations still occur in the winemaking industrial practise. Problems include sluggish rates of fermentation, which have been linked to insufficient levels of assimilable nitrogen. Data and relevant models can help anticipate poor fermentation performance. In this work, we proposed a model to predict biomass growth and fermentation rate under nitrogen-limited conditions and tested its performance with previously published experimental data. Our results show that the well-known Monod law does not suffice to explain biomass formation. A second term accounting for carbohydrate accumulation is required to predict successfully, and thus control, problematic fermentations.