Intrinsically disordered proteins play a crucial role in cellular phase separation, yet the diverse molecular forces driving phase separation are not fully understood. It is of utmost importance to ...understand how peptide sequence, and particularly the balance between the peptides’ short- and long-range interactions with other peptides, may affect the stability, structure, and dynamics of liquid–liquid phase separation in protein condensates. Here, using coarse-grained molecular dynamics simulations, we studied the liquid properties of the condensate in a series of polymers in which the ratio of short-range dispersion interactions to long-range electrostatic interactions varied. As the fraction of mutations that participate in short-range interactions increases at the expense of long-range electrostatic interactions, a significant decrease in the critical temperature of phase separation is observed. Nevertheless, sequences with a high fraction of short-range interactions exhibit stabilization, which suggests compensation for the loss of long-range electrostatic interactions. Decreased condensate stability is coupled with decreased translational diffusion of the polymers in the condensate, which may result in the loss of liquid characteristics in the presence of a high fraction of uncharged residues. The effect of exchanging long-range electrostatic interactions for short-range interactions can be explained by the kinetics of breaking intermolecular contacts with neighboring polymers and the kinetics of intramolecular fluctuations. While both time scales are coupled and increase as electrostatic interactions are lost, for sequences that are dominated by short-range interactions, the kinetics of intermolecular contact breakage significantly slows down. Our study supports the contention that different types of interactions can maintain protein condensates, however, long-range electrostatic interactions enhance its liquid-like behavior.
•Sourcing and pricing decisions of competing retailers under supply disruption.•Game theoretic analysis of a retailer competing against a reliable supply chain.•Price adjustment as a risk contingency ...strategy resulting in profit improvement.•Competitive dynamics shaped by market size, procurement cost and disruption risk.•Framework derived based on combining pricing and sourcing strategies.
Supply disruption has become a critical concern for businesses around the world. The extant literature has dealt mainly with the sourcing decision for a price-taking retailer. In this paper, we study how a retailer can use pricing decisions along with sourcing strategies under disruption risk while competing against another retailer with a more reliable supply chain. The retailer uses two decision levers namely, price adjustment, and split of order between reliable but expensive supplier and/or cheap but unreliable supplier to compete in the end market. Our analyses show that the competitive dynamics is shaped by the cost structure of the players, relative market potential and disruption risk. We find that the retailer focuses on reliable supplies with less price adjustment when it enjoys procurement cost advantage and higher market potential. On the other hand, as the procurement cost advantage and market potential shifts to the competitor; the retailer opts for cheaper but risky supplies and relies on drastic price adjustments. These results have important managerial implications and provide critical guidelines for retailers involved in pricing and sourcing decisions under the threat of supply disruptions.
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•Phytic acid (PA) is generally considered as an antinutrient, though it also plays beneficial role in both plants and animals.•Phytic acid has beneficial as hypoglycemic, antioxidant ...and anti-bacterial agent.•In plant, it helps in seed germination and protect against biotic and abiotic stress.•Fine-tuning of PA can be done by physical, chemical and genetic intervention.
Phytic acid (PA), myo-inositol 1,2,3,4,5,6-hexakisphosphate is the principal storage compound of phosphorus (P) and account for 65%–85% of the seeds total P. The negative charge on PA attracts and chelates metal cations resulting in a mixed insoluble salt, phytate. Phytate contains six negatively charged ions, chelates divalent cations such as Fe2+, Zn2+, Mg2+, and Ca2+ rendering them unavailable for absorption by monogastric animals. This may lead to micronutrient deficiencies in humans since they lack the enzyme phytase that hydrolyzes phytate and releases the bound micronutrients. There are two main concerns about the presence of PA in human diet. The first is its negative impact on the bioavailability of several minerals and the second is the evidence of PA inhibiting various proteases essential for protein degradation and the subsequent digestion in stomach and small intestine. The beneficial role of PA has been underestimated due to its distinct negative consequences. PA is reported to be a potent natural plant antioxidant which plays a protective role against oxidative stress in seeds and preventive role in various human diseases. Recently beneficial roles of PA as an antidiabetic and antibacterial agent has been reported. Thus, the development of grains with low-PA and modified distribution pattern can be achieved through fine-tuning of its content in the seeds.
Recently synthesized two-dimensional hydrogen boride (HB) with a hexagonal boron network offers excellent opportunities for nanoscale electronic device applications. Herein, we have proposed a type ...of field-effect transistor (FET) nanodevice based on a two-dimensional HB sheet for individual identification of amino acids. Using first-principles consistent-exchange van der Waals density-functional (vdW-DF-cx) calculations, we have studied the effects produced by the adsorption of each amino acid on the electronic properties of the HB-based nanodevice for its detection. The adsorption energies, adsorption heights, and the charge transfer of each amino acid can be deliberated as demonstrative of all 10 amino acids: alanine (Ala), arginine (Arg), aspartic (Asp), glutamic acid (Glu), glycine (Gly), histidine (His), lysine (Lys), phenylalanine (Phe), proline (Pro), and tyrosine (Tyr). Furthermore, the electronic transport properties of the HB nanodevice and HB + amino acid setup are studied by the nonequilibrium Green’s function (NEGF) formalism combined with the density functional theory (DFT) approach. Our results show that the adsorption of each amino acid on the HB nanodevice gives Fano resonance in the electronic transmission function. The sensitivity analysis and current–voltage (I–V) characteristic results indicate that selective detection of amino acids is possible. Thus, we believe that the HB-based device may be promising for the prospect of protein sequencing.
Hydrogen bonding in imidazole plays a key role in proton conduction and rotation of an imidazole molecule in the process results in the cleavage of hydrogen bonds between molecules. In the present ...work, we characterize proton transport and rotation energy barriers in imidazole chains by density functional theory. Our calculations show that propagation of an excess proton along the chain requires crossing of energy barriers, lower than 1 kcal/mol. The presence of the proton has stronger effect on the immediate neighboring imidazole molecules, and the effect is negligible after two molecules. The subsequent rotation of all imidazole molecules after the transfer of first proton is essential to allow the transfer the second proton. The presence of an excess proton in the chain leads to cleavage of hydrogen bonds and the rotation of neighboring imidazole molecule. Further, rotation of one imidazole molecule results in rotation of all molecules in the chain. The calculated rotational energy barriers in two-, three-, and four-imidazole-molecule chains are 8.0, 17.1, and 20.0 kcal, respectively, and are equivalent to the number of hydrogen bonds broken in the process. The rotational barrier is higher than the proton transport barrier along the hydrogen bond and, thus, is the rate-determining step of proton conduction.
Several γ-glutamyl compounds produced from gamma-glutamyltranspeptidase (GGT) have alluring features for food, pharmaceutical, and biotechnology applications. GGT from Bacillus altitudinis IHB B1644 ...was cloned, followed by an expression in pET-47b(+) Escherichia coli BL21(DE3). Recombinant GGT (BaGGT) gene subsisted of 1755 bp encoding protein with 585 amino acids, predicted molecular weight, and theoretical pI of 63.3 kDa, and 4.92, respectively. Ectopic expression resulted in inclusion bodies formation at 37 °C. The protein was solubilized and different strategies like dialysis, rapid dilution, and on-column refolding were tried to get active recombinant protein (BaGGT1). To get protein in soluble fraction, GGT was over expressed at low temperature (20 °C), and IPTG concentration (0.025 mM) (BaGGT2). The heterodimeric enzyme consisted of molecular weight of 40, and 22 kDa for large and small subunits, respectively. The specific activities for BaGGT1 and BaGGT2 were 263.9, and 497.45 U mg−1, respectively. BaGGT1 and BaGGT2 showed optimum temperature, and pH at 37 °C and 9, respectively. Km values of 0.8 and 0.2 mM, and Vmax of 666.67 and 333.33 U mg−1 of protein, were calculated for BaGGT1and BaGGT2, respectively. The results demonstrate potential of BaGGT in biosynthesis of γ-glutamyl compounds with industrial application.
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•Bacillus altitudinis IHBB1644 studied for γ-glutamyltranspeptidase(GGT) expression.•Expression was performed at 37 °C,0.5 mM (BaGGT1) IPTG and 20 °C, 0.025 mM (BaGGT2).•Optimum GGT activity was observed at 37 °C and pH 9.•Difference in kinetic parameters was observed for BaGGT1 and BaGGT2.•BaGGT could be a potential candidate for industrial GGT production.
Tomato is an important vegetable that is highly sensitive to drought (DR) stress which impairs the development of tomato seedlings. Recently, melatonin (ME) has emerged as a nontoxic, regulatory ...biomolecule that regulates plant growth and enhances the DR tolerance mechanism in plants. The present study was conducted to examine the defensive role of ME in photosynthesis, root architecture, and the antioxidant enzymes' activities of tomato seedlings subjected to DR stress. Our results indicated that DR stress strongly suppressed growth and biomass production, inhibited photosynthesis, negatively affected root morphology, and reduced photosynthetic pigments in tomato seedlings. Per contra, soluble sugars, proline, and ROS (reactive oxygen species) were suggested to be improved in seedlings under DR stress. Conversely, ME (100 µM) pretreatment improved the detrimental-effect of DR by restoring chlorophyll content, root architecture, gas exchange parameters and plant growth attributes compared with DR-group only. Moreover, ME supplementation also mitigated the antioxidant enzymes APX (ascorbate peroxidase), CAT (catalase), DHAR (dehydroascorbate reductase), GST (glutathione S-transferase), GR (glutathione reductase), MDHAR (monodehydroascorbate reductase), POD (peroxidase), and SOD (superoxide dismutase), non-enzymatic antioxidant AsA (ascorbate), DHA (dehydroascorbic acid), GSH (glutathione), and GSSG, (oxidized glutathione) activities, reduced oxidative damage EL (electrolyte leakage), H
O
(hydrogen peroxide), MDA (malondialdehyde), and O
(superoxide ion) and osmoregulation (soluble sugars and proline) of tomato seedlings, by regulating gene expression for
,
,
,
,
,
,
, and
. These findings determine that ME pretreatment could efficiently improve the seedlings growth, root characteristics, leaf photosynthesis and antioxidant machinery under DR stress and thereby increasing the seedlings' adaptability to DR stress.
Heat stress (HS) is one of the major abiotic stresses affecting the production and quality of wheat. Rising temperatures are particularly threatening to wheat production. A detailed overview of ...morpho-physio-biochemical responses of wheat to HS is critical to identify various tolerance mechanisms and their use in identifying strategies to safeguard wheat production under changing climates. The development of thermotolerant wheat cultivars using conventional or molecular breeding and transgenic approaches is promising. Over the last decade, different omics approaches have revolutionized the way plant breeders and biotechnologists investigate underlying stress tolerance mechanisms and cellular homeostasis. Therefore, developing genomics, transcriptomics, proteomics, and metabolomics data sets and a deeper understanding of HS tolerance mechanisms of different wheat cultivars are needed. The most reliable method to improve plant resilience to HS must include agronomic management strategies, such as the adoption of climate-smart cultivation practices and use of osmoprotectants and cultured soil microbes. However, looking at the complex nature of HS, the adoption of a holistic approach integrating outcomes of breeding, physiological, agronomical, and biotechnological options is required. Our review aims to provide insights concerning morpho-physiological and molecular impacts, tolerance mechanisms, and adaptation strategies of HS in wheat. This review will help scientific communities in the identification, development, and promotion of thermotolerant wheat cultivars and management strategies to minimize negative impacts of HS.
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