Physiology of Seed Dormancy and Germination-A Review

Seed dormancy is considered as an inherent property which outlines the environmental conditions in which the seed is accomplished to evolve. To better understand seed dormancy mechanisms, a series of rigorous studies examining seed metabolism in relation to gibberellin and abscisic acid have been organised. Abscisic acid is a hormone involved in the formation of primary dormancy, whereas gibberellins are a hormone involved in the induction of germination. During changes in dormancy certain variations in sensitivity can be observed. In the higher plants as the dormancy is present across all climatic regions differing responses in the environment has resulted due to adaptation. As a result of this variance, incubation is timed to avoid adverse weather conditions in order to promote reproductive growth and plant establishment. All molecular mechanisms emphasizing kernel latency initiation, conservation and improvement play a large part in the evolution and adaptation of these seeds and plants and their importance is indescribable. Together genetic and environmental factors are liable for triggering seed dormancy. For the induction of seed dormancy and besides its release the balance between the intensity of ABA plus GA remain in charge. There is a triphasic pattern of germination including imbibition i.e rapid uptake of water, enzyme activation and initiation of embryo growth resulting in the radicle protrusion. The dormancy state is regulated not only by the seed maturation environment, but it also changes over time after shedding in a way that is determined by the ambient environment.

Effect of K and Zn Application on Biometric and Physiological Parameters of Different Maize Genotypes

Potassium (K) and zinc (Zn) are mineral nutrients required for adequate plant growth, enzyme activation, water retention and photosynthetic activities. However, Pakistani soils are alkaline and have serious problems regarding Zn deficiency. The current study aims at finding the nutrient–nutrient interaction of K and Zn to affect maize plants’ (i) physiological processes and (ii) productivity. For this purpose, a pot experiment was conducted at the research area of the Department of Soil Science, Faculty of Agricultural Science and Technology, Bahauddin Zakariya University, Multan. Two maize genotypes, DK-6142 (hybrid) and Neelam (non-hybrid), were used with three K fertilizer doses, i.e., 0, 60 and 100 kg ha−1 in all possible combinations with three Zn fertilizer doses, i.e., 0, 16 and 24 kg ha−1. The treatments were replicated under a completely randomized block design. The results elucidated that the combined application of K and Zn with K60 + Zn16 treatment significantly increased agronomic, productive, and physiological attributes. It has improved fresh biomass (89%), dry biomass (94%), membrane stability index (142%), relative water content (200%) and chlorophyll contents (191%) as compared to the control. Moreover, the mineral uptake of K and Zn was significantly improved with their maximum fertilization rate in hybrid genotype compared to non-hybrid and CK.

Solvation dynamics-powered structure and function of multi-molecular cellular systems exemplified by non-equilibrium cereblon-degrader-CK1α ternary complex formation

Cellular functions are executed via a form of analog computing that is based on the switchable covalent and non-covalent states of multi-molecular fluxes (i.e., time-dependent species/state concentrations) operating in the non-linear dynamics regime. We and others have proposed that the non-covalent states and state transitions of aqueous fluxes are powered principally by the storage and release of potential energy to/from the anisotropic H-bond network of solvating water (which we refer to as the 'solvation field'), which is a key tenet of a first principles theory on cellular structure and function (called Biodynamics) that we outlined previously. This energy is reflected in water occupancy as a function of solute surface position, which can be probed computationally using WATMD software. In our previous work, we used this approach to deduce the structural dynamics of the COVID main protease, including substrate binding-induced enzyme activation and dimerization, and product release-induced dimer dissociation. Here, we examine: 1) The general relationships between surface composition/topology and solvation field properties for both high and low molecular weight (HMW and LMW) solutes. 2) The general means by which structural dynamics are powered by solvation free energy, which we exemplify via binding between the E3 ligase CUL4A/RBX1/DDB1/CRBN, LMW degraders, and substrates. We propose that degraders organize the substrate binding surface of cereblon toward complementarity with native and neo substrates, thereby speeding the association rate constant and incrementally slowing the dissociation rate constant. 3) Structure-activity relationships (SAR) based on complementarity between the solvation fields of cognate protein-ligand partners exemplified via LMW degraders.

Co-Application of Charcoal and Wood Ash to Improve Potassium Availability in Tropical Mineral Acid Soils

Potassium (K) is a macronutrient required by plants for energy production, enzyme activation, formation of cell wall, production of protein, and photosynthesis. However, K in the soil solution is leached from the rhizosphere before it interacts with soil colloids because of the abundance of kaolinite clay minerals in mineral acid soils such as Ultisols and Oxisols. These soils are highly weathered, low in organic matter, low in pH, but high aluminium (Al), and iron (Fe) ions. As a result, K becomes unavailable for plants, and this affects crop production and farmers’ profitability. This problem has steered the attention to the application of amendments to minimise K loss. Animal manures, plant residues, and composts applications are some of the corrective measures taken to improve the K availability in tropical acid soils. However, there is dearth of information on co-application of charcoal and wood ash as soil amendments to improve the K availability and the changes they cause to the dynamic equilibrium of K in mineral acid soils. Hence, this review discusses the dynamics, availability of K, and proposed mechanisms involved when charcoal and wood ash are used to amend tropical acid soils. The optimisation and understanding of the role of charcoal and wood ash co-application as soil amendments have potential benefits to improve the K availability and physicochemical properties of mineral acid soils.

The novel GCK variant p.Val455Leu associated with hyperinsulinism is susceptible to allosteric activation and is conducive to weight gain and the development of diabetes

Aims/hypothesis The mammalian enzyme glucokinase (GK), expressed predominantly in liver and pancreas, plays an essential role in carbohydrate metabolism. Monogenic GK disorders emphasise the role of GK in determining the blood glucose set point. Methods A family with congenital hyperinsulinism (CHI) was examined for GCK gene variants by Sanger sequencing. A combined approach, involving kinetic analysis (also using GK activators and inhibitors), intracellular translocation assays, insulin secretion measurements and structural modelling, was used to investigate the novel variant compared with known variants. Results We report on the novel gain-of-function GCK variant p.Val455Leu (V455L), inherited as an autosomal dominant trait in a German family with CHI and concomitant obesity (fasting blood glucose 2.1 mmol/l, BMI 45.0 kg/m2, HOMA-IR 1.5 in an adult female family member); one male family member developed type 2 diabetes until age 35 years (with fasting glucose 2.8–3.7 mmol/l, BMI 38.9 kg/m2, HOMA-IR 4.6). Kinetic characterisation of the V455L variant revealed a significant increase in glucose affinity (glucose concentration at which reaction rate is half its maximum rate [S0.5]: mutant 2.4 ± 0.3 mmol/l vs wild-type 7.6 ± 1.0 mmol/l), accompanied by a distinct additive susceptibility to both the endogenous activator fructose 2,6-bisphosphatase and the synthetic allosteric activator RO-28-1675. The effect of RO-28-1675 was more pronounced when compared with the previously known GK variants V455M and V455E. Binding to the inhibitor glucokinase regulatory protein was unimpaired for V455L and V455E but was reduced for V455M, whereas mannoheptulose inhibited all GK variants and the wild-type enzyme. Structural analyses suggested a role for residue 455 in rearrangements between the inactive and active conformations of GK and also in allosteric activation. Comparison with V455M and V455E and an overview of activating GK variants provided a context for the novel sequence aberration in terms of altered GK enzyme characteristics caused by single amino acid changes. Conclusion/interpretation We provide new knowledge on the structure–function relationship of GK, with special emphasis on enzyme activation, potentially yielding fresh strategic insights into breaking the vicious circle of fluctuating blood glucose levels and the attendant risk of long-lasting metabolic changes in both CHI and type 2 diabetes. Graphical abstract

Influence of Various Methods of Zinc Fertilization on Growth and Yield of Finger Millet (Eleusine coracana) Varieties

Background: Zn deficiency was predominant in soils of Chittoor district of Andhra Pradesh, which causes yield reduction in most of the crops especially in finger millet. Zinc has important role in enzyme activation viz., oxidoreductase, transferases, hydrolases, lyases, isomerases and ligases. The deficient soil gives us the zinc deficient food which is said to be the major root cause for malnutrition among the children. Hence present study was intended to find out most appropriate method and time of zinc fertilization for higher productivity, grain quality and zinc fortification with two major finger millet varieties viz., vakula and tirumala. Methods: The field experiment was laid out in split plot design with three replications and two varieties viz., vakula (V1) and tirumala (V2) with seven zinc application treatments which includes: control (T1); NPK (30-30-20) + FYM @ 10t ha-1 (T2); T2 + soil application (SA) of ZnSO4 @ 25 kg ha-1 as basal (T3); T2 + SA of chelated zinc sulphate @ 5 kg ha-1 as basal (T4); T2 + FA of 0.2% ZnSO4 at ear head emergence stage (T5); T2 + foliar application (FA) of 0.2% ZnSO4 at grain filling stage (T6); T2 + FA of 0.2% ZnSO4 at ear head emergence and grain filling stages (T7). Result: Foliar application of 0.2% ZnSO4 at ear head emergence and grain filling stages registered significantly highest grain and straw yield of 3150 kg ha-1 and 7364 kg ha-1, respectively compared to control and other zinc fertilization treatments. Between the two tested varieties tirumala variety recorded higher grain yield (2298 kg ha-1) compared to vakula variety (2230 kg ha-1).

S100 Proteins in Pancreatic Cancer: Current Knowledge and Future Perspectives

Pancreatic cancer (PC) is a highly malignant tumor occurring in the digestive system. Currently, there is a lack of specific and effective interventions for PC; thus, further exploration regarding the pathogenesis of this malignancy is warranted. The S100 protein family, a collection of calcium-binding proteins expressed only in vertebrates, comprises 25 members with high sequence and structural similarity. Dysregulated expression of S100 proteins is a biomarker of cancer progression and prognosis. Functionally, these proteins are associated with the regulation of multiple cellular processes, including proliferation, apoptosis, growth, differentiation, enzyme activation, migration/invasion, Ca2+ homeostasis, and energy metabolism. This review highlights the significance of the S100 family in the diagnosis and prognosis of PC and its vital functions in tumor cell metastasis, invasion and proliferation. A further understanding of S100 proteins will provide potential therapeutic targets for preventing or treating PC.