Effects of exogenous application of five antioxidants on vigour, viability, oxidative metabolism and germination enzymes in aged cabbage and lettuce seeds

Ageing induces modifications capable of compromising seed vigour and viability. This study investigated the effects of exogenous application of five antioxidants: ascorbic acid (AA), gallic acid (GA), reduced glutathione (GSH), trolox and glycerol, on physical and biochemical lesions induced by controlled deterioration (CD) in Brassica oleracea (cabbage) and Lactuca sativa (lettuce) seeds. The antioxidants were applied at 0.2, 0.4 and 0.6 mM to fresh seeds and seeds subjected to CD: 75% viability (P75), 50% viability (P50) and 25% viability (P25); deionised water (DW) served as control. Controlled deterioration resulted in more abnormal seedlings production in cabbage than in lettuce seeds. Additionally, CD increased electrical conductivity (EC) and protein carbonylation (PC), lowered antioxidant and germination enzymes activities in both species but increased lipid peroxidation in lettuce seeds only. Exogenous application of antioxidants enhanced seed viability of cabbage at P25 and lettuce at P50 and P25; seedling vigour of fresh, P75 and P25 cabbage; P50 and P25 lettuce seeds. Electrolyte conductivity and lipid peroxidation were reduced by AA, GA, glycerol, GSH and trolox in lettuce seeds, while PC was reduced by GA, glycerol and GSH in both species

Oxidative Stress, Ageing and Methods of Seed Invigoration: An Overview and Perspectives

The maintenance of seed quality during the long-term conservation of plant genetic resources is crucial for averting the projected food crises that are linked to the changing climate and rising world population. However, ageing-induced loss of seed vigour and viability during storage remains an inevitable process that compromises productivity in several orthodox-seeded crop species. Seed ageing under prolonged storage, which can occur even under optimal conditions, induces several modifications capable of causing loss of intrinsic physiological quality traits, including germination capacity and vigour, and stand establishment. The problems posed by seed ageing have motivated the development of various techniques for mitigating their detrimental effects. These invigoration techniques generally fall within one of two categories: (1) priming or pre-hydrating seeds in a solution for improved post-harvest performance, or (2) post-storage reinvigoration which often involves soaking seeds recovered from storage in a solution. Seed priming methods are generally divided into classical (hydropriming, osmopriming, redox priming, biostimulant priming, etc.) and advanced (nanopriming, magnetopriming and priming using other physical agents) techniques. With the increasing popularity of seed invigoration techniques to achieve the much-desired enhanced productivity and resilience in the face of a changing climate, there is an urgent need to explore these techniques effectively (in addition to other important practices such as plant breeding, fertilizer application, and the control of pests and diseases). This review aims to provide an overview of ageing in orthodox seeds and invigoration techniques that can enhance desirable agronomic and physiological characters

A critical comparative review of evidence on alternative instruments for supporting research and innovation in agri-food systems in the Global South

Financial support is a critical enabling factor for healthy agri-food innovation systems, particularly within resource-limited settings, though additional forms of support are also necessary. This motivated a critical comparative review of evidence in peer-reviewed and gray literature on the range of instruments that support innovation in agri-food systems in the Global South, toward achieving sustainable agriculture intensification. The main aim is to provide recommendations to innovation managers on the choice of different instruments for supporting innovation. The key guiding questions for the comparative analysis were whether the instrument fosters uptake of innovation and whether it promotes inclusive development. A review of the literature was supplemented with a scan of websites for sources of peer-reviewed and gray literature documenting the application of the 12 selected instruments. The study revealed three categories of instruments: (Type A) those that support entrepreneurship; (Type B) those that primarily finance innovation; and (Type C) those that support innovation in real-life contexts. Our analysis indicates that innovation managers and funders need to select instruments that are likely to fit the specific context as well as to address the mandates of their organizations, and in so doing, they must consider how to ensure the sustainability of their investments and meet the needs of their beneficiaries. This review represents one of a handful that have compared the use of multiple instruments across multiple continents in the Global South, and can serve as an important decision-making tool for investors and funders looking to invest in agri-food innovation systems

Alpha-aminoisobutyric acid uptake in primary cultures of astrocytes

Homotypically pure cultures of rat brain astrocytes were used to examine some aspects of non-neuronal A-system (alanine preferring) amino acid uptake. The Asystem specific probe, alpha-aminoisobutyric acid is transported rapidly, and a steady state distribution ratio of 9–25 is reached after 30 minute incubations. Kinetic estimates derived from uptake progress curves indicated a K m of 1.35 mM and a V max of 133 nmol/min/mg protein. Uptake is reduced in the absence of either Na + or K + . Elevations in extracellular K + , a putative metabolic modulator of neuroglia, did not affect uptake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45428/1/11064_2004_Article_BF00965086.pd

Alternating Magnetic Field Controlled, Multifunctional Nano-Reservoirs: Intracellular Uptake and Improved Biocompatibility

Biocompatible magnetic nanoparticles hold great therapeutic potential, but conventional particles can be toxic. Here, we report the synthesis and alternating magnetic field dependent actuation of a remotely controllable, multifunctional nano-scale system and its marked biocompatibility with mammalian cells. Monodisperse, magnetic nanospheres based on thermo-sensitive polymer network poly(ethylene glycol) ethyl ether methacrylate-co-poly(ethylene glycol) methyl ether methacrylate were synthesized using free radical polymerization. Synthesized nanospheres have oscillating magnetic field induced thermo-reversible behavior; exhibiting desirable characteristics comparable to the widely used poly-N-isopropylacrylamide-based systems in shrinkage plus a broader volumetric transition range. Remote heating and model drug release were characterized for different field strengths. Nanospheres containing nanoparticles up to an iron concentration of 6 mM were readily taken up by neuron-like PC12 pheochromocytoma cells and had reduced toxicity compared to other surface modified magnetic nanocarriers. Furthermore, nanosphere exposure did not inhibit the extension of cellular processes (neurite outgrowth) even at high iron concentrations (6 mM), indicating minimal negative effects in cellular systems. Excellent intracellular uptake and enhanced biocompatibility coupled with the lack of deleterious effects on neurite outgrowth and prior Food and Drug Administration (FDA) approval of PEG-based carriers suggest increased therapeutic potential of this system for manipulating axon regeneration following nervous system injury

Presynaptic Nicotinic α7 and Non-α7 Receptors Stimulate Endogenous GABA Release from Rat Hippocampal Synaptosomes through Two Mechanisms of Action

BACKGROUND: Although converging evidence has suggested that nicotinic acetylcholine receptors (nAChR) play a role in the modulation of GABA release in rat hippocampus, the specific involvement of different nAChR subtypes at presynaptic level is still a matter of debate. In the present work we investigated, using selective α7 and α4β2 nAChR agonists, the presence of different nAChR subtypes on hippocampal GABA nerve endings to assess to what extent and through which mechanisms they stimulate endogenous GABA release. METHODOLOGY/FINDINGS: All agonists elicited GABA overflow. Choline (Ch)-evoked GABA overflow was dependent to external Ca(2+), but unaltered in the presence of Cd(2+), tetrodotoxin (TTX), dihydro-β-erythroidine (DHβE) and 1-(4,4-Diphenyl-3-butenyl)-3-piperidinecarboxylic acid hydrochloride SKF 89976A. The effect of Ch was blocked by methyllycaconitine (MLA), α-bungarotoxin (α-BTX), dantrolene, thapsigargin and xestospongin C, suggesting that GABA release might be triggered by Ca(2+) entry into synaptosomes through the α7 nAChR channel with the involvement of calcium from intracellular stores. Additionally, 5-Iodo-A-85380 dihydrochloride (5IA85380) elicited GABA overflow, which was Ca(2+) dependent, blocked by Cd(2+), and significantly inhibited by TTX and DHβE, but unaffected by MLA, SKF 89976A, thapsigargin and xestospongin C and dantrolene. These findings confirm the involvement of α4β2 nAChR in 5IA85380-induced GABA release that seems to occur following membrane depolarization and opening calcium channels. CONCLUSIONS/SIGNIFICANCE: Rat hippocampal synaptosomes possess both α7 and α4β2 nAChR subtypes, which can modulate GABA release via two distinct mechanisms of action. The finding that GABA release evoked by the mixture of sub-maximal concentration of 5IA85380 plus sub-threshold concentrations of Ch was significantly larger than that elicited by the sum of the effects of the two agonists is compatible with the possibility that they coexist on the same nerve terminals. These findings would provide the basis for possible selective pharmacological strategies to treat neuronal disorders that involve the dysfunction of hippocampal cholinergic system

Germination indices of orthodox seeds as influenced by controlled deterioration and cathodic water seed invigoration y

© 2020 Triveni Enterprises. All rights reserved. Aim: The aim of this study was to test the effects of priming on the germination of deteriorated orthodox seeds of five plant species. Methodology: The water content of seeds were raised to 14%, and the seeds then deteriorated to 50% viability at 40oC and 100% relative humidity. Deteriorated seeds and fresh seeds of test species were then primed with cathodic water, un-electrophorized calcium magnesium solution and deionised water. Unprimed fresh and unprimed controlled deteriorated seeds served as controls. Germination indices were determined. Results: In general, all priming treatments had positive effects on the germination indices of deteriorated seeds of all species, and a lesser extent on fresh seeds. However, seeds treated with cathodic water performed better than seeds treated with either CaMg solution or deionised water. While controlled deterioration reduced DNA concentrations and the DNA purity of seeds, priming, particularly with cathodic water had a protecting effect on DNA. Priming also boosted amylase activities in both fresh and deteriorated seeds. Interpretation: Results are consistent with cathodic water reducing oxidative stress during imbibition. Cathodic water seed priming, therefore, has the potential to play a significant role in the conservation of orthodox seeds