A natural consequence of everyday tissue metabolism is cell injury or stress. This injury activates a canonical immune-mediated inflammatory response in order to achieve tissue repair so that ...homeostasis is maintained. With aging there is increased tissue injury and therefore increasing demands placed on an immune system, which itself is aging (immunosenescence). Thus, the increased reparative demands are reflected by an increased inflammatory load both locally and systemically. Eventually, if the reparative demands are excessive, the aging immune system is overwhelmed and disease ensues. In the macula this age-related failure in repair gives rise to age-related macular degeneration (AMD). The hypothesis proposed herein is therefore, that AMD is due to age-related failure of tissue repair and the chronic inflammation associated with this failure (‘inflammaging’) is both a surrogate and biomarker of this reparative failure and not in itself the primary cause of disease. Such a hypothesis can be applied to all the diseases of aging and by extension suggests that effective therapies should be aimed at facilitating repair through immunotherapy, possibly and perhaps controversially, through the promotion of inflammation rather than the current approach of its inhibition (anti-inflammatory strategies), the latter which can ultimately only hinder the repair process and thereby lead to the persistence of disease.
Recruitment of microorganisms to the rhizosphere varies among plant genotypes, yet an understanding of whether the microbiome can be altered by selection on the host is relatively unknown. Here, we ...performed a common garden study to characterize recruitment of rhizosphere microbiome, functional groups, for 20 expired Plant Variety Protection Act maize lines spanning a chronosequence of development from 1949 to 1986. This time frame brackets a series of agronomic innovations, namely improvements in breeding and the application of synthetic nitrogenous fertilizers, technologies that define modern industrial agriculture. We assessed the impact of chronological agronomic improvements on recruitment of the rhizosphere microbiome in maize, with emphasis on nitrogen cycling functional groups. In addition, we quantified the microbial genes involved in nitrogen cycling and predicted functional pathways present in the microbiome of each genotype. Both genetic relatednesses of host plant and decade of germplasm development were significant factors in the recruitment of the rhizosphere microbiome. More recently developed germplasm recruited fewer microbial taxa with the genetic capability for sustainable nitrogen provisioning and larger populations of microorganisms that contribute to N losses. This study indicates that the development of high-yielding varieties and agronomic management approaches of industrial agriculture inadvertently modified interactions between maize and its microbiome.
The magnetization of a magnetic material can be reversed by using electric currents that transport spin angular momentum. In the reciprocal process a changing magnetization orientation produces ...currents that transport spin angular momentum. Understanding how these processes occur reveals the intricate connection between magnetization and spin transport, and can transform technologies that generate, store or process information via the magnetization direction. Here we explain how currents can generate torques that affect the magnetic orientation and the reciprocal effect in a wide variety of magnetic materials and structures. We also discuss recent state-of-the-art demonstrations of current-induced torque devices that show great promise for enhancing the functionality of semiconductor devices.
The endocannabinoid system Kilaru, Aruna; Chapman, Kent D
Essays in biochemistry,
09/2020, Letnik:
64, Številka:
3
Journal Article
Recenzirano
Thirty years ago, the discovery of a cannabinoid (CB) receptor that interacts with the psychoactive compound in Cannabis led to the identification of anandamide, an endogenous receptor ligand or ...endocannabinoid. Research on endocannabinoids has since exploded, and additional receptors along with their lipid mediators and signaling pathways continue to be revealed. Specifically, in humans, the release of endocannabinoids from membrane lipids occurs on demand and the signaling process is rapidly attenuated by the breakdown of the ligand suggesting a tight regulation of the endocannabinoid system (ECS). Additionally, the varying distribution of CB receptors between the central nervous system and other tissues allows for the ECS to participate in a wide range of cognitive and physiological processes. Select plant-derived 'phyto'cannabinoids such as Δ-9-tetrahydrocannabinol (Δ9-THC) bind to the CB receptors and trigger the ECS, and in the case of Δ9-THC, while it has therapeutic value, can also produce detrimental effects. Current research is aimed at the identification of additional phytocannabinoids with minimal psychotropic effects with potential for therapeutic development. Although decades of research on the ECS and its components have expanded our understanding of the mechanisms and implications of endocannabinoid signaling in mammals, it continues to evolve. Here, we provide a brief overview of the ECS and its overlap with other related lipid-mediated signaling pathways.
This article concerns the positive feedback bias, which occurs when White instructors supply selectively more praise and less criticism to ethnic minority learners relative to White learners. The ...positive bias is reliable and enduring and affects feedback to various ethnic groups in North America and in Europe. The model of threat-infused intergroup feedback (MOTIIF) is introduced to explain the positive bias. MOTIIF integrates research on feedback practices, interracial dynamics, self-image maintenance, and psychosocial resources to explain why and when the bias is expressed. According to MOTIIF the positive bias is driven mainly by racial anxiety, the concern of many White people that they will reveal self-compromising prejudices, to others or to themselves, when engaging with ethnic minority persons. Inflated praise and muted criticism to ethnic minority learners serve, per MOTIIF, to quell racial anxiety. The article reviews evidence of the positive bias and relates it to the MOTIIF framework. It also discusses how the positive bias can affect ethnic minority learners; how it diminishes their trust in feedback, erodes their self-esteem, increases their stress, and potentially, undermines their learning. The article draws on MOTIIF to consider potential solutions to the positive bias and to recommend future research.
Triacylglycerols from plants, familiar to most people as vegetable oils, supply 25% of dietary calories to the developed world and are increasingly a source for renewable biomaterials and fuels. ...Demand for vegetable oils will double by 2030, which can be met only by increased oil production. Triacylglycerol synthesis is accomplished through the coordinate action of multiple pathways in multiple subcellular compartments. Recent information has revealed an underappreciated complexity in pathways for synthesis and accumulation of this important energy-rich class of molecules.
The lipodystrophy protein SEIPIN is important for lipid droplet (LD) biogenesis in human and yeast cells. By contrast to the single SEIPIN genes in humans and yeast, there are three SEIPIN homologues ...in Arabidopsis thaliana, designated At-SEIPIN1, At-SEIPIN2 and At-SEIPIN3. Here, a yeast (Saccharomyces cerevisiae) SEIPIN-deletion-mutant strain and a tobacco (Nicotiana benthamiana) transient expression system were used to test the ability of Arabidopsis SEIPINs to influence LD morphology. In both species, expression of At-SEIPIN1 promoted accumulation of large-sized lipid droplets, while expression of At-SEIPIN2 and especially At-SEIPIN3 promoted small LDs. Arabidopsis SEIPINs increased triacylglycerol levels and altered composition. In tobacco, ER-localized SEIPINs reorganized the normal, reticulated ER structure into discrete ER domains that co-localized with LDs. Amino-terminal deletions and swapping experiments of At-SEIPIN 1 and 3, revealed that this region of SEIPIN determines LD size. Ectopic over-expression of At-SEIPIN1 in Arabidopsis resulted in increased numbers of large LDs in leaves, as well as in seeds, and increased seed oil content by up to 10% over wild-type seeds. By contrast, RNAi suppression of At-SEIPIN1 resulted in smaller seeds and, as a consequence, a reduction in the amount of oil per seed compared with wild-type.
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