Water-use efficiency (WUE) is often considered an important determinant of yield under stress and even as a component of crop drought resistance. It has been used to imply that rainfed plant ...production can be increased per unit water used, resulting in “more crop per drop”.
This opinionated review argues that selection for high WUE in breeding for water-limited conditions will most likely lead, under most conditions, to reduced yield and reduced drought resistance. As long as the biochemistry of photosynthesis cannot be improved genetically, greater genotypic transpiration efficiency (TE) and WUE are driven mainly by plant traits that reduce transpiration and crop water-use, processes which are crucially important for plant production. Since biomass production is tightly linked to transpiration, breeding for maximized soil moisture capture for transpiration is the most important target for yield improvement under drought stress. Effective use of water (EUW) implies maximal soil moisture capture for transpiration which also involves reduced non-stomatal transpiration and minimal water loss by soil evaporation. Even osmotic adjustment which is a major stress adaptive trait in crop plants is recognized as enhancing soil moisture capture and transpiration. High harvest index (HI) expresses successful plant reproduction and yield in terms of reproductive functions and assimilate partitioning towards reproduction. In most rainfed environments crop water deficit develops during the reproductive growth stage thus reducing HI. EUW by way of improving plant water status helps sustain assimilate partitions and reproductive success. It is concluded that EUW is a major target for yield improvement in water-limited environments. It is not a coincidence that EUW is an inverse acronym of WUE because very often high WUE is achieved at the expense of reduced EUW.
Summary
Women have a clinical advantage over men in relation to atherosclerotic cardiovascular disease (CVD) (morbidity and mortality). This advantage disappears once women become older, and in their ...seventh decade, the risk to develop CVD equals men at that age. There have been several theories about this gender difference that were related to hormones, and the different morphology and physiology that characterize the cardiovascular system in women. In this review, the different mechanisms will be reviewed and discussed.
In recent years, single-molecule and single-particle fluorescence microscopy has emerged as a tool to investigate chemical systems. After an initial lag of over a decade with respect to biophysical ...studies, this powerful imaging technique is now revealing mechanisms of 'classical' organic reactions, spatial distribution of chemical reactivity on surfaces and the phase of active catalysts. The recent advance into commercial imaging systems obviates the need for home-built laser systems and thus opens this technique to traditionally trained synthetic chemists. We discuss the requisite photophysical and chemical properties of fluorescent reporters and highlight the main challenges in applying single-molecule techniques to chemical questions. The goal of this Perspective is to provide a snapshot of an emerging multidisciplinary field and to encourage broader use of this young experimental approach that aids the observation of chemical reactions as depicted in many textbooks: molecule by molecule.
After a decade of genetic manipulation and improvement, triticale stand out as a crop of high biomass and grain yield potential which generally surpass that of wheat. Its high productivity is most ...likely derived from high rates of carbon assimilation linked to stomatal physiology and probably low respiration rate. Being a derivative of rye, triticale has always been assumed to be relatively resistant to abiotic stress. The last review of triticale adaptation to abiotic stress as published by Jessop (1996) pointed at its general and specific fitness to harsh growing conditions. This review as based on additional data published in the last 20 years indicates that triticale retain good to excellent adaptation to conditions of limited water supply and problem soils which involve salinity, low pH, defined mineral toxicities and deficiencies and waterlogging. Despite the understandable expectations, freezing tolerance of triticale was not found to be up to the level of rye. The freezing tolerance of the rye complement in triticale is inhibited by unknown factors on the wheat parent genome. Any given triticale cultivar or selection cannot be taken a priori as being stress resistant. Research has repeatedly shown that triticale presented large genetic diversity for abiotic stress resistance and most likely this diversity has not yet been fully explored due to the very limited research and the small studied sample of the potential triticale germplasm. Triticale is a valuable stress tolerant cereal on its own accord and a potential genetic resource for breeding winter and spring cereals. Because of its high productivity and resilience it might become as important as wheat or better on a global scale if its grain technological quality will be improved to the level of wheat.
Abstract Statins have been demonstrated to significantly affect the prognosis and outcome of patients with risk factors to atherosclerosis (in primary and secondary prevention trials). Several ...clinical and recently basic studies have suggested an extra-beneficial effect of the statins in the prevention of atherosclerosis and coronary artery disease. These studies showed that statins may affect the cardiovascular system beyond their effect on the lipid profile, and it was suggested that they affect the immunological system and vascular inflammation. Many of the beneficial pleiotropic effects of statins occur as a result of modulated endothelial function and reduced inflammatory processes. Attempting to understand these properties of statins is an exciting field of research that will also improve our understanding of vascular biology in health and disease, and thus enable the better use of this drug class in clinical practice.
Astrocytes regulate the response of the central nervous system to disease and injury and have been hypothesized to actively kill neurons in neurodegenerative disease
. Here we report an approach to ...isolate one component of the long-sought astrocyte-derived toxic factor
. Notably, instead of a protein, saturated lipids contained in APOE and APOJ lipoparticles mediate astrocyte-induced toxicity. Eliminating the formation of long-chain saturated lipids by astrocyte-specific knockout of the saturated lipid synthesis enzyme ELOVL1 mitigates astrocyte-mediated toxicity in vitro as well as in a model of acute axonal injury in vivo. These results suggest a mechanism by which astrocytes kill cells in the central nervous system.
Conspectus Organoboron compounds and heterocycles are powerful building blocks and precursors for organic synthesis, including for drug discovery and agrochemical and material synthesis. The common ...strategy for the synthesis of borylated heterocycles involves two separate synthetic steps: first, synthesis of the heterocyclic core, and second, borylation of the core through established methods such as transition-metal-catalyzed C–H or C–X activation/borylation or lithiation/borylation. In this Account, we describe our laboratory’s development of borylative heterocyclization reactions that access the heterocyclic core and install boron in one synthetic step. These methods provide complementary bond disconnections, regiochemistry, and functional-group compatibility to current methods. We describe our methods with two categories: a direct borylation method that refers to addition reactions starting from a preformed B–element σ bond, which is essential in the mechanistic route to product formation, and a formal borylation method that refers to addition reactions that do not require formation of a B–element bond but instead proceed through carbon–carbon π-bond activation by an electrophilic boron source followed by dealkylation or deacylation. Through electrophilic activation of the alkyne rather than activation of the B–element bond, formal borylation provides a complementary strategy toward neutral organoboron reagents. We first studied direct oxyboration toward the formation of borylated benzofurans, where a preformed boron–oxygen σ bond is added across an alkyne activated by a carbophilic gold catalyst. We describe detailed mechanistic and kinetic studies of this class of reactions. Application of the knowledge gained from these studies aided in the future development of additional direct borylation reactions involving boron–nitrogen and boron–oxygen σ bonds to form borylared indoles and isoxazoles, respectively. Formal addition of boron/oxygen equivalents to effect oxyboration to form borylated lactones from o-alkynyl esters is then described. This class of reactions takes advantage of bifunctional ClBcat as a carbophilic carbon–carbon π-bond activator and eventual dealkylating agent. We describe our motivation in developing this new class of catalyst-free borylation reactions and subsequently applying the formal borylation strategy to the thioboration of o-alkynylthioanisole substrates to form borylated benzothiophenes. We then proceed to describe our investigations into the details of the mechanism of the formal thioboration reaction. These collaborative mechanistic studies included experimental and computational findings that elucidated the rate-determining step and intermediates of the reaction. These studies further compared different boron sources as electrophiles, including those used in other known reactions, providing fundamental knowledge about the capabilities of commercially available boron reagents toward borylative heterocyclization. Our findings provide guiding principles for reaction design and information leading toward the design of a diverse set of boron–heteroatom addition reactions and their formal equivalents that proceed through borylative heterocyclization.
The spinal cord is a fascinating structure that is responsible for coordinating movement in vertebrates. Spinal motor neurons control muscle activity by transmitting signals from the spinal cord to ...diverse peripheral targets. In this study, we profiled 43,890 single-nucleus transcriptomes from the adult mouse spinal cord using fluorescence-activated nuclei sorting to enrich for motor neuron nuclei. We identified 16 sympathetic motor neuron clusters, which are distinguishable by spatial localization and expression of neuromodulatory signaling genes. We found surprising skeletal motor neuron heterogeneity in the adult spinal cord, including transcriptional differences that correlate with electrophysiologically and spatially distinct motor pools. We also provide evidence for a novel transcriptional subpopulation of skeletal motor neuron (γ*). Collectively, these data provide a single-cell transcriptional atlas ( http://spinalcordatlas.org ) for investigating the organizing molecular logic of adult motor neuron diversity, as well as the cellular and molecular basis of motor neuron function in health and disease.
A catalyst-free oxyboration reaction of alkynes is developed. The resulting borylated isocoumarins and 2-pyrones are isolated as boronic acids, pinacolboronate esters, or potassium ...organotrifluoroborate salts, providing a variety of bench-stable organoboron building blocks for downstream functionalization. This method has functional group compatibility, is scalable, and proceeds with readily available materials: B-chlorocatecholborane and methyl esters. Mechanistic studies indicate that the B-chlorocatecholborane acts as a carbophilic Lewis acid toward the alkyne, providing a mechanistically distinct pathway for oxyboration that avoids B–O σ bond formation and enables this catalyst-free route.
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