Breeding and Cereal Yield Progress Fischer, R.A; Edmeades, Gregory O
Crop science,
March 2010, Letnik:
50, Številka:
2
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
This paper reviews recent progress in wheat (Triticum aestivum L.), rice (Oryza sativa L.), and maize (Zea mays L.) yields resulting from substantial breeding efforts in mostly favorable environments ...and examines its physiological basis. Breeding and improved agronomy lift potential yield (PY), namely yield with the best variety and management in the absence of manageable abiotic and biotic stresses, and PY increase is a key component of progress in farm yield (FY), the other component being closure of the PY to FY gap. Changes in PY and FY are reviewed for several key production regions, namely the United Kingdom and the Yaqui Valley of Mexico for wheat, Japan and Central Luzon in the Philippines for rice, and Iowa and briefly sub-Saharan Africa for maize. The PY growth rates have fallen and are currently generally no more than 1% per annum and usually much less. The trajectory of FY with time often closely parallels PY, but, especially in developing countries, there remain large yield gaps. In at least one instance (maize in Iowa) the gap between PY and FY appears to be closing rapidly. Current genetic progress is linked to increased biomass accumulation, and this will remain the way forward in the future given the limits to increased harvest index (HI). There is evidence that recent progress is related to increased photosynthesis (e.g., greater radiation use efficiency (RUE) at the canopy level and/or maximum photosynthetic rate P(max) at saturating irradiance at the leaf level) before and around anthesis. There is no theoretical reason why this trend cannot continue, especially given the vast genetic resources already found within each crop species. However, it will not be easily or cheaply accomplished, so prospects for higher rates of potential yield growth appear to be limited, notwithstanding new molecular tools and claims to the contrary. Closing the yield gap, therefore, becomes more important. Many factors are involved, but breeding can also help farmers achieve this through, for example, improved host plant resistance.
Works without ruthenium as well: Dye-sensitized solar cells (DSSCs) incorporating metal-free organic dyes have been considerably improved in recent years. Various design strategies have been ...established and are employed successfully in the synthesis of novel sensitizers. In this Review, structure-property-efficiency correlations are deduced from a vast number of dyes, which should help to design new and highly efficient sensitizers.Dye-sensitized solar cells (DSSC) have attracted considerable attention in recent years as they offer the possibility of low-cost conversion of photovoltaic energy. This Review focuses on recent advances in molecular design and technological aspects of metal-free organic dyes for applications in dye-sensitized solar cells. Special attention has been paid to the design principles of these dyes and on the effect of various electrolyte systems. Cosensitization, an emerging technique to extend the absorption range, is also discussed as a way to improve the performance of the device. In addition, we report on inverted dyes for photocathodes, which constitutes a relatively new approach for the production of tandem cells. Special consideration has been paid to the correlation between the molecular structure and physical properties to their performance in DSSCs.
The oxidation of rocky planet surfaces and atmospheres, which arises from the twin forces of stellar nucleosynthesis and gravitational differentiation, is a universal process of key importance to ...habitability and exoplanet biosignature detection. Here we take a generalized approach to this phenomenon. Using a single parameter to describe the redox state, we model the evolution of terrestrial planets around nearby M stars and the Sun. Our model includes atmospheric photochemistry, diffusion and escape, line-by-line climate calculations, and interior thermodynamics and chemistry. In most cases, we find abiotic atmospheric buildup around M stars during the pre-main-sequence phase to be much less than calculated previously, because the planet's magma ocean absorbs most oxygen liberated from photolysis. However, loss of noncondensing atmospheric gases after the mantle solidifies remains a significant potential route to abiotic atmospheric subsequently. In all cases, we predict that exoplanets that receive lower stellar fluxes, such as LHS1140b and TRAPPIST-1f and g, have the lowest probability of abiotic buildup and hence may be the most interesting targets for future searches for biogenic . Key remaining uncertainties can be minimized in future by comparing our predictions for the atmospheres of hot, sterile exoplanets such as GJ1132b and TRAPPIST-1b and c with observations.
Single-cell analyses have revealed extensive heterogeneity between and within human tumours
, but complex single-cell phenotypes and their spatial context are not at present reflected in the ...histological stratification that is the foundation of many clinical decisions. Here we use imaging mass cytometry
to simultaneously quantify 35 biomarkers, resulting in 720 high-dimensional pathology images of tumour tissue from 352 patients with breast cancer, with long-term survival data available for 281 patients. Spatially resolved, single-cell analysis identified the phenotypes of tumour and stromal single cells, their organization and their heterogeneity, and enabled the cellular architecture of breast cancer tissue to be characterized on the basis of cellular composition and tissue organization. Our analysis reveals multicellular features of the tumour microenvironment and novel subgroups of breast cancer that are associated with distinct clinical outcomes. Thus, spatially resolved, single-cell analysis can characterize intratumour phenotypic heterogeneity in a disease-relevant manner, with the potential to inform patient-specific diagnosis.
Single-cell, spatially resolved omics analysis of tissues is poised to transform biomedical research and clinical practice. We have developed an open-source, computational histology topography ...cytometry analysis toolbox (histoCAT) to enable interactive, quantitative, and comprehensive exploration of individual cell phenotypes, cell-cell interactions, microenvironments, and morphological structures within intact tissues. We highlight the unique abilities of histoCAT through analysis of highly multiplexed mass cytometry images of human breast cancer tissues.
Gene technology has facilitated the biologization of manufacturing, i.e. the use and production of complex biological molecules and systems at an industrial scale. Monoclonal antibodies (mAbs) are ...currently the major class of biopharmaceutical products, but they are typically used to treat specific diseases which individually have comparably low incidences. The therapeutic potential of mAbs could also be used for more prevalent diseases, but this would require a massive increase in production capacity that could not be met by traditional fermenter systems. Here we outline the potential of plants to be used for the very-large-scale (VLS) production of biopharmaceutical proteins such as mAbs. We discuss the potential market sizes and their corresponding production capacities. We then consider available process technologies and scale-down models and how these can be used to develop VLS processes. Finally, we discuss which adaptations will likely be required for VLS production, lessons learned from existing cell culture-based processes and the food industry, and practical requirements for the implementation of a VLS process.
In the effort to generate sustainable clean energy from abundant resources such as water and carbon dioxide, solar fuel production-the combination of solar-light harvesting and the generation of ...efficient chemical energy carriers-by artificial molecular photosystems is very attractive. Molecular constituents that display attractive features for chemical energy conversion (such as high product selectivity and atom economy) have been developed, and their interfacing with host materials has enabled recyclability, controlled site positioning, as well as access to fundamental insights into the catalytic mechanism and environment-governed selectivity. Among the wide variety of supports, metal-organic frameworks (MOFs) possess valuable characteristics (such as their porosity and versatility) that can influence the reaction environment and material architecture in a unique fashion. Here we highlight the various existing synthetic strategies to graft molecular complexes such as catalysts and photosensitizers onto MOFs for solar fuel production. The opportunities and limitations of one-pot and stepwise approaches are critically assessed, and the resulting materials are discussed based on their photocatalytic performances and the practical applicability of selected examples.
The design and fabrication of robust metallic states in graphene nanoribbons (GNRs) are challenging because lateral quantum confinement and many-electron interactions induce electronic band gaps when ...graphene is patterned at nanometer length scales. Recent developments in bottom-up synthesis have enabled the design and characterization of atomically precise GNRs, but strategies for realizing GNR metallicity have been elusive. Here we demonstrate a general technique for inducing metallicity in GNRs by inserting a symmetric superlattice of zero-energy modes into otherwise semiconducting GNRs. We verify the resulting metallicity using scanning tunneling spectroscopy as well as first-principles density-functional theory and tight-binding calculations. Our results reveal that the metallic bandwidth in GNRs can be tuned over a wide range by controlling the overlap of zero-mode wave functions through intentional sublattice symmetry breaking.
Citrullination of proteins, a post-translational conversion of arginine residues to citrulline, is recognized in rheumatoid arthritis, but largely undocumented in cancer. Here we show that ...citrullination of the extracellular matrix by cancer cell derived peptidylarginine deiminase 4 (PAD4) is essential for the growth of liver metastases from colorectal cancer (CRC). Using proteomics, we demonstrate that liver metastases exhibit higher levels of citrullination and PAD4 than unaffected liver, primary CRC or adjacent colonic mucosa. Functional significance for citrullination in metastatic growth is evident in murine models where inhibition of citrullination substantially reduces liver metastatic burden. Additionally, citrullination of a key matrix component collagen type I promotes greater adhesion and decreased migration of CRC cells along with increased expression of characteristic epithelial markers, suggesting a role for citrullination in promoting mesenchymal-to-epithelial transition and liver metastasis. Overall, our study reveals the potential for PAD4-dependant citrullination to drive the progression of CRC liver metastasis.
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