Rotary biomolecular machines rely on highly symmetric supramolecular structures with rotating units that operate within a densely packed frame of reference, stator, embedded within relatively rigid ...membranes. The most notable examples are the enzyme FoF1 ATP synthase and the bacterial flagellum, which undergo rotation in steps determined by the symmetries of their rotators and rotating units. Speculating that a precise control of rotational dynamics in rigid environments will be essential for the development of artificial molecular machines, we analyzed the relation between rotational symmetry order and equilibrium rotational dynamics in a set of crystalline molecular gyroscopes with rotators having axial symmetry that ranges from two- to fivefold. The site exchange frequency for these molecules in their closely related crystals at ambient temperature varies by several orders of magnitude, up to ca. 4.46 × 10 8 s −1 .
During B and T lymphocyte maturation, V(D)J recombination is initiated by creation of DNA double-strand breaks. Artemis is an exonuclease essential for their subsequent repair by nonhomologous ...end-joining. Mutations in DCLRE1C, the gene encoding Artemis, cause T
B
NK
severe combined immunodeficiency (ART-SCID) and also confer heightened sensitivity to ionizing radiation and alkylating chemotherapy. Although allogeneic hematopoietic cell transplantation can treat ART-SCID, conditioning regimens are poorly tolerated, leading to early mortality and/or late complications, including short stature, endocrinopathies, and dental aplasia. However, without alkylating chemotherapy as preconditioning, patients usually have graft rejection or limited T cell and no B cell recovery. Thus, addition of normal DCLRE1C cDNA to autologous hematopoietic stem cells is an attractive strategy to treat ART-SCID. We designed a self-inactivating lentivirus vector containing human Artemis cDNA under transcriptional regulation of the human endogenous Artemis promoter (AProArt). Fibroblasts from ART-SCID patients transduced with AProArt lentivirus showed correction of radiosensitivity. Mobilized peripheral blood CD34
cells from an ART-SCID patient as well as hematopoietic stem cells from Artemis-deficient mice demonstrated restored T and B cell development following AProArt transduction. Murine hematopoietic cells transduced with AProArt exhibited no increase in replating potential in an in vitro immortalization assay, and analysis of AProArt lentivirus insertions showed no predilection for sites that could activate oncogenes. These efficacy and safety findings support institution of a clinical trial of gene addition therapy for ART-SCID.
To explore the intersection of peer-to-peer milk sharing and donor milk banks.
A descriptive survey design containing closed and open-ended questions was used to examine women's perceptions of ...peer-to-peer milk sharing and milk banking. Closed-ended questions were analyzed using descriptive statistics and conventional qualitative content analysis was used to analyze open-ended responses.
Participants were recruited via the Facebook sites of two online milk-sharing networks (Human Milk 4 Human Babies and Eats on Feet).
Ninety-eight milk donors and 41 milk recipients who had donated or received breast milk in an arrangement that was facilitated via the Internet.
One half of donor recipients could not donate to a milk bank because there were no banks local to them or they did not qualify as donors. Other respondents did not donate to a milk bank because they viewed the process as difficult, had philosophical objections to milk banking, or had a philosophical attraction to peer sharing. Most donor respondents felt it was important to know the circumstances of their milk recipients. No recipient respondents had obtained milk from a milk bank; it was recognized that they would not qualify for banked milk or that banked milk was cost prohibitive.
Peer-to-peer milk donors and recipients may differ from milk bank donors and recipients in significant ways. Cooperation between milk banks and peer sharing networks could benefit both groups.
This essay summarizes deliberation by the Soil Science Society of America (SSSA) Ad Hoc Committee on Soil Quality (S-581) and was written to spur discussion among SSSA members. Varying perceptions of ...soil quality have emerged since the concept was suggested in the early 1990s, and dialogue among members is important because, unlike air and water quality, legislative standards for soil quality have not been and perhaps should not be defined. In simplest terms, soil quality is "the capacity (of soil) to function". This definition, based on function, reflects the living and dynamic nature of soil. Soil quality can be conceptualized as a three-legged stool, the function and balance of which requires an integration of three major components - sustained biological productivity, environmental quality, and plant and animal health. The concept attempts to balance multiple soil uses (e.g., for agricultural production, remediation of wastes, urban development, forest, range, or recreation) with goals for environmental quality. Assessing soil quality will require collaboration among all disciplines of science to examine and interpret their results in the context of land management strategies, interactions, and trade-offs. Society is demanding solutions from science. Simply measuring and reporting the response of an individual soil parameter to a given perturbation or management practice is no longer sufficient. The soil resource must be recognized as a dynamic living system that emerges through a unique balance and interaction of its biological, chemical, and physical components. We encourage SSSA members to consider the concept of soil quality (perhaps as a marketing tool) and to debate how it might enable us to more effectively meet the diverse natural resource needs and concerns of our rural, urban, and suburban clientele of today and tomorrow
The purification of hydroxycinnamic acids
-coumaric acid (
CA) and ferulic acid (FA) from grass cell walls requires high-cost processes. Feedstocks with increased levels of one hydroxycinnamate in ...preference to the other are therefore highly desirable. We identified and conducted expression analysis for nine BAHD acyltransferase
genes from sugarcane. The high conservation of AT10 proteins, together with their similar gene expression patterns, supported a similar role in distinct grasses. Overexpression of
in maize resulted in up to 75% increase in total
CA content. Mild hydrolysis and derivatization followed by reductive cleavage (DFRC) analysis showed that
CA increase was restricted to the hemicellulosic portion of the cell wall. Furthermore, total FA content was reduced up to 88%, resulting in a 10-fold increase in the
CA/FA ratio. Thus, we functionally characterized a sugarcane gene involved in
CA content on hemicelluloses and generated a C4 plant that is promising for valorizing
CA production in biorefineries.
Cellulosic Energy Cropping Systems presents a comprehensive overview of how cellulosic energy crops can be sustainably produced and converted to affordable energy through liquid fuels, heat and ...electricity. The book begins with an introduction to cellulosic feedstocks, discussing their potential as a large-scale sustainable energy source, and technologies for the production of liquid fuels, heat and electricity. Subsequent chapters examine miscanthus, switchgrass, sugarcane and energy cane, sorghums and crop residues, reviewing their phylogeny, cultural practices, and opportunities for genetic improvement. This is followed by a detailed focus on woody crops, including eucalyptus, pine, poplar and willow. Critical logistical issues associated with both herbaceous and woody feedstocks are reviewed, and alternate strategies for harvesting, transporting, and storing cellulosic materials are also examined. The final sectionof the booktackles the challenge of achieving long-term sustainability, addressing economic, environmental and social factors. Cellulosic Energy Cropping Systems is a valuable resource for academics, students and industry professionals working in the field of biomass cultivation and conversion, bioenergy, crop science and agriculture. Topics covered include: * Identifying suitable cellulosic energy crops that are adapted to a wide range of climates and soils * Best management practices for sustainably growing, harvesting, storing, transporting and pre-processing these crops * The development of integrated cellulosic energy cropping systems for supplying commercial processing plants * Challenges and opportunities for the long-term sustainability of cellulosic energy crops This book was conceived and initiated by David I. Bransby, Professor of Energy and Forage Crops in the Department of Crop, Soil and Environmental Sciences at Auburn University, USA. For more information on the Wiley Series in Renewable Resources, visit www.wiley.com/go/rrs
No-tillage (NT) practices for rainfed cereal production in semi-arid Mediterranean soils can conserve water and increase crop productivity, but producers are reluctant to adopt NT because of ...potential increases in penetration resistance and bulk density. We hypothesized that understanding soil quality could encourage NT adoption, but methods for selecting and assessing soil quality indicators needed to be developed for this region. Our objectives were to (1) identify the most sensitive indicators for evaluating long-term tillage and residue management within this region using factor analysis, and (2) compare soil quality assessment using those indicators with traditional evaluations using changes in water retention, earthworm activity and organic matter stratification ratio. Several soil physical, chemical, and biological indicators were measured within conventional tillage, minimum tillage, and NT (with and without stubble burning) treatments that represent a wide agro-climatic area in NE Spain. Sampling depth and management treatments significantly affected several indicators when evaluated individually and collectively. Principal component analysis identified three factors that accounted for 75 and 85% of the variation in soil measurements for 0–5- and 5–15-cm depth increments. Only two factors per depth showed significant differences among the four treatments. For both depth increments, one factor grouped soil physical attributes, and the other organic matter and biological properties. The indicators with the greatest loadings were identified as the most sensitive in each factor. These were penetration resistance, particulate organic matter (POM) and total organic matter within the 0–5
cm layer, and aggregate stability and POM within the 5–15-cm increment. Factor scores were positively correlated to soil water retention, earthworm activity and organic matter stratification, which were all greater in NT, regardless of stubble management. We conclude that (1) multivariate analyses are useful for selecting appropriate soil quality indicators, and (2) that adopting NT on Mediterranean semi-arid cropland can have several positive effects on soil quality within this region.
Nuclear spin is seen as a robust qubit. Electrons can be used to "read" to the nuclear state, but their presence causes decoherence. Researchers now show that this problem can be circumvented using a ...temporary spin state, thus enabling entanglement of the nuclear state at unprecedented speeds.
Crop residue has been identified as a near-term source of biomass for renewable fuel, heat, power, chemicals and other bio-materials. A prototype one-pass harvest system was used to collect residue ...samples from a corn (
Zea mays L.) field near Ames, IA. Four harvest scenarios (low cut, high-cut top, high-cut bottom, and normal cut) were evaluated and are expressed as collected stover harvest indices (CSHI). High-cut top and high-cut bottom samples were obtained from the same plot in separate operations. Chemical composition, dilute acid pretreatment response, ethanol conversion yield and efficiency, and thermochemical conversion for each scenario were determined. Mean grain yield in this study (10.1
Mg
ha
−1 dry weight) was representative of the average yield (10.0
Mg
ha
−1) for the area (Story County, IA) and year (2005). The four harvest scenarios removed 6.7, 4.9, 1.7, and 5.1
Mg
ha
−1 of dry matter, respectively, or 0.60 for low cut, 0.66 for normal cut, and 0.61 for the total high-cut (top+bottom) scenarios when expressed as CSHI values. The macro-nutrient replacement value for the normal harvest scenario was $57.36
ha
−1 or $11.27
Mg
−1. Harvesting stalk bottoms increased stover water content, risk of combine damage, estimated transportation costs, and left insufficient soil cover, while also producing a problematic feedstock. These preliminary results indicate harvesting stover (including the cobs) at a height of approximately 40
cm would be best for farmers and ethanol producers because of faster harvest speed and higher quality ethanol feedstock.
Intensive tillage, low‐residue crops, and a warm, humid climate have contributed to soil organic carbon (SOC) loss in the southeastern Coastal Plains region. Conservation (CnT) tillage and winter ...cover cropping are current management practices to rebuild SOC; however, there is sparse long‐term field data showing how these management practices perform under variable climate conditions. The objectives of this study were to use CQESTR, a process‐based C model, to simulate SOC in the top 15 cm of a loamy sand soil (fine‐loamy, kaolinitic, thermic Typic Kandiudult) under conventional (CvT) or CnT tillage to elucidate the impact of projected climate change and crop yields on SOC relative to management and recommend the best agriculture management to increase SOC. Conservation tillage was predicted to increase SOC by 0.10 to 0.64 Mg C ha−1 for six of eight crop rotations compared with CvT by 2033. The addition of a winter crop rye (Secale cereale L.) or winter wheat (Triticum aestivum L.) to a corn (Zea mays L.)–cotton (Gossypium hirsutum L.) or corn–soybean Glycine max (L.) Merr. rotation increased SOC by 1.47 to 2.55 Mg C ha−1. A continued increase in crop yields following historical trends could increase SOC by 0.28 Mg C ha−1, whereas climate change is unlikely to have a significant impact on SOC except in the corn–cotton or corn–soybean rotations where SOC decreased up to 0.15 Mg C ha−1 by 2033. The adoption of CnT and cover crop management with high‐residue‐producing corn will likely increase SOC accretion in loamy sand soils. Simulation results indicate that soil C saturation may be reached in high‐residue rotations, and increasing SOC deeper in the soil profile will be required for long‐term SOC accretion beyond 2030.
Core Ideas
High‐residue crop rotation in conservation tillage maximized SOC accumulation.
Cover crop and conservation tillage management would likely optimize SOC accretion.
Anticipated climate change was predicted to have a minimal impact on SOC by 2033.
Sorghum was not a viable option to replace corn in rotation for SOC accretion.
Alternative management was required for deep SOC accretion beyond 2033.
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