ALBERT

Description: The U.S. Department of Energy has mandated the production of 16 billion gallons (60.6 billion liters) of renewable biofuel from cellulosic feedstocks by 2022. The perennial grass, Miscanthus x giganteus , is a potential candidate for cellulosic biofuel production because of high productivity with minimal inputs. This study determined the effect of three different spring fertilizer treatments (0, 60, and 120 kg N ha −1 yr −1 as urea) on biomass production, soil organic matter (SOM), and inorganic N leaching in Illinois, Kentucky, Nebraska, New Jersey, and Virginia, along with N 2 O and CO 2 emissions at the IL site. There were no significant yield responses to fertilizer treatments, except at the IL site in 2012 (yields in 2012, year 4, varied from 10 to 23.7 Mg ha −1 across all sites). Potentially mineralizable N increased across all fertilizer treatments and sites in the 0 – 10 cm soil depth. An increase in permanganate oxidizable carbon (POX-C, labile C) in surface soils occurred at the IL and NJ sites, which were regularly tilled before planting. Decreases in POX-C were observed in the 0 – 10 cm soil depth at the KY and NE sites where highly managed turfgrass was grown prior to planting. Growing M . x giganteus altered SOM composition in only four years of production by increasing the amount of potentially mineralizable N at every site, regardless of fertilization amount. Nitrogen applications increased N leaching and N 2 O emission without increasing biomass production. This suggests that for the initial period (4 yr) of M . x giganteus production, N application has a detrimental environmental impact without any yield benefits and thus should not be recommended. Further research is needed to define a time when N application to M . x giganteus results in increased biomass production. This article is protected by copyright. All rights reserved.

Description: ABSTRACT Sand ramps have the potential to provide rich palaeoenvironmental information in dryland regions wherein proxy records are typically scarce. However, current knowledge of the geomorphic controls and processes of sand ramp formation is limited. This study provides a data-rich examination of the key factors controlling sand ramp formation. The location and morphology of 75 sand ramps in southern Namibia are examined. The sediments and chronologies of 10 sand ramps are studied in detail using 51 OSL dates and 83 grain-size and LOI samples. Heavy mineral assemblages are used to determine the provenance of 10 samples and OSL sensitivity is used to explore geomorphic processes of 8 samples. Sand ramp morphology can be grouped into one of four classes of increasing size and complexity and is closely linked to the available accommodation space. Heavy mineral assemblages indicate local sediment sources and all 75 studied sand ramps are within 4 km of a large ephemeral river channel or within 5.5 km of a dune field. Therefore, accommodation space and sediment supply are identified as the primary controls of sand ramp formation. Sedimentology and OSL sensitivity suggest a complex interplay of aeolian, fluvial and colluvial processes contribute to sand ramp formation with large variability observed between ramps. Three of the ten dated sand ramps have been present in the Namibian landscape for 〉100 ka. Eight sand ramps show episodic deposition between 〉75-12 ka and five show evidence of surface reworking over the past 2 ka. Environmental sensitivity is likely to be linked to the size and availability of the accommodation space. Therefore, individual sand ramps are expected to reflect local environmental conditions, recording when an abundant sediment supply coincided with available accommodation space, whilst a regional analysis of multiple sand ramps with chronometric data offers the potential to identify larger scale palaeoenvironmental controls of sediment supply.

Description: Abstract 2011 Although both talin and kindlin-3 binding to the β3 cytoplasmic domain are required for agonist-induced αIIbβ3 activation in platelets, the biochemical basis for this dual requirement is not clear. Recent NMR and hydrogen-deuterium exchange studies of disulfide-stabilized complexes containing the full cytoplasmic domains of αIIb and β3 dispersed in detergent micelles or lipid bilayers revealed that the β3 cytoplasmic domain consists of three helices: a stable proximal helix contiguous with the transmembrane domain and two distal dynamic amphiphilic helices whose fluctuations allow interaction of the helices with lipid bilayers or cytoplasmic proteins. These results suggest a cooperative model for talin and kindlin-3 binding to β3 with the talin and kindlin-3 binding sites kinetically- and thermodynamically-linked. Whether there is a preferred temporal sequence for kindlin-3 versus talin binding to β3 during physiological αIIbβ3 activation in platelets is not known, but the greater mobility of the kindlin-3 binding site suggests it might have a kinetic advantage over talin, assuming both are present in appropriate forms for binding. Much is known about the structure and function of talin, but substantially less is known about kindlin-3 in part because it has not been possible to express the complete molecule in bacterial expression systems. To address this issue, we have examined kindlin-3 expression and function in human platelets. Two kindlin-3 isoforms have been identified, a long form (Mr ∼ 76 kDa; accession: NM_178443) and a short form (Mr ∼75 kDa accession: NM_031471), that differ by the presence of 4 residues (RIPR; residues 360–363) in the PH domain of the long isoform. Using highly purified platelet and leukocyte RNA and RT PCR, we found that kindlin-3 expressed in platelets and leukocytes consist almost entirely of the 663 amino acid short isoform. Kindlin-3 present in platelet extracts is functionally active and spontaneously binds to the β3 cytoplasmic domain in pull down assays. Moreover, because kindlin-3 binding is abrogated by the β3 mutations S752P and T759A, but not T759F, the in vitro binding of kindlin-3 does not appear to be phosphorylation dependent. Further, surface plasmon resonance spectroscopy suggests that the PH domain of kindlin-3 partially drives membrane binding in the presence of phospholipids. Treatment of washed human platelets with the PAR1-activating peptide TRAP-6 (SFLLRNP) resulted in the rapid incorporation of kindlin-3 present in the platelet cytosol into the platelet cytoskeleton. We also found that kindlin-3 is present in dense fractions when platelets extracts were fractionated on sucrose gradients. Likewise, immunofluorescent images of platelets adherent to fibrinogen and platelet immuno-electron microscopy detected the presence of kindlin-3 in vesicular structures. Finally, using out-dated human platelets as starting material, we purified kindlin-3 to near homogeneity by the sequential use of ion-exchange and gel-filtration chromatography. These results provide a foundation for understanding the unique role that kindlin-3 plays in regulating the activity of platelet αIIbβ3. Disclosures: No relevant conflicts of interest to declare.