QTL for root angle and number in a population developed from bread wheats (Triticum aestivum) with contrasting adaptation to water-limited environments

Root architecture traits in wheat are important in deep soil moisture acquisition and may be used to improve adaptation to water-limited environments. The genetic architecture of two root traits, seminal root angle and seminal root number, were investigated using a doubled haploid population derived from SeriM82 and Hartog. Multiple novel quantitative trait loci (QTL) were identified, each one having a modest effect. For seminal root angle, four QTL (?log₁₀(P) >3) were identified on 2A, 3D, 6A and 6B, and two suggestive QTL (?log₁₀(P) >2) on 5D and 6B. For root number, two QTL were identified on 4A and 6A with four suggestive QTL on 1B, 3A, 3B and 4A. QTL for root angle and root number did not co-locate. Transgressive segregation was found for both traits. Known major height and phenology loci appear to have little effect on root angle and number. Presence or absence of the T1BL.1RS translocation did not significantly influence root angle. Broad sense heritability (h ²) was estimated as 50 % for root angle and 31 % for root number. Root angle QTL were found to be segregating between wheat cultivars adapted to the target production region indicating potential to select for root angle in breeding programs.     

Racial affective economies,disalienation and ‘race made ordinary’

This paper speaks against tolerance as an instrument of institutionalized anti-racism within academia where collegiality is a minimal expectation in interpersonal interactions. Through auto-ethnographic readings, the discussion focuses on the racial affective economies produced in universities as tolerance ‘makes race ordinary’. Within this reading, ‘making race ordinary’ is shown to produce unliveable lives because of its racial affective economies animated by contemptuous tolerance, disgust and disattendability. These negative affects emerge within the epistemology of ignorance produced by the racial contract and have affective and career consequences for racialized others placed outside of organizational networks. The paper argues that to destabilize the white power in networks that decide on access, tenure and promotion and to enable liveable lives within universities, the transformative potential of the transracial intimacy of friendship must be engaged. This entails ‘race made ordinary’ through disalienation-estrangement from the ‘raced’ subject positionings of the racial contract.     

The G-Protein Rab5A Activates VPS34 Complex II,a Class III PI3K,by a Dual Regulatory Mechanism

VPS34 complex II (VPS34CII) is a 386-kDa assembly of the lipid kinase subunit VPS34 and three regulatory subunits that altogether function as a prototypical class III phosphatidylinositol-3-kinase (PI3K). When the active VPS34CII complex is docked to the cytoplasmic surface of endosomal membranes, it phosphorylates its substrate lipid (phosphatidylinositol, PI) to generate the essential signaling lipid phosphatidylinositol-3-phosphate (PI3P). In turn, PI3P recruits an array of signaling proteins containing PI3P-specific targeting domains (including FYVE, PX, and PROPPINS) to the membrane surface, where they initiate key cell processes. In endocytosis and early endosome development, net VPS34CII-catalyzed PI3P production is greatly amplified by Rab5A, a small G protein of the Ras GTPase superfamily. Moreover, VPS34CII and Rab5A are each strongly linked to multiple human diseases. Thus, a molecular understanding of the mechanism by which Rab5A activates lipid kinase activity will have broad impacts in both signaling biology and medicine. Two general mechanistic models have been proposed for small G protein activation of PI3K lipid kinases. 1) In the membrane recruitment mechanism, G protein association increases the density of active kinase on the membrane. And 2) in the allosteric activation mechanism, G protein allosterically triggers an increase in the specific activity (turnover rate) of the membrane-bound kinase molecule. This study employs an in vitro single-molecule approach to elucidate the mechanism of GTP-Rab5A-associated VPS34CII kinase activation in a reconstituted GTP-Rab5A-VPS34CII-PI3P-PX signaling pathway on a target membrane surface. The findings reveal that both membrane recruitment and allosteric mechanisms make important contributions to the large increase in VPS34CII kinase activity and PI3P production triggered by membrane-anchored GTP-Rab5A. Notably, under near-physiological conditions in the absence of other activators, membrane-anchored GTP-Rab5A provides strong, virtually binary on-off switching and is required for VPS34CII membrane binding and PI3P production.     

Controllable microfluidic synthesis of multiphase drug‐carrying lipospheres for site‐targeted therapy

We report the production of micrometer‐sized gas‐filled lipospheres using digital (droplet‐based) microfluidics technology for chemotherapeutic drug delivery. Advantages of on‐chip synthesis include a monodisperse size distribution (polydispersity index (σ) values of <5%) with consistent stability and uniform drug loading. Photolithography techniques are applied to fabricate novel PDMS‐based microfluidic devices that feature a combined dual hydrodynamic flow‐focusing region and expanding nozzle geometry with a narrow orifice. Spherical vehicles are formed through flow‐focusing by the self‐assembly of phospholipids to a lipid layer around the gas core, followed by a shear‐induced break off at the orifice. The encapsulation of an extra oil layer between the outer lipid shell and inner bubble gaseous core allows the transport of highly hydrophobic and toxic drugs at high concentrations. Doxorubicin (Dox) entrapment is estimated at 15 mg mL^?1 of particles packed in a single ordered layer. In addition, the attachment of targeting ligands to the lipid shell allows for direct vehicle binding to cancer cells. Preliminary acoustic studies of these monodisperse gas lipospheres reveal a highly uniform echo correlation of greater than 95%. The potential exists for localized drug concentration and release with ultrasound energy. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009