Plant Selection for Bioretention Systems and Stormwater Treatment Practices

Landscape/Regional and Urban Planning; Water Quality/Water Pollution; Hydrology/Water Resources; Urban Ecolog

Novel screens to identify genes regulating global chromatin structure during female meiotic prophase

During female meiotic prophase in many organisms, a specialized chromatin structure is formed in the oocyte nucleus. This structure is known as the karyosome, and has been proposed to be important for the formation of the female meiotic bipolar spindle. However, how the karyosome is formed and maintained is not very well understood. To identify proteins involved in the formation and maintenance of the karyosome, I carried out a cytological screen on a collection of 220 mutant fly lines for mutants that were defective in karyosome morphology. The screen identified 46 mutants on the X and 2nd chromosome with abnormal karyosomes. Genetic analysis of these 46 mutants, followed by molecular analysis of one mutant, identified SRPK (SR Protein Kinase) as a protein that is important for the proper formation of the karyosome. NHK-1 (Nucleosomal Histone Kinase 1) was previously identified as a protein that is essential for the formation of the karyosome via its phosphorylation of BAF (Barrier-to-Autointegration Factor). NHK-1 phosphorylation of BAF leads to the release of chromatin from the nuclear membrane, an essential step for the formation of the karyosome, however, the regulation of this process is unclear. In order to identify genes that interact with NHK-1, I carried out a genetic modifier screen using a semi-lethal allele of NHK-1, NHK-1trip. After screening a collection of 44 deficiencies located on the 2nd chromosome, I identified a genetic region (44B8-44D1) containing a gene that interacts with NHK-1 and, when gene dosage is halved, enhanced the semi-lethal phenotype of NHK-1trip

Plant Selection for Bioretention Systems and Stormwater Treatment Practices

Landscape/Regional and Urban Planning; Water Quality/Water Pollution; Hydrology/Water Resources; Urban Ecolog

Issues and Challenges of Corporate Change Initiatives in Singapore's Small Business Sector

This paper1 explores the change propensity of owners of small and medium-sized enterprises (SMEs) and associated challenges in the Republic of Singapore. Based on both qualitative interviews and quantitative survey research amongst Singapore's SME owners and change advocates, it identifies several critical issues with regard to the successful management of organizational transitions in small firms: "the need to change", "the mindset of small entrepreneurs", "change management know how" and "the value of external consultancy inputs". The data suggest that awareness building measures and educational efforts are necessary to enable more owners of local SMEs to benefit from change management tools and concepts as well as respective external expertise. Change management training and exposure to "best" (sectoral) change management practices and successful projects facilitated by external change agents might help more small entrepreneurs to manage both intra-organizationally and externally induced organizational changes more effectively

INVESTIGATING CATALYST DESIGN STRATEGIES FOR SELECTIVE REACTION OF CYCLIC C4 OXYGENATES FROM BIOMASS

Numerous studies have shown that the properties of metal catalysts can in principle be fine-tuned by controlling the composition of the metal surface with high precision. The ability to design catalysts capable of high selectivity towards the conversion of a single functional group in a multifunctional molecule is a major objective for heterogeneous catalysis research. This need for high selectivity toward a single functional group is of growing importance in efforts to improve biorefining operations, where biomass-derived multifunctional carbohydrates are key building block intermediates that must be converted to a vast range of commodity chemical products such as fuels, pharmaceuticals, food products, and more. This work focuses on results from high resolution electron energy loss spectroscopy (HREELS) and temperature programmed desorption (TPD) experiments combined with selective use of density functional theory (DFT) calculations on single-crystal surfaces under ultrahigh vacuum conditions to study structure-property relations for a series of C4 cyclic oxygenates on catalytic metal surfaces. The objective of this work is to identify methods to tailor surfaces that are able to selectively catalyze conversions of one functional group in the multifunctional molecule. Two types of cyclic probe molecules have been studied in particular: 3-membered epoxide rings (in which ring-strain is high and the character of the oxygenate function is therefore more reactive) and 5-membered furanone rings (in which the ring is relatively stable). Both the epoxides and furanones contain an unsaturated C=C bond; for many biorefining applications it is desirable to selectively hydrogenate the olefin while keeping the oxygenate functionality intact. In this contribution, we explore the role of surface structure and composition in dictating the reaction pathways for multifunctional C4 cyclic oxygenates on key transition metal and bimetallic surfaces. Results for the epoxide probe molecule studies indicate differing modes of interaction with different metal surfaces. On a platinum or palladium surface, the epoxide ring opens irreversibly while the C=C functional group has a strong interaction with the surface. However, on a silver surface, the epoxide ring also opens, but can be made to close reversibly. An effective catalyst design strategy, then, is to combine silver on a predominantly platinum or palladium surface in order to create a bimetallic catalyst with high selectivity toward reaction of the olefin while keeping the epoxide ring intact. Recent studies of the chemistry of furanone species indicate that the olefin group interacts strongly with a platinum or palladium metal surface, and therefore is very likely to also determine how the molecule reacts. In this presentation, relationships between catalyst design strategies for epoxides versus furanones will be discussed, as will the likely biorefining reactions that such strategies can impact

Structure restraints from heteronuclear pseudocontact shifts generated by lanthanide tags at two different sites

Pseudocontact shifts (PCS) encode long-range information on 3D structures of protein backbones and side-chains. The level of structural detail that can be obtained increases with the number of different sites tagged with a paramagnetic metal ion to generate PCSs. Here we show that PCSs from two different sites can suffice to determine the structure of polypeptide chains and their location and orientation relative to the magnetic susceptibility tensor χ, provided that PCSs are available for 1H as well as heteronuclear spins. In addition, PCSs from two different sites are shown to provide detailed structural information on the conformation of methyl group-bearing amino-acid side-chains. A previously published ensemble structure of ubiquitin is shown to explain the magnetic susceptibility and alignment tensors slightly better than structures that try to explain the experimental data by a single conformation, illustrating the potential of PCSs as a tool to investigate small conformational changes.Financial support by the Australian Research Council is gratefully acknowledged