tRNA-guanine transglycosylase from Escherichia coli: Recognition of dimeric, unmodified tRNATyr

In order to probe the interaction between tRNA and the tRNA hypermodifying enzyme, tRNA-guanine transglycosylase (TGT) from Escherichia coli, we have undertaken the generation of E coli tRNATyr and analogues. During efforts to adapt currently available in vitro transcription techniques we encountered difficulties attributable to dimerization of the tRNA products. E coli tRNATyr has previously been characterized for its ability to form a dimer in solutions of suitable salt concentrations at appropriate temperatures (Yang SK, Soll DG, Crothers DM (1972) Biochemistry 11, 2311-2320; Rordorff BF, Kearns DR (1976) Biochemistry 15, 3320-3330). We have applied similar techniques to our unmodified analogue of E coli tRNATyr and produced both monomeric and dimeric forms of E coli tRNATyr. In this report we find that the dimer does serve as a substrate for modification by TGT. While both the conformers are equal in terms of Vmax (within experimental error) a 2.5-fold increase in KM occurs when going from monomer to dimer. This suggests that TGT prefcrentially binds the monomer but once either conformer is bound will catalyze the modification reaction equally well. We have also compared the results for the two conformers to our previous data of an RNA minihelix corresponding to the anticodon arm of E coli tRNATyr. Here we find that our earlier conclusion, that the recognition elements for TGT are localized within the anticodon arm of cognate tRNAs, is supported.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31951/1/0000904.pd

Professional Occupations, Knowledge-Driven Firms, And Entrepreneurship: A National And Regional Analysis

The worldwide dominance of Western nations in commercial knowledge-intensive services has declined between 1995 and 2010, but the slippage in revenue was only from 88 to 79 percent. The European Union and North America remain the two largest regions in consumption and in exporting. Four professional service sectors—accounting, law, engineering, and management consultancy—have shown stability or even growth in the past decade. Entry and expansion requirements in these fields, at home and abroad, constitute barriers for both individual professionals and companies. Entrepreneurship is evident in these sectors, as small and medium size enterprises have maintained their viability against large firms. Only accountancy shows a high degree of concentration, but competition in this sector, too, is expected from the emerging economies, especially China. Professional service firms of the West have forged strong linkages with both domestic and foreign clients via relationship marketing. Technology is an important factor via automation. Although each of the four sectors is facing both external and internal challenges, they continue to grow and appear to be meeting the challenges in part by more innovation and transparency

Comparative effect of ALA derivatives on protoporphyrin IX production in human and rat skin organ cultures

Samples of human and rat skin in short-term organ culture exposed to ALA or a range of hydrophobic derivatives were examined for their effect on the accumulation of protoporphyrin IX (PpIX) measured using fluorescence spectroscopy. With the exception of carbobenzoyloxy-D-phenylalanyl-5-ALA-ethyl ester the data presented indicate that, in normal tissues, ALA derivatives generate protoporphyrin IX more slowly than ALA, suggesting that they are less rapidly taken up and/or converted to free ALA. However, the resultant depot effect may lead to the enhanced accumulation of porphyrin over long exposure periods, particularly in the case of ALA-methyl ester or ALA-hexyl ester, depending on the applied concentration and the exposed tissue. Addition of the iron chelator, CP94, greatly increased PpIX accumulation in human skin exposed to ALA, ALA-methyl ester and ALA-hexyl ester. The effect in rat skin was less marked.</p

SF3B1 hotspot mutations confer sensitivity to PARP inhibition by eliciting a defective replication stress response.

SF3B1 hotspot mutations are associated with a poor prognosis in several tumor types and lead to global disruption of canonical splicing. Through synthetic lethal drug screens, we identify that SF3B1 mutant (SF3B1MUT) cells are selectively sensitive to poly (ADP-ribose) polymerase inhibitors (PARPi), independent of hotspot mutation and tumor site. SF3B1MUT cells display a defective response to PARPi-induced replication stress that occurs via downregulation of the cyclin-dependent kinase 2 interacting protein (CINP), leading to increased replication fork origin firing and loss of phosphorylated CHK1 (pCHK1; S317) induction. This results in subsequent failure to resolve DNA replication intermediates and G2/M cell cycle arrest. These defects are rescued through CINP overexpression, or further targeted by a combination of ataxia-telangiectasia mutated and PARP inhibition. In vivo, PARPi produce profound antitumor effects in multiple SF3B1MUT cancer models and eliminate distant metastases. These data provide the rationale for testing the clinical efficacy of PARPi in a biomarker-driven, homologous recombination proficient, patient population

Crop Updates 2002 - Oilseeds

This session covers twenty seven papers from different authors: 1. Forward and acknowledgements, Dave Eksteen, ACTING MANAGER OILSEEDS PRODUCTIVITY AND INDUSTRY DEVELOPMENT Department of Agriculture PLENARY SESSION 2. GMO canola - Track record in Canada, K. Neil Harker and George W. Clayton,Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, Alberta, R. Keith Downey, Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan 3. GMO canola – Prospects in Western Australia farming systems, Keith Alcock, Crop Improvement Institute, Department of Agriculture 4. Diamondback moth (DBM) in canola, Kevin Walden, Department of Agriculture CANOLA AGRONOMY 5. Getting the best out of canola in the low rainfall central wheatbelt, Bevan Addison and Peter Carlton, Elders Ltd 6. Canola variety performance in Western Australia, Kevin Morthorpe, Stephen Addenbrooke and Alex Ford, Pioneer Hi-Bred Australia P/L 7. Relative performance of new canola varieties in Department of Agriculture variety trials in 2000 and 2001, S. Hasan Zaheer, GSARI, Department of Agriculture, G. Walton, Crop Improvement Institute, Department of Agriculture 8. Which canola cultivar should I sow? Imma Farré, CSIRO Plant Industry, Floreat, Bill Bowden,Western Australia Department of Agriculture 9. The effect of seed generation and seed source on yield and quality of canola, Paul Carmody, Department of Agriculture 10. The accumulation of oil in Brassica species, J.A. Fortescue and D.W. Turner, Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, B. Tan, PO Box 1249, South Perth 11. Potential and performance of alternative oilseeds in WA, Margaret C. Campbell, Centre for Legumes in Mediterranean Agriculture 12. Comparison of oilseed crops in WA, Ian Pritchard and Paul Carmody, Department of Agriculture, Centre for Cropping Systems, Margaret Campbell, Centre for Legumes in Mediterranean Agriculture 13. Identifying constraints to canola production, Dave Eksteen, Canola Development Officer, Department of Agriculture 14. Boron – should we be worried about it? Richard W. BellA, K. FrostA, Mike WongB, and Ross BrennanC , ASchool of Environmental Science, Murdoch University, BCSIRO Land and Water, CDepartment of Agriculture PEST AND DISEASE 15. Yield losses caused when Beet Western Yellows Virus infects canola, Roger Jones and Jenny Hawkes, Department of Agriculture, and Centre for Legumes in Mediterranean Agriculture 16. Influence of climate on aphid outbreaks and virus epidemics in canola, Debbie Thackray, Jenny Hawkes and Roger Jones, Centre for Legumes in Mediterranean Agriculture and Department of Agriculture 17. The annual shower of blackleg ascospores in canola: Can we predict and avoid it? Moin U. Salam, Ravjit K. Khangura, Art J. Diggle and Martin J. Barbetti, Department of Agriculture 18. Environmental influences on production and release of ascospores of blackleg and their implications in blackleg management in canola, Ravjit K. Khangura, Martin J. Barbetti , Moin U. Salam and Art J. Diggle, Department of Agriculture 19. WA blackleg resistance ratings on canola varieties form 2002, Ravjit Khangura, Martin J. Barbetti and Graham Walton, Department of Agriculture 20. Bronzed field beetle management in canola, Phil Michael, Department of Agriculture 21. DBM control in canola: Aerial versus boom application, Paul Carmody, Department of Agriculture 22. Effect of single or multiple spray trearments on the control of Diamondback moth (Plutella xylostella) and yield of canola at Wongan Hills, Françoise Berlandier, Paul Carmody and Christiaan Valentine, Department of Agriculture ESTABLISHMENT 23. GrainGuardÔ - A biosecurity plan for the canola industry, Greg Shea, Department of Agriculture 24. Large canola seed is best, particularly for deep sowing, Glen Riethmuller, Rafiul Alam, Greg Hamilton and Jo Hawksley, Department of Agriculture 25. Canola establishment with seed size, tines and discs, with and without stubble, Glen Riethmuller, Rafiul Alam, Greg Hamilton and Jo Hawksley, Department of Agriculture WEEDS 26. Role of Roundup ReadyÒ canola in the farming system, Art Diggle1, Patrick Smith2, Paul Neve3, Felicity Flugge4, Amir Abadi5, Stephen Powles3 1Department of Agriculture, 2CSIRO, Sustainable Ecosystems, 3Western Australian Herbicide Resistance Initiative, University of Western Australia, 4Centre for Legumes in Mediterranean Agriculture, University of Western Australia, 5Touchstone Consulting, Mt Hawthorn FEED 27. Getting value from canola meals in the animal feed industries: Aquaculture, Brett Glencross and John Curnow, Department of Fisheries - Government of Western Australia and Wayne Hawkins, Department of Agricultur

CXCR3 Antagonism of SDF-1(5-67) Restores Trabecular Function and Prevents Retinal Neurodegeneration in a Rat Model of Ocular Hypertension

Glaucoma, the most common cause of irreversible blindness, is a neuropathy commonly initiated by pathological ocular hypertension due to unknown mechanisms of trabecular meshwork degeneration. Current antiglaucoma therapy does not target the causal trabecular pathology, which may explain why treatment failure is often observed. Here we show that the chemokine CXCL12, its truncated form SDF-1(5-67), and the receptors CXCR4 and CXCR3 are expressed in human glaucomatous trabecular tissue and a human trabecular cell line. SDF-1(5-67) is produced under the control of matrix metallo-proteinases, TNF-α, and TGF-β2, factors known to be involved in glaucoma. CXCL12 protects in vitro trabecular cells from apoptotic death via CXCR4 whereas SDF-1(5-67) induces apoptosis through CXCR3 and caspase activation. Ocular administration of SDF-1(5-67) in the rat increases intraocular pressure. In contrast, administration of a selective CXCR3 antagonist in a rat model of ocular hypertension decreases intraocular pressure, prevents retinal neurodegeneration, and preserves visual function. The protective effect of CXCR3 antagonism is related to restoration of the trabecular function. These data demonstrate that proteolytic cleavage of CXCL12 is involved in trabecular pathophysiology, and that local administration of a selective CXCR3 antagonist may be a beneficial therapeutic strategy for treating ocular hypertension and subsequent retinal degeneration

Using Pre-existing Microarray Datasets to Increase Experimental Power: Application to Insulin Resistance

Although they have become a widely used experimental technique for identifying differentially expressed (DE) genes, DNA microarrays are notorious for generating noisy data. A common strategy for mitigating the effects of noise is to perform many experimental replicates. This approach is often costly and sometimes impossible given limited resources; thus, analytical methods are needed which increase accuracy at no additional cost. One inexpensive source of microarray replicates comes from prior work: to date, data from hundreds of thousands of microarray experiments are in the public domain. Although these data assay a wide range of conditions, they cannot be used directly to inform any particular experiment and are thus ignored by most DE gene methods. We present the SVD Augmented Gene expression Analysis Tool (SAGAT), a mathematically principled, data-driven approach for identifying DE genes. SAGAT increases the power of a microarray experiment by using observed coexpression relationships from publicly available microarray datasets to reduce uncertainty in individual genes' expression measurements. We tested the method on three well-replicated human microarray datasets and demonstrate that use of SAGAT increased effective sample sizes by as many as 2.72 arrays. We applied SAGAT to unpublished data from a microarray study investigating transcriptional responses to insulin resistance, resulting in a 50% increase in the number of significant genes detected. We evaluated 11 (58%) of these genes experimentally using qPCR, confirming the directions of expression change for all 11 and statistical significance for three. Use of SAGAT revealed coherent biological changes in three pathways: inflammation, differentiation, and fatty acid synthesis, furthering our molecular understanding of a type 2 diabetes risk factor. We envision SAGAT as a means to maximize the potential for biological discovery from subtle transcriptional responses, and we provide it as a freely available software package that is immediately applicable to any human microarray study