1,250 research outputs found
The generation of oxygen radicals during host plant responses to infection
Recent evidence points to significant oxygen radical production by some plant tissues in response to pathogenic challenge. These findings have proved quite controversial, in part because of an inadequate appreciation of the behaviour of oxygen radicals in biological systems. This review critically discusses the evidence to date and outlines several potential roles for oxygen species in host-pathogen interactions. The production of oxygen radicals during plant defence responses is compared to the respiratory burst of mammalian phagocytic cells
Open Source or Off-the-Shelf?:Establishing an institutional repository for a small institution
Effective management of digital assets as well as increasing research exposure and impact are particular challenges faced by smaller institutions with limited infrastructure and resources. The paper explores the significant factors involved in considering, planning and establishing an institutional repository for Bond University, one of the smaller higher education providers in Australia. The salient benefits and advantages as well as the disadvantages of implementing an off-the-shelf product as opposed to an open source solution for an institutional repository are compared. The rationale for choosing a proprietary product over an open source solution is discussed, as well as the process for obtaining funding and the support of key stakeholders within the University. The paper describes the strategies employed to populate the repository retrospectively and to train academic staff and researchers in self-archiving. The development of policy governing the repository and intellectual property and copyright implications are also covered. Background on Bond Universit
One-pot multi-reaction processes: synthesis of natural products and drug-like scaffolds
One-pot multi-reaction processes involving Overman rearrangements, metathesis cyclizations, and Diels–Alder reactions have been developed for the rapid and efficient synthesis of amino-substituted carbocyclic and heterocyclic compounds. This account describes the development and optimization of these processes, as well as their applications in the synthesis of natural products and drug-like scaffolds
Helium and Nitrogen Enrichment in Massive Main Sequence Stars: Mechanisms and Implications for the Origin of WNL Stars
The evolutionary paths taken by massive stars with remain substantially uncertain. They begin their lives as
main sequence (MS) O-stars. Depending on their masses, rotation rates, and
metallicities, they can then encounter a wide range of evolutionary states with
an equally broad set of possible surface compositions and spectral
classifications. We present a new grid of calculations for the evolution of
such stars that covers a broad range in mass, M/M to ,
rotation rate, to , metallicity,
to , and -element enhancement,
to . We show that rotating stars undergo
rotationally-induced dredge-up of nucleosynthetic products, mostly He and N, to
their surfaces while still on the MS. Non-rotating metal-rich stars also reveal
the products of nucleosynthesis on their surfaces because even modest amounts
of mass loss expose their "fossil" convective cores: regions that are no longer
convective, but which were part of the convective core at an early stage in the
star's evolution. Thus surface enhancement of He and N is expected for rotating
stars at all metallicities, and for non-rotating stars if they are relatively
metal-rich. We calculate a stellar atmosphere for a representative model from
our grid, properly accounting for He- and N-enhancement, and show that the
resulting spectrum provides a good match to observed WNL stars, strongly
suggesting that the physical mechanisms we have identified are the ultimate
cause of the WNL phase.Comment: 21 pages, 18 figures, 2 tables, accepted for publication in MNRAS, in
pres
The crown rot ‘deadhead’ phenomenon in durum wheat
[INTRODUCTION]
Crown rot of wheat, caused by Fusarium pseudograminearum (Fp), is a serious disease threat across the Australian wheat belt, particularly in durum wheat. Control of this disease is primarily based on crop rotations and reducing inoculum, with a continued goal of producing crops with increased resistance. Plant reactions to disease are typically described using stem browning, sometimes coinciding with the production of ‘deadheads’, or stems undergoing premature senescence due to infection.
The mechanism by which crown rot causes yield loss has not yet been clearly described, however evidence is emerging indicating fungal blockage of both xylem and phloem tissues (1). It would be logical to infer that ‘deadhead’ stems had more Fp biomass and greater vascular tissue colonisation, resulting in their premature death. It must, however, be demonstrated. The information gained by examining ‘deadheads’ may be applied to less extreme infections as an explanation for the physiological effects behind crown rot associated yield loss.
The idea behind this experiment was to investigate the levels of colonisation of stems of durum plants exhibiting ‘deadheads’ in the field and compare these to stems of the same plants which were still living. Microscopic assessment of stem sections is also planned
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