99 research outputs found

    The response of wheat genotypes to inoculation with Azospirillum brasilense

    Get PDF
    It is well documented in many studies that plant growth promoting rhizobacteria (PGPR) are capable of increasing plant growth and productivity in a range of agricultural crops, reducing dependence on chemical amendments and maintaining a safe environment. Over the last two decades PGPR inoculants have been increasingly used in agriculture to improve crop productivity and farming system sustainability. Such eco-friendly technologies are needed to address sustainable food security and to avoid global dependence on hazardous agricultural chemicals which ultimately destabilize agro-ecosystems. The nitrogen fixing bacteria, Azospirillum brasilense, has been an important PGPB (plant growth promoting bacteria) used to enhance the growth and yield of many crops globally. This is attributed mainly to its ability to produce phytohormones. While much is known about A. brasilense, the promising effect of PGPBs in general in the field is limited by factors that influence their survival and activity in the rhizosphere. The attachment of bacteria to roots is an essential and necessary condition for the establishment of an effective association. This association is dependent upon the population density of active PGPB cells in the rhizosphere which are able to compete with indigenous bacteria. However, how survival and persistence of inoculant bacteria in the rhizosphere, the effect of inoculum on the rhizosphere community, in particular the nitrogen fixing community, and the effect of plant genotype contributes to plant growth promotion by Azospirillum in the field have not been widely studied. Better understanding of the plant x inoculum interaction requires determining if there is an effect of plant genotype and monitoring and estimation of the persistence of PGPB in the rhizosphere. The overall aim of this project was to examine the effect of the wheat (Triticum aestivum) genotype x Azospirillum interaction on colonization of roots and plant growth promotion. These effects were studied under both controlled hydroponic conditions in the laboratory and in the field. Plant growth parameters and bacterial colonization of the rhizosphere were determined in both conditions. Differences in root characteristics of twenty three diverse wheat genotypes were observed after growth in the hydroponic system; however responses to inoculation with A. brasilense Sp7 and Sp7-S were variable. In some cases growth parameters were increased and in others they were decreased. There was an apparent increase in responsiveness to inoculation with azospirilla by synthetically derived genotypes observed in root length measurements but otherwise there was no trend according to the genetic source of wheat. Microscopic observations confirmed the different root colonisation patterns by Sp7 and Sp7-S. However, colonisation pattern was not influenced by plant genotype. Relationships between shoot dry weight and root growth parameters were positive as expected but were strengthened with inoculation

    Using local and historical data to enhance understanding of spatial and temporal rainfall patterns

    Get PDF
    Farmers face uncertainty in their businesses from many factors, but rainfall is a key determinant of both the nature of the production system and variation in financial returns. Currently, various weather forecasting services are available from the Australian Bureau of Meteorology (BoM) based on about 7000 stations covering all of Australia. Seasonal Climate Forecasts are seen as another tool that can help to improve farm productivity. It is well known that many farmers keep their own rainfall records, and likely that the farmers have a high degree of confidence in their own records. Australian Bureau of Statistics figures indicate that there were possibly 7000 grain related ‘agricultural businesses’ in NSW alone in 2009/10 indicating that there is the potential to increase data density by up to an order of magnitude. This project is part of a broader study to improve rainfall predictions for grain farmers using data collected locally to the users (crowd sourcing). The data is collected directly on farm, and from other sources which may be available. The focus is on the historical data, its collection and analysis, in terms of discerning patterns in time and space which may help provide a local framework, within which coarser scale forecasts can be interpreted and understood. Data will be stored on secure database systems at the University of Sydney. Results indicate that farm data does provide more local detail, temporally and spatially. Deficit and surplus analysis demonstrates the predictive capacity of the local temporal data, despite limited data precluding the definition of ideal criteria and parameters for predictive ‘similar year’ selection. The spatial data demonstrates quantifiable site specific differences from institutional data. Testing across more climate types may allow these differences to be defined within and across regions. Tests for an indicator time period show that farm rainfall in the early part of the growing season (April and May) may indeed be indicative of seasonal condtions, while more data is needed to confirm this. The use of southern oscillation life cycle information to select appropriate years considerably improved the relationships revealed, with a doubling of relationship strength across all climatic types, although the strength of the relationships differed across the climatic types, and the strongest relationships were split between the months of April and May. More extensive analysis, with more data across more BoM districts (and therefore climate classes) will be required to confirm this conclusion, but it appears that farm rainfall records and SOI information can provide an indicator time period to help farmers interpret, refine and utilise seasonal forecasts

    Out of the darkness: A History of Huntington's Disease in Australia

    Get PDF
    Huntington’s disease (HD) is a genetic neurological condition which has a profound influence on the families it affects. The symptoms of the disease are challenging – in addition, social forces strongly influence the way the disease is experienced. It has been a deeply stigmatised condition, and its presence was often kept secret. In this dissertation, I have explored both social and medical aspects of the history of HD, primarily in Australia, building on the work of two scholars, Peter Harper (UK) and Alice Wexler (US). By tracing the histories of HD families, I discovered that HD has been part of the fabric of life in Australia since the convict era, and that some families with the disease were well-respected in their communities, in contrast to narratives which have presented the stigma as inevitable. Wexler has previously shown that in the US, the degree of stigma faced by HD families has varied over time, and my research found this to be also true of the disease in Australia. The earliest descriptions of the disease in the US were mostly made by physicians familiar with HD families. My research revealed a similar story - two physicians who published on HD both grew up in an area of Tasmania with relatively high rates of the disease. The impact of eugenic thinking in the stigmatization of HD in the US, Germany and the UK was noted more than 20 years ago, though its impact in other countries has remained unexplored. Eugenics as a formal movement was not successful in Australia, however eugenic ideas formed part of the social discourse. I show through medical journal articles, items in the popular press and educational organisations how those with hereditary diseases were labeled as “unfit”, promoting stigma which contributed to it being hidden. Finally I describe how the disease began to emerge from “the closet” in the early 1970s, with families and researchers forging a new collaboration to search for treatments, support families and reduce stigma

    The role of purified antibodies and antibody fragments in the enhancement and the acute destruction of mouse allografts

    Get PDF
    Contains fulltext : mmubn000001_02657666x.pdf (publisher's version ) (Open Access)Promotores : R. Koene en H. Bloemers117 p

    Differences between the pathogenesis of senile plaques and congophilic angiopathy in Alzheimer disease

    Get PDF
    Contains fulltext : 25633___.PDF (publisher's version ) (Open Access

    Sprouting angiogenesis versus co-option in tumor angiogenesis.

    No full text
    Item does not contain fulltex

    Do amyloid beta-associated factors co-deposit with Abeta in mouse models for Alzheimer's disease?

    Get PDF
    Contains fulltext : 88845.pdf (publisher's version ) (Open Access)Senile plaques and cerebral amyloid angiopathy in Alzheimer's disease (AD) patients not only consist of the amyloid-beta protein (Abeta), but also contain many different Abeta-associated factors, such as heparan sulfate proteoglycans, apolipoproteins, and complement factors. These factors may all influence Abeta deposition, aggregation, and clearance and therefore seem important in the development of human Abeta deposits. To study AD pathology and test new therapeutic agents, many different mouse models have been created. By transgenic expression of the amyloid-beta protein precursor, frequently in combination with other transgenes, these animals develop Abeta deposits that morphologically resemble their human counterparts. Whether this resemblance also applies to the presence of Abeta-associated factors is largely unclear. In this review, the co-deposition of factors known to associate with human Abeta deposits is summarized for several different AD mouse models

    EMAP-II expression is associated with macrophage accumulation in primary uveal melanoma.

    Get PDF
    Contains fulltext : 144480.pdf (publisher's version ) (Open Access)PURPOSE: Primary uveal melanoma may contain arcs, loops, and networks of periodic acid-Schiff (PAS)-positive patterns, along which numerous macrophages are present. Their recruitment into tumor tissue is mediated by chemotactic cytokines, for which vascular endothelial growth factor (VEGF)-C and endothelial monocyte-activating polypeptide ((EMAP)-II are candidates. In this study, the extent of VEGF-C and EMAP-II immunoreaction was related to infiltration of macrophages. METHODS: Serial sections of 25 primary uveal melanoma lesions were analyzed by immunohistochemistry. RESULTS: The analysis showed no correlation of VEGF-C immunoreaction and localization of macrophages. However, accumulation of macrophages occurred at sites of EMAP-II expression, especially in areas containing nests of tumor cells, surrounded by arcs, loops, and network patterns. In tumors with a strong EMAP-II immunoreaction, the adhesion molecule intracellular adhesion molecule (ICAM)-1 was strongly expressed on endothelial cells. EMAP-II-positive endothelial cells did not express VEGF receptor-2. However, extensive release of von Willebrand factor was observed. Signs of apoptosis were found neither in tumor cells nor endothelial cells. CONCLUSIONS: In uveal melanoma, macrophages accumulate at sites of EMAP-II expression. Based on the results, it may be hypothesized that this process of chemotaxis is facilitated by EMAP-II-dependent expression of ICAM-1 on vascular endothelial cells and concomitantly leads to localized vascular damage, as indicated by release of von Willebrand factor

    The role of vascular permeability factor and basic fibroblast growth factor in tumor angiogenesis

    Get PDF
    Contains fulltext : 21347___.PDF (publisher's version ) (Open Access
    • 

    corecore