217 research outputs found

    Acid-adaption by a medic microsymbiont: new insights from the genome of Sinorhizobium medicae WSM419

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    The poor availability of nitrogen is one of the principal factors limiting global biomass. Legumes are vital components of agricultural systems because of their ability to associate symbiotically with root nodule bacteria (RNB) and subsequently fix atmospheric nitrogen to a form that can be utilised by the plant partner. Furthermore, this symbiotic relationship provides available soil nitrogen for subsequent non-leguminous crops. This RNB-legume interaction is affected by a number of environmental factors. Progressive acidification of agricultural soils is one of the big challenges in agriculture as soil acidity negatively impacts legume productivity. One genus of RNB, Sinorhizobium, is particularly acid-sensitive causing a major reduction in Medicago productivity in acidic soils. Due to the importance of Medic pasture production, alternative strains have been captured, and are still being captured, from the genetic pool that display superior acid tolerance characteristics. This presentation will focus on the acid-tolerant species S. medicae (previously known as S. meliloti) and in particular on the previously used commercial inoculant WSM419

    I understand you feel that way, but I feel this way: The benefits of I-language and communicating perspective during conflict

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    Using hypothetical scenarios, we provided participants with potential opening statements to a conflict discussion that varied on I/you language and communicated perspective. Participants rated the likelihood that the recipient of the statement would react in a defensive manner. Using I-language and communicating perspective were both found to reduce perceptions of hostility. Statements that communicated both self- and other-perspective using I-language (e.g. ‘I understand why you might feel that way, but I feel this way, so I think the situation is unfair’) were rated as the best strategy to open a conflict discussion. Simple acts of initial language use can reduce the chances that conflict discussion will descend into a downward spiral of hostility

    Mining the sequence data of Rhizobium Leguminosarum BV Trifolii WSM1325 and WM2304

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    Most clover rhizobial inoculants form effective nitrogen-fixing symbioses with either annual or perennial species (and very few with both). This constraint provides a considerable barrier to agricultural productivity since background populations of R. trifolii may nodulate with an incompatible host but ineffectively fix nitrogen (Yates et al 2008)

    Improving Grassland Quality in Communal Arable Lands in the Eastern Cape Province, South Africa

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    Overgrazing and shifting cultivation practise have severely degraded communal lands in the Eastern Cape of South Africa. Methods need to be developed to improve forage quality of grazing land, especially previously cultivated lands. The aim of the study was to investigate legume species to rehabilitate arable lands abandoned from cropping, to enhance their forage quality, productivity and ecological integrity. The study was conducted in seven communities within the Eastern Cape Province. This study showed that within the communal lands studied extensive areas have been cultivated and the majority of this land is now poorly utilised. Natural grasslands ploughed for cropping did not recover its original composition and therefore lost its primary ecological condition. New improved legume cultivars can significantly enhance forage quality on cultivated lands but individual species may not have the resilience to survive nutrient poor lands and variable winter rainfall. This study shows that using a mixture of annual and perennial legume species with different life traits contributed to enhanced forage quality, especially during winter when the nutritional value of grasses was low. Because of management constraints, pasture legumes cannot be seen as stand-alone pastures, but provide a mechanism to extend the forage potential of communal grazing lands

    Semi-quantitative analysis of cannabinoids in hemp (Cannabis sativa L.) using gas chromatography coupled to mass spectrometry

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    Background Hemp (Cannabis sativa L.) is a producer of cannabinoids. These organic compounds are of increasing interest due to their potential applications in the medicinal field. Advances in analytical methods of identifying and quantifying these molecules are needed. Method This study describes a new method of cannabinoid separation from plant material using gas chromatography-mass spectrometry (GC-MS) as the analytical tool to detect low abundance cannabinoids that will likely have implications for future therapeutical treatments. A novel approach was adopted to separate trichomes from plant material to analyse cannabinoids of low abundance not observed in raw plant extract. Required plant sample used for analysis was greatly reduced compared to other methods. Derivatisation method was simplified and deconvolution software was utilised to recognise unknown cannabinoid compounds of low abundance. Results The method produces well-separated spectra and allows the detection of major and minor cannabinoids. Ten cannabinoids that had available standards could be identified and quantified and numerous unidentified cannabinoids or pathway intermediates based on GC-MS spectra similarities could be extracted and analysed simultaneously with this method. Conclusions This is a rapid novel extraction and analytical method from plant material that can identify major and minor cannabinoids using a simple technique. The method will be of use to future researchers seeking to study the multitude of cannabinoids whose values are currently not understood

    Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419

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    Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont

    Domestic ventilation rates, indoor humidity and dust mite allergens : are our homes causing the asthma pandemic?

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    This paper is concerned with historical changes in domestic ventilation rates, relative humidity and the associated risk of house dust mite colonization. A controlled trial evaluated allergen and water vapour control measures on the level of house dust mite (HDM) Der p1 allergen and indoor humidity, concurrently with changes in lung function in 54 subjects who completed the protocol. Mechanical heat recovery ventilation units significantly reduced moisture content in the active group, while HDM allergen reservoirs in carpets and beds were reduced by circa 96%. Self reported health status confirmed a significant clinical improvement in the active group. The study can form the basis for assessing minimum winter ventilation rates that can suppress RH below the critical ambient equilibrium humidity of 60% and thus inhibit dust mite colonization and activity in temperate and maritime in' uenced climatic regions

    Finding just the right recipe: nutrient requirements on Christmas Island

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    There is no history of large-scale agriculture on Christmas Island. As a result, there is a heavy reliance on imported produce
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