• 제목/요약/키워드: CSIRO

검색결과 154건 처리시간 0.022초

Application of Recent DNA/RNA-based Techniques in Rumen Ecology

  • McSweeney, C.S.;Denman, S.E.;Wright, A.-D.G.;Yu, Z.
    • Asian-Australasian Journal of Animal Sciences
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    • 제20권2호
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    • pp.283-294
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    • 2007
  • Conventional culture-based methods of enumerating rumen microorganisms (bacteria, archaea, protozoa, and fungi) are being rapidly replaced by nucleic acid-based techniques which can be used to characterise complex microbial communities without incubation. The foundation of these techniques is 16S/18S rDNA sequence analysis which has provided a phylogenetically based classification scheme for enumeration and identification of microbial community members. While these analyses are very informative for determining the composition of the microbial community and monitoring changes in population size, they can only infer function based on these observations. The next step in functional analysis of the ecosystem is to measure how specific and, or, predominant members of the ecosystem are operating and interacting with other groups. It is also apparent that techniques which optimise the analysis of complex microbial communities rather than the detection of single organisms will need to address the issues of high throughput analysis using many primers/probes in a single sample. Nearly all the molecular ecological techniques are dependant upon the efficient extraction of high quality DNA/RNA representing the diversity of ruminal microbial communities. Recent reviews and technical manuals written on the subject of molecular microbial ecology of animals provide a broad perspective of the variety of techniques available and their potential application in the field of animal science which is beyond the scope of this treatise. This paper will focus on nucleic acid based molecular methods which have recently been developed for studying major functional groups (cellulolytic bacteria, protozoa, fungi and methanogens) of microorganisms that are important in nutritional studies, as well as, novel methods for studying microbial diversity and function from a genomics perspective.

Metal effects in Mn-Na2WO4/SiO2 upon the conversion of methane to higher hydrocarbons

  • Tang, Liangguang;Choi, Jonghyun;Lee, Woo Jin;Patel, Jim;Chiang, Ken
    • Advances in Energy Research
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    • 제5권1호
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    • pp.13-29
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    • 2017
  • The roles of Na, Mn, W and silica, and the synergistic effects between each metal in the $MnNa_2WO_4/SiO_2$ catalyst have been investigated for oxidative coupling of methane (OCM). The crystallisation of amorphous silica during calcination at $900^{\circ}C$ was promoted primarily by Na, but Mn and W also facilitated this process. The interaction between Na and Mn tended to increase the extent of conversion of $Mn_3O_4$ to $Mn_2O_3$. The formation of $Na_2WO_4$ was dependent on the order in which Na and W were introduced to the catalyst. The impregnation of W before Na resulted in the formation of $Na_2WO_4$, but this did not occur when the impregnation order was reversed. $MnWO_4$ formed in all cases where Mn and W were introduced into the silica support, regardless of the impregnation order; however, the formation of $MnWO_4$ was inhibited in the presence of Na. Of the prepared samples in which a single metal oxide was introduced to silica, only $Mn/SiO_2$ showed OCM activity with significant oxygen conversion, thus demonstrating the important role that Mn plays in promoting oxygen transfer in the reaction. The impregnation order of W and Na is critical for catalyst performance. The active site, which involves a combination of Na-Si-W-O, can be formed in situ when distorted $WO_4^{2-}$ interacts with silica during the crystallisation process facilitated by Na. This can only occur if the impregnation of W occurs before Na addition, or if the two components are introduced simultaneously.

Characterising Forages for Ruminant Feeding

  • Dynes, R.A.;Henry, D.A.;Masters, D.G.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권1호
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    • pp.116-123
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    • 2003
  • Forages are the most important feed resource for ruminants worldwide, whether fed as pastures, forage crops or conserved hay, silage or haylage. There is large variability in the quality of forages so measurement and prediction of feeding value and nutritive value are essential for high levels of production. Within a commercial animal production system, methods of prediction must be inexpensive and rapid. At least 50% of the variation in feeding value of forages is due to variation in voluntary feed intake. Identification of the factors that constrain voluntary feed intake allows these differences to be managed and exploited in forage selection. Constraints to intake have been predicted using combinations of metabolic and physical factors within the animal while simple measurements such as the energy required to shear the plant material are related to constraints to intake with some plant material. Animals respond to both pre- and post-ingestive feedback signals from forages. Pre-ingestive signals may play a role in intake with signals including taste, odour and texture together with learned aversions to nutrients or toxins (post-ingestive feedback signals). The challenge to forage evaluation is identification of the factors which are most important contributors to these feedback signals. Empirical models incorporating chemical composition are also widely used. The models tend to be useful within the ranges of the datasets used in their development but none can claim to have universal application. Mechanistic models are becoming increasingly complex and sophisticated and incorporate both feed characteristics and use of biochemical pathways within the animal. Improvement in utilisation through the deliberate selection of pasture plants for high feeding value appears to have potential and has been poorly exploited. Use of Near Infrared Reflectance Spectroscopy is a simple method that offers significant potential for the preliminary screening of plants with genetic differences in feeding value. Near Infrared Reflectance Spectroscopy will only be as reliable as the calibration sets from which the equations are generated.

시추공간 전기비저항 토모그래피를 이용한 $CO_2$ 주입 모니터링 (Monitoring $CO_2$ injection with cross-hole electrical resistivity tomography)

  • Christensen, N.B.;Sherlock, D.;Dodds, K.
    • 지구물리와물리탐사
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    • 제9권1호
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    • pp.44-49
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    • 2006
  • 이 연구에서는 $CO_2$ 주입 모니터링에서의 전기비저항 토모그래피(ERT)의 분해능에 대해 조사한다. $CO_2$ 주입체 양쪽의 케이싱 없는 시추공에서 단극자 및 양극자 전극 배열이 사용된다. 주입 전 및 주입에 따른 3단계 모델에 대한 반응이 계산되고, 잡음이 더해진 후의 이론 값들이 L1 과 L2 norm을 사용해 역산된다. 역산결과는 어느 정도 수준이상의 $CO_2$ 부피가 확실히 감지됨을 보여준다. 대부분의 경우에 L1 norm의 경우가 L2에 비해 우월함이 판명되었다. 역산 결과를 주입 전 모델의 역산결과로 정규화하면 전기비저항이 변화하는 부분의 훌륭한 영상을 보여주며, 비저항의 전체적인 변화를 통합해서 판단하면 전체 주입된 부피에 대한 타당한 측정이 이루어짐이 입증된다.

Changing Wheat Quality with the Modification of Storage Protein Structure

  • Tamas, Laszlo;Bekes, Ferenc;Morrell, Matthew K.;Appels, Rudi
    • Journal of Plant Biotechnology
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    • 제1권1호
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    • pp.13-19
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    • 1999
  • The visco-elastic properties of gluten are major determinants of the processing properties of doughs. These visco-elastic properties are strongly influenced by the ratio of monomeric and polymeric proteins and the size distribution of the polymeric proteins, which make up the gluten fraction of the dough. Recent studies have revealed that other features, such as the number of the cysteine residues of the HMW-GS, also play an important role in determining the functional characteristics. To modify the processing properties at molecular level, the relationship between the structure of molecules and dough properties has to be understood. In order to explore the relationships between individual proteins and dough properties, we have developed procedures for incorporating bacterially expressed proteins into doughs, and measuring their functional properties in small-scale equipment. A major problem in investigating the structure/function relationships of individual seed storage proteins is to obtain sufficient amounts of pure polypeptides from the complex families of proteins expressed in the endosperm. Therefore, we have established a simplified model system in which we produce specific protein genes through bacterial expression and test their functional properties in smallscale apparatus after incorporation into base flour. An S poor protein gene has been chosen as a template gene. This template gene has been modified using standard recombinant DNA techniques in order to test the effects of varying the number and position of cysteine residues, and the size of the protein. Doughs have been mixed in small scale apparatus and characterized with respect to their polymeric composition and their functional properties, including dough mixing, extensibility and small scale bating. We conclude that dough characteristics can be manipulated in a predictable manner by altering the cysteine residues and the size of high molecular weight glutenins.

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The Great Western Woodlands TERN SuperSite: ecosystem monitoring infrastructure and key science learnings

  • Suzanne M Prober;Georg Wiehl;Carl R Gosper;Leslie Schultz;Helen Langley;Craig Macfarlane
    • Journal of Ecology and Environment
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    • 제47권4호
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    • pp.272-281
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    • 2023
  • Ecosystem observatories are burgeoning globally in an endeavour to detect national and global scale trends in the state of biodiversity and ecosystems in an era of rapid environmental change. In this paper we highlight the additional importance of regional scale outcomes of such infrastructure, through an introduction to the Great Western Woodlands TERN (Terrestrial Ecosystem Research Network) SuperSite, and key findings from three gradient plot networks that are part of this infrastructure. The SuperSite was established in 2012 in the 160,000 km2 Great Western Woodlands region, in a collaboration involving 12 organisations. This region is globally significant for its largely intact, diverse landscapes, including the world's largest Mediterranean-climate woodlands and highly diverse sandplain shrublands. The dominant woodland eucalypts are fire-sensitive, requiring hundreds of years to regrow after fire. Old-growth woodlands are highly valued by Indigenous and non-Indigenous communities, and managing impacts of climate change and the increasing extent of intense fires are key regional management challenges. Like other TERN SuperSites, the Great Western Woodlands TERN SuperSite includes a core eddy-covariance flux tower measuring exchanges of carbon, water and energy between the vegetation and atmosphere, along with additional environmental and biodiversity monitoring around the tower. The broader SuperSite incorporates three gradient plot networks. Two of these represent aridity gradients, in sandplains and woodlands, informing regional climate adaptation and biodiversity management by characterising biodiversity turnover along spatial climate gradients and acting as sentinels for ecosystem change over time. For example, the sandplains transect has demonstrated extremely high spatial turnover rates in plant species, that challenge traditional approaches to biodiversity conservation. The third gradient plot network represents a 400-year fire-age gradient in Eucalyptus salubris woodlands. It has enabled characterisation of post-fire recovery of vegetation, birds and invertebrates over multi-century timeframes, and provided tools that are directly informing management to reduce stand-replacing fires in eucalypt woodlands. By building regional partnerships and applying globally or nationally consistent methodologies to regional scale questions, ecological observatories have the power not only to detect national and global scale trends in biodiversity and ecosystems, but to directly inform environmental decisions that are critical at regional scales.