95 research outputs found
Symbiosis Specificity of the Preceding Host Plant Can Dominate but Not Obliterate the Association Between Wheat and Its Arbuscular Mycorrhizal Fungal Partners
The symbiosis established between arbuscular mycorrhizal fungi (AMF) and roots
of most land plants plays a key role in plant nutrient acquisition and alleviation of
environmental stresses. Despite the ubiquity of the symbiosis, AMF and host species
display significant specificity in their interactions. To clarify preferential associations
between wheat (Triticum aestivum) and AMF, we characterized root AMF communities in
the transition from two first host species, ryegrass (Lolium rigidum) and yellow-serradella
(Ornithopus compressus), grown separately or together, to a second host (wheat), by
sequencing the large subunit ribosomal DNA (LSU rDNA) gene. The response of AMF
communities in wheat to prior soil disturbance â and consequently of the mycelial
network [intact extraradical mycelium (ERM) vs. disrupted mycelium] established with
either of the first hosts â was also investigated. Since the outcome of a specific hostâ
symbiont interaction depends on the molecular responses of the host plant upon
microbial colonization, we studied the expression of six key symbiosis-related genes
in wheat roots. AMF communities on L. rigidum and O. compressus roots were clearly
distinct. Within an undisturbed ERM, wheat AMF communities were similar to that of
previous host, and O. compressus-wheat-AMF interactions supported a greater growth
of wheat than L. rigidum-wheat-AMF interactions. This effect declined when ERM was
disrupted, but generated a greater activation of symbiotic genes in wheat, indicating
that plant symbiotic program depends on some extent on the colonizing symbiont
propagule type. When a mixture of L. rigidum and O. compressus was planted, the
wheat colonization pattern resembled that of O. compressus, although this was not
reflected in a greater growth. These results show a lasting effect of previous hosts
in shaping wheat AMF communities through an efficient use of the established ERM,
although not completely obliterating hostâsymbiont specificity
Machine-assisted Cyber Threat Analysis using Conceptual Knowledge Discovery
Over the last years, computer networks have evolved into highly dynamic and interconnected environments, involving multiple heterogeneous devices and providing a myriad of services on top of them. This complex landscape has made it extremely difficult for security administrators to keep accurate and be effective in protecting their systems against cyber threats. In this paper, we describe our vision and scientific posture on how artificial intelligence techniques and a smart use of security knowledge may assist system administrators in better defending their networks. To that end, we put forward a research roadmap involving three complimentary axes, namely, (I) the use of FCA-based mechanisms for managing configuration vulnerabilities, (II) the exploitation of knowledge representation techniques for automated security reasoning, and (III) the design of a cyber threat intelligence mechanism as a CKDD process. Then, we describe a machine-assisted process for cyber threat analysis which provides a holistic perspective of how these three research axes are integrated together
Transcriptome Analysis of Wheat Roots Reveals a Di erential Regulation of Stress Responses Related to Arbuscular Mycorrhizal Fungi and Soil Disturbance
Abstract: Symbioses with soil microorganisms are central in shaping the diversity and productivity of
land plants and provide protection against a diversity of stresses, including metal toxicity. Arbuscular
mycorrhizal fungi (AMF) can form extensive extraradical mycelial networks (ERM), which are very
e cient in colonizing a new host. We quantified the responses of transcriptomes of wheat and one
AMF partner, Rhizoglomus irregulare, to soil disturbance (Undisturbed vs. Disturbed) and to two
di erent preceding mycotrophic species (Ornithopus compressus and Lolium rigidum). Soil disturbance
and preceding plant species engender di erent AMF communities in wheat roots, resulting in a
di erential tolerance to soil manganese (Mn) toxicity. Soil disturbance negatively impacted wheat
growth under manganese toxicity, probably due to the disruption of the ERM, and activated a large
number of stress and starvation-related genes. The O. compressus treatment, which induces a greater
Mn protection in wheat than L. rigidum, activated processes related to cellular division and growth,
and very few related to stress. The L. rigidum treatment mostly induced genes that were related to
oxidative stress, disease protection, and metal ion binding. R. irregulare cell division and molecular
exchange between nucleus and cytoplasm were increased by O. compressus. These findings are highly
relevant for sustainable agricultural systems, when considering a fit-for-purpose symbiosis
The Pirata Program : history, accomplishments, and future directions
Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 89 (2008): 1111â1125, doi:10.1175/2008BAMS2462.1.The Pilot Research Moored Array in the tropical Atlantic (PIRATA) was developed as a multinational observation network to improve our knowledge and understanding of oceanâatmosphere variability in the tropical Atlantic. PIRATA was motivated by fundamental scientific issues and by societal needs for improved prediction of climate variability and its impact on the economies of West Africa, northeastern Brazil, the West Indies, and the United States. In this paper the implementation of this network is described, noteworthy accomplishments are highlighted, and the future of PIRATA in the framework of a sustainable tropical Atlantic observing system is discussed. We demonstrate that PIRATA has advanced beyond a âPilotâ program and, as such, we have redefined the PIRATA acronym to be âPrediction and Research Moored Array in the Tropical Atlantic.
Nos caminhos da Luz, antigos palacetes da elite paulistana
The present article is dedicated to recover the memory of the old mansions built in\ud
the region of Luz Railway Station, from the beginning of the second half of the 19th Century\ud
onwards. It was around that time that the region became SĂŁo Paulo elites first residential\ud
neighbourhood, concentrating mansions that expressed the local elaborations of architectural\ud
Neo-classicism and Eclecticism. One intends to approach the interpretation processes that\ud
characterised such architectural production
PIRATA: A Sustained Observing System for Tropical Atlantic Climate Research and Forecasting
Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) is a multinational program initiated in 1997 in the tropical Atlantic to improve our understanding and ability to predict ocean-atmosphere variability. PIRATA consists of a network of moored buoys providing meteorological and oceanographic data transmitted in real time to address fundamental scientific questions as well as societal needs. The network is maintained through dedicated yearly cruises, which allow for extensive complementary shipboard measurements and provide platforms for deployment of other components of the Tropical Atlantic Observing System. This paper describes network enhancements, scientific accomplishments and successes obtained from the last 10 years of observations, and additional results enabled by cooperation with other national and international programs. Capacity building activities and the role of PIRATA in a future Tropical Atlantic Observing System that is presently being optimized are also described
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