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991.
992.
A key step in the evolution of multicellular organisms is the formation of cooperative multicellular groups. It has been suggested that predation pressure may promote multicellular group formation in some algae and bacteria, with cells forming groups to lower their chance of being eaten. We use the green alga Chlorella vulgaris and the protist Tetrahymena thermophila to test whether predation pressure can initiate the formation of colonies. We found that: (1) either predators or just predator exoproducts promote colony formation; (2) higher predator densities cause more colonies to form; and (3) colony formation in this system is facultative, with populations returning to being unicellular when the predation pressure is removed. These results provide empirical support for the hypothesis that predation pressure promotes multicellular group formation. The speed of the reversion of populations to unicellularity suggests that this response is due to phenotypic plasticity and not evolutionary change. 相似文献
993.
Lake Condah (Tae Rak) in south-western Victoria, Australia, is one of the world’s most ancient examples of traditional aquaculture, consisting of complex systems of traps and ponds used by Gunditjmara (Indigenous people) over millennia to collect short-finned eel (Anguilla australis) for consumption and trade. Artificial draining of the lake during the nineteenth century reduced surface water retention in the landscape and rendered most of the eel traps inoperable. In this paper, we describe the traditional eel fishery at Lake Condah and its historical and cultural significance to the Gunditjmara people. We document the impacts of European settlement on the traditional eel fishery, and describe the processes and events leading to eventual restoration of the lake and subsequent reactivation of major parts of the traditional aquaculture system. In addition to restoring an important ecological asset to the region, the restoration project provided significant benefits to the Gunditjmara people, including enhanced connection to country and culture, opportunities for economic development and employment, and increased capacity for traditional owners to progress and negotiate outcomes within regulatory and administrative frameworks. Aspects identified as critical to the ultimate success of the Lake Condah restoration project include: open and transparent lines of communication with stakeholders; building of trust and confidence with key individuals over sustained periods; use of strategic and business planning documents to guide activities; commissioning of high quality technical information to support and justify activities; representative leadership structures, and effective use of ‘two-way learning’ across western scientific and indigenous knowledge systems. 相似文献
994.
Avril Bell 《Ethnic and racial studies》2016,39(7):1170-1186
This paper explores convivial culture in a settler society. The paper draws on interview data from ethnographic research exploring how Māori and Pākehā worked together on a building project in a rural community. Both Māori and Pākehā participants reported their pleasure in engagements with each other that centred on Māori tikanga (protocols). In these encounters, Māori ‘difference’ was the catalyst for the development of new, convivial relationships. The paper argues that such everyday conviviality contributes to the process of decolonizing Māori–Pākehā relations at the level of everyday life. Through decolonizing conviviality Pakehā ‘become ordinary’ in Māori cultural contexts, and are offered the opportunity to come to understand themselves as embedded in colonial relationalities. Crucial to the development of such conviviality is the opportunity for face-to-face, embodied encounters with Māori in contexts where Māori cultural difference matters. 相似文献
995.
Lamia Sakouhi Sondès Rahoui Marouane Ben Massoud Shintaro Munemasa Ezzeddine EL Ferjani Yoshiyuki Murata Abdelilah Chaoui 《Journal of Plant Growth Regulation》2016,35(4):1064-1073
Impact of exogenous calcium and ethylene glycol tetraacetic acid (EGTA) supplement on chickpea (Cicer arietinum L.) germinating seeds exposed to cadmium stress for 6 days was studied. Ca and EGTA late treatment (3 days) alleviated growth inhibition and decreased Cd accumulation as well as lipid peroxidation and protein carbonylation in both root and shoot cells. Exogenous effector application relieved Cd-induced cell death which was associated with a constant level of ATP, which was considered as an apoptotic-like process. Redox balance was examined through the study of the redox state of pyridine nucleotide couples NAD+/NADH and NADP+/NADPH as well as their related oxidative [NAD(P)H-oxidase] and dehydrogenase (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and malate dehydrogenase) enzyme activities. The present research illustrated an ameliorative effect of Ca and EGTA on growth of Cd-exposed chickpea seedlings that occurs through the protection of sensitive cell sites from Cd-induced oxidation, namely membrane lipids and proteins, rather than the improvement of recycling capabilities of the cellular reducing power. 相似文献
996.
997.
We present models of semantic transparency in which the perceived transparency of English noun–noun compounds, and of their constituent words, is predicted on the basis of the expectedness of their semantic structure. We show that such compounds are perceived as more transparent when the first noun is more frequent, hence more expected, in the language generally; when the compound semantic relation is more frequent, hence more expected, in association with the first noun; and when the second noun is more productive, hence more expected, as the second element of a noun–noun compound. Taken together, our models of compound and constituent transparency lead us to two conclusions. Firstly, although compound transparency is a function of the transparencies of the constituents, the two constituents differ in the nature of their contribution. Secondly, since all the significant predictors in our models of compound transparency are also known predictors of processing speed, perceived transparency may itself be a reflex of ease of processing. 相似文献
998.
Carola Marzi Lesca M Holdt Giovanni Fiorito Pei-Chien Tsai Anja Kretschmer Simone Wahl Simonetta Guarrera Daniel Teupser Tim D. Spector Licia Iacoviello Carlotta Sacerdote Konstantin Strauch Serene Lee Wolfgang E. Thasler Annette Peters Barbara Thorand Petra Wolf Holger Prokisch Rosario Tumino Christian Gieger Vittorio Krogh Salvatore Panico Jordana T. Bell Giuseppe Matullo Melanie Waldenberger Harald Grallert Wolfgang Koenig 《PloS one》2016,11(11)
BackgroundElevated levels of C-reactive protein (CRP, determined by a high-sensitivity assay) indicate low-grade inflammation which is implicated in many age-related disorders. Epigenetic studies on CRP might discover molecular mechanisms underlying CRP regulation. We aimed to identify DNA methylation sites related to CRP concentrations in cells and tissues regulating low-grade inflammation.ResultsGenome-wide DNA methylation was measured in peripheral blood in 1,741 participants of the KORA F4 study using Illumina HumanMethylation450 BeadChip arrays. Four CpG sites (located at BCL3, AQP3, SOCS3, and cg19821297 intergenic at chromosome 19p13.2, P ≤ 1.01E-07) were significantly hypomethylated at high CRP concentrations independent of various confounders including age, sex, BMI, smoking, and white blood cell composition. Findings were not sex-specific. CRP-related top genes were enriched in JAK/STAT pathways (Benjamini-Hochberg corrected P < 0.05). Results were followed-up in three studies using DNA from peripheral blood (EPICOR, n = 503) and adipose tissue (TwinsUK, n = 368) measured as described above and from liver tissue (LMU liver cohort, n = 286) measured by MALDI-TOF mass spectrometry using EpiTYPER. CpG sites at the AQP3 locus (significant p-values in peripheral blood = 1.72E-03 and liver tissue = 1.51E-03) and the SOCS3 locus (p-values in liver < 2.82E-05) were associated with CRP in the validation panels.ConclusionsEpigenetic modifications seem to engage in low-grade inflammation, possibly via JAK/STAT mediated pathways. Results suggest a shared relevance across different tissues at the AQP3 locus and highlight a role of DNA methylation for CRP regulation at the SOCS3 locus. 相似文献
999.
Recent and emerging innovations in Salmonella detection: a food and environmental perspective
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Rebecca L. Bell Karen G. Jarvis Andrea R. Ottesen Melinda A. McFarland Eric W. Brown 《Microbial biotechnology》2016,9(3):279-292
Salmonella is a diverse genus of Gram‐negative bacilli and a major foodborne pathogen responsible for more than a million illnesses annually in the United States alone. Rapid, reliable detection and identification of this pathogen in food and environmental sources is key to safeguarding the food supply. Traditional microbiological culture techniques have been the ‘gold standard’ for State and Federal regulators. Unfortunately, the time to result is too long to effectively monitor foodstuffs, especially those with very short shelf lives. Advances in traditional microbiology and molecular biology over the past 25 years have greatly improved the speed at which this pathogen is detected. Nonetheless, food and environmental samples possess a distinctive set of challenges for these newer, more rapid methodologies. Furthermore, more detailed identification and subtyping strategies still rely heavily on the availability of a pure isolate. However, major shifts in DNA sequencing technologies are meeting this challenge by advancing the detection, identification and subtyping of Salmonella towards a culture‐independent diagnostic framework. This review will focus on current approaches and state‐of‐the‐art next‐generation advances in the detection, identification and subtyping of Salmonella from food and environmental sources. 相似文献
1000.
Pig carcasses, as human proxies, were placed on the seabed at a depth of 300 m, in the Strait of Georgia and observed continuously by a remotely operated camera and instruments. Two carcasses were deployed in spring and two in fall utilizing Ocean Network Canada’s Victoria Experimental Network under the Sea (formerly VENUS) observatory. A trial experiment showed that bluntnose sixgill sharks could rapidly devour a carcass so a platform was designed which held two matched carcasses, one fully exposed, the other covered in a barred cage to protect it from sharks, while still allowing invertebrates and smaller vertebrates access. The carcasses were deployed under a frame which supported a video camera, and instruments which recorded oxygen, temperature, salinity, density, pressure, conductivity, sound speed and turbidity at per minute intervals. The spring exposed carcass was briefly fed upon by sharks, but they were inefficient feeders and lost interest after a few bites. Immediately after deployment, all carcasses, in both spring and fall, were very rapidly covered in vast numbers of lyssianassid amphipods. These skeletonized the carcasses by Day 3 in fall and Day 4 in spring. A dramatic, very localized drop in dissolved oxygen levels occurred in fall, exactly coinciding with the presence of the amphipods. Oxygen levels returned to normal once the amphipods dispersed. Either the physical presence of the amphipods or the sudden draw down of oxygen during their tenure, excluded other fauna. The amphipods fed from the inside out, removing the skin last. After the amphipods had receded, other fauna colonized such as spot shrimp and a few Dungeness crabs but by this time, all soft tissue had been removed. The amphipod activity caused major bioturbation in the local area and possible oxygen depletion. The spring deployment carcasses became covered in silt and a black film formed on them and on the silt above them whereas the fall bones remained uncovered and hence continued to be attractive to large numbers of spot shrimp. The carcass remains were recovered after 166 and 134 days respectively for further study. 相似文献