A note on E. B. Titchener and G. M. Whipple

Freeman, Frank S.

doi:10.1002/1520-6696(198404)20:2<177::aid-jhbs2300200206>3.0.co;2-8

Cited by 4 publications

(3 citation statements)

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“…In mountain systems, upper elevational range edges generally shift upward with warmer conditions (Freeman, Lee-Yaw, Sunday, & Hargreaves, 2018), whereas lower elevational range edges will likely contract with encroachment of more competitive species from lower elevations (Alexander et al, 2015). Our results suggest that disturbance might preserve populations near the trailing edge by reducing the effects of competitors.…”

Section: Discussionmentioning

confidence: 75%

Human trampling disturbance exerts different ecological effects at contrasting elevational range limits

Chardon

Rixen²,

Wipf³

et al. 2019

Journal of Applied Ecology

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1. Shifts in species geographic distributions in response to climate change have spurred numerous studies to determine which abiotic (e.g. climatic) and, less commonly, biotic (e.g. competitive) processes determine range limits. However, the impact of disturbances on range limits and their interactions with climatic and biotic effects is not well understood, despite their potential to alter competitive relationships between species or override climatic effects. Disturbance might have | 1391Journal of Applied Ecology CHARDON et Al.

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Section: Discussionmentioning

confidence: 75%

Human trampling disturbance exerts different ecological effects at contrasting elevational range limits

Chardon

Rixen²,

Wipf³

et al. 2019

Journal of Applied Ecology

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“…It is a complex of an apoprotein joined with oxygen and a light-emitting luciferin called coelenterazine. Because they are triggered by Ca 2ϩ ions to produce light, photoproteins have been widely used as calcium reporters (3)(4)(5). The high level of interest in these molecules has led to detailed studies of their chemistry and molecular biology: photoprotein genes have been cloned from several species of hydromedusae (6)(7)(8)(9)(10), and recently the tertiary structures of two photoproteins have been resolved (11,12).…”

mentioning

confidence: 99%

Can coelenterates make coelenterazine? Dietary requirement for luciferin in cnidarian bioluminescence

Haddock

Rivers²,

Robison³

2001

Proc. Natl. Acad. Sci. U.S.A.

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In the calcium-activated photoprotein aequorin, light is produced by the oxidation of coelenterazine, the luciferin used by at least seven marine phyla. However, despite extensive research on photoproteins, there has been no evidence to indicate the origin of coelenterazine within the phylum Cnidaria. Here we report that the hydromedusa Aequorea victoria is unable to produce its own coelenterazine and is dependent on a dietary supply of this luciferin for bioluminescence. Although they contain functional apophotoproteins, medusae reared on a luciferin-free diet are unable to produce light unless provided with coelenterazine from an external source. This evidence regarding the origins of luciferin in Cnidaria has implications for the evolution of bioluminescence and for the extensive use of coelenterazine among marine organisms.

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“…tions where platelets are involved. These include endothelial damage [14], reperfusion injury of ischemic myocardium [15] and severe vasoconstriction [S, 91. Reactive oxygen species derived from platelets might affect cells with which they come into intimate contact, such as endothelium, and this could result in amplification of platelet reactivity during thrombus formation.…”

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confidence: 99%

Role of hydroxyl radicals in the activation of human platelets

Iuliano

Pedersen

Praticò

et al. 1994

European Journal of Biochemistry

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Platelets primed by exposure to subthreshold concentrations of arachidonic acid or collagen are known to be activated by nanomolar levels of hydrogen peroxide. We here demonstrate that this effect is mediated by hydroxyl radicals (OH") formed in an extracellular Fenton-like reaction. H,O,-induced platelet aggregation, serotonin release and thromboxane A, productions were inhibited by OH" scavengers and by the iron chelator desferrioxamine ; hydroxyl radicals were detected directly by ESR measurements of the spin-trapped OH" adduct. The role of OH" was confirmed in experiments with exogenously added iron; free or EDTA-bound ferrous iron activated platelets in a process blocked by deoxyribose, mannitol or catalase, whereas ferric iron was without effect unless reductants were included. The activation by OH" depended on concomitant release of arachidonic acid and was blocked by the phospholipase A, inhibitors mepacrine and aristolochic acid, and by the Na+/K+ antiporter inhibitor ethylisopropylamiloride. In contrast, neomycin and staurosporin were without effects, indicating that phospholipase C and protein kinase C were not involved in the initial phase of activation. Neither radical formation nor arachidonic acid release was blocked by aspirin. In whole blood aggregation of platelets could be induced by H,O, generated upon specific stimulation of neutrophils by N-formyl-methionyl-leucyl-phenylalanine ; platelet activation and radical formation were blocked by the NADPH oxidase inhibitor diphenyliodonium as well as by catalase and mannitol. These results suggest that reactive oxygen species act as 'second messengers' during the initial phase of the platelet activation process.

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A note on E. B. Titchener and G. M. Whipple

Cited by 4 publications

References 0 publications

Human trampling disturbance exerts different ecological effects at contrasting elevational range limits

Human trampling disturbance exerts different ecological effects at contrasting elevational range limits

Can coelenterates make coelenterazine? Dietary requirement for luciferin in cnidarian bioluminescence

Role of hydroxyl radicals in the activation of human platelets

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