scholarly journals Comparative functional responses of native and high-impacting invasive fishes: impact predictions for native prey populations

2016 ◽  
Vol 26 (4) ◽  
pp. 533-540 ◽  
Author(s):  
Zhiqiang Guo ◽  
Danny Sheath ◽  
Fatima Amat Trigo ◽  
J. Robert Britton
Keyword(s):  
Functional Responses ◽  
Invasive Fishes ◽  
Impact Predictions ◽  
Prey Populations

scholarly journals The Combined Effects of Warming and Body Size on the Stability of Predator-Prey Interactions

2022 ◽  
Vol 9 ◽  
Author(s):  
Pavel Kratina ◽  
Benjamin Rosenbaum ◽  
Bruno Gallo ◽  
Elena L. Horas ◽  
Eoin J. O’Gorman
Keyword(s):  
Body Size ◽  
Trophic Interactions ◽  
Handling Time ◽  
Size Ratio ◽  
Interactive Effects ◽  
Functional Responses ◽  
Ample Evidence ◽  
Predator Prey ◽  
The Stability ◽  
Prey Populations

Environmental temperature and body size are two prominent drivers of predation. Despite the ample evidence of their independent effects, the combined impact of temperature and predator-prey body size ratio on the strength and stability of trophic interactions is not fully understood. We experimentally tested how water temperature alters the functional response and population stability of dragonfly nymphs (Cordulegaster boltonii) feeding on freshwater amphipods (Gammarus pulex) across a gradient of their body size ratios. Attack coefficients were highest for small predators feeding on small prey at low temperatures, but shifted toward the largest predators feeding on larger prey in warmer environments. Handling time appeared to decrease with increasing predator and prey body size in the cold environment, but increase at higher temperatures. These findings indicate interactive effects of temperature and body size on functional responses. There was also a negative effect of warming on the stability of predator and prey populations, but this was counteracted by a larger predator-prey body size ratio at higher temperatures. Here, a greater Hill exponent reduced feeding at low prey densities when predators were much larger than their prey, enhancing the persistence of both predator and prey populations in the warmer environment. These experimental findings provide new mechanistic insights into the destabilizing effect of warming on trophic interactions and the key role of predator-prey body size ratios in mitigating these effects.

Tyrosine kinase-dependent phosphatidylinositol turnover and functional responses in the FcεR1 signalling pathway

1991 ◽  
Vol 179 (1) ◽  
pp. 551-557 ◽  
Author(s):  
Grace G. Deanin ◽  
A.Marina Martinez ◽  
Janet R. Pfeiffer ◽  
Mary E. Gardner ◽  
Janet M. Oliver
Keyword(s):  
Tyrosine Kinase ◽  
Signalling Pathway ◽  
Functional Responses ◽  
Phosphatidylinositol Turnover

Expression of P2X7purinoceptors on human lymphocytes and monocytes: evidence for nonfunctional P2X7receptors

2000 ◽  
Vol 279 (4) ◽  
pp. C1189-C1197 ◽  
Author(s):  
B. J. Gu ◽  
W. Y. Zhang ◽  
L. J. Bendall ◽  
I. P. Chessell ◽  
G. N. Buell ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
Adhesion Molecule ◽  
Human Lymphocytes ◽  
Normal Subjects ◽  
Cell Types ◽  
Surface Expression ◽  
Lymphocytic Leukemia ◽  
Functional Responses ◽  
Intracellular Expression ◽  
Selective Channel

Lymphocytes from normal subjects and patients with B-chronic lymphocytic leukemia (B-CLL) show functional responses to extracellular ATP characteristic of the P2X7receptor (previously termed P2Z). These responses include opening of a cation-selective channel/pore that allows entry of the fluorescent dye ethidium and activation of a membrane metalloprotease that sheds the adhesion molecule L-selectin. The surface expression of P2X7receptors was measured in normal leucocytes, platelets, and B-CLL lymphocytes and correlated with their functional responses. Monocytes showed four- to fivefold greater expression of P2X7than B, T, and NK lymphocytes, whereas P2X7expression on neutrophils and platelets was weak. All cell types demonstrated abundant intracellular expression of this receptor. All 12 subjects with B-CLL expressed lymphocyte P2X7at about the same level as B lymphocytes from normal subjects. P2X7function, measured by ATP-induced uptake of ethidium, correlated closely with surface expression of this receptor in normal and B-CLL lymphocytes and monocytes ( n = 47, r = 0.70; P< 0.0001). However, in three patients the ATP-induced uptake of ethidium into the malignant B lymphocytes was low or absent. The lack of P2X7function in these B lymphocytes was confirmed by the failure of ATP to induce Ba2+uptake into their lymphocytes. This lack of function of the P2X7receptor resulted in a failure of ATP-induced shedding of L-selectin, an adhesion molecule that directs the recirculation of lymphocytes from blood into the lymph node.

Species identity matters: Functional responses to warming in congeneric turfs differ from those of a canopy algae but are species-specific

2021 ◽  
pp. 107396
Author(s):  
Isabella Provera ◽  
Cristina Piñeiro-Corbeira ◽  
Rodolfo Barreiro ◽  
Laura Díaz-Acosta ◽  
Pilar Díaz-Tapia
Keyword(s):  
Functional Responses ◽  
Species Identity ◽  
Species Specific ◽  
Canopy Algae

scholarly journals Functional response of Harmonia axyridis preying on Acyrthosiphon pisum nymphs: the effect of temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yasir Islam ◽  
Farhan Mahmood Shah ◽  
Xu Rubing ◽  
Muhammad Razaq ◽  
Miao Yabo ◽  
...  
Keyword(s):  
Functional Response ◽  
High Performance ◽  
Acyrthosiphon Pisum ◽  
Harmonia Axyridis ◽  
Effect Of Temperature ◽  
Functional Responses ◽  
Aphid Control ◽  
Host Aphid ◽  
Predator Foraging

AbstractIn the current study, we investigated the functional response of Harmonia axyridis adults and larvae foraging on Acyrthosiphon pisum nymphs at temperatures between 15 and 35 °C. Logistic regression and Roger’s random predator models were employed to determine the type and parameters of the functional response. Harmonia axyridis larvae and adults exhibited Type II functional responses to A. pisum, and warming increased both the predation activity and host aphid control mortality. Female and 4th instar H. axyridis consumed the most aphids. For fourth instar larvae and female H. axyridis adults, the successful attack rates were 0.23 ± 0.014 h−1 and 0.25 ± 0.015 h−1; the handling times were 0.13 ± 0.005 h and 0.16 ± 0.004 h; and the estimated maximum predation rates were 181.28 ± 14.54 and 153.85 ± 4.06, respectively. These findings accentuate the high performance of 4th instar and female H. axyridis and the role of temperature in their efficiency. Further, we discussed such temperature-driven shifts in predation and prey mortality concerning prey-predator foraging interactions towards biological control.

scholarly journals Biased ligands at opioid receptors: Current status and future directions

2021 ◽  
Vol 14 (677) ◽  
pp. eaav0320
Author(s):  
Tao Che ◽  
Hemlata Dwivedi-Agnihotri ◽  
Arun K. Shukla ◽  
Bryan L. Roth
Keyword(s):  
Opioid Receptors ◽  
Current Status ◽  
Functional Responses ◽  
Future Directions ◽  
Health Crisis ◽  
Biased Agonism ◽  
Opioid Ligands ◽  
Therapeutic Benefits ◽  
Ligand Discovery ◽  
Opioid Medications

The opioid crisis represents a major worldwide public health crisis that has accelerated the search for safer and more effective opioids. Over the past few years, the identification of biased opioid ligands capable of eliciting selective functional responses has provided an alternative avenue to develop novel therapeutics without the side effects of current opioid medications. However, whether biased agonism or other pharmacological properties, such as partial agonism (or low efficacy), account for the therapeutic benefits remains questionable. Here, we provide a summary of the current status of biased opioid ligands that target the μ- and κ-opioid receptors and highlight advances in preclinical and clinical trials of some of these ligands. We also discuss an example of structure-based biased ligand discovery at the μ-opioid receptor, an approach that could revolutionize drug discovery at opioid and other receptors. Last, we briefly discuss caveats and future directions for this important area of research.

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