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81.
82.
Henly Samuel E.; Ostdiek Allison; Blackwell Erika; Knutie Sarah; Dunlap Aimee S.; Stephens David W. 《Behavioral ecology》2008,19(1):154-162
Experimental animals often prefer small but immediate rewardseven when larger-delayed rewards provide a higher rate of intake.This impulsivity has important implications for models of foragingand cooperation. Behavioral ecologists have hypothesized thatanimals discount delayed rewards because delay imposes a collectionrisk. According to this long-standing hypothesis, delay reducesvalue because an interruption that occurs while an animal iswaiting may prevent it from collecting the delayed reward. Althoughthere have been many experimental demonstrations of animal preferencesfor immediacy, none have included any interruptions. This paperdevelops a simple model of discounting by interruptions andthen tests this model experimentally. The model considers theeffects of interruption rate and duration on choice behavior.The experiment tests the effects of interruptions on the choicebehavior of captive blue jays (Cyanocitta cristata) using afactorial design that manipulates the rate and duration of interruptions.The results do not support the discounting-by-interruptionshypothesis. This represents one of several lines of evidencesuggesting that investigators should seek alternative explanationsof the animal impulsivity. 相似文献
83.
Diego A. Zárrate-Charry Aimee L. Massey José F. González-Maya Matthew G. Betts 《Biodiversity and Conservation》2018,27(13):3373-3392
Human–wildlife conflict, habitat loss, and prey hunting are the main threats to carnivore species worldwide. Forest conversion as consequence of deforestation and agricultural expansion increases the proximity between carnivores and humans, thereby escalating conflicts. Knowledge about carnivore species in data-poor countries, such as Colombia, is scarce which has the potential to result in poor landscape planning decisions. For many species, the only existing spatial information resides in expert-driven approaches which result in coarse-resolution ‘extent-of-occurrence’ maps. There is an increasing need for the development of methodologies to identify conservation and management areas at appropriate scales. Multi-criteria approaches will allow the inclusion of diverse species attributes enabling environmental institutions to address complex landscape decisions that result in conservation and management of carnivore habitat. We present a multi-criteria spatial identification tool for conservation and management areas, focused on Jaguars (Panthera onca) in the Sierra Nevada de Santa Marta, in northern Colombia. Our approach identifies areas based on the relationship between three spatial criteria: (1) suitable habitat patches, (2) habitat connectivity, and (3) zones of higher likelihood of human–jaguar conflict. We identified areas with the presence of at least one spatial criteria in 32% of the study area. Only 16.28% of these occur within protected areas (PAs) and the remaining fall on private lands (83.72%), either within (35.68%) or outside (48.04%) buffer zones of PAs. Our results highlight the need for multi-stakeholder collaborative approaches given that most proposed conservation areas fall on private rather than public lands. 相似文献
84.
Aimee K. Bence 《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):383-394
There is a clear need for agents with novel mechanisms of action to provide new therapeutic approaches for the treatment of pancreatic cancer. Owing to its structural similarity to l-arginine, l-canavanine, the δ-oxa-analog of l-arginine, is a substrate for arginyl tRNA synthetase and is incorporated into nascent proteins in place of l-arginine. Although l-arginine and l-canavanine are structurally similar, the oxyguanidino group of l-canavanine is significantly less basic than the guanidino group of l-arginine. Consequently, l-canavanyl proteins lack the capacity to form crucial ionic interactions, resulting in altered protein structure and function, which leads to cellular death. Since l-canavanine is selectively sequestered by the pancreas, it may be especially useful as an adjuvant therapy in the treatment of pancreatic cancer. This novel mechanism of cytotoxicity forms the basis for the anticancer activity of l-canavanine and thus, arginyl tRNA synthetase may represent a novel target for the development of such therapeutic agents. 相似文献
85.
Ludmila Matos Baltazar Aimee E. Krausz Ana Camila Oliveira Souza Brandon L. Adler Angelo Landriscina Tagai Musaev Joshua D. Nosanchuk Adam J. Friedman 《PloS one》2015,10(3)
Antimicrobial photodynamic inhibition (aPI) utilizes radical stress generated from the excitation of a photosensitizer (PS) with light to destroy pathogens. Its use against Trichophyton rubrum, a dermatophytic fungus with increasing incidence and resistance, has not been well characterized. Our aim was to evaluate the mechanism of action of aPI against T. rubrum using curcumin as the PS in both free and nanoparticle (curc-np) form. Nanocarriers stabilize curcumin and allow for enhanced solubility and PS delivery. Curcumin aPI, at optimal conditions of 10 μg/mL of PS with 10 J/cm2 of blue light (417 ± 5 nm), completely inhibited fungal growth (p<0.0001) via induction of reactive oxygen (ROS) and nitrogen species (RNS), which was associated with fungal death by apoptosis. Interestingly, only scavengers of RNS impeded aPI efficacy, suggesting that curcumin acts potently via a nitrosative pathway. The curc-np induced greater NO• expression and enhanced apoptosis of fungal cells, highlighting curc-np aPI as a potential treatment for T. rubrum skin infections. 相似文献
86.
Dimitris Petroutsos Aimee M. Terauchi Andreas Busch Ingrid Hirschmann Sabeeha S. Merchant Giovanni Finazzi Michael Hippler 《The Journal of biological chemistry》2009,284(47):32770-32781
PGRL1 RNA and protein levels are increased in iron-deficient Chlamydomonas reinhardtii cells. In an RNAi strain, which accumulates lower PGRL1 levels in both iron-replete and -starved conditions, the photosynthetic electron transfer rate is decreased, respiratory capacity in iron-sufficient conditions is increased, and the efficiency of cyclic electron transfer under iron-deprivation is diminished. Pgrl1-kd cells exhibit iron deficiency symptoms at higher iron concentrations than wild-type cells, although the cells are not more depleted in cellular iron relative to wild-type cells as measured by mass spectrometry. Thiol-trapping experiments indicate iron-dependent and redox-induced conformational changes in PGRL1 that may provide a link between iron metabolism and the partitioning of photosynthetic electron transfer between linear and cyclic flow. We propose, therefore, that PGRL1 in C. reinhardtii may possess a dual function in the chloroplast; that is, iron sensing and modulation of electron transfer. 相似文献
87.
Yongming Li Haijie Xiao Christelle de Renty Aimee Jaramillo-Lambert Zhiyong Han Melvin L. DePamphilis Kristy J. Brown Wenge Zhu 《The Journal of biological chemistry》2012,287(51):42469-42479
DNA replication in all eukaryotes starts with the process of loading the replicative helicase MCM2–7 onto chromatin during late mitosis of the cell cycle. MCM2–7 is a key component of the prereplicative complex (pre-RC), which is loaded onto chromatin by the concerted action of origin recognition complex, Cdc6, and Cdt1. Here, we demonstrate that And-1 is assembled onto chromatin in late mitosis and early G1 phase before the assembly of pre-RC in human cells. And-1 forms complexes with MCM2–7 to facilitate the assembly of MCM2–7 onto chromatin at replication origins in late mitosis and G1 phase. We also present data to show that depletion of And-1 significantly reduces the interaction between Cdt1 and MCM7 in G1 phase cells. Thus, human And-1 facilitates loading of the MCM2–7 helicase onto chromatin during the assembly of pre-RC. 相似文献
88.
Virginia M. Tanis Genesis M. Bacani Jonathan M. Blevitt Christa C. Chrovian Shelby Crawford Aimee De Leon Anne M. Fourie Laurent Gomez Cheryl A. Grice Krystal Herman Aaron M. Kearney Adrienne M. Landry-Bayle Alice Lee-Dutra Jay Nelson Jason P. Riley Alejandro Santillán John J.M. Wiener Xiaohua Xue Arlene L. Young 《Bioorganic & medicinal chemistry letters》2012,22(24):7504-7511
Previously, benzthiazole containing LTA4H inhibitors were discovered that were potent (1–3), but were associated with the potential for a hERG liability. Utilizing medicinal chemistry first principles (e.g., introducing rigidity, lowering c Log D) a new benzthiazole series was designed, congeners of 1–3, which led to compounds 7a, 7c, 12a–d which exhibited LTA4H IC50 = 3–6 nM and hERG Dofetilide Binding IC50 = 8.9–> >10 μM. 相似文献
89.
90.
BCAAs (branched-chain amino acids) are indispensable (essential) amino acids that are required for body protein synthesis. Indispensable amino acids cannot be synthesized by the body and must be acquired from the diet. The BCAA leucine provides hormone-like signals to tissues such as skeletal muscle, indicating overall nutrient sufficiency. BCAA metabolism provides an important transport system to move nitrogen throughout the body for the synthesis of dispensable (non-essential) amino acids, including the neurotransmitter glutamate in the central nervous system. BCAA metabolism is tightly regulated to maintain levels high enough to support these important functions, but at the same time excesses are prevented via stimulation of irreversible disposal pathways. It is well known from inborn errors of BCAA metabolism that dysregulation of the BCAA catabolic pathways that leads to excess BCAAs and their alpha-keto acid metabolites results in neural dysfunction. In this issue of Biochemical Journal, Joshi and colleagues have disrupted the murine BDK (branched-chain alpha-keto acid dehydrogenase kinase) gene. This enzyme serves as the brake on BCAA catabolism. The impaired growth and neurological abnormalities observed in this animal show conclusively the importance of tight regulation of indispensable amino acid metabolism. 相似文献