Biol Rev Camb Philos Soc
December 2024
Climate change is one of the main challenges that human societies are currently facing. Given that forests represent major natural carbon sinks in terrestrial ecosystems, administrations worldwide are launching broad-scale programs to promote forests, including stands of non-native trees. Yet, non-native trees may have profound impacts on the functions and services of forest ecosystems, including the carbon cycle, as they may differ widely from native trees in structural and functional characteristics.
View Article and Find Full Text PDFThe spatial expansions of invasive organisms in the novel range are generally expected to follow an isolation-by-distance relationship (IBD) if the invasion is biologically driven; however, many invasions are facilitated anthropogenically. This research focused on the extant expansion patterns of cogongrass (). Cogongrass is a widespread invasive species throughout the southern United States (US).
View Article and Find Full Text PDFPredictive models are central to many scientific disciplines and vital for informing management in a rapidly changing world. However, limited understanding of the accuracy and precision of models transferred to novel conditions (their 'transferability') undermines confidence in their predictions. Here, 50 experts identified priority knowledge gaps which, if filled, will most improve model transfers.
View Article and Find Full Text PDFDefense-free space resulting from coevolutionarily naïve host plants recently has been implicated as a factor facilitating invasion success of some insect species. Host plants, however, may not be entirely defenseless against novel herbivore threats. Volatile chemical-mediated defense signaling, which allows plants to mount specific, rapid, and intense responses, may play a role in systems experiencing novel threats.
View Article and Find Full Text PDFEnvironmental niche models (ENMs) have gained enormous popularity as tools to investigate potential changes in species distributions resulting from climate change and species introductions. Despite recognition that species interactions can influence the dynamics of invasion spread, most implementations of ENMs focus on abiotic factors as the sole predictors of potential range limits. Implicit in this approach is the assumption that biotic interactions are relatively unimportant, either because of scaling issues, or because fundamental and realized niches are equivalent in a species' native range.
View Article and Find Full Text PDFA retrospective, matched case-control study was conducted in Jamaica's Western Regional Health Authority (WRHA). Forty-three individuals developing clinical leptospirosis between January 2005 and December 2007 (i.e.
View Article and Find Full Text PDFBlood-feeding arthropods secrete special salivary proteins that suppress the defensive reaction they induce in their hosts. This is in contrast to herbivores, which are thought to be helpless victims of plant defences elicited by their oral secretions. On the basis of the finding that caterpillar regurgitant can reduce the amount of toxic nicotine released by the tobacco plant Nicotiana tabacum, we investigate here whether specific salivary components from the caterpillar Helicoverpa zea might be responsible for this suppression.
View Article and Find Full Text PDFFew studies have experimentally investigated the influence of competition for light on structure and composition of wetland vascular plant communities, despite the well-documented high productivity in such systems. Influences of the dominant emergent wetland plant Juncus effusus on the surrounding macrophyte community were evaluated in a shallow freshwater wetland through two consecutive growing seasons. Permanent transects were constructed along diagonals of randomly oriented 1 m plots centered around isolated, colonizing J.
View Article and Find Full Text PDFBioorg Med Chem Lett
May 2001
A series of 1,4-benzodiazepines, N-1-substituted with an N-isopropyl-N-phenylacetamide moiety, was synthesized and screened for CCK-A agonist activity. In vitro agonist activity on isolated guinea pig gallbladder along with in vivo induction of satiety following intraperitoneal administration in a rat feeding assay was demonstrated.
View Article and Find Full Text PDFBioassays for allelochemical toxicity of aboveground Juncus effusus tissues were conducted with seeds and seedlings of Eleocharis obtusa and Scirpus cyperinus, two emergent sedge species (Cyperaceae) found sympatric with J. effusus, and with seeds and seedlings of J. effusus itself to evaluate potential autotoxicity.
View Article and Find Full Text PDFWe investigated the ability of sulfated cholecystokinin (26-33) (CCK-8) and cholecystokinin (30-33) (CCK-4) to induce taste aversion or avoidance conditioning (TAC) in a one-bottle testing paradigm after either intravenous (i.v.), intracerebroventricular (i.
View Article and Find Full Text PDFWe previously described a series of 3-(1H-indazol-3-ylmethyl)-1,5-benzodiazepine CCK-A agonists exemplified by compound 1 (GW 5823), which is the first reported binding selective CCK-A full agonist demonstrating oral efficacy in a rat feeding model. In this report we describe analogs of compound 1 designed to explore changes to the C3 and N1 pharmacophores and their effect on agonist activity and receptor selectivity. Agonist efficacy in this series was affected by stereoelectronic factors within the C3 moiety.
View Article and Find Full Text PDFAnalogs of the previously reported 1,5-benzodiazepine peripheral cholecystokinin (CCK-A) receptor agonist 1 were prepared which explore substitution and/or replacement of the C-3 phenyl urea moiety. Agonist efficacy on the isolated guinea pig gallbladder (GPGB) was retained with a variety of substituted ureas and amide analogs. Three compounds were identified which were orally active in the mouse gallbladder emptying assay (MGBE).
View Article and Find Full Text PDFDirected screening of compounds selected from the Glaxo registry file for contractile activity on the isolated guinea pig gallbladder (GPGB) identified a series of 1,5-benzodiazepines with peripheral cholecystokinin (CCK) receptor agonist activity. Agonist efficacy within this series was modulated by variation of substituents on the N1-anilinoacetamide moiety. Remarkably, a single methyl group confers agonist activity, with an N-isopropyl substituent providing optimal efficacy.
View Article and Find Full Text PDFAdministration of a relatively large IP dose of sulfated cholecystokinin (26-33) (CCK-8; 1.0 mumol/kg) consistently induced moderate taste aversion conditioning (TAC) using a 20-min, one-bottle test in Long-Evans rats. Because CCK-8 has affinity for both CCKA and CCKB receptor subtypes, we wanted to determine the subtype involved in CCK-8-induced TAC.
View Article and Find Full Text PDFHybrid analogs of the cholecystokinin A (CCK-A) receptor selective tetrapeptide agonist Boc-Trp-Lys(Tac)-Asp-MePhe-NH2 (1,A-71623) and the CCK-B receptor selective antagonists PD-135118 (2) and CI-988 (3) were prepared. Incorporation of the Lys(Tac) side chain into 2 produced a moderately potent antagonist of CCK-8 in the isolated guinea pig gallbladder (GPGB). Incorporation of the Lys(Tac) side chain into 3 produced the novel agonist analog 7 (EC50 = 28 nM in the GPGB) with excellent affinity for both human CCK-A (IC50 = 12 nM) and CCK-B (IC50 = 17 nM) receptors.
View Article and Find Full Text PDFWe compared the effects of intraperitoneally administered LiCl (0.5-2830 mumol/kg), sulfated cholecystokinin26-33 (10-1000 nmol/kg; CCK-8), nonsulfated CCK-8 (500 and 1000 nmol/kg), sulfated CCK26-29 (500 and 1000 nmol/kg), CCK30-33 (10-1000 nmol/kg) bombesin (10-1000 nmol/kg; BOM), (dl) fenfluramine HCl (0.9-37.
View Article and Find Full Text PDFUsing a one-bottle taste aversion conditioning paradigm, sulfated cholecystokinin(26-33) (CCK-8) has again been shown to induce taste aversion conditioning in rats. Even though the effective doses of CCK-8 are relatively high, they do not induce as strong an aversion as has been demonstrated with LiCl. This pharmacodynamic profile of CCK-8 (i.
View Article and Find Full Text PDFThe projection fields of corticotropin-releasing factor (CRF)-containing perikarya in the rat central nervous system were studied using a combination of electrolytic lesions, microdissection and radioimmunoassay. The effects of bilateral electrolytic lesions of the central nucleus of the amygdala (Ce) or the paraventricular nucleus (PVN) of the hypothalamus were measured by a sensitive and specific radioimmunoassay. Following lesions of the Ce, CRF concentrations in the locus ceruleus (LC) were significantly decreased.
View Article and Find Full Text PDFPediatr Res
February 1991
Amniotic fluid volume is regulated by a balance of fetal fluid production and resorption. Although fetal swallowing is believed to be a major site of fluid resorption, additional routes of fluid exchange also may contribute. In our present study, five chronically prepared, water-restricted, pregnant ewes with singleton fetuses (128 +/- 1 d) were rehydrated via an intraamniotic infusion (100 mL/h over 90 min) of 0.
View Article and Find Full Text PDFA number of studies have shown that intracisternal, intracerebroventricular, or direct administration of neurotensin (NT) into the nucleus accumbens (ACC) can antagonize the arousal and excitement produced by activation of the mesolimbic dopamine (DA) system of rats. This study investigated where NT acts relative to DA neurons to exert this antagonistic effect. In this study we selectively removed the majority of limbic forebrain DA terminals by bilateral administration of 6-hydroxydopamine (6-OHDA) into the anterolateral hypothalamus of desipramine-pretreated rats.
View Article and Find Full Text PDFJ Pharmacol Exp Ther
April 1988
Moderate taste aversions were induced by pairing the initial consumption of 0.25% sodium saccharin (SACC) with either 25 mg/kg i.p.
View Article and Find Full Text PDFProg Neuropsychopharmacol Biol Psychiatry
July 1989
1. Neurotensin (NT) is a tridecapeptide that fulfills many of the requisite criteria for neurotransmitter status in the mammalian central nervous system. 2.
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