bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissecting the β-Aminobutyric Acid–Induced Priming Phenomenon in Arabidopsis
Authors: Ton Jurriaan , Jakab Gabor , Toquin Valérie , Flors Victor , Iavicoli Annalisa , Maeder Muriel N. , Métraux Jean-Pierre , Mauch-Mani Brigitte 
Published: February 2005

Abstract
Plants treated with the nonprotein amino acid β-aminobutyric acid (BABA) develop an enhanced capacity to resist biotic and abiotic stresses. This BABA-induced resistance (BABA-IR) is associated with an augmented capacity to express basal defense responses, a phenomenon known as priming. Based on the observation that high amounts of BABA induce sterility in Arabidopsis thaliana, a mutagenesis screen was performed to select mutants impaired in BABA-induced sterility (ibs). Here, we report the isolation and subsequent characterization of three T-DNA–tagged ibs mutants. Mutant ibs1 is affected in a cyclin-dependent kinase–like protein, and ibs2 is defective in AtSAC1b encoding a polyphosphoinositide phosphatase. Mutant ibs3 is affected in the regulation of the ABA1 gene encoding the abscisic acid (ABA) biosynthetic enzyme zeaxanthin epoxidase. To elucidate the function of the three IBS genes in plant resistance, the mutants were tested for BABA-IR against the bacterium Pseudomonas syringae pv tomato, the oomycete Hyaloperonospora parasitica, and BABA-induced tolerance to salt. All three ibs mutants were compromised in BABA-IR against H. parasitica, although to a different extent. Whereas ibs1 was reduced in priming for salicylate (SA)-dependent trailing necrosis, mutants ibs2 and ibs3 were affected in the priming for callose deposition. Only ibs1 failed to express BABA-IR against P. syringae, which coincided with a defect in priming for SA-inducible PR-1 gene expression. By contrast, ibs2 and ibs3 showed reduced BABA-induced tolerance to salt, which correlated with an affected priming for ABA-inducible gene expression. For all three ibs alleles, the defects in BABA-induced sterility and BABA-induced protection against P. syringae, H. parasitica, and salt could be confirmed in independent mutants. The data presented here introduce three novel regulatory genes involved in priming for different defense responses.
Preventing youth access to alcohol: outcomes from a multi‐community time‐series trial*
Authors: Wagenaar Alexander C. , Toomey Traci L. , Erickson Darin J. 
Published: February 2005

ABSTRACTAims/intervention  The Complying with the Minimum Drinking Age project (CMDA) is a community trial designed to test effects of two interventions designed to reduce alcohol sales to minors: (1) training for management of retail alcohol establishments and (2) enforcement checks of alcohol establishments.Design  CMDA is a multi‐community time‐series quasi‐experimental trial with a nested cohort design.Setting/participants  CMDA was implemented in 20 cities in four geographic areas in the US Midwest.Measurements  The core outcome, propensity for alcohol sales to minors, was directly tested with research staff who attempted to purchase alcohol without showing age identification using a standardized protocol in 602 on‐premise and 340 off‐premise alcohol establishments. Data were collected every other week in all communities over 4 years. Mixed‐model regression and Box–Jenkins time‐series analyses were used to assess short‐ and long‐term establishment‐specific and general community‐level effects of the two interventions.Findings  Effects of the training intervention were mixed. Specific deterrent effects were observed for enforcement checks, with an immediate 17% reduction in likelihood of sales to minors. These effects decayed entirely within 3 months in off‐premise establishments and to an 8.2% reduction in on‐premise establishments.Conclusions  Enforcement checks prevent alcohol sales to minors. At the intensity levels tested, enforcement primarily affected specific establishments checked, with limited diffusion to the whole community. Finally, most of the enforcement effect decayed within 3 months, suggesting that a regular schedule of enforcement is necessary to maintain deterrence.
Should nortriptyline be used as a first‐line aid to help smokers quit? Results from a systematic review and meta‐analysis
Authors: Wagena E. J. , Knipschild P. , Zeegers M. P. A. 
Published: February 2005

ABSTRACTObjectives  The objective of this paper is to evaluate the efficacy of nortriptyline for smoking cessation compared to placebo and bupropion sustained release.Data sources  Randomized trials were identified by (1) checking electronic and (2) online publicly accessible registers of clinical trials; (3) searching references of identified studies and screening abstract books of conferences and symposia, and (4) personal communication with the first authors of identified papers.Review methods  We included randomized trials in which nortriptyline was compared to placebo or bupropion hydrochloride SR. The main clinical outcome measure was (at least) 6‐month prolonged abstinence, confirmed with a biochemical test. To investigate the efficacy of nortriptyline in time, we calculated the percentage of smokers who relapsed in time.Results  We identified five randomized trials, including 861 smokers. Compared to placebo medication, nortriptyline resulted in significantly higher prolonged abstinence rates after at least 6 months [relative risk (RR) = 2.4, 95% CI 1.7–3.6; RD = 0.11, 95% CI 0.07–0.15]. The difference in efficacy between nortriptyline and placebo was highest in the first months after the target quit date. However, the number of people who remained abstinent decreased substantially and significantly faster over time in the nortriptyline group. Although bupropion resulted in higher abstinence rates compared with nortriptyline, the difference was not statistically significant (RR = 1.7, 95% CI 0.7–4.1).Conclusion  This systematic review and meta‐analysis shows that the use of nortriptyline for smoking cessation resulted in higher prolonged abstinence rates after at least 6 months compared to placebo treatment. Furthermore, the use of nortriptyline for smoking cessation is well tolerated and safe. As a result, we believe health care professionals should be recommended to prescribe nortriptyline as a first‐line therapy for smoking cessation, also because of the much lower cost of nortriptyline compared to bupropion SR.
Demographic variation and biomass allocation of Agropyron cristatum grown on steppe and dune sites in the Hunshandake Desert, North China
Authors: Wang R. Z. 
Published: February 2005

AbstractDemographic and biomass allocation patterns of Agropyron cristatum were measured on steppe and dune sites in the Hunshandake desert of North China in 2001 and 2002. Total plant population, reproductive shoot densities and its differentiation rates were significantly higher in the steppe sites in both years. Plant heights for both vegetative and reproductive shoots were greater in the year with the higher rainfall. The dune sites had a higher biomass allocation to vegetative shoots and roots, while the steppe sites had a higher biomass allocation to reproductive shoots and seed production. It is suggested that the population demography and biomass allocation of the species responded to the differences in the soil variables in the steppe and dune sites.
Response of herbage regrowth and water‐soluble carbohydrate concentration of ryegrass species to defoliation practices when grown in a Mediterranean environment
Authors: Callow M. N. , Michell P. , Baker J. E. , Cocks P. S. , Hough G.M. 
Published: February 2005

AbstractThree experiments were conducted to determine the association between leaf number per tiller at defoliation, water‐soluble carbohydrate (WSC) concentration and herbage mass of juvenile ryegrass plants when grown in a Mediterranean environment. Seedlings of ryegrass were grown in nursery pots arranged side‐by‐side and located outside in the open‐air to simulate a mini‐sward in Experiments 1 and 2, and a mixture of annual ryegrass and subterranean clover (Trifolium subterraneum L.) was grown in a small plot field study in Experiment 3. Swards were defoliated mechanically with the onset of defoliation commencing within 28 d of germination. Frequency of defoliation ranged from one to nine leaves per tiller, whilst defoliation height ranged from 30 mm of pseudostem height that removed all leaf laminae in Experiment 1, to 50 mm of pseudostem height with some leaf laminae remaining post‐defoliation in Experiments 2 and 3.A positive relationship between herbage mass of ryegrass, WSC concentration and leaf number per tiller at defoliation was demonstrated in all experiments. In Experiment 1, the herbage mass of leaf, pseudostem and roots of tillers defoliated at one leaf per tiller was reduced to 0·10, 0·09 and 0·06 of those tillers defoliated less frequently at six leaves per tiller. However, the reduction in herbage mass from frequent defoliation was less severe in Experiment 2 and coincided with a 0·20 reduction in WSC concentration of pseudostem compared with 0·80 measured during Experiment 1. In Experiment 3, the highest harvested herbage mass of ryegrass occurred when defoliation was nine leaves per tiller. Although the harvested herbage from this sward contained senescent herbage, the in vitro dry‐matter digestibility of the harvested herbage did not differ significantly compared with the remaining treatments that had been defoliated more frequently.Leaf numbers of newly germinated ryegrass tillers in a Mediterranean environment were positively associated with WSC concentration of pseudostem and herbage mass. A minimum period of two to three leaf appearances was required to restore WSC concentrations to levels measured prior to defoliation thereby avoiding a significant reduction in herbage mass. However, maximum herbage mass of a mixed sward containing ryegrass and subterranean clover was achieved when defoliation was delayed to nine leaves per tiller.
Melanotrope Cells of Xenopus laevis Express Multiple Types of High‐Voltage‐Activated Ca2+ Channels
Authors: Zhang H.‐Y. , Langeslag M. , Voncken M. , Roubos E. W. , Scheenen W. J. J. M. 
Published: February 2005

AbstractPituitary melanotrope cells are neuroendocrine signal transducing cells that translate physiological stimuli into adaptive hormonal responses. In this translation process, Ca2+ channels play essential roles. We have characterised which types of Ca2+ current are present in melanotropes of the amphibian Xenopus laevis, using whole‐cell, voltage‐clamp, patch‐clamp experiments and specific blockers of the various current types. Running an activation current–voltage relationship protocol from a holding potential (HP) of −80 mV/or −110 mV, shows that Xenopus melanotropes possess only high‐voltage activated (HVA) Ca2+ currents. Steady‐state inactivation protocols reveal that no inactivation occurs at −80 mV, whereas 30% of the current is inactivated at −30 mV. We determined the contribution of individual channel types to the total HVA Ca2+ current, examining the effect of each channel blocker at an HP of −80 mV and −30 mV. At −80 mV, ω‐conotoxin GVIA, ω‐agatoxin IVA, nifedipine and SNX‐482 inhibit Ca2+ currents by 21.8 ± 4.1%, 26.1 ± 3.1%, 24.2 ± 2.4% and 17.9 ± 4.7%, respectively. At −30 mV, ω‐conotoxin GVIA, nifedipine and ω‐agatoxin IVA inhibit Ca2+ currents by 33.8 ± 3.0, 24.2 ± 2.6 and 16.0 ± 2.8%, respectively, demonstrating that these blockers substantially inhibit part of the Ca2+ current, independently from the HP. We have previously demonstrated that ω‐conotoxin GVIA can block Ca2+ oscillations and steps. We now show that nifedipine and ω‐agatoxin IVA do not affect the intracellular Ca2+ dynamics, whereas SNX‐482 reduces the Ca2+ step amplitude. We conclude that Xenopus melanotrope cells express all four major types of HVA Ca2+ channel, as well as the resulting currents, but no low‐voltage activated channels. The results provide the basis for future studies on the complex regulation of channel‐mediated Ca2+ influxes into this neuroendocrine cell type as a function of its role in the animal's adaptation to external challenges.
Phytoestrogen Action in the Adult and Developing Brain
Authors: Patisaul H. B. 
Published: February 2005

AbstractSoy isoflavonoids are plant phytoestrogens available as dietary supplements and are increasingly advocated as a natural alternative to oestrogen replacement therapy. As weak oestrogen agonists/antagonists with a range of other enzymatic activities, the isoflavonoids provide a useful model to investigate the actions of endocrine disruptors. Here, the activational and organisational effects of these compounds on the brain are reviewed. In spite of their preferential affinity for oestrogen receptor (ER)βin vitro, isoflavonoids act in vivo through both ERα and ERβ. Their neurobehavioural actions are largely anti‐oestrogenic, either antagonising or producing an action in opposition to that of oestradiol. Small, physiologically relevant exposure levels can alter oestrogen‐dependent gene expression in the brain and affect complex behaviour in a wide range of species. The implications for these findings in humans, and particularly in infants, largely remain uninvestigated but are a subject of increasing public interest.
Introduction of a High‐Energy Diet Acutely Up‐Regulates Hypothalamic Cocaine and Amphetamine‐Regulated Transcript, Mc4R and Brown Adipose Tissue Uncoupling Protein‐1 Gene Expression in Male Sprague‐Dawley Rats
Authors: Archer Z. A. , Rayner D. V. , Duncan J. S. , Bell L. M. , Mercer J. G. 
Published: February 2005

AbstractObesity is an escalating problem in Western societies. Susceptibility to weight gain within an obesogenic environment is variable. It remains unclear how the range of weight gain responses are generated. It is possible that an individual's immediate and/or sustained appetite for apparently palatable foods, or metabolic adaptations to a new diet could be important. The present study therefore examined the short‐ to medium‐term effects of a high‐energy (HE) diet on bodyweight, food intake, and energy balance‐related signalling systems. Sprague‐Dawley rats were fed either chow or an HE diet for 12 h, 24 h, 48 h or 14 days. Blood hormones and metabolites were assayed, and expression of uncoupling protein‐1 (UCP‐1) and hypothalamic energy‐balance related genes were determined by Northern blotting or in situ hybridisation, respectively. Short‐term exposure (12 h, 24 h, 48 h) to the HE diet had no effect on grams of food consumed, but caloric intake was increased. Exposure to HE diet for 14 days (medium term) established a bodyweight differential of 7.7 g, and animals exhibited a transient increase in caloric intake of 5 days duration. Terminal levels of leptin, insulin, glucose and non‐esterified fatty acids (NEFAs) were all increased in HE‐fed animals. UCP‐1 mRNA was elevated in interscapular brown adipose tissue from HE‐fed rats only at 12 h. Cocaine and amphetamine‐regulated transcript (CART) and Mc4R gene expression in the hypothalamus were increased after 12 h and 24 h on an HE diet, respectively. The rats appear to passively over‐consume calories as a result of consuming a similar weight of a more energy dense food. This evokes physiological responses, which adjust caloric intake over several days. Circulating NEFA and insulin concentrations, UCP‐1, Mc4R and CART gene expression are increased as an immediate consequence of consuming HE diet, and may be involved in countering hypercaloric intake. Circulating leptin is increased in the HE‐fed animals after 48 h, reflecting their increasing adiposity.
Oestrogen Receptor β‐Immunoreactive Neurones in the Ovine Hypothalamus: Distribution and Colocalisation with Gonadotropin‐Releasing Hormone
Authors: Skinner D. C. , Dufourny L. 
Published: February 2005

AbstractOestrogen powerfully affects the secretion of gonadotropin‐releasing hormone (GnRH) from the brain in all species investigated, including sheep. Until recently, it was hypothesised that such regulation occurs indirectly because few or no GnRH neurones were found to express oestrogen receptor (ER) α. The discovery of a second oestrogen receptor, ERβ, and its subsequent localisation in numerous GnRH neurones in the rat, led to a reconsideration of this hypothesis. However, colocalisation of immunoreactive ERβ protein in GnRH neurones has only been demonstrated in the rat, raising the possibility that such putative direct regulation of GnRH neurones by oestrogen may be peculiar to this species. We have previously shown that steroid receptors in the sheep brain are acutely sensitive to fixation and the full complement of immunoreactive cells can only be visualised after antigen retrieval. The aims of this study were therefore to map immunocytochemically the distribution of ERβ neurones in the ewe brain, and to determine which proportion of GnRH neurones express ERβ. Brain sections (20 µm) from four ewes killed in anestrus were subjected to high temperature antigen retrieval and immunocytochemistry. Numerous ERβ‐immunoreactive cells were located throughout the hypothalamus and, following dual‐label immunocytochemistry, over 50% of the GnRH neurones were found to express immunoreactive ERβ. The functional significance of these ERβ‐expressing GnRH neurones in the ovine brain remains to be determined.
Reduced Activity of the Noradrenergic System in the Paraventricular Nucleus at the End of Pregnancy: Implications for Stress Hyporesponsiveness
Authors: Douglas A. J. , Meddle S. L. , Toschi N. , Bosch O. J. , Neumann I. D. 
Published: February 2005

AbstractWe investigated whether changes in noradrenaline neurotransmission in the hypothalamus could explain the hyporesponsiveness of the hypothalamic‐pituitary‐adrenal (HPA) axis in late pregnancy. Noradrenaline release within the hypothalamic paraventricular nucleus in response to swim stress, as estimated by microdialysis and high‐performance liquid chromatography, was lower in 20‐day pregnant rats compared to virgin rats. Driving a central noradrenergic pathway using intravenous cholecystokinin increased adrenocorticotropic hormone (ACTH) secretion in virgin rats, but the response was significantly less in 16‐day and 20‐day pregnant rats. Thus, the activity of noradrenergic inputs to the paraventricular nucleus and the HPA axis is attenuated in late pregnancy. The sensitivity of the HPA axis to noradrenaline in pregnancy was investigated by intracerebroventricular administration of an α1‐receptor antagonist, benoxathian, before and during exposure to swim stress. In virgin rats, benoxathian increased basal and stress‐induced ACTH secretion, but in late pregnant rats the benoxathian effects were attenuated, indicating reduced sensitivity of the HPA axis to noradrenaline neurotransmission and/or the inability of the system to become disinhibited at this time. α1A‐adrenoreceptor mRNA expression in the parvocellular and magnocellular paraventricular nucleus, measured by in situ hybridisation, was decreased in late pregnant compared to virgin rats. Additionally, blocking endogenous opioid inhibition with naloxone pretreatment restored the ACTH secretory response to cholecystokinin in pregnant rats. Thus, in late pregnancy, there is reduced noradrenergic input to the paraventricular nucleus and reduced α1A‐receptor expression in the paraventricular nucleus, both of which may contribute to the reduced responsiveness of the HPA axis in pregnancy.
Short Day Lengths Enhance Skin Immune Responses in Gonadectomised Siberian Hamsters
Authors: Prendergast B. J. , Bilbo S. D. , Nelson R. J. 
Published: February 2005

AbstractIn Siberian hamsters and other photoperiodic rodents, exposure to short photoperiods simultaneously inhibits gonadal hormone secretion and enhances some measures of immune function. The present study tested whether gonadal hormones mediate the effects of short days on skin immune function (delayed‐type hypersensitivity reactions) in male Siberian hamsters. The magnitude of delayed‐type hypersensitivity reactions was greater in hamsters exposed to short days relative to those in long days. Comparable effects of photoperiod were obtained in castrated hamsters bearing empty or testosterone‐filled implants. The data suggest that contemporary gonadal hormone secretion is neither necessary, nor sufficient to mediate the effects of short photoperiods on skin immune function.
Effects of GABABReceptor Modulation on Gonadotropin‐Releasing Hormone and β‐Endorphin Release, and on Catecholaminergic Activity in the Ventromedial Hypothalamus‐Infundibular Nucleus Region of Anoestrous Ewes
Authors: Tomaszewska‐Zaremba D. , Przekop F. 
Published: February 2005

AbstractTo examine the role of γ‐aminobutyric acid (GABA)Breceptor mediating systems in the ventromedial hypothalamus‐infundibular nucleus region (VMH/NI) of anoestrous ewes in controlling gonadotropin‐releasing hormone (GnRH) release, the extracellular concentrations of GnRH, β‐endorphin, norepinephrine, dopamine, 4‐hydroxy‐3‐methoxy‐glycol and 3,4‐dihydroxy‐phenylacetic acid were quantified during infusion of baclofen or phaclofen (agonist and antagonist of GABABreceptors, respectively) in this structure. The stimulation of GABABreceptors activates GnRH/luteinising hormone (LH) release, attenuates noradrenergic and β‐endorphinergic tone but has no evident effect on the dopaminergic system. Blockade of GABABreceptors in this structure increases the extracellular β‐endorphin concentration but has no significant influence on GnRH release or catecholaminergic activity. It is suggested that activation of GnRH/LH release in the VMH/NI of anoestrous ewes may result from a decrease of norepinephrine output and hence its inhibitory effect on GnRH secretion. Activation of GABABreceptors, as well as their blockade, did not change dopaminergic system activity, indicating that GABABdoes not affect GnRH release indirectly by a GABABreceptor mechanism acting on dopaminergic neurones in the VMH/NI. Increased activity of the β‐endorphinergic system during blockade of GABABreceptors does not change GnRH release, suggesting that β‐endorphin does not play a significant role in the control of GnRH secretion in anoestrous ewes.
Norepinephrine Release in Medial Amygdala Facilitates Activation of the Hypothalamic‐Pituitary‐Adrenal Axis in Response to Acute Immobilisation Stress
Authors: Ma S. , Morilak D. A. 
Published: February 2005

AbstractActivation of the brain noradrenergic system during stress plays an important integrative function in coping and stress adaptation by facilitating transmission in many brain regions involved in regulating behavioural and physiological components of the stress response. The medial amygdala (MeA) has been implicated in modulation of stress‐induced activation of the hypothalamic‐pituitary‐adrenal (HPA) axis, and MeA is a target of innervation from brainstem noradrenergic neurones. However, it is not known whether, and to what extent, activation of the ascending noradrenergic innervation of MeA might modulate stress‐induced adrenocorticotropic hormone (ACTH) secretion. In the first experiment in this study, we measured extracellular norepinephrine (NE) levels in MeA using in vivo microdialysis. The concentration of NE in dialysate samples collected in MeA was elevated by more than three‐fold over baseline in response to acute immobilisation stress, providing evidence of a possible modulatory role for NE in the MeA during stress. This potential role was then assessed in the second experiment by measuring changes in the elevation of plasma ACTH concentration induced by acute immobilisation stress immediately following bilateral microinjections of α1‐ or β‐adrenergic receptor antagonists directly into MeA. Compared to vehicle‐injected controls, the α1‐receptor antagonist benoxathian dose‐dependently and significantly attenuated the ACTH response to acute stress, whereas combined β1/β2‐receptor blockade in MeA had only a modest effect. These results indicate that MeA does play a role in the stress response, and support the hypothesis that stress‐induced activation of NE release in MeA, acting primarily through α1 receptors, facilitates activation of the HPA axis in response to acute stress.