Anthropogenic or natural disturbances can have a significant impact on wild animals. Therefore, understanding when, how and what type of human and natural events disturb animals is a central problem ...in wildlife conservation. However, it can be difficult to identify which particular environmental stressor affects an individual most. We use heart rate telemetry to quantify the energy expenditure associated with different types of human-mediated and natural disturbances in a breeding passerine, the white-eyed vireo (Vireo griseus). We fitted 0.5 g heart rate transmitters to 14 male vireos and continuously recorded heart rate and activity for two days and three nights on a military installation. We calibrated heart rate to energy expenditure for five additional males using an open-flow, push-through respirometry system showing that heart rate predicted 74 per cent of energy expenditure. We conducted standardized disturbance trials in the field to experimentally simulate a natural stressor (predator presence) and two anthropogenic stressors. Although birds initially showed behavioural and heart rate reactions to some disturbances, we could not detect an overall increase in energy expenditure during 1- or 4-hours disturbances. Similarly, overall activity rates were unaltered between control and experimental periods, and birds continued to perform parental duties despite the experimental disturbances. We suggest that vireos quickly determined that disturbances were non-threatening and thus showed no (costly) physiological response. We hypothesize that the lack of a significant response to disturbance in vireos is adaptive and may be representative of animals with fast life histories (e.g. short lifespan, high reproductive output) so as to maximize energy allocation to reproduction. Conversely, we predict that energetic cost of human-mediated disturbances will be significant in slow-living animals.
Role of nitric oxide under saline stress: implications on proline metabolism Lopez-Carrion, A.I.,University of Granada (Spain). Dept. of Plant Physiology; Castellano, R.,University of Granada (Spain). Dept. of Plant Physiology; Rosales, M.A.,University of Granada (Spain). Dept. of Plant Physiology ...
Biologia plantarum,
09/2008, Letnik:
52, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The present work is focused on the possible relationship between nitric oxide and the induction of proline in response to salt stress. Brassica rapa plants were subjected to 100 mM NaCl and sodium ...nitroprusside (SNP; the donor of NO) at different concentrations. The plants showed lower NaCl-induced oxidative stress and proline accumulation after application of low concentrations of SNP together with the NaCl treatment. The reduction in the proline content was related to increased activity of proline dehydrogenase. These results suggest that the NO could be capable of mitigating damage associated with salt stress.
Background and objective: The HLA‐DRB1*15 allele is consistently associated with multiple sclerosis (MS) susceptibility in most studied populations. This study investigated the association between ...HLA‐DRB1 alleles and the presence of oligoclonal immunoglobulin G bands (OCB) in the cerebrospinal fluid (CSF) in a Spanish population with MS.
Methods: The HLA‐DRB1 typing was performed in 268 patients with sporadic MS and the detection of OCB in CSF. HLA‐DRB1 allelic frequencies were compared between OCB‐positive and OCB‐negative patients, and both groups were also compared with 1088 unrelated healthy controls. Moreover, we correlated the various HLA‐DRB1 genotypes, considering all the combinations of both parental alleles found with the presence or absence of OCB.
Results: We found 206 OCB‐positive and 62 OCB‐negative patients. The HLA‐DRB1*15 allele in OCB‐positive patients had a higher frequency when compared with OCB‐negative patients (39.3% in OCB‐positive vs. 16.1% in OCB‐negative, OR = 1.38 95% CI = 1.18–1.61, P < 0.001). The other alleles did not show differences. When we compared with controls, the HLA‐DRB1*15 allele was associated with the disease only in the OCB‐positive patients group. None of the 55 genotypes found showed any association with the presence or absence of OCB.
Conclusions: HLA‐DRB1*15 allele is associated with OCB‐positive patients with MS when studying a Spanish MS population.
Glucocorticoid hormones such as corticosterone (CORT) play crucial roles in many physiological processes. CORT's actions are primarily mediated via binding to two receptors (glucocorticoid receptors ...(GRs) and mineralocorticoid receptors (MRs)) in different target tissues. CORT receptors can be independently regulated from circulating hormone titres, from tissue to tissue and even within different regions of the same tissue type. Increasing evidence has shown relationships between circulating CORT and melanin-based pigmentation in skin and feathers, yet to our knowledge, there have been no studies of CORT receptors in the skin of melanized ornaments. Male house sparrows (Passer domesticus) have a black, melanized bib, and evidence suggests that bib size is an important intraspecific signal. We examined the relationship between bib area and tissue sensitivity to CORT by quantifying GR and MR in bib skin and in adjacent paler-feathered belly skin (as a control tissue) at different life-history stages using radioligand binding assays. Males with larger bibs relative to their life-history stage had less GR in bib skin, but not belly skin, than males with smaller bibs. These results suggest a connection between the size of a melanin-based ornament and the underlying tissue's responsiveness to CORT.
Corticosterone (CORT) is seasonally modulated in many passerines, with plasma CORT concentrations lowest during the prebasic molt, when all feathers are replaced. Recent evidence indicating that CORT ...implants slow the rate of feather regrowth in molting birds suggests that plasma CORT concentrations are downregulated during molt in order to avoid the inhibition of feather growth caused by the protein catabolic activity of CORT. To further test this hypothesis, we examined whether endogenous CORT release, stimulated by exposure to either psychological stress or physical stress (food restriction), could inhibit feather regrowth rates or decrease feather quality in birds undergoing an induced molt (feather replacement after plucking). European starlings (Sturnus vulgaris) were exposed to chronic psychological stress or food restriction for three weeks of the feather regrowth period. Throughout this time, the length of growing primary, secondary, and tail feathers was measured and blood samples were collected to measure baseline and stress-induced CORT concentrations. Upon completion of growth, feather quality was analyzed via measurements of mass, rachis length, feather area, and presence of fault bars. Both psychological and physical stress protocols elevated circulating plasma CORT but significantly less than implants from an earlier study did. Psychological stress had no effect on feather regrowth rates or feather quality. Food restriction had no effect on feather growth rate but caused asynchronous feather replacement. When combined with psychological stress, physical stress also resulted in smaller feather area. Results indicate that CORT implants may not accurately represent chronic stress physiology. Additionally, the purpose for downregulating CORT concentrations during molt appears to be more complicated than simply protecting feather production from CORT's catabolic effects.
A common social impairment in individuals with ASD is difficulty interpreting and or predicting emotions of others. To date, several interventions targeting teaching emotion recognition and ...understanding have been utilized both by researchers and practitioners. The results suggest that teaching emotion recognition is possible, but that the results do not generalize to non-instructional contexts. This study sought to replicate earlier findings of a positive impact of teaching emotion recognition using a computer-based intervention and to extend it by testing for generalization on live models in the classroom setting.
Two boys and one girl, four to eight years in age, educated in self-contained classrooms for students with communication and social skills deficits, participated in this study. A multiple probe across participants design was utilized. Measures of emotion recognition and understanding were assessed at baseline, intervention, and one month post-intervention to determine maintenance effects. Social validity was assessed through parent and teacher questionnaires.
All participants showed improvements in measures assessing their recognition of emotions in faces, generalized knowledge to live models, and maintained gains one month post intervention.
These preliminary results are encouraging and should be utilized to inform a group design, in order to test efficacy with a larger population.
•Unsupported MoS2 catalysts are obtained from n-methylenediammonium-thiomolybdates.•Catalysts from carbon-containing precursors yield higher activities than those from ATM.•The MS-HeDa catalyst (from ...the precursor with six methylenes) has the largest k of the series.•Excess carbon in the MS-OcDa catalyst (from the precursor with eight methylenes) lowers HDS activity.
Carbon-containing MoS2 catalysts with specific surface areas of up to 32.4m2/g are prepared in situ from ethylenediammonium thiomolybdate (EtDaT, n=2), 1,4-butane-diammonium thiomolybdate (BuDaT, n=4), 1,6-hexanediammonium thiomolybdate (HeDa, n=6), and 1,8-octanediammonium thiomolybdate (OcDaT, n=8), where BuDaT and OcDaT are novel precursors. The n-methylenediammonium thiomolybdates are prepared by reacting ammonium thiomolybdate (ATM) with ethylenediamine, 1,4-butanediamine, 1,6-hexane-diamine and 1,8-octanediamine, respectively, in an aqueous medium containing NH4Cl. Catalysts, as characterized by XRD and TEM, present a well-dispersed 2H-MoS2 phase. For the hydrodesulfurization (HDS) of dibenzothiophene (DBT), their first order rate constants, k, are more than two times higher than that of the reference catalyst (32.0×10−7mol/g·s) derived from carbon-free ATM, with the MS-HeD catalyst being the most active k=86.3×10−7mol/g·s.
The use of carbohydrases and proteases in poultry production occasionally results
in inconsistent physiological responses that are difficult to explain. However,
it has previously been demonstrated ...that a substantial portion of the variation
in enzyme efficacy is associated with the inherent ileal digestibility of
starch, protein and lipid, and so an appreciation for the concentration of the
undigested fractions of these nutrients in a diet may help to determine the
magnitude and consistency of feed enzyme responses. Considering that the expense
of in vivo physiological assays for the assessment of enzyme
functional pattern is high, it is crucial to develop suitable in
vitro methods to predict the magnitude of enzyme response. The purpose
of the current paper is to describe inherent characteristics of poultry diets
and feed ingredients in response to carbohydrases and proteases in order to aid
the development of in vitro assays to predict feed enzyme
functional patterns.
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