325 resultados para Louise Fluk
Resumo:
We report two new occurrences of Mysis salemaai, a conservationally important glacial relict at the southern limit of its range, in Castlewellan Lake and Lough Scolban, in the North of Ireland. This increases the number of lakes in Ireland where the species has been recorded to thirteen. We consider lake area and maximum lake depth as factors that might determine the long-term survival of M. salemaai populations and show that these populations tend to occur in relatively large, deep, lakes. We also show that population densities in Lough Neagh and Lough Erne are declining.
Resumo:
Oyster populations around the world have seen catastrophic decline which has been largely attributed to overexploitation, disease and pollution. While considerable effort and resources have been implemented into restoring these important environmental engineers, the success of oyster populations is often limited by poor understanding of site-specific dispersal patterns of propagules. Water-borne transport is a key factor controlling or regulating the dispersal of the larval stage of benthic marine invertebrates which have limited mobility. The distribution of the native oyster Ostrea edulis in Strangford Lough, Northern Ireland, together with their densities and population structure at subtidal and intertidal sites has been documented at irregular intervals between 1997 and 2013. This paper revisits this historical data and considers whether different prevailing environmental conditions can be used to explain the distribution, densities and population structure of O. edulis in Strangford Lough. The approach adopted involved comparing predictive 2D hydrodynamic models coupled with particle tracking to simulate the dispersal of oyster larvae with historical and recent field records of the distribution of both subtidal and intertidal, populations since 1995. Results from the models support the hypothesis that commercial stocks of O. edulis introduced into Strangford Lough in the 1990s resulted in the re-establishment of wild populations of oysters in the Northern Basin which in turn provided a potential source of propagules for subtidal populations. These results highlight that strategic site selection (while inadvertent in the case of the introduced population in 1995) for the re-introduction of important shellfish species can significantly accelerate their recovery and restoration.
Resumo:
There is a pressing need to understand and optimize biological control so as to avoid over-reliance on the synthetic chemical pesticides that can damage environmental and human health. This study focused on interactions between a novel biocontrol-strain, Bacillus sp. JC12GB43, and potato-pathogenic Phytophthora and Fusarium species. In assays carried out in vitro and on the potato tuber, the bacterium was capable of near-complete inhibition of pathogens. This Bacillus was sufficiently xerotolerant (water activity limit for growth = 0.928) to out-perform Phytophthora infestans (~0.960) and challenge Fusarium coeruleum (~0.847) and Fusarium sambucinum (~0.860) towards the lower limits of their growth windows. Under some conditions, however, strain JC12GB43 stimulated proliferation of the pathogens: for instance, Fusarium coeruleum growth-rate was increased under chaotropic conditions in vitro (132 mM urea) by >100% and on tubers (2-M glycerol) by up to 570%. Culture-based assays involving macromolecule-stabilizing (kosmotropic) compatible solutes provided proof-of-principle that the Bacillus may provide kosmotropic metabolites to the plant pathogen under conditions that destabilize macromolecular systems of the fungal cell. Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells. Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field-relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields. These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode-of-behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.
Resumo:
FMRFamide-like peptide (FLP) receptors are appealing as putative anthelmintic targets. To date, 31 flp-encoding genes have been identified in Caenorhabditis elegans and thirteen FLP-activated G-protein coupled receptors (FLP-GPCRs) have been reported. The lack of knowledge on FLPs and FLP-GPCRs in parasites impedes their functional characterisation and chemotherapeutic exploitation. Using homology-based BLAST searches and phylogenetic analyses this study describes the identification of putative flp and flp-GPCR gene homologues in 17 nematode parasites providing the first pan-phylum genome-based overview of the FLPergic complement. These data will facilitate FLP-receptor deorphanisation efforts in the quest for novel control targets for nematode parasites.
Resumo:
We describe, for the first time, stimuli-responsive hydrogel-forming microneedle (MN) arrays that enable delivery of a clinically-relevant model drug (ibuprofen) upon application of light. MN arrays were prepared using a polymer prepared from 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) by micromolding. The obtained MN arrays showed good mechanical properties. The system was loaded with up to 5% (w/w) ibuprofen included in a light-responsive 3,5-dimethoxybenzoin conjugate. Raman spectroscopy confirmed the presence of the conjugate inside the polymeric MN matrix. In vitro, this system was able to deliver up to three doses of 50 mg of ibuprofen upon application of an optical trigger over a prolonged period of time (up to 160 hours). This makes the system appealing as a controlled release device for prolonged periods of time. We believe that this technology has potential for use in ?on-demand? delivery of a wide range of drugs in a variety of applications relevant to enhanced patient care.
Resumo:
Background: Candidal species, particularly Candida albicans are common pathogens in the oral cavity and perioral region. Many of the manifestations of candidiasis are associated with the formation of Candida biofilms on host surfaces and/or implanted biomaterials. Biofilms are clinically important due to their increased resistance to therapeutic intervention and the ability of cells within the biofilm to withstand host immune defences.
Objectives: The present study was designed to investigate the antifungal activity of two peptides found in skin secretions of the African volcano frog (Xenopus amieti) against the type strain of C. albicans NCTC 3179.
Methods: The antifungal activity of magainin-AM1 and peptide glycine-leucine-amide (PGLa-AM1) against C. albicans NCTC 3179 was studied in both planktonic and biofilm forms. Radial diffusion assays were used to obtain the minimum inhibitory concentration (MIC) of magainin-AM1 and PGLa-AM1 against planktonic C. albicans. Time kill assays were used to determine the time dependent fungicidal action of the peptides at both 4oC and 37oC. A 96 well microtitre plate model for candidal biofilm formation was employed to study the ability of the peptides to disrupt the early biofilm development (up to 24 hours) compared with the antifungal drug fluconazole. Biofilm formation was determined quantitatively using the crystal violet assay.
Results: Both magainin-AM1 and PGLa-AM1 demonstrated inhibitory activity against Candida albicans, with MIC values of 24.3 uM and 7.5uM respectively. Time-kill assays revealed bactericidal activity of both peptides at 37oC and 4oC. Magainin-AM1 and PGLa-AM1 inhibited biofilm formation in microtitre plate assays. The peptides were particularly effective during early biofilm establishment when compared with fluconazole treatment.
Conclusions: Magainin-AM1 and PGLa-AM1 are active against C albicans in both planktonic and biofilm forms. Further testing of this peptide family against candidal biofilms is recommended.
Resumo:
The resolution of evolutionary relationships among deep-sea incirrate octopuses has been hindered by the paucity of individuals available for morphological studies and by the lack of tissue samples preserved using fixatives compatible with simple DNA extraction techniques. Evolutionary relationships from 11 species of deep-sea incirrate octopuses were investigated using 2392 base pairs (bp) of DNA from four mitochondrial genes (12S rDNA, 16S rDNA, cytochrome c oxidase subunit III, and cytochrome b) and the nuclear gene, rhodopsin. Morphological examination of these species was also undertaken. Molecular analyses distinguish a species of octopus from hydrothermal vents at Manus Basin from the vent octopodid Vulcanoctopus hydrothermalis known from vents on the East Pacific Rise. Both are herein considered members of the clade currently assigned the name Benthoctopus, although taxonomic implications preclude formally naming Vulcanoctopus as a junior synonym. Morphological investigations led to the conclusion that Benthoctopus macrophallus is a junior synonym of Benthoctopus yaquinae. An amended diagnosis of Benthoctopus is provided with additional information on male reproductive characteristics. Copyright © 2009 · Magnolia Press.
Resumo:
Research points to a relationship between lateralization and emotional functioning in humans and many species of animal. The present study explored the association between paw preferences and emotional functioning, specifically temperament, in a species thus far overlooked in this area, the domestic cat. Thirty left-pawed, 30 right-pawed, and 30 ambilateral pet cats were recruited following an assessment of their paw preferences using a food-reaching challenge. The animals’ temperament was subsequently assessed using the Feline Temperament Profile (FTP). Cats’ owners also completed a purpose-designed cat temperament (CAT) scale. Analysis revealed a significant relationship between lateral bias and FTP and CAT scale scores. Ambilateral cats had lower positive (FTP+) scores, and were perceived as less affectionate, obedient, friendly, and more aggressive, than left or right-pawed animals. Left and right pawed cats differed significantly on 1 trait on the CAT scale, namely playfulness. The strength of the cats’ paw preferences was related to the animals’ FTP and CAT scores. Cats with a greater strength of paw preference had higher FTP + scores than those with a weaker strength of paw preference. Animals with stronger paw preferences were perceived as more confident, affectionate, active, and friendly than those with weaker paw preferences. Results suggest that motor laterality in the cat is strongly related to temperament and that the presence or absence of lateralization has greater implications for the expression of emotion in this species than the direction of the lateralized bias.
Resumo:
The shallow water kelp Laminaria digitata, abundant in coastal zones of the North Atlantic, is exposed to a range of hydrodynamic environments that makes it ideal for assessing the role of water motion on their growth rate. Here we quantify the growth of L. digitata, as a factor of blade and stipe elongation, at sites adjacent to Strangford Lough, Northern Ireland under different hydrodynamic conditions over a one year period. A modelling approach was used to numerically determine both the temporal and spatial variability of the hydrodynamic environment. Ambient seawater nutrient concentrations, temperature and irradiance were measured as well as the internal nutrient status of the L. digitata populations. Kelp populations growing in the greatest and lowest water motion showed the lowest growth rates. Differences observed in growth rate could not be attributed to seawater nutrient availability, temperature or light. The internal nutrient status also suggested no influence on the observed differences in growth rate. Therefore if there are minimal differences in light, temperature and nutrients between sites, then populations of L. digitata exposed to different water motions are likely to exhibit different growth rates. It is suggested that the growth rate differences observed were a function of water motion with the possibility that, in response to the hydrodynamic forces experienced by the algal cells, L. digitata kelps in the high energy environments were putting more energy into strengthening cell walls rather than blade elongation
Resumo:
Background: Little is known about prescribing appropriateness for community-dwelling people with dementia (PWD).
Objective To estimate potentially inappropriate prescribing (PIP) prevalence among PWD in primary care in Northern Ireland, and to investigate associations between PIP and polypharmacy, age and gender.
Methods: A retrospective cross-sectional study was conducted, using data from the Enhanced Prescribing Database. Patients were eligible if a medicine indicated for dementia management was dispensed to them during 01/01/2013 – 31/12/2013. Polypharmacy was indicated by use of ≥4 repeat medications from different drug groups. A subset of the Screening Tool of Older Persons Potentially Inappropriate Prescriptions (STOPP) criteria, comprising 36 indicators, was applied to the dataset. Overall prevalence of PIP and the prevalence per each STOPP criterion was calculated as a proportion of all eligible persons in the dataset. Logistic regression was used to investigate associations between PIP, polypharmacy, age and gender.
Results: The study population comprised 6826 patients. Polypharmacy was observed in 81.5% (n=5564) of patients. PIP prevalence during the study period was 64.4% (95% CI 63.2 – 65.5; n=4393). The most common instance of PIP was the use of anticholinergic/antimuscarinic medications (n=1718; 25.2%; 95% CI 24.2 – 26.2). In multivariable analyses, both polypharmacy and gender (being female) were associated with PIP, with odds ratios of 7.6 (95% CI 6.6 – 8.7) and 1.3 (95% CI 1.2 – 1.4) respectively. No association was observed between PIP and age, after adjustments for gender and polypharmacy.
Conclusion: This study identified a high prevalence of PIP in community-dwelling PWD. Future interventions may need to focus on certain therapeutic categories and polypharmacy.