37 resultados para HOST-SPECIFICITY

em Deakin Research Online - Australia


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Nucleotide variation in a portion of the mitochondrial cytochrome c oxidase subunit1 (cox1) gene from asexual stages of bucephalids of southern Australian scallops (Chlamys asperrima, Chlamys bifrons and Pecten fumatus) was investigated using a mutation scanning–sequencing approach. Single-strand conformation polymorphism (SSCP) analysis revealed three main profile types (A, B and C) for parasites isolated from scallops. Sequence analysis revealed that samples represented by profiles B and C had a high degree (97.3%) of sequence similarity, whereas they were ~21% different in sequence from those represented by profile A. These findings suggested that at least two types or species (represented by profile A, or profile B or C) of bucephalid infect scallops, of which both were detected in South Australia, while only one was found in Victoria. The prevalence of bucephalids (and their SSCP haplotypes) appeared to differ among the three species of scallop in South Australia as well as between the two scallop species in Victoria, indicating a degree of host specificity. Adult bucephalids were collected from Eastern Australian Salmon (Arripis trutta), in an attempt to match them with the asexual stages from the scallop hosts. Neither of the two taxa of adult bucephalid (Telorhynchus arripidis and an un-named Telorhynchus species) shared SSCP profiles with the bucephalids from scallops, but were genetically similar, suggesting that the asexual stages from scallops may represent the genus Telorhynchus. This study, which assessed nucleotide sequence variation in a portion of the mitochondrial cox1 gene for bucephalids found in scallops and arripid fish, illustrates the usefulness of the mutation scanning approach to elucidate complex life-cycles of marine parasites.

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An important Athecate genus, Eudendrium, and a group of species of the Thecata, the latter ecologically related by life on a common substrate, are reviewed. Eudendrium, hitherto poorly known in Australia, comprises 17 species, including 10 undescribed species with 71% Australian, and high provincial endemicity. Eudendrium may be a shelf genus avoiding turbulent oceanic waters. Species of Eudendrium are predominantly epizoic and some gregariously settling colonies may live for five years. Identification of sterile material is refined by using the cnidome in a key to classification. The species and population dynamics of hydroid epiphytes of the endemic southern Australian marine angiosperm Amphibolis were investigated with revision of historically vexatious taxa. In contrast with the northern hemisphere, no Athecata are associated with southern Australian seagrasses. Seventeen species from eight thecate families are associated with the two species of Amphibolis, including one undescribed species, H&lecium amphibolum, and one new record for Australia, Aglaophenia postdentata. The Lineolariidae is revised and a new genus, Millardaria, erected for a species from seagrass in Madagascar. The high endemicity (58%) and host-specificity of hydroids to Amphibolis is an evolutionary consequence of isolation of the seagrass dating from break-up of the Tethyan Sea. Hydroids occur throughout the year in the Amphibolis leaf canopy with a mean annual epiphytism of 44% on A. antarctica in the eastern continent and 86% in the western continent; epiphytism is 52% on A. griffithii in the western continent. Half of the eight important species are dominant epiphytes across the southern continent but the species and order of abundance varies regionally. Most are pioneer colonists with short, repetetive life-cycles lasting from weeks to a few months. Three species epiphytise the seagrass stems but only one is a leaf-canopy dominant. The canopy community comprises small, fast-growing species or dwarfed variants of species larger in other habitats: these ecomorphically constant forms are associated only with seagrass. Strategies for survival in the harsh Amphibolis environment include adnate colonies and gonothecae adnate or recumbent to the substrate, marked strengthening of the hydrorhiza, various hydrodynamic adaptations of the hydrotheca, early maturation and production of numerous small ova.

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Lectins are proteins/glycoproteins of non-immune origin that agglutinate red blood cells, lymphocytes, fibroblasts, etc., and bind reversibly to carbohydrates present on the apposing cells. They have at least two carbohydrate binding sites and their binding can be inhibited by one or more carbohydrates. Owing to carbohydrate binding specificity of lectins, they mediate cell-cell interactions and play role in protozoan adhesion and host cell cytotoxicity, thus are central to the pathogenic property of the parasite. Several parasitic protozoa possess lectins which mediate parasite adherence to host cells based on their carbohydrate specificities. These interactions could be exploited for development of novel therapeutics, targeting the adherence and thus helpful in eradicating wide spread of protozoan diseases. The current review highlights the present state knowledge with regard to protozoal lectins with an emphasis on their haemagglutination activity, carbohydrate specificity, characteristics and also their role in pathogenesis notably as adhesion molecules, thereby aiding the pathogen in disease establishment.

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The synthesis of the first example of an organotin double ladder (6) containing a functional group within the spacer is reported. In the solid state, compound 6 shows an interlaminar cavity whose size and shape suggest the possibility of host–guest chemistry. 119Sn-NMR and ESMS show that compound 6 undergoes extensive dissociation in solution. ESMS of compound 6 to which have been added Li+, Na+, Mg2+ or Cu2+ show only minimal interaction.


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Many destinations are now using special events as integral components of their marketing strategies. The aim of this study was to explore how  attendance at a special event might impact perceptions of the host destination. Using a case study approach, this research explored the nexus between special events, their attendees and special event destinations. This research specifically focused on exploring whether attendance at a special event influences resulting perceptions of the host destination. The results of a survey-based study indicate that for almost a quarter of respondents who resided outside the host destination, their perceptions of the host destination had changed. Over 90% of these respondents indicated that these post-consumption perceptions of the host destination were more favourable than they were before attendance at the event. Key reasons provided by respondents for their changes in perceptions included Access, the Special Event itself and Attractions at the destination. The paper concludes that the synergies between the special event and the host destination can be likened to those of the celebrity and the products that they endorse and promote, and this notion should be further explored. Recommendations were made to assist marketers of host destinations to more effectively capitalise on the synergies between special events and destinations.

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Combining exercise with calcium supplementation may produce additive or multiplicative effects at loaded sites; thus, we conducted a single blind, prospective, randomized controlled study in pre- and early-pubertal girls to test the following hypotheses. (1) At the loaded sites, exercise and calcium will produce greater benefits than exercise or calcium alone. (2) At non-loaded sites, exercise will have no benefit, whereas calcium with or without exercise will increase bone mass over that in exercise alone or no intervention. Sixty-six girls aged 8.8 ± 0.1 years were randomly assigned to one of four study groups: moderate-impact exercise with or without calcium or low-impact exercise with or without calcium. All participants exercised for 20 minutes, three times a week and received Ca-fortified (434 ± 19 mg/day) or non-fortified foods for 8.5 months. Analysis of covariance (ANCOVA) was used to determine interaction and main effects for exercise and calcium on bone mass after adjusting for baseline bone mineral content and growth in limb lengths. An exercise-calcium interaction was detected at the femur (7.1%, p < 0.05). In contrast, there was no exercise-calcium interaction detected at the tibia-fibula; however, there was a main effect of exercise: bone mineral content increased 3% more in the exercise than non-exercise groups (p < 0.05). Bone mineral content increased 2-4% more in the calcium-supplemented groups than the non-supplemented groups at the humerus (12.0% vs. 9.8%, respectively, p < 0.09) and radius-ulna (12.6% vs. 8.6%, respectively, p < 0.01). In conclusion, greater gains in bone mass at loaded sites may be achieved when short bouts of moderate exercise are combined with increased dietary calcium, the former conferring region-specific effects and the latter producing generalized effects.

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Ecological models are now used to understand the complex array of factors that influence physical activity, resulting in a greater emphasis on environmental correlates. This selective review examines whether the predictive capacity of these models could be improved if behavior-specific measures of the environment were used to predict context-specific behaviors.

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Protein–protein interactions are often mediated by the recognition of short continuous amino acid stretches on target proteins by specific binding domains. Affinity-based selection strategies have successfully been used to define recognition motifs for a large series of such protein domains. However, in many biological systems specificity of interaction may be of equal or greater importance than affinity. To address this issue we have developed a peptide library screening technology that can be used to directly define ligands for protein domains based on both affinity and specificity of interaction. We demonstrate the value of this approach by the selection of peptide ligands that are either highly specific for the Grb2 Src homology 2 (SH2) domain or that are cross-reactive between a group of related SH2 domains. Examination of previously identified physiological ligands for the Grb2 SH2 domain suggests that for these ligands regulation of the specificity of interaction may be an important factor for in vivo ligand selection.

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Chronic hepatitis C virus (HCV) infection is a major burden on humanity. The current HCV therapy has limited efficacy, and there is pressing need for new and more effective therapies. Host cell factors that are required for HCV infection, replication and/or pathogenesis represent potential therapeutic targets. Of particular interest are cellular receptors that mediate HCV entry, factors that facilitate HCV replication and assembly, and intracellular pathways involving lipid biosynthesis, oxidative stress and innate immune response. A crucial challenge now is to manipulate such cellular targets pharmacologically for chronic HCV treatment, without being limited by side effects.

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During the 1990s, states embraced legalised gambling as a means of supplementing state revenue. But gaming machines (EGMs, pokies, VLTs, Slots) have become increasingly controversial in countries such as Australia, Canada and New Zealand, which experienced unprecedented roll-out of gaming machines in casino and community settings; alongside revenue windfalls for both governments and the gambling industry. Governments have recognised that gambling results in a range of social and economic harms and, similar to tobacco and alcohol, have introduced public policies predicated on harm minimisation. Yet despite these, gaming losses have continued to climb in most jurisdictions, along with concerns about gambling-related harms. The first part of this article discusses an emerging debate in Ontario Canada, that draws parallels between host responsibility in alcohol and gambling venues. In Canada, where government owns and operates the gaming industry, this debate prompts important questions on the role of the state, duty of care and regulation ‘in the public interest’ and on CSR, host responsibility and consumer protection. This prompts the question: Do governments owe a duty of care to gamblers?

The article then discusses three domains of accumulating research evidence to inform questions raised in the Ontario debate: evidence that visible behavioural indicators can be used with high confidence to identify problem gamblers on-site in venues as they gamble; new systems using player tracking and loyalty data that can provide management with high precision identification of problem gamblers and associated risk (for protective interventions); and research on technological design features of new generation gaming products in interaction with players, that shows how EGM machines can be the site for monitoring/protecting players. We then canvass some leading international jurisdictions on gambling policy CSR and consumer protection.

In light of this new research, we ask whether the risk of legal liability poses a tipping point for more interventionist public policy responses by both the state and industry. This includes a proactive role for the state in re-regulating the gambling industry/products; instituting new forms of gaming machine product control/protection; and reinforcing corporate social responsibility (CSR) and host responsibility obligations on gambling providers – beyond self-regulatory codes. We argue the ground is shifting, there is new evidence to inform public policy and government regulation and there are new pressures on gambling providers and regulators to avail themselves of the new technology – or risk litigation

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Bis(3-endo-camphoryl)phosphinic acid (1) was prepared by the reaction of the lithium enolate of D-(+)-camphor and phosphorous trichloride followed by an oxidative work up. Compound 1 crystallizes from wet toluene as monohydrate 1·H2O, which was investigated by X-ray crystallography. Molecules of 1 are associated by strong hydrogen bonds giving rise to the formation of a supramolecular helix. The interior channel of the helix is filled by a one-dimensional (1D) string of water molecules that are also associated by hydrogen bonding. The 1D string adopts a twisted zigzag conformation. Although the hydrogen bond networks are not cross-linked both the screw of the helix and the twist of the 1D string of water molecules are left-handed (M) and controlled by the chiral camphoryl residues situated on the exterior of the helix. The overall supramolecular structure is strongly reminiscent of aquaporin-1, a significant membrane-channel protein responsible for the transport of water into the cells.

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The event sector has often come under the scrutiny of the public. A cursory glance at print and electronic media highlights some of the many negative attitudes social commentators and residents of host destinations have of special events. While there are a number of stakeholders of events, two entities which play a pivotal role in whether, when, and how events are delivered are the event governing bodies (or owners) and the host destinations. This paper examines the relationship between these two stakeholders. Research questions guiding this study are: Do event owners vary in their interactions with event destinations? Should event destinations be more discerning in their selection of the events they host? Can event destinations be more discerning in their selection of the events that they bid for?

While considerable research has focused on the relationship between event owners and host destinations during the event bidding process, this study aimed to explore the relationship more generally to provide greater insights into the event planning process. Thus, the study aimed to address a gap in knowledge about event marketing and management to understand motives for destinations to engage with event owners, and ultimately to enhance the quality of the event experience (for both attendees and non-attendees). A qualitative research approach was employed for this study, with elite interviews being the main data collection method.

The findings indicate that the relationship between event owners and host destinations can be highly problematic. A number of factors were identified as contributing to this situation, including the varying objectives that event owners have for their events; the way in which these objectives are congruent (or not) with host destinations objectives for events in their community; and the way in which a potential match or mis-match of objectives impacts a host destination’s ability to leverage an event. Overall, the researchers concluded that when there is disparity between the culture of the event owners’ organisation, and the social culture of the host destination, this situation is exacerbated. When event owners demonstrated empathy and an understanding of the host destination’s culture, and an understanding of the host destination’s aim for delivering an event, greater levels of perceived success are evident.

In the past, the bid process has been highly competitive. Host destinations have been at the mercy of event owners. However, the authors of this study indicate that as a result of this research, host destinations should be more discerning with regard to which event owners they ‘lie in bed with’ to ensure that the outcomes of the events are beneficial for their myriad stakeholders. It is acknowledged that the event planning and execution process is set within a political market square, as per Larson and Wikstrom’s (2001) suggestion, and that this context provides a fertile ground for research on this topic.