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  • 1
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Serratia sp. ATCC 39006 (39006) uses a complex hierarchical regulatory network allowing multiple inputs to be assessed before genes involved in secondary metabolite biosynthesis are expressed. This taxonomically ill-defined Serratia sp. produces a carbapenem antibiotic (Car; a β-lactam) and a red pigmented antibiotic, prodigiosin (Pig; a tripyrrole), which are controlled by the smaIR quorum sensing (QS) locus. SmaR is a repressor of Pig and Car when levels of N-acyl- l-homoserine lactones, produced by SmaI, are low. In this study, we demonstrate direct DNA binding of purified SmaR to the promoter of the Car biosynthetic genes and abolition of this binding by the QS ligand. We have also identified multiple new secondary metabolite regulators. QS controls production of secondary metabolites, at least in part, by modulating transcription of three genes encoding regulatory proteins, including a putative response regulator of the GacAS two-component signalling system family, a novel putative adenylate cyclase and Rap (regulator of antibiotic and pigment). Mutations in another gene encoding a novel predicted global regulator, pigP, are highly pleiotropic; PigP has a significant ‘master’ regulatory role in 39006 where it controls the transcription of six other regulators. The PigP protein and its homologues define a new family of regulators and are predicted to bind DNA via a helix-turn-helix domain. There are regulatory overlaps between the QS and PigP regulons that enable the information from different physiological cues to be funnelled into the control of secondary metabolite production.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    International journal of consumer studies 29 (2005), S. 0 
    ISSN: 1470-6431
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: Research evidence suggests that UK consumers are facing significant problems with goods and services and are in need of information and advice to avoid or redress such situations. Consumers are not always aware of their rights nor where they can access consumer advice services. In 2000, the Department of Trade and Industry launched the Consumer Support Network (CSN) programme in Great Britain to improve consumer access to expert, accurate and timely advice. One challenge faced by these Networks and many other agencies is to assess the needs of consumers for consumer information and advice services. A needs assessment is required as a key element in the effective planning and development of services in each Network at a local level. The focus of the needs assessment at the local level is to encourage Networks to consider suitable solutions to meet the needs of people in their communities. This paper provides a review of the development of Consumer Support Networks in Great Britain and discusses the importance of needs assessment to service providers such as CSNs and other agencies. It reveals the complexity associated with conducting effective needs assessments including the various aspects of needs, consumer segmentation and characteristics of consumer information and advice. Further research is being carried out at Queen Margaret University College, UK, with a view to the development of a scientific model for the assessment of need for consumer information and advice services.
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    International journal of consumer studies 29 (2005), S. 0 
    ISSN: 1470-6431
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
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  • 4
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Gene flow and dispersal among populations of a stone-cased caddis (Tasimiidae: Tasimia palpata) were estimated indirectly using a 460 bp region of the cytochrome oxidase I gene of mitochondrial DNA.2. There was no significant differentiation at the largest spatial scale (between catchments) and no correlation between genetic distance and geographic distance. These results are consistent with widespread adult dispersal.3. Conversely, significant genetic differentiation was detected at the smallest spatial scale examined (among reaches within streams). This pattern was primarily because of significant FST values in a single stream (Bundaroo Creek).4. Bundaroo Creek also had the lowest mean number of haplotypes per population (n = 7) suggesting that a limited number of females may be responsible for recruitment at these sites. Significant FST's at the reach scale may be a result of this ‘patchy’ recruitment. However, additional evidence regarding the long-range dispersal ability and fecundity of T. palpata females is needed to test this hypothesis fully.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Conspecific populations living in habitats with different risks of predation often show phenotypic variation in defensive traits. Traits of two species of mayflies (Baetidae: Baetis bicaudatus and Baetis sp. nov.) differ between populations living in fish and fishless streams in a high altitude drainage basin in western Colorado, U.S.A. We tested for genetic differentiation between mayfly populations in these two habitat types, assuming that lack of genetic differentiation would be consistent with the hypothesis that those traits are phenotypically plastic.2. Previous work has shown that larvae of both species behave differently and undergo different developmental pathways in adjacent fish and fishless streams. These phenotypic differences in behaviour and development have been induced experimentally, suggesting that populations from fishless streams have the genetic capability to respond to fish.3. During summer 2001 we collected Baetis larvae from several fish and fishless streams, and from fish and fishless sections of the same streams. We used allozymes and a fragment of the cytochrome oxidase subunit 1 mitochondrial gene to examine genetic variation of Baetis individuals within and among streams.4. Results showed that genetic variation exists among populations of the same species of Baetis from different streams, but none of that variation was associated with the presence or absence of fish. These data confirm that populations of Baetis living in fish and fishless streams are not genetically distinct, and are consistent with the hypothesis that traits associated with environments of different risk are phenotypically plastic.
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  • 6
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Using spatial predictions of future threats to biodiversity, we assessed for the first time the relative potential impacts of future land use and climate change on the threat status of plant species. We thus estimated how many taxa could be affected by future threats that are usually not included in current IUCN Red List assessments. Here, we computed the Red List status including future threats of 227 Proteaceae taxa endemic to the Cape Floristic Region, South Africa, and compared this with their Red List status excluding future threats. We developed eight different land use and climate change scenarios for the year 2020, providing a range of best- to worst-case scenarios. Four scenarios include only the effects of future land use change, while the other four also include the impacts of projected anthropogenic climate change (HadCM2 IS92a GGa), using niche-based models. Up to a third of the 227 Proteaceae taxa are uplisted (become more threatened) by up to three threat categories if future threats as predicted for 2020 are included, and the proportion of threatened Proteaceae taxa rises on average by 9% (range 2–16%), depending on the scenario. With increasing severity of the scenarios, the proportion of Critically Endangered taxa increases from about 1% to 7% and almost 2% of the 227 Proteaceae taxa become Extinct because of climate change. Overall, climate change has the most severe effects on the Proteaceae, but land use change also severely affects some taxa. Most of the threatened taxa occur in low-lying coastal areas, but the proportion of threatened taxa changes considerably in inland mountain areas if future threats are included. Our approach gives important insights into how, where and when future threats could affect species persistence and can in a sense be seen as a test of the value of planned interventions for conservation.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well-known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high-risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility.The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first-step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Trypanosoma brucei relies on antigenic variation of its variant surface glycoprotein (VSG) coat for survival. We show that VSG switching can be efficiently studied in vitro using VSG RNAi in place of an immune system to select for switch variants. Contrary to models predicting an instant switch after inhibition of VSG synthesis, switching was not induced by VSG RNAi and occurred at a rate of 10−4 per division. We find a highly reproducible hierarchy of VSG activation, which appears to be capable of resetting, whereby more than half of the switch events over 12 experiments were to one of two VSGs. We characterized switched clones according to switch mechanism using marker genes in the active VSG expression site (ES). Transcriptional switches between ESs were the preferred switching mechanism, whereby at least 10 of the 17 ESs identified in T. brucei 427 can be functionally active in vitro. We could specifically select for switches mediated by DNA rearrangements by inducing VSG RNAi in the presence of drug selection for the active ES. Most of the preferentially activated VSGs could be activated by multiple mechanisms. This VSG RNAi-based procedure provides a rapid and powerful means for analysing VSG switching in African trypanosomes entirely in vitro.
    Type of Medium: Electronic Resource
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  • 10
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