743 research outputs found
Incorporating Wikipedia in the Classroom to Improve Science Learning and Communication
Wikipedia, the digital encyclopedia, has approximately 15 billion page views a month and is a platform where editors worldwide collaborate to improve content on topics, including the questions above. Wikipedia supports science communication in several ways. It helps readers comprehend information and contributors clarify the meaning and implications of scientific knowledge. The anatomy of Wikipedia is symmetric, allowing for ease in contribution and discussion. Wikipedia-based assignments range from making small edits, such as copyediting a series of science-related topics, adding citations, or inserting internal links to existing Wikipedia pages, to more substantial contributions. Challenges faced by students necessitate \u27just-in-time instruction on reference reliability, content incorporation, and rules regarding plagiarism. Students in \u27Natural Disturbances and Society\u27 are tasked to contribute content to a series of disturbance articles on Wikipedia based on research in primary literature. Substantial contribution to Wikipedia can be as simple as locating and expanding a Stub, short undeveloped articles on a notable topic
Mitefauna (Arachnida: Acari) associated to grapevine, Vitis vinifera L. (Vitaceae), in the municipalities of Bento Gonçalves and Candiota, Rio Grande do Sul, Brazil.
The mitefauna associated to Merlot and Chardonnay grapevine cultivars and associated plants in the municipalities of Bento Gonçalves and Candiota, Rio Grande do Sul was investigated. The study was developed between October 2006 and September 2007, where 20 grapevine plants were randomly chosen from each municipality and monthly sampled. Three leaves of each plant were taken. A total of 11,598 mites belonging to 14 families and to 52 species were found. Fifty-nine percent of the total specimens were collected in Candiota, being 93% associated to the Merlot cultivar. Higher species richness was observed on associated plants. Phytoseiidae showed the highest species richness, with ten species, and Eriophyidae showed the highest abundance, with 8,675 specimens. Calepitrimerus vitis (Nalepa, 1905) and polyphagotarsonemus latus (Banks, 1904) were the most common phytophagous mites, while Neoseiulus californicus (McGregor, 1954) and Pronematus anconai (Baker, 1943) were the most common predators
Availability of soil mutualists may not limit nonânative Acacia invasion but could increase their impact on native soil communities
The availability of compatible mutualistic soil microbes could influence the invasion success of non-native plant species. Specifically, there may be spatial variation in the distribution of compatible microbes, and species-specific variation in plant host ability to associate with available microbes. Although either or both factors could promote or limit invasion, the scale over which most studies are conducted makes it difficult to examine these two possibilities simultaneously. However, this is critical to identifying a role of soil microbes in invasion. A series of recent research projects focused on interactions between Australian Acacia and nitrogen-fixing bacteria (rhizobia) at multiple spatial scales, from the local to the inter-continental, has allowed us to evaluate this question. Collectively, this research reveals that nodulation, performance and rhizobial community composition are all broadly similar across spatial scales and differentially invasive species. Synthesis and applications. We argue that current research provides convincing evidence that interactions with rhizobia do not determine invasion success in Acacia, but instead highlights key knowledge gaps that remain unfilled. Importantly, the ease with which non-native Acacia species form mutualistic associations with rhizobia, regardless of invasive status, highlights the critical need to understand the impacts of all non-native Acacia on native soil communities
Host promiscuity in symbiont associations can influence exotic legume establishment and colonization of novel ranges
Aim Invasive Acacia species have negatively impacted natural areas in multiple regions around the globe. Almost 400 Acacia species have been introduced outside their native ranges in Australia; approximately 6% have become invasive, 12% are naturalized, and 82% have no record of naturalization or invasion. This variation in invasiveness provides a comparative framework in which to examine mechanisms that either promote or constrain establishment and colonization of species in novel regions. Here, we experimentally examine the role that the legumeârhizobia symbiosis plays in the differential invasiveness of acacias introduced outside their native Australian ranges. Location Canberra, Australia. Methods We paired 12 Acacia species ranging in invasiveness globally with 12 rhizobial strains ranging in average symbiotic effectiveness. We measured plant growth and nodulation success and abundance to assess whether invasive acacias were more promiscuous hosts, that is had positive growth and nodulation responses to a broader range of rhizobial strains than naturalized and non-invasive species. Results Invasive acacias had a higher growth response across more rhizobial strains (six of 12 strains) than naturalized and non-invasive species, but invasiveness categories differed only moderately with regard to the percentage of plants with nodules and nodulation abundance. Main conclusion With respect to plant growth, invasive acacias appear to be more promiscuous hosts than naturalized and non-invasive Australian Acacia species. Plant growth response to nodulation, however, is likely more important than nodulation alone in the successful invasion of species in novel ranges. Results from this study help elucidate an important mechanism in the invasive capacity of legumes
Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts
Identification of mechanisms that allow some species to outcompete others is a fundamental goal in ecology and invasive species management. One useful approach is to examine congeners varying in invasiveness in a comparative framework across native and invaded ranges. Acacia species have been widely introduced outside their native range of Australia, and a subset of these species have become invasive in multiple parts of the world. Within specific regions, the invasive status of these species varies. Our study examined whether a key mechanism in the life history of Acacia species, the legume-rhizobia symbiosis, influences acacia invasiveness on a regional scale. To assess the extent to which species varying in invasiveness correspondingly differ with regard to the diversity of rhizobia they associate with, we grew seven Acacia species ranging in invasiveness in California in multiple soils from both their native (Australia) and introduced (California) ranges. In particular, the aim was to determine whether more invasive species formed symbioses with a wider diversity of rhizobial strains (i.e. are more promiscuous hosts). We measured and compared plant performance, including aboveground biomass, survival, and nodulation response, as well as rhizobial community composition and richness. Host promiscuity did not differ among invasiveness categories. Acacia species that varied in invasiveness differed in aboveground biomass for only one soil and did not differ in survival or nodulation within individual soils. In addition, acacias did not differ in rhizobial richness among invasiveness categories. However, nodulation differed between regions and was generally higher in the native than introduced range. Our results suggest that all Acacia species introduced to California are promiscuous hosts and that host promiscuity per se does not explain the observed differences in invasiveness within this region. Our study also highlights the utility of assessing potential mechanisms of invasion in speciesâ native and introduced ranges
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Soft topographic map for clustering and classification of bacteria
In this work a new method for clustering and building a
topographic representation of a bacteria taxonomy is presented. The method is based on the analysis of stable parts of the genome, the so-called âhousekeeping genesâ. The proposed method generates topographic maps of the bacteria taxonomy, where relations among different
type strains can be visually inspected and verified. Two well known DNA alignement algorithms are applied to the genomic sequences. Topographic maps are optimized to represent the similarity among the sequences according to their evolutionary distances. The experimental analysis is carried out on 147 type strains of the Gammaprotebacteria
class by means of the 16S rRNA housekeeping gene. Complete sequences of the gene have been retrieved from the NCBI public database. In the experimental tests the maps show clusters of homologous type strains and present some singular cases potentially due to incorrect classification
or erroneous annotations in the database
Some like it hot: population-specific adaptations in venom production to abiotic stressors in a widely distributed cnidarian
Background: In cnidarians, antagonistic interactions with predators and prey are mediated by their venom, whose synthesis may be metabolically expensive. The potentially high cost of venom production has been hypothesized to drive population-specific variation in venom expression due to differences in abiotic conditions. However, the effects of environmental factors on venom production have been rarely demonstrated in animals. Here, we explore the impact of specific abiotic stresses on venom production of distinct populations of the sea anemone Nematostella vectensis (Actiniaria, Cnidaria) inhabiting estuaries over a broad geographic range where environmental conditions such as temperatures and salinity vary widely.
Results: We challenged Nematostella polyps with heat, salinity, UV light stressors, and a combination of all three factors to determine how abiotic stressors impact toxin expression for individuals collected across this speciesâ range. Transcriptomics and proteomics revealed that the highly abundant toxin Nv1 was the most downregulated gene under heat stress conditions in multiple populations. Physiological measurements demonstrated that venom is metabolically costly to produce. Strikingly, under a range of abiotic stressors, individuals from different geographic locations along this latitudinal cline modulate differently their venom production levels.
Conclusions: We demonstrate that abiotic stress results in venom regulation in Nematostella. Together with anecdotal observations from other cnidarian species, our results suggest this might be a universal phenomenon in Cnidaria. The decrease in venom production under stress conditions across species coupled with the evidence for its high metabolic cost in Nematostella suggests downregulation of venom production under certain conditions may be highly advantageous and adaptive. Furthermore, our results point towards local adaptation of this mechanism in Nematostella populations along a latitudinal cline, possibly resulting from distinct genetics and significant environmental differences between their habitats.publishedVersio
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